1,095 research outputs found

    Impact of gravitational radiation higher order modes on single aligned-spin gravitational wave searches for binary black holes

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    Current template-based gravitational wave searches for compact binary coalescences (CBC) use waveform models that neglect the higher order modes content of the gravitational radiation emitted, considering only the quadrupolar (,m)=(2,2)(\ell,|m|)=(2,2) modes. We study the effect of such a neglection for the case of aligned-spin CBC searches for equal-spin (and non-spinning) binary black holes in the context of two versions of Advanced LIGO: the upcoming 2015 version, known as early Advanced LIGO (eaLIGO) and its Zero-Detuned High Energy Power version, that we will refer to as Advanced LIGO (AdvLIGO). In addition, we study the case of a non-spinning search for initial LIGO (iLIGO). We do this via computing the effectualness of the aligned-spin SEOBNRv1 ROM waveform family, which only considers quadrupolar modes, towards hybrid post-Newtonian/Numerical Relativity waveforms which contain higher order modes. We find that for all LIGO versions, losses of more than 10%10\% of events occur for mass ratio q6q\geq6 and M100MM \geq 100M_\odot due to the neglection of higher modes. Moreover, for iLIGO and eaLIGO, losses notably increase up to (39,23)%(39,23)\% respectively for the highest mass (220M)(220M_\odot) and mass ratio (q=8q=8) studied. For the case of early AdvLIGO, losses of 10%10\% occur for M>50MM>50M_\odot and q6q\geq6. Neglection of higher modes leads to observation-averaged systematic parameter biases towards lower spin, total mass and chirp mass. For completeness, we perform a preliminar, non-exhaustive comparison of systematic biases to statistical errors. We find that, for a given SNR, systematic biases dominate over statistical errors at much lower total mass for eaLIGO than for AdvLIGO

    Mapping the Universe Expansion: Enabling percent-level measurements of the Hubble Constant with a single binary neutron-star merger detection

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    The joint observation of the gravitational-wave and electromagnetic signal from the binary neutron-star merger GW170817 allowed for a new independent measurement of the Hubble constant H0H_0, albeit with an uncertainty of about 15\% at 1σ\sigma. Observations of similar sources with a network of future detectors will allow for more precise measurements of H0H_0. These, however, are currently largely limited by the intrinsic degeneracy between the luminosity distance and the inclination of the source in the gravitational-wave signal. We show that the higher-order modes in gravitational waves can be used to break this degeneracy in astrophysical parameter estimation in both the inspiral and post-merger phases of a neutron star merger. We show that for systems at distances similar to GW170817, this method enables percent-level measurements of H0H_0 with a single detection. This would permit the study of time variations and spatial anisotropies of H0H_0 with unprecedented precision. We investigate how different network configurations affect measurements of H0H_0, and discuss the implications in terms of science drivers for the proposed 2.5- and third-generation gravitational-wave detectors. Finally, we show that the precision of H0H_0 measured with these future observatories will be solely limited by redshift measurements of electromagnetic counterparts

    Global Antifungal Profile Optimization of Chlorophenyl Derivatives against Botrytis cinerea and Colletotrichum gloeosporioides

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    Twenty-two aromatic derivatives bearing a chlorine atom and a different chain in the para or meta position were prepared and evaluated for their in vitro antifungal activity against the phytopathogenic fungi Botrytis cinerea and Colletotrichum gloeosporioides. The results showed that maximum inhibition of the growth of these fungi was exhibited for enantiomers S and R of 1-(40-chlorophenyl)- 2-phenylethanol (3 and 4). Furthermore, their antifungal activity showed a clear structure-activity relationship (SAR) trend confirming the importance of the benzyl hydroxyl group in the inhibitory mechanism of the compounds studied. Additionally, a multiobjective optimization study of the global antifungal profile of chlorophenyl derivatives was conducted in order to establish a rational strategy for the filtering of new fungicide candidates from combinatorial libraries. The MOOPDESIRE methodology was used for this purpose providing reliable ranking models that can be used later

    Design Rules for Self-Assembly of 2D Nanocrystal/Metal-Organic Framework Superstructures.

