150 research outputs found

    Coleman - de Luccia instanton of the second order in a brane world

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    The second order Coleman - de Luccia instanton and its action in the Randall - Sundrum type II model are investigated and the comparison with the results in Einstein's general relativity is done in the present paper.Comment: 4 pages, accepted in IJT

    The Skyrme Energy Functional and Naturalness

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    Recent studies show that successful relativistic mean-field models of nuclei are consistent with naive dimensional analysis and naturalness, as expected in low-energy effective field theories of quantum chromodynamics. The nonrelativistic Skyrme energy functional is found to have similar characteristics.Comment: 8 pages, REVTeX 3.0 with epsf.sty, plus 2 figure

    False vacuum decay with gravity in a critical case

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    The vacuum decay in a de Sitter universe is studied within semiclassical approximation for the class of effective inflaton potentials whose curvature at the top is close to a critical value. By comparing the actions of the Hawking - Moss instanton and the Coleman - de Luccia instanton(s) the mode of vacuum decay is determined. The case when the fourth derivative of the effective potential at its top is less than a critical value is discussed.Comment: 10 pages, 8 figures, minor changes don

    Radical, Reformist, and Garden-Variety Neoliberal: Coming to Terms with Urban Agriculture’s Contradictions

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    For many activists and scholars, urban agriculture in the Global North has become synonymous with sustainable food systems, standing in opposition to the dominant industrial agri-food system. At the same time, critical social scientists increasingly argue that urban agriculture programmes, by filling the void left by the rolling back of the social safety net, underwrite neoliberalisation. I argue that such contradictions are central to urban agriculture. Drawing on existing literature and fieldwork in Oakland, CA, I explain how urban agriculture arises from a protective counter-movement, while at the same time entrenching the neoliberal organisation of contemporary urban political economies through its entanglement with multiple processes of neoliberalisation. By focusing on one function or the other, however, rather than understanding such contradictions as internal and inherent, we risk undermining urban agriculture\u27s transformative potential. Coming to terms with its internal contradictions can help activists, policy-makers and practitioners better position urban agriculture within coordinated efforts for structural change, one of many means to an end rather than an end unto itself

    Engaging Caregivers and Providers of Children With Sickle Cell Anemia in Shared Decision Making for Hydroxyurea: Protocol for a Multicenter Randomized Controlled Trial

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    BACKGROUND: Sickle cell anemia (SCA) is a genetic blood disorder that puts children at a risk of serious medical complications, early morbidity and mortality, and high health care utilization. Until recently, hydroxyurea was the only disease-modifying treatment for this life-threatening disease and has remained the only option for children younger than 5 years. Evidence-based guidelines recommend using a shared decision-making (SDM) approach for offering hydroxyurea to children with SCA (HbSS or HbS/ÎČ0 thalassemia) aged as early as 9 months. However, the uptake remains suboptimal, likely because caregivers lack information about hydroxyurea and have concerns about its safety and potential long-term side effects. Moreover, clinicians do not routinely receive training or tools, especially those that provide medical evidence and consider caregivers' preferences and values, to facilitate a shared discussion with caregivers. OBJECTIVE: The aim of this study is to understand how best to help parents of young children with sickle cell disease and their clinicians have a shared discussion about hydroxyurea (one that considers medical evidence and parent values and preferences). METHODS: We designed our study to compare the effectiveness of two methods for disseminating hydroxyurea guidelines to facilitate SDM: a clinician pocket guide (ie, usual care) and a clinician hydroxyurea SDM toolkit (H-SDM toolkit). Our primary outcomes are caregiver reports of decisional uncertainty and knowledge of hydroxyurea. The study also assesses the number of children (aged 0-5 years) who were offered and prescribed hydroxyurea and the resultant health outcomes. RESULTS: The Ethics Committee of the Cincinnati Children's Hospital Medical Center approved this study in November 2017. As of February 2021, we have enrolled 120 caregiver participants. CONCLUSIONS: The long-term objective of this study is to improve the quality of care for children with SCA. Using multicomponent dissemination methods developed in partnership with key stakeholders and designed to address barriers to high-quality care, caregivers of patients with SCA can make informed and shared decisions about their health. TRIAL REGISTRATION: ClinicalTrials.gov NCT03442114; https://clinicaltrials.gov/ct2/show/NCT03442114. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/27650

    Hamburg's Spaces of Danger: Race, Violence and Memory in a Contemporary Global City

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    Germany today is experiencing the strongest upsurge of right-wing populism since the second world war, most notably with the rise of Pegida and Alternative fĂŒr Deutschland. Yet wealthy global cities like Hamburg continue to present themselves as the gatekeepers of liberal progress and cosmopolitan openness. This article argues that Hamburg’s urban boosterism relies on, while simultaneously obscuring, the same structures of racial violence that embolden reactionary movements. Drawing on the work of Walter Benjamin and Allan Pred, we present an archaeology of Hamburg’s landscape, uncovering some of its ‘spaces of danger’––sites layered with histories of violence, many of which lie buried and forgotten. We find that these spaces, when they become visible, threaten to undermine Hamburg’s cosmopolitan narrative. They must, as a result, be continually erased or downplayed in order to secure the city as an attractive site for capital investment. To illustrate this argument, we give three historical examples: Hamburg’s role in the Hanseatic League during the medieval and early modern period; the city under the Nazi regime; and the recent treatment of Black African refugees. The article’s main contribution is to better situate issues of historical landscape, collective memory and racialized violence within the political economy of today’s global city

