New study reveals how blood triggers brain disease

 In patients with neurological diseases like Alzheimer's disease and multiple sclerosis, immune cells in the brain known as microglia that normally fulfill beneficial functions become harmful to neurons, leading to cognitive dysfunction and motor impairment. These harmful immune cells may also contribute to age-related cognitive decline in people without dementia.

For some time, scientists have been trying to better understand the triggers responsible for turning good microglia bad, and their exact contribution during disease. If they could identify what makes microglia toxic, they could find new ways to treat neurological diseases.

Now, researchers  showed that exposure to blood leaking into the brain turns on harmful genes in microglia, transforming them into toxic cells that can destroy neurons.

The scientists discovered that a blood protein called fibrin—which normally aids blood clotting—is responsible for turning on the detrimental genes in microglia, both in Alzheimer's disease and multiple sclerosis. The findings, published in the journal Nature Immunology, suggest that counteracting the blood toxicity caused by fibrin can protect the brain from harmful inflammation and loss of neurons in neurological diseases.

Individuals with neurological diseases like Alzheimer's disease and multiple sclerosis have abnormalities within the vast network of blood vessels in their brain, which allow blood proteins to seep into brain areas responsible for cognitive and motor functions. Blood leaks in the brain occur early and correlate with worse prognosis in many of these diseases.

In the new study, the researchers found that different blood proteins activate distinct molecular processes in microglia. What's more, they identified that fibrin is responsible for driving unique gene and protein activities that make microglia toxic to neurons. The other blood proteins tested were not mainly responsible for these toxic effects.

https://www.nature.com/articles/s41590-023-01522-0

Using Nanoparticles to Combat Antibiotic Resistance Bacteria

People who preserve 'immune resilience' live longer and resist infections, study finds

Researchers have revealed that the capacity to resist or recover from infections and other sources of inflammatory stress—called "immune resilience"—differs widely among individuals. The researchers developed a unique set of metrics to quantify the level of immune resilience. This will aid in decisions for health care and help researchers understand differences in life span and health outcomes in persons of similar ages. 

Although age plays an important role in the body's response to infectious and other inflammatory stressors, some persons preserve and/or restore optimal immune resilience regardless of age.

Immune resilience is the capacity to maintain good immune function, called immunocompetence, and minimize inflammation while experiencing inflammatory stressors. 

Researchers found that during aging and when experiencing inflammatory stress, some persons resist degradation of immune resilience.

individuals with optimal levels of immune resilience were more likely to:

• Live longer.
• Resist HIV and influenza infections.
• Resist AIDS.
• Resist recurrence of skin cancer after kidney transplant.
• Survive COVID-19 infection.
• Survive sepsis.

Part 1

One consistent finding throughout the populations studied was that age was not the single determinant factor in a person's response to inflammatory stress. Some younger persons with poor immune resilience had the same signatures and immune health grades commonly seen in older persons. This finding suggests that the ability to restore and maintain immunocompetence at younger ages may be linked to life span. Another factor noted across the populations and species was that higher levels of optimal immune resilience were observed more often in females than males.

These assessments have utility for understanding who might be at greater risk for developing diseases that affect the immune system, how individuals are responding to treatment, and whether, as well as to what extent, they will recover.

Sunil Ahuja, Immune resilience despite inflammatory stress promotes longevity and favorable health outcomes including resistance to infection, Nature Communications (2023). DOI: 10.1038/s41467-023-38238-6. www.nature.com/articles/s41467-023-38238-6

Part 2

 How microplastics stick around in human airways

Research shows humans might inhale about 16.2 bits of microplastic every hour, which is equivalent to a credit card over an entire week. And these microplastics—tiny debris in the environment generated from the degradation of plastic products—usually contain toxic pollutants and chemicals.

Inhaled microplastics can pose serious health risks, so understanding how they travel in the respiratory system is essential for prevention and treatment of respiratory diseases.

Researchers  explored the movement of microplastics with different shapes (spherical, tetrahedral, and cylindrical) and sizes (1.6, 2.56, and 5.56 microns) and under slow and fast breathing conditions.

Microplastics tended to collect in hot spots in the nasal cavity and oropharynx, or back of the throat.

The complicated and highly asymmetric anatomical shape of the airway and complex flow behavior in the nasal cavity and oropharynx causes the microplastics to deviate from the flow pathline and deposit in those areas.

The flow speed, particle inertia, and asymmetric anatomy influence the overall deposition and increase the deposition concentration in nasal cavities and the oropharynx area.

Breathing conditions and microplastic size influenced the overall microplastic deposition rate in airways. An increased flow rate led to less deposition, and the largest (5.56 micron) microplastics were deposited in the airways more often than their smaller counterparts.

This study emphasizes the need for greater awareness of the presence and potential health impacts of microplastics in the air we breathe.

How microplastics are transported and deposited in realistic upper airways, Physics of Fluids (2023). DOI: 10.1063/5.0150703

How cells kill themselves

Researchers  artificially re-creates cell 'skeletons' using strands of DNA

Seeing Dead Flies Makes Other Flies Die Faster

There might be a weird benefit to leaving dead flies where they fall .

Research has shown that when fruit flies of the species Drosophila melanogaster are exposed to the carcasses of their dead friends, their lifespan shrinks in a significant and measurable way.

They start acting withdrawn, lose body fat, and their aging accelerates to the point that they die sooner than fruit flies that don't see their dead buddies just lying where they fall like some macabre fruit fly graveyard.

And now scientists have a better idea about why this happens. Two neuron types receptive to the neurotransmitter serotonin become activated when fruit flies perceive dead comrades, and this increased activity accelerates the flies' aging process.

Scientists have seen similar effects in other animals: necrophoresis, or the removal of dead conspecifics, in eusocial insects; vocalization and corpse inspection in elephants; or an increase in levels of regulatory hormones called glucocorticoids in nonhuman primates.

https://journals.plos.org/plosbiology/article?id=10.1371/journal.pb...

Right-handed building blocks of life

Scientific research may have solved the puzzle of how life became molecularly right-handed. In the paper, "Origin of biological homochirality by crystallization of an RNA precursor on a magnetic surface," published in Science Advances, the researchers explain how it all might have started with the right kind of rocks.

Molecules can be left-handed, right-handed or both. RNA and the sugars that makeup DNA are right-handed molecules. Nobody knows why or if there is a reason beyond chance that life started right-handed.

As an analogy, human hands can be left or right, and they are mirror images of each other, which means that they cannot be superimposed without one facing the wrong way. Molecules can have similar structural symmetry.

In much the same way that right-handed people have difficulty with left-handed scissors, or left-handed guitar players need to reverse strings and play the instrument the other way round, molecules do not interact the same way when they are left or right-handed. Once started, it makes sense that the building blocks of life should continue with the same handedness.

