Science news

• Unlocking the secrets of Ebola

  16-11-2017 23:24
  Scientists have identified a set of biomarkers that indicate which patients infected with the Ebola virus are most at risk of dying from the disease. The results come from one of the most in-depth studies ever of blood samples from patients with Ebola. Researchers found 11 biomarkers that distinguish fatal infections from non-fatal ones and two that, when screened for early upon symptom onset, accurately predict which patients are likely to die.
  
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• Bryozoans: Fossil fills missing evolutionary link

  16-11-2017 23:24
  Scientists recently announced the discovery of a missing evolutionary link -- a fossil of the first known member of the modern bryozoans to grow up into a structure.
  
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• Hot spots of tick-borne diseases in Mongolia

  16-11-2017 22:30
  Given the critical role livestock play in Mongolia, transmission of tick-borne diseases can have very real health and economic implications for livestock and herders. Researchers have explored the interaction between nomadic herders, the livestock they own, and the tick-borne diseases they are exposed to.
  
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• Biological mechanism of a leading cause of childhood blindness revealed in new research

  16-11-2017 22:30
  Scientists have revealed the pathology of cells and structures stricken by optic nerve hypoplasia, a leading cause of childhood blindness in developed nations.
  
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• Current CRISPR gene drives are too strong for outdoor use, studies warn

  16-11-2017 21:00
  
  Self-limiting genetic tools already in development may be able to get around concerns surrounding the use of gene drives.
  
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• Women-run start-ups hampered by bias among male investors, study finds

  16-11-2017 20:21
  Researchers examined data for nearly 18,000 start-ups and found that companies started by women have a harder time finding funding because male investors prefer companies started by men.
  
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• Computer program finds new uses for old drugs

  16-11-2017 20:21
  Researchers have developed a computer program to find new indications for old drugs. The computer program, called DrugPredict, matches existing data about FDA-approved drugs to diseases, and predicts potential drug efficacy. In a recent study, the researchers successfully translated DrugPredict results into the laboratory, and showed common pain medications -- like aspirin -- can kill patient-derived epithelial ovarian cancer cells.
  
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• Passenger pigeon genome shows effects of natural selection in a huge population

  16-11-2017 20:20
  The passenger pigeon is famous for the enormity of its historical population and for its rapid extinction in the face of mass slaughter by humans. Yet it remains a mystery why the species wasn't able to survive in a few small populations. One theory, consistent with the findings of a new study, suggests that passenger pigeons were well adapted to living in huge flocks, but poorly adapted to living in smaller groups.
  
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• On the origins of star stuff: Shedding new light on origin of anti-matter

  16-11-2017 20:20
  Astronomers have used a high-altitude observatory in Mexico to better understand where gamma rays come from. More than 300 massive water tanks sit waiting at the site for cascades of particles initiated by high-energy packets of light called gamma rays -- many of which have more than a million times the energy of a dental X-ray. When these gamma rays smash into the upper atmosphere, they blast apart atoms in the air, producing a shower of particles that moves at nearly the speed of light toward
  
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• How the immune system identifies invading bacteria

  16-11-2017 20:20
  Never-before-seen images of mouse immune system proteins and bacterial bits reveal an inspection strategy that identifies pathogens.
  
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• Excess antielectrons aren’t from nearby dead stars, study says

  16-11-2017 20:19
  
  Pulsars might not be behind excess antimatter, gamma-ray observations suggest.
  
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• Through a Gas, Darkly: Scientists Trace the Origins of Earth's Antimatter

  16-11-2017 20:00 via rss.sciam.com
  Dark matter, rather than pulsars, may be behind an excess of antimatter bombarding our planet
  -- Read more on ScientificAmerican.com
  
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• How the songbird changes its tune

  16-11-2017 19:27
  Researchers have shown how the Bengalese finch, a domesticated songbird, can learn to tweak its song in specific ways depending on context, which could shed light on how the human brain learns to apply different rules depending on the situation, and have implications for understanding human language and movement disorders.
  
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• Bacterium in a beetle makes it a leaf-eater

  16-11-2017 19:27
  A leaf-eating beetle has evolved a symbiotic relationship that allows the insect to break down pectin. The findings on the novel function of the bacterium, which has a surprisingly tiny genome -- much smaller than previous reports on the minimum size required for an organism not subsisting within a host cell.
  
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• Ancient enzyme could boost power of liquid biopsies to detect and profile cancers

  16-11-2017 19:27
  Researchers are developing a new tool for liquid biopsy that can detect RNA biomarkers from cancer cells in a patient's blood much more accurately and completely than other existing methods. This could soon provide doctors with a more complete picture of an individual's disease, improving their chances of finding the best treatment, while also sparing patients the pain, inconvenience and long wait times associated with surgical biopsies.
  
