Oxygen Levels Were Key to Early Animal Evolution, Strongest Evidence Now Shows

Oxygen Levels Were Key to Early Animal Evolution, Strongest Evidence Now Shows

It has long puzzled scientists why, after 3 billion years of nothing more complex than algae, complex animals suddenly started to appear on Earth. Now, a team of researchers has put forward some of the strongest evidence yet to support the hypothesis that high levels of oxygen in the oceans were crucial for the emergence of skeletal animals 550 million years ago.

The new study is the first to distinguish between bodies of water with low and high levels of oxygen. It shows that poorly oxygenated waters did not support the complex life that evolved immediately prior to the Cambrian period, suggesting the presence of oxygen was a key factor in the appearance of these animals.

The research, based on fieldwork carried out in the Nama Group in Namibia, is published in the journal Nature Communications.

Lead author Dr Rosalie Tostevin completed the study analyses as part of her PhD with UCL Earth Sciences, and is now in the Department of Earth Sciences at Oxford University. She said: ‘The question of why it took so long for complex animal life to appear on Earth has puzzled scientists for a long time. One argument has been that evolution simply doesn’t happen very quickly, but another popular hypothesis suggests that a rise in the level of oxygen in the oceans gave simple life-forms the fuel they needed to evolve skeletons, mobility and other typical features of modern animals.

‘Although there is geochemical evidence for a rise in oxygen in the oceans around the time of the appearance of more complex animals, it has been really difficult to prove a causal link. By teasing apart waters with high and low levels of oxygen, and demonstrating that early skeletal animals were restricted to well-oxygenated waters, we have provided strong evidence that the availability of oxygen was a key requirement for the development of these animals. However, these well-oxygenated environments may have been in short supply, limiting habitat space in the ocean for the earliest animals.’

The team, which included other geochemists, palaeoecologists and geologists from UCL and the universities of Edinburgh, Leeds and Cambridge, as well as the Geological Survey of Namibia, analysed the chemical elemental composition of rock samples from the ancient seafloor in the Nama Group – a group of extremely well-preserved rocks in Namibia that are abundant with fossils of early Cloudina, Namacalathus and Namapoikia animals.

The researchers found that levels of elements such as cerium and iron detected in the rocks showed that low-oxygen conditions occurred between well-oxygenated surface waters and fully ‘anoxic’ deep waters. Although abundant in well-oxygenated environments, early skeletal animals did not occupy oxygen-impoverished regions of the shelf, demonstrating that oxygen availability (probably >10 micromolar) was a key requirement for the development of early animal-based ecosystems.

Professor Graham Shields-Zhou (UCL Earth Sciences), one of the co-authors and Dr Tostevin’s PhD supervisor, said: ‘We honed in on the last 10 million years of the Proterozoic Eon as the interval of Earth’s history when today’s major animal groups first grew shells and churned up the sediment, and found that oxygen levels were important to the relationship between environmental conditions and the early development of animals.’


Sitting For Long Periods of Time Is the Cause of 4% of Deaths Worldwide

Sitting For Long Periods of Time Is the Cause of 4% of Deaths Worldwide

Each year people go into September with a number of resolutions. Exercising and not spending so much time on the couch tend to be some of these good intentions. 31% of the worldwide population does not meet the current recommendations for physical activity according to several studies published in 2012 by the journal ‘Lancet’.

In addition, a lack of exercise is associated with major noncommunicable diseases and with deaths of any cause –inactivity is the culprit behind 6% to 9% of total worldwide deaths–.

Today’s lifestyle has an impact on these numbers. In fact, various studies over the last decade have demonstrated how the excessive amount of time we spend sitting down may increase the risk of death, regardless of whether or not we exercise.

A new study, published in the ‘American Journal of Preventive Medicine’ and in which San Jorge University in Zaragoza (Spain) participated, now estimates the proportion of deaths attributable to that ‘chair effect’ in the population of 54 countries, using data from 2002 to 2011.

“It is important to minimise sedentary behaviour in order to prevent premature deaths around the world,” Leandro Rezende, lead author of the study and a researcher at the University of Sao Paulo (Brazil), tells SINC. He also highlights that “cutting down on the amount of time we sit could increase life expectancy by 0.20 years in the countries analysed.”

The results reveal that over 60% of people worldwide spend more than three hours a day sitting down –the average in adults is 4.7 hours/day–, and this is the culprit behind 3.8% of deaths (approximately 433,000 deaths/year).

