Níveis críticos de fósforo no solo e nas folhas para a implantação de Eucalyptus grandis Hill ex Maiden, em quatro tipos de solos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tipos de resistência a Alabama Argillacea (Huebner, 1818) (Lepidoptera: Noctuidae) envolvidos em genótipos de algodoeiro: II. Antibiose

Cotton genotypes resistance to Alabama argillacea (Huebner, 1818) due to antibiosis has been evaluated in laboratory trials (at 27 ± 2°C, 70 ± 10% relative humidity and 14 hours photoperiod). Six different genetic materials (T 1122-13-1, STO 285 N, JPM 157, T 953-13-4-2, CNPA 9211-21, and CNPA 9211-31) have been tested in a completely randomized experimental design, with ten replications, each one with ten larvae/genotype. Larvae have been supplied with leaves daily. The following variables have been scored: time length of several insect stages (from larvae to adult), average mass of larvae and pupae as well as average larval, pre-pupal and pupal mortality rates. All genotypes have revealed longer overall average time length of stage duration from larvae to adult, as compared to STO 285 N; however, CNPA 9211-31 and CNPA 9211-21 have shown the smallest average mass of pupae along with high frequencies of pre-pupae and larvae to adult mortalities. The results strongly suggest that antibiosis is one of the resistance mechanisms to A. argillacea in that two cotton genotypes.

Variaciones del índice de cono en suelo movilizado posterior al tráfico de un tractor equipado con dos tipos de neumáticos y a cuatro velocidades de desplazamiento

The tractor is one of the machines that more traffics over the soil during the processes involving agricultural production. The interaction tractor/soil is made by the tires which, in most of the cases, are pneumatic. The tire type and the tractor travel speed, interfere directly on the pressure over the soil. One of the techniques employed to evaluate the alterations that tractor traffic causes in the soil is to measure its Cone Index. The aim of this research was to evaluate the same Cone Index alterations caused by an agricultural tractor equipped with both radial tires and bias ply tires, trafficking mobilized soil in four different travel speeds. The experiment was performed in a LATOSSOLO VERMELHO, located 22°51' S, 48°25'W and 770 m of altitude, in Botucatu-SP, Brazil. The soil mobilization was performed with a chisel plow and a disc arrow. The traction was accomplished with a John Deere tractor, model 6600, with 88 kW of power and 6,723 kg. Equipment requiring a force of 25kN was traced by the tractor draw bar. The experimental design was in randomized blocks with 4 × 2 factorial arrangements, with two distinct treatments corresponding to the types of tires (bias and radial) and the four travel speeds, with six replications. There were selected the following speeds: 3.5, 3.9, 5.1 and 5.9 km h-1. To determine the soil resistance, there was utilized MSSU - Mobile Soil Sampling Unit, with which the Cone Index was obtained in layers from 0-100, 100-200, 200-300, 300-400, 400-500 and over 500 mm deep. The Cone Index where evaluated in areas with non contact between tire and soil (ICn) and in the tire footprint track (ICp). There were calculated the Cone Index increments caused by the tractor tire (AIC) and the results showed that as the tractor travel speed increased, there were observed decrements in the medium values of cone index. The radial tire provided smaller values of the Cone Index in the superficial layer of the soil (0 to 100 mm) in relation to the bias ply tire, when the speed was approximately 6 km h-1. The increment in the Cone Index, promoted by the tractor, was more intense in the first 200 mm depth, but it also reached the layer from 200 to 300 mm.

Morfologia e morfometria dos tipos de fibras do músculo reto abdominal de cadelas (canis familiaris) durante a gestação

The present paper deals with the evaluation of morphological and morphometric alterations of slow-twist (I) and fast-twitch (II) fibers of rectus abdominis muscle of adult female dog during pregestational phase, at 30 and 60 days of pregnancy and at 30 days after the parturition. At the every phases, using the open biopsy technique, muscle samples were collected. The samples were plunged. Histological sections were cut in a microtome. For general morphology, some sections were stained with HE. Subsequent sections were reacted for myofibrillar ATPase (m-ATPase), after alkaline (pH 10.4) and acid (pH 4.4) pre-incubations, in order to identificate type I and II fibers. In the pre-gestational phase, muscle tissue revealed to be composed by fibers with different diameters, presenting polygonal outlines and one or more periphery nuclei. At 30 days of pregnancy, muscle fiber characteristics were similar. At 60 days, in addition to the existence of normal fibers, polymorphic and small diameter fibers were frequent. At 30 days after the parturation, the morphology of muscle fiber were similar to that observed in the pre-gestational phase. In the four phases, type II fiber diameters were lager than type I. The diameters of both fiber types showed a significant reduction in the 30 days phase and a significative increasing at 60 days. The expansion of the abdominal wall during the pregnancy represents a chronic stimulus, induced changes in the morphology and in the fiber type diameters.

Balance Preliminar de las Economías de América Latina y el Caribe 2010

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Estudio Económico de América Latina y el Caribe 2010-2011: modalidades de inserción externa y desafíos de política macroeconómica en una economía mundial turbulenta

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El comercio exterior de productos agropecuarios latinoamericanos = Special study on trade in agricultural commodities in Latin America

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Reformas estructurales, productividad y conducta tecnológica en América Latina

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Articulación productiva en el subsector vitivinícola chileno: el caso de la Asociación de Productores de Vinos Finos de Exportación (CHILEVID A.G.)

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Servicios a pequeños productores agrícolas: financiamiento y crédito

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Temas sobre el desarrollo de tecnologías para pequeños productores campesinos

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Apertura económica y (des)encadenamientos productivos

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Interacción entre productores rurales y ambiente natural: apuntes para una tipología

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Capital social y pequeños productores de leche en México: los casos de Alto Jalisco y Aguascalientes

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El mercado de la tierra en el Brasil y los pequeños productores

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