493 research outputs found

    Using chemical, microbial and fluorescence techniques to understand contaminant sources and pathways to wetlands in a conservation site

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    Nutrients and faecal contaminants can enter wetland systems in a number of ways, with both biological and potentially human-health implications. In this study we used a combination of inorganic chemistry, dissolved organic matter (DOM) fluorescence and Escherichia coli and total coliform (TC) count techniques to study the sources and multiple pathways of contamination affecting a designated sand dune site of international conservation importance, surrounded by agricultural land. Analysis of stream samples, groundwater and dune slack wetlands revealed multiple input pathways. These included riverbank seepage, runoff events and percolation of nutrients from adjacent pasture into the groundwater, as well as some on-site sources. The combined techniques showed that off-site nutrient inputs into the sand dune system were primarily from fertilisers, revealed by high nitrate concentrations, and relatively low tryptophan-like fulvic-like ratios < 0.4 Raman units (R.U.). The E. coli and TC counts recorded across the site confirm a relatively minor source of bacterial and nutrient inputs from on-site grazers. Attenuation of the nutrient concentrations in streams, in groundwater and in run-off inputs occurs within the site, restoring healthier groundwater nutrient concentrations showing that contaminant filtration by the sand dunes provides a valuable ecosystem service. However, previous studies show that this input of nutrients has a clear adverse ecological impact

    Relativistic Heavy--Ion Collisions in the Dynamical String--Parton Model

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    We develop and extend the dynamical string parton model. This model, which is based on the salient features of QCD, uses classical Nambu-Got\=o strings with the endpoints identified as partons, an invariant string breaking model of the hadronization process, and interactions described as quark-quark interactions. In this work, the original model is extended to include a phenomenological quantization of the mass of the strings, an analytical technique for treating the incident nucleons as a distribution of string configurations determined by the experimentally measured structure function, the inclusion of the gluonic content of the nucleon through the introduction of purely gluonic strings, and the use of a hard parton-parton interaction taken from perturbative QCD combined with a phenomenological soft interaction. The limited number of parameters in the model are adjusted to e+e−e^+e^- and pp --pp data. Utilizing these parameters, the first calculations of the model for pp --AA and AA--AA collisions are presented and found to be in reasonable agreement with a broad set of data.Comment: 26 pages of text with 23 Postscript figures placed in tex

    Study of Interplanetary Magnetic Field with Ground State Alignment

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    We demonstrate a new way of studying interplanetary magnetic field -- Ground State Alignment (GSA). Instead of sending thousands of space probes, GSA allows magnetic mapping with any ground telescope facilities equipped with spectropolarimeter. The polarization of spectral lines that are pumped by the anisotropic radiation from the Sun is influenced by the magnetic realignment, which happens for magnetic field (<1G). As a result, the linear polarization becomes an excellent tracer of the embedded magnetic field. The method is illustrated by our synthetic observations of the Jupiter's Io and comet Halley. Polarization at each point was constructed according to the local magnetic field detected by spacecrafts. Both spatial and temporal variations of turbulent magnetic field can be traced with this technique as well. The influence of magnetic field on the polarization of scattered light is discussed in detail. For remote regions like the IBEX ribbons discovered at the boundary of interstellar medium, GSA provides a unique diagnostics of magnetic field.Comment: 11 pages, 19 figures, published in Astrophysics and Space Scienc

    Partnership or insanity: why do health partnerships do the same thing over and over again and expect a different result?

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    Objectives The paper reports on an empirical study of Health and Wellbeing Boards (HWBs) in England. Established by the Health and Social Care Act 2012, HWBs act as place-based hubs for leaders in health, social care, local government and other sectors to come together to address health improvement and the wider determinants of health. Methods We conducted a three-year study of HWBs (2015–2017) in five localities across England. This involved collecting qualitative data from semi-structured interviews with key actors in the HWBs at strategic and operational levels, and focus group sessions with voluntary-sector participants at each HWB. Results HWBs have largely followed the path of previous partnerships in terms of a lack of clear aims and objectives, lack of ownership and accountability by partners, and an absence of any significant impact on health outcomes. Conclusions Many of the features of unsuccessful partnership working were largely displayed by HWBs. Boards require more executive power and ownership from the bottom up if they are to have any real impact

    Pre-notched and corroded low cycle fatigue behaviour of a nickel based alloy for disc rotor applications

