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By NICHOLAS BAKALAR Hormonal contraceptives are associated with an increased risk for depression, a large study has found. Danish researchers studied more than a million women ages 15 to 34, tracking their contraceptive and antidepressant use from 2000 to 2013. The study excluded women who before 2000 had used antidepressants or had another psychiatric diagnosis. Over all, compared with nonusers, users of hormonal contraception had an 80 percent increased risk of depression. Some types of contraceptives carried even greater risk. Women who used progestin-only pills more than doubled their risk, for example, while those who used those who used the levonorgestrel IUD (brand name Mirena) tripled their risk. The risk persisted after adjusting for age, age of first intercourse, educational level and other factors. The study, in JAMA Psychiatry, also found that the risk was greater in adolescent girls, but this may be because adolescent girls are especially susceptible to depression. “Even though the risk of depression increases substantially with these drugs — an 80 percent increase is not trivial — most women who use them will not get depressed,” said the senior author, Dr. Oejvind Lidegaard, a clinical professor of obstetrics and gynecology at the University of Copenhagen. “Still, it is important that we tell women that there is this possibility. And there are effective nonhormonal methods of birth control.” © 2016 The New York Times Company
Susan Milius ORLANDO, Fla. — When sex chromosomes among common pill bugs go bad from disuse, borrowed bacterial DNA comes to the rescue. Certain pill bugs grow up female because of sex chromosomes cobbled together with genes that jumped from the bacteria. Genetic analysis traces this female-maker DNA to Wolbachia bacteria, Richard Cordaux, based at the University of Poitiers with France’s scientific research center CNRS, announced September 29 at the International Congress of Entomology. Various kinds of Wolbachia infect many arthropods, spreading from mother to offspring and often biasing their hosts’ sex ratios toward females (and thus creating even more female offspring). In the common pill bug (Armadillidium vulgare), Wolbachia can favor female development two ways. Just by bacterial infection without any gene transfer, bacteria passed down to eggs can make genetic males develop into functional females. Generations of Wolbachia infections determining sex let these pill bugs’ now-obsolete female-making genes degenerate. Which makes it very strange that certain populations of pill bugs with no current Wolbachia infection still produce abundant females. That’s where Cordaux and Poitier colleague Clément Gilbert have demonstrated a second way that Wolbachia makes lady pill bugs — by donating DNA directly to the pill bug genes. The researchers, who share an interest in sex determination, have built a case that Wolbachia inserted feminizing genes into pill bug chromosomes. The bacterial genes thus created a new sex chromosome. 5|© Society for Science & the Public 2000 - 2016
Keyword: Sexual Behavior
Link ID: 22717 - Posted: 10.02.2016
Mia Persson Dogs may look to humans for help in solving impossible tasks thanks to some genes previously linked to social disorders in people. Beagles with particular variants in a gene associated with autism were more likely to sidle up to and make physical contact with a human stranger, researchers report September 29 in Scientific Reports. That gene, SEZ6L, is one of five genes in a particular stretch of beagle DNA associated with sociability in the dogs, animal behaviorist Per Jensen and colleagues at Linköping University in Sweden say. Versions of four of those five genes have been linked to human social disorders such as autism, schizophrenia and aggression. “What we figure has been going on here is that there are genetic variants that tend to make dogs more sociable and these variants have been selected during domestication,” Jensen says. But other researchers say the results are preliminary and need to be confirmed by looking at other dog breeds. Previous genetic studies of dog domestication have not implicated these genes. But, says evolutionary geneticist Bridgett vonHoldt of Princeton University, genes that influence sociability are “not an unlikely target for domestication — as humans, we would be most interested in a protodog that was interested in spending time with humans.” |© Society for Science & the Public 2000 - 2016.