Among the territories studied, there were more deaths in the regions of the Western Pacific, followed by European countries, the Eastern Mediterranean, America and Southeast Asia.

The highest rates were found in Lebanon (11.6%), the Netherlands (7.6%) and Denmark (6.9%), while the lowest rates were in Mexico (0.6%), Myanmar (1.3%) and Bhutan (1.6%). Spain falls within the average range with 3.7% of deaths due to this ‘chair effect’.

More movement, fewer deaths

The authors calculate that reducing the amount of time we sit by about two hours (i.e., 50%) would mean a 2.3% decrease in mortality (three times less), although it is not possible to confirm whether this is a causal relationship.

Even a more modest reduction in sitting time, by 10% or half an hour per day, could have an immediate impact on all causes of mortality (0.6%) in the countries evaluated.

In the words of the experts, measures aimed at addressing the determining factors behind this sedentary conduct would be necessary. “Some examples of this approach were recently highlighted by the World Health Organization,” adds Rezende.

“For example, a strategic health communication campaign was developed to promote physical activity among women in Tonga (Oceania), while a bicycle-sharing system was developed in Iran in addition to a sustainable transport system in Germany,” he concludes.

Reef Fish See Colors That Humans Cannot

Reef Fish See Colors That Humans Cannot

Researchers at The University of Queensland have established that reef fish see colours that humans cannot.

A team from Professor Justin Marshall’s Sensory Neurobiology Lab at the Queensland Brain Instituteran a series of behavioral experiments with trigger fish, in a bid to decode how they see the world.

Professor Marshall said previous studies had looked into how goldfish saw colour, but this was the first study into how reef fish discriminate colours.

“Coral reefs are the most colourful environments in the world, and it’s now become clear that reef fish see colours we can’t,” Professor Marshall said.

“Some reef fish, such as the anemonefish ‘Nemo’ and other damselfish can see the UV wavelengths we protect ourselves from.

“Triggerfish, on the other hand, see more or less the same colour range we do but their colour discriminations are different.

“Thinking about it, this is no big surprise. Their colour tasks are blue-biased, as they live in a blue ocean.

“Ironically, as the colours of the reef change and disappear because of climate change, we are just beginning to understand how reef inhabitants see and experience their vibrant world,” he said.

Professor Marshall said Dr Connor Champ led a series of detailed behavioural tests, where trigger fish were rewarded for discriminating against progressively similar colours.

It emerged that trigger fish see colours in some colour regions in more detail than humans.

“Many people ask me ‘Why study fish?’ and my first answer is: “Because I love them,” Professor Marshall said.

“But this sort of comparative look at animal systems is vitally important to understand not just the beauty of nature and how to look after it, but to consider the possible applications in the human world.”

Comparative colour vision research at QBI is helping in cancer detection, satellite design and data storage on computers.

The research, published in Royal Society Open Science, was funded by the Australian Research Council.

MRI Scanner Sees Emotions Flickering Across An Idle Mind

MRI Scanner Sees Emotions Flickering Across An Idle Mind

As you relax and let your mind drift aimlessly, you might remember a pleasant vacation, an angry confrontation in traffic or maybe the loss of a loved one.

And now a team of researchers at Duke University say they can see those various emotional states flickering across the human brain.

“It’s getting to be a bit like mind-reading,” said Kevin LaBar, a professor of psychology and neuroscience at Duke. “Earlier studies have shown that functional MRI can identify whether a person is thinking about a face or a house. Our study is the first to show that specific emotions like fear and anger can be decoded from these scans as well.”

A Duke team has mapped the distinct patterns of brain activity that correspond to seven different emotional states. The brain anatomy presented here is an average of data from 32 study subjects. Credit: Philip Kragel, Kevin LaBar, Duke University.

The data produced by a functional MRI hasn’t changed, but the group is applying new multivariate statistics to the scans of brain activity to see different emotions as networks of activity distributed across areas of the conscious and unconscious brain.

These networks were first mapped by the team in a March 2015 paper in the journal Social, Cognitive and Affective Neuroscience. They identified seven different patterns of brain activity reflecting contentment, amusement, surprise, fear, anger, sadness and neutrality.

To build these maps, they had put 32 research subjects into the scanner and exposed them to two music clips and two film clips that had been shown to induce each of the seven emotions. The subjects also completed self-report questionnaires on their mood states for further validation.

