6,872 research outputs found

    The impact of college student immersion service learning trips on coping with stress and vocational identity

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    This study examined the impact of service learning immersion trips on vocational identity and coping with stress among college students. Fifty-one students (15 males, 36 females) who participated in immersion trips and 76 students (25 males, 51 females) in a non-immersion control group completed a series of questionnaires directly before and immediately after both fall and spring break immersion trips, and during a four-month follow up. Results suggest that, after returning from an immersion trip, students report a greater ability to cope with stress and a somewhat stronger sense of vocational identity relative to students who do not participate in immersion trips

    Nonlocal feedback in ferromagnetic resonance

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    Ferromagnetic resonance in thin films is analyzed under the influence of spatiotemporal feedback effects. The equation of motion for the magnetization dynamics is nonlocal in both space and time and includes isotropic, anisotropic and dipolar energy contributions as well as the conserved Gilbert- and the non-conserved Bloch-damping. We derive an analytical expression for the peak-to-peak linewidth. It consists of four separate parts originated by Gilbert damping, Bloch-damping, a mixed Gilbert-Bloch component and a contribution arising from retardation. In an intermediate frequency regime the results are comparable with the commonly used Landau-Lifshitz-Gilbert theory combined with two-magnon processes. Retardation effects together with Gilbert damping lead to a linewidth the frequency dependence of which becomes strongly nonlinear. The relevance and the applicability of our approach to ferromagnetic resonance experiments is discussed.Comment: 22 pages, 9 figure

    Deeper, Wider, Sharper: Next-Generation Ground-Based Gravitational-Wave Observations of Binary Black Holes

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    Next-generation observations will revolutionize our understanding of binary black holes and will detect new sources, such as intermediate-mass black holes. Primary science goals include: Discover binary black holes throughout the observable Universe; Reveal the fundamental properties of black holes; Uncover the seeds of supermassive black holes.Comment: 14 pages, 3 figures, White Paper Submitted to Astro2020 (2020 Astronomy and Astrophysics Decadal Survey) by GWIC 3G Science Case Team (GWIC: Gravitational Wave International Committee

    Glycosylated proteins preserved over millennia: N-glycan analysis of Tyrolean Iceman, Scythian Princess and Warrior.

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    An improved understanding of glycosylation will provide new insights into many biological processes. In the analysis of oligosaccharides from biological samples, a strict regime is typically followed to ensure sample integrity. However, the fate of glycans that have been exposed to environmental conditions over millennia has not yet been investigated. This is also true for understanding the evolution of the glycosylation machinery in humans as well as in any other biological systems. In this study, we examined the glycosylation of tissue samples derived from four mummies which have been naturally preserved: - the 5,300 year old "Iceman called Oetzi", found in the Tyrolean Alps; the 2,400 year old "Scythian warrior" and "Scythian Princess", found in the Altai Mountains; and a 4 year old apartment mummy, found in Vienna/Austria. The number of N-glycans that were identified varied both with the age and the preservation status of the mummies. More glycan structures were discovered in the contemporary sample, as expected, however it is significant that glycan still exists in the ancient tissue samples. This discovery clearly shows that glycans persist for thousands of years, and these samples provide a vital insight into ancient glycosylation, offering us a window into the distant past

    Potential Environmental Impacts of Hydrogen-based Transportation and Power Systems

