The detection and correction of errors in agricultural surveys

Apresenta-se neste trabalho um procedimento prático e sua fundamentação estatística para detectar e corrigir erros que ocorrem durante o preenchimento de questionários em levantamentos de dados estatísticos. Embora tais erros ocorram em pequena proporção, seu efeito frequentemente é desproporcional à sua frequência. Sugere-se um modelo de correção, que é um caso de modelo de superpopulação associado ao estimador razão.A practical procedure and the corresponding statistical aspects are presented in order to detect respondent errors. Although it occurs in a small proportion of answered questions, its effect is often disproportionate to its frequency. A model for correction is suggested which is shown to be a case of superpopulation model associated to the ratio estimator

Modelling rural labor: an application to São Paulo, Brazil

The question of modelling rural labor is discussed and a seemingly unrelated regressions (SUR) model is suggested. An application is presented analyzing three labor categories in the State of São Paulo, Brazil; farmer' s family workers, permanent workers and temporary workers. A significant Breusch-Pagan test indicates the need of SUR

Relações dinâmicas entre preços da soja brasileira

Dynamic and causal relationships among soybean prices were studied using the Box-Jenkins approach and spectral analysis at three market levels: international price (Rotterdam), wholesale price (São Paulo City) and farmer's price (State of São Paulo, Brazil). The authors concluded that international price leads farmer's price and that there is feedback between farmer's price and wholesale price. Farmer's price leads at high frequencies (short-run influences) and is led at low frequencies (long-run influences).Utilizando-se modelos auto-regressivos integrados de médias móveis (ARIMA) e análise espectral, estudaram-se relações dinâmicas e relações causais entre preços de soja em três níveis de comercialização: internacional (bolsa de Rotterdam), atacadista (cidade de São Paulo) e de produtor (Estado de São Paulo). Encontraram-se relações causais do nível internacional para o nível de produtor e interdependência entre os preços nos níveis de atacado e de produtor. As influências sobre o preço do produtor ocorrem em baixas frequências, enquanto as influências em sentido inverso ocorrem em altas frequências

Improving oral presentation skills for radiology residents through clinical session meetings in the virtual world Second Life

Background: The objective of this study was to conduct a clinical session meeting in the virtual world of Second Life to improve the oral presentation skills of radiology residents and to assess the perception of the attendees. Methods: A clinical session meeting (10 two-hour sessions over four weeks), where participants presented their own clinical sessions, followed by a turn of interventions by the attendees, was designed and carried out. Attendees were asked to complete an evaluation questionnaire. Descriptive statistics were performed. Results: Twenty-eight radiology residents attended the meeting, and 23 (81.2%) completed the evaluation questionnaire; 95.7–100% of them agreed that the virtual environment was attractive and suitable for holding the meeting and that the content was appropriate for their training as residents. They rated with ≥8.9 points (from 1 to 10) different aspects of the experience, highlighting the role of teachers (9.7 ± 0.6) and the usefulness of their training (9.4 ± 0.9). Conclusions: Second Life can be used effectively to train oral communication skills in public, in an environment perceived as attractive and suitable for learning, through an experience described by the attendees as interesting and useful, highlighting the advantages of social contact with their peersWe want to acknowledge the Asociación de Radiólogos del Sur, a subsidiary of SERAM, for its contribution to the maintenance costs of the Medical Master Island during the development of this project. Partial funding for open access charge: Universidad de Málag

Causal analysis procedure focused on small software development organizations

Very Small Entities (VSE) dedicated to software development lack of enough resources to adopt causal analysis practices, defined in models as CMMI, due to their complexity and costs. It is important to detect the generated defects in the development process, and to make a systematic analysis aimed at determining its causes. However, identifying those root causes is an arduous task, and failing to do so leads to wrong decisions that either fail to solve the problem or even make it worse. On this basis, this paper proposes a causal analysis procedure focused on small organizations PAC-DS (according to its initials in Spanish), which includes activities aimed at identifying the defects causes. After its evaluation in a preliminary case study, the utility of the procedure was evidenced

Estudio experimental y modelización matemática de una unidad de suelo frío con ventilación incorporada

En los últimos años se ha empezado a utilizar sistemas de suelo frío para combatir parte de la carga sensible de los locales. Como la temperatura superficial del suelo está limitada por el riesgo de condensación, un sistema de suelo frío suele ir complementado con un sistema de ventilación que combate el resto de carga sensible que el suelo no es capaz de combatir, además de la carga de ventilación y la carga latente del local. Para unificar las unidades terminales, se propone en este estudio una integración del suelo frío con el sistema de ventilación [1]. El sistema consiste en una estructura modular que se dispone en el forjado y forma conductos de ventilación por donde circula el aire. Sobre esta estructura se coloca la red de tuberías, que quedan embebidas en la capa de mortero y sobre la que se dispone el acabado superficial del suelo. Las bocas de difusión se sitúan en el suelo, pudiendo ser ventilación por mezcla o desplazamiento. El trabajo que se presenta es un análisis numérico de la transferencia de calor en la unidad terminal de suelo frío con ventilación, mediante elementos finitos, realizado con el software COMSOL Multiphysics [2]. Además, se realiza un ensayo experimental. Se integra el sistema en un suelo de 3x3 m2 y se realiza un ensayo típico en condiciones de verano. Se describe el montaje del experimento, la monitorización llevada a cabo de los parámetros más importantes del sistema y el ensayo experimental. Se muestran los resultados experimentales, que confirman la estratificación de temperatura del aire de la zona. Por otro lado, la temperatura superficial media del suelo y la capacidad de refrigeración del sistema son dos de las variables utilizadas para comparar el ensayo experimental con la simulación numérica. El objetivo principal es validar el modelo numérico con los ensayos experimentales. El trabajo se encuadra en el proyecto UNICLIMA, financiado por AZVI en el marco de un proyecto de la Corporación Tecnológica de Andalucía y el CDTI

