303 research outputs found

    The effects of climate variability on the timing of ichthyoplankton ingress through Beaufort Inlet, NC, USA

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    Climate change has shifted the timing of seasons in many ecosystems worldwide. Species are responding to these shifting seasons with shifts of their own, both in space via migrations and in time via phenology. However, species vary in the direction and magnitude of these spatial and temporal shifts. As the effects of climate change become more pronounced, this variation in the response of species may disrupt interspecific interactions in ecological communities. Research into the responses of species to climate change is therefore critical to understanding how ecosystems may function in the future. In this thesis I examined one way in which the fall and winter ichthyoplankton community of Beaufort Inlet, North Carolina has responded to environmental variability over the last 27 years. I related changes in sea surface temperature, the Atlantic Multidecadal Oscillation, the North Atlantic Oscillation, offshore wind phenology, nearshore wind strength, and tidal height to the time at which ten species of larval fish ingressed through Beaufort Inlet. I also examined whether any species had exhibited trends in ingress phenology over the last three decades. Species varied in the magnitude of their responses to all of the environmental variables studied, but most shared a common direction of change. Sea surface temperature and northerly wind strength appear to have the largest impact on ingress phenology, with most species advancing their ingress during warm years and delaying ingress during years of strong northerly winds. As sea surface temperatures warm in the coming decades, the average timing of ingress of some species may advance on the order of weeks to months, assuming temperatures do not exceed a threshold at which species can no longer respond. These shifts in ingress could affect the chances of survival of larvae since environmental conditions in the estuarine and pelagic nursery habitats of fishes also vary seasonally. The extent to which larval survival is affected by their changes in phenology will depend on how climate change shapes conditions in estuarine and coastal habitats

    Directions for 21st Century Lifelong Learning Institutes: Elucidating Questions from Osher Lifelong Learning Institute Studies

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    The literature regarding lifelong learning is robust, while the literature on lifelong learning institutions, centers, and programs remain under-researched in comparison. This article draws insights from a specific network of lifelong learning institutes with a rich history and high rapport in the United States: the Osher Lifelong Learning Institute (OLLI) network. Sixty articles regarding OLLIs are catalogued and highlighted to elucidate twelve thematic areas and twelve questions for future research and practice. In particular, these themes are related to adult education, healthy aging, and educational gerontology. The article concludes by reflecting on trends in and needs for institutional research and practice.Les publications portant sur l’éducation permanente sont nombreuses, contrairement à celles touchant les institutions, centres et programmes d’éducation permanente qui, en comparaison, demeurent généralement mal connus. Cet article recueille des idées d’un réseau d’instituts d’éducation permanente ayant un passé riche et de bons rapports aux États-Unis : le réseau Osher Lifelong Learning Institute (OLLI). Soixante articles portant sur OLLI ont été catalogués et analysés pour faire ressortir douze thèmes et douze questions pour la recherche et la pratique à l’avenir. Ces thèmes se rattachent à l’éducation des adultes, le vieillissement sain et la gérontologie éducative. L’article se termine par des réflexions sur des tendances et des besoins relatifs à la recherche et la pratique institutionnelles.Mots clés : recherche institutionnelle, éducation permanente, ainés, éducation des adultes, universités adaptées aux personnes âgée

    Blood\u27s Concentration of Lead and Arsenic Associated with Anemia in Peruvian Children

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    This exploratory, descriptive cohort study (N = 60) determined lead (Pb) and arsenic (As) blood concentrations in Peruvian children and their association with hematological parameters of iron-deficient anemia (IDA) and anthropometric measurement. The mean age of children was 10.8 months (SD = 4.7) and ranged from 3 to 24 months old. Anemia (Hb levels below 10.5 g/dL) was found in 20% of this cohort. Additionally, microcytosis (MCV \u3c 70 fL) was present in 54%, and hypochromia (MCH \u3c 23 pg) in 42% of the group of children. Chi-square analysis showed that 88% of the children with anemia also had microcytosis and hypochromia (p \u3c 0.001). Pb and As were detected in 100% of the infants’ blood samples, and the concentrations were significantly higher in older infants than in younger ones. Pb and As were not associated with the sex, anthropomorphic parameters, or infant hemogram changes. Infants who received iron supplementation were 87% less likely to have low Hb compared with those who did not (OR = 0.13, 95% CI = 0.02–0.88, p = 0.04). Herbal tea intake was significantly associated with microcytosis and hypochromia. Our finding uncovered that hematological parameters for anemia are modified in Peruvian children with high levels of microcytosis and hypochromia. Concentrations of Pb and As were above method detection limits in all Peruvian children, but these were not associated with IDA or anthropometric measurements. A large study, including other variables, would benefit from allowing a more complex model predicting anemia in Peruvian children

    Rate Constant for the NH 3 ؉ NO 2 : NH 2 ؉ HONO Reaction: Comparison of Kinetically Modeled and Predicted Results

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    ABSTRACT: The rate constant for the NH 3 Ď© NO 2 L NH 2 Ď© HONO reaction (1) has been kinetically modeled by using the photometrically measured NO 2 decay rates available in the literature. The rates of NO 2 decay were found to be strongly dependent on reaction (1) and, to a significant extent, on the secondary reactions of NH 2 with NO x and the decomposition of HONO formed in the initiation reaction. These secondary reactions lower the values of k 1 determined directly from the experiments. Kinetic modeling of the initial rates of NO 2 decay computed from the reported rate equation

    Decreased Axon Caliber Underlies Loss of Fiber Tract Integrity, Disproportional Reductions in White Matter Volume, and Microcephaly in Angelman Syndrome Model Mice

