963 resultados para shock oscillation
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This PhD thesis is an empirical research project in the field of modern Polish history. The thesis focuses on Solidarity, the Network and the idea of workers’ self-management. In addition, the thesis is based on an in-depth analysis of Solidarity archival material. The Solidarity trade union was born in August 1980 after talks between the communist government and strike leaders at the Gdansk Lenin Shipyards. In 1981 a group called the Network rose up, due to cooperation between Poland’s great industrial factory plants. The Network grew out of Solidarity; it was made up of Solidarity activists, and the group acted as an economic partner to the union. The Network was the base of a grass-roots, nationwide workers’ self-management movement. Solidarity and the self-management movement were crushed by the imposition of Martial Law in December 1981. Solidarity revived itself immediately, and the union created an underground society. The Network also revived in the underground, and it continued to promote self-management activity where this was possible. When Solidarity regained its legal status in April 1989, workers’ self-management no longer had the same importance in the union. Solidarity’s new politico-economic strategy focused on free markets, foreign investment and privatization. This research project ends in July 1990, when the new Solidarity-backed government enacted a privatization law. The government decided to transform the property ownership structure through a centralized privatization process, which was a blow for supporters of workers’ self-management. This PhD thesis provides new insight into the evolution of the Solidarity union from 1980-1990 by analyzing the fate of workers’ self-management. This project also examines the role of the Network throughout the 1980s. There is analysis of the important link between workers’ self-management and the core ideas of Solidarity. In addition, the link between political and economic reform is an important theme in this research project. The Network was aware that authentic workers’ self-management required reforms to the authoritarian political system. Workers’ self-management competed against other politico-economic ideas during the 1980s in Poland. The outcome of this competition between different reform concepts has shaped modern-day Polish politics, economics and society.
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We analyze the causal structure of the two-dimensional (2D) reduced background used in the perturbative treatment of a head-on collision of two D-dimensional Aichelburg–Sexl gravitational shock waves. After defining all causal boundaries, namely the future light-cone of the collision and the past light-cone of a future observer, we obtain characteristic coordinates using two independent methods. The first is a geometrical construction of the null rays which define the various light cones, using a parametric representation. The second is a transformation of the 2D reduced wave operator for the problem into a hyperbolic form. The characteristic coordinates are then compactified allowing us to represent all causal light rays in a conformal Carter–Penrose diagram. Our construction holds to all orders in perturbation theory. In particular, we can easily identify the singularities of the source functions and of the Green’s functions appearing in the perturbative expansion, at each order, which is crucial for a successful numerical evaluation of any higher order corrections using this method.
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International audience
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A novel method to measure oxidative stress resulting from exhaustive exercise in rats is presented. In this new procedure we evaluated the erythrocyte antioxidant enzymes, catalase ( CAT) and glutathione reductase (GR), the plasma oxidative attack markers, reactive carbonyl derivatives (RCD) and thiobarbituric reactive substances (TBARS). Muscular tissue damage was evaluated by monitoring plasma creatine kinase (CK) and plasma taurine ( Tau) concentrations. Also, we monitored total sulphydryl groups (TSG) and uric acid (UA), and the level of the 70 kDa heat shock protein (HSP70) in leukocytes as a marker of oxidative stress. In the study we found a correspondence between erythrocyte CAT and GR activities and leukocyte HSP70 levels, principally 3 h after the acute exercise, and this suggested an integrated mechanism of antioxidant defense. The increase in levels of plasma Tau was coincident with the increasing plasma levels of CK and TBARS, principally after two hours of exercise. Thus tissue damage occurred before the expression of any anti-oxidant system markers and the monitoring of Tau, CK or TBARS may be important for the estimation of oxidative stress during exhaustive exercise. Furthermore, the integrated analyses could be of value in a clinical setting to quantify the extent of oxidative stress risk and reduce the need to perform muscle biopsies as a tool of clinical evaluation.
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Presentamos el caso de una paciente atendida en urgencias del centro de salud por un cuadro clínico de shock anafiláctico desencadenado tras la ingesta de manzana y realización posterior de ejercicio físico. En alergia a alimentos, hay que tener presente que en algunas personas es necesaria la presencia de determinados cofactores como el ejercicio físico o la ingesta de determinados fármacos como los AINEs para que suceda una reacción alérgica. Se sospecha que el mecanismo responsable consiste en que aceleren la absorción del alimento en el intestino y así lleguen a modular la severidad de los síntomas. Por este motivo cuando las LTP (proteína de transferencia de lípidos) están implicadas, si los cofactores no se detectan y previenen, pueden representar un serio riesgo para el desarrollo de episodios de anafilaxia severos o fatales.
