2,632 research outputs found

    Supporting Virtualisation Management through an Object Mapping Declarative Language Framework

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    Due to the inevitably vast scale of virtualised cloud computing systems, management of the numerous physical and virtual components that make up their underlying infrastructure may become unwieldy. Many software packages that have historically been installed on desktops / workstations for years are slowly but surely being ported to cloud computing. The virtualisation management problems that are apparent today are only set to worsen as cloud computing systems become ever more pervasive. Backing cloud computing systems are equally elaborate database systems, many platforms of which have made extensive use of distributed computing and virtualisation for years. The more recent emergence of virtualised big data systems with similarly vast scale problems has escalated the urgent requirement for creative management of the numerous physical and virtual components. The thesis will initially synopsise previous investigatory research concerning these emerging problems and studies the current disposition of virtualisation management including the associated concepts, strategies and technologies. The thesis then continues, to describe the structure and operation of an object mapping declarative language to support the management of these numerous physical and virtual components. The ultimate aim is to develop a Virtualisation Management System (VMS), a software framework that is fully extensible in nature and which combines the rich capability of an imperative assembly with the concise simplicity of a declarative language. It is through this declarative language that human interaction and decision making may be richly yet concisely specified before being converted through object mapping to the comparable imperative assembly for execution. It is also through parsing this declarative language that autonomic algorithms may be able to integrate with and operate the VMS through a suitably defined plug-in based mechanism. The thesis will ultimately demonstrate via scenarios both basic and complex that the VMS is able to specify, observe, regulate and adapt its virtualisation management domain to the changing disposition of the numerous physical and virtual components that constitute cloud computing and big data systems

    Why HIV Positive Patients on Antiretroviral Treatment and/or Cotrimoxazole Prophylaxis Use Traditional Medicine: Perceptions of Health Workers, Traditional Healers and Patients: A Study in Two Provinces of South Africa

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    The study explored the perceptions, knowledge and attitudes of patients, health workers and traditional healers about the use of traditional medicine and Anti Retroviral Therapy (ART). The study explored the perceptions, knowledge and attitudes of patients, health workers and traditional healers about the use of traditional medicine and Anti Retroviral Therapy (ART), using an exploratory qualitative design in two provinces of South Africa: an urban township health facility in the Western Cape, and a rural district hospital in KwaZulu-Natal (KZN) with antennal HIV rate of 32% and 28%’respectively. In-depth interviews were conducted with 14 participants: six HIV patients on ART and using Traditional Medicine(TM), two doctors, two nurses and four traditional healers. Two focus group discussions - one at each site - were held with community health workers who work with HIV-positive patients (Western Cape [5] and in KZN [4]). Patient said to have used Traditional Healing Practices (THP) before they were diagnosed with HIV, and some who have been diagnosed with HIV continue using TM in conjunction with ART and/or Cotrimoxazole prophylaxis. Patients preferred not to disclose THP to health professionals because of lack of support and understanding. Patients utilize THP because of family expectations, privacy and confidentiality, especially when they have not disclosed their HIV status. Healthcare professionals had strong negative opinions about THP, especially for HIV-positive patients. Traditional healers supported the patient’s rationale for THP use. This study revealed a need to better understand factors involved in patients’ choosing to use THP concurrently with ART

    The history of the Y chromosome in man

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    Studies of the Y chromosome over the past few decades have opened a window into the history of our species, through the reconstruction and exploitation of a patrilineal (Y-genealogical) tree based on several hundred single-nucleotide variants (SNVs). A new study validates, refines and extends this tree by incorporating >65,000 Y-linked variants identified in 1,244 men representing worldwide diversity

    Cerebral blood flow predicts differential neurotransmitter activity

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    Application of metabolic magnetic resonance imaging measures such as cerebral blood flow in translational medicine is limited by the unknown link of observed alterations to specific neurophysiological processes. In particular, the sensitivity of cerebral blood flow to activity changes in specific neurotransmitter systems remains unclear. We address this question by probing cerebral blood flow in healthy volunteers using seven established drugs with known dopaminergic, serotonergic, glutamatergic and GABAergic mechanisms of action. We use a novel framework aimed at disentangling the observed effects to contribution from underlying neurotransmitter systems. We find for all evaluated compounds a reliable spatial link of respective cerebral blood flow changes with underlying neurotransmitter receptor densities corresponding to their primary mechanisms of action. The strength of these associations with receptor density is mediated by respective drug affinities. These findings suggest that cerebral blood flow is a sensitive brain-wide in-vivo assay of metabolic demands across a variety of neurotransmitter systems in humans

