476 research outputs found

    Meteoroid bumper experiment on Explorer 46

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    The effectiveness of a meteoroid bumper in reducing meteoroid penetrations is discussed. The bumper reduced the penetration flux by a factor of 30 and demonstrated a weight savings of a factor of 6.9 in the material needed to resist meteoroid penetration. The method of calculating the penetration flux recommended in the NASA space vehicle design criteria for meteoroid damage assessment was found to be very conservative, and changes are suggested. The optimum distribution of material between a bumper and the main wall is discussed

    Enabling lunar and space missions by laser power transmission

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    Applications are proposed for laser power transmission on the Moon. A solar-pumped laser in lunar orbit would beam power to the lunar surface for conversion into either electricity or propulsion needs. For example, lunar rovers could be much more flexible and lighter than rovers using other primary power sources. Also, laser power could be absorbed by lunar soil to create a hard glassy surface for dust-free roadways and launch pads. Laser power could also be used to power small lunar rockets or orbital transfer vehicles, and finally, photovoltaic laser converters could power remote excavation vehicles and human habitats. Laser power transmission is shown to be a highly flexible, enabling primary power source for lunar missions

    Lunar Lava Tube Radiation Safety Analysis

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    For many years it has been suggested that lava tubes on the Moon could provide an ideal location for a manned lunar base, by providing shelter from various natural hazards, such as cosmic radiation, meteorites, micrometeoroids, and impact crater ejecta, and also providing a natural environmental control, with a nearly constant temperature, unlike that of the lunar surface showing extreme variation in its diurnal cycle. An analysis of radiation safety issues on lunar lava tubes has been performed by considering radiation from galactic cosmic rays (GCR) and Solar Particle Events (SPE) interacting with the lunar surface, modeled as a regolith layer and rock. The chemical composition has been chosen as typical of the lunar re-ions where the largest number of lava tube candidates are found. Particles have been transported all through the regolith and the rock, and received particles flux and doses have been calculated. The radiation safety of lunar lava tubes environments has been demonstrated

    Translation of immunomodulatory therapy to treat chronic heart failure: Preclinical studies to first in human

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    BACKGROUND: Inflammation has been associated with progression and complications of chronic heart failure (HF) but no effective therapy has yet been identified to treat this dysregulated immunologic state. The selective cytopheretic device (SCD) provides extracorporeal autologous cell processing to lessen the burden of inflammatory activity of circulating leukocytes of the innate immunologic system. AIM: The objective of this study was to evaluate the effects of the SCD as an extracorporeal immunomodulatory device on the immune dysregulated state of HF. HF. METHODS AND RESULTS: SCD treatment in a canine model of systolic HF or HF with reduced ejection fraction (HFrEF) diminished leukocyte inflammatory activity and enhanced cardiac performance as measured by left ventricular (LV) ejection fraction and stroke volume (SV) up to 4 weeks after treatment initiation. Translation of these observations in first in human, proof of concept clinical study was evaluated in a patient with severe HFrEFHFrEF ineligible for cardiac transplantation or LV LV assist device (LVAD) due to renal insufficiency and right ventricular dysfunction. Six hour SCD treatments over 6 consecutive days resulted in selective removal of inflammatory neutrophils and monocytes and reduction in key plasma cytokines, including tumor necrosis factor-alpha (TNF-α),), interleukin (IL)-6, IL-8, and monocyte chemoattractant protein (MCP)-1. These immunologic changes were associated with significant improvements in cardiac power output, right ventricular stroke work index, cardiac index and LVSV index…. Stabilization of renal function with progressive volume removal permitted successful LVAD implantation. CONCLUSION: This translational research study demonstrates a promising immunomodulatory approach to improve cardiac performance in HFrEFHFrEF and supports the important role of inflammation in the progression of HFHF

    A systematic review of studies measuring and reporting hearing aid usage in older adults since 1999: a descriptive summary of measurement tools

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    Objective: A systematic review was conducted to identify and quality assess how studies published since 1999 have measured and reported the usage of hearing aids in older adults. The relationship between usage and other dimensions of hearing aid outcome, age and hearing loss are summarised. Data sources: Articles were identified through systematic searches in PubMed/MEDLINE, The University of Nottingham Online Catalogue, Web of Science and through reference checking. Study eligibility criteria: (1) participants aged fifty years or over with sensori-neural hearing loss, (2) provision of an air conduction hearing aid, (3) inclusion of hearing aid usage measure(s) and (4) published between 1999 and 2011. Results: Of the initial 1933 papers obtained from the searches, a total of 64 were found eligible for review and were quality assessed on six dimensions: study design, choice of outcome instruments, level of reporting (usage, age, and audiometry) and cross validation of usage measures. Five papers were rated as being of high quality (scoring 10–12), 35 papers were rated as being of moderate quality (scoring 7–9), 22 as low quality (scoring 4–6) and two as very low quality (scoring 0–2). Fifteen different methods were identified for assessing the usage of hearing aids. Conclusions: Generally, the usage data reviewed was not well specified. There was a lack of consistency and robustness in the way that usage of hearing aids was assessed and categorised. There is a need for more standardised level of reporting of hearing aid usage data to further understand the relationship between usage and hearing aid outcomes

    Duration and magnitude of postoperative risk of venous thromboembolism after planned inguinal hernia repair in men: a population-based cohort study

