238 research outputs found

    A new golden era in island biogeography

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    For two centuries, islands have served as rich sources of inspiration and data for biogeogra-phers, thus gaining renown as ideal natural laboratories. Their research potential continues to expand today thanks to the combined application of recent advances in several scientific fields. First, increas-ingly detailed geological and palaeoecological data are extending our understanding of the history of development of island biotas. At the same time, rapid methodological advances in molecular evolution-ary biology and systematics are revealing the pathways by which species colonized islands, evolved, and formed communities. Third, basic data on species distributions are being collected from increasing num-bers of islands and taxa, distributed widely through electronic resources, and analyzed with powerful software to reveal macroecological patterns. The pace and quality of recent advances signal a promising future in which islands will continue to play key roles in revealing how biodiversity is produced and maintained

    In search of community history

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    This editorial response to the preceding article by Dennis Mills addresses the meaning of community history. Rejecting an over-tight definition, we argue for a methodologically distinct community history, combining a micro-historical approach with a sensitivity to the discursive construction of the term 'community'. Furthermore the role of family and community historians should be to adapt a critical stance towards contemporary meanings of both past 'communities' and past 'families'. The article concludes that Withington and Shephard's schema for approaching the history of 'community' offers a practical way forward for the family and community historian

    Immunomodulation and T Helper TH1/TH2 Response Polarization by CeO2 and TiO2 Nanoparticles

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    Immunomodulation by nanoparticles, especially as related to the biochemical properties of these unique materials, has scarcely been explored. In an in vitro model of human immunity, we demonstrate two catalytic nanoparticles, TiO2 (oxidant) and CeO2 (antioxidant), have nearly opposite effects on human dendritic cells and T helper (T-H) cells. For example, whereas TiO2 nanoparticles potentiated DC maturation that led towards T(H)1-biased responses, treatment with antioxidant CeO2 nanoparticles induced APCs to secrete the anti-inflammatory cytokine, IL-10, and induce a T(H)2-dominated T cell profile. In subsequent studies, we demonstrate these results are likely explained by the disparate capacities of the nanoparticles to modulate ROS, since TiO2, but not CeO2 NPs, induced inflammatory responses through an ROS/inflammasome/IL-1 beta pathway. This novel capacity of metallic NPs to regulate innate and adaptive immunity in profoundly different directions via their ability to modulate dendritic cell function has strong implications for human health since unintentional exposure to these materials is common in modern societies

    The influence of the atmospheric boundary layer on nocturnal layers of noctuids and other moths migrating over southern Britain

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    Insects migrating at high altitude over southern Britain have been continuously monitored by automatically-operating, vertical-looking radars over a period of several years. During some occasions in the summer months, the migrants were observed to form well-defined layer concentrations, typically at heights of 200-400 m, in the stable night-time atmosphere. Under these conditions, insects are likely to have control over their vertical movements and are selecting flight heights which are favourable for long-range migration. We therefore investigated the factors influencing the formation of these insect layers by comparing radar measurements of the vertical distribution of insect density with meteorological profiles generated by the UK Met. Office’s Unified Model (UM). Radar-derived measurements of mass and displacement speed, along with data from Rothamsted Insect Survey light traps provided information on the identity of the migrants. We present here three case studies where noctuid and pyralid moths contributed substantially to the observed layers. The major meteorological factors influencing the layer concentrations appeared to be: (a) the altitude of the warmest air, (b) heights corresponding to temperature preferences or thresholds for sustained migration and (c), on nights when air temperatures are relatively high, wind-speed maxima associated with the nocturnal jet. Back-trajectories indicated that layer duration may have been determined by the distance to the coast. Overall, the unique combination of meteorological data from the UM and insect data from entomological radar described here show considerable promise for systematic studies of high-altitude insect layering

    Immunomodulation and T Helper TH1/TH2 Response Polarization by CeO2 and TiO2 Nanoparticles

