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Aujourd’hui — 24 février 2020Massive Science

To fight agricultural pests, scientists try spray-on plant vaccines

Every year, between 20 and 40 percent of the world's food crops are lost to plant pests and pathogens. This leaves 821 million people without enough food to eat and costs the global economy around $220 billion, according to the Food and Agriculture Organization of the United Nations (FAO).

The spread of pests and diseases is exacerbated by climate change, which has an enormous impact on food supplies, alters ecosystems, and creates new niches where those pests can thrive. Driven by an altered ecosystem, insects and pests are likely to expand their range. Because of these severe threats to food security, scientists are always searching for sustainable solutions to safeguard crops.

In August 2019, a research group headed by Sven-Erik Behrens, from Martin-Luther-Universität in Halle-Wittenberg, Germany, announced the development of a rapid and reliable approach to creating a "vaccine" for plants. It can be sprayed on like a pesticide, or even injected like an animal vaccine.

It works using a system called RNA interference, or RNAi. RNAi can be thought of as a kind of immune system: the cell recognizes double-stranded RNA (a cousin of DNA that also carries genetic information) that's not its own, like that from a virus trying to take over a cell, and chops that RNA into small fragments. Then, the cell uses those fragments to identify and stop further pathogen activity. Interestingly, eukaryotic cells – like animals, plants, and fungi – also use RNAi to regulate their own genes, recognizing and suppressing their own RNA. This can turn off or even fine-tune gene expression, like a dimmer switch on a lamp.

Behrens's group recreated RNAi machinery in their laboratory using cultured tobacco plant cells and double-stranded RNA from TBSV (tomato bushy stunt virus). Then, they searched for the viral RNA which produced the strongest RNAi reaction in tobacco. Once identified, they carried out “vaccination" experiments, injecting that RNA into uninfected tobacco plants. They found that plants inoculated with the most powerful vaccine were protected at a rate of 90%.

Entomologist Wayne Buhler sweeps a soybean field for western corn rootworm adults—another way to scout a field to determine if insecticidal bait is needed.

A scientist sweeps a soybean field for corn rootworms.

Ken Hammond/USDA

So far, RNAi vaccination attempts have been based on genetically engineering plant genomes to express specific RNAs normally only seen in pests, so they grow already vaccinated. In 2017 the U.S. Environmental Protection Agency (EPA) approved a genetically engineered maize specifically engineered against corn rootworm. However, even if GMOs are recognized as safe, in some countries there are concerns about their use. Countries that have banned GMOs seek non-transgenic, sustainable alternatives for pest management strategies that can reduce pesticides use. By combining the spray-on easy-application typical of chemical pesticides with the precision offered by genetic engineering, plant “vaccines” based on RNAi represent sustainable alternative in plant protection where GMOs use is forbidden by policy regulations.

One of the major advantages of "vaccinating" plants is that RNA molecules can be externally delivered to plants, through topical application like a spray, stem injection, root drenching, or seed treatment. This simple delivery method gives RNAi plant "vaccines" another benefit: flexibility. Viruses and pathogens mutate continuously to adapt to changing environments; designing a tailored RNA "vaccine" would be quicker and easier than time consuming and laborious procedures needed for gene editing. This would be an advantage for perennial crops, such as grapevine, citrus trees, and apple trees, which often require years of experiments and are expensive to genetically modify. RNAi “vaccines” are also highly specific: only target pathogens are affected by treatments, while undesired effects on other organisms are expected to be limited.

Cassava mosaic disease (CMD) symptoms in a field in Tanzania.

Cassava mosaic disease (CMD) symptoms in a field in Tanzania.  

 H.Holmes/RTB via Flickr

Plant vaccinations would make an enormous difference for many commercially important staple crops threatened by viruses like rice, wheat, maize, sweet potato, cassava, and banana. For example, at least ten different species of viruses have been identified in cassava plants affected by cassava mosaic disease (CMD), which causes substantial yield losses and famines in east and central Africa and more recently in southeast Asia, threatening the livelihood of 800 million people worldwide.

Since eukaryotic pests like insects use RNAi to fine-tune or shut down their own genes, that can be used against them. And although RNAi can not be directly used against bacteria that infect plant (because bacteria don't use RNAi), it could be employed to control their insect vectors, which carry the bacteria with them, transporting it from an infected to a healthy plant. If an insect nibbles on a plant carrying RNA that shuts down a gene the insect needs to live, RNAi will function like a targeted, biodegradable pesticide.

This would be very useful in the case of bacterium Xylella fastidiosa, which causes a range of diseases in different plant species, like Pierce’s disease of grapevines, citrus variegated chlorosis, and olive quick decline syndrome. X. fastidiosa has recently spread in the Apulia region, in the southern part of Italy, where it is destroying centennial olive trees and threatening the local economy. However, it is estimated that up to 563 plant species belonging to 82 botanical families can host the bacterium. It is transmitted especially by insects who feed on sap, mainly sharpshooter leafhoppers (pictured at the top of the page) in America and the meadow spittle bug in Europe. To date, apart from prevention and containment measures, there is no known cure for Xylella fastidiosa. But, RNAi treatments have been able to protect crops from insect vectors of X. fastidiosa, and so may be a tool to control bacterial infections as well.

Further studies are needed to understand how RNA molecules can be produced in large, industrial quantities. However, RNAi plant "vaccines" are proving to be a highly engineered sustainable method to protect food crops. Perhaps soon, we'll see crop dusters filled to the brim with RNA.

Fabiola De Marchi studies



University of Padua


A glassy-winged sharpshooter, which transmits X. fastidiosa
Hier — 23 février 2020Massive Science

Unlike bacteria, diatoms are picky about microplastics

Good news for fans of microplastics in the ocean! The tiny fragments of discarded plastic waste that find their way into marine environments are providing a long-term habitat for aquatic microorganisms.

While working as a doctoral student at the Smithsonian Tropical Research Institute at Arizona State University, Kassandra Dudek studied the phenomenon of microplastics serving as artificial microbial reefs. Bacteria are known to form biofilms along these materials, building up stable, complex communities. Dudek’s newly published research intended to find out whether certain types of bacteria have preference for settling on certain types of plastic. This could for example influence the movement of pathogens through the environment. It is also relevant because only certain types of bacteria are thought to be able to deconstruct (metabolize) certain types of plastic.

Plastic garbage rainbow

All of these plastic objects shed microscopic plastic particles into the environment as they break down

Photo by Jasmin Sessler on Unsplash

The study showed that the five types of plastic tested, all deriving from common household waste items, did not show any detectable differences in the types of bacteria found colonizing their surfaces. This suggests that it is the physical surface of plastic that quickly attracts bacterial settlers, rather than any chemical features of the specific plastics tested.

However, the researchers also noted that microscopic photosynthetic algae known as diatoms did show strong preferences for just 1 or 2 types of plastic polymer, and that diatoms needed to be exposed to plastic for a lot longer than bacteria in order to colonize the plastic surface. This is significant because earlier research showed that bacteria that could degrade plastic are often found associated with diatoms. It also shows the importance of long-term experiments, as these diatoms could not be detected on the plastic surface until after several weeks of exposure.

Suspended particulate matter (SPM) in Thermaikos Gulf, Greece, 2004. Scanning electron microscope (SEM) backscattered images of SPM collected on a membrane filter (pore size 0.4 μm). Diatoms Chaetoceros spp. can be identified.

Suspended particulate matter (SPM) in Thermaikos Gulf, Greece, 2004. Scanning electron microscope (SEM) backscattered images of SPM collected on a membrane filter (pore size 0.4 μm). Diatoms Chaetoceros spp. can be identified.
À partir d’avant-hierMassive Science

Scientists use GPS satellites to track Greenland ice sheet melting

The first GPS satellite was launched in 1978, and was built to aid navigation by transmitting radio signals from space to Earth. In 2000, President Bill Clinton removed the system’s military encryption. Called “selective availability,” this encryption had prevented users from calculating position coordinates in real time. Today, there are 31 GPS satellites operated by the US, plus more from other countries, all producing freely-available data.

Dr. Gladys West - GPS

Meet Dr. Gladys West, the hidden figure behind your phone’s GPS. She is one of the reasons why you can receive driving directions from your phone or tag a photo location on Instagram.

By US Air Force

In recent years, radio scientists have found a way to use the GPS constellation for purposes far beyond its intended use. The bounce-backs of GPS signals can be used to measure soil moisture, sea surface height, sea ice, wind velocities, and snow depth. After bouncing off of the Earth, the weak return signals are received by other satellites and contain information about the surface they hit. This process is called the Global Navigation Satellite System Reflectometry (GNSS-R).

Now, researchers have developed a new method to measure melting of the Greenland ice sheet using the GNSS-R. 

Water reflects more microwave radiation than ice, causing stronger bounce-backs from melt regions. Researchers use this property to make maps of the reflectivity of the ice sheet during melt and non-melt seasons. Furthermore, the GPS signals can penetrate hundreds of feet into the ice, much deeper than existing measurements. As a result, the technique may be able to detect previously invisible subsurface melt, a new research area. 

Spaceborne sensors are notorious for unplanned failures. The ability to make melt measurements from military-backed GPS satellites will provide a useful and more securely funded point of comparison for conventional measurements, potentially at greater subsurface depths than before.  

GPS tracker on person's wrist

The lifesaving transplant organ you're waiting on may go missing in transit

When a human heart was left behind by mistake on a Southwest Airlines plane in 2018, transplant officials downplayed the incident. They emphasized that the organ was used for valves and tissues, not to save the life of a waiting patient, so the delay was inconsequential.

“It got to us on time, so that was the most important thing,” said Doug Wilson, an executive vice president for LifeNet Health, which runs the Seattle-area operation that processed the tissue.

That high-profile event was dismissed as an anomaly, but a new analysis of transplant data finds that a startling number of lifesaving organs are lost or delayed after being shipped on commercial flights, the delays often rendering them unusable.

In a nation where nearly 113,000 people are waiting for transplants, scores of organs — mostly kidneys — are discarded after they don’t reach their destination in time.

Between 2014 and 2019, nearly 170 organs could not be transplanted and almost 370 endured “near misses,” with delays of two hours or more, after transportation problems, according to an investigation by Kaiser Health News and Reveal from the Center for Investigative Reporting. The media organizations reviewed data from more than 8,800 organ and tissue shipments collected voluntarily and shared upon request by the United Network for Organ Sharing, or UNOS, the nonprofit government contractor that oversees the nation’s transplant system. Twenty-two additional organs classified as transportation “failures” were ultimately able to be transplanted elsewhere.

Surgeons themselves often go to hospitals to collect and transport hearts, which survive only four to six hours out of the body. But kidneys and pancreases — which have longer shelf lives — often travel commercial, as cargo. As such, they can end up missing connecting flights or delayed like lost luggage. Worse still, they are typically tracked with a primitive system of phone calls and paper manifests, with no GPS or other electronic tracking required.

“We’ve had organs that are left on airplanes, organs that arrive at an airport and then can’t get taken off the aircraft in a timely fashion and spend an extra two or three or four hours waiting for somebody to get them,” said Dr. David Axelrod, a transplant surgeon at the University of Iowa.

One contributing factor is the lack of a national system to transfer organs from one region to another because they match a distant patient in need.

Instead, the U.S. relies on a patchwork of 58 nonprofit organizations called organ procurement organizations, or OPOs, to collect the organs from hospitals and package them. Teams from the OPOs monitor surgeries to remove organs from donors and then make sure the organs are properly boxed and labeled for shipping and delivery.

From there, however, the OPOs often rely on commercial couriers and airlines, which are not formally held accountable for any ensuing problems. If an airline forgets to put a kidney on a plane or a courier misses a flight because he got lost or stuck in traffic, there is no consequence, said Ginny McBride, executive director of OurLegacy, an OPO in Orlando, Florida. 

A collection of organ models: kidneys, brain, neurons and more.

Scores of organs — mostly kidneys — are trashed each year and many more become critically delayed while being shipped on commercial airliners, a new investigation finds.

By Robina Weermeijer on Unsplash 

In an era when consumers can precisely monitor a FedEx package or a DoorDash dinner delivery, there are no requirements to track shipments of organs in real time — or to assess how many may be damaged or lost in transit.