One intriguing idea is that cosmic rays with left-handed spin destroyed left-handed DNA precursors just as life started on Earth.

Ribo-amino oxazoline (RAO) is a crucial RNA precursor for two of RNA's nucleotides, cytosine and uracil. RAO also happens to form a crystalline structure that can be either right-handed or left-handed that, once the crystal starts forming, right or left, only binds with other molecules of the same handedness.

By placing RAO on magnetite (Fe₃O₄) surfaces, researchers could achieve 100% handedness of RAO crystallization, either left or right, depending on the spin-exchange interaction and degree of spin alignment (magnetization) at the active surface.

Earth's most abundant natural magnetic mineral, magnetite, would have had plenty of interaction opportunities with RAO in primordial times. However, the researchers say the effect is not likely to occur in particle solution contact like mud but rather on sedimentary rock surfaces.

Even with the current findings possibly unlocking two of the four RNA nucleotide components, two more are still missing. So far, The origin story finds that common, naturally occurring components at room temperatures can start the process. If the next two are found to have similar requirements, it would indicate that life on any Earth-like planet in the universe could have started just as easily.

S. Furkan Ozturk et al, Origin of biological homochirality by crystallization of an RNA precursor on a magnetic surface, Science Advances (2023). DOI: 10.1126/sciadv.adg8274

S. Furkan Ozturk et al, Chirality-Induced Magnetization of Magnetite by an RNA Precursor, arXiv (2023). DOI: 10.48550/arxiv.2304.09095

New research shows illusions are in the eye, not the mind's neurons

Numerous visual illusions are caused by limits in the way our eyes and visual neurons work—rather than more complex psychological processes, new research shows.

Numerous visual illusions are caused by limits in the way our eyes and visual neurons work—rather than more complex psychological processes, new research shows.

The new study suggests simple limits to neural responses—not deeper psychological processes—explain these illusions.

Our eyes send messages to the brain by making neurons fire faster or slower. However, there's a limit to how quickly they can fire, and previous research hasn't considered how the limit might affect the ways we see color.

The model combines this "limited bandwidth" with information on how humans perceive patterns at different scales, together with an assumption that our vision performs best when we are looking at natural scenes.

The model was developed by researchers from the Universities of Exeter and Sussex to predict how animals see color, but it was also found to correctly predict many visual illusions seen by humans.

Part 1

Modern high dynamic range televisions create bright white regions that are over 10,000 times brighter than their darkest black, approaching the contrast levels of natural scenes.

How our eyes and brains can handle this contrast is a puzzle because tests show that the highest contrasts we humans can see at a single spatial scale is around 200:1.

Even more confusingly, the neurons connecting our eyes to our brains can only handle contrasts of about 10:1.

This new  model shows how neurons with such limited contrast bandwidth can combine their signals to allow us to see these enormous contrasts, but the information is 'compressed'—resulting in visual illusions.

The model shows how our neurons are precisely evolved to use of every bit of capacity.

"For example, some neurons are sensitive to very tiny differences in gray levels at medium-sized scales, but are easily overwhelmed by high contrasts.

"Meanwhile, neurons coding for contrasts at larger or smaller scales are much less sensitive, but can work over a much wider range of contrasts, giving deep black-and-white differences.

"Ultimately this shows how a system with a severely limited neural bandwidth and sensitivity can perceive contrasts larger than 10,000:1."

Endometriosis could be caused by bacteria

Endometriosis could be caused by Fusobacterium. The severely painful condition, in which tissue similar to the uterus lining grows outside the uterus, affects up to 10% of women. In a study of 155 women, the bacterium was found in around 64% of those with endometriosis a.... Experiments with Fusobacterium-infected mice showed that antibiotics could reduce the size and frequency of the lesions that are associated with the disease. A clinical trial is now under way to find out whether antibiotics could relieve some endometriosis symptoms.

https://www.science.org/doi/10.1126/scitranslmed.add1531

https://www.nature.com/articles/d41586-023-01956-4?utm_source=Natur...

Study finds that the human brain reactivates mental representations of past events during new experiences

Neuroscience studies have showed that as mice and other rodents navigate a maze, their brain often "replays" relevant past events. This mental replaying of events, such as the route taken until reaching their current position, could help rodents create a mental map of the spatial environment, and understand their position in it.

Researchers  recently explored the possibility that the human brain also replays past events to make sense of evolving, non-spatial experiences. Their findings, published in Nature Neuroscience, confirms this hypothesis and suggests that the process through which the human brain reactivates these events might be far more complex than that observed in rodents.

Researchers tried to devise an experiment that might elicit the replay of past events as observed in rodents, but during non-spatial daily experiences. Ultimately, they decided to ask their participants to watch a movie or listen to audio recordings of a narrated story while recording their brain activity using a functional magnetic resonance imaging (fMRI) scanner.

Movies and stories simulate real world experiences, as they are composed of events that should be linked together to understand the overall narrative.

Interestingly, researchers  found that as participants were engaged in the narrative of a movie or story, representations of past events, which were needed to make sense of each present scene, were reactivated in their brain. Unlike in rodents, these reactivations appeared while the participants were watching the movie or listening to the story, rather than during periods of rest from the task.

They found that the same brain regions that replay spatial information in the rodent brain also replay narrative events in the human brain. In other words, replay, previously thought to mainly support spatial navigation, could also underlie the human ability to make sense of narratives.  

Overall, the recent work by this team of researchers suggests that while humans are trying to make sense of their present experiences, their brain may continuously reactivate relevant past events. 

Avital Hahamy et al, The human brain reactivates context-specific past information at event boundaries of naturalistic experiences, Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01331-6

Scientists think disorienting the malaria parasite may prevent it from causing harm

With almost 250 million cases a year, 621,000 of them fatal, malaria remains a major public health problem, particularly in sub-Saharan Africa. Malaria is a parasitic disease transmitted by mosquitoes and caused by a microbe of the genus Plasmodium. On its journey from mosquito to human, Plasmodium must adapt to the specificities of the many organs and cells it parasitizes. Microbes do not have sensory organs; instead, they have sensors made of proteins to detect molecules specific to the environments they colonize. While most living organisms share the same types of sensors, Plasmodium is an exception.

Biologists have identified a new type of sensor that enables Plasmodium to know precisely where it is and what to do. This work, published in the journal Science Advances, opens up the possibility of scrambling the signals perceived by this sensor to disorient the parasite and thus prevent its replication and transmission.

When a human is bitten by a Plasmodium-infected mosquito, the parasite enters the bloodstream and travels to the liver, where it thrives for around 10 days without causing any symptoms. After this period, Plasmodium re-enters the bloodstream, where it parasitizes red blood cells. Once inside the red blood cells, the parasites multiply in a synchronized 48-hour cycle.

