570 research outputs found

    Topology by Design in Magnetic nano-Materials: Artificial Spin Ice

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    Artificial Spin Ices are two dimensional arrays of magnetic, interacting nano-structures whose geometry can be chosen at will, and whose elementary degrees of freedom can be characterized directly. They were introduced at first to study frustration in a controllable setting, to mimic the behavior of spin ice rare earth pyrochlores, but at more useful temperature and field ranges and with direct characterization, and to provide practical implementation to celebrated, exactly solvable models of statistical mechanics previously devised to gain an understanding of degenerate ensembles with residual entropy. With the evolution of nano--fabrication and of experimental protocols it is now possible to characterize the material in real-time, real-space, and to realize virtually any geometry, for direct control over the collective dynamics. This has recently opened a path toward the deliberate design of novel, exotic states, not found in natural materials, and often characterized by topological properties. Without any pretense of exhaustiveness, we will provide an introduction to the material, the early works, and then, by reporting on more recent results, we will proceed to describe the new direction, which includes the design of desired topological states and their implications to kinetics.Comment: 29 pages, 13 figures, 116 references, Book Chapte

    Design of a randomized controlled trial for multiple cancer risk behaviors among Spanish-speaking Mexican-origin smokers

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    Background: Smoking, poor diet, and physical inactivity account for as much as 60% of cancer risk. Latinos experience profound disparities in health behaviors, as well as the cancers associated with them. Currently, there is a dearth of controlled trials addressing these health behaviors among Latinos. Further, to the best of our knowledge, no studies address all three behaviors simultaneously, are culturally sensitive, and are guided by formative work with the target population. Latinos represent 14% of the U. S. population and are the fastest growing minority group in the country. Efforts to intervene on these important lifestyle factors among Latinos may accelerate the elimination of cancer-related health disparities

    Hyperdominance in the Amazonian tree flora

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    The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species--less diverse than the North American tree flora--accounts for half of the world's most diverse tree community.This work was supported by Alberta Mennega Stichting; ALCOA Suriname; Banco de la República; Center for Agricultural Research in Suriname; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Plano Nacional de Pós-Graduação); Conselho Nacional de Desenvovimento Científico e Tecnológico of Brazil (CNPq) projects Programa de Pesquisas Ecológicas de Longa Duração (PELD) (558069/2009-6), Programa de Apoio a Núcleos de Excelência da Fundação de Amparo à Pesquisa do Estado do Amazonas (PRONEX-FAPEAM) (1600/2006), Áreas Úmidas, and MAUA; PELD (403792/2012-6), PPBio, CENBAM, Universal (479599/2008-4), and Universal 307807-2009-6; Fundação de Amparo À Pesquisa Do Estado Do Amazonas (APEAM) projects DCR/2006, Hidroveg with FAPESP, and PRONEX with CNPq; FAPESP; Colciencias; Duke University; Ecopetrol; FEPIM 044/2003; the Field Museum; Conservation International/DC (TEAM/INPA Manuas), Gordon and Betty Moore Foundation; Guyana Forestry Commission; Investissement d’Avenir grant of the French Agence Nationale de la Recherche (ANR) (Centre d’Étude de la Biodiversité Amazonienne ANR-10-LABX-0025); Margaret Mee Amazon Trust; Miquel fonds; National Geographic Society (7754-04, 8047-06 to P.M.J.); Netherlands Foundation for the Advancement of Tropical Research WOTRO grants WB85- 335 and W84-581; Primate Conservation Incorporated; Programme Ecosystèmes Tropicaux (French Ministry of Ecology and Sustainable Development; Shell Prospecting and Development Peru; Smithsonian Institution’s Biological Diversity of the Guiana Shield Program; Stichting het van Eeden-fonds; the Body Shop; the Ministry of the Environment of Ecuador; TROBIT; Tropenbos International; NSF (NSF-0743457 and NSF-0101775 to P.M.J.); USAID; Variety Woods Guyana; WWF-Brazil; WWF-Guianas; XIIéme Contrat de Plan Etat Région-Guyane (French Government and European Union); and grants to RAINFOR from the European Union, UK Natural Environment Research Council, the Gordon and Betty Moore Foundation, and U.S. National Geographic Society. O.L.P. is supported by a European Research Council Advanced Grant and a Royal Society Wolfson Research Merit Award

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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    Performance of missing transverse momentum reconstruction with the ATLAS detector using proton–proton collisions at √s = 13 TeV

