Why China's rule changes are hitting US markets

27 Mins AgoCNBC.com New rules for trading Chinese stocks spooked European and U.S. markets on Friday. (Tweet This) Chinese exchanges and regulators announced Friday that they would crack down on over-the-counter margin trading and that they would allow fund managers to lend shares for short-selling. The type of stocks that investors can short sell will also be expanded soon to 1,100, from 900 currently. All of these moves could slow Chinese equities' wild run higher in recent months. Read MorePerfect storm for market correction: Expert ChinaFotoPress | Getty Images Investors observe stock market at a stock exchange corporation on April 17, 2015 in Jiujiang, Jiangxi province of China. Although the Shanghai Stock Exchange Composite Index rose 2.2 percent in Friday trading, Chinese after-hours stock futures fell about 5.5 percent in a response to the new regulations. Traders said U.S. and European markets were then in turn spooked by the move in those futures, and worries that the regulatory changes would be negative for the flow of recent money that has poured into Chinese exchanges. "The securities regulator is encouraging short-selling to institutional investors, and they are going to stop margin trading on OTC," Ioan Smith, managing director of KCG Europe, said. "Traders had to catch up with that news after the Bloomberg terminals came back online, and that's when we saw the falls in Europe." (Terminals were briefly down earlier Friday) Read MoreSee how US markets are trading here News of the Chinese changes followed comments from the China Securities Regulatory Commission indicating the agency expected future good fortunes for equities. Xiao Gang, who leads the CSRC, said investors should not think they are missing the boat if they had not yet invested in the Chinese stock market, which has surged around 70 percent since November. "So apparently they told us that the bull market in Chinese stocks was going to last, and then they pulled the rug? I is confused," Rhino Trading Partners' Michael Block (actually) wrote in a Friday note. He attributed a 14 point decline in S&P futures and a 4 percent decline in the iShares China Large-Cap exchange traded fund to this news. European shares also traded down in part because of the China news, Block added. "I didn't realize China would have such an effect on the U.S. and Europe," he wrote. "The [Shanghai Stock Exchange Composite Index] is up over 32% this year. The [S&P 500] is barely up over 2%. But c'est la vie, apparently." Although there has not been a perfect correlation between U.S. stocks and booming Chinese equities, any worries about the future of those markets would cause some doubts stateside, according to Jim Meyer, CEO of Tower Bridge Advisors. "The Chinese market has been a source of strength," he explained, so any decline could rattle equities traders. Read MoreForget China, this market is Asia's sweet spot Any global weakness from the Chinese regulatory changes should be temporary, however, said Adrian Day of Adrian Day Asset Management. Such a move was not unexpected, he said, given the fact that Chinese equities "have sort of gone crazy" with massive gains in recent months. And while the new rules may tamp down on those prices, the easily-spooked global markets should move along to the next focal point. "By next week the rest of the world will have forgotten about it," Day said. —Reuters and CNBC's Evelyn Cheng contributed to this report.

