646 research outputs found

    The Assassin Bug \u3ci\u3eZelus Luridus\u3c/i\u3e (Heteroptera: Reduviidae) in Michigan\u27s Upper Peninsula

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    (excerpt) On 17 July 1992, an assassin bug (Zelus luridus Stal) was flushed from the stomach of a smallmouth bass (Micropterus dolomieu) collected in West Long Lake of the University of Notre Dame Environmental Research Center, Gogebic County, Michigan

    Learning From Early Attempts to Generalize Darwinian Principles to Social Evolution

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    Copyright University of Hertfordshire & author.Evolutionary psychology places the human psyche in the context of evolution, and addresses the Darwinian processes involved, particularly at the level of genetic evolution. A logically separate and potentially complementary argument is to consider the application of Darwinian principles not only to genes but also to social entities and processes. This idea of extending Darwinian principles was suggested by Darwin himself. Attempts to do this appeared as early as the 1870s and proliferated until the early twentieth century. But such ideas remained dormant in the social sciences from the 1920s until after the Second World War. Some lessons can be learned from this earlier period, particularly concerning the problem of specifying the social units of selection or replication

    Trophic Cascades, Nutrients, and Lake Productivity: Whole-Lake Experiments

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    Responses of zooplankton, pelagic primary producers, planktonic bacteria, and CO2 exchange with the atmosphere were measured in four lakes with contrasting food webs under a range of nutrient enrichments during a seven-year period. Prior to enrichment, food webs were manipulated to create contrasts between piscivore dominance and planktivore dominance. Nutrient enrichments of inorganic nitrogen and phosphorus exhibited ratios of N:P \u3e 17:1, by atoms, to maintain P limitation. An unmanipulated reference lake, Paul Lake, revealed baseline variability but showed no trends that could confound the interpretation of changes in the nearby manipulated lakes. Herbivorous zooplankton of West Long Lake (piscivorous fishes) were large-bodied Daphnia spp., in contrast to the small-bodied grazers that predominated in Peter Lake (planktivorous fishes). At comparable levels of nutrient enrichment, Peter Lake\u27s areal chlorophyll and areal primary production rates exceeded those of West Long Lake by factors of approximately three and six, respectively. Grazers suppressed pelagic primary producers in West Long Lake, relative to Peter Lake, even when nutrient input rates were so high that soluble reactive phosphorus accumulated in the epilimnions of both lakes during summer. Peter Lake also had higher bacterial production (but not biomass) than West Long Lake. Hydrologic changes that accompanied manipulation of East Long Lake caused concentrations of colored dissolved organic carbon to increase, leading to considerable variability in fish and zooplankton populations. Both trophic cascades and water color appeared to inhibit the response of primary producers to nutrients in East Long Lake. Carbon dioxide was discharged to the atmosphere by Paul Lake in all years and by the other lakes prior to nutrient addition. During nutrient addition, only Peter Lake consistently absorbed CO2 from the atmosphere, due to high rates of carbon fixation by primary producers. In contrast, CO2 concentrations of West Long Lake shifted to near-atmospheric levels, and net fluxes were near zero, while East Long Lake continued to discharge CO2 to the atmosphere

    Experimental and Theoretical Studies of the Redox Potentials of Cyclic Nitroxides

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    (Chemical Equation Presented) The redox potentials of 25 cyclic nitroxides from four different structural classes (pyrrolidine, piperidine, isoindoline, and azaphenalene) were determined experimentally by cyclic voltammetry in acetonitrile, and also via high-level ab initio molecular orbital calculations. It is shown that the potentials are influenced by the type of ring system, ring substituents and/or groups surrounding the radical moiety. For the pyrrolidine, piperidine, and isoindolines there is excellent agreement (mean absolute deviation of 0.05 V) between the calculated and experimental oxidation potentials; for the azaphenalenes, however, there is an extraordinary discrepancy (mean absolute deviation of 0.60 V), implying that their one-electron oxidation might involve additional processes not considered in the theoretical calculations. This recently developed azaphenalene class of nitroxide represents a new variant of a nitroxide ring fused to an aromatic system and details of the synthesis of five derivatives involving differing aryl substitution are also presented

    Preliminary Testing of a Pressurized Space Suit and Candidate Fabrics Under Simulated Mars Dust Storm and Dust Devil Conditions

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    In August 2009 YAP Films (Toronto) received permission from all entities involved to create a documentary film illustrating what it might be like to be on the surface of Mars in a space suit during a dust storm or in a dust devil. The science consultants on this project utilized this opportunity to collect data which could be helpful to assess the durability of current space suit construction to the Martian environment. The NDX?1 prototype planetary space suit developed at the University of North Dakota was used in this study. The suit features a hard upper torso garment, and a soft lower torso and boots assembly. On top of that, a nylon-cotton outer layer is used to protect the suit from dust. Unmanned tests were carried out in the Martian Surface Wind Tunnel (MARSWIT) at the NASA Ames Research Center, with the suit pressurized to 10 kPa gauge. These tests blasted the space suit upper torso and helmet, and a collection of nine candidate outer layer fabrics, with wind-borne simulant for five different 10 minute tests under both terrestrial and Martian surface pressures. The infiltration of the dust through the outer fabric of the space suit was photographically documented. The nine fabric samples were analyzed under light and electron microscopes for abrasion damage. Manned tests were carried out at Showbiz Studios (Van Nuys, CA) with the pressure maintained at 20?2 kPa gauge. A large fan-created vortex lifted Martian dust simulant (Fullers Earth or JSC Mars?1) off of the floor, and one of the authors (Lee) wearing the NDX?1 space suit walked through it to judge both subjectively and objectively how the suit performed under these conditions. Both the procedures to scale the tests to Martian conditions and the results of the infiltration and abrasion studies will be discussed

