Science & Technology


Marine animals use new form of secret light communication

© Yakir Gagnon/QBI
This image shows a mantis shrimp in a defensive position, on its back with its legs, head and heavily armored tail closed over. The red color indicates areas of reflected circular polarizing light.
Researchers from the Queensland Brain Institute at The University of Queensland have uncovered a new form of secret light communication used by marine animals.

The findings may have applications in satellite remote sensing, biomedical imaging, cancer detection, and computer data storage.

Dr Yakir Gagnon, Professor Justin Marshall and colleagues previously showed that mantis shrimp (Gonodactylaceus falcatus) can reflect and detect circular polarising light, an ability extremely rare in nature. Until now, no-one has known what they use it for.

The new study shows the shrimp use circular polarisation as a means to covertly advertise their presence to aggressive competitors.


Ghostly and beautiful: "Planetary nebulae" get more meaningful physical presence

© ESA/Hubble & NASA, ESO, Ivan Bojicic, David Frew, Quentin Parker
A collage showing 22 individual planetary nebulae artistically arranged in approximate order of physical size. The scale bar represents 4 light years. Each nebula's size is calculated from the authors' new distance scale, which is applicable to all nebulae across all shapes, sizes and brightnesses. The very largest planetary nebula currently known is nearly 20 light years in diameter, and would cover the entire image at this scale.
A way of estimating more accurate distances to the thousands of so-called planetary nebulae dispersed across our Galaxy has been announced by a team of three astronomers based at the University of Hong Kong: Dr David Frew, Prof Quentin Parker and Dr Ivan Bojicic. The scientists publish their results in Monthly Notices of the Royal Astronomical Society.

Despite their name, planetary nebulae have nothing to do with planets. They were described as such by early astronomers whose telescopes showed them as glowing disc-like objects.

We now know that planetary nebulae are actually the final stage of activity of stars like our Sun. When they reach the end of their lives, these stars eject most of their atmosphere into space, leaving behind a hot dense core. Light from this core causes the expanding cloud of gas to glow in different colours as it slowly grows, fading away over tens of thousands of years.

There are thousands of planetary nebulae in our Galaxy alone, and they provide targets for professional and amateur astronomers alike, with the latter often taking spectacular images of these beautiful objects. But despite intense study, scientists have struggled to measure one of their key properties -- their distance.

People 2

Reducing intergroup conflict through contact

The world is a diverse place containing people of different races, ethnicities, and nationalities. This diversity, although beneficial in many ways, can also lead to tensions resulting in conflict between groups. Such strife occurs at every level of society, and the negative social and political outcomes it produces have led researchers to investigate ways to reduce conflict and prejudice. In a 2015 study published in the European Journal of Social Psychology, researchers Gunnar Lemmer and Ulrich Wagner (Philipps-University Marburg, Germany) examined the effectiveness of intergroup contact at reducing ethnic prejudice.

The intergroup contact theory is based on the idea that interactions between members of different groups help improve intergroup attitudes and reduce intergroup tensions and prejudice. Lab-based and real-world studies have examined the impact of different types of interactions — including face-to-face contact, indirect forms of contact, and virtual contact — at reducing prejudice between different ethnic groups. Researchers also have studied the efficacy of this type of intervention in minority- and majority-group members, as well as in regions where serious pre-existing or historical conflict exists.


Never before seen giant ice cloud on Titan

© NASA/JPL-Caltech/Space Science Institute
As winter sets in at Titan's south pole, a cloud system called the south polar vortex (small, bright "button") has been forming, as seen in this 2013 image.
NASA's Cassini spacecraft has detected a massive, never-before-seen icy cloud at the south pole of Saturn's huge moon Titan.

The newly spotted feature — part of a cloud system known as the south polar vortex — suggests that winter in the southern hemisphere of Titan will be even colder than predicted, scientists said.

The atmospheric signal "looks pretty normal, then BOOM!, increases," indicating the presence of a brand-new cloud, said Cassini participating scientist Carrie Anderson, of NASA's Goddard Space Flight Center in Greenbelt, Maryland. "I was so excited, I pretty much fell out of my chair."

Anderson presented the new Cassini results at a news briefing Nov. 11 at the 47th annual meeting of the American Astronomical Society's Division of Planetary Sciences in Oxen Hill, Maryland. She also spoke at the morning session of the conference that day.


Neuroscientists reveal how the brain can enhance connections

© adimas / Fotolia
Neuron connections. At each synapse, a presynaptic neuron sends chemical signals to one or more postsynaptic receiving cells. In most previous studies of how these connections evolve, scientists have focused on the role of the postsynaptic neurons. However, an MIT team has found that presynaptic neurons also influence connection strength.
When the brain forms memories or learns a new task, it encodes the new information by tuning connections between neurons. MIT neuroscientists have discovered a novel mechanism that contributes to the strengthening of these connections, also called synapses.

At each synapse, a presynaptic neuron sends chemical signals to one or more postsynaptic receiving cells. In most previous studies of how these connections evolve, scientists have focused on the role of the postsynaptic neurons. However, the MIT team has found that presynaptic neurons also influence connection strength.

"This mechanism that we've uncovered on the presynaptic side adds to a toolkit that we have for understanding how synapses can change," says Troy Littleton, a professor in the departments of Biology and Brain and Cognitive Sciences at MIT, a member of MIT's Picower Institute for Learning and Memory, and the senior author of the study, which appears in the Nov. 18 issue of Neuron.


