594 research outputs found

    Design and advancement status of the Beam Expander Testing X-ray facility (BEaTriX)

    Full text link
    The BEaTriX (Beam Expander Testing X-ray facility) project is an X-ray apparatus under construction at INAF/OAB to generate a broad (200 x 60 mm2), uniform and low-divergent X-ray beam within a small lab (6 x 15 m2). BEaTriX will consist of an X-ray source in the focus a grazing incidence paraboloidal mirror to obtain a parallel beam, followed by a crystal monochromation system and by an asymmetrically-cut diffracting crystal to perform the beam expansion to the desired size. Once completed, BEaTriX will be used to directly perform the quality control of focusing modules of large X-ray optics such as those for the ATHENA X-ray observatory, based on either Silicon Pore Optics (baseline) or Slumped Glass Optics (alternative), and will thereby enable a direct quality control of angular resolution and effective area on a number of mirror modules in a short time, in full X-ray illumination and without being affected by the finite distance of the X-ray source. However, since the individual mirror modules for ATHENA will have an optical quality of 3-4 arcsec HEW or better, BEaTriX is required to produce a broad beam with divergence below 1-2 arcsec, and sufficient flux to quickly characterize the PSF of the module without being significantly affected by statistical uncertainties. Therefore, the optical components of BEaTriX have to be selected and/or manufactured with excellent optical properties in order to guarantee the final performance of the system. In this paper we report the final design of the facility and a detailed performance simulation.Comment: Accepted paper, pre-print version. The finally published manuscript can be downloaded from http://dx.doi.org/10.1117/12.223895

    A Bootstrapped Modularised method of Global Sensitivity Analysis applied to Probabilistic Seismic Hazard Assessment

    Get PDF
    Probabilistic Seismic Hazard Assessment (PSHA) evaluates the probability of exceedance of a given earthquake intensity threshold like the Peak Ground Acceleration, at a target site for a given exposure time. The stochasticity of the occurrence of seismic events is modelled by stochastic processes and the propagation of the earthquake wave in the soil is typically evaluated by empirical relationships called Ground Motion Prediction Equations. The large uncertainty affecting PSHA is quantified by defining alternative model settings and/or model parametri-zations. In this work, we propose a novel Bootstrapped Modularised Global Sensitivity Analysis (BMGSA) method for identifying the model parameters most important for the uncertainty in PSHA, that consists in generating alternative artificial datasets by bootstrapping an available input-output dataset and aggregating the individual rankings obtained with the modularized method from each of those.The proposed method is tested on a realistic PSHA case study in Italy. The results are compared with a standard variance-based Global Sensitivity Analysis (GSA) method of literature. The novelty and strength of the proposed BMGSA method are both in the fact that its application only requires input-output data and not the use of a PSHA code for repeated calculations

    MEMÓRIAS do Período Militar em Vitória Antes do Ai-5

    Get PDF
    Partindo do pressuposto que o projeto civil-burguês-militar foi bem sucedido no Espírito Santo, esse trabalho objetiva resgatar as memórias passadas nos quatro primeiros anos de intervenção militar (1964-1968) em Vitória, de forma a fazer um registro da memória desse período de acordo com fontes orais e documentais que demonstrem como e quais os grupos de poder locais interagiram com o período, ou até contribuíram para sua radicalização que culminou com a decretação do Quinto Ato Institucional. Dentro desta problemática, a pesquisa se propõe apontar as particularidades e semelhanças da história capixaba em relação à história nacional, analisando a influência mútua trocada por esses dois lados

    Solid phase microextraction techniques used for gas chromatography: A review

    Get PDF
    In the last decade, the development and adoption of greener and sustainable microextraction techniques have been proved to be an effective alternative to classical sample preparation procedures. In this review, 10 commercially available solid-phase microextraction systems are presented, with special attention to the appraisal of their analytical, bioanalytical, and environmental engineering. This review provides an overview of the challenges and achievements in the application of fully automated miniaturized sample preparation methods in analytical laboratories. Both theoretical and practical aspects of these environment-friendly preparation approaches are discussed. The application of chemometrics in method development is also discussed. We are convinced that green analytical chemistry will be really useful in the years ahead. The application of cheap, fast, automated, clever , and environmentally safe procedures to environmental, clinical, and food analysis will improve significantly the quality of the analytical data

    Liquid phase microextraction techniques combined with chromatography analysis: A review

    Get PDF
    Sample pretreatment is the first and the most important step of an analytical procedure. In routine analysis, liquid-liquid microextraction (LLE) is the most widely used sample pre-treatment technique, whose goal is to isolate the target analytes, provide enrichment, with cleanup to lower the chemical noise, and enhance the signal. The use of extensive volumes of hazardous organic solvents and production of large amounts of waste make LLE procedures unsuitable for modern, highly automated laboratories, expensive, and environmentally unfriendly. In the past two decades, liquid-phase microextraction (LPME) was introduced to overcome these drawbacks. Thanks to the need of only a few microliters of extraction solvent, LPME techniques have been widely adopted by the scientific community. The aim of this review is to report on the state-of-the-art LPME techniques used in gas and liquid chromatography. Attention was paid to the classification of the LPME operating modes, to the historical contextualization of LPME applications, and to the advantages of microextraction in methods respecting the value of green analytical chemistry. Technical aspects such as description of methodology selected in method development for routine use, specific variants of LPME developed for complex matrices, derivatization, and enrichment techniques are also discussed

