881 research outputs found

    Contextual influences on social enterprise management in rural and urban communities

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    The idea that difference exists between rural and urban enterprise activity is not new, the obvious comparators are measures such as social architecture, resource availability and accessibility. However, when the concept and practice of management in social enterprise is compared in these two contexts then there is opportunity to further our understanding of the contextual challenges encountered by social enterprise. In this paper six cases studies are compared and analysed: three cases are urban social enterprises and three classified as remote rural social enterprises. The urban cases are social enterprises located around Glasgow in the west of Scotland and are compared with three remote rural location studies, one on the Scottish mainland peninsula, the other in northern Scotland and the final case on a Scottish western island. We conclude that the main differences between remote rural and urban management of social enterprise are heavily nuanced by in-migration levels in both rural and urban locations, leadership and community needs and therefore deserving of context relevant policy

    Evaluation of Failed ACL Reconstruction: An Updated Review

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    Bryson Kemler,1 Carlo Coladonato,1 John Hayden Sonnier,1 Michael P Campbell,1 Danielle Darius,2 Brandon J Erickson,1 Fotios Paul Tjoumakaris,1 Kevin B Freedman1 1Department of Orthopaedic Surgery, Rothman Institute, Philadelphia, PA, USA; 2Department of Education, Drexel University College of Medicine, Philadelphia, PA, USACorrespondence: Kevin B Freedman, Rothman Orthopaedics at Thomas Jefferson University, 825 Old Lancaster Road, Suite 200, Bryn Mawr, Philadelphia, PA, 19010, USA, Email [email protected]: Failure rates among primary Anterior Cruciate Ligament Reconstruction (ACLR) range from 3.2% to 11.1%. Recently, there has been increased focus on surgical and anatomic considerations which predispose patients to failure, including excessive posterior tibial slope (PTS), unaddressed high-grade pivot shift, and improper tunnel placement. The purpose of this review was to provide a current summary and analysis of the literature regarding patient-related and technical factors surrounding revision ACLR, rehabilitation considerations, overall outcomes and return to sport (RTS) for patients who undergo revision ACLR. There is a convincingly higher re-tear and revision rate in patients who undergo ACLR with allograft than autograft, especially amongst the young, athletic population. Unrecognized Posterior Cruciate Ligament (PLC) injury is a common cause of ACLR failure and current literature suggests concurrent operative management of high-grade PLC injuries. Given the high rates of revision surgery in young active patients who return to pivoting sports, the authors recommend strong consideration of a combined ACLR + Anterolateral Ligament (ALL) or Lateral extra-articular tenodesis (LET) procedure in this population. Excessive PTS has been identified as an independent risk factor for ACL graft failure. Careful consideration of patient-specific factors such as age and activity level may influence the success of ACL reconstruction. Additional technical considerations including graft choice and fixation method, tunnel position, evaluation of concomitant posterolateral corner and high-grade pivot shift injuries, and the role of excessive posterior tibial slope may play a significant role in preventing failure.Keywords: ACL, anterior cruciate ligament, anterior cruciate ligament reconstruction, failed ACL graft, posterior tibial slope, revision ACL reconstructio

    Large Anomalous Hall effect in a silicon-based magnetic semiconductor

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    Magnetic semiconductors are attracting high interest because of their potential use for spintronics, a new technology which merges electronics and manipulation of conduction electron spins. (GaMn)As and (GaMn)N have recently emerged as the most popular materials for this new technology. While Curie temperatures are rising towards room temperature, these materials can only be fabricated in thin film form, are heavily defective, and are not obviously compatible with Si. We show here that it is productive to consider transition metal monosilicides as potential alternatives. In particular, we report the discovery that the bulk metallic magnets derived from doping the narrow gap insulator FeSi with Co share the very high anomalous Hall conductance of (GaMn)As, while displaying Curie temperatures as high as 53 K. Our work opens up a new arena for spintronics, involving a bulk material based only on transition metals and Si, and which we have proven to display a variety of large magnetic field effects on easily measured electrical properties.Comment: 19 pages with 5 figure

