Hacia la construcción de lecciones del posconflicto en América Latina y el Caribe: una mirada a la violencia juvenil en Centroamérica

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Violencia escolar y juvenil: un intento por comprender sus motivaciones

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Metodologias de pesquisa para o estudo geográfico da sociabilidade juvenil

This study aims to present the methodologies of research used to carry out the dissertation requirements related to the different times and spaces linked to the youth sociability. The methodologies are about qualitative features not at all unknown to the geography studies despite the little account taken on them. The methodologies are: eyewitness accounts, Oral History, interviews and groups of debate. With this purpose, this work intends to bring some contribution to geographers and beginners that have been looking for methodological references to their researches it also tries to facilitate the discussion on the methodological dimension in the geographical studies.

Classificação Estrutural e Qualidade da Madeira do Clone GT 1 de Hevea brasiliensis Muell. Arg

Latex is the main product extracted from rubber trees (Hevea brasiliensis). In Brazil, at the end of the production cycle of latex, the wood of rubber tree is traditionally used for energy purposes, but several international studies have reported consolidated practices of adding value to it. The objective of this paper was to evaluate the quality of wood and classify it structurally based on its mechanical properties. Six 20-year-old trees of the clone GT 1 of rubber tree proceeding from Itajobi, State of Sao Paulo, Brazil were sampled. Reduced dimensions specimens in the radial direction of the wood were produced to evaluate the quality by compression parallel to the grain, static bending and Janka hardness tests. Two specimens, one from the lower log (since the ground up to breast height) and one from the higher log (from breast height up to 2.50 m) were produced for structural classification of the wood based on the characteristic strength in compression parallel to the grain (NBR 7190 norm, 1997). The wood was classified as C40 (fc0k ≥ 40 MPa) class. Results revealed that the strength was not statistically different in the radial direction (except for the Janka hardness), though tending to increase from pith to bark.

America Central: estimaciones de la mortalidad infantil y juvenil. Aplicacion de la tecnica de Brass y las variantes de Sullivan y Trussell, 1970

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Delimitação entre os lenhos juvenil e adulto de pinus elliottii engelm

Trees produce different types of woody tissue during growth. The xylem produced in the first years until a certain cambial age is called juvenile wood and has different physical, mechanical, chemical and anatomical characteristics from that produced later, when the cambial cells have matured. Thus, prior knowledge of the quality of the wood is of fundamental importance for choosing the best use of the material. This work aimed at using data from length of the tracheid and wood density to define the age transition from juvenile to mature wood. For this, three Pinus elliottii var. elliottii trees, aged 35 years, were collected at the Itapetininga Experimental Station, located in the state of São Paulo, Brazil. From each tree, disks of about 5 cm thick were obtained 0.05 m above the ground and used to determine the radial density by the gamma ray attenuation method and to measure the length of the tracheids. The results obtained by linear regression analysis showed that juvenile wood is limited to the first seven years of tree growth and the formation of mature wood occurs after twenty years. For the mature wood, there are significant differences among the averages obtained from the tracheid length and wood density.

Painéis de partículas de madeira leucena e resina poliuretana derivada de óleo de mamona

This research aimed to test particleboard with leucena (Leucaena leucocephala) wood particles and polyurethane resin castor oil based. The response variables are: modulus of rupture (MOR), internal adhesion (AI), apparent density (dap) and wood moisture content (um). The experiments were developed based on the methodological procedures of the ABNT NBR 14810:2002 standard. The particleboards were manufactured by hot-pressing at 4MPa and 90°C, using timber particles with 5% of moisture content and 10% of monocomponent and bicomponent polyurethane resin. The higher moisture content was achieved when the monocomponent polyurethane resin was used. The bicomponent polyurethane resin provided a percent increase of 43.7% and 22.7% on the modulus of rupture and apparent density, respectively, when compared to the standard limit. The internal adhesion of the panels manufactured with monocomponent resin was 2.45 times higher than the standard limit. The confidence interval between means revealed that the internal adhesion and apparent density exhibited statistical equivalence. A good correlation between the internal adhesion and apparent density was found, for this reason it was possible to estimate the internal adhesion of the panels based on the apparent density data.

Los desafíos de fin de siglo y la problemática juvenil rural en América Latina

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Los desafíos de fin de siglo y la problemática juvenil rural en América Latina

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Brasil: la mortalidad infantil y juvenil y los niveles de fecundidad en las regiones Noreste y Sureste. Censo de 1970

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Honduras: diferenciales de mortalidad infantil y juvenil a partir de informacion censal

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Mortalidad infantil y juvenil para Costa Rica y Peru segun datos PECFAL Rural 1969

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Estimacion de los niveles de fecundidad y mortalidad infantil y juvenil del Brasil y del estado de Maranhao, a partir del censo de 1970

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Venezuela: analisis de la mortalidad infantil y juvenil

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