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Image of Milky Way’s huge black hole captured – Hurriyet Daily News

WASHINGTON

Image of Milky Way’s huge black hole captured

The world’s first image of the chaotic supermassive black hole at the center of our Milky Way galaxy doesn’t portray a voracious cosmic destroyer but what astronomers on May 12 called a “gentle giant” on a near-starvation diet.

Astronomers believe nearly all galaxies, including our own, have these giant black holes at their bustling and crowded center, where light and matter cannot escape, making it extremely hard to get images of them. Light gets bent and twisted around by gravity as it gets sucked into the abyss along with superheated gas and dust.

The colorized image is from an international consortium behind the Event Horizon Telescope, a collection of eight synchronized radio telescopes around the world. Getting a good image was a challenge; previous efforts found the black hole too jumpy.

“It burbled and gurgled as we looked at it,” the University of Arizona’s Turkish astrophysicist Feryal Özel said.
She described it as a “gentle giant” while announcing the breakthrough along with other astronomers involved in the project. The picture also confirms Albert Einstein’s general theory of relativity: The black hole is precisely the size that Einstein’s equations dictate. It is about the size of the orbit of Mercury around our sun.
Black holes gobble up galactic material but Özel said this one is “eating very little.” It’s the equivalent to a person eating a single grain of rice over millions of years, another astronomer said.

“Pictures of black holes are the hardest thing to think about,” said astronomer Andrea Ghez of the University of California, Los Angeles. She wasn’t part of the telescope team bu t earned a Nobel Prize for the discovery of the Milky Way’s black hole in the 1990s.
She said the image of “my baby” is exactly how it should be an eerie-looking orange-red ring with utter blackness in the middle.

Scientists had expected the Milky Way’s black hole to be more violent, especially since the only other image from another galaxy shows a far bigger and more active black hole.
“It is the cowardly lion of black holes,” said project scientist Geoffrey C. Bower of Taiwan’s Academia Sinica Institute of Astronomy and Astrophysics.
Because the black hole “is on a starvation diet” so little material is falling into the center, and that allows astronomers to gaze deeper, Bower said.

The Milky Way black hole is called Sagittarius A (with an asterisk denoting star). It’s near the border of Sagittarius and Scorpius constellations and is 4 million times more massive than our sun. Bower said it is probably more typical of what’s at the center of most galaxies, “just sitting there doing very little.”
It is incredibly hot, trillions of degrees, zel said.

The same telescope group released the first black hole image in 2019. The picture was from a galaxy 53 million light-years away that is 1,500 times bigger than the one in our galaxy. The Milky Way black hole is much closer, about 27,000 light-years away. A light year is 5.9 trillion miles (9.5 trillion kilometers).
To get the picture, the eight telescopes had to coordinate so closely “in a process similar to everyone shaking hands with everyone else in the room,” said astronomer Vincent Fish of the Massachusetts Institute of Technology.
Astronomers worked with data collected in 2017 to get the new images. The next step is a movie of one of those two black holes, maybe both, Fish said.

The project cost nearly $60 million with $28 million coming from the U.S. National Science Foundation.
Even though it is quieter than expected, the center of the Milky Way is an important place to study, Ghez said.
It’s “like an urban downtown, everything is more extreme. It’s crowded. Things move fast,” Ghez said in an interview. “We live out in the suburbs (in a spiral arm of the galaxy). Things are calm out here.”

Space,

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As monkeypox panic spreads, doctors in Africa see a double standard – The Washington Post

DAKAR, Senegal — In a part of Nigeria that has dealt with monkeypox outbreaks for years, one doctor saw the photos circulating in Western media this week and chuckled.

“Those are the very severe cases,” said Oyewale Tomori, a virologist in the nation’s southwest. “Like, ‘Ahh! This is monkeypox!’ ”

The virus — discovered five decades ago in the Democratic Republic of Congo — causes mild illness in most people, he said, along with blisters that usually clear up in weeks. It’s much less transmissible than the coronavirus and much less deadly than Ebola. There’s already an effective vaccine.

What bothers infectious-disease experts across the continent is the double standard that has emerged since monkeypox grabbed the world’s attention: Few seemed to care, or even notice, until people in the West started getting sick.

In the past two weeks, cases of the animal-borne virus typically found in West and Central Africa have popped up in the United States, Canada, Australia, Israel and a growing number of European countries. There have been at least 92 confirmed infections and no deaths. Belgium has imposed a 21-day quarantine. President Biden assured Americans that the United States has enough vaccine stocks to address the threat.

Yet global alarm bells didn’t sound as several African nations battled outbreaks in recent months. The graphic images blazing across social media — some of the same ones used to illustrate monkeypox since the 1970s — rarely feature White patients.

