5,090 research outputs found

    Reconstruction with velocities

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    Reconstruction is becoming a crucial procedure of galaxy clustering analysis for future spectroscopic redshift surveys to obtain subper cent level measurement of the baryon acoustic oscillation scale. Most reconstruction algorithms rely on an estimation of the displacement field from the observed galaxy distribution. However, the displacement reconstruction degrades near the survey boundary due to incomplete data and the boundary effects extend to ∼100 Mpc/h within the interior of the survey volume. We study the possibility of using radial velocities measured from the cosmic microwave background observation through the kinematic Sunyaev-Zeldovich effect to improve performance near the boundary. We find that the boundary effect can be reduced to ∼30 − 40 Mpc/h with the velocity information from Simons Observatory. This is especially helpful for dense low redshift surveys where the volume is relatively small and a large fraction of total volume is affected by the boundary

    Pattern of adult intestinal obstruction at Tenwek hospital, in south-western Kenya

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    Introduction: acute mechanical intestinal obstruction (IO) is one of the leading causes of surgical admissions in most emergency departments worldwide. The causes of IO vary significantly depending on geographical location. The aim of this study was to identify the etiology, management and outcomes of patients with acute mechanical IO presenting in south-western Kenya. Methods: a 4 year (November 2009–October 2013) retrospective review of all adult patients admitted with acute mechanical IO at Tenwek Hospital in Bomet, Kenya. Results: a total of 303 male and 142 female patients, presented with acute mechanical IO during the study period. Mean patient age was 40.6 years (range 17-91), with peak  incidence in those aged 31-40 years. The foremost signs and symptoms were abdominal pain (89.4%), abdominal tenderness (81.6%), vomiting (78%), abdominal distension (65.4%) and constipation (50.8%). Sigmoid volvulus (25.6%), adhesions (23.1%), small bowel volvulus (21.3%), and ileo-sigmoid knotting (8.5%) were the leading causes of IO. Laparotomy was undertaken in 361 (81.1%) cases, with bowel gangrene noted in 112 (30.4%). The overall morbidity and mortality rates were 15% and 4.5% respectively. Patients with gangrenous bowel at laparotomy had a higher morbidity rate (22.3% vs 9.6%, P=.001), a higher mortality rate (9.8% vs 3.2%, P=.02) and a longer duration of stay (9.9 days vs 7.6 days,  P=.0001) compared to those with viable bowel. Conclusion: the most common causes of IO in this study were sigmoid volvulus, adhesions, small bowel volvulus and ileo-sigmoid knotting. Presence of bowel gangrene was associated with higher morbidity and mortality rates

    Translating the complexities of flood risk science using KEEPER - a knowledge exchange exploratory tool for professionals in emergency response

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    Within flood risk management (FRM) decision making, there is a growing interest in participatory approaches to engage and integrate stakeholder expertise. Decision support tools are becoming common features in the FRM ‘toolkit’, yet there is a limited application of participatory methodologies in the construction of such tools. This paper reports on completed FRMRC research (Flood Risk Management Research Consortium, UK http://www.floodrisk.org.uk/) and the construction of a geographic information system-based flood risk assessment tool, KEEPER – a Knowledge Exchange Exploratory tool for Professionals in Emergency Response. An iterative methodology was used to engage emergency professionals throughout the research process, allowing a mixing of scientific and professional expertise in the co-production of KEEPER. KEEPER was both instrumental in facilitating participation and knowledge exchange, and informing recommendations for future tools in practice. This paper argues that participation is both essential for supporting pragmatic flood research and as a means of enhancing communication across traditionally divided communities

    Role of Rigid Endoscopic Detorsion in the Management of Sigmoid Volvulus

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    Introduction: Sigmoid Volvulus (SV) is a common cause of bowel obstruction in Africa, affecting a relatively young and healthy population. There has been little research regarding the use of endoscopic detorsion in the management of SV from East Africa. The aim of this study was to determine the outcome of patients with SV managed by endoscopic detorsion at a single institution over a 9 year period.Methods: A retrospective review of all patients admitted with SV at Tenwek Hospital in Bomet, Kenya from January 2006 to October 2014 was done. Data were collected on demographics, clinical presentation, operative findings, management, and outcome.Results: There were 159 cases with a mean age of 41.1 years (range 15-87). Rigid endoscopic detorsion was attempted in 125 (79%) patients. The success, early recurrence, and mortality rate for rigid endoscopic detorsion was 79%, 6%, and 0% respectively. Eleven (13%, n=99) patients declined surgery after successful endoscopic detorsion, while 87 patients had semi-elective surgery, an average of 3.5 days post detorsion. Sixty patients had emergency surgery, with gangrenous bowel noted in 43 (72%) cases. Patients undergoing emergency surgery had a higher morbidity rate (27% vs. 5%, p=0.0002), and a higher mortality rate (12% vs. 0, p=0.002) compared to those having semi-elective surgery due to the presence of gangrenous bowel.Conclusion: Rigid endoscopic detorsion is appropriate in the initial management of any stable patient with clinical and radiological features suggestive of sigmoid volvulus without features of peritonitis.Keywords: Sigmoid Volvulus, Endoscopic Detorsion, Rigid Sigmoidoscopy, Outcomes