    Mediation, translation and local ecologies: understanding the impact of policy levers on FE colleges

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    This article reports the views of managers and tutors on the role of policy ‘levers’ on teaching, learning, and inclusion in colleges of Further Education (FE) in our research project, ‘The impact of policy on learning and inclusion in the Learning and Skills Sector (LSS)’.i Using data from five research visits conducted over two years in eight FE learning sites, we explore the processes by which colleges ‘mediate’ and ‘translate’ national policy levers and how this affects their ability to respond to local need. The paper tentatively develops three related concepts/metaphors to explain the complexity of the policy/college interface – ‘the process of mediation’, ‘acts of translation’ and ‘local ecologies’. We found that policy levers interacted with a complex set of national, local and institutional factors as colleges responded to pressures from the external environment and turned these into internal plans, systems and practices. We conclude by suggesting that national policy-makers, who design national policy levers, may not be fully aware of these complexities and we make the case for the benefits of greater local control over policy levers, where these interactions are better understood

    Psychological distress and quality of life in asymptomatic adults following provision of imaging results for prevention of cardiovascular disease events: A scoping review

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    Aims Psychological distress and changes in health-related quality of life (HRQoL) may occur after screening for disease. Reporting outcomes related to potential benefits and harms of screening is a key recommendation in the guidelines for reporting high-quality trials or interventions. However, no reviews have directly investigated outcomes related to psychological distress and/or changes in HRQoL following imaging assessment of cardiovascular risk and communication of cardiovascular findings to asymptomatic adults. A scoping review was conducted to map research on psychological distress and/or HRQoL following screening. Methods and results Six electronic databases (MEDLINE, PsychINFO, Social Work Abstracts, Psychology and Behavioural Sciences Collection, CINAHL, and EMBASE) were searched for articles that assessed psychological distress and/or HRQoL following screening. Two investigators independently screened titles and abstracts for all records retrieved using predefined criteria. Studies were conducted among active smokers, military personnel, athletes, post-menopausal women, and high-risk individuals. Seven constructs related to psychological distress and HRQoL appeared across 11 articles (randomized controlled trials, n = 4 and non-randomized studies, n = 7). Worry, depression, perceived stress, anxiety, and quality of life were most prominent. Multiple-item measures of psychological distress (e.g. Taylor Anxiety Score and Beck Depression Inventory) were used in 5/9 (56%) studies. Key findings on psychological distress and/or changes in HRQoL following screening were mixed. Conclusions Findings support the need for multiple-item measures with better psychometric properties to examine the psychological responses to screening results in future studies. Strategies to support individuals during and following vascular screening to maximise potential benefits of screening and minimize harms are discussed

    Do British birds conform to Bergmann's and Allen's rules? An analysis of body size variation with latitude for four species

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    Capsule: An analysis of body mass and wing length for four bird species shows trends broadly in line with predictions from Bergmann's and Allen's rules but with species- and sex-specific trends in terms of body size variation with latitude in Britain. Aims: To analyse body size characteristics for bird species with latitude in Britain and to test Bergmann’s and Allen’s rules (over a range of c. 740 km). Methods Body mass and wing length for four bird species (Blackbird Turdus merula, House Sparrow Passer domesticus, Robin Erithacus rubecula, and Song Thrush Turdus philomelos) were analysed using principal components regression analysis to investigate trends with latitude, longitude, or by sex and Julian day. Results: Evidence was found for latitudinal gradients in body mass for male Blackbird, female House Sparrow (both increasing in size northwards), and female Robin (decreasing in size northwards) and in wing length for female Robin and male Song Thrush (decreasing and increasing northwards, respectively). Conclusion: Trends were broadly in line with predictions from Bergmann's and Allen's rules except for Robin which had trends opposite to those expected. Differences in trends between sexes suggest a role for an interplay between natural and sexual selection with latitude that deserves further consideration

    Environmentally relevant iron oxide nanoparticles produce limited acute pulmonary effects in rats at realistic exposure levels

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    Iron is typically the dominant metal in the ultrafine fraction of airborne particulate matter. Various studies have investigated the toxicity of inhaled nano-sized iron oxide particles (FeOxNPs) but their results have been contradictory, with some indicating no or minor effects and others finding effects including oxidative stress and inflammation. Most studies, however, did not use materials reflecting the characteristics of FeOxNPs present in the environment. We, therefore, analysed the potential toxicity of FeOxNPs of different forms (Fe3O4 , α-Fe2O3 and Îł-Fe2O3 ) reflecting the characteristics of high iron content nano-sized particles sampled from the environment, both individually and in a mixture (FeOx-mix). A preliminary in vitro study indicated Fe3O4 and FeOx-mix were more cytotoxic than either form of Fe2O3 in human bronchial epithelial cells (BEAS-2B). Follow-up in vitro (0.003, 0.03, 0.3 ”g/mL, 24 h) and in vivo (Sprague–Dawley rats, nose-only exposure, 50 ”g/m3 and 500 ”g/m3 , 3 h/d × 3 d) studies therefore focused on these materials. Experiments in vitro explored responses at the molecular level via multi-omics analyses at concentrations below those at which significant cytotoxicity was evident to avoid detection of responses secondary to toxicity. Inhalation experiments used aerosol concentrations chosen to produce similar levels of particle deposition on the airway surface as were delivered in vitro. These were markedly higher than environmental concentrations. No clinical signs of toxicity were seen nor effects on BALF cell counts or LDH levels. There were also no significant changes in transcriptomic or metabolomic responses in lung or BEAS-2B cells to suggest adverse effects
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