Analytical software called a machine learning algorithm was then presented with some of the subjects’ data and tasked with finding a pattern that concurred with each emotional stimulus. Having learned what each of the seven states ought to look like, the algorithm was then presented with the scans of the rest of the study group and asked to identify their emotional states without knowing which emotion prompt they received.

LaBar said the model performed better than chance at this task, despite differences in brain shapes and arousal levels between subjects. “And it proved fairly sensitive,” he said.

The latest study, appearing Sept. 14 in PLoS Biology, followed up by scanning 21 subjects who were not offered stimuli, but were encouraged to let their minds wander. Every thirty seconds, they responded to a questionnaire about their current emotional state.

“We tested whether these seven brain maps of emotions occurred spontaneously while participants were resting in the fMRI scanner without any emotional stimuli being presented,” LaBar said.

Data for the whole brain was collected every 2 seconds and each of these individual scans was compared to the seven patterns. The team examined the scanner data for the ten seconds previous to each self-report of mood, and found that the algorithm accurately predicted the moods the subjects self-reported.

LaBar said another source of validation is the indication that there’s a significant signal of anxiety at the beginning of each subjects’ data as they enter the confined, noisy MRI for the first time. “That’s what you’d expect to see for most people when they first enter the machine.”

In a second group of 499 subjects being scanned for the Duke Neurogenetics Study, the researchers had them rest in the scanner for nearly 9 minutes, and then asked them how depressed and anxious they felt after the scanning session. “We found that the cumulative presence of our ‘sad’ emotion map, summed over time, predicted their depression scores, and the cumulative presence of our ‘fear’ emotion map predicted their anxiety scores,” LaBar said.

This larger group was also tested for personality measures of depression, anxiety, and angry hostility. Again, the maps for depression and anxiety closely mirrored these measures. “We also showed that the cumulative presence of our ‘angry’ emotion map predicted individuals’ angry hostility traits,” LaBar said.

Aside from being an interesting proof of concept, LaBar thinks these new maps of emotional states could be useful in studying people who have poor insight into their emotional status, and might be used in clinical trials to test the effectiveness of treatments to regulate emotions.

LaBar says their conclusions about characteristic networks of brain areas governing emotional states also challenges prevailing theories about how emotions are formed. He adds that a Finnish team led by Lauri Nummenmaa has made similar maps of emotional networks from their brain scanning studies.

In further research, the Duke group will be pursuing a better understanding of the timing of emotional states and the transitions between them, as these may be relevant for understanding affective disorders.

New Record: Quantum Teleportation of a Particle of Light Six Kilometers

New Record: Quantum Teleportation of a Particle of Light Six Kilometers

Through a collaboration between the University of Calgary, The City of Calgary and researchers in the United States, a group of physicists led by Wolfgang Tittel, professor in the Department of Physics and Astronomy at the University of Calgary have successfully demonstrated teleportation of a photon (an elementary particle of light) over a straight-line distance of six kilometres using The City of Calgary’s fibre optic cable infrastructure. The project began with an Urban Alliance seed grant in 2014.

This accomplishment, which set a new record for distance of transferring a quantum state by teleportation, has landed the researchers a spot in the prestigious Nature Photonics scientific journal. The finding was published back-to-back with a similar demonstration by a group of Chinese researchers.

“Such a network will enable secure communication without having to worry about eavesdropping, and allow distant quantum computers to connect,” says Tittel.

Experiment draws on ‘spooky action at a distance’

The experiment is based on the entanglement property of quantum mechanics, also known as “spooky action at a distance” — a property so mysterious that not even Einstein could come to terms with it.

“Being entangled means that the two photons that form an entangled pair have properties that are linked regardless of how far the two are separated,” explains Tittel. “When one of the photons was sent over to City Hall, it remained entangled with the photon that stayed at the University of Calgary.”

Next, the photon whose state was teleported to the university was generated in a third location in Calgary and then also travelled to City Hall where it met the photon that was part of the entangled pair.

“What happened is the instantaneous and disembodied transfer of the photon’s quantum state onto the remaining photon of the entangled pair, which is the one that remained six kilometres away at the university,” says Tittel.

City’s accessible dark fibre makes research possible

The research could not be possible without access to the proper technology. One of the critical pieces of infrastructure that support quantum networking is accessible dark fibre. Dark fibre, so named because of its composition — a single optical cable with no electronics or network equipment on the alignment — doesn’t interfere with quantum technology.