    Weight management: a comparison of existing dietary approaches in a work-site setting

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    <b>OBJECTIVES:</b> (1) To compare the effectiveness a 2512 kJ (600 kcal) daily energy deficit diet (ED) with a 6279 kJ (1500 kcal) generalized low-calorie diet (GLC) over a 24 week period (12 weeks weight loss plus 12 weeks weight maintenance). (2) To determine if the inclusion of lean red meat at least five times per week as part of a slimming diet is compatible with weight loss in comparison with a diet that excludes lean red meat. DESIGN: Randomized controlled trial. <b>SETTING:</b> Large petrochemical work-site. <b>PARTICIPANTS:</b> One-hundred and twenty-two men aged between 18 and 55 y. <b>MAIN OUTCOME MEASURES:</b> Weight loss and maintenance of weight loss. <b>INTERVENTION:</b> Eligible volunteers were randomized to one of the four diet=meat combinations (ED meat, ED no meat, GLC meat, GLC no meat). One-third of subjects in each diet/meat combination were randomized to an initial control period prior to receiving dietary advice. All subjects attended for review every 2 weeks during the weight loss period. For the 12 week structured weight maintenance phase, individualized energy prescriptions were re-calculated for the ED group as 1.4 (activity factor)x basal metabolic rate. Healthy eating advice was reviewed with subjects in the GLC group. All subjects were contacted by electronic mail at 2 week intervals and anthropometric and dietary information requested. <b>RESULTS:</b> No difference was evident between diet groups in mean weight loss at 12 weeks (4.3 (s.d. 3.4) kg ED group vs 5.0 (s.d. 3.5) kg GLC group, P=0.34). Mean weight loss was closer to the intended weight loss in the 2512 kJ (600 kcal) ED group. The dropout rate was also lower than the GLC group. The inclusion of lean red meat in the diet on at least five occasions per week did not impair weight loss. Mean weight gain following 12 weeks weight maintenance was þ1.1 (s.d. 1.8) kg, P<0.0001. No differences were found between groups. <b>CONCLUSIONS:</b> This study has shown that the individualized 2512 kJ (600 kcal) ED approach was no more effective in terms of weight loss than the 6279 kJ (1500 kcal) GLC approach. However the ED approach might be considered preferable as compliance was better with this less demanding prescription. In terms of weight loss the elimination of red meat from the diet is unnecessary. The weight maintenance intervention was designed as a low-input approach, however weight regain was significant and weight maintenance strategies require further development

    Spectrum, risk factors and outcomes of neurological and psychiatric complications of COVID-19: a UK-wide cross-sectional surveillance study

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    SARS-CoV-2 is associated with new-onset neurological and psychiatric conditions. Detailed clinical data, including factors associated with recovery, are lacking, hampering prediction modelling and targeted therapeutic interventions. In a UK-wide cross-sectional surveillance study of adult hospitalized patients during the first COVID-19 wave, with multi-professional input from general and sub-specialty neurologists, psychiatrists, stroke physicians, and intensivists, we captured detailed data on demographics, risk factors, pre-COVID-19 Rockwood frailty score, comorbidities, neurological presentation and outcome. A priori clinical case definitions were used, with cross-specialty independent adjudication for discrepant cases. Multivariable logistic regression was performed using demographic and clinical variables, to determine the factors associated with outcome. A total of 267 cases were included. Cerebrovascular events were most frequently reported (131, 49%), followed by other central disorders (95, 36%) including delirium (28, 11%), central inflammatory (25, 9%), psychiatric (25, 9%), and other encephalopathies (17, 7%), including a severe encephalopathy (n = 13) not meeting delirium criteria; and peripheral nerve disorders (41, 15%). Those with the severe encephalopathy, in comparison to delirium, were younger, had higher rates of admission to intensive care and a longer duration of ventilation. Compared to normative data during the equivalent time period prior to the pandemic, cases of stroke in association with COVID-19 were younger and had a greater number of conventional, modifiable cerebrovascular risk factors. Twenty-seven per cent of strokes occurred in patients 60 years old, the younger stroke patients presented with delayed onset from respiratory symptoms, higher rates of multi-vessel occlusion (31%) and systemic thrombotic events. Clinical outcomes varied between disease groups, with cerebrovascular disease conferring the worst prognosis, but this effect was less marked than the pre-morbid factors of older age and a higher pre-COVID-19 frailty score, and a high admission white cell count, which were independently associated with a poor outcome. In summary, this study describes the spectrum of neurological and psychiatric conditions associated with COVID-19. In addition, we identify a severe COVID-19 encephalopathy atypical for delirium, and a phenotype of COVID-19 associated stroke in younger adults with a tendency for multiple infarcts and systemic thromboses. These clinical data will be useful to inform mechanistic studies and stratification of patients in clinical trials

