Scientists find record warm water in Antarctica, pointing to cause behind troubling glacier melt

Antarctica illustration

A team of scientists has observed, for the first time, the presence of warm water at a vital point underneath a glacier in Antarctica -- an alarming discovery that points to the cause behind the gradual melting of this ice shelf while also raising concerns about sea-level rise around the globe.

"Warm waters in this part of the world, as remote as they may seem, should serve as a warning to all of us about the potential dire changes to the planet brought about by climate change," explains David Holland, director of New York University's Environmental Fluid Dynamics Laboratory and NYU Abu Dhabi's Center for Global Sea Level Change, which conducted the research. "If these waters are causing glacier melt in Antarctica, resulting changes in sea level would be felt in more inhabited parts of the world."

The recorded warm waters -- more than two degrees above freezing -- flow beneath the Thwaites Glacier, which is part of the Western Antarctic Ice Sheet. The discovery was made at the glacier's grounding zone -- the place at which the ice transitions between resting fully on bedrock and floating on the ocean as an ice shelf and which is key to the overall rate of retreat of a glacier.

Thwaites' demise alone could have significant impact globally.

It would drain a mass of water that is roughly the size of Great Britain or the state of Florida and currently accounts for approximately 4 percent of global sea-level rise. Some scientists see Thwaites as the most vulnerable and most significant glacier in the world in terms of future global sea-level rise -- its collapse would raise global sea levels by nearly one meter, perhaps overwhelming existing populated areas.

While the glacier's recession has been observed over the past decade, the causes behind this change had previously not been determined.

"The fact that such warm water was just now recorded by our team along a section of Thwaites grounding zone where we have known the glacier is melting suggests that it may be undergoing an unstoppable retreat that has huge implications for global sea level rise," notes Holland, a professor at NYU's Courant Institute of Mathematical Sciences.

The scientists' measurements were made in early January, after the research team created a 600-meter deep and 35-centimeter wide access hole and deployed an ocean-sensing device to measure the waters moving below the glacier's surface. This device gauges the turbulence of the water as well as other properties such as temperature. The result of turbulence is the mixing of fresh meltwater from the glacier and salty water from the ocean.

It marks the first time that ocean activity beneath the Thwaites Glacier has been accessed through a bore hole and that a scientific instrument measuring underlying ocean turbulence and mixing has been deployed. The hole was opened on January 8 and 9 and the waters beneath the glacier measured January 10 and 11.

Aurora Basinski, an NYU graduate student who made the turbulence measurement, said, "From our observations into the ocean cavity at the grounding zone we observed not only the presence of warm water, but also its turbulence level and thus its efficiency to melt the ice shelf base."

Another researcher, Keith Nicholls, a scientist with the British Antarctic Survey, added, "This is an important result as this is the first time turbulent dissipation measurements have been made in the critical grounding zone of the West Antarctic Ice Sheet."

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Space super-storm likelihood estimated from longest period of magnetic field observations

A 'great' space weather super-storm large enough to cause significant disruption to our electronic and networked systems occurred on average once in every 25 years according to a new joint study by the University of Warwick and the British Antarctic Survey.

By analysing magnetic field records at opposite ends of the Earth (UK and Australia), scientists have been able to detect super-storms going back over the last 150 years.

This result was made possible by a new way of analysing historical data, pioneered by the University of Warwick, from the last 14 solar cycles, way before the space age began in 1957, instead of the last five solar cycles currently used.

The analysis shows that 'severe' magnetic storms occurred in 42 out of the last 150 years, and 'great' super-storms occurred in 6 years out of 150. Typically, a storm may only last a few days but can be hugely disruptive to modern technology. Super-storms can cause power blackouts, take out satellites, disrupt aviation and cause temporary loss of GPS signals and radio communications.

Lead author Professor Sandra Chapman, from the University of Warwick's Centre for Fusion, Space and Astrophysics, said: "These super-storms are rare events but estimating their chance of occurrence is an important part of planning the level of mitigation needed to protect critical national infrastructure.

"This research proposes a new method to approach historical data, to provide a better picture of the chance of occurrence of super-storms and what super-storm activity we are likely to see in the future."

The Carrington storm of 1859 is widely recognised as the largest super-storm on record, but predates even the data used in this study. The analysis led by Professor Chapman estimates what amplitude it would need to have been to be in the same class as the other super-storms- and hence with a chance of occurrence that can be estimated.

