Influence of contrast and coherence on the temporal dynamics of binocular motion rivalry

Contains fulltext : 125980.pdf (publisher's version ) (Open Access)Levelt's four propositions (L1-L4), which characterize the relation between changes in "stimulus strength" in the two eyes and percept alternations, are considered benchmark for binocular rivalry models. It was recently demonstrated that adaptation mutual-inhibition models of binocular rivalry capture L4 only in a limited range of input strengths, predicting an increase rather than a decrease in dominance durations with increasing stimulus strength for weak stimuli. This observation challenges the validity of those models, but possibly L4 itself is invalid. So far, L1-L4 have been tested mainly by varying the contrast of static stimuli, but since binocular rivalry breaks down at low contrasts, it has been difficult to study L4. To circumvent this problem, and to test if the recent revision of L2 has more general validity, we studied changes in binocular rivalry evoked by manipulating coherence of oppositely-moving random-dot stimuli in the two eyes, and compared them against the effects of stimulus contrast. Thirteen human observers participated. Both contrast and coherence manipulations in one eye produced robust changes in both eyes; dominance durations of the eye receiving the stronger stimulus increased while those of the other eye decreased, albeit less steeply. This is inconsistent with L2 but supports its revision. When coherence was augmented in both eyes simultaneously, dominance durations first increased at low coherence, and then decreased for further increases in coherence. The same held true for the alternation periods. The initial increase in dominance durations was absent in the contrast experiments, but with coherence manipulations, rivalry could be tested at much lower stimulus strengths. Thus, we found that L4, like L2, is only valid in a limited range of stimulus strengths. Outside that range, the opposite is true. Apparent discrepancies between contrast and coherence experiments could be fully reconciled with adaptation mutual-inhibition models using a simple input transfer-function

Percepção materna do estado nutricional de crianças de creches de cidade do Sul do Brasil

OBJETIVO: Avaliar a prevalência e os fatores associados ao erro na percepção do estado nutricional das crianças de creches públicas e privadas de Balneário Camboriú (SC) por parte das mães ou responsáveis. MÉTODOS: Estudo transversal com a seleção de amostra em duplo estágio (n=589). A coleta de dados incluiu medidas antropométricas e questionário com variáveis infantis e maternas. Foram calculadas as razões de prevalência e intervalos de confiança de 95% (IC 95%), por meio da Regressão de Poisson, ajustada para delineamentos complexos. RESULTADOS: Foram avaliadas 493 crianças (83,7%). A distribuição em relação ao sexo infantil mostrou-se homogênea. As mães foram as principais respondentes dos questionários (95,7%), apresentaram em geral cor de pele branca e escolaridade média. A prevalência de erro na classificação do estado nutricional infantil foi de 18,9% (IC 95% 15,5-22,4%). Após análise ajustada, sobrepeso (RP 4,8 IC 95% 3,8-7,1) ou desnutrição infantil (RP 4,6 IC 95% 2,8-7,7) e cor da pele do responsável não branca (RP 1,7 IC 95% 1,1-2,6) foram variáveis associadas à maior prevalência do desfecho, enquanto idade do responsável entre 24 e 35 anos (RP 0,5 IC 95% 0,3-0,8), maior renda (RP 0,6 IC 95% 0,4-0,9) e obesidade do responsável (RP 0,3 IC 95% 0,1-1,0) atuaram em direção oposta. CONCLUSÃO: A prevalência de erro foi similar àquela observada em outros estudos e esteve associada a variáveis composicionais maternas e ao estado nutricional infantil

Does entrepreneurial leadership foster creativity among employees and team?: The mediating role of creative efficacy beliefs

The purpose of this study is to gain a better understanding of how entrepreneurial leadership relates to workplace creativity in organizations from the compatibility perspective. Drawing on social cognitive theory, we propose that individual creative self-efficacy and team creative efficacy beliefs mediate the relationships between entrepreneurial leadership and individual and team creativity. This study examines the relationship between entrepreneurial leadership and creativity through creative efficacy. Survey data were collected from multiple sources, including 43 leaders and 237 employees in eight Chinese companies. Cross-level relationships are tested by means of a hierarchical linear modeling analysis (HLM). The results reveal that entrepreneurial leadership is positively related to employee and team creativity, and these relationships are found to be mediated by both employee creative self efficacy and team creative efficacy. Furthermore, team creative efficacy is found to exert a cross-level mediating influence on the entrepreneurial leadership-employee creativity relationship. This study suggests that employees and teams led by entrepreneurial leaders are likely to produce creative outcomes. The findings further confirm the important role of creative efficacy beliefs in explaining how entrepreneurial leadership relates to employee and team creativity, as such beliefs serve as a within-level and cross-level mediating mechanism in these relationships. Our study is among the first to empirically investigate the concept of entrepreneurial leadership in a broader organizational context. We examine how entrepreneurial leadership contributes to workplace creativity. Our study shows that creative efficacy beliefs exert both within-level and cross-level mediating influences in the entrepreneurial leadership-creativity relation