Lab Notes

As we age, our brain becomes more vulnerable to different diseases. Parkinson's disease is one such debilitating disorder. It affects more than 10 million people worldwide. Men are 1.5 times more likely than women to develop it. Most people with Parkinson's disease develop it when they are around 60 years old, when the motor cells in their brains begin to die off, leading to a loss of motor control.

This brain cell death is caused by clumping of alpha-synuclein (α-syn) proteins. We know that α-syn is found in the region of the neuron that sends packages of neurochemical signals, which are called vesicles. But we don't know what this protein does in a healthy brain. This might hold a clue to why α-syn begins clumping. 

A new study in Nature Communications provides more context into their function. Scientists used artificial cell membranes to mimic the vesicles sent out by cells. By adding α-syn to these vesicles, they found that it sticks like glue to the inside of the vesicle and keeps these tiny packages of neurochemicals at their origins until the cell is ready to send them out. This might explain how one abnormally clumping α-syn protein can spread and build up inside of neurons in people with Parkinson's disease. This very basic scientific finding could lead to better treatments for the disease in the future.

Gray wolves were locally extinct in Germany since the 1800s, but recently have successfully recolonized the northeastern region of the country by crossing the border from Poland. More than 100 wolf packs were counted in 2019. This is an impressive feat, but one obstacle stands in the way of a robust wolf population in the country — vehicle collisions.   

Road accidents account for more than 75 percent of all known wolf mortality in Germany. Fortunately, realizing the enormous benefit to both humans and wildlife that comes from reducing animals in roadways, efforts have been made around the world to build “green bridges.” These bridges provide wildlife with safe crossing opportunities over roads and highways, helping them move freely throughout the landscape.

The novelty of these bridges means that researchers are still testing out if, and how, different wildlife species will utilize them. Will prey species be deterred if they sense that predators use the same crossings? Will animals use the crossings during the day, when noise from the road is peaking, or merely at night when human disturbance is lower? These and other questions led researchers to examine one such green bridge built over a highway connecting Berlin to Poland. 

Using camera traps, which monitor the activities of animals with motion-activated photos and videos, researchers determined that wolves actively use the green bridge to safely cross the highway, and that their presence doesn’t seem to deter deer and boar (their main prey) from using the same crossing. First constructed in 2012, when wolves were still absent from the region, the bridge has quickly become a known safe crossing destination for wolves. The first wolf crossing was recorded in late 2015, and the wolves used the bridge over 85 times the following year. The bridge is one of seven such green bridges throughout the German state of Brandenburg. 

The results from this study help wildlife biologists determine the myriad benefits of green bridges. Wolves use the bridges more frequently during the winter months, which could be due to the seasonal need to expand their hunting range. In contrast, deer and wild boar tend to cross more in the spring and summer. All species crossed the bridge more during dawn and dusk, and least often during the day, when human activity is highest.

These analyses of species use of green bridges and other wildlife crossings are important for understanding how we can best design and implement them. Studies like this can help determine where to place green bridges in the landscape to optimize their use by wildlife species and maximize the benefit to humans by keeping animals out of the roads, facilitating our coexistence as we endeavor to lighten our footprint on the landscape.

To make good decisions, both humans and animals need to collect evidence and integrate new information and knowledge. Lots of research in psychology and the cognitive sciences has been done on understanding human decision-making. However, scientists still don't fully understand how decisions are made on a neuronal level: How do neurons in our brains and nervous systems guide our behavior?

To find answers to those questions, a pair of scientists from Harvard University combined behavioral experiments with brain imaging using larval zebrafish as a model organism. Zebrafish larvae are small, transparent vertebrates with roughly 100,000 neurons. With current imaging techniques, the entire volume of the zebrafish larval brain can be imaged non-invasively at high resolution over many hours. 

The researchers saw that when zebrafish larvae were exposed to whole-field visual drift, they swam in the direction of the motion to stabilize themselves with respect to the visual environment. However, larvae don’t swim continuously. They make discrete movements that can each be considered an individual decision, raising the hypothesis that larvae accumulate evidence of the direction of the drift during motionless periods.

A popular decision-making paradigm (originally applied to humans and primates) is the random-dot motion discrimination task, which tests a viewer's perception of motion and direction. Using an adapted version of this random-dot paradigm, the scientists found that zebrafish larvae indeed accumulate information about motion direction over time and robustly swim in the direction they perceive their surroundings to be moving.