At the end of each multiplication cycle, the newly-formed parasites leave their host red blood cells, destroying them and infecting new ones. It is this destruction of red blood cells that causes the waves of fever associated with malaria. Severe forms of malaria are linked to the obstruction of blood vessels by infected red blood cells.

When a mosquito bites a human whose blood is infected with Plasmodium, the parasite changes its development program to colonize the intestine of its new host. After a further period of multiplication, Plasmodium returns to the mosquito's salivary glands, ready to infect a new human.

From the warmth of the red blood cell to the depths of the mosquito's intestine via the liver, how does Plasmodium perceive changes in its environment in order to change its development program? Understanding this very specific biological mechanism is an important step towards countering the parasite.

Part 1

At each stage of its life cycle, the parasite must logically pick up signals that enable it to react correctly.

There are small molecules  absent in the blood but present in the mosquito that the parasite is able to detect. Starting from this single known element, scientists have identified a sensor that enables the parasite to detect the presence of these molecules when it is ingested by a mosquito.

This sensor is made up of five proteins. In its absence, the parasite does not realize that it has left the bloodstream for the mosquito, and is therefore unable to continue its development.

Surprisingly, this sensor is also present at other stages of the parasite lifecycle, notably when the parasite has to leave the red blood cell. Scientists then observe exactly the same mechanism: without this sensor, Plasmodium is trapped in the red blood cells, unable to continue its infection cycle.

The protein complex discovered here is absent in humans, but is found in the entire family of apicomplexan parasites to which Plasmodium belongs, as well as Toxoplasma, the agent of toxoplasmosis. By identifying this sensor, scientists can now imagine how to scramble the signals perceived by the parasite at different stages of its development, thus disorienting it and blocking its multiplication and transmission.

Ronja Kühnel et al, A Plasmodium membrane receptor platform integrates cues for egress and invasion in blood forms and activation of transmission stages, Science Advances (2023). DOI: 10.1126/sciadv.adf2161. www.science.org/doi/10.1126/sciadv.adf2161

Part 2

NASA finds key building block for life in a moon of Saturn

Scientists have discovered that phosphorus, a key building block of life, lies in the ocean beneath the icy surface of Saturn's moon Enceladus. The finding was based on a review of data collected by NASA's Cassini probe, and was published Wednesday in the prestigious journal Nature.

Cassini started exploring Saturn and its rings and moons in 2004, before burning up in the gas giant's atmosphere when its mission ended in 2017.

NASA found abundant phosphorus in plume ice samples spraying out of the subsurface ocean.

Scientists previously found other minerals and organic compounds in the ejected ice grains, but not phosphorus, which is an essential building block for DNA and RNA, and is also found in the bones and teeth of people, animals, and even ocean plankton.

Simply put, life as we know it would not be possible without phosphorus.

It's the first time this essential element has been discovered in an ocean beyond Earth.

With this finding, the ocean of Enceladus is now known to satisfy what is generally considered to be the strictest requirement for life. The next step is clear –- we need to go back to Enceladus to see if the habitable ocean is actually inhabited.

Frank Postberg, Detection of phosphates originating from Enceladus's ocean, Nature (2023). DOI: 10.1038/s41586-023-05987-9. www.nature.com/articles/s41586-023-05987-9

Study finds combustion from gas stoves can raise indoor levels of chemical linked to blood cell cancers

A chemical linked to a higher risk of leukemia and other blood cell cancers creeps into millions of homes whenever residents light their gas stoves. A new Stanford-led analysis finds that a single gas cooktop burner on high or a gas oven set to 350 degrees Fahrenheit can raise indoor levels of the carcinogen benzene above those in secondhand tobacco smoke. Benzene also drifts throughout a home and lingers for hours in home air, according to the paper published in Environmental Science & Technology.

Benzene forms in flames and other high-temperature environments, such as the flares found in oil fields and refineries. We now know that benzene also forms in the flames of gas stoves in our homes. Good ventilation helps reduce pollutant concentrations, but it was found that exhaust fans were often ineffective at eliminating benzene exposure.

Overall, the researchers found that indoor concentrations of benzene formed in the flames of gas stoves can be worse than average concentrations from secondhand smoke, that benzene can migrate into other rooms far from the kitchen, and that concentrations measured in bedrooms can exceed national and international health benchmarks. They also found residential range hoods are not always effective at reducing concentrations of benzene and other pollutants, even when the hoods vent outdoors.

The researchers also tested whether foods being cooked emit benzene and found zero benzene emissions from pan-frying salmon or bacon. All benzene emissions the investigators measured came from the fuel used rather than any food cooked.

Part 1

How to reduce exposure to pollutants from gas stoves

Beyond ensuring proper ventilation with a range hood or open window, relatively low-cost approaches to reducing exposure to pollutants from gas stoves include:

• Use portable induction cooktops, which can be found for less than $50 new.
• Use electric kitchenware, such as tea kettles, toaster ovens, and slow cookers.
• Where available, take advantage of state and local rebates as well as low- or no-interest loans (such as these programs for California and the San Francisco Bay Area) to offset the cost of replacing gas appliances.
• Federal tax credits are available now, and federal rebates should be available later this year or sometime in 2024 to help offset the cost of replacing gas appliances.

Special Nasal Drops Could Help The Brain Recover After A Stroke

Scientists have demonstrated how nasal drops containing a particular molecule can help mice recover from the damaging biological consequences of a stroke – and the hope is that the treatment could eventually be transferred to humans.

Earth Could Feasibly Descend Into Chaos, Physicists Warn

The impact of human activity on the Earth system could result in unpredictable chaos from which there is no return, physicists have calculated.

Using a theory conceived to model superconductivity, a team of physicists showed that, after a certain point, we will not be able to restore equilibrium to Earth's climate. A finite amount of human activity could result in a Hothouse Earth from which there is no return. They detailed their work in a paper made available in April 2022 on the preprint server arXiv that remains to be peer-reviewed.

If the Earth System gets into the region of chaotic behavior, we will lose all hope of somehow fixing the problem, they warn.

For some years now, extreme weather events seem to be occurring more regularly. Wildfires blaze, storms rage, temperatures reach new records. Climate scientists have warned that this is a consequence of human activity, such as the burning of fossil fuels, deforestation, and increases in farming.

This has led to the proposal of a new geological epoch: the Anthropocene, a period in which human activity has led to a significant and marked impact on the entire Earth system, comprised of the geosphere, biosphere, hydrosphere, and atmosphere.

The Anthropocene would follow the Holocene, which started around 11,700 years ago, and scientists propose its beginning around the middle of the 20th century – the peak of the nuclear era.

Part 1

Phase transitions are very common. The term refers to how a material changes from one state to another. A solid melts into a liquid, a liquid boils into a gas. A metal transitions from a normal state to a superconducting one. Each of these has a tipping point at which an equilibrium state undergoes a profound shift into another state.

