5,032 research outputs found

    A Case of Successful Surgical Treatment of Migraine Headaches in a Patient with Sporadic Pulmonary Arteriovenous Malformations

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    Pulmonary arteriovenous malformations (PAVMs) are thin-walled aneurysms caused by abnormal communication between the pulmonary arteries and veins. Migraine headaches are sometimes the presenting clinical manifestation of PAVMs. Although embolotherapy, using detachable balloons or stainless steel coils, is generally accepted as the best choice for the treatment of multiple PAVMs, the mode of intervention for solitary PAVMs remains a subject of debate. We present a 43-yr-old woman with a 10-yr history of chronic migraines and dyspnea on exertion. She was discovered to have a large solitary centrally located PAVM, placing her at high risk of complications if she were to undergo percutaneous transcatheter embolization. She underwent successful surgical resection of her right middle lobe without complications, resulting in subsequent symptomatic improvement

    Accessibility of antiretroviral therapy in Ghana: Convenience of access

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    The convenience of accessing antiretroviral therapy (ART) is important for initial access to care and subsequent adherence to ART. We conducted a qualitative study of people living with HIV/AIDS (PLWHA) and ART healthcare providers in Ghana in 2005. The objective of this study was to explore the participants’ perceived convenience of accessing ART by PLWHA in Ghana. The convenience of accessing ART was evaluated from the reported travel and waiting times to receive care, the availability, orotherwise, of special considerations, with respect to the waiting time to receive care, for those PLWHA who were in active employment in the formal sector, the frequency of clinic visits before and after initiating ART, and whether the PLWHA saw the same or different providers at each clinic visit (continuity of care). This qualitative study used in-depth interviews based on Yin’s case-study research design to collect data from 20 PLWHA and 24 ART healthcare providers as study participants. . Reported travel time to receive ART services ranged from 2 to 12 h for 30% of the PLWHA.. Waiting time to receive care was from 4 to 9 h. . While known government workers, such as teachers, were attended to earlier in some of the centres, this was not a consistent practice in all the four ART centres studied. . The PLWHA corroborated the providers’ description of the procedure for initiating and monitoring ART in Ghana. . PLWHA did not see the same provider every time, but they were assured that this did not compromise the continuity of their care. Our study suggests that convenience of accessing ART is important to both PLWHA and ART healthcare providers, but the participants alluded to other factors, including open provider–patient communication, which might explain the PLWHA’sunderstanding of the constraints under which they were receiving care. The current nation-wide coverage of the ART programme in Ghana, however, calls for the replication of this study to identify possible perception changes over time that may need attention. Our study findings can inform interventions to promote access to ART, especially in Africa

    The Role of Modelling and Simulation in the Preparations for Flight Trials Aboard the Queen Elizabeth Class Aircraft Carriers

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    This paper provides a brief overview of how modelling and simulation has been used to inform preparations for First of Class Flight Trials (FOCFT) aboard HMS Queen Elizabeth, the first of the United Kingdom’s two new Queen Elizabeth Class aircraft carriers, from the perspective of a collaborative research programme undertaken by industry and academia to develop high-fidelity simulations of the carrier’s ‘airwake’.  Computer modelling of the unsteady air flow over the carrier, and of the aircraft flight dynamics, have been integrated into high-fidelity flight simulators at BAE Systems Warton, and at the University of Liverpool.  The Queen Elizabeth Class (QEC) carriers have primarily been designed to operate the Short Take-Off and Vertical Landing (STOVL) variant of the Lockheed Martin F-35 Lightning II multirole fighter aircraft and will also operate a range of rotary-wing assets.  Computational Fluid Dynamics (CFD) has been used to compute the time-varying air flow over and around the 280m long ship, along the F-35B landing approach path and up to 400m astern of the ship.  The paper shows a selection of results from the full-scale CFD analysis, and the results from a small-scale experiment that was conducted to provide confidence in the validity of the computed airwakes.  The QEC airwakes have been employed by BAE Systems in its fixed-wing flight simulator at Warton, where test pilots have conducted simulated deck landings for a variety of wind over deck conditions, so providing experience for F-35B test pilots and the ship’s Flying Control (FLYCO) crew ahead of FOCFT, which will be conducted later this year.  Airwakes have also been implemented in the HELIFLIGHT-R flight simulator at the University of Liverpool, where helicopter landings to the QEC have been simulated using a generic medium-weight maritime-helicopter model. A selection of results from the helicopter flight simulator trials is presented in terms of the workload ratings reported by test pilots, and these are related to the characteristics of the computed airwake at the landing spots tested.  The paper demonstrates how modelling and simulation can be used to reduce both the risk and cost of flight trials, by informing the FOCFT planning process, and by highlighting, in advance of the trials, which wind speed and azimuth combinations may require more focus.  </jats:p

