By Samiha Khanna

A quick eye exam might one day allow eye doctors to check up on both your eyeglasses prescription and your brain health.

A study of more than 200 people at the Duke Eye Center published March 11 in the journal Ophthalmology Retina suggests the loss of blood vessels in the retina could signal Alzheimer’s disease. Authors of the study include the Neurology Department’s James Burke, MD, PhD, and Cynthia Dunn, PA-C.

In people with healthy brains, microscopic blood vessels form a dense web at the back of the eye inside the retina, as seen in 133 participants in a control group.

In the eyes of 39 people with Alzheimer’s disease, that web was less dense and even sparse in places. The differences in density were statistically significant after researchers controlled for factors including age, sex, and level of education, said Duke ophthalmologist and retinal surgeon Sharon Fekrat, MD, the study’s senior author.

“We’re measuring blood vessels that can’t be seen during a regular eye exam and we’re doing that with relatively new noninvasive technology that takes high-resolution images of very small blood vessels within the retina in just a few minutes,” she said. “It’s possible that these changes in blood vessel density in the retina could mirror what’s going on in the tiny blood vessels in the brain, perhaps before we are able to detect any changes in cognition.”

The study found differences in the retinas of those with Alzheimer’s disease when compared to healthy people and to those with mild cognitive impairment, often a precursor to Alzheimer’s disease.

With nearly 6 million Americans living with Alzheimer’s disease and no viable treatments or noninvasive tools for early diagnosis, its burden on families and the economy is heavy. Scientists at Duke Eye Center and beyond have studied other changes in the retina that could signal trouble upstream in the brain, such as thinning of some of the retinal nerve layers.

“We know that there are changes that occur in the brain in the small blood vessels in people with Alzheimer’s disease, and because the retina is an extension of the brain, we wanted to investigate whether these changes could be detected in the retina using a new technology that is less invasive and easy to obtain,” said Dilraj S. Grewal, M.D., a Duke ophthalmologist and retinal surgeon and a lead author on the study. The Duke study used a noninvasive technology called optical coherence tomography angiography (OCTA). OCTA machines use light waves that reveal blood flow in every layer of the retina.

An OCTA scan could even reveal changes in tiny capillaries — most less than half the width of a human hair — before blood vessel changes show up on a brain scan such as an MRI or cerebral angiogram, which highlight only larger blood vessels. Such techniques to study the brain are invasive and costly.

“Ultimately, the goal would be to use this technology to detect Alzheimer’s early, before symptoms of memory loss are evident, and be able to monitor these changes over time in participants of clinical trials studying new Alzheimer’s treatments,” Fekrat said.

In addition to Fekrat and Grewal, study authors include Stephen P. Yoon, Atalie C. Thompson, Bryce W. Polascik, Cynthia Dunn and James R. Burke.

The research was supported by National Institutes of Health (P30EY005722), the 2018 Unrestricted Grant from Research to Prevent Blindness, and the Karen L. Wrenn Alzheimer’s Disease Award.

https://neurology.duke.edu/about/news/could-eye-doctor-diagnose-alzheimer%E2%80%99s-you-have-symptoms

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Scientists have discovered the first case of male bees babysitting, and it turns out that these males often aren’t biological bee dads but hopeful stepdads of the youngsters.

Females of a small bluish-black Mediterranean bee (Ceratina nigrolabiata) dig out the pith of plant stems to make a nest, where a mom lays her eggs. Unlike honeybees, these are solitary bees with no colony of daughter-workers. Without that help, the mom herself must collect nectar and pollen to feed the young. But these are no latchkey larvae.

In 78 nests that researchers watched for 90 minutes, an adult male bee stayed in the nest’s entrance, rump outward, while the mom was out foraging. A male rear blocked a menacing ant that researchers put at the entrance in 41 attempted attacks. And in more than half of these attempted invasions, males pushed the ant out of the nest, says behavioral ecologist Michael Mikát of Charles University in Prague.

When mom buzzes back with food, she scratches against the male’s rump, and he moves to allow her into the nest. Then he goes back to being a dad door, or rather, a stepdad door. In 265 nests sampled, only 29 percent of the babysitting males had fathered even one offspring that they were guarding, Mikát and colleagues report the week of March 11 in the Proceedings of the National Academy of Sciences.

