53 research outputs found
Segmented Aperture Interferometric Nulling Testbed (SAINT) II: Component Systems Update
"This work presents updates to the coronagraph and telescope components of the Segmented Aperture Interfer-ometric Nulling Testbed (SAINT). The project pairs an actively-controlled macro-scale segmented mirror withthe Visible Nulling Coronagraph (VNC) towards demonstrating capabilities for the future space observatoriesneeded to directly detect and characterize a significant sample of Earth-sized worlds around nearby stars inthe quest for identifying those which may be habitable and possibly harbor life. Efforts to improve the VNCwavefront control optics and mechanisms towards repeating narrowband results are described. A narrative isprovided for the design of new optical components aimed at enabling broadband performance. Initial work withthe hardware and software interface for controlling the segmented telescope mirror is also presented.
Promoting fit bodies, healthy eating and physical activity among Indigenous Australian men: a study protocol
Background: Overall the physical health of Indigenous men is among the worst in Australia. Research has indicated that modifiable lifestyle factors, such as poor nutrition and physical inactivity, appear to contribute strongly to these poor health conditions. To effectively develop and implement strategies to improve the health of Australia’s Indigenous peoples, a greater understanding is needed of how Indigenous men perceive health, and how they view and care for their bodies. Further, a more systematic understanding of how sociocultural factors affect their health attitudes and behaviours is needed. This article presents the study protocol of a communitybased investigation into the factors surrounding the health and body image of Indigenous Australian men.Methods and design: The study will be conducted in a collaborative manner with Indigenous Australian men using a participatory action research framework. Men will be recruited from three locations around Australia (metropolitan, regional, and rural) and interviewed to understand their experiences and perspectives on a number of issues related to health and health behaviour. The information that is collected will be analysed using modified grounded theory and thematic analysis. The results will then be used to develop and implement community events in each location to provide feedback on the findings to the community, promote health enhancing strategies, and determine future action and collaboration.Discussion: This study will explore both risk and protective factors that affect the health of Indigenous Australian men. This knowledge will be disseminated to the wider Indigenous community and can be used to inform future health promotion strategies. The expected outcome of this study is therefore an increased understanding of health and health change in Indigenous Australian men, the development of strategies that promote healthy eating and positive patterns of physical activity and, in the longer term, more effective and culturally-appropriate interventions to improve health.<br /
Neurophysiological Defects and Neuronal Gene Deregulation in Drosophila mir-124 Mutants
miR-124 is conserved in sequence and neuronal expression across the animal kingdom and is predicted to have hundreds of mRNA targets. Diverse defects in neural development and function were reported from miR-124 antisense studies in vertebrates, but a nematode knockout of mir-124 surprisingly lacked detectable phenotypes. To provide genetic insight from Drosophila, we deleted its single mir-124 locus and found that it is dispensable for gross aspects of neural specification and differentiation. On the other hand, we detected a variety of mutant phenotypes that were rescuable by a mir-124 genomic transgene, including short lifespan, increased dendrite variation, impaired larval locomotion, and aberrant synaptic release at the NMJ. These phenotypes reflect extensive requirements of miR-124 even under optimal culture conditions. Comparison of the transcriptomes of cells from wild-type and mir-124 mutant animals, purified on the basis of mir-124 promoter activity, revealed broad upregulation of direct miR-124 targets. However, in contrast to the proposed mutual exclusion model for miR-124 function, its functional targets were relatively highly expressed in miR-124–expressing cells and were not enriched in genes annotated with epidermal expression. A notable aspect of the direct miR-124 network was coordinate targeting of five positive components in the retrograde BMP signaling pathway, whose activation in neurons increases synaptic release at the NMJ, similar to mir-124 mutants. Derepression of the direct miR-124 target network also had many secondary effects, including over-activity of other post-transcriptional repressors and a net incomplete transition from a neuroblast to a neuronal gene expression signature. Altogether, these studies demonstrate complex consequences of miR-124 loss on neural gene expression and neurophysiology
Deliberation, Unjust Exclusion, and the Rhetorical Turn
Theories of deliberative democracy have faced the charge of leading to the unjust exclusion of voices from public deliberation. The recent rhetorical turn in deliberative theory aims to respond to this charge. I distinguish between two variants of this response: the supplementing approach and the systemic approach. On the supplementing approach, rhetorical modes of political speech may legitimately supplement the deliberative process, for the sake of those excluded from the latter. On the systemic approach, rhetorical modes of political speech are legitimate within public deliberation, just so long as they result in net benefits to the deliberative system. I argue that neither of these two approaches adequately meets the unjust exclusion charge. Whereas the supplementing approach does not go far enough to incorporate rhetorical speech into public deliberation, the systemic approach goes too far by legitimizing forms of rhetoric that risk only exacerbating the problem of unjust exclusion. More constructively, I draw on Aristotle’s conception of rhetoric, as an art (technē) that is a counterpart to dialectic, to argue for a constitutive approach to rhetoric. I show how this approach provides a more expansive notion of deliberation that remains normatively orientated
NMR Solution Structure of α-Conotoxin ImI and Comparison to Other Conotoxins Specific for Neuronal Nicotinic Acetylcholine Receptors †
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