“If Amazon can figure out when your paper towels and your dog food is going to arrive within 20 to 30 minutes, it certainly should be reasonable that we ought to track lifesaving organs, which are in chronic shortage,” Axelrod said.

For years, organs were distributed locally and regionally first, a system that resulted in wide disparities in organ waiting times across the country. In recent years, UNOS officials and the transplant community, with federal urging, have been working, organ by organ, to restructure how it’s done.

Amid those ongoing efforts to allocate organs more fairly — and, recently, a Trump administration effort to overhaul kidney care — the waste of some of these precious resources donated by good Samaritans has been overlooked. 

Donor families and waiting patients may never know what’s happened to an organ provided by a loved one or why a surgery is canceled at the last minute.

“We have been unaware of how many kidneys have been waylaid,” said McBride, of the Orlando procurement agency. “That’s not a number that’s been transparent to us.”

But, she added, she’s aware of the risk: “I say a prayer and hold my breath every time a kidney leaves our office.”

46 Minutes To Spare

In October, a kidney en route from McBride’s OPO in Florida to a patient in North Carolina missed its connection in Atlanta. The box was prominently marked as a human organ and displayed a phone number to call. Apparently unaware of the urgency, a Delta cargo worker merely set it aside for a later flight.

The waiting transplant surgeon in Greensboro, North Carolina, “was having a fit,” said Kim Young, the OurLegacy organ recovery coordinator. If the kidney didn’t get to the hospital by 7 a.m., he wouldn’t be able to use it. Both the risk of organ failure and the chance of death increase with every hour a kidney is out of the body.

McBride had to decide whether to charter a plane at a cost of $15,000 — or to find a courier to drive the kidney through the night. She settled on the road trip, and the organ arrived at 6:14 a.m. — with just 46 minutes to spare.

Delta Air Lines officials declined repeated requests to comment on its organ transport service or the specific incident McBride described.

Several domestic airlines, including Delta, United, American, Southwest and Alaska, provide special cargo services for organs with priority boarding, handling and monitoring. They all declined to comment on organ transportation.

The traveling public may not realize it, but thousands of transplant organs — mostly kidneys, but some pancreases — fly on commercial flights each year. Roger Brown, who runs the Organ Center at UNOS, estimates that as many as 10 organs for transplant are on the move this way every day.

Kidney organ model

Kidneys make up a large number of transplant organs.

By Robina Weermeijer on Unsplash 

UNOS handles about 1,800 of these organ and tissue shipments a year, of which 1,400 are kidneys. That’s a fraction of the nearly 40,000 organs transplanted in the U.S. last year, including more than 23,000 kidneys. About 1 in every 6 transplanted kidneys is shipped nationally, UNOS figures show.

Most of the time, the organs get where they’re going without incident, Brown said.

“We’re never going to get rid of flight delays. We’re never going to get rid of human error,” he said. “We’re never going to get rid of the person who’s [trying to be] a little too helpful and perhaps puts it someplace special, which then maybe creates issues downstream.”

Troubling Reports

Reports of trouble abound. In August, transplant officials at Medical City Dallas reported in a public forum that they’d lost three kidneys just that month because of problems with commercial flights.

“One organ was delayed due to weather and the next available flight wasn’t till the next day,” the report said. “Another organ made it to the airport, but was never placed on the intended flight. The third organ was mistakenly taken to the wrong airport and missed the intended flight.”

In Kentucky, transplant surgeon Dr. Malay Shah said a kidney traveling on Delta from Pensacola, Florida, via Atlanta, on Oct. 1 sat in the Lexington airport for three hours before he was notified it was there. No one had noticed the box with the label that said “human organ for transplant,” he said.

“It’s scary,” Shah said. “Organs traveling by this mechanism are treated as simply ‘baggage’ or ‘cargo.’”

Before the 9/11 terror attacks in 2001, OPO workers could take organs through airport security and see them loaded onto the plane from the passenger gate, McBride said. 

While anecdotes like Shah’s are common, there’s little data to show how often these transportation problems occur. No federal agency, including the Health Resources and Services Administration, or HRSA, which contracts with UNOS, requires monitoring of transportation for transplant organs.

“Matters involving the transportation methods used by organ procurement organizations (OPOs) are arranged directly between OPOs and transplant centers,” HRSA spokesperson David Bowman said in an email.

Airlines log organ shipments in internal booking systems and on cargo manifests, but those documents aren’t public and no summary is available, said Katherine Estep, communications director for Airlines for America, an industry trade group.

“Live human organs receive the highest priority designation,” she said in a statement.

Teams from organ procurement organizations, or OPOs, monitor surgeries to remove organs from donors and then make sure the organs are properly boxed and labeled for shipping and delivery. 

Hannah Norman/KHN Illustration; Labels courtesy of Ginny Mcbride  

UNOS researchers noted the impact of transportation problems in 2014. They found 30 organs discarded and 109 “near misses” between July 2014 and June 2015.

But the agency didn’t begin formally tracking transportation errors until 2016, when a new computer system came online. Before that, Organ Center staff kept track of problems informally, with pencil and paper, and the information wasn’t verified, Brown said.

Calls for closer tracking from within the system have been met with defensiveness — or apathy, said Brianna Doby, an organ transplant community consultant for the Johns Hopkins School of Medicine.

“If you talk out loud about organ issues, they say it will drive down donation rates,” Doby said. “It’s not OK for us to say, ‘Well, shipping is hard.’ That’s not an acceptable answer.”

A National Network

UNOS was established in 1984 after Congress enacted the National Organ Transplant Act to address a critical shortage of donor organs and to improve organ matching and placement. It called for a national network to ensure that organs that couldn’t be used in the area where they were donated, and would be transplanted to save lives elsewhere. Before that, many organs were lost simply because transplant teams couldn’t find compatible recipients in time.

The act established the national Organ Procurement and Transplantation Network and called for the OPTN to be operated by a private, nonprofit organization under federal contract. UNOS, which has held the contract since the inception of OPTN, is overseen by HRSA, an agency of the U.S. Department of Health and Human Services.

Today, UNOS typically handles organs with conditions that can make them hard to place. That can include organs from older donors or those with medical or other characteristics that make them difficult to match.

Map of the US

The National Organ Transplant Act called for a national network to ensure that organs that couldn’t be used in the area where they were donated, and instead would be transplanted to save lives elsewhere.

By Free-Photos from Pixabay  

Overall, about 7% of shipments handled by UNOS from July 2014 to November 2019 encountered transportation problems, the data obtained by KHN and Reveal showed. UNOS wouldn’t release details about individual shipments, including dates or places shipped or causes of the transportation failures or delays.

But Brown, of the UNOS Organ Center, said an internal analysis showed that more than half of the transportation problems were related to commercial airlines or airports. Of those, two-thirds were caused by weather delays, mechanical delays and flight cancellations.

About one-third of transportation problems were related to logistics providers or ground couriers, mostly delays of package pickups. The rest were related to the sender or receiver of the shipments. 

However, Brown said, poor outcomes can’t be blamed directly on transportation problems, even when they do occur.

“The delay could be the primary reason an organ wasn’t transplanted,” he said. “It could be a contributing factor or it could have nothing to do with the reason that the organ is not transplanted.”

Other transplant experts downplay the impact of transportation problems. Kelly Ranum, president of the Association of Organ Procurement Organizations, said she’s “surprised at how low” UNOS’ failure numbers are, considering the volume of kidneys shipped.

Dr. Kevin O’Connor, chief executive of LifeCenter Northwest, an OPO based in Seattle, said transportation problems are “minimal” compared with the other reasons organs — including about 3,500 donated kidneys — are discarded each year. These typically include biopsy findings, the inability to find a recipient and poor organ function.

“For over 30 years and literally tens of thousands of organs being transported,” he said, “I can count on the fingers of one hand the number of times that, because of a transportation glitch, an organ was ultimately not transplanted.”

Still, O’Connor acknowledged that “even one kidney being thrown away because of transportation errors is unacceptable.”

doctors taking blood pressure

Other than transit delays, organs can be discarded due to biopsy findings, the inability to find a recipient, and poor organ function.

Rawpixel.com on Pexels

Part of the problem lies with the way organs are transported now, said Axelrod, who also represents the American Society of Transplant Surgeons.

“We don’t have an end-to-end unified transportation system,” Axelrod said. “We don’t have a FedEx for transplant. We have a cobbled-together system of OPOs and couriers and private aircraft and commercial aircraft.”

In recent years, several courier companies have emerged to meet the market for transplant organs. Don Jones, chief executive of the Nationwide Organ Recovery Transport Alliance, or NORA, contracts with more than 15 OPOs and oversees about 400 organs a year on commercial flights.

“I would say 99.8% of our transports on commercial airlines go perfectly fine,” Jones said based on his estimate. Jones noted that his firm ships organs only on direct flights and uses GPS tracking to monitor them.

Some couriers and airlines use it; many don’t. Many OPOs monitor organs through a combination of verbal handoffs, automation and label scans, Brown said.

In Ginny McBride’s misadventure last fall, she contracted with a courier, Sterling Global Aviation Logistics, which used Delta Air Lines to ship the kidney.

Delta uses GPS trackers on its Dash Critical shipments, promising fast, guaranteed delivery of human organs. But on that night in October, the kidney was shipped from Orlando to Atlanta without a GPS tracker. In Atlanta, a cargo worker couldn’t find a GPS device to put on the box containing the kidney, so the worker held the organ for a later flight. That would have pushed it far beyond the window of viability.

An internal Delta report, obtained by McBride, found that Delta didn’t have enough GPS devices available in Atlanta that night. “Destination stations are not returning the devices in a timely manner,” according to the report. “One way to mitigate this from reoccurring is to have a larger inventory of GPS devises (sic) at each station.”

Delta declined to comment on the report.

alarm clock on a pink and blue background

Average national wait times for a kidney transplant vary widely.


The average wait time for a kidney varies widely nationwide, from less than three years to more than a decade. One proposal to put more organs to use called for eliminating the 58 donation service areas and 11 regions now used to allocate kidneys and replacing them with a zone of up to 500 nautical miles from the donor hospital.

In December, OPTN cut that range in half — to 250 nautical miles — in part because of an outcry about problems shipping kidneys via commercial air.

“There are certainly no technological barriers to doing GPS and to actually requiring it,” Brown said.

A UNOS committee is considering whether to collect data on transportation methods and outcomes, but, so far, the question remains under review.

“If the community wants it, they should ask for it,” Brown said. “We can help facilitate and get it done for them.”

McBride, who discussed solutions with her colleagues, hopes the transplant organizations will come together to solve transportation problems, to make sure every eligible donated kidney gets transplanted.

“Any organ that’s wasted, in my opinion, is a loss to the patient and to the community,” said Paul Conway, of the American Association of Kidney Patients, an advocacy group, who is himself a kidney recipient. “With all of the advances going on with drugs, with medical procedures, how can you have a logistics error be the barrier?”

Forest fires are good for bee populations

Fire serves a vital role in our ecosystem. Forest managers often prescribe burns also called a "controlled" burn to mimic the natural fires in forests and grasslands that may stimulate germination, reveal minerals in the soil, and increase seed vitality. Prescribed burns are performed by highly-trained individuals to accelerate growth in the ecosystem. Certain tree species like lodgepole pine, ponderosa pine, and the famous sequoia actually require fire to open their pinecones and release their seeds.

But do these burns help pollinators? A recent study from researchers at North Carolina State University examined the impact of prescribed burns on the native bee community in the Sandhills area of North Carolina. Bees are important insect pollinators of grasslands that depend on natural fire for ecological production. But fire destroys and removes flowering plants visited by bees. So how could fire help bees?

The study involved taking diversity counts that is, placing traps to catch bees and identifying them at the species level at sites that had been burned within two years and sites that hadn't been burned. 

The researchers found there were 2.3 times more bees captured in more recently burned forest sites than in the unburned sites.

Researchers found there were more flowering plants at recently burned sites, increasing the diversity of flowers known to benefit bees. Burns were conducted during the winter season, so as not to burn up woody debris that may serve as bee over-wintering habitat. 