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This paper analyses the influence of different atmospheric circulation indices on the multi-scalar drought variability across Europe by using the Standardized Precipitation Evapotranspiration Index (SPEI). The monthly circulation indices used in this study include the North Atlantic oscillation (NAO), the East Atlantic (EA), the Scandinavian (SCAN) and the East Atlantic-Western Russia (EA-WR) patterns, as well as the recently published Westerly Index (WI), defined as the persistence of westerly winds over the eastern north Atlantic region. The results indicate that European drought variability is better explained by the station-based NAO index and the WI than by any other combination of circulation indices. In northern and central Europe the variability of drought severity for different seasons and time-scales is strongly associated with the WI. On the contrary, the influence of the NAO on southern Europe droughts is stronger than that exerted by the WI. The correlation patterns of the NAO and WI with the SPEI show a spatial complementarity in shaping drought variability across Europe. Lagged correlations of the NAO and WI with the SPEI also indicate enough skill of both indices to anticipate drought severity several months in advance. As long as instrumental series of the NAO and WI are available, their combined use would allow inferring European drought variability for the last two centuries and improve the calibration and interpretation of paleoclimatic proxies associated with drought.
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In the Southern Hemisphere (SH) polar region, satellite observations reveal a significant upper-mesosphere cooling and a lower-thermosphere warming during warm ENSO events in December. An opposite pattern is observed in the tropical mesopause region. The observed upper-mesosphere cooling agrees with a climate model simulation. Analysis of the simulation suggests that enhanced planetary wave (PW) dissipation in the Northern Hemisphere (NH) high-latitude stratosphere during El Nino strengthens the Brewer-Dobson circulation and cools the equatorial stratosphere. This increases the magnitude of the SH stratosphere meridional temperature gradient and thus causes the anomalous stratospheric easterly zonal wind and early breakdown of the SH stratospheric polar vortex. The resulting perturbation to gravity wave (GW) filtering causes anomalous SH mesospheric eastward GW forcing and polar upwelling and cooling. In addition, constructive inference of ENSO and quasi-biennial oscillation (QBO) could lead to stronger stratospheric easterly zonal wind anomalies at the SH high latitudes in November and December and early breakdown of the SH stratospheric polar vortex during warm ENSO events in the easterly QBO phase (defined by the equatorial zonal wind at similar to 25 hPa). This would in turn cause much more SH mesospheric eastward GW forcing and much colder polar temperatures, and hence it would induce an early onset time of SH summer polar mesospheric clouds (PMCs). The opposite mechanism occurs during cold ENSO events in the westerly QBO phase. This implies that ENSO together with QBO could significantly modulate the breakdown time of SH stratospheric polar vortex and the onset time of SH PMC.
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Grapevine is an extremely important crop worldwide.In southern Europe, post-flowering phases of the growth cycle can occur under high temperatures, excessive light, and drought conditions at soil and/or atmospheric level. In this study, we subjected greenhouse grown grapevine, variety Aragonez, to two individual abiotic stresses, water deficit stress(WDS), and heat stress (HS). The adaptation of plants to stress is a complex response triggered by cascades of molecular net works involved in stress perception, signal transduction, and the expression of specific stress-related genes and metabolites. Approaches such as array-based transcript profiling allow assessing the expression of thousands of genes in control and stress tissues. Using microarrays, we analyzed the leaf transcriptomic profile of the grapevine plants. Photosynthesis measurements verified that the plants were significantly affected by the stresses applied. Leaf gene expression was obtained using a high-throughput transcriptomic grapevine array, the 23K custom-made Affymetrix Vitis GeneChip. We identified 1,594 genes as differentially expressed between control and treatments and grouped them into ten major functional categories using MapMan software. The transcriptome of Aragonez was more significantly affected by HS when compared with WDS. The number of genes coding for heat-shock proteins and transcription factors expressed solely in response to HS suggesting their expression as unique signatures of HS. However, across-talk between the response pathways to both stresses was observed at the level of AP2/ERF transcription factors.
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Cardiogenic shock (CS) has a poor prognosis. The heterogeneity in the mortality through different subgroups suggests that some factors can be useful to perform risk stratification and guide management. We aimed to find predictors of in-hospital mortality in these patients. We analyzed all cases of cardiogenic shock due to medical conditions admitted in our intensive acute cardiovascular care unity from November 2010 till November 2015. Clinical, biochemical and hemodynamic variables were registered, as was the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile at 24 h of CS diagnosis. From a total of 281 patients, 28 died within the first 24 h and were not included in the analysis. A total of 253 patients survived the first 24 h, mean age was 68.8 ± 14.4 years, and 174 (68.8%) were men. Etiologies: acute coronary syndrome 146 (57.7%), acute heart failure 60 (23.7%), arrhythmias 35 (13.8%), and others 12 (4.8%). A total of 91 patients (36.0%) died during hospitalization. We found the following independent predictors of in-hospital mortality: age (odds ratio [OR] 1.032, 95% confidence interval [CI] 1.003–1.062), blood glucose (OR 1.004, 95% CI 1.001–1.008), heart rate (OR 1.014, 95% CI 1.001–1.028), and INTERMACS profile (OR 0.168, 95% CI 0.107–0.266). In patients with CS the INTERMACS profile at 24 h of diagnosis was associated with higher in-hospital mortality. This and other prognostic variables (age, blood glucose, and heart rate) may be useful for risk stratification and to select appropriate medical or invasive interventions.