The City of Calgary is building and provisioning dark fibre to enable next-generation municipal services today and for the future.

Wolfgang Tittel, professor in the Department of Physics and Astronomy at the University of Calgary. Photo by Riley Brandt, University of Calgary
Wolfgang Tittel, professor in the Department of Physics and Astronomy at the University of Calgary. Photo by Riley Brandt, University of Calgary.

“By opening The City’s dark fibre infrastructure to the private and public sector, non-profit companies, and academia, we help enable the development of projects like quantum encryption and create opportunities for further research, innovation and economic growth in Calgary,” said Tyler Andruschak, project manager with Innovation and Collaboration at The City of Calgary.

“The university receives secure access to a small portion of our fibre optic infrastructure and The City may benefit in the future by leveraging the secure encryption keys generated out of the lab’s research to protect our critical infrastructure,” said Andruschak. In order to deliver next-generation services to Calgarians, The City has been increasing its fibre optic footprint, connecting all City buildings, facilities and assets.

Timed to within one millionth of one millionth of a second

As if teleporting a photon wasn’t challenging enough, Tittel and his team encountered a number of other roadblocks along the way.

Due to changes in the outdoor temperature, the transmission time of photons from their creation point to City Hall varied over the course of a day — the time it took the researchers to gather sufficient data to support their claim. This change meant that the two photons would not meet at City Hall.

“The challenge was to keep the photons’ arrival time synchronized to within 10 pico-seconds,” says Tittel. “That is one trillionth, or one millionth of one millionth of a second.”

Secondly, parts of their lab had to be moved to two locations in the city, which as Tittel explains was particularly tricky for the measurement station at City Hall which included state-of-the-art superconducting single-photon detectors developed by the National Institute for Standards and Technology, and NASA’s Jet Propulsion Laboratory.

“Since these detectors only work at temperatures less than one degree above absolute zero the equipment also included a compact cryostat,” said Tittel.

Milestone towards a global quantum Internet

This demonstration is arguably one of the most striking manifestations of a puzzling prediction of quantum mechanics, but it also opens the path to building a future quantum internet, the long-term goal of the Tittel group.

New Discovery Shatters Previous Beliefs About Earth’s Origin

New Discovery Shatters Previous Beliefs About Earth’s Origin

A new study led by Western University’s all-star cosmochemist Audrey Bouvier proves that the Earth and other planetary objects formed in the early years of the Solar System share similar chemical origins – a finding at odds with accepted wisdom held by scientists for decades.

The findings were published today by the high-impact journal Nature.

Bouvier, the Canada Research Chair (CRC) in Planetary Materials and an Isotope Cosmochemistry professor in Western’s Department of Earth Sciences, made the game-changing discovery in collaboration with Maud Boyet from the renowned Magmas and Volcanoes Laboratory at Blaise Pascal University in Clermont-Ferrand, France.

With data uncovered through thermal ionization mass spectrometry, Bouvier and Boyet demonstrated that the Earth and other extraterrestrial objects share the same initial levels of Neodymium-142 (142Nd) – one of seven isotopes found in the chemical element neodymium – which is widely distributed in the Earth’s crust and most commonly used for magnets in commercial products like microphones and in-ear headphones.

In 2005, a small variation in 142Nd was detected between chondrites, which are stony meteorites considered essential building blocks of the Earth, and terrestrial rocks. These results were widely interpreted as an early differentiation of the interior of the Earth (including the crust and mantle) and these chondrites within the first 30 million years of its history.

These new results from Bouvier and Boyet show that these differences in 142Nd were in fact already present during the growth of Earth and not introduced later, as was previously believed.

“How the Earth was formed and what type of planetary materials were part of that formation are issues that have puzzled generations of scientists,” says Bouvier, Curator of the Western Meteorite Collection and also a principal investigator at Western’s Centre for Planetary Science and Exploration (CPSX). “And these new isotopic measurements of meteorites provide exciting answers to these questions about our origins and what made the Earth so special.”

By using vastly improved measurement techniques, Bouvier and Boyet deduced that different meteoritical objects found in the Solar System incorporated the elements neodymium (Nd) and samarium (Sm) but with slightly different isotopic compositions. These variations in stable isotopes also show that the Solar System was not uniform during its earliest times and that materials formed from previous generations of stars were incorporated in various proportions into the building blocks of planets.

