229 research outputs found

    Surviving Winter: A Fitness-Based Explanation of Hoarding and Hibernation

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    The purpose of this essay is to provide a quantitative model of the fitness consequences of food hoarding. The model we develop explains storage and hibernation as intertemporal behaviors which maximize fitness. We use the term "fitness" to mean the number of surviving offspring.Center for Research on Economic and Social Theory, Department of Economics, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100944/1/ECON390.pd

    Deducing Implications of Fitness Maximization When a Tradeoff Exists Among Alternative Currencies

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    While the theory of natural selection posits that those behaviors maximizing reproductive success ("fitness") tend to survive, behavioral ecologists frequently explain observed behaviors as maximizing some "currency" on which fitness depends. A weakness of the approach is that reproductive success often depends on more than one currency and behaviors which augment one currency may reduce another. We explain how to deduce from the hypothesis of fitness maximization testable predictions. We expound the approach entirely in terms of two biological examples--a preliminary example involving flower replacement perennial and a more elaborate on involving over-winter hoarding by female mammals.Center for Research on Economic and Social Theory, Department of Economics, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100943/1/ECON389.pd

    Scavenger Receptors and Their Potential as Therapeutic Targets in the Treatment of Cardiovascular Disease

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    Scavenger receptors act as membrane-bound and soluble proteins that bind to macromolecular complexes and pathogens. This diverse supergroup of proteins mediates binding to modified lipoprotein particles which regulate the initiation and progression of atherosclerotic plaques. In vascular tissues, scavenger receptors are implicated in regulating intracellular signaling, lipid accumulation, foam cell development, and cellular apoptosis or necrosis linked to the pathophysiology of atherosclerosis. One approach is using gene therapy to modulate scavenger receptor function in atherosclerosis. Ectopic expression of membrane-bound scavenger receptors using viral vectors can modify lipid profiles and reduce the incidence of atherosclerosis. Alternatively, expression of soluble scavenger receptors can also block plaque initiation and progression. Inhibition of scavenger receptor expression using a combined gene therapy and RNA interference strategy also holds promise for long-term therapy. Here we review our current understanding of the gene delivery by viral vectors to cells and tissues in gene therapy strategies and its application to the modulation of scavenger receptor function in atherosclerosis

    Methodological approaches to determining the marine radiocarbon reservoir effect

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    The marine radiocarbon reservoir effect is an offset in 14C age between contemporaneous organisms from the terrestrial environment and organisms that derive their carbon from the marine environment. Quantification of this effect is of crucial importance for correct calibration of the <sup>14</sup>C ages of marine-influenced samples to the calendrical timescale. This is fundamental to the construction of archaeological and palaeoenvironmental chronologies when such samples are employed in <sup>14</sup>C analysis. Quantitative measurements of temporal variations in regional marine reservoir ages also have the potential to be used as a measure of process changes within Earth surface systems, due to their link with climatic and oceanic changes. The various approaches to quantification of the marine radiocarbon reservoir effect are assessed, focusing particularly on the North Atlantic Ocean. Currently, the global average marine reservoir age of surface waters, R(t), is c. 400 radiocarbon years; however, regional values deviate from this as a function of climate and oceanic circulation systems. These local deviations from R(t) are expressed as +R values. Hence, polar waters exhibit greater reservoir ages (δR = c. +400 to +800 <sup>14</sup>C y) than equatorial waters (δR = c. 0 <sup>14</sup>C y). Observed temporal variations in δR appear to reflect climatic and oceanographic changes. We assess three approaches to quantification of marine reservoir effects using known age samples (from museum collections), tephra isochrones (present onshore/offshore) and paired marine/terrestrial samples (from the same context in, for example, archaeological sites). The strengths and limitations of these approaches are evaluated using examples from the North Atlantic region. It is proposed that, with a suitable protocol, accelerator mass spectrometry (AMS) measurements on paired, short-lived, single entity marine and terrestrial samples from archaeological deposits is the most promising approach to constraining changes over at least the last 5 ky BP

    Primary accumulation in the Soviet transition

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    The Soviet background to the idea of primary socialist accumulation is presented. The mobilisation of labour power and of products into public sector investment from outside are shown to have been the two original forms of the concept. In Soviet primary accumulation the mobilisation of labour power was apparently more decisive than the mobilisation of products. The primary accumulation process had both intended and unintended results. Intended results included bringing most of the economy into the public sector, and industrialisation of the economy as a whole. Unintended results included substantial economic losses, and the proliferation of coercive institutions damaging to attainment of the ultimate goal - the building of a communist society

    Allocation under dictatorship : research in Stalin’s archives

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    We survey recent research on the Soviet economy in the state, party, and military archives of the Stalin era. The archives have provided rich new evidence on the economic arrangements of a command system under a powerful dictator including Stalin’s role in the making of the economic system and economic policy, Stalin’s accumulation objectives and the constraints that limited his power to achieve them, the limits to administrative allocation, the information flows and incentives that governed the behavior of economic managers, the scope and significance of corruption and market-oriented behavior, and the prospects for economic reform

