¿Por qué no están en la escuela? : modos de exclusión instrumental e incidentes críticos que empujaron a jóvenes de la provincia de Buenos Aires a dejar la escuela secundaria.

Monográfico con el título: 'Eficacia escolar y equidad'. Resumen basado en el de la publicación

Proyectos : una ventana abierta a nuevos aires

Una maestra narra su experiencia profesional basada en el trabajo por proyectos con alumnos de educación Infantil del CEIP Virgen de la Paz, de Puebla de Vicar (Almería). Expone cómo surge un proyecto, la necesidad de definir los espacios, tiempos y agrupaciones, al tiempo que se han de determinar los contenidos y objetivos adoptados al grupo y el sistema de evaluación.

Mirada de viajeros e historiografía: la campaña de Buenos Aires al concluir el s. XVIII (Estudios)

El artículo revisa los relatos de Francisco de Amigorena y de Alexander Gillespie, un funcionario y un militar, escritos a fines del siglo XVIII e inicios del XIX, que han sido la base de la historiografía tradicional argentina sobre el mundo rural de Buenos Aires. Desde la perspectiva de la nueva historiografía económica argentina y de la historia del paisaje, replantea la imagen de la conformación de las clases dominantes rurales de la época y el papel económico del interior de la pampa de la provincia de Buenos Aires. Específicamente, el artículo cuestiona la idea de un espacio desierto, tal como la pintó la historiografía romántica, y propone el perfil de un hinterland heterogéneo, dedicado a distintas actividades.

Narraciones compartidas: imaginarios políticos entre Charcas y Buenos Aires. (De las reformas borbónicas al proceso juntista) [Estudios]

Este artículo expone los vínculos entre las élites charqueñas y rioplatenses desde mediados del siglo XVIII hasta inicios del siglo XIX, con una mirada que incorpora la relación territorial y el vínculo de las culturas políticas que se entretejen en la conformación de ambas élites. El trabajo da cuenta de los vínculos políticos entre el mundo charqueño y el rioplatense, asumiendo ambas realidades como vinculadas e interdependientes, y muestra que dicho vínculo estuvo configurado por narraciones y preocupaciones comunes, el impacto de la crisis imperial de 1808, la resonancia de la insurgencia indígena en los años previos (La Gran Regelión de los Andes y la Rebelión de Túpac Katari) y las experiencias autonomistas del mundo andino: La Plata (Chiquisaca) y La Paz. Se utilizan los aportes de la historia conceptual y la sociología política para analizar esos complejos mundos políticos y de conformación de élites.

Declaración de Buenos Aires sobre la situación en Ecuador (Archivos)

Reunión Extraordinaria del Consejo de Jefas y Jefes de Estado y de Gobierno de la Unión de Naciones Suramericanas La Jefas y Jefes de Estado y de Gobierno de la UNASUR, reunidos en el Palacio San Martin, en Buenos Aires, República Argentina el 1ro de octubre de 2010.

Ambient solar wind's effect on ICME transit times

Most empirical and numerical models of Interplanetary Coronal Mass Ejection (ICME) propagation use the initial CME velocity as their primary, if not only, observational input. These models generally predict a wide spread of 1 AU transit times for ICMEs with the same initial velocity. We use a 3D coupled MHD model of the corona and heliosphere to determine the ambient solar wind's effect on the propagation of ICMEs from 30 solar radii to 1 AU. We quantitatively characterize this deceleration by the velocity of the upstream ambient solar wind. The effects of varying solar wind parameters on the ICME transit time are quantified and can explain the observed spread in transit times for ICMEs of the same initial velocity. We develop an adjustment formula that can be used in conjunction with other models to reduce the spread in predicted transit times of Earth-directed ICMEs.

Magnetic discontinuities in the near-earth solar wind: evidence of in-transit turbulence or remnants of coronal structure?