Patents forecast technological change

Thu, 04/16/2015 - 12:20pm MIT News Office How fast is online learning evolving? Are wind turbines a promising investment? And how long before a cheap hoverboard makes it to market? Attempting to answer such questions requires knowing something about the rate at which a technology is improving. Now engineers at Massachusetts Institute of Technology (MIT) have devised a formula for estimating how fast a technology is advancing, based on information gleaned from relevant patents. The researchers determined the improvement rates of 28 different technologies, including solar photovoltaics, 3-D printing, fuel-cell technology and genome sequencing. They searched through the U.S. Patent Office database for patents associated with each domain—more than 500,000 total—by developing a novel method to quickly and accurately select the patents that best represent each technology. Once these were identified, the researchers analyzed certain metrics across patents in each domain, and found that some were more likely to predict a technology’s improvement rate than others. In particular, forward citations—the number of times a patent is cited by subsequent patents—is a good predictor, as is the date of a patent’s publication: Technologies with more recent patents are likely innovating at a faster rate than those with older patents. The team devised an equation incorporating a patent set’s average forward citation and average publication date, and calculated the rate of improvement for each technology domain. Their results matched closely with the rates determined through the more labor-intensive approach of finding numerous historical performance data points for each technology. Among the 28 domains analyzed, the researchers found the fastest-developing technologies include optical and wireless communications, 3-D printing and MRI technology, while domains such as batteries, wind turbines and combustion engines appear to be improving at slower rates. Chris Benson, a former graduate student in MIT’s Dept. of Mechanical Engineering, says the new prediction tool may be of interest to venture capitalists, startups and government and industry labs looking to explore new technology. “There’s a lot of nuance to our method, and I don’t see it as something to hand out to the masses to play with,” says Benson, who helped developed the prediction tool. “I see it more as something where we work with somebody to help them understand what the future technological capabilities that they’re interested in are. We’re probably more like a real estate agent, and less like Zillow.” Benson and Chris Magee, a professor of the practice of engineering systems at MIT, have published their results in PLoS ONE. The paper contains the fundamental findings and equations relating technological improvement to a variety of patent characteristics. Technological dynamism In 2003, Magee began determining the improvement rates of various technologies. At the time, he was curious how technologies were developing relative to Moore’s Law—an observation pertaining originally to computers, in which transistors on a computer chip double every two years. “There were a lot of things that weren’t going as fast as Moore’s Law, and I started trying to get measures of them,” Magee recalls. Magee initially approached the problem on a case-by-case basis, determining which metrics best represent productivity for a given domain. He then compiled data for each metric, such as the price and speed of manufacturing a product, and used the data to calculate the overall rate of improvement. In 2010, he realized that one of the most comprehensive resources on technology lay in the U.S. patent record. “We thought, ‘Maybe there’s enough information there that we can do something about linking it to the dynamism of technical change,’” Magee says. For several years, he and his group identified the most relevant patents in a technological domain, by literally reading through thousands of patents—an incredibly time-intensive process. The approach was not very reliable, as two people may choose entirely different sets of patents to represent the same technology. A “Standard & Poor’s” for technology In 2012, Magee and Benson came up with a more efficient, repeatable method for identifying relevant patent sets, by looking at the overlap between the U.S. and international patent-classification systems. For each patent accepted by the U.S. Patent Office, a patent reviewer will file the patent under several classes within both classification systems. For instance, a solar photovoltaics patent may be entered under the U.S. classes “batteries” and “active solid-state devices” and within the international system as “semiconductor devices.” The team found that by looking for patent overlap between both classification systems, they could repeatedly identify the same set of patents that best represent a technology, within a matter of hours, rather than months. Once they identified a relevant set of patents, the researchers looked for metrics within patents that they could use to calculate a technology’s rate of improvement. They found that a patent set’s average forward citations within the first three years after publication, and the average date of publication, were the best predictors of technological improvement. Benson says they were also able to weed out less-helpful patent information. “If a technology has more patents in general, it should be moving faster, but that turns out not to be the case,” Benson says. “3-D printing only has 300 to 500 patents, and that’s improving at the same rate as semiconductors, which have about 150,000 patents. So there’s almost zero correlation.” The team devised a simple equation incorporating forward citation and publication date, and used the method to predict improvement rates for 28 technologies. The researchers then compared the rates with those they previously obtained using their more time-intensive, historical data-based approach, and found the results from both methods matched closely. They then used their more efficient approach to predict the improvement rates of 11 emerging technologies in the next 10 years. Among these, the fastest-growing domains appear to be online learning and digital representation, while slower technologies include food engineering and nuclear fusion. Doyne Farmer, a professor of mathematics at Oxford Univ., says that the notion that technological progress is predictable “is both intellectually fascinating and quite powerful in its practical implications.” “[The group’s] methods should be useful to any organization that is considering investments in technology, in particular government funding agencies such as the [U.S. Department of Energy] that fund engineering applications; venture-capital firms; or firms that are actually in the technology business,” says Farmer, who was not involved in the research. “Making the right bets on technological progress is essential for solving problems such as climate change. Thus, we should all benefit from this work.” Magee hopes the method may be used much like a rating system, similar to Standard & Poor’s and other stock-market indices. Such ratings could be useful for investors looking for the next big breakthrough, as well as scientific labs that are contemplating new research directions. Magee says knowing how various technologies may improve in the next decade could give innovators an idea of when “feeder technologies” may mature, and enable more pie-in-the-sky ideas, like mass-produced hoverboards and flying cars. “We can help reduce the uncertainty of the capabilities of a technology in the future, not to zero, but to a more manageable number,” Benson says. “I believe that’s valuable in a lot of different ways.” Source: Massachusetts Institute of Technology

