Knowledge Update

London, June 12 (IANS) An analysis of microscopic aquatic creatures called planktonic foraminifera, whose fossil remains now resemble miniaturised popcorn, has provided the first statistical evidence that the number of species that can exist on the Earth depends on how the environment changes.

"While the idea of infinite species on a finite Earth is clearly fanciful, the relevance of upper limits to diversity is still a fractious debate amongst evolutionary biologists, ecologists and palaeontologists," said study lead author Thomas Ezard from the University of Southampton.

"We are the first to show statistically that this upper limit is environmentally dependent. It's intuitive that a changing environment alters how many species we see -- the spatial gradient of more species in the tropics than at the poles is pervasive evidence for its large-scale impact," Ezard added.

While previous research typically focused individually on either biological, climate change or geological explanations, this new study -- published recently in the journal Ecology Letters -- examined the co-dependence of these factors on how species interact.

Looking at the fossil history of 210 evolutionary species of macroperforate planktonic foraminifera in the Cenozoic Era from 65 million years ago to the present, the researchers found that the number of species was almost certainly controlled by competition among themselves and probably kept within a finite upper limit.

"We used mathematical models to reveal how environmental changes influence both the rate of diversification among species and how many species can co-exist at once. Our results suggest that the world is full of species, but that the precise fullness varies through time as environmental changes alter the outcome of competition among species," Ezard said. ​

​London, June 8 (IANS) An experiment by the European Space Agency (ESA) has passed a series of crucial tests with flying colours -- paving the way for gravitational wave observatory scheduled for launch in 2034.

A crucial component of the experiment is a two-kg cube made up of a high-purity gold and platinum alloy, which is currently sailing through space almost completely free of any force other than gravity. 

The project has proved in principle that a formation of such cubes flown in space will be able to function as a space-based gravitational wave observatory, which will be able to detect signals from supermassive black hole collisions and other violent events that would be impossible to see on Earth. 

Details of the experiment -- Laser Interferometer Space Antenna (LISA) Pathfinder mission -- was recently published in the journal Physical Review Letters. 

The free-falling test mass, as the gold and platinum cube is known, is nestled inside the shell-like LISA Pathfinder spacecraft, and has been orbiting a location in space called Lagrangian Point 1 (L1) since February 2016. 

At L1, the gravitational pull of the Earth and Sun are such that objects near the point execute orbits around L1 in much the same way that a satellite orbits the Earth.

The LISA Pathfinder mission is a crucial test of systems that will be incorporated in three spacecraft that will comprise the Laser Interferometer Space Antenna (LISA) gravitational wave observatory scheduled to commence in 2034. 

Each LISA spacecraft will contain two test masses like the one currently in the LISA Pathfinder spacecraft. The LISA Pathfinder mission's extraordinary success is a crucial step on the way to launching the LISA observatory.​

​New York, June 10 (IANS) Clouds or haze enveloping the atmosphere of exoplanets, including "hot Jupiters", could be preventing a substantial amount of water from being detected by space telescopes, says a study led by an Indian-origin scientist.

Astronomers have found many hot Jupiters -- whose mass are similar to that of Jupiter but are much closer to their parent star than Jupiter is to the Sun -- with water in their atmosphere, but others appear to have none.

"The motivation of our study was to see what these planets would be like if they were grouped together, and to see whether they share any atmospheric properties," said lead author Aishwarya Iyer from NASA's Jet Propulsion Laboratory-Pasadena, California.

"Clouds or haze seem to be on almost every planet we studied," Iyer said. "You have to be careful to take clouds or haze into account, or else you could underestimate the amount of water in an exoplanet's atmosphere by a factor of two," he added.

The clouds themselves are likely not made of water, as the planets taken into account can reach a scorching 1,100 degrees Celsius, meaning any water they host would take the form of water vapour.

In the study, published recently in the Astrophysical Journal, scientists looked at a set of 19 hot Jupiters previously observed by Hubble. The telescope's Wide Field Camera 3 had detected water vapor in the atmospheres of 10 of these planets, and no water on the other nine. 

But that information was spread across more than a dozen studies. The methods of analysing and interpretation varied because the studies were conducted separately. There had not been one overarching analysis of all these planets.

Iyer's team combined the datasets for all 19 hot Jupiters to create an average overall light spectrum for the group of planets. They then compared these data to models of clear, cloud-free atmospheres and those with various cloud thicknesses.

The scientists determined that, for almost every planet they studied, haze or clouds were blocking half of the atmosphere, on average.

"In some of these planets, you can see water peeking its head up above the clouds or haze, and there could still be more water below," Iyer said.

Scientists do not yet know the nature of these clouds or hazes, including what they are they made of.​

​London, June 11 (IANS) The Hubble Space Telescope has uncovered a mysterious solitary dwarf galaxy - a type that is smaller and messier than its cosmic cousins, lacking the majestic swirl of a spiral or the coherence of an elliptical.

