Mexico detains more than 5,200 migrants in single day

A drone view shows migrants in a caravan bound to the northern border with the U.S., in Escuintla, Chiapas state, Mexico, December 3, 2024. MEXICO CITY, Dec 4 (Reuters) - Mexican authorities detained more than 5,200 migrants across the country on Tuesday, officials said on Wednesday, in a major sweep as the nation is under pressure from the incoming U.S. government to crack down on arrivals at the U.S.-Mexico border. U.S. President-elect Donald Trump has called on Mexico to ramp up efforts to stop both migrants and synthetic drugs such as fentanyl from coming into the U.S., threatening to slap tariffs on the southern trade partner. From Oct. 1 to Dec. 3, Mexican authorities have apprehended nearly 350,000 migrants, according to the Navy. Mexican President Claudia Sheinbaum said last week that a recent migrant caravan traveling through the south of the country would not make it north as migration authorities were "tending to" those remaining. Tuesday's detentions were carried out by the Army, National Guard and state police, the Navy said, in support of migration authorities. The armed forces have taken on increased responsibilities in public security as of late, particularly in the south, where migrants arrive on foot from Central America.

‘No movement at all’: Snowstorms in Ontario’s cottage country strand motorists, drop more than a metre of snow

This photo provided by the Ontario Provincial Police shows vehicles stranded on Highway 11. Communities in cottage country north of Toronto continued to dig out Sunday after multiple days of intense snowstorms stranded motorists on Highway 11 and left thousands in the dark. Hamilton resident Dan Vucic told the Star he has been stuck on the highway in Gravenhurst, Ont. — which has seen a whopping 140 centimetres of snow since Friday, according to Environment Canada — for over 24 hours. “OPP police on snowmobiles passed by and they said be ready for a long wait,” Vucic told the Star over the phone Sunday afternoon, before adding “there’s not much I can do now, just wait on the highway.” Vucic has a bed and plenty of food prepared in his truck and said, “I’ve been stuck before, I never leave unprepared.” “It’s probably about two and a half feet. There’s no movement at all,” Vucic said. He said he doesn’t think he’ll be out until Monday. Gravenhurst was one of the hardest hit communities from the multi-day “lake-effect snow squall event” that Environment Canada has been warning about since Friday, leading the town to declare a state of emergency. Mayor Heidi Lorenz says she has never seen this much snow in her 27 years as a resident. “The snow banks outside my home, mind you I’m not very tall, but they’re as tall as I am. In two days we got that much snow,” said Lorenz. Lorenz decided on the emergency declaration — the first time she’s done so as mayor — around 2 a.m. Sunday morning after realizing Highway 11 was not opening up anytime soon and many people were still stranded. It was unclear how many people were still stranded as of Sunday, though an OPP police spokesperson suggested some had been stuck overnight. Police and city officials have not reported any serious injuries due to the storm. People who requested help had been pulled from the highway by Sunday morning as work continued into the afternoon to tow the last abandoned cars, said Brookyln Harker, OPP Central Region’s media relations co-ordinator. Premier Doug Ford said the province was working closely with local authorities to help them respond to the storm. Ford said he was relieved no injuries or deaths had been reported. “As cleanup crews continue their work, the best thing people in the area can do is stay home and stay safe until power is restored and roads and highways have been safely opened again,” he said in a statement posted to social media. Highly recommended visit this source link to know more!

Researchers learn more about teen-age T. rex

Without a doubt, Tyrannosaurus rex is the most famous dinosaur in the world. The 40-foot-long predator with bone crushing teeth inside a five-foot long head are the stuff of legend. Now, a look within the bones of two mid-sized, immature T. rex allow scientists to learn about the tyrant king's terrible teens as well.

In the early 2000s, the fossil skeletons of two comparatively small T. rex were collected from Carter County, Montana, by Burpee Museum of Natural History in Rockford, Illinois. Nicknamed "Jane" and "Petey," the tyrannosaurs would have been slightly taller than a draft horse and twice as long.

The team led by Holly Woodward, Ph.D., from Oklahoma State University Center for Health Sciences studied Jane and Petey to better understand T. rex life history.

