146 research outputs found
Revealing Nanoscale Chemical Heterogeneities in Polycrystalline Mo-BiVO4 Thin Films
Indexación: Scopus.The activity of polycrystalline thin film photoelectrodes is impacted by local variations of the material properties due to the exposure of different crystal facets and the presence of grain/domain boundaries. Here a multi-modal approach is applied to correlate nanoscale heterogeneities in chemical composition and electronic structure with nanoscale morphology in polycrystalline Mo-BiVO4. By using scanning transmission X-ray microscopy, the characteristic structure of polycrystalline film is used to disentangle the different X-ray absorption spectra corresponding to grain centers and grain boundaries. Comparing both spectra reveals phase segregation of V2O5 at grain boundaries of Mo-BiVO4 thin films, which is further supported by X-ray photoelectron spectroscopy and many-body density functional theory calculations. Theoretical calculations also enable to predict the X-ray absorption spectral fingerprint of polarons in Mo-BiVO4. After photo-electrochemical operation, the degraded Mo-BiVO4 films show similar grain center and grain boundary spectra indicating V2O5 dissolution in the course of the reaction. Overall, these findings provide valuable insights into the degradation mechanism and the impact of material heterogeneities on the material performance and stability of polycrystalline photoelectrodes. © 2020 The Authors. Published by Wiley-VCH GmbHhttps://onlinelibrary-wiley-com.recursosbiblioteca.unab.cl/doi/10.1002/smll.20200160
Evolution of the nuclear spin-orbit splitting explored via the <sup>32</sup>Si<i>(d,p)</i><sup>33</sup>Si reaction using SOLARIS
The spin-orbit splitting between neutron 1p orbitals at 33Si has been deduced using the single-neutron-adding (d,p) reaction in inverse kinematics with a beam of 32Si, a long-lived radioisotope. Reaction products were analyzed by the newly implemented SOLARIS spectrometer at the reaccelerated-beam facility at the National Superconducting Cyclotron Laboratory. The measurements show reasonable agreement with shell-model calculations that incorporate modern cross-shell interactions, but they contradict the prediction of proton density depletion based on relativistic mean-field theory. The evolution of the neutron 1p-shell orbitals is systematically studied using the present and existing data in the isotonic chains of = 17, 19, and 21. In each case, a smooth decrease in the separation of the - orbitals is seen as the respective p-orbitals approach zero binding, suggesting that the finite nuclear potential strongly influences the evolution of nuclear structure in this region
The first Hubble diagram and cosmological constraints using superluminous supernovae
This paper has gone through internal review by the DES collaboration.
It has Fermilab preprint number 19-115-AE and DES
publication number 13387. We acknowledge support from EU/FP7-
ERC grant 615929. RCN would like to acknowledge support from
STFC grant ST/N000688/1 and the Faculty of Technology at the
University of Portsmouth. LG was funded by the European Unionâs
Horizon 2020 Framework Programme under the Marie SkĆodowska-
Curie grant agreement no. 839090. This work has been partially
supported by the Spanish grant PGC2018-095317-B-C21 within
the European Funds for Regional Development (FEDER). Funding
for the DES Projects has been provided by the U.S. Department
of Energy, the U.S. National Science Foundation, the Ministry
of Science and Education of Spain, the Science and Technology
Facilities Council of the United Kingdom, the Higher Education
Funding Council for England, the National Center for Supercomputing
Applications at the University of Illinois at Urbana-Champaign,
the Kavli Institute of Cosmological Physics at the University of
Chicago, the Center for Cosmology and Astro-Particle Physics at
the Ohio State University, the Mitchell Institute for Fundamental
Physics and Astronomy at Texas A&M University, Financiadora
de Estudos e Projetos, Fundacž Ëao Carlos Chagas Filho de Amparo
`a Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de
Desenvolvimento CientŽıfico e TecnolŽogico and the MinistŽerio da
CiËencia, Tecnologia e Inovacž Ëao, the Deutsche Forschungsgemeinschaft,
and the Collaborating Institutions in the Dark Energy Survey.
The Collaborating Institutions are Argonne National Laboratory, the
University of California at Santa Cruz, the University of Cambridge,
Centro de Investigaciones EnergÂŽeticas, Medioambientales y Tecnol
ÂŽogicas-Madrid, the University of Chicago, University College
London, the DES-Brazil Consortium, the University of Edinburgh,
the Eidgenšossische Technische Hochschule (ETH) Zšurich, Fermi
NationalAccelerator Laboratory, theUniversity of Illinois atUrbana-
Champaign, the Institut de Ci`encies de lâEspai (IEEC/CSIC), the
Institut de FŽısica dâAltes Energies, Lawrence Berkeley National
Laboratory, the Ludwig-Maximilians Universitšat Mšunchen and the
associated Excellence Cluster Universe, the University of Michigan,
the National Optical Astronomy Observatory, the University of
Nottingham, The Ohio State University, the University of Pennsylvania,
the University of Portsmouth, SLAC National Accelerator
Laboratory, Stanford University, the University of Sussex, Texas
A&M University, and the OzDES Membership Consortium. Based
in part on observations at Cerro Tololo Inter-American Observatory,
National Optical Astronomy Observatory, which is operated by the
Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation.
