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Comment by Dr. Krishna Kumari Challa on November 13, 2021 at 11:36am

For this study, the researchers compiled an exhaustive list of all bird species that have been present in nine different archipelagos* before and after human-caused extinctions occurred. This covered 1,302 bird species, including 265 globally or locally extinct, and 355 established introductions from 143 separate species. In addition, the scientists visited different museum collections, including the Natural History Museum, to measure several morphological traits in skin or skeleton specimens. With this data, the researchers were able to quantify the trait diversity before and after bird extinctions, and identify the ecological niches extinct birds once filled.

The research team found that before human arrival, island bird communities were more morphologically diverse than they are today. Their findings show how human-driven extinctions have disproportionally affected some types of birds (for example, larger birds and flightless birds are more likely to go extinct), leading to the loss of certain ecological roles.

The researchers also found that different archipelagos are becoming more and more similar in terms of trait diversity as native birds go extinct and the same kind of alien species are being newly established in many places.

https://phys.org/news/2021-11-birds-roles-human-caused-extinct-spec...

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Comment by Dr. Krishna Kumari Challa on November 13, 2021 at 11:35am

Introduced birds are not replacing roles of human-caused extinct species: study

Human-caused bird extinctions are driving losses of functional diversity on islands worldwide, and the gaps they leave behind are not being filled by introduced (alien) species, finds a new study.

The study, published in Science Advances, shows how human impacts such as habitat destruction and climate change are impoverishing ecosystems, even on islands where alien birds actually outnumber the species that have gone extinct.

Humans have drastically changed bird communities, not only by driving animals to extinction but also by introducing species into new habitats across the globe. There has been some debate as to whether introduced species might replace the roles of the extinct species, thus maintaining functional diversity within the ecosystem; here, researchers found that is unfortunately not the case.

 Valuable functions that may be lost with bird extinctions can include pollination and seed dispersal, which can have cascading harmful effects on other species.

Some groups of birds have been particularly successful at establishing outside their natural areas—for example, many species of parrot and starling. Because of this, islands are becoming more homogeneous as the same kind of birds are established everywhere.

These new  findings add to evidence that conservation efforts should be focused on preserving functionally distinct threatened species, to stem the tide of harmful losses to biodiversity that are driven by human actions. Huge numbers of species are being driven to extinction by human-driven effects such as habitat loss and climate change, so it is vital that we act now to reduce our negative impact on global biodiversity.

 Ferran Sayol, Loss of functional diversity through anthropogenic extinctions of island birds is not offset by biotic invasions, Science Advances (2021). DOI: 10.1126/sciadv.abj5790. www.science.org/doi/10.1126/sciadv.abj5790

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Comment by Dr. Krishna Kumari Challa on November 12, 2021 at 2:11pm

The Matilda effect is a bias against acknowledging the achievements of those women scientists whose work is attributed to their male colleagues. This effect was first described by suffragist and abolitionist Matilda Joslyn Gage (1826–98) in her essay, "Woman as Inventor" (first published as a tract in 1870 and in the North American Review in 1883). The term "Matilda effect" was coined in 1993 by science historian Margaret W. Rossiter. Rossiter provides several examples of this effect. Trotula (Trota of Salerno), a 12th-century Italian woman physician, wrote books which, after her death, were attributed to male authors. Nineteenth- and twentieth-century cases illustrating the Matilda effect include those of Nettie Stevens, Lise Meitner, Marietta Blau, Rosalind Franklin, and Jocelyn Bell Burnell. The Matilda effect was compared to the Matthew effect, whereby an eminent scientist often gets more credit than a comparatively unknown researcher, even if their work is shared or similar.

https://en.wikipedia.org/wiki/Matilda_effect

Comment by Dr. Krishna Kumari Challa on November 12, 2021 at 1:33pm

Researchers think that humans have evolved out of this building plan that was previously restricting the size of cortex, and they figured out a way to become more energetically efficient, so you spend less ATP [energy molecules] per volume compared to other species."

This finding reveals, the researchers said, an intriguing avenue for further investigation. In future research, the team hopes to explore the evolutionary pressures that might have led to this difference, and isolate where, exactly, that extra brain energy is going.

The research has been published in Nature.

https://www.nature.com/articles/s41586-021-04072-3

https://www.sciencealert.com/we-ve-just-found-a-fascinating-differe...

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Part 3

Comment by Dr. Krishna Kumari Challa on November 12, 2021 at 1:32pm

When comparing the brains of the two species, the researchers found that the human dendrites had a marked lower density of these ion channels compared to rat dendrites. This was worth investigating further.

The new research has been expanded to include 10 species: shrew, mouse, gerbil, rat, ferret, guinea pig, rabbit, marmoset, macaque and, of course, human, using samples of tissue excised from epilepsy patients during brain surgery.

An analysis of the physical structure of these brains revealed that ion channel density increases with neuron size, with one notable exception: the human brain.

This, the researchers concluded, was to maintain ion channel density across a range of brain sizes; so, although the shrew had a higher number of neurons than the rabbit or the macaque in a given volume of brain, the density of ion channels in that volume was consistent.

"This building plan is consistent across nine different mammalian species. What it looks like the cortex is trying to do is keep the numbers of ion channels per unit volume the same across all the species. This means that for a given volume of cortex, the energetic cost is the same, at least for ion channels.

The exceptionally low ion channel density in the human brain was glaring, when compared with all the other brains.

All the comparison animals were significantly smaller than humans, of course, so it may be worth testing the samples of even larger animals. However, the macaque is often used in research as a model for the human brain.

