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Search Results: 1 - 10 of 237832 matches for " Mario R. Perez "
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La encopresis como manifestación de trastornos psíquicos en el ni o
Revista chilena de pediatría , 1973,
A Maximum-Likelihood Analysis of Observational Data on Fluxes and Distances of Radio Pulsars: Evidence for Violation of the Inverse-Square Law
John Singleton,Pinaki Sengupta,John Middleditch,Todd L. Graves,Mario R. Perez,Houshang Ardavan,Arzhang Ardavan
Physics , 2009,
Abstract: We analyze pulsar fluxes at 1400 MHz ($S_{1400}$) and distances ($d$) extracted from the Parkes Multibeam Survey. Under the assumption that distribution of pulsar luminosities is distance-independent, we find that either (a) pulsar fluxes diminish with distance according to a non-standard power law, due, we suggest, to the presence of a component with $S_{1400} \propto 1/d$, or (b) that there are very significant (i.e. order of magnitude) errors in the dispersion-measure method for estimating pulsar distances. The former conclusion (a) supports a model for pulsar emission that has also successfully explained the frequency spectrum of the Crab and 8 other pulsars over 16 orders of magnitude of frequency, whilst alternative (b) would necessitate a radical re-evaluation of both the dispersion-measure method and current ideas about the distribution of free electrons within our Galaxy.
Scientific Objectives for UV/Visible Astrophysics Investigations: A Summary of Responses by the Community (2012)
Paul A. Scowen,Mario R. Perez,Susan G. Neff,Dominic J. Benford
Physics , 2013, DOI: 10.1007/s10686-013-9363-0
Abstract: Following several recommendations presented by the Astrophysics Decadal Survey 2010 centered around the need to define "a future ultraviolet-optical space capability," on 2012 May 25, NASA issued a Request for Information (RFI) seeking persuasive ultraviolet (UV) and visible wavelength astrophysics science investigations. The goal was to develop a cohesive and compelling set of science objectives that motivate and support the development of the next generation of ultraviolet/visible space astrophysics missions. Responses were due on 10 August 2012 when 34 submissions were received addressing a number of potential science drivers. A UV/visible Mission RFI Workshop was held on 2012 September 20 where each of these submissions was summarized and discussed in the context of each other. We present a scientific analysis of these submissions and presentations and the pursuant measurement capability needs, which could influence ultraviolet/visible technology development plans for the rest of this decade. We also describe the process and requirements leading to the inception of this community RFI, subsequent workshop and the expected evolution of these ideas and concepts for the remainder of this decade.
Technico-Economical Evaluation of CO2 Transport in an Adsorbed Phase  [PDF]
Mildred Lemus Perez, Manuel Rodriguez Susa, Mario Pellerano, Arnaud Delebarre
Low Carbon Economy (LCE) , 2012, DOI: 10.4236/lce.2012.31004
Abstract: This work considers the possibility to transport CO2 in an adsorbed phase and analyzes its cost as a function of transported quantities, transport conditions and transportation means. CO2 adsorption capacities of 6 different adsorbents, comprising 4 activated carbons and 2 zeolites, were empirically evaluated in a given range of pressure and temperature. The adsorbent with the highest mass adsorption capacity (AC1), as well as another sorbent described in the literature (AC5) were selected to be used for CO2 transportation by ships, trains or trucks. Their characteristics and performances were then used to develop an economic analysis of transportation costs and CO2 emissions generated by the transport with or without storage. Economic evaluation of CO2 batch transport shows that CO2 transported in an adsorbed phase by train was seen to be almost competitive on distances between 250 and 500 km, in comparison to liquefied CO2. One of the activated carbon appeared to be competitive on short distances by truck when transport was not followed by storage. Ship transport of adsorbed CO2 on distances around 1500 km was competitive, when CO2 was used as delivered; there was an over cost of only 16%, when there was storage after the transport. The CO2 emissions generated by CO2 transport and storage when transport is carried out in an adsorbed phase were smaller than the ones generated by liquid phase transport below 1200 km, 500 km and 300 km by ship, train and truck respectively, as a function of the adsorbent used. Adsorbed CO2 transported on 1500 km by ship generated 27% less CO2 emissions than liquid phase and 17% by train for a distance of 250 km and 16% by truck on 150 km, although these differences were decreasing with the distance of transport.
Consideraciones sobre problemáticas del adolescente a través de la patología
Revista chilena de pediatría , 1973,
Modeling turbulent wave-front phase as a fractional Brownian motion: a new approach
Dario G. Perez,Luciano Zunino,Mario Garavaglia
Physics , 2004, DOI: 10.1364/JOSAA.21.001962
Abstract: This paper introduces a general and new formalism to model the turbulent wave-front phase using fractional Brownian motion processes. Moreover, it extends results to non-Kolmogorov turbulence. In particular, generalized expressions for the Strehl ratio and the angle-of-arrival variance are obtained. These are dependent on the dynamic state of the turbulence.
A fractional Brownian motion model for the turbulent refractive index in lightwave propagation
Dario G. Perez,Luciano Zunino,Mario Garavaglia
Physics , 2003, DOI: 10.1016/j.optcom.2004.08.007
Abstract: It is discussed the limitations of the widely used markovian approximation applied to model the turbulent refractive index in lightwave propagation. It is well-known the index is a passive scalar field. Thus, the actual knowledge about these quantities is used to propose an alternative stochastic process to the markovian approximation: the fractional Brownian motion. This generalizes the former introducing memory; that is, there is correlation along the propagation path.
German E Perez R
Revista Facultad de Medicina de la Universidad Nacional de Colombia , 2011,
Cyanobacterial Toxins as Allelochemicals with Potential Applications as Algaecides, Herbicides and Insecticides
John P. Berry,Miroslav Gantar,Mario H. Perez,Gerald Berry
Marine Drugs , 2008,
Abstract: Cyanobacteria ( ¢ € blue-green algae ¢ € ) from marine and freshwater habitats are known to produce a diverse array of toxic or otherwise bioactive metabolites. However, the functional role of the vast majority of these compounds, particularly in terms of the physiology and ecology of the cyanobacteria that produce them, remains largely unknown. A limited number of studies have suggested that some of the compounds may have ecological roles as allelochemicals, specifically including compounds that may inhibit competing sympatric macrophytes, algae and microbes. These allelochemicals may also play a role in defense against potential predators and grazers, particularly aquatic invertebrates and their larvae. This review will discuss the existing evidence for the allelochemical roles of cyanobacterial toxins, as well as the potential for development and application of these compounds as algaecides, herbicides and insecticides, and specifically present relevant results from investigations into toxins of cyanobacteria from the Florida Everglades and associated waterways.
Characterization of Laser Propagation Through Turbulent Media by Quantifiers Based on the Wavelet Transform
Luciano Zunino,Dario G. Perez,Osvaldo A. Rosso,Mario Garavaglia
Physics , 2003, DOI: 10.1142/S0218348X04002471
Abstract: The propagation of a laser beam through turbulent media is modeled as a fractional Brownian motion (fBm). Time series corresponding to the center position of the laser spot (coordinates x and y) after traveling across air in turbulent motion, with different strength, are analyzed by the wavelet theory. Two quantifiers are calculated, the Hurst exponent and the mean Normalized Total Wavelet Entropy. It is verified that both quantifiers gives complementary information about the turbulence state.
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