University of Victoria

About: University of Victoria is a education organization based out in Victoria, British Columbia, Canada. It is known for research contribution in the topics: Population & Galaxy. The organization has 14994 authors who have published 41051 publications receiving 1447972 citations. The organization is also known as: Victoria College.

Changes in soil organic carbon storage predicted by Earth system models during the 21st century

Abstract: . Soil is currently thought to be a sink for carbon; however, the response of this sink to increasing levels of atmospheric carbon dioxide and climate change is uncertain. In this study, we analyzed soil organic carbon (SOC) changes from 11 Earth system models (ESMs) contributing simulations to the Coupled Model Intercomparison Project Phase 5 (CMIP5). We used a reduced complexity model based on temperature and moisture sensitivities to analyze the drivers of SOC change for the historical and high radiative forcing (RCP 8.5) scenarios between 1850 and 2100. ESM estimates of SOC changed over the 21st century (2090–2099 minus 1997–2006) ranging from a loss of 72 Pg C to a gain of 253 Pg C with a multi-model mean gain of 65 Pg C. Many ESMs simulated large changes in high-latitude SOC that ranged from losses of 37 Pg C to gains of 146 Pg C with a multi-model mean gain of 39 Pg C across tundra and boreal biomes. All ESMs showed cumulative increases in global NPP (11 to 59%) and decreases in SOC turnover times (15 to 28%) over the 21st century. Most of the model-to-model variation in SOC change was explained by initial SOC stocks combined with the relative changes in soil inputs and decomposition rates (R2 = 0.89, p

Phase-space structure in the local dark matter distribution and its signature in direct detection experiments

Abstract: We study predictions for dark matter phase-space structure near the Sun based on highresolution simulations of six galaxy halos taken from the Aquarius Project. The local DM density distribution is predicted to be remarkably smooth; the density at the Sun differs from the mean over a best-fit ellipsoidal equidensity contour by less than 15% at the 99.9% confidence level. The local velocity distribution is also very smooth, but it differs systematically from a (multivariate) Gaussian distribution. This is not due to th e presence of individual clumps or streams, but to broad features in the velocity modulus and energy distributions that are stable both in space and time and reflect the detailed assembly histo ry of each halo. These features have a significant impact on the signals predicted for WIMP an d axion searches. For example, WIMP recoil rates can deviate by � 10% from those expected from the best-fit multivariate Gaussian models. The axion spectra in our simulations typically peak at lower frequencies than in the case of multivariate Gaussian velocity distribu tions. Also in this case, the spectra show significant imprints of the formation of the halo. Th is implies that once direct DM detection has become routine, features in the detector sign al will allow us to study the dark matter assembly history of the Milky Way. A new field, “dark ma tter astronomy”, will then emerge.

Alcohol Volume, Drinking Pattern, and Cardiovascular Disease Morbidity and Mortality: Is There a U-shaped Function?

Abstract: The health effects of a binge pattern of alcohol consumption have not been widely investigated. The objective of this study was to evaluate the cardiovascular consequences of binge drinking (consumption of eight or more drinks at one sitting) and usual (nonbinge) drinking in a longitudinal, population-based study. Data obtained from 1,154 men and women aged 18-64 years interviewed in Winnipeg, Manitoba, Canada, in 1990 and 1991 were linked to health care utilization and mortality records. Using an 8-year follow-up period, the authors performed separate Cox proportional hazards regression analyses for men and women on time to first event for physician visits, hospitalizations, and deaths due to coronary heart disease, hypertension, and other cardiovascular disease. Binge drinking increased the risk of coronary heart disease in both men (hazard ratio (HR) = 2.26, 95% confidence interval (CI): 1.22, 4.20) and women (HR = 1.10, 95% CI: 1.02, 1.18). It increased the risk of hypertension in men (HR = 1.57, 95% CI: 1.04, 2.35) but not in women. Binge drinking had no effect on the risk of other cardiovascular disease. In contrast, usual drinking had significant cardioprotective effects in both men and women. Thus, the harmful effects of binge drinking on cardiovascular disease morbidity and mortality can be disaggregated from the protective effects of usual drinking at various levels of consumption.

The unity and diversity of executive functions: A systematic review and re-analysis of latent variable studies.

Abstract: Confirmatory factor analysis (CFA) has been frequently applied to executive function measurement since first used to identify a three-factor model of inhibition, updating, and shifting; however, subsequent CFAs have supported inconsistent models across the life span, ranging from unidimensional to nested-factor models (i.e., bifactor without inhibition). This systematic review summarized CFAs on performance-based tests of executive functions and reanalyzed summary data to identify best-fitting models. Eligible CFAs involved 46 samples (N = 9,756). The most frequently accepted models varied by age (i.e., preschool = one/two-factor; school-age = three-factor; adolescent/adult = three/nested-factor; older adult = two/three-factor), and most often included updating/working memory, inhibition, and shifting factors. A bootstrap reanalysis simulated 5,000 samples from 21 correlation matrices (11 child/adolescent; 10 adult) from studies including the three most common factors, fitting seven competing models. Model results were summarized as the mean percent accepted (i.e., average rate at which models converged and met fit thresholds: CFI ≥ .90/RMSEA ≤ .08) and mean percent selected (i.e., average rate at which a model showed superior fit to other models: ΔCFI ≥ .005/.010/ΔRMSEA ≤ -.010/-.015). No model consistently converged and met fit criteria in all samples. Among adult samples, the nested-factor was accepted (41-42%) and selected (8-30%) most often. Among child/adolescent samples, the unidimensional model was accepted (32-36%) and selected (21-53%) most often, with some support for two-factor models without a differentiated shifting factor. Results show some evidence for greater unidimensionality of executive function among child/adolescent samples and both unity and diversity among adult samples. However, low rates of model acceptance/selection suggest possible bias toward the publication of well-fitting but potentially nonreplicable models with underpowered samples. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Mediators of physical activity behaviour change among adult non-clinical populations: a review update.

Abstract: Background An understanding of the determinants of physical activity through mediators of behaviour change is important in order to evaluate the efficacy of interventions. Prior reviews on this topic noted that few studies employed mediator analyses in experimental physical activity trials; the purpose of this review is to update these prior reviews in order to evaluate the state of our present understanding of interventions that include proposed mediators of behaviour change.