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    Currently there is doubt surrounding the suitability of chemically-induced stress independent pre-conditioning of specimens to simulate turbine corrosion prior to fatigue testing. the thick oxide scales developed using such techniques can lead to net section loss and typically a lack of grain boundary sulphide attack seen in components that experience stress. An alternative approach to a corrosion-fatigue test scenario is suggested by micro-notching fatigue specimens prior to low salt flux corrosion to form grain boundary sulphide particles within channel-like features akin to stress assisted morphologies. On fatigue testing, a trend was identified where a change of mechanism was observed. The grain boundary oxide likely formed in the wake of freshly precipitated sulphide particles fractures around segments of grains leading to a metal loss that contributes to a significant reduction in fatigue properties

    Gene mutations and three-dimensional structural analysis in 13 families with severe factor X deficiency

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    Factor X (FX) deficiency is a rare autosomal recessive disorder. The phenotype and genotype of 15 Iranian patients with FX deficiency from 13 unrelated families with a high frequency of consanguinity were analysed. Five different assays identified four patients from three families with a discrepancy between low-FX coagulant activity (FX:C) and higher-FX antigen (FX:Ag) (a type II deficiency). The remaining 11 patients had parallel reductions of FX:C and FX:Ag (a type I deficiency). Nine different homozygous candidate mutations were identified, of which eight were novel. The four type II cases were associated with an Arg()1)Thr missense mutation in the prepropeptide: Arg()1) is highly conserved in all vitamin K-dependent proteins. Four type I mutations (Gly78Asp, Cys81Tyr, Gly94Arg and Asp95Glu) were localized to the EGF-1 and EGF-2 domains, for which molecular views showed that the protein folding would be disrupted. The type I mutation Gly222Asp was localized in the catalytic domain of FX, and is sufficiently close to the Asp-His-Ser catalytic triad to disrupt its correct protein folding. The two type I splice site mutations were IVS1+3, A fi T and IVS2\u20133, T fi G. These novel homozygous FX mutations were consistent with their phenotypes and agree with experimental data from knockout mice, indicating that FX is an essential protein for survival

    The angular distribution of the reaction Μˉe+p→e++n\bar{\nu}_e + p \to e^+ + n

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    The reaction Μˉe+p→e++n\bar{\nu}_e + p \to e^+ + n is very important for low-energy (EÎœâ‰Č60E_\nu \lesssim 60 MeV) antineutrino experiments. In this paper we calculate the positron angular distribution, which at low energies is slightly backward. We show that weak magnetism and recoil corrections have a large effect on the angular distribution, making it isotropic at about 15 MeV and slightly forward at higher energies. We also show that the behavior of the cross section and the angular distribution can be well-understood analytically for EÎœâ‰Č60E_\nu \lesssim 60 MeV by calculating to O(1/M){\cal O}(1/M), where MM is the nucleon mass. The correct angular distribution is useful for separating Μˉe+p→e++n\bar{\nu}_e + p \to e^+ + n events from other reactions and detector backgrounds, as well as for possible localization of the source (e.g., a supernova) direction. We comment on how similar corrections appear for the lepton angular distributions in the deuteron breakup reactions Μˉe+d→e++n+n\bar{\nu}_e + d \to e^+ + n + n and Îœe+d→e−+p+p\nu_e + d \to e^- + p + p. Finally, in the reaction Μˉe+p→e++n\bar{\nu}_e + p \to e^+ + n, the angular distribution of the outgoing neutrons is strongly forward-peaked, leading to a measurable separation in positron and neutron detection points, also potentially useful for rejecting backgrounds or locating the source direction.Comment: 10 pages, including 5 figure

    Understanding the process of psychological development in youth athletes attending an intensive wrestling camp

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    This study used a grounded theory methodology to understand if and how psychological development in youth athletes was facilitated by an ‘intensive’ summer wrestling camp experience. The theoretical sampling approach involved 10 athlete participants of the camp, nine parents of athletes, the director of the camp, and four camp staff members, who took part in a series of interviews before, during, and after the camp. Two researchers were also embedded in the camp and attended all sessions, took detailed notes, collected camp materials, and conducted observations. Following a grounded theory analysis approach, a model is presented that outlines how youth participants’ developed psychological qualities from the coach created hallenges and adversity that were systematically designed to facilitate sport performance enhancement and life skills. Variations emerged in psychological antecedents and characteristics, how the challenging wrestling camp environment was interpreted and experienced, and how learning was transferred to sport and life domains outside of the wrestling camp. This study provided insight into a unique youth sport context that was able to simultaneously develop psychological qualities to be used as sport performance enhancement and life skills
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