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Comment by Dr. Krishna Kumari Challa on February 13, 2021 at 8:56am

Birds can 'read' the Earth's magnetic signature well enough to get back on course

Birdwatchers get very excited when a 'rare' migratory bird makes landfall having been blown off-course and flown beyond its normal range. But these are rare for a reason; most birds that have made the journey before are able to correct for large displacements and find their final destination.

Now, new research by an international team shows for the first time, how birds displaced in this way are able to navigate back to their migratory route and gives us an insight into how they accomplish this feat. They describe how reed warblers can navigate from a 'magnetic position' beyond what they have experienced in their normal migration route, back towards that correct route.

Different parts of the Earth have a distinct 'geomagnetic signature' according to their location. This is a combination of the strength of the geomagnetic field, the magnetic inclination or the dip angle between magnetic field lines and the horizon and the magnetic declination, or the angle between directions to the geographic and magnetic North poles.

Adult birds already familiar with their migration route, and its general magnetic signatures, were held in captivity for a short period before being released back into the wild, and exposed to a simulation of the earth's magnetic signature at a location thousands of miles beyond the birds' natural migratory corridor. Despite remaining physically located at their capture site and experiencing all other sensory clues about their location, including starlight and the sights, smell and sounds of their actual location, the birds still showed the urge to begin their journey as though they were in the location suggested by the magnetic signal they were experiencing.

They oriented themselves to fly in a direction which would lead them 'back' to their migratory path from the location suggested to them by the magnetic signals they were experiencing.

This shows that the earth's magnetic field is the key factor in guiding reed warblers when they are blown off course. The overriding impulse was to respond to the magnetic information they were receiving. current work shows is that birds are able to sense that they are beyond the bounds of the magnetic fields that are familiar to them from their year-round movements, and are able to extrapolate their position sufficiently from the signals. This fascinating ability enables bird to navigate towards their normal migration route.

What these birds are achieving is "true navigation". In other words, they are able to return to a known goal after displacement to a completely unknown location without relying on familiar surroundings, cues that emanate from the destination, or information collected during the outward journey.

But questions remain about whether the birds have an accurate 'map' or are just using a 'rule of thumb' measurement to judge the general direction of travel needed to get back on course.

"Navigation by extrapolation of geomagnetic cues in a migratory songbird" Current Biology, DOI: 10.1016/j.cub.2021.01.051

https://phys.org/news/2021-02-birds-earth-magnetic-signature.html?u...

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Comment by Dr. Krishna Kumari Challa on February 13, 2021 at 7:02am

Scientists Think They've Figured Out What's Triggering Brain Fog in COVID-19 Patients
Not long after the first wave of COVID-19 infections hit, doctors all around the world began to notice something strange – a host of lingering effects persisting in patients, long after they appeared to have otherwise recovered from the virus.

These unusual neurological symptoms – encompassing fatigue, memory loss, confusion, and other abnormalities – are sometimes known as 'brain fog' or 'COVID brain', and new research may have identified an underlying cause of the condition.

As part of the new study, researchers screened the cerebrospinal fluid of 18 cancer patients who were experiencing neurological dysfunction (aka encephalopathy) after having been infected with the SARS-CoV-2 virus.

Initially, it was suspected that an ongoing viral infection might be the cause of their brain fog symptoms, but microbiological analysis of fluid taken in spinal taps did not reveal any sign of the virus, suggesting the patients had recovered from COVID-19.

They found that these patients had persistent inflammation and high levels of cytokines in their cerebrospinal fluid, which explained the symptoms they were having.

Cytokines are a broad category of proteins that are involved with signalling in the immune system.

In some cases of coronavirus, an over-production of these molecules results in what's known as a cytokine storm, which can cause excessive inflammation and is potentially deadly.

A similar phenomenon showing high levels of inflammatory cytokines is sometimes seen as a side effect of chimeric antibody receptor (CAR) T cell therapy, an immunotherapy treatment, which can also produce confusion, delirium, and other neurological effects that bear a resemblance to COVID brain fog.

The thinking is that the flood of these inflammatory chemicals in the immune system seeps into the brain, producing symptoms of encephalopathy as seen in patients. 

The findings here suggest anti-inflammatory drugs might be helpful in mitigating brain fog in patients, and could highlight new directions in terms of diagnosing this strange, lingering malaise.

Researchers used to think that the nervous system was an immune-privileged organ, meaning that it didn't have any kind of relationship at all with the immune system.

But the more scientists looked, the more the connections connections between the two were found.

https://www.cell.com/cancer-cell/fulltext/S1535-6108(21)00051-9

https://www.sciencealert.com/scientists-may-have-identified-what-ca...

