An analysis of household farm investment decisions under varying land tenure arrangements in Ghana

Land tenure insecurity is widely perceived as a disincentive for long-term land improvement investment hence the objective of this paper is to evaluate how tenure (in)security associated with different land use arrangements in Ghana influenced households’ plot level investment decisions and choices. The paper uses data from the Farmer-Based Organisations (FBO) survey. The FBO survey collected information from 2,928 households across three ecological zones of Ghana using multistaged cluster sampling. Probit and Tobit models tested the effects of land tenancy and ownership arrangements on households’ investment behaviour while controlling other factors. It was found that marginal farm size was inversely related to tenure insecurity while tenure insecurity correlate positively with value of farm land and not farm size. Individual ownership and documentation of land significantly reduced the probability of households losing uncultivated lands. Individual land ownership increased both the probability of investing and level of investments made in land improvement and irrigation probably due to increasing importance households place on land ownership. Two possible explanations for this finding are: First, that land markets and land relations have changed significantly over the last two decades with increasing money transaction and fixed agreements propelled by population growth and increasing value of land. Secondly, inclusion of irrigation investment as a long term investment in land raises the value of household investment and the time period required to reap the returns on the investments. Households take land ownership and duration of tenancy into consideration if the resource implications of land investments are relatively huge and the time dimension for harvesting returns to investments is relatively long.

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Estudio socioeconómico sobre desarrollo y fomento del empleo juvenil en la Comarca Oriental.

Conocer la realidad socioeconómica, los recursos, problemas y potencialidades de la Comarca, para así elaborar una estrategia de desarrollo y un Plan de Formación para el desarrollo de la Comarca. Según las encuestas: 286 jóvenes parados entre los 16 y 30 años de edad; 496 estudiantes de FP y BUP; 41 empresas de 5 a 50 empleados y a 13 de las registradas. El estudio presenta tres fases: A/ Análisis socioeconómico e inventario de recursos de la Comarca. B/ Definición de las directrices de una estrategia de desarrollo y de un plan formativo. C/ Evaluación de la propuesta de iniciativas locales de empleo. Cada una de las partes tuvo su propia organización aunque se procuró su conexión dentro de un planteamiento metodológico integral y globalizante con intención de servir para la planificación regional. Encuestas sobre equipamiento de los núcleos de población de Asturias, a las explotaciones ganaderas y a jóvenes parados, estudiantes, empresas y asociaciones. Se pone de manifiesto el alto grado de ruralización del empleo en comparación con el conjunto de la región. El empleo se centra en agricultura y pesca, aunque en los últimos años se ha producido un fenómeno de terciarización de la actividad económica que supuso la potenciación de empleo en el sector servicios y construcción. Son relativamente frecuentes los parados que buscan el primer empleo. Muy pocas empresas creen necesario realizar reducciones de plantilla y la mayoría piensan contratar nuevos trabajadores, sobre todo cualificados. Las empresas no disponen de medios adecuados para formar a sus trabajadores y aunque estos presentan unos niveles de formación aceptables, se demandan cualificaciones de caracter específico que no abundan en la zona. Escasean oficiales de albañilería, profesionales de hostelería. El futuro de la Comarca no es oscuro aunque tampoco se va a producir una recuperación inmediata. La revolución del empleo en la Comarca está muy vinculada a la marcha económica del país, aunque se podría acelerar garantizando el abastecimiento de mano de obra cualificada con cursos de formación en las actividades más demandadas (construcción, servicios) y suavizando trabas institucionales que se oponen al desarrollo de sectores como el del turismo, que parece ser la principal fuente de riqueza de la comarca. Los autores consideran que los objetivos fijados se cubrieron y que queda demostrada la utilidad de puntos de transferencia para lograr la convergencia de diferente personal, Instituciones y Organismos y afrontar la necesaria tarea de autoanálisis regional.

CoDa-dendrogram: A new exploratory too

The use of orthonormal coordinates in the simplex and, particularly, balance coordinates, has suggested the use of a dendrogram for the exploratory analysis of compositional data. The dendrogram is based on a sequential binary partition of a compositional vector into groups of parts. At each step of a partition, one group of parts is divided into two new groups, and a balancing axis in the simplex between both groups is defined. The set of balancing axes constitutes an orthonormal basis, and the projections of the sample on them are orthogonal coordinates. They can be represented in a dendrogram-like graph showing: (a) the way of grouping parts of the compositional vector; (b) the explanatory role of each subcomposition generated in the partition process; (c) the decomposition of the total variance into balance components associated with each binary partition; (d) a box-plot of each balance. This representation is useful to help the interpretation of balance coordinates; to identify which are the most explanatory coordinates; and to describe the whole sample in a single diagram independently of the number of parts of the sample