The DES data management system is supported by the
National Science Foundation under grant numbers AST-1138766
and AST-1536171. The DES participants from Spanish institutions
are partially supported by MINECO under grants AYA2015-
71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV-
2016-0597, and MDM-2015-0509, some of which include ERDF
funds from the European Union. IFAE is partially funded by the
CERCA program of the Generalitat de Catalunya. Research leading
to these results has received funding from the European Research
Council under the European Union Seventh Framework Programme
(FP7/2007-2013) including ERC grant agreements 240672, 291329,
and 306478.We acknowledge support from the Australian Research
Council Centre of Excellence for All-skyAstrophysics (CAASTRO),
through project number CE110001020, and the Brazilian Instituto
Nacional de CiËencia e Tecnologia (INCT) e-Universe (CNPq grant
465376/2014-2).
This paper has been authored by Fermi Research Alliance, LLC
under Contract No.DE-AC02-07CH11359 with theU.S.Department
of Energy, Office of Science, Office of High Energy Physics. The
United States Government retains and the publisher, by accepting
the paper for publication, acknowledges that the United States
Government retains a non-exclusive, paid-up, irrevocable, worldwide
license to publish or reproduce the published form of this paper,
or allow others to do so, for United States Government purposes.We present the first Hubble diagram of superluminous supernovae (SLSNe) out to a redshift of two, together with constraints
on the matter density, M, and the dark energy equation-of-state parameter, w(âĄp/Ï). We build a sample of 20 cosmologically
useful SLSNe I based on light curve and spectroscopy quality cuts. We confirm the robustness of the peakâdecline SLSN I
standardization relation with a larger data set and improved fitting techniques than previous works. We then solve the SLSN
model based on the above standardization via minimization of the Ï2 computed from a covariance matrix that includes statistical
and systematic uncertainties. For a spatially flat cold dark matter ( CDM) cosmological model, we find M = 0.38+0.24
â0.19,
with an rms of 0.27 mag for the residuals of the distance moduli. For a w0waCDM cosmological model, the addition of SLSNe I
to a âbaselineâ measurement consisting of Planck temperature together with Type Ia supernovae, results in a small improvement
in the constraints of w0 and wa of 4 per cent.We present simulations of future surveys with 868 and 492 SLSNe I (depending on
the configuration used) and show that such a sample can deliver cosmological constraints in a flat CDM model with the same
precision (considering only statistical uncertainties) as current surveys that use Type Ia supernovae, while providing a factor of
2â3 improvement in the precision of the constraints on the time variation of dark energy, w0 and wa. This paper represents the
proof of concept for superluminous supernova cosmology, and demonstrates they can provide an independent test of cosmology
in the high-redshift (z > 1) universe.EU/FP7-ERC grant 615929STFC grant ST/N000688/1Faculty of Technology at the
University of PortsmouthEuropean Unionâs
Horizon 2020 Framework Programme under the Marie SkĆodowska-
Curie grant agreement no. 839090Spanish grant PGC2018-095317-B-C21 within
the European Funds for Regional Development (FEDER)U.S. Department
of EnergyU.S. National Science FoundationMinistry
of Science and Education of SpainScience and Technology
Facilities Council of the United KingdomHigher Education
Funding Council for EnglandNational Center for Supercomputing
Applications at the University of Illinois at Urbana-Champaign,Kavli Institute of Cosmological Physics at the University of
ChicagoCenter for Cosmology and Astro-Particle Physics at
the Ohio State UniversityMitchell Institute for Fundamental
Physics and Astronomy at Texas A&M University, Financiadora
de Estudos e Projetos, FundacĂŁo Carlos Chagas Filho de Amparo
`a Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de
Desenvolvimento CientĂfico e TecnolĂłgico and the MinistĂ©rio da
Ciencia, Tecnologia e InovacĂŁoDeutsche ForschungsgemeinschaftCollaborating Institutions in the Dark Energy Survey.National Science Foundation under grant numbers AST-1138766
and AST-1536171.T MINECO under grants AYA2015-
71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV-
2016-0597, and MDM-2015-0509, some of which include ERDF
funds from the European Union.CERCA program of the Generalitat de Catalunya.European Research
Council under the European Union Seventh Framework Programme
(FP7/2007-2013) including ERC grant agreements 240672, 291329,
and 306478.Australian Research
Council Centre of Excellence for All-skyAstrophysics (CAASTRO),
through project number CE110001020Brazilian Instituto
Nacional de CiËencia e Tecnologia (INCT) e-Universe (CNPq grant
465376/2014-2)Fermi Research Alliance, LLC
under Contract No.DE-AC02-07CH11359 with theU.S.Department
of Energy, Office of Science, Office of High Energy Physic
Genotype-Phenotype Correlation in NF1: Evidence for a More Severe Phenotype Associated with Missense Mutations Affecting NF1 Codons 844â848
