753 resultados para Capacity limits


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Background Pulmonary function tests (PFT), particularly spirometry and lung diffusing capacity for carbon monoxide (DL(CO)), have been considered useful methods for the detection of the progression of interstitial asbestos abnormalities as indicated by high-resolution computed tomography (HRCT). However, it is currently unknown which of these two tests correlates best with anatomical changes over time. Methods In this study, we contrasted longitudinal changes (3-9 years follow-up) in PFTs at rest and during exercise with interstitial abnormalities evaluated by HRCT in 63 ex-workers with mild-to-moderate asbestosis. Results At baseline, patients presented with low-grade asbestosis (Huuskonen classes I-II), and most PFT results were within the limits of normality. In the follow-up, most subjects had normal spirometry, static lung volumes and arterial blood gases. In contrast, frequency of DL(CO) abnormalities almost doubled (P < 0.05). Twenty-three (36.5%) subjects increased the interstitial marks on HRCT. These had significantly larger declines in DL(CO) compared to patients who remained stable (0.88 vs. 0.31 ml/min/mm Hg/year and 3.5 vs. 1.2%/year, respectively; P < 0.05). In contrast, no between-group differences were found for the other functional tests, including spirometry (P > 0.05). Conclusions These data demonstrate that the functional consequences of progression of HRCT abnormalities in mild-to-moderate asbestosis are better reflected by decrements in DL(CO) than by spirometric changes. These results might have important practical implications for medico-legal evaluation of this patient population. Am. J. Ind. Med. 54:185-193, 2011. (c) 2010 Wiley-Liss, Inc.

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Idiopathic pulmonary fibrosis is a distinctive, usually fatal, type of chronic fibrosing interstitial pneumonia of unknown cause that increases in prevalence with advanced age, characterized by failure of alveolar re-epithelization and progressive scar formation. Recently, limitation of the replicative capacity of tissues determined by telomerase/apoptosis balance has been implicated in pathogenesis of age-related diseases. In this study, we validated the importance of the expression of type 2 alveolar epithelial cells telomerase protein and studied the relationships between telomerase and apoptosis in early remodeling of usual interstitial pneumonia. We determined type 2 alveolar epithelial cells density, telomerase expression, and apoptosis in surgical lung biopsies from 24 patients with usual interstitial pneumonia, and in normal lung tissues from 18 subjects. We used immunohistochemistry, deoxynucleotidyl transferase method of end labeling, electron microscopy, and histomorphometry to evaluate the amount of type 2 alveolar epithelial cells staining for surfactant-A, telomerase, and in situ detection of apoptotic cells. Unaffected areas of usual interstitial pneumonia and normal lung tissue had similar densities of type 2 alveolar epithelial cells, but a significant minor subpopulation of type 2 alveolar epithelial cells was telomerase positive and a large population was telomerase negative. A significant inverse association was found between low type 2, alveolar. epithelial cell telomerase expression and high apoptosis in unaffected areas of usual interstitial pneumonia. Although type 2 alveolar epithelial cell telomerase expression was higher than apoptosis in NLT group, no significant association was found between them. Electron microscopy confirmed epithelial apoptosis, alveolar collapse, and initial fibroplasia. We conclude that abnormal type 2 alveolar epithelial cells telomerase/apoptosis balance may reduce alveolar epithelial regenerative capacity, thus contributing to the early remodeling response in usual interstitial pneumonia. (C) 2010 Elsevier Inc. All rights reserved.

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Essential hypertension is a common disorder, associated with increased endothelin-l-mediated vasoconstrictor tone at rest. We hypothesized that increased vasoconstrictor activity of endothelin-1 might explain why the normal decrease in peripheral vascular resistance in response to exercise is attenuated in hypertensive patients. Therefore, we investigated the effect of endothelin A (ETA) receptor blockade on the vasodilator response to handgrip exercise. Forearm blood flow responses to handgrip exercise (15%, 30%, and 45% of maximum voluntary contraction) were assessed in hypertensive patients and matched normotensive subjects, before and after intra-arterial infusions of the ETA receptor antagonist BQ-123; a control dilator, hydralazine; and placebo (saline). Preinfusion (baseline) vasodilation in response to exercise was significantly attenuated at each workload in hypertensive patients compared with normotensive subjects. Intra-arterial infusions of hydralazine and saline did not increase the vasodilator response to exercise in either hypertensives or normotensives at any workload. The vasodilator response to exercise was markedly enhanced after BQ-123 at the 2 higher workloads in hypertensives (157 +/- 48%, P < 0.01; 203 &PLUSMN; 58%, P < 0.01) but not in normotensives. This suggests that the impaired vasodilator response to exercise in hypertensive patients is, at least in part, a functional limitation caused by endogenous ETA receptor-mediated vasoconstriction. Treatment with endothelin receptor antagonists may, therefore, increase exercise capacity in essential hypertension.

