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Search Results: 1 - 10 of 580059 matches for " G. A. Raimondi "
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Intercambio gaseoso en el síndrome de dificultad respiratoria aguda
Raimondi,G. A.;
Medicina (Buenos Aires) , 2003,
Abstract: the hypoxemia of acute respiratory distress syndrome (ards) depends chiefly upon shunt and ventilation-perfusion (va/q) inequality produced by fluid located in the interstitial space, alveolar collapse and flooding. variables other than inspired oxygen fraction and the underlying physiological abnormality can influence arterial oxygen partial pressure (pao2). changes in cardiac output, hemoglobin concentration, oxygen consumption and alcalosis can cause changes in pao2 through their influence on mixed venous po2. gas exchange (ge) in ards may be studied using the inert gas elimination technique (miget) which enables to define the distribution of ventilation and perfusion without necessarily altering the fio2 differentiating shunt from lung units with low va/q ratios and dead space from lung units with high va/q ratios. different ventilatory strategies that increase mean airway pressure (positive end-expiratory pressure, high tidal volumes, inverse inspiratory-expiratory ratio, etc) improve pao2 through increasing lung volume by recruiting new open alveoli and spreading the intra-alveolar fluid over a large surface area. also prone-position ventilation would result in a marked improvement in ge enhancing dorsal lung ventilation by the effects on the gravitional distribution of pleural pressure and the reduction in the positive pleural pressure that develops in dorsal regions in ards. inhaled nitric oxide (no) has been shown to increase pao2 in ards patients by inducing vasodilation predominantly in ventilated areas redistributing pulmonary blood flow away from nonventilated toward ventilated areas of the lung thus resulting in a shunt reduction. on the same way inhaled prostaglandins (pgi2 or pge1) causes selective pulmonary vasodilation improving pulmonary ge. intravenous almitrine, a selective pulmonary vasoconstrictor, has been shown to increase pao2 by increasing hypoxic pulmonary vasoconstriction. a synergistic effect was found between inhaled no and almitrine.
Intercambio gaseoso en el síndrome de dificultad respiratoria aguda Gas exchange in acute respiratory distress syndrome
G. A. Raimondi
Medicina (Buenos Aires) , 2003,
Abstract: El síndrome de dificultad respiratoria aguda (ARDS) se caracteriza por presentar alteraciones severas del intercambio gaseoso (IG) causadas por shunt e importante irregularidad de la ventilación perfusión (V A/Q). Esto es consecuencia del edema intersticial y el colapso y ocupación alveolar. Además de la fracción inspirada de oxígeno y la evolución de la patología pulmonar, hay distintas variables que son capaces de alterar la presión parcial de oxígeno arterial (PaO2). Es así que los cambios del volumen minuto circulatorio, la concentración de hemoglobina, el consumo de oxígeno o la alcalosis pueden modificar la PaO2 a través de su influencia en la PO2 de sangre venosa mixta. A pesar de la influencia de estas diferentes variables, la anormalidad del IG se ha podido analizar adecuadamente por medio de la técnica de eliminación de múltiples gases inertes (MIGET). Asimismo, se han descripto diversas estrategias ventilatorias (presión positiva de fin de espiración, relaciones inspiratorias-espiratorias invertidas, volúmenes corrientes elevados, etc.) que producen mejoría del IG principalmente a través del aumento de la presión media en la vía aérea al reclutar áreas pulmonares previamente colapsadas. También el cambio de decúbito a posición ventral, por modificaciones en la distribución de presión pleural regional, disminuye el colapso alveolar con mejoría de la PaO2. Asimismo hay distintas intervenciones farmacológicas capaces de mejorar el IG tales como la administración de óxido nítrico (ON) o de prostaglandinas (PGI2 o PGE1) por vía inhalatoria. Estas producen vasodilatación de las áreas bien ventiladas aumentando el flujo cardíaco a ese nivel y disminuyendo relativamente el flujo por las áreas de shunt . La almitrina