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    Immunomodulation by nanoparticles, especially as related to the biochemical properties of these unique materials, has scarcely been explored. In an in vitro model of human immunity, we demonstrate two catalytic nanoparticles, TiO2 (oxidant) and CeO2 (antioxidant), have nearly opposite effects on human dendritic cells and T helper (T-H) cells. For example, whereas TiO2 nanoparticles potentiated DC maturation that led towards T(H)1-biased responses, treatment with antioxidant CeO2 nanoparticles induced APCs to secrete the anti-inflammatory cytokine, IL-10, and induce a T(H)2-dominated T cell profile. In subsequent studies, we demonstrate these results are likely explained by the disparate capacities of the nanoparticles to modulate ROS, since TiO2, but not CeO2 NPs, induced inflammatory responses through an ROS/inflammasome/IL-1 beta pathway. This novel capacity of metallic NPs to regulate innate and adaptive immunity in profoundly different directions via their ability to modulate dendritic cell function has strong implications for human health since unintentional exposure to these materials is common in modern societies

    Coupling sensitive \u3cem\u3ein vitro\u3c/em\u3e and in silico techniques to assess cross-reactive CD4\u3csup\u3e+\u3c/sup\u3e T cells against the swine-origin H1N1 influenza virus

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    The outbreak of the novel swine-origin H1N1 influenza in the spring of 2009 took epidemiologists, immunologists, and vaccinologists by surprise and galvanized a massive worldwide effort to produce millions of vaccine doses to protect against this single virus strain. Of particular concern was the apparent lack of pre-existing antibody capable of eliciting cross-protective immunity against this novel virus, which fueled fears this strain would trigger a particularly far-reaching and lethal pandemic. Given that disease caused by the swine-origin virus was far less severe than expected, we hypothesized cellular immunity to cross-conserved T cell epitopes might have played a significant role in protecting against the pandemic H1N1 in the absence of cross-reactive humoral immunity. In a published study, we used an immunoinformatics approach to predict a number of CD4+ T cell epitopes are conserved between the 2008–2009 seasonal H1N1 vaccine strain and pandemic H1N1 (A/California/04/2009) hemagglutinin proteins. Here, we provide results from biological studies using PBMCs from human donors not exposed to the pandemic virus to demonstrate that pre-existing CD4+ T cells can elicit cross-reactive effector responses against the pandemic H1N1 virus. As well, we show our computational tools were 80–90% accurate in predicting CD4+ T cell epitopes and their HLA-DRB1-dependent response profiles in donors that were chosen at random for HLA haplotype. Combined, these results confirm the power of coupling immunoinformatics to define broadly reactive CD4+ T cell epitopes with highly sensitive in vitro biological assays to verify these in silico predictions as a means to understand human cellular immunity, including cross-protective responses, and to define CD4+ T cell epitopes for potential vaccination efforts against future influenza viruses and other pathogens

    Intermediate- and High-Velocity Ionized Gas toward zeta Orionis

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    We combine UV spectra obtained with the HST/GHRS echelle, IMAPS, and Copernicus to study the abundances and physical conditions in the predominantly ionized gas seen at high (-105 to -65 km/s) and intermediate velocities (-60 to -10 km/s) toward zeta Ori. We have high resolution (FWHM ~ 3.3-4.5 km/s) and/or high S/N spectra for at least two significant ions of C, N, Al, Si, S, and Fe -- enabling accurate estimates for both the total N(H II) and the elemental depletions. C, N, and S have essentially solar relative abundances; Al, Si, and Fe appear to be depleted by about 0.8, 0.3-0.4, and 0.95 dex, respectively. While various ion ratios would be consistent with collisional ionization equilibrium (CIE) for T ~ 25,000-80,000 K, the widths of individual high-velocity absorption components indicate that T ~ 9000 K -- so the gas is not in CIE. Analysis of the C II fine-structure excitation equilibrium yields estimated densities (n_e ~ n_H ~ 0.1-0.2 cm^{-3}), thermal pressures (2 n_H T ~ 2000-4000 cm^{-3}K), and thicknesses (0.5-2.7 pc) for the individual clouds. We compare the abundances and physical properties derived for these clouds with those found for gas at similar velocities toward 23 Ori and tau CMa, and also with several models for shocked gas. While the shock models can reproduce some features of the observed line profiles and some of the observed ion ratios, there are also significant differences. The measured depletions suggest that \~10% of the Al, Si, and Fe originally locked in dust in the pre-shock medium may have been returned to the gas phase, consistent with predictions for the destruction of silicate dust in a 100 km/s shock. The near-solar gas phase abundance of carbon, however, seems inconsistent with the predicted longer time scales for the destruction of graphite grains.Comment: 50 pages, 9 figures; aastex; accepted by Ap
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