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匹配条件: “Eduardo;” ,找到相关结果约22172条。
Optimal Stochastic Pine Stands Harvest Rotation Policies  [PDF]
Eduardo Navarrete
Open Journal of Forestry (OJF) , 2015, DOI: 10.4236/ojf.2015.56053
Abstract: A new Faustmann optimal rotation harvesting stands’ problem under Brown geometric price and Logistic and Gompertz wood stock, diffusions is presented. The optimal cut policies for the stochastic Faustmann model and the single harvest rotation or Vicksell model are evaluated in the case of a Chilean Radiata pine forest company. The company cut policy validates the Vicksell model, its optimal cut policies overestimate the company policy cut in 1.2%, in the Gompertz case, and underestimate it in 2.3%, in the Logistic case. The Faustmann optimal cut policies present a larger underestimation of the company cut policy in 10.1%, in the Gompertz case, and in 21.5%, in the Logistic case. The preference for shorter evaluation period that the company shows is due to the organizational risk that the forest economic sectors has in Chile.
Stress prevention by modulation of autonomic nervous system (heart rate variability): A preliminary study using transcranial direct current stimulation  [PDF]
Eduardo Manuel Gon?alves
Open Journal of Psychiatry (OJPsych) , 2012, DOI: 10.4236/ojpsych.2012.22016
Abstract: Introduction: Transcranial Direct Current Stimulation (tDCS) is a non-invasive, technique for brain stimulation. Anodal stimulation causes neuronal depolarisation and long-term potentiation, while cathodal stimulation causes hyperpolarisation and long-term depression. Stressors are associated with an increase in sympathetic cardiac control, a decrease in parasympathetic control, or both. Associated with these reactions is a frequently reported increase in Low Frequency (LF) Heart Rate Variability (HRV), a decrease in High Frequency (HF) power, and/or an increase in the LF/HF ratio. Objectives and aims: The present work aims to explore the tDCS potential in the modulation of the Autonomic Nervous System (ANS), through indirect stimulation of Anterior Cingulate Cortex (ACC). Methods: Two subjects, a 39 year old female and a 49 year old male, gave informed consent. Saline soaked synthetic sponges involving two, thick, metalic (stainless steel) rectangles, with an area of 25 cm2 each have been used as electrodes, connected to Iomed Phoresor II Auto device. It has been delivered a 2 mA current, for 20 minutes, over the left Dorsolateral Prefrontal Cortex (DLPFC) (Anode). Spectrum analysis (cStress software) of HRV has been performed before and after tDCS administration. Results: The female/male subject results of LF power, HF power and LF/HF ratio, before tDCS administration, were, respectively: 50.1 nu/60 nu, 46.1 nu/21.7 nu and 1.087/2.771; and, after tDCS administration, respectively: 33.5 nu/52.7 nu, 47.6 nu/ 22.8 nu and 0.704/2.312. Conclusions: tDCS over the left DLPFC (left ACC) increased parasympathetic activity and decreased sympathetic activity, suggesting the importance of tDCS in the management of stress-related disorders.
Has the 2009 Mexican Economic Crisis Been the Worst Ever?  [PDF]
Eduardo Loría
Modern Economy (ME) , 2013, DOI: 10.4236/me.2013.43A024

It has been widely accepted that in Mexico, the 2009 crisis has been the worst ever since The Great Depression (in the1930’s) with the only argument being the abrupt fall in GDP. Our main conclusion is that the 1995 crisis was more severe due to its further negative effects in all the other economic and social variables. In order to prove this hypothesis, a comparative analysis (using macroeconomic and social variables) with the 1983 and 1995 crises is made.