The study "Growing up Tyrannosaurus rex: histology refutes pygmy 'Nanotyrannus' and supports ontogenetic niche partitioning in juvenile Tyrannosaurus" appears in the peer-reviewed journal Science Advances.

Co-authors include Jack Horner, presidential fellow at Chapman University; Nathan Myhrvold, founder and CEO of Intellectual Ventures; Katie Tremaine, graduate student at Montana State University; Scott Williams, paleontology lab and field specialist at Museum of the Rockies; and Lindsay Zanno, division head of paleontology at the North Carolina Museum of Natural Sciences. Supplemental histological work was conducted at the Diane Gabriel Histology Labs at Museum of the Rockies/Montana State University.

"Historically, many museums would collect the biggest, most impressive fossils of a dinosaur species for display and ignore the others," said Woodward. "The problem is that those smaller fossils may be from younger animals. So, for a long while we've had large gaps in our understanding of how dinosaurs grew up, and T. rex is no exception."

The smaller size of Jane and Petey is what make them so incredibly important. Not only can scientists now study how the bones and proportions changed as T. rex matured, but they can also utilize paleohistology -- the study of fossil bone microstructure -- to learn about juvenile growth rates and ages. Woodward and her team removed thin slices from the leg bones of Jane and Petey and examined them at high magnification.

"To me, it's always amazing to find that if you have something like a huge fossilized dinosaur bone, it's fossilized on the microscopic level as well," Woodward said. "And by comparing these fossilized microstructures to similar features found in modern bone, we know they provide clues to metabolism, growth rate, and age."

The team determined that the small T. rex were growing as fast as modern-day warm-blooded animals such as mammals and birds. Woodward and her colleagues also found that by counting the annual rings within the bone, much like counting tree rings, Jane and Petey were teenaged T.rex when they died; 13 and 15 years old, respectively.

There had been speculation that the two small skeletons weren't T. rex at all, but a smaller pygmy relative Nanotyrannus. Study of the bones using histology led the researchers to the conclusion that the skeletons were juvenile T. rex and not a new pygmy species.

Instead, Woodward points out, because it took T. rex up to twenty years to reach adult size, the tyrant king probably underwent drastic changes as it matured. Juveniles such as Jane and Petey were fast, fleet footed, and had knife-like teeth for cutting, whereas adults were lumbering bone crushers. Not only that, but Woodward's team discovered that growing T. rex could do a neat trick: if its food source was scarce during a particular year, it just didn't grow as much. And if food was plentiful, it grew a lot.

"The spacing between annual growth rings record how much an individual grows from one year to the next. The spacing between the rings within Jane, Petey, and even older individuals is inconsistent -- some years the spacing is close together, and other years it's spread apart," said Woodward.

The research by Woodward and her team writes a new chapter in the early years of the world's most famous dinosaur, providing evidence that it assumed the crown of tyrant king long before it reached adult size.

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Materials provided by Oklahoma State University Center for Health Sciences. Note: Content may be edited for style and length.

Toward more efficient computing, with magnetic waves

Toward more efficient computing, with magnetic waves

MIT researchers have devised a novel circuit design that enables precise control of computing with magnetic waves -- with no electricity needed. The advance takes a step toward practical magnetic-based devices, which have the potential to compute far more efficiently than electronics.

Classical computers rely on massive amounts of electricity for computing and data storage, and generate a lot of wasted heat. In search of more efficient alternatives, researchers have started designing magnetic-based "spintronic" devices, which use relatively little electricity and generate practically no heat.

Spintronic devices leverage the "spin wave" -- a quantum property of electrons -- in magnetic materials with a lattice structure. This approach involves modulating the spin wave properties to produce some measurable output that can be correlated to computation. Until now, modulating spin waves has required injected electrical currents using bulky components that can cause signal noise and effectively negate any inherent performance gains.

The MIT researchers developed a circuit architecture that uses only a nanometer-wide domain wall in layered nanofilms of magnetic material to modulate a passing spin wave, without any extra components or electrical current. In turn, the spin wave can be tuned to control the location of the wall, as needed. This provides precise control of two changing spin wave states, which correspond to the 1s and 0s used in classical computing.