Their results showed that we're not necessarily headed for certain climate doom. We might follow quite a regular and predictable trajectory, the endpoint of which is a climate stabilization at a higher average temperature point than what we have now. That's… still not great, given the deadly effects we're already seeing on humans and other animals.

But at the more extreme end, Earth runs into havoc. This means that the Earth's system evolves into chaotic behavior – extreme seasonal fluctuations and weather events – that precludes prediction of the future behavior of the system, making it impossible to mitigate. That means it would be extremely difficult, if not impossible, to claw our way back to a stable climate.

Even for this simple case, we observed the emergence of chaotic behavior in the equilibrium points of the Earth system. This leads to potentially important consequences if at least some components of the human activities actually follow logistic maps, which is a quite reasonable hypothesis, given the physical limitations of the planet-wide system we live in."

This outcome isn't inevitable, which is something of a relief. But, the researchers say we need to consider it a real possibility for designing strategies to mitigate climate change and manage the Earth system in the future.

https://arxiv.org/abs/2204.08955

**

Part 2

Penguin propulsion: The physics behind the world's fastest swimming birds

Penguins aren't just cute: they're also speedy. Gentoo penguins are the fastest swimming birds in the world, and that ability comes from their unique and sophisticated wings.

Researchers  developed a model to explore the forces and flow structures created by penguin wings underwater. They determined that wing feathering is the main factor for generating thrust. Their findings have been published in the journal Physics of Fluids.

Penguin wings, aka flippers, bear some resemblance to airplane wings covered with scaly feathers. To maximize efficiency underwater instead of in the air, penguin wings are shorter and flatter than those of flying birds.

The animals can adjust swimming posture by active wing feathering (changing the angle of their wings to reduce resistance), pitching, and flapping. Their dense, short feathers can also lock air between the skin and water to reduce friction and turbulence.

Penguins' superior swimming ability to start/brake, accelerate/decelerate, and turn swiftly is due to their freely waving wings. They allow penguins to propel and maneuver in the water and maintain balance on land.

Hydrodynamic performance of a penguin wing: Effect of feathering and flapping, Physics of Fluids (2023). DOI: 10.1063/5.0147776

Air conditioning in India and Europe poses risk for dramatic rise in emissions, says study

Between now and 2050 the use of air conditioners to cope with rising temperatures risks generating an increase in emissions in the order of 10 million metric tons of carbon dioxide in Europe and as much as 120 million metric tons in India.

These figures were revealed in a study published in the journal Scientific Reports by environmental economists Francesco Colelli and Enrica De Cian of Ca' Foscari University of Venice, CMCC (Euro-Mediterranean Center on Climate Change) and RFF-CMCC European Institute on Economics and the Environment and Ian Sue Wing of Boston University. The study is the first to illustrate the impacts of climate change on the demand for air conditioners and electricity for cooling in Europe and India: between now and 2050, with the current fuel mix, there is a risk of a mismatch between what is done for adaptation and mitigation, with increased emissions as a result. The rush to buy new air conditioners in the residential sector and the resulting increased use of electricity associated will characterize both relatively richer but more temperate European countries, and relatively poorer but warmer Indian states. The study estimates that by 2050, under a +2/-3 °C warming forecast, air-conditioning uptake could double in Europe and grow fourfold in India, reaching about 40% of homes in both regions. On the one hand, more air conditioning will bring benefits to the population by reducing the heat exposure connected to global warming. Researchers have estimated that cooling technologies will lead the population being exposed to 40% less heat in Europe and 35% less in India by 2050.

On the other hand, this will have a strong impact on emissions. Between now and 2050 the energy production required by the increased use of air conditioners will cause a rise in annual CO₂ emissions between 7 and 17 million tons in Europe, and between 38 and 160 million tons in India.

Francesco Pietro Colelli et al, Air-conditioning adoption and electricity demand highlight climate change mitigation–adaptation tradeoffs, Scientific Reports (2023). DOI: 10.1038/s41598-023-31469-z

"Predatory bacteria" provide hope for chlorine-free drinking water

 In a unique study carried out in drinking water pipes in Sweden, researchers  tested what would happen if chlorine was omitted from drinking water. The result? An increase in bacteria, of course, but after a while something surprising happened: a harmless predatory bacteria grew in numbers and ate most of the other bacteria. The study suggests that chlorine is not always needed if the filtration is efficient - and that predatory bacteria could perhaps be used to purify water in the future.

Just as human intestines contain a rich bacterial flora, many types of bacteria thrive in our drinking water and the pipes that transport them. On the inside of pipe walls is a thin, slippery coating, called a biofilm, which protects and supports bacteria. These bacteria have adapted to life in the presence of chlorine, which otherwise has the primary task to kill bacteria, particularity bacteria that can make humans sick.

An ordinary glass of drinking water contains a lot of harmless bacteria. Chlorine, however, which in the studied piping system was added in the form of monochloramine, is not wholly unproblematic.

Chlorine is an effective way to minimize growth of bacteria, but there is a risk of potential health impacts from byproducts that form with the chlorine. Chlorine has been linked to cancer and foetal damage and studying whether chlorine could be replaced by other methods is therefore relevant.

Our drinking water is currently purified in several stages. Depending on the type of water, companies use various kinds of filters, and UV light but the last stage is almost always the addition of chlorine.

In the present experiment, when the chlorine disappeared, certain types of bacteria starved while others grew and thrived. The biggest surprise for the researchers came in the third chlorine-free month when it was observed that certain bacteria had drastically decreased in number. And one special type of bacteria had increased: namely the predatory bacteria Bdellovibrio.

Researchers have not seen this exact type of bacteria in previous studies of this drinking water network. It has probably been lying concealed in the biofilm but was now given an opportunity. It’s totally harmless for us humans.

Each method of water treatmetn has its advantages and disadvantages. UV light is an effective method, but one disadvantage is that the lamps use a lot of energy. Biofilters often don’t require any energy at all but take up a considerable amount of space. Ultrafilters are expensive. Many drinking water treatment plants in Sweden purify water using a combination of methods. However, thsi study shows that harmful chlorine is not essential if you have other strategies to deal with, and monitor, bacteria.

Tage Rosenqvist et al, Succession of bacterial biofilm communities following removal of chloramine from a full-scale drinking water distribution system, npj Clean Water (2023). DOI: 10.1038/s41545-023-00253-x

Scientists Reveal That Jupiter Is Not What We're Being Told

Researchers discover that worms use electricity to jump

In nature, smaller animals often attach themselves to larger ones to "hitch a ride" and save energy migrating large distances. In paper published on June 21 in the journal Current Biology, researchers show how microscopic Caenorhabditis elegans worms can use electric fields to "jump" across Petri plates or onto insects, allowing them to glide through the air and attach themselves, for example, onto naturally charged bumblebee chauffeurs.

