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What are the nuclear codes?

Live Science - Vie, 12/08/2022 - 10:43
The nuclear codes carried by the president at all times don't launch an attack directly, but they prove the president's authority to drop the big one.

Monkeys in Bali use stones as sex toys to fill their leisure time

New Scientist - Vie, 12/08/2022 - 09:36
Male and female macaques in a Balinese sanctuary commonly use stone tools to masturbate, possibly because they have more leisure time than wild primates

Interstellar meteorite may be awaiting discovery on the sea floor

New Scientist - Vie, 12/08/2022 - 08:31
A pair of astronomers say that classified US government sensors detected an interstellar meteor hitting Earth in 2014. Now they want to mount a $1.6 million expedition to find fragments of it on the sea floor

New Research Reveals the Circadian Clock Influences Cell Growth, Metabolism, and Tumor Progression

Slashdot - Science - Vie, 12/08/2022 - 08:00
An anonymous reader quotes a report from Phys.Org: In a new University of California, Irvine-led study, researchers define how the circadian clock influences cell growth, metabolism and tumor progression. Their research also reveals how disruption of the circadian clock impacts genome stability and mutations that can further drive critical tumor-promoting pathways in the intestine. In this study, researchers found that both genetic disruption and environmental disruption of the circadian clock contribute to the mutation of the adenomatous polyposis coli (APC) tumor suppressor, which is found in the vast majority of human colorectal cancers (CRC). APC point mutations, deletions, and loss of heterozygosity (LOH) events have been reported in approximately 80 percent of human CRC cases, and it is these mutations that drive the initiation of intestinal adenoma development. "As a society, we are exposed to several environmental factors that influence our biological clock, including night shift work, extended light exposure, changes in sleep/wake cycles and altered feeding behavior," said Selma Masri, Ph.D., assistant professor of biological chemistry at UCI School of Medicine. "Strikingly, we have seen an alarming increase in several young-onset cancers, including colorectal cancer. The underlying cause of this increased incidence of cancer in adults in their 20s and 30s remains undefined. However, based on our findings, we now believe that disruption of the circadian clock plays an important role." The study has been published in the journal Science Advances.

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Probiotics for vaginal health: Benefits, safety and risks

Live Science - Vie, 12/08/2022 - 07:00
Is it safe to use probiotics for vaginal health? Our experts weigh in on the potential benefits and risks

Mars astronauts would get unsafe radiation doses even with shielding

New Scientist - Vie, 12/08/2022 - 06:14
Simulations show that a 1000-day mission to Mars would expose astronauts to radiation doses above 1 sievert, even with metal shielding

Sweet dreams, spidey: Arachnids experience REM sleep, and may even dream

Live Science - Vie, 12/08/2022 - 06:00
Spiders likely sleep and dream like humans do.

Is Nazi gold real?

Live Science - Vie, 12/08/2022 - 05:00
Nazi soldiers looted numerous valuable items and tons of gold, but the chances of locating buried treasure are tiny.

Giant voids of nothingness may be flinging the universe apart

Live Science - Vie, 12/08/2022 - 04:00
Dark energy could be caused by pressure from giant voids of nothingness that may be flinging the universe apart.

DOE Digs Up Molten Salt Nuclear Reactor Tech, Los Alamos To Lead the Way Back

Slashdot - Science - Vie, 12/08/2022 - 02:00
After more than 50 years, molten salt nuclear reactors might be making a comeback. The US Department of Energy (DoE) has tapped Los Alamos National Laboratory (LANL) to lead a $9.25 million study into the structural properties and materials necessary to build them at scale. The Register reports: "The US needs projects like this one to advance nuclear technologies and help us achieve the Biden-Harris administration's goals of clean energy by 2035 and a net-zero economy by 2050," said Asmeret Asefaw Berhe, director of the office of science, in a statement. The study, conducted as part of the Scientific Discovery though Advanced Computing (SciDAC) program, seeks to gain a better understanding of the relationship between corrosion and irradiation effects at the atomic scale in metals exposed to molten salt reactors through simulation. This isn't the first time the DoE has explored this reactor tech. In the middle of last century, Oak Ridge National Laboratory (ORNL) took the lessons learned from the Aircraft Reactor experiment to build a functional nuclear aircraft power source and began construction of a molten salt test reactor. The experiments, conducted between 1957 and 1969, utilized a mixture of lithium, beryllium, zirconium, and uranium fluoride salts. Cooling was also achieved using a fluoride salt mixture, but it lacked the uranium and zirconium found in the fuel. The experiments proved promising, as molten salt reactors were generally smaller and considered safer compared to the pressurized water reactors still used today. But both proved too heavy for powered flight or materials design. Because cooling was achieved by circulating molten salt through a heat exchanger as opposed to water, the risk of a steam explosion is effectively nonexistent. However, as the Oak Ridge National Laboratory found during the Molten Salt Reactor Experiment, fluoride salts are incredibly corrosive and required hardened materials to safely contain them. "ORNL's Molten Salt Reactor Experiment utilized specialized materials fabricated from Hastelloy-N -- a nickel-molybdenum alloy developed by the lab with a high resistance to corrosion even at high temperatures," adds the reports. "The research program announced this week will revisit the material choices and examine a variety of metals using higher-performance compute resources to simulate how they'll perform at scale in these reactors."