“These cases are recorded in Europe,” Tomori said. “Why are you using a picture of an African? Those are your pox.”

The World Health Organization has not yet verified the origin of the outbreak, though one WHO adviser told the Associated Press that the cases could be linked to raves in Spain and Belgium. Monkeypox usually spreads by close contact, including sexual activity.

Health officials suspect the virus has been traveling undetected in nonendemic nations for some time — potentially as far back as 2018. Early tests suggest cases stem from the West African strain, which the WHO said has a fatality rate of about 1 percent.

Before monkeypox struck the West this year, the WHO said Nigeria, Cameroon and the Central African Republic all recorded small case numbers. But contact tracing is limited, said Yap Boum, a Cameroonian epidemiologist. Infections tend to arise in remote, forested areas, where people encounter wildlife that carry monkeypox, such as primates and rodents.

“Maybe now that it’s happening over there, the problem will get more attention,” Boum said, “and we will gain access to more vaccines, more treatments — all the things we did not have the money for.”

The Democratic Republic of Congo has been battling the world’s largest outbreak by far: at least 1,238 cases and 57 deaths since January. The strain found there is also much more deadly, with a fatality rate as high as 10 percent. Many deaths are preventable, doctors said, but treatment can be hard to find in areas with underfunded hospitals.

“It can be devastating in the same way as covid-19,” said Health Minister Jean Jacques Mbungani. But the country’s monkeypox preparations lost steam during the pandemic. The nation needs more tests, more inoculations, more medical workers tracing cases and caring for the ill.

“The response is not effective,” Mbungani said, “and remains lethargic due to the scarcity of resources.”

As monkeypox cases rise in Europe and other parts of the globe, health authorities are expressing concern about the unusual uptick. (Video: Alexa Juliana Ard, Meryl Kornfield/The Washington Post)

The European Center for Disease Prevention and Control said Monday that the bulk of documented cases have been mild. Young children, pregnant women and people with weakened immune systems face a heightened risk.

One of Nigeria’s top genomic sequencing experts, Christian Happi, is inviting his counterparts to come study how his country has managed monkeypox.

“It’s not that scary here,” he said. “People are used to it. Come learn from our public health authorities. Come see how we contain it.”

The global enthusiasm to combat the virus should have arrived sooner, he said. Maybe it could have been eradicated by now.

“Paying attention to disease wherever it happens benefits everyone,” he said. “As the pandemic has shown us, we are all in this together.”

Ombour reported from Nairobi.

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Mothers of twins are not more fertile, just lucky – Science Daily

Are women who have twins more fertile? While previous studies concluded they are, a detailed analysis of more than 100,000 births from pre-industrial Europe by an international team of scientists shows they are not. The results of the study are now published in the scientific journal Nature Communications.

In humans, twinning usually occurs in about 1-3% of all births. Twinning is found in all populations despite being associated with a much higher risk of natal and postnatal health issues for both the mother and her children than single pregnancies. Given these risks, it seems that natural selection has prevented twinning from becoming more common during evolution. But why then has evolution by natural selection not prevented twinning altogether?

One common explanation has been that survival risks brought by twinning are partly hidden from natural selection because twinning comes with higher fertility. The idea is that women who are more fertile than average are also more likely to release more than one egg when they ovulate — making twinning a marker of high fertility. Many studies analysed demographic data and obtained results consistent with this view.

However, this new study shows that the former analyses have been flawed. “Previous studies are problematic because they cannot tell us whether mothers with twins give birth more often because they are especially fertile, or because giving birth more often increases the chance that one of these births is to twins,” explains principal investigator Alexandre Courtiol from the Leibniz Institute for Zoo and Wildlife Research in Germany.

The new results show that twinners are not unusually fertile. Previous science had mixed up cause and effect. “If a mother gives birth more often, it is more likely that one of these births is to twins — just like you are more likely to win if you buy more lottery tickets, or to be in a car accident if you drive a lot,” adds first author Ian Rickard from Durham University, UK. When the “lottery ticket effect” is taken into account, the authors found that mothers more likely to have twins actually gave birth less often — a result that contradicts previous findings.

To re-examine the relationship between twinning and fertility, the international team of 14 scientists combined large datasets of birth outcomes from several parts of pre-industrial Europe (today’s Finland, Sweden, Norway, Germany and Switzerland). “All these data originate from old parish records that have been meticulously digitised and transcribed,” explains co-author Virpi Lummaa from University of Turku, Finland. “To avoid the statistical trap that plagued former studies, we also had to deploy efficient and carefully calibrated statistical procedures,” adds co-author François Rousset from the Institut des Sciences de l’Evolution in Montpellier, France.

