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Search Results: 1 - 10 of 329456 matches for " S.;Martinez "
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A LIBERDADE, A IGUALDADE E A FRATERNIDADE NA ANáLISE ECON MICA DO DIREITO A PARTIR DO PENSAMENTO DE AMARTYA SEN
Sérgio Rodrigo Martinez
Revista Científica Sensus : Direito , 2011,
Abstract: Amartya Sen, to study issues related to welfare economics, established new interdisciplinary contributions to ethics. One of the possible paths for your study in legal area occurs from the proposal of the economic analysis of law, undoing the concepts of traditional sciences and encompassing new possibilities in human development. Bring the Amartya Sen studies to the law research may enable transcend the new spheres of understanding of the phenomenon of the Welfare State and his search for production of collective welfare. This article seeks to highlight in which points to the contribution of the thought of Amartya Sen collaborates in this sense, to exalt the ethics present on freedom, equality and fraternity as fundamental factors for development.
Host-parasite interactions under extreme climatic conditions
J. MARTINEZ, S. MERINO
Current Zoology , 2011,
Abstract: The effect that climatic changes can exert on parasitic interactions represents a multifactor problem whose results are difficult to predict. The actual impact of changes will depend on their magnitude and the physiological tolerance of affected organisms. When the change is considered extreme (i.e. unusual weather events that are at the extremes of the historical distribution for a given area), the probability of an alteration in an organisms’ homeostasis increases dramatically. However, factors determining the altered dynamics of host-parasite interactions due to an extreme change are the same as those acting in response to changes of lower magnitude. Only a deep knowledge of these factors will help to produce more accurate predictive models for the effects of extreme changes on parasitic interactions. Extreme environmental conditions may affect pathogens directly when they include free-living stages in their life-cycles and indirectly through reduced resource availability for hosts and thus reduced ability to produce efficient anti-parasite defenses, or by effects on host density affecting transmission dynamics of diseases or the frequency of intraspecific contact. What are the consequences for host-parasite interactions? Here we summarize the present knowledge on three principal factors in determining host-parasite associations; biodiversity, population density and immunocompetence. In addition, we analyzed examples of the effects of environmental alteration of anthropogenic origin on parasitic systems because the effects are analogous to that exerted by an extreme climatic change [Current Zoology 57 (3): 390–405, 2011].
Ergodic Properties of Infinite Harmonic Crystals: an Analytic Approach
S. Graffi,A. Martinez
Physics , 1996, DOI: 10.1063/1.531741
Abstract: We give through pseudodifferential operator calculus a proof that the quantum dynamics of a class of infinite harmonic crystals becomes ergodic and mixing with respect to the quantum Gibbs measure if the classical infinite dynamics is respectively ergodic and mixing with respect to the classical infinite Gibbs measure. The classical ergodicity and mixing properties are recovered as $\hbar\to 0$, and the infinitely many particles limits of the quantum Gibbs averages are proved to be the averages over a classical infinite Gibbs measure of the symbols generating the quantum observables under Weyl quantization.
q-Thermodynamics: First law for quasi-stationary states
S. Martinez,A. Plastino
Physics , 2003,
Abstract: We discuss peculiar aspects of the first law of thermodynamics for systems characterized by the presence of meta-equilibrium quasi-stationary states for which the pertinent phase/configuration spaces is generally inhomogeneous. As a consequence, the naive additivity requirement for thermodynamic quantities ceases to be satisfied.
Time Aperiodic Perturbations of Integrable Hamiltonian Systems
A. Martinez,S. Wiggins
Physics , 2000,
Abstract: We consider a Hamiltonian $H=H^{0}(p)+\kappa H^{1}(p,q,t)$, $(p,q)\in {\mathbb{R}}^{n} \times {\mathbb{T}}^n$, $t\in{\mathbb{R}}$ where $\kappa \in {\mathbb{R}}$ is a small perturbation parameter and $p$, $q$ are the action and angle variables respectively. The Hamiltonian generates an autonomous vector field obtained by extending the phase space making $t$ a dependent variable and adding its conjugate variable $\tau$. In this paper we look at a time aperiodic perturbation $H^{1}(p,q,t)$ which tends as $t\to \infty$ to either a time independent perturbation or a time quasiperiodic perturbation and we prove a KAM-type theorem. Extending the phase space results in the preservation under a small enough perturbation of cylinders of the extended autonomous system rather than the usual tori. To prove the theorem we transform the Hamiltonian $H$ to a normal form which depends on fewer angles, none if possible. This transformation is done via a near identity canonical transformation. The canonical transformation is constructed using the Lie series formalism and by solving for a generating function. Because of the aperiodic time dependence, the usual Fourier series methods used to obtain the generating function no longer apply. Instead, we use Fourier transform methods to solve for the generating function and make use of an isoenergetic non-degeneracy condition which results in a shift of frequencies associated with each cylinder.
Asymptotic velocity of one dimensional diffusions with periodic drift
P. Collet S. Martinez
Mathematics , 2007,
Abstract: We consider the asymptotic behaviour of the solution of one dimensional stochastic differential equations and Langevin equations in periodic backgrounds with zero average. We prove that in several such models, there is generically a non vanishing asymptotic velocity, despite of the fact that the average of the background is zero.
