Comment

Comment by Dr. Krishna Kumari Challa on October 10, 2020 at 5:30am

A bird is male on one side and female on the other

Male rose-breasted grosbeaks have some red-pink feathers while females’ are yellow and brown

A rose-breasted grosbeak has a pink breast spot and a pink “wing pit” and black feathers on its right wing — tell tale shades of males. But on its left side, the songbird displays yellow and brown plumage, hues typical of females.

Gynandromorphs are found in many species of birds, insects and crustaceans such as crabs and lobsters. This bird is likely the result of an unusual event when two sperm fertilize an egg that has two nuclei instead of one. The egg can then develop male sex chromosomes on one side and female sex chromosomes on the other, ultimately leading to a bird with a testis and other male characteristics on one half of its body and an ovary and other female qualities on the other half.

Unlike hermaphrodites, which also have genitals of both sexes, gynandromorphs are completely male on one side of the body and female on the other.

We don’t yet know if these birds behave more like males or females, or if they can reproduce

R.J. Agate et al. Neural, not gonadal, origin of brain sex differences in a gynandrom.... Proceedings of the National Academy of Sciences. Vol. 100, April 15, 2003, p. 4873. doi: 10.1073/pnas.0636925100.

RESEARCHERS AT POWDERMILL NATURE RESERVE OBSERVE RARE GYNANDROMORPH BIRD CONTAINING BOTH MALE AND FEMALE CHARACTERISTICS - Carnegie Museum of Natural History

https://carnegiemnh.org/press/researchers-at-powdermill-nature-rese...

Comment by Dr. Krishna Kumari Challa on October 10, 2020 at 5:29am

More Humans Are Growing an Extra Artery in Our Arms, Showing We're Still Evolving

Researchers have noticed an artery that temporarily runs down the centre of our forearms while we're still in the womb isn't vanishing as often as it used to.

That means there are more adults than ever running around with what amounts to be an extra channel of vascular tissue flowing under their wrist.

Since the 18th century, anatomists have been studying the prevalence of this artery in adults and our study shows it's clearly increasing.

The prevalence was around 10 percent in people born in the mid-1880s compared to 30 percent in those born in the late 20th century, so that's a significant increase in a fairly short period of time, when it comes to evolution.

Recently increased prevalence of the human median artery of the forearm: A microevolutionary change

The median artery has been considered as an embryonic structure, which normally regresses around the 8th week of gestation. However, various prevalences have been reported in adults since the 18th century. Furthermore, in a study by Henneberg and George (1995; Am J Phys Anthropol 96, 329–334), has suggested that increasing prevalence of the median artery during the 20th century was a ‘possible secular trend’. The present study, conducted nearly a quarter of a century later, is a continuation of that study. A total of 26 median arteries were found in 78 upper limbs obtained from Australians aged 51 to 101 years, who died in the period 2015–2016, a prevalence rate of 33.3%. Analysis of the literature showed that the presence of the median artery has been significantly increasing (p = .001) over time, from approximately 10% in people born in the mid‐1880s to approximately 30% by the end of the 20th century. The significance of the prevalence increased to a p value

https://onlinelibrary.wiley.com/doi/epdf/10.1111/joa.13224

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 6:10am

This ‘squidbot’ jets around and takes pics of coral and fish

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 6:08am

Millimetre-precision drug delivery to the brain

Researchers  have developed a method for concentrating and releasing drugs in the brain with pinpoint accuracy. This could make it possible in the future to deliver psychiatric and cancer drugs and other medications only to those regions of the brain where this is medically desirable.

In order to prevent a drug from acting on the entire brain and body, the new method involves special drug carriers that wrap the drugs in spherical lipid vesicles attached to gas-​containing ultrasound-​sensitive microbubbles. These are injected into the bloodstream, which transports them to the brain. Next, the scientists use focused ultrasound waves in a two-​stage process. Focused ultrasound is already employed in oncology to destroy cancer tissue at precisely defined points in the body. In the new invention, however, the scientists work with much lower energy levels, which do not damage the tissue.