Efficiency of Portable Electronic Vulcanizer  [PDF]
Eduardo Zeta Ramis
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.31002
Abstract: This research was aimed at finding out the efficiency of the portable electronic vulcanizer. The old vulcanizing equipment was upgraded to save time, investment, manpower and to eliminate the problem of gas emission in vulcanization. The study also determined the accurate temperature setting and duration of vulcanizing process using electronic vulcanizer which eliminated the problem of gas emission produced by the conventional (gas fired) vulcanizer of about 2.772 kg of carbon dioxide for 1 liter of diesel fuel and/or 2.331 kg of carbon dioxide for 1 liter of petrol into the atmosphere. In constructing this vulcanizer, a letter G body configuration made of GI pipe with 31.5 cm long lag bolt with some electronic parts were installed, like the analog temperature gauge, digital timer, relay, LED, buzzer, switch, and heating element. Specifically, the product is divided into three components: base or body, control panel board and the heating unit. The effectiveness level of the equipment was tested utilizing five different temperatures at a constant and variable time. For Class A gum, the best temperature which bonded the gum exactly to the rubber tire was 60 in 1 minute while Class B gum was bonded at 60 in 2 minutes. The rate of energy consumed by the electronic vulcanizer for Class A gum was Php 0.0757 with an efficiency of 85.22% and for Class B gum was Php 0.15 with an efficiency of 85.22% and for conventional vulcanizer for Class A gum was Php 1.08 with an efficiency of 43.38% and for Class B gum was Php 1.52, with an efficiency of 78.08%. The study revealed that more tires could be vulcanized in a short period of time, therefore providing greater income over time. It is also environment-friendly since it does not emit carbon dioxide as compared to the conventional vulcanizing.
Proyecciones (Antofagasta) , 2001, DOI: 10.4067/S0716-09172001000200004
Abstract: recently an operation of graphs called substitution has been incorporated. in an informal way, the substitution consists in the replacement of a vertex for a graph. this new graph is characterized through a function (of substitution) that it could be self definable. the substitution of each vertex of a graph g, through injectives functions of substitution, by the same g graph will be called autosubstitution and denoted by g(g). if x represents the class of all the simple and finite graphs and w is an application of x in x, defined by w (g) = g (g), then it is interest in studying the dynamic properties of w and the construction of some algorithms that they permit the generating of fractal images. in function of the above-mentioned it is proposed to analyze the autosubstitution for graphs simple and finite. framed in the area of the graph dynamics, inside the area of the graph theory, the present work will use, preferably, simple and finite graph
Proyecciones (Antofagasta) , 2001,
Abstract: Recently an operation of graphs called substitution has been incorporated. In an informal way, the substitution consists in the replacement of a vertex for a graph. This new graph is characterized through a function (of substitution) that it could be self definable. The substitution of each vertex of a graph G, through injectives functions of substitution, by the same G graph will be called autosubstitution and denoted by G(G). If X represents the class of all the simple and finite graphs and w is an application of X in X, defined by w (G) = G (G), then it is interest in studying the dynamic properties of w and the construction of some algorithms that they permit the generating of fractal images. In function of the above-mentioned it is proposed to analyze the autosubstitution for graphs simple and finite. Framed in the area of the Graph Dynamics, inside the area of the Graph Theory, the present work will use, preferably, simple and finite graph
Swelling Properties of New Hydrogels Based on the Dimethyl Amino Ethyl Acrylate Methyl Chloride Quaternary Salt with Acrylic Acid and 2-Methylene Butane-1,4-Dioic Acid Monomers in Aqueous Solutions  [PDF]
Issa Katime, Eduardo Mendizábal
Materials Sciences and Applications (MSA) , 2010, DOI: 10.4236/msa.2010.13026
Abstract: Hydrogels of dimethylaminoethyl acrylate methyl chloride quaternary salt (Q9) have been synthesized with different monomer ratio by copolymerization of this poorly studied monomer either with acrylic acid or with 2-methylene bu-tane-1,4-dioic acid. Hydrogel swelling was measured as a function of the composition of the hydrogel and of the crosslinking agent ratio. High values of swelling have been obtained at very high crosslinking values (< 14 wt %) and the equilibrium swelling was reached at very low time (less than 15 minutes). The swelling isotherms consisted of a steep initial portion and then levelled off as asymptotically to the equilibrium swelling limit. The experimental data suggest clearly that the swelling process obeys second-order kinetics. According to this, the kinetics rate constant and the equilibrium water content were determined at different comonomer composition and crosslinker concentration. The calculated kinetic constants ranged from 0.48 to 3.76 × 10-2 min-1 for poly (acrylic acid-co-Q9) hydrogels and from 0.68 to 4.0 × 10-2 min-1 for poly (2-methylene butane-1,4-dioic acid-co-Q9) hydrogels depending on the hydrogels composition. The diffusion process was evaluated for each hydrogel showing a non-Fickian type diffusion. In all cases was observed a considerable increase in diffusion coefficient as Q9 content increases.
Institutions and Intellectuals That Configure the Concept of the Environment and Development in Latin America and Its Global Impact  [PDF]
Fernando Estenssoro, Eduardo Déves
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.49116

