202 research outputs found

    Modélisation des durées de résidence à partir des données transversales

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    La compréhension du comportement temporel de plusieurs phénomènes urbains est essentielle pour analyser et modéliser leur développement. Cet objectif se heurte à la rareté et coût des bases de données longitudinales. Nous proposons un modèle paramétrique simple pour estimer des durées à partir de données transversales, qui est appliqué à l'analyse de l'ancienneté résidentielle dans la région IdF, avec des données du recensement. Cet outil pourrait avoir d'autres applications plus générales, comme la calibration des modèles LUTI

    Estado de la convivencia escolar, conflictividad y su forma de abordarla en establecimientos educacionales de alta vulnerabilidad social de la provincia de Concepción, Chile

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    Las investigaciones realizadas en torno a la convivencia escolar han aportado valiosos resultados que entregan una variada información relativa a las dinámicas de interacción que se dan en un centro escolar en donde podemos encontrar variados matices que favorecen o dificultan el clima en los centros educativos. La presente investigación, se adentro en la realidad cotidiana de ocho establecimientos educacionales de dependencia administrativa municipal, caracterizadas por sus elevados índices de vulnerabilidad escolar, con el fin de poder describir el estado de la convivencia escolar, de la conflictividad y sus formas de abordarla, considerando la opinión del estudiantado, profesorado y de las familias. Los resultados obtenidos reflejan que los tres colectivos estudiados valoran positivamente la convivencia escolar de los respectivos centros estudiados, en donde se estima que las relaciones que se establecen entre el estudiantado, profesorado y familias son buenas. En relación a la aplicación de las normas de convivencias el estudiantado piensa que son administradas sin mayores diferencias por parte del profesorado, lo cual aporta a la creación de un clima que estimula la buena convivencia. En el profesorado y familias se encontró una mayor gama de respuestas que fluctúan entre el acuerdo y desacuerdo.Respecto de la participación familiar, se encontró una positiva opinión de su nivel de involucramiento en los tres colectivos. En cuanto a la conflictividad, se encontró que tanto el estudiantado como las familias piensan que existen pocos enfrentamientos en el profesorado y el alumnado, sin embargo el profesorado estima que si los hay. Respecto de la existencia de malas contestaciones en clases la mitad del estudiantado y las familias piensan que se dan, a diferencia del profesorado que señalan lo contrario.Del mismo modo, al ser consultado por el cumplimiento de las normas de convivencia, tanto el alumnado como las familias opinan que estas se abordan adecuadamente, al contrario de la opinión docente que señala que estás se cumplen deficitariamente. En relación a insultos entre el alumnado, tanto el profesorado como las familias señalan que estás se dan mucho, sin embargo en el estudiantado se encontró la opinión contraria. Respecto de la existencia de peleas entre el estudiantado, existen coincidencia en la opinión del profesorado y las familias, señalando que estas se dan, sin embargo el estudiantado opina que estas dan poco, o no se dan. Al ser consultados por grupos que no se llevan bien, nuevamente el profesorado y las familias coinciden en la existencia de grupos que no se llevan bien. Sin embargo en el alumnado prevalecen las respuestas que este comportamiento se da poco o no se da. En cuanto a la existencia de niños y niñas que no están integrados y se sienten solos, en el estudiantado prevalece una visión que tiende a opinar que esto no es así, sin embargo en el profesorado y las familias, las opiniones reflejan lo contrario, siendo las respuestas de los familiares las que más reflejan esta tendencia...Research work carried out related to school coexistence has provided valuable findings which supply varied information related to interaction dynamics happening at school centers where diverse aspects that could encourage or hinder school environment can be found. Present research analyzed everyday reality of eight educational centers belonging to the municipal managing system characterized by their high levels of school vulnerability with the purpose of describing school coexistence status, conflict occurrence and the ways to address it considering the opinion of students, teachers and respective families. Obtained results show that three studied groups value in a positive way school coexistence at the respective analyzed institutions, where relationships generated among students, teachers and family are good. As for the application of coexistence standards students believe they are applied with no significant differences by teachers; this fact assists to the generation of an environment which encourages proper school coexistence. Among teachers and families a larger range of answers which fluctuate between agreement and disagreement was found. As regards as family participation a positive opinion related to its level of involvement was found.As for conflict occurrence it was found that both students and families consider that there is little confrontation between teachers and students. However, teachers consider there are conflicts indeed. With regard to the existence of inappropriate replies in class half of students and families consider there are bad replies in contrast to teachers that report the opposite. Likewise, when students and families are questioned about proper standards of coexistence they both state they are being successfully addressed. Nevertheless, teachers consider that coexistence standards are poorly executed. As regards as insults among students both teachers and families report that this is a common situation at school. However, the opposite view was found among students. As for fighting among students there is a common view shared by teachers and families. They both report there are fight instances. However, students consider there is few fighting or there is none. When teachers and families are asked about groups that do not get along, they both agree with the existence of them. However, students report this particular behavior is unusual or absent. As for the existence of boys and girls that are not integrated and feel lonely, students tend to consider this is not the case. However, the opinion of teachers and families is the opposite one. Families´ answers are the ones that most show this particular trend. The question concerning if teachers care only about their own matters was answered in an homogeneous way by students and their families; this fact shows that some think this is true and others consider it is the opposite, unlike teachers, who mostly report this is not the case. When teachers and families were asked if students thought their teachers understood them it was found that teachers and families think they do, unlike students where the opposite opinion prevails..

