It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Thursday, April 01, 2021
THIS IS YOUR BRAIN ON SCIENCE
The egg in the X-ray beam
Innovative time-resolved method reveals network formation by and dynamics of proteins
IMAGE: WHEN HEATED, THE PROTEINS IN THE ORIGINALLY TRANSPARENT CHICKEN EGG WHITE FORM A TIGHTLY MESHED, OPAQUE NETWORK. view more
CREDIT: CREDIT: DESY, GESINE BORN
A team of scientists has been using DESY's X-ray source PETRA III to analyse the structural changes that take place in an egg when you cook it. The work reveals how the proteins in the white of a chicken egg unfold and cross-link with each other to form a solid structure when heated. Their innovative method can be of interest to the food industry as well as to the broad field of research surrounding protein analysis. The cooperation of two groups, headed by Frank Schreiber from the University of Tübingen and Christian Gutt from the University of Siegen, with scientists at DESY and European XFEL reports the research in two articles in the journal Physical Review Letters.
Eggs are among the most versatile food ingredients. They can take the form of a gel or a foam, they can be comparatively solid and also serve as the basis for emulsions. At about 80 degrees Celsius, egg white becomes solid and opaque. This is because the proteins in the egg white form a network structure. Studying the exact molecular structure of egg white calls for energetic radiation, such as X-rays, which is able to penetrate the opaque egg white and has a wavelength that is no longer than the structures being examined.
"To understand the structural evolution in detail, you have to study the phenomenon on the micrometre scale," explains Nafisa Begam, the lead author of the first study, who is an Alexander von Humboldt fellow in Schreiber's group. The scientists used so-called X-ray photon correlation spectroscopy (XPCS) with a specific geometry allowing them to determine the structure and the dynamics of the proteins in the egg white.
For their experiments on the P10 beamline at PETRA III the scientists used a chicken egg from a supermarket and filled the egg white into a quartz tube with a diameter of 1.5 millimetres. "Inside, the egg white was heated in a controlled manner while we analysed it with the help of the X-rays," explains DESY co-author Fabian Westermeier. "The X-ray beam was expanded to 0.1 by 0.1 millimetres, to keep the radiation dose below the damage threshold of the protein structures."
The measurements reveal the protein dynamics in the egg white over a period of about a quarter of an hour. During the first three minutes, the protein network grew exponentially, reaching a plateau after about five minutes, at which virtually no more protein links were formed. At this time, the average mesh size of the protein network was about 0.4 micrometres (thousandths of a millimetre).
In the second study, the team used the XPCS technique to investigate the self-organisation of protein solutions into domains with, respectively, high and low protein concentration, as an example of structure formation in cell biology. In the process, they were able to follow the temperature-dependent dynamics over time. "At high protein densities, mobility decreases, which slows down the phase separation. This is important for the special dynamics of the system," reports lead author Anita Girelli from Schreiber's group.
The studies, which were funded by the German Federal Ministry of Education and Research (BMBF), not only reveal new details about the structural changes occurring in egg whites, but also prove the experimental concept, which can be used for other samples too, as demonstrated by the second study. "Successfully applying X-ray photon correlation spectroscopy opens up a new way to study the dynamics of biomolecules, which is essential if we are to understand them properly," Schreiber comments.
DESY is one of the world's leading particle accelerator centres and investigates the structure and function of matter - from the interaction of tiny elementary particles and the behaviour of novel nanomaterials and vital biomolecules to the great mysteries of the universe. The particle accelerators and detectors that DESY develops and builds at its locations in Hamburg and Zeuthen are unique research tools. They generate the most intense X-ray radiation in the world, accelerate particles to record energies and open up new windows onto the universe. DESY is a member of the Helmholtz Association, Germany's largest scientific association, and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90 per cent) and the German federal states of Hamburg and Brandenburg (10 per cent).
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References:
Kinetics of Network Formation and Heterogeneous Dynamics of an Egg White Gel Revealed by Coherent X-Ray Scattering; Nafisa Begam, Anastasia Ragulskaya, Anita Girelli, Hendrik Rahmann, Sivasurender Chandran, Fabian Westermeier, Mario Reiser, Michael Sprung, Fajun Zhang, Christian Gutt, and Frank Schreiber; Physical Review Letters, 2021; DOI: 10.1103/PhysRevLett.126.098001
Microscopic dynamics of liquid-liquid phase separation and domain coarsening in a protein solution revealed by XPCS; Anita Girelli, Hendrik Rahmann, Nafisa Begam, Anastasia Ragulskaya, Mario Reiser, Sivasurender Chandran, Fabian Westermeier, Michael Sprung, Fajun Zhang, Christian Gutt, and Frank Schreiber; Physical Review Letters, 2021 (accepted; in pri
Russian biologists discover a
transmissible cancer lineage in the
Far Eastern mussels
The disease can have an adverse effect on the populations of these molluscs, which are extensively farmed in Russia.