Our closest wormy cousins: About 70% of our genes trace their ancestry back to the acorn worm

© Andrew Gillis
This is a juvenile of Saccoglossus kowalevskii with one of the transcription factors expressed in the pharyngeal region (highlighted in blue).
Scientists have analyzed the genomes of two acorn worm species and found that approximately two-thirds of human genes have counterparts in the ancestors of these marine animals. These ancient genes, and their organization within the genome, were already in place in the common ancestor of humans and acorn worms that lived over half a billion years ago.

A team from the Okinawa Institute of Science and Technology Graduate University (OIST) and its collaborators has sequenced the genomes of two species of small water creatures called acorn worms and showed that we share more genes with them than we do with many other animals, establishing them as our distant cousins.

The study found that 8,600 families of genes are shared across deuterostomes, a large animal grouping that includes a variety of organisms, ranging from acorn worms to star fishes, from frogs to dogs, to humans. This means that approximately 70% of our genes trace their ancestry back to the original deuterostome.

By comparing the genomes of acorn worms to other animals, OIST scientists inferred the presence of these genes in the common ancestor of all deuterostomes, an extinct animal that lived half a billion years ago. This research shows that the pharyngeal gene cluster is unique to the deuterostomes and it could be linked to the development of the pharynx, the region that links the mouth and nose to the esophagus in humans. These findings were published in Nature, summarizing an international collaboration between OIST researchers and teams from the US, UK, Japan, Taiwan and Canada.


Russian break-through: Photonic radar test-launch by 2018

© © Mikhail Fomichev / RIA Novosti
Radio-photonic technology to be applied in radio astronomy, radio detection and ranging, optical fiber and mobile communications
Russia's major electronic warfare systems producer is set to test a photonic radar station within three years. It is expected to open a new era of light and precise radar electronics for systems where weight is critical, such as drones and satellites.

The radio-photonic radar system of the future will be based on active radio-optical phased array (Russian abbreviation: ROFAR) technology being developed now by Radio-Electronic Technologies Concern (KRET), an integral part of the Rostech state corporation.

"The KRET has launched radio-photonic laboratory research to create ROFAR to be integrated on next generation radar systems, which is expected to deliver breakthrough performance characteristics to radiolocation stations," Igor Nasenkov, deputy general director of KRET, told RIA Novosti during the Dubai Airshow 2015.

Work on ROFAR involves the creation of a specific laboratory complex within KRET. It will develop a universal technology to be later integrated into various next generation electronic systems. Nasenkov specified that the 4.5-year ROFAR program will be fulfilled on time, adding a full-scale specimen is expected to be test-launched "by 2018."

2 + 2 = 4

Infants with blind parents pay less attention to eyes

© midwestgal / Fotolia
Healthy baby making eye contact (stock image). Eye gaze is an important channel for communication, and human infants show an amazing ability to recognize and react to adults' gaze.

For parents of young children, there are few milestones more memorable than that first word. But people communicate an awful lot to each other without ever saying anything at all. That raises an intriguing question: how do infants learn to communicate with the people around them nonverbally, through eye contact?

Researchers reporting in the Cell Press journal Current Biology on November 19 have some new insight into this silent form of communication from an unlikely source: the sighted children of blind parents.

"Infants of blind parents allocated less attention to adults' eye gaze," says Atsushi Senju of Birkbeck, University of London. "It suggests that infants are actively learning from communicating with their parents and adjusting how best to interact with them."

Senju says it's important to note that those infants developed typical overall social communication abilities, suggesting that the patterns of difference the researchers observed were limited specifically to the babies' attention to adults' eye gaze.


Details from the inner life of a tooth

New X-ray method uses scattering to visualize nanostructures

© Schaff et al. / Nature
Representation of the orientation of collagen fibers within a tooth sample. The sample’s three-dimensional nanostructure was computed from a large number of separate images recorded by X-ray scattering CT.
Both in materials science and in biomedical research it is important to be able to view minute nanostructures, for example in carbon-fiber materials and bones. A team from the Technical University of Munich (TUM), the University of Lund, Charite hospital in Berlin and the Paul Scherrer Institute (PSI) have now developed a new computed tomography method based on the scattering, rather than on the absorption, of X-rays. The technique makes it possible for the first time to visualize nanostructures in objects measuring just a few millimeters, allowing the researchers to view the precise three-dimensional structure of collagen fibers in a piece of human tooth.

In principle, X-ray computed tomography (CT) has been around since the 1960s: X-ray images are taken of an object from various directions, and a computer then uses the individual images to generate a three-dimensional image of the object. Contrast is produced by the differential absorption of X-rays in dissimilar materials. However, the new method, which was developed by Franz Pfeiffer, professor for Biomedical Physics at TUM and his team utilizes the scattering of X-rays rather than their absorption. The results have now been published in the journal Nature.

Better Earth

New theory suggests Earth's mass extinction events caused by lack of trace minerals in world's oceans

© Sheila Terry/SPL
Are you getting enough minerals? A new theory suggests most of Earth's mass extinction events could have been caused by a lack of essential trace elements in the world's oceans, causing fatal deficiencies in marine animals, from plankton to reptiles.

Earth has been hit with five mass extinction events. The two most dramatic ones had pretty clear causes. The dinosaurs were probably wiped out 66 million years ago thanks to a massive meteor falling on modern-day Mexico, while the end-Permian extinction, which wiped out 90 per cent of species 252 million years ago, was probably the result of massive volcanoes in Siberia.

But that leaves three other mass extinctions, with no agreed cause.

"It's a complex scenario," says John Long from Flinders University in Adelaide, Australia. He says there are probably a lot of causes conspiring to drive these mass extinctions. But his latest work suggests fluctuations in essential minerals in the ocean could be an important, and so-far completely unexplored, cause.