    Pathways of carbon and energy metabolism of the epibiotic community associated with the deep-sea hydrothermal vent shrimp Rimicaris exoculata

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    © The Authors, 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 6 (2011): e16018, doi:10.1371/journal.pone.0016018.The shrimp Rimicaris exoculata dominates the faunal biomass at many deep-sea hydrothermal vent sites at the Mid-Atlantic Ridge. In its enlarged gill chamber it harbors a specialized epibiotic bacterial community for which a nutritional role has been proposed. We analyzed specimens from the Snake Pit hydrothermal vent field on the Mid-Atlantic Ridge by complementing a 16S rRNA gene survey with the analysis of genes involved in carbon, sulfur and hydrogen metabolism. In addition to Epsilon- and Gammaproteobacteria, the epibiotic community unexpectedly also consists of Deltaproteobacteria of a single phylotype, closely related to the genus Desulfocapsa. The association of these phylogenetic groups with the shrimp was confirmed by fluorescence in situ hybridization. Based on functional gene analyses, we hypothesize that the Gamma- and Epsilonproteobacteria are capable of autotrophic growth by oxidizing reduced sulfur compounds, and that the Deltaproteobacteria are also involved in sulfur metabolism. In addition, the detection of proteobacterial hydrogenases indicates the potential for hydrogen oxidation in these communities. Interestingly, the frequency of these phylotypes in 16S rRNA gene clone libraries from the mouthparts differ from that of the inner lining of the gill chamber, indicating potential functional compartmentalization. Our data show the specific association of autotrophic bacteria with Rimicaris exoculata from the Snake Pit hydrothermal vent field, and suggest that autotrophic carbon fixation is contributing to the productivity of the epibiotic community with the reductive tricarboxylic acid cycle as one important carbon fixation pathway. This has not been considered in previous studies of carbon fixation and stable carbon isotope composition of the shrimp and its epibionts. Furthermore, the co-occurrence of sulfur-oxidizing and sulfur-reducing epibionts raises the possibility that both may be involved in the syntrophic exchange of sulfur compounds, which could increase the overall efficiency of this epibiotic community.Funding was provided through NSF grant OCE-0452333 and the Alfried Krupp Wissenschaftskolleg Greifswald, Germany (SMS), the Max Planck Society, the German Research Foundation (DFG) Cluster of Excellence at Marum, and MOMARnet (ND, JMP), and IFM-GEOMAR (MH, JFI)

    Deep-Inelastic Inclusive ep Scattering at Low x and a Determination of alpha_s

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    A precise measurement of the inclusive deep-inelastic e^+p scattering cross section is reported in the kinematic range 1.5<= Q^2 <=150 GeV^2 and 3*10^(-5)<= x <=0.2. The data were recorded with the H1 detector at HERA in 1996 and 1997, and correspond to an integrated luminosity of 20 pb^(-1). The double differential cross section, from which the proton structure function F_2(x,Q^2) and the longitudinal structure function F_L(x,Q^2) are extracted, is measured with typically 1% statistical and 3% systematic uncertainties. The measured partial derivative (dF_2(x,Q^2)/dln Q^2)_x is observed to rise continuously towards small x for fixed Q^2. The cross section data are combined with published H1 measurements at high Q^2 for a next-to-leading order DGLAP QCD analysis.The H1 data determine the gluon momentum distribution in the range 3*10^(-4)<= x <=0.1 to within an experimental accuracy of about 3% for Q^2 =20 GeV^2. A fit of the H1 measurements and the mu p data of the BCDMS collaboration allows the strong coupling constant alpha_s and the gluon distribution to be simultaneously determined. A value of alpha _s(M_Z^2)=0.1150+-0.0017 (exp) +0.0009-0.0005 (model) is obtained in NLO, with an additional theoretical uncertainty of about +-0.005, mainly due to the uncertainty of the renormalisation scale.Comment: 68 pages, 24 figures and 18 table
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