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Comment by Dr. Krishna Kumari Challa on October 7, 2021 at 9:30am

How 'ice needles' weave patterns of stones in frozen landscapes

Nature is full of repeating patterns that are part of the beauty of our world. An international team, including a researcher from the University of Washington, used modern tools to explain repeating patterns of stones that form in cold landscapes.

The new study, published Oct. 5 in the Proceedings of the National Academy of Sciences, uses experimental tools to show how needles of ice growing randomly on frozen ground can gradually move rocks into regular, repeating patterns. The team, based mainly in China and Japan, uses a combination of novel experiments and computer modeling to describe these striking features with new theoretical insights.

"The presence of these amazing patterns that develop without any intervention from humans is pretty striking in nature.

One of the reasons for the patterns is needle ice. As the temperature drops, the moisture contained in the soil grows into spikes of ice crystals that protrude from the ground.

"When you go out in the backyard after a freezing night and you feel a little crunch under the foot, you're probably walking on needle ice.

As needle ice forms it tends to push up soil particles, and if there are any, small stones. More needle ice can form on patches of bare soil compared to rock-covered areas. The ice needles will slightly displace any remaining stones in the barer region. Over years, the stones begin to cluster in groups, leaving the bare patches essentially stone-free.

That kind of selective growth involves interesting feedbacks between the size of the stones, the moisture in the soil and the growth of the ice needles.

Watch a video that shows how this happens here:

https://movie-usa.glencoesoftware.com/video/10.1073/pnas.2110670118...

Anyuan Li et al, Ice needles weave patterns of stones in freezing landscapes, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2110670118

https://www.washington.edu/news/2021/10/06/how-ice-needles-weave-pa...

Comment by Dr. Krishna Kumari Challa on October 7, 2021 at 9:05am

Second, fallout from biomass burning is rich in micronutrients such as iron. Phytoplankton growth in much of the Southern Ocean is nutrient-limited so the increased fallout from Māori burning probably resulted in centuries of enhanced phytoplankton growth in large areas of the Southern Hemisphere.

Third, the results refine what is known about the timing of the arrival of the Māori in New Zealand, one of the last habitable places on earth to be colonized by humans. Māori arrival dates based on radiocarbon dates vary from the 13^th to 14^th century, but the more precise dating made possible by the ice core records pinpoints the start of large scale burning by early Māori in New Zealand to 1297, with an uncertainty of 30 years.

"From this study and other previous work this team has done such as on 2,000-year old lead pollution in the Arctic from ancient Rome, it is clear that ice core records are very valuable for learning about past human impacts on the environment. "Even the most remote parts of Earth were not necessarily pristine in preindustrial times."

Hemispheric black carbon increase after the 13th-century Māori arrival in New Zealand, Nature (2021). DOI: 10.1038/s41586-021-03858-9

https://phys.org/news/2021-10-early-human-impacted-earth-atmosphere...

Part 3

Comment by Dr. Krishna Kumari Challa on October 7, 2021 at 9:04am

After consulting paleofire records from each of the three regions, only one viable possibility remained: New Zealand, where charcoal records showed a major increase in fire activity beginning about the year 1300. This date also coincided with the estimated arrival, colonization, and subsequent burning of much of New Zealand's forested areas by the Māori people.

This was a surprising conclusion, given New Zealand's relatively small land area and the distance (nearly 4,500 miles), that smoke would have travelled to reach the ice core site on James Ross Island.

"Compared to natural burning in places like the Amazon, or Southern Africa, or Australia, you wouldn't expect Māori burning in New Zealand to have a big impact, but it does over the Southern Ocean and the Antarctic Peninsula

--

The study findings are important for a number of reasons. First, the results have important implications for our understanding of Earth's atmosphere and climate. Modern climate models rely on accurate information about past climate to make projections for the future, especially on emissions and concentrations of light-absorbing black carbon linked to Earth's radiative balance. Although it is often assumed that human impacts during preindustrial times were negligible compared to background or natural burning, this study provides new evidence that emissions from human-related burning have impacted Earth's atmosphere and possibly its climate far earlier, and at scales far larger, than previously imagined.

part2

Comment by Dr. Krishna Kumari Challa on October 7, 2021 at 9:03am

Early human activities impacted Earth's atmosphere more than previously known

Did you think only industrial era impacted Earth's atmosphere? Then think again. Because ....

Several years ago, while analyzing ice core samples from Antarctica's James Ross Island, scientists noticed something unusual: a substantial increase in levels of black carbon that began around the year 1300 and continued to the modern day.

Black carbon, commonly referred to as soot, is a light-absorbing particle that comes from combustion sources such as biomass burning (e.g. forest fires) and, more recently, fossil fuel combustion. Working in collaboration with an international team of scientists from the United Kingdom, Austria, Norway, Germany, Australia, Argentina, and the U.S., McConnell, Chellman, and Mulvaney set out to uncover the origins of the unexpected increase in black carbon captured in the Antarctic ice.

The team's findings, which published this week in Nature, point to an unlikely source: ancient Māori land-burning practices in New Zealand, conducted at a scale that impacted the atmosphere across much of the Southern Hemisphere and dwarfed other preindustrial emissions in the region during the past 2,000 years.

