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Search Results: 1 - 10 of 23826 matches for " Fernando Falco; "
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Selección de hábitat: efecto de la cobertura y tipo de suelo en lombrices de tierra
FALCO, Liliana Beatriz;MOMO, Fernando;
Acta zoológica mexicana , 2010,
Abstract: a laboratory experiment was carried out in order to verify the effect of soil cover and quality on habitat selection behavior of two earthworm species: amynthas gracilis and aporrectodea caliginosa. the experiment used two environmental factors: organic matter content (om) of the soil, and presence or absence of dead oak leaves (quercus robur). amynthas gracilis selects its habitat depending on the presence of dead leaves, regardless of the soil om content; this behavior is coherent with the epi-endogeic habit of this earthworm. on the other hand, a. caliginosa selects its habitat depending on the om content of the soil, regardless of the presence of leaves. as a. caliginosa preferred the poorer soil (<4% om), it should be classified as a mesohumic endogeic species.
Liliana Beatriz Falco,Fernando Momo
Acta zoológica mexicana , 2010,
Abstract: En el presente estudio analizamos en laboratorio, el efecto de la cobertura y calidad de suelo sobre la conducta de selección de hábitat para dos especies de lombrices de tierra: Amynthas gracilis y Aporrectodea caliginosa. Se analizaron dos factores, el contenido de materia orgánica del suelo (MO) y la presencia o no de hojarasca de roble (Quercus robur). Amynthas gracilis selecciona el hábitat por la presencia de la hojarasca en superficie antes que por su contenido de MO. Esto corresponde con su carácter de epi-endogea, que se alimenta de MO en superficie. Por su parte A. caliginosa selecciona el hábitat por el tipo de suelo, antes que por la presencia de hojarasca en superficie. Aporrectodea caliginosa prefirió el suelo con menor contenido de MO (<4 %), mostrando que dentro de las endogeas debe ser clasificada como una especie mesohúmica.
La dinámica espaciotemporal de una población multiespecífica de lombrices en un rodal de roble
Momo, Fernando R.;Falco, Liliana B.;
Acta zoológica mexicana , 2010,
Abstract: we studied the spatial dynamics of endogeic earthworms in a quercus robur forest. samples were taken using a 30 point grid every three months during a year plus a summer. growth rates were estimated for each point based on abundance data. abundances appeared to be correlated in the direction nw-se showing a net movement of the organisms to the se region of the studied field. the migration speed of earthworms was 1.2 m month-1. we fitted the spatial dynamics to several growth mathematical models; the most accurate models were the logistic model of smith, that is a model with physiological constraints, and the non-symmetric logistic equation, that considers inter-specific competition. the models revealed a significant non-hierarchic diffuse competition and a low rate of individual resource consumption. moreover, growth rates were high at low population densities but remained roughly constant at densities above 20 individuals m-2.
Fernando R. Momo,Liliana B. Falco
Acta zoológica mexicana , 2010,
Abstract: Se estudió la dinámica de una población multiespecífica de lombrices endogeas en un rodal de robles (Quercus robur) tomando muestras en peque os parches sobre un mosaico. Se tomaron muestras con reposición en una grilla de 30 puntos equidistantes. La frecuencia de muestreo fue estacional (cada tres meses) durante cinco estaciones. A partir de los datos de abundancias se estimaron las tasas de crecimiento en cada punto y se correlacionaron con las abundancias en el mismo punto y en los puntos vecinos para detectar la dirección de máxima correlación que resultó ser NO-SE. La velocidad migratoria media de las lombrices en esa dirección fue de 1.2 m mes-1. Se pusieron a prueba cuatro modelos de dinámica de abundancias; dos de ellos, el modelo logístico de Smith (que incorpora los diferentes requerimientos energéticos según el tama o individual) y la logística asimétrica (que considera competencia intraespecífica con variación no lineal con la densidad) mostraron un ajuste significativo a los datos, revelando un predominio de competencia difusa no jerárquica, una baja tasa de consumo de recursos por individuo y una tasa de crecimiento muy alta a densidades peque as y casi constante a densidades por encima de los 20 individuos m-2.
Equity Valuation and Accounting Numbers: Applying Zhang (2000) and Zhang and Chen (2007) models to Brazilian Market
Fernando Caio Galdi,Rodrigo Falco Lopes
Revista Brasileira de Finan?as , 2011,
Abstract: This paper investigates how accounting variables explain cross-sectional stocks returns in Brazilian capital markets. The analysis is based on Zhang (2000) and Zhang and Chen (2007) models. These models predict that stock returns are a function of net income, change in profitability, invested capital, changes in opportunity growths and discount rate. Generally, the empirical results for the Brazilian capital market are consistent with the theoretical relations that models describe, similarly to the results found in the US. Using different empirical tests (pooled regressions, Fama-Macbeth and panel data) the results and coefficients remain similar, what support the robustness of our findings.
