The secret life of puddles: Their value to nature is subtle, but hugely important

MARCH 29, 2021, by Gregory Moore, The Conversation

https://phys.org/news/2021-03-secret-life-puddles-nature-subtle.html

Credit: Shutterstock

It's official: Australians endured the coldest, wettest summer in at least five years thanks to La Niña, a climate phenomenon over the Pacific Ocean.

Before we knew it, autumn rolled in bringing more rain. Tragically, it led to widespread flooding across New South Wales, but elsewhere it helped to create more puddles. In our urban environments puddles are inconvenient: they can damage property and block our paths. But from a biological perspective, puddles are very important components of microhabitats and biodiversity.

We know for many animals—including birds and pets—puddles are a ready source of drinking water and provide a much-needed bath after a hot and dusty day. They're also well known for providing water-reliant species such as mosquitoes with opportunities for breeding, and many of us may remember watching tadpoles developing in puddles as children.

But puddles make more nuanced and subtle contributions to the natural world than you may have realised. So with more rain soon to arrive, let's explore why they're so valuable.

Take a closer look

Puddles are a diverse lot. They can be small or large, shallow or deep, long lasting or gone in a matter of hours. If you look closely at a puddle you will often find it is not even, especially on a slope.

The tiny ridges and depressions in puddles can make a big difference to wildlife. Credit: Shutterstock

Puddles consist of small, naturally formed ridges (berms) and depressions (swales). The berms form from silt and organic matter like leaf litter, which act as mini dams holding back the water in the swales behind them.

Berms and swales can be hard to see, but if you look closely they're everywhere and contribute to the retention of water, affecting the depth, spread and the very existence of the puddle.

All of this means they meet the needs of different species.

On rainy days you may have seen birds such as magpies feeding on worms that wriggle to the surface. Worm burrows can be two to three meters deep and many species might come to the surface to feed on leaf litter.

Worms emerge during and after heavy rain when water floods their burrows and soil becomes saturated. The worms won't drown but they do need oxygen, which is low in very wet soils.

Often in drier weather, getting a worm is not as easy as you might think—not even for the legendary early bird. So when heavy rain drives worms to the surface, it's party time for birds that feed on them, and they make the most of the opportunity.

A spotted pardalote inspecting puddle. 

Credit: Shutterstock

Swales in puddles often persist for days, which allows water-dependent insects to breed. Mosquito larvae, for instance, live in water for between four and 14 days, depending on temperature (so if you're worried about mozzies, then remember puddles have to persist for days before the pesky pests emerge).

Tadpoles take between four and 12 weeks to develop into frogs, and requires a deeper, long-lasting puddle. But these puddles are becoming rarer in urban areas, and so it's not often you see tadpoles or frogs in our suburbs.

Why seeds love them

Puddles also provide small, but important, reservoirs where seeds of many plant species germinate. In some cases, the seeds have chemical inhibitors in them, which prevent the seeds from germinating until after a period of heavy rainfall.

Then, the inhibitors are leeched from or diluted within the seeds, allowing them to germinate. Many desert species have this adaptation, including Australian eremophilas (emu bush).

In other cases, plants that grow all year round (annoyingly, weeds among them) need the dose of water puddles provide to kick start their very rapid growth and reproduction.

Easily germinated plants (such as tomatoes and cabbages) and ornamental flowering plants (such as hollyhocks and delphiniums) often require just a little extra water to trigger the whole germination process.

Puddles can wash away plant-inhibiting chemicals from the soil. Credit: Shutterstock

Important growing opportunities for iconic trees

Puddles also provide more subtle opportunities for wildlife. Take Australia's iconic river red gums (Eucalyptus camaldulensis) as an example. River red gums are water-loving trees that can withstand up to nine months of inundation without getting stressed.

What's not so well known, however, is river red gums produce chemicals that rain washes from their leaves, accumulating beneath the tree. These chemicals can inhibit the growth of plants, such as weeds, under the canopies.

This effect—where chemicals produced by one plant have an effect on other plants—is called "allelopathy." Many wattle species produce allelopathic chemicals and so do some important food plants, such as walnuts, rice and the common pea.

River red gum allelopathic chemicals can prevent the trees' own seedlings from growing near them. So river red gums require floods to wash the chemicals from the soil away. This mechanism allows river red gums to germinate and regenerate when the soil is wet, and in places away from the competition of mature trees.

Puddles can do the same thing, on a small scale, ensuring trees have plenty of opportunities to persist in the wild. This pattern of regeneration is important to provide a mosaic of species and trees of different ages, making up a diverse range of habitats for other wildlife.

Puddles are becoming harder to find in the suburbs. Credit: Shutterstock

Puddles are no piddling problem

As property developers iron the creases from our created landscapes with much less open space and more paved surfaces, puddles are becoming harder to find close to home.

Taking away puddles removes a whole range of microhabitats, jeopardizing the chances of a diverse range of species to breed and persist, especially in urban areas. These days, any loss of biodiversity is worrying.

So when you're next out and about after or during heavy rain, keep an eye out for puddles.

Remember the life that depends on them and, if you can, try not to disturb them. Perhaps capture the joy of jumping over—rather than in—them. They are not just a nuisance, but a key to a nuanced and biodiverse local community.

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High risk of acute kidney injury in patients undergoing treatment for infected total knee replacement

MARCH 29, 2021, by Wolters Kluwer Health

https://medicalxpress.com/news/2021-03-high-acute-kidney-injury-patients.html

Credit: CC0 Public Domain

Acute kidney injury (AKI) occurred in nearly 20 percent of patients who underwent surgery with implantation of antibiotic-loaded "spacers" and intravenous (IV) antibiotics for the treatment of deep infections after total knee arthroplasty, reports a study in The Journal of Bone & Joint Surgery.

Patients with preexisting chronic kidney disease (CKD) are at particularly high risk of AKI, according to the new research by Matthew P. Abdel, MD, and colleagues of the Mayo Clinic, Rochester, Minn.