The idea that humans at this time in history caused such a significant change in atmospheric black carbon through their land clearing activities is quite surprising.

We used to think that if you went back a few hundred years you'd be looking at a pristine, pre-industrial world, but it's clear from this study that humans have been impacting the environment over the Southern Ocean and the Antarctica Peninsula for at least the last 700 years.

To identify the source of the black carbon, the study team analyzed an array of six ice cores collected from James Ross Island and continental Antarctica using DRI's unique continuous ice-core analytical system. The method used to analyze black carbon in ice was first developed in McConnell's lab in 2007.

While the ice core from James Ross Island showed a notable increase in black carbon beginning around the year 1300, with levels tripling over the 700 years that followed and peaking during the 16^th and 17^th centuries, black carbon levels at sites in continental Antarctica during the same period of time stayed relatively stable.

Part 1

Comment by Dr. Krishna Kumari Challa on October 7, 2021 at 8:45am

Nobel in chemistry honors 'greener' way to build molecules

Two scientists won the Nobel Prize in chemistry Wednesday for finding an ingenious and environmentally cleaner way to build molecules—an approach now used to make a variety of compounds, including medicines and pesticides.

The work of Benjamin List and David W.C. MacMillan has allowed scientists to produce those molecules more cheaply, efficiently, safely and with significantly less hazardous waste.

It's already benefiting humankind greatly. It was the second day in a row that a Nobel rewarded work that had environmental implications.

Announcement of the 2021 Nobel Prize in Chemistry

Comment by Dr. Krishna Kumari Challa on October 6, 2021 at 11:54am

Personalized Deep Brain Stimulation Therapy (DBS)

Health physicians have successfully treated a patient with severe depression by tapping into the specific brain circuit involved in depressive brain patterns and resetting them using the equivalent of a pacemaker for the brain.

Comment by Dr. Krishna Kumari Challa on October 6, 2021 at 11:01am

PLOS Pathogens to offer authors seamless data deposition to Dryad

The Public Library of Science (PLOS) today announced that PLOS Pathogens is introducing a new technology solution that makes depositing data simpler and more accessible for our authors. As part of a one-year trial beginning October 5, 2021, PLOS Pathogens authors now have the option to upload their data files directly to Dryad Digital Repository (https://datadryad.org/stash/) during manuscript submission or revision—without even leaving our submission system. PLOS Pathogens is among the first journals in our field to offer this new service. Thanks to a grant from the Wellcome Trust (https://plos.io/3oAOeiu), datasets that are part of the trial will be hosted in perpetuity at no cost to authors.

Researchers rely on access to scientific data to enhance their understanding of published research, for purposes of verification, replication and reanalysis, to guide future investigations, and to inform systematic reviews or meta-analyses. Depositing data in a repository (as opposed to offering it upon request or publishing as Supporting Information) further prevents data loss, improves discoverability, and removes barriers to replication and reuse. This new integrated solution means that it takes just minutes to upload a dataset and receive a unique, citable Dryad DOI. If a manuscript is accepted for publication, the associated dataset will undergo Dryad’s screening and curatorial process and become public on the site, with links to and from the published research article.

Data repositories like Dryad offer important advantages, including data preservation and tracking, facilitating reproducibility, demonstrating rigor, and attracting citations. This integration offers a simple, intuitive interface that makes depositing data with Dryad a part of our authors' normal submission workflow. The process is no more challenging than uploading data as Supporting Information, but much more effective as a vehicle for sharing. The year-long trial will show whether a more streamlined process inspires authors to take advantage of the benefits of a data repository.

https://datadryad.org/stash/

https://www.eurekalert.org/news-releases/930457

Comment by Dr. Krishna Kumari Challa on October 6, 2021 at 10:39am

Age and aging have critical effects on the gut microbiome

Researchers have found that aging produces significant changes in the microbiome of the human small intestine distinct from those caused by medications or illness burden. The findings were published in the journal Cell Reports.

By teasing out the microbial changes that occur in the small bowel with age, medication use and diseases, researchers hope to identify unique components of the microbial community to target for therapeutics and interventions that could promote healthy aging.

Research exploring the gut microbiome, and its impact on health, has relied predominantly on fecal samples, which do not represent the entire gut. So  in their present study, investigators analyzed samples from the small intestine for examination of the microbiome and its relationship with aging.

This study is the first of its kind to examine the microbial composition of the small intestine of subjects 18 years of age to 80. Scientists now know that certain microbial populations are influenced more by medications, while others are more affected by certain diseases. Now researchers have identified specific microbes that appear to be only influenced by the chronological age of the person.

The 21st century has been referred to as the "era of the gut microbiome" as scientists turn considerable attention to the role trillions of gut bacteria, fungi and viruses may play in human health and disease. The microbiome is the name given to the genes that live in these cells. Studies have suggested that disturbances in the constellations of the microbial universe may lead to critical illnesses, including gastroenterological diseases, diabetes, obesity, and some neurological disorders.