This male behavior isn’t some bizarre selflessness. The longer a male hangs around a female and her nest, the more likely he is to sire a youngster, Mikát found. (It’s a competition with other males for daughters. An unfertilized bee egg will grow into a male, but it takes sperm to create a female.)

Unlike honeybees, female C. nigrolabiata bees can mate at multiple points during their lives. So a male hanging around while a female is building her nest and laying eggs can still end up with one or more daughters in that nest. In terms of evolution, care for the offspring arises as a “side effect” of males looking to mate with a female while guarding her against rivals, Mikát says.

Even so, in the wild, males rarely stay with the same female for the entire time a nest develops.

Some closely related bee species also mate at various times throughout their lives, so Mikát suggests that this part of the lifestyle evolved first. That early step could have allowed the C. nigrolabiata bees to develop their simple form of biparental care, he says.

This babysitting report is a first for bees, says animal behaviorist Stephen Trumbo of the University of Connecticut in Waterbury who wasn’t involved in the research. But other insects have evolved two-parent care, he says. Some small pine beetles, for example, drill a hole in a tree, where a male and female grow fungal food and raise young. Like the bee nest, the farmstead has just one entrance, and Trumbo wonders if even an elaborate nuclear family like that could have started as happenstance babysitting of hopeful males.

https://www.sciencenews.org/article/first-male-bees-spotted-babysitting-are-mostly-stepdads

BY ARIS FOLLEY

A Texas man is planning to spend his retirement years at Holiday Inns nationwide instead of moving into a nursing home, in an effort to cut costs, ABC affiliate WSET reported. Terry Robinson of Spring, Texas, listed his reasons for spending his golden years as a customer of the hotel chain in a viral post on Facebook earlier this month.

While the average cost of a nursing home can amount to $188.00 per day, Robinson wrote in the post that reservations at the Holiday Inn cost $59.23 per night with a “combined long term stay discount and senior discount.”

“Breakfast is included and some have happy hours in the afternoon,” Robinson wrote. “That leaves $128.77 a day for lunch and dinner in any restaurant we want, or room service, laundry, gratuities and special TV movies. Plus, they provide a spa, swimming pool, a workout room, a lounge and washer-dryer, etc.”

“Most have free toothpaste and razors, and all have free shampoo and soap,” he went on to write, adding that “$5 worth of tips a day and you’ll have the entire staff scrambling to help you.”

“They treat you like a customer, not a patient,” he said.

Robinson added that the staff will also “call an ambulance … or the undertaker” if anything bad happens. Robinson also said that he would be able to travel wherever he wants with the retirement plan, as the Holiday Inn has more than 1,100 locations accords the world, according to USA Today. As for family visits, Robinson wrote that “they will always be glad to find you, and probably check in for a few days mini-vacation.”

“The grand-kids can use the pool,” he added.

Robinson’s post has gone on to rack up more than 108,000 shares as of Tuesday. According to CNBC, the annual expense of a private room in a nursing home hit the six-figure threshold as of October 2018. Nursing home care is typically meant for people who are not self-sufficient and involves assistance by trained medical staff. The report found in a new study that the national annual median cost of a private room in a nursing home amounted to roughly $100,375. The most expensive place for care in a nursing home in the United States was Alaska, according to the study, where the annual median cost of a room in a nursing home was reportedly $330,873. Washington, D.C., reportedly has the highest cost for a one-bedroom at an assisted living facility, with the annual median cost estimated to be about $111,195.

https://thehill.com/blogs/blog-briefing-room/news/431576-man-goes-viral-with-plan-to-retire-to-a-holiday-inn-instead-of

by Jonathan O’Callaghan

You might be forgiven for thinking our understanding of classical physics had reached its peak in the four centuries since Isaac Newton devised his eponymous laws of motion. But surprising new research shows there are still secrets waiting to be found, hidden in plain sight—or, at least in this case, within earshot.

