1,796 research outputs found

    On the relative roles of dynamics and chemistry governing the abundance and diurnal variation of low latitude thermospheric nitric oxide

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    We use data from two NASA satellites, the Thermosphere Ionosphere Energetics and Dynamics (TIMED) and the Aeronomy of Ice in the Mesosphere (AIM) satellites in conjunction with model simulations from the Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM) to elucidate the key dynamical and chemical factors governing the abundance and diurnal variation of nitric oxide (NO) at near solar minimum conditions and low latitudes. This analysis was enabled by the recent orbital precession of the AIM satellite which caused the solar occultation pattern measured by the Solar Occultation for Ice Experiment (SOFIE) to migrate down to low and mid latitudes for specific periods of time. We use a month of NO data collected in January 2017 to compare with two versions of the TIME-GCM, one driven solely by climatological tides and analysis-derived planetary waves at the lower boundary and free running at all other altitudes, while the other is constrained by a high-altitude analysis from the Navy Global Environmental Model (NAVGEM)up to the mesopause. We also compare SOFIE data with a NO climatology from the Nitric Oxide Empirical Model (NOEM). Both SOFIE and NOEM yield peak NO abundances of around 4×107cm−3; however, the SOFIE profile peaks about 6-8 km lower than NOEM. We show that this difference is likely a local time effect; SOFIE being a dawn measurement and NOEM representing late morning/near noon. The constrained version of TIME-GCM exhibits a low altitude dawn peak while the model that is forced solely at the lower boundary and free running above does not. We attribute this difference due to a phase change in the semi-diurnal tide in the NAVGEM-constrained model causing descent of high NO mixing ratio air near dawn. This phase difference between the two models arises due to differences in the mesospheric zonal mean zonal winds. Regarding the absolute NO abundance, all versions of the TIME-GCM overestimate this. Tuning the model to yield calculated atomic oxygen in agreement with TIMED data helps, but is insufficient. Further, the TIME-GCM underestimates the electron density [e-] as compared with the International Reference Ionosphere empirical model. This suggests a potential conflict with the requirements of NO modeling and [e-] modeling since one solution typically used to increase model [e-] is to increase the solar soft X ray flux which would, in this case, worsen the NO model/data discrepancy

    Alcohol and cocaine use prior to suspected suicide: Insights from toxicology

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    Introduction This study investigates whether there is a relationship between alcohol and cocaine use in deaths where suicide by self-injury is the suspected cause of death. Methods Adults referred by coroners to the Imperial College London Toxicology Unit for toxicological analysis between 2012 and 2016 were reviewed for inclusion criteria. Those who died by self-injury reasoned to be deliberate were included in the analysis. Femoral blood alcohol concentration (BAC) and presence of cocaine or benzoylecognine (a metabolite of cocaine) in blood and/or urine were tabulated and odds ratios calculated. Results A total of 1722 decedents met inclusion criteria. BAC was ≥50 mg/dL in 29% of decedents. Cocaine was detected in 8.4% of cases. The likelihood of testing positive for cocaine increased with BAC and was most frequent between 100 and 199 mg/dL, consistent with moderate to severe intoxication (odds ratio 5.88, 95% confidence interval 3.80, 9.09; P ≤ 0.001) compared to those with BAC <10 mg/dL. Discussion and Conclusions This study demonstrates a correlation between increasing BAC and likelihood of cocaine use prior to suspected suicide, up to a level consistent with severe intoxication. Cocaine use was found in a high proportion of cases relative to the general population reporting regular use. This pattern of drug and alcohol use has previously been given little attention in suicide prevention strategies and clinical prioritisation

    Risk factors for race-day fatality in flat racing Thoroughbreds in Great Britain (2000 to 2013)