Pollinators, such as insects and hummingbirds, are known to be electrically charged, and it is thought that pollen is attracted by the electric field formed by the pollinator and the plant. However, it was not completely clear earlier whether electric fields are utilized for interactions between different terrestrial animals.

The researchers first began investigating this project when they noticed that the worms they cultivated often ended up on the lids of Petri dishes, opposite to the agar they were placed on. When the team attached a camera to observe this behavior, they found that it was not just because worms were climbing up the walls of the dish. Instead, they were leaping from the floor of the plate to the ceiling.

Suspecting travel by electric field, the researchers placed worms on a glass electrode and found that they only leaped to another electrode once charge was applied. Worms jumped at an average speed of .86 meters per second (close to a human's walking speed), which increased with electric field intensity.

Part 1

Next, the researchers rubbed flower pollen on a bumblebee so that it could exhibit a natural electric charge. Once close to these bees, worms stood on their tails, then jumped aboard. Some worms even piled on top of each other and jumped in a single column, transferring 80 worms at once across the gap.

"Worms stand on their tail to reduce the surface energy between their body and the substrate, thus making it easier for themselves to attach to other passing objects. In a column, one worm lifts multiple worms, and this worm takes off to transfer across the electric field while carrying all the column worms.

C. elegans is known to attach to bugs and snails for a ride, but because these animals don't carry electric fields well, they must make direct contact to do so. C. elegans is also known to jump on winged insects, but it was not clear how the worms were traversing such a significant distance for their microscopic size. This research makes the connection that winged insects naturally accumulate charge as they fly, producing an electric field that C. elegans can travel along.

---

It's unclear exactly how C. elegans performs this behavior. The worms' genetics might play a role. Researchers observed jumping in other worm species closely related to C. elegans, and they noted that mutants who are unable to sense electric fields jump less than their normal counterparts. However, more work is needed to determine exactly what genes are involved in making these jumps and whether other microorganisms can use electricity to jump as well.

Takuma Sugi, Caenorhabditis elegans transfers across a gap under an electric field as dispersal behavior, Current Biology (2023). DOI: 10.1016/j.cub.2023.05.042. www.cell.com/current-biology/f … 0960-9822(23)00674-7

Part 2

Scientists discover critical factors that determine the survival of airborne viruses

Critical insights into why airborne viruses lose their infectivity have been uncovered by scientists.

The findings, published in the Journal of the Royal Society Interface today, reveal how cleaner air kills the virus significantly quicker and why opening a window may be more important than originally thought. The research could shape future mitigation strategies for new viruses.

In the first study to measure differences in airborne stability of different variants of SARS-CoV-2 in inhalable particles, researchers show that the virus has become less capable of surviving in the air as it has evolved from the original strain through to the delta variant.

There are numerous factors that affect the transmission of airborne viruses, and these are often confounded with physical and environmental parameters that can affect viral longevity in the aerosol phase such as temperature, RH, air movement and UV light.

Through manipulating the gaseous content of the air, the researchers confirmed that the aerostability of the virus is controlled by the alkaline pH of the aerosol droplets containing the virus. Importantly, they describe how each of the SARS-CoV-2 variants has different stabilities while airborne, and that this stability is correlated with their sensitivities to alkaline pH conditions.

The high pH of exhaled SARS-CoV-2 virus droplets is likely a major driver of the loss of infectiousness, so the less acid in the air, the more alkaline the droplet, the faster the virus dies. Opening a window may be more important than originally thought as fresh air with lower carbon dioxide, reduces acid content in the atmosphere and means the virus dies significantly quicker.

Differences in Airborne Stability of SARS-CoV-2 Variants of Concern is Impacted by Alkalinity of Surrogates of Respiratory Aerosol, Journal of the Royal Society Interface (2023). DOI: 10.1098/rsif.2023.0062. royalsocietypublishing.org/doi … .1098/rsif.2023.0062

Disappearing Himalayan snow and ice will impact food production in ...

A major new assessment report from an eight-nation body, the International Center for Integrated Mountain Development (ICIMOD), to which WUR contributed, reveals the changes to the glaciers, snow and permafrost of the Hindu Kush Himalayan region driven by global warming are "unprecedented and largely irreversible."

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How climate change fuels extreme heat

Heatwaves across Asia and beyond have already broken records this year, while the arrival of the El Nino climate phenomenon will mean even more extreme temperatures.

The Cause of Morning Sickness

A team of researchers, after decades of research, has singled out one hormone which acts on the brain to cause vomiting as the likely cause of morning sickness – and added a stack of new evidence to back up their claims.

Researchers have had their sights set on a particular hormone called GDF15 ever since it was first detected at high levels in the blood serum of pregnant women in 2000. Since then, twin studies and genomic sequencing studies of people with severe nausea and vomiting in pregnancy have pointed to a genetic component of their illness involving two genes, including the one that encodes GDF15. The lines of evidence were aligning.

Nausea and vomiting are very common in the first trimester of pregnancy, but in around 2 percent of cases or 1 in 50 pregnancies, a most severe form develops known as hyperemesis gravidarum (HG).

Researchers uncovered a few new rare and common genetic variants in the GDF15 gene which they linked to the risk of HG. But the interplay between these genetic quirks, and the GDF15 hormone remained unclear.

latest batch of evidence supports the idea that GDF15 triggers hyperemesis.

Like many other proteins, GDF15 levels surge during pregnancy, and it seems some women are more sensitive to the hormone than others.

https://www.biorxiv.org/content/10.1101/2023.06.02.542661v1

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Physicists discover a new switch for superconductivity

Under certain conditions—usually exceedingly cold ones—some materials shift their structure to unlock new, superconducting behavior. This structural shift is known as a "nematic transition," and physicists suspect that it offers a new way to drive materials into a superconducting state where electrons can flow entirely friction-free.

But what exactly drives this transition in the first place? The answer could help scientists improve existing superconductors and discover new ones.

Now, physicists have identified the key to how one class of superconductors undergoes a nematic transition, and it's in surprising contrast to what many scientists had assumed.

The physicists made their discovery studying iron selenide (FeSe), a two-dimensional material that is the highest-temperature iron-based superconductor. The material is known to switch to a superconducting state at temperatures as high as 70 kelvins (close to -300 degrees Fahrenheit). Though still ultracold, this transition temperature is higher than that of most superconducting materials. The higher the temperature at which a material can exhibit superconductivity, the more promising it can be for use in the real world, such as for realizing powerful electromagnets for more precise and lightweight MRI machines or high-speed, magnetically levitating trains.

For those and other possibilities, scientists will first need to understand what drives a nematic switch in high-temperature superconductors like iron selenide. In other iron-based superconducting materials, scientists have observed that this switch occurs when individual atoms suddenly shift their magnetic spin toward one coordinated, preferred magnetic direction.