The researchers suspect an evolutionary trade-off is possible for humans – this is when a biological system loses or diminishes a trait for an optimization elsewhere.

For example, it takes energy to pump ions through dendrites. By minimizing ion channel density, the human brain may have been able to deploy the energy savings elsewhere – perhaps in more complex synaptic connections, or more rapid action potentials.

"If the brain can save energy by reducing the density of ion channels, it can spend that energy on other neuronal or circuit processes

Part 2

Comment by Dr. Krishna Kumari Challa on November 12, 2021 at 1:30pm

There's a Strange Difference Between Human Brains And Those of Other Mammals

When it comes to the world of mammals, humans tend to stand out a fair bit.

While many animals share some aspects of our intelligence, they don't take it to the same level we have. But pinning down why we're more cognitively advanced on a neurological level has been tricky; to date, studies have found no significant differences between the brains of mammals. Now, we finally have a lead.

A team of researchers from the Massachusetts Institute of Technology (MIT) has found that, compared to other mammals, human brains have a much lower number of the neuronal channels that allow the flow of ions such as calcium, potassium, and sodium.

This flow produces the electrical impulses that allow neurons to communicate with each other; having fewer of them could mean that the human brain can operate more efficiently, diverting resources to more complex cognitive functions.

One of their findings concerned dendrites, the branching structures at the tips of nerve cells through which the brain's electrical impulses are received via ion channels. From here, the dendrite generates what we call an action potential, which transfers the signal onwards.

Part 1

Comment by Dr. Krishna Kumari Challa on November 12, 2021 at 1:24pm

Study Finds Fish Rubbing Up Against Their Predators — Sharks. Researchers suggest this behaviour plays a greater ecological role than previously known

Comment by Dr. Krishna Kumari Challa on November 12, 2021 at 1:20pm

Second instance of canine coronavirus found in a person

 A University of Florida research team is helping to build the case that coronaviruses move between animals and people at a more frequent rate than previously understood. Earlier this year, the team reported the first known instance of a coronavirus common in pigs to have "spilled over" into people. Spillovers refer to events where a virus that is adapted to a certain kind of host—say, a dog, or pig—acquires features that allow it to infect an entirely different species of host, such as a person. In their newest work, the team retrospectively uncovered an instance where a coronavirus known from dogs, called a canine coronavirus, infected at least one person visiting Haiti in early 2017. The infected person had a mild illness with fever and fatigue. The new work published in Clinical Infectious Diseases on Oct. 28,2021. In an unusual twist, the virus was determined to closely match a canine coronavirus reported earlier in 2021.

Comment by Dr. Krishna Kumari Challa on November 12, 2021 at 12:37pm

Scientists appeal for immediate climate action at COP26

More than 200 scientists told the COP26 summit Thursday to take immediate action to halt global warming, warning in an open letter that some climate change impacts were "irreversible" for generations.

The central task of the Glasgow meeting is to implement the Paris Agreement, with its goal of limiting temperature rise to between 1.5 and 2 degrees Celsius above pre-industrial levels.

But as negotiations enter their final days, commitments made so far could still lead to "catastrophic" warming of as much as 2.7C by 2100, according to the UN.

"We, climate scientists, stress that immediate, strong, rapid, sustained and large-scale actions are necessary," to keep warming within the Paris target, said the letter, signed by researchers across the world.

In August, a bombshell "code red" report from the world's top climate science body, the Intergovernmental Panel on Climate Change (IPCC), warned that Earth's average temperature will hit the 1.5C threshold around 2030, a decade earlier than projected only three years ago.

To keep from overshooting that temperature target the IPCC says emissions must fall 45 percent this decade.

Thursday's open letter, signed by some of the IPCC's report authors, calls on delegates in Glasgow to "fully acknowledge" the scientific evidence they have compiled of the severe threats posed by climate change.

"Cumulative greenhouse gas emissions to date already commit our planet to key changes of the climate system affecting human society and marine and terrestrial ecosystems, some of which are irreversible for generations to come," said the letter.

https://phys.org/news/2021-11-scientists-appeal-climate-action-cop2...

Comment by Dr. Krishna Kumari Challa on November 12, 2021 at 12:27pm

Once connected to the receptors, the moving molecules trigger two cascading signals, both of which are critical to spinal cord repair. One signal prompts the long tails of neurons in the spinal cord, called axons, to regenerate. Similar to electrical cables, axons send signals between the brain and the rest of the body. Severing or damaging axons can result in the loss of feeling in the body or even paralysis. Repairing axons, on the other hand, increases communication between the body and brain.

The second signal helps neurons survive after injury because it causes other cell types to proliferate, promoting the regrowth of lost blood vessels that feed neurons and critical cells for tissue repair. The therapy also induces myelin to rebuild around axons and reduces glial scarring, which acts as a physical barrier that prevents the spinal cord from healing.

The signals used in the study mimic the natural proteins that are needed to induce the desired biological responses. While the new therapy could be used to prevent paralysis after major trauma (automobile accidents, falls, sports accidents and gunshot wounds) as well as from diseases, researchers think the underlying discovery—that "supramolecular motion" is a key factor in bioactivity—can be applied to other therapies and targets.

Zaida Alvarez et al, Bioactive Scaffolds with Enhanced Supramolecular Motion Promote Recovery from Spinal Cord Injury, Science (2021). DOI: 10.1126/science.abh3602. www.science.org/doi/10.1126/science.abh3602

https://medicalxpress.com/news/2021-11-molecules-successfully-sever...

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