By MAIA SZALAVITZ Drug education is the only part of the middle school curriculum I remember — perhaps because it backfired so spectacularly. Before reaching today’s legal drinking age, I was shooting cocaine and heroin. I’ve since recovered from my addiction, and researchers now are trying to develop innovative prevention programs to help children at risk take a different road than I did. Developing a public antidrug program that really works has not been easy. Many of us grew up with antidrug programs like D.A.R.E. or the Nancy Reagan-inspired antidrug campaign “Just Say No.” But research shows those programs and others like them that depend on education and scare tactics were largely ineffective and did little to curb drug use by children at highest risk. But now a new antidrug program tested in Europe, Australia and Canada is showing promise. Called Preventure, the program, developed by Patricia Conrod, a professor of psychiatry at the University of Montreal, recognizes how a child’s temperament drives his or her risk for drug use — and that different traits create different pathways to addiction. Early trials show that personality testing can identify 90 percent of the highest risk children, targeting risky traits before they cause problems. Recognizing that most teenagers who try alcohol, cocaine, opioids or methamphetamine do not become addicted, they focus on what’s different about the minority who do. © 2016 The New York Times Company
Keyword: Drug Abuse
Link ID: 22715 - Posted: 09.30.2016
By Jessica Boddy Activity trackers like Fitbits and Jawbones help fitness enthusiasts log the calories they burn, their heart rates, and even how many flights of stairs they climb in a day. Biologist Cory Williams of Northern Arizona University in Flagstaff is using similar technology to track the energy consumption of arctic ground squirrels in Alaska—insight that may reveal how the animals efficiently forage for food while avoiding being picked off by golden eagles. This week, Williams published a study in Royal Society Open Science that compared the activity levels of male and female squirrels. He found that although males spend a lot more time outside of their burrows, they’re pretty lazy, and sometimes just bask in the sun during warmer months. Females, on the other hand, have limited time to spare when caring for their young, and use it to run around and forage for themselves and their babies. In addition to previous work on arctic ground squirrel hibernation and seasonal differences in behavior, the finding is helping his team figure out why males tend to be more susceptible to being eaten. Williams sat down with Science to talk about creating a squirrel Fitbit, catching the animals in the wild, and how technology is improving ecological research. This interview has been edited for brevity and clarity. Q: What got you interested in studying arctic ground squirrels? A: It’s one of the only arctic animals that keeps a rigid schedule even when there’s no light/dark cycle for 6 week—meaning, they emerge from and return to their burrows the same time every day and they eat the same time each day, even though the sun stays in the sky for weeks and weeks. So I started to deploy the energy tracking technologies to better understand how the squirrels use energy through the seasons. © 2016 American Association for the Advancement of Science
Keyword: Sexual Behavior
Link ID: 22714 - Posted: 09.30.2016
By Deborah R. Glasofer, Joanna Steinglass Every day on the dot of noon, Jane* would eat her 150-calorie lunch: nonfat yogurt and a handful of berries. To eat earlier, she felt, would be “gluttonous.” To eat later would disrupt the dinner ritual. Jane's eating initially became more restrictive in adolescence, when she worried about the changes her body was undergoing in the natural course of puberty. When she first settled on her lunchtime foods and routine—using a child-size spoon to “make the yogurt last” and sipping water between each bite—she felt accomplished. Jane enjoyed her friends' compliments about her “incredible willpower.” In behavioral science terms, her actions were goal-directed, motivated by achieving a particular outcome. In relatively short order, she got the result she really wanted: weight loss. Years later Jane, now in her 30s and a newspaper reporter, continued to eat the same lunch in the same way. Huddled over her desk in the newsroom, she tried to avoid unwanted attention and feared anything that might interfere with the routine. She no longer felt proud of her behavior. Her friends stopped complimenting her “self-control” years ago, when her weight plummeted perilously low. So low that she has had to be hospitalized on more than one occasion. The longed-for weight loss did not make her feel better about herself or her appearance. Jane's curly hair, once shiny and thick, dulled and thinned; her skin and eyes lost their brightness. There were other costs as well—to her relationships, to her career. Instead of dreaming about a great romance, Jane would dream of the cupcakes she could not let herself have at her niece's birthday party. Instead of thinking about the best lead for her next story, she obsessed over calories and exercise. © 2016 Scientific American
Emily Underwood To human observers, bumblebees sipping nectar from flowers appear cheerful. It turns out that the insects may actually enjoy their work. A new study suggests that bees experience a “happy” buzz after receiving a sugary snack, although it’s probably not the same joy that humans experience chomping on a candy bar. Scientists can’t ask bees or other animals how they feel. Instead, researchers must look for signs of positive or negative emotions in an animal’s decision making or behavior, says Clint Perry, a neuroethologist at Queen Mary University of London. In one such study, for example, scientists shook bees vigorously in a machine for 60 seconds — hard enough to annoy, but not hard enough to cause injury — and found that stressed bees made more pessimistic decisions while foraging for food. The new study, published in the Sept. 30 Science, is the first to look for signs of positive bias in bee decision making, Perry says. His team trained 35 bees to navigate a small arena connected to a plastic tunnel. When the tunnel was marked with a blue flower, the bees learned that a tasty vial of sugar water awaited them at its end. When a green flower was present, there was no reward. Once the bees learned the difference, the scientists threw the bees a curveball: Rather than being blue or green, the flower had a confusing blue-green hue. Faced with the ambiguous blossom, the bees appeared to dither, meandering around for roughly 100 seconds before deciding whether to enter the tunnel. Some didn’t enter at all. But when the scientists gave half the bees a treat — a drop of concentrated sugar water — that group spent just 50 seconds circling the entrance before deciding to check it out. Overall, the two groups flew roughly the same distances at the same speeds, suggesting that the group that had gotten a treat first had not simply experienced a boost in energy from the sugar, but were in a more positive, optimistic state, Perry says. |© Society for Science & the Public 2000 - 2016.