Professor Richard Horne, who leads Space Weather at the British Antarctic Survey, said: "Our research shows that a super-storm can happen more often than we thought. Don't be misled by the stats, it can happen any time, we simply don't know when and right now we can't predict when."

Space weather is driven by activity from the sun. Smaller scale storms are common, but occasionally larger storms occur that can have a significant impact.

One way to monitor this space weather is by observing changes in the magnetic field at the earth's surface. High quality observations at multiple stations have been available since the beginning of the space age (1957). The sun has an approximately 11-year cycle of activity which varies in intensity and this data, which has been extensively studied, covers only five cycles of solar activity.

If we want a better estimate of the chance of occurrence of the largest space storms over many solar cycles, we need to go back further in time. The aa geomagnetic index is derived from two stations at opposite ends of the earth (in UK and Australia) to cancel out the earth's own background field. This goes back over 14 solar cycles or 150 years, but has poor resolution.

Using annual averages of the top few percent of the aa index the researchers found that a 'severe' super-storm occurred in 42 years out of 150 (28%), while a 'great' super-storm occurred in 6 years out of 150 (4%) or once in every 25 years. As an example, the 1989 storm that caused a major power blackout of Quebec was a great storm.

In 2012 the Earth narrowly avoided trouble when a coronal mass ejection from the Sun missed the Earth and went off in another direction. According to satellite measurements if it had hit the Earth it would have caused a super-storm.

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New injection technique may boost spinal cord injury repair efforts

Spinal cord injury concept

Writing in the journal Stem Cells Translational Medicine, an international research team, led by physician-scientists at University of California San Diego School of Medicine, describe a new method for delivering neural precursor cells (NSCs) to spinal cord injuries in rats, reducing the risk of further injury and boosting the propagation of potentially reparative cells.

The findings are published in the Jan. 29, 2020 print issue.

NSCs hold great potential for treating a variety of neurodegenerative diseases and injuries to the spinal cord. The stem cells possess the ability to differentiate into multiple types of neural cell, depending upon their environment. As a result, there is great interest and much effort to use these cells to repair spinal cord injuries and effectively restore related functions.

But current spinal cell delivery techniques, said Martin Marsala, MD, professor in the Department of Anesthesiology at UC San Diego School of Medicine, involve direct needle injection into the spinal parenchyma -- the primary cord of nerve fibers running through the vertebral column. "As such, there is an inherent risk of (further) spinal tissue injury or intraparechymal bleeding," said Marsala.

The new technique is less invasive, depositing injected cells into the spinal subpial space -- a space between the pial membrane and the superficial layers of the spinal cord.

"This injection technique allows the delivery of high cell numbers from a single injection," said Marsala. "Cells with proliferative properties, such as glial progenitors, then migrate into the spinal parenchyma and populate over time in multiple spinal segments as well as the brain stem. Injected cells acquire the functional properties consistent with surrounding host cells."

Marsala, senior author Joseph Ciacci, MD, a neurosurgeon at UC San Diego Health, and colleagues suggest that subpially-injected cells are likely to accelerate and improve treatment potency in cell-replacement therapies for several spinal neurodegenerative disorders in which a broad repopulation by glial cells, such as oligodendrocytes or astrocytes, is desired.

"This may include spinal traumatic injury, amyotrophic lateral sclerosis and multiple sclerosis," said Ciacci.

The researchers plan to test the cell delivery system in larger preclinical animal models of spinal traumatic injury that more closely mimic human anatomy and size. "The goal is to define the optimal cell dosing and timing of cell delivery after spinal injury, which is associated with the best treatment effect," said Marsala.

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Modeling study estimates spread of 2019 novel coronavirus

Coronavirus diagnosis concept

New modelling research, published in The Lancet, estimates that up to 75,800 individuals in the Chinese city of Wuhan may have been infected with 2019 novel coronavirus (2019-nCoV) as of January 25, 2020.

Senior author Professor Gabriel Leung from the University of Hong Kong highlights: "Not everyone who is infected with 2019-nCoV would require or seek medical attention. During the urgent demands of a rapidly expanding epidemic of a completely new virus, especially when system capacity is getting overwhelmed, some of those infected may be undercounted in the official register."

He explains: "The apparent discrepancy between our modelled estimates of 2019-nCoV infections and the actual number of confirmed cases in Wuhan could also be due to several other factors. These include that there is a time lag between infection and symptom onset, delays in infected persons coming to medical attention, and time taken to confirm cases by laboratory testing, which could all affect overall recording and reporting."

