3,049 research outputs found

    Simulating the formation and evolution of galaxies with EvoL, the Padova N-body Tree-SPH Code

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    The importance of numerical simulations in astrophysics is constantly growing, because of the complexity, the multi-scaling properties and the non-linearity of many physical phenomena. In particular, cosmological and galaxysized simulations of structure formation have cast light on different aspects, giving answers to many questions, but raising a number of new issues to be investigated. Over the last decade, great effort has been devoted in Padova to develop a tool explicitly designed to study the problem of galaxy formation and evolution, with particular attention to the early-type ones. To this aim, many simulations have been run on CINECA supercomputers (see publications list below). The next step is the new release of EvoL, a Fortran N-body code capable to follow in great detail many different aspects of stellar, interstellar and cosmological physics. In particular, special care has been paid to the properties of stars and their interplay with the surrounding interstellar medium (ISM), as well as to the multiphase nature of the ISM, to the setting of the initial and boundary conditions, and to the correct description of gas physics via modern formulations of the classical Smoothed Particle Hydrodynamics algorithms. Moreover, a powerful tool to compare numerical predictions with observables has been developed, self-consistently closing the Whole package. A library of new simulations, run with EvoL on CINECA supercomputers, is to be built in the next years, while new physics, including magnetic properties of matter and more exotic energy feedback effects, is to be added

    Tuberculosis Drugs Supervisior Roles Improved the TB Recovery at The Community Health Center in Kupang City

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    Tuberculosis is a chronic and infectious disease that is still a major public health problem. The spread of this disease is caused by contact with infected droplets. The strategy of the tuberculosis control program in Indonesia uses the directly observed treatment short-course (DOTS) strategy in which patients will be sought and treated until they are cured. Every patient also needs Drug Drink Supervisor (called PMO) who can be nurses, midwives, family members, and health cadres. The role of the TB Drugs Drink Supervisor that has been described in many studies can increase the cure rate by up to 80%. The purpose of this study was to identify the relationship between the role of PMO in the recovery of tuberculosis patients. This research was a cross-sectional research design. Purposive sampling was used to determine the 96 tuberculosis patients who had completed the treatment program. The chi-square was used to identify the relationship between the variables. The study found that there is a relationship between the role of TB drug supervisors (conducting home visits, accompaniment during anti-tuberculosis drug swallowing, providing health education, encouragement of sputum re-checking, and accompaniment during taking anti-tuberculosis drugs in public health centers) with patient recovery (p=0.000). When the TB Drug Drink Supervisor performed well in all roles, it will motivate the TB patients to follow the treatment recommendation and facilitate TB recovery

    High resolution spectroscopy of Pluto's atmosphere: detection of the 2.3 μ\mum CH4_4 bands and evidence for carbon monoxide

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    The goal is to determine the composition of Pluto's atmosphere and to constrain the nature of surface-atmosphere interactions. We perform high--resolution spectroscopic observations in the 2.33--2.36 μ\mum range, using CRIRES at the VLT. We obtain (i) the first detection of gaseous methane in this spectral range, through lines of the ν3\nu_3 + ν4\nu_4 and ν1\nu_1 + ν4\nu_4 bands (ii) strong evidence (6-σ\sigma confidence) for gaseous CO in Pluto. For an isothermal atmosphere at 90 K, the CH4_4 and CO column densities are 0.75 and 0.07 cm-am, within factors of 2 and 3, respectively. Using a physically--based thermal structure model of Pluto's atmosphere also satisfying constraints from stellar occultations, we infer CH4_4 and CO mixing ratios qCH4_{CH_4}= 0.60.3+0.6^{+0.6}_{-0.3}% (consistent with results from the 1.66 μ\mum range) and qCO_{CO} = 0.50.25+1^{+1}_{-0.25}×103\times10^{-3}. The CO atmospheric abundance is consistent with its surface abundance. As for Triton, it is probably controlled by a thin, CO-rich, detailed balancing layer resulting from seasonal transport and/or atmospheric escape.Comment: Astronomy and Astrophysics Letters, in pres

    Perfect drain for the Maxwell Fish Eye lens.

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    Perfect imaging of electromagnetic waves using the Maxwell fish eye (MFE) requires a new concept: a point called the perfect drain that we shall call the perfect point drain. From the mathematical point of view, a perfect point drain is just like an ideal point source, except that it drains power from the electromagnetic field instead of generating it. We introduce here the perfect drain for the MFE as a dissipative region of non-zero size that completely drains the power from the point source. To accomplish this goal, the region must have a precise complex permittivity that depends on its size as well as on the frequency. The perfect point drain is obtained when the diameter of the perfect drain tends to zero. This interpretation of the perfect point drain is connected well with common concepts of electromagnetic theory, opening up both modeling in computer simulations and experimental verification of setups containing a perfect point drain

    EvoL: The new Padova T-SPH parallel code for cosmological simulations - I. Basic code: gravity and hydrodynamics

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    We present EvoL, the new release of the Padova N-body code for cosmological simulations of galaxy formation and evolution. In this paper, the basic Tree + SPH code is presented and analysed, together with an overview on the software architectures. EvoL is a flexible parallel Fortran95 code, specifically designed for simulations of cosmological structure formation on cluster, galactic and sub-galactic scales. EvoL is a fully Lagrangian self-adaptive code, based on the classical Oct-tree and on the Smoothed Particle Hydrodynamics algorithm. It includes special features such as adaptive softening lengths with correcting extra-terms, and modern formulations of SPH and artificial viscosity. It is designed to be run in parallel on multiple CPUs to optimize the performance and save computational time. We describe the code in detail, and present the results of a number of standard hydrodynamical tests.Comment: 33 pages, 49 figures, accepted on A&
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