Scopo del testo e' introdurre i concetti base della fisica stellare, della fisica delle galassie e della cosmologia con approccio essenzialmente fisico. La prima parte presenta le tecniche ...osservative sia nella banda ottica, sia nelle alte frequenze e nella banda radio. La parte dedicata alle stelle discute modelli di struttura e l'evoluzione. La terza parte e' dedicata alle galassie, morfologia, formazione ed evoluzione, per giungere allo studio della distribuzione sulle grandi scale. La sezione di cosmologia presenta i modelli cosmologici relativistici, con la discussione del big-bang, inflazione, materia oscura, energia oscura. Il testo rappresenta la raccolta delle lezioni tenute dall'autore per i corsi introduttivi di astrofisica delle lauree specialistiche in Fisica e Astrofisica nei passati 30 anni, ma include elementi avanzati utili per corsi introduttivi di astrofisica nel dottorato in Fisica. Il testo e' anche stato utilizzato in forma preliminare da colleghi di altre sedi.
Understanding the interactions and propagations of high energy protons and heavy ions are essential when trying to estimate the biological effects of Galactic Cosmic Rays (GCR) and Solar Particle ...Events (SPE) on personnel in space. To be able to calculate the shielding properties of different materials and radiation risks, particle and heavy ion transport codes are needed. In all particle and heavy ion transport codes, the probability function that a projectile particle will collide within a certain distance
x in the matter depends on the total reaction cross sections, and the calculated partial fragmentation cross sections scale with the total reaction cross sections. It is therefore crucial that accurate total reaction cross section models are used in the transport calculations. In this paper, different models for calculating nucleon–nucleus and nucleus–nucleus total reaction cross sections are compared with each other and with measurements. The uncertainties in the calculations with the different models are discussed, as well as their overall performances with respect to the available experimental data. Finally, a new compilation of experimental data is briefly presented.
Consider a continuous-time Markov process with transition rates matrix Q in the state space Λ ⋃ {0}. In the associated Fleming-Viot process N particles evolve independently in Λ with transition rates ...matrix Q until one of them attempts to jump to state 0. At this moment the particle jumps to one of the positions of the other particles, chosen uniformly at random. When Λ is finite, we show that the empirical distribution of the particles at a fixed time converges as N → ∞ to the distribution of a single particle at the same time conditioned on not touching {0}. Furthermore, the empirical profile of the unique invariant measure for the Fleming-Viot process with N particles converges as N → ∞ to the unique quasistationary distribution of the one-particle motion. A key element of the approach is to show that the two-particle correlations are of order 1 / N.
By adapting to computations that are not so well-supported by general-purpose processors, reconfigurable systems achieve significant increases in performance. Such computational systems use ...high-capacity programmable logic devices and are based on processing units customized to the requirements of a particular application. A great deal of the research effort in this area is aimed at accelerating the solution of combinatorial optimization problems. Special attention in this context was given to the Boolean satisfiability (SAT) problem resulting in a considerable number of different architectures being proposed. This paper presents the state-of-the-art in reconfigurable hardware SAT satisfiers. The analysis and classification of existing systems has been performed according to such criteria as algorithmic issues, reconfiguration modes, the execution model, the programming model, logic capacity, and performance.
The addition of a gas-impermeable coating on the inside wall of a standard polyethylene terephthalate (PET) bottle has long been considered as a way to improve the packaging for beer, juice and ...carbonated soft drinks. We have developed a plasma-assisted deposition process suitable for the deposition of 100 nm thick, transparent, hydrogenated amorphous carbon (a-C:H) films on PET surfaces. The Sidel plasma technology uses an acetylene gas precursor and a microwave plasma, which allows us to obtain a high deposition rate of 60 nm/s necessary for industrial process flows. The a-C:H films provide a 50-fold reduction of the permeation rates of O
2. The composition, optical, structural and defect properties of the a-C:H films were characterized by Rutherford Back Scattering (RBS), Elastic Recoil Detection Analysis (ERDA), X-ray Photoelectron Spectroscopy (XPS), optical spectroscopy, Raman and Electron Paramagnetic Resonance (EPR).
