This paper documents a major shift in market microstructure during the period 1990 through 1999. In particular, a dramatic change in the pattern of cash flows by individual and institutional investors is documented. The question becomes, what effect this change has on day-of-the-week return patterns for the Dow Jones Industrial Average, Standard and Poor's 500 index, and Standard and Poor's 500 index futures. I find Monday's return pattern has changed in the decade of the 1990's. Not only is Monday's mean return significantly large and positive for all indices, the entire anomalous pattern occurs from Monday's open to Monday's close - an intraday effect. In addition, I find evidence that trading volume is a factor in explaining the anomalous behaviour of Monday's returns. New York Stock Exchange trading volume is significantly lower on Mondays from the trading volume of other days of the week but the trading activity of individual investors is significantly higher. More recently, individual investors have increased their buying activity on Mondays relative to prior periods. Finally, Monday exhibits the largest returns in the first two trading hours when the Dow Jones Industrial Average returns are decomposed into hourly returns. The research emphasizes the dynamic nature of the time series patterns of stock returns and the suggestion day-of-the-week return patterns are not robust over time. Therefore, familiarity with market microstructure issues is just as important as the statistical techniques utilized.

High and equitable quality of care are core goals of the English National Health Service. Policy makers have experimented with various ways to improve quality, including use of financial incentives. The effects of these incentives on health outcomes and the distribution of care are not known. The aim of this study was to examine variations in hospital quality and outcomes at patient level under a financial incentive scheme in England. In October 2008 a financial incentive scheme under which quality of care was measured by process measures was introduced for 24 hospital Trusts in the North West of England. The process measures of care from this Advancing Quality initiative were linked at spell level to health outcomes and administrative hospital records. The data consisted of 252,284 spells between October 2008 and March 2013.First, I examined whether financially incentivised improvements in quality of care were associated with better patient outcomes. I examined how mortality and readmission were related to process measures using bivariate probit, probit, random effects and fixed effects estimations. I found that several of the incentivised process measures of care are associated with improved patient outcomes. I estimated that Advancing Quality saved 129 lives and avoided 121 readmissions over a four-and-a-half year period. Second I examined whether quality of care from a hospital incentive scheme is distributed equitably at a patient level. Multinomial and sequential logistic regressions were used to show that process measures of care overall were distributed in favour of patients from lower income score areas. Process measures of care delivered during an emergency admission were distributed in favour of patients from higher income score areas but this was driven by patient severity. Process measures based on advice appeared to be driven by capacity to benefit and were distributed in favour of patients from lower income score areas. Process measures of care for elective admissions regarding delivery of drugs were distributed equitably. Third, I examined if the quality of care was lower at the weekend. The in-hospital mortality rate is known to be higher for weekend admissions than for weekday admissions but it is not known whether this was due to lower quality of care. Using logistic regressions, incentivised quality of care was found to be consistent throughout the week. The weekend mortality effect can be explained by patient volume, which suggested that patient case mix may be different between weekdays and weekends. Overall, quality of care under an incentive scheme was found to positively impact on health outcomes, be distributed equitably, and be the same at weekends as weekdays. Further research is needed using quality of care indicators from all Trusts in the English National Health Service. Furthermore further research examining how trusts exclude patients from financial incentive schemes is also needed.

京都大学 / 0048 / 新制・課程博士 / 博士(社会健康医学) / 甲第22381号 / 社医博第103号 / 新制||社||医11(附属図書館) / 京都大学大学院医学研究科社会健康医学系専攻 / (主査)教授 中山 健夫, 教授 小池 薫, 教授 福原 俊一 / 学位規則第4条第1項該当 / Doctor of Public Health / Kyoto University / DFAM

Acute Upper Gastrointestinal Bleeding (AUGIB) accounts for 7000 deaths in the UK annually and is the single leading indication for transfusion of blood components. A large UK audit in 2007 reported high case fatality and rates of further bleeding. Since many deaths are determined by pre-existing co-morbidity, strategies to improve outcome should be targeted at preventable deaths and therefore focus upon improved control of haemorrhage and prevention of further bleeding, which are investigated in this thesis. Data for the analyses presented originate from the UK national audit of AUGIB, a laboratory study and a cross sectional survey. Five broad themes were investigated including service provision and timing of endoscopy, the use of transcatheter arterial embolisation (TAE) or surgery for refractory bleeding, the impact of coagulopathy on outcome, management of acute variceal haemorrhage (AVH) and haemostatic derangements after AVH, and the use of red blood cells (RBCs). Although there was no evidence of a “weekend effect” for mortality, earlier endoscopy (<12 hours) was associated with improved control of haemorrhage in higher risk patients compared to later endoscopy (>24 hours). TAE was an effective and safe modality for refractory bleeding, but the high post-surgical mortality (29%) raises questions about the appropriateness of case selection for surgery. Coagulopathy after non-variceal haemorrhage was associated with a 5-fold increase in risk-adjusted mortality. Further bleeding after AVH was strikingly high (26%) with notable deficiencies in the use of vasopressors, antibiotics and endotherapy. Global assessments of coagulation demonstrated that thrombin generation after AVH was normal, but clot strength was poor with excessive fibrinolysis. Platelets, fibrinogen and antifibrinolytics improved haemostasis ex vivo but coagulation factor transfusion had no effect. RBC transfusion practice is variable. This work on AUGIB provides new data highlighting areas of sub-optimal care, and informs both current practice and research questions for new interventional trials.

