Knowledge Update

​Singapore, March 1 (IANS) Using nearly 100,000 images extracted from Google Street View, a team of researchers has developed a method to map and quantify how street trees regulate ecosystem services.

London, March 1 (IANS) Frogs have the unique ability to see colour even when it is so dark that we are not able to see anything at all, new research has found.

The findings, published in the journal Philosophical Transactions of the Royal Society B, suggest that the night vision of frogs and toads may be superior to that of all other animals. 

"It's amazing that these animals can actually see colour in extreme darkness, down to the absolute threshold of the visual system. These results were unexpected," said one of the study authors Almut Kelber, Professor at Lund University in Sweden.

Most vertebrates, including humans, have two types of visual cells located in the retina, namely cones and rods. 

The cones enable us to see colour, but they usually require a lot of light and, therefore, stop working when it gets dark, in which case the rods take over so that we can at least find our way home, although in black and white.

In toads and frogs, the rods are a bit special. 

It was previously known that toads and frogs are unique in having rods with two different sensitivities. 

This has not been found in other vertebrates, and it is also the reason why researchers have long suspected that frogs and toads might be able to see colour also in low-light conditions.

The new study proves this to be true, and the results exceeded all expectations.

The researchers studied to what extent frogs and toads use their colour vision when searching for a mate or hunting for food. 

The results showed that the animals stop using their colour information fairly early when it comes to finding someone with whom to mate, whereas they continue to take advantage of their colour vision to select food in such low-light conditions that humans lose their ability to see colour.

"We have previously shown moths and geckos are also able to see colour in inferior light conditions compared to humans. However, frogs apparently have a unique ability to see colour in the dark," Kelber said.

New York, March 1 (IANS) Researchers have identified 35 mosquito species, including 26 previously unsuspected ones, that could possibly transmit the deadly Zika virus.

"The biggest take-home message is that these are the species that we need to prioritise," said lead author Michelle Evans from University of Georgia in the US. 

Zika virus is currently known to be transmitted to people primarily through the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus). 

These are the same mosquitoes that spread dengue and chikungunya viruses, according to US Centers for Disease Control and Prevention.

The researchers said that targetting Zika's potential vectors -- species that can transmit the virus from one host to another -- is an urgent need, given its explosive spread and the devastating health effects associated with it.

The new predictive model, detailed in the journal eLife, could streamline the initial step of pinpointing Zika vectors.

"What we've done is to draw up a list of potential vector candidates based on the associations with viruses that they've had in the past as well as other traits that are specific to that species," study co-author Courtney Murdock, Assistant Professor at University of Georgia, said.

"That allows us to have a predictive framework to effectively get a list of candidate species without having to search blindly," Murdock said.

The researchers developed their model using machine learning, a form of artificial intelligence that is particularly useful for finding patterns in large, complicated data sets. 

Data used in the model consisted of information about the traits of flaviviruses -- the family that includes Zika, yellow fever and dengue -- and all the mosquito species that have ever been associated with them.

​Washington, March 1 (IANS) A trip past the sun may have selectively altered the production of one form of water in a comet known as Lovejoy -- an effect not seen by astronomers before, a new NASA study suggests.

The findings could shed new light on how much comets might have contributed to Earth's water compared to asteroids.

"Comets can be quite active and sometimes quite dynamic, especially when they are in the inner solar system, closer to the sun," said co-author of the study Michael Mumma, Director of NASA's Goddard Center for Astrobiology. 

NASA scientists observed the Oort cloud comet C/2014 Q2, also called Lovejoy, when it passed near Earth in early 2015. 

Through NASA's partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed the comet at infrared wavelengths a few days after Lovejoy passed its perihelion - or closest point to the sun.

The team focused on Lovejoy's water, simultaneously measuring the release of H2O along with production of a heavier form of water, HDO. 

Water molecules consist of two hydrogen atoms and one oxygen atom. A hydrogen atom has one proton, but when it also includes a neutron, that heavier hydrogen isotope is called deuterium, or the "D" in HDO. 

From these measurements, the researchers calculated the D-to-H ratio -- a chemical fingerprint that provides clues about exactly where comets (or asteroids) formed within the cloud of material that surrounded the young sun in the early days of the solar system.

Researchers also use the D-to-H value to try to understand how much of Earth's water may have come from comets versus asteroids.

The scientists compared their findings from the Keck observations with another team's observations made before the comet reached perihelion, using both space- and ground-based telescopes, and found an unexpected difference.