In a paper published in Physical Review Letters, a group of scientists has theorized that sound waves possess mass, meaning sounds would be directly affected by gravity. They suggest phonons, particlelike collective excitations responsible for transporting sound waves across a medium, might exhibit a tiny amount of mass in a gravitational field. “You would expect classical physics results like this one to have been known for a long time by now,” says Angelo Esposito from Columbia University, the lead author on the paper. “It’s something we stumbled upon almost by chance.”

Esposito and his colleagues built on a previous paper published last year, in which Alberto Nicolis of Columbia and Riccardo Penco from Carnegie Mellon University first suggested phonons could have mass in a superfluid. The latest study, however, shows this effect should hold true for other materials, too, including regular liquids and solids, and even air itself.

And although the amount of mass carried by the phonons is expected to be tiny—comparable with a hydrogen atom, about 10–24 grams—it may actually be measurable. Except, if you were to measure it, you would find something deeply counterintuitive: The mass of the phonons would be negative, meaning they would fall “up.” Over time their trajectory would gradually move away from a gravitational source such as Earth. “If their gravitational mass was positive, they would fall downward,” Penco says. “Because their gravitational mass is negative, phonons fall upwards.” And the amount they would “fall” is equally small, varying depending on the medium the phonon is traveling through. In water, where sound moves at 1.5 kilometers per second, the negative mass of the phonon would cause it to drift at about 1 degree per second. But this corresponds to a change of 1 degree over 15 kilometers, which would be exceedingly difficult to measure.

Difficult it might be, but such a measurement should still be possible. Esposito notes that to distinguish the phonons’ mass, one could look for them in a medium where the speed of sound was very slow. That might be possible in superfluid helium, where the speed of sound can drop to hundreds of meters per second or less, and the passage of a single phonon might shift an atom’s equivalent of material.

Alternatively, instead of seeking minuscule effects magnified by exotic substances, researchers might look for more obvious signs of mass-carrying phonons by closely studying extremely intense sound waves. Earthquakes offer one possibility, Esposito says. According to his calculations, a magnitude 9 temblor would release enough energy so that the resulting change in the gravitational acceleration of the earthquake’s sound wave might be measurable using atomic clocks. (Although current techniques are not sensitive enough to detect the gravitational field of a seismic wave, future advancements in technology might make this possible.)

Sound waves having mass are unlikely to have a major impact on day-to-day life, but the possibility something so fundamental has gone unnoticed for so long is intriguing. “Until this paper, it was thought that sound waves do not transport mass,” says Ira Rothstein from Carnegie Mellon University, who was not involved in this research. “So in that sense it’s a really remarkable result. Because anytime you find any new result in classical physics, given that it’s been around since Newton, you would have thought it would be completely understood. If you look carefully enough, you can find fresh [ideas] even in fields which have been covered for centuries.”

As for why this has never been spotted before, Esposito is uncertain. “Maybe because we are high-energy physicists, gravity is more our language,” he says. “It’s not some theoretical mumbo jumbo kind of thing. In principle people could have discovered it years ago.”

https://www.scientificamerican.com/article/sound-by-the-pound-surprising-discovery-hints-sonic-waves-carry-mass/

by JACINTA BOWLER

Death Valley, the hottest and driest place in North America, isn’t exactly known for record rainfall or pop-up lakes stretching as far as the eye can see.

But after a massive storm lashed the desert with rain and brought chilly temperatures through Southern California, that’s exactly what happened, according to photographer Elliott McGucken.

He was trying to get to Badwater Basin, where he thought there could be flooding, when he saw the giant lake.

“It’s a surreal feeling seeing so much water in the world’s driest place,” McGucken told SF Gate. “There’s an irony even though I couldn’t get down to Badwater Basin. Overall, I think these shots are probably more unique.”

He posted photos of the 16-kilometre-long (10-mile-long) temporary lake, with the Panamint Range in the background, on Instagram.

You don’t actually need that much water for a lake to emerge in this incredibly arid place.

“Because water is not readily absorbed in the desert environment, even moderate rainfall can cause flooding in Death Valley,” weather.com meteorologist Chris Dolce explained. “Flash flooding can happen even where it is not raining. Normally dry creeks or arroyos can become flooded due to rainfall upstream.”