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 10:28am

Human Cells Can Synthesize DNA in Their Cytoplasm

While studying a degenerative eye disease, researchers find the first evidence that cells produce endogenous DNA in the cytoplasm. Drugs that block this activity are linked with reduced risk of atrophic age-related macular degeneration.

Over the past decade, there have been scattered reports of mammalian cells’ own DNA being found in the cytoplasm, mainly in the context of disease and aging. While it is not unusual to find DNA from an invading organism there, the presence of an organism’s own genetic code—in the form of complementary DNA (cDNA) synthesized from an RNA template—has puzzled scientists. In each case, the cDNA has come from endogenous retrotransposons, known for their copy-and-paste mechanism that results in the insertion of new copies of themselves into the genome. This process typically takes place in the nucleus, so the cytoplasmic cDNA lacked an explanation.

After detecting cDNA of Alu, the most abundant retrotransposon in the human genome, in the cytoplasm of cells modeling a degenerative eye disease, University of Virginia ophthalmologist Jayakrishna Ambati and his colleagues decided to investigate its mysterious origin. Their results, reported February 1 in PNAS, reveal that human cells can actually synthesize cDNA of Alu in the cytoplasm.

S. Fukuda et al., “Cytoplasmic synthesis of endogenous Alu complementary DNA via reverse transcription and implications in age-related macular degeneration,” PNAS, doi:10.1073/pnas.2022751118, 2021.

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 10:13am

An Optical Coating Like No Other

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 10:09am

Synchronization of brain hemispheres changes what we hear

How come we don’t hear everything twice: After all, our ears sit on opposite sides of our head and most sounds do not reach both our ears at exactly the same time. While this helps us determine which direction sounds are coming from, it also means that our brain has to combine the information from both ears. Otherwise, we would hear an echo.

In addition, input from the right ear reaches the left brain hemisphere first, while input from the left ear reaches the right brain hemisphere first. The two hemispheres perform different tasks during speech processing: The left side is responsible for distinguishing phonemes and syllables, whereas the right side recognizes the speech prosody and rhythm. Although each hemisphere receives the information at a different time and processes different features of speech, the brain integrates what it hears into a unified speech sound.

The exact mechanism behind this integration process was not known until now. 

Now researchers have managed to demonstrate that the process of integrating what we hear is directly linked to synchronization by gamma waves.

During the experiments, the researchers disrupted the natural activity pattern of gamma waves by stimulating both hemispheres of the brain with electrodes attached to the head. This manipulation affected participants’ ability to correctly identify the syllable they heard. The fMRI analysis showed that there were also changes in the activity of the neural connections between the right and the left brain hemispheres: The strength of the connection changed depending on whether the rhythm of the gamma waves was influenced by electric stimulation in the two brain hemispheres synchronously or asynchronously. This disruption also impaired the integration process. Thus, synchronization of the gamma waves seems to serve to balance the different inputs from the two hemispheres of the brain, providing a unified auditory impression.

These findings could thus also find clinical application in the near future. “Previous studies show that disturbances in the connection between the two hemispheres of the brain are associated with auditory phantom perceptions such as tinnitus and auditory verbal hallucinations. Thus, electric brain stimulation may present a promising avenue for the development of therapeutic interventions.

Preisig BC, Riecke L, Sjerps M, Kösem A, Kop BR, Bramson B, Hagoort P, Hervais-Adelman A. Selective modulation of interhemispheric connectivity by transcranial alternating current stimulation influences binaural integration. PNAS, 2021 DOI: 10.1073/pnas.2015488118

https://www.sciencedaily.com/releases/2021/02/210208173103.htm#:~:t....

https://researchnews.cc/news/5061/Synchronization-of-brain-hemisphe...

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 9:08am

A reeking, parasitic plant lost its body and much of its genetic blueprint

The genome of Sapria himalayana is rife with gene loss and theft

New research on the genetic instruction book of a rare plant Sapria genus reveals the lengths to which it has gone to become a specialized parasite. The findings, published January 22 in Current Biology, suggest that at least one species of Sapria has lost nearly half of the genes commonly found in other flowering plants and stolen many others directly from its hosts. 

The plant’s rewired genetics echo its bizarre biology. Sapria and its relatives in the family Rafflesiaceae have discarded their stems, roots and any photosynthetic tissue.

About 44 percent of the genes found in most flowering plants were missing in S. himalayana. Yet, at the same time, the genome is about 55,000 genes long, more than that of some other nonparasitic plants. The count is inflated by many repeating segments of DNA, the team found.

Loss of the chlorophyll pigments responsible for photosynthesis is common in parasitic plants that rely on their hosts for sustenance. But S. himalayana appears to have even scrapped all genetic remnants of its chloroplasts, the cellular structures where photosynthesis occurs. 