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    A key focus of the racing industry is to reduce the number of race-day events where horses die suddenly or are euthanased due to catastrophic injury. The objective of this study was therefore to determine risk factors for race-day fatalities in Thoroughbred racehorses, using a cohort of all horses participating in flat racing in Great Britain between 2000 and 2013. Horse-, race- and course-level data were collected and combined with all race-day fatalities, recorded by racecourse veterinarians in a central database. Associations between exposure variables and fatality were assessed using logistic regression analyses for (1) all starts in the dataset and (2) starts made on turf surfaces only. There were 806,764 starts in total, of which 548,571 were on turf surfaces. A total of 610 fatalities were recorded; 377 (61.8%) on turf. In both regression models, increased firmness of the going, increasing racing distance, increasing average horse performance, first year of racing and wearing eye cover for the first time all increased the odds of fatality. Generally, the odds of fatality also increased with increasing horse age whereas increasing number of previous starts reduced fatality odds. In the ‘all starts’ model, horses racing in an auction race were at 1.46 (95% confidence interval (CI) 1.06–2.01) times the odds of fatality compared with horses not racing in this race type. In the turf starts model, horses racing in Group 1 races were at 3.19 (95% CI 1.71–5.93) times the odds of fatality compared with horses not racing in this race type. Identification of novel risk factors including wearing eye cover and race type will help to inform strategies to further reduce the rate of fatality in flat racing horses, enhancing horse and jockey welfare and safety

    Impacts and environmental risks of oil spills on marine invertebrates, algae and seagrass: a global review from an Australian perspective

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    Marine invertebrates and macrophytes are sensitive to the toxic effects of oil. Depending on the intensity, duration and circumstances of the exposure, they can suffer high levels of initial mortality together with prolonged sublethal effects that can act at individual, population and community levels. Under some circumstances, recovery from these impacts can take years to decades. However, effects are variable because some taxa are less sensitive than others, and many factors can mitigate the degree of exposure, meaning that impacts are moderate in many cases, and recovery occurs within a few years. Exposure is affected by a myriad of factors including: Type and amount of oil, extent of weathering, persistence of exposure, application of dispersants or other clean-up measures, habitat type, temperature and depth, species present and their stage of development or maturity, and processes of recolonisation, particularly recruitment. Almost every oil spill is unique in terms of its impact because of differing levels of exposure and the type of habitats, communities and species assemblages in the receiving environment. Between 1970 and February 2017, there were 51 significant oil spills in Australia. Five occurred offshore with negligible likely or expected impacts. Of the others, only 24 of the spills were studied in detail, while 19 had only cursory or no assessment despite the potential for oil spills to impact the marine environment. The majority were limited to temperate waters, although 10 of the 14 spills since 2000 were in tropical coastal or offshore areas, seven were in north Queensland in areas close to the Great Barrier Reef. All four spills that have occurred from offshore petroleum industry infrastructure have occurred since 2009. In Australia, as elsewhere, a prespill need exists to assess the risk of a spill, establish environmental baselines, determine the likely exposure of the receiving environment, and test the toxicity of the oil against key animal and plant species in the area of potential impact. Subsequent to any spill, the baseline provides a reference for targeted impact monitoring

    The Red Sea, Coastal Landscapes, and Hominin Dispersals

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    This chapter provides a critical assessment of environment, landscape and resources in the Red Sea region over the past five million years in relation to archaeological evidence of hominin settlement, and of current hypotheses about the role of the region as a pathway or obstacle to population dispersals between Africa and Asia and the possible significance of coastal colonization. The discussion assesses the impact of factors such as topography and the distribution of resources on land and on the seacoast, taking account of geographical variation and changes in geology, sea levels and palaeoclimate. The merits of northern and southern routes of movement at either end of the Red Sea are compared. All the evidence indicates that there has been no land connection at the southern end since the beginning of the Pliocene period, but that short sea crossings would have been possible at lowest sea-level stands with little or no technical aids. More important than the possibilities of crossing the southern channel is the nature of the resources available in the adjacent coastal zones. There were many climatic episodes wetter than today, and during these periods water draining from the Arabian escarpment provided productive conditions for large mammals and human populations in coastal regions and eastwards into the desert. During drier episodes the coastal region would have provided important refugia both in upland areas and on the emerged shelves exposed by lowered sea level, especially in the southern sector and on both sides of the Red Sea. Marine resources may have offered an added advantage in coastal areas, but evidence for their exploitation is very limited, and their role has been over-exaggerated in hypotheses of coastal colonization

