https://www.eurekalert.org/news-releases/1138157

EXCERPTS: What enables us to sustain effort toward goals, even when the task becomes increasingly difficult? A recent study by researchers at Nagoya University in Japan revealed the underlying brain mechanism, showing that orexin neurons play a crucial role in driving and regulating motivated behavior. The findings were published in Proceedings of the National Academy of Sciences of the United States of America (PNAS).

Motivational deficits, including loss of motivation, are often seen in mental disorders such as depression, addiction and ADHD. However, the brain mechanisms behind these problems remain largely unclear.

The research team, led by Hiroyuki Mizoguchi, associate professor, and Kiyofumi Yamada, professor emeritus, at Nagoya University's Graduate School of Medicine, focused on orexin neurons. These neurons regulate essential physiological functions such as sleep, appetite and energy expenditure. Although recent studies suggest that orexin neurons also influence motivation, their exact role has remained unclear.

[...] suppressing orexin neurons impaired motivation, but artificially exciting them beyond natural levels did not enhance it. The researchers say this asymmetry suggests orexin neurons are necessary for sustaining motivated behavior, though simply raising their activity may not be sufficient to increase it. Further studies are needed to determine what governs this effect, such as the duration or pattern of orexin neuron activity.

Mizoguchi concluded, "Our study demonstrated significant changes in orexin neuron activity depending on expected rewards and the effort required, suggesting a potential mechanism for translating expectations into sustained action."

Future research will investigate the input and output circuits connected to orexin neurons. A deeper understanding of orexin function may inform new approaches to addressing motivational deficits, including loss of motivation or challenges in sustaining goal-directed behavior. (MORE - missing details, no ads)

Early snakes explored life underground, on land and at sea
https://www.scivillage.com/thread-21019.html

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Life speaks one universal language to activate genes. It speaks many more to silence them
https://www.eurekalert.org/news-releases/1137882

INTRO: The signals that cells use to switch genes on have remained almost unchanged across two billion years of evolution, but the ones used to switch genes off vary dramatically from one branch of life to another, according to a new study from the Centre for Genomic Regulation (CRG) in Barcelona.

The findings, published today in Nature Genetics, are thanks to the broadest comparative exercise to date of how different life forms regulate their genomes. The study carried out the first detailed analysis of chromatin, the protein scaffold that controls how DNA is read, in several major branches of life that have been largely absent from studies to date, including lineages such as discobans, rhizarians, ichtyosporeans and cryptomonads.

"The cell's instructions for activating genes are essentially the same in a human, a sea anemone and a soil amoeba," says Dr Arnau Sebé-Pedrós, ICREA Research Professor and senior author of the study.

"But the instructions for silencing genes and other genomic elements like transposons have been continuously evolving since our last common eukaryotic ancestor. Different branches of life have developed different molecular toolkits to do the same thing,” he adds.

The work helps understand how genomes evolved on Earth and could have implications for medical research into diseases involving faulty gene regulation. It also delivers a new method, developed at the CRG, which can help support international efforts to characterise life on Earth at the molecular level.

DNA is wrapped, inside every cell, around proteins called histones. Small chemical tags attached to these proteins tell the cell which stretches of DNA to read and which to ignore. The system, known as chromatin regulation, is what allows the same genome to produce a liver cell or a neuron, and a leaf or a root. Faults in the regulation of chromatin underpin many human diseases, including cancers.

The chemical tags are ancient, dating back roughly two billion years to a single-celled organism known as the Last Eukaryotic Common Ancestor, or LECA, the founder of all complex cellular life, from which every plant, animal, fungus and protist on Earth descends.

The enzymes that add and remove the tags are also broadly shared across plants, animals, fungi and microbial eukaryotes. Until now, however, almost all detailed knowledge of how these tags work has come from a handful of laboratory species such as humans, mice, fruit flies, yeast and the model plant Arabidopsis. The vast majority of life's diversity has remained unexplored at this level... (MORE - no ads)

https://www.eurekalert.org/news-releases/1138474

INTRO: Snakes are highly modified lizards, with more than 4,000 living species today. The origin of snakes has long been one of evolutionary biology's most debated questions. Their sparse fossil record has made it hard to pin down what drove the evolution of their limbless body plan.

For decades, scientists have argued whether the elongated, limbless snake body first evolved as an adaptation to burrowing or to life in water. A study published in Nature challenges that framing: early snakes did not follow one ecological path but experimented with multiple habitats and sensory strategies.

“Our findings show that early snakes had already achieved remarkable ecological and morphological diversity by the Late Cretaceous, around 80 million years ago,” says lead author Tiago Simões, Assistant Professor at Princeton University... (MORE - no ads)

https://www.eurekalert.org/news-releases/1138147

INTRO: Along the three coasts of the contiguous United States, a silent race unfolds. Fueled by climate change, sea levels rise faster than at any time in recent geologic history. Meanwhile, coastal wetlands cling to a slim lead, lifted on newly accumulated sediments or moving inland as encroaching tides nip at their heels.

Now, the first national-level study of this competition reveals that coastal wetlands — among the country’s most valuable ecosystems, protecting infrastructure and providing homes for wildlife — are losing ground: 84% are gradually inundating, with many on track to transform into open water. Wetlands along the Gulf Coast are generally faring the worst while certain stretches of the Atlantic Coast appear more resilient. Some wetlands may be able to migrate inland or build up sediment fast enough to keep pace with sea level rise, perhaps with the right help from land managers.

“Our study provides wetland managers with new information to help them make better-informed decisions and identify meaningful solutions to issues they may be encountering, including to facilitate wetland migration upslope,” said Glenn Guntenspergen, a coastal wetland ecologist with the U.S. Geological Survey and senior author on the study.