This galaxy is known as UGC 4879. There are about 2.3 million light years between UGC 4879 and its closest neighbor, Leo A, which is about the same distance as that between the Andromeda Galaxy and the Milky Way, the European Space Agency said in a statement.

Launched in 1990, the Hubble Space Telescope (HST) is a project of international cooperation between NASA and the European Space Agency.

This galaxyÂ’s isolation means that it has not interacted with any surrounding galaxies, making it an ideal laboratory for studying star formation uncomplicated by interactions with other galaxies, the statement added.

Studies of UGC 4879 have revealed a significant amount of star formation in the first four billion years after the Big Bang, followed by a strange nine-billion-year lull in star formation that ended one billion years ago by a more recent re-ignition. 

The reason for this behaviour, however, remains mysterious, and the solitary galaxy continues to provide ample study material for astronomers looking to understand the complex mysteries of star birth throughout the universe.​

​London, June 11 (IANS) Human and non-human primates can learn an astonishing variety of novel behaviours that could not have been directly anticipated by evolution. This ability to cope with new situations is due to the "pre-adapted" nature of the primate brain, says a study.

The brain anticipates all of the new situations that it may encounter in a lifetime by creating a special kind of neural network, the study said.

The findings appeared in the journal PLOS Computational Biology.

For the study, researchers from French National Institute of Health and Medical Research (Inserm) investigated one of the most noteworthy properties of primate behavior, its diversity and adaptability. 

This study showed that our seemingly miraculous pre-adaptation comes from connections between neurons that form recurrent loops where inputs can rebound and mix in the network, like waves in a pond, thus called "reservoir" computing. 

This mix of the inputs allows a potentially universal representation of combinations of the inputs that can then be used to learn the right behaviour for a new situation.

The authors demonstrated this by training a reservoir network to perform a novel problem-solving task. 

They then compared the activity of neurons in the model with activity of neurons in the prefrontal cortex of a primate that was trained to perform the same task.

Remarkably, there were striking similarities in the activation of neurons in both the reservoir model and the primate.

The findings showed that by allowing essentially unlimited combinations of internal representations in the network of the brain, one of them is always on hand for the given situation.​

​London, June 11 (IANS) Scientists have developed a new tool to determine the inherent biological differences between individuals -- paving the way for personalised medicine tailored to the specific profile of individual patients.

Johan Auwerx of Switzerland's École polytechnique fédérale de Lausanne (EPFL) and Ruedi Aebersold of ETH Zurich, the Swiss Federal Institute of Technology, set out to overcome one of the biggest obstacles in successfully treating metabolic disorders such as diabetes, obesity and fatty liver, which depends on the variation in the way patients respond to medication.

Working with mouse models, the researchers successfully connected the variation between individuals' genomes to the variation between their proteomes -- their full set of proteins. In this way, they took a giant leap in profiling the biology of a particular individual.

"There is a black box between a patient's genome and their disease," said Auwerx, whose lab handled the genome side of the study published recently in the journal Science.

"What we have done here is find a way to fill the black box by obtaining information on the patient's proteome," he added.

The study enabled the researchers to better understand the role several proteins play when it comes to metabolising fat and producing energy from it.

"Like the mouse strains in this study, each patient with a disease is genetically different," said Aebersold. 

"The approach we used in the mouse cohort can now be applied one-for-one in research on human diseases, and particularly for personalised medicine," he added.

The researchers now aim to be able to customise medical intervention for human patients based on their individual biological makeup.​

​London, June 9 (IANS) Most of the commonly prescribed antidepressant drugs are ineffective and some may be unsafe for children and teenagers with major depression, according to a study.

"The balance of risks and benefits of antidepressants for the treatment of major depression does not seem to offer a clear advantage in children and teenagers, with probably only the exception of fluoxetine," said co-author Peng Xie from the Chongqing Medical University in China. 

Major depressive disorder is common in children and adolescents across the world, affecting around 3 per cent of children aged 6 to 12 years and about 6 per cent of teenagers aged 13 to 18 years.

"Without access to individual-level data it is difficult to get accurate effect estimates and we can't be completely confident about the accuracy of the information contained in published and unpublished trials," said study lead author Andrea Cipriani from the University of Oxford. 

Cipriani and colleagues did a systematic review and network meta-analysis of all published and unpublished randomised trials comparing the effects of 14 antidepressants in young people with major depression up to the end of May 2015, according to the study published in the journal The Lancet.

Analysis of 34 trials involving 5,260 participants (average age 9 to 18 years) showed that the benefits outweighed the risks in terms of efficacy and tolerability only for fluoxetine.

Nortriptyline was less efficacious than seven other antidepressants and placebo.