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    Hydrogen (H2) offers advantages as an energy carrier: minimal discharge of pollutants, production from multiple sources, increased thermodynamic efficiencies compared to fossil fuels, and reduced dependence on foreign oil. However, potential impacts from the H2 generation processes, transport and distribution of H2, and releases of H2 into the atmosphere have been proposed. The goal of this project was to analyze the effects of emissions of hydrogen, the six criteria pollutants and greenhouse gases on climate, human health, materials and structures. This project was part of a larger effort by DOE to assess the life-cycle costs and benefits and environmental impacts to inform decisions regarding future hydrogen research. Technical Approach: A modeling approach was developed and used to evaluate the potential environmental effects associated with the conversion of the on-road vehicle fleet from fossil-fuel vehicles to hydrogen fuel cell vehicles. GATOR-GCMOM was the primary tool used to predict atmospheric concentrations of gases and aerosols for selected scenarios. This model accounts for all feedbacks among major atmospheric processes based on first principles. The future scenarios and the emission rates selected for this analysis of hydrogen environmental effects are based on the scenarios developed by IPCC. The scenarios selected for the model simulations are a 2000 and 2050 A1B base cases, and a 2050 A1B case with hydrogen fuel cell vehicles (HFCVs). The hydrogen fuel cell scenario assumed conversion of 90% of fossil-fuel on-road vehicles (FFOV) in developed countries and 45% of FFOVs vehicles in other countries to HFCVs, with the H2 produced by steam-reforming of natural gas (SHFCVs). Simulations were conducted to examine the effect of converting the worldâÂÂs FFOVs to HFCVs, where the H2 is produced by wind-powered electrolysis (WHFCVs). In all scenarios a 3% leakage of H2 consumed was assumed. Two new models were developed that provide the ability to evaluate a wider range of conditions and address some of the uncertainties that exist in the evaluation of hydrogen emissions. A simplified global hydrogen cycle model that simulates hydrogen dynamics in the troposphere and stratosphere was developed. A Monte Carlo framework was developed to address hydrogen uptake variability for different types of ecosystems. Findings 1.Converting vehicles worldwide in 2050 to SHFCVs at 90% penetration in developed countries and 45% penetration in other countries is expected to reduce NOx, CO, CO2, CH4, some other organic gases, ozone, PAN, black carbon, and other particle components in the troposphere, but may increase some other organic gases, depending on emissions. Conversion to SHFCVs is also expected to cool the troposphere and warm the stratosphere, but to a lesser extent than WHFCVs. Finally, SHFCVs are expected to increase UTLS ozone while decreasing upper stratospheric ozone, but to a lesser extent than WHFCVs. 2.The predicted criteria pollutant concentrations from the GATOR-GCMOM simulations indicated that near-surface annual mean concentrations in the US are likely to increase from the 2000 base case to the 2050 A1B base case for CO2 and ozone due to the increased economic activity, but to decrease for CO, NO2, SO2, and PM10 due to improved pollution control equipment and energy efficiencies. The shift to SHFCVs in 2050 was predicted to result in decreased concentrations for all the criteria pollutants, except for SO2 and PM10. The higher predicted concentrations for SO2 and PM10 were attributed to increased emissions using the steam-reforming method to generate H2. If renewable methods such as wind-based electrolysis were used to generate H2, the emissions of SO2 and PM10 would be lower. 3.The effects on air quality, human health, ecosystem, and building structures were quantified by comparing the GATOR-GCMOM model output and accepted health and ecosystem effects levels and ambient air quality criteria. Shifting to HFCVs is expected to result in improved air quality and benefits to human health. Shifting to HFCVs is unlikely to result in damage to buildings. 4.Results are thought to be robust for larger leakage rates of H2 and for greater penetrations of HFCVs, since the controlling factor for stratospheric ozone impacts is the reduction in fossil-fuel greenhouse gases and the resulting surface cooling, which reduces water vapor emissions and stratospheric warming, which increases tropopause stability reducing water vapor transport to the stratosphere. 5.The supplemental modeling results were generally supportive of the results from the GATOR-GCMOM simulations, and recommendations for additional analyses were made. Extending the duration of the simulation to coincide with the time required for hydrogen mixing ratios to attain a steady state condition was recommended. Further evaluation of algorithms to describe hydrogen uptake in the model was also recommended

    Maximising the impact of qualitative research in feasibility studies for randomised controlled trials: guidance for researchers

