Roles of ETS Genes ER81 and PEA3 in the Development of the Monosynaptic Stretch Reflex Circuit

The monosynaptic stretch reflex circuit consists of two neural cell types, sensory neurons and alpha-motoneurons. Ia afferents form synaptic connections with motoneurons projecting to the same or synergistic muscles, but not with motoneurons projecting to unrelated muscles. These synaptic connections form appropriately from the outset suggesting that they may be controlled by expression of specific adhesion molecules in matching sensory and motor neurons. Recently, two ETS-family transcription factors (Er81 and PEA3) were shown to be expressed in subsets of motoneurons and muscle sensory neurons. The expression patterns of these factors suggested that ETS genes might regulate the formation of synaptic connections between Ia afferents and motoneurons. This thesis explores the roles of Er81 and PEA3 in the formation of the stretch reflex circuit inferred from a study of Er81 and PEA3 null-mutant mice.Analysis of Er81 null-mutant mice revealed that Er81 controls a late step in Ia afferent axon guidance. Ia afferents induce the development of muscle spindles in the periphery and project axons into the spinal cord, but fail to grow axon collaterals into the ventral spinal cord where normally strong monosynaptic connections are formed with motoneurons. Consequently, monosynaptic Ia afferent inputs to motoneurons are greatly reduced in these mice. This severe phenotype precluded determination of whether or not the pattern of remaining Ia afferent inputs was normal.Intracellular recordings from quadriceps and obturator motoneurons in PEA3 null-mutants, however, revealed that functionally appropriate patterns of Ia afferent input to motoneurons develop normally in the absence of PEA3. PEA3 mutant mice demonstrated a role for PEA3 in the formation of a specific motor pool. Cutaneous maximus muscle motoneurons normally express PEA3. In PEA3 mutants, the majority of these motoneurons fail to migrate and coalesce appropriately into a discrete motor pool. These motoneurons also fail to project axons into the c. maximus muscle. Consequently, the muscle is atrophic.Thus, Er81 and PEA3 contribute to key developmental stages in the formation of the stretch reflex circuit: the growth of Ia afferents axons toward motoneurons and the formation of appropriate motor pool targets

Recent advancements in monolithic AlGaAs/GaAs solar cells for space applications

High efficiency, two terminal, multijunction AlGaAs/GaAs solar cells were reproducibly made with areas of 0.5 sq cm. The multiple layers in the cells were grown by Organo Metallic Vapor Phase Epitaxy (OMVPE) on GaAs substrates in the n-p configuration. The upper AlGaAs cell has a bandgap of 1.93 eV and is connected in series to the lower GaAs cell (1.4 eV) via a metal interconnect deposited during post-growth processing. A prismatic coverglass is installed on top of the cell to reduce obscuration caused by the gridlines. The best 0.5 sq cm cell has a two terminal efficiency of 23.0 pct. at 1 sun, air mass zero (AM0) and 25 C. To date, over 300 of these cells were grown and processed for a manufacturing demonstration. Yield and efficiency data for this demonstration are presented. As a first step toward the goal of a 30 pct. efficient cell, a mechanical stack of the 0.5 sq cm cells described above, and InGaAsP (0.95 eV) solar cells was made. The best two terminal measurement to date yields an efficiency of 25.2 pct. AM0. This is the highest reported efficiency of any two terminal, 1 sun space solar cell

The 25 percent-efficient GaAs Cassegrainian concentrator cell

Very high-efficiency GaAs Cassegrainian solar cells have been fabricated in both the n-p and p-n configurations. The n-p configuration exhibits the highest efficiency at concentration, the best cells having an efficiency eta of 24.5 percent (100X, AM0, temperature T = 28 C). Although the cells are designed for operation at this concentration, peak efficiency is observed near 300 suns (eta = 25.1 percent). To our knowledge, this is the highest reported solar cell efficiency for space applications. The improvement in efficiency over that reported at the previous SPRAT conference is attributed primarily to lower series resistance and improved grid-line plating procedures. Using previously measured temperature coefficients, researchers estimate that the n-p GaAs cells should deliver approximately 22.5 percent efficiency at the operating conditions of 100 suns and T = 80 C. This performance exceeds the NASA program goal of 22 percent for the Cassegrainian cell. One hundred Cassegrainian cells have been sent to NASA as deliverables, sixty-eight in the n-p configuration and thirty-two in the p-n configuration

Drivers of taxonomic bias in conservation research : a global analysis of terrestrial mammals