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Le stress joue un rôle important dans le maintien de la qualité de vie quotidienne. Une exposition à une situation stressante peut causer divers désordres neuropsychiatriques du cerveau qui sont associés avec des problèmes liés au sommeil, à la dépression, à des problèmes digestifs et à des troubles de l’alimentation. Les traitements de ces troubles liés au stress sont très coûteux à travers le monde. De nos jours, des considérations importantes ont été soulevées afin de trouver des moyens appropriés pour la prévention plutôt que de dépenser ultérieurement plus de budget sur les traitements. De cette façon, l’étude et l’expérimentation sur les animaux des troubles liés au stress sont l’un des moyens les plus fiables pour atteindre une compréhension plus profonde des problèmes liés au stress. Ce projet visait à révéler la modulation des potentiels de champ locaux (LFP) lors de la consommation de sucrose dans deux conditions englobant la condition de contrôle non-stressante et celle stressante d’un choc électrique aiguë à la patte dans le cortex préfrontal médian (CPFm) du cerveau de rat. Le CPFm est une structure importante dans la réponse au stress et à l’anxiété par l’interaction avec l’axe hypothalamique-pituitaire surrénale (HPA). Les résultats de ce projet ont révélé que la plupart des coups de langue se sont produits dans les 15 premières minutes de l’accès à une solution de sucrose autant pour la condition contrôle non-stressante que pour la condition stressante. En outre, le stress aigu d’un choc à la patte affecte de manière significative la consommation horaire de sucrose en diminuant le volume de la consommation. Les résultats ont également révélé une présence importante du rythme thêta dans le CPFm pendant la condition de base et pendant l’ingestion de sucrose dans les deux conditions. De plus, les résultats ont montré une diminution de puissance des bandes delta et thêta lors des initiations de léchage du sucrose. Ce projet conduit à des informations détaillées sur les propriétés électrophysiologiques du cortex infra-limbique (IL) du CPFm en réponse à l’exposition à des conditions de stress et de l’apport d’une solution de sucrose. Ce projet permet également de mieux comprendre les mécanismes neurophysiologiques des neurones du CPFm en réponse à l’exposition à une condition stressante suivie d’apport de sucrose. Ce projet a également permis de confirmer les effets anorexigènes du stress et suggèrent également que la synchronisation neuronale dans le cortex IL peut jouer un rôle dans le comportement de léchage et sa désynchronisation pendant le léchage après une exposition à des conditions stressantes.
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Rhizobia are important soil bacteria due to their ability to establish nitrogen-fixing symbioses with legume plants. In this dual lifestyle, as free-living bacteria or as plant symbiont, rhizobia are often exposed to different environmental stresses. The present chapter overviews the current knowledge on the heat shock response of rhizobia, highlighting how these large genome bacteria respond to heat from a transcriptional point of view. Response to heat shock in rhizobia involves genome wide changes in the transcriptome that may affect more than 30% of the genome and involve all replicons. In addition to the expected upregulation of genes already known to be involved in stress response (dnaK, groEL, ibpA, clpB), the reports on the heat shock response in rhizobia also showed particular aspects of stress response in these resourceful bacteria. The transcriptional response to heat in rhizobia includes the overexpression of a large number of genes involved in transcription and carbohydrate transport and metabolism. Additional studies are needed in order to better understand the transcriptional regulation of stress response in bacteria with large genomes.
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Soil salinity affects rhizobia both as free-living bacteria and in symbiosis with the host. The aim of this study was to examine the transcriptional response of the Lotus microsymbiont Mesorhizobium loti MAFF303099 to salt shock. Changes in the transcriptome of bacterial cells subjected to a salt shock of 10% NaCl for 30 min were analyzed. From a total of 7231 protein-coding genes, 385 were found to be differentially expressed upon salt shock, among which 272 were overexpressed. Although a large number of overexpressed genes encode hypothetical proteins, the two most frequently represented COG categories are "defense mechanisms" and "nucleotide transport and metabolism". A significant number of transcriptional regulators and ABC transporters genes were upregulated. Chemotaxis and motility genes were not differentially expressed. Moreover, most genes previously reported to be involved in salt tolerance were not differentially expressed. The transcriptional response to salt shock of a rhizobium with low ability to grow under salinity conditions, but enduring a salinity shock, may enlighten us concerning salinity stress response mechanisms.
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Respostas fisiológicas ao estresse do peixe de águas tépidas matrinxã (Brycon amazonicus) submetido à queda brusca de temperatura.