    The dark and the light side of the expatriate's cross-cultural adjustment: A novel framework including perceived organizational support, work related stress and innovation

    Get PDF
    The new context of the Psychology of Sustainability and Sustainable Development has reached the attention of the scientific community in recent years, due to its comprehensive approach aimed at enhancing the sustainability of interpersonal and intrapersonal talent, as well as of groups and communities. In this scenario, research on employee cross-cultural adjustment (CCA) is considered a key theme in human resource management. It is known that psychological support in the host country may alleviate distress and facilitate the integration of the expatriate workers. However, there is a lack of research investigating expatriate adjustment as an antecedent of the perceived organizational support. The aim of the study was to investigate the relationship among cross-cultural adjustment (CCA), perception of organizational support (POS), work-related stress (WRS), and innovation, considering these factors as a part of a unique innovative framework. A cross sectional study was performed using a sample of 234 expatriate workers of a multinational organization. Data were collected through a monitoring survey for the assessment of work-related stress risk factors of their expatriate staff. The results showed a positive correlation between CCA, POS, and innovation. On the other hand, a negative correlational effect of CCA and WRS, CCA and POS on WRS, and POS and WRS was found. Finally, POS was found to be a significant antecedent of CCA. These findings have implications for both international human resource management researchers and practitioners

    Postnatal Changes in K+/Cl- Cotransporter-2 Expression in the Forebrain of Mice Bearing a Mutant Nicotinic Subunit Linked to Sleep-Related Epilepsy

    Get PDF
    ABSTRACT The Na+/K+/Cl- cotransporter-1 (NKCC1) and the K+/Cl- cotransporter-2 (KCC2) set the transmembrane Cl- gradient in the brain, and are implicated in epileptogenesis. We studied the postnatal distribution of NKCC1 and KCC2 in wild-type (WT) mice, and in a mouse model of sleep-related epilepsy, carrying the mutant \u3b22-V287L subunit of the nicotinic acetylcholine receptor (nAChR). In WT neocortex, immunohistochemistry showed a wide distribution of NKCC1 in neurons and astrocytes. At birth, KCC2 was localized in neuronal somata, whereas at subsequent stages it was mainly found in the somatodendritic compartment. The cotransporters\u2019 expression was quantified by densitometry in the transgenic strain. KCC2 expression increased during the first postnatal weeks, while the NKCC1 amount remained stable, after birth. In mice expressing \u3b22-V287L, the KCC2 amount in layer V of prefrontal cortex (PFC) was lower than in the control littermates at postnatal day 8 (P8), with no concomitant change in NKCC1. Consistently, the GABAergic excitatory to inhibitory switch was delayed in PFC layer V of mice carrying \u3b22-V287L. At P60, the amount of KCC2 was instead higher in mice bearing the transgene. Irrespective of genotype, NKCC1 and KCC2 were abundantly expressed in the neuropil of most thalamic nuclei since birth. However, KCC2 expression decreased by P60 in the reticular nucleus, and more so in mice expressing \u3b22-V287L. Therefore, a complex regulatory interplay occurs between heteromeric nAChRs and KCC2 in postnatal forebrain. The pathogenetic effect of \u3b22-V287L may depend on altered KCC2 amounts in PFC during synaptogenesis, as well as in mature thalamocortical circuits

    The dark and the light side of the expatriate's cross-cultural adjustment: A novel framework including perceived organizational support, work related stress and innovation

    Get PDF
    The new context of the Psychology of Sustainability and Sustainable Development has reached the attention of the scientific community in recent years, due to its comprehensive approach aimed at enhancing the sustainability of interpersonal and intrapersonal talent, as well as of groups and communities. In this scenario, research on employee cross-cultural adjustment (CCA) is considered a key theme in human resource management. It is known that psychological support in the host country may alleviate distress and facilitate the integration of the expatriate workers. However, there is a lack of research investigating expatriate adjustment as an antecedent of the perceived organizational support. The aim of the study was to investigate the relationship among cross-cultural adjustment (CCA), perception of organizational support (POS), work-related stress (WRS), and innovation, considering these factors as a part of a unique innovative framework. A cross sectional study was performed using a sample of 234 expatriate workers of a multinational organization. Data were collected through a monitoring survey for the assessment of work-related stress risk factors of their expatriate staff. The results showed a positive correlation between CCA, POS, and innovation. On the other hand, a negative correlational effect of CCA and WRS, CCA and POS on WRS, and POS and WRS was found. Finally, POS was found to be a significant antecedent of CCA. These findings have implications for both international human resource management researchers and practitioners
    • …
    corecore