711 research outputs found
The Effect of Storage on Runoff from a Headwater Subarctic Shield Basin
Canadian Shield runoff production processes have been investigated, but research is needed beyond the hillslope scale to determine the influences on the volume and timing of runoff from headwater basins to higher-order streams. Such research will permit an understanding of the magnitude of climate change impacts at the watershed scale, where changes in the hydrologic regime are felt most by water resource users. To this end, water budget terms were measured over different portions of a headwater lake basin north of Yellowknife, Northwest Territories, during the spring snowmelt of 1998 to determine the relative importance of each component as water moved through the basin. Evaporation made up 16% and runoff 70% of the snowmelt from upland areas. Upland ponding of water during the melt increased the evaporative loss. Headwater lake storage deficits are very important in the timing and volume of runoff that is transmitted downstream: 53% of basin meltwater went to meeting the storage deficit in the lake so that only 7% of the meltwater was routed out of the basin. These results imply that topology of shield headwater basins, notably the location of lakes and antecedent water levels in lakes, are important in determining the runoff response. As storage deficits in surface waters will cause changes over space in runoff response and timing, it may be inappropriate to consider the snowpack or rainfall volume in isolation when forecasting runoff volume. These results are important for water management and hydrological modeling applications of northern shield basins.On a Ă©tudiĂ© les processus qui entraĂźnent la production de ruissellement sur le Bouclier canadien, mais il faut envisager la recherche d'un point de vue plus global que l'Ă©chelle des versants, afin de dĂ©terminer les facteurs qui influencent le volume et la pĂ©riodicitĂ© du ruissellement provenant des bassins d'amont vers des cours d'eau d'ordre plus Ă©levĂ©. Une telle recherche permettra de mieux saisir l'importance des retombĂ©es du changement climatique Ă l'Ă©chelle du bassin hydrographique, oĂč les changements dans le rĂ©gime hydrologique sont le plus ressentis par les usagers des ressources en eau. Ă cette fin, on a mesurĂ© le bilan hydrique sur plusieurs sections d'un bassin lacustre d'amont au nord de Yellowknife, dans les Territoires du Nord-Ouest, durant la fonte des neiges au printemps de 1998, pour dĂ©terminer l'importance relative de chaque Ă©lĂ©ment, Ă mesure que l'eau traversait le bassin. L'Ă©vaporation reprĂ©sentait jusqu'Ă 16 p. cent et le ruissellement 70 p. cent de la fusion nivale venant des hautes terres. Ă ces endroits, l'accumulation d'eau dans des dĂ©pressions durant la fonte augmentait la perte due Ă l'Ă©vaporation. Les dĂ©ficits dans les rĂ©serves lacustres d'amont ont une influence majeure sur le rythme et le volume du ruissellement qui passe en aval: 53 p. cent de l'eau de fonte du bassin allait compenser le dĂ©ficit des rĂ©serves du lac, de sorte que seulement 7 p. cent de l'eau de fonte se dirigeait hors du bassin. Ces rĂ©sultats laissent entendre que la topologie des bassins d'amont du Bouclier, en particulier l'emplacement des lacs et leurs niveaux d'eau antĂ©rieurs, est importante pour dĂ©terminer la rĂ©ponse du ruissellement. Vu que les dĂ©ficits des rĂ©serves d'eau de surface amĂšneront des changements spatiaux dans la rĂ©ponse et le rythme du ruissellement, il ne convient sans doute pas de considĂ©rer simplement le volume du manteau nival ou des prĂ©cipitations quand on veut prĂ©voir le volume de ruissellement. Ces rĂ©sultats sont importants pour la gestion de l'eau et les applications de modĂ©lisation hydrologique des bassins du Bouclier septentrional
Small Business and Social Irresponsibility in Developing Countries:Working Conditions and âEvasionâ Institutional Work
Small businesses in developing countries, as part of global supply chains, are sometimes assumed to respond in a straightforward manner to institutional demands for improved working conditions. This article problematizes this perspective. Drawing upon extensive qualitative data from Tirupurâs knitwear export industry in India, we highlight owner-managersâ agency in avoiding or circumventing these demands. The small businesses here actively engage in irresponsible business practices and âevasionâ institutional work to disrupt institutional demands in three ways: undermining assumptions and values, dissociating consequences, and accumulating autonomy and political strength. This âevasionâ work is supported by three conditions: void (in labor welfare mechanisms), distance (from institutional monitors), and contradictions (between value systems). Through detailed empirical findings, the article contributes to research on both small business social responsibility and institutional work. </jats:p
The impact of brain iron accumulation on cognition : A systematic review
Funding: Principal Grant Holder: GW Funder: The Roland Sutton Academic Trust https://www.abdn.ac.uk/ims/research/abic/roland-sutton-academic-trust-1427.php Sponsers only provided financial support.Peer reviewedPublisher PD
The Magnificent Seven : understanding builds better bridges (and culverts)
Global Water Futures
Canada Research Excellence FundNon-Peer ReviewedPersonal account of how a Global Water Futures project team worked with land users to inform the contentious issue of prairie wetland drainage
