110 research outputs found
Heterogeneous CuMn2O4, Pt, Pd and SnO2 catalysts for ambient temperature oxidation of carbon monoxide
Ambient temperature oxidation of carbon monoxide is a vital reaction for life support in enclosed
atmospheres such as submarines and spacecraft. This reaction is usually achieved through the use
of two classes of catalyst. Firstly, mixed copper and manganese oxides designated ‘Hopcalite’ or
CuMn2O4. Secondly, high surface area noble metal catalysts deposited on durable metal oxide
supports. Both of these classes of catalyst are investigated in this thesis, with the aim of
producing novel, reproducible, robust and active ambient temperature carbon monoxide
oxidation catalysts.
In this thesis, CuMn2O4 is sequentially doped and/or impregnated with low weightings (1-10%)
of the transition metals V and Ce, noble metals Pd and Pt and metalloid Si in an attempt to
improve activity and moisture resistance. It was observed that doped V, Ce, Pd and Si are
catalytic poisons toward CuMn2O4. This is likely due to their interference in the Cu ↔ Mn redox
mechanism. XRD investigations infer doped Pd is a structural promoter toward CuMn2O4,
increasing surface area and decreasing catalyst crystalinity. Impregnation of noble metals Pt and
Pd onto CuMn2O4 surface causes deactivation of the noble metals, most likely due to the
oxidation of Pt and Pd by Mn. No novel catalyst tested in this thesis displayed increased
resistance to moisture deactivation.
Noble metals Pt and Pd were impregnated upon 3 mm diameter Al2O3 spheres and tested for
ambient temperature CO oxidation activity. The positive synergy between the two metals is
measured, and the most efficient Pt:Pd ratio is discovered to be ~ 1:4.
A novel, atom efficient method, for synthesising Pt/Pd/SnO2/Al2O3 catalysts using tin oxalate
was conceived of and investigated. Compared to existing reference catalysts, oxalate derived
catalysts preformed favourably and can be described as equivalently active
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Hospice Quality, Race, and Disenrollment in Hospice Enrollees With Dementia
Background: Racial and ethnic minoritized people with dementia (PWD) are at high risk of disenrollment from hospice, yet little is known about the relationship between hospice quality and racial disparities in disenrollment among PWD. Objective: To assess the association between race and disenrollment between and within hospice quality categories in PWD. Design/Setting/Subjects: Retrospective cohort study of 100% Medicare beneficiaries 65+ enrolled in hospice with a principal diagnosis of dementia, July 2012-December 2017. Race and ethnicity (White/Black/Hispanic/Asian and Pacific Islander [AAPI]) was assessed with the Research Triangle Institute (RTI) algorithm. Hospice quality was assessed with the publicly-available Consumer Assessment of Healthcare Providers and Systems (CAHPS) survey item on overall hospice rating, including a category for hospices exempt from public reporting (unrated). Results: The sample included 673,102 PWD (mean age 86, 66% female, 85% White, 7.3% Black, 6.3% Hispanic, 1.6% AAPI) enrolled in 4371 hospices nationwide. Likelihood of disenrollment was higher in hospices in the lowest quartile of quality ratings (vs. highest quartile) for both White (adjusted odds ratio [AOR] 1.12 [95% confidence interval 1.06-1.19]) and minoritized PWD (AOR range 1.2-1.3) and was substantially higher in unrated hospices (AOR range 1.8-2.0). Within both low- and high-quality hospices, minoritized PWD were more likely to be disenrolled compared with White PWD (AOR range 1.18-1.45). Conclusions: Hospice quality predicts disenrollment, but does not fully explain disparities in disenrollment for minoritized PWD. Efforts to improve racial equity in hospice should focus both on increasing equity in access to high-quality hospices and improving care for racial minoritized PWD in all hospices
Good for your soul? Adult learning and mental well-being
Although there is a widely held view that adult learning has a positive impact on well-being, only recently has this proposition been systematically tested. The paper reviews recent research findings on the influence of adult learning on earnings and employability, both of which may influence well-being indirectly. These are more important for some groups than others: in economically advanced societies, additional earnings produce limited gains in well-being for most groups except the poorest, while employability is most significant for groups that are most vulnerable in the labour market. The author then reviews recent research findings showing that participating in learning in adult life has some positive direct influence on well-being; analyses of cohort studies suggest that the influence is comparatively small, but nevertheless significant. There has been less study of learning’s negative consequences for well-being, and the paper draws on history data to illustrate some of these less desirable influences. It concludes by identifying areas for further research, and outlining a number of implications for policy and practice. These are particularly important in the current context, where environmental movements appear to be challenging the primacy of economic growth as the overarching goal of policy
An empirical study of normative dissociation in musical and non-musical everyday life experiences
Dissociative experiences involving music have received little research attention outside the field of
ethnomusicology. This paper examines the psychological characteristics of normative dissociation
(detachment) across musical and non-musical experiences in ‘real world’, everyday settings. It draws
upon a subset of data arising from an empirical project designed to compare transformative shifts of
consciousness, with and without music in daily life, and the ways in which use of music may facilitate
the processes of dissociation and absorption. Twenty participants kept unstructured diaries for two weeks,
recording free descriptions of involving experiences of any kind as soon as possible after their occurrence.
All descriptions were subsequently subjected to Interpretative Phenomenological Analysis (IPA).