Scientists discover protein that boosts immunity to viruses and cancer

April 16, 2015 Imperial College London Scientists have discovered a protein that plays a central role in promoting immunity to viruses and cancer, opening the door to new therapies. Experiments in mice and human cells have shown that the protein promotes the proliferation of cytotoxic T cells, which kill cancer cells and cells infected with viruses. The discovery was unexpected because the new protein had no known function and doesn’t resemble any other protein. Scientists have discovered a protein that plays a central role in promoting immunity to viruses and cancer, opening the door to new therapies. Experiments in mice and human cells have shown that the protein promotes the proliferation of cytotoxic T cells, which kill cancer cells and cells infected with viruses. The discovery was unexpected because the new protein had no known function and doesn’t resemble any other protein. Researchers from Imperial College London who led the study are now developing a gene therapy designed to boost the infection-fighting cells, and hope to begin human trials in three years.  The study also involved researchers at Queen Mary University of London, ETH Zurich and Harvard Medical School. Their discovery, which has been six years in the making, is reported today in the journal Science. Cytotoxic T cells are an important component of the immune system, but when faced with serious infections or advanced cancer, they are often unable to proliferate in large enough quantities to fight the disease. By screening mice with genetic mutations, the Imperial team discovered a strain of mice that produced 10 times as many cytotoxic T cells when infected with a virus compared with normal mice. These mice suppressed the infection more effectively, and were more resistant to cancer. They also produced more of a second type of T cells, memory cells, enabling them to recognise infections they have encountered previously and launch a rapid response. The mice with enhanced immunity produced high levels of a hitherto unknown protein, which the researchers named lymphocyte expansion molecule, or LEM. They went on to show that LEM modulates the proliferation of human T cells as well as in mice. The researchers now aim to develop a gene therapy designed to improve immunity by boosting the production of LEM. With the support of Imperial Innovations, the technology commercialisation company for the College, the researchers have filed two patents. A company called ImmunarT has been formed with the aim of commercialising the technology. Professor Philip Ashton-Rickardt from the Section of Immunobiology in the Department of Medicine at Imperial, who led the study, said: “Cancer cells have ways to suppress T cell activity, helping them to escape the immune system. Genetically engineering T cells to augment their ability to fight cancer has been a goal for some time and techniques for modifying them already exist. By introducing an active version of the LEM gene into the T cells of cancer patients, we hope we can provide a robust treatment for patients.  “Next we will test the therapy in mice, make sure it is safe and see if it can be combined with other therapies. If all goes well, we hope to be ready to carry out human trials in about three years.” Dr Claudio Mauro, who led the research from the Centre for Biochemical Pharmacology, based within Queen Mary University of London’s William Harvey Research Institute, said: “This study has identified the novel protein LEM and unlocked an unexpected way of enhancing the ability of our immune system to fight viruses or cancers. This is based on the ability of the protein LEM to regulate specific energy circuits, and particularly mitochondrial respiration, in a subset of white blood cells known as cytotoxic T cells. This discovery has immediate consequences for the delivery of innovative therapeutic approaches to cancer. Its ramifications, however, are far greater as they can help explaining the biological mechanisms of widespread human diseases involving altered immune and inflammatory responses. These include chronic inflammatory and autoimmune disorders, such as atherosclerosis and rheumatoid arthritis.” The research was funded by the Medical Research Council, the Wellcome Trust and the British Heart Foundation. Dr Mike Turner, Head of Infection and Immunobiology at The Wellcome Trust, said: “The discovery of a protein that could boost the immune response to not only cancer, but also to viruses, is a fascinating one. Further investigation in animal models is needed before human trials can commence, but there is potential for a new type of treatment that capitalises on the immune system’s innate ability to detect and kill abnormal cells.”