Forest ecosystems that require fire for growth are found across the country. Fire benefits forest and prairie ecosystems by stimulated tree growth and increasing the diversity and presence of native plants such as Echinacea, providing food sources for bee species. Prescribed burns are a powerful tool for land managers, and this study is one of a growing number aiming to show the benefits of prescribed burns for bees. 

A prescribed burn at Yellowstone NP

A prescribed burn at Yellowstone NP

Your clothes might soon contain tiny generators to charge your electronics

Imagine never having to charge your Fitbit or Apple Watch. How cool would that be? Except that it wouldn’t be, because the energy for charging your wearable device would come from your body heat (Ed: Ba-dum-tsh). This is exactly what a group of researchers from Northwestern University and Donghua University in China have achieved by creating the first ever working, wearable thermoelectric generators (TEGs). They recently published their findings in the journal Nature Communications

Research on wearable TEGs has been underway for about a decade, although existing prototypes need to be perfected for practical use. Fundamentally, TEGs are made up of a conducting polymer, such as carbon nanotubes, and are able to convert absorbed heat into electric energy which then fuels battery power. But the currently available designs are too bulky to be integrated into fabric.

The scientists behind this new breakthrough generated TEG models using a special type of carbon nanotube fibers that's as thin and flexible as thread and could be woven into a fabric. Their TEGs have amazing stretch capabilities, capturing adequate thermal energy because they are aligned with the direction of heat flow from the body to the device. Lastly, their new TEG was able to transform this heat into battery power efficiently without being hampered by bodily movements. It showed a power density of 70 milliwatts per square meter for a 44 Kelvin temperature difference, one of the highest power outputs reported yet.

Tapping on keys, achieving steps and exercise goals all cause an increase in body heat. That day isn’t far when, the more we use our devices the more charged they will be. Until then, don’t forget your charging cords!

wearable tech

person's wrist with an apple watch

When winter no longer comes, what will the North look like?

Climate change is reshaping winters in North America. Across the region, temperatures have risen, snowfall and ice have declined, and the ecosystems and traditions of northern communities are increasingly at risk. The predictions for the next decades are even more alarming.

Environmental scientist Alix Contosta of the University of New Hampshire calls winter – defined as sustained temperatures below zero, snow cover, and ecological process that effect the social and economic systems – the underdog season. “Snow makes everything clean bright and new in winter," she says. "Winter without snow is dull, drab and brown and not fun." 

States in the northeastern U.S., from Minnesota to Maine, are shaped by a temperate climate. And they are well-known for their winter weather culture, fueling a robust skiing and tourism industry across the region, as well as important economies like maple sugaring and small-scale logging.

A chairlift at a mountain ski resort, Okutone ski resort.

Chairlift at a ski resort. Will skiing have to shift to the Western United States?


A recent study, published in the journal Ecological Applications, by a team of interdisciplinary natural and social scientists, suggests that winter as we know it is changing in the Northeast — with large ramifications on the region's season-dependent industries.

The study, a collaboration between scientists in the United States and Canada, compiled 100 years of meteorological data, with datasets ranging from 1870 to 2015. The data tracked winter weather events and seasonal fluctuations that define forest health, such as the amount of snow, temperature patterns, and stream water quality. They also examined data for ice days, frost days, and thaw days, as well as snowpack, snowfall, and snow depth. They then studied how these meteorological changes have impacted, and will continue to impact, key northern industries like maple sugaring and skiing that depend on cold days and nights and abundant snow.

One hundred years of precipitation and temperature data from weather stations across the study region constructed the backbone of climate data, alongside snow depth and snowfall events. Within the dataset, the researchers defined winter as November 1 through May 31 to capture the full range of winter events that define the ways that winter is changing, including how winter is starting later and ending earlier.

"Many people don’t realize how vital cold temps and snow are to the economy of the northern forest," said Contosta who led the new research.

The scientists were able to determine the degree to which winter was changing in the Northeast, finding that the frequency of frost, ice, and extreme cold days have decreased over time, while snow cover days have also waned. Days with snow cover have declined 1 to 2 days per decade. Coldness, or the combination of frost days, ice days, and extreme cold, declined at more than half of the monitored stations. Frost days, specifically, decreased at nearly all sites, declining about 1.1 days per decade, with variation from region to region, the study found.

These changes come with serious implications for the traditions at home in northern areas. Maple syrup production, for example, is highest in eastern Canada and the U.S. Northeast, with Quebec producing about 8 million gallons a year, followed by Vermont at about 1 million gallons.

Dipping a pipette into freshly made maple syrup.

Making maple syrup.

"Almost Done Making Maple Syrup by QuintanaRoo

Tapping season occurs from January through May, when temperatures are below freezing at night and above 40 degrees Fahrenheit in the day. This pattern, referred to as freeze-thaw days, is when the sap runs from the xylem, a tree's water transport system, through holes in the bark. Fewer freezing nights are predicted to change when maple sugar producers can tap their trees, potentially leading to less syrup availability.

The study found a decrease in the number of frost days and an increase in thaw days, supporting previous studies that indicated the freeze-thaw relationship was shifting due to climate change. Tapping used to occur in late February to early March in New England. Now, its creeping towards mid-February. Previous research has predicted that in 100 years, the tapping day tradition could occur as early as December

Snowpack acts as a buffer between the cold temperatures and the roots of a tree. Less snowpack means more frost deeper in the soil, hitting the roots and damaging their ability to uptake nutrients. For some tree species, like the sugar maple, less snowpack has been tied to slower growth over time.

The snow buffer extends to small-scale logging too. Logging originally occurred in winter as farmers finally had the time for the extensive work. Winter conditions are also beneficial for the soils, with snow cover protecting soil and roots from damage while heavy machinery is in use. Less snow could ultimately impact forest products and markets in the northeast, the scientists concluded.

Each year, 13.3 million people flock to ski resorts across the Northeast, expecting snow in abundance. Between 1999 and 2010, a lack of snowfall cost the skiing industry $1 billion, and it’s predicted that by 2040, southern New England ski resorts will no longer have the conditions to support alpine skiing. Snow can be made at 28 degrees Fahrenheit, and the new research by Contosta and her colleagues found 1- to 2.5-day decrease in the number of days conducive to snow making before December, contributing to delays in resort opening days.

Projections for winter in the next decades forecast trading snow for rain and above-freezing temperatures. The effects on ecosystems, industry and culture remain unknown – innovation can only go so far, the article warns, before the climate renders winter traditions impossible

“The loss of winter is how people in New England are experiencing climate change on the ground right now,” says Contosta, “This is something happening in our backyards”.

Olivia Box studies

Natural Resources and Forest Ecology


University of Vermont


A dog looking back at a group of people snowshoeing. Also maybe skiing.

Mars is hiding behind the Moon this morning

Occlusions are any kind of blocking off. If I step in front of you in line at the coffee shop, I have occluded you and also been a jerk. Go ahead, kick me in the shin. 

This morning, the Moon is stepping in front of Mars. This occlusion, Mars-and-the-Moon, occurs twice a year. It's kind of like an eclipse, but an eclipse is a specific kind of occlusion where a shadow is cast. But here there's no shadow. Just Mars briefly hidden behind the Moon's back.

You'll be in the best position to see the end of the occlusion in the Pacific time zone. With a clear low view in the southeast, you'll see Mars pop back out from behind the Moon's back. 

Enjoy the trip Mars.

A reconstructed picture of Mars, taken by a Viking orbiter, 1980.

Think mosquitoes only drink blood? Think again.

When we think of mosquitoes, we usually think of itchy bites and diseases like malaria or Zika. While they do feed on human and animal blood, mosquitoes are much like many other insects — they also use the sugar in nectar for energy for reproduction, movement, and survival. 

Mosquito on purple flower

k yamada via Flickr

A study by researchers at the University of Washington has identified the floral cues — or unique scents that attract different pollinator species — that influence mosquito visitation to a flower. The lab found that a specific scent produced by Platanthera obtusata, the blunt-leaved bog orchid, attracts the Aedes mosquito. Scientists observed the feeding behavior of mosquitoes on orchid flowers, and analyzed the compounds of the orchid's scent using mass spectrometry — a process which can identify chemical compounds based on the molecule's mass and chemical structure.

Mosquitoes feed on a wide variety of flowering plants, and in some cases even perform pollination while in search of nectar sources in the depths of flowers for sugar feeding.

The Platanthera orchids produced a distinct pattern of specific compounds, which are recognized and used by mosquitoes to distinguish between Platanthera and other species of orchids. The scent profile of Platanthera orchids and other mosquito-pollinated flowers were similar, taking science a step toward understanding why mosquitoes are more likely to pollinate one species over another. 

By understanding the olfactory cues used by insects like mosquitoes, researchers can better understand the impact that smell has on the allure of mosquito prey, such as humans. Manipulation of mosquito senses serves a large role in mosquito bite prevention, and will play an important role in our future goal to eradicate mosquito-borne diseases.

Artificial lights are disrupting firefly mating, putting them on the road to extinction

On a summer evening in the Smoky Mountains, photographer Radim Schreiber, is standing in a forest. Wind is rustling the leaves. As dusk sets in, he looks through the trees and sees amazing flying specks of light – a wild, fairy glow.

He's looking at fireflies, also known as lightning bugs. But fireflies may be in trouble because of, ironically, light itself.

According to a 2019 study, artificial light impacts fireflies in a big way. Fireflies find mates through a courtship process that involves flashing their "lights." And not just any light: the courting process involves a series of flashes, which are unique to each male and female. Females will choose their mate based on their unique flashing patterns. The females, in turn, will start a flashing "dialogue" with the mate of their choosing. It's an amazing sight to see.

So how does this courtship process clash with the lights we keep on at night? Fireflies rely on light to communicate, which has led scientists to wonder if light pollution impacts them in some way. Prior studies by the researchers confirmed this, as well as a substantial body of research. So the next logical question, and the one that the researchers tackled, was how this lighting impacts fireflies at the most basic level: courtship.

To measure and investigate how attracted fireflies were to artificial light, Ariel Firebaugh and Kyle Haynes, two scientists based at the University of Virginia, set up 15 pairs of white tarps outside at the Blandy Experimental Farm. One tarp in each pair was illuminated by an LED light, while the other, located 10m (~32 ft) away, was left in the dark.

The researchers then watched the courtship "flashings" of stationary females and free-flying males in Photuris (predator) and Photinus (prey) fireflies. In the wild, females sit stationary on a plant while the males fly around and flash their lights. To replicate this while disturbing the process as little as possible, a nylon-mesh container is placed on top of females as they perch on grasses.

Mesocosms come in all different shapes and sizes. This is an example of a mesocosm made from cattle tanks. 


Finally, to look more closely at how lights affected mating success, Firebaugh and Haynes used mesocosms (an experimental tool where natural conditions are replicated in a controlled environment) consisting of mesh sided canopies. These mesocosm canopies looked much like a pop-up canopy tent, but with mesh screen sides. To find mating behavior, the fireflies are marked with a fluorescent powder. After the trial was over, they are collected and observed for signs of mating: male-colored powder on female reproductive organs. 

In these lighted zones, the fireflies were less likely to engage in courtship flashes, and mating success was reduced. The researchers also investigated whether light pollution affected predator-prey relationships, but no significant impact was found.

Outdoor LED lighting spaces, like the one used in this study, can also act as demographic traps, say the researchers. That means that immigration (or the amount of fireflies coming into the area) far exceeds emigration (the amount of fireflies leaving the area) – meaning that fireflies, barring other circumstances, will stay in the lit areas. While the fireflies may be loving the bright LED lights, the lighting affects courtship behaviors, which are significantly reduced, and also likely reduces mating success.

A male and female firefly mate.

 Radim Schreiber 

Fireflies are attracted to light but this light "sucks" them in. It's like how a warm, cozy house is where you want to be on a cold winter day. It attracts you and you don't want to leave. In the same way, fireflies are attracted to our bright LEDs and don't want to leave the light. More fireflies enter the area, and then leave. They are attracted to it like a trap. But, like how it's not healthy for us to stay home all the time, it's not healthy for fireflies to stay attracted to this light. Fireflies rely on ambient light cues to know when to start courtship flashing, but when the environment is always lit, there is a problem. Courtship behaviors go down and breeding success is also likely to go down.