Further, the scientists created a whole-brain functional map and identified three clusters of neurons that relate to the behavioral choices of the zebrafish during the random-dot task. They propose a biophysical neural network in which a cluster of neurons, that integrates evidence of perceived motion direction over time, competes with another neuron cluster that represents a decision threshold. These two neuronal clusters are in a push-pull dynamic until a certain threshold is reached to finally activate the third cluster of motor neurons, which initiates movement in perceived direction.

With these findings, the researchers have shown for the first time that larval zebrafish integrate sensory information over time and that larvae are a suitable model organism to study questions about perceptual decision-making.

With electrical signals zapping at speeds up to 288 km/h (180 mph), neurons are the most well-known cells in the central nervous system. They are the basic unit of  information processing. Neurons transmit electrical signals to each other in neuronal circuits through junctions called synapses, and these junctions are formed between protrusions called spines. 

The break down of synapses in large numbers can lead to cognitive decline. Multiple Sclerosis (MS) is one such debilitating disorder of the nervous system, which causes alternating phases of inflammation and recovery. The synapses of people with MS are destroyed progressively over time. But it is still unclear how and why this synapse loss occurs. 

To better understand this process, a team of researchers at the Ludwig-Maximilians University in Germany injected inflammation-inducing factors into the brains of mice, to mimic MS as seen in humans. They looked at the brains of live mice across days using advanced light microscopy. Three days after the injection, during the inflammation phase, they saw widespread loss of a certain subset of synapses. As a result, neurons were not firing as actively as they should have been. However, once those synapses were re-established two weeks after injection, during the recovery phase, the neuronal activities of the mice were back to normal. 

The researchers wanted to know why were only a certain subset of synapses lost, and how that occurred. To answer this, they tracked the spines on the neurons over time using calcium sensors. They found that spines with high levels of accumulated calcium were unstable. Then they identified a special immune cell, called a phagocyte, that sniffed out and ultimately removed the synapses on these unstable spines. When they blocked the activation of these phagocytes using inhibitor drugs, they saw that it prevented the loss of synapses.

This study helps uncover one of the mechanisms underlying the loss of synapses during MS, albeit in mice. And, importantly, they have identified a therapeutic target for drug development that may address the decline of cognitive abilities in people with MS and ultimately improve their quality of life.

Mathematicians are human, just like the rest of us, which means that they sometimes make mistakes. As their work is read by other mathematicians, both during peer review and after publication, we might expect errors to be quickly spotted and addressed. But a fatal mistake in Alfred Kempe's 1879 "proof" of the Four Color Theorem remained unnoticed for over a decade.  The error was finally uncovered by Percy Heawood in 1890. 

The Four Color Theorem states that for any map of contiguous countries drawn on a plane only four colors are needed to ensure that adjacent countries are given different colors. In the heart of his “proof,” Kempe had to consider a number of different cases of possible map configurations.  To tackle these cases, he invented a new mathematical tool called Kempe chains. However Heawood discovered that Kempe's treatment of one of these cases didn’t work and presented an example to show how his reasoning failed.

Heawood's discovery did not mean that all was lost, though. First, Heawood showed that Kempe's work was enough to establish a weaker result called the Five Color Theorem which says that only five colors are needed to color a map in the required way.  Second, although Kempe's proof was flawed, the Four Color Theorem was true. It was first proved successfully, though somewhat controversially, using a computer by Kenneth Appel and Wolfgang Haken nearly a century later in 1976. And Kempe’s ideas played a significant role in their work. So while Kempe made a mistake in his “proof,” it still contained valuable mathematics.

Imagine yourself underwater with hundreds of fish schooling and swirling around you. What does that place look like?

Chances are, you imagined yourself on a tropical coral reef, the well-known, fish-friendly habitat often found in movies and vacation daydreams.

Think instead of being high atop an underwater mountain called a seamount. Despite their small habitat area and isolation from land, it turns out seamounts can host high numbers and diversity of fish species compared to nearby reefs, according to a recent study in Papua New Guinea published in the journal Coral Reefs. The researchers found that submerged pinnacles had 3.7 times the average fish abundance and nearly twice the biodiversity as nearby shallow reefs. This is a particularly important finding as coral reefs near the shores are vulnerable to pollution, fishing, and other ecological problems.