    On the ability of spectroscopic SZ effect measurements to determine the temperature structure of galaxy clusters

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    (abridged) We explore in this paper the ability of spatially resolved spectroscopic measurements of the SZ effect (SZE) to determine the temperature profile of galaxy clusters. We derive a general formalism for the thermal SZE in galaxy clusters with a non-uniform temperature profile that can be applied to both cool-core clusters and non-cool core cluster with an isothermal or non-isothermal temperature structure. We derive an inversion technique through which the electron distribution function can be extracted from spectroscopic SZE observations over a wide frequency range. We study the fitting procedure to extract the cluster temperature from a set of simulated spatially resolved spectroscopic SZE observations in different bands of the spectrum, from 100 to 450 GHz. The results of our analysis for three different cluster prototypes (A2199 with a low-temperature cool core, Perseus with a relatively high-temperature cool core, Ophiuchus with an isothermal temperature distribution) provide both the required precision of the SZE observations and the optimal frequency bands for a determination of the cluster temperature similar or better than that obtainable from X-ray observations. The precision of SZE-derived temperature is also discussed for the outer regions of clusters. We also study the possibility to extract, from our method, the parameters characterizing the non-thermal SZE spectrum of the relativistic plasma contained in the lobes of radio galaxies as well as the spectrum of relativistic electrons co-spatially distributed with the thermal plasma in clusters with non-thermal phenomena. We find that the next generation SZE experiments with spectroscopic capabilities can provide precise temperature distribution measurements (...)Comment: Submitted to Astronomy & Astrophysic

    Quantitative measure of evolution of bright cluster galaxies at moderate redshifts

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    Using archival data from the Hubble Space Telescope, we study the quantitative morphological evolution of spectroscopically confirmed bright galaxies in the core regions of nine clusters ranging in redshift from z=0.31z = 0.31 to z=0.84z = 0.84. We use morphological parameters derived from two dimensional bulge-disk decomposition to study the evolution. We find an increase in the mean bulge-to-total luminosity ratio B/TB/T as the Universe evolves. We also find a corresponding increase in the fraction of early type galaxies and in the mean S\'ersic index. We discuss these results and their implications to physical mechanisms for evolution of galaxy morphology.Comment: 5 pages, 3 figures, Accepted for publication in MNRAS: Letter

    The JCMT Legacy Survey of the Gould Belt: Mapping 13CO and C 18O in Orion A

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    The Gould Belt Legacy Survey will map star-forming regions within 500 pc, using Heterodyne Array Receiver Programme (HARP), Submillimetre Common-User Bolometer Array 2 (SCUBA-2) and Polarimeter 2 (POL-2) on the James Clerk Maxwell Telescope (JCMT). This paper describes HARP observations of the J= 3 → 2 transitions of 13CO and C18O towards Orion A. The 15 arcsec resolution observations cover 5 pc of the Orion filament, including OMC 1 (including BN–KL and Orion bar), OMC 2/3 and OMC 4, and allow a comparative study of the molecular gas properties throughout the star-forming cloud. The filament shows a velocity gradient of ∼1 km s−1 pc−1 between OMC 1, 2 and 3, and high-velocity emission is detected in both isotopologues. The Orion Nebula and Bar have the largest masses and linewidths, and dominate the mass and energetics of the high-velocity material. Compact, spatially resolved emission from CH3CN, 13CH3OH, SO, HCOOCH3, CH3CHO and CH3OCHO is detected towards the Orion Hot Core. The cloud is warm, with a median excitation temperature of ∼24 K; the Orion Bar has the highest excitation temperature gas, at >80 K. The C18O excitation temperature correlates well with the dust temperature (to within 40 per cent). The C18O emission is optically thin, and the 13CO emission is marginally optically thick; despite its high mass, OMC 1 shows the lowest opacities. A virial analysis indicates that Orion A is too massive for thermal or turbulent support, but is consistent with a model of a filamentary cloud that is threaded by helical magnetic fields. The variation of physical conditions across the cloud is reflected in the physical characteristics of the dust cores. We find similar core properties between starless and protostellar cores, but variations in core properties with position in the filament. The OMC 1 cores have the highest velocity dispersions and masses, followed by OMC 2/3 and OMC 4. The differing fragmentation of these cores may explain why OMC 1 has formed clusters of high-mass stars, whereas OMC 4 produces fewer, predominantly low-mass stars
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