El acceso al agua de los agricultores familiares de la región pampeana : Un análisis multidimensional

Este artículo presenta, en su primera parte, el enfoque conceptual y metodológico de un proyecto de investigación-acción participativa abordado de forma interdisciplinaria. La investigación refiere a las diferentes dimensiones que condicionan el acceso al agua de los agricultores familiares en distintos sitios de la región pampeana. La problemática se define en la dinámica con los actores involucrados, considerando que el agua mediatiza las relaciones sociales -de apropiación para el riego y la producción agrícola y de otros sectores, el consumo y la eliminación de residuos- entre diferentes actores. En las últimas secciones se presentan algunas de las observaciones y reflexiones del equipo de investigación en base a los primeros avances del trabajo de campo

Introducción : Tecnologías digitales en la enseñanza, inclusión y complejidades de un fenómeno multidimensional

Fil: Asprella, Gabriel. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

El análisis multidimensional en el enfoque relacional de la desigualdad social

En esta ponencia presentaremos un caso de análisis multidimensional, que constituye parte del momento objetivista de una investigación acerca de la producción y la reproducción de la pobreza en la localidad de Malvinas Argentinas, provincia de Córdoba. Desde un enfoque relacional, se toma como eje la noción de estrategias de reproducción social y, más específicamente el lugar que ocupan en esa problemática los diferentes tipos de redes sociales que enlazan a las familias pobres entre sí y con otros agentes e instituciones que ocupan otras posiciones en el espacio social. Como parte de la reconstrucción de las relaciones objetivas que hacen posible la existencia de tales redes y establecen los límites y posibilidades de las prácticas e interacciones, expondremos la construcción del espacio social a partir de un análisis multidimensional que toma como base de información algunas de las variables captadas por el Censo de Población y Vivienda de 2001, desagregadas a nivel de segmentos censales. De este modo, la caracterización de la localidad implica asumir un principio de diferenciación fundamentado en la desigual distribución de recursos, en tanto propiedades pertinentes que fueron captadas por el censo, y a partir del cual proponemos una reconstrucción de clases basada en el volumen y la estructura de estas propiedades

Por una geografía de las territorialidades y las temporalidades : Una concepción multidimensional orientada a la cooperación y el desarrollo territorial

Una de las confusiones más presentes en el ámbito de la ciencia geográfica se refiere a la diferenciación de los conceptos de espacio y territorio; otra, también muy presente, es la que se refiere a la noción de territorialidad. Son cuestiones que se intentan esclarecer en el transcurso de este texto, recorriendo obras relativamente recientes ya consideradas clásicas en el pensamiento geográfico, y otras tal vez menos expresivas a nivel nacional, pero también muy importantes para la constitución de las perspectivas actuales de abordaje del territorio y la territorialidad. Se estudia la territorialidad humana, teniendo en cuenta simultáneamente nuestra sociabilidad, animalidad y espiritualidad, destacando la primera dimensión sin dejar de considerar las otras. El texto se refiere, por lo tanto, a las territorialidades del animal-hombre-social-espiritual, y no a los demás animales. Otra observación inicial importante se refiere a los niveles escalares y temporales con los cuales se trabaja. Cuando el texto se refiere a las escalas espaciales de análisis, se conciben de manera trans-multiescalar, o sea, a nivel local (calle, barrio, "comunidad" rural, etc.); a nivel municipal, estatal, regional, nacional, internacional y global; y al mencionar las escalas temporales, se entienden como tiempos instantáneos, períodos, fases, y como ritmos lentos y rápidos sincrónicos, en una perspectiva transtemporal histórica y coexistente. Uno de los objetivos es destacar la necesidad de comprensión de los ritmos y las desigualdades, en especial los más lentos, normalmente dejados de lado en los estudios de geografía (humana).

Global ASCII grids with daylenth values during summer and winter solstice and ASCII grids representing habitat suitability of Fucus distichus and its niche overlap with temperate macroalgae under present-day and future (2100, 2200) conditions

Abstract has to be submitted by the author!

Niche differentiation among mat-forming, sulfide-oxidizing bacteria in chemosynthetic ecosystems of the Nile Deep Sea Fan (Eastern Mediterranean Sea)

Sulfidic muds of cold seeps on the Nile Deep Sea Fan are populated by different types of mat-forming sulfide-oxidizing bacteria. The predominant sulfide oxidizers of three different mats were identified by microscopic and phylogenetic analyses as (i) Arcobacter species producing cotton-ball-like sulfur precipitates, (ii) large filamentous sulfur bacteria including Beggiatoa species, or (iii) single, spherical cells resembling Thiomargarita species. High resolution in situ microprofiles revealed different geochemical settings selecting for different mat types. Arcobacter mats occurred where oxygen and sulfide overlapped at the bottom water interface. Filamentous sulfide oxidizers were associated with non-overlapping, steep gradients of oxygen and sulfide. A dense population of Thiomargarita was favored by temporarily changing supplies of oxygen and sulfide. These results indicate that the decisive factors in selecting for different mat-forming bacteria within one deep-sea province are spatial or temporal variations in energy supply. Furthermore, the occurrence of Arcobacter spp.-related 16S rRNA genes in the sediments below all three types of mats, as well as on top of brine lakes of the Nile Deep Sea Fan, indicates that this group of sulfide oxidizers can switch between different life modes depending on the geobiochemical habitat setting.