Jon Hamilton What rats can remember may help people who forget. Researchers are reporting evidence that rats possess "episodic memories," the kind of memories that allow us to go back in time and recall specific events. These memories are among the first to disappear in people who develop Alzheimer's disease. The finding, which appears Thursday in Current Biology, suggests that rats could offer a better way to test potential drugs for Alzheimer's. Right now, most of these drugs are tested in mice. "We need to have a way to study the exact type of memory that we think is impaired in Alzheimer's disease," says Bruce Lamb, a professor of medical and molecular genetics at Indiana University in Indianapolis. He was not involved in the study. The lack of an adequate animal model of Alzheimer's disease may be one reason drugs that seemed to work in mice have failed when given to people, Lamb says. Loss of episodic memories, especially recent ones, is a key sign of Alzheimer's, says Jonathon Crystal, an author of the study and director of the neuroscience program at Indiana University in Bloomington. "So if you visit your grandmother who has Alzheimer's, [she] isn't going to remember that you were visiting a couple of weeks ago and what you described about things that are going on in your life," he says. Crystal and a team of researchers thought rats might have some form of episodic memory. So they began doing studies that relied on the animals' remarkable ability to recognize a wide range of odors, like basil and banana and strawberry. © 2016 npr
Link ID: 22711 - Posted: 09.30.2016
By Carl Hart In early August the Drug Enforcement Administration declined to reclassify marijuana under the federal Controlled Substances Act. The drug is currently listed on Schedule I, meaning that it is viewed as having “no currently accepted medical use in treatment” and is therefore technically banned by federal law. The proposed change would have moved it to Schedule II, where it would join morphine, opium and codeine. That would make marijuana potentially available by prescription nationwide. Such a change would have been good for patients and scientists, and it would have represented a big step toward resolving the hypocritical mess that characterizes current law. Despite many people's assumptions to the contrary, the existing law does not ban scientific investigation into the harms and benefits of the drug. It's true that scientists studying marijuana must jump through multiple bureaucratic and regulatory hoops, and one of these just became a bit easier to navigate. Currently researchers who want to study the drug must get it from the University of Mississippi, which is the only university now permitted to grow marijuana plants for research purposes. When the DEA announced in August that it would not reschedule marijuana, it did say that it would let other institutions apply for permission to start growing the plants as well. That was a step in the right direction—but it's not enough. Despite the regulatory barriers, dozens of scientists—myself included—have been engaged in research on the harms and benefits of marijuana for decades, and the evidence shows that the drug has many helpful therapeutic uses. For example, it stimulates appetite in HIV-positive patients, which could be a lifesaver for someone suffering from AIDS wasting syndrome. It is also useful in the treatment of neuropathic pain, chronic pain, and spasticity caused by multiple sclerosis. © 2016 Scientific American
Keyword: Drug Abuse
Link ID: 22710 - Posted: 09.30.2016
By CATHERINE SAINT LOUIS Increasing numbers of children have high blood pressure, largely as a consequence of their obesity. A growing body of evidence suggests that high blood pressure may impair children’s cognitive skills, reducing their ability to remember, pay attention and organize facts. In the most comprehensive study to date, published on Thursday in The Journal of Pediatrics, 75 children ages 10 to 18 with untreated high blood pressure performed worse on several tests of cognitive function, compared with 75 peers who had normal blood pressure. The differences were subtle, and the new research does not prove that high blood pressure diminishes cognitive skills in children. Still, the findings set off alarm bells among some experts. “This study really shows there are some differences,” said Dr. David B. Kershaw, the director of pediatric nephrology at C. S. Mott Children’s Hospital at the University of Michigan, who was not involved with the research. “This was not just random chance.” Dr. Marc B. Lande, a professor of pediatric nephrology at the University of Rochester Medical Center, and his colleagues had children tested at four sites in three states, matching those with and without high blood pressure by age, maternal education, race, obesity levels and other factors. The researchers excluded children with learning disabilities and sleep problems, which can affect cognitive skills. Children with elevated blood pressure performed worse than their peers on tests of memory, processing speed and verbal skills, the researchers found. But all the scores were still in the normal range. Because of increased obesity, elevated blood pressure, also called hypertension, is no longer rare in children, though it is underdiagnosed. In a recent survey, about 3.5 percent of 14,187 children ages 3 to 18 had hypertension. © 2016 The New York Times Company