High doses of antibiotics in bone cement linked to higher risk of AKI

Deep, periprosthetic joint infections are a devastating complication of failed total knee arthroplasty. The most common treatment is two-stage exchange arthroplasty, in which the knee implant is removed to enable treatment of the infection. This is often followed by placement of antibiotic-loaded bone cement (ALBC) spacers, which deliver high doses of antibiotics directly and continuously to the site of the infection. Once the infection has been eradicated, another operation is performed to place a new knee prosthesis.

However, there is a risk that high doses of antibiotics from the spacers, in addition to IV antibiotics, may result in a toxic effect on the kidneys. This toxicity could contribute to AKI: a serious complication marked by a sudden decline in kidney function. Orthopaedic surgeons have little evidence about the risk of AKI related to ALBC spacers and IV antibiotics, and even less evidence regarding the long-term outcomes of patients who develop AKI.

Dr. Abdel and colleagues analyzed the rates, risk factors, and outcomes of AKI in 424 patients who underwent two-stage exchange arthroplasty with ALBC spacers and IV antibiotics for chronically infected knee replacements. The patients were managed at the Mayo Clinic between 2000 and 2017. Before surgery, 15 percent of patients had preexisting CKD.

Overall, 19 percent of patients developed AKI while the ALBC spacers were in place and IV antibiotics were administered. Patients with preexisting CKD were significantly more likely to develop AKI compared with patients without preexisting CKD (45 percent versus 14 percent). After adjusting for other factors, patients with CKD were five times more likely to develop AKI (odds ratio 5.0).

The study identified several risk factors for AKI, including high doses of antibiotics used in the ALBC spacers (especially the commonly used antibiotics vancomycin and aminoglycoside). Certain factors linked to reduced blood flow to the kidneys, including high blood pressure, low blood volume, and atrial fibrillation (a heart rhythm disorder), also predicted an increased risk of AKI. Diabetes was another important risk factor.

Most patients who developed AKI regained kidney function. However, at an average of 6 years postoperatively, eight patients had developed CKD while four were on dialysis.

Acute kidney injury is a relatively common complication of many medical conditions and procedures, including orthopaedic surgery and heart surgery. The study provides new evidence on AKI in a large series of patients treated for infected total knee replacements at a single medical center.

The findings highlight the particularly high risk of AKI among patients with preexisting CKD. Dr. Abdel and colleagues emphasize the importance of screening to identify patients with possible decreases in kidney function before two-stage exchange arthroplasty.

The study also draws attention to the risk of AKI related to toxicity from ALBC spacers and IV antibiotics. Dr. Abdel and coauthors have taken steps to limit the doses of certain antibiotics used in spacers. However, they add, "While higher antibiotic doses in ALBC spacers can lead to AKIs, these doses are also a crucial factor for infection eradication."

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Researchers use AI datasets to track feral pigs, minimize disease risk

MARCH 29, 2021, by Brad Buck, University of Florida

https://phys.org/news/2021-03-ai-datasets-track-feral-pigs.html

Credit: CC0 Public Domain

Feral pigs cost the agriculture industry at least $1.5 billion in damage, disease and control costs around the United States annually, running rampant on large swaths of grazing lands. The swine root in soil and eat most everything in sight.

Farmers and ranchers will benefit from research by University of Florida scientists who are using artificial intelligence to gather data on feral hog reproduction and movement.

As they roam grazing land, feral swine carry pathogens that cause multiple diseases in cattle, like Brucella. Other pathogens, like foot-and-mouth disease, are not present in the United States, but wild pigs have the ability to transmit these foreign animal diseases.

"If a foreign animal disease became established in wild pigs in the United States, it would devastate the commercial swine and cattle industry. These foreign diseases are pathogens not found in the United States, but because of the severity of disease and high contagiousness, infected cattle or swine are culled. It would be nearly impossible to rid ourselves of a foreign animal disease if it became established in wild pigs," said Samantha Wisely, a UF/IFAS professor of wildlife ecology and conservation. "Wild pigs also cause millions of dollars a year to cattlemen in lost forage and degraded pastures."

Wisely will conduct her latest feral pig research at Archbold's Buck Island Ranch, in southeastern Highlands County. There, she'll collaborate with station researcher Raoul Boughton, who used AI to identify pigs from millions of pictures taken by remotely triggered wildlife cameras. Using these techniques, Wisely and others will further use this AI-generated dataset of pictures to track the movements of groups of pigs, called sounders, to predict how pathogens spread from pig to pig in Florida grazing lands.

"The camera array on Buck Island Ranch allows us to monitor many animals over a large area to truly understand population level responses to animal control, disease transmission and cattle management," she said.

With this project, Wisely plans to expand on research already done by Tyler Buckley, a master's student in wildlife ecology and conservation in the UF/IFAS College of Agricultural and Life Sciences. For his thesis, Buckley used the large array of wildlife cameras to estimate reproduction in wild pigs.

Buckley used an AI-generated dataset that identified images of the wild pigs at Buck Island Ranch to learn more about how quickly they can reproduce. Machine learning algorithms allowed a computer to sort through millions of photographs from dozens of cameras to identify the pictures that contained wild pigs, said Wisely, who is co-supervising Buckley's thesis with Boughton.

Buckley studied the number of piglets associated with a sow and compared that number before and after a large wild pig-removal event. Landowners use several methods to reduce the number of pigs on their property, including hunting and trapping.

Buckley found that sows increased the number of piglets they produce once the population size began to decrease due to culling.

"We need to understand how to manage pig populations without creating an influx of young piglets. When young pigs make up the majority of a population, diseases transmit among individuals more efficiently because those young pigs are more likely to become infected than older individuals," Wisely said. "If we track the population's response to different types of removal plans—perhaps we can find one that doesn't increase disease risk."

Buckley conducted his research while a graduate student at the UF/IFAS Range Cattle Research and Education Center in Ona, in Hardee County. He will defend his thesis this summer.

