501 research outputs found

    Fogo bacteriano das pomáceas.

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    bitstream/item/40813/1/cir21.pd

    Normas técnicas e documentos de acompanhamento da produção Integrada de maçã- 2º versão.

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    bitstream/item/60750/1/CNPUV-DOC.33-04.pdf2. ed

    Methane production from mixed tropical savanna and forest vegetation in Venezuela

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    International audienceMeasurements of methane concentrations in the boundary layer in the northern part of the Guayana shield, Venezuela, during the wet season (October 1988), showed the presence of substantial methane surface emissions. The measuring site is within the savanna climate region, but is affected by emissions from savanna and forest vegetation. From day versus night concentration measurements, with higher concentrations during night, a methane source strength near the site of 3?7×1011 molecules/cm2/s can be estimated, which includes emissions from small tracts of flooded soils, termites and especially tropical vegetation. Extrapolated to the entire savanna, this may imply a methane source of ~30?60 Tg yr?1 similar to the one calculated for tropical vegetation on the basis of recently published in vitro plant emission experiments by Keppler et al. (2006), which indicate emissions of ~30 Tg yr?1 for tropical savannas and grasslands and ~78 Tg yr?1 for tropical forests

    Características e controle da podridão "olho de boi" nas maçãs do sul do Brasil.

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    bitstream/item/55164/1/cir066.pd

    Source gases: Concentrations, emissions, and trends

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    Source gases are defined as those gases that influence levels of stratospheric ozone (O3) by transporting species containing halogen, hydrogen, and nitrogen to the stratosphere. Examples are the CFC's, methane (CH4), and nitrous oxide (N2O). Other source gases that also come under consideration in an atmospheric O3 context are those that are involved in the O3 or hydroxyl (OH) radical chemistry of the troposphere. Examples are CH4, carbon monoxide (CO), and nonmethane hydrocarbons (NMHC's). Most of the source gases, along with carbon dioxide (CO2) and water vapor (H2O), are climatically significant and thus affect stratospheric O3 levels by their influence on stratospheric temperatures. Carbonyl sulphide (COS) could affect stratospheric O3 through maintenance of the stratospheric sulphate aerosol layer, which may be involved in heterogeneous chlorine-catalyzed O3 destruction. The previous reviews of trends and emissions of source gases, either from the context of their influence on atmospheric O3 or global climate change, are updated. The current global abundances and concentration trends of the trace gases are given in tabular format

    Distinct Chemical Regions in the "Prestellar" Infrared Dark Cloud G028.23–00.19

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    We have observed the Infrared Dark Cloud (IRDC) G028.23–00.19 at 3.3 mm using the Combined Array for Research in Millimeter-wave Astronomy. In its center, the IRDC hosts one of the most massive (~1520 M_☉) quiescent, cold (12 K) clumps known (MM1). The low temperature, high NH2D abundance, narrow molecular line widths, and absence of embedded infrared sources (from 3.6 to 70 μm) indicate that the clump is likely prestellar. Strong SiO emission with broad line widths (6-9 km s^(–1)) and high abundances ((0.8-4) × 10^(–9)) is detected in the northern and southern regions of the IRDC, unassociated with MM1. We suggest that SiO is released to the gas phase from the dust grains through shocks produced by outflows from undetected intermediate-mass stars or clusters of low-mass stars deeply embedded in the IRDC. A weaker SiO component with narrow line widths (~2 km s^(–1)) and low abundances (4.3 × 10^(–11)) is detected in the center-west region, consistent with either a "subcloud-subcloud" collision or an unresolved population of a few low-mass stars. We report widespread CH_3OH emission throughout the whole IRDC and the first detection of extended narrow methanol emission (~2 km s^(–1)) in a cold, massive prestellar clump (MM1). We suggest that the most likely mechanism releasing methanol into the gas phase in such a cold region is the exothermicity of grain-surface reactions. HN^(13)C reveals that the IRDC is actually composed of two distinct substructures ("subclouds") separated in velocity space by ~1.4 km s^(–1). The narrow SiO component arises where the subclouds overlap. The spatial distribution of C2H resembles that of NH_2D, which suggests that C_2H also traces cold gas in this IRDC

    La observación sistemática de vecindarios: el caso de Chile y sus perspectivas para trabajo social

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    El estudio acerca de las características de los vecindarios y sus efectos sobre las personas ha llegado a ser un área de creciente atención por parte de investigadores de diversas disciplinas en países desarrollados. Aunque actualmente existen diversas metodologías para estudiar efectos del vecindario, una de las más utilizadas es la Observación Sistemática de Vecindarios –Systematic Social Observation SSO, en inglés—porque permite recolectar información acerca de diversas características del entorno físico, social, ambiental y económico de los vecindarios donde se aplica. El objetivo de este artículo es (i) dar a conocer sumariamente algunas investigaciones influyentes sobre efectos del vecindario en Estados Unidos, ii) describir cómo se diseñó e implementó la Observación Sistemática de Vecindarios en la ciudad de Santiago de Chile, iii) señalar algunos facilitadores y obstaculizadores de la implementación del proyecto y, finalmente iv) enunciar posibles contribuciones y limitaciones que esta metodología ofrecería al trabajo social en Chile.The study of neighborhood characteristics and their effects on individuals has become an area of increasing attention by scholars from various disciplines in developed countries. Although there are various methods to study neighborhoods and their impact on human populations, one of the most used is the Systematic Social Observation –Observación Sistemática de Vecindarios (OSV), in Spanish—because it allows the collection of information about various features of the physical, social, environmental and economic characteristics of neighborhoods. The purpose of this article is to (i) briefly present some research on neighborhood effects influential in the U.S., ii) describe how they Systematic Social Observation was designed and implemented in the city of Santiago, Chile, iii) discuss some facilitators and obstacles of the implementation process and, finally iv) list possible contributions and limitations this approach would offer the profession of social work in Chile.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4004073/Accepted manuscrip

    The Radio Ammonia Mid-plane Survey (RAMPS) Pilot Survey

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    The Radio Ammonia Mid-Plane Survey (RAMPS) is a molecular line survey that aims to map a portion of the Galactic midplane in the first quadrant of the Galaxy (l = 10°–40°, | b| \leqslant 0\buildrel{\circ}\over{.} 4) using the Green Bank Telescope. We present results from the pilot survey, which has mapped approximately 6.5 square degrees in fields centered at l = 10°, 23°, 24°, 28°, 29°, 30°, 31°, 38°, 45°, and 47°. RAMPS observes the NH3 inversion transitions NH3(1,1)–(5,5), the H2O 61,6–52,3 maser line at 22.235 GHz, and several other molecular lines. We present a representative portion of the data from the pilot survey, including NH3(1,1) and NH3(2,2) integrated intensity maps, H2O maser positions, maps of NH3 velocity, NH3 line width, total NH3 column density, and NH3 rotational temperature. These data and the data cubes from which they were produced are publicly available on the RAMPS website (http://sites.bu.edu/ramps/)
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