572 research outputs found

    Lensing Magnification and QSO-Galaxy Cross-Correlations: Observations, Theory and Simulations

    Full text link
    We review observations and gravitational lensing theory related to the magnification of background QSOs by intervening overdensities, and the induced cross-correlation between sources and foreground galaxies. We pay special attention to simulations, and present some preliminary results from high resolution cluster simulations, which show the role of the halo core and substructure on non-linear magnification. For massive clusters, deviations from the weak gravitational lensing regime are significant on arcmin scales and bellow. The accumulated knowledge in the field already shows that gravitational lensing magnification is an important astrophysical and cosmological tool.Comment: 6 pages. Presented at "100 years of relativity -- international conference on classical and quantum aspects of gravity and cosmology", 200

    Cosmological model differentiation through weak gravitational lensing

    Get PDF
    We investigate the potential of weak gravitational lensing maps to differentiate between distinct cosmological models, considering cosmic variance due to a limited map extension and the presence of noise. We introduce a measure of the differentiation between two models under a chosen lensing statistics. That enables one to determine in which circumstances (map size and noise level), and for which lensing measures two models can be differentiated at a desired confidence level. As an application, we simulate convergence maps for three cosmological models (SCDM, OCDM, and Λ\LambdaCDM), calculate several lensing analyses for them, and compute the differentiation between the models under these analyses. We use first, second, and higher order statistics, including Minkowski functionals, which provide a complete morphological characterization of the lensing maps. We examine for each lensing measure used how noise affects its description of the convergence, and how this affects its ability to differentiate between cosmological models. Our results corroborate to the valuable use of weak gravitational lensing as a cosmological tool.Comment: 12 pages, 8 figures. Submitted to MNRA

    A hydro-geochemical analysis of the saturation process with salt water of a bentonite crushed granite rock mixture in an engineered nuclear barrier

    Get PDF
    A MX-80 sodium bentonite crushed granite rock mixture is being saturated in the Äspö Hard Rock Laboratory managed by SKB (the Swedish Company of nuclear waste management) as part of the “Backfill and Plug Test Project”. The Äspö Hard Rock Laboratory is placed in the Swedish Island of Äspö, an underground full-scale laboratory where different testing construction procedures and handling techniques are being studied. The groundwater of Äspö has a variable salt concentration according to the zone considered. The added water during the mixing process of both materials had an average salt concentration of 6 g/L. However, backfill is being saturated with salt water containing higher salt content (up to 16 g/L, 50 / 50 of NaCl and CaCl2 by mass) to speed up the saturation process. The mixture swelling capacity is small due to the low backfill bentonite content, but its activity is still large if compared with natural clayey soils. A coupled hydro-chemical approach was used to simulate the backfill hydration process, comparing the results with in situ measurements. An intrinsic permeability law, depending on salt concentration in the liquid phase, was incorporated into the model. The retention curve was also determined taking into account the effect of the chemical species on backfill behaviour. The simulation of the saturation process shows the importance of studying these problems with a HC (hydro-chemical) formulation, especially if long term behaviour of such mixtures is going to be reproduced

    Workplace Learning Strategies and Professional Competencies in Innovation Contexts in Brazilian Hospitals

    Get PDF
    Competencies mobilized by service providers form an element of hospital services insofar as scientific and technological procedures that are part of the service become tangible. In view of the fact that hospitals have adopted Information and Communication Technologies (ICT), it would be logical to assume that learning contributes towards acquiring competencies related to changes in hospitals resulting from the adoption of new technologies. This paper aims to analyze relationships between workplace learning strategies and professional competencies after the adoption of innovations supported ICT in hospitals. Eleven interviews were carried out with professionals from three different hospitals and identifying the professional competencies resulting from innovations supported by ICT. This was followed by a cross-sectional survey involving 425 employees at the hospitals surveyed. The data analysis was undertaken by means of structural equation modeling (SEM). The results confirm the hypothesis and indicate that the performance of professional competences based on new ICT is determined by the way the respondents think, change and apply their knowledge, skills and attitudes in the workplace by use of new information and communication technologies

    α-particle production in 6He + 120Sn collisions

    Get PDF
    The collision 6He+120Sn has been investigated at four energies near the Coulomb barrier. A large yield of α particles has been detected, with energies around the energy of the scattered 6He beam. The energy and angular distributions of the α particles have been analyzed and compared with breakup and neutron transfer calculations.Ministerio de Ciencia e Innovación (España) FPA2006-13807-c02-01Junta de Andalucía P07-FQM-02894Ministerio de Educación y Ciencia (España) PCI2006-A7-0654Programa Consolider-Ingenio 2010 (España) CSD2007-0004

    Patologia dos anexos oculares

    Get PDF
    Os principais temas da patologia dos anexos oculares foram revistos, com ênfase nas patologias que pertencem ao campo de atuação da oculoplástica.The main topics of the adnexal ocular pathology were reviewed with emphasis in the pathologic conditions that belong to the oculoplastic field
    • …
    corecore