Ozdas MS, Shah AS, Johnson PM, Patel N, Marks M, Yasar TB, Stalder U, Bigler L, von der Behrens W, Sirsi SR, Yanik MF: Non-​invasive molecularly-​specific millimeterresolution manipulation of brain circuits by ultrasound-​mediated aggregation and uncaging of drug carriers. Nature Communications, 1 October 2020, doi: 10.1038/s41467-​020-18059-7

https://ethz.ch/en/news-and-events/eth-news/news/2020/10/millimetre...

https://researchnews.cc/news/2923/Millimetre-precision-drug-deliver...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:47am

Stomach Acid & Heartburn Drugs Linked with COVID-19 Outcomes

While sick with COVID-19, President Trump is taking an antacid. Doctors have been exploring whether these medicines can treat SARS-CoV-2 infections, and the results are mixed.

The uncertainty of the COVID-19 pandemic has made our stomachs churn, and now, evidence suggests that intense heartburn may be linked with worse symptoms of the disease. Some drugs that neutralize stomach acid, such as famotidine, which President Donald Trump is taking, are associated with reduced severity, but others, such as Prilosec, correlate with higher infection rates and risk of death, at least in patients hospitalized with SARS-CoV-2 infections.

https://www.the-scientist.com/news-opinion/stomach-acid-heartburn-d...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:42am

Signals from distant stars connect optical atomic clocks across Earth for the first time

Using radio telescopes observing distant stars, scientists have connected optical atomic clocks on different continents.

 Marco Pizzocaro et al, Intercontinental comparison of optical atomic clocks through very long baseline interferometry, Nature Physics (2020). DOI: 10.1038/s41567-020-01038-6

In this new research, highly-energetic extragalactic radio sources replace satellites as the source of reference signals. The group of Sekido Mamoru at NICT designed two special radio telescopes, one deployed in Japan and the other in Italy, to realize the connection using the technique of Very Long Baseline Interferometry (VLBI). These telescopes are capable of observations over a large bandwidth, while antenna dishes of just 2.4 meter diameter keep them transportable.

https://phys.org/news/2020-10-distant-stars-optical-atomic-clocks.h...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:38am

Thinning forests no defence against fires

Having logging machines "thin" forest for fire reduction is largely ineffective, a new peer-reviewed, scientific study has found.

The study compared fire severity in unthinned versus thinned forest burned in the 2009 wildfires. It covered two forest types-mixed species forest and ash forest.

The scientific evidence showed that across almost every forest age and type, thinning made little difference. It actually increased the likelihood of a crown burn in older, mixed species forests, and slightly reduced the chance of crown burn in younger aged, mixed species forest.

The impact of thinning varied with forest type, the age of the forest and fire conditions.

--

Across most forest types and ages, thinning had little impact on forest fire severity, although it did worsen severity in mixed species forest aged 70 years plus and did reduce it in mixed species forest aged 20-40 years. Overall, the evidence indicates thinning forests does not reduce fire risk.

Chris Taylor et al. Does forest thinning reduce fire severity in Australian eucalypt forests?, Conservation Letters (2020). DOI: 10.1111/conl.12766

https://phys.org/news/2020-10-thinning-forests-defence.html?utm_sou...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:33am

**New model may explain rarity of certain malaria-blocking mutations

A new computational model suggests that certain mutations that block infection by the most dangerous species of malaria have not become widespread in people because of the parasite's effects on the immune system.

Several protective adaptations to malaria have spread widely among humans, such as the sickle-cell mutation. Laboratory experiments suggest that certain other mutations could be highly protective against the most dangerous human-infecting malaria species, Plasmodium falciparum. However, despite being otherwise benign, these mutations have not become widespread.

To help clarify why some protective mutations may remain rare, Penman and colleagues developed a computational model that simulates the epidemiology of malaria infection, as well the evolution of protective mutations. Importantly, the model also incorporates mechanisms of adaptive immunity, in which the immune system "learns" to recognize and attack specific pathogens, such as P. falciparum.

