200,359 research outputs found

    Isisekelo Sempilo study protocol for the effectiveness of HIV prevention embedded in sexual health with or without peer navigator support (Thetha Nami) to reduce prevalence of transmissible HIV amongst adolescents and young adults in rural KwaZulu-Natal: a 2 × 2 factorial randomised controlled trial

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    BACKGROUND: Antiretroviral therapy (ART) through universal test and treat (UTT) and HIV pre-exposure prophylaxis (PrEP) substantially reduces HIV-related mortality, morbidity and incidence. Effective individual-level prevention modalities have not translated into population-level impact in southern Africa due to sub-optimal coverage among adolescents and youth who are hard to engage. We aim to investigate the feasibility, acceptability, and preliminary population level effectiveness of HIV prevention services with or without peer support to reduce prevalence of transmissible HIV amongst adolescents and young adults in KwaZulu-Natal. METHODS: We are conducting a 2 × 2 factorial trial among young men and women aged 16-29 years, randomly selected from the Africa Health Research Institute demographic surveillance area. Participants are randomly allocated to one of four intervention combinations: 1) Standard of Care (SOC): nurse-led services for HIV testing plus ART if positive or PrEP for those eligible and negative; 2) Sexual and Reproductive Health (SRH): Baseline self-collected vaginal and urine samples with study-organized clinic appointments for results, treatment and delivery of HIV testing, ART and PrEP integrated with SRH services; 3) Peer-support: Study referral of participants to a peer navigator to assess their health, social and educational needs and provide risk-informed HIV prevention, including facilitating clinic attendance; or 4) SRH + peer-support. The primary outcomes for effectiveness are: (1) the proportion of individuals with infectious HIV at 12 months and (2) uptake of risk-informed comprehensive HIV prevention services within 60 days of enrolment. At 12 months, all participants will be contacted at home and the study team will collect a dried blood spot for HIV ELISA and HIV viral load testing. DISCUSSION: This trial will enable us to understand the relative importance of SRH and peer support in creating demand for effective and risk informed biomedical HIV prevention and preliminary data on their effectiveness on reducing the prevalence of transmissible HIV amongst all adolescents and youth. TRIAL REGISTRATION: Trial Registry: clincialtrials.gov. CLINICALTRIALS: gov Identifier NCT04532307 . Registered: March 2020

    Understanding the Relationship Between Peer Mentoring and Undergraduate Capitalization

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    Research has demonstrated the importance of various forms of mentoring across multiple contexts. However, the topic of informal peer mentors has not been sufficiently explored. This study investigated the role of peer mentors in encouraging participation in voluntary development activities (i.e., capitalization). An online survey was completed by 288 undergraduate students. As hypothesized, mentoring was positively related to high levels of participation in capitalization activities and intentions to mentor in the future, and capitalization participation was positively related to higher levels of student satisfaction, continuance commitment, and career involvement. Contrary to expectations, capitalization participation was not significantly related to affective commitment. However, the mentoring items did not appear to load as separate factors for psychosocial and career-related functions, preventing the testing of relationships with these specific dimensions of mentoring. Research implications, limitations, and future directions for research are discussed

    Mechanical Characterization of Fourth Generation Composite Humerus

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    Mechanical data on upper extremity surrogate bones, supporting use as biomechanical tools, is limited. The objective of this study was to characterize the structural behaviour of the fourth-generation composite humerus under simulated physiologic bending, specifically, stiffness, rigidity, and mid-diaphysial surface strains. Three humeri were tested in four-point bending, in anatomically defined anteroposterior (AP) and mediolateral (ML) planes. Stiffness and rigidity were derived using load–displacement data. Principal strains were determined at the anterior, posterior, medial, and lateral surfaces in the humeral mid-diaphysial transverse plane of one specimen using stacked rosettes. Linear structural behaviour was observed within the test range. Average stiffness and rigidity were greater in the ML (918 ± 18 N/mm; 98.4 ± 1.9 Nm2) than the AP plane (833 ± 16 N/mm; 89.3 ± 1.6 Nm2), with little inter-specimen variability. The ML/AP rigidity ratio was 1.1. Surface principal strains were similar at the anterior (5.41 µε/N) and posterior (5.43 µε/N) gauges for AP bending, and comparatively less for ML bending, i.e. 5.1 and 4.5 µε/N, at the medial and lateral gauges, respectively. This study provides novel strain and stiffness data for the fourth-generation composite humerus and also adds to published construct rigidity data. The presented results support the use of this composite bone as a tool for modelling and experimentation