Facebook users' wishful thinking: Cyberbullying, depression won't happen to me

April 16, 2015 Dartmouth College Facebook users with so-called optimistic bias think they're less likely than other users to experience cyberbullying, depression and other negative social and psychological effects from using the site, a study finds. The study suggests that optimistic bias, or an intrinsic tendency to imagine future events in a favorable light that enhances positive self-regard -- in other words, wishful thinking -- leaves those Facebook users vulnerable to the negative realities of social media. Facebook users with so-called optimistic bias think they're less likely than other users to experience cyberbullying, depression and other negative social and psychological effects from using the site, a Dartmouth-Cornell study finds. The study suggests that optimistic bias, or an intrinsic tendency to imagine future events in a favorable light that enhances positive self-regard -- in other words, wishful thinking -- leaves those Facebook users vulnerable to the negative realities of social media. The findings appear in the journal Cyberpsychology, Behavior, and Social Networking. "Our findings demonstrate important and novel discrepancies in how people perceive themselves and others concerning the positive and negative outcomes of Facebook use," says lead author Sunny Jung Kim, a postdoctoral research associate in the Psychiatric Research Center and the Center for Technology and Behavioral Health at the Geisel School of Medicine at Dartmouth. "A growing number of studies report possible benefits and risks of using Facebook and other social media, ranging from effects on self-esteem to cyberbullying. But little is known about how people perceive themselves to be likely to experience these mixed outcomes and what the implications of having these perceptions are." In the new study, the researchers surveyed 237 active Facebook users between ages 18 and 37. The participants were asked to assess their own and other people's likelihood of experiencing positive and negative outcomes on Facebook. They also were asked to rate their likelihood of supporting Internet regulations, their personal Facebook involvement and their attitudes toward Facebook use. The results show that Facebook users with optimistic bias tend to show strong support for Internet regulations to protect other users from social ostracizing, although not from psychologically negative effects, including depression and loneliness. The lack of support regarding psychological harms may be because mental health effects are perceived as less amenable to regulation or because their importance is underestimated, the researchers say. The results also show that Facebook users who view the site negatively or who use it infrequently think other people are more likely than themselves to have positive experiences on the site, a reversed optimistic bias that is new and intriguing. "When ostensibly positive outcomes, such as receiving social support from Facebook friends, are perceived to be unusual and irrelevant for themselves, the direction of the optimistic bias for these objectively positive outcomes can be dampened or even reversed," Kim says. Co-author Cornell Professor Jeffrey Hancock adds: "It's fascinating that well-established, third-person effects are also seen on Facebook, but the reversal shows how social media is not identical to mass media." "Although some might argue that it is still premature to claim that Facebook use is a direct predictor of extreme events such as clinical depression and suicidal attempts, a growing line of research indicates that negative events such as Facebook cyberbullying can result in detrimental consequences, including depression and substance use problems," Kim says. "Without adequate protections, the damage of these critical events can be severe. This is especially the case for those in a vulnerable health condition, in which this optimistic bias for risk events can leave them unprepared without adequate health protective behaviors. We argue that Facebook may serve as a source of emotional support between users and as a platform to disseminate protective health messages to prevent negative psychological consequences of Facebook use. Given that negative personal and health news such as stressful events and depressive symptoms are frequently shared on Facebook, it may be an important site for observing negative psychological states of users." Story Source: The above story is based on materials provided by Dartmouth College. Note: Materials may be edited for content and length. Journal Reference: Sunny Jung Kim, Jeffrey T. Hancock. Optimistic Bias and Facebook Use: Self–Other Discrepancies About Potential Risks and Benefits of Facebook Use. Cyberpsychology, Behavior, and Social Networking, 2015; 18 (4): 214 DOI: 10.1089/cyber.2014.0656

