Generalized Sums over Histories for Quantum Gravity II. Simplicial Conifolds

This paper examines the issues involved with concretely implementing a sum over conifolds in the formulation of Euclidean sums over histories for gravity. The first step in precisely formulating any sum over topological spaces is that one must have an algorithmically implementable method of generating a list of all spaces in the set to be summed over. This requirement causes well known problems in the formulation of sums over manifolds in four or more dimensions; there is no algorithmic method of determining whether or not a topological space is an n-manifold in five or more dimensions and the issue of whether or not such an algorithm exists is open in four. However, as this paper shows, conifolds are algorithmically decidable in four dimensions. Thus the set of 4-conifolds provides a starting point for a concrete implementation of Euclidean sums over histories in four dimensions. Explicit algorithms for summing over various sets of 4-conifolds are presented in the context of Regge calculus. Postscript figures available via anonymous ftp at black-hole.physics.ubc.ca (137.82.43.40) in file gen2.ps.Comment: 82pp., plain TeX, To appear in Nucl. Phys. B,FF-92-

ASoP (v1.0): a set of methods for analyzing scales of precipitation in general circulation models

General circulation models (GCMs) have been criticized for their failure to represent the observed scales of precipitation, particularly in the tropics where simulated daily rainfall is too light, too frequent, and too persistent. Previous assessments have focused on temporally or spatially averaged precipitation, such as daily means or regional averages. These evaluations offer little actionable information for model developers, because the interactions between the resolved dynamics and parameterized physics that produce precipitation occur at the native gridscale and timestep. We introduce a set of diagnostics (ASoP1) to compare the spatial and temporal scales of precipitation across GCMs and observations, which can be applied to data ranging from the gridscale and timestep to regional and sub-monthly averages. ASoP1 measures the spectrum of precipitation intensity, temporal variability as a function of intensity, and spatial and temporal coherence. When applied to timestep, gridscale tropical precipitation from ten GCMs, the diagnostics reveal that far from the "dreary" persistent light rainfall implied by daily mean data, most models produce a broad range of timestep intensities that span 1-100 mm/day. Models show widely varying spatial and temporal scales of timestep precipitation. Several GCMs show concerning quasi-random behavior that may influence alter the spectrum of atmospheric waves. Averaging precipitation to a common spatial (~600 km) or temporal (3-hr) resolution substantially reduces variability among models, demonstrating that averaging hides a wealth of information about intrinsic model behavior. When compared against satellite-derived analyses at these scales, all models produce features that are too large and too persistent

Connecting spatial and temporal scales of tropical precipitation in observations and the MetUM-GA6

This study analyses tropical rainfall variability, on a range of temporal and spatial scales, in a set of parallel Met Office Unified Model (MetUM) simulations at a range of horizontal resolutions, compared with two satellite-derived rainfall datasets. We focus on the shorter scales i.e. from the native grid and time-step of the model through sub-daily to seasonal, since previous studies have paid relatively little attention to sub-daily rainfall variability and how this feeds through to longer scales. We find that the behaviour of the deep convection parametrization in this model on the native grid and time-step is largely independent of the grid-box size and time-step length over which it operates. There is also little difference in the rainfall variability on larger/longer spatial/temporal scales. Tropical convection in the model on the native grid/time-step is spatially and temporally intermittent, producing very large rainfall amounts interspersed with grid-boxes/time-steps of little or no rain. In contrast, switching off the deep convection parametrization, albeit at an unrealistic resolution for resolving tropical convection, results in very persistent (for limited periods), but very sporadic, rainfall. In both cases, spatial and temporal averaging smoothes out this intermittency. On the ~100 km scale, for oceanic regions, the spectra of 3-hourly and daily mean rainfall in the configurations with parametrized convection agree fairly well with those from satellite-derived rainfall estimates, while at ~10 day timescales the averages are overestimated, indicating a lack of intra-seasonal variability. Over tropical land the results are more varied, but the model often underestimates the daily mean rainfall (partly as a result of a poor diurnal cycle) but still lacks variability on intra-seasonal timescales. Ultimately, such work will shed light on how uncertainties in modelling the small/short scale processes relate to uncertainty in climate change projections of rainfall distribution and variability, with a view to reducing such uncertainty through improved modelling of the small/short scale processes