This paper is part of a research into the Latin American thinking on international affairs and a continuation of a line of work on Latin American contributions to the environmental discussion installed in the global political agenda in the early 70s. The premise was that Latin American contributions were initially made by professionals closely related to ECLAC, UNEP and the Bariloche Foundation. These professionals and agencies understood how poverty and backwardness were endured by the majority of the regional and world’s population was one of the main causes of environmental degradation; consequently, overcoming the environmental crisis meant that underdevelopment should be eradicated without delay. This view of the environmental problems was synthesized in the combined concept of environment and development, which was also understood in the region as “eco development”. Finally, the broad phenomenon they wanted to describe using the terms “environment and development” was summarized in the concept of sustainable development as defined in the 1987 World Commission on Environment and Development report “Our Common Future”.

La ecología política del giro biocéntrico en la nueva Constitución de Ecuador
Revista de Estudios Sociales , 2009,
Abstract: ecuador's new constitution is the frst in latin america to have a biocentric perspective. it introduces the concept of nature's rights together with the right to ecological restoration. it promotes a new articulation with traditional knowledge by referring to both nature and pachamama. and it provides a framework to base environmental policies and management on an andean perspective of the good life (sumak kawsay) and new kinds of development strategies. this paper describes and analyzes these new features from the perspective of political ecology and environmental ethics. it examines the impact of the concept of intrinsic value and offers a series of future challenges in feld of politics and management. the biocentric turn represents an alternative to modernity, making it possible to value nature, and articulate it with indigenous knowledge, in new ways.
Static Properties and Current-Driven Dynamics of Domain Walls in Perpendicular Magnetocrystalline Anisotropy Nanostrips with Rectangular Cross-Section
Eduardo Martinez
Advances in Condensed Matter Physics , 2012, DOI: 10.1155/2012/954196
Abstract: The current-induced domain wall motion along thin ferromagnetic strips with high perpendicular magnetocrystalline anisotropy is studied by means of full micromagnetic simulations and the extended one-dimensional model, taking into account thermal effects and edge roughness. A slow creep regime, where the motion is controlled by wall pinning and thermal activation, and a flow regime with linear variation of the DW velocity, are observed. In asymmetric stacks, where the Rashba spin-orbit field stabilizes the domain wall against turbulent transformations, the steady linear regime is extended to higher currents, leading to higher velocities than in single-layer or symmetric stacks. The pinning and depinning at and from a local constriction were also studied. The results indicate that engineering pinning sites in these strips provide an efficient pathway to achieve both high stability against thermal fluctuations and low-current depinning avoiding Joule heating. Finally, the current-driven dynamics of a pinned domain wall is examined, and both the direct and the alternating contributions to the induced voltage signal induced are characterized. It was confirmed that the direct contribution to the voltage signal can be linearly enhanced with the number of pinned walls, an observation which could be useful to develop domain-wall-based nano-oscillators. 1. Introduction A typical pattern of a ferromagnetic sample consist on a set of domains and domain walls (DWs). The domains are uniformly magnetized regions, and DWs constitute the boundary between them. DWs have been intensively researched in the past, both in bulk or continuous films [1]. However, as many other areas of physics, the study of DWs has been revitalized by the advent of nanotechnology, and at the present, modern nanolithograpy techniques allow the fabrication of suitable ultra-thin ferromagnetic strips where DWs can be easily nucleated. The development of advance microscopy methods has also permitted them to be imaged and their dynamics to be explored. The traditional way to promote the DW dynamics is done by applying magnetic fields. Recently, a more promising alternative to drive DWs has been proposed. It consists on flowing electrical currents though ferromagnetic strip by using the novel physics of spin-transfer torque. Electrical current passing through a ferromagnetic strip becomes spin polarized along the local magnetization direction. When the current crosses a DW, spin angular momentum is transferred from the current to the magnetization, thereby inducing a torque which leads to DW motion.

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