The new estimates also suggest that multiple major Chinese cities might have already imported dozens of cases of 2019-nCoV infection from Wuhan, in numbers sufficient to initiate local epidemics.

The early estimates underscore that it will likely take rapid and immediate scale-up of substantial public health control measures to prevent large epidemics in areas outside Wuhan. Further analyses suggest that if transmissibility of 2019-nCoV could be reduced, both the growth rate and size of local epidemics in all cities across China could be reduced.

"If the transmissibility of 2019-nCoV is similar nationally and over time, it is possible that epidemics could be already growing in multiple major Chinese cities, with a time lag of one to two weeks behind the Wuhan outbreak," says lead author Professor Joseph Wu from the University of Hong Kong. "Large cities overseas with close transport links to China could potentially also become outbreak epicentres because of substantial spread of pre-symptomatic cases unless substantial public health interventions at both the population and personal levels are implemented immediately."

According to Professor Gabriel Leung: "Based on our estimates, we would strongly urge authorities worldwide that preparedness plans and mitigation interventions should be readied for quick deployment, including securing supplies of test reagents, drugs, personal protective equipment, hospital supplies, and above all human resources, especially in cities with close ties with Wuhan and other major Chinese cities."

In the study, researchers used mathematical modelling to estimate the size of the epidemic based on officially reported 2019-nCoV case data and domestic and international travel (i.e., train, air, road) data. They assumed that the serial interval estimate (the time it takes for infected individuals to infect other people) for 2019-nCoV was the same as for severe acute respiratory syndrome (SARS: table 1). The researchers also modelled potential future spread of 2019-nCoV in China and internationally, accounting for the potential impact of various public health interventions that were implemented in January 2020 including use of face masks and increased personal hygiene, and the quarantine measures introduced in Wuhan on January 23.

The researchers estimate that in the early stages of the Wuhan outbreak (from December 1, 2019 to January 25, 2020) each person infected with 2019-nCoV could have infected up to 2-3 other individuals on average, and that the epidemic doubled in size every 6.4 days. During this period, up to 75,815 individuals could have been infected in Wuhan.

Additionally, estimates suggest that cases of 2019-nCoV infection may have spread from Wuhan to multiple other major Chinese cities as of January 25, including Guangzhou (111 cases), Beijing (113), Shanghai (98), and Shenzhen (80; figure 3). Together these cities account for over half of all outbound international air travel from China.

While the estimates suggest that the quarantine in Wuhan may not have the intended effect of completely halting the epidemic, further analyses suggest that if transmissibility of 2019-nCoV could be reduced by 25% in all cities nationally with expanded control efforts, both the growth rate and size of local epidemics could be substantially reduced. Moreover, a 50% reduction in transmissibility could shift the current 2019-nCoV epidemic from one that is expanding rapidly, to one that is slowly growing (figure 4).

"It might be possible to reduce local transmissibility and contain local epidemics if substantial, even draconian, measures that limit population mobility in all affected areas are immediately considered. Precisely what and how much should be done is highly contextually specific and there is no one-size-fits-all set of prescriptive interventions that would be appropriate across all settings," says co-author Dr Kathy Leung from the University of Hong Kong. "On top of that, strategies to drastically reduce within-population contact by cancelling mass gatherings, school closures, and introducing work-from-home arrangements could contain the spread of infection so that the first imported cases, or even early local transmission, does not result in large epidemics outside Wuhan."

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Scientists boost gene-editing tools to new heights in human stem cells

During the past decade, the gene editing tool CRISPR has transformed biology and opened up hopeful avenues to correct deadly inherited diseases. Last fall, scientists began the first human clinical trials using CRISPR to combat diseases like cancer. They remove some of a person's cells, CRISPR edit the DNA, and then inject the cells back in, where hopefully, they will cure the disease.

But along with this promise of regenerative, personalized medicine, CRISPR can also have significant safety limitations. CRISPR may not edit in the right place (so-called off-target gene effects) or not being terribly efficient (successful editing may only be achieved in about 10% of the time for every available cell target).

These limitations have frustrated scientists such as Arizona State University's David Brafman, a cell bioengineer. Brafman initial hopes are to use gene editing to get at the heart of uncovering the causes of studies in his lab of neurodegenerative diseases like Alzheimer's.