Using ecological niche models to support tree species selection for forest restoration planning in largely deforested regions

Species selection for forest restoration is often supported by expert knowledge on local distribution patterns of native tree species. This approach is not applicable to largely deforested regions unless enough data on pre-human tree species distribution is available. In such regions, ecological niche models may provide essential information to support species selection in the framework of forest restoration planning. In this study we used ecological niche models to predict habitat suitability for native tree species in "Tierra de Campos" region, an almost totally deforested area of the Duero Basin (Spain). Previously available models provide habitat suitability predictions for dominant native tree species, but including non-dominant tree species in the forest restoration planning may be desirable to promote biodiversity, specially in largely deforested areas were near seed sources are not expected. We used the Forest Map of Spain as species occurrence data source to maximize the number of modeled tree species. Penalized logistic regression was used to train models using climate and lithological predictors. Using model predictions a set of tools were developed to support species selection in forest restoration planning. Model predictions were used to build ordered lists of suitable species for each cell of the study area. The suitable species lists were summarized drawing maps that showed the two most suitable species for each cell. Additionally, potential distribution maps of the suitable species for the study area were drawn. For a scenario with two dominant species, the models predicted a mixed forest (Quercus ilex and a coniferous tree species) for almost one half of the study area. According to the models, 22 non-dominant native tree species are suitable for the study area, with up to six suitable species per cell. The model predictions pointed to Crataegus monogyna, Juniperus communis, J.oxycedrus and J.phoenicea as the most suitable non-dominant native tree species in the study area. Our results encourage further use of ecological niche models for forest restoration planning in largely deforested regions.

On the Mahalanobis Distance Classification Criterion for Multidimensional Normal Distributions

Many existing engineering works model the statistical characteristics of the entities under study as normal distributions. These models are eventually used for decision making, requiring in practice the definition of the classification region corresponding to the desired confidence level. Surprisingly enough, however, a great amount of computer vision works using multidimensional normal models leave unspecified or fail to establish correct confidence regions due to misconceptions on the features of Gaussian functions or to wrong analogies with the unidimensional case. The resulting regions incur in deviations that can be unacceptable in high-dimensional models. Here we provide a comprehensive derivation of the optimal confidence regions for multivariate normal distributions of arbitrary dimensionality. To this end, firstly we derive the condition for region optimality of general continuous multidimensional distributions, and then we apply it to the widespread case of the normal probability density function. The obtained results are used to analyze the confidence error incurred by previous works related to vision research, showing that deviations caused by wrong regions may turn into unacceptable as dimensionality increases. To support the theoretical analysis, a quantitative example in the context of moving object detection by means of background modeling is given.

Assessing agriculture-water relationships: a Pan-European multidimensional modelling approach.

This paper aims at developing a simulation framework to jointly assess agricultural and water issues. While the strong linkages between water, food, and the environment call for an integrated and multidisciplinary modelling approach, a complete and consistent modelling system to evaluate food-water relationships in Europe was missing so far. The spatial economic simulation model for agriculture CAPRI, which comprises a set of environmental indicators to assess food-environment interrelations within European regions, has been extended to account for food-water links. This modelling framework enables simulating the potential impact of climate change and water availability on agricultural production at the EU regional level, as well as looking at the sustainable use of water, the implementation of water policies or the integration of water issues in the Common Agricultural Policy

Connexin-43 in the osteogenic BM niche regulates its cellular composition and the bidirectional traffic of hematopoietic stem cells and progenitors

Connexin-43 (Cx43), a gap junction protein involved in control of cell proliferation, differentiation and migration, has been suggested to have a role in hematopoiesis. Cx43 is highly expressed in osteoblasts and osteogenic progenitors (OB/P). To elucidate the biologic function of Cx43 in the hematopoietic microenvironment (HM) and its influence in hematopoietic stem cell (HSC) activity, we studied the hematopoietic function in an in vivo model of constitutive deficiency of Cx43 in OB/P. The deficiency of Cx43 in OB/P cells does not impair the steady state hematopoiesis, but disrupts the directional trafficking of HSC/progenitors (Ps) between the bone marrow (BM) and peripheral blood (PB). OB/P Cx43 is a crucial positive regulator of transstromal migration and homing of both HSCs and progenitors in an irradiated microenvironment. However, OB/P Cx43 deficiency in nonmyeloablated animals does not result in a homing defect but induces increased endosteal lodging and decreased mobilization of HSC/Ps associated with proliferation and expansion of Cxcl12-secreting mesenchymal/osteolineage cells in the BM HM in vivo. Cx43 controls the cellular content of the BM osteogenic microenvironment and is required for homing of HSC/Ps in myeloablated animals