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• Tunable excitons in bilayer graphene

  16-11-2017 19:26
  Excitons, the bound states of an electron and a hole in a solid material, play a key role in the optical properties of insulators and semiconductors. Here, we report the observation of excitons in bilayer graphene (BLG) using photocurrent spectroscopy of high-quality BLG encapsulated in hexagonal boron nitride. We observed two prominent excitonic resonances with narrow line widths that are tunable from the mid-infrared to the terahertz range. These excitons obey optical selection rules distinct
  
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• The structural basis of flagellin detection by NAIP5: A strategy to limit pathogen immune evasion

  16-11-2017 19:26
  Robust innate immune detection of rapidly evolving pathogens is critical for host defense. Nucleotide-binding domain leucine-rich repeat (NLR) proteins function as cytosolic innate immune sensors in plants and animals. However, the structural basis for ligand-induced NLR activation has so far remained unknown. NAIP5 (NLR family, apoptosis inhibitory protein 5) binds the bacterial protein flagellin and assembles with NLRC4 to form a multiprotein complex called an inflammasome. Here we report the
  
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• Structural basis of bacterial transcription activation

  16-11-2017 19:26
  In bacteria, the activation of gene transcription at many promoters is simple and only involves a single activator. The cyclic adenosine 3',5'-monophosphate receptor protein (CAP), a classic activator, is able to activate transcription independently through two different mechanisms. Understanding the class I mechanism requires an intact transcription activation complex (TAC) structure at a high resolution. Here we report a high-resolution cryo–electron microscopy structure of an intact Esc
  
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• State-to-state chemistry for three-body recombination in an ultracold rubidium gas

  16-11-2017 19:26
  Experimental investigation of chemical reactions with full quantum state resolution for all reactants and products has been a long-term challenge. Here we prepare an ultracold few-body quantum state of reactants and demonstrate state-to-state chemistry for the recombination of three spin-polarized ultracold rubidium (Rb) atoms to form a weakly bound Rb2 molecule. The measured product distribution covers about 90% of the final products, and we are able to discriminate between product states with
  
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• Small vulnerable sets determine large network cascades in power grids

  16-11-2017 19:26
  The understanding of cascading failures in complex systems has been hindered by the lack of realistic large-scale modeling and analysis that can account for variable system conditions. Using the North American power grid, we identified, quantified, and analyzed the set of network components that are vulnerable to cascading failures under any out of multiple conditions. We show that the vulnerable set consists of a small but topologically central portion of the network and that large cascades are
  
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• Self-assembling peptide semiconductors

  16-11-2017 19:26
  Semiconductors are central to the modern electronics and optics industries. Conventional semiconductive materials bear inherent limitations, especially in emerging fields such as interfacing with biological systems and bottom-up fabrication. A promising candidate for bioinspired and durable nanoscale semiconductors is the family of self-assembled nanostructures comprising short peptides. The highly ordered and directional intermolecular - interactions and hydrogen-bonding network allow the forma
  
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• Photoionization in the time and frequency domain

  16-11-2017 19:26
  Ultrafast processes in matter, such as the electron emission after light absorption, can now be studied using ultrashort light pulses of attosecond duration (10–18 seconds) in the extreme ultraviolet spectral range. The lack of spectral resolution due to the use of short light pulses has raised issues in the interpretation of the experimental results and the comparison with theoretical calculations. We determine photoionization time delays in neon atoms over a 40–electron volt energy
  
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• Natural selection shaped the rise and fall of passenger pigeon genomic diversity

  16-11-2017 19:26
  The extinct passenger pigeon was once the most abundant bird in North America, and possibly the world. Although theory predicts that large populations will be more genetically diverse, passenger pigeon genetic diversity was surprisingly low. To investigate this disconnect, we analyzed 41 mitochondrial and 4 nuclear genomes from passenger pigeons and 2 genomes from band-tailed pigeons, which are passenger pigeons’ closest living relatives. Passenger pigeons’ large population size appe
  
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• Metabolic recycling of ammonia via glutamate dehydrogenase supports breast cancer biomass

  16-11-2017 19:26
  Ammonia is a ubiquitous by-product of cellular metabolism; however, the biological consequences of ammonia production are not fully understood, especially in cancer. We found that ammonia is not merely a toxic waste product but is recycled into central amino acid metabolism to maximize nitrogen utilization. In our experiments, human breast cancer cells primarily assimilated ammonia through reductive amination catalyzed by glutamate dehydrogenase (GDH); secondary reactions enabled other amino aci
  