"We study neurodegenerative diseases like Alzheimer's and use stem cells to study specific mutations or risk factors associated with Alzheimer's disease," said Brafman, a biomedical engineering faculty member in ASU's Ira A. Fulton Schools of Engineering. "We are not necessarily a gene-editing tool development lab, but we were running into difficulty generating stem cell lines by using a traditional CRISPR-based editing approach. For reasons that are still unknown, stem cells are really resistant to that sort of genetic modification."

Green light means go

Now, Brafman, using a new update to the CRISPR base editing technology originally developed in the lab of David Liu at Harvard, has vastly outperformed previous efforts by making highly accurate, single DNA base editing with an efficiency of up to 90% of human stem cells. The results were published in the journal Stem Cell Reports.

"Previously, with CRISPR, it's just been a random guess," said Brafman. "And so, if you are picking at random stem cells and the efficiency is low, you'll likely get only 10% or 5% because you have no idea if the edits have been made -- the cell isn't telling you."

Brafman's lab has developed a new TREE method (an acronym short for transient reporter for editing enrichment, or TREE), which allows for bulk enrichment of DNA base-edited cell populations -- -and for the first time, high efficiency in human stem cell lines.

""Most of the studies are done in immortalized cell lines or cancer cell lines, which are relatively easy to edit," said Brafman. "This is the first example of using base editors in pluripotent stem cells, which is a very valuable cell population to genetically modify. We envision this method will have important implications for the use of human stem cell lines in developmental biology, disease modeling, drug screening and tissue engineering applications,"

Last year, they had shown that their TREE approach can work in human cell lines, but wanted to further push the technology further to find a way to rapidly and efficiently edit human stem cell lines.

Unlike CRISPR, which cuts across both DNA stands, their TREE method only makes a single strand nick in DNA. For example, when a single DNA base is successfully edited from a C to a T, a protein gives off a signal, turning from blue to green.

"Now, if a cell is telling you, 'if I'm glowing green I have a 90% chance of being edited you are going to have better luck identifying edited populations," said Brafman. "Then, you can exclude all of the cells that are not edited. We isolate single cells that are glowing green, then grow those up into clonal populations that you are able to expand indefinitely."

Targeting Alzheimer's

Pluripotent stem cells are valued for regenerative medicine because they have the ability to become or differentiate into any cell type in the human body.

Brafman explains that there are two general sources, "embryonic stem cells, which are derived from the inner cell mass of a preimplantation blastocyst, and then there are induced pluripotent stem cells, which are derived from taking somatic cells like skin or blood from patients."

Brafman's lab uses the induced pluripotent stem cells for their research.

"For this study, we used pluripotent stem cells from both healthy patients and then patients with Alzheimer's disease. Some of the genes that we were interested in modulating are related to Alzheimer's disease. The majority of the patients suffering from Alzheimer's disease suffer from late onset, or sporadic Alzheimer's disease."

To provide their proof-of-concept, they targeted the APOE gene, which can come in three flavors. One of the three gene variants, called APOE4, has been associated with a higher risk for late onset Alzheimer's disease. For the study, they introduced single DNA based edits into the APOE gene.

"That's why we are interested in having these cells," said Brafman. "They are representative of the neurons and the various cell types in the central nervous system with patients with these various risk factors. Then, we can understand why an APOE variant can increase or decrease risk, and then we can start targeting those pathways that are affected."

Not only could TREE make single DNA edits to the APOE4 gene, but unlike CRISPR, make highly accurate corrections to both copies of the APOE4 gene that humans possess.

"The traditional CRISPR approach is that you have to edit once to get a heterozygous edit , then isolate that clone, edit again to get another heterozygous edit," said Brafman. "So, it's very inefficient in that way. We are generating homozygous edits at an efficiency approaching 90%. I haven't seen any other technologies that can do that in pluripotent stem cells."

In addition, TREE could also be used to engineer critical gene knockout mutations into stem cell lines. "The most fundamental experiment you can do if a gene has important implications in disease, development or physiology is knock it out," said Brafman. That opens up a whole bunch of questions that we can address. Using APOE as a case study, now we can knock out APOE in these cells if you don't have APOE at all. Is it beneficial? Detrimental? Or no difference?"

Complex cases

While diseases like sickle-cell anemia or cystric fibrosis are caused by single mutations in DNA, for most diseases and leading causes of death, like heart disease or high blood pressure, are complex, and involve multiple genes. Brafman wanted to also address the complex, root causes of Alzheimer's.