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Apes constantly reinvent the wheel

MARCH 29, 2021, by University of Tübingen

https://phys.org/news/2021-03-apes-constantly-reinvent-wheel.html

Credit: CC0 Public Domain

Great apes do not pass on their behavior to the next generation. Unlike humans, they do not copy the specific knowledge of those around them, instead learning it anew in each generation. This is shown in a study by Dr. Alba Motes-Rodrigo and Dr. Claudio Tennie of the "Tools and Culture in Early Hominins" research group at the University of Tübingen. "Metaphorically speaking, apes constantly have to reinvent the wheel. But the shape of the wheel does not change in the process," Tennie explains.

The Early Prehistory and Quaternary Ecology team searched all published reports on great apes for statements about locally unique behavioral patterns present in a single great ape population, such as the use of leaves as spoons to drink water by chimpanzees. These were then systematically examined for accuracy. By searching for locally unique behaviors, the researchers indirectly tested whether great ape cultures are built on the same transmission mechanisms as human cultures. The resulting study has been published in the journal Biological Reviews.

In human culture, behaviors are learned by people observing and copying each other's behavior. In this way, valuable know-how is passed on to the next generation. In the process, behaviors are often slightly modified, because people make mistakes when copying or add their own alterations. As a result, human culture changes from generation to generation. Alba Motes-Rodrigo compares this to the telephone game, in which each player whispers a term into the next player's ear. The term passes among players and, due to errors in hearing, is likewise frequently changed from the original word.

Exactly when humans began copying each other in this way is hotly debated. According to one theory, the ability to copy behavior goes back millions of years and is also present in modern apes. Another theory proposes that modern apes are incapable of copying each other's behavior, as were many human ancestors.

Alba Motes-Rodrigo and Claudio Tennie used a new approach to look for evidence of the process of know-how copying in great apes. They sought to identify behaviors in ape populations that have undergone changes from generation to generation. "If ape behavior is really based on copying, as it is in humans, we would expect behavioral details to have changed culturally, and therefore there should by now be individual behaviors that are restricted to only one population in one place," Motes-Rodrigo explains.

The team therefore searched for locally unique behavioral patterns in great apes, both in all published reports on the animals and in interviews with experts. They found that the overwhelming majority of great ape behaviors are not locally unique. Out of hundreds of ape behavior patterns, only three could not be found elsewhere.

According to the research team, these results show that ape culture is maintained by different learning mechanisms than those of human culture. Unlike humans, apes do not copy each other's know-how, but reinvent each of their behaviors over and over again in each population and in each generation. "In the process, they are merely stimulated to these reinventions by others, but without copying the particular form of behavior. This finding seems surprising, but it is supported by recent experimental studies in comparative cognitive science," Tennie says. In these studies, great apes copied new behaviors only if they had previously been trained by humans to do so. Therefore, more and more evidence suggest that modern humans and great apes acquire their behavior in different ways.

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Psychedelic drugs: how the brains of informed users are different

MARCH 24, 2021, by Barbara Sahakian and George Savulich, The Conversation

https://medicalxpress.com/news/2021-03-psychedelic-drugs-brains-users.html

Credit: Bruce Rolff/Shutterstock

There is a new generation of drug users out there who possess highly detailed pharmacological and technical knowledge about the drugs they take. "Psychonauts" (meaning "navigator of the soul") are enthusiastic and deliberate experimenters of hallucinogens, including psychedelic drugs, both synthetic and natural, for self-exploration, spiritual attainment or inducing an altered state of consciousness.

Also called "cyber-psychonauts" or "e-psychonauts," many refer to themselves as followers of shamanism. They take an almost scientific approach to documenting their experiences and sharing them online. Their motivations therefore differ from those of people who take drugs to socially connect with others at clubs, parties and music festivals.

We don't know a lot about psychonauts as they haven't been studied much. But in our latest research, published in Frontiers in Psychiatry, we have discovered how the behaviour and brains of psychonauts may be different from those of other people.

The few surveys and reviews that have been carried out so far indicate that psychonauts are typically single, well-educated, young adult men with good IT skills. They often report feeling more euphoric, empathetic, alert and creative when taking hallucinogenic drugs. This makes sense as we know hallucinogenic drugs work by stimulating serotonin receptors in the brain's prefrontal cortex, which can alter mood, sensory perception and cognition. Some also have stimulant effects.

Changing market

It's hard to keep up with the latest hallucinogenic drugs. "Novel psychoactive substances" are compounds that are newly designed or available to produce or mimic the same effects as other drugs, such as ecstasy, cannabis and amphetamines. Formerly called "legal highs", these substances first rose to prominence in the UK in 2009. They remained legal until the 2016 Psychoactive Substances Act placed a blanket ban on their production and trade.

However, the explosion of new substances, ambiguous compounds and rapidly changing names under which products continue to be sold have perpetuated a cat-and-mouse game between legislators and users.

With the closure of "head shops" that sell drugs and their paraphernalia around the UK, the internet has dramatically changed the way in which illegal and prescription drugs can be purchased on the underground market. Rogue websites sell novel psychoactive substances online without manufacturing or pharmaceutical regulation. Details of compounds and combinations are not fully disclosed, and many new drugs are given the paradoxical label: "not for human consumption".

But psychonauts keep records of their experiences and frequently engage in online forums to discuss new psychedelic trends. Online drug forum communities therefore offer a unique environment to interact with like-minded individuals in an open and anonymised manner. The aim is to share information about drug purity, dosage and safety prior to experimentation.

Psychonaut profile

Since so little is known about psychonauts, we were interested to learn more about their personality and cognition. To do this, we studied 82 people. These included psychonauts, "club drug" users who were seeking help for their use, and non-drug users. Indeed, we found differences in both personality and cognition between these three groups.

Cognitive processes can be divided into "hot" and "cold", relating to two partially segregated loops in the brain. The cold loop includes the dorsal lateral prefrontal cortex (involved in planning) and the hot loop includes the orbitofrontal cortex (involved in risky decision making), ventral striatum and amygdala (the latter two support emotion and behaviour).

