BackFive latest scientific and technological developments that matter
Every week, 'Mint' will identify 5 scientific and technological developments that promise to change the world around you
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Are you ill? Your tweets may soon tell
Public health workers are studying trends on social media in the hope that they will be able to monitor tweets to quickly identify a rise of influenza, depression or other health issues in a specific area, according to research at the Department of Energy’s Pacific Northwest National Laboratory (PNNL).
The researchers uncovered the expression of opinion and emotion as a potential signal on Twitter, as reported in the journal European Physical Journal (EPJ) Data Science. “Opinions and emotions are present in every tweet, regardless of whether the user is talking about their health," said Svitlana Volkova, a data scientist at PNNL and lead author of the study in a 14 August press statement. “Like a digital heartbeat, we’re finding how changes in this behaviour relate to health trends in a community."
But can tweets replace a health exam for detecting a rise in the flu or other health threats? Volkova’s research suggests so. The research team studied 171 million tweets from users associated with the US military to determine if the opinions and emotions they express reflect visits to the doctor for influenza-like illnesses. They compared military and civilian users from 25 US and six international locations to see if this pattern varies based on location or military affiliation.
For privacy, the tweets used in this study were anonymized. The goal of the research is to discover generalized public health trends, not diagnose the health status of individual users. Overall, they found how people behave significantly varies by location and group. For example, tweets from military populations tend to contain more negative and less positive opinions, as well as increased emotions of sadness, fear, disgust and anger. This trend is true regardless of health.
They identified a general trend: Neutral opinions and sadness were expressed most during high influenza-like illness periods. During low illness periods, positive opinion, anger and surprise were expressed more.
The research team will now study whether these behaviours can be used to predict a change in health trends before they happen. If this method works in real time, public health workers could look into the future by asking “How are your tweets feeling?"
Urban floods intensifying, countryside drying up
A global analysis of the world’s river systems, based on data collected from more than 43,000 rainfall stations and 5,300 river monitoring sites across 160 countries, reveals signs of a radical shift in stream-flow patterns. It shows more intense flooding in cities and smaller catchments coupled with a drier countryside. The study by engineers at University of New South Wales in Sydney, which will appear in the latest issue of the journal Scientific Reports according to a 14 August release, explored how rising local temperatures due to climate change might be affecting river flows.
The study found that warmer temperatures lead to more intense storms, which was expected since a warming atmosphere means warmer air, and warmer air can store more moisture. So when the rains do come, they are more intense. But the researchers were puzzled over why flooding is not increasing at the same rate as the higher rainfall.
The answer turned out to be the other facet of rising temperatures—more evaporation from moist soils is causing them to become drier before any new rain occurs. Meanwhile, in -small catchments and urban areas, where there are limited expanses of soil to capture and retain moisture, the same intense downpours become equally intense floods, overwhelming stormwater infrastructure and disrupting life, the researchers noted.
Global flood damage cost more than US$50 billion in 2013; this is expected to more than double in the next 20 years as extreme storms and rainfall intensify and growing numbers of people move into urban centres. Meanwhile, global population over the next 20 years is forecast to rise another 23% from today’s 7.3 billion to 9 billion -- requiring added productivity and hence greater water security. The reduction in flows noted by this study makes this an even bigger challenge than before, the researchers caution.
Towards automating fingerprint analysis
Criminals typically leave behind fingerprints at the crime scene. Forensics helps investigators analyse these fingerprints. However, fingerprints left at a crime scene are often partial, distorted and smudged. Also, if the print is left on something with a confusing background pattern such as a note, it may be difficult to separate the print from the background.
Scientists from the National Institute of Standards and Technology (NIST) and Michigan State University report that they have developed an algorithm that automates a key step in the fingerprint analysis process. Their research was published in IEEE Transactions on Information Forensics and Security this week. The idea was to reduce the human subjectivity to make fingerprint analysis more reliable and more efficient.