So the next time you think of schooling fish, imagine them atop an underwater mountain oasis!

Green tea has long been believed to have a variety of health benefits. One of the most important benefits is the preventive and treatment effects against cancer, which are mainly attributed to polyphenolic compounds, such as epigallocatechin-3-gallate (EGCG), a powerful natural antioxidant found in green tea. 

The anti-cancer effect of EGCG has been extensively demonstrated in epidemiological, cell culture, and animal studies, as well as in clinical trials. However there has been limited success in clarifying how this anti-cancer effect works at the molecular level, raising uncertainty about green tea’s value in cancer therapy.

The uncertainty was eased by a recent study, where scientists identified and validated a direct interaction between EGCG in green tea and the tumor suppressor protein p53, also known as “the guardian of the genome.” This interaction prevents p53 from degradation, meaning that EGCG has a protective effect for the tumor suppressor protein, which in turn guards cells against cancer. This work provides molecular insights into the mechanisms for EGCG’s anti-cancer activity and serves as strong evidence for the extraordinary benefit of consuming green tea. 

Methane is an important greenhouse gas in Earth’s atmosphere. Methane accumulates in oxygenated, surface freshwaters with high amounts of cyanobacteria. Cyanobacteria are photosynthetic bacteria, that grow using the same light-dependent, oxygen-producing process that plants use. However, the exact methane source in these environments are unknown, and many researchers believed that methanogenic archaea that live in anaerobic “pockets” or attached to cyanobacteria may be responsible for the methane produced in these waters.  

A recent study tested if cyanobacteria directly contribute to global methane budgets. The researchers grew 13 different kinds of cyanobacteria from various environments in the laboratory and fed them heavy carbon ("Carbon-13"). The heavy carbon was then incorporated into the cyanobacteria biomass, "labelling" the compounds that the cyanobacteria produced by making them heavier than usual. The researchers saw that methane was labelled with heavy carbon, even in cultures in which the cyanobacterium was the only organism present, which shows that cyanobacteria directly produce methane.

Because cyanobacteria blooms are expected to increase with global climate change, and methane is a potent greenhouse gas, the observation that cyanobacteria directly produce methane suggests that cyanobacteria blooms may be a previously unrecognized positive feedback loop on global climate change. However, the controls on methane production by cyanobacteria in the environment and the contribution of cyanobacteria to global methane budgets are still poorly understood.

Renewable energy is often seen as unwieldy or unreliable, but progress in climate-friendly tech suggests it could actually be more convenient. TEGs, or thermoelectric generators, can convert heat to electrical energy—and as a result, even body heat could be used to power small wearable electronic devices.

Unlike old TEGs which are rigid, the ones revealed in this study from Science Advances “can be bent without affecting power output.” They’re flexible and stretchy, which makes them practical tech for people to actually wear on their bodies.

Modeled after human skin, this kind of electronic skin, or e-skin is self-healing when damaged and has never before been combined with TEG power. Liquid metal and high-performance plastic allow pieces to connect like Legos, making the technology customizable.

Other features have been added to make this TEG more practical for everyday use: for example, a film on the outer “cold” side of the device is wavelength-selective, meaning it can handle light and heat from the sun well enough to still function during outdoor activities. 

New green energy technology is focused on ease of use, breadth of application, and possibility. This new TEG development suggests a future of energy-harvesting technology that’s easily adaptable, durable, high-performing, and eco-friendly.

Have you ever wondered if you would remember some information in the future? If so, you have made a judgment of learning (JOL). JOLs are part of our metamemory – our ability to reflect on our own memory. 

JOLs about how likely we will be to remember a certain word – for example, in the case of a student studying for a vocabulary test – depend on beliefs and knowledge we have about how word frequency impacts memory. They are also influenced by a subjective feeling of ease we might get from the word. And scientists have wondered, which is more important to JOLs: our beliefs about a word, or our experience with it? 

To clarify which factor better explains the effect of word frequency on JOLs, a group of scientists asked research study participants to make judgements of their personal learning before and after studying words. JOLs made before studying indicate the effects of the participants' beliefs only, but those made after indicate the effects of both their beliefs and their direct experience with the words.

 Previous research has shown that common words are more easily remembered than rare words. So, the scientists tricked participants and lead them to believe the opposite, by telling them that rare words on a list were common, and vice versa. They found that JOLs made after the participants encountered each word were consistently higher for common words, even when researchers had said the words were rare. This points to a person's experience as an important factor in their judgements of their learning.  

