4,908 research outputs found

    Addressing the challenges of recurrent Tuberculosis in Malawi

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    Background Each year, approximately 10% of people diagnosed with tuberculosis (TB) globally have previously received TB treatment, and are prescribed a standardised WHO ‘Category II regimen’ which includes daily intramuscular injections of streptomycin. Treatment success rates on this re-treatment regimen are low, yet reasons for poor outcomes are not well understood. Currently data are lacking about appropriate ways to deliver long term injectable agents used as part of TB treatment. Methods The study was conducted in Malawi, a small country in South-Eastern Africa with a high TB burden and a generalised HIV epidemic. A cohort study prospectively recruited adult patients receiving retreatment regimen. Patients were assessed at baseline, 2 and 8 months. Multivariate logistic regression analysis was used to determine associations between clinical outcome and microbiologically confirmed TB, drug resistance, clinical features at presentation and medical co-morbidities. A pragmatic, individually randomised trial assessed hospital versus community-based care during the intensive phase of TB retreatment. In the community arm guardians were trained to deliver intramuscular injections of streptomycin at home. An economic evaluation was conducted from a societal perspective; and a qualitative evaluation involved in depth interviews with trial participants, key informant interviews, and observations. Results In the cohort study, the prevalence of drug resistance was 9.6%. The prevalence of co-morbidity was high (HIV 82.9%; antiretroviral therapy failure 37.5%; severe anaemia 22.2%; chronic lung disease 88.2%; renal impairment 33.8%). Ototoxicity developed in 35.9% and nephrotoxicity in 14.6%. In multivariate analysis, successful outcome was associated only with hypotension at presentation, but not microbiologically confirmed TB, drug resistance or other co-morbidities. In the trial, 93.2% of patients who received community-based care successfully completed 2 months treatment, compared to 96.0% managed in hospital (RD -0.03; 95%CI -0.09 - 0.03). The mean cost of hospital-based care was US1546perperson,comparedtoUS 1546 per person, compared to US 729.2 in the community. Community-based management reduced risk of catastrophic household costs by 84%. Qualitative data demonstrated social and financial benefits of community-based care. Conclusions This cohort study demonstrated a low prevalence of drug resistant TB but a high burden of medical co-morbidity in patients with recurrent TB in Malawi. Co-morbidity is likely to be contributing to poor outcomes on TB retreatment regimen. A novel community-based model of delivering injectable anti-TB drugs by training guardians to do injections at home is shown to be feasible, acceptable and highly cost effective

    BohlerÂŽs angle and the crucial angle of Gissane in paediatric population

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    Bohler angle and the crucial angle of Gissane are used on the evaluation of calcaneus fractures. However, few authors have described the variation of the angles when the calcaneus is growing. In this study, Bohler angle and the crucial angle of Gissane in paediatric population were measured using lateral foot radiographs of 429 patients, from 0 to 16 years of age. The control group was composed of 70 adult patients. The sample had a mean Bohler angle of 35.4° ± 5.9° and a mean crucial angle of Gissane of 110.5° ± 7.4°. The greater mean difference was identified for Bohler angle (8°) in the age group of 5 to 8 years (39.6° ± 5.7°) and for the crucial angle of Gissane (5°-6°) in the age group of 0 to 4 years (115.8° ± 7.3) (P < .05). The influence of the ossification centres on the geometry of the calcaneus across age groups makes Bohler angle and the crucial angle of Gissane higher in young children. The increase in Bohler angle points out the relative development of the posterior facet in young children and the importance of the reconstruction of the posterior facet height in the intra-articular calcaneus fractures

    An anisotropic hybrid non-perturbative formulation for 4D N = 2 supersymmetric Yang-Mills theories

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    We provide a simple non-perturbative formulation for non-commutative four-dimensional N = 2 supersymmetric Yang-Mills theories. The formulation is constructed by a combination of deconstruction (orbifold projection), momentum cut-off and matrix model techniques. We also propose a moduli fixing term that preserves lattice supersymmetry on the deconstruction formulation. Although the analogous formulation for four-dimensional N = 2 supersymmetric Yang-Mills theories is proposed also in Nucl.Phys.B857(2012), our action is simpler and better suited for computer simulations. Moreover, not only for the non-commutative theories, our formulation has a potential to be a non-perturbative tool also for the commutative four-dimensional N = 2 supersymmetric Yang-Mills theories.Comment: 32 pages, final version accepted in JHE

    Anonymous Graph Exploration with Binoculars

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    International audienceWe investigate the exploration of networks by a mobile agent. It is long known that, without global information about the graph, it is not possible to make the agent halts after the exploration except if the graph is a tree. We therefore endow the agent with binoculars, a sensing device that can show the local structure of the environment at a constant distance of the agent current location.We show that, with binoculars, it is possible to explore and halt in a large class of non-tree networks. We give a complete characterization of the class of networks that can be explored using binoculars using standard notions of discrete topology. This class is much larger than the class of trees: it contains in particular chordal graphs, plane triangulations and triangulations of the projective plane. Our characterization is constructive, we present an Exploration algorithm that is universal; this algorithm explores any network explorable with binoculars, and never halts in non-explorable networks

    SUSY Splits, But Then Returns

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    We study the phenomenon of accidental or "emergent" supersymmetry within gauge theory and connect it to the scenarios of Split Supersymmetry and Higgs compositeness. Combining these elements leads to a significant refinement and extension of the proposal of Partial Supersymmetry, in which supersymmetry is broken at very high energies but with a remnant surviving to the weak scale. The Hierarchy Problem is then solved by a non-trivial partnership between supersymmetry and compositeness, giving a promising approach for reconciling Higgs naturalness with the wealth of precision experimental data. We discuss aspects of this scenario from the AdS/CFT dual viewpoint of higher-dimensional warped compactification. It is argued that string theory constructions with high scale supersymmetry breaking which realize warped/composite solutions to the Hierarchy Problem may well be accompanied by some or all of the features described. The central phenomenological considerations and expectations are discussed, with more detailed modelling within warped effective field theory reserved for future work.Comment: 29 pages. Flavor and CP constraints on left-right symmetric structure briefly discussed. References adde