For Schreiber, a photographer specializing in fireflies, their significance transcends the food chain into that of cultural importance: "Often people have very joyful memories [about fireflies] from childhood, and when these experiences are being shared across people from different nations, they may feel that these experiences are more important than other differences we may have."

A firefly is seen against a full moon.

Radim Schreiber

Schreiber is now on a mission to capture the beauty of fireflies – before they disappear forever. He said, via email, that "There are unique and beautiful species of fireflies that live in very small areas, and when they lose their habitat, we may not see these fireflies ever again. I have been recording some of these species on camera with the idea of preserving them at least on video."

This is a huge problem – light pollution is one of the fastest growing types of environmental degradationand more than 99 percent of people living in America and Europe don't experience a "natural" night sky. 

As urban areas continue to grow, this problem will only get worse. In early February, researchers at Tufts University released a study pegging light pollution as the second most serious threat to fireflies, according to a survey of 49 experts across the world. Only habitat loss is more dangerous.

Anthony Warmack studies

Environmental Science


Oregon State University


Firefly on leaf

Iron concentrations in teenagers' brains can be linked to their cognitive abilities

You might have heard of iron deficiency anemia. Iron is the central element in hemoglobin, the oxygen-carrying protein of our blood. Having low concentrations of iron can lead to not having a proper circulation of oxygen, which usually translates to feeling tired or weak. However, there is also iron stored in tissues, including the brain. There, it helps with the cell’s production of energy, with the formation of myelin (i.e. white matter), and it is used by different enzymes that produce neurotransmitters. 

Much like everything brain-related, the concentration of tissue iron in the central nervous system needs to stay in a perfect balance. Too much iron might lead to an increased chance of neurodegeneration, too little iron might cause irreversible changes in brain chemistry. But what was previously unknown was whether teenagers were particularly susceptible to iron deficiency, as much as babies and children can be. A group of scientists from the University of Pennsylvania has now shown that there is a correlation between brain tissue iron during adolescence with cognitive abilities.

Bart Larsen and their colleagues analyzed brain scans of 922 humans (8-26 years old). Using a technique called R2* relaxometry, they were able to quantify the concentration of iron in the brain by magnetic resonance. This concentration, especially in a brain region called basal ganglia increased over time in all samples. However, there were some observed sex differences, with women's brains reaching a peak of iron concentration earlier. By doing a battery of neurocognitive tests, the researchers found that there was a correlation between how much iron was being accumulated over time with a person's cognitive performance. 

Although only a correlation, studies like this are important in finding how different external factors affect our development. Worth pointing out: iron deficiency is still a problem in the US affecting 15% of women and 3% of men. With this new study, we are more aware of the importance of iron in the normal brain development of teenagers.

person holding backpack

the lower half of a person holding a black backpack

On #WorldPangolinDay, we celebrate this roly-poly scaly anteater, one of the world's most trafficked mammals

Today is the World Pangolin Day. This day is celebrated each year, on the third Saturday of February, to raise awareness about pangolins. But this year, the ninth World Pangolin Day might have a different focus, given that a link has recently been suggested between pangolins and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which originated in Wuhan, China. However, we cannot blame the spread of this coronavirus on the pangolin, even if they do turn out to be the carriers.

Pangolins are mammals ranging in size from about a foot to over three feet. There are eight species of pangolin in the world, all covered in scales made of keratin, the protein that also makes up our hair and nails. They eat insects, including ants and termites, which has earned them the name scaly anteater. 

A pangolin

By Adam Tusk on Flickr

Sadly, pangolins face the risk of extinction in the wild, mainly caused by humans trafficking pangolins for their meat and their scales. In fact, they are among the most trafficked wild mammals in the world.

If pangolins do carry the SARS-CoV-2, which has not yet been conclusively proven, the spread was likely only possible due to this trafficking. Generally speaking, pangolins like to keep to themselves and are mostly nocturnal, so they do not often come into contact with humans naturally, unless we go out looking for them.

“I think that given the difficulty in monitoring the populations of all pangolin species, it is difficult to ascertain how well they are doing,” says Daniel Ingram, a researcher from the University of Stirling. The different species have different lifestyles — some live in trees, while others are ground-dwelling — which means that scientists need to develop different methods to monitor them.

“Understanding the behaviour of wild pangolins better could play a role in pangolin conservation, as it could help improve monitoring methods and help us understand how pangolins respond to human disturbances,” says Ingram.

And it seems like this is even more important if pangolins do turn out to be the SARS-CoV-2 carrier.


Scientists analyze centuries-old DNA to investigate French revolutionary's mysterious skin condition

Jean-Paul Marat (1743-1793) was a French journalist, politician, physician, and scientist during the French Revolution, who was assassinated while taking a medicinal bath for his worsening skin condition. While the manner of Marat's death is obvious, the cause of his worsening health in his final years has remained a mystery, with doctors hypothesizing that conditions such as scabies, syphilis or atopic eczema may have been to blame. Now, scientists have analyzed DNA from his blood stains to shed some light on this issue.

During his life, Marat was a French revolutionary who advocated for the rights of the sans-culottes (the poorest members of society), but also served as a court doctor, published findings on fire, electricity, and light, and wrote a regular periodical, titled L'Ami du peuple (The Friend of the People). At the time of his assassination, Marat was annotating two L'Ami du peuple issues in his bath. These blood-stained issues (made of old cellulose paper) were later donated to the Département des Estampes, Bibliothèque National de France, offering a rare opportunity for scientists to use DNA sequencing to posthumously diagnose infections in a historical figure. 

La Mort de Marat (Death of Marat) by Jacques-Louis David

In this study, Toni de-Dois and their fellow researchers took two non-destructive forensic swabs — one of a blood stain, and a second from an area of L'Ami du peuple with no blood stains for comparison. Following DNA extraction and sequencing, the researchers compared the two swab samples to account for any contamination that may have occurred in the last 200 years or so, before carrying out a number of analyses to better understand Marat's health at the time of his death.

Instead, researchers found DNA fragments matching Malassezia restricta, which is a fungal pathogen that causes seborrheic dermatitis (a chronic form of eczema). They also noted the presence of DNA fragments matching Cutibacterium acnes (although common, it is linked to acne) and Staphylococcus aureus (often detected in atopic dermatitis, though found in low quantities in Marat).

So what does this all mean?

Although de-Dois and their fellow researchers were unable to reach a specific diagnosis, they do provide evidence that Marat was suffering from an advanced fungal infection, likely seborrheic dermatitis, with additional bacterial infections. This study also happens to be one of the first to leverage DNA sequencing technology to diagnose infections in historical figures.

To find the exact answer to the mystery Marat's worsening health, researchers will need to analyze more of the DNA found on Marat's preserved possessions — with the potential to apply this analysis to additional historical figures.

Buy your scientist Valentine books from our reading list

We asked consortium members what they are reading, and wow, they really came through! Here are a few of the health-related books they recommend. Just so you know,  Massive may collect a percentage of sales from the links on this page. 

The Mystery of the Exploding Teeth: And Other Curiosities from the History of Medicine, by Thomas Moore

Buy the book: Amazon, Independent Bookstores

I think it goes without saying that I was drawn to the book because of the title. The book does a great job of explaining medical mishaps in an accessible and fun, but respectful, way. I can’t help but draw parallels between some of the historically-used remedies (e.g., wine enemas) and what some people do now (e.g., coffee enemas) - Monica Javidnia

The Collected Schizophrenias by Esmé Weijun Wang

Buy the book: Independent Bookstores, Amazon

In her essay collection, Esmé Wang describes her journey being diagnosed with bipolar disorder and subsequently after with schizoaffective disorder. I really enjoyed that the essays explored different aspects of the disease that I was unaware of such as involuntary hospitalization, mental illness stigma, and the history of the disease itself. While I was reading the essays, it became apparent how courageous the author is to share her life experiences and I think these essays will shed light on the disease and the stigma that surrounds it. - Felicia Davatolhagh

Doing Harm: The Truth About How Bad Medicine and Lazy Science Leave Women Dismissed, Misdiagnosed, and Sick by Maya Dusenbery

Buy the book: Amazon, Independent Bookstores

Inspired by her own difficult experience with getting a diagnosis of rheumatoid arthritis, Dusenbery presents a really compelling look at gender bias in medicine that left me frustrated with the status quo. She covers the origins and outcomes of this bias, including historical medical practices (ugh, “hysteria”), basic biomedical research, the inclusion (well, lack of) women and minority communities in clinical trials, and interactions with clinicians. I hope this inspires people in the biomedical community to do better. - Rachel Stewart

Books about science and sex

I'm currently reading Bonk: The Curious Coupling Of Science And Sex by Mary Roach, after I have read The Technology of Orgasm: “Hysteria,” the Vibrator, and Women’s Sexual Satisfaction by Rachel Maines. I am thinking of writing a book review on these two books! - Crystal Chan

A painting of a woman sitting on a deck reading a book.

Climate change in the Arctic has ripple effects for all life on Earth

If you’ve been in the Northern Hemisphere lately, you have probably experienced some extreme weather. From extreme cold and snowy snaps to deadly heat waves, droughts, and flooding, the weather in the north feels more intense and variable than ever. This winter, for example, northern countries have been posting their warmest winter temperatures on record  —  from the United States to Finland, this winter has been abnormally mild. Even Antarctica has hit its warmest recorded temperature this season!

Warm winters aren't the only weather weirdness we've experienced more often. Over the past decade, extreme weather events have made headlines all over the world: the midwestern Polar Vortex and Snowmageddon in Washington, D.C., Pacific Northwestern and European heatwaves, flooding in the Midwest and south Asia, droughts in California, high-intensity hurricanes in the North Atlantic… the list seemingly goes on and on. 

To better understand what’s happening with the weather in the US and Europe, climate scientists have been looking a little farther north. They have been tracking Arctic warming and sea ice loss for decades, noting correlations between high-latitude warming and extreme weather events at lower latitudes. A recent article in Science Advances reviewed, in depressing detail, the most alarming changes that sensitive Arctic regions are undergoing as a result of climate change. The Arctic is warming at a faster rate than the rest of the world, resulting in less sea ice, early snowmelts, and melting permafrost that releases greenhouse gases. The shifts in Arctic climate are dramatic, and their effects are not limited to the Arctic. 

Extreme weather events in the midlatitudes (roughly from the top of Florida to the southern tip of Greenland) – including heatwaves, flooding, and cold snaps –have been linked to the Arctic’s rapid warming and sea ice loss through changes in atmospheric circulation patterns. These patterns (the way in which air masses move through the atmosphere) depend on a number of factors, but are mostly controlled by two fundamentals of physics: temperature and pressure. Temperatures in the troposphere – where weather happens, the lowest level of the atmosphere, from the ground up to about 15 kilometers – affect the stratosphere, the middle layer, about 15-50 km up, and vice versa, because air pressure and density depend on temperature. Warm air rises and cold, dense air sinks; the bigger the temperature difference between two air masses, the bigger the energy imbalance is. Those temperature and pressure imbalances drive air circulation and wind. 

Arctic warming can also affect the jet stream, a fast west-to-east flow of air that hovers high in the troposphere, by weakening it and causing it to meander. That meandering can be compounded by a phenomenon known as Rossby waves, wavy atmospheric patterns that encircle the middle of the northern hemisphere. Picture a cosine wave stretching from Seattle to St. Louis to Buffalo, then curving into the Atlantic. They form because the sun heats the planet unevenly; landmasses of different sizes and oceans absorb heat differently, creating an energy imbalance. Air masses flow around the planet, transferring heat. As the air masses flow, they form wavelike patterns with peaks and troughs that progress, slowly, from west to east.

The shape and movement of Rossby waves depend on temperature and pressure gradients throughout the atmosphere, which can be affected by – you guessed it – long-term Arctic temperatures. When these waves stretch farther south, they also tend to move eastward more slowly, letting weather conditions linger over midlatitudes longer than they might otherwise. The longer weather conditions linger, the more likely extreme weather events are. That’s when we experience dangerous heatwaves and apocalyptic snowstorms. Or, as much of the eastern and midwestern US has experienced so far this season, the Rossby waves can linger higher up (say, above Ontario instead of Ohio), creating an unusually mild winter for us. This effect can be amplified during an El Niño year, when ocean surface temperatures in the eastern Pacific are warmer than usual and weather patterns across the U.S. change. 

