Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 12 )

2018 ( 33 )

2017 ( 31 )

2016 ( 24 )

Custom range...

Search Results: 1 - 10 of 10515 matches for " Alexandre Monkolski "
All listed articles are free for downloading (OA Articles)
Page 1 /10515
Display every page Item
Caracteriza o das condi es ambientais de um rio neotropical a partir da densidade, composi o e riqueza de taxa de invertebrados bênticos = Environmental conditions of a neo-tropical river featuring density, composition and taxa richness of bentic invertebrates
Roger Paulo Mormul,Sidnei Pressinatte Junior,Luiz Alberto Vieira,Alexandre Monkolski
Acta Scientiarum : Biological Sciences , 2009,
Abstract: As atividades antrópicas podem causar profundas altera es nas características físicas e químicas dos ambientes aquáticos, assim como na biota. Muitas espécies de invertebrados bent nicos podem auxiliar a indica o dessas altera es. No presente estudo, foi realizada a caracteriza o das condi es ambientais de diferentes pontos do rio 119, Campo Mour o, Paraná, Brasil. Para tanto, foram analisadas condi es físico-químicas da água e coletadas amostras do substrato do rio para análises físicas e biológicas. A densidade, acomposi o e a riqueza dos táxons de invertebrados bênticos encontrados foram utilizadas para diferenciar os pontos quanto às condi es de altera o ambiental. Mudan as na densidade, na composi o e na riqueza foram relatadas em todos os pontos de coleta,principalmente em locais a jusante de áreas alteradas antropicamente. Alguns táxons característicos de locais com boa qualidade de água foram registrados, mas em número inferior ao de táxons que indicam altera es ambientais. Por ser um rio que corta longitudinalmente o perímetro urbano, ele sofre press o antrópica contínua, e a distribui o dos organismos ao longo desse gradiente provavelmente está respondendo às altera es ocorridas em cada local de coleta. Dessa forma, sugere-se a implementa o imediata de um plano de manejo e recupera o para todo o rio ao longo do perímetro urbano. Anthropic activities cause changes in physical and chemical characteristics in aquatic environments, as well as in the biotic component, and several benthic invertebrates species may indicate these changes. In this paper, we characterized the environmental conditions of different sample points in the 119 River, Campo Mour o, State of Paraná, Brazil. Physical and chemical conditions wereanalyzed in water, and samples of the river substrate were collected for physical and biological analysis. Density, composition and taxa richness of benthic invertebrates were used to distinguish the sampling points according to environmental changes. Alterations indensity, composition and richness were reported at all sampling points and samplings, mainly in sites downstream from areas with anthropic changes. Some characteristic taxa of locals with good water quality were recorded, but in smaller numbers compared with taxa that indicate environmental changes. Because the river crosses the urban area, it suffers continuous anthropic pressure and organism distribution throughout this gradient responds to the changes that occur in each sampling point. Thus, our results suggest that animmediate management plan is necessary to
Sucess o de invertebrados durante o processo de decomposi o de duas plantas aquáticas (Eichhornia azurea e Polygonum ferrugineum) = Succession of invertebrates during the decomposition process of two aquatic plants (Eichhornia azurea and Polygonum ferrugineum)
Roger Paulo Mormul,Luiz Alberto Vieira,Sidnei Pressinatte Júnior,Alexandre Monkolski
Acta Scientiarum : Biological Sciences , 2006,
Abstract: A coloniza o de invertebrados durante o período de 56 dias de decomposi o de duas espécies de plantas aquáticas (Eichhornia azurea e Polygonum ferrugineum) foi investigada para determinar o papel de macroinvertebrados no processo de fragmenta o da folha. Durante aanálise do material, foi constatado um total de 2096 invertebrados, associados a E.azurea e 6154 invertebrados associados a P. ferrugineum, identificados dentro de 18 táxons, com predominanciade larvas de Diptera da família Chironomidae, seguido por espécimes de Oligochaeta, microcrustáceos como Cladocera e Copepoda. Em ambas as plantas, os macroinvertebrados mostraram um aumento significativo de densidade ao longo do processo de decomposi o, o que provavelmente está associado à perda de compostos fenólicos. Os resultados sugerem que as espécies de macrófitas apresentam associa