Science news

• Here's how all our previous Mars missions have ended

  20-10-2016 23:56
  
  We have a long history of failed missions.
  
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• CDC recommends only two HPV shots for younger adolescents

  20-10-2016 23:05
  The U.S. CDC is recommending that 11- to 12-year-olds receive two doses of HPV vaccine at least six months apart rather than the previously recommended three doses to protect against cancers caused by human papillomavirus (HPV) infections.
  
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• Smart mouth: Chinese fish fossil sheds light on jaw evolution

  20-10-2016 23:03
  
  WASHINGTON (Reuters) - A bottom-dwelling, mud-grubbing, armored fish that swam in tropical seas 423 million years ago is fundamentally changing the understanding of the evolution of an indisputably indispensable anatomical feature: the jaw.
  
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• New Cretaceous dinosaur from Queensland

  20-10-2016 22:48
  Researchers have announced the naming of Savannasaurus elliottorum, a new genus and species of dinosaur from western Queensland, Australia. The bones come from the Winton Formation, a geological deposit approximately 95 million years old. Savannasaurus was a medium-sized titanosaur, approximately half the length of a basketball court, with a long neck and a relatively short tail.
  
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• Mystery flares: Edmonton astronomer stumped by his own discovery

  20-10-2016 22:38 via cbc.ca
  
  For Edmonton astronomer Gregory Sivakoff, the sight of never-before-seen explosions in space was the find of a lifetime.
  
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• Earliest evidence in fossil record for right-handedness

  20-10-2016 22:37
  Perhaps the bias against left-handers dates back much further than we thought. By examining striations on teeth of a Homo habilis fossil, researchers have found the earliest evidence for right-handedness in the fossil record dating back 1.8 million years.
  
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• 'Scalper bots' that scoop up concert tickets to be outlawed in Ontario

  20-10-2016 22:16 via cbc.ca
  
  Ontario plans to introduce legislation next spring to outlaw computer "scalper bots" that scoop up huge blocks of tickets to concerts and major sporting events, forcing many customers to the more expensive resale market.
  
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• Could Diet Change Help Treat Blood Cancer or Transplant Patients?

  20-10-2016 21:45 via rss.sciam.com
  
  Scientists make a fundamental discovery about the amino acid valine’s role in blood stem cell development 
  -- Read more on ScientificAmerican.com
  
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• [Working Life] Knocking on opportunity's door

  20-10-2016 21:40
  Author: Diane Shao
  
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• [This Week in Science] Turning off the blue-light response

  20-10-2016 21:40
  Author: Pamela J. Hines
  
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• [This Week in Science] Treating Ebola with a Trojan horse

  20-10-2016 21:40
  Author: Kristen L. Mueller
  
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• [This Week in Science] Sopping up IL-22 drives intestinal disease

  20-10-2016 21:40
  Author: Kristen L. Mueller
  
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• [This Week in Science] Social transfer of pain in mice

  20-10-2016 21:40
  Author: Philip Yeagle
  
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• [This Week in Science] Relating interactions and nematicity

  20-10-2016 21:40
  Author: Jelena Stajic
  
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• [This Week in Science] Persistent infections “interfere” with B cells

  20-10-2016 21:40
  Author: Anand Balasubramani
  
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• [This Week in Science] New players in the repertoire

  20-10-2016 21:40
  Author: Kristen L. Mueller
  
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• [This Week in Science] Metastasis casts a NET

  20-10-2016 21:40
  Author: Yevgeniya Nusinovich
  
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• [This Week in Science] Many tiny force sensors

  20-10-2016 21:40
  Author: Phil Szuromi
  
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• [This Week in Science] Jaws from the jawless

  20-10-2016 21:40
  Author: Sacha Vignieri
  
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• [This Week in Science] How to turn olefins into nucleophiles

  20-10-2016 21:40
  Author: Jake Yeston
  
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• [This Week in Science] Gating a calcium channel