    Lightweight SFRC benefitting from a pre-soaking and internal curing process

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    The presented research program is focused on the design of a structural lightweight fiber-reinforced concrete harnessing an internal curing process. Pre-soaked waste red ceramic fine aggregate and pre-soaked artificial clay expanded coarse aggregate were utilized for the creation of the mix. Copper-coated steel fiber was added to the mix by volume in amounts of 0.0%, 0.5%, 1.0%, and 1.5%. Test specimens in forms of cubes, cylinders, and beams were tested to specify the concrete characteristics. Such properties as consistency, compressive strength, splitting tensile strength, static and dynamic modulus of elasticity, flexural characteristics, and shear strength were of special interest. The achieved concrete can be classified as LC12/13. A strength class, according to fib Model Code, was also assigned to the concretes in question. The proposed method of preparation of concrete mix using only pre-soaked aggregate (with no extra water) proved to be feasible.Web of Science1224art. no. 415

    Rotor Bar Fault Monitoring Method Based on Analysis of Air-Gap Torques of Induction Motors

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    A robust method to monitor the operating conditions of induction motors is presented. This method utilizes the data analysis of the air-gap torque profile in conjunction with a Bayesian classifier to determine the operating condition of an induction motor as either healthy or faulty. This method is trained offline with datasets generated either from an induction motor modeled by a time-stepping finite-element (TSFE) method or experimental data. This method can effectively monitor the operating conditions of induction motors that are different in frame/class, ratings, or design from the motor used in the training stage. Such differences can include the level of load torque and operating frequency. This is due to a novel air-gap torque normalization method introduced here, which leads to a motor fault classification process independent of these parameters and with no need for prior information about the motor being monitored. The experimental results given in this paper validate the robustness and efficacy of this method. Additionally, this method relies exclusively on data analysis of motor terminal operating voltages and currents, without relying on complex motor modeling or internal performance parameters not readily available

    An investigation into usability and exclusivity issues of digital programmable thermostats

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    This is the pre-print version of the Article - Copyright @ 2011 Taylor & FrancisWith nearly 60% of domestic energy consumption relating to space heating, the interaction between users and their heating controls is crucial in reducing consumption. Yet, many heating controls are complex and exclude people due to the demands placed upon their capabilities in terms of vision, reach, dexterity and thinking. This study explores the scale of and reasons for user exclusion in relation to digital programmable thermostats. The Exclusion Calculator was used to estimate the percentage of the population excluded from the use of three products. Full user testing was then conducted to elicit specific usability problems of the devices. The participants were a group of 14 younger users (aged 24–44) and 10 older users (aged 62–75). The exclusion calculations underestimated the actual exclusion significantly for both age ranges (p<0.05). None of the older users were able to complete the programming of the thermostats. Additionally, the cognitive demands of these systems were considered using a subjective workload assessment method, based on the NASA Task Load Index, and were found to be excessive. In conclusion, this study makes recommendations to facilitate the design of more inclusive digital programmable thermostats. It is argued that such changes could result in reductions in domestic heat energy consumption.This work is funded by the ESPRC and Buro Happold

    Wear and Friction Modeling on Lifeboat Launch Systems

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    The RNLI provides search and rescue cover along the UK and RoI coast using a variety of lifeboats and launch techniques. In locations where there is no natural harbour it is necessary to use a slipway to launch the lifeboat into the sea. Lifeboat slipway stations consist of an initial section where the boat is held on rollers followed by an inclined keelway lined with low friction composite materials, the lifeboat is released from the top of the slipway and proceeds under its own weight into the water. The lifeboat is later recovered using a winch line. It is common to manually apply grease to the composite slipway lining before each launch and recovery in order to ensure sufficiently low friction for successful operation. With the introduction of the Tamar class lifeboat it is necessary to upgrade existing boathouses and standardise slipway operational procedures to ensure consistent operation. The higher contact pressures associated with the new lifeboat have led to issues of high friction and wear on the composite slipway linings and the manual application of grease to reduce friction is to be restricted due to environmental impact and cost factors. This paper presents a multidisciplinary approach to modelling slipway panel wear and friction using tribometer testing in conjunction with finite element analysis and slipway condition surveys to incorporate common real-world effects such as panel misalignments. Finally, it is shown that a freshwater lubrication system is effective, reducing cost and environmental impacts while maintaining good friction and wear performance
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