Characterization of Local Configuration Controllability for a Class of Mechanical Systems
J. Cortes,S. Martinez
Mathematics , 2000,
Abstract: We investigate local configuration controllability for mechanical control systems within the affine connection formalism. Extending the work by Lewis for the single-input case, we are able to characterize local configuration controllability for systems with $n$ degrees of freedom and $n-1$ input forces.
Evaluation of Stable Isotopes of Water to Determine Rainwater Infiltration in Soils under Conservation Reserve Program  [PDF]
Timothy S. Goebel, Robert J. Lascano, Veronica Acosta-Martinez
Journal of Agricultural Chemistry and Environment (JACEN) , 2016, DOI: 10.4236/jacen.2016.54019
Abstract: The Conservation Reserve Program (CRP) is a USDA program introduced in 1985 to reduce soil erosion by increasing vegetative cover of highly erodible land. Participation in the CRP is done via contracts (10 - 15 years in length) and currently the total area of land under contract is set to decline as per the 2014 Farm Bill. The Texas High Plains (THP) leads the US with >900,000 ha enrolled in CRP. A potential long- term benefit of CRP is to increase soil organic matter and to improve soil structure leading to increased water infiltration. Our objective was to evaluate the feasibility of using stable isotopes of water to measure and compare infiltration of rain in land under CRP management to land under continuous dryland cotton in the THP. For this purpose we selected two sites, with soils in the Amarillo series, enrolled in CRP, one for 25 years and the second site for 22 years. Results from several rain events showed that stable isotopes of water are a method that can be used to evaluate the depth of rainwater infiltration for soils under CRP and dryland management.
Increase in water column denitrification during the last deglaciation: the influence of oxygen demand in the eastern equatorial Pacific
P. Martinez,R. S. Robinson
Biogeosciences (BG) & Discussions (BGD) , 2010,
Abstract: Here we present organic export production and nitrogen isotope results spanning the last 30 000 years from a core recovered off Costa Rica (Ocean Drilling Program (ODP) Site 1242) on the leading edge of the oxygen minimum zone of the Eastern Tropical North Pacific. Marine export production reveals glacial-interglacial variations with low organic matter (total organic carbon and total nitrogen) contents during warm intervals, twice more during cold episodes and double peaked maximum during the deglaciation, between ~15.5–18.5 and 11–13 ka B.P. When this new export production record is compared with four nearby cores from within the Eastern Pacific along the Equatorial divergence, good agreement between all the cores is observed. The major feature is a maximum of export during the early deglaciation. As for export production, water-column denitrification, represented by sedimentary δ15N records, along the Eastern tropical North and South Pacific between 15° N and 36° S is also coherent over the last deglaciation. Each of the nitrogen isotope profiles indicate that denitrification increased abruptly at 19 ka B.P to a maximum during the early deglaciation, confirming a typical Antarctic timing. It is proposed that the increase in export production and then in subsurface oxygen demand lead to an intensification of water-column denitrification within the oxygen minimum zones in the easternmost Pacific at the time of the last deglaciation. The triggering mechanism would have been primarily linked to an increase in preformed nutrients contents feeding the Equatorial Undercurrent driven by the resumption of overturning in the Southern Ocean and the return of nutrients from the deep ocean to the sea-surface. An increase in equatorial wind-driven upwelling of sub-surface nutrient-rich waters could have played the role of an amplifier.
Increase in water column denitrification during the deglaciation controlled by oxygen demand in the eastern equatorial Pacific
P. Martinez,R. S. Robinson
Biogeosciences Discussions , 2009,
Abstract: Here we present organic export production and isotopic nitrogen results over the last 30 000 years from one core localized off Costa Rica (ODP Site 1242) on the leading edge of the oxygen minimum zone of the Eastern Tropical North Pacific. Marine export production reveals glacial-interglacial variations with low organic matter (total organic carbon and total nitrogen) contents during warm intervals, twice more during cold episodes and double peaked maximum during the deglaciation, between ~15.5–18.5 and 11–13 ka BP. When this new export production record is compared with four nearby cores localized within the Eastern Pacific along the Equatorial divergence, a good agreement between all the cores is observed, with the major feature being a maximum of export during the early deglaciation. As for export production, water-column denitrification represented by sedimentary δ15N records along the Eastern tropical North and South Pacific between 15° N and 36° S is coherent as well over the last deglaciation period. The whole isotopic nitrogen profiles indicate that denitrification increased abruptly at 19 ka BP to a maximum during the early deglaciation, confirming a typical Antarctic timing. It is proposed that the increase in export production and then in subsurface oxygen demand lead to an intensification of water-column denitrification within the oxygen minimum zones in the easternmost Pacific at the time of the last deglaciation. The triggering mechanism would have been primarily linked to an increase in preformed nutrients contents feeding the Equatorial Undercurrent driven by the resumption of overturning in the Southern Ocean and the return of nutrients from the deep ocean to the sea-surface. An increase in equatorial wind-driven upwelling of sub-surface nutrient-rich waters could have played the role of an amplifier.
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