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    Purpose Little is known regarding the magnitude and timing of the risk of VTE following inguinal hernia surgery. We aimed to determine the absolute and relative rates of venous thromboembolism (VTE) following planned inguinal hernia repair. Methods We analysed male adults with a first inguinal hernia repair with no prior record of VTE from the Clinical Practice Research Datalink, linked to the Hospital Episode Statistics (2001–2011). Crude rates and adjusted hazard ratios (HR) of the first VTE were calculated using Cox regression analysis to compare specific time periods following the surgery compared to the general population. Results We identified 28,782 men who underwent an inguinal hernia repair with 53 (0.18%) having a first VTE in the 90 days following surgery. The overall rate of VTE in the first 90 days following surgery was 7.61 per 1000 person years (pyrs) (95% CI 5.82–9.96). Increasing age, a body mass index > 30 kg/m2 and an in-patient procedure were associated with an increased risk of VTE, when compared to the general population. The risk of VTE was highest in the 1st month following the surgery with a 2.3- (aHR 2.33; 95% CI 1.09–4.99) and 3.5- (aHR 3.47; 95% CI 2.07–5.83) fold increased risk compared to the general population for both day case and planned in-patient procedures, respectively. Conclusions Reassuringly, the absolute rates of VTE following inguinal hernia repair are low. Patients should be informed that their peak risk of VTE is during the 1st month following the surgery. Further studies on the optimum duration of thromboprophylaxis following surgery are required in high-risk patients undergoing hernia repair

    Four years of Ulysses dust data: 1996 to 1999

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    The Ulysses spacecraft is orbiting the Sun on a highly inclined ellipse (i=79 i = 79^{\circ}, perihelion distance 1.3 AU, aphelion distance 5.4 AU). Between January 1996 and December 1999 the spacecraft was beyond 3 AU from the Sun and crossed the ecliptic plane at aphelion in May 1998. In this four-year period 218 dust impacts were recorded with the dust detector on board. We publish and analyse the complete data set of both raw and reduced data for particles with masses 1016g\rm 10^{-16} g to 108\rm 10^{-8} g. Together with 1477 dust impacts recorded between launch of Ulysses and the end of 1995 published earlier \cite{gruen1995c,krueger1999b}, a data set of 1695 dust impacts detected with the Ulysses sensor between October 1990 and December 1999 is now available. The impact rate measured between 1996 and 1999 was relatively constant with about 0.2 impacts per day. The impact direction of the majority of the impacts is compatible with particles of interstellar origin, the rest are most likely interplanetary particles. The observed impact rate is compared with a model for the flux of interstellar dust particles. The flux of particles several micrometers in size is compared with the measurements of the dust instruments on board Pioneer 10 and Pioneer 11 beyond 3 AU (Humes 1980, JGR, 85, 5841--5852, 1980). Between 3 and 5 AU, Pioneer results predict that Ulysses should have seen five times more (10μm\rm \sim 10 \mu m sized) particles than actually detected.Comment: accepted by Planetary and Space Science, 22 pages, 8 figures (1 colour figure

    The development of Scotland’s Curriculum for Excellence: Amnesia and Déjà Vu

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    Scotland’s new Curriculum for Excellence (CfE) has been widely acknowledged as the most significant educational development in a generation, with the potential to transform learning and teaching in Scottish schools. In common with recent developments elsewhere, CfE seeks to re-engage teachers with processes of curriculum development, to place learning at the heart of the curriculum and to change engrained practices of schooling. This article draws upon well-established curriculum theory (notably the work of both Lawrence Stenhouse and A.V. Kelly) to analyse the new curriculum. We argue that by neglecting to take account of such theory, the curricular offering proposed by CfE is subject to a number of significant structural contradictions which may affect the impact that it ultimately exerts on learning and teaching; in effect, by ignoring the lessons of the past, CfE runs the risk of undermining the potential for real change

    “Low FIT” Colorectal Cancer: A four-year comparison of the Nottingham “4F” protocol with FIT10 in symptomatic patients.

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    Aim:To evaluate colorectal cancer outcomes after “low” (sub-threshold) Faecal Immunochemical Test (FIT) results in symptomatic patients tested in primary care.Method:Retrospective audit of 35,289 patients with FIT results, having consulted their general practitioner with lower gastrointestinal symptoms, and subsequent colorectal cancer (CRC) diagnoses. The Rapid Colorectal Cancer Diagnosis pathway was introduced in November 2017 to allow incorporation of FIT into clinical practice. The local “4F” protocol combined FIT results with blood tests and digital rectal examination (DRE): FIT, Full blood count (FBC), Ferritin and Finger.Outcome: Detection rates of CRC, missed CRC and time to diagnosis in local “4F” protocols for patients with a sub-threshold faecal Haemoglobin (fHb) result compared to thresholds of 10 and 20µgHb/g Faeces.Results:A single threshold of 10 µgHb/g Faeces identifies a population in whom the risk of CRC is 0.2% but would have missed 63 (10.5%) of 599 CRCs in this population. The Nottingham “4F” protocol would have missed fewer CRCs (42 of 599 (7%)) despite using a threshold of 20 µgHb/g Faeces for patients with normal blood tests. Subthreshold FIT results in patients subsequently diagnosed with a palpable rectal tumour yielded the longest delays.Conclusion:Combination of FIT with blood results and DRE (“4F”) reduced the risk of missed or delayed diagnosis. Further studies on the impact of such protocols on the diagnostic accuracy of FIT are expected. The value of adding blood tests to FIT may be restricted to specific parts of the fHb result spectrum
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