es específicas com seus consumidores, ou seja, o processo de sucess o da coloniza o torna-se diferenciado de acordo com as características fenológicas da planta. The invertebrate colonization was investigated during 56-day decomposition of two macrophytes species (Eichhornia azurea andPolygonum ferrugineum). The aim was to determine the role of macroinvertebrates in the process of leaf fragmentation. During material analysis, 2096 invertebrates were associated with E.azureaand 6154 were associated with P. ferrugineum, identified in 18 taxons, with predominance of Diptera larvae (Chironomidae family specially), followed by Oligochaeta species and microcrustaceans such as Cladocera and Copepoda. In both macrophytes the macroinvertebratesshowed a significant increase of density through the process of decomposition, which is probably associated with the loss of phenolic compounds. Results suggest that macrophytes specimens show specific associations with their consumers, i.e., the succession process of colonization becomes singular according to the phenolic characteristics of the plant.
Alexandre Monkolski, Janet Higuti, Luiz Alberto Vieira, Roger Paulo Mormul e Sidnei Pressinatte Junior
SaBios : Revista de Saúde e Biologia , 2006,
Abstract: The pollutant substance poured in the environment causes negative impacts for life forms that inhabit the sources. The biological monitoring of aquatic ecosystems has as objective the evaluation of the quality of water, in function of alterations of the community of macroinvertebrates. Among these communities Benthic is distinguished, because it reflects the state of conservation or degradation of the sources, changing their morphophysiological characteristics and its presence or absence in water. The quality of Papagaios’ river water was evaluated by physical-chemistry analysis and by density of Benthic macroinvertebrates. Four colleting stations from a stretch of the river were analyzed and samples of sediment and water were collected. At 2nd and 3rd stations there are two cold storage rooms installed at the river’s margins, which treat their effluents in stabilizing lagoons. The 4th station receives the ousting directly from a textile after it has passed by a treatment. Results obtained by biological methods indicated the presence of polluting elements in water. The river’s longitudinal gradient showed a typical sucessorial process of macroinvertebrates from polluted environments, with a significant increase in the density of Oligochaeta and Chironidade, organisms that are tolerant to impacts in water. Considering the four stations that were analyzed, the unwished impacts are occurring in three last ones with more intensity.
Editorial Special Issue on “Energetic Complementarity”  [PDF]
Alexandre Beluco
Energy and Power Engineering (EPE) , 2017, DOI: 10.4236/epe.2017.99033
Abstract: This editorial presents the motivations that were the focus of the papers that make up this Special Issue on energetic complementarity. The articles deal with the application of the concept of energetic complementarity in time under certain conditions and with the proposition of new means to evaluate complementarity in time between more than two renewable energy resources. An article further proposes a method for establishing energetic complementarity in space, a concept that is important and necessary for management and planning of energy resources but does not yet have tools that allow it to be quantified and handled appropriately. In addition, two letters to the editor discuss issues that still need to be matured for a better understanding and application of the concept of energetic complementarity, both in time and space.
Minamata Disease—Review  [PDF]
Alexandre Semionov
World Journal of Neuroscience (WJNS) , 2018, DOI: 10.4236/wjns.2018.82016
Abstract: Minamata disease is the name given to a neurological syndrome caused by or-ganic mercury intoxication. Most commonly it results from consumption of methylmercury contaminated seafood and in severe cases is classically mani-fested by concentric constriction of the visual fields, ataxia and sensory dis-turbance in the distal extremities. The radiographic and neuropathological find-ings parallel the clinical picture and typically consist of lesions selectively in-volving the visual cortex, cerebellum and postecentral gyri.
On Approximating the Gradient of the Value Function  [PDF]
Alexandre Dmitriev
Theoretical Economics Letters (TEL) , 2019, DOI: 10.4236/tel.2019.91011