    The mimetic politics of lone-wolf terrorism

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    Written at a time of crisis in the project of social and political modernity, Fyodor Dostoevsky’s 1864 novel Notes from Underground offers an intriguing parallel for the twenty-first century lone-wolf; it portrays an abject, outcast, spiteful unnamed anti-hero boiling with rage, bitter with resentment and on the verge of radicalisation. A Girardian reading of the poetic truths contained in Dostoevsky’s work is able to provide important keys to explain the contemporary transformation from ‘fourth-wave’ religious terrorism to ‘fifth-wave’ lone-wolf terrorism. Such a reading argues that it is mimetic rivalry – rather than much-trumpeted forms of religious violence or cultural differences – that fuels the triangular relation between governments, terrorists and civilian victims at heart of terrorist acts. This approach is further able to blend social inquiry with an account of the individual, in fact anthropological, conditions of lone-wolf terrorism by tracing the globalisation of resentment and the individualisation of violence to the hyper-mimeticism characterising the globalisation of late modernity. Finally, a mimetic reading of ‘fifth-wave’ terrorism accounts for the turbulence of a global politics in which victimhood and scapegoating no longer have the ability to stabilise social order and warns against a future where violence proliferates and escalates unchecked

    Pleurotomy with subxyphoid pleural drain affords similar effects to pleural integrity in pulmonary function after off-pump coronary artery bypass graft

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    Background: Exacerbation of pulmonary dysfunction has been reported in patients receiving a pleural drain inserted through the intercostal space in comparison to patients with an intact pleura undergoing coronary artery bypass grafting (CABG). Evidence suggests that shifting the site of pleural drain insertion to the subxyphoid position minimizes chest wall trauma and preserves respiratory function in the early postoperative period. the aim of this study was to compare the pulmonary function parameters, clinical outcomes, and pain score between patients undergoing pleurotomy with pleural drain placed in the subxyphoid position and patients with intact pleural cavity after off-pump CABG (OPCAB) using left internal thoracic artery (LITA).Methods: Seventy-one patients were allocated into two groups: I (n = 38 open left pleural cavity and pleural drain inserted in the subxyphoid position); II (n = 33 intact pleural cavity). Pulmonary function tests and clinical parameters were recorded preoperatively and on postoperative days (POD) 1, 3 and 5. Arterial blood gas analysis and shunt fraction were evaluated preoperatively and in POD1. Pain score was assessed on POD1. To monitor pleural effusion and atelectasis chest radiography was performed routinely 1 day before operation and until POD5.Results: in both groups a significant impairment was found in lung function parameters until on POD5. However, no significant difference in forced vital capacity and forced expiratory volume in 1 second were seen between groups. A significant decrease in partial pressure of arterial oxygen and an increase in shunt fraction values were observed on POD1 in both groups, but no statistical difference was found when the groups were compared. Pleural effusion and atelectasis until on POD5 were similar in both groups. There were no statistical differences in pain score, duration of mechanical ventilation and postoperative hospital stay between groups.Conclusion: Subxyphoid insertion of pleural drain provides similar effects to preserved pleural integrity in pulmonary function, clinical outcomes, and thoracic pain after OPCAB. Therefore, our results support the hypothesis that once pleural cavities are incidentally or purposely opened during LITA dissection, subxyphoid placement of the pleural drain is recommended.Universidade Federal de São Paulo, Escola Paulista Med, Pirajussara Hosp, Dept Med,Cardiol Discipline, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo Hosp, Dept Med,Cardiol Discipline, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Physiotherapy Sch, Dept Human Movement Sci, BR-11060001 Santos, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo Hosp, Dept Med,Pneumol Discipline, BR-04039002 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Pirajussara Hosp, Dept Med,Cardiovasc Surg Discipline, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo Hosp, Dept Med,Cardiovasc Surg Discipline, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Pirajussara Hosp, Dept Med,Cardiol Discipline, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo Hosp, Dept Med,Cardiol Discipline, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Physiotherapy Sch, Dept Human Movement Sci, BR-11060001 Santos, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo Hosp, Dept Med,Pneumol Discipline, BR-04039002 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Pirajussara Hosp, Dept Med,Cardiovasc Surg Discipline, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, São Paulo Hosp, Dept Med,Cardiovasc Surg Discipline, BR-04024002 São Paulo, BrazilWeb of Scienc

    In silico design and biological evaluation of a dual specificity kinase inhibitor targeting cell cycle progression and angiogenesis

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    Methodology: We have utilized a rational in silico-based approach to demonstrate the design and study of a novel compound that acts as a dual inhibitor of vascular endothelial growth factor receptor 2 (VEGFR2) and cyclin-dependent kinase 1 (CDK1). This compound acts by simultaneously inhibiting pro-Angiogenic signal transduction and cell cycle progression in primary endothelial cells. JK-31 displays potent in vitro activity against recombinant VEGFR2 and CDK1/cyclin B proteins comparable to previously characterized inhibitors. Dual inhibition of the vascular endothelial growth factor A (VEGF-A)-mediated signaling response and CDK1-mediated mitotic entry elicits anti-Angiogenic activity both in an endothelial-fibroblast co-culture model and a murine ex vivo model of angiogenesis
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