endovenosa, droga vasoconstrictora pulmonar, mejora el IG al aumentar la vasoconstricción hipóxica. Se ha demostrado efecto aditivo de la almitrina con la inhalación de ON. A pesar del efecto beneficioso de todas estas técnicas en la mejoría del IG en el ARDS, no se ha demostrado efecto beneficioso en la sobrevida. The hypoxemia of acute respiratory distress syndrome (ARDS) depends chiefly upon shunt and ventilation-perfusion (V A/Q) inequality produced by fluid located in the interstitial space, alveolar collapse and flooding. Variables other than inspired oxygen fraction and the underlying physiological abnormality can influence arterial oxygen partial pressure (PaO2). Changes in cardiac output, hemoglobin concentration, oxygen consumption and alcalosis can cause changes in PaO2 through their influence on mixed venous PO2. Gas exchang
Fluctuation-induced electric and thermal magnetotransport of superconductors in the quasiballistic regime
G. Savona,D. V. Livanov,R. Raimondi,A. A. Varlamov
Physics , 2002, DOI: 10.1140/epjb/e2003-00124-5
Abstract: This paper has been withdrawn by the author(s),
New Developments in Linear Colliders Final Focus Systems
P. Raimondi,A. Seryi
Physics , 2000,
Abstract: The length, complexity and cost of the present Final Focus designs for linear colliders grows very quickly with the beam energy. In the paper, a novel final focus system is presented and compared with the one proposed for NLC. This new design is simpler, shorter and cheaper, with comparable bandwidth, tolerances and tunability. Moreover, the length scales slower than linearly with energy allowing for a more flexible design which is applicable over a much larger energy range.
Seletividade de amonio-glufosinate isolado e em mistura com pyrithiobac-sodium em algodoeiro transgênico LL Selectivity of ammonium-glufosinate applied alone or in mixture with pyrithiobac sodium in transgenic LL cotton
G.B.P. Braz,R.S. Oliveira Jr,J. Constantin,M.A. Raimondi
Planta Daninha , 2012, DOI: 10.1590/s0100-83582012000400020
Abstract: Com a recente introdu o no Brasil de variedades transgênicas de algodoeiro que apresentam resistência ao amonio-glufosinate (LL ), há escassez de informa es tanto a respeito da seletividade de reaplica es desse herbicida, quanto no que se refere a misturas com outros herbicidas. Objetivou-se no presente trabalho avaliar a seletividade de aplica es sequenciais de amonio-glufosinate isolado e em associa o com pyrithiobac-sodium em algod o transgênico LL . Dessa forma, foi instalado um experimento em delineamento de blocos casualizados em arranjo fatorial (3x3)+1, empregando-se oito repeti es. O primeiro fator correspondeu à aplica o dos tratamentos amonio-glufosinate (500 g ha-1) e amonio-glufosinate + pyrithiobac-sodium (500 + 42 g ha-1 e 500 + 56 g ha-1). O segundo fator foi o número de aplica es sequenciais em pós-emergência do algodoeiro (uma, duas ou três). O tratamento adicional foi composto por testemunha sem aplica o de herbicida. A associa o do pyrithiobac-sodium ao amonio-glufosinate causou maiores níveis de fitointoxica o inicial, embora n o tenham havido mais sintomas duas semanas após as aplica es. A qualidade de fibra do algodoeiro n o foi influenciada por nenhum dos tratamentos herbicidas. O amonio-glufosinate isolado foi seletivo para o algod o LL em até três aplica es em pós-emergência. O algodoeiro apresentou ainda tolerancia a uma aplica o da mistura de amonio-glufosinate + pyrithiobac-sodium, e n o se observou qualquer efeito negativo sobre a produtividade de algod o em caro o. Due to the recent introduction of transgenic cotton varities with resistance to ammonium-glufosinate (LL ) in Brazil, there is a lack of information related both to the selectivity of sequential reapplications of ammonium-glufosinate and to tank mixture with other herbicides. This work aimed to evaluate the selectivity of sequential applications of ammonium-glufosinate isolated or in associations with pyrithiobac-sodium in LL cotton. A field experiment was installed in a randomized block design with eight replicates. Treatments were arranged in a factorial scheme (3x3)+1. The first factor consisted of herbicide treatments as follows: ammonium-glufosinate (500 g ha-1), ammonium-glufosinate + pyrithiobac-sodium (500 + 42 gha-1 and 500 + 56gha-1). The second factor was the number of sequential post-emergence applications (one, two, or three), and the additional treatment was a non-applied check. All treatments were manually kept free of weeds throughout the crop cycle. Associating pyrithiobac-sodium to ammonium-glufosinate increased initial crop inj