In the future, pairs of spin waves could be fed into the circuit through dual channels, modulated for different properties, and combined to generate some measurable quantum interference -- similar to how photon wave interference is used for quantum computing. Researchers hypothesize that such interference-based spintronic devices, like quantum computers, could execute highly complex tasks that conventional computers struggle with.

"People are beginning to look for computing beyond silicon. Wave computing is a promising alternative," says Luqiao Liu, a professor in the Department of Electrical Engineering and Computer Science (EECS) and principal investigator of the Spintronic Material and Device Group in the Research Laboratory of Electronics. "By using this narrow domain wall, we can modulate the spin wave and create these two separate states, without any real energy costs. We just rely on spin waves and intrinsic magnetic material."

Joining Liu on the paper are Jiahao Han, Pengxiang Zhang, and Justin T. Hou, three graduate students in the Spintronic Material and Device Group; and EECS postdoc Saima A. Siddiqui.

Flipping magnons

Spin waves are ripples of energy with small wavelengths. Chunks of the spin wave, which are essentially the collective spin of many electrons, are called magnons. While magnons are not true particles, like individual electrons, they can be measured similarly for computing applications.

In their work, the researchers utilized a customized "magnetic domain wall," a nanometer-sized barrier between two neighboring magnetic structures. They layered a pattern of cobalt/nickel nanofilms -- each a few atoms thick -- with certain desirable magnetic properties that can handle a high volume of spin waves. Then they placed the wall in the middle of a magnetic material with a special lattice structure, and incorporated the system into a circuit.

On one side of the circuit, the researchers excited constant spin waves in the material. As the wave passes through the wall, its magnons immediately spin in the opposite direction: Magnons in the first region spin north, while those in the second region -- past the wall -- spin south. This causes the dramatic shift in the wave's phase (angle) and slight decrease in magnitude (power).

In experiments, the researchers placed a separate antenna on the opposite side of the circuit, that detects and transmits an output signal. Results indicated that, at its output state, the phase of the input wave flipped 180 degrees. The wave's magnitude -- measured from highest to lowest peak -- had also decreased by a significant amount.

Adding some torque

Then, the researchers discovered a mutual interaction between spin wave and domain wall that enabled them to efficiently toggle between two states. Without the domain wall, the circuit would be uniformly magnetized; with the domain wall, the circuit has a split, modulated wave.

By controlling the spin wave, they found they could control the position of the domain wall. This relies on a phenomenon called, "spin-transfer torque," which is when spinning electrons essentially jolt a magnetic material to flip its magnetic orientation.

In the researchers' work, they boosted the power of injected spin waves to induce a certain spin of the magnons. This actually draws the wall toward the boosted wave source. In doing so, the wall gets jammed under the antenna -- effectively making it unable to modulate waves and ensuring uniform magnetization in this state.

Using a special magnetic microscope, they showed that this method causes a micrometer-size shift in the wall, which is enough to position it anywhere along the material block. Notably, the mechanism of magnon spin-transfer torque was proposed, but not demonstrated, a few years ago. "There was good reason to think this would happen," Liu says. "But our experiments prove what will actually occur under these conditions."

The whole circuit is like a water pipe, Liu says. The valve (domain wall) controls how the water (spin wave) flows through the pipe (material). "But you can also imagine making water pressure so high, it breaks the valve off and pushes it downstream," Liu says. "If we apply a strong enough spin wave, we can move the position of domain wall -- except it moves slightly upstream, not downstream."

Such innovations could enable practical wave-based computing for specific tasks, such as the signal-processing technique, called "fast Fourier transform." Next, the researchers hope to build a working wave circuit that can execute basic computations. Among other things, they have to optimize materials, reduce potential signal noise, and further study how fast they can switch between states by moving around the domain wall. "That's next on our to-do list," Liu says.

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Materials provided by Massachusetts Institute of Technology. Original written by Rob Matheson. Note: Content may be edited for style and length.

Babies in the womb may see more than we thought

Illustration of fetus inside womb

By the second trimester, long before a baby's eyes can see images, they can detect light.