Nutritherapy seeks to prevent or correct disease by the use of nutritional supplements including vitamins, trace elements, or macronutrients. This chapter of the “Les Entretiens du Carla” reviews the ...potential of nutritherapy for the prevention or improvement of sarcopenia, which is the progressive reduction in muscle mass and muscle strength prevalent in late-life. It is critical that we review nutrients and their potential to maintain muscle mass and strength which ultimately will help minimize falls and fractures among the older population. Evidence from randomized-controlled trials will be reviewed for muscle mass as well as important sarcopenia-related endpoints including lower extremity strength and function, as well as falls and fallrelated fractures. This chapter will focus on vitamin D as a compelling strategy with evidence for strength gain, fall and fracture prevention from double-blind randomized controlled trials. The other strategy discussed is increased protein intake although longer-term trials and evidence for clinically important endpoints are limited. Today, there is no consistent data on other micronutrients or macronutrients with an established potential to combat sarcopenia.
Water pollution is a critical global problem. The fixed- bed continuous adsorption column provides the most practical application in the industry for wastewater treatment. The mass transfer process ...in the column can be described using a mass balance differential equation, and a sorbate–adsorbent interaction rate equation. The objective of this work was to describe the mass transfer in an adsorption column, analyzing the differential equations of the process and their analytical solutions. A general rate equation with four parameters was proposed, adding a zero-order parameter. The general model was solved using Laplace Transform method. The model proposed was applied to describe the adsorption of hexavalent chromium on chitosan biopolymer. The theoretical solution found was satisfactory to estimate the experimental breakthrough curves, and the estimated parameters allowed to predict other curves with different operational conditions. The zero-order parameter added relates to the baseline height of the breakthrough curve. The general model proposed generalizes already known plug flow models based on a single rate equation. The present model uses the information obtained from the column and from the equilibrium batch isotherm, which constitutes a useful tool for describing the dynamic adsorption process and to make decisions on column design.
Frail older adults with ongoing care needs often require post-acute care (PAC) following acute hospitalization when not eligible for specific rehabilitation. Long-term outcomes of PAC in this patient ...group have not been reported for Switzerland so far. In the present report, we investigated 12-month mortality in regard to frailty status upon admission to PAC in a nursing home setting. In our sample of 140 patients (mean age 84 ±8.6 years) 4.3% were robust, 37.1% were pre-frail, 54.3% were frail and 4.3% were missing frailty status. Mortality at 12-months follow-up stratified by baseline frailty was 0% (robust), 11.5% (pre-frail) and 31.6% (frail). Kaplan-Meier analysis stratified by frailty status showed a decreased probability of 12-months survival for frail individuals compared to their pre-frail and robust counterparts (P = 0.0096). Being frail was associated with more than 4-fold increased odds of death at follow-up (OR 4.19; 95% CI 1.53–11.47).
Differential 3D shape retrieval Di Martino, J. Matías; Fernández, Alicia; Ayubi, Gastón A. ...
Optics and lasers in engineering,
07/2014, Volume:
58
Journal Article
Peer reviewed
We are presenting a differential three-dimensional (3-D) shape profiling method that is based on the combination of orthogonal fringe projection. It allows us to compute depth gradient maps in a fast ...and efficient manner. What we are demonstrating is that depth gradients can be computed in a simple way by measuring fringe deformation throughout a novel single-shot approach. We show the usefulness and potential applications of the proposed approach. Validation experiments are presented as well.
•We present a differential three-dimensional (3-D) shape profiling.•The proposed method is based on a single-shot fringe projection.•Depth gradients can be simply computed by measuring fringes deformation.•No calibration or color coding strategies are needed.•The proposed method can help on retrieving 3D features.
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