Science news

• Montana, Wyoming, Idaho gear up for possible grizzly hunts

  12-05-2016 23:48
  
  HELENA, Mont. (AP) — Hunters soon could be chasing grizzly bears across the ridges of the Rocky Mountains, leaving three states to drum up plans to ensure the iconic species won't be snuffed out soon after recovering from threats to their survival.
  
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• Hunt for Big Bang Gravitational Waves Gets $40 Million Boost

  12-05-2016 23:35 via rss.sciam.com
  
  The nonprofit Simons Foundation will fund a new observatory to search for signs of stretching in the very early universe
  -- Read more on ScientificAmerican.com
  
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• Genes found linking flat-faced dog breeds to brain cancer

  12-05-2016 23:21
  
  And their research also reveals one of the genes might also influence brain cancer in humans.
  
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• [Working Life] My seismic career shift

  12-05-2016 22:31
  Author: Julia MacDougall
  
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• [This Week in Science] Zika virus tested in human brain organoids

  12-05-2016 22:31
  Author: Caroline Ash
  
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• [This Week in Science] The psychological cost of reconciliation

  12-05-2016 22:31
  Author: Gilbert Chin
  
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• [This Week in Science] The global sleep crisis

  12-05-2016 22:31
  Author: Julie A. Phillippi
  
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• [This Week in Science] The effects of rainfall on rainfall

  12-05-2016 22:31
  Author: H. Jesse Smith
  
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• [This Week in Science] Nonlinear optics: A surprise in store?

  12-05-2016 22:31
  Author: Ian S. Osborne
  
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• [This Week in Science] Making RNA in the prebiotic world

  12-05-2016 22:31
  Author: Guy Riddihough
  
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• [This Week in Science] Lightly dispersed palladium

  12-05-2016 22:31
  Author: Phil Szuromi
  
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• [This Week in Science] Let sleeping mice remember

  12-05-2016 22:31
  Author: Peter Stern
  
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• [This Week in Science] Isotopes isolated after impact

  12-05-2016 22:31
  Author: Brent Grocholski
  
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• [This Week in Science] Epistasis and mutational fitness landscape

  12-05-2016 22:31
  Author: Laura M. Zahn
  
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• [This Week in Science] Consequences conferred at a distance

  12-05-2016 22:31
  Author: Sacha Vignieri
  
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• [This Week in Science] Catching a radical in action

  12-05-2016 22:31
  Author: Nicholas S. Wigginton
  
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• [This Week in Science] Carbon links without helpful neighbors

  12-05-2016 22:31
  Author: Jake Yeston
  
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• [This Week in Science] An oncohistone deranges inhibitory chromatin

  12-05-2016 22:31
  Author: Guy Riddihough
  
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• [This Week in Science] An antibody to block viral fusion

  12-05-2016 22:31
  Author: Kristen L. Mueller
  
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• [This Week in Science] A window into Alzheimer's disease

  12-05-2016 22:31
  Author: Orla M. Smith
  
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• [This Week in Science] A twist on optical multiplexing

  12-05-2016 22:31
  Author: Ian S. Osborne
  
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• [This Week in Science] A role for PKCα in Alzheimer's disease

  12-05-2016 22:31
  Author: Leslie K. Ferrarelli
  
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• [This Week in Science] A recipe for intestinal lgA

  12-05-2016 22:31
  Author: Gilbert Chin
  
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• [Research Article] Reconciling after civil conflict increases social capital but decreases individual well-being

  12-05-2016 22:31
  Civil wars divide nations along social, economic, and political cleavages, often pitting one neighbor against another. To restore social cohesion, many countries undertake truth and reconciliation efforts. We examined the consequences of one such effort in Sierra Leone, designed and implemented by a Sierra Leonean nongovernmental organization called Fambul Tok. As a part of this effort, community-level forums are set up in which victims detail war atrocities, and perpetrators confess to war crim
  
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• [Research Article] IgA production requires B cell interaction with subepithelial dendritic cells in Peyer’s patches

  12-05-2016 22:31
  Immunoglobulin A (IgA) induction primarily occurs in intestinal Peyer’s patches (PPs). However, the cellular interactions necessary for IgA class switching are poorly defined. Here we show that in mice, activated B cells use the chemokine receptor CCR6 to access the subepithelial dome (SED) of PPs. There, B cells undergo prolonged interactions with SED dendritic cells (DCs). PP IgA class switching requires innate lymphoid cells, which promote lymphotoxin-β receptor (LTβR)–dependent mainten
  