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    We demonstrate the guiding principles behind simple two dimensional self-assembly of MOF nanoparticles (NPs) and oleic acid capped iron oxide (Fe3 O4 ) NCs into a uniform two-dimensional bi-layered superstructure. This self-assembly process can be controlled by the energy of ligand-ligand interactions between surface ligands on Fe3 O4 NCs and Zr6 O4 (OH)4 (fumarate)6 MOF NPs. Scanning transmission electron microscopy (TEM)/energy-dispersive X-ray spectroscopy and TEM tomography confirm the hierarchical co-assembly of Fe3 O4 NCs with MOF NPs as ligand energies are manipulated to promote facile diffusion of the smaller NCs. First-principles calculations and event-driven molecular dynamics simulations indicate that the observed patterns are dictated by combination of ligand-surface and ligand-ligand interactions. This study opens a new avenue for design and self-assembly of MOFs and NCs into high surface area assemblies, mimicking the structure of supported catalyst architectures, and provides a thorough fundamental understanding of the self-assembly process, which could be a guide for designing functional materials with desired structure

    Productividad y trabajo de la mujer en los Estados Unidos

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    Incluye BibliografíaEn este artículo se pretende estimar el efecto que ha tenido sobre la productividad el desplazamiento de mujeres desde el hogar hacia el trabajo asalariado ocurrido en los Estados Unidos en 1960-1980. Se cuestiona en él la validez de una aseveración frecuentemente citada: que la creciente participación de mujeres en la fuerza de trabajo ha reducido la productividad. Se argumenta que el producto nacional bruto tradicional subestima, en relación con una medida más amplia de la producción económica, el crecimiento de la productividad durante períodos de incorporación creciente de mujeres a la fuerza de trabajo. Se demuestra que el desplazamiento de mujeres desde el hogar hacia el trabajo asalariado que ocurrió en esos años representó una reasignación eficiente de horas de trabajo. Las estimaciones cuantitativas de los cambios en la productividad para una economía que incluye tanto el sector doméstico como el de mercado, muestran que el desplazamiento de mujeres fuera del sector doméstico tuvo efectos positivos e importantes en la productividad. Aunque la mayor productividad debido al desplazamiento de mujeres fuera del sector doméstico no contrarrestó completamente la caída de la productividad del sector privado en el período, sí la moderó considerablemente

    Biogeochemistry of carbon in the Amazonian Floodplains over a 2000-km reach: insights from a process-based model.

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    The influence of Amazonian floodplains on the hydrological, sedimentary, and biogeochemical river budget was investigated over a 2000-km reach. A process-based model relying on the closure of chemical fluxes and isotopic signals was implemented. On average for the whole studied reach, the overall fluxes of carbon associated with mineralization and aquatic photosynthesis were estimated to 35.7 and 15.3 Tg C yr21, respectively. Almost 57% of the carbon sequestrated by photosynthesis comes from aerial sources (flooded forest); the remaining 43% resulted from aquatic sources (va´rzea grasses and phytoplankton). The process rates substantially fluctuate over the annual cycle, depending particularly on the extension of flooded area and on the river?floodplain connectivity. As the river level declines, the drastic decrease of turbidity and the lower supply of carbon substrates promote autotrophy to the detriment of heterotrophy, leading to substantial changes of pH and gaseous equilibria in the river water. The main consequences are (i) the side-chain oxidation of dissolved organic matter leading to the concomitant rises of the carbon to nitrogen atomic ratio and nitrate contents and (ii) the sorption of hydrophobic humic acids, which fractionate 13C and thus lead to 13C-depleted particulate organic matter (fine fraction) compared to remaining dissolved organic matter. As the river flow rises, the heterotrophy prevails over autotrophy and this tends to attenuate the chemical signature imprinted by the latter. The significant contribution of aerial autochthonous sources to the budget of carbon indicates that the fluxes of mineralization are sustained by the net primary production of river corridors. The variable extension of submerged areas defines the proportions of CO2 exported by the river and released to the atmosphere. The rate of CO2 outgassing on the studied reach (18.8 Tg C yr21) represents about 50% of the incoming dissolved inorganic carbon flux. The rate of methane emission is estimated as 2.2 Tg C yr21 and that of denitrification is estimated as 0.87 Tg N yr21, representing 1.5 times the flux of dissolved inorganic nitrogen (DIN) exported by the Amazon River at the station of O ´ bidos (0.64 Tg N yr21)