This line of research will help scientists understand how we make JOLs and to work on ways to improve people’s metamemories in different scenarios, such as learning new things.

Wallet, keys, phone, mask. Mask-wearing, a core and useful intervention to combat the raging pandemic, has become a daily habit for most people. It's also, however, raised concerns around kids' ability to understand emotions and social clues when surrounded by masked adults.

Psychologists at the University of Wisconsin-Madison explored this question of how well kids can identify anger, sadness, and fear among mask-wearers in a study of 81 US children aged seven to 13 years old published in PLoS ONE. Study participants made inferences about the emotions being conveyed in facial configurations of digital simulations of three types of faces: uncovered, wearing sunglasses, or wearing surgical masks.

Though children were best able to identify emotions in uncovered images 66 percent of the time, children were still able to successfully draw emotional inferences from facial configurations of mask wearers. This accuracy was also no more impaired by mask wearing than it was by sunglass wearing, with kids identifying emotions around 27 percent correctly in both cases.

Children's resilience, already supported by strong evidence in this study, is likely to be increased in real-world settings, where additional clues like vocal inflection and body language clue kids into what emotions to expect from others. The study suggest that kids are well able to adapt to mask-wearing without impediments to their growth and development.

Taking a stroll in the park can make us feel good. But, what about watching a movie about it? Although there is evidence that contact with nature improves our wellbeing, unfortunately not everyone can access the outdoors. Could virtual nature experiences be a solution?

A team of researchers from the University of Exeter and the University of Surrey set out to test whether exposure to virtual nature could improve one’s mood and alleviate boredom. First, the participants (96 adult volunteers) performed a boredom-inducing task, watching a four minute video where a man talked in a monotone voice about his office work. Afterward, they were exposed to virtual nature by watching five minutes of a documentary about coral reefs on either a high-definition 2D television, a 360º virtual reality video on a headset, or an interactive computer-generated virtual reality experience similar to the video versions on a headset with hand-held controllers. The researchers assessed the participants' moods and feelings before and after their contacts with virtual nature.

All three types of virtual exposure to nature reduced negative feelings, had a positive effect in the mood and increased feelings of connectedness to nature. While all settings were equally good at reducing bad feelings, the interactive virtual reality inspired the greatest positive feelings. 

The researchers point out, their results can be a first step to prepare for further analysis in “real” boring settings, such as hospitals or care homes. And, as many of us are facing lockdowns, we may keep in mind that nature documentaries can be a good companion — fancy virtual reality headset not required.

Many of us are familiar with the itchiness that can accompany an allergic response, along with the urge to scratch when we know we shouldn’t. Scientists are now one step closer to understanding what triggers such allergic responses.

Dendritic cells (DCs) are white blood cells that patrol the body on the look-out for foreign antigens that might pose a threat. Upon detecting a potential threat — sometimes a harmless allergen — certain DCs in the skin can become activated and migrate to the lymph nodes where they interact with T cells in order to initiate an allergic immune response. 

DCs can detect potential invaders using receptors on their surface. However, in a paper recently published in Immunity, researchers from Massachusetts General Hospital and Harvard Medical School found that allergy-initiating DCs isolated from mice did not become activated in response to model allergens, suggesting there must be other factors required for their activation and subsequent migration in living systems.  

Suspecting that the culprit was sensory neurons in close proximity to these DCs in the skin, the researchers injected mice with a chemical that blocks the function of sensory neurons and found that it prevented an allergic response. Furthermore, they showed that certain sensory neurons release a neuropeptide called Substance P in response to allergens. And when Substance P was injected into mice, it caused DCs to move to their lymph nodes, leading to an allergic response. 

Not only does this finding highlight the importance of looking at immune responses both in isolation and within living organisms, the discovery of the role of sensory neurons and Substance P in allergic responses identifies a potential target for allergy medications.

Dark matter makes up almost 30% of our universe, yet we still aren’t sure exactly what it is. One suggestion is that dark matter is made up of primordial black holes (PBHs), black holes formed in the very early universe. 

Usually, we think of black holes as forming from the deaths of the largest stars — but these PBHs had to be created before stars existed in the universe. A new model from researchers at UCLA shows a way that PBHs could have formed so that they explain all the dark matter observed in the universe.