Beyond having to pull out our warmest parka or pay an exorbitant heating bill, the extreme weather events linked to Arctic warming have a variety of negative effects on people. If a heat wave hits, especially in a region ill-prepared to cope with it – like where people tend not to have air conditioning, for example, or with a large elderly population – the risk of loss of life is high. In a “business as usual” emissions scenario as outlined by the International Panel on Climate Change, where we don't alter our rate of greenhouse gas emissions, at least twice as many heat-related deaths are likely to occur in U.S. cities than under a lower-emissions scenario. The "urban heat island" effect, where cities are hotter than surrounding rural areas, can exacerbate heat waves and increase mortality rates.

arctic fox sitting on snow

The changing Arctic threatens plants, animals, and humans alike — no matter how cute

Photo by Jonatan Pie on Unsplash

Along with all of these ill-effects come a suite of ecological changes. As temperatures warm, climate patterns are essentially shifting northward – which is why vintners in France are panicking and trying to adapt, and those in England are eyeing a prosperous future their current climate doesn’t allow. Bees are suffering in heat waves., with potential ramifications for agriculture. In the southeastern US, an invasive, rapidly-spreading leafy vine called kudzu has been spreading for decades, choking out forests. In the Arctic, as warming changes environments, the ranges of both plants and animals may grow or shrink, and the spread of diseases may threaten local populations. Antarctica, which hosts unique ecological communities, may be subject to invasive species as it becomes more habitable. Worldwide, as climate change drives ecosystem shifts, plants, animals, and people will be forced to respond. Some will survive. Others won't.

The question of what the consequences of extreme weather events will be is complicated to answer. There are no one-size-fits-all answers in climate change. What we do know is that if we maintain our business-as-usual approach to greenhouse gas and aerosol emissions, extreme weather events will likely become more intense, more frequent, and harder to predict – as will the economic consequences.

Rebecca Dzombak studies



University of Michigan


arctic warming and people

two people standing on a sea of cracked ice

The science behind Nike's Vaporfly shoes

On January 31st, World Athletics released new technical rules officially qualifying what a 'legal' running shoe is. A host of brands, led by Nike with its Vaporfly series, have forced the hand of the regulatory agency by developing shoes containing new types of lightweight foam and shock-absorbing carbon plates that function like springs. These types of shoes have been proven in studies to improve running economy over conventional marathon racing shoes. 

Because Nike has led the development of these shoes, their sponsored runners have enjoyed a relative advantage over their competitors dating back to the 2016 Olympic Trials, where 4th place finisher (Sketchers-sponsored) Kara Goucher compared the Vaporfly shoes to a doping advantage. Distance-running scientists weighed in on the resulting kerfuffle, proposing limits on sole height to future-proof the stacking of carbon plates resulting in bigger and bigger springs. 

World Athletics modifies rules governing competition shoes for elite athletes.

Details here: https://t.co/IA021EQfzR pic.twitter.com/9k0zgnf8Un

— World Athletics (@WorldAthletics) January 31, 2020

It appears that World Athletics agrees: they've ruled that no more prototypes are allowed in competition; shoes must have a maximum sole height of 40 millimeters; and they may have no more than a single carbon plate. Those rules allow runners to wear Nike's popular Vaporfly 4% and Next% (pictured) shoes, but it appeared they would ban their Alphafly shoe, last year's prototype worn by both Eliud Kipchoge (1:59:40) and Brigid Kosgei  (2:14:04) when they shattered record marathon times in Vienna and Chicago. However, upon official measurement the Alphafly just barely cleared the height limitation at 39.5 millimeters. 

Shoe brands will continue to innovate with new materials and designs, but whether they manufacture exclusively within those limits from a commercial aspect remains to be seen: is there a market for shoes that may not be competition-legal, but that could allow amateur athletes to reach the performance levels of more gifted athletes? That is a question that science cannot answer.

photos of bright pink and green running shoes

Don't worry, moderate drinking probably isn't shrinking your brain

Alcohol is one of the most widely used and abused drugs on the planet. It's important for us to understand how it is, or is not, affecting our bodies and our health. There are countless studies linking alcohol and health – from how a small amount of red wine may be good for your heart, to how moderate drinking may help protect against dementia – but the problem is that correlation doesn't always imply causation. 

As a PhD student, I wondered, could I test the popular claim that moderate alcohol use shrinks people’s brains? This is actually quite tricky. In animals, we can design sophisticated experiments to ask "does x cause y?" kinds of questions, but these are often impossible in humans. We can do a randomized controlled trial to test whether a new treatment works better than a current treatment, but the opposite, testing whether a treatment or drug is harmful, is highly unethical and out of the question.

twins Mark and Scott Kelly

US astronauts and identical twins, Mark and Scott Kelly, have participated in a twin study to determine how space flight impacts the human body

NASA/Robert Markowitz on Wikimedia Commons

What other options are there? One of the most powerful approaches in humans is to study twins and siblings. Twins and their siblings share many of the factors that can complicate or mask causation in standard studies. They have very similar or nearly identical genetics, their early life experiences were probably almost the same, they were likely raised in the same house and had similar nutrition, the list goes on. If one twin behaves differently (for instance if one drinks a lot and the other hardly at all) and the twins also differ on the outcome we’re interested in (in my research, brain volume), then that provides evidence that there might be a causal effect. By using twins and their siblings, human disease researchers can account for all kinds of alternative explanations for why people have the illnesses that they do. 

So, that's what we did. First, my colleagues and I examined a group of over 1,300 college-aged adults and found several parts of the brain that were smaller in people who drank more. I then conducted an analysis on a second data set with adult twins and their siblings (over 800 of them), looking at alcohol consumption and brain volume, and did not find any evidence of a causal effect. Twins didn’t differ in their brain volume, regardless of how much they drank. This, and some other analyses, suggested that there are separate genetic factors that drive both reduced brain volume and increased alcohol consumption. 

Moderate alcohol consumption, it turns out, doesn’t shrink people’s brains. Instead, people with brains that are a little smaller than average in a couple places are likely to drink slightly more than people with average sized-brains. In genetics we call this a "predispositional" effect, because brain volume is a marker for a genetic predisposition to drinking alcohol (brain size, by the way, is not strongly correlated with intelligence, if you were wondering).  

My first analysis in one set of people saw evidence for a genetic effect, but is there any corroborating evidence? If brain volume indicates genetic predisposition towards drinking alcohol, then it should also predict a person’s future alcohol consumption. We analyzed a data set of children and adolescents whose brains were scanned before they’d ever drunk alcohol, and then reported their alcohol use over the next six years. We found that the sizes of some parts of their brains predicted the age at which they would go on to have their first full drink of alcohol. This suggests that brain structure truly is a marker of risk for alcohol consumption.

an image of the brain with an area in the center highlighted in red

The middle frontal gyrus (red) is one of the regions in the brain where a smaller size indicates a genetic predisposition towards drinking more alcohol 

Anatomography on Wikimedia Commons

But is this conclusion plausible? Is there any evidence that’s how biology actually works? To answer this, we turned to a data set of human gene expression, and found that genes that are associated with alcohol consumption are likely to be highly expressed in the human brain. Digging deeper, we identified genes that are expressed at different levels in the brain depending on a person’s genetic risk for alcohol use. We don’t know exactly what these genes do (which is not unusual, as there are thousands of genes), but we do know that they are probably important for brain development. Our results, recently published in the journal Biological Psychiatry, show that it is biologically plausible that alcohol genes also affect the brain. 

Some things remain unclear. We don’t know where the arrow of causality is pointing. Brain structure is a marker for genetic predisposition towards alcohol use, but that doesn’t mean that brain structure is causing people to drink more. It might be the case that changes to brain structure are part of the mechanism by which genetic risk affects how much a person drinks later in life, but we have no hard evidence one way or the other. 

There are also still lots of unanswered questions and several different directions for future research. An important one is figuring out how much alcohol it takes to actually start damaging the brain. We know that alcoholism, and probably even chronic binge drinking, damages the brain. But where is the boundary between moderate and heavy alcohol use, in terms of the impact on the brain? Another question is when associations between genetic risk for alcohol use and brain structure emerge. We know that the brain changes a lot over the course of human development – identifying when differences in brain structure arise could help point to the biological processes that are affected by a genetic risk for alcohol use. 

No matter the finding, it is important to remember that correlation isn’t causation. A correlation is the first hint at a possible causal relationship, but there are lots of alternative explanations out there for any connection we might observe. In the case of alcohol and the brain, my research found that there are genetic factors that influence both alcohol use and brain volume, resulting in a correlation between the two. This finding refines our understanding of the impact of alcohol use on human health, and helps to point the way to biological mechanisms that might be helpful for the treatment or prevention of substance use disorders in the future. 

David Baranger studies



University of Pittsburgh


woman drinking wine

side view of woman drinking a glass of wine

You can mimic the physics happening on the surface of the Sun in your kitchen

The images of the Sun recently obtained by the Daniel K. Inouye Telescope are stunning, but you don’t need a 4.24-meter telescope to see the physics first-hand.

Plasma heats within the Sun, becomes less dense, then rises to the Sun's surface. Once there, it cools, gets dense, and sinks again. The gorgeous “caramel popcorn” appearance is a result of the plasma becoming ordered into cells the size of Texas. The edges of these cells are defined by dark lines of sinking plasma. This is described by Rayleigh-Benard convection, which tells how the size of these regions depend on the properties like the temperature, density, and viscosity of the plasma, and how heat transfers through it.  

The same sort of convection that happens in your kitchen. You can observe this effect by mixing food coloring and dish soap, then placing it in a pan on the stove. Of course, your convection cells will be a bit smaller than those on the surface of the Sun!


rainbow colored image of convection happening in a household experiment

Did these scientists just create the first lab-grown human breastmilk?

Their press release was understated. “Two women may have made breastmilk — outside the body,” food scientist Michelle Egger and cell biologist Leila Strickland announced in a Medium post this past Thursday. The two founders of BIOMILQ presented the first evidence that they can grow breastmilk directly from isolated human mammary cells, housed in a sophisticated bioreactor. This may spell the beginning of the end for infant formula, and a new beginning for much other lactation research. 

The understatement—the may—was a sign of cautiousness. Strickland and Egger don’t want to make false promises. They haven’t created a full replacement for breastmilk yet, after all, just a cultured version that contains two of the major components of the original: lactose and casein. They take the presence of these two major components to mean that they are on the way to creating milk nutritionally equivalent to breastmilk. 

This is no small matter. Breastmilk is still widely considered the best way to feed babies, especially for the first six months of their lives, but many parents don’t have that option for a variety of personal and practical reasons. The popular alternative is infant formula, which has many benefits but can be a challenging adjustment for infants' digestive systems because it relies on non-human proteins, often from cows' milk but sometimes from hydrolyzed soy. BIOMILQ wants to become the next best thing when a newborn can’t be fed natural breastmilk—as digestible as human milk but as practical as infant formula.

Further tests are forthcoming, which could take the may out of the next announcement. However, BIOMILQ isn’t the only company working towards culture-based breastmilk. A day after their announcement, Singapore-based biotech start-up TurtleTree Labs announced that it would be presenting its own lab-grown mother’s milk to the public this spring. Other companies have announced similar ambitions. All the more reason for us to talk to these two vanguards of the cultured breastmilk revolution.

Since this is their first extensive interview, we wanted to know: how did they get involved with the mad plan to create breastmilk in a lab? How did they do it scientifically? Why do it anyway? And what hurdles do they perceive in future, translating their findings out of a lab context into a general available product?

Combining Forces

Egger and Strickland have been working together for just about half a year—they founded their company in September 2019—and, judging by the results, their collaboration has taken off like wildfire. They arrived at the same interest from different disciplines, but with similar convictions. Above all, they shared a desire to use their scientific knowledge to tangibly benefit people, and both of them had settled independently on helping them from the earliest possible age.

Egger is a food scientist by training and worked for a number of years at General Mills, where she invented new processing techniques and did consumer insight work, working on organic foods like the famous LÄRABARs. In this context, she developed an interest in the daily decisions mothers make about their child’s nutrition. This led to her starting an MBA at Duke University with an emphasis on social impact entrepreneurship, specifically food insecurity, malnutrition and global food systems. Last summer, she worked for the Bill and Melinda Gates Foundation, researching “affordable plant-based protein sources for low-and-middle-income countries,” which deepened her interest in early childhood nutrition.