Our results showed that psychonauts had no problems in "cold" cognition—what we usually use at work, such as attention, planning and problem solving. But they were different from non-users when it came to "hot" cognition – a type of emotional and social intelligence. For example, they took more risks than others and had high levels of sensation-seeking traits, suggesting they may be driven by the need for excitement and/or pursuing novel or unusual experiences.

This differed from "club drug" users who we identified from among people seeking help for addiction at a clinic. This group had "cold" cognitive problems in learning and memory. They also had difficulties controlling impulses. This is consistent with research on cocaine-dependent individuals, who tend to have problems with both "hot" and "cold" cognition. For example, cocaine-dependent users prefer immediate smaller rewards rather than waiting for larger delayed rewards. They like things now and do not want to wait, even if it means losing out on something bigger later.

The fact that psychonauts have no problems in "cold" cognition may help them be aware of the damaging effects of excessive drug dosage and prevent them from getting into harmful drug use. Since their main motivation is to enjoy and fully experience the effects of novel hallucinogenic drugs and to share this in detail with like-minded people, they try to be very careful of the amount of drugs they take. In future, we hope to conduct a longitudinal study and follow psychonauts and "club drug" users over time. This would allow us to determine whether the drugs themselves cause changes in cognition and whether sensation-seeking traits become stronger with more time spent sharing experiences with others online.

It is worth noting that psychonauts in our study were screened for psychiatric illnesses and were actively engaged in work or full-time education. This points towards a specific type of recreational drug user who incorporates regular drug taking into their lives. Psychonauts are positive about their lifestyle. This is in contrast to synthetic cannabinoid (for example "spice") users who we know develop impairments in functionality and wellbeing.

Hallucinogenic drugs, such as psilocybin, are being investigated as pharmacotherapy for treatment-resistant depression and other mental health conditions that are difficult to treat. In fact, the first UK clinic to offer ketamine-assisted psychotherapy for mental health disorders has recently opened.

Clinical trials for psychedelic drugs are currently ongoing, with the aim of obtaining broader regulatory body approval. More research is needed to better understand the psychedelic state, including its therapeutic potential. Continued engagement with psychonauts—both on and offline—may help provide the answers.

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“INSANE DEPTH OF COLD” TO BLAST BRITAIN [IN APRIL], AS SEA ICE AT BOTH POLES CONTINUES TO GROW EXPONENTIALLY

MARCH 29, 2021 ADMIN

https://electroverse.net/insane-depth-of-cold-to-blast-britain-as-sea-ice-at-both-poles-continues-to-grow/



For something purportedly “global,” AGW sure is illusive…


“INSANE DEPTH OF COLD” TO BLAST BRITAIN

An “insane depth of cold” is set to strike the UK over the Easter weekend, warns the Weather Outlook’s Brian Gaze.

Freezing temperatures and frosts will arrive in Scotland on Thursday, April 1, with “polar spring” conditions engulfing the majority of the country by Good Friday. Looking further ahead, the mercury is expected to sink even lower during the following week, as a violent kink in the jet stream (associated with the historically low solar activity we’re experiencing) delivers Arctic air to the lower-latitudes.

Thermometers could sink to -10C (14F) in northern parts, which would topple all-time daily cold records.

The UK’s lowest-ever recorded temperature for April 5, for example, is the -9C (15.8F) set in 1990, while 1935’s -8.9C (16F) for April 7 could also tumble. In fact, most of the daily benchmarks between early-to-mid April are under threat, including a few which have stood for more than a century.

What’s about the hit the UK (as well as western/northern Europe) looks unprecedented, and it’s arriving during a key time of the growing season, too — expect significant crop losses moving forward.

The freezing conditions aren’t fleeting either (unlike the two days of warmth on Mon and Tue); no, the Arctic looks set to park itself anomalously-far south for at least the first-half of April, with latest GFS runs revealing temps will only drop further as the month progresses.

April 13 (shown below) appears particularly cold, with -10C (14F) again possible in northern parts–a reading that would break the UK’s coldest-ever temperature for the date, which stands as the -9.2C (15.4F) set way back in 1890 (note: this particular forecast is a long way off, we’ll have to wait and see it materializes).

GFS 2m Temp Anomalies for April 13 [tropicaltidbits.com].

Record out–of-season snow is expected to accompany the cold, across Europe:

GFS Total Snowfall March 29 to April 14 [tropicaltidbits.com].

This is April, right?

SEA ICE AT BOTH POLES CONTINUES TO GROW EXPONENTIALLY

Antarctic sea ice fell to a “record minimum” in 2017 –after having reached a “record high” in 2015– but has been on something of a surge ever-since — a fact the AGW cabal is having an impossible time explaining.

Modern climate science states that “because the Earth’s polar regions are warming more quickly than the rest of the world, the temperature contrast that drives jet streams has decreased” which makes for a wavy jet stream flow. But in reality, satellite data reveals that sea ice extent around the southern pole has actually GROWN over the past 40+years, and also shows that temperatures across the continent have had no real trend.

According to the AGW cabal’s ‘Polar Amplification’ theory, Antarctica should be mirroring the trends seen in the Arctic: i.e., warming global temperatures should be melting sea ice exposing the darker sea beneath, absorbing the heat and increasing temperatures. But, as hinted at above, this simply isn’t happening; furthermore, polar outbreaks in the southern hemisphere (aka a weak and wavy jet stream flow) are also on the increase, just as they are in its northern counterpart.

Therefore, there must be an alternative explanation.

And our supposition is that it’s the Sun what’s doing it.

By the way, Arctic sea ice volume (or ‘thickness’) is also doing just fine this year:

Embedded below is the latest data from the National Snow and Ice Data Center (NSIDC).