But the Physicists now found that iron selenide shifts through an entirely new mechanism. Rather than undergoing a coordinated shift in spins, atoms in iron selenide undergo a collective shift in their orbital energy. It's a fine distinction, but one that opens a new door to discovering unconventional superconductors.

Occhialini, C.A., et al, Spontaneous orbital polarization in the nematic phase of FeSe, Nature Materials (2023). DOI: 10.1038/s41563-023-01585-2. www.nature.com/articles/s41563-023-01585-2

The factual Face of Science

During my science communication journey, I found that the majority of people approach science in these four different ways:
Science is a subject students study in classrooms, so after the class they can leave it there and go home.
Science is something done by scientists in the lab, a thinking process that is creating a gap between the scientific world and the layman's world.
Science is a wonderful tool to authenticate their irrational beliefs, during which they can create their own new theories. Scientists call it 'junk science'.
Science is something that aids in developing the gadgets they use: cell phones, laptops, and television sets.

Now, how about expanding science from classrooms to the universal level? And present the full splendour of science to the world from several angles?
How about broadening the reach of scientific research from labs to laymen, erasing all the distances so that they can use it efficiently to its full extent?
How about making people throw junk science into trash cans by showing that science is a wonderful mechanism to accomplish several heroic things, and creating junk science is not one of them?
And how about showing people that science can develop a lot more than smart phones and laptops?

This is exactly what we do here.

Space travel can alter gene expression in white blood cells, weakening our immune system

Evidence is mounting that astronauts are more susceptible to infections while in space. For example, astronauts on board the International Space Station (ISS) commonly suffer from skin rashes, as well as respiratory and non-respiratory diseases. Astronauts are also known to shed more live virus particles; for example, the Epstein-Barr virus, varicella-zoster responsible for shingles, herpes-simplex-1 responsible for sores, and cytomegalovirus. These observations suggest that our immune system might be weakened by space travel. But what could cause such an immune deficit?

New research work shows that the expression of many genes related to immune functions rapidly decreases when astronauts reach space, while the opposite happens when they return to Earth after six months aboard the ISS.

The researchers studied gene expression in leukocytes (white blood cells) in a cohort of 14 astronauts, including three women and 11 men, who had resided on board the ISS for between 4.5 and 6.5 months between 2015 and 2019. Leukocytes were isolated from 4 milliliters blood drawn from each astronaut at 10 time points: once pre-flight, four times in flight, and five times back on Earth.

In total, 15,410 genes were found to be differentially expressed in leukocytes. Among these genes, the researchers identified two clusters, with 247 and 29 genes respectively, which changed their expression in tandem along the studied timeline.

Genes in the first cluster were dialed down when reaching space and back up when returning to Earth, while genes in the second followed the opposite pattern. Both clusters mostly consisted of genes that code for proteins, but with a difference: Their predominant function was related to immunity for the genes in the first cluster, and to cellular structures and functions for the second.

These results suggest that when someone travels to space, these changes in gene expression cause a rapid decrease in the strength of their immune system.

A weaker immunity increases the risk of infectious diseases, limiting astronauts' ability to perform their demanding missions in space. If an infection or an immune-related condition was to evolve to a severe state requiring medical care, astronauts while in space would have limited access to care, medication, or evacuation.

But there is a silver lining to this cloud: The data showed that most genes in either cluster returned to their pre-flight level of expression within one year after return on Earth, and typically much sooner—on average, after a few weeks. These results suggest that returning astronauts run an elevated risk of infection for at least one month after landing back on Earth.

The authors hypothesized that the change in gene expression of leukocytes under microgravity is triggered by "fluid shift," where blood plasma is redistributed from the lower to the upper part of the body, including the lymphatic system. This causes a reduction in plasma volume by between 10% and 15% within the first few days in space. Fluid shift is known to be accompanied by large-scale physiological adaptations, apparently including altered gene expression.

 The transcriptome response of astronaut leukocytes to long missions aboard the International Space Station reveals immune modulation, Frontiers in Immunology (2023). DOI: 10.3389/fimmu.2023.1171103. www.frontiersin.org/articles/1 … mu.2023.1171103/full

Even 'safe' air pollution levels can harm the developing brain, study finds

Air pollution is known to contribute to disease, which is why regulators such as the Environmental Protection Agency (EPA) set limits on emissions. But mounting evidence suggests that even pollution levels long thought to be safe can increase the risk of health problems, including in the brain.

Now new research  has shown that even levels of certain pollutants considered safe by the EPA are linked to changes in brain function over time. The study, just published in the journal Environment International, used brain scan data from more than 9,000 participants in the Adolescent Brain Cognitive Development (ABCD) study, the largest-ever nationwide study of youth brain health. Children exposed to more pollutants showed changes in connectivity between various brain regions. In some areas, they had more connections than normal; in other areas, they had fewer.

A deviation in any direction from a normal trajectory of brain development—whether brain networks are too connected or not connected enough—could be harmful down the line.

Communication between regions of the brain help us navigate virtually every moment of our day, from the way we take in information about our surroundings to how we think and feel. Many of those critical connections develop between the ages of 9 and 12 and can influence whether children experience normal or atypical cognitive and emotional development.

Air quality across the world, even though 'safe' by EPA standards, is contributing to changes in brain networks during this critical time, which may reflect an early biomarker for increased risk for cognitive and emotional problems later in life.

Devyn L. Cotter et al, Effects of ambient fine particulates, nitrogen dioxide, and ozone on maturation of functional brain networks across early adolescence, Environment International (2023). DOI: 10.1016/j.envint.2023.108001

Y chromosome affects cancer risk

The Y chromosome could be the reason that colorectal and bladder cancers are more aggressive ... and others who carry the chromosome. Researchers have found that the loss of the entire Y chromosome in some cells — which occurs naturally with age — raises the risk of aggressive bladder cancer and could allow bladder tumours to evade detection by the immune system. Separately, scientists identified a Y-chromosome gene in mice that bumps up the risk of some colorectal cancers spreading to other parts of the body by weakening connections between tumour cells. When the gene was deleted, tumour cells became less invasive, and were more likely to be recognized by immune cells. Together, the studies suggest that genetic factors — not just lifestyle — are responsible for the male bias that many cancers have.'

How the Y chromosome makes some cancers more deadly for men

Global diabetes cases expected to soar from 529 million to 1.3 billion by 2050

More than half a billion people are living with diabetes worldwide, affecting men, women, and children of all ages in every country, and that number is projected to more than double to 1.3 billion people in the next 30 years, with every country seeing an increase, as published recently in The Lancet.