Massive Holes ‘Punched’ Through A Trail Of Stars Likely Caused By Dark Matter

Massive Holes ‘Punched’ Through A Trail Of Stars Likely Caused By Dark Matter

Researchers have detected two massive holes which have been ‘punched’ through a stream of stars just outside the Milky Way, and found that they were likely caused by clumps of dark matter, the invisible substance which holds galaxies together and makes up a quarter of all matter and energy in the universe.

The scientists, from the University of Cambridge, found the holes by studying the distribution of stars in the Milky Way. While the clumps of dark matter that likely made the holes are gigantic in comparison to our Solar System – with a mass between one million and 100 million times that of the Sun – they are actually the tiniest clumps of dark matter detected to date.

The results, which have been submitted to the Monthly Notices of the Royal Astronomical Society, could help researchers understand the properties of dark matter, by inferring what type of particle this mysterious substance could be made of. According to their calculations and simulations, dark matter is likely made up of particles more massive and more sluggish than previously thought, although such a particle has yet to be discovered.

“While we do not yet understand what dark matter is formed of, we know that it is everywhere,” said Dr Denis Erkal from Cambridge’s Institute of Astronomy, the paper’s lead author. “It permeates the universe and acts as scaffolding around which astrophysical objects made of ordinary matter – such as galaxies – are assembled.”

Current theory on how the universe was formed predicts that many of these dark matter building blocks have been left unused, and there are possibly tens of thousands of small clumps of dark matter swarming in and around the Milky Way. These small clumps, known as dark matter sub-haloes, are completely dark, and don’t contain any stars, gas or dust.

Dark matter cannot be directly measured, and so its existence is usually inferred by the gravitational pull it exerts on other objects, such as by observing the movement of stars in a galaxy. But since sub-haloes don’t contain any ordinary matter, researchers need to develop alternative techniques in order to observe them.

The technique the Cambridge researchers developed was to essentially look for giant holes punched through a stream of stars. These streams are the remnants of small satellites, either dwarf galaxies or globular clusters, which were once in orbit around our own galaxy, but the strong tidal forces of the Milky Way have torn them apart. The remnants of these former satellites are often stretched out into long and narrow tails of stars, known as stellar streams.

“Stellar streams are actually simple and fragile structures,” said co-author Dr Sergey Koposov. “The stars in a stellar stream closely follow one another since their orbits all started from the same place. But they don’t actually feel each other’s presence, and so the apparent coherence of the stream can be fractured if a massive body passes nearby. If a dark matter sub-halo passes through a stellar stream, the result will be a gap in the stream which is proportional to the mass of the body that created it.”

The researchers used data from the stellar streams in the Palomar 5 globular cluster to look for evidence of a sub-halo fly-by. Using a new modelling technique, they were able to observe the stream with greater precision than ever before. What they found was a pair of wrinkled tidal tails, with two gaps of different widths.

By running thousands of computer simulations, the researchers determined that the gaps were consistent with a fly-by of a dark matter sub-halo. If confirmed, these would be the smallest dark matter clumps detected to date.

“If dark matter can exist in clumps smaller than the smallest dwarf galaxy, then it also tells us something about the nature of the particles which dark matter is made of – namely that it must be made of very massive particles,” said co-author Dr Vasily Belokurov. “This would be a breakthrough in our understanding of dark matter.”

The reason that researchers can make this connection is that the mass of the smallest clump of dark matter is closely linked to the mass of the yet unknown particle that dark matter is composed of. More precisely, the smaller the clumps of dark matter, the higher the mass of the particle.

Since we do not yet know what dark matter is made of, the simplest way to characterise the particles is to assign them a particular energy or mass. If the particles are very light, then they can move and disperse into very large clumps. But if the particles are very massive, then they can’t move very fast, causing them to condense – in the first instance – into very small clumps.

“Mass is related to how fast these particles can move, and how fast they can move tells you about their size,” said Belokurov. “So that’s why it’s so interesting to detect very small clumps of dark matter, because it tells you that the dark matter particle itself must be very massive.”

“If our technique works as predicted, in the near future we will be able to use it to discover even smaller clumps of dark matter,” said Erkal. “It’s like putting dark matter goggles on and seeing thousands of dark clumps each more massive than a million suns whizzing around.”