  20-10-2016 21:40
  Author: Valda Vinson
  
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• [This Week in Science] Formaldehyde protects and serves

  20-10-2016 21:40
  Author: Nicholas S. Wigginton
  
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• [This Week in Science] Expect the unexpected

  20-10-2016 21:40
  Author: Sacha Vignieri
  
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• [This Week in Science] Enzymes for making (or breaking) methane

  20-10-2016 21:40
  Author: Nicholas S. Wigginton
  
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• [This Week in Science] Drivers of phytoplankton blooms

  20-10-2016 21:40
  Author: Caroline Ash
  
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• [This Week in Science] Directing the movement of a pathogen

  20-10-2016 21:40
  Author: Wei Wong
  
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• [This Week in Science] Conseting mycobacteria

  20-10-2016 21:40
  Author: Caroline Ash
  
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• [This Week in Science] Belief system dynamics

  20-10-2016 21:40
  Author: Barbara R. Jasny
  
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• [This Week in Science] Almost-off transistors

  20-10-2016 21:40
  Author: Phil Szuromi
  
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• [This Week in Science] Acetylene's scission visualized by selfie

  20-10-2016 21:40
  Author: Jake Yeston
  
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• [This Week in Science] A shocking transformation for silver

  20-10-2016 21:40
  Author: Brent Grocholski
  
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• [Technical Response] Response to Comments on “Reconciliation of the Devils Hole climate record with orbital forcing”

  20-10-2016 21:40
  Winograd and Coplen question the thorium-230 distribution model proposed to explain the age bias observed with increasing depth during Termination II. We have evaluated both criticisms and find that all samples display virtually identical fabrics, argue that the modern setting is not analogous to the conditions during Termination II, and reiterate the robustness of our age models. Our conclusions remain unchanged.
  Authors: Gina E. Moseley, Yuri V. Dublyansky, R. Lawrence Edwards, Kathleen A. Wen
  
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• [Technical Comment] Comment on “Reconciliation of the Devils Hole climate record with orbital forcing”

  20-10-2016 21:40
  Moseley et al. (Reports, 8 January 2016, p. 165) postulate an increase in dissolved thorium isotope 230Th with depth below the water table as the explanation for the differing ages of Termination II. Flow of geothermal water through the Devils Hole caverns precludes this explanation. Deposition of younger secondary calcite into the initial porosity of the calcite comprising their cores is a plausible alternate explanation.
  Author: Isaac J. Winograd
  
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• [Review] Metal-catalyzed reductive coupling of olefin-derived nucleophiles: Reinventing carbonyl addition

  20-10-2016 21:40
  α-Olefins are the most abundant petrochemical feedstock beyond alkanes, yet their use in commodity chemical manufacture is largely focused on polymerization and hydroformylation. The development of byproduct-free catalytic C–C bond–forming reactions that convert olefins to value-added products remains an important objective. Here, we review catalytic intermolecular reductive couplings of unactivated and activated olefin-derived nucleophiles with carbonyl partners. These processes represent
  
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• [Research Article] Structural basis for the gating mechanism of the type 2 ryanodine receptor RyR2

  20-10-2016 21:40
  RyR2 is a high-conductance intracellular calcium (Ca2+) channel that controls the release of Ca2+ from the sarco(endo)plasmic reticulum of a variety of cells. Here, we report the structures of RyR2 from porcine heart in both the open and closed states at near-atomic resolutions determined using single-particle electron cryomicroscopy. Structural comparison reveals a breathing motion of the overall cytoplasmic region resulted from the interdomain movements of amino-terminal domains (NTDs), Helica
  
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• [Report] Ultrafast electron diffraction imaging of bond breaking in di-ionized acetylene

  20-10-2016 21:40
  Visualizing chemical reactions as they occur requires atomic spatial and femtosecond temporal resolution. Here, we report imaging of the molecular structure of acetylene (C2H2) 9 femtoseconds after ionization. Using mid-infrared laser–induced electron diffraction (LIED), we obtained snapshots as a proton departs the [C2H2]2+ ion. By introducing an additional laser field, we also demonstrate control over the ultrafast dissociation process and resolve different bond dynamics for molecules orient
  