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Eight nutrients to protect the aging brain

 

Brain health is the second most important component in maintaining a healthy lifestyle according to a 2014 AARP study. As people age they can experience a range of cognitive issues from decreased critical thinking to dementia and Alzheimer's disease. In the March issue of Food Technology published by the Institute of Food Technologists (IFT), contributing editor Linda Milo Ohr writes about eight nutrients that may help keep your brain in good shape. 1. Cocoa Flavanols: Cocoa flavanols have been linked to improved circulation and heart health, and preliminary research shows a possible connection to memory improvement as well. A study showed cocoa flavanols may improve the function of a specific part of the brain called the dentate gyrus, which is associated with age-related memory (Brickman, 2014). 2. Omega-3 Fatty Acids: Omega-3 fatty acids have long been shown to contribute to good heart health are now playing a role in cognitive health as well. A study on mice found that omega-3 polyunsaturated fatty acid supplementation appeared to result in better object recognition memory, spatial and localizatory memory (memories that can be consciously recalled such as facts and knowledge), and adverse response retention (Cutuli, 2014). Foods rich in omega-3s include salmon, flaxseed oil, and chia seeds. 3. Phosphatidylserine and Phosphatidic Acid: Two pilot studies showed that a combination of phosphatidylserine and phosphatidic acid can help benefit memory, mood, and cognitive function in the elderly (Lonza, 2014). 4. Walnuts: A diet supplemented with walnuts may have a beneficial effect in reducing the risk, delaying the onset, or slowing the progression of Alzheimer's disease in mice (Muthaiyah, 2014). 5. Citicoline: Citicoline is a natural substance found in the body's cells and helps in the development of brain tissue, which helps regulate memory and cognitive function, enhances communication between neurons, and protects neural structures from free radical damage. Clinical trials have shown citicoline supplements may help maintain normal cognitive function with aging and protect the brain from free radical damage. (Kyowa Hakko USA). 6. Choline: Choline, which is associated with liver health and women's health, also helps with the communication systems for cells within the brain and the rest of the body. Choline may also support the brain during aging and help prevent changes in brain chemistry that result in cognitive decline and failure. A major source of choline in the diet are eggs. 7. Magnesium: Magnesium supplements are often recommended for those who experienced serious concussions. Magnesium-rich foods include avocado, soy beans, bananas and dark chocolate. 8. Blueberries: Blueberries are known to have antioxidant and anti-inflammatory activity because they boast a high concentration of anthocyanins, a flavonoid that enhances the health-promoting quality of foods. Moderate blueberry consumption could offer neurocognitive benefits such as increased neural signaling in the brain centers. Story Source: The above story is based on materials provided by Institute of Food Technologists (IFT). Note: Materials may be edited for content and length.

Alcohol use: If you drink, keep it moderate

 