Imipramine, venlafaxine, and duloxetine had the worst profile of tolerability, leading to significantly more discontinuation than placebo. Venlafaxine was linked with an increased risk of engaging in suicidal thoughts or attempts compared with placebo and five other antidepressants. 

The researchers warned that due to the lack of reliable data, it was not possible to comprehensively assess the risk of suicidality for all drugs.

"Hundreds of thousands of people worldwide have agreed to participate in trials aiming to find better treatments for their disorders and, ultimately, help the progress of medical science," Cipriani said.

"Patients' privacy must be guaranteed by adequate policies and technological measures, but delay in implementing responsible data sharing policies has negative consequences for medical research and patient outcomes, as demonstrated by this study," he added.​

​Toronto, June 9 (IANS) A team of researchers at a Canadian university has developed an advanced 4-D technique to avoid costly delays often associated with massive public infrastructure projects.

"Any delay in the work on one segment might impact the work on another, which ultimately results in delaying the whole project and augmenting the cost," said senior study author Amin Hammad of Concordia University in Montreal. 

"The simulation methods we've developed help contractors analyse the schedule and eliminate the risks," Hammad added.

The study was recently published in the journal Automation in Construction. 

Reconstructing heavily used highways is an extremely complex process because of the need to maintain traffic flow. Therefore, a plan is usually required to gradually shift the traffic from the existing segments to the newly built ones.

The parallel coordination of construction and demolition activities with traffic flow is essential to the success of projects, according to Hammad. 

"That's why our new modelling method uses a 4-D approach -- taking into account the three normal space axes, plus time, to coordinate the traffic phasing with the demolition and construction of the old and new segments, respectively," he said.

This method is the first to integrate stochastic simulation techniques -- algorithms to predict randomness -- with 3-D modelling of highways to generate 4-D representations that can be used to detect and plan for scheduling clashes, and define the feasible sequences in which the segments of the highway bridges can be constructed or demolished.​

​Sydney, June 9 (IANS) The move from life on land to life in the sea has led to the evolution of a new sense for sea snakes, potentially making them more likely to be able to sense vibrations from all directions, an Australian study suggests.

The international team studied tiny and poorly understood structures on the heads of snakes called 'scale sensilla'. 

"Land snakes and many lizards have small raised structures on the scales on their heads -- called scale sensilla -- that they use to sense objects by direct touch," said lead author Jenna Crowe-Riddell from the University of Adelaide in Australia.

"We found that the scale sensilla of sea snakes were much more dome-shaped than the sensilla of land snakes, with the organs protruded further from the animals' scales, potentially making them more likely to be able to sense vibrations from all directions,” Crowe-Riddell noted.

The researchers also found that scale sensilla on some of the fully aquatic snakes covered a much higher proportion of the scales' surface.

"We believe sea snakes use these organs to sense objects at a distance by 'feeling' movements in the water. This hydrodynamic sense is not an option for land animals. In water, a new way of sensing the environment becomes possible," Crowe-Riddell noted.

The researchers looked at 19 species of snakes, including fully-aquatic, semi-aquatic and land species, and measured the coverage of sensilla over single scales on their heads.

They used DNA sequencing to reconstruct the evolutionary relationships between the snakes, and used microscope imaging and specially developed software to automatically detect the small organs from silicone casts of snake heads. They also examined the shape of the sensilla using scanning electron microscopy.

The research was published in the Royal Society journal Open Biology.​

​London, June 9 (IANS) Confirming a long-standing hypothesis, scientists from the Netherlands' Leiden University have shown that the genetic information in the DNA not only determines who we are, but also the DNA mechanics.

Since the mid-198080s it has been hypothesised that there is a second layer of information on top of the genetic code: DNA’s mechanical properties. 

Each of our cells contains two meters of DNA molecules, so these molecules need to be wrapped up tightly to fit inside a single cell. 

The way in which DNA is folded, determines how the letters are read out, and therefore which proteins are actually made. 

In each organ, only relevant parts of the genetic information are read, based on how the DNA is folded. 

The theory goes that mechanical cues within the DNA structures determine how DNA prefers to fold.

In a study published in the journal PLoS One, Leiden physicist Helmut Schiessel and his research group provided strong evidence that this second layer of information indeed exists. 

With their computer code they simulated the folding of DNA strands with randomly assigned mechanical cues. 

It turns out that these cues indeed determine how the DNA molecule is folded into so-called nucleosomes. 

Schiessel found correlations between the mechanics and the actual folding structure in the genome of two organisms ? baker’s yeast and fission yeast. 

With this finding we know that evolutionary changes in DNA ? mutations ? can have two very different effects.

The letter sequence encoding for a specific protein can change or the mechanics of the DNA structure can change, resulting in a different packaging and accessibility of the DNA and therefore a different frequency of production of that protein.​