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• [Report] The biosynthetic pathway of coenzyme F430 in methanogenic and methanotrophic archaea

  20-10-2016 21:40
  Methyl-coenzyme M reductase (MCR) is the key enzyme of methanogenesis and anaerobic methane oxidation. The activity of MCR is dependent on the unique nickel-containing tetrapyrrole known as coenzyme F430. We used comparative genomics to identify the coenzyme F430 biosynthesis (cfb) genes and characterized the encoded enzymes from Methanosarcina acetivorans C2A. The pathway involves nickelochelation by a nickel-specific chelatase, followed by amidation to form Ni-sirohydrochlorin a,c-diamide. Nex
  
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• [Report] Subthreshold Schottky-barrier thin-film transistors with ultralow power and high intrinsic gain

  20-10-2016 21:40
  The quest for low power becomes highly compelling in newly emerging application areas related to wearable devices in the Internet of Things. Here, we report on a Schottky-barrier indium-gallium-zinc-oxide thin-film transistor operating in the deep subthreshold regime (i.e., near the OFF state) at low supply voltages (<1 volt) and ultralow power (<1 nanowatt). By using a Schottky-barrier at the source and drain contacts, the current-voltage characteristics of the transistor were virtually c
  
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• [Report] Predictable convergence in hemoglobin function has unpredictable molecular underpinnings

  20-10-2016 21:40
  To investigate the predictability of genetic adaptation, we examined the molecular basis of convergence in hemoglobin function in comparisons involving 56 avian taxa that have contrasting altitudinal range limits. Convergent increases in hemoglobin-oxygen affinity were pervasive among high-altitude taxa, but few such changes were attributable to parallel amino acid substitutions at key residues. Thus, predictable changes in biochemical phenotype do not have a predictable molecular basis. Experim
  
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• [Report] Physiological and ecological drivers of early spring blooms of a coastal phytoplankter

  20-10-2016 21:40
  Climate affects the timing and magnitude of phytoplankton blooms that fuel marine food webs and influence global biogeochemical cycles. Changes in bloom timing have been detected in some cases, but the underlying mechanisms remain elusive, contributing to uncertainty in long-term predictions of climate change impacts. Here we describe a 13-year hourly time series from the New England shelf of data on the coastal phytoplankter Synechococcus, during which the timing of its spring bloom varied by 4
  
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• [Report] Photoactivation and inactivation of Arabidopsis cryptochrome 2

  20-10-2016 21:40
  Cryptochromes are blue-light receptors that regulate development and the circadian clock in plants and animals. We found that Arabidopsis cryptochrome 2 (CRY2) undergoes blue light–dependent homodimerization to become physiologically active. We identified BIC1 (blue-light inhibitor of cryptochromes 1) as an inhibitor of plant cryptochromes that binds to CRY2 to suppress the blue light–dependent dimerization, photobody formation, phosphorylation, degradation, and physiological activities of C
  
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• [Report] Observation of a nematic quantum Hall liquid on the surface of bismuth

  20-10-2016 21:40
  Nematic quantum fluids with wave functions that break the underlying crystalline symmetry can form in interacting electronic systems. We examined the quantum Hall states that arise in high magnetic fields from anisotropic hole pockets on the Bi(111) surface. Spectroscopy performed with a scanning tunneling microscope showed that a combination of single-particle effects and many-body Coulomb interactions lift the six-fold Landau level (LL) degeneracy to form three valley-polarized quantum Hall st
  
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• [Report] Network science on belief system dynamics under logic constraints

  20-10-2016 21:40
  Breakthroughs have been made in algorithmic approaches to understanding how individuals in a group influence each other to reach a consensus. However, what happens to the group consensus if it depends on several statements, one of which is proven false? Here, we show how the existence of logical constraints on beliefs affect the collective convergence to a shared belief system and, in contrast, how an idiosyncratic set of arbitrarily linked beliefs held by a few may become held by many.
  Authors:
  