But the light-sensitive cells in the developing retina -- the thin sheet of brain-like tissue at the back of the eye -- were thought to be simple on-off switches, presumably there to set up the 24-hour, day-night rhythms parents hope their baby will follow.

University of California, Berkeley, scientists have now found evidence that these simple cells actually talk to one another as part of an interconnected network that gives the retina more light sensitivity than once thought, and that may enhance the influence of light on behavior and brain development in unsuspected ways.

In the developing eye, perhaps 3% of ganglion cells -- the cells in the retina that send messages through the optic nerve into the brain -- are sensitive to light and, to date, researchers have found about six different subtypes that communicate with various places in the brain. Some talk to the suprachiasmatic nucleus to tune our internal clock to the day-night cycle. Others send signals to the area that makes our pupils constrict in bright light.

But others connect to surprising areas: the perihabenula, which regulates mood, and the amygdala, which deals with emotions.

In mice and monkeys, recent evidence suggests that these ganglion cells also talk with one another through electrical connections called gap junctions, implying much more complexity in immature rodent and primate eyes than imagined.

"Given the variety of these ganglion cells and that they project to many different parts of the brain, it makes me wonder whether they play a role in how the retina connects up to the brain," said Marla Feller, a UC Berkeley professor of molecular and cell biology and senior author of a paper that appeared this month in the journal Current Biology. "Maybe not for visual circuits, but for non-vision behaviors. Not only the pupillary light reflex and circadian rhythms, but possibly explaining problems like light-induced migraines, or why light therapy works for depression."

Parallel systems in developing retina

The cells, called intrinsically photosensitive retinal ganglion cells (ipRGCs), were discovered only 10 years ago, surprising those like Feller who had been studying the developing retina for nearly 20 years. She played a major role, along with her mentor, Carla Shatz of Stanford University, in showing that spontaneous electrical activity in the eye during development -- so-called retinal waves -- is critical for setting up the correct brain networks to process images later on.

Hence her interest in the ipRGCs that seemed to function in parallel with spontaneous retinal waves in the developing retina.

"We thought they (mouse pups and the human fetus) were blind at this point in development," said Feller, the Paul Licht Distinguished Professor in Biological Sciences and a member of UC Berkeley's Helen Wills Neuroscience Institute. "We thought that the ganglion cells were there in the developing eye, that they are connected to the brain, but that they were not really connected to much of the rest of the retina, at that point. Now, it turns out they are connected to each other, which was a surprising thing."

UC Berkeley graduate student Franklin Caval-Holme combined two-photon calcium imaging, whole-cell electrical recording, pharmacology and anatomical techniques to show that the six types of ipRGCs in the newborn mouse retina link up electrically, via gap junctions, to form a retinal network that the researchers found not only detects light, but responds to the intensity of the light, which can vary nearly a billionfold.

Gap junction circuits were critical for light sensitivity in some ipRGC subtypes, but not others, providing a potential avenue to determine which ipRGC subtypes provide the signal for specific non-visual behaviors that light evokes.

"Aversion to light, which pups develop very early, is intensity-dependent," suggesting that these neural circuits could be involved in light-aversion behavior, Caval-Holme said. "We don't know which of these ipRGC subtypes in the neonatal retina actually contributes to the behavior, so it will be very interesting to see what role all these different subtypes have."

The researchers also found evidence that the circuit tunes itself in a way that could adapt to the intensity of light, which probably has an important role in development, Feller said.

"In the past, people demonstrated that these light-sensitive cells are important for things like the development of the blood vessels in the retina and light entrainment of circadian rhythms, but those were kind of a light on/light off response, where you need some light or no light," she said. "This seems to argue that they are actually trying to code for many different intensities of light, encoding much more information than people had previously thought."

The research was supported by the National Institutes of Health (NIH F31EY028022-03, RO1EY019498, RO1EY013528, P30EY003176).

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Materials provided by University of California - Berkeley. Original written by Robert Sanders. Note: Content may be edited for style and length.