Fluctuations in the solar wind plasma and magnetic field are well described by the sum of two power law distributions. It has been postulated that these distributions are the result of two independent processes: turbulence, which contributes mainly to the smaller fluctuations, and crossing the boundaries of flux tubes of coronal origin, which dominates the larger variations. In this study we explore the correspondence between changes in the magnetic field with changes in other solar wind properties. Changes in density and temperature may result from either turbulence or coronal structures, whereas changes in composition, such as the alpha-to-proton ratio are unlikely to arise from in-transit effects. Observations spanning the entire ACE dataset are compared with a null hypothesis of no correlation between magnetic field discontinuities and changes in other solar wind parameters. Evidence for coronal structuring is weaker than for in-transit turbulence, with only ∼ 25% of large magnetic field discontinuities associated with a significant change in the alpha-to-proton ratio, compared to ∼ 40% for significant density and temperature changes. However, note that a lack of detectable alpha-to-proton signature is not sufficient to discount a structure as having a solar origin.

The regulations of Buenos Aires' private architecture during the Late Eighteenth Century

The article revises the new planning regulations introduced in Latin America under the Bourbon reform, looking at the real estate market that these new conditions created in the capital of the Viceroyalty of the River Plate.

Transit times – the link between hydrology and water quality at the catchment scale

In spite of trying to understand processes in the same spatial domain, the catchment hydrology and water quality scientific communities are relatively disconnected and so are their respective models. This is emphasized by an inadequate representation of transport processes, in both catchment-scale hydrological and water quality models. While many hydrological models at the catchment scale only account for pressure propagation and not for mass transfer, catchment scale water quality models are typically limited by overly simplistic representations of flow processes. With the objective of raising awareness for this issue and outlining potential ways forward we provide a non-technical overview of (1) the importance of hydrology-controlled transport through catchment systems as the link between hydrology and water quality; (2) the limitations of current generation catchment-scale hydrological and water quality models; (3) the concept of transit times as tools to quantify transport and (4) the benefits of transit time based formulations of solute transport for catchment-scale hydrological and water quality models. There is emerging evidence that an explicit formulation of transport processes, based on the concept of transit times has the potential to improve the understanding of the integrated system dynamics of catchments and to provide a stronger link between catchment-scale hydrological and water quality models.

Determinants of Accelerated Small Intestinal Transit in Alcohol-Related Chronic Pancreatitis

Patients with chronic pancreatitis may have abnormal gastrointestinal transit, but the factors underlying these abnormalities are poorly understood. Gastrointestinal transit was assessed, in 40 male outpatients with alcohol-related chronic pancreatitis and 18 controls, by scintigraphy after a liquid meal labeled with (99m)technetium-phytate. Blood and urinary glucose, fecal fat excretion, nutritional status, and cardiovascular autonomic function were determined in all patients. The influence of diabetes mellitus, malabsorption, malnutrition, and autonomic neuropathy on abnormal gastrointestinal transit was assessed by univariate analysis and Bayesian multiple regression analysis. Accelerated gastrointestinal transit was found in 11 patients who showed abnormally rapid arrival of the meal marker to the cecum. Univariate and Bayesian analysis showed that diabetes mellitus and autonomic neuropathy had significant influences on rapid transit, which was not associated with either malabsorption or malnutrition. In conclusion, rapid gastrointestinal transit in patients with alcohol-related chronic pancreatitis is related to diabetes mellitus and autonomic neuropathy.

Rock magnetism in soils of the Pampean plain. Buenos Aires province, Argentina. Linking climate and magnetic behaviour

Results of the study of Argiudolls in two localities (Zarate and Veronica) of the Pampean plain, Argentina, are presented in this contribution. This is a typical area covered by loess. The magnetic studies carried out allowed to determine the presence of detrital magnetite and titanomagnetite, as well as maghemite, pedogenic goethite and superparamagnetic particles (SP). In Veronica soils, a depletion of ferromagnetic minerals is recorded The dominant process in these soils has been the reductive loss of detrital magnetite and titanomagnetite. This is associated with a greater degree of evolution of the soil, which is determined by the concentration and type of detected clays. The higher clay concentration in these soils facilitated reducing conditions and a greater loss of detrital magnetic particles. The loss is reinforced under poor drainage conditions. In the poorly drained soil of Zarate, a concentration of magnetic particles is observed in the Bt horizon, which is associated with an illuviation process. The well drained soil of the same locality shows neoformation of SP particles. These particles would have an ephemeral life until a new wet period in the annual cycle occurs. Although some characteristics of the magnetic signal appear reinforced by the conditions of drainage, this aspect does not seem to be too significant, at least in the Pampean region with low topographic gradients.