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    Angelman syndrome (AS) is a debilitating neurodevelopmental disorder caused by loss of function of the maternally inherited UBE3A allele. It is currently unclear how the consequences of this genetic insult unfold to impair neurodevelopment. We reasoned that by elucidating the basis of microcephaly in AS, a highly penetrant syndromic feature with early postnatal onset, we would gain new insights into the mechanisms by which maternal UBE3A loss derails neurotypical brain growth and function. Detailed anatomical analysis of both male and female maternal Ube3a-null mice reveals that microcephaly in the AS mouse model is primarily driven by deficits in the growth of white matter tracts, which by adulthood are characterized by densely packed axons of disproportionately small caliber. Our results implicate impaired axon growth in the pathogenesis of AS and identify noninvasive structural neuroimaging as a potentially valuable tool for gauging therapeutic efficacy in the disorder

    Maternal neurofascin-specific autoantibodies bind to structures of the fetal nervous system during pregnancy, but have no long term effect on development in the rat

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    Neurofascin was recently reported as a target for axopathic autoantibodies in patients with multiple sclerosis (MS), a response that will exacerbate axonal pathology and disease severity in an animal model of multiple sclerosis. As transplacental transfer of maternal autoantibodies can permanently damage the developing nervous system we investigated whether intrauterine exposure to this neurofascin-specific response had any detrimental effect on white matter tract development. To address this question we intravenously injected pregnant rats with either a pathogenic anti-neurofascin monoclonal antibody or an appropriate isotype control on days 15 and 18 of pregnancy, respectively, to mimic the physiological concentration of maternal antibodies in the circulation of the fetus towards the end of pregnancy. Pups were monitored daily with respect to litter size, birth weight, growth and motor development. Histological studies were performed on E20 embryos and pups sacrificed on days 2, 10, 21, 32 and 45 days post partum. Results: Immunohistochemistry for light and confocal microscopy confirmed passively transferred anti-neurofascin antibody had crossed the placenta to bind to distinct structures in the developing cortex and cerebellum. However, this did not result in any significant differences in litter size, birth weight, or general physical development between litters from control mothers or those treated with the neurofascin-specific antibody. Histological analysis also failed to identify any neuronal or white matter tract abnormalities induced by the neurofascin-specific antibody. Conclusions: We show that transplacental transfer of circulating anti-neurofascin antibodies can occur and targets specific structures in the CNS of the developing fetus. However, this did not result in any pre- or post-natal abnormalities in the offspring of the treated mothers. These results assure that even if anti-neurofascin responses are detected in pregnant women with multiple sclerosis these are unlikely to have a negative effect on their children

    In Vivo Deletion of Immunoglobulin Domains 5 and 6 in Neurofascin (Nfasc) Reveals Domain-Specific Requirements in Myelinated Axons

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    The formation of paranodal axo-glial junctions is critical for the rapid and efficient propagation of nerve impulses. Genetic ablation of genes encoding the critical paranodal proteins Caspr, contactin (Cont), and the myelinating glia-specific isoform of Neurofascin (NfascNF155) results in the disruption of the paranodal axo-glial junctions, loss of ion channel segregation, and impaired nerve conduction, but the mechanisms regulating their interactions remains elusive. Here, we report that loss of immunoglobulin (Ig) domains 5 and 6 in NfascNF155 in mice phenocopies complete ablation of NfascNF155. The mutant mice lack paranodal septate junctions, resulting in the diffusion of Caspr and Cont from the paranodes, and redistribution of the juxtaparanodal potassium channels towards the nodes. While critical for NfascNF155 function, we find that Ig5-6 are dispensable for nodal NfascNF186 function. Moreover, in vitro binding assays using Ig5-6 deletion constructs reveal their importance for the association of NfascNF155 with Cont. These findings provide the first molecular evidence demonstrating domain specific requirements controlling the association of the paranodal tripartite complex in vivo. Our studies further emphasize that in vivo structure/function analysis is necessary to define the unique protein/protein interactions that differentially regulate the functions of Neurofascins during axonal domain organization

    PEG Branched Polymer for Functionalization of Nanomaterials with Ultralong Blood Circulation

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    Nanomaterials have been actively pursued for biological and medical applications in recent years. Here, we report the synthesis of several new poly(ethylene glycol) grafted branched-polymers for functionalization of various nanomaterials including carbon nanotubes, gold nanoparticles (NP) and gold nanorods (NRs), affording high aqueous solubility and stability for these materials. We synthesize different surfactant polymers based upon poly-(g-glutamic acid) (gPGA) and poly(maleic anhydride-alt-1-octadecene) (PMHC18). We use the abundant free carboxylic acid groups of gPGA for attaching lipophilic species such as pyrene or phospholipid, which bind to nanomaterials via robust physisorption. Additionally, the remaining carboxylic acids on gPGA or the amine-reactive anhydrides of PMHC18 are then PEGylated, providing extended hydrophilic groups, affording polymeric amphiphiles. We show that single-walled carbon nanotubes (SWNTs), Au NPs and NRs functionalized by the polymers exhibit high stability in aqueous solutions at different pHs, at elevated temperatures and in serum. Morever, the polymer-coated SWNTs exhibit remarkably long blood circulation (t1/2 22.1 h) upon intravenous injection into mice, far exceeding the previous record of 5.4 h. The ultra-long blood circulation time suggests greatly delayed clearance of nanomaterials by the reticuloendothelial system (RES) of mice, a highly desired property for in vivo applications of nanomaterials, including imaging and drug delivery
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