IMAGE: CONFOCAL MICROSCOPY IMAGES OF HAEMOCYTES OF A DN-SUGGESTED MUSSEL (J54) STAINED WITH DAPI (BLUE) AND TRITC-LABELLED PHALLOIDIN (RED). IMAGES (A, B) ARE AT TWO DIFFERENT MAGNIFICATIONS (NOTE THE SCALE BARS).... view more
CREDIT: SPBU
'A transmissible cancer was first discovered in dogs in the middle of the 19th century. It is transmitted sexually from a sick dog to a healthy one, the cancer cells themselves being the infective agent. In the 1990s, a contagious cancer was discovered in the Tasmanian devil. Since the cancer was found in only two species of mammals, scientists used to think that it is quite rare in the nature. However, time has come to reconsider this view. A transmissible cancer appears to be fairly widespread among bivalve molluscs,' says Maria Skazina, a research associate at the Department of Applied Ecology at St Petersburg University and the first author of the publication in Scientific Reports.
Disseminated neoplasia (DN) is a large-scale, fatal cancer disease of bivalve molluscs, which can be compared to leukemia in vertebrates. Diseased mussels have cancer cells, which circulate in the hemolymph, a functional analogue of blood. As neoplasia develops, they infiltrate all tissues and organs, disrupting their work.
The causes of this disease were described for the first time in 2016 in an article published by a group of scientists under the leadership of by Michael Metzger in Nature. The authors showed that disseminated neoplasia was a transmissible cancer lineage. Its cells have their own genotype, different from those of the molluscan hosts. In a way, they are parasites transmitted from sick individuals to healthy ones.
'A study proposing a mechanism of the transfer of cancer cells between individuals was published last year. When the mussel is under stress, the cells of its haemolymph can leave the body, exist for some time in the environment and then invade other mussels. This process has been observed in healthy molluscs. Cancer cells, it would seem, might use this mechanism too,' says Maria Skazina. 'However, this is only a hypothesis. To test it, sophisticated experimental research is necessary'.
Mussels Mytilus are important commercial invertebrates. Two genetic lineages of transmissible cancer are known in them: BTN1 and BTN2 (BTN stands for bivalve transmissible neoplasia). Both of them originated from the Pacific mussel Mytilus trossulus, which is also found in the Far Eastern and Northern seas of Russia.
'So far, BTN1 lineage has been found in a single mussel population at the Pacific coast of North America. BTN2 is much more widespread. Before our research, it had been found in several mussel species in Europe and South America, though not in the parental species Mytilus trossulus,' says Maria Skazina.
In 2019, marine biologists from St Petersburg University, A.V. Zhirmunsky National Research Centre of Marine Biology, and the University of Helsinki joined forces to search for transmissible cancer lineages in the mussels of the Russian seas. To diagnose the disease, they developed an integrated approach, which included cytological and molecular genetic tests, and applied it to the mussels Mytilus trossulus from the Sea of Japan, in which disseminated neoplasia had been previously shown.
In the haemolymph of molluscs from the Gaydamak Bay near the port city of Nakhodka, flow cytometry and immunocytochemistry methods revealed neoplastic cells. They are large, have polyploid nuclei and an abnormal cytoskeleton resembling the spines of a bristling hedgehog. Genotyping of the haemolymph and other tissues by nuclear and mitochondrial characteristics revealed genetic 'chimerism' of the sick mussels, that is, the presence of more than one individual genotype. Multiple alleles (different forms of the same gene that determine the development of a particular trait) were separated by molecular cloning. All diseased mussels were found to have 'additional' genotypes corresponding to BTN2. This means that the scientists from St Petersburg University and their colleagues proved, for the first time, the presence of BTN2 in Mytilus trossulus as well as the presence of transmittable cancer in mussels from the Sea of Japan and the Northwest Pacific.