Figuring out what shapes the relationship between twinning and fertility is not only a question of academic interest but also a matter of public health. Indeed, biomedical studies looking for ways to improve female fertility have compared mothers with and without twins. However, co-author Erik Postma from the University of Exeter in the UK points out that, “such study designs ignore the multitude of factors influencing how often a woman gives birth, which will mask any genuine differences in physiology between mothers with and without twins.” In short, comparing groups of mothers with twins to groups of mothers without may hide the effects of twinning and fertility genes where they exist, or create the illusion of these if they do not exist.

“There is still much we do not understand about twinning, but our study suggests that twinning has not been eliminated by natural selection for two reasons. First, twinning is a consequence of double ovulation, which compensates for reproductive ageing and benefits all but the youngest of mothers. Second, when the risk of early mortality of twins is not too high, twinning is associated with larger family sizes although women with twins give birth less often. This is because twin births bring two offspring rather than one,” concludes Courtiol.

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Pull for pull – new method for the mechanical tensile testing of micro and nanofibers – Nanowerk

May 24, 2022

(Nanowerk News) Testing the stiffness or tensile strength of fibres in the nano to micro range experimentally, is often very time-consuming. The samples in most cases have to be affixed using adhesive on both ends. Not only curing of the adhesive takes time, but also the sensor to which the fibre is glued cannot be reused. Researchers from TU Wien, Mathis Nalbach, Philipp Thurner and Georg Schitter, have developed a test system that overcomes these obstacles. The functional principle is as follows: A magnetic microshpere attached to the nanofibre can be picked up with magnetic tweezers. This allows the sphere to be inserted into the fork attached to a force sensor and thereby coupled to the sensor. Since the magnetic sphere can also be removed from the fork using the magnetic tweezers, another nanofibre can be picked up immediately. This significantly increases the sample throughput. The researchers recently presented the patent-pending “NanoTens” tensile tester in the journal Review of Scientific Instruments (“Instrument for tensile testing of individual collagen fibrils with facile sample coupling and uncoupling”). Scheme of the nano-tensile testing setup Scheme of the nano-tensile testing setup – a nanofibre (here a collagen fibril) equipped with a magnetic microsphere is inserted into the microgripper via magnetic tweezers. Through controlled movement of the force sensor, force-distance curves can be recorded. After the test, the sample can easily be removed and a new one can be connected. (Image: TU Vienna)

Adapted to the real conditions

While the atomic force microscope can be used to examine the mechanical properties of a fibre by means of a nano-penetration test, the NanoTens enables material testing for fibres under the more relevant, tensile load. Philipp Thurner from the Biomechanics research department explains the working principle as follows: “You can imagine the device like a microscopic forklift. The magnetic ball, which is glued to the fibre, is inserted into the fork. By moving the fork up or down, the fibre can now be tested under tensile load. This type of load is particularly relevant for biological fibres such as collagen fibrils. Physiologically, these are mainly loaded under tension, and therefore their mechanical properties are particularly relevant under precisely this load.” The biomechanists Nalbach and Thurner mostly examine natural fibres such as collagen. Since their mechanical properties depend strongly on external conditions, it is important to also take these into account in tensile testing. “We succeed in this because tensile tests can be carried out in different media with the NanoTens. A dry collagen fibre, for example, is much more brittle and stiff than a moist or fully hydrated one. Its diameter also decreases significantly when it is dried out,” says Mathis Nalbach, first author of the study.

Quality and quantity increase

With their method, the researchers not only succeed in simulating physiological conditions, but the results generated with NanoTens also gain in validity. This is because a large number of measurements are needed to obtain meaningful results on biological materials such as collagen fibrils. “Conventional methods allow us to examine only one or two samples per week. This makes it virtually impossible to conduct statistically meaningful studies,” describes Nalbach the problem. Philipp Thurner adds: “The new method allows the fibres to be connected and disconnected quickly. As a result – and because the sensor is reused – we can not only increase the number of tensile tests to up to 50 measurements per week, but also the precision of the measurement.” The tensile tests can – depending on the choice – be carried out over a wide force range and also force-controlled via a control system. This is important because tensile test methods normally assume that the material has linear elastic properties. However, this is not the case with biological tissues, such as collagen fibrils: they are viscoelastic. Force-controlled tensile testing enables the investigation of this very viscoelasticity.

From the invention to the product

NanoTens has already been internationally patented by the TU Wien. The feasibility of the method has also been proven (TRL 6), as can be read in the study by Nalbach et al. “The next step would be to join forces with industrial partners. We hope to find a licensee with the help of the research and transfer support. We are interested in cooperating with industry on this topic,” says Mathis Nalbach. NanoTens is designed in such a way that it can generally be integrated into any indentation measuring device or atomic force microscope. In addition to materials science, tensile testing is also used – among others – in the life sciences, semiconductor technology and electronics.

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