University of Alberta

About: University of Alberta is a education organization based out in Edmonton, Alberta, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 65403 authors who have published 154847 publications receiving 5358338 citations. The organization is also known as: Ualberta & UAlberta.

Refinements in electroweak contributions to the muon anomalous magnetic moment

Abstract: Effects of strong interactions on the two loop electroweak radiative corrections to the muon anomalous magnetic moment, $a_\mu=(g_\mu-2)/2$, are examined. Short-distance logs are shown to be unaffected. Computation of long-distance contributions is improved by use of an effective field theory approach that preserves the chiral properties of QCD and accounts for constraints from the operator product expansion. Small, previously neglected, two loop contributions, suppressed by a $1-4\sin^2\theta_W$ factor, are computed and the complete three loop leading short-distance logs are reevaluated. These refinements lead to a reduction in uncertainties and a slight shift in the total electroweak contribution to $a_\mu^{\rm EW} = 154(1)(2)\times 10^{-11}$ where the first error corresponds to hadronic uncertainties and the second is primarily due to the allowed Higgs mass range.

Acute kidney injury—epidemiology, outcomes and economics

Abstract: Acute kidney injury (AKI) is a widespread problem of epidemic status. Compelling evidence indicates that the incidence of AKI is rapidly increasing, particularly among hospitalized patients with acute illness and those undergoing major surgery. This increase might be partially attributable to greater recognition of AKI, improved ascertainment in administrative data and greater sensitivity of consensus diagnostic and classification schemes. Other causes could be an ageing population, increasing incidences of cardiovascular disease, diabetes mellitus and chronic kidney disease (CKD), and an expanding characterization of modifiable risk factors, such as sepsis, administration of contrast media and exposure to nephrotoxins. The sequelae of AKI are severe and characterized by increased risk of short-term and long-term mortality, incident CKD and accelerated progression to end-stage renal disease. AKI-associated mortality is decreasing, but remains unacceptably high. Moreover, the absolute number of patients dying as a result of AKI is increasing as the incidence of the disorder increases, and few proven effective preventative or therapeutic interventions exist. Survivors of AKI, particularly those who remain on renal replacement therapy, often have reduced quality of life and consume substantially greater health-care resources than the general population as a result of longer hospitalizations, unplanned intensive care unit admissions and rehospitalizations.

The dilemma of controlling cultural eutrophication of lakes.

Abstract: The management of eutrophication has been impeded by reliance on short-term experimental additions of nutrients to bottles and mesocosms. These measures of proximate nutrient limitation fail to account for the gradual changes in biogeochemical nutrient cycles and nutrient fluxes from sediments, and succession of communities that are important components of whole-ecosystem responses. Erroneous assumptions about ecosystem processes and lack of accounting for hysteresis during lake recovery have further confused management of eutrophication. I conclude that long-term, whole-ecosystem experiments and case histories of lake recovery provide the only reliable evidence for policies to reduce eutrophication. The only method that has had proven success in reducing the eutrophication of lakes is reducing input of phosphorus. There are no case histories or long-term ecosystem-scale experiments to support recent claims that to reduce eutrophication of lakes, nitrogen must be controlled instead of or in addition to phosphorus. Before expensive policies to reduce nitrogen input are implemented, they require ecosystem-scale verification. The recent claim that the ‘phosphorus paradigm’ for recovering lakes from eutrophication has been ‘eroded’ has no basis. Instead, the case for phosphorus control has been strengthened by numerous case histories and large-scale experiments spanning several decades.

NMR Spectroscopy for Metabolomics Research.

Abstract: Over the past two decades, nuclear magnetic resonance (NMR) has emerged as one of the three principal analytical techniques used in metabolomics (the other two being gas chromatography coupled to mass spectrometry (GC-MS) and liquid chromatography coupled with single-stage mass spectrometry (LC-MS)). The relative ease of sample preparation, the ability to quantify metabolite levels, the high level of experimental reproducibility, and the inherently nondestructive nature of NMR spectroscopy have made it the preferred platform for long-term or large-scale clinical metabolomic studies. These advantages, however, are often outweighed by the fact that most other analytical techniques, including both LC-MS and GC-MS, are inherently more sensitive than NMR, with lower limits of detection typically being 10 to 100 times better. This review is intended to introduce readers to the field of NMR-based metabolomics and to highlight both the advantages and disadvantages of NMR spectroscopy for metabolomic studies. It will also explore some of the unique strengths of NMR-based metabolomics, particularly with regard to isotope selection/detection, mixture deconvolution via 2D spectroscopy, automation, and the ability to noninvasively analyze native tissue specimens. Finally, this review will highlight a number of emerging NMR techniques and technologies that are being used to strengthen its utility and overcome its inherent limitations in metabolomic applications.

A meta-analysis of neuropsychological change to clozapine, olanzapine, quetiapine, and risperidone in schizophrenia

Abstract: Cognitive impairment is a core feature of schizophrenia and a major impediment to social and vocational rehabilitation. A number of studies have claimed cognitive benefits from treatment with various atypical antipsychotic drugs (APDs). The currently available evidence supporting cognitive improvement with atypical APDs was evaluated in two meta-analyses. Studies that (1) prospectively examined cognitive change to the atypical APDs clozapine, olanzapine, quetiapine, and risperidone, (2) included a commonly used neuropsychological test, and (3) provided data from which relevant effect sizes could be calculated, were included. Forty-one studies met these criteria. Neuropsychological test data from each study were combined into a Global Cognitive Index and nine cognitive domain scores. Two meta-analyses were carried out. The first included 14 controlled, random assignment trials that assigned subjects to an atypical APD and a typical APD control arm. The second analysis included all prospective investigations of atypical treatment and the within-group change score divided by its standard deviation served as an estimate of effect size (ES). The first analysis revealed that atypicals are superior to typicals at improving overall cognitive function (ES=0.24). Specific improvements were observed in the learning and processing speed domains. The second analysis extended the improvements to a broader range of cognitive domains (ES range=0.17-0.46) and identified significant differences between treatments in attention and verbal fluency. Moderator variables such as study blind and random assignment influence results of cognitive change to atypical APDs. Atypical antipsychotics produce a mild remediation of cognitive deficits in schizophrenia, and specific atypicals have differential effects within certain cognitive domains.