Concentrations of dissolved and particulate manganese in waters of the Southwest Pacific

Concentrations of dissolved and particulate manganese in relation with organic matter in waters of the Southwest Pacific are under consideration.

Jugar no debería ser irregular

La importancia de incorporar actividades lúdicas, no como actividad ocasional sino como parte de la dinámica de la clase en tanto herramienta válida en la enseñanza de lenguas extranjeras, potenciadora de la integración y de la cohesión grupal, resulta indiscutible cuando trabajamos con niños o adolescentes. Sin embargo, solemos ser más reacios al considerar su uso con adultos. Al desafío que significa para el docente escoger, recrear o crear juegos para grupos, niveles y objetivos específicos, suele sumarse el temor a que los alumnos consideren "no seria" la propuesta. El objetivo de esta presentación es aportar algunas reflexiones en este sentido, a partir de la definición de juego y la consideración de distintos tipos y aplicaciones concretas en el aula de ELE, según la franja etaria.

La criminalización de la pobreza en niños y adolescentes en conflicto con la ley penal : Continuidad y ruptura entre el Paradigma de la Situación Irregular y el Paradigma de la Protección Integral

Fil: Ibarbia, María Milagros. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Inmigración y trabajo irregular en la agricultura: trabajadores tamaulipecos en Estados Unidos y jornaleros magrebíes en Andalucía

Tanto en Estados Unidos como en España, la escasez de mano de obra local dispuesta a aceptar las condiciones sociolaborales imperantes en la agricultura, unida a la dificultad de inspeccionar y regular un sector donde la movilidad de trabajadores es constante, ha conducido a que la agricultura sea la actividad donde encuentran empleo más fácilmente los trabajadores migrantes indocumentados. En Estados Unidos la demanda de empleo en la agricultura ha venido siendo cubierta principalmente por trabajadores mexicanos; mientras, en España, los jornaleros procedentes de Marruecos constituyen el colectivo de inmigrantes con mayor presencia en el sector agrario. Este artículo, fundamentado en una metodología cualitativa, analiza, por una parte, la situación socio-laboral de los inmigrantes procedentes de Marruecos en la agricultura de Andalucía, región situada en el sur de España. Por otra parte, examina la situación de los jornaleros de Tamaulipas, región situada en el noreste de México, empleados de forma estacional en el sector agrario estadounidense

Collection of data on particulate and dissolved soil phosphorus in the Jena Experiment (Main Experiment, time series since 2002)

This data set contains two time series of measurements of dissolved phosphorus (organic, inorganic and total with a biweekly resolution) and dissolved inorganic phosphorus with a seasonal resolution. In addition, data on phosphorus from soil samples measured in 2007 and fractionated by different acid-extrations (Hedley fractions) are provided. All data measured at the main experiment plots of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained by bi-annual weeding and mowing. 1. Dissolved phosphorus in soil solution: Suction plates installed on the field site in 10, 20, 30 and 60 cm depth were used to sample soil pore water. Cumulatively extracted soil solution was collected every two weeks from October 2002 to May 2006. The biweekly samples from 2002, 2003 and 2004 were analyzed for dissolved organic phosphorus (DOP), dissolved inorganic phosphorus (PO4P) and dissolved total phosphorus (TDP) by Continuous Flow Analyzer (CFA SAN ++, SKALAR [Breda, The Netherlands]). 2. Seasonal values of dissolved inorganic phosphorus in soil solution were calculated as volume-weighted mean values of the biweekly measurements (spring = March to May, summer = June to August, fall = September to November, winter = December to February). 3. Phosphorus fractions in soil: Five independent soil samples per plot were taken in a depth of 0-15 cm using a soil corer with an inner diameter of 1 cm. The five samples per plot were combined to one composite sample per plot. A four-step sequential P fractionation (Hedley fractions) was applied and concentrations of P fractions in soil were measured photometrically (molybdenum blue-reactive P) with a Continuous Flow Analyzer (Bran&Luebbe, Germany).

(Table 1) Characteristics of air temperature, sea surface temperature, sea surface salinity, nutrients, and total particulate matter for Admiralty Bay and Potter Cove, King George Island, Antarctica

Since the early 1990s, phytoplankton has been studied and monitored in Potter Cove (PC) and Admiralty Bay (AB), King George/25 de Mayo Island (KGI), South Shetlands. Phytoplankton biomass is typically low compared to other Antarctic shelf environments, with average spring - summer values below 1 mg chlorophyll a (Chl a)/m**3. The physical conditions in the area (reduced irradiance induced by particles originated from the land, intense winds) limit the coastal productivity at KGI, as a result of shallow Sverdrup's critical depths (Zc) and large turbulent mixing depths (Zt). In January 2010 a large phytoplankton bloom with a maximum of around 20 mg Chl a/m**3, and monthly averages of 4 (PC) and 6 (AB) mg Chl a/m**3, was observed in the area, making it by far the largest recorded bloom over the last 20 yr. Dominant phytoplankton species were the typical bloom-forming diatoms that are usually found in the western Antarctic Peninsula area. Anomalously cold air temperature and dominant winds from the eastern sector seem to explain adequate light : mixing environment. Local physical conditions were analyzed by means of the relationship between Zc and Zt, and conditions were found adequate for allowing phytoplankton development. However, a multiyear analysis indicates that these conditions may be necessary but not sufficient to guarantee phytoplankton accumulation. The relation between maximum Chl a values and air temperature suggests that bottom-up control would render such large blooms even less frequent in KGI under the warmer climate expected in the area during the second half of the present century.