    Two stages of parafoveal processing during reading: Evidence from a display change detection task

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    We used a display change detection paradigm (Slattery, Angele, & Rayner Human Perception and Performance, 37, 1924–1938 2011) to investigate whether display change detection uses orthographic regularity and whether detection is affected by the processing difficulty of the word preceding the boundary that triggers the display change. Subjects were significantly more sensitive to display changes when the change was from a nonwordlike preview than when the change was from a wordlike preview, but the preview benefit effect on the target word was not affected by whether the preview was wordlike or nonwordlike. Additionally, we did not find any influence of preboundary word frequency on display change detection performance. Our results suggest that display change detection and lexical processing do not use the same cognitive mechanisms. We propose that parafoveal processing takes place in two stages: an early, orthography-based, preattentional stage, and a late, attention-dependent lexical access stage

    No Evidence for Spread of Plasmodium falciparum Artemisinin Resistance to Savannakhet Province, Southern Laos

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    We conducted an open-label, randomized clinical trial to assess parasite clearance times (PCT) and the efficacy of 4 mg/kg (group 1, n = 22) and 2 mg/kg (group 2, n = 22) of oral artesunate for three days followed by artemether-lumefantrine in patients with uncomplicated Plasmodium falciparum malaria at Xepon Interdistrict Hospital, Savannakhet Province in southern Laos. Slides were read in duplicate. The overall mean (95% confidence interval; range) PCT in hours was 23.2 (21.2–25.3; 12–46) and 22.4 (20.3–24.5; 12–46) for the first and second microscopists, respectively (P = 0.57). Ten (23%) patients remained parasitemic on day 1 after treatment (4 [18%] in group 1 and 6 [27%] in group 2; P = 0.47). No patient had patent asexual parasitemia on the second and third days of treatment. The 42-day polymerase chain reaction–corrected cure rates were 100% in both treatment groups. Serious adverse events did not develop during or after treatment in any patients. In conclusion, no evidence of P. falciparum in vivo resistance to artesunate was found in southern Laos

    Evaluation of Rapid Diagnostics for Plasmodium falciparum and P. vivax in Mae Sot Malaria Endemic Area, Thailand

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    Prompt and accurate diagnosis of malaria is the key to prevent disease morbidity and mortality. This study was carried out to evaluate diagnostic performance of 3 commercial rapid detection tests (RDTs), i.e., Malaria Antigen Pf/Panâ„¢, Malaria Ag-Pfâ„¢, and Malaria Ag-Pvâ„¢ tests, in comparison with the microscopic and PCR methods. A total of 460 blood samples microscopically positive for Plasmodium falciparum (211 samples), P. vivax (218), mixed with P. falciparum and P. vivax (30), or P. ovale (1), and 124 samples of healthy subjects or patients with other fever-related infections, were collected. The sensitivities of Malaria Ag-Pfâ„¢ and Malaria Antigen Pf/Panâ„¢ compared with the microscopic method for P. falciparum or P. vivax detection were 97.6% and 99.0%, or 98.6% and 99.0%, respectively. The specificities of Malaria Ag-Pfâ„¢, Malaria Ag-Pvâ„¢, and Malaria Antigen Pf/Panâ„¢ were 93.3%, 98.8%, and 94.4%, respectively. The sensitivities of Malaria Ag-Pfâ„¢, Malaria Antigen Pf/Panâ„¢, and microscopic method, when PCR was used as a reference method for P. falciparum or P. vivax detection were 91.8%, 100%, and 96.7%, or 91.9%, 92.6%, and 97.3%, respectively. The specificities of Malaria Ag-Pfâ„¢, Malaria Ag-Pvâ„¢, Malaria Antigen Pf/Panâ„¢, and microscopic method were 66.2%, 92.7%, 73.9%, and 78.2%, respectively. Results indicated that the diagnostic performances of all the commercial RDTs are satisfactory for application to malaria diagnosis

    Impact and cost-effectiveness of current and future tuberculosis diagnostics: the contribution of modelling.