The study will appear Monday, 3 August in Earth’s Future, AGU’s journal for research on the state of the planet and its inhabitants and their future resilience in the Anthropocene... (MORE - no ads)

https://www.sciencefocus.com/wellbeing/w...tal-health

EXCERPT: The University of Copenhagen psychiatrist discovered that, given free access to all the local rum they could guzzle, monkeys on the weight-loss drug drank significantly less than those given a placebo. Ozempic put a stopper in their drinking habits.

Why? The short answer is we don’t know, exactly. But we do know that, like the monkeys, some people on weight-loss jabs report drinking less.

Users of semaglutide (the general name for Ozempic and similar medications) say they also smoke or vape less. And they report having fewer nagging thoughts about food – otherwise known as ‘food noise’. But some users claim they’ve been left feeling flat, joyless or just a bit ‘meh’ on GLP-1s, a feeling that’s been labelled ‘anhedonia’. This figures if, as scientists suspect, they curb addiction.

At the same time, evidence is building for possible benefits to a broad range of psychiatric and neurological problems, from depression to dementia. While some of this sounds positive, there’s still so much we don’t know. For a start, semaglutide and other drugs classed as GLP-1s are only really tested in people with diabetes or obesity.

Would they be as safe and effective in those with mental health issues? How exactly do they work? And, crucially, how might they change our moods – and even our personalities?

The race is on to find the answers. And with so many already on the jabs – an estimated ten million in the US alone – there’s a lot of people’s mental health at stake... (MORE - details)

https://www.sciencealert.com/are-artific...t-explains

EXCERPTS: Artificial sweeteners are in the news almost constantly. If you believe the headlines, they are terrible blights on our health that are far worse than the sugar they replace. This isn't always supported by the evidence, but it's something that we love to hear, and so it gets reported on almost weekly regardless of what the data actually shows.

The most recent furor over artificial sweeteners is a perfect example. The headlines have been claiming for months that artificial sweeteners speed up cognitive decline. According to a recent study, there are six of these 'dangerous chemicals', including common ones like xylitol and aspartame, that may be causing our brains to rot more quickly.

[...] This is all made especially remarkable given that it doesn't really show any issues from artificial sweeteners at all. The study itself is a very simple piece of observational research. ... This research suffers from the normal issues that such observational studies do. One big thing is that food frequency questionnaires don't really measure intake of food. They measure what people THINK they eat, but we know that we are often unreliable historians.

[...] As letters to the journal have noted, there are also serious questions about the biological plausibility of the claim. ... This particular research therefore proves very little about artificial sweeteners and brain health. At worst, the study shows that there may be some negative impacts, although it depends on which analysis you choose to believe.

[...] Despite decades of fearmongering when it comes to artificial sweeteners, the reality is that they are very well-tested and generally not harmful... (MORE - missing details)

https://www.nytimes.com/2026/07/31/world...=url-share

EXCERPTS: Flying over the southwestern Amazon, archaeologists have discovered hundreds of ancient, monumental designs carved in the earth that hint at complex societies in the rainforest a millennium before Spanish and Portuguese colonists arrived.

The research, published this week in the journal Nature, shows circles, squares and other geometric figures, some with connecting roads, beneath the forest canopy, with nearly 400 previously unknown earthworks in all. Many are formations that archaeologists call geoglyphs and date from between 600 B.C. to 850 A.D. All of them add to evidence contradicting the depiction of the Amazon as a largely untouched expanse before the arrival of Europeans in the 15th century.

[...] The geoglyphs, shaped by embankments, mounds and trenches, vary in size. Most span seven acres, including many with ditches 30 feet wide and 15 feet deep. The biggest figure sprawls across more than 120 acres. [...] Dr. Pärssinen said the archaeologists had not found any evidence of permanent residence at the mounds from the Aquiry era, which ended around 900 A.D. Nor did they believe any were meant to be defensive structures.

But the structures, stretching across a zone of 1,700 square miles, build on evidence that the Amazon basin was widely and densely populated in the centuries before Columbus. Chroniclers like Gaspar de Carvajal, a missionary who traveled the Amazon in the 1540s with the conquistador Francisco de Orellana, described a land “thickly populated” in some places, with many large settlements, including one that “stretched for five leagues without there intervening any space from house to house.”

Those accounts were largely dismissed in the centuries that followed, given the crushing toll that disease and colonization took on Indigenous people. Scientists who followed also struggled to see how large or complex societies could develop without European-style agriculture, contributing to a false idea that the Amazon was a pristine forest, rather than one where the population was almost wiped out.

“Archaeologists find all of these things that are not supposed to be found in Amazonia, and it’s not because Amazonia is different in terms of the soil but how you use the forest,” Dr. Roosevelt said.

Recent work in other parts of the Amazon has found the traces of roads, canals, plazas and residential platforms, including in eastern Ecuador. Dr. Pärssinen’s team estimated that there may be thousands more earthworks in the region, and noted that the rainforest remains so dense in some places that even lasers could not pierce the foliage... (MORE - missing details)

https://youtu.be/AsIvMt2xbNo

https://www.youtube-nocookie.com/embed/AsIvMt2xbNo

RELATED: Midnight sun
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Cecilia Blomdahl
https://youtu.be/vbyZhGVKBEc

INTRO: It's been almost three months since the last sunset here on Svalbard, and now I'm definitely starting to feel it. The craziest part? We still have around 40 more days of 24-hour daylight ahead of us...

I can't tell what time it is anymore ... https://youtu.be/vbyZhGVKBEc

https://www.youtube-nocookie.com/embed/vbyZhGVKBEc