Death Valley is located in Eastern California; during summertime, it can be one of the hottest places in the whole world.

Back in 1972, it clocked the highest natural ground surface temperature on Earth, with a blistering 93.9 degrees Celsius (201 degrees Fahrenheit). And for the last two years, it’s the place where we’ve marked the hottest month ever measured on the planet.

It is also the driest place in all of North America. On a regular year, Death Valley will only receive about two inches (60 mm) of rain.

But there are some pretty amazing sights to be enjoyed when the rains do show up.

According to weather.com, Death Valley’s rainfall on March 5th and 6th was 0.87 inches – nearly triple its whole March rainfall average.

“Rare rainstorms bring vast fields of wildflowers. Lush oases harbour tiny fish and refuge for wildlife and humans,” the National Park Service explains.

“Despite its morbid name, a great diversity of life survives in Death Valley.”

https://www.sciencealert.com/death-valley-just-got-it-s-own-10-mile-long-lake

by PETER DOCKRILL

When bad things happen, we don’t want to remember. We try to block, resist, ignore – but we should perhaps be doing the opposite, researchers say.

A new study led by scientists in Texas suggests the act of intentionally forgetting is linked to increased cerebral engagement with the unwanted information in question. In other words, to forget something, you actually need to focus on it.

“A moderate level of brain activity is critical to this forgetting mechanism,” explains psychologist Tracy Wang from the University of Texas at Austin.

“Too strong, and it will strengthen the memory; too weak, and you won’t modify it.”

Trying to actively forget unwanted memories doesn’t just help prevent your brain from getting overloaded.

It also lets people move on from painful experiences and emotions they’d rather not recall, which is part of the reason it’s an area of active interest to neuroscientists.

“We may want to discard memories that trigger maladaptive responses, such as traumatic memories, so that we can respond to new experiences in more adaptive ways,” says one of the researchers, Jarrod Lewis-Peacock.

“Decades of research has shown that we have the ability to voluntarily forget something, but how our brains do that is still being questioned.”

Much prior research on intentional forgetting has focussed on brain activity in the prefrontal cortex, and the brain’s memory centre, the hippocampus.

In the new study, the researchers monitored a different part of the brain called the ventral temporal cortex, which helps us process and categorise visual stimuli.

In an experiment with 24 healthy young adults, the participants were shown pictures of scenes and people’s faces, and were instructed to either remember or forget each image.

During the experiment, each of the participants had their brain activity monitored by functional magnetic resonance imaging (fMRI) machines.

When the researchers examined activity in the ventral temporal cortex, they found that the act of forgetting effectively uses more brain power than remembering.

“Pictures followed by a forget instruction elicited higher levels of processing in [the] ventral temporal cortex compared to those followed by a remember instruction,” the authors write in their paper.

“This boost in processing led to more forgetting, particularly for items that showed moderate (vs. weak or strong) activation.”

Of course, forgetting specific images on demand in a contrived laboratory experiment is very different to moving on from painful or traumatic memories of events experienced in the real world.

But the mechanisms at work could be the same, researchers say, and figuring out how to activate them could be a huge benefit to people around the world who need to forget things, but don’t know how.

Especially since this finding in particular challenges our natural intuition to suppress things; instead, we should involve more rather than less attention to unwanted information, in order to forget it.

“Importantly, it’s the intention to forget that increases the activation of the memory,” Wang says.

“When this activation hits the ‘moderate level’ sweet spot, that’s when it leads to later forgetting of that experience.”

The findings are reported in JNeurosci.

https://www.sciencealert.com/to-forget-something-you-need-to-think-about-it-neuroscientists-reveal

Back in 1961, the Nobel Prize–winning physicist Eugene Wigner outlined a thought experiment that demonstrated one of the lesser-known paradoxes of quantum mechanics. The experiment shows how the strange nature of the universe allows two observers—say, Wigner and Wigner’s friend—to experience different realities.

Since then, physicists have used the “Wigner’s Friend” thought experiment to explore the nature of measurement and to argue over whether objective facts can exist. That’s important because scientists carry out experiments to establish objective facts. But if they experience different realities, the argument goes, how can they agree on what these facts might be?