Selectivity of glyphosate in tank mixtures for RR soybean in sequential applications with mixtures only in the first or second application
Alonso, D.G;Constantin, J;Oliveira Jr, R.S;Biffe, D.F;Raimondi, M.A;Gemelli, A;Blainski, E;Carneiro, J.C;
Planta Daninha , 2010, DOI: 10.1590/S0100-83582010000400020
Abstract: tank mixtures among herbicides of different action mechanisms might increase weed control spectrum and may be an important strategy for preventing the development of resistance in rr soybean. however, little is known about the effects of these herbicide combinations on soybean plants. hence, two experiments were carried out aiming at evaluating the selectivity of glyphosate mixtures with other active ingredients applied in postemergence to rr soybean. the first application was carried out at v1 to v2 soybean stage and the second at v3 to v4 (15 days after the first one). for experiment i, treatments (rates in g ha-1) evaluated were composed by two sequential applications: the first one with glyphosate (720) in tank mixtures with cloransulam (30.24), fomesafen (125), lactofen (72), chlorimuron (12.5), flumiclorac (30), bentazon (480) and imazethapyr (80); the second application consisted of isolated glyphosate (480). in experiment ii, treatments also consisted of two sequential applications, but tank mixtures as described above were applied as the second application. the first one in this experiment consisted of isolated glyphosate (720). for both experiments, sequential applications of glyphosate alone at 720/480, 960/480, 1200/480 and 960/720 (expt. i) or 720/480, 720/720, 720/960 and 720/1200 (expt. ii) were used as control treatments. applications of glyphosate tank mixtures with other herbicides are more selective to rr soybean when applied at younger stages whereas applications at later stages might cause yield losses, especially when glyphosate is mixed with lactofen and bentazon.
Seletividade de cultivares de soja RR? submetidos a misturas em tanque de glyphosate + chlorimuron-ethyl associadas a óleo mineral e inseticidas
Maciel, C.D.G.;Amstalden, S.L.;Raimondi, M.A.;Lima, G.R.G.;Oliveira Neto, A.M.;Artuzi, J.P.;
Planta Daninha , 2009, DOI: 10.1590/S0100-83582009000400014
Abstract: the use of glyphosate for weed control in soybean rr? presents essential practical characteristics. however, although not allowed by the current brazilian legislation, the association with other herbicides has been increasing for species of difficult control, as well as the use of tank mixtures combined with insecticides and adjuvants. aiming to evaluate the selectivity of soybean rr? genotypes submitted to tank mixtures of the glyphosate formulations (polaris?, roundup ready? and roundup wg?) with chlorimuron-ethyl (classic?), and their associations with mineral oil (joint oil?) and novaluron insecticides (gallaxy 100 ec?), permethrin (piredan?) and methomyl (lannate br?), an experiment was conducted under field conditions at maracai -s?o paulo, during the 2006/2007 growing year. the experiment was arranged in a randomized complete block design with four replications, in a factorial scheme 16 x 4, with 16 representing the tank mixture associations of glyphosate formulations, mineral oil and insecticide, and the four genotypes monsoy 7210rr?, monsoy 7979rr?, brs245rr? and cd 214rr?. visual symptoms of initial intoxication in the genotypes studied were characterized by chlorosis and wrinkle in the leaves for all tank mixtures of glyphosate + chlorimuron-ethyl, associated or not with mineral oil, and novaluron, permethrin and methomyl insecticides .none of the tank mixtures promoted significant yield reductions for monsoy 7210rr?, monsoy 7979rr? and brs245rr? genotypes, and controlled ipomoea spp with satisfactory effectiveness, starting from 21 daa (days after application).