At the next stage of the research, the scientists used molecular phylogenetic methods to compare the sequences of the mitochondrial BTN genes obtained by them with all the homologous sequences of the mussels themselves stored in the NCBI genetic bank. It turned out that the mitochondria of BTN2 are most similar to those of Mytilus trossulus from the Russian seas. It was probably there that 'patient zero' lived, the mussel that 'gave birth' to this transmissible cancer.
The Baltic Sea mussels were also shown to have BTN2. In 2014, Polish biologists found an unusual mitochondrial genotype in a Baltic mussel, which they interpreted as the genotype of Mytilus trossulus. It is now clear that this was not a mussel genotype, but a BTN2 genotype. It appears that the transmissible cancer that the scientists were looking for in the Far East could be found much closer to St Petersburg. Whether this disease is common among the molluscs of the Baltic Sea remains to be found out.
'This disease is so virulent for invertebrates because they do not have a developed immune system that can reliably distinguish alien cells from their own. Transmissible cancer of molluscs cannot harm humans in any way. However, the disease can be detrimental for the mussel marine culture. We do not yet know how widespread transmissible cancer is among mussels in Russia,' says Maria Skazina.
The scientists now continue to search for transmissible cancer in mussels in different seas of Russia. Preliminary evidence suggests that it is found not only in mussels in the Sea of Japan and the Baltic Sea and that its diversity is not limited to BTN2 lineage. They are also developing a method for rapid diagnosis of the disease in order to monitor it in natural and commercial populations of molluscs.
'Hopefully, our work might be of help for comparative oncology. I think that mussels, as a research model, can tell a lot about the mechanisms of the spread of cancer in different species, including humans,' notes Maria Skazina.
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First interstellar comet may be the most pristine ever found
IMAGE: THIS IMAGE WAS TAKEN WITH THE FORS2 INSTRUMENT ON ESO'S VERY LARGE TELESCOPE IN LATE 2019, WHEN COMET 2I/BORISOV PASSED NEAR THE SUN. SINCE THE COMET WAS TRAVELLING AT BREAKNECK SPEED,... view more
CREDIT: ESO/O. HAINAUT
New observations with the European Southern Observatory's Very Large Telescope (ESO's VLT) indicate that the rogue comet 2I/Borisov, which is only the second and most recently detected interstellar visitor to our Solar System, is one of the most pristine ever observed. Astronomers suspect that the comet most likely never passed close to a star, making it an undisturbed relic of the cloud of gas and dust it formed from.
2I/Borisov was discovered by amateur astronomer Gennady Borisov in August 2019 and was confirmed to have come from beyond the Solar System a few weeks later. "2I/Borisov could represent the first truly pristine comet ever observed," says Stefano Bagnulo of the Armagh Observatory and Planetarium, Northern Ireland, UK, who led the new study published today in Nature Communications. The team believes that the comet had never passed close to any star before it flew by the Sun in 2019.
Bagnulo and his colleagues used the FORS2 instrument on ESO's VLT, located in northern Chile, to study 2I/Borisov in detail using a technique called polarimetry [1]. Since this technique is regularly used to study comets and other small bodies of our Solar System, this allowed the team to compare the interstellar visitor with our local comets.
The team found that 2I/Borisov has polarimetric properties distinct from those of Solar System comets, with the exception of Hale-Bopp. Comet Hale-Bopp received much public interest in the late 1990s as a result of being easily visible to the naked eye, and also because it was one of the most pristine comets astronomers had ever seen. Prior to its most recent passage, Hale-Bopp is thought to have passed by our Sun only once and had therefore barely been affected by solar wind and radiation. This means it was pristine, having a composition very similar to that of the cloud of gas and dust it -- and the rest of the Solar System -- formed from some 4.5 billion years ago.
By analysing the polarisation together with the colour of the comet to gather clues on its composition, the team concluded that 2I/Borisov is in fact even more pristine than Hale-Bopp. This means it carries untarnished signatures of the cloud of gas and dust it formed from.
"The fact that the two comets are remarkably similar suggests that the environment in which 2I/Borisov originated is not so different in composition from the environment in the early Solar System," says Alberto Cellino, a co-author of the study, from the Astrophysical Observatory of Torino, National Institute for Astrophysics (INAF), Italy.
Olivier Hainaut, an astronomer at ESO in Germany who studies comets and other near-Earth objects but was not involved in this new study, agrees. "The main result -- that 2I/Borisov is not like any other comet except Hale-Bopp -- is very strong," he says, adding that "it is very plausible they formed in very similar conditions."