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Modeling the fundamental performance limits of Wireless Sensor Networks (WSNs) is of paramount importance to understand their behavior under worst-case conditions and to make the appropriate design choices. In that direction this paper contributes with an analytical methodology for modeling cluster-tree WSNs where the data sink can either be static or mobile. We assess the validity and pessimism of analytical model by comparing the worst-case results with the values measured through an experimental test-bed based on Commercial-Off- The-Shelf (COTS) technologies, namely TelosB motes running TinyOS.

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This paper studies the fundamental operational limits of a class of Gaussian multicast channels with an interference setting. In particular, the paper considers two base stations multicasting separate messages to distinct sets of users. In the presence of channel state information at the transmitters and at the respective receivers, the capacity region of the Gaussian multicast channel with interference is characterized to within one bit. At the crux of this result is an extension to the multicast channel with interference of the Han-Kobayashi or the Chong-Motani-Garg achievable region for the interference channel.

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Since the 1980s in Western Europe, centralized states' control over subnational territories has been deeply affected by processes of Europeanization and regionalization. These changes have raised the issue of state territorial restructuring in a particular fashion: what capacity have formerly centralized states retained to steer and control subnational territories? The article draws on Mann's concept of infrastructural power, which refers to the state's capacity to exercise control and implement political decisions over the national territory. The article applies the two main operationalizations of the concept, namely the capability of the state to exercise control and the weight of the state in the subnational territories. Empirically, the article focuses on the French state in two policy sectors (education and housing). Although France is a most likely case, this article challenges this expectation, and shows the limits of the French state's infrastructural power over the subnational territories since the late 1980s.

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BACKGROUND: Reactive oxygen species production increases during aging, whereas protective mechanisms such as heat shock proteins (HSPs) or antioxidant capacity are depressed. Physical activity has been hypothesized to provide protection against oxidative damage during aging, but results remain controversial. This study aimed to investigate the effect of different levels of physical activity during aging on Hsp72 expression and systemic oxidative stress at rest and in response to maximal exercise. METHODS: Plasma antioxidant capacity (Trolox equivalent antioxidant capacity, TEAC), thiobarbituric acid-reactive species (TBARS), advanced oxidized proteins products (AOPP), and Hsp72 expression in leukocytes were measured before and after maximal exercise testing in 32 elderly persons (aged 73.2 years), who were assigned to two different groups depending on their level of physical activity during the past 12 months (OLow = moderate to low level; OHigh = higher level). RESULTS: The OHigh group showed higher aerobic fitness and TEAC (both representing 120% of OLow values) as well as lower oxidative damage (50% of OLow values) and Hsp72 expression. Exercise led to a lower increase in oxidative damage in the OHigh group. Aerobic fitness was positively correlated with TEAC and negatively with lipid peroxidation (TBARS). Hsp72 expression was negatively correlated with TEAC but positively correlated with TBARS levels. CONCLUSIONS: The key finding of this study is that, in people aged 60 to 90 years, long-term high level of physical activity preserved antioxidant capacity and limited oxidative damage accumulation. It also downregulated Hsp72 expression, an adaptation potentially resulting from lower levels of oxidative damage.

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Purpose of the evaluation This is a scheduled standard mid-term evaluation (MTR) of a UNDP implemented GEF LDCF co-financed project. It is conducted by a team of an international and a national independent evaluator. The objective of the MTR, as set out in the Terms of Reference (TORs; Annex 1), is to provide an independent analysis of the progress of the project so far. The MTR aims to:  identify potential project design problems,  assess progress towards the achievement of the project objective and outcomes,  identify and document lessons learned (including lessons that might improve design and implementation of other projects, including UNDP-GEF supported projects), and  make recommendations regarding specific actions that should be taken to improve the project. The MTR is intended to assess signs of project success or failure and identify the necessary changes to be made. The project commenced its implementation in the first half of 2010 with the recruitment of project staff. According to the updated project plan, it is due to close in July 201410 with operations scaling down in December 2013 due to funding limits. Because of a slow implementation start, the mid-term evaluation was delayed to July 201311 The intended target audience of the evaluation are:  The project team and decision makers in the INGRH  The GEF and UNFCCC Operational Focal Points  The project partners and beneficiaries  UNDP in Cape Verde as well as the regional and headquarter (HQ) office levels  The GEF Secretariat.