Alcohol use can be a slippery slope. Moderate drinking can offer some health benefits. But heavy drinking can have serious consequences. By Mayo Clinic Staff It sounds like a mixed message: Drinking alcohol may offer some health benefits, especially for your heart. On the other hand, alcohol may increase your risk of health problems and damage your heart. So which is it? When it comes to drinking alcohol, the key is doing so only in moderation. Certainly, you don't have to drink any alcohol, and if you currently don't drink, don't start drinking for the possible health benefits. In some cases, it's safest to avoid alcohol entirely — the possible benefits don't outweigh the risks. Here's a closer look at the connection between alcohol and your health. Health benefits of moderate alcohol use Moderate alcohol consumption may provide some health benefits. It may: Reduce your risk of developing and dying from heart disease Possibly reduce your risk of ischemic stroke (when the arteries to your brain become narrowed or blocked, causing severely reduced blood flow) Possibly reduce your risk of diabetes Even so, the evidence about the possible health benefits of alcohol isn't certain, and alcohol may not benefit everyone who drinks. Guidelines for moderate alcohol use If you choose to drink alcohol, do so only in moderation. For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger. Examples of one drink include: Beer: 12 fluid ounces (355 milliliters) Wine: 5 fluid ounces (148 milliliters) Distilled spirits (80 proof): 1.5 fluid ounces (44 milliliters) Moderate alcohol use may be of most benefit if you're an older adult or if you have existing risk factors for heart disease. If you're a middle-aged or younger adult, some evidence shows that even moderate alcohol use may cause more harm than good. You can take other steps to benefit your cardiovascular health besides drinking — eating a healthy diet and exercising, for example. When to avoid alcohol use In certain situations, the risks of alcohol use may outweigh the possible health benefits. For example, use alcohol only with great care and after consulting your doctor if: You're pregnant or trying to become pregnant You've been diagnosed with alcoholism or alcohol abuse, or you have a strong family history of alcoholism You have liver or pancreatic disease You have heart failure or you've been told you have a weak heart You take prescription or over-the-counter medications that can interact with alcohol You've had a hemorrhagic stroke (when a blood vessel in your brain leaks or ruptures) Keep in mind that even moderate use isn't risk-free. For example, drinking and driving is never a good idea. The risks of heavy alcohol use Heavy drinking is defined as more than three drinks on any day or more than seven drinks a week for women and for men older than age 65, and more than four drinks on any day or more than 14 drinks a week for men age 65 and younger. Binge drinking is defined as four or more drinks within two hours for women and five or more drinks within two hours for men. While moderate alcohol use may offer some health benefits, heavy drinking — including binge drinking — has no health benefits. Excessive drinking can increase your risk of serious health problems, including: Certain cancers, including breast cancer and cancers of the mouth, pharynx, larynx and esophagus Pancreatitis Sudden death if you already have cardiovascular disease Heart muscle damage (alcoholic cardiomyopathy) leading to heart failure Stroke High blood pressure Liver disease Suicide Accidental serious injury or death Brain damage and other problems in an unborn child Alcohol withdrawal syndrome Drink alcohol only in moderation — or not at all The latest dietary guidelines make it clear that no one should begin drinking or drink more frequently on the basis of potential health benefits. So don't feel pressured to drink alcohol. But if you do drink alcohol and you're healthy, there's probably no need to stop as long as you drink responsibly and in moderation.

Video games can power up from merely fun to meaningful experiences

 

