Quantifying the demand-side response capability of industrial plants to participate in power system frequency control schemes

© 2015 IEEE.Efficiency and sustainability considerations have propelled changes in power and process industries. These changes, which include the increased electrification of process industries, are causing concerns about the reliability of future electricity supplies, and therefore motivate the need for a Smart Grid on an industrial scale. This paper presents a method by which process automation engineers can assess the suitability of an oil and gas plant to participate in power system frequency control services. This paper discusses the necessary specifications for an automated system that enables effective variable operation by analysing the safe operating envelope of the plant. To do that, this paper proposes a methodology to characterise the appropriate actuators, variables and limits of set-point change. This methodology is applied to a case study representing an oil processing facility. The resulting analysis indicates demandside response capability that the facility can provide without jeopardising operations on-site

The short-term impact of the alcohol act on alcohol-related deaths and hospital admissions in Scotland: a natural experiment

Background and aim: The introduction of the Alcohol Act in Scotland on 1 October 2011, which included a ban on multi-buy promotions, was likely associated with a fall in off-trade alcohol sales in the year after its implementation. The aim of this study was to test if the same legislation was associated with reduced levels of alcohol-related deaths and hospital admissions in the 3-year period after its introduction. Design: A natural experiment design using time series data to assess the impact of the Alcohol Act legislation in Scotland. Comparisons were made with unexposed populations in the rest of Great Britain. Setting Scotland with comparable data obtained for geographical control groups in other parts of Great Britain. Participants: For alcohol-related deaths, a total of 17,732 in Scotland and 88,001 in England/Wales across 169 four-week periods between January 2001 and December 2013. For alcohol-related hospital admissions, a total of 121,314 in Scotland and 696,892 in England across 182 four-week periods between January 2001 and December 2014. Measurements: Deaths and hospital admissions in Scotland and control groups that were wholly attributable to alcohol for consecutive four-week periods between January 2001 and December 2014. Data were obtained by age, sex and area-based socioeconomic position. Findings: There was no evidence to suggest that the Alcohol Act was associated with changes in the overall rate of alcohol-related deaths [incidence rate ratio (IRR) 0.99, 95% confidence interval (0.91 to 1.07)] or hospital admissions [IRR 0.98 (0.95 to 1.02)] in Scotland. In control group analyses, the pseudo intervention variable was not associated with a change in alcohol-related death rates in England/Wales [IRR 0.99 (0.95 to 1.02)], but was associated with an increase in alcohol-related hospital admission rates in England [IRR 1.05 (1.03 to 1.07)]. In combined models, the interaction analysis did not provide support for a ‘net effect’ of the legislation on alcohol-related deaths in Scotland compared with England/Wales [IRR 0.99 (0.95 to 1.04)], but suggested a net reduction in hospital admissions for Scotland compared with England [IRR 0.93 (0.87 to 0.98)]. Conclusion: The implementation of the Alcohol Act in Scotland has not been associated clearly with a reduction in alcohol-related deaths or hospital admissions in the 3-year period after it was implemented in October 2011

Patterns of antihypertensive prescribing, discontinuation and switching among a Hong Kong Chinese population from over one million prescriptions

Hypertension is an alarming public health problem among Chinese. The present study evaluated the prescribing patterns, discontinuation and switching profiles of antihypertensive agents and their associated factors in one Hong Kong Chinese population. Data were retrieved from computerized records for patients prescribed anti-hypertensive agents in government primary care clinics of Hong Kong from January, 2004 to June, 2007. A total of 1,069,836 antihypertensive drug visits, representing 67,028 patients, were analyzed. The most commonly prescribed drugs were Calcium Channel Blockers (CCBs) (49%), b-Blockers (BBs) (46%) and Angiotensin-Converting Enzyme Inhibitors (ACEIs) (19%). Thiazide diuretic prescribing was low (13%) and on the decline (14% in 2004 to 12% in 2007). Prescribing of ACEIs was rising (16% in 2004 to 23% in 2007). Patients’ age, gender, and socio-economic status were independent predictors of class of anti-hypertensive prescribed but explained less than 3.5% of the variation observed. Drug discontinuation was highest for BBs (21%) and lowest for CCBs (12%). The high rates of discontinuation in BBs remained apparent after controlling for confounding variables. Switching was less common than discontinuation and was most likely with thiazide diuretics. To summarize, prescribing of CCBs and BBs were high and that of thiazide diuretics particularly low in this Chinese population when compared with international trends. CCBs may be a particularly favorable antihypertensive treatment in Chinese, given the high discontinuation rates of BBs and international guidelines advising against the use of BBs as first-line therapy. The low use of thiazide diuretics warrants further clinical and cost effectiveness studies among Chinese

Quasi-experimental study designs series – Paper 10: Synthesizing evidence for effects collected from quasi-experimental studies presents surmountable challenges

Objective: To outline issues of importance to analytic approaches to the synthesis of quasi-experiments (QEs), and to provide a statistical model for use in analysis. Study Design and Setting: We drew on the literatures of statistics, epidemiology, and social-science methodology to outline methods for synthesis of QE studies. The design and conduct of quasi-experiments, effect sizes from QEs, and moderator variables for the analysis of those effect sizes were discussed. Results: Biases, confounding, design complexities and comparisons across designs offer serious challenges to syntheses of QEs. Key components of meta-analyses of QEs were identified, including the aspects of QE study design to be coded and analyzed. Of utmost importance are the design and statistical controls implemented in the QEs. Such controls and any potential sources of bias and confounding must be modeled in analyses, along with aspects of the interventions and populations studied. Because of such controls, effect sizes from QEs are more complex than those from randomized experiments. A statistical meta-regression model that incorporates important features of the QEs under review was presented. Conclusion: Meta-analyses of quasi-experiments provide particular challenges, but thorough coding of intervention characteristics and study methods, along with careful analysis, should allow for sound inferences

The same (as what?)

Aquest article adopta un enfocament radicalment contextualista en relació amb la referència de descripcions definides que contenen l?expressió anglesa the same, tant sense complement com amb complement en forma de nucli nominal i/o de sintagma comparatiu del tipus as X. S?argumenta que les descripcions definides que contenen the same no fan referència a una entitat única, encara que el resultat de la prova de comprensió efectuada sembla donar suport a la idea que aquestes descripcions poden afavorir la interpretació que aquests sintagmes definits es refereixen directament a una entitat específica

Edward Fretheim, Double Bass

Sonata in G minor / Henry Eccles; Chanson Triste / Sergei Koussevitzky; Gavotte / Antonio Lorenziti; Tarantella / Franz Simand

Doing discourse and development

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