Analysis of the model's predictions suggests that if people rapidly gain adaptive immunity to the severe effects of P. falciparum malaria, mutations capable of blocking P. falciparum infection are unlikely to spread among the population. The fewer the number of infections it takes for people to become immune to the severe effects of malaria, the less likely it is that malaria infection-blocking mutaions will arise.

understanding how humans have adapted to malaria could help open up new avenues for treatment.

 Penman BS, Gandon S (2020) Adaptive immunity selects against malaria infection blocking mutations. PLoS Comput Biol 16(10): e1008181. doi.org/10.1371/journal.pcbi.1008181

https://phys.org/news/2020-10-rarity-malaria-blocking-mutations.htm...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:30am

Human spatial memory prioritizes high calorie foods

Humans more accurately recall the locations of high calorie than low calorie foods, according to a study . The findings suggest that human spatial memory, which allows people to remember where objects are in relation to each another, has evolved to prioritize the location of high calorie foods.

The findings indicate that human spatial memory is biased towards locating high calorie foods. This bias could have helped human ancestors to survive in environments with fluctuating food availability by enabling them to efficiently locate calorie-dense foods through foraging.

Human spatial memory implicitly prioritizes high-calorie foods, Scientific Reports (2020). DOI: 10.1038/s41598-020-72570-x , www.nature.com/articles/s41598-020-72570-x

https://medicalxpress.com/news/2020-10-human-spatial-memory-priorit...

Comment by Dr. Krishna Kumari Challa on October 9, 2020 at 5:20am

Ants adapt tool use to avoid drowning

Researchers have observed black imported fire ants using sand to draw liquid food out of containers, when faced with the risk of drowning. This is the first time this sophisticated tool use has been reported in animals.

Aiming Zhou et al, Ants adjust their tool use strategy in response to foraging risk, Functional Ecology (2020). DOI: 10.1111/1365-2435.13671

--

Nanoscale machines convert light into work

Researchers have developed a tiny new machine that converts laser light into work. These optically powered machines self-assemble and could be used for nanoscale manipulation of tiny cargo for applications such as nanofluidics and particle sorting.

The work addresses a long-standing goal in the nanoscience community to create self-assembling nanoscale machines that can perform work in conventional environments such as room temperature liquids.

The machines are based on a type of matter known as optical matter in which metal nanoparticles are held together by light rather than the chemical bonds that hold together the atoms that make up typical matter.

Both the energy for assembling the machine and the power to make it work come from light. Once the laser light is introduced to a solution containing nanoparticles, the entire process occurs on its own. Although the user does not need to actively control or direct the outcome, this could readily be done to tailor the machines for various applications.

In optical matter, a laser light field creates interactions between metal nanoparticles that are much smaller than the wavelength of light. These interactions cause the particles to self-assemble into ordered arrays. This is a similar principle to optical trapping, in which light is used to hold and manipulate particles, biological molecules and cells.

--

In the new work, the researchers created an optical matter machine that operates much like a mechanical machine based on interlocking gears. In such machines, when one gear is turned, a smaller interlocking gear will spin in the opposite direction. The optical matter machine uses circularly polarized light from a laser to create a nanoparticle array that acts like the larger gear by spinning in the optical field. This "optical matter gear" converts the circularly polarized light into orbital, or angular, momentum that influences a nearby probe particle to orbit the nanoparticle array (the gear) in the opposite direction.

--

In previous work, the researchers discovered that when optical matter is exposed to circularly polarized light, it rotates as a rigid body in the direction opposite the polarization rotation. In other words, when the incident light  rotates one way the optical matter array responds by spinning the other. This is a manifestation of "negative torque". The researchers speculated that a machine could be developed based on this new phenomenon.

John Parker et al, An Optical Matter Machine: Angular Momentum Conversion by Collective Modes in Optically Bound Nanoparticle Arrays, Optica (2020). DOI: 10.1364/OPTICA.396147

https://phys.org/news/2020-10-nanoscale-machines.html?utm_source=nw...

• ‹ Previous
• 1
• …
• 741
• 742
• 743
• 744
• 745
• …
• 1079
• Next ›
• Page