174 research outputs found

    Analysis of Transaction Management Performance

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    There is currently much interest in incorporating transactions into both operating systems and general purpose programming languages. This paper provides a detailed examination of the design and performance of the“¢ transaction manager of the Camelot system. Camelot is a transaction facility that provides a rich model of transactions intended to support a wide variety of general-purpose applications. The transaction manager's principal function is to execute the protocols that ensure atomicity. The conclusions of this study are: a simple optimization to two-phase commit reduces logging activity of distributed transactions; non-blocking commit is practical for some applications; multithreaded design improves throughput provided that log batching is used; multi-casting reduces the variance of distributed commit protocols in a LAN environment; and the performance of transaction mechanisms such as Camelot depend heavily upon kernel performance

    A Business Plan for The Fitzgerald Institute

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    This piece seeks to develop a business strategy for the University of Akron\u27s Fitzgerald Institute for Entrepreneurship. The recommendations given were developed utilizing research on entrepreneurial education and the desires of students at the university

    Characterization of Spray A flame structure for parametric variations in ECN constant-volume vessels using chemiluminescence and laser-induced fluorescence

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    The transient and quasi-steady flame structure of reacting fuel sprays produced by single-hole injectors has been studied using chemiluminescence imaging and Planar Laser-Induced Fluorescence (PLIF) in various constant-volume facilities at different research institutes participating in the Engine Combustion Network (ECN). The evolution of the high-temperature flame has been followed based on chemiluminescence imaging of the excited-state hydroxyl radical (OH*), and PLIF of ground-state OH. Regions associated with low-temperature chemical reactions are visualized using formaldehyde (CH2O) PLIF with 355-nm excitation. We compare the results obtained by different research institutes under nominally identical experimental conditions and fuel injectors. In spite of design differences among the various experimental facilities, the results are consistent. This lends confidence to studies of transient behavior and parameter variations performed by individual research groups. We present results of the transient flame structures at Spray A reference conditions, and include parametric variations around this baseline, involving ambient temperature, oxygen concentration and injection pressure. Key results are the observed influence of an entrainment wave on the transient flame behavior, model-substantiated explanations for the high-intensity OH* lobes at the lift-off length and differences with OH PLIF, and a general analogy of the flame structures with a spray cone along which the flame tends to locate for the applied parametric variations

    Red-Cockaded Woodpecker Status and Management: West Gulf Coastal Plain and Interior Highlands

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    Red-cockaded woodpecker populations declined precipitously following European settlement and expansion and cutting of the original pine forests across the southeastern United States. By 1990 most residual populations lacked demographic viability, existed in degraded habitat, and were isolated from other populations. The primary causes of this situation were harvest of the original pine forests of the southeastern United States, conversion of forested lands to other uses, short-rotation silvicultural practices, and alteration of the fire regime in the regenerated forests. As social and legal mandates changed, management of red-cockaded woodpeckers became a higher priority. Intensive management for red-cockaded woodpeckers is currently practiced on most public and a few private lands that still support populations. Recent population trends and the current status of red-cockaded woodpeckers in Oklahoma, Arkansas, Texas, and Louisiana reflect historical factors and the efficacy of recent management

    School-based socio-emotional learning programs to prevent depression, anxiety and suicide among adolescents: a global cost-effectiveness analysis

