1,222 research outputs found

    Product Market Competition and Human Resource Practices: An Analysis of the Retail Food Sector

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    The rise of super-centers and the entry of Wal-Mart into food retailing have dramatically altered the competitive environment in the industry. This paper explores the impact of such changes on the labor market practices of traditional food retailers. We use longitudinal data on workers and firms to construct new measures of compensation and employment, and examine how these measures evolve within and across firms in response to changes in product market structure. An additional feature of the analysis is to combine rich case study knowledge about the retail food industry with the new matched employer-employee data from the Census Bureau.supermarkets, human resource practices, competition, internal labor market, wage growth, Labor and Human Capital, Marketing,

    Ultra high purity, dimensionally stable INVAR 36

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    An INVAR 36 material having long-term dimensional stability is produced by sintering a blend of powders of nickel and iron under pressure in an inert atmosphere to form an alloy containing less than 0.01 parts of carbon and less than 0.1 part aggregate and preferably 0.01 part individually of Mn, Si, P, S and Al impurities. The sintered alloy is heat treated and slowly and uniformly cooled to form a material having a coefficient of thermal expansion of less than 1 ppm/C and a temporal stability of less than 1 ppm/year

    Sediment supply and barrier dynamics as driving mechanisms of Holocene coastal change for the southern North Sea basin

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    The combined effects of climate change and human impact lead to regional and local coastal responses that pose major challenges for the future resilience of coastal landscapes, increasing the vulnerability of communities, infrastructure and nature conservation interests. Using the Suffolk coast, southeast England, as a case study, we investigate the importance of sediment supply and barrier dynamics as driving mechanisms of coastal change throughout the Holocene. Litho-, bio- and chronostratigraphic methods are used to decipher the mechanisms of coastal change from the record preserved within coastal stratigraphy. Results suggest that local coastal configuration and sediment supply were the most influential in determining coastal change during the mid- and late Holocene, against a background control of sea-level rise. The importance of sedimentological and morphological factors in shaping Holocene coastal changes in the southern North Sea basin must therefore be considered when using the database of evidence from this region as an analogue for future change under accelerated sea-level rise

    Endovascular repair of an actively hemorrhaging gunshot injury to the abdominal aorta

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    Endovascular stents have had a limited role in the management of trauma and vascular emergencies involving active hemorrhage. We describe a patient with delayed rupture of the infrarenal aorta after intra-abdominal sepsis caused the breakdown of a primary aortic repair. A stent-graft repair was performed, as concomitant injuries did not allow anterior access to the aorta. This report describes the successful endovascular repair of an actively hemorrhaging penetrating abdominal aortic injury. Endovascular approaches to aortic injuries may be valuable in settings where a hostile abdomen precludes traditional open repair

    Inception: Beginning a New Conversation about Communication Pedagogy and Scholarship

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    Drawing on past pedagogical and scholarly lines of inquiry, this article advances—in a dialogic form—several questions for future research and practice in areas of communication, teaching, and learning. The dialogic form of this article offers a metamessage, inviting colleagues to consider creative approaches to inquiry and collaboration in the 21st century. The ideas and questions presented in this essay serve to push the field beyond disciplinary silos, advance research and pedagogy about teaching and learning, and offer thought-provoking insight into what scholars and practitioners who explore communication, teaching, and learning can contribute to those inside and outside of our discipline

    Testing Newtonian Gravity with AAOmega: Mass-to-Light Profiles of Four Globular Clusters

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    Testing Newtonian gravity in the weak-acceleration regime is vital to our understanding of the nature of the gravitational interaction. It has recently been claimed that the velocity dispersion profiles of several globular clusters flatten out at large radii, reminiscent of galaxy rotation curves, even though globular clusters are thought to contain little or no dark matter. We investigate this claim, using AAOmega observations of four globular clusters, namely M22, M30, M53 and M68. M30, one such cluster that has had this claim made for its velocity dispersion, was included for comparison with previous studies. We find no statistically significant flattening of the velocity dispersion at large radii for any of our target clusters and therefore we infer the observed dynamics do not require that globular clusters are dark matter dominated, or a modification of gravity. Furthermore, by applying a simple dynamical model we determine the radial mass-to-light profiles for each cluster. The isothermal rotations of each cluster are also measured, with M22 exhibiting clear rotation, M68 possible rotation and M30 and M53 lacking any rotation, within the uncertainties.Comment: 7 pages, 4 figures and two tables. Accepted by MNRA

    A mass spectrometry-based approach to distinguish annular and specific lipid binding to membrane proteins

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    Membrane proteins engage in a variety of contacts with theirsurrounding lipids, but distinguishing between specifically boundlipids, and non-specific annular interactionsis a challenging problem. Applying native mass spectrometry to three membrane protein complexes with different lipid binding properties, we explore the ability of detergents to compete with lipids bound in different environments. We show that lipids in annular positions on the Presenilin Homologue protease are subject to constant exchange with detergent. Bycontrast,detergent-resistantlipids bound at the dimer interface in the Leucine transportershowdecreased koffrates in molecular dynamics simulations.Turning tothe lipid flippase MurJ, we findthat addition of the natural substrate lipid-II results in the formation of a 1:1 protein-lipid complex, where the lipid cannot be displaced by detergentfromthe highly protected active site.In summary, we distinguish annular from non-annular lipids based on their exchange rates in solution. [Abstract copyright: © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

    The deglacial history of 79N glacier and the Northeast Greenland Ice Stream

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    The Northeast Greenland Ice Stream (NEGIS) is the main artery for ice discharge from the northeast sector of the Greenland Ice Sheet (GrIS) to the North Atlantic. Understanding the past, present and future stability of the NEGIS with respect to atmospheric and oceanic forcing is of global importance as it drains around 17% of the GrIS and has a sea-level equivalent of 1.6 m. This paper reconstructs the deglacial and Holocene history of Nioghalvfjerdsbræ (or 79N Glacier); a major outlet of the NEGIS.At high elevation (>900 m asl) autochthonous blockfield, a lack of glacially moulded bedrock and pre LGM exposure ages point to a complex exposure/burial history extending back over half a million years. However, post Marine Isotope Stage 12, enhanced glacial erosion led to fjord incision and plateaux abandonment. Between 900 and 600 m asl the terrain is largely unmodified by glacial scour but post LGM erratics indicate the advection of cold-based ice through the fjord. In contrast, below ∼600 m asl Nioghalvfjerdsfjorden exhibits a geomorphological signal indicative of a warm-based ice stream operating during the last glacial cycle. Dated ice marginal landforms and terrain along the fjord walls show initial thinning rates were slow between ∼23 and 10 ka, but post-10 ka it is evident that Nioghalvfjerdsfjorden deglaciated extremely quickly with complete fjord deglaciation below ∼500 m asl between 10.0 and 8.5 ka.Both increasing air and ocean temperatures were pivotal in driving surface lowering and submarine melt during deglaciation, but the final withdrawal of ice through Nioghalvfjerdsfjorden was facilitated by the action of marine ice sheet instability. Our estimates show that thinning and retreat rates reached a maximum of 5.29 ma−1 and 613 ma−1, respectively, as the ice margin withdrew westwards. This would place the Early Holocene disintegration of this outlet of the NEGIS at the upper bounds of contemporary thinning and retreat rates seen both in Greenland and Antarctica. Combined with recent evidence of ice stream shutdown during the Holocene, as well as predictions of changing ice flow dynamics within downstream sections of the NEGIS catchment, this suggests that significant re-organisation of the terminal zone of the ice stream is imminent over the next century
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