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    Feasibility studies are increasingly undertaken in preparation for randomised controlled trials in order to explore uncertainties and enable trialists to optimise the intervention or the conduct of the trial. Qualitative research can be used to examine and address key uncertainties prior to a full trial. We present guidance that researchers, research funders and reviewers may wish to consider when assessing or undertaking qualitative research within feasibility studies for randomised controlled trials. The guidance consists of 16 items within five domains: research questions, data collection, analysis, teamwork and reporting. Appropriate and well conducted qualitative research can make an important contribution to feasibility studies for randomised controlled trials. This guidance may help researchers to consider the full range of contributions that qualitative research can make in relation to their particular trial. The guidance may also help researchers and others to reflect on the utility of such qualitative research in practice, so that trial teams can decide when and how best to use these approaches in future studies

    Routine delivery of artemisinin-based combination treatment at fixed health facilities reduces malaria prevalence in Tanzania: an observational study

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    BACKGROUND Artemisinin-based combination therapy (ACT) has been promoted as a means to reduce malaria transmission due to their ability to kill both asexual blood stages of malaria parasites, which sustain infections over long periods and the immature derived sexual stages responsible for infecting mosquitoes and onward transmission. Early studies reported a temporal association between ACT introduction and reduced malaria transmission in a number of ecological settings. However, these reports have come from areas with low to moderate malaria transmission, been confounded by the presence of other interventions or environmental changes that may have reduced malaria transmission, and have not included a comparison group without ACT. This report presents results from the first large-scale observational study to assess the impact of case management with ACT on population-level measures of malaria endemicity in an area with intense transmission where the benefits of effective infection clearance might be compromised by frequent and repeated re-infection. METHODS A pre-post observational study with a non-randomized comparison group was conducted at two sites in Tanzania. Both sites used sulphadoxine-pyrimethamine (SP) monotherapy as a first-line anti-malarial from mid-2001 through 2002. In 2003, the ACT, artesunate (AS) co-administered with SP (AS + SP), was introduced in all fixed health facilities in the intervention site, including both public and registered non-governmental facilities. Population-level prevalence of Plasmodium falciparum asexual parasitaemia and gametocytaemia were assessed using light microscopy from samples collected during representative household surveys in 2001, 2002, 2004, 2005 and 2006. FINDINGS Among 37,309 observations included in the analysis, annual asexual parasitaemia prevalence in persons of all ages ranged from 11% to 28% and gametocytaemia prevalence ranged from <1% to 2% between the two sites and across the five survey years. A multivariable logistic regression model was fitted to adjust for age, socioeconomic status, bed net use and rainfall. In the presence of consistently high coverage and efficacy of SP monotherapy and AS + SP in the comparison and intervention areas, the introduction of ACT in the intervention site was associated with a modest reduction in the adjusted asexual parasitaemia prevalence of 5 percentage-points or 23% (p < 0.0001) relative to the comparison site. Gametocytaemia prevalence did not differ significantly (p = 0.30). INTERPRETATION The introduction of ACT at fixed health facilities only modestly reduced asexual parasitaemia prevalence. ACT is effective for treatment of uncomplicated malaria and should have substantial public health impact on morbidity and mortality, but is unlikely to reduce malaria transmission substantially in much of sub-Saharan Africa where individuals are rapidly re-infected.Financial support for IMPACT-Tz came primarily from CDC, the U.S. Agency for International Development and the Wellcome Trust

    The Vehicle, February 1960, Vol. 2 no. 1

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    Vol. 2, No. 1 Table of Contents Editorialpage 2 A White Man\u27s BurdenRobert Mills Frenchpage 4 Passing TrainWayne Bakerpage 8 AutumnMajor Dan Ragainpage 8 Chaos in CulturevilleJ.B. Youngpage 9 Cure-allJerry N. Whitepage 13 Love-Long DistanceMary Ellen Mockbeepage 13 Metropolitan CaravanThomas McPeakpage 14 Ode to the Lion HuntersRichard Blairpage 16 ImmortalityM.E.M.page 16 EntranceSam Martinpage 16https://thekeep.eiu.edu/vehicle/1006/thumbnail.jp
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