That’s provided some entertaining fodder for after-dinner conversation, but Wigner’s thought experiment has never been more than that—just a thought experiment.

Last year, however, physicists noticed that recent advances in quantum technologies have made it possible to reproduce the Wigner’s Friend test in a real experiment. In other words, it ought to be possible to create different realities and compare them in the lab to find out whether they can be reconciled.

And today, Massimiliano Proietti at Heriot-Watt University in Edinburgh and a few colleagues say they have performed this experiment for the first time: they have created different realities and compared them. Their conclusion is that Wigner was correct—these realities can be made irreconcilable so that it is impossible to agree on objective facts about an experiment.

Wigner’s original thought experiment is straightforward in principle. It begins with a single polarized photon that, when measured, can have either a horizontal polarization or a vertical polarization. But before the measurement, according to the laws of quantum mechanics, the photon exists in both polarization states at the same time—a so-called superposition.

Wigner imagined a friend in a different lab measuring the state of this photon and storing the result, while Wigner observed from afar. Wigner has no information about his friend’s measurement and so is forced to assume that the photon and the measurement of it are in a superposition of all possible outcomes of the experiment.

Wigner can even perform an experiment to determine whether this superposition exists or not. This is a kind of interference experiment showing that the photon and the measurement are indeed in a superposition.

From Wigner’s point of view, this is a “fact”—the superposition exists. And this fact suggests that a measurement cannot have taken place.

But this is in stark contrast to the point of view of the friend, who has indeed measured the photon’s polarization and recorded it. The friend can even call Wigner and say the measurement has been done (provided the outcome is not revealed).

So the two realities are at odds with each other. “This calls into question the objective status of the facts established by the two observers,” say Proietti and co.

That’s the theory, but last year Caslav Brukner, at the University of Vienna in Austria, came up with a way to re-create the Wigner’s Friend experiment in the lab by means of techniques involving the entanglement of many particles at the same time.

The breakthrough that Proietti and co have made is to carry this out. “In a state-of-the-art 6-photon experiment, we realize this extended Wigner’s friend scenario,” they say.

They use these six entangled photons to create two alternate realities—one representing Wigner and one representing Wigner’s friend. Wigner’s friend measures the polarization of a photon and stores the result. Wigner then performs an interference measurement to determine if the measurement and the photon are in a superposition.

The experiment produces an unambiguous result. It turns out that both realities can coexist even though they produce irreconcilable outcomes, just as Wigner predicted.

That raises some fascinating questions that are forcing physicists to reconsider the nature of reality.

The idea that observers can ultimately reconcile their measurements of some kind of fundamental reality is based on several assumptions. The first is that universal facts actually exist and that observers can agree on them.

But there are other assumptions too. One is that observers have the freedom to make whatever observations they want. And another is that the choices one observer makes do not influence the choices other observers make—an assumption that physicists call locality.

If there is an objective reality that everyone can agree on, then these assumptions all hold.

But Proietti and co’s result suggests that objective reality does not exist. In other words, the experiment suggests that one or more of the assumptions—the idea that there is a reality we can agree on, the idea that we have freedom of choice, or the idea of locality—must be wrong.

Of course, there is another way out for those hanging on to the conventional view of reality. This is that there is some other loophole that the experimenters have overlooked. Indeed, physicists have tried to close loopholes in similar experiments for years, although they concede that it may never be possible to close them all.

Nevertheless, the work has important implications for the work of scientists. “The scientific method relies on facts, established through repeated measurements and agreed upon universally, independently of who observed them,” say Proietti and co. And yet in the same paper, they undermine this idea, perhaps fatally.

The next step is to go further: to construct experiments creating increasingly bizarre alternate realities that cannot be reconciled. Where this will take us is anybody’s guess. But Wigner, and his friend, would surely not be surprised.

Ref: arxiv.org/abs/1902.05080 : Experimental Rejection of Observer-Independence in the Quantum World

https://www.technologyreview.com/s/613092/a-quantum-experiment-suggests-theres-no-such-thing-as-objective-reality/