Desenvolvimento e análise de uma rede neural artificial para estimativa da erosividade da chuva para o Estado de S?o Paulo
Moreira, Michel Castro;Cecílio, Roberto Avelino;Pinto, Francisco de Assis de Carvalho;Pruski, Fernando Falco;
Revista Brasileira de Ciência do Solo , 2006, DOI: 10.1590/S0100-06832006000600016
Abstract: knowledge on rainfall erosivity (r) of particular sites is fundamental for soil loss estimation by the universal soil loss equation (usle) and therefore highly important in conservation planning. in order to obtain the r value estimates for places where it is unknown, an artificial neural network (ann) was developed for the state of s?o paulo, and its accuracy compared with the inverse distance weighted (idw) interpolation method. the developed ann presented a smaller mean relative error in the r estimation and a confidence index classified as "excellent", better than the idw. ann can therefore be used to estimate r values for soil use planning, management and conservation in s?o paulo state.
Aspergilosis: una patología a considerar
Oxilia,Héctor Guillermo; Oxilia,Rodrigo Guillermo; Morales,Lorena; Falco,Fernando;
Revista argentina de radiolog?-a , 2008,
Abstract: pulmonary aspergillosis is a mycotic infection caused by the aspergillus fumigatus, saprophyte of the normal human sputum. five patients with non invasive aspergillosis were studied, of whom 4 were adults (3 women, 1 man) and one, pediatric, with invasive aspergillosis. all of them were studied by conventional x-ray, spiral ct, multislice ct and video capsule endoscopy. the presentation is predominant among men (3 to 1). there are three forms of presentation: a) invasive: in neutropenic patients it prevails the lung affectation; the brain, heart, kidney gastrointestinal tract, liver, thyroid and spleen spreading has a bad prognosis and mortality rate is very high; b) semiinvasive: it mainly compromises patients with pre-existing pulmonary pathology; c) non invasive: affects pre-existing cavities, tbc caverns or cysts where the fungus establishes; it is called aspergilloma or mycetoma.
Momentos-L: teoria e aplica??o em hidrologia
Valverde, Ana Esmeria Lacerda;Leite, Helio Garcia;Silva, Demétrius David da;Pruski, Fernando Falco;
Revista árvore , 2004, DOI: 10.1590/S0100-67622004000600019
Abstract: this technical note aimed to review the l-moments methods which have been proposed to calculate the parameters of the main distributions of probabilities used in hydrological studies. it also aimed to infer on the type of statistical distribution most used for specific applications. based on the review, it was concluded that when analyzing data of extreme events it is advisable to test the adherence of, at least, the following distributions of three parameters: generalized logistics, generalized of extreme events, pearson type iii and generalized of pareto. it was also concluded that the parameters of these distributions and its quantis should be estimated using the l-moment derived of the moments weighted by probability.
Perdas de solo, nutrientes, matéria organica e efeitos microestruturais em Argissolo Vermelho-Amarelo sob chuva simulada
Schaefer Carlos Ernesto Reynaud,Silva Demétrius David,Paiva Karlos Welby Neri,Pruski Fernando Falco
Pesquisa Agropecuária Brasileira , 2002,
Abstract: Estudo experimental com simulador de chuva foi conduzido em área de Argissolo Vermelho-Amarelo caulinítico, em Vi osa, MG, com intensidade de precipita o de 60 mm h-1 e seis aplica es sucessivas, espa adas de 12 horas. Caracterizou-se a evolu o do selamento superficial e das perdas de nutrientes, solo e matéria organica em raz o de diferentes porcentagens de cobertura (0, 20, 40, 80 e 100%) em cultivo morro abaixo (declividade média de 9,5%), em resposta à energia cinética decorrente da precipita o. As perdas totais de solo foram superiores a 11 t ha-1 nos tratamentos com porcentagem de cobertura entre 0 e 40%, reduzindo-se a pouco mais de 5 t ha-1 com 80% até zero no tratamento 100% coberto com Bidim. As perdas de nutrientes seguiram a ordem Ca>Mg>K>P e foram correlacionadas às perdas de matéria organica. O fracionamento de substancias húmicas revelou a concentra o residual de humina e perdas seletivas de formas mais solúveis (ácidos fúlvicos) com a enxurrada. A eros o causou heterogeneidade entre a parte superior e inferior das parcelas experimentais. A macroporosidade entre 10 e 20 cm é maior na parte superior da parcela, sugerindo a migra o de argila dispersa e entupimento de macroporos nas condi es de chuva simulada. Excetuando-se o tratamento com 100% de cobertura, todos os demais evidenciam crosta deposicional. Nos tratamentos com maior exposi o houve presen a de crosta erosional, ao fim do teste de campo.
Avalia o de interpoladores para os parametros das equa es de chuvas intensas no Espírito Santo
Roberto Avelino Cecílio,Alexandre Candido Xavier,Fernando Falco Pruski,Maycon Patrício de Hollanda
Ambiente e água : An Interdisciplinary Journal of Applied Science , 2009,
Abstract: Intense rainfalls are often responsible for the occurrence of undesirable processes in agricultural and forest areas, such as surface runoff, soil erosion and flooding. The knowledge of intense rainfall spatial distribution is important to agricultural watershed management, soil conservation and to the design of hydraulic structures. The present paper evaluated methods of spatial interpolation of the intense rainfall parameters (“K”, “a”, “b” and “c”) for the Espírito Santo State, Brazil. Were compared real intense rainfall rates with those calculated by the interpolated intense rainfall parameters, considering different durations and return periods. Inverse distance to the 5th power IPD5 was the spatial interpolation method with better performance to spatial interpolated intense rainfall parameters.
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