The researchers used machine learning to build their algorithm. Unlike traditional programming in which you write out explicit instructions for a computer to follow, in machine learning, you train the computer to recognize patterns by showing it examples. After training was complete, researchers tested the performance of the algorithm by having it score a new series of latent prints. They then submitted those scored prints to the Automated Fingerprint Identification System (AFIS) software connected to a database of over 250,000 rolled prints.
In this test, the researchers knew the correct match for each latent print. The scoring algorithm performed slightly better than the average of the human examiners involved in the study. What made this breakthrough possible, beside recent advances in machine learning and computer vision, was the availability of a large dataset of latent prints. In this case, the Michigan State Police provided the researchers with the testing dataset, after having first stripped the data of all identifying information due to privacy concerns.
The next step for the researchers is to use an even larger dataset. This will allow them to improve the algorithm’s performance and more accurately measure its error rate.
Why your brain believes expensive wine tastes better
You may truly believe that the more expensive the wine, the better the taste. However, neuroscientists have periodically pointed out that the phenomenon that identical products are perceived differently due to differences in price is called the “marketing placebo effect".
Previous work from INSEAD Associate Professor of Marketing Hilke Plassmann’s research group did show that a higher price increased the expectation that the product (be it chocolate or wine) will also taste better and in turn affects taste processing regions in the brain. Similarly, researchers at Stanford and Caltech demonstrated that people’s brains experience more pleasure when they think they are drinking a $45 wine instead of a $5 bottle—even when it’s the same stuff.
University of Bonn researchers have now assessed how different prices get translated into corresponding taste experiences in the brain, even if the wine tasted does not differ. “It has so far been unclear how the price information ultimately causes more expensive wine to also be perceived as having a better taste in the brain," said Prof. Bernd Weber, Acting Director of the Center for Economics and Neuroscience (CENs) at the University of Bonn, in a 14 August press statement.
The wine tasting took place lying down in a magnetic resonance imaging (MRI) scanner, allowing brain activity to be recorded “online" while participants were tasting the wines. The participants were first shown the price of the wine, following which they were administered only around a milliliter of the respective wine through a tube in their mouths. The participants were then asked to rate the wine on a nine-point scale via a button. Their mouths were then rinsed with a neutral liquid and the next identical wine sample was given for tasting. All of the experiments were performed in the brain scanner at the Life & Brain Center at the University of Bonn.
The research team discovered that above all parts of the medial pre-frontal cortex and also the ventral striatum were activated more when prices were higher. While the medial pre-frontal cortex particularly appears to be involved in integrating the price comparison and thus the expectation into the evaluation of the wine, the ventral striatum forms part of the brain’s reward and motivation system.
“Ultimately, the reward and motivation system plays a trick on us," explains INSEAD post-doctoral fellow Liane Schmidt. When prices are higher, it leads us to believe that a taste is present that is not only driven by the wine itself, because the products were objectively identical in all of the tastings. “The exciting question is now whether it is possible to train the reward system to make it less receptive to such placebo marketing effects," says Prof. Weber.
Bacteria too can feel their surroundings
University of Colorado, Boulder scientists have discovered that individual bacteria, too, can feel their external environment. And it is similar to how humans do; our sense of touch is relayed to the brain via small electrical pulses. The researchers demonstrated that E. coli bacteria cells get excited when poked, sending out voltage induced calcium ion signals—the same way a vertebrate’s sensory nervous system works. The findings, which could advance fundamental bacteria research and may eventually aid drug development for infectious diseases, were published on 14 August in the journal Proceedings of the National Academy of Sciences.
The study also sheds new light on bacterial activity with regard to infection. For example, when exposed to antibiotics, a few bacteria cells with unique electric signals usually survive. These survivors then go on to reproduce and share their drug-resistant capabilities with other bacteria, eventually rendering the antibiotic useless. The researchers believe that if they block bacterial electrical activity, the bacteria may be less likely to infect. It is akin to cutting their hands off so they can no longer feel.
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