Spin current swapping and Hanle spin Hall effect in the two dimensional electron gas
Ka Shen,R. Raimondi,G. Vignale
Physics , 2015, DOI: 10.1103/PhysRevB.92.035301
Abstract: We analyze the effect known as "spin current swapping" (SCS) due to electron-impurity scattering in a uniform spin-polarized two-dimensional electron gas. In this effect a primary spin current $J_i^a$ (lower index for spatial direction, upper index for spin direction) generates a secondary spin current $J_a^i$ if $i \neq a$, or $J_j^j$, with $j\ne i$, if $i= a$. Contrary to naive expectation, the homogeneous spin current associated with the uniform drift of the spin polarization in the electron gas does not generate a swapped spin current by the SCS mechanism. Nevertheless, a swapped spin current will be generated, if a magnetic field is present, by a completely different mechanism, namely, the precession of the spin Hall spin current in the magnetic field. We refer to this second mechanism as Hanle spin Hall effect, and we notice that it can be observed in an experiment in which a homogeneous drift current is passed through a uniformly magnetized electron gas. In contrast to this, we show that an unambiguous observation of SCS requires inhomogeneous spin currents, such as those that are associated with spin diffusion in a metal, and no magnetic field. An experimental setup for the observation of the SCS is therefore proposed.
Theory of coupled spin-charge transport due to spin-orbit interaction in inhomogeneous two-dimensional electron liquids
K. Shen,R. Raimondi,G. Vignale
Physics , 2014, DOI: 10.1103/PhysRevB.90.245302
Abstract: Spin-orbit interactions in two-dimensional electron liquids are responsible for many interesting transport phenomena in which particle currents are converted to spin polarizations and spin currents and viceversa. Prime examples are the spin Hall effect, the Edelstein effect, and their inverses. By similar mechanisms it is also possible to partially convert an optically induced electron-hole density wave to a spin density wave and viceversa. In this paper we present a unified theoretical treatment of these effects based on quantum kinetic equations that include not only the intrinsic spin-orbit coupling from the band structure of the host material, but also the spin-orbit coupling due to an external electric field and a random impurity potential. The drift-diffusion equations we derive in the diffusive regime are applicable to a broad variety of experimental situations, both homogeneous and non-homogeneous, and include on equal footing "skew scattering" and "side-jump" from electron-impurity collisions. As a demonstration of the strength and usefulness of the theory we apply it to the study of several effects of current experimental interest: the inverse Edelstein effect, the spin-current swapping effect, and the partial conversion of an electron-hole density wave to a spin density wave in a two-dimensional electron gas with Rashba and Dresselhaus spin-orbit couplings, subject to an electric field.
Effective pseudopotential for energy density functionals with higher order derivatives
F. Raimondi,B. G. Carlsson,J. Dobaczewski
Physics , 2011, DOI: 10.1103/PhysRevC.83.054311
Abstract: We derive a zero-range pseudopotential that includes all possible terms up to sixth order in derivatives. Within the Hartree-Fock approximation, it gives the average energy that corresponds to a quasi-local nuclear Energy Density Functional (EDF) built of derivatives of the one-body density matrix up to sixth order. The direct reference of the EDF to the pseudopotential acts as a constraint that divides the number of independent coupling constants of the EDF by two. This allows, e.g., for expressing the isovector part of the functional in terms of the isoscalar part, or vice versa. We also derive the analogous set of constraints for the coupling constants of the EDF that is restricted by spherical, space-inversion, and time-reversal symmetries.
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