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The soil water available to crops is defined by specific values of water potential limits. Underlying the estimation of hydro-physical limits, identified as permanent wilting point (PWP) and field capacity (FC), is the selection of a suitable method based on a multi-criteria analysis that is not always clear and defined. In this kind of analysis, the time required for measurements must be taken into consideration as well as other external measurement factors, e.g., the reliability and suitability of the study area, measurement uncertainty, cost, effort and labour invested. In this paper, the efficiency of different methods for determining hydro-physical limits is evaluated by using indices that allow for the calculation of efficiency in terms of effort and cost. The analysis evaluates both direct determination methods (pressure plate - PP and water activity meter - WAM) and indirect estimation methods (pedotransfer functions - PTFs). The PTFs must be validated for the area of interest before use, but the time and cost associated with this validation are not included in the cost of analysis. Compared to the other methods, the combined use of PP and WAM to determine hydro-physical limits differs significantly in time and cost required and quality of information. For direct methods, increasing sample size significantly reduces cost and time. This paper assesses the effectiveness of combining a general analysis based on efficiency indices and more specific analyses based on the different influencing factors, which were considered separately so as not to mask potential benefits or drawbacks that are not evidenced in efficiency estimation.

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Résumé La responsabilité d'un expert chargé d'apprécier la capacité érectile d'un prévenu est importante, car la peine infligée par le tribunal peut dépendre de ses conclusions. Sa tâche est en plus ardue car les procédés d'investigations de la fonction érectile ont tous des limites. Malgré toutes ces limites qui sont décrites dans cet article, l'expert peut aider à la recherche de la vérité comme les auteurs le démontrent. Summary The responsability of the expert in charge to appreciate the erectile capacity of an accused is considerable, as the sentence inflicted by the Tribunal could depend directly on his conclusions. His duty is harder as all the investigation procedures of the erectile functions have limits. Despite these limits, described in this article, the expert can help to discover the truth, as demonstrated by the authors.

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Ly49A is an inhibitory receptor, which counteracts natural killer (NK) cell activation on the engagement with H-2D(d) (D(d)) MHC class I molecules (MHC-I) on target cells. In addition to binding D(d) on apposed membranes, Ly49A interacts with D(d) ligand expressed in the plane of the NK cells' membrane. Indeed, multivalent, soluble MHC-I ligand binds inefficiently to Ly49A unless the NK cells' D(d) complexes are destroyed. However, it is not known whether masked Ly49A remains constitutively associated with cis D(d) also during target cell interaction. Alternatively, it is possible that Ly49A has to be unmasked to significantly interact with its ligand on target cells. These two scenarios suggest distinct roles of Ly49A/D(d) cis interaction for NK cell function. Here, we show that Ly49A contributes to target cell adhesion and efficiently accumulates at synapses with D(d)-expressing target cells when NK cells themselves lack D(d). When NK cells express D(d), Ly49A no longer contributes to adhesion, and ligand-driven recruitment to the cellular contact site is strongly reduced. The destruction of D(d) complexes on NK cells, which unmasks Ly49A, is necessary and sufficient to restore Ly49A adhesive function and recruitment to the synapse. Thus, cis D(d) continuously sequesters a considerable fraction of Ly49A receptors, preventing efficient Ly49A recruitment to the synapse with D(d)+ target cells. The reduced number of Ly49A receptors that can functionally interact with D(d) on target cells explains the modest inhibitory capacity of Ly49A in D(d) NK cells. This property renders Ly49A NK cells more sensitive to react to diseased host cells.