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• [Report] Molecular force spectroscopy with a DNA origami–based nanoscopic force clamp

  20-10-2016 21:40
  Forces in biological systems are typically investigated at the single-molecule level with atomic force microscopy or optical and magnetic tweezers, but these techniques suffer from limited data throughput and their requirement for a physical connection to the macroscopic world. We introduce a self-assembled nanoscopic force clamp built from DNA that operates autonomously and allows massive parallelization. Single-stranded DNA sections of an origami structure acted as entropic springs and exerted
  
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• [Report] Intercellular communication and conjugation are mediated by ESX secretion systems in mycobacteria

  20-10-2016 21:40
  Communal bacterial processes require intercellular communication mediated by secretion systems to coordinate appropriate molecular responses. Intercellular communication has not been described previously in mycobacteria. Here we show that the ESX secretion-system family member ESX-4 is essential for conjugal recipient activity in Mycobacterium smegmatis. Transcription of esx4 genes in the recipient requires coculture with a donor strain and a functional ESX-1 apparatus in the recipient. Converse
  
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• [Report] Formaldehyde stabilization facilitates lignin monomer production during biomass depolymerization

  20-10-2016 21:40
  Practical, high-yield lignin depolymerization methods could greatly increase biorefinery productivity and profitability. However, development of these methods is limited by the presence of interunit carbon-carbon bonds within native lignin, and further by formation of such linkages during lignin extraction. We report that adding formaldehyde during biomass pretreatment produces a soluble lignin fraction that can be converted to guaiacyl and syringyl monomers at near theoretical yields during sub
  
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• [Report] Dynamic creation and evolution of gradient nanostructure in single-crystal metallic microcubes

  20-10-2016 21:40
  We demonstrate the dynamic creation and subsequent static evolution of extreme gradient nanograined structures in initially near–defect-free single-crystal silver microcubes. Extreme nanostructural transformations are imposed by high strain rates, strain gradients, and recrystallization in high-velocity impacts of the microcubes against an impenetrable substrate. We synthesized the silver microcubes in a bottom-up seed-growth process and use an advanced laser-induced projectile impact testing
  
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• [Report] A “Trojan horse” bispecific-antibody strategy for broad protection against ebolaviruses

  20-10-2016 21:40
  There is an urgent need for monoclonal antibody (mAb) therapies that broadly protect against Ebola virus and other filoviruses. The conserved, essential interaction between the filovirus glycoprotein, GP, and its entry receptor Niemann-Pick C1 (NPC1) provides an attractive target for such mAbs but is shielded by multiple mechanisms, including physical sequestration in late endosomes. Here, we describe a bispecific-antibody strategy to target this interaction, in which mAbs specific for NPC1 or t
  
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• [Report] A Silurian maxillate placoderm illuminates jaw evolution

  20-10-2016 21:40
  The discovery of Entelognathus revealed the presence of maxilla, premaxilla, and dentary, supposedly diagnostic osteichthyan bones, in a Silurian placoderm. However, the relationship between these marginal jaw bones and the gnathal plates of conventional placoderms, thought to represent the inner dental arcade, remains uncertain. Here we report a second Silurian maxillate placoderm, which bridges the gnathal and maxillate conditions. We propose that the maxilla, premaxilla, and dentary are homol
  
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• [Report] A pathogenic role for T cell–derived IL-22BP in inflammatory bowel disease

  20-10-2016 21:40
  Intestinal inflammation can impair mucosal healing, thereby establishing a vicious cycle leading to chronic inflammatory bowel disease (IBD). However, the signaling networks driving chronic inflammation remain unclear. Here we report that CD4+ T cells isolated from patients with IBD produce high levels of interleukin-22 binding protein (IL-22BP), the endogenous inhibitor of the tissue-protective cytokine IL-22. Using mouse models, we demonstrate that IBD development requires T cell–derived IL-
  
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