The latest and most comprehensive calculations show the current global prevalence rate is 6.1%, making diabetes one of the top 10 leading causes of death and disability. At the super-region level, the highest rate is 9.3% in North Africa and the Middle East, and that number is projected to jump to 16.8% by 2050. The rate in Latin America and the Caribbean is projected to increase to 11.3%.

Diabetes was especially evident in people 65 and older in every country and recorded a prevalence rate of more than 20% for that demographic worldwide. The highest rate was 24.4% for those between ages 75 and 79. Examining the data by super-region, North Africa and the Middle East had the highest rate at 39.4% in this age group, while Central Europe, Eastern Europe, and Central Asia had the lowest rate at 19.8%.

Almost all global cases (96%) are type 2 diabetes (T2D); all 16 risk factors studied were associated with T2D. High body mass index (BMI) was the primary risk for T2D—accounting for 52.2% of T2D disability and mortality—followed by dietary risks, environmental/occupational risks, tobacco use, low physical activity, and alcohol use.

Global, regional, and national burden of diabetes from 1990 to 2021, with projections of prevalence to 2050: a systematic analysis for the Global Burden of Disease Study 2021, The Lancet (2023). DOI: 10.1016/S0140-6736(23)01301-6. www.thelancet.com/journals/lan … (23)01301-6/fulltext

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All the immunity, none of the symptoms, through dietary intervention

Worldwide, more than a million deaths occur each year due to diarrheal diseases that lead to dehydration and malnutrition. Yet, no vaccine exists to fight or prevent these diseases, which are caused by bacteria like certain strains of E. coli. Instead, people with bacterial infections must rely on the body taking one of two defense strategies: kill the intruders or impair the intruders but keep them around. If the body chooses to impair the bacteria, then the disease can occur without the diarrhea, but the infection can still be transmitted—a process called asymptomatic carriage.

Now,  scientists have found that pairing specific diets with disease-causing bacteria can create lasting immunity in mice without the costs of developing sickness, revealing a new potential vaccination strategy. Their findings, published in Science Advances on June 23, 2023, pave the way for the development of new vaccines that could promote immunity for those with diarrheal diseases and possibly other infections.

They  discovered that immunization against diarrheal infections is possible if they allow the bacteria to retain some of its disease-causing behaviour.

Researchers looked at how dietary interventions can create an asymptomatic infection, which they call a cooperative relationship between bacteria and host (the person or animal that the bacteria have infected) where the host does not experience any symptoms. They discovered that an iron-rich diet enabled mice to survive a normally lethal bacterial infection without ever developing signs of sickness or disease.

The high-iron diet increased unabsorbed sugar (glucose) in the mice's intestines, which the bacteria could feast on. The excess sugar served as a "bribe" for the bacteria, keeping them full and incentivized to not attack the host.

This process produced long-term asymptomatic infection with the bacteria, leading the researchers to think that the adaptive immune system (cells and proteins that "remember" infections) may be involved.

Grischa Chen et al, Cooperation between physiological defenses and immune resistance produces asymptomatic carriage of a lethal bacterial pathogen, Science Advances (2023). DOI: 10.1126/sciadv.adg8719. www.science.org/doi/10.1126/sciadv.adg8719

Understanding Earth gives us the means to better protect it.

Some Babies Are Born With 'Tails'

 In very rare cases, humans can be born with boneless rear-end appendages, sometimes up to 18 centimeters long. To date, official records have tallied about 40 babies born with 'true tails', consisting of soft, boneless, finger-like protrusions that are easily removed via surgery.

Nevertheless, the rare case studies tend to generate "an unusual amount of interest, excitement and anxiety", according to researchers. Often, this is because the 'tails' are conisidered to be benign, evolutionary remnants of a long lost ancestor.

As it turns out, that's based on an outdated theory that has been contentious for decades now. The reality for these children may be much darker, and they deserve medical attention, not our morbid fascination.

The appendages some babies are born with have historically been deemed 'true' or 'vestigial' tails. But that's a bit of a misnomer, as they aren't really like any other tail known in nature. They typically don't contain bones, cartilage, or a spinal cord. They just kind of hang there without a clear function.

Still, that doesn't mean these appendages are as harmless as scientists used to think.

The misunderstanding over the tail's origin starts with Charles Darwin himself. Over a century ago, Darwin proposed that human vestigial tails are evolutionary accidents, or rudimentary leftovers from a primate ancestor that was once tailed itself.

In the 1980s, scientists took this theory and ran with it. They argued that a genetic mutation, evolved by humans to erase our tails, could sometimes revert back to its ancestral state.

In 1985, a seminal paper defined two different types of 'tails' that human babies can be born with. The first, as mentioned before, is a vestigial or true tail, originally thought to be inherited from our ancestors.

But another type of outgrowth from the tailbone, which sometimes does include bone, is known as a 'pseudotail'.

Historically, the pseudotail has been the one associated with birth defects, and as such, it is not considered vestigial.

Part 1

As it turns out, both rare appendages probably represent an incomplete fusion of the spinal column, or what's known as a spinal dysraphism. This suggests their formation is not a harmless 'regression' in the evolutionary process but a concerning disturbance in an embryo's growth most likely resulting from a mix of genetic and environmental factors.

When a human embryo reaches about five weeks of development, it sprouts a tail-like structure composed of a neural tube and notochord, which is kind of like an early spinal cord.

By the eighth week of development, this tail is typically reabsorbed back into the embryo's body. If it sticks around until birth, it could indicate the presence of a larger birth defect.

In fact, human babies that are born with tails tend to have serious associated neurological defects. In 2008, for instance, a paper argued that "true vestigial tails are not benign" because they may be associated with underlying dysraphism.

Roughly half of the cases reviewed were associated with either meningocele or spina bifida occulta.

This suggests babies born with tails need greater medical attention than a simple surgery. And it strongly disagrees with the 1985 paper that argued "the true human tail is a benign condition not associated with any underlying [spinal] cord malformation."

Part 2

In fact, as far back as 1995, researchers were arguing that babies born with both 'true' and 'pseudo' tails should undergo neuroimaging as well as surgery to make sure their development was tracking like it should.

So why have vestigial tails been reported in case studies since as though they were innocent, undisputed consequences of our genetic heritage?

Part of the problem is that it is not yet known if a true tail is directly derived from the embryonic tail, as some scientists have suggested. There simply isn't enough research on where the congenital abnormality lies – partly because of how rare these case studies are.

Regardless of where a baby's tail came form, however, evidence strongly suggests it is the result of a congenital issue and is not a harmless vestigial trait.

For the life and health of these children, that's an important message that needs to be cleared up once and for all.

Part 3

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https://www.sciencealert.com/some-babies-are-born-with-tails-but-no...