“During that summer at the Gates Foundation, I realized that the age at which I really appreciate kids—at three years old, when they have more of a personality—it was too late to help them. If we want to help the world, if we want to see babies grow up to be healthy, strong, capable adults, we have to be there from the moment they're born. Breastmilk is a huge part of that.” That summer also exposed her to breastmilk substitutes, and the politics of formula suppliers, which she says, “value sales over the benefits of children.”

By the end of that summer, Egger felt deflated. “I realized that even the Gates Foundation, working with the largest multinationals in the world, couldn't move fast enough. The first 1000 days in a baby's life are so vitally important to set the nutrition fundamentals that they will carry on throughout the rest of their life, affecting all their cognitive and physical abilities. For every year or two that it took us longer to try to get a project moving, millions of children around the globe were falling behind.”  Egger knew breastmilk was the answer to setting every person on the right nutritional path, but it was also the problem. A new alternative to breastmilk was needed.

Strickland and Egger.


Serendipitously, this is precisely when she met her BIOMILQ co-founder Leila Strickland. The cellular biologist had been interested in growing breastmilk in a lab for some time, and had also arrived at this interest from a combination of professional and personal investments. After getting her postdoc at Stanford in cellular biology, Strickland had two children; both were born prematurely and she had trouble breastfeeding them. This kicked off a search for alternatives. She knew there had to be a better option.

She found inspiration in cellular agriculture. Seeing Mark Post serve the first lab-grown burger at a press conference in 2013 was one such milestone. “It was pretty groundbreaking just in terms of my own thinking about what we could use the stuff of cell culture to accomplish.” Strickland started working on technology to produce milk from cultured cells, with the help of her husband. She pursued this ambition “at times as a garage hobby, in the grand tradition of tinkering, and at times as a full-throttle, furious pursuit of nothing less than the betterment of our health and our planet.” 

Cellular agriculture non-profit New Harvest provided invaluable intellectual support. "They were really the first people who looked at us like we weren't crazy,” Strickland recalls a meeting in 2015. “They were excited about our work. We had a super-invigorating call with Isha [Datar], and then attended the first New Harvest conference. They've been such an important influence on the field, and we made good connections there. We've continued the conversation with them ever since." 

Back then, Strickland says, “everyone looked at me strangely when I told them what I was trying to do.” But that has turned in her favor. “Even out here in North Carolina today, people know about cellular agriculture and cultivated meats, and are starting to get really excited about the possibilities.” Sensing this new widespread interest, Strickland started looking for a business partner  to help her bring this technology into the world. “I met Michelle last summer, connected by a mutual friend in the area and in the field, and it's been a really just incredibly natural partnership ever since. Our two backgrounds were a bit like puzzle pieces coming together. She's been able to help accelerate this incredibly over the last few months and now we just feel like we're on a rocket.”

The Way Forward

The speed of their success is less surprising if one considers the amount of expertise each of them brought to the table. “We’ve known for decades that mammary cells can be grown easily outside the body,” Strickland says. “It's a common model system for breast cancer research. We also know a lot about the cells. We know that they'll produce the components of milk when grown in culture on a benchtop scale.” 

Aside from these basics, BIOMILQ is dedicated to solving an obvious but daunting problem: the cells are kept alive by a nutrient-dense liquid and, unless designed otherwise, would secrete the milk directly into it. “We needed a compartmentalizing process because we couldn’t serve people a mixture of milk and media. That’s been a guiding principle for our engineering.” That innovation, which separates them from other contenders in the field, is now patent-pending. “That was really the core insight from my background: understanding the process of secretion and how cells orchestrated spatially.”

For these initial results, they started working with commercially available cell lines, specialized human mammary cells that can grow indefinitely under the right conditions, and expanded it in culture, before inoculating it in a bioreactor. “That’s a process that takes a couple of weeks,” Strickland explains. “The cells continue to grow and divide as in any standard validation culture system. One of the things that's really beautiful about our product and our process is that we're really focused on nurturing the cells and growing the cells to perform their optimal function. We don't ever have to harvest our cells outside of this system. Our job is just to provide them the nutrients they need to do their jobs as well as they can. We're in the business of taking good care of cells.”

Proof of Concept

Their attempt to recreate breastmilk is based on an admiration of its natural biology. “The special thing about milk is its molecular complexity,” says Strickland. “It's got a constellation of components that all need to be there at optimal levels in order to support the growth of the human infant, as designed by 200 million years of evolutionary pressure. In order for something to be nutritionally equivalent, the complexity needs to resemble what we see in actual breastmilk.”

Bioreactor at work.

Wikipedia commons.

While their first proof-of-concepts highlight only two molecules in the myriad of nutrients, they see it as a sign that many more are there. “The reason that we think that our current findings represent an important milestone is because we've demonstrated the production of a predominant sugar and a predominant protein at the same time in the same system,” Strickland details. “I don't think it would be as exciting if we had only produced lactose or if we had only produced casein, but the fact that we produced them both is indicative that we've turned on multiple pathways required for milk biosynthesis.”

Moving forward, they plan to use more sophisticated methods to analyze their sample, like mass spectrometry, which will vaporize their milk and detect the masses and charges of all the individual components within the cellular product. “We expect to be starting to run some of those samples in the next couple of weeks,” Strickland explains. The two scientists will consider their proof of concept experiments complete when they can identify all the different sugars, proteins, and fats present in their milk. 

If the nutritional profile is as expected–equivalent or near-equivalent to natural breastmilk—scaling up will be the next step. Cell culture isn’t cheap, but BIOMILQ is confident about their economies of scale, especially since they’ve been using off-the-shelf components and cells so far. “We're using systems that are made to be used with all types of cells that are not specifically purpose-built for this use,” Strickland says. “And so we have a number of sort of customizations to explore in terms of their effects on optimizing this process. We have a lot of exciting ideas about how to upregulate the process of milk production.”

While their main goal is to recreate breastmilk in all its components, they will not be deterred if these initial samples have their own particular character. “One of our academic advisors who we spoke with about this was really optimistic about that exact possibility. He said that every failed experiment is a new product, because there might be babies out there who are allergic to that one component that you're missing. One thing that is worth noting is that milk itself is a really dynamic substance that just differs a lot from woman to woman, and from day to day, based on factors of her own biology. We expect that the nutrient content of our milk will fall within the range of what is observed in a normal population of breastmilk.”

The Next Steps

Egger and Strickland are excited about the potential research avenues opened up by their innovation. “We’re talking about a new way to grow mammary cells,” Strickland says. “It offers the possibility of studying lactation and human milk in a way that hasn't been available to the research community in the past.” With their system, they hope to both produce breastmilk alternatives and further our understanding of natural breastmilk production. “I think that mammary cell differentiation, milk production, milk composition changes over time are all really interesting research questions that can be addressed at a system level using our process." 

The next step for the product is animal trials, and then, eventually, human trials. As one may expect, trials with newborns present unique challenges. Luckily, the two scientists intend to start by doing safety work with adult populations. “We've been advised that folks who have compromised digestive functions or are immunocompromised could really benefit from drinking human milk as a source of nutrition with more bioavailable nutrients,” Strickland says. Other adult beneficiaries could be people who have trouble with their intestinal lining.

Mother breastfeeding her child in the Phillipines. 

Photo by Eibner Saliba on Unsplash.

These proposed adult uses of breastmilk are one of the reasons there’s such a large black market for it. “Currently, the only source of human milk is a lactating woman,” Strickland explains. “For the most part, babies need all of the human milk that lactating women produce. And so there's not really ever been an opportunity to evaluate the possibility of human milk as a nutrition source for people who are perhaps geriatric or immunocompromised or have to compromise digestive function.” While these studies will focus on safety for newborns, it may also have the bonus of expanding the populations they can help.

Aside from regulatory challenges, the decisive question is how to grow this breastmilk cost-effectively at a marketable scale. “We want to optimize the process and proceed to a place where we had a line of sight to scalability,” Egger says. “An exciting part of our technology is that our unit economics basis is not that far off from where we need to be in order for it to be affordable for a lot of moms.” BIOMILQ is currently looking to raise a seed round of funding to support these efforts.

Their current bioreactor contains approximately as many mammary cells as a human mammary gland, except these cells have a major key difference. “A lot of our ability to scale is going to revolve around the fact that there is a lot of negative regulation of lactation within the body because the body has to balance the compromise between the mother's needs and the baby's needs,” Egger says. “Milk production is actually shut down in the body most of the time so that the mother is not spending all of her energy to produce enough milk that will never be consumed. Since we only care about the needs of the cells, we can produce milk all the time. Cells don’t sleep.” 

Egger and Strickland do not see their product as a complete replacement of breastmilk. “We’re trying to be nutritionally on par with it,” Strickland says. “We don't intend to replicate the sort of immunological properties of breastmilk or at least immunoglobulin. Some of the microbiome that comes from maternal inference transfer during breastfeeding itself is not something that we that our products would replicate. Some advantages of actually feeding the baby on the breast are likely to remain. However, our product will be vastly nutritionally superior to infant formula and will offer women a way of feeding that's nutritionally much better for their babies and, and quite a bit more realistic for them.”

With all this excitement, it’s easy to get carried away, but Egger and Strickland are resisting that urge. “We want to be sure before we tell moms out there that we’ve made milk,” Egger explains, “We want to be sure the science is right.” As BIOMILQ accelerates towards their cell-based breast milk, it’s clear that these two scientists will make sure that mothers and newborns are in good hands with the best nutrition mother nature has to offer. Their outlook remains cautiously optimistic. “We hope,” Strickland says, “to make a bigger announcement soon.

Joshua Peters studies

Biological Engineering


Massachusetts Institute of Technology


To find its last reservoirs, people with HIV donate their bodies immediately after death

Anyone can be a science hero. Often, when we think of a science hero, a researcher, educator, doctor, nurse, or engineer comes to mind. But science heroes are also the individuals who aren't acknowledged in author lists on breakthrough papers, and are rarely highlighted in the media. In fact, some of these science heroes are the very same people who participate in clinical trials, willing to sacrifice everything for science, even after science has appeared to fail them.

A new study in the Journal of Clinical Investigation describes six such science heroes, known as “The Last Gift” cohort. The goal of this study was to enhance our understanding of HIV reservoirs, which refers to deep tissues where HIV hides even during treatment and remission. Fluids, like blood, transport HIV, where it is easily studied, but little is known about HIV in stationary reservoirs like the kidney, liver, and spleen.   

Understanding HIV dynamics, both where it travels and where it hides, is important in order to develop therapeutic approaches, but currently, the ability to investigate HIV reservoirs is only possible after death. By the time tissues are normally collected, the virus has generally degraded and further study is useless. 

This cohort consisted of six individuals with HIV, who were also diagnosed with a terminal illness from a non-HIV condition, such as cancer. As part of the cohort, they consented to not only blood sampling during their life, but also donated their bodies for rapid autopsy immediately after death. In this study, researchers conducting autopsies found HIV in every one of the 28 reservoirs they tested. This means that in order to completely eliminate HIV, researchers will need to target all of its hideouts in order to eliminate the virus.

The Last Gift is an extremely appropriate way to refer to these science heroes. Even with the knowledge that they had a fatal disease and would be unable to experience a more effective HIV treatment, they donated their bodies to science so that others might be able to benefit. It’s important to thank the thousands of science heroes who have and will make similar sacrifices, like The Last Gift cohort.

Two people holding hands.

Coffee baristas were right all along — grinding coffee finer doesn't always produce a stronger cup of espresso coffee

New research on the physics of espresso has generated a caffeine buzz in the news, but as a hipster, physicist, and a coffee snob, I feel obligated to contextualize these results. 

As my fellow coffee lovers may know, espresso is made by forcing water through a bed of coffee particles, which extracts chemicals like caffeine and sugars. Smaller particles and higher pressures usually mean higher extraction and stronger cups, but experienced baristas know that grinding coffee finer doesn’t always produce a stronger cup. Baristas have proposed empirical solutions, but only now have scientists, in collaboration with the coffee community, succeeded in quantifying this effect.