While researchers know that microbial diversity in stool decreases with age, investigators now identified bacteria in the small bowel they refer to as "disruptors" that increase and could be troublesome.
Coliforms are normal residents of the intestine. They found that when these rod-shaped microbes become too abundant in the small bowel–as they do as we get older–they exert a negative influence on the rest of the microbial population. They are like weeds in a garden.

Investigators also found that as people age, the bacteria in the small intestine change from microbes that prefer oxygen to those that can survive with less oxygen, something they hope to understand as the research continues.

Gabriela Leite, Mark Pimentel, Gillian M. Barlow, Christine Chang, Ava Hosseini, Jiajing Wang, Gonzalo Parodi, Rashin Sedighi, Ali Rezaie, Ruchi Mathur. Age and the aging process significantly alter the small bowel microbiome. Cell Reports, 2021; 36 (13): 109765 DOI: 10.1016/j.celrep.2021.109765

https://researchnews.cc/news/9274/Age-and-aging-have-critical-effec...

Comment by Dr. Krishna Kumari Challa on October 6, 2021 at 9:57am

New study uncovers brain circuits that control fear responses

Researchers  have discovered a brain mechanism that enables mice to override their instincts based on previous experience.

The study, published today in Neuron, identifies a new brain circuit in the ventral lateral geniculate nucleus (vLGN), an inhibitory structure in the brain. The neuroscientists found that when activity in this brain region was suppressed, animals were more likely to seek safety and escape from perceived danger, whereas activation of vLGN neurons completely abolished escape responses to imminent threats.

While it is normal to experience fear or anxiety in certain situations, we can adjust our fear responses depending on our knowledge or circumstances. For example, being woken up by loud blasts and bright lights nearby might evoke a fear reaction. But if you have experienced fireworks before, your knowledge will likely prevent such reactions and allow you to watch without fear. On the other hand, if you happen to be in a war zone, your fear reaction might be strongly increased.

While many brain regions have previously been shown to be involved in processing perceived danger and mediating fear reactions, the mechanisms of how these reactions are controlled are still unclear. Such control is crucial since its impairment can lead to anxiety disorders such as phobias or post-traumatic stress disorders (PTSD), in which the circuits in the brain associated with fear and anxiety are thought to become overactive, leading to pathologically increased fear responses.

The new study took advantage of an established experimental paradigm in which mice escape to a shelter in response to an overhead expanding dark shadow. This looming stimulus simulates a predator moving towards the animal from above.

The researchers found that the vLGN could control escape behavior depending on the animal's knowledge gained through previous experience, and on its assessment of risk in its current environment. When mice were not expecting a threat and felt safe, the activity of a subset of inhibitory neurons in the vLGN was high, which in turn could inhibit threat reactions. In contrast, when mice expected danger, activity in these neurons was low, which made the animals more likely to escape and seek safety.

vLGN specifically inhibits neurons in the superior colliculus that respond to visual threats and thereby specifically blocks the pathway in the brain that mediates reactions to such threats—something the animal sees that could pose a danger like an approaching predator.

Flexible inhibitory control of visually-evoked defensive behaviour by the ventral lateral geniculate nucleus, Neuron (2021). DOI: 10.1016/j.neuron.2021.09.003

https://medicalxpress.com/news/2021-10-uncovers-brain-circuits-resp...

Comment by Dr. Krishna Kumari Challa on October 6, 2021 at 9:06am

Within the environment of the nucleus, it would make sense that genes regulated by the same type of information would be concentrated in close proximity so that they might share resources, potentially lowering the energetic cost of regulation. Several previous experiments have shown a level of organization in the nucleus where genes occupy discrete domains. However, many of these studies use biochemical methods to define domains, rather than actually observing the physical position of the active genes within the nucleus.

In the Current Biology study, the researchers demonstrated that they could accurately identify the physical position of the active genes using a microscopy imaging procedure and fruit flies, a model organism commonly used in genetic and molecular research. The researchers examined how a fertilized fruit fly egg develops into a fully formed organism, a process that requires the activity of sets of genes, which become progressively activated during embryonic development.

Focusing on the earliest set of genes appearing in 90-minute-old fruit fly embryos, the researchers observed how a protein called Zelda regulates the genes' transcription by recruiting the enzyme RNA Polymerase II (Pol-II). Using high resolution microscopy and antibody staining, they visualized Pol-II at sites of nascent transcription on chromosomes.

By observing the positions of many genes using this method, they asked the question: Are genes found in clusters? The answer was no.

The researchers performed a series of follow-up experiments to test the notion of functional clustering, such as looking for gene expression changes when genes were found in close proximity, or signs of resources being shared among the genes visualized. Once again, they did not find evidence of clustering.

In contrast to the idea that genes are spatially clustered and share transcriptional resources—what one might call a "collectivist" model—the authors conclude that the data support an "individualist" model of gene control at early genome activation in fruit flies.

Spatial organization of transcribing loci during early genome activation in Drosophila, Current Biology (2021). DOI: 10.1016/j.cub.2021.09.027

https://phys.org/news/2021-10-genes-individualists-collectivists-ea...

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