Validación de un cuestionario para medir retrospectivamente la exposición laboral a plaguicidas

ResumenObjetivosValidar un cuestionario diseñado para medir retrospectivamente la exposición laboral a plaguicidas en un estudio de casos y controles sobre trabajadores expuestos a plaguicidas y malformaciones congénitas.MétodosSe compara la información obtenida mediante una entrevista personal con 56 agricultores con: 1) una entrevista con los empleadores de los agricultores, 2) la observación directa de los lugares de trabajo y 3) un cuestionario que cumplimentaron los agncultores durante la realización del Programa de Capacitación para Manipuladores de Plaguicidas.ResultadosLos índices de exactitud y fiabilidad fueron altos para las variables «cultivos trabajados», «períodos de tratamiento» y «utilización de protección personal», con sensibilidades entre 0,81 y 1 e índices Kappa de 0,65 a 0,80. Sin embargo, las variables «duración de los tratamientos» y «productos plaguicidas utilizados» presentaron índices de exactitud más bajos con sensibilidades entre 0,32 y 0,50.ConclusionesLos resultados sugieren que el cuestionario es un buen instrumento para la medición de algunas variables pero en otras reflejan la existencia de problemas de recuerdo. Esto hace necesario adoptar medidas que mejoren la exactitud de la medida de la exposición como la introducción en el cuestionario del tamaño del área tratada como otra variable que permita valorar la duración de la exposición y la utilización de listas de recuerdo de productos plaguicidas durante la entrevista.SummaryObjectiveThe aim of this study is to validate a questionnaire intended to assess retrospective occupational exposure to pesticides in a case control study of workers exposed to pesticides and congenital malformations.MethodsOccupational data were gathered through personal interviews to 56 agricultural workers and this information was compared to: 1) personal interviews with the workers’ foremen, 2) direct observation of working places and 3) another questionnaire self-administered previously by the workers as a part of the «Training Program for Pesticide Aplicators».ResultsAccuracy and reliability indices are high for variables such as the crops where the interviewees have been working, the time period of the treatments with pesticides and the use of personal protection during treatments (sensitivity ranges between 0.81 and 1 and Kappa index ranges between 0.65 and 0.80). However, for variables such as the duration of the treatments and the pesticides used, sensitivity values range between 0.32 and 0.50.ConclusionsThe results suggest that the questionnaire is a valid tool for measuring some items but in order to improve the quality of the exposure assessment the questionnaire was modified, including a question about size of treated areas (as a proxy variable for duration of treatments) and prompt lists were developed to make easier recall by the workers of specific pesticides used in treatments

From planning to performance: the adaptation process as a determinant of outcomes

Currently, teams require adaptation to deal with work demands successfully. However, research concerning team adaptation should necessarily involve a greater empirical effort in defining under which conditions teams prove more adaptable. This article seeks to contribute to the literature by linking plan formulation, plan execution, and team learning behaviors with team outcomes (i.e., team-adaptation perception and objective performance). Participants formed 142 teams, which were involved in structured-problem solving task (i.e. a simulated management competition). Conditional process analysis was used to test a double-mediated relationship. Results show that, although not all parts of the model are directly associated, there is an indirect link from plan formulation to team outcomes through plan execution and team learning behaviors. Our results support the idea of adaptation as a process, providing four ways in which organizations can elicit changes in teams: increasing plan execution, promoting team learning, improving team adaptive behaviors themselves, and building teams composed of members who demonstrate individual adaptability

Influence of Grapevine Leafroll-associated Virus-3 in Mature Plants of Vitis vinifera L. cv Albariño on 110R and 196.17C Rootstocks

The detrimental effects of grapevine leafroll disease (GLD) have been documented mainly in young plantsand little data is available on infected grapevines when they reach maturity. This study examined theinfluence of the rootstock on the effect of GLRaV-3 in a 20-year-old Vitis vinifera cv Albariño vineyard inwhich the virus has been spread by Planococcus ficus. Plants grafted on Richter 110 or Castell 196.17 withsimilar development were analysed for grapevine leafroll-associated viruses. In particular, 25 GLRaV-3-infected and 25 leafroll-free and asymptomatic vines were selected and monitored during a period of threeyears to determine grape yield and must components. Although the virus infection affected plants on bothrootstocks, it caused a greater effect on plants grafted onto 110R, with average accumulated yield losses ofup to 33%, relative to losses of 16% for plants on 196.17C. The sugar content was lower in the must frominfected plants on 110R (-2.1ºBrix) than in the must from plants on 196.17C (-1.5ºBrix). The presence ofthe virus was associated with decreased concentrations of primary amino nitrogen (PAN) and ammonium(NH4+), with the greatest effect for 110R (-35%). As 110R is the most used rootstock in Spain, particularcare must be taken to prevent the transmission of GLRaV-3 to certified virus-free plants on 110R in newvineyards. In sensitive varieties such as Albariño, particularly in areas with an active spread of the virusby mealybugs, grafting on 196.17C seems to minimise the effect that GLD has in a medium to long term