"Especially as it related to Alzheimer's disease, there can be multiple risk factors that act in concert, so we wanted a way to introduce multiple edits simultaneously in pluripotent stem cells. Because otherwise, you would have to take this sequential iterative approach, where you introduce one edit, isolate a clonal population introduce another edit, and so on.

They successfully demonstrated that TREE could be used to make new stem cell lines that had been simultaneously edited at multiple gene locations. Their results showed that more than 80% of stem clones had been targeted at all three different gene sites, and with all clones editing both gene copies.

"We found that if you multiplex you still get the same efficiency of editing as you would if you just edited a single allele," said Brafman. "Now, we can use these cells as in vitro models to study the disease and screen drugs."

Brafman is hopeful that their new tools will generate excitement in the gene editing community, and spur others on to make new discoveries.

Read more at Science Daily

Red alert as Arctic lands grow greener

New research techniques are being adopted by scientists tackling the most visible impact of climate change -- the so-called greening of Arctic regions.

The latest drone and satellite technology is helping an international team of researchers to better understand how the vast, treeless regions called the tundra is becoming greener.

As Arctic summer temperatures warm, plants are responding. Snow is melting earlier and plants are coming into leaf sooner in spring. Tundra vegetation is spreading into new areas and where plants were already growing, they are now growing taller.

Understanding how data captured from the air compare with observations made on the ground will help to build the clearest picture yet of how the northern regions of Europe, Asia and North America are changing as the temperature rises.

Now a team of 40 scientists from 36 institutions, led by two National Geographic Explorers, have revealed that the causes of this greening process are more complex -- and variable -- than was previously thought.

Researchers from Europe and North America are finding that the Arctic greening observed from space is caused by more than just the responses of tundra plants to warming on the ground. Satellites are also capturing other changes including differences in the timing of snowmelt and the wetness of landscapes.

Lead author Dr Isla Myers-Smith, of the University of Edinburgh's School of GeoSciences, said: "New technologies including sensors on drones, planes and satellites, are enabling scientists to track emerging patterns of greening found within satellite pixels that cover the size of football fields."

Professor Scott Goetz of the School of Informatics, Computing and Cyber Systems at Northern Arizona University, says this research is vital for our understanding of global climate change. Tundra plants act as a barrier between the warming atmosphere and huge stocks of carbon stored in frozen ground.

Changes in vegetation alter the balance between the amount of carbon captured and its release into the atmosphere. Small variations could significantly impact efforts to keep warming below 1.5 degrees centigrade -- a key target of the Paris Agreement. The study will help scientists to figure out which factors will speed up or slow down warming.

Co-lead author Dr Jeffrey Kerby, who was a Neukom Fellow at Dartmouth College while conducting the research, said: "Besides collecting new imagery, advances in how we process and analyse these data -- even imagery that is decades old -- are revolutionising how we understand the past, present, and future of the Arctic."

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'Spring forward' to daylight saving time brings surge in fatal car crashes

Fatal car accidents in the United States spike by 6% during the workweek following the "spring forward" to daylight saving time, resulting in about 28 additional deaths each year, according to new University of Colorado Boulder research.

The study, published January 30 in the journal Current Biology, also found that the farther west a person lives in his or her time zone, the higher their risk of a deadly crash that week.

"Our study provides additional, rigorous evidence that the switch to daylight saving time in spring leads to negative health and safety impacts," said senior author Celine Vetter, assistant professor of integrative physiology. "These effects on fatal traffic accidents are real, and these deaths can be prevented."

The findings come at a time when numerous states, including Oregon, Washington, California and Florida, are considering doing away with the switch entirely, and mounting research is showing spikes in heart attacks, strokes, workplace injuries and other problems in the days following the time change.

For the study -- the largest and most detailed to date to assess the relationship between the time change and fatal motor vehicle accidents -- the researchers analyzed 732,835 accidents recorded through the U.S. Fatality Analysis Reporting System from 1996 to 2017. They excluded Arizona and Indiana, where Daylight Savings Time was not consistently observed.

After controlling for factors like year, season and day of the week, they found a consistent rise in fatal accidents in the week following the spring time change. Notably, that spike moved in 2007, when the Energy Policy Act extended daylight saving time to begin on the second Sunday of March instead of the first Sunday in April.