"The arrival of 2I/Borisov from interstellar space represented the first opportunity to study the composition of a comet from another planetary system and check if the material that comes from this comet is somehow different from our native variety," explains Ludmilla Kolokolova, of the University of Maryland in the US, who was involved in the Nature Communications research.
Bagnulo hopes astronomers will have another, even better, opportunity to study a rogue comet in detail before the end of the decade. "ESA is planning to launch Comet Interceptor in 2029, which will have the capability of reaching another visiting interstellar object, if one on a suitable trajectory is discovered," he says, referring to an upcoming mission by the European Space Agency.
An origin story hidden in the dust
Even without a space mission, astronomers can use Earth's many telescopes to gain insight into the different properties of rogue comets like 2I/Borisov. "Imagine how lucky we were that a comet from a system light-years away simply took a trip to our doorstep by chance," says Bin Yang, an astronomer at ESO in Chile, who also took advantage of 2I/Borisov's passage through our Solar System to study this mysterious comet. Her team's results are published in Nature Astronomy.
Yang and her team used data from the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner, as well as from ESO's VLT, to study 2I/Borisov's dust grains to gather clues about the comet's birth and conditions in its home system.
They discovered that 2I/Borisov's coma -- an envelope of dust surrounding the main body of the comet -- contains compact pebbles, grains about one millimetre in size or larger. In addition, they found that the relative amounts of carbon monoxide and water in the comet changed drastically as it neared the Sun. The team, which also includes Olivier Hainaut, says this indicates that the comet is made up of materials that formed in different places in its planetary system.
The observations by Yang and her team suggest that matter in 2I/Borisov's planetary home was mixed from near its star to further out, perhaps because of the existence of giant planets, whose strong gravity stirs material in the system. Astronomers believe that a similar process occurred early in the life of our Solar System.
While 2I/Borisov was the first rogue comet to pass by the Sun, it was not the first interstellar visitor. The first interstellar object to have been observed passing by our Solar System was ?Oumuamua, another object studied with ESO's VLT back in 2017. Originally classified as a comet, ?Oumuamua was later reclassified as an asteroid as it lacked a coma.
Notes
[1] Polarimetry is a technique to measure the polarisation of light. Light becomes polarised, for example, when it goes through certain filters, like the lenses of polarised sunglasses or cometary material. By studying the properties of sunlight polarised by a comet's dust, researchers can gain insights into the physics and chemistry of comets.
More information
This research highlighted in the first part of this release was presented in the paper "Unusual polarimetric properties for interstellar comet 2I/Borisov" to appear in Nature Communications (doi: [10.1038/s41467-021-22000-x] - https://www.nature.com/articles/s41467-021-22000-x ). The second part of the release highlights the study "Compact pebbles and the evolution of volatiles in the interstellar comet 2I/Borisov" to appear in Nature Astronomy (doi: [10.1038/s41550-021-01336-w] - https://www.nature.com/articles/s41550-021-01336-w ).
The team who conducted the first study is composed of S. Bagnulo (Armagh Observatory & Planetarium, UK [Armagh]), A. Cellino (INAF - Osservatorio Astrofisico di Torino, Italy), L. Kolokolova (Department of Astronomy, University of Maryland, US), R. Ne�ič (Armagh; Mullard Space Science Laboratory, University College London, UK; Centre for Planetary Science, University College London/Birkbeck, UK), T. Santana-Ros (Departamento de Fisica, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, Spain; Institut de Ciencies del Cosmos, Universitat de Barcelona, Spain), G. Borisov (Armagh; Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences, Bulgaria), A. A. Christou (Armagh), Ph. Bendjoya (Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France), and M. Devogele (Arecibo Observatory, University of Central Florida, US).
The team who conducted the second study is composed of Bin Yang (European Southern Observatory, Santiago, Chile [ESO Chile]), Aigen Li (Department of Physics and Astronomy, University of Missouri, Columbia, USA), Martin A. Cordiner (Astrochemistry Laboratory, NASA Goddard Space Flight Centre, USA and Department of Physics, Catholic University of America, Washington, DC, USA), Chin-Shin Chang (Joint ALMA Observatory, Santiago, Chile [JAO]), Olivier R. Hainaut (European Southern Observatory, Garching, Germany), Jonathan P. Williams (Institute for Astronomy, University of Hawai'i, Honolulu, USA [IfA Hawai'i]), Karen J. Meech (IfA Hawai'i), Jacqueline V. Keane (IfA Hawai'i), and Eric Villard (JAO and ESO Chile).