This model builds on the Standard Model of particle physics, which describes how different particles and forces are related to each other, by adding only one additional term to its equations. In the early universe, particles coalesced together into massive halos, which could possibly collapse to make PBHs. The problem, though, is that in order for these halos to collapse, they’d need to get rid of some of their energy. This updated model describes a way for halos to radiate away that energy, meaning PBHs are, indeed, possible.

The model suggests that if PBHs are small, they could be abundant enough to explain all the mass of dark matter we see. If PBHs are large, they might not be able to explain all of dark matter, but they could still explain a fraction of it and even be detected by LIGO, the Laser Interferometer Gravitational Wave Observatory — meaning we could someday have concrete evidence for them.

Disclaimer: This research is by one of the author's colleagues.

Projecting film onto the ceiling of an indoor tent is a fun summer evening activity. It was also a laboratory setup at Johns Hopkins in the 1960s. What’s more exciting is that this setup led to a body of work that netted the tent-pitchers a Nobel Prize. Their finding in the tent is taught in all introductory neurobiology textbooks - the existence of cells sensitive only to particularly oriented lines. And it was all an accidental discovery that took place under these covers. 

These experiments began with a cafeteria meeting in 1959, where David H. Hubel met Stephen Kuffler and Torsten Wiesel. After confirming their interests in studying visual information processing in a superficial layer of the brain (the cortex), Hubel and Weisel set up their tents in Kuffler’s laboratory. 

Their experiments involved cats looking at the ceiling of this small indoor “circus arena,” where dark or light dots were projected while monitoring the activity of a single neuron. Their goal was simple: to understand what visual pattern activated these neurons. They used dots, drawn on glass slides to make the projection equipment work, since they knew they reliably stimulated retinal cells in the cats' eyes. After weeks of experiments, with various mishaps including accidentally spraying themselves with formalin (similar to formaldehyde), they triggered an avalanche of neuronal activity. 

Next to the projected dots was a shadow line cast from the edge of the glass slide the dots were drawn on. This line, an accidental stimulus rising from imprecise slide placement, revealed the existence of orientation sensitive cells, or cells that respond only to lines in certain angles, also sometimes called “simple cells.” Soon, they also found “complex cells,” neurons that responded to lines moving in a particular direction or having directional selectivity. (Their use of “simple” and “complex” highlight the increase in information processing as information passes through the brain, as simple cells are thought to send information to complex cells.) 

Hubel and Wisel paved the path for studying how the brain processes information. Their names and their work are revered in neurobiology, but their laboratory adventures and beneficial mishaps are less often remembered. 

Dating back to the drawings of Ramon y Cajal, neuroscientists have always been fascinated with the striking shapes of neurons. Today, scientists still rely heavily on microscopy—albeit with instruments far more advanced than those in 1900—in hopes of understanding how neurons work by visualizing these fantastic cells. As new imaging techniques and approaches develop, we are able to learn more and more about neurons and the brain as a whole.

The beautiful shape of a neuron is intrinsically linked to its function. If the branched dendrite of one neuron contacts the long slim axon of another neuron, a connection (synapse) may form between them. When a neuron is stimulated, little packets of neurotransmitters called vesicles are released at the synapse. Then, the neurotransmitters are taken up by the second neuron, affecting its own activity. 

This process occurs continuously in the billions of neurons and trillions of synapses that make up the human brain. With these astounding numbers, how can scientists zoom in and understand how specific neurons function, let alone specific synapses?

A new study published in Nature used a trio of impressive techniques to help answer this question. By optimizing a combination of light microscopy, electrophysiology, and electron microscopy, the researchers were able to measure the activity and image the ultra-structure of synapses in a mouse brain.

They observed numerous instances of axons and dendrites from different neurons touching, suggesting synapses were at these contact sites. However, when they took ultra-structure images of these neurons by electron microscopy, they noted synapses only formed at a percentage of the contact sites.  

In examining the synapses that did form, the researchers made two novel observations. First, they showed that the size of synapse correlated with the electrical activity of the neuron. They also determined numerous vesicles could be released at the synapse simultaneously, contradicting the previous belief that only one vesicle was released at a time.

This combination of various methodologies to study the same synapse opens the door for future work to further probe the relationship between neuronal structure and activity, ultimately helping the scientific community better understand how synapses form and are regulated.