The optimality conditions for macroeconomic problems with limited commitment often contain partial derivatives of the optimal value function, corresponding to the outside option. This paper contributes to the literature on recursive contracts by proposing an algorithm for approximating the gradient of the value function using simulation-based methods. Our method combines numerical solution and simulation of the model, Monte-Carlo integration and numerical differentiation. It does not suffer from the curse of dimensionality and is therefore convenient for models involving many state variables. The algorithm inherits the speed and accuracy limitations of the numerical solution method it relies on. Our accuracy analysis is limited to a few classical examples from macroeconomic literature.

A Magnetically Levitated Precise Pointing Mechanism for Application to Optical Communication Terminals  [PDF]
Thomas Edward Donaldson Frame, Alexandre Alexandre Pechev
Optics and Photonics Journal (OPJ) , 2012, DOI: 10.4236/opj.2012.22012
Abstract: Increasing data bandwidth requirements from spacecraft systems is beginning to pressure existing microwave communications systems. Free-Space optical communications allows for larger bandwidths for lower relative power consumption, smaller size and weight when compared to the microwave equivalent. However optical communication does have a formidable challenge that needs to be overcome before the advantages of the technology can be fully utilized. In order for the communication to be successful the transmitter and receiver terminals need to be pointed with a high accuracy (generally in the order of ≤10 μradians) for the duration of communication. In this paper we present a new concept for the precise pointing of optical communications terminals (termed the Precise Pointing Mechanism). In this new concept we combine the separate pointing mechanisms of a conventional optical terminal into a single mechanism, reducing the complexity and cost of the optical bench. This is achieved by electromagnetically actuating the whole telescope assembly in 6 degrees-of-freedom with an angular resolution of less than ±3 μradians within a 10 (Az. El.) field of view and linear resolution of ±2 μm. This paper presents the new pointing mechanism and discusses the modelling, simulation and experimental work undertaken using the bespoke engineering model developed.
Bounds for Goal Achieving Probabilities of Mean-Variance Strategies with a No Bankruptcy Constraint  [PDF]
Alexandre Scott, Francois Watier
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.312A278

We establish, through solving semi-infinite programming problems, bounds on the probability of safely reaching a desired level of wealth on a finite horizon, when an investor starts with an optimal mean-variance financial investment strategy under a non-negative wealth restriction.

Vehicle to Grid Decentralized Dispatch Control Using Consensus Algorithm with Constraints  [PDF]
Alexandre Lucas, Sun Chang
Smart Grid and Renewable Energy (SGRE) , 2013, DOI: 10.4236/sgre.2013.46A002

With the transition to electric vehicle technologies, large scale support infrastructure is being deployed. The vehicleto-grid (V2G) concept is an opportunity to take advantage from both infrastructure and electric vehicle drive. However, coordinating large number of agents in a reasonable speed and lack of homogenous distribution of the service provided by vehicle users to the grid have been left unattended. We apply consensus theory to the V2G concept presenting a decentralized control solution to assure that all vehicles within a region, regardless of their technology, positioning or state of charge, can communicate with their neighbors and agree on how much energy each should individually exchange with the grid. Applying constraints to the system, we considered a 25,000 vehicle fleet connected to a grid during peak hours. Simulating power changes and vehicles entering and leaving the system, two groups of 5 vehicles were studied: the first group remained in the system during all peak hours, while the second group only an hour. Results showed that the two groups of vehicles despite connecting to the system at different times were able to reach consensus in t = 15 s, and reported a maximum error of ε < 0.01% if left in the system during all peak hours.

Hubble’s Constant and Flat Rotation Curves of Stars: Are Dark Matter and Energy Needed?  [PDF]
Alexandre Chaloum Elbeze
Journal of Modern Physics (JMP) , 2017, DOI: 10.4236/jmp.2017.81003
Abstract: Although dark energy and dark matter have not yet been detected, they are believed to comprise the majority of the universe. Observations of the flat rotation curve of galaxies may be explained by dark matter and dark energy. This article, using Newton’s laws and Einstein’s theory of gravitation, shows that it is possible to define a new term, called E0, variable in time and space, of which one of its limits is the Hubble constant H0. I show that E0?is strongly linked to an explanation of the flat rotation curve of galaxies. This strong correlation between Hubble’s constant H0?and E0 enables us to solve the mystery of the surplus of gravity that is stabilizing the universe.
Page 1 /10515
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.