A emergência de uma cidade mundial: os casos de São Paulo e Buenos Aires

Este projeto pretende verificar a funcionalidade das "Cidades Mundiais" dentro do contexto de uma economia globalizada. Adicionalmente, procura-se estudar se São Paulo e Buenos Aires tendem a ocupar o "posto" de "Cidade Mundial". Dada a evidência de integração comercial e considerando que esta integração se dá, em grande parte, com a Argentina, cabe verificar como se dará a integração entre as duas grandes metrópoles desses dois países em termos concorrenciais e de complementaridade.

O Flúor nas águas subterrâneas da Formação Santa Maria, na região de Santa Cruz do Sul e Venâncio Aires, RS, Brasil

Concentrações de fluoreto, até 11 mg L-1, têm sido detectadas no aqüífero da Formação Santa Maria, Sistema Aqüífero Guarani, na região central do Estado do Rio Grande do Sul, Brasil. As águas subterrâneas são utilizadas para abastecimento público e levaram a incidência de fluorose dental. Esta área é a maior produtora de tabaco no Brasil, com uma longa história de aplicação de fertilizantes. Duas hipóteses são investigadas na busca de elucidar a origem das anomalias de flúor, a primeira, se refere à contaminação desencadeada pelo uso de fertilizantes fosfatados nas plantações de tabaco, e a segunda relacionada à causa natural, geogênica, determinada por interações rocha-fluido no aqüífero confinado. A hipótese antropogênica é testada nos solos e águas do aqüífero freático. O monitoramento das concentrações de fluoreto em campo, durante o período de dois anos e os experimentos de laboratório de retenção e lixiviação de fluoreto em solos mostram que este elemento é retido pelos solos argilosos. Durante o período de monitoramento das águas do freático, concentrações maiores que 0,16 mg L-1 não foram registradas, confirmando que o fluoreto é sorvido pelos solos argilosos ou transportado para horizontes mais permeáveis para superfície ou água subterrânea, em processo lento. Análise estatística fatorial e de agrupamento associada a técnicas de modelamento geoquímico apontaram as afinidades químicas das águas subterrâneas e possíveis origens para o fluoreto. As águas subterrâneas da Formação Santa Maria são distinguidas em quatro grupos hidroquímicos, o primeiro, cloretado sódico, evolui para águas subterrâneas bicarbonatadas sódicas, e ambos grupos apresentam anomalias de fluoreto. O terceiro grupo é de águas bicarbonatadas cálcicas e o quarto tem o magnésio como parâmetro característico. As hipóteses lançadas são também discutidas com base em análises de isótopos estáveis da água, e de sulfato e nitrato dissolvidos nas águas subterrâneas, que indicam a precipitação meteórica como a principal fonte de recarga do aqüífero estudado. A composição isotópica do sulfato da água é similar a do sulfato nos fertilizantes, não sendo possível distingui-lo de outras fontes que também apresentam assinaturas isotópicas semelhantes. No entanto, os isótopos do nitrato dissolvido nas águas subterrâneas e dos fertilizantes sugerem que não existe uma relação direta com o uso de fertilizantes NPK. Os dados apresentados indicam que os elevados teores de fluoreto no aqüífero da Formação Santa Maria resultam de interações água-rocha associadas à circulação de fluídos em estruturas tectônicas regionais levando a mistura de águas subterrâneas de aqüíferos mais profundos.