    Combined adenocarcinoid and mucinous cystadenoma of the appendix: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Adenocarcinoid of the appendix is a rare malignant tumour with features of both adenocarcinoma and carcinoid, showing both epithelial and endocrine differentiation. Mucinous cystadenoma is the commonest of the benign neoplasms of the appendix, with an incidence of 0.6% in appendicectomy specimens. We report a rare combination of these tumours and discuss the latest treatment options. To the best of our knowledge, only six cases have been reported in the literature to date.</p> <p>Case presentation</p> <p>A 71-year-old Caucasian man presented to our department with a right iliac fossa mass associated with pain. Laparoscopy revealed an adenocarcinoid of the appendix in combination with mucinous cystadenoma. He underwent a radical right hemicolectomy with clear margins and lymph nodes.</p> <p>Conclusion</p> <p>Adenocarcinoids account for 2% of primary appendiceal malignancies. Most tumours are less than 2 cm in diameter and 20% of them metastasize to the ovaries. The mean age for presentation is 59 years and the 5-year survival rate ranges from 60% to 84%. Right hemicolectomy is generally advised if any of the following features are present: tumours greater than 2 cm, involvement of resection margins, greater than 2 mitoses/10 high-power fields on histology, extension of tumour beyond serosa. Chemotherapy mostly with 5-Fluorouracil and Leucovorin is advised for remnant disease after surgery. Cytoreductive surgery with intraperitoneal chemotherapy can offer improved survival for advanced peritoneal dissemination.</p

    A prolonged run-in period of standard subcutaneous microdialysis ameliorates quality of interstitial glucose signal in patients after major cardiac surgery

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    We evaluated a standard subcutaneous microdialysis technique for glucose monitoring in two critically ill patient populations and tested whether a prolonged run-in period improves the quality of the interstitial glucose signal. 20 surgical patients after major cardiac surgery (APACHE II score: 10.1 ± 3.2) and 10 medical patients with severe sepsis (APACHE II score: 31.1 ± 4.3) were included in this investigation. A microdialysis catheter was inserted in the subcutaneous adipose tissue of the abdominal region. Interstitial fluid and arterial blood were sampled in hourly intervals to analyse glucose concentrations. Subcutaneous adipose tissue glucose was prospectively calibrated to reference arterial blood either at hour 1 or at hour 6. Median absolute relative difference of glucose (MARD), calibrated at hour 6 (6.2 (2.6; 12.4) %) versus hour 1 (9.9 (4.2; 17.9) %) after catheter insertion indicated a significant improvement in signal quality in patients after major cardiac surgery (p < 0.001). Prolonged run-in period revealed no significant improvement in patients with severe sepsis, but the number of extreme deviations from the blood plasma values could be reduced. Improved concurrence of glucose readings via a 6-hour run-in period could only be achieved in patients after major cardiac surgery

    Framing Male Circumcision to Promote its Adoption in Different Settings

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    The effectiveness of male circumcision in preventing transmission of HIV from females to males has been established. Those who are now advocating its widespread use face many challenges in convincing policy-makers and the public of circumcision’s value. We suggest that frames are a useful lens for communicating public health messages that may help promote adoption of circumcision. Frames relate to how individuals and societies perceive and understand the world. Existing frames are often hard to shift, and should be borne in mind by advocates and program implementers as they attempt to promote male circumcision by invoking new frames. Frames differ across and within societies, and advocates must find ways of delivering resonant messages that take into account prior perceptions and use the most appropriate means of communicating the benefits and value of male circumcision to different audiences
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