It shows that sea ice at the South Pole has been on overdrive this season, climbing some 500,000 sq km above the mean. The chart also reveals this year’s growth is comfortably outstripping all four multidecadal averages: 1979 to 1990, 1991 to 2000, 2001 to 2010, and 2011 to 2020:

[NSIDC].

Four years ago, during late-March of 2017, Antarctic sea ice measured 3 million sq km, and now today, during late-March of 2021, measurements have reached 5+ million sq km –this fact is an impossibility under the global warming theory, yet here we are– and for those incapable of running the math for themselves, namely the useful idiots of the AGW Party, that’s an increase of 2 million sq km.

To finish, here’s the March 27, 2021 satellite photo of Antarctica.

The gains are clear to see, particularly around the SW.

[NSIDC]

For good measure, I’ve also included the latest satellite image of Arctic sea ice extent:

[NSIDC]

This, after 4+ decades of being told Arctic ice is on the verge of a catastrophic tipping point, is the state of play — that orange line of extent is close enough to the 1981-2010 median to be statistically irrelevant.

Furthermore, the gains witnessed across Antarctica easily offset the “missing” ice in and around the Arctic; but now, let’s not to fall into the trap of applying logic, that’s a censorable offense these days.

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The ancient fabric that no one knows how to make

By Zaria Gorvett, 16th March 2021

https://www.bbc.com/future/article/20210316-the-legendary-fabric-that-no-one-knows-how-to-make

(Image credit: Drik/ Bengal Muslin)

Nearly 200 years ago, Dhaka muslin was the most valuable fabric on the planet. Then it was lost altogether. How did this happen? And can we bring it back?

In late 18th-Century Europe, a new fashion led to an international scandal. In fact, an entire social class was accused of appearing in public naked.

The culprit was Dhaka muslin, a precious fabric imported from the city of the same name in what is now Bangladesh, then in Bengal. It was not like the muslin of today. Made via an elaborate, 16-step process with a rare cotton that only grew along the banks of the holy Meghna river, the cloth was considered one of the great treasures of the age. It had a truly global patronage, stretching back thousands of years – deemed worthy of clothing statues of goddesses in ancient Greece, countless emperors from distant lands, and generations of local Mughal royalty.

There were many different types, but the finest were honoured with evocative names conjured up by imperial poets, such as "baft-hawa", literally "woven air". These high-end muslins were said to be as light and soft as the wind. According to one traveller, they were so fluid you could pull a bolt – a length of 300ft, or 91m – through the centre of a ring. Another wrote that you could fit a piece of 60ft, or 18m, into a pocket snuff box.

Dhaka muslin was also more than a little transparent.

While traditionally, these premium fabrics were used to make saris and jamas – tunic-like garments worn by men – in the UK they transformed the style of the aristocracy, extinguishing the highly structured dresses of the Georgian era. Five-foot horizontal waistlines that could barely fit through doorways were out, and delicate, straight-up-and-down "chemise gowns" were in. Not only were these endowed with a racy gauzy quality, they were in the style of what was previously considered underwear.

In one popular satirical print by Isaac Cruikshank, a clique of women appear together in long, brightly coloured muslin dresses, through which you can clearly see their bottoms, nipples and pubic hair. Underneath reads the description, "Parisian Ladies in their Winter Dress for 1800".

Meanwhile in an equally misogynistic comedic excerpt from an English women's monthly magazine, a tailor helps a female client to achieve the latest fashion. "Madame, ’tis done in a moment," he assures her, then instructs her to remove her petticoat, then her pockets, then her corset and finally her sleeves… "‘Tis an easy matter, you see," he explains. "To be dressed in the fashion, you have only to undress."

Still, Dhaka muslin was a hit – with those who could afford it. It was the most expensive fabric of the era, with a retinue of dedicated fans that included the French queen Marie Antoinette, the French empress Joséphine Bonaparte and Jane Austen. But as quickly as this wonder-cloth struck Enlightenment Europe, it vanished.

19th century satirical printmakers enjoyed highlighting the perils of muslin dresses, such as the risk of appearing nude in strong sunlight, wind or rain 

(Credit: Alamy)

By the early 20th Century, Dhaka muslin had disappeared from every corner of the globe, with the only surviving examples stashed safely in valuable private collections and museums. The convoluted technique for making it was forgotten, and the only type of cotton that could be used, Gossypium arboreum var. neglecta – locally known as Phuti karpas – abruptly went extinct. How did this happen? And could it be reversed?

A fickle fibre

Dhaka muslin began with plants grown along the banks of the Meghna river, one of three which form the immense Ganges Delta – the largest in the world. Every spring, their maple-like leaves pushed up through the grey, silty soil, and made their journey towards straggly adulthood. Once fully grown, they produced a single daffodil-yellow flower twice a year, which gave way to a snowy floret of cotton fibres.

These were no ordinary fibres. Unlike the long, slender strands produced by its Central American cousin Gossypium hirsutum, which makes up 90% of the world’s cotton today, Phuti karpas produced threads that are stumpy and easily frayed. This might sound like a flaw, but it depends what you’re planning to do with them.

Indeed, the short fibres of the vanished shrub were useless for making cheap cotton cloth using industrial machinery. They were fickle to work with, and they’d snap easily if you tried to twist them into yarn this way. Instead, the local people tamed the rogue threads with a series of ingenious techniques developed over millennia.

The full process involved 16 steps, each of which was so specialist, it was carried out by a different village around Dhaka, which was then part of Bengal – some in what is now Bangladesh, some in what is now the Indian state of West Bengal. It was a true community effort, involving the young and old, men and women.

First, the balls of cotton were cleaned with the tiny, spine-like teeth on the jawbone of the boal catfish, a cannibalistic native of lakes and rivers in the region. Next came the spinning. The short cotton fibres required high levels of humidity to stretch them, so this stage was performed on boats, by skilled groups of young women in the early morning and late afternoon – the most humid times of day. Older people generally couldn’t spin the yarn, because they simply couldn’t see the threads.