"Prior to 2007, we saw the risk increase in April, and when daylight saving time moved to March, so did the risk increase," said Vetter. "That gave us even more confidence that the risk increase we observe is indeed attributable to the daylight saving time switch, and not something else."

With the arrival March 9 of daylight saving time, clocks shift forward by one hour, and many people will miss out on sleep and drive to work in darkness -- both factors that can contribute to crashes.

Those on the western edge of their time zone, in places like Amarillo, Texas, and St. George, Utah, already get less sleep on average than their counterparts in the east -- about 19 minutes less per day, research shows -- because the sun rises and sets later but they still have to be at work when everyone else does.

"They already tend to be more misaligned and sleep-deprived, and when you transition to daylight saving time it makes things worse," said first author Josef Fritz, a postdoctoral researcher in the Department of Integrative Physiology. In such western regions, the spike in fatal accidents was more than 8%, the study found.

The increase kicks in right away, on the Sunday when the clocks spring forward, and the bulk of the additional fatal accidents that week occur in the morning.

Changes in accident patterns also occur after the "fall back" time change, the study showed, with a decline in morning accidents and a spike in the evening, when darkness comes sooner.

Because they balance each other out, there is no overall change in accidents during the "fall back" week.

In all, over the course of the 22 years of data analyzed, about 627 people died in fatal car accidents associated with the spring shift to Daylight Savings Time, the study estimated.

Because the data only include the most severe of car accidents, the authors believe the results underestimate the true risk increase to drivers when time springs forward.

"Our results support the theory that abolishing time changes completely would improve public health," said Vetter. "But where do we head from here? Do we go to permanent standard time or permanent daylight saving time?"

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Cycling to work? You may live longer

People who cycle to work have a lower risk of dying, a New Zealand study has found.

The study, by researchers from the University of Otago, Wellington, the University of Melbourne and the University of Auckland, has just been published in the International Journal of Epidemiology.

Lead researcher Dr Caroline Shaw, from the Department of Public Health at the University of Otago, Wellington, says people who cycled to work had a 13 per cent reduction in mortality during the study, likely as a result of the health benefits of physical activity. There was no reduction in mortality for those who walked or took public transport to work.

The researchers used data from the New Zealand Census-Mortality Study, which links census and mortality records, to do follow-up studies of the population for three to five years following the 1996, 2001 and 2006 censuses, when respondents were asked: 'On X date (census day), what was the one main way you travelled to work -- that is, the one you used for the greatest distance?'

Dr Shaw says the study, which analysed data from 3.5 million New Zealanders, is one of the largest ever cohort studies to examine the association between mode of travel to work and mortality outcomes.

"We studied 80 per cent of the working-age population of New Zealand over a 15-year period, so it is highly representative."

Dr Shaw says increasing 'active transport' is being promoted as a way of addressing health and environmental issues, but the association between different modes of transport, such as cycling, walking and public transport, and health outcomes has remained unclear.

The study found more than 80 per cent of people in New Zealand travelled to work by car on census day, with only five per cent walking and three per cent cycling.

"There were gender differences in mode of travel to work, with two per cent of women cycling compared with four per cent of men, but more women walking or jogging (seven per cent), compared with men (five per cent). A higher proportion of younger people cycled, walked or took public transport compared with older people."

Dr Shaw says the census data provided no details about the physical intensity of the commute, so those who lived in the inner city and walked 200 metres to work were in the same category as those who walked briskly up and down a hill for 30 minutes to get to and from work.

"We saw no increase in road traffic injury deaths associated with walking and cycling, although the New Zealand transport system at the time of these studies was heavily car-dominated and roads seldom made allowances for pedestrians and cyclists."

Dr Shaw says the findings lend support for initiatives to increase the number of people commuting to work by bike.

"Increasing cycling for commuting to work in a country with low levels of cycling like New Zealand will require policies directed at both transport and urban planning, such as increasing housing density and implementing cycling networks."

While the study found no association between walking or taking public transport to work and a reduction in mortality, Dr Shaw says there are other reasons to promote these modes of transport.

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Anti-solar cells: A photovoltaic cell that works at night

Solar panels against night sky background.

What if solar cells worked at night? That's no joke, according to Jeremy Munday, professor in the Department of Electrical and Computer Engineering at UC Davis. In fact, a specially designed photovoltaic cell could generate up to 50 watts of power per square meter under ideal conditions at night, about a quarter of what a conventional solar panel can generate in daytime, according to a concept paper by Munday and graduate student Tristan Deppe. The article was published in, and featured on the cover of, the January 2020 issue of ACS Photonics.