The Likely Impact of Mandated Paid Sick and Family-Care Leave on the Economy and Economic Development Prospects of the State of Ohio
This report analyzes the potential impact of a proposed paid sick and family care leave legislation on the economy of the state of Ohio, the economic development prospects of the state and on the management of production processes that depend on highly integrate teams. The report also reviews the literature on the effect of mandated paid sick and family care leave on the industrial relations systemâworkplace performance and worker retention. Our analysis concludes that there would have been a net cost associated with the paid sick leave and family-care initiative proposed in Ohio with a lower bound estimate of 260.48 annual net cost per newly covered worker. We estimate that 1.6 million workers would have gained paid sick and family care leave if the proposed initiative were enacted in Ohio; therefore, our lower bound estimate is that the total net cost in Ohio would be 420.0 million dollars per year. This estimated range is the minimum impact on the state. It does not include the dynamic, economic development impacts. Our cost benefit analysis looks at the short run impacts and does not include longer term negative effects that result from Ohio losing investment to border states as companies seek to avoid the mandates
Supramolecular Chemistry: A Capstone Course
A fourth-year capstone course offers students an opportunity to integrate topics covered in the core disciplinary courses, to learn an advanced interdisciplinary topic, and to approach unfamiliar problems and literature. This article describes a fourth-year capstone course designed to incorporate components of faculty lectures, student seminars, and original, hands-on research projects in order to cover the topic of supramolecular chemistry in one semester with unusual depth. This approach should be applicable to other advanced topics in chemistry
Conformal topological Yang-Mills theory and de Sitter holography
A new topological conformal field theory in four Euclidean dimensions is
constructed from N=4 super Yang-Mills theory by twisting the whole of the
conformal group with the whole of the R-symmetry group, resulting in a theory
that is conformally invariant and has two conformally invariant BRST operators.
A curved space generalisation is found on any Riemannian 4-fold. This
formulation has local Weyl invariance and two Weyl-invariant BRST symmetries,
with an action and energy-momentum tensor that are BRST-exact. This theory is
expected to have a holographic dual in 5-dimensional de Sitter space.Comment: 34 pages, AMSTex, Reference adde
Pragmatic engagement in a low trust supply chain: Beef farmersâ perceptions of power, trust and agency
The academic discussion of power in supply chains has changed from a discussion of the use of coercive power to one which emphasizes the role of trust in embedding co-operation and disincentivizing opportunism. Whilst a number of empirical studies have suggested the former is alive and well, this paper argues that power relations may also be constituted by the self-perceptions of weaker actors as much as by the explicit actions of more powerful ones. This study explores the role of power through the perceptions of subjugated actors, which set the ârules of the gameâ. Our case centres on perceptions of Northern Irish beef farmers and their reflections on their âpowerlessnessâ in relation to the larger, more consolidated processors that they sell to. We find that the way farmers make sense of the power relations they encounter is influenced by the individuating character of the power relations exercised by the processors, which debilitates their ability to collaborate and resist collectively. What emerges is a story about the process of accommodation whereby farmers pragmatically resign themselves to play by âthe rules of the gameâ to remain âpart of the gameâ
3D ultrasound measurement of change in carotid plaque volume: A tool for rapid evaluation of new therapies
Background and Purpose - New therapies are being developed that are antiatherosclerotic but that lack intermediate end points, such as changes in plasma lipids, which can be measured to test efficacy. To study such treatments, it will be necessary to directly measure changes in atherosclerosis. The study was designed to determine sample sizes needed to detect effects of treatment using 3D ultrasound (US) measurement of carotid plaque. Methods - In 38 patients with carotid stenosis \u3e60%, age±SD 69.42±7.87 years, 15 female, randomly assigned in a double-blind fashion to 80 mg atorvastatin daily (n=17) versus placebo (n=21), we measured 3D plaque volume at baseline and after 3 months by disc segmentation of voxels representing carotid artery plaque, after 3D reconstruction of parallel transverse duplex US scans into volumetric 3D data sets. Results - There were no significant differences in baseline risk factors. The rate of progression was 16.81±74.10 mm3 in patients taking placebo versus regression of -90.25±85.12 mm3 in patients taking atorvastatin (P\u3c0.0001). Conclusions - 3D plaque volume measurement can show large effects of therapy on atherosclerosis in 3 months in sample sizes of â20 patients per group. Sample sizes of 22 per group would be sufficient to show an effect size of 25% that of atorvastatin in 6 months. This technology promises to be very useful in evaluation of new therapies. © 2005 American Heart Association, Inc
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