Dhaka muslin was a favourite of Joséphine Bonaparte, the first wife of Napoleon, who owned several dresses inspired by the classical era

 (Credit: Alamy)

"You'd get tiny, tiny little joins between the cotton fibres, where they were linked together," says Sonia Ashmore, a design historian who authored a book about muslin in 2012. "It lent the surface a kind of roughness, which gives a very nice feel."

Finally, there was the weaving. This part could take months to complete, as classic jamdani designs – mostly geometric shapes depicting flowers – were integrated directly into the cloth, using the same technique that was used to create the famous royal tapestries from medieval Europe. The result was a minutely detailed artwork rendered in thousands of silvery, silky strands.

An Asian wonder

The region’s Western customers found it hard to believe that Dhaka muslin could possibly have been made by human hands – there were rumours that it was woven by mermaids, fairies and even ghosts. Some said that it was done underwater. "The lightness of it, the softness of it – it was like nothing we have today," says Ruby Ghaznavi, vice president of the Bangladesh National Craft Council.

The same weaving process continues in the region to this day, using lower-quality muslin from ordinary cotton threads instead of Phuti karpas. In 2013, the traditional art of jamdani weaving was protected by Unesco as a form of intangible cultural heritage.

But the real feat was the thread counts that could be achieved.

It was all going so well – then the British turned up

Higher thread counts are seen as desirable because they make materials softer, and tend to wear better over time – the more strands there are to begin with, the more there will remain to hold the fabric together when some begin to fray.

Saiful Islam, who runs a photo agency and leads a project to resurrect the fabric, says most versions made today have thread counts between 40 and 80 – meaning they contain roughly that number of criss-crossing horizontal and vertical threads per square inch of fabric. Dhaka muslin, on the other hand, had thread counts in the range of 800-1200 – an order of magnitude above any other cotton fabric that exists today.

Though Dhaka muslin vanished more than a century ago, there are still intact saris, tunics, scarves and dresses in museums today. Occasionally one will resurface at a high-end auction house such as Christie’s and Bonhams, and sell for thousands of pounds.

A colonial shambles

"The trade was built up and destroyed by the British East India Company," says Ashmore.

Long before Dhaka muslin was draped over aristocratic women in Europe, it was sold across the globe. It was popular with the Ancient Greeks and Romans, and muslin from "India" is mentioned in the book The Periplus of the Erythraean Sea, authored by an anonymous Egyptian merchant around 2,000 years ago.

This long post continues at:  https://www.bbc.com/future/article/20210316-the-legendary-fabric-that-no-one-knows-how-to-make

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Study: Extreme exercise can lead to mitochondrial functional impairment

MARCH 24, 2021 REPORT, by Bob Yirka , Medical Xpress

https://medicalxpress.com/news/2021-03-extreme-mitochondrial-functional-impairment.html

Credit: Unsplash/CC0 Public Domain

A team of researchers from the Swedish School of Sport and Health Sciences and the Karolinska Institutet, has found that people who go to extremes when exercising can go too far, resulting in mitochondrial functional impairment and insulin resistance. In their paper published in the journal Cell Metabolism, the group describes exercise experiments they conducted with volunteers and what they learned from them.

One of the things most people hear from their doctors is a suggestion to get more exercise. But in this new effort, the researchers have found that there is a limit to what the body can endure—too much training, they found, can lead to insulin resistance and mitochondrial functional impairment.

To learn more about the way the body responds to exercise, the researchers developed an extreme regimen to test the boundaries of seriously pushing the body to its limits. They then enlisted the assistance of 11 healthy young volunteers who were already keeping themselves in shape using some form of exercise.

The experiment had three phases. Volunteers rode exercise bikes for certain amounts of time over a four-week period. In the first phase, all the volunteers engaged in high-intensity pedaling for four- to eight-minute intervals over 36 minutes. In the second phase, duration of the workout was bumped up to 90 minutes. And in the third phase, it was bumped to 152 minutes over a week. During the experiments, the researchers collected muscle biopsies from each of the volunteers to measure mitochondrial function. Each volunteer also underwent glucose measurements to monitor insulin resistance.

The researchers found, as expected, that insulin remained at normal levels for phases one and two of the experiment. They also found that mitochondrial function improved over the first two phases, which was also expected—prior research has shown that normal exercise is good for mitochondrial function. But for phase three, they found that most of the volunteers experienced insulin resistance similar to a person developing diabetes. They also found that mitochondrial respiration fell by an average of 40% for the volunteers compared with samples collected during phase one of the experiment.

The researchers also found that oxygen consumption improved overall for the volunteers during the experiment, as did power output levels. But in an interesting twist, mitochondrial respiration did not fully recover after a week of normal exercise.

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The forgotten medieval fruit with a vulgar name

By Zaria Gorvett, 25th March 2021

https://www.bbc.com/future/article/20210325-the-strange-medieval-fruit-the-world-forgot

(Image credit: Alamy)

Medieval Europeans were fanatical about a strange fruit that could only be eaten rotten. Then it was forgotten altogether. Why did they love it so much? And why did it disappear?

In 2011, archaeologists found something unusual in a Roman toilet.

The team were excavating the ancient village of Tasgetium (now Eschenz, Switzerland), ruled by a Celtic king who was personally given the land by Julius Caesar. It was built on the banks of the river Rhine, along what was then an important trade route – and as a result, its remains have been steeped in water ever since. What should have rotted away centuries ago was uncovered in a remarkable state of preservation, protected by the lack of oxygen in the boggy conditions.

It was here that, nestled among the remains of familiar foods such as plums, damsons, cherries, peaches and walnuts in an ancient cesspit, the archaeologists found 19 curiously large seeds. Though they were, let's say, "deposited" there nearly 2,000 years ago, they almost looked fresh enough to have been found yesterday – except that the fruit they belong to is now so obscure, it can baffle even professional botanists.

