Orientation and symmetries of Alexandrov spaces with applications in positive curvature

We develop two new tools for use in Alexandrov geometry: a theory of ramified orientable double covers and a particularly useful version of the Slice Theorem for actions of compact Lie groups. These tools are applied to the classification of compact, positively curved Alexandrov spaces with maximal symmetry rank.Comment: 34 pages. Simplified proofs throughout and a new proof of the Slice Theorem, correcting omissions in the previous versio

Enfermeiras americanas do Serviço Especial de Saúde Pública e a formação de recursos humanos na Enfermagem Brasileira

RESUMO Objetivo Historicizar as mudanças na formação de recursos humanos em enfermagem no Brasil, no período de 1942 a 1961, a partir da presença de 35 enfermeiras americanas designadas para trabalhar em cooperação com o SESP. Método O estudo utilizou como fontes relatórios redigidos pelas enfermeiras, que descrevem suas impressões, sugestões e atividades desenvolvidas no país, e foram analisadas a partir da análise de discurso de Michel Foucault. Resultados O período mencionado foi marcado pela presença americana nos projetos de enfermagem desenvolvidos pelo Serviço Especial de Saúde Pública (SESP). Os discursos indicaram que o período foi marcado por muitas mudanças na enfermagem brasileira, em especial no que diz respeito à captação e formação de recursos humanos para a profissão. Conclusão Pode-se afirmar que elas, através de seus discursos e influência, foram centrais para a consolidação de um novo paradigma na formação de profissionais de enfermagem no Brasil

Spelling improvement through letter-sound and whole-word training in two multilingual Greek- and English- speaking children

Case studies of two children with spelling difficulty are reported. LK was multilingual and ED bilingual. A training programme that targeted phonic decoding (or sublexical) spelling processes was conducted with both children. Immediate and delayed post-training assessments showed improvement in spelling nonwords for LK but not for ED. Training that targeted whole word (or lexical) spelling processes was then conducted with ED. Improvement in spelling of irregular words (a marker for lexical spelling processes) was observed. Research into literacy difficulties with multilingual children is sparse, although multilingualism is increasingly widespread. Up to now theoretically based training studies have focused on monolingual children and results were promising. The present findings indicate that theoretically based training programmes for literacy difficulties can also be effective for multilingual children

Recruitment and Consolidation of Cell Assemblies for Words by Way of Hebbian Learning and Competition in a Multi-Layer Neural Network

Current cognitive theories postulate either localist representations of knowledge or fully overlapping, distributed ones. We use a connectionist model that closely replicates known anatomical properties of the cerebral cortex and neurophysiological principles to show that Hebbian learning in a multi-layer neural network leads to memory traces (cell assemblies) that are both distributed and anatomically distinct. Taking the example of word learning based on action-perception correlation, we document mechanisms underlying the emergence of these assemblies, especially (i) the recruitment of neurons and consolidation of connections defining the kernel of the assembly along with (ii) the pruning of the cell assembly’s halo (consisting of very weakly connected cells). We found that, whereas a learning rule mapping covariance led to significant overlap and merging of assemblies, a neurobiologically grounded synaptic plasticity rule with fixed LTP/LTD thresholds produced minimal overlap and prevented merging, exhibiting competitive learning behaviour. Our results are discussed in light of current theories of language and memory. As simulations with neurobiologically realistic neural networks demonstrate here spontaneous emergence of lexical representations that are both cortically dispersed and anatomically distinct, both localist and distributed cognitive accounts receive partial support

Relative meaning frequencies for 578 homonyms in two Spanish dialects: A cross-linguistic extension of the English eDom norms

Relative meaning frequency is a critical factor to consider in studies of semantic ambiguity. In this work, we examined how this measure may change across the European and Rioplatense dialects of Spanish, as well as how the overall distributional properties differ between Spanish and English, using a computer-assisted norming approach based on dictionary definitions (Armstrong, Tokowicz, & Plaut, 2012). The results showed that the two dialects differ considerably in terms of the relative meaning frequencies of their constituent homonyms, and that the overall distributions of relative frequencies vary considerably across languages, as well. These results highlight the need for localized norms to design powerful studies of semantic ambiguity and suggest that dialectal differences may be responsible for some discrepant effects related to homonymy. In quantifying the reliability of the norms, we also established that as few as seven ratings are needed to converge on a highly stable set of ratings. This approach is therefore a very practical means of acquiring essential data in studies of semantic ambiguity, relative to past approaches, such as those based on the classification of free associates. The norms also present new possibilities for studying semantic ambiguity effects within and between populations who speak one or more languages. The norms and associated software are available for download at http://edom.cnbc.cmu.edu/ or http://www.bcbl.eu/databases/edom/