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• [Report] Zika virus impairs growth in human neurospheres and brain organoids

  12-05-2016 22:31
  Since the emergence of Zika virus (ZIKV), reports of microcephaly have increased considerably in Brazil; however, causality between the viral epidemic and malformations in fetal brains needs further confirmation. We examined the effects of ZIKV infection in human neural stem cells growing as neurospheres and brain organoids. Using immunocytochemistry and electron microscopy, we showed that ZIKV targets human brain cells, reducing their viability and growth as neurospheres and brain organoids. Th
  
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• [Report] The fitness landscape of a tRNA gene

  12-05-2016 22:31
  Fitness landscapes describe the genotype-fitness relationship and represent major determinants of evolutionary trajectories. However, the vast genotype space, coupled with the difficulty of measuring fitness, has hindered the empirical determination of fitness landscapes. Combining precise gene replacement and next-generation sequencing, we quantified Darwinian fitness under a high-temperature challenge for more than 65,000 yeast strains, each carrying a unique variant of the single-copy tRNACCU
  
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• [Report] Radical SAM catalysis via an organometallic intermediate with an Fe–[5′-C]-deoxyadenosyl bond

  12-05-2016 22:31
  Radical S-adenosylmethionine (SAM) enzymes use a [4Fe-4S] cluster to cleave SAM to initiate diverse radical reactions. These reactions are thought to involve the 5′-deoxyadenosyl radical intermediate, which has not yet been detected. We used rapid freeze-quenching to trap a catalytically competent intermediate in the reaction catalyzed by the radical SAM enzyme pyruvate formate-lyase activating enzyme. Characterization of the intermediate by electron paramagnetic resonance and 13C, 57Fe electr
  
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• [Report] Preservation of Earth-forming events in the tungsten isotopic composition of modern flood basalts

  12-05-2016 22:31
  How much of Earth's compositional variation dates to processes that occurred during planet formation remains an unanswered question. High-precision tungsten isotopic data from rocks from two large igneous provinces, the North Atlantic Igneous Province and the Ontong Java Plateau, reveal preservation to the Phanerozoic of tungsten isotopic heterogeneities in the mantle. These heterogeneities, caused by the decay of hafnium-182 in mantle domains with high hafnium/tungsten ratios, were created duri
  
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• [Report] Photochemical route for synthesizing atomically dispersed palladium catalysts

  12-05-2016 22:31
  Atomically dispersed noble metal catalysts often exhibit high catalytic performances, but the metal loading density must be kept low (usually below 0.5%) to avoid the formation of metal nanoparticles through sintering. We report a photochemical strategy to fabricate a stable atomically dispersed palladium–titanium oxide catalyst (Pd1/TiO2) on ethylene glycolate (EG)–stabilized ultrathin TiO2 nanosheets containing Pd up to 1.5%. The Pd1/TiO2 catalyst exhibited high catalytic activity in hydro
  
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• [Report] On-chip noninterference angular momentum multiplexing of broadband light

  12-05-2016 22:31
  Angular momentum division has emerged as a physically orthogonal multiplexing method in high-capacity optical information technologies. However, the typical bulky elements used for information retrieval from the overall diffracted field, based on the interference method, impose a fundamental limit toward realizing on-chip multiplexing. We demonstrate noninterference angular momentum multiplexing by using a mode-sorting nanoring aperture with a chip-scale footprint as small as 4.2 micrometers by
  
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• [Report] Network of epistatic interactions within a yeast snoRNA

  12-05-2016 22:31
  Epistatic interactions play a fundamental role in molecular evolution, but little is known about the spatial distribution of these interactions within genes. To systematically survey a model landscape of intragenic epistasis, we quantified the fitness of ~60,000 Saccharomyces cerevisiae strains expressing randomly mutated variants of the 333-nucleotide-long U3 small nucleolar RNA (snoRNA). The fitness effects of individual mutations were correlated with evolutionary conservation and structural s
  
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• [Report] Large optical nonlinearity of indium tin oxide in its epsilon-near-zero region