The polite, socially acceptable name by which it's currently known is the medlar. But for the best part of 900 years, the fruit was called the "open-arse" – thought to be a reference to the appearance of its own large "calyx" or bottom. The medlar's aliases abroad were hardly more flattering. In France, it was variously known as "la partie postérieure de ce quadrupede" (the posterior part of this quadruped), "cu d'singe" (monkey's bottom), "cu d'ane" (donkey's bottom), and cul de chien (dog's bottom)… you get the idea.

And yet, medieval Europe was crazy about this fruit.

The fruit made regular appearences in artworks, such as this tapestry from around 1500 (Credit: Alamy)

The first record of the medlar's existence is a fragment of Greek poetry from the 7th Century BC. Eventually the fruit is thought to have fallen into the hands of the Romans, who brought it to southern France and Britain. In 800AD, Charlemagne included it on a list of plants that were mandatory in the king's many gardens, and nearly 200 years later, the English abbot and writer Ælfric of Eynsham first committed its rather rude sobriquet to the public record.

From there, the fruit's popularity steadily increased. It became a staple of medieval monasteries and royal courtyards, as well as public spaces such as village greens.

It's featured in Chaucer's Canterbury Tales, Shakespeare's Romeo and Juliet, and the two-time queen consort Anne of Brittany's Book of Hours – a kind of illustrated religious manuscript popular in the Middle Ages. Henry VIII had the medlar planted at Hampton Court, and gifted his French counterpart with large quantities.

The fruit reached its peak in the 1600s when it was widely grown across England – as ordinary as apples, pears, mulberries and quince. From this lofty pinnacle, it underwent a steady decline. It was still widely known until the early 20th Century, though less celebrated. Then in the 1950s it abruptly vanished from the public consciousness altogether.

Once a household name, described by one Roman commentator as amounting "almost to a craze", now the medlar is primarily grown as a romantic relic from the past – a niche plant for eccentric gardeners and a historical curiosity at palaces and museums.

Just a few decades after it disappeared, it was already mysterious to many greengrocers. In 1989, one American academic wrote that "probably not one in a hundred" botanists had seen a medlar. Today it's not sold at a single British supermarket. Where there are still plants growing in public spaces, they often go unrecognised and are left to rot on the ground.

What was it about this strange fruit that gripped medieval Europe, and why did it disappear?

Medlar trees are unfussy and long-lived, with even the most venerable specimens producing hundreds of fruit each year (Credit: Alamy)

It's not known for sure where the medlar originated, but some believe that it was domesticated around 3,000 years ago in Western Asia, by the Caspian Sea – where there are many different types to this day.

"Medlar" and "open-arse" can be used to refer to both the fruit and the shrub-like tree on which it's grown, Mespilus germanica – a close relative of roses, crab apples, and quinces. With a tangle of twisted, contorting branches at the base and a satisfying rounded canopy of elongated leaves, it was not only renowned for its fruit, but its aesthetic. Each spring, this is studded with single, star-shaped flowers which appear at such regular intervals that they could almost be painted on. By the autumn, the tree is a kaleidoscope of colours – green, yellow, brown and blood red.

The fruit are unusual for two reasons. Firstly, they're harvested in December – making them one of very few sources of sugar that would have been available in medieval winters. Secondly, they only become edible when they're rotten.

When they're first picked, medlars are greenish brown and resemble oddly-shaped onions or alien-looking persimmons. If they're eaten straight away, they can make you violently ill – one 18th Century doctor and botanist said that they cause diarrhoea. But if you put them in a crate of sawdust or straw and forget about them for several weeks, they gradually darken and their hard, astringent flesh softens to the consistency of a baked apple.

The exact chemical mechanism involved remains elusive, but broadly, enzymes in the fruit break down complex carbohydrates into simple sugars such as fructose and glucose, and it becomes richer in malic acid – the main culprit behind the sour taste of other fruits such as apples. Meanwhile, harsh tannins, which contribute to the bitter astringency of younger red wines, and antioxidants such as ascorbic acid (Vitamin C), are depleted.

Medlar jam was a popular Christmas gift in the late 19th century

 (Credit: Alamy)

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https://www.bbc.com/future/article/20210325-the-strange-medieval-fruit-the-world-forgot

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E. Coli calculus: Bacteria find the derivative optimally

MARCH 24, 2021, by University of Tokyo

https://phys.org/news/2021-03-coli-calculus-bacteria-derivative-optimally.html

The University of Tokyo researchers use information theory to show that the accepted biochemical model of bacterial chemical sensing is mathematically equivalent to the optimal solution, with implications for microbiology and robotics 

Credit: Institute of Industrial Science, the University of Tokyo

Scientists from the Graduate School of Information Science and Technology at The University of Tokyo calculated the efficiency of the sensory network that bacteria use to move towards food and found it to be optimal from an information theory standpoint. This work may lead to a better understanding of bacterial behavior and their sensory networks.

Despite being single-celled organisms, bacteria such as E. Coli can perform some impressive feats of sensing and adaptation in constantly changing environmental conditions. For example, these bacteria can sense the presence of a chemical gradient indicating the direction of food and move towards it. This process is called chemotaxis, and has been shown to be remarkably efficient, both for its high sensitivity to tiny changes in concentration and for its ability to adapt to background levels. However, the question of whether this is the best possible sensing system that can exist in noisy environments, or a suboptimal evolutionary compromise, has not been determined.

Now, researchers from The University of Tokyo have shown that the standard model biologists use to describe bacterial chemotaxis is, in fact, mathematically equivalent to the optimal dynamics. In this framework, receptors on the surface of the bacterium can be modulated by the presence of the target molecules, but this signaling network can be affected by random noise. Once the bacteria determine if they are swimming towards or away from the food, they can adjust their swimming behavior accordingly.

"E. coli can either move in a straight line or randomly reorient via tumbling. By reducing the frequency of tumbling when it senses a positive attractant concentration gradient, the bacterium can preferentially move toward the food," first author Kento Nakamura says.

