A Thalamic Reticular Circuit for Head Direction Cell Tuning and Spatial Navigation.

As we navigate in space, external landmarks and internal information guide our movement. Circuit and synaptic mechanisms that integrate these cues with head-direction (HD) signals remain, however, unclear. We identify an excitatory synaptic projection from the presubiculum (PreS) and the multisensory-associative retrosplenial cortex (RSC) to the anterodorsal thalamic reticular nucleus (TRN), so far classically implied in gating sensory information flow. In vitro, projections to TRN involve AMPA/NMDA-type glutamate receptors that initiate TRN cell burst discharge and feedforward inhibition of anterior thalamic nuclei. In vivo, chemogenetic anterodorsal TRN inhibition modulates PreS/RSC-induced anterior thalamic firing dynamics, broadens the tuning of thalamic HD cells, and leads to preferential use of allo- over egocentric search strategies in the Morris water maze. TRN-dependent thalamic inhibition is thus an integral part of limbic navigational circuits wherein it coordinates external sensory and internal HD signals to regulate the choice of search strategies during spatial navigation

Studying changes in the practice of two teachers developing assessment for learning

This paper describes changes in the practice of two teachers, observed over an eighteen month period, who were participating in a study intended to support teachers in developing their use of assessment in support of learning. The design of the intervention allowed each teacher to choose for themselves which aspects of their practice to develop. Analysis of lesson observations, journal entries and interviews indicate that both teachers were keen to change their practice, but were concerned about the disruption to their established routines, and in particular about the potential for loss of control of their classes. Both teachers did effect significant changes in their classrooms, but these tended to be developments of existing preferred ways of working, rather than radical innovations. In conclusion, it is suggested that to be most effective, teacher professional development needs to be structured strongly enough to afford teacher growth, but flexible enough to allow different teachers to take their practice in different ways

Competências profissionais de professores de matemática do ensino médio valorizadas por uma boa escola: a supremacia da cultura da performatividade

Este artigo apresenta alguns resultados de uma pesquisa realizada em uma escola que obteve um ótimo desempenho no ENEM/2009. Os principais objetivos foram investigar e analisar quais competências profissionais de professores de Matemática do ensino médio são consideradas relevantes por essa instituição de ensino e qual a influência da cultura da performatividade no trabalho desses docentes. Para isso, entrevistamos a coordenadora, a supervisora e os quatro professores do ensino médio da instituição investigada. Verificamos que as competências mais valorizadas são influenciadas diretamente pela necessidade de obtenção de bons resultados em avaliações internas e externas. São elas: administrar o tempo, manter-se atualizado quanto às avaliações externas e relacionar-se bem com os alunos. Também constatamos que boa parte das ações da equipe gestora consiste em alinhar o corpo docente, objetivando a aprovação de seus estudantes nos mais concorridos exames vestibulares do país

Increased Hydrogen Production by Genetic Engineering of Escherichia coli

Escherichia coli is capable of producing hydrogen under anaerobic growth conditions. Formate is converted to hydrogen in the fermenting cell by the formate hydrogenlyase enzyme system. The specific hydrogen yield from glucose was improved by the modification of transcriptional regulators and metabolic enzymes involved in the dissimilation of pyruvate and formate. The engineered E. coli strains ZF1 (ΔfocA; disrupted in a formate transporter gene) and ZF3 (ΔnarL; disrupted in a global transcriptional regulator gene) produced 14.9, and 14.4 µmols of hydrogen/mg of dry cell weight, respectively, compared to 9.8 µmols of hydrogen/mg of dry cell weight generated by wild-type E. coli strain W3110. The molar yield of hydrogen for strain ZF3 was 0.96 mols of hydrogen/mol of glucose, compared to 0.54 mols of hydrogen/mol of glucose for the wild-type E. coli strain. The expression of the global transcriptional regulator protein FNR at levels above natural abundance had a synergistic effect on increasing the hydrogen yield in the ΔfocA genetic background. The modification of global transcriptional regulators to modulate the expression of multiple operons required for the biosynthesis of formate hydrogenlyase represents a practical approach to improve hydrogen production