    Large-sample hydrology: recent progress, guidelines for new datasets and grand challenges

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    Large-sample hydrology (LSH) relies on data from large sets (tens to thousands) of catchments to go beyond individual case studies and derive robust conclusions on hydrological processes and models. Numerous LSH datasets have recently been released, covering a wide range of regions and relying on increasingly diverse data sources to characterize catchment behaviour. These datasets offer novel opportunities, yet they are also limited by their lack of comparability, uncertainty estimates and characterization of human impacts. This article (i) underscores the key role of LSH datasets in hydrological studies, (ii) provides a review of currently available LSH datasets, (iii) highlights current limitations of LSH datasets and (iv) proposes guidelines and coordinated actions to overcome these limitations. These guidelines and actions aim to standardize and automatize the creation of LSH datasets worldwide, and to enhance the reproducibility and comparability of hydrological studies

    Función de biomasa para Acacia caven (Mol.) Mol. distribuida en áreas secas del centro sur de Chile

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    Acacia caven is a key native species in the dry land region of south-central Chile. It is a species of high social and productive interest to landowners. Therefore, this study proposes a biomass function for A. caven, which involves incorporating predictor variables that are easily obtainable in the field and less complex than those used in already existing functions for the species. Due to the multi-purpose nature of the species and its potential for silvopastoral systems, these functions typify important planning tools to improve the management of this plant resource. To generate the biomass function, the methodology of destructive analysis of components was used on a total of 71 trees. These trees were selected, cut and weighed in the field to generate and test different models. Statistical analysis models were used and root collar diameter, diameter at breast height and total height served as predictor variables, resulting in a good adjustment of the models (R2 adjusted the 0.97 for stem-branches, 0.90 for stems and 0.96 for total biomass), with high correlations between estimated and real values. These functions may be used safely in plant formations of A. caven located in the same distribution area and within the range of the used variables. In the future, however, they require validation with new measurements in other sectors than the area considered to increase geographical representativeness.Acacia caven, es una de las principales especies nativas presentes en el secano interior de la zona central de Chile. Es una especie que tiene un alto interés social y productivo para los propietarios de este recurso. En este sentido, el objetivo de este estudio es proponer una función de biomasa validada para A. caven, y que incorpore variables predictoras de fácil obtención en terreno y de menor complejidad que las consideradas en funciones ya conocidas para la especie. Dadas las características de especie multipropósito y su potencial para su uso en sistemas silvopastorales, estas funciones son importantes herramientas de planificación para mejorar la gestión y manejo de este recurso vegetacional. Para la generación de la función de biomasa, se utilizó una metodología de análisis destructivo por componentes de 71 árboles, los cuales fueron seleccionados, volteados y pesados en terreno, para posteriormente generar y probar diferentes modelos. A través de análisis estadísticos se seleccionaron modelos que utilizan como variables predictoras el diámetro a la altura del cuello, diámetro a la altura del pecho y altura total. Los resultados muestran un buen ajuste de los modelos (R2 ajust. de 0,97 para fuste-ramas, 0,90 para ramillas y 0,96 para biomasa total), lo que indica un alto nivel de correlación entre valores estimados y valores reales. Estas funciones se pueden utilizar con seguridad en formaciones vegetacionales de A. caven que se ubiquen en la misma zona distribucional del recurso y dentro de los rangos de las variables utilizadas, siendo conveniente en el futuro validarlas con nuevas mediciones de sectores distintos al área considerada para estos análisis, aumentando su representatividad geográfica.Fil: Lucero Ignamarca, Alejandro. Universidad de Concepción (Chile)Fil: Muñoz Sáez, Fernando. Universidad de Concepción (Chile)Fil: Cancino Cancino, Jorge. Universidad de Concepción (Chile)Fil: Sotomayor Garreton, Alvaro. Universidad de Concepción (Chile)Fil: Dube, Francis. Universidad de Concepción (Chile)Fil: Villarroel Muñoz, Arnoldo. Universidad de Concepción (Chile)Fil: Sáez Carrillo, Katia. Universidad de Concepción (Chile