Antihypertensive Drug Class and Adherence: An Electronic Monitoring Study

Background: Medication adherence is essential to optimizing blood pressure (BP) control. Prior research has demonstrated differences in pharmacy refill patterns according to antihypertensive drug class. No prior study has assessed the association between drug class and day-to-day adherence. Methods: Between 2011 and 2014, we enrolled a convenience sample of 149 patients with persistently uncontrolled hypertension from two inner-city clinics and concurrently measured adherence of up to four antihypertensive medications using electronic pillboxes during the interval between two primary care visits. The main outcome was mean percent of days adherent to each drug. Mixed effects regression analyses were used to assess the association between drug class and adherence adjusting for age, gender, race, ethnicity, education, health insurance, coronary artery disease, heart failure, chronic kidney disease, diabetes, number of medications, days monitored, and dosing frequency. Results: The mean age was 64 years; 72% women, 75% Hispanic, 88% prescribed ≥1 BP medication. In unadjusted analyses, adherence was lower for beta-blockers (70.9%) compared to angiotensin receptor blocking agents (75.0%, P = 0.11), diuretics (75.9%, P < 0.001), calcium channel blockers (77.6%, P < 0.001) and angiotensin-converting enzyme inhibitors (78.0%, P < 0.0001). In the adjusted analysis, only dosing frequency (P = 0.0001) but not drug class (P = 0.71) was associated with medication adherence. Conclusions: Antihypertensive drug class was not associated with electronically measured adherence after accounting for dosing frequency amongst patients with uncontrolled hypertension. Low adherence to beta-blockers may have been due to the common practice of prescribing multiple daily dosing. Providers may consider using once daily formulations to optimize adherence and should assess adherence among all treated patients with uncontrolled hypertension. Key words: blood pressure drug class hypertension medication adherence

Elucidating the Association Between Depressive Symptoms, Coronary Heart Disease, and Stroke in Black and White Adults: The REasons for Geographic And Racial Differences in Stroke (REGARDS) Study

Background Depression is a relapsing and remitting disease. Prior studies on the association between depressive symptoms and incident cardiovascular disease (CVD) have been limited by single measurements, and few if any have examined both incident coronary heart disease and stroke in a large biracial national cohort. We aimed to assess whether time‐dependent depressive symptoms conferred increased risk of incident CVD. Methods and Results Between 2003 to 2007, 22 666 black and white participants (aged ≥45 years) without baseline CVD in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study were recruited. Cox proportional hazards regression analyses assessed the association between up to 3 measurements of elevated depressive symptoms (4‐item Center for Epidemiologic Studies Depression Scale score ≥4) and incident coronary heart disease, stroke, and CVD death adjusting for age, sex, region, income, health insurance, education, blood pressure, cholesterol, medication, obesity, diabetes mellitus, kidney disease, C‐reactive protein, corrected QT interval, atrial fibrillation, left ventricular hypertrophy, smoking, alcohol, physical inactivity, medication adherence, and antidepressant use. The participants’ average age was 63.4 years, 58.8% were female, and 41.7% black. Time‐varying depressive symptoms were significantly associated with CVD death (adjusted hazard ratio 1.30, 95% CI 1.04–1.63), with a trend toward significance for fatal and nonfatal stroke (adjusted hazard ratio 1.26, 95% CI 0.99–1.60) but not fatal and nonfatal coronary heart disease (adjusted hazard ratio 1.11, 95% CI 0.89–1.38). Race did not moderate the association between depressive symptoms and CVD. Conclusions Proximal depressive symptoms were associated with incident fatal and nonfatal stroke and CVD death even after controlling for multiple explanatory factors, further supporting the urgent need for timely management of depressive symptoms

Undergraduate public relations education in the United Kingdom: Quo Vadis?

In the current context of the undergraduate PR academic education in the United Kingdom degrees being shut down or merged with other communication disciplines, the present essay represents a timely reflection on the results and internal incoherence of PR education provision in the United Kingdom. Starting from the key idea that public relations is a mature occupation and academic social discipline, we developed a thorough analysis of PR fields, where we analysed the intra- and inter-dynamics between these various types of fields, aiming at identifying the main issues that impact the teaching of PR and its academic expressions. Drawn from the field analysis, we then focused on two key trends which currently shape the undergraduate PR education in the UK to recommend changes to the process of curriculum development that reconstructs the social value of Public Relations

Objectively Measured Adherence to Physical Activity Guidelines After Acute Coronary Syndrome

Physical activity is a cornerstone of secondary prevention after acute coronary syndromes (ACS). Guidelines strongly recommend that post-ACS patients achieve ≥30 min of moderate aerobic activity such as brisk walking on at least 5 days per week within 2 weeks of discharge (1). Yet, little is known about the extent to which post-ACS patients are meeting physical activity guidelines. Prior studies assessing physical activity after ACS were limited by reliance on self-reports (2). The purpose of this study was to use an objective measure of physical activity to describe the proportion of ACS patients following physical activity recommendations in the high-risk post-discharge period. Between 2009 and 2012, we enrolled patients hospitalized for myocardial infarction (MI) or unstable angina into the PULSE (Prescription Use, Lifestyle, and Stress Evaluation) study. Some patients participated in an ancillary study in which they were provided with an Actical accelerometer (Philips Respironics, Bend, Oregon) at or soon after discharge (3). Patients were asked to continuously wear the device on their nondominant wrist and to return the device 1 month later. All patients provided informed consent. The institutional review board of Columbia University Medical Center approved the study