P-Wave Charmed-Strange Mesons

We examine charmed-strange mesons within the framework of the constituent quark model, focusing on the states with L=1. We are particularly interested in the mixing of two spin-states that are involved in $D_{s1}(2536)$ and the recently discovered $D_{sJ}(2460)$. We assume that these two mesons form a pair of states with J=1. These spin-states are mixed by a type of the spin-orbit interaction that violates the total-spin conservation. Without assuming explicit forms for the interactions as functions of the interquark distance, we relate the matrix elements of all relevant spin-dependent interactions to the mixing angle and the observed masses of the L=1 quartet. We find that the spin-spin interaction, among various types of the spin-dependent interactions, plays a particularly interesting role in determining the spin structure of $D_{s1}(2536)$ and $D_{sJ}(2460)$

Spinal V2b neurons reveal a role for ipsilateral inhibition in speed control

The spinal cord contains a diverse array of interneurons that govern motor output. Traditionally, models of spinal circuits have emphasized the role of inhibition in enforcing reciprocal alternation between left and right sides or flexors and extensors. However, recent work has shown that inhibition also increases coincident with excitation during contraction. Here, using larval zebrafish, we investigate the V2b (Gata3+) class of neurons, which contribute to flexor-extensor alternation but are otherwise poorly understood. Using newly generated transgenic lines we define two stable subclasses with distinct neurotransmitter and morphological properties. These V2b subclasses synapse directly onto motor neurons with differential targeting to speed-specific circuits. In vivo, optogenetic manipulation of V2b activity modulates locomotor frequency: suppressing V2b neurons elicits faster locomotion, whereas activating V2b neurons slows locomotion. We conclude that V2b neurons serve as a brake on axial motor circuits. Together, these results indicate a role for ipsilateral inhibition in speed control

Remoção de corantes reativos contendo grupos vinilsulfona e triazina por adsorção e coagulação/floculação com quitosana

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Curso de Pós-Graduação em QuímicaRemoção de corantes reativos por processo de adsorção e coagulação/floculação empregando o biopolímero quitosana. Os estudos foram realizados com os corantes reativos individualmente e com efluentes fornecidos pela Buettner e Anglian Water (Brusque). A quitosana mostrou-se uma excelente opção para tratamento de efluentes residuários têxteis, aliadas às vantagens ecológicas ao meio ambient

Vsx2 in the zebrafish retina: restricted lineages through derepression

<p>Abstract</p> <p>Background</p> <p>The neurons in the vertebrate retina arise from multipotent retinal progenitor cells (RPCs). It is not clear, however, which progenitors are multipotent or why they are multipotent.</p> <p>Results</p> <p>In this study we show that the homeodomain transcription factor Vsx2 is initially expressed throughout the retinal epithelium, but later it is downregulated in all but a minor population of bipolar cells and all Müller glia. The Vsx2-negative daughters of Vsx2-positive RPCs divide and give rise to all other cell types in the retina. Vsx2 is a repressor whose targets include transcription factors such as Vsx1, which is expressed in the progenitors of distinct non-Vsx2 bipolars, and the basic helix-loop-helix transcription factor Ath5, which restricts the fate of progenitors to retinal ganglion cells, horizontal cells, amacrine cells and photoreceptors fates. Foxn4, expressed in the progenitors of amacrine and horizontal cells, is also negatively regulated by Vsx2.</p> <p>Conclusion</p> <p>Our data thus suggest Vsx2-positive RPCs are fully multipotent retinal progenitors and that when Vsx2 is downregulated, Vsx2-negative progenitors escape Vsx2 repression and so are able to express factors that restrict lineage potential.</p

Measures of Task Effects: Comparison among Negotiation of Meaning, Corrective Feedback, and Language-Related Episode

A growing number of task studies have examined which tasks provide increased focus in language forms incidents. Researchers have used negotiation of meaning, corrective feedback. and language-related episodes (LREs) as measures of focus. However, each measure relates to different aspects of dialogue. Therefore, the results of task studies may differ depending on the measure employed. The present study was conducted to investigate which measure extracts more focus-on-form incidents regarding grammar. The participants were 20 low-intermediate-level and 14 high-intermediate-level students undertaking an intensive Japanese-language program in the United States. Using two conversation tasks, I made a comparison of how the frequency of focus-on-form incidents differed with the three measures. I found that each measure resulted in a different number of focus-on-form incidents. Regardless of the students' ability level, LREs produced the greatest number of focus-on-form incidents. Negotiation of meaning has been utilized as a measure for focus-on-form incidents in many task studies; however, it extracted hardly any focus-on-form incidents in the present investigation