    Metabolomic Profiling of Statin Use and Genetic Inhibition of HMG-CoA Reductase

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    Background Statins are first-line therapy for cardiovascular disease prevention, but their systemic effects across lipoprotein subclasses, fatty acids, and circulating metabolites remain incompletely characterized. Objectives This study sought to determine the molecular effects of statin therapy on multiple metabolic pathways. Methods Metabolic profiles based on serum nuclear magnetic resonance metabolomics were quantified at 2 time points in 4 population-based cohorts from the United Kingdom and Finland (N = 5,590; 2.5 to 23.0 years of follow-up). Concentration changes in 80 lipid and metabolite measures during follow-up were compared between 716 individuals who started statin therapy and 4,874 persistent nonusers. To further understand the pharmacological effects of statins, we used Mendelian randomization to assess associations of a genetic variant known to mimic inhibition of HMG-CoA reductase (the intended drug target) with the same lipids and metabolites for 27,914 individuals from 8 population-based cohorts. Results Starting statin therapy was associated with numerous lipoprotein and fatty acid changes, including substantial lowering of remnant cholesterol (80% relative to low-density lipoprotein cholesterol [LDL-C]), but only modest lowering of triglycerides (25% relative to LDL-C). Among fatty acids, omega-6 levels decreased the most (68% relative to LDL-C); other fatty acids were only modestly affected. No robust changes were observed for circulating amino acids, ketones, or glycolysis-related metabolites. The intricate metabolic changes associated with statin use closely matched the association pattern with rs12916 in the HMGCR gene (R2 = 0.94, slope 1.00 ± 0.03). Conclusions Statin use leads to extensive lipid changes beyond LDL-C and appears efficacious for lowering remnant cholesterol. Metabolomic profiling, however, suggested minimal effects on amino acids. The results exemplify how detailed metabolic characterization of genetic proxies for drug targets can inform indications, pleiotropic effects, and pharmacological mechanisms

    Cerebral relapse of metastatic gastrointestinal stromal tumor during treatment with imatinib mesylate: Case report

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    BACKGROUND: The management of unresectable or metastatic gastrointestinal stromal tumors (GISTs) has previously been difficult as they are resistant to conventional chemotherapy and radiation. The development of imatinib mesylate has made a major impact on the management of advanced GISTs. It is apparent that there are sanctuary sites such as the central nervous system where imatinib does not achieve adequate concentrations. We describe the case of a man with metastatic GIST who experienced multiple cerebral relapses of disease while systemic disease progression appeared to be controlled by imatinib. CASE PRESENTATION: A 47-year-old man presented in July 1999 with a jejunal GIST with multiple hepatic metastases. The jejunal primary was resected and after unsuccessful cytoreductive chemotherapy, the liver metastases were also resected in December 1999. The patient subsequently relapsed in August 2001 with symptomatic hepatic, subcutaneous gluteal, left choroidal and right ocular metastases all confirmed on CT and PET scanning. Biopsy confirmed recurrent GIST. MRI and lumbar puncture excluded central nervous system involvement. The patient was commenced on imatinib 400 mg bd in September 2001 through a clinical trial. The symptoms improved with objective PET and CT scan response until December 2002 when the patient developed a right-sided foot drop. MRI scan showed a left parasagittal tumor which was resected and confirmed histologically to be metastatic GIST. Imatinib was ceased pre-operatively due to the trial protocol but recommenced in February 2003 on a compassionate use program. The left parasagittal metastasis recurred and required subsequent re-excision in September 2003 and January 2004. Control of the systemic GIST was temporarily lost on reduction of the dose of imatinib (due to limited drug supply) but on increasing the dose back to 800 mg per day, systemic disease was stabilized for a period of time before generalised progression occurred. CONCLUSION: This case illustrates that the brain can be a sanctuary site to treatment of GISTs with imatinib. Maintaining dosing of imatinib in the face of isolated sites of disease progression is also important, as other metastatic sites may still be sensitive

    Anomaly/Transport in an Ideal Weyl gas

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    We study some of the transport processes which are specific to an ideal gas of relativistic Weyl fermions and relate the corresponding transport coefficients to various anomaly coefficients of the system. We propose that these transport processes can be thought of as arising from the continuous injection of chiral states and their subsequent adiabatic flow driven by vorticity. This in turn leads to an elegant expression relating the anomaly induced transport coefficients to the anomaly polynomial of the Ideal Weyl gas.Comment: 35 pages, JHEP forma

    Evidence for directional selection at a novel major histocompatibility class I marker in wild common frogs (Rana temporaria) exposed to a viral pathogen (Ranavirus).

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    (c) 2009 Teacher et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Whilst the Major Histocompatibility Complex (MHC) is well characterized in the anuran Xenopus, this region has not previously been studied in another popular model species, the common frog (Rana temporaria). Nor, to date, have there been any studies of MHC in wild amphibian host-pathogen systems. We characterise an MHC class I locus in the common frog, and present primers to amplify both the whole region, and specifically the antigen binding region. As no more than two expressed haplotypes were found in over 400 clones from 66 individuals, it is likely that there is a single class I locus in this species. This finding is consistent with the single class I locus in Xenopus, but contrasts with the multiple loci identified in axolotls, providing evidence that the diversification of MHC class I into multiple loci likely occurred after the Caudata/Anura divergence (approximately 350 million years ago) but before the Ranidae/Pipidae divergence (approximately 230 mya). We use this locus to compare wild populations of common frogs that have been infected with a viral pathogen (Ranavirus) with those that have no history of infection. We demonstrate that certain MHC supertypes are associated with infection status (even after accounting for shared ancestry), and that the diseased populations have more similar supertype frequencies (lower F(ST)) than the uninfected. These patterns were not seen in a suite of putatively neutral microsatellite loci. We interpret this pattern at the MHC locus to indicate that the disease has imposed selection for particular haplotypes, and hence that common frogs may be adapting to the presence of Ranavirus, which currently kills tens of thousands of amphibians in the UK each year
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