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    Abstract Aims Preventing the occurrence of depression/anxiety and suicide during adolescence can lead to substantive health gains over the course of an individual person’s life. This study set out to identify the expected population-level costs and health impacts of implementing universal and indicated school-based socio-emotional learning (SEL) programs in different country contexts. Methods A Markov model was developed to examine the effectiveness of delivering universal and indicated school-based SEL programs to prevent the onset of depression/anxiety and suicide deaths among adolescents. Intervention health impacts were measured in healthy life years gained (HLYGs) over a 100-year time horizon. Country-specific intervention costs were calculated and denominated in 2017 international dollars (2017 I)underahealthsystemsperspective.CosteffectivenessfindingsweresubsequentlyexpressedintermsofI) under a health systems perspective. Cost-effectiveness findings were subsequently expressed in terms of I per HLYG. Analyses were conducted on a group of 20 countries from different regions and income levels, with final results aggregated and presented by country income group – that is, low and lower middle income countries (LLMICs) and upper middle and high-income countries (UMHICs). Uncertainty and sensitivity analyses were conducted to test model assumptions. Results Implementation costs ranged from an annual per capita investment of I0.10inLLMICstoI0.10 in LLMICs to I0.16 in UMHICs for the universal SEL program and I0.06inLLMICstoI0.06 in LLMICs to I0.09 in UMHICs for the indicated SEL program. The universal SEL program generated 100 HLYGs per 1 million population compared to 5 for the indicated SEL program in LLMICs. The cost per HLYG was I958inLLMICSandI958 in LLMICS and I2,006 in UMHICs for the universal SEL program and I11,123inLLMICsandI11,123 in LLMICs and I18,473 in UMHICs for the indicated SEL program. Cost-effectiveness findings were highly sensitive to variations around input parameter values involving the intervention effect sizes and the disability weight used to estimate HLYGs. Conclusions The results of this analysis suggest that universal and indicated SEL programs require a low level of investment (in the range of I0.05toI0.05 to I0.20 per head of population) but that universal SEL programs produce significantly greater health benefits at a population level and therefore better value for money (e.g., less than I$1,000 per HLYG in LLMICs). Despite producing fewer population-level health benefits, the implementation of indicated SEL programs may be justified as a means of reducing population inequalities that affect high-risk populations who would benefit from a more tailored intervention approach

    Healthcare workers' perspectives and practices regarding the disclosure of HIV status to children in Malawi: A cross-sectional study

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    Background: In 2011 the World Health Organisation recommended that children with a diagnosis of HIV be gradually informed about their HIV status between the ages of 6 and 12 years. However, to date, literature has focused mainly on primary caregiver and child experiences with HIV disclosure, little is known about healthcare workers' perspectives and practices of HIV status disclosure to children. The aim of this study was to assess healthcare workers' perspectives and practices regarding the disclosure of HIV status to children aged between 6 and 12 years in Malawi. Methods: A cross-sectional survey was used to collect data from 168 healthcare providers working in antiretroviral clinics in all government District and Tertiary Hospitals in Malawi. Participants were asked questions regarding their knowledge, practice, and barriers to HIV disclosure. Data were analysed using binary logistic regression. Results: Almost all healthcare workers (98%) reported that it was important to disclose HIV status to children. A significant proportion (37%) reported that they had never disclosed HIV status to a child and about half estimated that the rate of HIV disclosure at their facility was 25% or less. The main barriers to disclosure were lack of training on disclosure (85%) and lack of a standard tool for disclosure (84%). Female healthcare workers (aOR) 2.4; 95% CI: 1.1-5.5) and lack of training on disclosure (aOR 7.7; 95% CI: 3.4-10.7) were independently associated with never having disclosed HIV status to a child. Conclusions: This study highlights the need for providing appropriate training in HIV disclosure for healthcare workers and the provision of standardised disclosure materials

    Mycobacteria activate γδ T-cell anti-tumour responses via cytokines from type 1 myeloid dendritic cells: a mechanism of action for cancer immunotherapy

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    Attenuated and heat-killed mycobacteria display demonstrable activity against cancer in the clinic; however, the induced immune response is poorly characterised and potential biomarkers of response ill-defined. We investigated whether three mycobacterial preparations currently used in the clinic (BCG and heat-killed Mycobacterium vaccae and Mycobacterium obuense) can stimulate anti-tumour effector responses in human γδ T-cells. γδ T-cell responses were characterised by measuring cytokine production, expression of granzyme B and cytotoxicity against tumour target cells. Results show that γδ T-cells are activated by these mycobacterial preparations, as indicated by upregulation of activation marker expression and proliferation. Activated γδ T-cells display enhanced effector responses, as shown by upregulated granzyme B expression, production of the TH1 cytokines IFN-γ and TNF-α, and enhanced degranulation in response to susceptible and zoledronic acid-treated resistant tumour cells. Moreover, γδ T-cell activation is induced by IL-12, IL-1β and TNF-α from circulating type 1 myeloid dendritic cells (DCs), but not from type 2 myeloid DCs or plasmacytoid DCs. Taken together, we show that BCG, M. vaccae and M. obuense induce γδ T-cell anti-tumour effector responses indirectly via a specific subset of circulating DCs and suggest a mechanism for the potential immunotherapeutic effects of BCG, M. vaccae and M. obuense in cancer
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