Neurofibromatosis type 1 (NF1), a common genetic disorder with a birth incidence of 1:2,000â3,000, is characterized by a highly variable clinical presentation. To date, only two clinically relevant intragenic genotype-phenotype correlations have been reported for NF1 missense mutations affecting p.Arg1809 and a single amino acid deletion p.Met922del. Both variants predispose to a distinct mild NF1 phenotype with neither externally visible cutaneous/plexiform neurofibromas nor other tumors. Here, we report 162 individuals (129 unrelated probands and 33 affected relatives) heterozygous for a constitutional missense mutation affecting one of five neighboring NF1 codonsâLeu844, Cys845, Ala846, Leu847, and Gly848âlocated in the cysteine-serine-rich domain (CSRD). Collectively, these recurrent missense mutations affect âŒ0.8% of unrelated NF1 mutation-positive probands in the University of Alabama at Birmingham (UAB) cohort. Major superficial plexiform neurofibromas and symptomatic spinal neurofibromas were more prevalent in these individuals compared with classic NF1-affected cohorts (both p < 0.0001). Nearly half of the individuals had symptomatic or asymptomatic optic pathway gliomas and/or skeletal abnormalities. Additionally, variants in this region seem to confer a high predisposition to develop malignancies compared with the general NF1-affected population (p = 0.0061). Our results demonstrate that these NF1 missense mutations, although located outside the GAP-related domain, may be an important risk factor for a severe presentation. A genotype-phenotype correlation at the NF1 region 844â848 exists and will be valuable in the management and genetic counseling of a significant number of individuals
First cosmology results using SNe Ia from the dark energy survey: analysis, systematic uncertainties, and validation
International audienceWe present the analysis underpinning the measurement of cosmological parameters from 207 spectroscopically classified type Ia supernovae (SNe Ia) from the first three years of the Dark Energy Survey Supernova Program (DES-SN), spanning a redshift range of 0.01
First cosmology results using type Ia supernovae from the Dark Energy Survey: constraints on cosmological parameters
We present the first cosmological parameter constraints using measurements of type Ia supernovae (SNe Ia) from the Dark Energy Survey Supernova Program (DES-SN). The analysis uses a subsample of 207 spectroscopically confirmed SNe Ia from the first three years of DES-SN, combined with a low-redshift sample of 122 SNe from the literature. Our "DES-SN3YR" result from these 329 SNe Ia is based on a series of companion analyses and improvements covering SN Ia discovery, spectroscopic selection, photometry, calibration, distance bias corrections, and evaluation of systematic uncertainties. For a flat LCDM model we find a matter density Omega_m = 0.331 +_ 0.038. For a flat wCDM model, and combining our SN Ia constraints with those from the cosmic microwave background (CMB), we find a dark energy equation of state w = -0.978 +_ 0.059, and Omega_m = 0.321 +_ 0.018. For a flat w0waCDM model, and combining probes from SN Ia, CMB and baryon acoustic oscillations, we find w0 = -0.885 +_ 0.114 and wa = -0.387 +_ 0.430. These results are in agreement with a cosmological constant and with previous constraints using SNe Ia (Pantheon, JLA)
Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7ââfbâ1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale
The first Hubble diagram and cosmological constraints using superluminous supernovae
We present the first Hubble diagram of superluminous supernovae (SLSNe) out to a redshift of two, together with constraints on the matter density, ΩM, and the dark energy equation-of-state parameter, w(âĄp/Ï). We build a sample of 20 cosmologically useful SLSNe I based on light curve and spectroscopy quality cuts. We confirm the robustness of the peakâdecline SLSN I standardization relation with a larger data set and improved fitting techniques than previous works. We then solve the SLSN model based on the above standardization via minimization of the Ï2 computed from a covariance matrix that includes statistical and systematic uncertainties. For a spatially flat Î cold dark matter (ÎCDM) cosmological model, we find ΩM=0.38+0.24â0.19â , with an rms of 0.27 mag for the residuals of the distance moduli. For a w0waCDM cosmological model, the addition of SLSNe I to a âbaselineâ measurement consisting of Planck temperature together with Type Ia supernovae, results in a small improvement in the constraints of w0 and wa of 4 per cent. We present simulations of future surveys with 868 and 492 SLSNe I (depending on the configuration used) and show that such a sample can deliver cosmological constraints in a flat ÎCDM model with the same precision (considering only statistical uncertainties) as current surveys that use Type Ia supernovae, while providing a factor of 2â3 improvement in the precision of the constraints on the time variation of dark energy, w0 and wa. This paper represents the proof of concept for superluminous supernova cosmology, and demonstrates they can provide an independent test of cosmology in the high-redshift (z > 1) universe.</p
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