Reproducibility in the absence of selective reporting : An illustration from large-scale brain asymmetry research

Altres ajuts: Max Planck Society (Germany).The problem of poor reproducibility of scientific findings has received much attention over recent years, in a variety of fields including psychology and neuroscience. The problem has been partly attributed to publication bias and unwanted practices such as p-hacking. Low statistical power in individual studies is also understood to be an important factor. In a recent multisite collaborative study, we mapped brain anatomical left-right asymmetries for regional measures of surface area and cortical thickness, in 99 MRI datasets from around the world, for a total of over 17,000 participants. In the present study, we revisited these hemispheric effects from the perspective of reproducibility. Within each dataset, we considered that an effect had been reproduced when it matched the meta-analytic effect from the 98 other datasets, in terms of effect direction and significance threshold. In this sense, the results within each dataset were viewed as coming from separate studies in an "ideal publishing environment," that is, free from selective reporting and p hacking. We found an average reproducibility rate of 63.2% (SD = 22.9%, min = 22.2%, max = 97.0%). As expected, reproducibility was higher for larger effects and in larger datasets. Reproducibility was not obviously related to the age of participants, scanner field strength, FreeSurfer software version, cortical regional measurement reliability, or regional size. These findings constitute an empirical illustration of reproducibility in the absence of publication bias or p hacking, when assessing realistic biological effects in heterogeneous neuroscience data, and given typically-used sample sizes

Migration decisions, agrarian structure, and gender: the case of Ecuador.

This article briefly reviews the literature on migration in Latin America and examines migration decision making in Ecuador. Aggregate data are obtained from the 1974 census of agriculture and population for cantones. Individual level data are obtained from the 1982 census of population. Migration refers to all census persons who recorded differences in their present and previous place of residence during 1974-82. Migration is modeled as dependent upon gender, age, education, marital status, income at origin and at destination, and population pressure or agrarian reform. Logistic model findings indicate that migration decisions are influenced by individual characteristics of migrants and contextual variables. Migration varied by gender. The results confirm Todaro's hypothesis that the probability of migrating is related to income differences between place of destination and origin, but only for males. Findings suggest that females migrate for primary reasons other than economic ones. The probability of migration was greater with increased levels of education. The decision to migrate was affected by quality of life differences, such as literacy rates and levels of urbanization. The probability of migration was reduced by the effects of land reform. Population pressure had a significant effect in increasing migration. The effects of land reform differ from findings in Mexico by William E. Cole and Richard D. Sanders. Land reforms were initiated in 1964 in Ecuador, but by 1974 there was still considerable inequality in land distribution and increased population pressure. Traditional haciendas were modernized, and peasants increased their dependency on non-farm income

Análise de indicadores ambientais no reservatório do Passaúna Analysis of environmental indicators in Passaúna reservoir

A importância dos indicadores ambientais está associada à sua utilização como instrumentos para a sociedade avaliar a própria evolução. No contexto ambiental, indicadores são parâmetros representativos, concisos e fáceis de interpretar utilizados para ilustrar as principais características de uma determinada região. O presente trabalho apresenta uma proposta de indicadores ambientais para o reservatório do Passaúna, um dos principais mananciais de Curitiba, com base em 14 parâmetros. Apresenta, também, uma proposta de determinação de um índice de comprometimento ambiental (ICA) com base na importância relativa de cada um dos potenciais poluidores. Apresenta-se, aqui, um exemplo de determinação do ICA, considerando os dados disponíveis para seis parâmetros, concluindo-se que o reservatório do Passaúna apresenta forte comprometimento ambiental.<br>The relevance of environmental indicators is associated with their use as tools with which society evaluates its own evolution. In the environmental context, indicators are parameters which are representative of the processes involved, are concise and easy to interpret, and which are used to represent the main characteristics of a certain area. The present work proposes a set of environmental indicators for the Passaúna reservoir, one of the main sources of drinking water in Curitiba, Brazil, based on 14 parameters. This paper also presents a proposal for the determination of an environmental stress index (ICA) based on the relative importance of pollution threats. An example is shown, considering the available data for six parameters, which indicates that the Passaúna reservoir is under strong environmental stress

Relationship between morphology and trophic ecology in an assemblage of passerine birds in riparian forests of the Paraná River (Argentina)

We describe the ecomorphology of an assemblage of bird species found in riparian forests of the Middle Paraná River, Argentina. We sought to determine (1) the more important morphological characteristics that separate coexisting species, (2) whether such separation was related to the trophic ecology of each species and (3) whether a priori guilds showed morphological similarity. We tested the hypotheses that (a) a species' morphology is related to the trophic ecology of that species and (b) that species of a priori guilds are morphometrically more similar to each other than to species of different a priori guilds. For this, we considered an assemblage of 29 species of birds from riparian forest that were sampled with mist nets during the 2011 and 2014 breeding seasons. We obtained morphometric measurements of captured individuals and supplemented those data with measurements from museum specimens. Trophic characterisation (diet and trophic microhabitat) was based on a literature review. Results showed a separation of bird species as a function of variables related to trophic ecology (diets and trophic microhabitats) and morphology. After controlling for phylogenetic constraint, species' morphology partially reflected the trophic ecology of the species, supporting the central hypothesis of the ecomorphological discipline and showing that the use of trophic and morphometric data provides complementary data to improve the guild organisation of riparian bird assemblages.Fil: Quiroga, Virginia Mariela. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Lorenzón, Rodrigo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Maglier, Gisela. Universidad Nacional del Litoral; ArgentinaFil: Ronchi Virgolini, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Autónoma de Entre Ríos; Argentin