Opioid prescription doses are increasingly being tapered, often more rapidly than recommended

Opiods

Stigma and safety fears have made daily dose tapering of opioid prescriptions more common. New research from UC Davis Health physicians, however, shows tapering can occur at rates as much as six times higher than recommended, putting patients at risk of withdrawal, uncontrolled pain or mental health crises.

The study -- "Trends and Rapidity of Dose Tapering Among Patients Prescribed Long-term Opioid Therapy, 2008-2017" -- is published in JAMA Network Open. The results also will be presented at the Nov. 16-19 North American Primary Care Research Group meeting in Toronto.

"Tapering plans should be based on the needs and histories of each patient and adjusted as needed to avoid adverse outcomes," said study author Alicia Agnoli, assistant professor of family and community medicine. "Unfortunately, a lot of tapering occurs due to policy pressures and a rush to get doses below a specific and sometimes arbitrary threshold. That approach can be detrimental in the long run."

In 2016, the U.S. Centers for Disease Control and Prevention (CDC) recommended dose tapering, or a slow reduction in prescription opioid doses over time, if the risks of continuing opioids outweigh the benefits. That point in time is usually when a patient is taking 90 morphine milligram equivalents -- or MMEs -- each day, and that dose is no longer reducing pain or improving daily functions. The CDC advises a slow decrease of 10% MMEs per month.

The study team set out to examine trends in opioid dose tapering and if tapering rates were consistent with CDC recommendations.

"We wanted to understand how often opioid dose tapering happens, how rapidly patients' doses were being reduced when tapering, and which patients were more likely to have doses tapered," said lead author Joshua Fenton, professor of family and community medicine.

Tapering faster than recommended

Fenton and Agnoli evaluated medical and pharmacy claims and enrollment records for more than 100,000 commercial insurance and Medicare Advantage enrollees, representing a diverse mixture of ages, races, ethnicities and locations across the U.S. They focused on individuals whose opioid doses were stable for at least a year and identified tapering patients as those with a 15% or more reduction in daily MMEs during a seven-month follow-up period.

They found that dose tapering became more common throughout the study period of 2008-2017, with the biggest jump following the CDC's 2016 prescribing guidelines. Tapering increased from 10.5% to 13.7% from 2008 to 2015, and from 16.2% to 22.4% from 2016 to 2017. Tapering was much more common in patients prescribed higher opioid dosages.

They also found that the rate of dose reduction often was well beyond the CDC's recommendation of 10% per month. The average reduction overall was 27.6% per month. Nearly 20% of patients tapered at a rate of 40% per month, and 5% tapered at a rate faster than 60% per month.

The 2016 policy could have been misinterpreted, leading many prescribers and health systems to insist on faster-than-recommended tapering, according to Agnoli.

"There is definitely a lot of pressure to reduce opioid use among patients, but there also is a need for more training and guidance for prescribers on how to help them safely do so," Agnoli said.

Women and tapering

Fenton and Agnoli also identified patient variables associated with tapering and uncovered an interesting difference in tapering rates based on sex.

While men have much higher rates of opioid use disorder and adverse outcomes related to opioids, women were more likely than men to have their opioid doses tapered.

"We think this has a lot to do with the gender dynamics of pain management and the physician-patient relationship," Agnoli said. "How women experience pain and discuss pain with their physicians is perhaps very different than men. There also could be some sex bias in terms of the patients that physicians choose to initiate conversations with about dose reduction."

Minimizing tapering risks

The researchers hope to build on this work to inform best practices for safe decision-making around dose reduction for all patients prescribed opioids.

"Ultimately, we want to clarify the effects of tapering on patients and how to help them taper to maximize benefits and minimize risks," Fenton said. "We expect this line of research will have important implications for how physicians manage and monitor patients who are undergoing opioid tapering."

Collaborators on this research were Guibo Xing, Daniel Tancredi, Anthony Jerant and Elizabeth Magnan of UC Davis Health, and Lillian Hang and Aylin Altan of OptumLabs in Minneapolis.

Their study was supported by UC Davis Health and OptumLabs and is available online.

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Materials provided by University of California - Davis Health. Note: Content may be edited for style and length.