A Factor analysis of hidrochemical composition of Llobregat river basin

Hydrogeological research usually includes some statistical studies devised to elucidate mean background state, characterise relationships among different hydrochemical parameters, and show the influence of human activities. These goals are achieved either by means of a statistical approach or by mixing models between end-members. Compositional data analysis has proved to be effective with the first approach, but there is no commonly accepted solution to the end-member problem in a compositional framework. We present here a possible solution based on factor analysis of compositions illustrated with a case study. We find two factors on the compositional bi-plot fitting two non-centered orthogonal axes to the most representative variables. Each one of these axes defines a subcomposition, grouping those variables that lay nearest to it. With each subcomposition a log-contrast is computed and rewritten as an equilibrium equation. These two factors can be interpreted as the isometric log-ratio coordinates (ilr) of three hidden components, that can be plotted in a ternary diagram. These hidden components might be interpreted as end-members. We have analysed 14 molarities in 31 sampling stations all along the Llobregat River and its tributaries, with a monthly measure during two years. We have obtained a bi-plot with a 57% of explained total variance, from which we have extracted two factors: factor G, reflecting geological background enhanced by potash mining; and factor A, essentially controlled by urban and/or farming wastewater. Graphical representation of these two factors allows us to identify three extreme samples, corresponding to pristine waters, potash mining influence and urban sewage influence. To confirm this, we have available analysis of diffused and widespread point sources identified in the area: springs, potash mining lixiviates, sewage, and fertilisers. Each one of these sources shows a clear link with one of the extreme samples, except fertilisers due to the heterogeneity of their composition. This approach is a useful tool to distinguish end-members, and characterise them, an issue generally difficult to solve. It is worth note that the end-member composition cannot be fully estimated but only characterised through log-ratio relationships among components. Moreover, the influence of each endmember in a given sample must be evaluated in relative terms of the other samples. These limitations are intrinsic to the relative nature of compositional data

Compositional hypotheses of subcompositional stability and specific perturbation change and their testing

In standard multivariate statistical analysis common hypotheses of interest concern changes in mean vectors and subvectors. In compositional data analysis it is now well established that compositional change is most readily described in terms of the simplicial operation of perturbation and that subcompositions replace the marginal concept of subvectors. To motivate the statistical developments of this paper we present two challenging compositional problems from food production processes. Against this background the relevance of perturbations and subcompositions can be clearly seen. Moreover we can identify a number of hypotheses of interest involving the specification of particular perturbations or differences between perturbations and also hypotheses of subcompositional stability. We identify the two problems as being the counterpart of the analysis of paired comparison or split plot experiments and of separate sample comparative experiments in the jargon of standard multivariate analysis. We then develop appropriate estimation and testing procedures for a complete lattice of relevant compositional hypotheses

Compositional Time Series: An Application

The composition of the labour force is an important economic factor for a country. Often the changes in proportions of different groups are of interest. I this paper we study a monthly compositional time series from the Swedish Labour Force Survey from 1994 to 2005. Three models are studied: the ILR-transformed series, the ILR-transformation of the compositional differenced series of order 1, and the ILRtransformation of the compositional differenced series of order 12. For each of the three models a VAR-model is fitted based on the data 1994-2003. We predict the time series 15 steps ahead and calculate 95 % prediction regions. The predictions of the three models are compared with actual values using MAD and MSE and the prediction regions are compared graphically in a ternary time series plot. We conclude that the first, and simplest, model possesses the best predictive power of the three models

Multi-isotopic and compositional exploration of factors controlling nitrate pollution

In Catalonia, according to the nitrate directive (91/676/EU), nine areas have been declared as vulnerable to nitrate pollution from agricultural sources (Decret 283/1998 and Decret 479/2004). Five of these areas have been studied coupling hydro chemical data with a multi-isotopic approach (Vitòria et al. 2005, Otero et al. 2007, Puig et al. 2007), in an ongoing research project looking for an integrated application of classical hydrochemistry data, with a comprehensive isotopic characterisation (δ15N and δ18O of dissolved nitrate, δ34S and δ18O of dissolved sulphate, δ13C of dissolved inorganic carbon, and δD and δ18O of water). Within this general frame, the contribution presented explores compositional ways of: (i) distinguish agrochemicals and manure N pollution, (ii) quantify natural attenuation of nitrate (denitrification), and identify possible controlling factors. To achieve this two-fold goal, the following techniques have been used. Separate biplots of each suite of data show that each studied region has a distinct δ34S and pH signatures, but they are homogeneous with regard to NO3- related variables. Also, the geochemical variables were projected onto the compositional directions associated with the possible denitrification reactions in each region. The resulting balances can be plot together with some isotopes, to assess their likelihood of occurrence

El bienestar psicológico de los preadolescentes

Research on psychological well-being - as a component of quality of life - has paroduced notable developments during the last two decades. However, few instruments exist that are applicable to the study of psychological well-being among adolescents. This article presents the results of administering un instrument of this kind to a sample of 1590 Catalan adolescents between 12 and 14 years old. The instrument, Huebner's siss scale (Huebner, 1991a, 1994) had already been adapted to study a population of Spanish children (Alsinet, 1998). The results are compared to those of positive and negative affect scales administered to the same sample, and to those obtained by Huebner with a US sample. The results demonstrate good reliability, a consistent factor structure, a goodfunctioning of the scale in the Spanish population, and a pattern of answers consistent with the original results by Huebner