With a mathematical model backed by experiments, researchers finally confirmed the theory that baristas have held for years; that high pressure (often achieved by adding more or finer grounds) and irregular particle size can cause flow channels to form, resulting in uneven wetting of the coffee, and ultimately making a weaker, less tasty brew. 

Researchers hope this model helps make coffee more delicious with less waste — and the success of this work demonstrates the importance for clear science communication as fruitful collaborations can often be found outside academia.

coffee shop

view of a coffee shop from above

Your brain isn't the same in virtual reality as it is in the real world

Virtual Reality (VR) is not just for video games. Researchers use it in studies of brains from all kinds of animals: bees, fish, rats and, of course, humans. Sadly, this does not mean that the bees have a tiny VR headset. Instead, the setup often consists of either normal computer screens surrounding the subject, or a special cylindrical screen. This has become a powerful tool in neuroscience, because it has many advantages for researchers that allow them to answer new questions about the brain.

For one, the subject does not have to physically move for the world around them to change. This makes it easier to study the brain. Techniques such as functional magnetic resonance imaging (fMRI) can only be used on stationary subjects. With VR, researchers can ask people to navigate through a virtual world by pressing keys, while their head remains in the same place, which allows the researchers to image their brain.

A demonstration of a virtual environment used for testing brain-machine interfaced prosthetics.

VR has become a powerful tool in neuroscience.


The researchers can also control a virtual environment much more precisely than they can control the real world. They can put objects in the exact places they want, and they can even manipulate the environment during an experiment. For example, neuroscientists from Harvard University were able to change the effort the zebrafish had to put in to swim to travel the same distance in VR, which causes zebrafish to change how strongly they move their tails. Using this experiment, researchers determined which parts of the zebrafish brain are responsible for controlling their swimming behavior. They could have never performed such a manipulation in the real world.

If you've ever experienced VR, you know that it is still quite far from the real world. And this has consequences for how your brain responds to it.

One of the issues with VR is the limited number of senses it works on. Often the environment is only projected on a screen, giving visual input, without the subject getting any other inputs, such as touch or smell. For example, mice rely heavily on their whiskers when exploring an environment. In VR, their whiskers won't give them any input, because they won't be able to feel when they approach a wall or an object.

Mouse wearing a virtual reality headset

VR cannot replicate how mice rely on their whiskers to navigate.

Adapted from Pixabay by Dori Grijseels

Another issue is the lack of proprioception, the feedback you get from your body about the position of your limbs. Pressing a button to walk forward is not the same as actually moving your legs and walking around. Similarly, subjects won't have any input from their vestibular system, which is responsible for balance and spatial orientation. This is also the reason some people get motion sickness when they are wearing VR headsets.

When VR is used for animal studies, the animals are often "headfixed," meaning they cannot turn their head. This is needed to be able to use a microscope to look at the cells in their brain. However, it poses a problem, specifically for navigation, as animals use a special type of cell, called a "head direction cell," in navigation tasks. These cells track the orientation of the head of an animal. And when the mouse can't move its head, the head direction cells can't do their job.

This is especially the case for the cells in the hippocampus. That is the part of your brain that is responsible for navigation, and so, relies heavily on inputs that give you information about your location and your direction. 

Neurons talk to each other through electrical signals called action potentials, or spikes. The number of spikes per second, called the  "firing frequency," is an important measure of how much information is being sent between neurons. A 2015 study found that, in VR, the firing frequency of neurons in a mouse is reduced by over two thirds, meaning that the cells don't send as much information.

The same study also showed that the cells are less reliable. They specifically looked at place cells, cells that respond to a particular location in the environment and are incredibly important for navigation. In the real world, these cells send spikes about 80% of the times that the animal is in a particular location. However, in VR, this is reduced to about 30%, so when an animal visits a location ten times, the cells will send spikes during only three of those visits. This means the animals are not as sure about their exact location.

Another important feature of brain activity are brainwaves, or neural oscillations. These represent the overall activity of all the neurons in your brain, which goes up and down at a regular interval. Theta oscillations, brainwaves at a frequency of 4-7 Hz, play an important part in navigation. Interestingly, scientists found that rats have a lower frequency of their theta oscillations in VR compared to the real world. This effect on oscillations is not limited to navigation tasks, but was also found for humans who played golf in the real world and in VR. It is most likely caused by the lack of vestibular input, but scientists are still unsure of the consequences of such changes in frequency.

We know that we should be critical when interpreting results from neuroscience studies that use VR. Although VR is a great tool, it is far from perfect, and it affects the way our brain acts. We should not readily accept conclusions from VR studies, without first considering how the use of VR in that study may have affected those conclusions. Hopefully, as our methods get more sophisticated, the differences in brain activity between VR and the real world will also become smaller.

Dori Grijseels studies



University of Sussex


Person wearing a virtual reality headset

Wasps are parasitizing caterpillars less often under climate change

Assessing the impacts of climate change is essential for scientists who want to understand ecosystem dynamics. However, until recently, relatively few studies have linked climate variability to species interactions.

Researchers used data from 22 years of sampling at the La Selva Biological Research Station in Costa Rica to generate statistical models that measure changes in insect species diversity and richness and make future predictions. (Richness is a measurement of how many species are in a given area; diversity takes into account how many species there are as well as the number of individuals of each species.) Researchers looked at two types of insects: caterpillars and parasitoids. Parasitoids are a type of insect whose larvae live as parasites (usually in other insects) that eventually kill their hosts. These types of insects offer an important ecosystem service through species interactions by preventing outbreaks of herbivorous insects (like caterpillars) that can damage wild plant populations or crops in areas of agriculture. 

Forest trees Costa Rica

Photo by Tommy Krombacher on Unsplash

The researchers found that species richness and diversity has declined in both caterpillars and parasitoids. Results suggest that these declines are partly driven by climate change and weather anomalies such as extreme precipitation and episodes of warmer than average temperatures, which have been occurring at an increasing rate at La Selva. Alongside the decreases in diversity and species richness, there has been a decrease in the interaction richness between caterpillars and parasitoids. A reduction in parasitism means that there is less biological control over herbivorous caterpillar outbreaks, which decreases ecosystem stability. By extrapolating the data for the next 100 years, this study predicts there will be a 30% drop in parasitism (compared to the 6.6% drop seen over the 22 year study period). These findings support the hypothesis that climate change is contributing to insect species declines. Further research is needed to explore the impacts of declining species interactions.

Caterpillar Costa Rica

Children with musical education gain greater self-control

Playing a musical instrument requires a battery of unique skills, including being able to quickly and accurately assess incoming sounds, fine motor skills, and the coordination of behavior and feedback from one’s errors and mistakes. Receiving musical education at a young age has been shown to increase spatial-temporal skills. Musicians must often inhibit attention from one hand to focus on the movement of the other; this is called inhibitory control. 

Inhibitory control is not a new idea; in fact, this concept is taught in most Psychology 101 lectures, using an example called the marshmallow test. In this famous experiment, an experimenter would place a marshmallow in front of a child and tell her to wait 15 minutes during the experimenter’s absence. The child was promised a second marshmallow if she had the willpower to wait. Those who waited and chose the delayed gratification tended to have better academic performance as adolescents. 

Sheet music

Photo by Marius Masalar on Unsplash

A recent longitudinal study brings new light to this old topic. The results revealed children in their third year of musical training chose delayed gratification significantly more often than children in sports programs or those not participating in extracurricular activities. A previous study from the same research group showed that music students also had differences in brain activation (measured with fMRI) compared to students who were not involved in music or sports. During tasks that required cognitive control, the music students had increased activation of the inferior frontal gyrus (attentional demand and inhibition), anterior cingulate cortex (emotional control), and insula (self-awareness). 

A boy walking with a ukulele.

People missing the scent region of their brain can still smell

Think about the last time you had a cold. Think how weird it felt to not be able to smell or taste anything just because your nose was clogged up. That is, to an extent, the life of people with anosmia: the term for not being able to smell. Some patients are born with it. For others, it is the result of a neurological diseases, and for others still, it comes from a surgery that removed or damaged the olfactory bulb (OB). For a long time, it was believed that without an OB, a person would not be able to smell, but a team of researchers in Israel found patients who might prove that notion wrong.

Located behind your eyes, the OB is the first area of the brain that receives odor information from receptors your nose. After getting those signals, the OB relays them further into the brain, eventually to the olfactory cortex, where smells are processed and further sent to other areas of the brain. These signals that started in your nose are then able to do complex things, like evoke memories

Patrick J. Lynch via Wikimedia Commons

The actual OB is organized in very specific cell layers that form a spatial odor map organized by the structure of the molecules of whatever you are smelling. This map is divided into zones and clusters of similar odors, so chemicals that, say, signal something spoiled have an area, and different types of natural perfumes have another. It is in fact, estimated that humans can perceive up to a trillion different odors. The OB is also one of the only areas of your brain that continues to produce brain cells, in a process called neurogenesis, throughout your life.

Because of this immense complexity, it is expected that any damage to this area, in particular, would render someone unable to perceive smells normally. Previous studies in humans found that some people born with congenital anosmia have no OB at all and that people with smaller OBs also seem to have a relatively worse sense of smell. Scientists did challenge this notion before, in some rodent studies that showed that there might be a possible recovery. However, the results of these studies were questioned because of technical limitations, or the possibility that rodents were, in fact, using other senses apart from smell.

When Tali Weiss and her colleagues at the Weizmann Institute of Science found a patient that had an otherwise normal sense of smell, but with no apparent OB, they were surprised. In a serendipitous observation, the team was scanning a woman that was supposed to be a “healthy control” for a different study. When analyzing the MRI scan of that patient, the scientists found no OB at all. Curious, they enrolled more participants for this study, and after several scans, they found another woman without an OB who could smell just fine. They performed a battery of different tests that would check every facet of their olfaction. The experiments confirmed the previous results: these two women had a normal sense of smell, but no olfactory bulb. Using fMRI, the researchers measured the brain activity of the two women in response to different smells and found their brain activity to be no different than people with intact OBs.

There was an interesting link, however, between these two people – both were left-handed women. To determine if there was any possibility that the lack of OB is somehow associated with a combination of sex and handedness, the team analyzed the brain scans of 1,113 participants (606 of them women) publicly available through the Human Connectome Project (HCP), a huge project that aims to construct a complete map of the human brain. They found an even more interesting set of results. Out of those participants, there were 3 sets of identical twins in which one twin had no OB and the other twin had a normal OB. In all three cases, the person without an OB could actually smell better than their twin. Overall, in that database, they found that 0.6% of women and 4.25% of left-handed women had the same condition.

NASA via Wikimedia Commons

Two questions remain from this study. First, is there any part of smell for which an intact OB is absolutely necessary? Second, how do these people achieve normal olfaction without OBs? It is possible that there are specific tasks, or maybe even specific smells that the women tested would not be able to perceive, but it seems that for the most part, they can smell normally. As far as how smell is being processed in brains with no OBs, there are different hypotheses being considered. One possibility is that the neurons that usually compose the OB migrated; another possibility is that  other parts of the olfactory circuit, like the upstream mitral cells, took over the OB's responsibilities.  A third possibility is that these women are using a completely different area of the nervous system to capture the chemical signals that we perceive as smell. One way or another, this opens several doors for future research on the neuroscience of olfaction.

This study also opens new avenues of research into how anosmia develops, and what we can do about it. Detecting anosmia early has not been a high priority medical goal. In fact, most people only realize they are not able to smell during their teenage years. These new results show that there might be a mechanism in which the brain is able to adapt to the lack of that structure. If patients with congenital anosmia were diagnosed early, it is possible (although not yet proven) that an odor enrichment program – a month-long training camp for smelling, where participants perform daily tasks to improve their smelling abilities – could help trigger those adaptations.

Child smelling flowers

Concerning the link between handedness, sex, and the OB, the researchers admit being puzzled. Sex differences in human olfaction have been known for a while. In fact, despite usually having OBs of similar size, women tend to have about twice as many neurons in that region than men. However, what that might have to do with this new finding is, for the moment, still a mystery.