ESO is the foremost intergovernmental astronomy organisation in Europe and the world's most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a Strategic Partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world's largest and most sensitive gamma-ray observatory. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become "the world's biggest eye on the sky".
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
IMAGE: HYENAS ARE SLOW-LIVED AND HAVE COMPLEX SOCIAL STRUCTURES view more
CREDIT: DAVE HUDSON
It makes evolutionary sense for long-lived animals to have complex social relationships - such as friends and enemies - researchers say.
Some species and individuals focus their energy on reproduction (live fast, die young), while "slow-living" animals prioritise survival and tend to live longer lives.
In the new paper, University of Exeter scientists argue that natural selection favours complex social structures among slow-living animals - meaning that knowing their friends and enemies is easier for animals with longer lifespans, and helps them live even longer.
Meanwhile, fast-lived species should only bother with such social relationships if it increases their chances of reproduction.
"Slow-living species can afford to invest in social relationships, as they live long enough to enjoy the pay-offs," said Professor Dave Hodgson, Director of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.
"There is strong evidence that strong social bonds are beneficial for survival in slow-living species, including humans.
"We suggest there is a 'positive feedback' - certain social behaviours lead to a longer life, and longer lifespan promotes the development of social bonds."
Professor Hodgson said there is "growing evidence" that differentiated social relationships have a bigger positive effect on survival than on reproduction.
As a result, fast-lived species do not gain the same evolutionary advantages from social relationships as slow-lived species.
Examples of fast-living species could include shrews and crickets, while animals such as mongooses, badgers and hyenas, and indeed humans, have a slower "pace of life".
Pace of life measurements take body size into account. Larger animals tend to live longer, but pace of life can vary significantly in two species of similar size.
Dr Matthew Silk, also of the University of Exeter, said: "If we want to understand more about social relationships and lifespan, we need to think about the relationship between the two.
"More research is needed to explore the social structures of wild animals.
"This could help us understand the links between social bonds, survival and reproduction."
Professor Hodgson said: "Our proposal, that strong and weak social bonds will be more prevalent in slower-living animals, is theoretical.
"We know a lot about animal lifespans, but we know too little about the social structures of many types of animal.
"If we are right, then social bonds could really be key to longer life."
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The paper, published in the journal Trends in Ecology and Evolution, is entitled: "Differentiated social relationships and the pace-of-life-history."
The neural mechanism of a circulatory response to stress
Researchers from the University of Tsukuba discover a novel mechanism by which the brain regulates the cardiovascular system in response to stress
IMAGE: RESEARCHERS FROM THE UNIVERSITY OF TSUKUBA DISCOVERED A NOVEL MECHANISM BY WHICH THE BRAIN REGULATES THE CARDIOVASCULAR SYSTEM IN RESPONSE TO STRESS. BY ELECTRICALLY STIMULATING THE LATERAL HABENULA, THE RESEARCHERS... view more
CREDIT: UNIVERSITY OF TSUKUBA
Tsukuba, Japan - Although the heart beats autonomously, its function can be regulated by the brain in response to, for instance, stressful events. In a new study, researchers from the University of Tsukuba discovered a novel mechanism by which a specific part of the brain, the lateral habenula (LHb), regulates the cardiovascular system.
The cardiovascular system, specifically the heart and blood vessels, have a certain autonomy that allows them to function independently from the brain. In order for the individual to adapt to new, potentially threatening situations, the brain does have some regulatory power over the cardiovascular system. This is achieved by controlling the autonomic nervous system, which consists of the sympathetic and parasympathetic system. While the former has a stimulating effect on the cardiovascular system, including increasing the heart rate and blood pressure, the latter causes the opposite.
"From an evolutionary standpoint, the brain has had in incredibly important function in protecting the individual from predators," says lead author of the study Professor Tadachika Koganezawa. "But even in the absence of predators, our bodies react to stressful situations. In this study, we wanted to determine how the brain regulated the cardiovascular system via the autonomic nervous system."
To achieve their goal, the researchers focused on the LHb. Located deep within the brain, the LHb has been known to control behavioral responses to stressful events, and as such to elicit strong cardiovascular responses. However, the way in which it does so has remained unclear. To address this question, the researchers electrically stimulated the LHb in rats by inserting an electrode through the skull. Stimulation of the LHb resulted in bradycardia (low heart rate) and increased mean arterial pressure (MAP), which is a clinically useful parameter for assessing overall blood pressure.