A Hole in the World
There’s a hole under the Indian Ocean. Spanning more than three million square kilometers, the gouge is centered about 1,200 km southwest of the southern tip of India. Because of a low pull of gravity there, combined with higher gravity in surrounding areas, the sea level over the hole is 106 meters lower than the global average, according to a new study.

Why this is cool: Earth is not perfectly round. Rather, it is flatter at the poles and bulges around the equator, with other irregular peaks and valleys caused by different regions’ mass exerting different gravitational pulls. The hole under the Indian Ocean is the planet's most prominent gravitational anomaly.

What the experts say: Slabs of the floor of an ancient sea called the Tethys Ocean which existed 200 million years ago sank into the mantle, creating plumes of molten rock. The hole under the Indian Ocean probably took its present shape about 20 million years ago, when the plumes started to spread within the upper mantle, says Debanjan Pal, a doctoral student at the Indian Institute of Science in Bangalore, and lead author of the new study.

https://eos.org/science-updates/seismologists-search-for-the-indian...

https://www.scientificamerican.com/article/giant-gravity-hole-in-th...

Liver fibrosis linked to reduced cognitive ability and brain volume

Researchers have found that liver fibrosis — scarring of the liver tissue that occurs in many chronic liver diseases — is associated with reduce cognitive ability and, in certain regions of the brain, reduced brain volume. And this connection may be mediated in part by inflammation.

The researchers evaluated data on liver fibrosis, cognitive function — such as working memory, the ability to solve new problems, and processing speed — and gray matter volume in different regions of the brain. They found that, compared with healthy participants, those with liver fibrosis tended to have reduced cognitive ability and reduced gray matter volume in several brain regions, including the hippocampus, thalamus, striatum, and brain stem.

With this type of study, the researchers could not establish cause and effect; they could only evaluate correlations.

A growing body of scientific evidence is revealing that brain health and body health are interconnected, such that one often affects the other. 
More and more, people are starting to realize that there’s not this split between brain-based disorders and other types of physical health. We’re starting to understand that liver disease, heart disease, and other diseases will have impacts on the brain, and brain disorders have impacts on the body

https://www.sciencedirect.com/science/article/pii/S235239642300244X

What BMI doesn't tell you about your health

Clamor of gravitational waves from universe's merging supermassive black holes 'heard' for first time

Following 15 years of data collection in a galaxy-sized experiment, scientists have "heard" the perpetual chorus of gravitational waves rippling through our universe for the first time—and it's louder than expected.

The groundbreaking discovery was made by scientists with the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) who closely observed stars called pulsars that act as celestial metronomes. The newly detected gravitational waves—ripples in the fabric of space-time—are by far the most powerful ever measured: They carry roughly a million times as much energy as the one-off bursts of gravitational waves from black hole and neutron star mergers detected by experiments such as LIGO and Virgo.

Most of the gigantean gravitational waves are probably produced by pairs of supermassive black holes spiraling toward cataclysmic collisions throughout the cosmos, the NANOGrav scientists report in a series of new papers appearing today in The Astrophysical Journal Letters.

This is the first-ever evidence for the gravitational wave background. We've opened a new window of observation on the universe."

The existence and composition of the gravitational wave background—long theorized but never before heard—presents a treasure trove of new insights into long-standing questions, from the fate of supermassive black hole pairs to the frequency of galaxy mergers.

For now, NANOGrav can only measure the overall gravitational wave background rather than radiation from the individual "singers." 

The gravitational wave background is about twice as loud as what scientists expected. It's really at the upper end of what our models can create from just supermassive black holes.

The deafening volume may result from experimental limitations or heavier and more abundant supermassive black holes. But there's also the possibility that something else is generating powerful gravitational waves.

Part 1

The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/acdac6

Gabriella Agazie et al, The NANOGrav 15 yr Data Set: Observations and Timing of 68 Millisecond Pulsars, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/acda9a

Gabriella Agazie et al, The NANOGrav 15 yr Data Set: Detector Characterization and Noise Budget, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/acda88

Adeela Afzal et al, The NANOGrav 15 yr Data Set: Search for Signals from New Physics, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/acdc91

Astrophysical Interpretation of a Gravitational Wave Background from Massive Black Hold Binaries (accepted for publication in ApJL)

Bayesian Limits on GWs from Individual SMBHBs (accepted for publication in ApJL)

Part 2

A Star Fit For Life

Researchers observe rubber-like elasticity in liquid glycerol for the first time

Simple molecular liquids such as water or glycerol are of great importance for technical applications, in biology or even for understanding properties in the liquid state. Researchers  have now succeeded in observing liquid glycerol in a completely unexpected rubbery state.

In their article published in Proceedings of the National Academy of Sciences, the researchers report how they created rapidly expanding bubbles on the surface of the liquid in vacuum using a pulsed laser. However, the thin, micrometers-thick liquid envelope of the bubble did not behave like a viscous liquid dissipating deformation energy as expected, but like the elastic envelope of a rubber toy balloon, which can store and release elastic energy.

It is the first time an elasticity dominating the flow behavior in a Newtonian liquid like glycerol has been observed. Its existence is difficult to reconcile with common ideas about the interactions in liquid glycerol and motivates the search for more comprehensive descriptions. Surprisingly, the elasticity persists over such long timescales of several microseconds that it could be important for very rapid engineering applications such as micrometer-confined flows under high pressure. Yet, the question remains unsettled whether this behavior is a specific property of liquid glycerol, or rather a phenomenon that occurs in many molecular liquids under similar conditions but has not been observed so far.

 Meghanad Kayanattil et al, Rubber-like elasticity in laser-driven free surface flow of a Newtonian fluid, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2301956120

Science can help to end extreme poverty

Ending poverty starts with agreeing on how to measure what it means, argues a Nature editorial in the second of a series of articles on how science can help to support the teetering United Nations Sustainable Development Goals. The COVID-19 pandemic, Russia’s invasion of Ukraine, ongoing conflicts and the effects of climate change have all played a part in reversing a decades-long decline in poverty. More than 700 million people now live under the extreme-poverty line, defined as a daily income of less than US$2.15. Economic expansion and basic social and health-care protections could help to address the problem. More fundamentally, a rethink of how to measure poverty is needed. The global figure calculated using an index that includes housing, child mortality, clean water, sanitation and electricity is nearly double that calculated on the basis of income.

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Antacids in the ocean to try to gobble CO₂

The first commercial experiments are underway to see whether ocean alkalinity enhancement — essentially using antacids to help the ocean digest CO₂ — could slow global warming. The idea is to speed up a natural geochemical weathering process that ultimately transfers carbon dioxide from the atmosphere into the deep ocean. Quantifying the technology’s real-world impact remains the biggest challenge. The newly alkaline seawater needs to remain at the surface for carbon sequestration to occur. “If it gets drawn down into the ocean, then we might not get the benefit for another 1,000 years,” explains oceanographer Katja Fennel.