  12-05-2016 22:31
  Nonlinear optical phenomena are crucial for a broad range of applications, such as microscopy, all-optical data processing, and quantum information. However, materials usually exhibit a weak optical nonlinearity even under intense coherent illumination. We report that indium tin oxide can acquire an ultrafast and large intensity-dependent refractive index in the region of the spectrum where the real part of its permittivity vanishes. We observe a change in the real part of the refractive index o
  
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• [Report] Histone H3K36 mutations promote sarcomagenesis through altered histone methylation landscape

  12-05-2016 22:31
  Several types of pediatric cancers reportedly contain high-frequency missense mutations in histone H3, yet the underlying oncogenic mechanism remains poorly characterized. Here we report that the H3 lysine 36–to–methionine (H3K36M) mutation impairs the differentiation of mesenchymal progenitor cells and generates undifferentiated sarcoma in vivo. H3K36M mutant nucleosomes inhibit the enzymatic activities of several H3K36 methyltransferases. Depleting H3K36 methyltransferases, or expressing a
  
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• [Report] Fusion peptide of HIV-1 as a site of vulnerability to neutralizing antibody

  12-05-2016 22:31
  The HIV-1 fusion peptide, comprising 15 to 20 hydrophobic residues at the N terminus of the Env-gp41 subunit, is a critical component of the virus-cell entry machinery. Here, we report the identification of a neutralizing antibody, N123-VRC34.01, which targets the fusion peptide and blocks viral entry by inhibiting conformational changes in gp120 and gp41 subunits of Env required for entry. Crystal structures of N123-VRC34.01 liganded to the fusion peptide, and to the full Env trimer, revealed a
  
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• [Report] Empirical evidence of contrasting soil moisture–precipitation feedbacks across the United States

  12-05-2016 22:31
  Soil moisture influences fluxes of heat and moisture originating at the land surface, thus altering atmospheric humidity and temperature profiles. However, empirical and modeling studies disagree on how this affects the propensity for precipitation, mainly owing to the difficulty in establishing causality. We use Granger causality to estimate the relationship between soil moisture and occurrence of subsequent precipitation over the contiguous United States using remotely sensed soil moisture and
  
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• [Report] Causal evidence for the role of REM sleep theta rhythm in contextual memory consolidation

  12-05-2016 22:31
  Rapid eye movement sleep (REMS) has been linked with spatial and emotional memory consolidation. However, establishing direct causality between neural activity during REMS and memory consolidation has proven difficult because of the transient nature of REMS and significant caveats associated with REMS deprivation techniques. In mice, we optogenetically silenced medial septum γ-aminobutyric acid–releasing (MSGABA) neurons, allowing for temporally precise attenuation of the memory-associated th
  
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• [Report] Body shrinkage due to Arctic warming reduces red knot fitness in tropical wintering range

  12-05-2016 22:31
  Reductions in body size are increasingly being identified as a response to climate warming. Here we present evidence for a case of such body shrinkage, potentially due to malnutrition in early life. We show that an avian long-distance migrant (red knot, Calidris canutus canutus), which is experiencing globally unrivaled warming rates at its high-Arctic breeding grounds, produces smaller offspring with shorter bills during summers with early snowmelt. This has consequences half a world away at th
  
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• [Report] A high-yielding, strictly regioselective prebiotic purine nucleoside formation pathway

  12-05-2016 22:31
  The origin of life is believed to have started with prebiotic molecules reacting along unidentified pathways to produce key molecules such as nucleosides. To date, a single prebiotic pathway to purine nucleosides had been proposed. It is considered to be inefficient due to missing regioselectivity and low yields. We report that the condensation of formamidopyrimidines (FaPys) with sugars provides the natural N-9 nucleosides with extreme regioselectivity and in good yields (60%). The FaPys are av
  
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• [Report] A general alkyl-alkyl cross-coupling enabled by redox-active esters and alkylzinc reagents

  12-05-2016 22:31
  Alkyl carboxylic acids are ubiquitous in all facets of chemical science, from natural products to polymers, and represent an ideal starting material with which to forge new connections. This study demonstrates how the same activating principles used for decades to make simple C–N (amide) bonds from carboxylic acids with loss of water can be used to make C–C bonds through coupling with dialkylzinc reagents and loss of carbon dioxide. This disconnection strategy benefits from the use o
  
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• [Policy Forum] Confronting stem cell hype