Using nonlinear filtering theory, which is a branch of information theory that deals with updating information based on a stream of real-time information, the scientists showed that the system used by bacteria is indeed optimal.

"We find that the best possible noise-filtering system coincides with the biochemical model of the E. coli sensory system," explains senior author Tetsuya J. Kobayashi.

The findings of this research may also be applied to sensory systems in other organisms, such as G protein-coupled receptors used for vision. Since all living systems need to be able to sense and react to their environments, this project can help evaluate the efficiency of information filtering more generally.

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Light show over US sky likely SpaceX debris re-entering atmosphere

MARCH 26, 2021

https://phys.org/news/2021-03-sky-spacex-debris-re-entering-atmosphere.html

Credit: Pixabay/CC0 Public Domain

A spectacular display of lights that streamed across the night sky over the US Pacific Northwest was probably debris from a SpaceX mission re-entering the atmosphere, the National Weather Service (NWS) said.

"While we await further confirmation on the details, here's the unofficial information we have so far. The widely reported bright objects in the sky were the debris from a Falcon 9 rocket 2nd stage," NWS Seattle tweeted.

Videos posted on social media showed a thick cluster of glowing dots with blazing trails of light moving slowly across the sky before fizzling out, with users speculating the phenomenon might be a meteor shower or even, jokingly, an alien invasion.

Local media reported multiple sightings just after 9 pm local time, with videos posted online from Washington state and Oregon.

NWS Seattle said the sight was more likely to be caused by space debris rather than a meteor or similar object because the latter would be moving far faster, a conclusion backed up by several meteorologists quoted by local media.

Jonathan McDowell from Harvard's Center for Astrophysics also pointed to the Falcon 9 rocket stage as the source of the firework-like display.

"The Falcon 9 second stage from the Mar 4 Starlink launch failed to make a deorbit burn and is now re-entering after 22 days in orbit," he tweeted, referring to a rocket launched on March 4 to carry 60 Starlink internet relay satellites into orbit.

A deorbit burn is a firing of a spacecraft's thrusters to slow the vehicle and begin its descent, according to NASA's website.

McDowell tweeted that while "we could predict this rocket stage would re-enter today", the speed at which it was travelling meant it was difficult to predict where it would be seen.

There were no immediate reports of damage, with NWS Seattle saying there were no expected impacts on the ground.

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Guatemala's Pacaya volcano continues erupting after 50 days

MARCH 26, 2021

https://phys.org/news/2021-03-guatemala-pacaya-volcano-erupting-days.html

Lava flowing out of the Pacaya volcano, 25km south of Guatemala City on March 25, 2021

The Pacaya volcano close to Guatemala's capital is maintaining "high levels" of activity with strong eruptions, ash clouds and rivers of lava spewing out, officials said on Friday.


The 2,500-meter (8,200-foot) volcano that lies 25 kilometers to the south of Guatemala City has been erupting for 50 days, damaging plantations in the path of the lava.

Pacaya is expelling ash up to 500 meters from its crater, located 2.5 kilometers southwest of the cone, the vulcanology institute said in a statement.

Falling ash was registered in the El Rodeo and El Patrocinio communities, the institute said, adding that "the volcanic activity is considered at high levels."

The activity has produced a lava flow 2.2 kilometers long on the west flank of the volcano.

The national disaster coordination body said the lava had caused "fire and the destruction of coffee and avocado plantations."

Despite the spectacular eruptions, inhabitants of the surrounding villages have chosen to stay at home.

The civil protection body has asked authorities to prohibit people from approaching either the crater or the lava flows due to the risk of falling debris.

On Tuesday, a change in wind direction forced the closure of the country's only international airport for almost 24 hours due to ash.

Falling ash from the Pacaya volcano forced the closure of Guatemala's only international airport for almost 24 hours

Authorities have advised people to keep clear of the Pacaya volcano's crater and lava flows

A powerful eruption of the Pacaya volcano in May 2010 killed a television journalist covering the event.

Guatemala has 30 volcanos including two other active ones.

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Planting false memories in people's minds and then erasing them

MARCH 23, 2021 REPORT, by Bob Yirka , Medical Xpress

https://medicalxpress.com/news/2021-03-false-memories-people-minds-erasing.html

Credit: Unsplash/CC0 Public Domain

A small team of researchers from the University of Hagen, Leibniz-Institut für Wissensmedien, Johannes Gutenberg Universität Mainz and the University of Portsmouth has found that false memories planted in the minds of volunteers can be just as easily erased. In their paper published in Proceedings of the National Academy of Sciences, the group describes memory experiments they conducted with volunteers and what they learned from them.

False memories, as their name implies, are those of places or events that have never happened. Prior research has shown that false memories can arise naturally due to cues that the mind uses to create memories of events that might have happened but did not. Prior research has also shown that it is possible to plant false memories in other people using certain psychological tricks. Notably, such tricks have been used in well-known criminal trials to push possible witnesses into remembering things that did not occur.

Typically, these tricks involve suggesting to a person that an event occurred and then using an external trusted source to back up the claim. In this new effort, the researchers attempted to plant false memories in 52 volunteers by creating plausible stories from their childhoods and mixing them with events that actually happened. The researchers then backed up the false memories by asking the parents of the volunteers to claim that they happened, as well. Over the course of several sessions, many of the volunteers came to believe the accounts were true and some of them generated false memories of them.

Next, the researchers set about erasing the false memories from the minds of those volunteers. They found they were able to do so by first asking them to identify the source of the memory and then by explaining to them that sometimes, false memories can be created when people are asked to recall them multiple times. Over several sessions, the researchers found that the volunteers began to lose the memories they had created of the false event. The researchers also invited the volunteers back again a year later and found that 74% of those who had created false memories had lost their memories of the false event or had simply rejected them as having ever happened.

This para I am adding from another source.  CC

The implications of this kind of disturbing but important research might be far-reaching in the realm of criminal justice, with methods employed by prosecutors, police, and others called into question when seeking the ‘truth’ of a past event.

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