After perihelion, the output of HDO was two to three times higher, while the output of H2O remained essentially constant, showed the findings published online in the Astrophysical Journal Letters.

This meant that the D-to-H ratio was two to three times higher than the values reported earlier.

"If the D-to-H value changes with time, it would be misleading to assume that comets contributed only a small fraction of Earth's water compared to asteroids," lead author of the study Lucas Paganini, a researcher with the Goddard Center for Astrobiology, said.

​Kuala Lumpur, Feb 28 (IANS) The oil company Saudi Aramco will invest seven billion dollars in a refinery and petrochemical development project in Malaysia following a deal with Malaysia's Petronas, media reports said on Tuesday.

​Manila, Feb 28 (IANS) Developing economies of Asia and the Pacific region will need infrastructure investments worth $26 trillion from now until 2030, according to an Asian Development Bank (ADB) report issued on Tuesday.

​New York, Feb 28 (IANS) Researchers have developed a computer method called ZeitZeiger that uses a sample of human blood to accurately predict circadian time -- the time of day according to a person's body clock.

Barcelona, Feb 28 (IANS) With the aim to provide great video quality while using less bandwidth, global video streaming service Netflix will soon support HDR technology on mobile devices.

New York, Feb 28 (IANS) A sedentary lifestyle can take a huge toll on your heart. Researchers have found that lack of exercise and excessive weight are strongly associated with a type of heart failure that is very hard to treat. Heart failure is a chronic condition in which the heart is unable to supply enough oxygenated blood to meet the demands of the body. "Previous studies have consistently found an association between low levels of physical activity, high BMI (body mass index), and overall risk of heart failure, but this study shows that the association is more pronounced for heart failure with preserved ejection fraction, the type of heart failure that is the most challenging to treat," said the study's senior author Jarett Berry, Associate Professor at University of Texas Southwestern Medical Center in the US. Heart failure is approximately equally divided between two subtypes -- heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HfrEF). Ejection fraction refers to the percentage of the blood that exits the heart with each contraction. Many treatments have been developed for treating heart failure with reduced ejection fraction but there are no evidence-based treatments for the other type. The pooled analysis looked at data from 51,000 participants in three cohort studies, the Women's Health Initiative, the Multiethnic Study of Atherosclerosis (MESA), and the Cardiovascular Health Study. Among the 51,000 participants, there were 3,180 individuals who developed heart failure. Of these, 39 per cent were heart failure with preserved ejection fraction, 29 per cent were heart failure with reduced ejection fraction, and 32 per cent had not been classified when the data was gathered. The incidence of heart failure with preserved ejection fraction was 19 per cent lower for individuals who exercised at recommended levels, showed the findings published in the Journal of the American College of Cardiology. Similarly, body mass index (BMI) had an inverse relationship with heart failure with preserved ejection fraction. Higher BMI levels were more strongly associated with heart failure with preserved ejection fraction than with heart failure with reduced ejection fraction.

​New York, Feb 28 (IANS) An increasing number of teenagers get discouraged to talk to their parents about potentially risky online experiences, such as cyberbullying, sexual exchanges and viewing inappropriate content online, because parents tend to emote much stronger feelings and tend to freak out, become angry or scared, researchers have found. The study showed that parents and children often have much different perceptions of and reactions to the same online situations. "There seems to be a disconnect between what types of situations teenagers experience every day and what types of experiences parents have online," said Pamela Wisniewski, Assistant Professor at the University of Central Florida in the US. "Teenagers tended to be more nonchalant and say that the incident made them embarrassed, while parents, even though they were reporting more low-risk events, emoted much stronger feelings, becoming angry and scared. "For teenagers, some felt these types of experiences were just par for the course," Wisniewski added, in the study, presented at the ACM Conference on Computer-Supported Cooperative Work and Social Computing in Oregon. Parents who overreact, when their children report any such events, are likely to curb communication as when risky situation are reported to parents, they tend to freak out and make things worse, causing teenagers to refrain from talking about situations that may upset their parents. "When teenagers actually talked to their parents about what had happened, they often wanted help understanding or navigating the situation, but parents tended to misinterpret their intent, not realising that their teenagers were trying to open lines of communication," Wisniewski said. Parental reactions -- both over or under reactions -- may not just thwart teenagers from seeking their parents' help with a current problem, but also diminish the teenagers' ability to successfully navigate future online encounters that may be even more risky, the researchers revealed.