    The geographies of food banks in the meantime

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    The authors gratefully acknowledge the support given by the British Academy for this research (grant no. SG131950). The ‘Emergency Food Provision in the UK’ research includes: over eighteen months of ethnographic research in a Trussell Trust Foodbank; a national survey of the Trussell Trust Network and Independent food banks (and other food aid providers); and in-depth interviews with food bank managers, volunteers and service-users in London, Bristol, Leicestershire, South Wales, Devon, and Cornwall

    Impact of technology-based interventions for children and young people with type 1 diabetes on key diabetes self-management behaviours and prerequisites: A systematic review

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    Background The role of technology in the self-management of type 1 diabetes mellitus (T1DM) among children and young people is not well understood. Interventions should aim to improve key diabetes self-management behaviours (self-management of blood glucose, insulin administration, physical activity and dietary behaviours) and prerequisites (psychological outcomes and HbA1c) highlighted in the UK guidelines of the National Institute for Health and Care Excellence (NICE) for management of T1DM. The purpose was to identify evidence to assess the effectiveness of technological tools in promoting aspects of these guidelines amongst children and young people. Methods A systematic review of English language articles was conducted using the following databases: Web of Science, PubMed, Scopus, NUSearch, SAGE Journals, SpringerLink, Google Scholar, Science Direct, Sport Discus, Embase, Psychinfo and Cochrane Trials. Search terms included paediatric, type one diabetes, technology, intervention and various synonyms. Included studies examined interventions which supplemented usual care with a health care strategy primarily delivered through a technology-based medium (e.g. mobile phone, website, activity monitor) with the aim of engaging children and young people with T1DM directly in their diabetes healthcare. Studies did not need to include a comparator condition and could be randomised, non-randomised or cohort studies but not single-case studies. Results Of 30 included studies (21 RCTs), the majority measured self-monitoring of blood glucose monitoring (SMBG) frequency, clinical indicators of diabetes self-management (e.g. HbA1c) and/or psychological or cognitive outcomes. The most positive findings were associated with technology-based health interventions targeting SMBG as a behavioural outcome, with some benefits found for clinical and/or psychological diabetes self-management outcomes. Technological interventions were well accepted by children and young people. For the majority of included outcomes, clinical relevance was deemed to be little or none. Conclusions More research is required to assess which elements of interventions are most likely to produce beneficial behavioural outcomes. To produce clinically relevant outcomes, interventions may need to be delivered for at least 1 year and should consider targeting individuals with poorly managed diabetes. It is not possible to determine the impact of technology-based interventions on insulin administration, dietary habits and/or physical activity behaviour due to lack of evidence

    Contested space: The contradictory political dynamics of food banking in the UK

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    This paper offers a critical reappraisal of the politics of food banking in the UK. Existing work has raised concerns about the institutionalisation of food banks, with charitable assistance apparently – even if inadvertently – undermining collectivist welfare and deflecting attention from fundamental injustices in the food system. This paper presents original ethnographic work that examines the neglected politics articulated within food banks themselves. Conceptualising food banks as potential spaces of encounter where predominantly middle-class volunteers come into contact with ‘poor others’ (Lawson and Elwood, 2013), we illustrate the ways food banks may both reinforce but also rework and generate new, ethical and political attitudes, beliefs and identities. We also draw attention to the limits of these progressive possibilities and examine the ways in which some food banks continue to operate within a set of highly restrictive, and stigmatising, welfare technologies. By highlighting the contradictory dynamics at work in food bank organisations, and among food bank volunteers and clients, we suggest the political role of food banks warrants neither uncritical celebration nor outright dismissal. Rather, food banks represent a highly ambiguous political space still in the making and open to contestatio

    Test beam performance of a CBC3-based mini-module for the Phase-2 CMS Outer Tracker before and after neutron irradiation

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    The Large Hadron Collider (LHC) at CERN will undergo major upgrades to increase the instantaneous luminosity up to 5–7.5×1034^{34} cm−2^{-2}s−1^{-1}. This High Luminosity upgrade of the LHC (HL-LHC) will deliver a total of 3000–4000 fb-1 of proton-proton collisions at a center-of-mass energy of 13–14 TeV. To cope with these challenging environmental conditions, the strip tracker of the CMS experiment will be upgraded using modules with two closely-spaced silicon sensors to provide information to include tracking in the Level-1 trigger selection. This paper describes the performance, in a test beam experiment, of the first prototype module based on the final version of the CMS Binary Chip front-end ASIC before and after the module was irradiated with neutrons. Results demonstrate that the prototype module satisfies the requirements, providing efficient tracking information, after being irradiated with a total fluence comparable to the one expected through the lifetime of the experiment
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