Proteins are the fundamental components of virtually everything occurring within our bodies – but what happens when the machines that make proteins become defective? 

These protein-making machines are called ribosomes and mutations in ribosomes are connected to a group of human disorders called ribosomopathies. However, it remains unclear, at a cellular level, why defects in ribosomes cause problems in our bodies. This is where the use of model organisms such as fruit flies for research purposes is particularly valuable.

In a recent study, scientists used the fruit fly as a model to study the cellular basis of ribosomapathy. The scientists introduced a mutation previously reported from a human patient into the fruit fly ribosome. The resulting flies were developmentally delayed, and had much shorter hairs than normal.

In looking at the fruit fly cells, the researchers found that proteins that were not produced properly built up and formed aggregates. Proteins have to be folded into the correct 3D structure to perform their functions; and cells have an in-built system to remove any misfolded protein. But when ribosomes cannot operate normally due to a mutation, defective ribosomal products build up and can place an unusually large burden on the cell’s protein degradation system – a phenomenon called proteotoxic stress.

This finding opens up promising avenues for future therapeutics. The scientists proposed that this proteotoxic stress can be relieved by boosting the removal of toxic waste from cells (a process called autophagy), as well as combining with treatments that enhance protein production quality. Similar interventions have already been considered for diseases that involve protein aggregates, such as Alzheimer’s disease and Huntington’s disease.

Disclaimer: This paper was performed in the author's current lab group, but they were not involved in the research.

 MC Hammer recently brought the hammer down on those who see science and philosophy as fundamentally opposed disciplines.  He first tweeted a link to this paper, showing that STEM fields account for 21.3% of citations of philosophy of science journals.  Some tweeters responded with unflattering, and inaccurate, characterizations of philosophy that put it at odds with science.  In response, MC Hammer had some words of advice praised by scientists and philosophers alike: "It's not science vs Philosophy ... It's Science + Philosophy. Elevate your Thinking and Consciousness. When you measure include the measurer."

MC Hammer's insistence on the complementary nature of science and philosophy is in line with this 2019 opinion paper, published in PNAS.  The authors described a continuum of science and philosophy, as the two fields share "the tools of logic, conceptual analysis, and rigorous argumentation.”  They also provided three concrete examples of how philosophy helped scientific research in the life sciences and concluded with six practical proposals to encourage collaboration between scientists and philosophers.  

Tweets by MC Hammer promoting these views will hopefully also help to break down harmful stereotypes of the disciplines that might prevent scientists and philosophers from working together for the good of society.

Self-care is a term that has gained immense momentum in the past year, in an era where most people have been stripped of their previous coping mechanisms and left to explore new ways to handle stress. Hearing this mantra may conjure up images of a face mask treatment, yoga sessions, or movie marathon, but in reality it is much more complex.

Although self-care boasts a history of blurry definitions in the past, the term actually grew out of the nursing field and a model called Orem’s Self Care Model. It encompasses both the intent and knowledge to care for one’s health, as well as the activities performed to accomplish this goal. A current model called the Seven Pillars of Self-Care framework categorizes self-care activities such as physical activity, healthy eating, and good hygiene.

Yet, self-care remains difficult to quantify. Pre-existing studies and frameworks have failed to provide an effective way to screen self-care activities, both in and outside of COVID-19 times. Developing this screening would help identify who is most likely to do self-care, and the activities they engage it. It is of utmost importance in an era where mental health issues and lack of holistic health care are as widespread as the virus itself.   

In their pursuit to test existing screenings to develop an improved self-care screening method, a research team in Spain has developed a survey called the Self-care Activities Screening Scale (SASS-14) to measure self-care activities among Spanish-speaking populations during COVID-19. Because their survey is specific to the pandemic, they were able to recommend that screening for self-care during periods of extended lockdown should focus on physical care, nutrition, sleep, and emotional health.

As a result of this research, the SASS-14 is available as an online tool for healthcare workers to use to monitor how people are taking care of themselves during the extended lockdowns and lack of social contact that we are all experiencing.

Last week, NASA’s Perseverance rover safely landed on Mars. In the days since, the science team has been checking the rover’s systems to make sure it is working and ready to explore, and they’ve also received Perseverance’s first images of the Martian surface. Even cooler, they recently released the first sounds (ever!) from Mars and the first video of a spacecraft landing on the red planet.