Utilización de la metodología de aula invertida en una asignatura de Fundamentos de Informática

En este trabajo presentamos la experiencia llevada a cabo durante el primer año de desarrollo de un proyecto de innovación docente financiado por la Universidad de Granada, en el que se ha aplicado la metodología de aula invertida utilizando los recursos propios de un MOOC (Massive Open Online Course), tales como videoclases, cuestionarios de auto-evaluación y foros de debate. Tras describir brevemente la plataforma tecnológica y la metodología docente, mostramos los principales resultados obtenidos de la encuesta de opinión realizada por los estudiantes y la mejora alcanzada en las calificaciones académicas con respecto a cursos anteriores. Finalmente, exponemos algunas conclusiones con la finalidad de seguir mejorando, no sólo los resultados académicos sino también el grado de satisfacción de estudiantes y profesores al utilizar este método.In this paper, we present the experience carried out during the first year of a teaching innovation project supported by the University of Granada. The aim of the project is to apply the Flipped Classroom methodology taking advantage of the learning resources included in a MOOC (Massive Open Online Course), such as video-lectures, self-assessment tests and discussion forums,. After a brief description of both the technological platform and the learning methodology, we show the main results obtained from a survey of students and the academic outcomes. Finally, we draw several conclusions in order to continue improving not only the academic results, but also the satisfaction degree of students and teachers with the application of the method.Universidad de Granada: Departamento de Arquitectura y Tecnología de Computadores; Vicerrectorado para la Garantía de la Calidad

MaTGeC: hacia un marco de trabajo para la gestión cuantitativa de procesos de desarrollo de software en pequeñas organizaciones

The small software development companies have difficulties in adopting practices about quantita­tive process management offered by reference models such as CMMI-DEV or ISO/IEC 15504 because it generates expensive investments in long-term periods of time. However, if they do not incorporate at least the essential practices, they won't be able to obtain processes with less variability in its performance and that can be sta­tistically under control which directly impacts the projects results because they would allow making better estimates. In this article, it is presented a general proposal of a framework for quantitative process management in very small entities (MaT-GeC) that offers a guide to monitor and assess specific processes selected by the organization. Moreover, it is indicated the components that con­form it, along with the practices, activities, roles and essential work products for that this kind of organizations to incorporate the quantitative man­agement fundamentals in their more critical tasks.Las organizaciones pequeñas desarrolladoras de software tienen dificultades para adoptar las prác­ticas sobre gestión cuantitativa de procesos ofre­cidas por modelos de referencia como CMMI-DEV o ISO/IEC 15504, debido a que les generan costosas inversiones a largo plazo. Sin embargo, en caso de que no incorporen al menos las prác­ticas esenciales, no podrán obtener procesos con menor variabilidad en su rendimiento y que pue­dan estar bajo control estadístico, lo que afecta de manera directa en el resultado de sus proyectos, ya que permitiría efectuar mejores estimaciones. En este artículo se presenta una propuesta gene­ral de un marco de trabajo para gestión cuanti­tativa de procesos para pequeñas organizaciones (MaTGeC) que ofrece una guía para monitorear y evaluar procesos específicos seleccionados por la organización. Posteriormente, se indican los com­ponentes que lo conforman, junto con las prácti­cas, actividades, roles y productos esenciales para que esta clase de organizaciones incorporen los fundamentos de gestión cuantitativa en sus tareas más críticas

Dimensionamento de amostra para levantamento da citricultura paulista

A sample is designed for a periodic citrus production survey in the State of São Paulo, Brazil. Three alternative designs (simple random sample, stratified sample by region and farm size, stratified sample by region, farm size and group within region) and nine levels of desired variance (10%, 5%, 2.5%, 1%, 0.5%, 0.4%, 0.3%, 0.2% and 0.1%) are compared. A stratified sample by region, size and group at level 1% with 583 elements is suggested.Dimensiona-se uma amostra para levantamento periódico da produção de citros no Estado de São Paulo. Três esquemas amostrais alternativos são comparados: 1) amostra casual simples (ACS); 2) amostra estratificada por regiões e tamanho do imóvel rural; e 3) amostra estratificada por regiões, tamanho do imóvel e grupo de municípios dentro da região. Nove níveis de variância desejada (10%, 5%, 2,5%, 1%, 0,5%, 0,4%, 0,3%, 0,2% e 0,1%) são comparados. Sugere-se o uso de uma amostra estratificada por região, tamanho e grupo, ao nível de 1%, com 583 elementos