Chloroplasts have their own genome, distinct from the nuclear genome that runs a plant’s cells and the mitochondria that produce energy for the cells. S. himalayana seems to have lost this genome altogether, suggesting that the plant has purged the last remnants of its ancestral life that allowed it to make its own food.

even genes in S. himalayana’s nuclear genome that would regulate components of the chloroplast genome have vanished. 

Among the remaining parts of the nuclear genome, it was  also found that more than 1 percent of S. himalayana’s genome comes from genes stolen from other plants, likely its current and ancestral hosts.

The new discovery illustrates the level of commitment S. himalayana and its relatives have given to evolving a parasitic lifestyle

https://www.cell.com/current-biology/fulltext/S0960-9822(20)31897-2?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982220318972%3Fshowall%3Dtrue

https://www.sciencenews.org/article/reeking-parasitic-sapria-plant-...

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 9:02am

Reconstructing Molecules in Motion

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 8:16am

Our Milky Way galaxy is a spiral galaxy. It evolved into its flat disk shape over billions of years. But astronomers have discovered a distant and young galaxy that has a remarkably similar shape.

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 8:10am

Air pollution caused 1 out of 5 deaths in 2018—that's more than 8 million, study says

Microscopic, and sometimes larger, particles of soot, smoke and dust that spew out of gas-guzzling factories, ships, cars and aircraft are responsible for 18% of total global deaths in 2018—that equals more than 8 million people, a new study found.

That number far surpasses previous estimates of the amount of people killed globally by all types of air pollution, including dust and smoke from wildfires and agricultural burns. The most widely accepted estimate stands at 4.2 million.

https://phys.org/news/2021-02-air-pollution-deaths-2018that-million...

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How microplastics in the soil contribute to environmental pollution

Plastic, with its unabated global production, is a major and persistent contributor to environmental pollution. In fact, the accumulation of plastic debris in our environment is only expected to increase in the future. "Microplastics" (MP)—plastic debris

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A new way of forming planets

In the last 25 years, scientists have discovered over 4000 planets beyond the borders of our solar system. From relatively small rock and water worlds to blisteringly hot gas giants, the planets display a remarkable variety. This variety is not unexpected. The sophisticated computer models, with which scientists study the formation of planets, also spawn very different planets. What the models have more difficulty to explain is the observed mass distribution of the planets discovered around other stars. The majority have fallen into the intermediate mass category—planets with masses of several Earth masses to around that of Neptune. Even in the context of the solar system, the formation of Uranus and Neptune remains a mystery. Scientists of the Universities of Zurich and Cambridge, associated with the Swiss NCCR PlanetS, have now proposed an alternative explanation backed up by comprehensive simulations. Their results were published in the scientific journal Nature Astronomy.

Comment by Dr. Krishna Kumari Challa on February 12, 2021 at 8:07am

Tiny microorganisms in the Southern Ocean affect how the rest of the world's seas respond to carbon

In the ocean that surrounds Antarctica, deep water wells up to the surface, carrying nutrients and other dissolved materials needed by light-loving ocean life. One of these materials is calcium carbonate, which, when dissolved, raises seawater alkalinity and helps the ocean respond to increasing carbon dioxide levels. Ocean currents carry this alkalinity-enriched water northward—unless tiny organisms intercept it and trap the alkalinity in the Southern Ocean.

Plankton in the Southern Ocean capture upwelled alkalinity to make protective shells composed of calcium carbonate. When the plankton die, their calcified shells sink and break down, returning the alkalinity to deep waters, from where it can well up again. If calcifying organisms are not very active, more high-alkalinity water escapes northward, allowing the global ocean to absorb more carbon dioxide. If, on the other hand, the calcifying plankton quickly use alkalinity that rises to the surface, this cycle traps alkalinity in the Southern Ocean.

Researchers recently  demonstrated this process through model simulations, showing that calcification in the Southern Ocean affects how alkalinity spreads around the world.

In general, more calcifying activity traps alkalinity in the Southern Ocean, but certain conditions limit the main phytoplankton responsible. For instance, high levels of silicic acid and iron might favor silicon-shelled microorganisms over calcium carbonate-shelled ones, allowing more alkalinity to flow out to other oceans. High ocean acidity may also cause problems for calcifying organisms.

The researchers note that after an interruption in calcification in the Southern Ocean, increases in alkalinity reached some subtropical regions within 10 years. The alkalinity irregularity took longer to reach more northerly oceans, gradually becoming more apparent the longer that Southern Ocean calcification was suppressed. On millennial timescales, the authors say, the activity of tiny southern plankton has the potential to influence global climate.

 K. M. Krumhardt et al. Southern Ocean Calcification Controls the Global Distribution of Alkalinity, Global Biogeochemical Cycles (2020). DOI: 10.1029/2020GB006727

https://phys.org/news/2021-02-tiny-microorganisms-southern-ocean-af...

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