Munday, who recently joined UC Davis from the University of Maryland, is developing prototypes of these nighttime solar cells that can generate small amounts of power. The researchers hope to improve the power output and efficiency of the devices.

Munday said that the process is similar to the way a normal solar cell works, but in reverse. An object that is hot compared to its surroundings will radiate heat as infrared light. A conventional solar cell is cool compared to the sun, so it absorbs light.

Space is really, really cold, so if you have a warm object and point it at the sky, it will radiate heat toward it. People have been using this phenomenon for nighttime cooling for hundreds of years. In the last five years, Munday said, there has been a lot of interest in devices that can do this during the daytime (by filtering out sunlight or pointing away from the sun).

Generating power by radiating heat

There's another kind of device called a thermoradiative cell that generates power by radiating heat to its surroundings. Researchers have explored using them to capture waste heat from engines.

"We were thinking, what if we took one of these devices and put it in a warm area and pointed it at the sky," Munday said.

This thermoradiative cell pointed at the night sky would emit infrared light because it is warmer than outer space.

"A regular solar cell generates power by absorbing sunlight, which causes a voltage to appear across the device and for current to flow. In these new devices, light is instead emitted and the current and voltage go in the opposite direction, but you still generate power," Munday said. "You have to use different materials, but the physics is the same."

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People may lie to appear honest

People may lie to appear honest if events that turned out in their favor seem too good to be true, according to new research published by the American Psychological Association.

"Many people care greatly about their reputation and how they will be judged by others, and a concern about appearing honest may outweigh our desire to actually be honest, even in situations where it will cost us money to lie," said lead researcher Shoham Choshen-Hillel, PhD, a senior lecturer at the School of Business Administration and Center for the Study of Rationality at The Hebrew University of Jerusalem. "Our findings suggest that when people obtain extremely favorable outcomes, they anticipate other people's suspicious reactions and prefer lying and appearing honest over telling the truth and appearing as selfish liars."

The study found similar findings about lying to appear honest in a series of experiments conducted with lawyers and college students in Israel, as well as online participants in the United States and United Kingdom. The research was published online in the Journal of Experimental Psychology: General.

In one experiment with 115 lawyers in Israel, the participants were told to imagine a scenario where they told a client that a case would cost between 60 and 90 billable hours. The lawyer would be working in an office where the client wouldn't know how many hours were truly spent on the case. Half of the participants were told they had worked 60 hours on the case while the other half were told they worked 90 hours. Then they were asked how many hours they would bill the client. In the 60-hour group, the lawyers reported an average of 62.5 hours, with 17% of the group lying to inflate their hours. In the 90-hour group, the lawyers reported an average of 88 hours, with 18% of the group lying to report fewer hours than they had actually worked.

When asked for an explanation for the hours they billed, some lawyers in the 90-hour group said they worried that the client would think he had been cheated because the lawyer had lied about the number of billable hours.

In another experiment, 149 undergraduate students at an Israeli university played online dice-rolling and coin-flipping games in private and then reported their scores to a researcher. The participants received approximately 15 cents for each successful coin flip or dice roll they reported. The computer program was manipulated for half of the students so they received perfect scores in the games, while the other group had random outcomes based on chance. In the perfect-score group, 24% underreported their number of wins even though it cost them money, compared with 4% in the random-outcome group.

"Some participants overcame their aversion toward lying and the monetary costs involved just to appear honest to a single person who was conducting the experiment," Choshen-Hillel said.

In another online experiment with 201 adults from the United States, participants were told to imagine a scenario where they drove on many work trips for a company that had a maximum monthly compensation of 400 miles. They were told that most employees reported 280 to 320 miles per month.

Half of the participants were told they had driven 300 miles in a month while the other half were told they drove 400 miles. When the participants were asked how many miles they would report, the 300-mile group told the truth and reported an average of 301 miles. For the 400-mile group, the participants reported an average of 384 miles, with 12% lying and underreporting their mileage. There were similar findings in another online experiment with 544 participants in the United Kingdom.

Choshen-Hillel said she believes the study findings would apply in the real world, but there could be situations where the amount of money or other high stakes would lead people to tell the truth even if they might appear dishonest.

Read more at Science Daily