It may be game over for critics who claim that video games are nothing more than a fun diversion. A team of researchers suggests that many games can be meaningful entertainment experiences for players. In a study of people's experiences with video games, players indicated that they not only enjoyed playing games, but that they also frequently appreciated them at a deeper, more meaningful level. These findings should be encouraging to video game developers who want to invest in producing games that examine more meaningful, poignant or contemplative topics. "Video games are often stereotyped as something that is just fun and entertaining, but not something that is deeply appreciated," said Mary Beth Oliver, Distinguished Professor in Media Studies and co-director of Media Effects Research Laboratory, Penn State. "Video games do not seem to have the same critical acclaim as, for example, books and plays or even music." Participants in the study suggested that story details in the game were critical to feelings of appreciation. They also indicated that more meaningful games were associated with heightened feelings of insight or enrichment. "That insight could be anything from an emotion or virtue -- like courage -- to an insight on human spirituality," said Oliver. The researchers, who report their findings in the current issue of Psychology of Popular Media Culture, said games may hold promise of providing players with enriching or gratifying experiences. "It's certainly true that there are some games that are silly or shallow, but that's the case for almost all forms of entertainment," said Oliver. "Our research suggests that contrary to stereotypes, games have the potential to be as meaningful to players as other, more esteemed forms of entertainment such as literature or cinema." Games may also provide players the opportunity to experience valuable situations and emotions that other forms of entertainment may not do as frequently, Oliver added. "Whereas viewers and readers typically watch characters make decisions in movies and books, many video games allow the player to actually make those choices, resulting in feelings such as guilt or pride," she added. Creating games with more interactive and more meaningful story lines is a challenge for developers, but could be worth the investment, the researchers indicate. The increased focus on narrative and emotions is a natural evolution in video games, said Nick Bowman, assistant professor of communication studies and a research associate, West Virginia University, who worked with Oliver. "The earliest video games really had very little in common with other forms of narrative entertainment," said Bowman. "Games have grown from simple point-and-click twitch games to incredibly engrossing emotional experiences and games now have the potential to give us the same sorts of feelings that great novels and music do." For example, Bowman said at one point in the game Spec Ops, the player is faced with the moral decision to use chemical weapons on an enemy. One consequence of choosing to do so is that innocent refugees are victims of the attack. The player is forced to witness the results of his or her actions, triggering a mix of emotions. "Such an experience gives players a space to challenge how they see the world, just as movies like Schindler's List or novels like Animal Farm, did for past audiences," said Bowman. "Video games have grown up." In the study, 512 video game players were assigned to one of two random groups and asked to recall games that were particularly fun or particularly meaningful. They then rated their perceptions about the game. While participants reported that they found both types were fun to play, they said they had more appreciation for the more meaningful games they played.

Teachers more likely to label black students as troublemakers

 

Teachers are likely to interpret students' misbehavior differently depending on the student's race, according to new research findings published in Psychological Science, a journal of the Association for Psychological Science. Racial differences in school discipline are widely known, and black students across the United States are more than three times as likely as their white peers to be suspended or expelled, according to Stanford researchers. Yet the psychological processes that contribute to those differences have not been clear -- until now. "The fact that black children are disproportionately disciplined in school is beyond dispute," said Stanford psychology Professor Jennifer Eberhardt in an interview. "What is less clear is why." Eberhardt and Stanford psychology graduate student Jason Okonofua examined the psychological processes involved when teachers discipline black students more harshly than white students. In the studies, real-world primary and secondary school teachers were presented with school records describing two instances of misbehavior by a student. In one study, after reading about each infraction, the teachers were asked about their perception of its severity, about how irritated they would feel by the student's misbehavior, about how severely the student should be punished, and about whether they viewed the student as a troublemaker. A second study followed the same protocol and asked teachers whether they thought the misbehavior was part of a pattern and whether they could imagine themselves suspending the student in the future. The researchers randomly assigned names to the files, suggesting in some cases that the student was black (with a name such as DeShawn or Darnell) and in other cases that the student was white (with a name such as Greg or Jake). Across both studies, the researchers found that racial stereotypes shaped teachers' responses not after the first infraction but rather after the second. Teachers felt more troubled by a second infraction they believed was committed by a black student rather than by a white student. In fact, the stereotype of black students as "troublemakers" led teachers to want to discipline black students more harshly than white students after two infractions, Eberhardt and Okonofua said. They were more likely to see the misbehavior as part of a pattern, and to imagine themselves suspending that student in the future. "We see that stereotypes not only can be used to allow people to interpret a specific behavior in isolation, but also stereotypes can heighten our sensitivity to behavioral patterns across time. This pattern sensitivity is especially relevant in the schooling context," Eberhardt said. These results have implications beyond the school setting as well. As Okonofua said, "Most social relationships entail repeated encounters. Interactions between police officers and civilians, between employers and employees, between prison guards and prisoners all may be subject to the sort of stereotype escalation effect we have identified in our research." Both Okonofua and Eberhardt suggested that useful interventions with teachers would help them to view student behavior as malleable rather than as a reflection of a fixed disposition, such as that of troublemaker. While racial disparities can be lessened by psychological interventions that help improve black students' behaviors in class, it is also important to understand how that behavior is interpreted by teachers and school authorities, Okonofua said.

