928 research outputs found

    Quantum state reconstruction using binary data from on/off photodetection

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    The knowledge of the density matrix of a quantum state plays a fundamental role in several fields ranging from quantum information processing to experiments on foundations of quantum mechanics and quantum optics. Recently, a method has been suggested and implemented in order to obtain the reconstruction of the diagonal elements of the density matrix exploiting the information achievable with realistic on/off detectors, e.g. silicon avalanche photo-diodes, only able to discriminate the presence or the absence of light. The purpose of this paper is to provide an overview of the theoretical and experimental developments of the on/off method, including its extension to the reconstruction of the whole density matrix.Comment: revised version, 11 pages, 6 figures, to appear as a review paper on Adv. Science Let

    Constrained MaxLik reconstruction of multimode photon distributions

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    We address the reconstruction of the full photon distribution of multimode fields generated by seeded parametric down-conversion (PDC). Our scheme is based on on/off avalanche photodetection assisted by maximum-likelihood (MaxLik) estimation and does not involve photon counting. We present a novel constrained MaxLik method that incorporates the request of finite energy to improve the rate of convergence and, in turn, the overall accuracy of the reconstruction

    Análise in silico de genes envolvidos no transporte de nitrato, amônio e uréia em cafeeiro.

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    O nitrogênio (N) é o nutriente mais requerido pelo cafeeiro, sendo adquirido principalmente pelas raízes. As formas de N mais abundantes em solos agrícolas são nitrato (NO3-) e amônio (NH4+), enquanto que a uréia [CO(NH)2 O nitrato (NO] é a principal forma de N utilizada na adubação do cafeeiro. Devido a participação significativa da adubação nitrogenada nos custos de produção do café, é de interesse a identificação de genes envolvidos na absorção radicular e translocação de nitrogênio no cafeeiro, visando uma otimização da eficiência do uso do nitrogênio pela cultura. Neste trabalho foram encontradas etiquetas de sequências expressas (ESTs) no banco de dados do Projeto Genoma Café relacionadas ao transporte das formas mais relevantes na aquisição do N. O número de contigs/singlets para as diferentes famílias de transportadores decresceu na ordem: nitrato (NRT) > amônio (AMT) > uréia (DUR3). A maior expressão e diversidade de transportadores de nitrato refletem a importância desta forma de N na nutrição e fisiologia do cafeeiro, assim como na maioria das outras espécies de plantas

    Deformation Sequence and Paleofluids in Carbonate Buckle Folds Under Transpression (Pag Anticline, External Dinarides, Croatia)

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    Contractional deformation structures at the front of transpressional orogens display complex three-dimensional geometries deviating from the interpretative templates commonly applied in thrust belts. Accordingly, detailed constraints on deformation patterns and associated paleofluid circulation are desirable, especially for fracture geometry and permeability predictive purposes. The Pag anticline, which is located in the Dinaric fold and thrust belt, provides an appropriate field site for studying fold- and fault-related deformation structures in a transpressive setting. We performed a multiscale structural analysis together with petrographic and stable isotope characterization of the deformation-related calcite cements. Structural mapping suggests that the Pag anticline is a detachment fold developed mainly by buckling, since large-scale thrust faults are absent. Fold tightening in a transpressive setting produced a complex deformational structure including two sets of N-S right-lateral and E-W left-lateral late-stage strike-slip fault sets trending oblique to the NW-SE fold axis. The pre-folding deformation pattern includes incipient normal faults likely related to the forebulge stage, veins and stylolites coherent with NE-SW layer parallel shortening contraction in a strike-slip regime, and metric to decametric scale conjugate thrusts coherent with layer parallel shortening in a compressive regime. Buckle folding preceded propagation of a series of accommodation structures during fold tightening. Petrographic and isotopic data indicate meteoric alteration of the Cretaceous platform carbonates in the prefolding stage, likely due to forebulge subaerial exposure. Layer parallel shortening and early syn-folding veins involved formational fluids resulting from mixed marine and meteoric fluids during folding at shallow burial conditions. Eventually, meteoric fluid infiltrated again along strike-slip faults, acting as cross-formational conduits in the postfolding stage

    Quantum and classical characterization of single/few photon detectors

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    This paper's purpose is to review the results recently obtained in the Quantum Optics labs of the National Institute of Metrological Research (INRIM) in the field of single- and few-photon detectors calibration, from both the classical and quantum viewpoint. In the first part of the paper is presented the calibration of a single-photon detector with absolute methods, while in the second part we focus on photon-number-resolving detectors, discussing both the classical and quantum characterization of such devices.Comment: Quantum Matter in pres

