Technical instruments and conceptual definitions: theoretical and practical implications of the change on the definition of unemployment in Colombia

En junio de 2000 el Departamento Nacional de Estadística de Colombia adopto una nueva definición de medición de desempleo siguiendo los estándares sugeridos por la organización Internacional del Trabajo (OIT). El cambio de definición implico una reducción de la tasa de desempleo en cerca de dos puntos porcentuales. En este documento contrastamos la experiencia colombiana con otra experiencias internacionales, y analizamos las implicaciones empíricas y teóricas de este cambio de definición usando dos tipos de estimaciones cuantitativas: en la primera se contrasta las principales características de las diferentes categorías clasificadas según la definición nueva y vieja de desempleo (empleado, desempleado y fuera de la fuerza laboral) usando el algoritmo EM; en la segunda se pone a prueba la implicación del desempleo estructural y su relación con el perfil educacional de personas desempleadas y las características teóricas que enfrentan los estándares de la OIT en la definición de empleo.

Philip's history atlas : 2000 years of world and british history.

Veinte siglos de historia del mundo y de historia británica organizados cronológica y temáticamente en este Atlas de Historia. Contiene temas claves para estudiantes de secundaria desde el Imperio Romano y China Antigua hasta los conflictos del mundo y las operaciones pacificadoras en 1990.

Practical intelligence : the art and science of common sense.

El autor se basa en las inteligencias múltiples para explicar cómo la inteligencia práctica es una habilidad clave de la vida y ofrece una estructura conceptual para definir y describir el sentido común. Expone cómo las personas con inteligencia práctica pueden emplear los conocimientos lingüísticos para adoptar hábitos de lenguaje semánticamente buenos, tomar decisiones mejores, pensar en términos de opciones y posibilidades, aceptar la ambigüedad y la complejidad, articular problemas con claridad y trabajar a través de soluciones. Muestra que las habilidades de inteligencia práctica se pueden mejorar con la educación y el entrenamiento adecuado y desafía a todos para mejorar sus destrezas y ayudar a otros a desarrollar sus propias capacidades de inteligencia práctica.

Practical applications of quantum molecular similarity measures (QMSM): programs and examples

Es descriu l'aproximació de Capes Atòmiques dins de la teoria de la Semblança Molecular Quàntica. Partint només de dades teòriques, s'ha trobat una relació entre estructura molecular i activitat biològica per a diversos conjunts de molècules. Es descriuen els aspectes teòrics de la Semblança Molecular Quàntica i alguns exemples d'aplicació

Use of fibrolytic enzymes to improve the nutritive value of ruminant diets - A biochemical and in vitro rumen degradation assessment

Two commercial enzyme products, Depol 40 (D) and Liquicell 2500 (L), were characterised from a biochemical standpoint and their potential to improve rumen degradation of forages was evaluated in vitro. Enzyme activities were determined at pH 5.5 and 39 degreesC. Analysis of the enzyme activities indicated that L contained higher xylanase and endoglucanase, but lower exoglucanase, pectinase and alpha-amylase activities than D. The Reading Pressure Technique (RPT) was used to investigate the effect of enzyme addition on the in vitro gas production (GP) and organic matter degradation (OMD) of alfalfa (Medicago sativa L.) stems and leaves. A completely randomised design with factorial arrangement of treatments was used. Both alfalfa fractions were untreated or treated with each enzyme at four levels, 20 h before incubation with rumen fluid. Each level of enzyme provided similar amounts of filter paper (D1, L1), endoglucanase (D2, L2), alpha-L-arabinofuranosidase (D3, L3) and xylanase units (D4, L4) per gram forage DM. Enzymes increased the initial OMD in both fractions, with improvements of up to 15% in leaves (D4) and 8% in stems (L2) after 12 h incubation. All enzyme treatments increased the extent of degradation (96 h incubation) in the leaf fractions, but only L2 increased final OMD in the stems. Direct hydrolysis of forage fractions during the pre-treatment period did not fully account for the magnitude of the increases in OMD, suggesting that the increase in rate of degradation was achieved through a combined effect of direct enzyme hydrolysis and synergistic action between the exogenous (applied) and endogenous (rumen) enzymes. (C) 2003 Elsevier Science B.V. All rights reserved.