Puntuación de calcio coronario y presencia de estenosis significativas en arterias coronarias detectadas por angiografía multidetectores

Introducción: la presencia de calcio en las arterias coronarias ha sido previamente estudiada como predictor de eventos coronarios; sin embargo, su relación con la presencia de lesiones estenóticas significativas aún es incierta. Métodos: se revisaron los estudios de 207 pacientes asintomáticos en quienes se practico angiografía coronaria con tomografía multidetectores y puntaje de calcio coronario según el método de Agatston. Se evaluó la relación entre estos dos parámetros usando prueba de Chicuadrado y coeficiente de Pearson. Resultados: se encontró relación positiva y estadísticamente significativa entre la presencia de calcio evaluada por el método de Agatston y la presencia de lesiones estenóticas evaluadas por tomografía multidetector. Esta asociación fue independiente de la localización anatómica. Discusión: en pacientes asintomáticos, el puntaje de calcio y la presencia de lesiones estenóticas coronarias se encuentran relacionados. Esta relación puede ser relevante en el diseño o la implementación de métodos de tamizaje para enfermedad coronaria.

Introduction to Matlab - a self-study tutorial

Matlab is a high level language that is very easy to use and very powerful. It comes with a wealth of libraries and toolboxes, that you can use directly, so that you don't need to program low level functions. It enables you to display results very easily on graphs and images. To get started with it, you need to understand how to manipulate and represent data, and how to find information about the available functions. During this self-study tutorial, you will learn: 1- How to start Matlab. 2- How you can find out all the information you need. 3- How to create simple vectors and matrices. 4- What functions are available and how to find them. 5- How to plot graphs of functions. 6- How to write a script. After this (should take about an hour), you will know most of what you need to know about Matlab and should definitely know how to go on learning about it on your own…

Correlacion entre bilirrubinometría transcutanea y bilirrubina serica en neonatos a termino o cercanos al termino con ictericia

La ictericia es causa frecuente de hospitalización en neonatos. El objetivo principal fue establecer la correlación entre bilirrubinometría transcutánea y bilirrubina sérica, y su utilidad para identificar requerimiento de fototerapia. Materiales y métodos: Es un estudio descriptivo de correlación. Incluyó neonatos con realización de bilirrubinometría transcutánea y bilirrubina sérica. Se calculan índices de correlación de Pearson para el tórax y la frente. La variabilidad de las diferencias entre niveles transcutáneos y bilirrubina séricas, se correlacionan, mediante diagrama de Bland-Altman. Se obtienen mediciones de desempeño de la prueba, con sensibilidad y especificidad. Resultados: Se incluyeron 88 Neonatos, con 112 bilirrubinometrías transcutáneas, (mediana en tórax: 6,0 mg/dl y en frente: 5,9 mg/dl). Se tomaron 95 muestras de bilirrubina sérica, (mediana: 7,2 mg/dl). Los índices de correlación de Pearson fueron 0.83 (tórax) y 0.93 (frente). Utilizando puntos de corte establecidos, para determinar la necesidad de fototerapia, se obtuvieron, sensibilidad del 93 % y especificidad del 86 % (tórax), y sensibilidad del 94% y especificidad del 83 % (frente). Utilizando percentiles 75 del gráfico de Buthani, se obtuvieron sensibilidad del 83% y Especificidad del 98% para la bilirrubinometría transcutánea. Discusión: Las mediciones transcutáneas se correlacionaron bien con las sanguíneas. Las sensibilidades obtenidas fueron satisfactorias. Conclusión: Las mediciones transcutáneas, hubieran detectado la mayoría de infantes que requirieron fototerapia, confirmando la utilidad como método no invasivo en la práctica clínica.

Investigación en el Medio : una experiencia de aula.

Este material es fruto del al Memoria del Curso de Actualización Científica y Didáctica para el profesorado de Educación Infantil, organizado en el año 1992 por la Dirección General de Ordenación e Innovación Educativa. En él se expone una experiencia basada en la aproximación a la Naturaleza desde la escuela y en cómo proceder para que ésta, junto con la familia, ofrezca a los más pequeños prácticas que faciliten sus primeros aprendizajes.

Off the record: más que un derecho una necesidad

… Los medios buscan la verdad y la exponen, pero para llegar a ésta última instancia deben cumplic con una condición: tienen que reservarse la fuente. El publicar un testimonio o denuncia sin la referencia explícita a la fuente es un recursdo típico dentro de la teoría de la comunicación, se trata de las fuentes o declaraciones off the record.

Expediente sobre petición de rentas al Rey de España para el sustento económico del Colegio Mayor del Rosario

Expediente presentado por los rectores del Colegio Mayor de Nuestra Señora del Rosario al Rey de España, Patrono de Colegio, con el fin, de obtener una pensión de 500 ducados anuales para el pago de las cátedras. Incluye informes del Colegio del Rosario, dos cédulas reales expedidas por el rey Carlos II de España y la Reina Mariana de Austria y un auto emitido por el presidente del Nuevo Reino de Granada don Diego Córdoba Lasso de la Vega. Siendo rector el doctor don Cristóbal de Torres Bravo.