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• Loci associated with skin pigmentation identified in African populations

  16-11-2017 19:26
  Despite the wide range of skin pigmentation in humans, little is known about its genetic basis in global populations. Examining ethnically diverse African genomes, we identify variants in or near SLC24A5, MFSD12, DDB1, TMEM138, OCA2, and HERC2 that are significantly associated with skin pigmentation. Genetic evidence indicates that the light pigmentation variant at SLC24A5 was introduced into East Africa by gene flow from non-Africans. At all other loci, variants associated with dark pigmentatio
  
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• Full momentum- and energy-resolved spectral function of a 2D electronic system

  16-11-2017 19:26
  The single-particle spectral function measures the density of electronic states in a material as a function of both momentum and energy, providing central insights into strongly correlated electron phenomena. Here we demonstrate a high-resolution method for measuring the full momentum- and energy-resolved electronic spectral function of a two-dimensional (2D) electronic system embedded in a semiconductor. The technique remains operational in the presence of large externally applied magnetic fiel
  
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• Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth

  16-11-2017 19:26
  The unexpectedly high flux of cosmic-ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the High-Altitude Water Cherenkov Observatory (HAWC), of extended tera–electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources o
  
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• Evolution of flower color pattern through selection on regulatory small RNAs

  16-11-2017 19:26
  Small RNAs (sRNAs) regulate genes in plants and animals. Here, we show that population-wide differences in color patterns in snapdragon flowers are caused by an inverted duplication that generates sRNAs. The complexity and size of the transcripts indicate that the duplication represents an intermediate on the pathway to microRNA evolution. The sRNAs repress a pigment biosynthesis gene, creating a yellow highlight at the site of pollinator entry. The inverted duplication exhibits steep clines in
  
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• Compacted dimensions and singular plasmonic surfaces

  16-11-2017 19:26
  In advanced field theories, there can be more than four dimensions to space, the excess dimensions described as compacted and unobservable on everyday length scales. We report a simple model, unconnected to field theory, for a compacted dimension realized in a metallic metasurface periodically structured in the form of a grating comprising a series of singularities. An extra dimension of the grating is hidden, and the surface plasmon excitations, though localized at the surface, are characterize
  
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• Catalytic molten metals for the direct conversion of methane to hydrogen and separable carbon

  16-11-2017 19:26
  Metals that are active catalysts for methane (Ni, Pt, Pd), when dissolved in inactive low–melting temperature metals (In, Ga, Sn, Pb), produce stable molten metal alloy catalysts for pyrolysis of methane into hydrogen and carbon. All solid catalysts previously used for this reaction have been deactivated by carbon deposition. In the molten alloy system, the insoluble carbon floats to the surface where it can be skimmed off. A 27% Ni–73% Bi alloy achieved 95% methane conversion at 106
  
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• Atomic model for the dimeric FO region of mitochondrial ATP synthase

  16-11-2017 19:26
  Mitochondrial adenosine triphosphate (ATP) synthase produces the majority of ATP in eukaryotic cells, and its dimerization is necessary to create the inner membrane folds, or cristae, characteristic of mitochondria. Proton translocation through the membrane-embedded FO region turns the rotor that drives ATP synthesis in the soluble F1 region. Although crystal structures of the F1 region have illustrated how this rotation leads to ATP synthesis, understanding how proton translocation produces the
  
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• Arbitrary spin-to-orbital angular momentum conversion of light

  16-11-2017 19:26
  Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements—SAM-to–orbital angular momentum (OAM) converters—are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superpositi
  
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• Antibody-dependent enhancement of severe dengue disease in humans

  16-11-2017 19:26
  For dengue viruses 1 to 4 (DENV1-4), a specific range of antibody titer has been shown to enhance viral replication in vitro and severe disease in animal models. Although suspected, such antibody-dependent enhancement of severe disease has not been shown to occur in humans. Using multiple statistical approaches to study a long-term pediatric cohort in Nicaragua, we show that risk of severe dengue disease is highest within a narrow range of preexisting anti-DENV antibody titers. By contrast, we o
  
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• A single mutation in the prM protein of Zika virus contributes to fetal microcephaly

  16-11-2017 19:26
  Zika virus (ZIKV) has evolved into a global health threat because of its unexpected causal link to microcephaly. Phylogenetic analysis reveals that contemporary epidemic strains have accumulated multiple substitutions from their Asian ancestor. Here we show that a single serine-to-asparagine substitution [Ser139->Asn139 (S139N)] in the viral polyprotein substantially increased ZIKV infectivity in both human and mouse neural progenitor cells (NPCs) and led to more severe microcephaly in the mo
  
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• The stacked color sensor: True colors meet minimization

  16-11-2017 17:42
  Red-sensitive, blue-sensitive and green-sensitive color sensors stacked on top of each other instead of being lined up in a mosaic pattern -- this principle could allow image sensors with unprecedented resolution and sensitivity to light to be created. However, up to now, the reality hasn't quite met expectations. Researchers have now developed a sensor prototype that absorbs light almost optimally -- and which is also cheap to produce.
  
