3,049 research outputs found
Simulating the formation and evolution of galaxies with EvoL, the Padova N-body Tree-SPH Code
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
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 m CH bands and evidence for carbon monoxide
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
m range, using CRIRES at the VLT.
We obtain (i) the first detection of gaseous methane in this spectral range,
through lines of the + and + bands (ii) strong
evidence (6- confidence) for gaseous CO in Pluto. For an isothermal
atmosphere at 90 K, the CH 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 CH and CO mixing ratios q=
0.6% (consistent with results from the 1.66 m range) and
q = 0.5. 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.
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
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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