Hannah Devlin Science correspondent Scientists have found the most definitive evidence yet that some people are destined to age quicker and die younger than others - regardless of their lifestyle. The findings could explain the seemingly random and unfair way that death is sometimes dealt out, and raise the intriguing future possibility of being able to extend the natural human lifespan. “You get people who are vegan, sleep 10 hours a day, have a low-stress job, and still end up dying young,” said Steve Horvath, a biostatistician who led the research at the University of California, Los Angeles. “We’ve shown some people have a faster innate ageing rate.” A higher biological age, regardless of actual age, was consistently linked to an earlier death, the study found. For the 5% of the population who age fastest, this translated to a roughly 50% greater than average risk of death at any age. Intriguingly, the biological changes linked to ageing are potentially reversible, raising the prospect of future treatments that could arrest the ageing process and extend the human lifespan. “The great hope is that we find anti-ageing interventions that would slow your innate ageing rate,” said Horvath. “This is an important milestone to realising this dream.” Horvath’s ageing “clock” relies on measuring subtle chemical changes, in which methyl compounds attach or detach from the genome without altering the underlying code of our DNA. © 2016 Guardian News and Media Limited
Rebecca Hersher A new study of violent behavior in more than 1,000 mammal species found the meerkat is the mammal most likely to be murdered by one of its own kind. The study, led by José María Gómez of the University of Grenada in Spain and published Wednesday in the journal Nature, analyzed more than 4 million deaths among 1,024 mammal species and compared them with findings in 600 studies of violence among humans from ancient times until today. The findings tell us two things: Some amount of violence between humans is attributable to our place on the evolutionary tree. Meerkats are surprisingly murderous. To be clear, the study's authors did not set out to prove (or disprove) a theory of meerkat violence; they were investigating what mammalian data might tell us about humans. But Ed Yong at The Atlantic organized the study's exhaustive list of mammals to make this helpful chart ranking animals by their murderousness. Some of the animals with reputations for docility are actually more dangerous to each other than creatures known for their aggression. Chinchillas kill each other more often than brown bears turn on their own kind. New Zealand sea lions are more murderous than actual lions. And, as you can see, about 20 percent of meerkat deaths are murders. Their violence has been documented; a 2006 study described in National Geographic documented meerkat mothers killing the offspring of other females to maintain dominance. © 2016 npr
Link ID: 22707 - Posted: 09.29.2016
By Clare Wilson IT HAS been blamed for brain shrinkage, impotence, divorce and paedophilia – and in April this year, Utah declared it a public health hazard. Warnings about pornography come not just from religious or conservative groups – former Playboy model and actor Pamela Anderson also recently cautioned against its “corrosive effects”. Yet survey after survey shows porn use is common among men and not exactly rare in women, so can it really be so dangerous? Or could it even have benefits? While there is research into the effects of porn, a great deal of it is contradictory. Even the same studies are interpreted differently by those on opposite sides of the debate. Some feel it is a menace to society, while others think that attitude belongs with 1980s hysteria over video nasties. Anti-porn campaigners chiefly argue that it is addictive and hijacks the brain’s normal reward pathways. Like heroin addicts who crave more of their drug to get the same high, users find they are no longer aroused by real sex and resort to increasingly harder-core material, or so the theory goes. Of course, there are other concerns over pornography, such as its depictions of violence, exploitation and sexual consent. But male addiction is an increasing focus of anti-porn campaigns. Campaigners say that an excess of porn prompts users to spurn their partners and seek out images of bestiality, rape scenes, and child abuse. Some schools in Scotland now warn that viewing adult images leads to impotence, coercion and abuse. “This kind of escalation is described over and over again,” says Gary Wilson, a retired biology lecturer and author of website and book Your Brain on Porn. © Copyright Reed Business Information Ltd.