Thiago Arzua studies



Medical College of Wisconsin


Woman smelling lavender

The mice most scientists use to study Alzheimer's aren't accurate

Scientists often conduct the first stage of drug trials in mouse models, including mice genetically engineered to develop Alzheimer’s disease. However, the accuracy of mice as a representation of human biology is being challenged daily, including by the authors of this Nature Medicine study in early January 2020.

Led by medical researchers at Washington University in St. Louis, the study shows that the most common Alzheimer’s disease (AD) mouse model, 5XFAD, has an entirely different genetic response to one of AD’s pathological hallmarks – amyloid-beta. In AD, specific neuron proteins are broken into two fragments, called amyloid-beta 40 and 42. These fragments clump together into non-functional masses – the protein version of tumor cells – that form even larger plaques that destroy neuron connections and inhibit brain function. 

A small brown mouse held in the palm of a hand.

This Nature study adds one more sticking point for why mouse studies are not sufficient to investigate Alzheimer’s disease.

 Rama on Wikimedia Commons

However, when analyzing brain cells, like microglia and astrocytes, the mouse cells had entirely different genetic responses to amyloid-b than human cells. Certain genes and proteins were under-expressed in AD-mice microglia and over-expressed in AD-human microglia, compared to normal brains. In addition, astrocyte cell differentiation was only mildly affected by AD in mice, but severely mutated in AD-human brains, leading to the formation of 6 different types of impaired astrocytes. 

The study is one of many contributing to the growing discussion of how accurate Alzheimer’s disease mouse models are and why, if they do not closely match to the human AD disease state, we should continue using them.

A white mouse held in a scientist's hand.

"Insect destroyer" fungus uses tiny, squishy cannons to fire spores

You may have heard of “zombie ants” — insects that are infected with a fungal pathogen that can control their behavior, coercing them into climbing to a high location to better spread fungal spores before meeting their end. But did you know that another species of pathogenic fungus, Entomophthora muscae or “insect destroyer,” could be harnessed by humans to act as a more environmentally friendly insecticide? Although we’ve known for decades that the insect destroyer fungus can infect flies, including the common housefly, we lacked the laboratory tools necessary to actually study the fungus-fly interaction in much detail. 

Fly with insect destroyer fungus

An infected insect.

Researchers at the University of California, Berkeley have identified a particular variety of this fungus that can infect the commonly-used fruit fly model organism, Drosophila melanogaster. This means that all of the tools we’ve accrued over the last century to study D. melanogaster in the lab can now be applied to its interaction with the fungus, making it much easier to learn how pathogens like the insect destroyer infect their host and control their behavior. 

Scientists are also investigating the fungus itself, especially the ways that the fungus spreads its spores, which is a key part of how the fungus is able to infect new victims. Scientists found that E. muscae spores are shot out from cannon-like structures on the dead, infected flies at roughly 10m/s or 22mph — very fast in the world of fungal spores. This even inspired a follow-up study by biophysicists in Denmark that specifically examined the physics of spore ejection. The scientists created tiny, squishy cannons made of silicone that they could load with 3D-printed projectiles and fire with pressurized liquid, mimicking the actual ejection system used by the insect destroyer fungus. It turns out there’s a very specific canon and spore size that maximizes ejection speed and distance, increasing the chances of further fly infection.

Fly on leaf

Coronavirus update: widespread diagnostic testing, bioRxiv, and two public health futures

The outbreak of a new coronavirus is a global public health emergency that has spread to at least 28 countries so far. There's a lot of news and it can be hard to make heads or tails of it all. It's a little overwhelming. Here are a few key updates that we think you should know about. 

A diagnostic test has been authorized for use at public health labs across the U.S.

Until now, samples from suspected cases of the new coronavirus — dubbed "2019-nCoV acute respiratory disease” (where "n" stands for "novel" and "CoV" for "coronavirus") — had to be shipped to Centers for Disease Control and Prevention (CDC) labs. In an announcement on Tuesday, the Food and Drug Administration issued an emergency use authorization to fast-track the diagnostic test and permit its use at any CDC-qualified public health laboratory. The test itself converts specific regions of coronavirus's RNA genome into DNA, makes many copies of it using a process called amplification, and then tests it for the presence of these amplified bits with a glowing dye. Scientists hope that the availability of the test will prevent backlogs and enable the preventative measures that come with a real-time diagnosis.

Preprint repositories are spreading information, and misinformation

Preprint servers like bioRxiv have allowed scientists to share their research faster than ever before by giving papers a place to be read and shared before the peer review process. For perhaps the first time, we are now seeing how these repositories are helping and hurting in a public health response. Data sharing, through for forums like virological.org and the GISAID Initiative, have allowed researchers to sequence and start analyzing the coronavirus at unprecedented speed. At the same time, some scientists worry that publishing (and publicizing) before peer review is placing quantity over quality in this outbreak. 

One preprint has already been withdrawn following widespread criticism, and bioRxiv has put up a banner on top of every page, cautioning viewers that the research posted there has not gone through peer review.

We’ve just put an additional, cautionary note about the use of preprints on every @biorxivpreprint pic.twitter.com/08eSXL4dDi

— John Inglis (@JohnRInglis) February 1, 2020

Two futures for 2019-nCoV

In one of my epidemiology classes this week, we split up into groups and underwent a coronavirus-themed crisis management case study. This is obviously just a simulation, but by day 21, the virus was everywhere and we had to transition from containment to mitigation.

I was struck by a recent article in STAT, which lays out two scenarios of what a future with endemic 2019-nCoV might look like:

One possibility adds this virus to the already four endemic human coronaviruses, which cause common cold and are a lower concern than something like the seasonal flu. Another possibility is a seasonal cycle in which coronavirus transmission dips during summer months due to their intolerance of higher heats and humidity.

We’ll keep checking in with these short roundups, so stay tuned.

Bats' unique immune systems make them stealthy viral reservoirs

In 2001, Nipah virus emerged in India, causing an estimated 66 cases and 45 deaths after people unknowingly drank contaminated raw date palm sap. In 2002, SARS (a coronavirus termed Severe Acute Respiratory Syndrome) arose in Asia, resulting in 8,000 infections and almost 800 deaths globally. And from 2014-2016, the Ebola virus outbreak shocked the world, sickening over 28,000 people and killing over 11,000 across Africa

Coronaviruses (a family of closely related respiratory viruses) have now made headlines again, in the form of 2019-nCoV, the new coronavirus that emerged in Wuhan, China. As of February 2nd, there have been 14,564 cases and 305 deaths from 2019-nCoV, with cases confirmed in 25 countries. All of these alarming outbreaks have one intriguing factor in common: bats. 

bright green virus particle under microscope

Nipah virus is one example of a bat-borne disease that can spill over into humans

NIAID on Flickr

We have known for quite some time that bats were the primary source of both the SARS epidemic and the Nipah virus. The Ebola virus also originates in fruit bats, which can infect other forest animals who then pass the virus to humans. And evidence strongly suggests that bats have played this same role – which scientists term the "reservoir species" – in the coronavirus outbreak. There are over 1,300 known species of bats, making them the second largest group of mammals on Earth. But their strange immune systems that make them the reservoir species for so many viruses are what make them truly special. 

Humans aren't constantly exercising; we jog, or work out for a bit, but then we stop. As a result, unless we are very sick, our body temperature stays around 36.4 degrees Celsius. If we do have a fever, that stimulates an inflammatory response, and our immune system quickly kicks into action, eliminating the foreign pathogen from our bodies. However, bats are constantly exercising: they fly, which increases body temperature and metabolic rate. This led scientists to come up with an initial theory as to why bats have a strange immune system, known as the "Flight as Fever" hypothesis. Because bats' bodies are often put into what, for humans, is a "fever" state, they may be more resistant to viral damage, allowing them to become symptom-less carriers of viral disease. 

In a recent review, virologist Arinjay Banjeree and colleagues summarized the immunological differences between bats and humans to uncover why these animals make such effective viral reservoirs. The first difference they noted was interferon levels. Interferons (IFNs) are an immune substance animals secrete to eliminate viruses. Humans have them, and so do bats. When grown in labs, analysis showed that bat cell lines produce higher levels of type I IFNs than human cell lines. Type I IFN is responsible for a variety of anti-viral jobs including limiting viral replication, killing infected cells, and activating other immune cells. Though wild bats have been shown to carry high IFN levels as well, the link between bat cell line behavior in the lab and bat's natural immune system needs more work.

There's more strangeness, on top of their high interferon levels and flight-induced fevers. A study on Big Brown Bats revealed that bats have lower levels of inflammatory cytokines in their blood than we do. Inflammatory cytokines are substances in our bodies that race to the site of an infection, bringing immune cells with them, which helps to quench it locally before it can spread. This allows infected bats to keep spreading diseases to other animals without becoming victims themselves.

Bats are ecologically important and fascinating animals, but we must be conscious of limiting human-bat interactions to stop the spread of diseases

 Photo by Hans Veth on Unsplash

Environmental stressors – such as drought or extreme temperatures – can increase the rate at which bats pass diseases to humans. Not only does stress in general tend to reduce animals' immune functions, but stressors such as shortages of food or water can force bats to migrate, spreading disease further. In fact, a recent "spillover" (the passing of a virus from a reservoir species into a new host) of Hendra virus from fruit bats in Australia correlated with a food shortage for local bats due to a climate shift. Because the bats were under nutritional stress, they were more infectious, which coincided with their moving into new territories in search of food. This created a perfect storm of new hosts and infectious reservoirs, resulting in an outbreak of Hendra among horses.  

Attempts to study bat immune cells in the lab haven't made much progress. Many bats do not develop the symptoms of the viral diseases they carry, and when they do, attempts to culture their cells in the lab have been unsuccessful (essentially, the cells cannot survive in a laboratory environment, and they die). In 2018, a Gammaherpesvirus was isolated from Big Brown Bats and maintained in tissue culture, representing a huge leap forward in bat-virology research. However, progress has been slow and restricted to just a few cells types from a few species of bats. 

With the great diversity in bat species, their unique immune adaptations that support asymptomatic carriage of viral diseases, and the fact that bats are in close contact with humans around the world, it is no great surprise that bat-borne diseases have followed humans throughout history. From Ebola to herpes, bats represent a reservoir for a number of devastating diseases and viral outbreaks due to these animals is likely to continue increasing. With so much left to learn and discover about these little creatures, it's no wonder they remain at the forefront of human health headlines. 

Marnie Willman studies



University of Manitoba Bannatyne and National Microbiology Laboratory


fruit bat in tree

a large bat hanging in a pine tree

Yeah, one fish, two fish, but can fish actually count?

Understanding and using quantitative information is important for animals to compete for resources, protect themselves from predators, get access to territories and for reproductive benefits. Certain species also exhibit an awareness of numerosity, or being able to differentiate between groups of varying numbers, at fine scales. While humans rely on a symbolic sense of numerosity (we have symbols and names for counts), animals depend on non-symbolic representations of numbers. Although they use this information for their survival, does this mean they are really counting? 

Researchers from the lab of Giorgio Vallortigara have shown that zebrafish do in fact use ordinal counting in order to get to a “reward." Ordinal counting keeps track of a position (as in, the second door out of seven), as opposed to cardinal counting, which tracks an amount ("there are seven doors"). Zebrafish were trained to exit an arena with seven identical exits in a corridor, using only the second exit. This was done by blocking the other exits with a clear sheet of plastic. On the other side of the corridor was a reward of food and other fish. If the fish swam towards other exits, they did not receive any reward. But what happens when all doors are up for ‘swims’? 

Post training, the fish were tested by decreasing the length of the corridor, decreasing the distance between exits, or increasing the number of exits. In the first two experiments, they chose the second exit with a frequency greater than random chance, indicating that they were in fact “counting” to choose which exit to use.

In the last experiment, along with choosing the second exit significantly more than the others, they also chose the second-to-last exit (second from the other end of the corridor) more than chance level. The higher numbers seemed to "confuse" the fish. In such contexts, the fish switched to using spatial feedback, along with ordinal information, to increase their chances of getting lunch with their pals.

Developing zebrafish brain

Confocal micrograph of the developing zebrafish brain

Dr. Steve Wilson. CC BY

Although evidence of numerical skills has been reported in birds, amphibians, mammals and even insects, studying it in a well-established model system like zebrafish opens up avenues to decode the mechanisms underlying this behaviour.