Scientific knowledge of species and the ecosystems they inhabit is the cornerstone of modern conservation. However, research effort is not spread evenly among taxa (taxonomic bias), which may constrain capacity to identify conservation risk and to implement effective responses. Addressing such biases requires an understanding of factors that promote or constrain the use of a particular species in research projects. To this end, we quantified conservation science knowledge of the world's extant non-marine mammal species (n = 4108) based on the number of published documents in journals indexed on Clarivate Analytics' Web of Science (TM). We use an innovative hurdle model approach to assess the relative importance of several ecological, biogeographical and cultural factors for explaining variation in research production between species. The most important variable explaining the presence/absence of conservation research was scientific capacity of countries within the range of the species, followed by body mass and years since the taxonomic description. Research volume (more than one document) was strongly associated with number of years since the data describing on that species, followed by scientific capacity within the range of species, high body mass and invasiveness. The threat status was weakly associated to explain the presence/absence and research volume in conservation research. These results can be interpreted as a consequence of the dynamic interplay between the perceived need for conservation research about a species and its appropriateness as a target of research. As anticipated, the scientific capacity of the countries where a species is found is a strong driver of conservation research bias, reflecting the high variation in conservation research funding and human resources between countries. Our study suggests that this bias could be most effectively reduced by a combination of investing in pioneering research, targeted funding and supporting research in countries with low scientific capacity and high biodiversity.Peer reviewe

Is extinction forever?

We thank the various people who provided feedback and encouragement when we presented preliminary findings at the June 2012 annual conference of the Association for Tropical Biology and Conservation in Bonito, Brazil. We also thank Richard J. Ladle and an anonymous reviewer for direct comments to the manuscript.Mistrust of science has seeped into public perception of the most fundamental aspect of conservation—extinction. The term ought to be straightforward, and yet, there is a disconnect between scientific discussion and public views. This is not a mere semantic issue, rather one of communication. Within a population dynamics context, we say that a species went locally extinct, later to document its return. Conveying our findings matters, for when we use local extinction, an essentially nonsensical phrase, rather than extirpation, which is what is meant, then we contribute to, if not create outright, a problem for public understanding of conservation, particularly as local extinction is often shortened to extinction in media sources. The public that receives the message of our research void of context and modifiers comes away with the idea that extinction is not forever or, worse for conservation as a whole, that an extinction crisis has been invented.Yeshttp://pus.sagepub.com/content/21/3/258.shor

The Anti-Inflammatory Agent Bindarit Attenuates the Impairment of Neural Development through Suppression of Microglial Activation in a Neonatal Hydrocephalus Mouse Model

Neonatal hydrocephalus presents with various degrees of neuroinflammation and long-term neurologic deficits in surgically treated patients, provoking a need for additional medical treatment. We previously reported elevated neuroinflammation and severe periventricular white matter damage in the progressive hydrocephalus (prh) mutant which contains a point mutation in the Ccdc39 gene, causing loss of cilia-mediated unidirectional CSF flow. In this study, we identified cortical neuropil maturation defects such as impaired excitatory synapse maturation and loss of homeostatic microglia, and swimming locomotor defects in early postnatal prh mutant mice. Strikingly, systemic application of the anti-inflammatory small molecule bindarit significantly supports healthy postnatal cerebral cortical development in the prh mutant. While bindarit only mildly reduced the ventricular volume, it significantly improved the edematous appearance and myelination of the corpus callosum. Moreover, the treatment attenuated thinning in cortical Layers II–IV, excitatory synapse formation, and interneuron morphogenesis, by supporting the ramified-shaped homeostatic microglia from excessive cell death. Also, the therapeutic effect led to the alleviation of a spastic locomotor phenotype of the mutant. We found that microglia, but not peripheral monocytes, contribute to amoeboid-shaped activated myeloid cells in prh mutants’ corpus callosum and the proinflammatory cytokines expression. Bindarit blocks nuclear factor (NF)-kB activation and its downstream proinflammatory cytokines, including monocyte chemoattractant protein-1, in the prh mutant. Collectively, we revealed that amelioration of neuroinflammation is crucial for white matter and neuronal maturation in neonatal hydrocephalus. Future studies of bindarit treatment combined with CSF diversion surgery may provide long-term benefits supporting neuronal development in neonatal hydrocephalus.

Public awareness and engagement in relation to the coastal oil spill in northeast Brazil

Social media data is a rich source of information to assess human activities in catastrophic events. Here, we use social media data to understand how the 2019 Brazilian oil spill influenced social attitudes. Data were collected from the globally popular Instagram platform between August 1, 2019 and March 1, 2020. First, we manually identified the 5 most popular (portuguese language) hashtags related to the oil spill #oleonononordeste;#desastreambiental;#ma rsemoleo;#sosnordeste;#ma rsempetroleo. In the sequence, we collected information on captions, post metadata and users associated with posts retrieved using the selected hashtags. We identified a total of 7,413 posts. These posts were grouped in topics: government (47.76%), protest (24.37%), volunteers (24.45%), biodiversity (0.003%), origin (0.006%), tourism (0.008%) and others (0.016%). All topics had the peak of posts in October and November 2019. Nevertheless, interest in the oil spill was temporary, with most posts appearing in the 2-4 months after the beginning of the disaster. Our findings illustrate the enormous potential of using social media data for understanding and monitoring human engagement with environmental disasters, but also suggest that conservationists and environmental groups may only have a limited 'window of opportunity' to engage and mobilize public support for remediation and restoration efforts.Peer reviewe