Unlike earlier Mars missions (Sojourner, Spirit and Opportunity), which landed on giant airbags, Perseverance and its predecessor Curiosity landed using a “sky crane” system, where a rocket-powered crane gently lowers the rover down to the surface. The Mars Reconnaissance Orbiter (MRO) also captured a bird’s eye view of the landing, plus where all the various descent stages (heat shield, parachute/back shell, and sky crane) ended up across the surface.

Perseverance and its landing gear were uniquely equipped with a microphone and six cameras to capture the various angles of the entry, descent, and landing process. In the incredible video of Perseverance’s landing, you can see the parachute launched by a small explosive, the first step in slowing down the spacecraft. This parachute had a hidden easter egg from the engineering team, too—its color pattern reveals the JPL motto, “Dare Mighty Things.” After the parachute deployed, the spacecraft gently rocked back and forth until the back shell separated and the sky crane's engines kicked in, steering the rover toward its landing spot. 

The rover approached the surface, obscured by dust kicked up from the sky crane’s rockets. Once it touched down, the last frames of the video reveal the sky crane cutting the wires attaching it to the rover, then flying away to land elsewhere on Mars, safely away from the rover. Post-landing, Perseverance’s microphone captured the sound of a gusty wind accompanied by the constant buzz of the rover itself.

So, what comes next for Perseverance? The mission team will continue checking out the hardware to make sure all systems are working properly, and will soon take the rover for its first drive on the Martian surface. It landed near a variety of different geologic features scientists are eager to explore, including an ancient river delta already spotted in Mastcam-Z’s incredible panorama. (Note: The “Z” is for zoom, so we can certainly expect more stunning photos.) There’s so much exciting science to come as Perseverance explores Mars looking for signs of life!

Humans are diurnal – we are active during the day and sleep at night. Our circadian rhythms are in sync with the sun, the strongest source of light on the planet. However, recent evidence suggests that moonlight may also influence our sleeping patterns, and this effect changes with the lunar cycle.

"We hypothesize that the patterns we observed are an innate adaptation that allowed our ancestors to take advantage of this natural source of evening light that occurred at a specific time during the lunar cycle," said Leandro Casiraghi, lead author of a new study, published in Science Advances.

The research, a collaboration between the University of Washington, Yale University, and the National University of Quilmes in Argentina, assessed the activity patterns of 562 participants across an urban-rural gradient. Participants included members of three Indigenous Toba/Qom communities in Argentina and undergraduate students from the University of Washington. Each participant slept with a wristwatch that tracked their movement and sleep. This data was combined with NASA's sun and moon data for each location.

The researchers found that the time the participants went to sleep and how long they slept oscillated during the course of the lunar cycle. On nights leading up to a full moon, when the moon was brighter, people went to sleep later and slept for a shorter time. 

The researchers concluded that moonlight stimulates nocturnal activity, especially for those in rural communities where light pollution is sparse. People in cities, with greater light pollution, went to sleep later and slept for less time in general, but still followed similar patterns to people living with little or no access to artificial light. The researchers state that the artificial light present in cities mimics the effect that moonlight has on sleep for rural communities. 

So next time you are having trouble falling asleep, you may want to look to the moon for an explanation.

There are many organisms such as spiders, lizards, and even starfishes (and many more) who voluntarily shed or detach a body part, also known as autotomy. They do so for several reasons. For example, autotomy is an escape strategy (for instance, if a leg is trapped between two rocks). It can also be a distraction for predators — an amputated tail wriggles, and makes a predator look one way while the tail shedder runs the other. Sometimes organisms self-amputate wounded limbs. 

In a nutshell, autotomy enhances survival. However, it may also impose some costs.

Recently, scientists tested if this survival strategy incurs any reproductive costs in a scorpion species, Ananteris balzani. The scorpion sheds its tail permanently, causing the loss of the anus and a lifelong inability to poop. Male scorpions also use their tails during mating. 

However, the researchers showed that tail loss has no effect on male mating success when compared to males with a tail. Remarkably, a tail-less female had less of babies than females with tails. This interesting finding suggests that the negative effect of “taillessness” is sex-dependent, and in these scorpions it is the females that pay the cost.

The US residential power supply system is messed up at all times, but Texas's power supply is particularly problematic right now. And worse, it's about to be crushing financially for millions of families impacted by winter weather, especially the families that are poor, or elderly, or not white (or all three).