Ground-level ozone (O3) is a familiar pollutant because it is associated with summer haze and smog alerts. The 2000-2008 weekday-weekend variations of ozone concentration were examined in relation to the Toronto weather conditions. The goal of this work is twofold: (1) To determine whether extreme ozone events were associated with specific weather conditions, (2) To determine whether the weekday-weekend effect of extreme ozone events could be detectable during the nine-year study period. The results show that in the study period, there were totally 313 days having extreme ground-level ozone events with ozone concentration ≥ 80 ppb, which is the current Ontario Ambient Air Quality Criterion for ozone concentration, in the four selected Toronto sites. Additionally, the weather condition mainly associated with these 313 days was the Dry Tropical one. This study also shows the phenomenon of the weekday-weekend effect of extreme ozone events in the past nine years in Toronto.

Ground-level ozone (O3) is a familiar pollutant because it is associated with summer haze and smog alerts. The 2000-2008 weekday-weekend variations of ozone concentration were examined in relation to the Toronto weather conditions. The goal of this work is twofold: (1) To determine whether extreme ozone events were associated with specific weather conditions, (2) To determine whether the weekday-weekend effect of extreme ozone events could be detectable during the nine-year study period. The results show that in the study period, there were totally 313 days having extreme ground-level ozone events with ozone concentration ≥ 80 ppb, which is the current Ontario Ambient Air Quality Criterion for ozone concentration, in the four selected Toronto sites. Additionally, the weather condition mainly associated with these 313 days was the Dry Tropical one. This study also shows the phenomenon of the weekday-weekend effect of extreme ozone events in the past nine years in Toronto.

京都大学 / 0048 / 新制・課程博士 / 博士(社会健康医学) / 甲第20288号 / 社医博第77号 / 社新制||医||9(附属図書館) / 京都大学大学院医学研究科社会健康医学系専攻 / (主査)教授 川上 浩司, 教授 一山 智, 教授 伊達 洋至 / 学位規則第4条第1項該当 / Doctor of Public Health / Kyoto University / DGAM

Yes / Routine administrative data have been used to show that patients admitted to hospitals over the weekend appear to have a higher mortality compared to weekday admissions. Such data do not take the severity of sickness of a patient on admission into account. Our aim was to incorporate a standardized vital signs physiological-based measure of sickness known as the National Early Warning Score to investigate if weekend admissions are: sicker as measured by their index National Early Warning Score; have an increased mortality; and experience longer delays in the recording of their index National Early Warning Score. Methods: We extracted details of all adult emergency medical admissions during 2014 from hospital databases and linked these with electronic National Early Warning Score data in four acute hospitals. We analysed 47,117 emergency admissions after excluding 1657 records, where National Early Warning Score was missing or the first (index) National Early Warning Score was recorded outside ±24 h of the admission time. Results: Emergency medical admissions at the weekend had higher index National Early Warning Score (weekend: 2.53 vs. weekday: 2.30, p

O ozônio é um poluente secundário formado pela presença de poluentes atmosféricos primários e secundários formados a partir de uma sequência de reações entre o dióxido de nitrogênio e de compostos orgânicos voláteis (COV). No grupo de compostos orgânicos voláteis estão os aldeídos e os BTEX. Os COVS são emitidos, no Rio de Janeiro, principalmente por veículos automotores. O presente estudo realizou então coletas de aldeídos e BTEX no período de 2013. Além disso, com dados de 2012 e 2013 de poluentes de uma rede automática de monitoramento analisou o possível efeito fim de semana existente na região. O efeito fim de semana é caracterizado por altas concentrações de ozônio no final de semana mesmo com a redução da frota das emissões de NOx e COVs neste período. / Ozone is a secondary pollutant formed in the presence of primary and other secondary pollutants in a sequence of reactions between nitrogen dioxide and volatile organic compounds (VOC). In the chemical group of volatile organic compounds are included aldehydes and BTEX. VOC are emitted in the city of Rio de Janeiro primarily by automobile vehicles. This study performed sampling of aldehydes and BTEX in the period of the year of 2013. Besides, using data imported of an automatic pollutant monitoring net of the years of 2012 and 2013, this study analyzed the possible weekend effect in this region. The weekend effect is characterized by high concentrations of ozone in the weekends, even with the reduction of the traffic, and the consequent reduction of the emissions of NOx and VOC in this period.

O ozônio é um poluente secundário formado pela presença de poluentes atmosféricos primários e secundários formados a partir de uma sequência de reações entre o dióxido de nitrogênio e de compostos orgânicos voláteis (COV). No grupo de compostos orgânicos voláteis estão os aldeídos e os BTEX. Os COVS são emitidos, no Rio de Janeiro, principalmente por veículos automotores. O presente estudo realizou então coletas de aldeídos e BTEX no período de 2013. Além disso, com dados de 2012 e 2013 de poluentes de uma rede automática de monitoramento analisou o possível efeito fim de semana existente na região. O efeito fim de semana é caracterizado por altas concentrações de ozônio no final de semana mesmo com a redução da frota das emissões de NOx e COVs neste período. / Ozone is a secondary pollutant formed in the presence of primary and other secondary pollutants in a sequence of reactions between nitrogen dioxide and volatile organic compounds (VOC). In the chemical group of volatile organic compounds are included aldehydes and BTEX. VOC are emitted in the city of Rio de Janeiro primarily by automobile vehicles. This study performed sampling of aldehydes and BTEX in the period of the year of 2013. Besides, using data imported of an automatic pollutant monitoring net of the years of 2012 and 2013, this study analyzed the possible weekend effect in this region. The weekend effect is characterized by high concentrations of ozone in the weekends, even with the reduction of the traffic, and the consequent reduction of the emissions of NOx and VOC in this period.