To determine how the LHb interplays with the autonomic nervous system to regulate the cardiovascular system, the researchers then turned off the parasympathetic system by means of cutting the main parasympathetic nerve, the vagal nerve, or using a drug to antagonize it. While this suppressed the LHb's effect on the heart rate, it did not change the MAP. Antagonizing the sympathetic system did the opposite--it decreased the MAP but did not change the heart rate.
To understand the mechanism by which the LHb elicits these cardiovascular responses, the researchers focused on the neurotransmitter serotonin, which plays an important role in the brain in modulating mood, cognition, and memory, among other functions. While blocking all serotonin receptors significantly reduced the LHb's effect on both the MAP and heart rate, the researchers found that specific subtypes of serotonin receptors were particularly involved in the process.
"These are striking results that show how the lateral habenula controls the cardiovascular system. Our results demonstrate the mechanism of a neural circuit that plays an important role in stress-induced behavioral responses," says author of the study Professor Masayuki Matsumoto.
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The article, "Lateral habenula regulates cardiovascular autonomic responses via the serotonergic system in rats" was published in Frontiers in Neuroscience at https://doi.org/10.3389/fnins.2021.655617.
MONOPOLY CAPITALI$M
Lack of competition and transparency: challenges in the online advertising market
In 2019, 98.5% of Google's revenues, and 83.9% of those of Facebook, came from online advertising services
The first online advertisement was a banner for AT&T that appeared on the HotWired.com website in 1994, when there were just 30 million internet users worldwide. Today, 57% of the world's population has access to the internet and advertising technology has advanced to the point that by 2018 the digital advertising market in Europe alone was worth 55 billion euros. Of this amount, 16.8 billion euros is accounted for by programmatic advertising, which uses artificial intelligence to automate much of the buying and selling of internet advertising.
A new report, published by Open Evidence, a spin-off of the UOC, whose authors include Francisco Lupiáñez, a member of the UOC's Faculty of Information and Communication Sciences and a partner and director of Open Evidence, examines the current situation and the challenges for online advertising. The results reveal an online market that is increasingly dominated by just a few companies (e.g., Google, Facebook) which occupy strategic roles throughout the advertising chain, affecting free competition. Among these challenges, the authors point to "the opacity and lack of transparency" in the market and the need to tackle this issue by combining self-regulation in the sector with domestic and international regulatory measures.
The personalization of advertising
The automation of the advertising market has enabled a better fit between supply and demand, allowing digital media publishers to sell advertising space and advertisers to easily reach large audiences on many websites. The system is based on users' data which is collected by browsers and cookies, i.e. small fragments of code that are stored on devices and record information including demographic details and online behaviour, such as the type of website visited and purchases made. This data is sold to advertisers, who can then use it to personalize advertising messages and show them at the best time and place.
This personalization of advertising activity has gone hand-in-hand with the growth of Google and Facebook, which headed the sector in 2017 with 33% and 16.2% of global revenues, respectively. "Both companies, and, to a lesser extent, Amazon, profit greatly from users' data and from providing a vast inventory of advertisements through their websites and services that can be monetized, generating most of their advertising revenues". The researchers note that "83.9% of Facebook's revenues and 98.5% of Google's revenues in 2019 were generated from advertising services".
Potentially anti-competitive practices
The report also states that this market leadership allows Google and Facebook to benefit from economies of scale and network effects, thanks to the interdependence of their services. It also details how a single company can operate "simultaneously as both buyer and seller". Google, for example, is involved on both the demand side for advertising space, through its DV360 campaign manager, and on the supply side, through its AdX exchange platform. At the same time, it also has a key role in support technologies such as website analytics and as a shopwindow for advertisements via its search engine.
All these advantages, argue the researchers, mean these platforms may potentially engage in "anti-competitive practices" such as favouring their own products, using their market power in new sectors, or acting as a barrier to access, by charging higher rates to advertisers, publishers or providers of complementary services, for example.
Technological complexity, opacity and fraud
The report highlights the opacity of the online advertising market as one of the gravest issues among the consequences of this type of practice. This lack of transparency is due "in part to the complexity of programmatic advertising, but also to the practices of the online platforms". Within these platforms, so-called "walled garden" companies like Amazon and Facebook can use their dominant positions to limit the release of information on the cost, revenues and effectiveness of advertising placement. These activities make it "very difficult to know how the money is spent and where the advertisements appear, leading advertisers and publishers to question the effectiveness of the online advertisement and hindering decision-making".