Because many states have deregulated their power markets, a lot of people get their power through retail energy suppliers. These companies are, essentially, energy arbitrage firms. They spend a lot of time and money analyzing weather and usage and production to decide how much power to buy for their customers, and how much to charge for that power. They usually make sure that their costs are significantly below the rate they offer customers — that's how they make money. Except for when something unexpected happens, like an extreme weather event. 

Right now, for a lot of reasons, energy providers don't have access to a lot of power to purchase, and the massive winter demand coupled with huge supply problems are causing the wholesale price of power to skyrocket from $50 per megawatt-hour to over $9,000 per megawatt-hour. 

But these retail energy suppliers still need to make money, so how do they make up this ginormous deficit? They charge people more for the power! They might be able to legally add a surcharge to your bill in some areas, or they might adjust rates next year. The easiest thing to do, though, is just charge people more - and the consumers they can charge more are the consumers with variable-rate plans (VRP).

There can be a lot of good reasons to choose a variable rate plan, but there are also a lot of bad reasons to choose (or be assigned) a VRP. Sometimes a VRP is all that's available to a consumer (they have bad credit, they can't afford to put a deposit down for a contract with a fixed rate), or it's assigned to a consumer. Much like credit card companies, if you miss a payment, energy suppliers can put you in the metaphorical penalty box by charging you interest on your overdue balance while also raising your rates - penalty plans are often variable rate plans. 

Sometimes people end up with a VRP because of an information asymmetry — for example, when an elderly person signs up for a bad plan because it was incorrectly recommended or the first option offered, or when someone with limited English proficiency or literacy deficits doesn't understand their options.

After the 2014 polar vortex, households on VRPs experienced astronomical bills. In some areas, the cost of electricity jumped to $2 per kWh. For context, the average cost of residential electricity was $0.125 per kWh in 2014. In Chicago, one 72-year-old man reported that his monthly bill jumped from $81 to over $300. 

That's why marginalized people are likely to be extra financially burdened by this storm. They are more likely than average to be on VRPs.

This winter weather is bad news for everyone - people are dying, people don't have power in frigid conditions. This weather crisis has the potential to be financially disastrous for families, on top of the costs of repairs from weather damage. Help these families by donating to charities that assist with paying heating and electric bills, demanding accountability from lawmakers and energy regulators, and taking steps to stop climate change so these storms don't get worse every year. 

If you have power right now, you can help these households by trying not to use your power. Rationing is effective against blackouts, but it also helps drive down demand, and thus cost. 

Natural light is thought to be one of essential environmental factors dictating the ways animals live their lives. In aquatic animals, like coral larvae, the intensity and color of the light can be a crucial factor associated with swimming and moving behavior.

A new research study by a team of Japanese researchers, published in Scientific Reports, has explained how Acropora tenuis (a common reef coral) larvae move through the deep sea in response to the light intensity and color. 

Coral larvae are the free-moving life stage of corals, and they build colonies of the things that we think of as reef corals. The researchers found that these coral larvae swim slower in deeper water where there is less light, and that blue light is a particularly important cue for swimming. This is remarkable, since larvae lack eyes, yet they can still sense light intensity and color. The researchers suggest that this behavior could help the larvae locate habitat with the bright and blue wavelengths of light they need as adults. 

This behavioral phenomenon in coral larvae provides a more fundamental understanding of the early phases of larval settlement coral reefs in the natural environment.

In what is perhaps the most "2020" study, a group of researchers from the United States and Denmark (with the help of community scientist-bakers across the globe) have studied the biodiversity contained within 500 sourdough starters. Their research was recently published in the journal eLife. 

The researchers collected 500 sourdough starters. These came mainly from the United States and Europe, but also included contributions from New Zealand, Thailand, and Australia. 

All 500 sourdough samples were DNA-sequenced to determine their microbial makeup. They then took 40 samples that represented the range of diversity and tested them for aroma profiling, chemical analysis, and rising speed. They discovered that an until-now overlooked component of microbial diversity, acetic acid bacteria, play a significant role in sourdough's aroma and rising speed.

As an observational study, the results do not give us a master recipe for exactly which microbes create which bread characteristics. But the study does show that the types of microbes in a sourdough started affects how it rises, smells, and bakes. If you are still pandemic-baking, rest assured that there is plenty more fun to be had in determining the exact role of the microbes found in sourdough.