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• Could we predict La Niña drought years in advance?

  16-11-2017 17:42
  Scientists' ability to predict the strength and duration of droughts caused by La Niña -- a recurrent cooling pattern in the tropical Pacific Ocean -- has been significantly improved thanks to new research. Their findings, which predict that the current La Niña is likely to stretch into a second year, could help scientists know years in advance how a particular La Niña event is expected to evolve.
  
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• Colliding black holes are reported for a fifth time

  16-11-2017 17:40
  
  LIGO spots another merger, this time with less fanfare.
  
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• Lava or not, exoplanet 55 Cancri e likely to have atmosphere

  16-11-2017 17:37
  Twice as big as Earth, the super-Earth 55 Cancri e was thought to have lava flows on its surface. Now, a new analysis finds this planet likely has an atmosphere whose ingredients could be similar to those of Earth's atmosphere, but thicker.
  
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• New treasures from Tutankhamun's tomb

  16-11-2017 16:51
  Archaeologists have examined embossed gold applications from the sensational find of 1922. The motifs indicate surprising links between the Levant and the Egypt of the pharaohs.
  
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• Neurobiology: Fixated on food?

  16-11-2017 16:51
  Contrast has an impact on the optokinetic reflex, which enables us to clearly perceive the landscape from a moving train. Researchers have now shown that visual features that modulate this ability are encoded in the retina.
  
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• Renaissance of the iron-air battery

  16-11-2017 16:50
  Iron-air batteries promise a considerably higher energy density than present-day lithium-ion batteries. Their main constituent -- iron -- is an abundant and therefore cheap material. Scientists have now successfully observed with nano-scale precision how deposits form at the iron electrode during operation.
  
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• New procedures for DNA stability

  16-11-2017 16:50
  In eukaryotic cells the proximity of the genes to the nuclear pores, which are found in the nuclear membrane, contributes to maintaining the integrity of the genome. This is due to the fact that the anchoring of DNA to the pore during transcription avoids the formation of DNA-RNA hybrids, which are a natural source of DNA breaks and genome instability.
  
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• More than a numbers game: New technique gauges microbial communities by biomass

  16-11-2017 16:50
  New technique provides deeper look at microbial communities by assessing their biomass.
  
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• Discovery of a promising medication for amyotrophic lateral sclerosis (ALS)

  16-11-2017 16:48
  A drug used to treat schizophrenia has the potential to slow the progression of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease for which there is currently no effective cure. After six years of research on several animal models and a few patients, researchers discovered that pimozide stabilizes the disease in the short term. A clinical trial must confirm the efficacy and safety of the drug before it is offered to patients.
  
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• UK and Canada lead global alliance against coal

  16-11-2017 16:29 via bbc.co.uk
  A significant group of nations take a stand against using coal for electricity generation at UN climate talks.
  
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• Colombia zoo gives trafficked elephant root canal surgery

  16-11-2017 16:10 via bbc.co.uk
  The procedure took 30 people three hours to complete. Tantor had been rescued from a ranch in Colombia.
  
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• Cybersecurity: Barely perceptible threat has potential to derail Canada's economy

  16-11-2017 16:04 via cbc.ca
  It's nearly imperceptible, but cybersecurity is nonetheless a haunting prospect for those in the upper echelons of Canadian governments and corporations.
  
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• Uninsured heart attack, stroke patients face ‘catastrophic’ costs

  16-11-2017 15:27
  Heart attack and stroke patients without medical insurance face “devastating” health care costs that can bankrupt them, research shows.
  
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• Species in the north are more vulnerable to climate change

  16-11-2017 15:25
  For the first time, researchers have proposed the hypothesis that animals that live in climate zones at a safe distance from both the poles as well as the tropics have the most to gain from acclimating to changes in climate. The findings contradict previous research in the field.
  
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• Some sugars are good for you, engineers discover

  16-11-2017 15:25
  A new use for sugar has been uncovered, which can aid healing and encourage blood vessel formation, say scientists. This would help tackle the increasing number of non-healing skin wounds associated with age, poor blood supply and diabetes. The breakthrough research could save money for health service providers in the UK and overseas, say the authors.
  
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