    Histologic features of bone regenerated by means of negative pressure in the context of odontogenic keratocyst

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    Propósito: El objetivo de la presente investigación es describir las características histológicas del hueso regenerado mediante presión negativa (sugosteogénesis) en un grupo de pacientes con diagnóstico de queratoquiste odontogénico (QO) sometidos a descompresión activa y sugosteogénesis por distracción (ADDS) en nuestra institución. Materiales y métodos: Los autores diseñaron un estudio retrospectivo de serie de casos. La población incluyó pacientes con diagnóstico histológico de queratoquiste odontogénico en los que se realizó descompresión activa y sugosteogénesis por distracción seguida de enucleación. Todos los pacientes fueron atendidos y seguidos desde julio de 2019 hasta enero de 2021. La investigación fue aprobada por la Junta de Revisión Institucional, y observó la Declaración de Helsinki sobre protocolo médico. Las variables de este estudio incluyeron la edad, el sexo, la localización anatómica (mandíbula o maxilar) y las características histológicas del hueso regenerado mediante presión negativa. Las características histológicas se definieron como consistentes o inconsistentes con hueso maduro viable. Resultados: Se consideraron las biopsias óseas de 6 pacientes. En total, el 83,33% de los pacientes eran varones y el 16,66% mujeres. El cien por cien de las muestras óseas sometidas a presión negativa mostraban características de hueso maduro viable. Conclusiones: En este estudio, las características histológicas del hueso sometido a presión negativa demostraron las características normales del hueso maduro normal. 2022, El/los autor/es, bajo licencia exclusiva de Springer-Verlag GmbH Alemania, parte de Springer Nature.Purpose: The objective of the present research is to describe the histologic features of the bone regenerated by means of negative pressure (sugosteogenesis) in a group of patients diagnosed with odontogenic keratocyst (OKC) who underwent active decompression and distraction sugosteogenesis (ADDS) at our institution. Materials and methods: The authors designed a retrospective case series study. The population included patients with a histologic diagnosis of odontogenic keratocyst in whom active decompression and distraction sugosteogenesis followed by enucleation was performed. All patients were seen and followed from July 2019 to January 2021. The investigation was approved by the Institutional Review Board, and it observed the Declaration of Helsinki on medical protocol. Variables of this study included age, gender, anatomic location (mandible or maxilla), and histologic characteristics of the bone regenerated by means of negative pressure. Histologic features were defined as being consistent or inconsistent with viable mature bone. Results: Bone biopsies of 6 patients were considered. In total, 83.33% of patients were males and 16.66% females. One hundred percent of the bone samples subjected to negative pressure showed features of viable mature bone. Conclusions: In this study, the histological features of the bone subjected to negative pressure demonstrated the normal characteristics of the mature, normal bone. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature

    Convolutional Neural Networks for the classification of glitches in gravitational-wave data streams

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    We investigate the use of Convolutional Neural Networks (including the modern ConvNeXt network family) to classify transient noise signals (i.e.~glitches) and gravitational waves in data from the Advanced LIGO detectors. First, we use models with a supervised learning approach, both trained from scratch using the Gravity Spy dataset and employing transfer learning by fine-tuning pre-trained models in this dataset. Second, we also explore a self-supervised approach, pre-training models with automatically generated pseudo-labels. Our findings are very close to existing results for the same dataset, reaching values for the F1 score of 97.18% (94.15%) for the best supervised (self-supervised) model. We further test the models using actual gravitational-wave signals from LIGO-Virgo's O3 run. Although trained using data from previous runs (O1 and O2), the models show good performance, in particular when using transfer learning. We find that transfer learning improves the scores without the need for any training on real signals apart from the less than 50 chirp examples from hardware injections present in the Gravity Spy dataset. This motivates the use of transfer learning not only for glitch classification but also for signal classification.Comment: 15 pages, 14 figure
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