  12-05-2016 22:31
  The way science is represented to the public can influence understanding and expectations, frame policy debates, and affect the implementation and use of emerging technologies. Inaccurate representations of research may, for example, lead to public confusion about the readiness of a technology for clinical application. As a result, the issue of science “hype”—in which the state of scientific progress, the degree of certainty in models or bench results, or the potential applications of rese
  
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• [Perspective] Toward a prospective molecular evolution

  12-05-2016 22:31
  The field of molecular evolution is concerned with evolutionary changes in genes and genomes and the underlying driving forces behind those changes. Current studies in molecular evolution are almost entirely retrospective, with a focus on the mutations that were fixed during evolution, and the conclusions are often explanatory, offering no predictive insights. Because only a tiny fraction of all mutations that have ever occurred during evolution have been fixed, the “successes” that we see t
  
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• [Perspective] REMembering what you learned

  12-05-2016 22:31
  Which memories are retained, where, and in what form depends on a long afterlife of the acquired information in the brain. Initial steps of consolidation may be completed within a few hours during wakefulness, but other forms of postacquisition processing take longer, extending into sleep (1, 2). The relationship between brain activity during sleep and memory consolidation remains controversial and poorly understood. On page 812 of this issue, Boyce et al. (3) demonstrate that a distinct form of
  
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• [Perspective] Refugee protection and resettlement problems

  12-05-2016 22:31
  In 2015, more than a million refugees and other migrants entered the European Union. They are just a small part of the world's rapidly burgeoning population of displaced people, which climbed by more than 37% between 2009 and 2015 to reach 59.5 million people. Humanitarian aid to these people has been dramatically insufficient, and many displaced people now lack adequate food, medical care, housing, or transportation. As a geographer, I spent 16 months between 2009 and 2013 conducting participan
  
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• [Perspective] Reconciliation in Sierra Leone

  12-05-2016 22:31
  Since the end of World War II, there have been 259 armed conflicts in 159 locations (1). Sierra Leone's civil war began 25 years ago, at a time when roughly 25% of all countries worldwide were experiencing civil war (2). How can individuals and groups recover from such violent conflicts? On page 787 of this issue, Cilliers et al. (3) provide rigorous evidence on the efficacy of one postwar reconciliation strategy that was implemented in 100 communities in Sierra Leone (4).
  Authors: Katherine Cas
  
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• [Perspective] Nanophotonics gets twisted

  12-05-2016 22:31
  Nanophotonics investigates the processing of light at the nanoscale, with the promise of transforming the telecommunication, biomedical, and computation industries. Advances in nanophotonics have traditionally been boosted but also limited by our capabilities of fabricating complex structures at the nanoscale. On page 805 of this issue, Ren et al. (1) try to break free of these limitations with their experimental demonstration of a simple nanostructure that can separate and process complex light
  
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• [Perspective] Living sentinels for climate change effects

  12-05-2016 22:31
  Humans have long used animals as sentinels for threats to their own well-being. Canaries in coal mines are a classic example. On a global scale, studies of birds were key to detecting environmental problems caused by the excessive use of pesticides (1, 2). The recent loss of up to 98% of some vulture populations highlights the widespread dangerous effects of diclofenac use in cattle (3). Bee populations, sentinels for global insect losses, are also declining owing to the combined stress from pes
  
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• [Perspective] Identifying remnants of early Earth

  12-05-2016 22:31
  The chemical composition of Earth's mantle can tell us how our planet formed and how subsequent mantle dynamics have since homogenized the mantle through convective processes. Most terrestrial rocks have a similar tungsten (W) isotope composition (1), but some rocks that have been dated at 2.8 Ga (billion years old) (2), 3.8 Ga (3), and 3.96 Ga (4) have elevated 182W/184W ratios. This is reported as µ182W, in parts per million (ppm) deviation from the bulk silicate Earth. Until now, the outlier
  
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• [Letter] Reminder to deposit DNA sequences

  12-05-2016 22:31
  Authors: Mark Blaxter, Antoine Danchin, Babis Savakis, Kaoru Fukami-Kobayashi, Ken Kurokawa, Sumio Sugano, Richard J. Roberts, Steven L. Salzberg, Chung-I Wu
  
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• [Letter] New allies fight for China's environment

  12-05-2016 22:31
  Authors: S. Lu, J. Zhou, F. Dubee
  
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