967 resultados para arid and semiarid region
Resumo:
En este artículo se ponen en relación los resultados del estudio sobre los incentivos materiales del accionar cooperativo con las tendencias de la economía agraria y familiar, en Córdoba, desde la década de 1940 a 1960.Los nuevos mecanismos de comercialización colectiva, en donde participaba la entidad de segundo grado FACA (Federación Argentina de Cooperativas Argentinas) y a la cual estaban asociadas las cooperativas primarias adheridas a la Federación Agraria Argentina y, el Estado - a través del Instituto Argentino de Promoción al Intercambio- aumentaban el poder de negociación de los productores rurales. Por otro lado, las políticas crediticias provinciales fueron -ya desde el inicio del período considerado- favorables al sector agrario y cooperativo. Ambos factores -planteamos- actuaron como incentivos materiales al fortalecimiento de la economía familiar. Para analizar la economía agraria de los productores familiares trabajamos con datos censales a nivel micro-regional (departamento Tercero Arriba) y contextualizamos este estudio con resultados de otras investigaciones sobre las regiones pampeanas cordobesa y nacional. Trabajamos también las prácticas cooperativas con memorias, balances y actas de las entidades de la micro-región y, realizamos una primera aproximación a las políticas crediticias provinciales a las cooperativas, a través de fuentes producidas y existentes en el Banco Provincia de Córdoba.
Resumo:
In order to assess recent submarine volcanic contributions to the sediments from the active Kolbeinsey Ridge, surface samples were analyzed chemically. The contribution of major and trace elements studied differ within the study area. A statistical analysis of the geochemical variables using factor analysis and cluster method allows to distinguish possible sample groups. Cluster method identifies three distinct sediment groups located in different areas of sedimentation. Group 1 is characterized by highest contents of Fe2O3, V, Co, Ni, Cu and Zn demonstrating the input of volcaniclastic material. Group 2 comprises high values of CaCO3, CaO and Sr representing biogenic carbonate. Group 3 is characterized by the elements K, Rb, Cs, La and Pb indicating the terrigenous component. The absolute percentage of the volcanic, biogenic and terrigenous components in the bulk sediments was calculated by using a normative sediment method. The highest volcanic component (> 60% on a carbonate free basis) is found on the ridge crest. The biogenic component is highest (10-30%) in the eastern part of the Spar Fracture Zone influenced by the East Iceland Current. Samples from the western and southeastern region of the study area contain more than 90% of terrigenous component which appears to be mainly controlled by input of ice-rafted debris.
Resumo:
Radiolarians from two sites north of Little Bahama Bank (Sites 627 and 628) are correlated with assemblages from sites on the southeastern U.S. coastal plain and continental shelf and from DSDP Sites 391 and 534 in the Blake-Bahama Basin. Results show that deposition of biogenic silica-rich sediments occurred in this region from the late Oligocene through middle Miocene, although the record is interrupted by unconformities. Radiolarians help constrain the age of a mass-transported deposit at Site 627 that appears to be coeval with the Great Abaco Member of the Blake Ridge Formation.
Resumo:
El presente artículo se inscribe en una serie de trabajos focalizados en experiencias migratorias y construcción de identidades y alteridades étnico-nacionales que venimos realizando tanto en el área periurbana de producción hortícola como en el casco urbano de la ciudad de La Plata. (1) En ellos abordamos aspectos de la inserción local de los migrantes -en especial con respecto al caso boliviano- desde distintos ejes analíticos como son la adscripción étnico-nacional, el trabajo, el género, la participación institucional, la construcción de categorías de alteridad con respecto a los migrantes por parte de sujetos, instituciones y medios de comunicación locales, el uso de medios como estrategia de identificación / afirmación / participación desde los propios migrantes. En el caso específico de la migración boliviana a Argentina, tanto al área plenamente urbana como a la rural periurbana -en donde adquiere especial importancia-, constituye un fenómeno estructurado y con características propias, situación reforzada por el subempleo en las áreas de economía campesina en Bolivia y la demanda de algunos sectores de la economía argentina, como actualmente el de la construcción urbana y el de la producción hortiflorícola periurbana. En tal sentido el tema se constituye en referente privilegiado para destacar los aspectos dinámicos de la ciudad y su región. En este contexto expondremos algunas reflexiones conceptuales y resultados de trabajo de campo referidos a la auto y hetero demarcación de la pertenencia étnico-nacional como espacio identificatorio en las dimensiones de trabajo y género.
Resumo:
En este artículo se ponen en relación los resultados del estudio sobre los incentivos materiales del accionar cooperativo con las tendencias de la economía agraria y familiar, en Córdoba, desde la década de 1940 a 1960.Los nuevos mecanismos de comercialización colectiva, en donde participaba la entidad de segundo grado FACA (Federación Argentina de Cooperativas Argentinas) y a la cual estaban asociadas las cooperativas primarias adheridas a la Federación Agraria Argentina y, el Estado - a través del Instituto Argentino de Promoción al Intercambio- aumentaban el poder de negociación de los productores rurales. Por otro lado, las políticas crediticias provinciales fueron -ya desde el inicio del período considerado- favorables al sector agrario y cooperativo. Ambos factores -planteamos- actuaron como incentivos materiales al fortalecimiento de la economía familiar. Para analizar la economía agraria de los productores familiares trabajamos con datos censales a nivel micro-regional (departamento Tercero Arriba) y contextualizamos este estudio con resultados de otras investigaciones sobre las regiones pampeanas cordobesa y nacional. Trabajamos también las prácticas cooperativas con memorias, balances y actas de las entidades de la micro-región y, realizamos una primera aproximación a las políticas crediticias provinciales a las cooperativas, a través de fuentes producidas y existentes en el Banco Provincia de Córdoba.