A practical comparison of group-sequential and adaptive designs

Sequential methods provide a formal framework by which clinical trial data can be monitored as they accumulate. The results from interim analyses can be used either to modify the design of the remainder of the trial or to stop the trial as soon as sufficient evidence of either the presence or absence of a treatment effect is available. The circumstances under which the trial will be stopped with a claim of superiority for the experimental treatment, must, however, be determined in advance so as to control the overall type I error rate. One approach to calculating the stopping rule is the group-sequential method. A relatively recent alternative to group-sequential approaches is the adaptive design method. This latter approach provides considerable flexibility in changes to the design of a clinical trial at an interim point. However, a criticism is that the method by which evidence from different parts of the trial is combined means that a final comparison of treatments is not based on a sufficient statistic for the treatment difference, suggesting that the method may lack power. The aim of this paper is to compare two adaptive design approaches with the group-sequential approach. We first compare the form of the stopping boundaries obtained using the different methods. We then focus on a comparison of the power of the different trials when they are designed so as to be as similar as possible. We conclude that all methods acceptably control type I error rate and power when the sample size is modified based on a variance estimate, provided no interim analysis is so small that the asymptotic properties of the test statistic no longer hold. In the latter case, the group-sequential approach is to be preferred. Provided that asymptotic assumptions hold, the adaptive design approaches control the type I error rate even if the sample size is adjusted on the basis of an estimate of the treatment effect, showing that the adaptive designs allow more modifications than the group-sequential method.

Review of R&D progress and practical application of the solar photovoltaic/thermal (PV/T) technologies

In this paper, the global market potential of solar thermal, photovoltaic (PV) and combined photovoltaic/thermal (PV/T) technologies in current time and near future was discussed. The concept of the PV/T and the theory behind the PV/T operation were briefly introduced, and standards for evaluating technical, economic and environmental performance of the PV/T systems were addressed. A comprehensive literature review into R&D works and practical application of the PV/T technology was illustrated and the review results were critically analysed in terms of PV/T type and research methodology used. The major features, current status, research focuses and existing difficulties/barriers related to the various types of PV/T were identified. The research methods, including theoretical analyses and computer simulation, experimental and combined experimental/theoretical investigation, demonstration and feasibility study, as well as economic and environmental analyses, applied into the PV/T technology were individually discussed, and the achievement and problems remaining in each research method category were described. Finally, opportunities for further work to carry on PV/T study were identified. The review research indicated that air/water-based PV/T systems are the commonly used technologies but their thermal removal effectiveness is lower. Refrigerant/heat-pipe-based PV/Ts, although still in research/laboratory stage, could achieve much higher solar conversion efficiencies over the air/water-based systems. However, these systems were found a few technical challenges in practice which require further resolutions. The review research suggested that further works could be undertaken to (1) develop new feasible, economic and energy efficient PV/T systems; (2) optimise the structural/geometrical configurations of the existing PV/T systems; (3) study long term dynamic performance of the PV/T systems; (4) demonstrate the PV/T systems in real buildings and conduct the feasibility study; and (5) carry on advanced economic and environmental analyses. This review research helps finding the questions remaining in PV/T technology, identify new research topics/directions to further improve the performance of the PV/T, remove the barriers in PV/T practical application, establish the standards/regulations related to PV/T design and installation, and promote its market penetration throughout the world.

Negotiating collective and individual agency : a qualitative study of young women's reproductive health in rural India

The societal changes in India and the available variety of reproductive health services call for evidence to inform health systems how to satisfy young women's reproductive health needs. Inspired by Foucault's power idiom and Bandura's agency framework, we explore young women's opportunities to practice reproductive agency in the context of collective social expectations. We carried out in-depth interviews with 19 young women in rural Rajasthan. Our findings highlight how changes in notions of agency across generations enable young women's reproductive intentions and desires, and call for effective means of reproductive control. However, the taboo around sex without the intention to reproduce made contraceptive use unfeasible. Instead, abortions were the preferred method for reproductive control. In conclusion, safe abortion is key, along with the need to address the taboo around sex to enable use of "modern" contraception. This approach could prevent unintended pregnancies and expand young women's agency.

Genetic aspects of productive and reproductive traits in a Murrah buffalo herd in São Paulo, Brazil

This study investigated genetic trends of some productive and reproductive traits in a herd of Murrah buffalo raised in São Paulo, Brazil. Variance components for milk production (Mr), length of lactation (LL), calving interval (CI) and age of first calving (AFC) were estimated by che restricted maximum likelihood method, using an animal model. Estimated heritability values were 0.38; 0.01; 0.10 and 0.20 for MP, LL, CI and AFC, respectively. Estimated repeatability values were 0.50, 0.13 and 0.20 for MP, LL and CI, respectively. Means of predicted breeding values for cows, dams and sires according to calving year and the genetic correlations were presented.