Fraud is another effect of this opacity in the value chain of advertising technology, including dependence on algorithms and the large number of intermediary businesses. According to 2017 figures published in the report, fraud cost advertisers around 13.6 billion euros globally.
International cooperation between regulatory authorities
The study's conclusions also set out a number of solutions to these issues, including responses at public policy level and at the level of the sector and the companies involved. With regard to the issues of competition and transparency, these include measures such as "the creation of units within the regulatory authorities to deal specifically with digital platforms, with control and executive powers; the establishment of codes of conduct; regulatory reforms on disclosure and interoperability, and, if necessary, anti-trust measures". Given the transnational nature of the platforms, the researchers also recommend "cooperation between regulatory authorities to share learning, improve cross-border regulation and coordinate measures".
The report also examines various self-regulatory initiatives within the industry, such as the development of standards and practices for measuring and ensuring the quality of advertisements, guidelines for improving transparency on tariffs and programmes governing users' privacy and consent. Finally, it emphasizes that no measure is sufficient "in itself", but "a better implementation of existing initiatives and a combination of the proposed measures could be effective in tackling the problems identified in this sector".
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This research by the UOC supports Sustainable Development Goal (SDG) 9, Industry, innovation and infrastructure.
UOC R&I
The UOC's research and innovation (R&I) is helping overcome pressing challenges faced by global societies in the 21st century, by studying interactions between technology and human & social sciences with a specific focus on the network society, e-learning and e-health. Over 500 researchers and 51 research groups work among the University's seven faculties and two research centres: the Internet Interdisciplinary Institute (IN3) and the eHealth Center (eHC).
The United Nations' 2030 Agenda for Sustainable Development and open knowledge serve as strategic pillars for the UOC's teaching, research and innovation. More information:research.uoc.edu. #UOC25years
Early Earth's hot mantle may have led to Archean 'water world'
IMAGE: AN ARTIST'S RENDERING OF EARTH DURING THE ARCHEAN EON, WITH A HAZY ATMOSPHERE, FEW LANDMASSES AND A GLOBAL OCEAN. view more
CREDIT: ALEC BRENNER, HARVARD UNIVERSITY
WASHINGTON--A vast global ocean may have covered early Earth during the early Archean eon, 4 to 3.2 billion years ago, a side effect of having a hotter mantle than today, according to new research.
The new findings challenge earlier assumptions that the size of the Earth's global ocean has remained constant over time and offer clues to how its size may have changed throughout geologic time, according to the study's authors.
Most of Earth's surface water exists in the oceans. But there is a second reservoir of water deep in Earth's interior, in the form of hydrogen and oxygen attached to minerals in the mantle.
A new study in AGU Advances, which publishes high-impact, open-access research and commentary across the Earth and space sciences, estimates how much water the mantle potentially could hold today and how much water it could have stored in the past.
The findings suggest that, since early Earth was hotter than it is today, its mantle may have contained less water because mantle minerals hold onto less water at higher temperatures. Assuming that the mantle currently has more than 0.3-0.8 times the mass of the ocean, a larger surface ocean might have existed during the early Archean. At that time, the mantle was about 1,900-3,000 degrees Kelvin (2,960-4,940 degrees Fahrenheit), compared to 1,600-2,600 degrees Kelvin (2,420-4,220 degrees Fahrenheit) today.
If early Earth had a larger ocean than today, that could have altered the composition of the early atmosphere and reduced how much sunlight was reflected back into space, according to the authors. These factors would have affected the climate and the habitat that supported the first life on Earth.
"It's sometimes easy to forget that the deep interior of a planet is actually important to what's going on with the surface," said Rebecca Fischer, a mineral physicist at Harvard University and co-author of the new study. "If the mantle can only hold so much water, it's got to go somewhere else, so what's going on thousands of kilometers below the surface can have pretty big implications."
Earth's sea level has remained fairly constant during the last 541 million years. Sea levels from earlier in Earth's history are more challenging to estimate, however, because little evidence has survived from the Archean eon. Over geologic time, water can move from the surface ocean to the interior through plate tectonics, but the size of that water flux is not well understood. Because of this lack of information, scientists had assumed the global ocean size remained constant over geologic time.