New potential cause for Alzheimer's: Arginine deprivation caused by overconsumption by immune cells

 

A new Duke University study in mice suggests that in Alzheimer's disease, certain immune cells that normally protect the brain begin to abnormally consume an important nutrient: arginine. Blocking this process with a small-molecule drug prevented the characteristic brain plaques and memory loss in a mouse model of the disease.

Published April 15 in the Journal of Neuroscience, the new research not only points to a new potential cause of Alzheimer's but also may eventually lead to a new treatment strategy.

"If indeed arginine consumption is so important to the disease process, maybe we could block it and reverse the disease," said senior author Carol Colton, professor of neurology at the Duke University School of Medicine, and a member of the Duke Institute for Brain Sciences.

The brains of people with Alzheimer's disease show two hallmarks -- 'plaques' and 'tangles' -- that researchers have puzzled over for some time. Plaques are the build up of sticky proteins called beta amyloid, and tangles are twisted strands of a protein called tau.

In the study, the scientists used a type of mouse, called CVN-AD, that they had created several years ago by swapping out a handful of important genes to make the animal's immune system more similar to a human's.

Compared with other mice used in Alzheimer's research, the CVN-AD mouse has it all: plaques and tangles, behavior changes, and neuron loss.

In addition, the gradual onset of these symptoms in the CVN-AD mouse gave researchers a chance to study its brain over time and to focus on how the disease begins, said the study's first author Matthew Kan, an MD/PhD student in Colton's lab.

Looking for immune abnormalities throughout the lifespan of the mice, the group found that most immune system components stayed the same in number, but a type of brain-resident immune cells called microglia that are known first responders to infection begin to divide and change early in the disease.

The microglia express a molecule, CD11c, on their surface. Isolating these cells and analyzing their patterns of gene activity, the scientists found heightened expression of genes associated with suppression of the immune system. They also found dampened expression of genes that work to ramp up the immune system.

"It's surprising, because [suppression of the immune system is] not what the field has been thinking is happening in AD," Kan said. Instead, scientists have previously assumed that the brain releases molecules involved in ramping up the immune system, that supposedly damage the brain.

The group did find CD11c microglia and arginase, an enzyme that breaks down arginine, are highly expressed in regions of the brain involved in memory, in the same regions where neurons had died.

Blocking arginase using the small drug difluoromethylornithine (DFMO) before the start of symptoms in the mice, the scientists saw fewer CD11c microglia and plaques develop in their brains. These mice performed better on memory tests.

"All of this suggests to us that if you can block this local process of amino acid deprivation, then you can protect -- the mouse, at least -- from Alzheimer's disease," Kan said.

DFMO is being investigated in human clinical trials to treat some types of cancer, but it hasn't been tested as a potential therapy for Alzheimer's. In the new study, Colton's group administered it before the onset of symptoms; now they are investigating whether DFMO can treat features of Alzheimer's after they appear.

Does the study suggest that people should eat more arginine or take dietary supplements? The answer is 'no,' Colton said, partly because a dense mesh of cells and blood vessels called the blood-brain barrier determines how much arginine will enter the brain. Eating more arginine may not help more get into the sites of the brain that need it. Besides, if the scientists' theory is correct, then the enzyme arginase, unless it's blocked, would still break down the arginine.

"We see this study opening the doors to thinking about Alzheimer's in a completely different way, to break the stalemate of ideas in AD," Colton said. "The field has been driven by amyloid for the past 15, 20 years and we have to look at other things because we still do not understand the mechanism of disease or how to develop effective therapeutics."