Results suggest that dissociative experiences are a familiar occurrence in everyday life. Diary
entries highlight an established practice of actively sought detachment from self, surroundings or
activity, suggesting that, together with absorption, the processes of derealization (altered perception
of surroundings) and depersonalization (detachment from self) constitute common means of selfregulation
in daily life. Music emerges as a particularly versatile facilitator of dissociative experience
because of its semantic ambiguity, portability, and the variety of ways in which it may mediate
perception, so facilitating an altered relationship to self and environmen
The Science Performance of JWST as Characterized in Commissioning
This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies
Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980–2015: a systematic analysis for the Global Burden of Disease Study 2015
Background Improving survival and extending the longevity of life for all populations requires timely, robust evidence on local mortality levels and trends. The Global Burden of Disease 2015 Study (GBD 2015) provides a comprehensive assessment of all-cause and cause-specific mortality for 249 causes in 195 countries and territories from 1980 to 2015. These results informed an in-depth investigation of observed and expected mortality patterns based on sociodemographic measures. Methods We estimated all-cause mortality by age, sex, geography, and year using an improved analytical approach originally developed for GBD 2013 and GBD 2010. Improvements included refinements to the estimation of child and adult mortality and corresponding uncertainty, parameter selection for under-5 mortality synthesis by spatiotemporal Gaussian process regression, and sibling history data processing. We also expanded the database of vital registration, survey, and census data to 14 294 geography–year datapoints. For GBD 2015, eight causes, including Ebola virus disease, were added to the previous GBD cause list for mortality. We used six modelling approaches to assess cause-specific mortality, with the Cause of Death Ensemble Model (CODEm) generating estimates for most causes. We used a series of novel analyses to systematically quantify the drivers of trends in mortality across geographies. First, we assessed observed and expected levels and trends of cause-specific mortality as they relate to the Socio-demographic Index (SDI), a summary indicator derived from measures of income per capita, educational attainment, and fertility. Second, we examined factors affecting total mortality patterns through a series of counterfactual scenarios, testing the magnitude by which population growth, population age structures, and epidemiological changes contributed to shifts in mortality. Finally, we attributed changes in life expectancy to changes in cause of death. We documented each step of the GBD 2015 estimation processes, as well as data sources, in accordance with Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER). Findings Globally, life expectancy from birth increased from 61·7 years (95% uncertainty interval 61·4–61·9) in 1980 to 71·8 years (71·5–72·2) in 2015. Several countries in sub-Saharan Africa had very large gains in life expectancy from 2005 to 2015, rebounding from an era of exceedingly high loss of life due to HIV/AIDS. At the same time, many geographies saw life expectancy stagnate or decline, particularly for men and in countries with rising mortality from war or interpersonal violence. From 2005 to 2015, male life expectancy in Syria dropped by 11·3 years (3·7–17·4), to 62·6 years (56·5–70·2). Total deaths increased by 4·1% (2·6–5·6) from 2005 to 2015, rising to 55·8 million (54·9 million to 56·6 million) in 2015, but age-standardised death rates fell by 17·0% (15·8–18·1) during this time, underscoring changes in population growth and shifts in global age structures. The result was similar for non-communicable diseases (NCDs), with total deaths from these causes increasing by 14·1% (12·6–16·0) to 39·8 million (39·2 million to 40·5 million) in 2015, whereas age-standardised rates decreased by 13·1% (11·9–14·3). Globally, this mortality pattern emerged for several NCDs, including several types of cancer, ischaemic heart disease, cirrhosis, and Alzheimer's disease and other dementias. By contrast, both total deaths and age-standardised death rates due to communicable, maternal, neonatal, and nutritional conditions significantly declined from 2005 to 2015, gains largely attributable to decreases in mortality rates due to HIV/AIDS (42·1%, 39·1–44·6), malaria (43·1%, 34·7–51·8), neonatal preterm birth complications (29·8%, 24·8–34·9), and maternal disorders (29·1%, 19·3–37·1). Progress was slower for several causes, such as lower respiratory infections and nutritional deficiencies, whereas deaths increased for others, including dengue and drug use disorders. Age-standardised death rates due to injuries significantly declined from 2005 to 2015, yet interpersonal violence and war claimed increasingly more lives in some regions, particularly in the Middle East. In 2015, rotaviral enteritis (rotavirus) was the leading cause of under-5 deaths due to diarrhoea (146 000 deaths, 118 000–183 000) and pneumococcal pneumonia was the leading cause of under-5 deaths due to lower respiratory infections (393 000 deaths, 228 000–532 000), although pathogen-specific mortality varied by region. Globally, the effects of population growth, ageing, and changes in age-standardised death rates substantially differed by cause. Our analyses on the expected associations between cause-specific mortality and SDI show the regular shifts in cause of death composition and population age structure with rising SDI. Country patterns of premature mortality (measured as years of life lost [YLLs]) and how they differ from the level expected on the basis of SDI alone revealed distinct but highly heterogeneous patterns by region and country or territory. Ischaemic heart disease, stroke, and diabetes were among the leading causes of YLLs in most regions, but in many cases, intraregional results sharply diverged for ratios of observed and expected YLLs based on SDI. Communicable, maternal, neonatal, and nutritional diseases caused the most YLLs throughout sub-Saharan Africa, with observed YLLs far exceeding expected YLLs for countries in which malaria or HIV/AIDS remained the leading causes of early death. Interpretation At the global scale, age-specific mortality has steadily improved over the past 35 years; this pattern of general progress continued in the past decade. Progress has been faster in most countries than expected on the basis of development measured by the SDI. Against this background of progress, some countries have seen falls in life expectancy, and age-standardised death rates for some causes are increasing. Despite progress in reducing age-standardised death rates, population growth and ageing mean that the number of deaths from most non-communicable causes are increasing in most countries, putting increased demands on health systems. Funding Bill & Melinda Gates Foundation
The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy
Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations.
Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves.
Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p 90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score.
Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care
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