    Fire behaviour of non-load bearing double stud cold-formed steel frame walls

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    This work investigates the behaviour of Double stud Light Steel Frame (LSF) walls under ISO834 standard fire through a series of experimental tests. The walls were covered on both sides with one or two fire-resistant gypsum plasterboards (Type F), and the cavity of the steel frame was either empty, partially or fully insulated with ceramic fibre. The fire resistance of the assemblies is improved due to the existence of a wider cavity, the employment of additional gypsum plasterboard layers and the use of ceramic fibre cavity insulation. In partially insulated assemblies, significantly higher fire resistance is achieved when the ceramic fibre is placed towards the fire-exposed gypsum plasterboard. Moreover, the number of studs in contact with the unexposed gypsum plasterboard affects the fire resistance of the specimens. The experimental data acquired is useful to conduct further numerical analyses and experimental studies, as well as to understand the unique thermal behaviour of different configurations of double stud LSF walls at elevated temperatures.info:eu-repo/semantics/publishedVersio

    Programa de computación para el cálculo de formulaciones de pinturas

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    La formulación de pinturas requiere un proceso de cálculo, que si bien es sencillo desde el punto de vista matemático, en la práctica y cuando debe realizarse sobre un gran número de formulaciones, resulta complicado, dado que exige muchas opraciones y consulta de tablas. Esta tarea realizada manualmente se vuelve también insegura y requiere verificaciones, ya que normalmente los errores se van propagando por el cálculo. Con el desarrollo de los pequeños computadores de tercera generación, el cálculo puede realizarse en forma muy rápida y ordenada, lográndose un ahorro de tiempo considerable y una seguridad absoluta en los resultados. A partir del ingreso de datos, este programa admite el uso de tres opciones, que permiten respectivamente: transformar a volumen formulaciones ingresadas en peso; ajustar una formulación a un determinado PVC y contenido de sólidos en volumen, conservando la relación entre los ingredientes de cada grupo y realizar sustituciones de un compuesto por otro en etapas definidas, a la vez que se mantiene un tercer componente como un porcentaje dado del compuesto a reemplazar. Las opciones citadas pueden efectuarse operando sobre matrices comunes a cualquiera de ellas, ya que las operaciones de entrada y salida están ajustadas a un patrón. Esta situación permite, sobre una estructura básica de programa, realizar ampliaciones a otras operaciones que se puedan necesitar. Otra consideración que se efectuó, es que los requerimientos de memoria central se encuentren dentro de las posibilidades de las mini computadoras, por lo que el programa descripto no supera los 16 kbytes de memoria usuario

    Human African trypanosomiasis amongst urban residents in Kinshasa: a case-control study.

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    BACKGROUND: Increasing numbers of human African trypanosomiasis (HAT) cases have been reported in urban residents of Kinshasa, Democratic Republic Congo since 1996. We set up a case-control study to identify risk factors for the disease. METHODS: All residents of the urban part of Kinshasa with parasitologically confirmed HAT and presenting for treatment to the city's specialized HAT clinics between 1 August, 2002 and 28 February, 2003 were included as cases. We defined the urban part as the area with contiguous habitation and a population density >5000 inhabitants per square kilometre. A digital map of the area was drawn based on a satellite image. For each case, two serologically negative controls were selected, matched on age, sex and neighbourhood. Logistic regression models were fitted to control for confounding. RESULTS: The following risk factors were independently associated with HAT: travel, commerce and cultivating fields in Bandundu, and commerce and cultivating fields in the rural part of Kinshasa. No association with activities in the city itself was found. DISCUSSION: In 2002, the emergence of HAT in urban residents of Kinshasa appears mainly linked to disease transmission in Bandundu and rural Kinshasa. We recommend to intensify control of these foci, to target HAT screening in urban residents to people with contact with these foci, to increase awareness of HAT amongst health workers in the urban health structures and to strengthen disease surveillance

    Hepatic ERα accounts for sex differences in the ability to cope with an excess of dietary lipids

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    Objective: Among obesity-associated metabolic diseases, non-alcoholic fatty liver disease (NAFLD) represents an increasing public health issue due to its emerging association with atherogenic dyslipidemia and cardiovascular diseases (CVDs). The lower prevalence of NAFLD in pre-menopausal women compared with men or post-menopausal women led us to hypothesize that the female-inherent ability to counteract this pathology might strongly rely on estrogen signaling. In female mammals, estrogen receptor alpha (ER\u3b1) is highly expressed in the liver, where it acts as a sensor of the nutritional status and adapts the metabolism to the reproductive needs. As in the male liver this receptor is little expressed, we here hypothesize that hepatic ER\u3b1 might account for sex differences in the ability of males and females to cope with an excess of dietary lipids and counteract the accumulation of lipids in the liver. Methods: Through liver metabolomics and transcriptomics we analyzed the relevance of hepatic ER\u3b1 in the metabolic response of males and females to a diet highly enriched in fats (HFD) as a model of diet-induced obesity. Results: The study shows that the hepatic ER\u3b1 strongly contributes to the sex-specific response to an HFD and its action accounts for opposite consequences for hepatic health in males and females. Conclusion: This study identified hepatic ER\u3b1 as a novel target for the design of sex-specific therapies against fatty liver and its cardio-metabolic consequences
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