    The CAMELS-CL dataset: catchment attributes and meteorology for large sample studies – Chile dataset

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    We introduce the first catchment dataset for large sample studies in Chile. This dataset includes 516 catchments; it covers particularly wide latitude (17.8 to 55.0∘ S) and elevation (0 to 6993 m a.s.l.) ranges, and it relies on multiple data sources (including ground data, remote-sensed products and reanalyses) to characterise the hydroclimatic conditions and landscape of a region where in situ measurements are scarce. For each catchment, the dataset provides boundaries, daily streamflow records and basin-averaged daily time series of precipitation (from one national and three global datasets), maximum, minimum and mean temperatures, potential evapotranspiration (PET; from two datasets), and snow water equivalent. We calculated hydro-climatological indices using these time series, and leveraged diverse data sources to extract topographic, geological and land cover features. Relying on publicly available reservoirs and water rights data for the country, we estimated the degree of anthropic intervention within the catchments. To facilitate the use of this dataset and promote common standards in large sample studies, we computed most catchment attributes introduced by Addor et al. (2017) in their Catchment Attributes and MEteorology for Large-sample Studies (CAMELS) dataset, and added several others. We used the dataset presented here (named CAMELS-CL) to characterise regional variations in hydroclimatic conditions over Chile and to explore how basin behaviour is influenced by catchment attributes and water extractions. Further, CAMELS-CL enabled us to analyse biases and uncertainties in basin-wide precipitation and PET. The characterisation of catchment water balances revealed large discrepancies between precipitation products in arid regions and a systematic precipitation underestimation in headwater mountain catchments (high elevations and steep slopes) over humid regions. We evaluated PET products based on ground data and found a fairly good performance of both products in humid regions (r>0.91) and lower correlation (r<0.76) in hyper-arid regions. Further, the satellite-based PET showed a consistent overestimation of observation-based PET. Finally, we explored local anomalies in catchment response by analysing the relationship between hydrological signatures and an attribute characterising the level of anthropic interventions. We showed that larger anthropic interventions are correlated with lower than normal annual flows, runoff ratios, elasticity of runoff with respect to precipitation, and flashiness of runoff, especially in arid catchments. CAMELS-CL provides unprecedented information on catchments in a region largely underrepresented in large sample studies. This effort is part of an international initiative to create multi-national large sample datasets freely available for the community. CAMELS-CL can be visualised from http://camels.cr2.cl and downloaded from https://doi.pangaea.de/10.1594/PANGAEA.894885
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