Comparative Analysis of Extrusion Processes by Finite Element Analysis

AbstractExtrusion processes are quite extended in the manufacturing of long products for a wide range of industrial applications. There are different approaches of extrusion processes, depending on either the final shape of the product to obtain or the maximum loading capacity of the equipment to be used. This work presents a comparative study of extrusion processes (solid and cup extrusion), considering both direct and indirect forming conditions and showing the most interesting differences between them. The comparison is realized by Finite Element simulation of the processes, using the code DEFORM F2. The material is a low carbon steel (AISI-1010) and the same extrusion ratio and ram displacement are considered in all cases. By comparing the required forces it can be concluded that required loads are higher in cup extrusion processes than in solid extrusion ones. Regarding the friction load, the maximum contribution due to the die-billet contact in cup extrusion is much higher than in the case of solid extrusion. On the contrary, the maximum friction load contribution due to the container wall is much higher in the case of solid extrusion than in cup extrusion

Applying MILP-based algorithms to automated job-shop scheduling problems in aircraft-part manufacturing

This work presents efficient algorithms based on Mixed-Integer Linear Programming (MILP) for complex job-shop scheduling problems raised in Automated Manufacturing Systems. The aim of this work is to find alternative solution approaches of production and transportation operations in a multi-product multistage production process that can be used to solve industrial-scale problems with reasonable computational effort. The MILP model developed must take into account; dissimilar recipes, single unit per production stage, re-entrant flows, sequence- dependent free transferring times and load transfer movements in a single automated material-handling device. In addition, logical-based strategies are proposed to iteratively find and improve the solutions generated over time. These approaches were tested in different real-world problems appeared in the surfacetreatment process of metal components in aircraft manufacturing industry.Sociedad Argentina de Informática e Investigación Operativ

Applying MILP-based algorithms to automated job-shop scheduling problems in aircraft-part manufacturing

This work presents efficient algorithms based on Mixed-Integer Linear Programming (MILP) for complex job-shop scheduling problems raised in Automated Manufacturing Systems. The aim of this work is to find alternative solution approaches of production and transportation operations in a multi-product multistage production process that can be used to solve industrial-scale problems with reasonable computational effort. The MILP model developed must take into account; dissimilar recipes, single unit per production stage, re-entrant flows, sequence- dependent free transferring times and load transfer movements in a single automated material-handling device. In addition, logical-based strategies are proposed to iteratively find and improve the solutions generated over time. These approaches were tested in different real-world problems appeared in the surfacetreatment process of metal components in aircraft manufacturing industry.Sociedad Argentina de Informática e Investigación Operativ

Applying MILP-based algorithms to automated job-shop scheduling problems in aircraft-part manufacturing

This work presents efficient algorithms based on Mixed-Integer Linear Programming (MILP) for complex job-shop scheduling problems raised in Automated Manufacturing Systems. The aim of this work is to find alternative solution approaches of production and transportation operations in a multi-product multistage production process that can be used to solve industrial-scale problems with reasonable computational effort. The MILP model developed must take into account; dissimilar recipes, single unit per production stage, re-entrant flows, sequence- dependent free transferring times and load transfer movements in a single automated material-handling device. In addition, logical-based strategies are proposed to iteratively find and improve the solutions generated over time. These approaches were tested in different real-world problems appeared in the surfacetreatment process of metal components in aircraft manufacturing industry.Sociedad Argentina de Informática e Investigación Operativ

Edge scaling limits for a family of non-Hermitian random matrix ensembles

A family of random matrix ensembles interpolating between the GUE and the Ginibre ensemble of $n\times n$ matrices with iid centered complex Gaussian entries is considered. The asymptotic spectral distribution in these models is uniform in an ellipse in the complex plane, which collapses to an interval of the real line as the degree of non-Hermiticity diminishes. Scaling limit theorems are proven for the eigenvalue point process at the rightmost edge of the spectrum, and it is shown that a non-trivial transition occurs between Poisson and Airy point process statistics when the ratio of the axes of the supporting ellipse is of order $n^{-1/3}$. In this regime, the family of limiting probability distributions of the maximum of the real parts of the eigenvalues interpolates between the Gumbel and Tracy-Widom distributions.Comment: 44 page