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    The performance of the missing transverse momentum (EmissT) reconstruction with the ATLAS detector is evaluated using data collected in proton–proton collisions at the LHC at a centre-of-mass energy of 13 TeV in 2015. To reconstruct EmissT, fully calibrated electrons, muons, photons, hadronically decaying τ -leptons, and jets reconstructed from calorimeter energy deposits and charged-particle tracks are used. These are combined with the soft hadronic activity measured by reconstructed charged-particle tracks not associated with the hard objects. Possible double counting of contributions from reconstructed charged-particle tracks from the inner detector, energy deposits in the calorimeter, and reconstructed muons from the muon spectrometer is avoided by applying a signal ambiguity resolution procedure which rejects already used signals when combining the various EmissT contributions. The individual terms as well as the overall reconstructed EmissT are evaluated with various performance metrics for scale (linearity), resolution, and sensitivity to the data-taking conditions. The method developed to determine the systematic uncertainties of the EmissT scale and resolution is discussed. Results are shown based on the full 2015 data sample corresponding to an integrated luminosity of 3.2 fb−1

    Measurement of the t¯tZ and t¯tW cross sections in proton-proton collisions at √s=13 TeV with the ATLAS detector

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    A measurement of the associated production of a top-quark pair (t¯t) with a vector boson (W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented, using 36.1  fb−1 of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. Events are selected in channels with two same- or opposite-sign leptons (electrons or muons), three leptons or four leptons, and each channel is further divided into multiple regions to maximize the sensitivity of the measurement. The t¯tZ and t¯tW production cross sections are simultaneously measured using a combined fit to all regions. The best-fit values of the production cross sections are σt¯tZ=0.95±0.08stat±0.10syst pb and σt¯tW=0.87±0.13stat±0.14syst pb in agreement with the Standard Model predictions. The measurement of the t¯tZ cross section is used to set constraints on effective field theory operators which modify the t¯tZ vertex

    Combined measurement of differential and total cross sections in the H → γγ and the H → ZZ* → 4ℓ decay channels at s=13 TeV with the ATLAS detector

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    A combined measurement of differential and inclusive total cross sections of Higgs boson production is performed using 36.1 fb−1 of 13 TeV proton–proton collision data produced by the LHC and recorded by the ATLAS detector in 2015 and 2016. Cross sections are obtained from measured H→γγ and H→ZZ*(→4ℓ event yields, which are combined taking into account detector efficiencies, resolution, acceptances and branching fractions. The total Higgs boson production cross section is measured to be 57.0−5.9 +6.0 (stat.) −3.3 +4.0 (syst.) pb, in agreement with the Standard Model prediction. Differential cross-section measurements are presented for the Higgs boson transverse momentum distribution, Higgs boson rapidity, number of jets produced together with the Higgs boson, and the transverse momentum of the leading jet. The results from the two decay channels are found to be compatible, and their combination agrees with the Standard Model predictions

    Search for pairs of highly collimated photon-jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    Results of a search for the pair production of photon-jets—collimated groupings of photons—in the ATLAS detector at the Large Hadron Collider are reported. Highly collimated photon-jets can arise from the decay of new, highly boosted particles that can decay to multiple photons collimated enough to be identified in the electromagnetic calorimeter as a single, photonlike energy cluster. Data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 36.7  fb−1, were collected in 2015 and 2016. Candidate photon-jet pair production events are selected from those containing two reconstructed photons using a set of identification criteria much less stringent than that typically used for the selection of photons, with additional criteria applied to provide improved sensitivity to photon-jets. Narrow excesses in the reconstructed diphoton mass spectra are searched for. The observed mass spectra are consistent with the Standard Model background expectation. The results are interpreted in the context of a model containing a new, high-mass scalar particle with narrow width, X, that decays into pairs of photon-jets via new, light particles, a. Upper limits are placed on the cross section times the product of branching ratios σ×B(X→aa)×B(a→γγ)2 for 200  GeV<mX<2  TeV and for ranges of ma from a lower mass of 100 MeV up to between 2 and 10 GeV, depending upon mX. Upper limits are also placed on σ×B(X→aa)×B(a→3π0)2 for the same range of mX and for ranges of ma from a lower mass of 500 MeV up to between 2 and 10 GeV

    SGNP: An Essential Stress Granule/Nucleolar Protein Potentially Involved in 5.8s rRNA Processing/Transport

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    Background: Stress Granules (SG) are sites of accumulation of stalled initiation complexes that are induced following a variety of cellular insults. In a genetic screen for factors involved in protecting human myoblasts from acute oxidative stress, we identified a gene encoding a protein we designate SGNP (Stress Granule and Nucleolar Protein). Methodology/Principal Findings: A gene-trap insertional mutagenesis screen produced one insertion that conferred resistance to sodium arsenite. RT-PCR/39 RACE was used to identify the endogenous gene expressed as a GFP-fusion transcript. SGNP is localized in both the cytoplasm and nucleolus and defines a non-nucleolar compartment containing 5.8S rRNA, a component of the 60S ribosomal subunit. Under oxidative stress, SGNP nucleolar localization decreases and it rapidly co-localizes with stress granules. The decrease in nucleolar SGNP following oxidative stress was accompanied by a large increase in nucleolar 5.8S rRNA. Knockdown of SGNP with shRNA increased global mRNA translation but induced growth arrest and cell death. Conclusions: These results suggest that SGNP is an essential gene that may be involved in ribosomal biogenesis and translational control in response to oxidative stress
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