    Species Doublers as Super Multiplets in Lattice Supersymmetry: Exact Supersymmetry with Interactions for D=1 N=2

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    We propose a new lattice superfield formalism in momentum representation which accommodates species doublers of the lattice fermions and their bosonic counterparts as super multiplets. We explicitly show that one dimensional N=2 model with interactions has exact Lie algebraic supersymmetry on the lattice for all super charges. In coordinate representation the finite difference operator is made to satisfy Leibnitz rule by introducing a non local product, the ``star'' product, and the exact lattice supersymmetry is realized. The standard momentum conservation is replaced on the lattice by the conservation of the sine of the momentum, which plays a crucial role in the formulation. Half lattice spacing structure is essential for the one dimensional model and the lattice supersymmetry transformation can be identified as a half lattice spacing translation combined with alternating sign structure. Invariance under finite translations and locality in the continuum limit are explicitly investigated and shown to be recovered. Supersymmetric Ward identities are shown to be satisfied at one loop level. Lie algebraic lattice supersymmetry algebra of this model suggests a close connection with Hopf algebraic exactness of the link approach formulation of lattice supersymmetry.Comment: 34 pages, 2 figure

    Early Clinical and Subclinical Visual Evoked Potential and Humphrey's Visual Field Defects in Cryptococcal Meningitis.

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    Cryptococcal induced visual loss is a devastating complication in survivors of cryptococcal meningitis (CM). Early detection is paramount in prevention and treatment. Subclinical optic nerve dysfunction in CM has not hitherto been investigated by electrophysiological means. We undertook a prospective study on 90 HIV sero-positive patients with culture confirmed CM. Seventy-four patients underwent visual evoked potential (VEP) testing and 47 patients underwent Humphrey's visual field (HVF) testing. Decreased best corrected visual acuity (BCVA) was detected in 46.5% of patients. VEP was abnormal in 51/74 (68.9%) right eyes and 50/74 (67.6%) left eyes. VEP P100 latency was the main abnormality with mean latency values of 118.9 (±16.5) ms and 119.8 (±15.7) ms for the right and left eyes respectively, mildly prolonged when compared to our laboratory references of 104 (±10) ms (p<0.001). Subclinical VEP abnormality was detected in 56.5% of normal eyes and constituted mostly latency abnormality. VEP amplitude was also significantly reduced in this cohort but minimally so in the visually unimpaired. HVF was abnormal in 36/47 (76.6%) right eyes and 32/45 (71.1%) left eyes. The predominant field defect was peripheral constriction with an enlarged blind spot suggesting the greater impact by raised intracranial pressure over that of optic neuritis. Whether this was due to papilloedema or a compartment syndrome is open to further investigation. Subclinical HVF abnormalities were minimal and therefore a poor screening test for early optic nerve dysfunction. However, early optic nerve dysfunction can be detected by testing of VEP P100 latency, which may precede the onset of visual loss in CM

    Lattice formulation of two-dimensional N=(2,2) super Yang-Mills with SU(N) gauge group

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    We propose a lattice model for two-dimensional SU(N) N=(2,2) super Yang-Mills model. We start from the CKKU model for this system, which is valid only for U(N) gauge group. We give a reduction of U(1) part keeping a part of supersymmetry. In order to suppress artifact vacua, we use an admissibility condition.Comment: 16 pages, 3 figures; v2: typo crrected; v3: 18 pages, a version to appear in JHE

    A qualitative evaluation of hospital versus community-based management of patients on injectable treatments for tuberculosis

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    Abstract Background Patients being treated for recurrent or multidrug-resistant tuberculosis (TB) require long courses of injectable anti-tuberculous agents. In order to maintain strong TB control programmes, it is vital that the experiences of people who receive long-term injectables for TB are well understood. To investigate the feasibility of a novel model of care delivery, a clinical trial (The TB-RROC Study) was conducted at two central hospitals in Malawi. Hospital-based care was compared to a community-based approach for patients on TB retreatment in which ‘guardians’ (patient-nominated lay people) were trained to deliver injections to patients at home. This study is the qualitative evaluation of the TB-RROC trial. It examines the experiences of people receiving injectables as part of TB treatment delivered in hospital and community-based settings. Methods A qualitative evaluation of the TB-RROC intervention was conducted using phenomenographic methods. Trial participants were purposively sampled, and in-depth interviews were conducted with patients and guardians in both arms of the trial. Key informant interviews and observations in the wards and community were performed. Thematic content analysis was used to derive analytical themes. Results Fourteen patients, 12 guardians and 9 key informants were interviewed. Three key themes relating to TB retreatment emerged: medical experiences (including symptoms, treatment, and HIV); the effects of the physical environment (conditions on the ward, disruption to daily routines and livelihoods); and trust (in other people, the community and in the health system). Experiences were affected by the nature of a person’s prior role in their community and resulted in a range of emotional responses. Patients and guardians in the community benefited from better environment, social interactions and financial stability. Concerns were expressed about the potential for patients’ health or relationships to be adversely affected in the community. These potential concerns were rarely realised. Conclusions Guardian administered intramuscular injections were safe and well received. Community-based care offered many advantages over hospital-based care for patients receiving long-term injectable treatment for TB and their families
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