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A New Study Overturns 100-Year-Old Understanding of Color Perception

Slashdot - Science - Jue, 11/08/2022 - 22:30
An anonymous reader quotes a report from Phys.Org: A new study corrects an important error in the 3D mathematical space developed by the Nobel Prize-winning physicist Erwin Schrodinger and others, and used by scientists and industry for more than 100 years to describe how your eye distinguishes one color from another. The research has the potential to boost scientific data visualizations, improve TVs and recalibrate the textile and paint industries. [...] "Our original idea was to develop algorithms to automatically improve color maps for data visualization, to make them easier to understand and interpret," [said Roxana Bujack, a computer scientist with a background in mathematics who creates scientific visualizations at Los Alamos National Laboratory and lead author of the paper]. So the team was surprised when they discovered they were the first to determine that the longstanding application of Riemannian geometry, which allows generalizing straight lines to curved surfaces, didn't work. To create industry standards, a precise mathematical model of perceived color space is needed. First attempts used Euclidean spaces -- the familiar geometry taught in many high schools; more advanced models used Riemannian geometry. The models plot red, green and blue in the 3D space. Those are the colors registered most strongly by light-detecting cones on our retinas, and -- not surprisingly -- the colors that blend to create all the images on your RGB computer screen. In the study, which blends psychology, biology and mathematics, Bujack and her colleagues discovered that using Riemannian geometry overestimates the perception of large color differences. That's because people perceive a big difference in color to be less than the sum you would get if you added up small differences in color that lie between two widely separated shades. Riemannian geometry cannot account for this effect. "We didn't expect this, and we don't know the exact geometry of this new color space yet," Bujack said. "We might be able to think of it normally but with an added dampening or weighing function that pulls long distances in, making them shorter. But we can't prove it yet." The findings appear in the journal Proceedings of the National Academy of Science.

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Covid-19 vaccines in pregnancy not linked to miscarriage or stillbirth

New Scientist - Jue, 11/08/2022 - 18:30
The risks of catching covid-19, or being vaccinated against it, during pregnancy have been debated throughout the pandemic, with research now overwhelmingly supporting that pregnant people get vaccinated

US CO2 shortage worsened by contaminated gas from an extinct volcano

New Scientist - Jue, 11/08/2022 - 17:39
An extinct volcano’s underground reservoir in Mississippi has supplied CO2 to US beverage makers and food processing companies for decades. But natural contamination has exacerbated an ongoing CO2 shortage

China Overtakes the US In Scientific Research Output

Slashdot - Science - Jue, 11/08/2022 - 17:02
An anonymous reader quotes a report from The Guardian: China has overtaken the US as the world leader in both scientific research output and "high impact" studies, according to a report published by Japan's science and technology ministry. The report, which was published by Japan's National Institute of Science and Technology Policy (NISTP) on Tuesday, found that China now publishes the highest number of scientific research papers yearly, followed by the US and Germany. The figures were based on yearly averages between 2018 and 2020, and drawn from data compiled by the analytics firm Clarivate. The Japanese NISTP report also found that Chinese research comprised 27.2% of the world's top 1% most frequently cited papers. The number of citations a research paper receives is a commonly used metric in academia. The more times a study is cited in subsequent papers by other researchers, the greater its "citation impact." The US accounted for 24.9% of the top 1% most highly cited research studies, while UK research was third at 5.5%. China published a yearly average of 407,181 scientific papers, pulling ahead of the US's 293,434 journal articles and accounting for 23.4% of the world's research output, the report found. China accounted for a high proportion of research into materials science, chemistry, engineering and mathematics, while US researchers were more prolific in research into clinical medicine, basic life sciences and physics. "China is one of the top countries in the world in terms of both the quantity and quality of scientific papers," Shinichi Kuroki of the Japan Science and Technology Agency told Nikkei Asia. "In order to become the true global leader, it will need to continue producing internationally recognized research."