Resumo:
The nine holes (556-564) drilled during DSDP Leg 82 in a region west and southwest of the Azores Platform (Fig. 1) exhibit a wide variety of chemical compositions that indicate a complex petrogenetic history involving crystal fractionation, magma mixing, complex melting, and mantle heterogeneity. The major element chemistry of each hole except Hole 557 is typical of mid-ocean ridge basalts (MORBs), whereas the trace element and rare earth element (REE) abundances and ratios are more variable, and show that both depleted Type I and enriched Type II basalts have been erupted in the region. Hole 556 (30-34 Ma), located near a flow line through the Azores Triple Junction, contains typically depleted basalts, whereas Hole 557 (18 Ma), located near the same flow line but closer to the Azores Platform, is a highly enriched FeTi basalt, indicating that the Azores hot-spot anomaly has existed in its present configuration for at least 18 Ma, but less than 30-34 Ma. Hole 558 (34-37 Ma), located near a flow line through the FAMOUS and Leg 37 sites, includes both Type I and II basalts. Although the differences in Zr/Nb and light REE/heavy REE ratios imply different mantle sources, the (La/Ce)ch (>1) and Nd isotopic ratios are almost the same, suggesting that the complex melting and pervasive, small-scale mantle heterogeneity may account for the variations in trace element and REE ratios observed in Hole 558 (and FAMOUS sites). Farther south, Hole 559 (34-37 Ma), contains enriched Type II basalts, whereas Hole 561 (14-17 Ma), located further east near the same flow line, contains Type I and II basalts. In this case, the (La/Ce)ch and Nd isotopic ratios are different, indicating two distinct mantle sources. Again, the existence along the same flow line of two holes exhibiting such different chemistry suggests that mantle heterogeneity may exist on a more pervasive and transient smaller scale. (Hole 560 was not sampled for this study because the single basalt clast recovered was used for shipboard analysis.) All of the remaining three holes (562, 563, 564), located along a flow line about 100 km south of the Hayes Fracture Zone (33°N), contain only depleted Type I basalts. The contrast in chemical compositions suggests that the Hayes Fracture Zone may act as a "domain" boundary between an area of fairly homogeneous, depleted Type I basalts to the south (Holes 562-564) and a region of complex, highly variable basalts to the north near the Azores hot-spot anomaly (Holes 556-561).
Resumo:
According to the drilling probes of the Deep Waier Drilling Project, Neogene sediments in a tropical area of the Pacific Ocean are divided into 15 zones based on diatoms. The author shows that a unique zonation may be applied for the entire region. Identification of diatoms zones boundaries was conducted through their direct correlation with nannoplancton, radiolarian and foraminiferal zonal sceals. Their ultra-structure and morphological relationship are being analysed. The mode of siliceous accumulation within the equatorial belt differed through the western central and eastern region since the early Miocene and the difference become more evident from the end of Middle Miocene. The distribution of Neogene diatomaceous silt in the tropical area is controlled by the character of gyre-water circulation and agrees with the modern geographical zonation.
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The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. Data sets in this collection provide methodological and environmental context to all samples collected during the Tara Oceans Expedition (2009-2013).
Resumo:
The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. The present data set provides environmental context to all samples from the Tara Oceans Expedition (2009-2013), including calculated averages of mesaurements made concurrently at the sampling location and depth, and calculated averages from climatologies (AMODIS, VGPM) and satellite products.
Resumo:
We estimated the relative contribution of atmospheric Nitrogen (N) input (wet and dry deposition and N fixation) to the epipelagic food web by measuring N isotopes of different functional groups of epipelagic zooplankton along 23°W (17°N-4°S) and 18°N (20-24°W) in the Eastern Tropical Atlantic. Results were related to water column observations of nutrient distribution and vertical diffusive flux as well as colony abundance of Trichodesmium obtained with an Underwater Vision Profiler (UVP5). The thickness and depth of the nitracline and phosphocline proved to be significant predictors of zooplankton stable N isotope values. Atmospheric N input was highest (61% of total N) in the strongly stratified and oligotrophic region between 3 and 7°N, which featured very high depth-integrated Trichodesmium abundance (up to 9.4×104 colonies m-2), strong thermohaline stratification and low zooplankton delta15N (~2 per mil). Relative atmospheric N input was lowest south of the equatorial upwelling between 3 and 5°S (27%). Values in the Guinea Dome region and north of Cape Verde ranged between 45 and 50%, respectively. The microstructure-derived estimate of the vertical diffusive N flux in the equatorial region was about one order of magnitude higher than in any other area (approximately 8 mmol m-2 d 1). At the same time, this region received considerable atmospheric N input (35% of total). In general, zooplankton delta15N and Trichodesmium abundance were closely correlated, indicating that N fixation is the major source of atmospheric N input. Although Trichodesmium is not the only N fixing organism, its abundance can be used with high confidence to estimate the relative atmospheric N input in the tropical Atlantic (r2 = 0.95). Estimates of absolute N fixation rates are two- to tenfold higher than incubation-derived rates reported for the same regions. Our approach integrates over large spatial and temporal scales and also quantifies fixed N released as dissolved inorganic and organic N. In a global analysis, it may thus help to close the gap in oceanic N budgets.