91 research outputs found

    WELL INTEGRITY ASSURANCE IN EOR INJECTION WELLS THROUGH THE LENS OF THERMAL PROPERTIES OF PORTLAND CEMENT

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    Heavy oil production is one of the challenges faced by the Oil and Gas industry today with reserves of trillions of barrels. When considering production, heavy oil viscosity must be reduced to gain mobility and have oil flowing. Between all possible techniques, stearn stimulation is the most promising. Steam stimulation is one of the viable methods to exmct heavy oil from oil sand reservoirs. In this thermal pnocess, steam is injected through the well down to the reservoir to warm it up to 320oC hence, subjecting the well to high temperatures. These injectants are pumped from the surface at very high temperatures and pressures and are required to enter the targeted zone with minimal amount of heat loss to the surrounding formation. The cement sheath in steam injection wells are required to have good thermal insulation properties to minimise the amount of heat loss to the formation while ensuring the integfity and flow assurance of the well. This research focuses on the thermal conductivity of cement and how the stmctural properties of cement affect heat transfer from the casing to the surmunding formation. Cement samples cured at varying temperatures are analysed using a Micro Focus X-Ray Computerised Tomography (CT) System thus, allowing the mapping of porcs and microfractures within the internal cement structur€. Cement cured at elevated temperatures show significant differences in microstructure compared to baseline samples. The thermal conductivity (k-values) of the samples are then measured and correlated to the pore distribution and curing temperahres. This will allow for thc modelling of heat flow from the casing to the zurrounding formatio

    Maternal 'near miss' collection at an Australian tertiary maternity hospital

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    Background: Australia has a maternal mortality ratio of 6.8/100000 live births, a rate akin to other developed countries and consistent with the high level care provided within the Australian health care system. With maternal mortality at very low levels assessment of severe maternal morbidity is increasingly being used as an indicator of quality of care and to identify areas for improvement in maternity services. The WHO maternal 'near miss' criteria is a standardised tool has been increasingly used worldwide to assess maternal morbidity and standards of maternity care. The aim of this study was to determine the rate and aetiology of maternal 'near misses' at King Edward Memorial Hospital (KEMH) using the WHO near miss criteria. Methods: Cases of maternal 'near miss' were prospectively identified at KEMH using the WHO near miss criteria over a period of 6 months (1st December 2014 to 31st May 2015). A descriptive analysis of the results was undertaken. Results: During the study there were 2773 live births with 19 women who had 'near miss' presentations. There were no maternal deaths. The maternal 'near miss' index rate was 7/1000 live births. The main causes of obstetric 'near miss' were obstetric haemorrhage, pre-eclampsia and early pregnancy complications. Conclusion: The rate of maternal 'near miss' at KEMH was 7/1000 live births and post-partum haemorrhage was identified as the most common aetiology, consistent with other studies in developed countries. Further research comparing currently utilised local, state and national morbidity systems would allow further validation of the WHO near miss criteria in Australian settings

    Causal attributions, lifestyle change and coronary heart disease: illness beliefs of patients of South Asian and European origin living in the UK

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    OBJECTIVE We examined and compared the illness beliefs of South Asian and European patients with coronary heart disease (CHD) about causal attributions and lifestyle change. METHODS This was a qualitative study that used framework analysis to examine in-depth interviews. SAMPLE The study comprised 65 subjects (20 Pakistani-Muslim, 13 Indian-Hindu, 12 Indian-Sikh, and 20 Europeans) admitted to one of three UK sites within the previous year with unstable angina or myocardial infarction, or to undergo coronary artery bypass surgery. RESULTS Beliefs about CHD cause varied considerably. Pakistani-Muslim participants were the least likely to report that they knew what had caused their CHD. Stress and lifestyle factors were the most frequently cited causes for CHD irrespective of ethnic grouping, although family history was frequently cited by older European participants. South Asian patients were more likely to stop smoking than their European counterparts but less likely to use audiotape stress-relaxation techniques. South Asian patients found it particularly difficult to make dietary changes. Some female South Asians developed innovative indoor exercise regimens to overcome obstacles to regular exercise. CONCLUSION Misconceptions about the cause of CHD and a lack of understanding about appropriate lifestyle changes were evident across ethnic groups in this study. The provision of information and advice relating to cardiac rehabilitation must be better tailored to the context of the specific needs, beliefs, and circumstances of patients with CHD, regardless of their ethnicity

    Mutual interference reduces offspring production in a brood- guarding bethylid wasp

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    Parasitoids have the potential to suppress populations of their hosts and thus may play an 2 important role in influencing the temporal and spatial dynamics of pest arthropods. 3 Behavioural interactions between foraging females, collectively constituting ‘mutual 4 interference’, can reduce host suppression. We use laboratory microcosms to assess the 5 prevalence and consequences of mutual interference behaviour in a bethylid wasp, Goniozus 6 nephantidis (Muesebeck) (Hymenoptera: Bethylidae), which is known to brood guard and to 7 engage in agonistic contests for individual hosts and which is also an agent of biological pest 8 control. We hold host and parasitoid numbers constant and vary the degree of female-female 9 contact that can occur. Mutual interference is manifest in a considerable reduction in the 10 number of offspring produced when females are not fully isolated from each other, due to 11 effects operating at the early stages of offspring production. This mutual interference may 12 contribute towards the limited degree of host population suppression achieved when some 13 species of bethylids are deployed as agents of biological pest control and also has clear 14 potential to influence the efficiency of mass rearing of parasitoids prior to field release

    Spatial analysis of air pollution and childhood asthma in Hamilton, Canada: comparing exposure methods in sensitive subgroups

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    <p>Abstract</p> <p>Background</p> <p>Variations in air pollution exposure within a community may be associated with asthma prevalence. However, studies conducted to date have produced inconsistent results, possibly due to errors in measurement of the exposures.</p> <p>Methods</p> <p>A standardized asthma survey was administered to children in grades one and eight in Hamilton, Canada, in 1994–95 (N ~1467). Exposure to air pollution was estimated in four ways: (1) distance from roadways; (2) interpolated surfaces for ozone, sulfur dioxide, particulate matter and nitrous oxides from seven to nine governmental monitoring stations; (3) a kriged nitrogen dioxide (NO<sub>2</sub>) surface based on a network of 100 passive NO<sub>2 </sub>monitors; and (4) a land use regression (LUR) model derived from the same monitoring network. Logistic regressions were used to test associations between asthma and air pollution, controlling for variables including neighbourhood income, dwelling value, state of housing, a deprivation index and smoking.</p> <p>Results</p> <p>There were no significant associations between any of the exposure estimates and asthma in the whole population, but large effects were detected the subgroup of children without hayfever (predominately in girls). The most robust effects were observed for the association of asthma without hayfever and NO<sub>2</sub>LUR OR = 1.86 (95%CI, 1.59–2.16) in all girls and OR = 2.98 (95%CI, 0.98–9.06) for older girls, over an interquartile range increase and controlling for confounders.</p> <p>Conclusion</p> <p>Our findings indicate that traffic-related pollutants, such as NO<sub>2</sub>, are associated with asthma without overt evidence of other atopic disorders among female children living in a medium-sized Canadian city. The effects were sensitive to the method of exposure estimation. More refined exposure models produced the most robust associations.</p

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030
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