Keyword: Sexual Behavior
Link ID: 22706 - Posted: 09.29.2016
By Edd Gent, A brain-inspired computing component provides the most faithful emulation yet of connections among neurons in the human brain, researchers say. The so-called memristor, an electrical component whose resistance relies on how much charge has passed through it in the past, mimics the way calcium ions behave at the junction between two neurons in the human brain, the study said. That junction is known as a synapse. The researchers said the new device could lead to significant advances in brain-inspired—or neuromorphic—computers, which could be much better at perceptual and learning tasks than traditional computers, as well as far more energy efficient. "In the past, people have used devices like transistors and capacitors to simulate synaptic dynamics, which can work, but those devices have very little resemblance to real biological systems. So it's not efficient to do it that way, and it results in a larger device area, larger energy consumption and less fidelity," said study leader Joshua Yang, a professor of electrical and computer engineering at the University of Massachusetts Amherst. [10 Things You Didn't Know About the Brain] Previous research has suggested that the human brain has about 100 billion neurons and approximately 1 quadrillion (1 million billion) synapses. A brain-inspired computer would ideally be designed to mimic the brain's enormous computing power and efficiency, scientists have said. © 2016 Scientific American
By GRETCHEN REYNOLDS Before you skip another workout, you might think about your brain. A provocative new study finds that some of the benefits of exercise for brain health may evaporate if we take to the couch and stop being active, even just for a week or so. I have frequently written about how physical activity, especially endurance exercise like running, aids our brains and minds. Studies with animals and people show that working out can lead to the creation of new neurons, blood vessels and synapses and greater overall volume in areas of the brain related to memory and higher-level thinking. Presumably as a result, people and animals that exercise tend to have sturdier memories and cognitive skills than their sedentary counterparts. Exercise prompts these changes in large part by increasing blood flow to the brain, many exercise scientists believe. Blood carries fuel and oxygen to brain cells, along with other substances that help to jump-start desirable biochemical processes there, so more blood circulating in the brain is generally a good thing. Exercise is particularly important for brain health because it appears to ramp up blood flow through the skull not only during the actual activity, but throughout the rest of the day. In past neurological studies, when sedentary people began an exercise program, they soon developed augmented blood flow to their brains, even when they were resting and not running or otherwise moving. But whether those improvements in blood flow are permanent or how long they might last was not clear. So for the new study, which was published in August in Frontiers in Aging Neuroscience, researchers from the department of kinesiology at the University of Maryland in College Park decided to ask a group of exceedingly fit older men and women to stop exercising for awhile. © 2016 The New York Times Company
By Allison Bond, Although neurologist Amie Hsia was hundreds of miles away from the emergency room team caring for her ailing aunt last February, she knew her symptoms and imaging pointed to a severe stroke. Hsia’s aunt needed treatment fast with a clot-busting medicine and a procedure known as an endovascular thrombectomy, which removes the clot and restores blood flow to oxygen-starved patches of the brain. The hospital caring for her wasn’t equipped to perform the surgery, however, so Hsia insisted she be transferred to a nearby hospital, where the clot was removed from her brain. Hsia’s aunt survived and is able to live independently, despite some remaining symptoms from the stroke. Still, the travel to another hospital cost her valuable time—and could have hurt her in the long run. That’s the implication of a study published Monday in the Journal of the American Medical Association that found that the sooner patients with severe strokes receive a thrombectomy, the less disabled they tend to be three months later. The research indicates that the brain-saving benefits of thrombectomy are most pronounced within the first few hours after signs of a stroke begin, and that these effects decline with each passing hour. To some experts, the study is a call to rejigger the current method of determining where ambulances ought to take stroke patients, which is based solely on proximity. Instead, they say, patients with apparent severe strokes should be rushed to hospitals that perform thrombectomies. © 2016 Scientific America
Link ID: 22703 - Posted: 09.28.2016
By Nick Purdon, Leonardo Palleja, CBC News If you met Lisa James, chances are you'd never guess she injects herself with heroin twice a day. She's a devoted mom to her daughter Tia, 24, who has a rare neurological disorder that causes tumours to grow on her spine and brain. She comforts Tia when she's overcome with nausea. She's by her side when she visits doctors. "My relationship with my daughter is better than it's ever been," says James, 48. But James says it wasn't so long ago, her days were spent doing absolutely anything to score heroin. She used to steal hundreds of dollars' worth of meat from grocery stores and sell it on the streets. She even stole from Tia. "I took $500 out of her account and because of the lovely girl that she is, she never wanted to make me feel bad," James says. "If someone had told me I would do something so despicable — I never would have believed it." She says that all changed when she was accepted to the Providence Crosstown Clinic in Vancouver's Downtown Eastside, where she's buzzed in every morning at 9 a.m. She sits down in a sterile room and injects a syringe full of free heroin into her arm. ©2016 CBC/Radio-Canada.