In the new study, co-author Junjie Dong, a mineral physicist at Harvard University, developed a model to estimate the total amount of water that Earth's mantle could potentially store based on its temperature. He incorporated existing data on how much water different mantle minerals can store and considered which of these 23 minerals would have occurred at different depths and times in Earth's past. He and his co-authors then related those storage estimates to the volume of the surface ocean as Earth cooled.
Jun Korenaga, a geophysicist at Yale University who was not involved in the research, said this is the first time scientists have linked mineral physics data on water storage in the mantle to ocean size. "This connection has never been raised in the past," he said.
Dong and Fischer point out that their estimates of the mantle's water storage capacity carry a lot of uncertainty. For example, scientists don't fully understand how much water can be stored in bridgmanite, the main mineral in the mantle.
The new findings shed light on how the global ocean may have changed over time and can help scientists better understand the water cycles on Earth and other planets, which could be valuable for understanding where life can evolve.
"It is definitely useful to know something quantitative about the evolution of the global water budget," said Suzan van der Lee, a seismologist at Northwestern University who did not participate in the study. "I think this is important for nitty-gritty seismologists like myself, who do imaging of current mantle structure and estimate its water content, but it's also important for people hunting for water-bearing exoplanets and asking about the origins of where our water came from."
Dong and Fischer are now using the same approach to calculate how much water may be held inside Mars.
"Today, Mars looks very cold and dry," Dong said. "But a lot of geochemical and geomorphological evidence suggests that early Mars might have contained some water on the surface - and even a small ocean - so there's a lot of interest in understanding the water cycle on Mars."
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Notes for Journalists
This research study will be freely available for 30 days. Download a PDF copy of the paper here. Neither the paper nor this press release is under embargo.
Paper title:
"Constraining the volume of Earth's early oceans with a temperature?dependent mantle water storage capacity model"
Authors:
Junjie Dong, Harvard University, Cambridge, Massachusetts Rebecca A. Fischer, Harvard University, Cambridge, Massachusetts Lars P. Stixrude, University of California, Los Angeles, California Carolina R. Lithgow?Bertelloni, University of California, Los Angeles, California
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Architecture of Eolian successions under icehouse and greenhouse conditions
New study published in Geological Society of America Bulletin
Boulder, Colo., USA: Anthropogenic climate change is one of the foremost scientific and societal challenges. In part, our response to this global challenge requires an enhanced understanding of how the Earth's surface responds to episodes of climatic heating and cooling. As historical records extend back only a few hundred years, we must look back into the ancient rock record to see how the surface of the Earth has responded to shifts between icehouse (presence of ice at the Earth's poles) and greenhouse (no substantial ice at Earth's poles) climates in the past.
In their study published last week in GSA Bulletin, Grace Cosgrove, Luca Colombera, and Nigel Mountney use a novel relational database (the Database of Aeolian Sedimentary Architecture) to quantify the response of ancient eolian systems (i.e., wind-dominated environments, such as sand dune fields) to global climatic shifts between icehouse and greenhouse climates, as registered in the rock record. They analyzed data on thousands of geological features that preserved a record of eolian processes and landforms, from 34 different eolian systems spanning over two billion years of Earth's history.
Their results demonstrate statistically that preserved sedimentary architectures developed under icehouse and greenhouse conditions are fundamentally different. These differences can be tied to contrasting environmental conditions existing on Earth's surface. During icehouse climates, alternations between glacial and interglacial episodes (caused by changes in the Earth's orbit--the so-called Milankovitch cyclicity) resulted in cycles of glacial-episode accumulation and interglacial deflation.
Greenhouse conditions instead promoted the preservation of eolian elements in the geological record due to elevated water tables and the widespread action of biogenic and chemical stabilizing agents, which protected deposits from wind-driven deflation.
In the context of a rapidly changing climate, the results presented in this work can help predict the potential long-term impact of climate change on Earth surface processes.
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FEATURED ARTICLE
Quantitative analysis of the sedimentary architecture of eolian successions developed under icehouse and greenhouse climatic conditions Grace I.E. Cosgrove; Luca Colombera; Nigel P. Mountney
GSA BULLETIN articles published ahead of print are online at https://bulletin.geoscienceworld.org/content/early/recent. Representatives of the media may obtain complimentary copies of articles by contacting Kea Giles. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to The Geological Society of America Bulletin in articles published. Non-media requests for articles may be directed to GSA Sales and Service, gsaservice@geosociety.org.
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