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    The landscape of diagnostic testing for tuberculosis (TB) is changing rapidly, and stakeholders need urgent guidance on how to develop, deploy and optimize TB diagnostics in a way that maximizes impact and makes best use of available resources. When decisions must be made with only incomplete or preliminary data available, modelling is a useful tool for providing such guidance. Following a meeting of modelers and other key stakeholders organized by the TB Modelling and Analysis Consortium, we propose a conceptual framework for positioning models of TB diagnostics. We use that framework to describe modelling priorities in four key areas: Xpert(®) MTB/RIF scale-up, target product profiles for novel assays, drug susceptibility testing to support new drug regimens, and the improvement of future TB diagnostic models. If we are to maximize the impact and cost-effectiveness of TB diagnostics, these modelling priorities should figure prominently as targets for future research

    An approach for improving the quality of country-level TB modelling.

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    Mathematical modelling is increasingly used to inform budgeting and strategic decision-making by national TB programmes. Despite the importance of these decisions, there is currently no mechanism to review and confirm the appropriateness of modelling analyses. We have developed a benchmarking, reporting, and review (BRR) approach and accompanying tools to allow constructive review of country-level TB modelling applications. This approach has been piloted in five modelling applications and the results of this study have been used to revise and finalise the approach. The BRR approach consists of 1) quantitative benchmarks against which model assumptions and results can be compared, 2) standardised reporting templates and review criteria, and 3) a multi-stage review process providing feedback to modellers during the application, as well as a summary evaluation after completion. During the pilot, use of the tools prompted important changes in the approaches taken to modelling. The pilot also identified issues beyond the scope of a review mechanism, such as a lack of empirical evidence and capacity constraints. This approach provides independent evaluation of the appropriateness of modelling decisions during the course of an application, allowing meaningful changes to be made before results are used to inform decision-making. The use of these tools can improve the quality and transparency of country-level TB modelling applications

    Dynamics of localization in a waveguide

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    This is a review of the dynamics of wave propagation through a disordered N-mode waveguide in the localized regime. The basic quantities considered are the Wigner-Smith and single-mode delay times, plus the time-dependent power spectrum of a reflected pulse. The long-time dynamics is dominated by resonant transmission over length scales much larger than the localization length. The corresponding distribution of the Wigner-Smith delay times is the Laguerre ensemble of random-matrix theory. In the power spectrum the resonances show up as a 1/t^2 tail after N^2 scattering times. In the distribution of single-mode delay times the resonances introduce a dynamic coherent backscattering effect, that provides a way to distinguish localization from absorption.Comment: 18 pages including 8 figures; minor correction

    Promoting Recovery from Substance Misuse through Engagement with Community Assets: Asset Based Community Engagement

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    © The Author(s) 2019. Evidence shows that engagement with community resources can aid the process of recovery from substance misuse, yet systematic approaches to mapping resources and building bridges to these for recovery populations are limited. If done successfully, engagement with resources that are pro-social and afford access to meaningful activities not only provides a platform for personal development, but also has the ability to trigger a social contagion of positive behaviour and improve connectedness within communities. The current paper uses Asset Based Community Development (ABCD) as the basis for an enhanced version called Asset Based Community Engagement (ABCE). The work of ABCD has been pivotal in encouraging citizen-led, strengths-based approaches to community development, yet scientific support for it remains limited. While this approach has gained much traction, it has been subject to criticism for being too optimistic and unsystematic. In response to this, the new framework, ABCE, offers a more structured approach to mapping community resources. It does however advance previous work by acknowledging the need to identify current levels of community engagement and barriers to engagement, in order to support empowerment, maximise personal capital and address barriers to engagement. Identifying barriers to engagement should not draw ABCE away from its strengths-based focus but instead, provide a platform for person-centred, holistic support to be provided to those in recovery. To support the new framework, a workbook has been developed, offering a practical output that is intended to be used by the individual in recovery alongside a member of staff within a professional service supporting the individual
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