Keyword: Drug Abuse
Link ID: 22702 - Posted: 09.28.2016
Ramin Skibba. Physiologist Ivan Pavlov conditioned dogs to associate food with the sound of a buzzer, which left them salivating. Decades later, researchers discovered such training appears to block efforts to teach the animals to link other stimuli to the same reward. Dogs trained to expect food when a buzzer sounds can then be conditioned to salivate when they are exposed to the noise and a flash of light simultaneously. But light alone will not cue them to drool. This ‘blocking effect’ is well-known in psychology, but new research suggests that the concept might not be so simple. Psychologists in Belgium failed to replicate the effect in 15 independent experiments, they report this month in the Journal of Experimental Psychology1. “For a long time, you tend to think, ‘It’s me’ — I’m doing something wrong, or messing up the experiment,’” says lead author Tom Beckers, a psychologist at the Catholic University of Leuven (KU Leuven) in Belgium. But after his student, co-author Elisa Maes, also could not replicate the blocking effect, and the team failed again in experiments in other labs, Beckers realized that “it can’t just be us”. The scientists do not claim that the blocking effect is not real, or that previous observations of it are wrong. Instead, Beckers thinks that psychologists do not yet know enough about the precise conditions under which it applies. © 2016 Macmillan Publishers Limited,
Keyword: Learning & Memory
Link ID: 22701 - Posted: 09.27.2016
By Abdul-Kareem Ahmed In the world of recreational and professional sports, many athletes—particularly in contact sports—suffer concussions. These mild traumatic brain injuries cause headaches, memory problems and confusion, but usually resolve on their own with rest. Some players, however, especially after repeated concussions, continue to experience symptoms for many months—a phenomenon termed post-concussion syndrome. A few of these players will eventually develop chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disease that causes dementia symptoms similar to Alzheimer’s disease. CTE can lead to personality changes, movement problems and, sometimes, mortality. CTE is diagnosed after death because it requires postmortem examination of a player’s brain. Post-concussion syndrome, in contrast, is diagnosed based on patient symptoms. To date, doctors do not have any objective tests to determine syndrome severity or relate it to the risk of developing CTE. Now, a group of researchers from Sweden and the U.K. say they have developed such a test, reporting their findings last week in JAMA Neurology. The test measures biomarkers in the cerebrospinal fluid—the colorless liquid that supports and suspends the brain and spinal cord—that appear to provide a measure of concussion severity and CTE risk. The researchers collected cerebrospinal fluid via spinal taps from 16 professional Swedish ice hockey players and a similar number of healthy individuals. The hockey players had all experienced post-concussion syndrome, causing nine of them to retire from the game. © 2016 Scientific American,
By KEN BELSON One of the frustrations of researchers who study chronic traumatic encephalopathy, the degenerative brain disease linked to repeated head hits, is that it can be detected only in autopsies, and not in the living. Researchers, though, have been trying to solve this problem in two primary ways: by identifying biomarkers linked to the disease that show up on imaging tests in certain locations in the brain, and by trying to locate in the blood the protein that is the hallmark of the disease. On Monday, two groups of researchers said they had made what they considered small steps in developing both methods. The announcements are small parts of much larger studies that will take years to bear fruit, if they ever do. Both methods have been questioned by detractors, some of whom say the hype is getting ahead of the science. Scientists, these critics note, have spent decades trying to find ways to accurately diagnose Alzheimer’s disease, which has some of the same characteristics as C.T.E. Still, at a medical conference in Boston on Monday, Robert Stern, a professor of neurology at Boston University, said technology developed by the company Quanterix (paid for in part with a grant from the N.F.L.) had identified elevated levels of tau proteins in blood samples of 96 former football players between 40 and 69 years old, compared with only 25 people of the same age in a control group. The results, which are part of a seven-year study and are under review for publication, are preliminary because they identify only the total amount of tau in the blood, not the amount of the specific tau linked to C.T.E. Additional tests are being done in Sweden to determine the amount of the C.T.E.-related tau in the blood samples, Stern said. Even so, Stern said, the blood samples from the 96 former players suggest that absorbing repeated head hits earlier in life can lead to higher concentrations of tau in the blood later. © 2016 The New York Times Company