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CDC Drops Quarantine, Distancing Recommendations For COVID-19

Slashdot - Science - Jue, 11/08/2022 - 16:42
The nation's top public health agency relaxed its COVID-19 guidelines Thursday, dropping the recommendation that Americans quarantine themselves if they come into close contact with an infected person. The Centers for Disease Control and Prevention also said people no longer need to stay at least 6 feet away from others. The Associated Press reports: The changes, which come more than 2 1/2 years after the start of the pandemic, are driven by a recognition that an estimated 95% of Americans 16 and older have acquired some level of immunity, either from being vaccinated or infected, agency officials said. "The current conditions of this pandemic are very different from those of the last two years," said the CDC's Greta Massetti, an author of the guidelines. Perhaps the biggest education-related change is the end of the recommendation that schools do routine daily testing, although that practice can be reinstated in certain situations during a surge in infections, officials said. The CDC also dropped a "test-to-stay" recommendation, which said students exposed to COVID-19 could regularly test -- instead of quarantining at home -- to keep attending school. With no quarantine recommendation anymore, the testing option disappeared too. Masks continue to be recommended only in areas where community transmission is deemed high, or if a person is considered at high risk of severe illness.

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Some Firefly Species Await a Night That Never Comes

Slashdot - Science - Jue, 11/08/2022 - 16:25
A study found that while some fireflies shrugged off light pollution, members of other species failed to mate even when males and females could find each other. From a report: As dusk deepens the shadow at the forest's edge, a tiny beacon lights up the gloom. Soon, the twilight is full of drifting lights, each winking a message in peculiar semaphore: "Male seeks female for brief union." This courtship plays out on summer nights the world over among beetles of the Lampyridae family, commonly known as fireflies. The darkness in which fireflies have always pursued their liaisons, however, has been breached by the glare of artificial lights. Humans' love affair with illumination has led to much of the Earth's habitable surfaces suffering light pollution at night. In recent years, scientists who study fireflies have heard from people who are worried that the insects may be in decline, said Avalon Owens, an entomologist at Tufts University. "There's this sense of doom. They seem to not be in places where they used to be," she said. So little is known about how fireflies live that it is hard to assess whether they are in danger -- and if so, why, said Dr. Owens. But in a study published Wednesday in the journal Royal Society Open Science, she and Sara Lewis, a professor of biology at Tufts University, shone some light on how fireflies respond to artificial illumination. Experiments in forests and fields as well as the lab showed that while some North American fireflies would mate with wild abandon, regardless of illumination, others did not complete a single successful mating under the glare of the lights. Fireflies seem to rely primarily on flashes of light to find each other, which means light pollution could threaten their ability to see mates. In the four common species the study examines, the females hide on the ground and observe as males wander the skies. When a female responds to a male's flashing with her own, the two enter into a dialogue that can end in a meeting, and eventually mating.

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Ignition confirmed in a nuclear fusion experiment for the first time

New Scientist - Jue, 11/08/2022 - 16:19
A 2021 experiment achieved the landmark milestone of nuclear fusion ignition, which data analysis has now confirmed – but attempts to recreate it over the last year haven’t been able to reach ignition again

The Search For an AC That Doesn't Destroy the Planet

Slashdot - Science - Jue, 11/08/2022 - 14:22
An anonymous reader shares a report: Technology to build cleaner, more efficient air conditioners does exist. Two major AC manufacturers, Daikin and Gree Electric Appliances, shared the top award at last year's Global Cooling Prize, an international competition focused on designing climate-friendly AC tech. Both companies created ACs with higher internal performance that used less environmentally damaging refrigerants; the new units could reduce their impact on the climate by five times. [...] Another strategy is to double down on heat pumps, which are air conditioners that also work in reverse, using vapor compression to absorb and move heat into a home, instead of releasing it outside. Heat pumps usually cost several thousand dollars, though the Inflation Reduction Act includes a proposal for a significant heat pump rebate, and President Joe Biden has invoked the Defense Production Act to ramp up production. Experts have argued installing heat pumps is critical to another important climate goal: transitioning away from fossil fuel-powered furnaces, which are an even bigger source of emissions than cooling. The holy grail of HVAC would be a heat pump that could provide both heating and cooling but isn't dependent on vapor compression. [...] Another challenge, though, is that heat pumps are not the easiest appliance to install, especially for renters, who don't necessarily have the money or ability to invest in bulky HVAC systems. To address this problem, a company called Gradient has designed a heat pump that easily slides over a windowsill -- it doesn't block light -- and currently uses a refrigerant called R32, which is supposed to have a (comparatively) low global warming potential. Gradient recently won a contract to install its units in New York City public housing.

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Losing parts of our voice box may have helped humans evolve to speak

New Scientist - Jue, 11/08/2022 - 14:00
Unlike people, 43 species of monkeys and apes are known to have so-called vocal membranes, which may prevent them from having precise voice control

Hovering robots could get more lift by 'treading water' in the air

New Scientist - Jue, 11/08/2022 - 13:58
Moving like an insect may not be the most efficient way for tiny flying robots to hover – they get more lift by taking advantage of vortices of air that form under their wings


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