Chess databases as a research vehicle in psychology : modeling large data

The game of chess has often been used for psychological investigations, particularly in cognitive science. The clear-cut rules and well-defined environment of chess provide a model for investigations of basic cognitive processes, such as perception, memory, and problem solving, while the precise rating system for the measurement of skill has enabled investigations of individual differences and expertise-related effects. In the present study, we focus on another appealing feature of chess—namely, the large archive databases associated with the game. The German national chess database presented in this study represents a fruitful ground for the investigation of multiple longitudinal research questions, since it collects the data of over 130,000 players and spans over 25 years. The German chess database collects the data of all players, including hobby players, and all tournaments played. This results in a rich and complete collection of the skill, age, and activity of the whole population of chess players in Germany. The database therefore complements the commonly used expertise approach in cognitive science by opening up new possibilities for the investigation of multiple factors that underlie expertise and skill acquisition. Since large datasets are not common in psychology, their introduction also raises the question of optimal and efficient statistical analysis. We offer the database for download and illustrate how it can be used by providing concrete examples and a step-by-step tutorial using different statistical analyses on a range of topics, including skill development over the lifetime, birth cohort effects, effects of activity and inactivity on skill, and gender differences

Aumento gradual da variabilidade de prática: efeito na aprendizagem da estrutura e na parametrização da habilidade

Tradicionalmente, na aprendizagem de habilidades motoras a prática tem sido estruturada de forma constante, em blocos, seriada ou aleatória. Tem sido proposta a superioridade da prática variada sobre a prática constante bem como da prática aleatória e seriada sobre a prática em blocos. Atualmente tem sido observada uma especificidade do tipo de prática: a prática constante auxilia na formação de uma estrutura de movimento, especialmente no inicio da aprendizagem e a prática variada na melhora da parametrização. O presente estudo investigou diferentes regimes de prática e a sua combinaçao numa sequência que fornece um aumento gradual de variabilidade (constante, blocos e aleatório) na aquisição de habilidades motoras. A amostra foi distribuida em quatro grupos (n = 10): CCC (constante), BBB (blocos), AAA (aleatório) e CBA (constante-blocos-aleatório). O experimenta foi dividido em fase de aquisição e teste de transferência. Na fase de aquisição a tarefa foi pressionar teclas numéricas do teclado de um computador em uma sequência (2, 8, 6, 4) com o dedo indicador, com tempo relativo entre os componentes especificado (22,2%, 44,4% e 33,3%) e com os seguintes tempos totais (700, 900 e 1100 ms) estabelecidos conforme o delineamento experimental. Os resultados do teste demonstraram superioridade dos grupos CBA e AAA na medida de erro absoluta, dos grupos CCC e BBB na medida de erro relativo e dos grupos CCC, BBB e CBA na medida de variabilidade de erro relativo. Tais resultados demonstram que os regimes de prática que forneceram menor variabilidade conduziram ao aprendizado de uma estrutura de movimento, enquanto que as que forneceram maior variabilidade resultaram na melhora da capacidade de parametrização.Traditionally, on the learning of motor skill practice has been scheduled in constant, blocked, serial or random fashion. A superiority of variable over constant practice has been suggested as well as random and serial practices over blocked practice. Recently a specificity of the type of practice has been observed: constant practice helps the formation of a movement structure, especially in the early learning, and the variable practice improves parameterization. This study investigated different practice schedules and their combinations in a sequence that provides a gradual increment of variability (constant, blocked, and random) in the acquisition of motor skills. Participants were divided into four groups (n = 10): CCC [constant), BBB (blocked), RRR (random) and CBR (constant-blocked-random). The experiment consisted of an acquisition phase and a transfer test. In the acquisition phase the task comprised pressing a numeric keyboard in a given sequence (2, 8, 6, 4) with the index finger, with fixed relative timing among presses (22.2%, 44.4% and 33.3%) and specific total times (700, 900 and 1100 ms) determined by the experimental design. The test results showed a superiority of CBR and RRR groups in the absolute error measure, of CCC and BBB groups in the relative error measure, and CCC, BBB and CBR groups in the variability of relative error measure. These results evidence the practice schedules that provided smaller variability led to the learning of a movement structure, whereas the ones that provided greater variability culminated in the improvement in parameterization

Post weaning diarrhea in pigs: risk factors and non‑colistin‑based control strategies

Post-weaning diarrhea (PWD) is one of the most serious threats for the swine industry worldwide. It is commonly associated with the proliferation of enterotoxigenic Escherichia coli in the pig intestine. Colistin, a cationic antibiotic, is widely used in swine for the oral treatment of intestinal infections caused by E. coli, and particularly of PWD. However, despite the effectiveness of this antibiotic in the treatment of PWD, several studies have reported high rates of colistin resistant E. coli in swine. Furthermore, this antibiotic is considered of very high importance in humans, being used for the treatment of infections due to multidrug-resistant (MDR) Gram-negative bacteria (GNB). Moreover, the recent discovery of the mcr-1 gene encoding for colistin resistance in Enterobacteriaceae on a conjugative stable plasmid has raised great concern about the possible loss of colistin effectiveness for the treatment of MDR-GNB in humans. Consequently, it has been proposed that the use of colistin in animal production should be considered as a last resort treatment only. Thus, to overcome the economic losses, which would result from the restriction of use of colistin, especially for prophylactic purposes in PWD control, we believe that an understanding of the factors contributing to the development of this disease and the putting in place of practical alternative strategies for the control of PWD in swine is crucial. Such alternatives should improve animal gut health and reduce economic losses in pigs without promoting bacterial resistance. The present review begins with an overview of risk factors of PWD and an update of colistin use in PWD control worldwide in terms of quantities and microbiological outcomes. Subsequently, alternative strategies to the use of colistin for the control of this disease are described and discussed. Finally, a practical approach for the control of PWD in its various phases is proposed

Quantitative muscle strength assessment in duchenne muscular dystrophy: longitudinal study and correlation with functional measures

The aim of this study was to perform a longitudinal assessment using Quantitative Muscle Testing (QMT) in a cohort of ambulant boys affected by Duchenne muscular dystrophy (DMD) and to correlate the results of QMT with functional measures. This study is to date the most thorough long-term evaluation of QMT in a cohort of DMD patients correlated with other measures, such as the North Star Ambulatory Assessment (NSAA) or three 6-min walk test (6MWT)