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Electricity is a strategic service in modern societies. Thus, it is extremely important for governments to be able to guarantee an affordable and reliable supply, which depends to a great extent on an adequate expansion of the generation and transmission capacities. Cross- border integration of electricity markets creates new challenges for the regulators, since the evolution of the market is now influenced by the characteristics and policies of neighbouring countries. There is still no agreement on why and how regions should integrate their electricity markets. The aim of this thesis is to improve the understanding of integrated electricity markets and how their behaviour depends on the prevailing characteristics of the national markets and the policies implemented in each country. We developed a simulation model to analyse under what circumstances integration is desirable. This model is used to study three cases of interconnection between two countries. Several policies regarding interconnection expansion and operation, combined with different generation capacity adequacy mechanisms, are evaluated. The thesis is composed of three papers. The first paper presents a detailed description of the model and an analysis of the case of Colombia and Ecuador. It shows that market coupling can bring important benefits, but the relative size of the countries can lead to import dependency issues in the smaller country. The second paper compares the case of Colombia and Ecuador with the case of Great Britain and France. These countries are significantly different in terms of electricity sources, hydro- storage capacity, complementarity and demand growth. We show that complementarity is essential in order to obtain benefits from integration, while higher demand growth and hydro- storage capacity can lead to counterintuitive outcomes, thus complicating policy design. In the third paper, an extended version of the model presented in the first paper is used to analyse the case of Finland and its interconnection with Russia. Different trading arrangements are considered. We conclude that unless interconnection capacity is expanded, the current trading arrangement, where a single trader owns the transmission rights and limits the flow during peak hours, is beneficial for Finland. In case of interconnection expansion, market coupling would be preferable. We also show that the costs of maintaining a strategic reserve in Finland are justified in order to limit import dependency, while still reaping the benefits of interconnection. In general, we conclude that electricity market integration can bring benefits if the right policies are implemented. However, a large interconnection capacity is only desirable if the countries exhibit significant complementarity and trust each other. The outcomes of policies aimed at guaranteeing security of supply at a national level can be quite counterintuitive due to the interactions between neighbouring countries and their effects on interconnection and generation investments. Thus, it is important for regulators to understand these interactions and coordinate their decisions in order to take advantage of the interconnection without putting security of supply at risk. But it must be taken into account that even when integration brings benefits to the region, some market participants lose and might try to hinder the integration process. -- Dans les sociétés modernes, l'électricité est un service stratégique. Il est donc extrêmement important pour les gouvernements de pouvoir garantir la sécurité d'approvisionnement à des prix abordables. Ceci dépend en grande mesure d'une expansion adéquate des capacités de génération et de transmission. L'intégration des marchés électriques pose des nouveaux défis pour les régulateurs, puisque l'évolution du marché est maintenant influencée par les caractéristiques et les politiques des pays voisins. Il n'est pas encore claire pourquoi ni comment les marches électriques devraient s'intégrer. L'objectif de cette thèse est d'améliorer la compréhension des marchés intégrés d'électricité et de leur comportement en fonction des caractéristiques et politiques de chaque pays. Un modèle de simulation est proposé pour étudier les conditions dans lesquelles l'intégration est désirable. Ce modèle est utilisé pour étudier trois cas d'interconnexion entre deux pays. Plusieurs politiques concernant l'expansion et l'opération de l'interconnexion, combinées avec différents mécanismes de rémunération de la capacité, sont évalués. Cette thèse est compose de trois articles. Le premier présente une description détaillée du modèle et une analyse du cas de la Colombie et de l'Equateur. Il montre que le couplage de marchés peut amener des bénéfices importants ; cependant, la différence de taille entre pays peut créer des soucis de dépendance aux importations pour le pays le plus petit. Le second papier compare le cas de la Colombie et l'Equateur avec le cas de la Grande Bretagne et de la France. Ces pays sont très différents en termes de ressources, taille des réservoirs d'accumulation pour l'hydro, complémentarité et croissance de la demande. Nos résultats montrent que la complémentarité joue un rôle essentiel dans l'obtention des bénéfices potentiels de l'intégration, alors qu'un taux élevé de croissance de la demande, ainsi qu'une grande capacité de stockage, mènent à des résultats contre-intuitifs, ce qui complique les décisions des régulateurs. Dans le troisième article, une extension du modèle présenté dans le premier article est utilisée pour analyser le cas de la Finlande et de la Russie. Différentes règles pour les échanges internationaux d'électricité sont considérées. Nos résultats indiquent qu'à un faible niveau d'interconnexion, la situation actuelle, où un marchand unique possède les droits de transmission et limite le flux pendant les heures de pointe, est bénéfique pour la Finlande. Cependant, en cas d'expansion de la capacité d'interconnexion, «market coupling» est préférable. préférable. Dans tous les cas, la Finlande a intérêt à garder une réserve stratégique, car même si cette politique entraine des coûts, elle lui permet de profiter des avantages de l'intégration tout en limitant ca dépendance envers les importations. En général, nous concluons que si les politiques adéquates sont implémentées, l'intégration des marchés électriques peut amener des bénéfices. Cependant, une grande capacité d'interconnexion n'est désirable que si les pays ont une complémentarité importante et il existe une confiance mutuelle. Les résultats des politiques qui cherchent à préserver la sécurité d'approvisionnement au niveau national peuvent être très contre-intuitifs, étant données les interactions entre les pays voisins et leurs effets sur les investissements en génération et en interconnexion. Il est donc très important pour les régulateurs de comprendre ces interactions et de coordonner décisions à fin de pouvoir profiter de l'interconnexion sans mettre en danger la sécurité d'approvisionnement. Mais il faut être conscients que même quand l'intégration amène de bénéfices pour la région, certains participants au marché sont perdants et pourraient essayer de bloquer le processus d'intégration.

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ABSTRACT The objective of this study was to evaluate the thermoregulatory response of dairy buffaloes in pre-milking and post-milking. To identify animal thermoregulatory capacity, skin surface temperatures were taken by an infrared thermometer (SST), a thermographic camera (MTBP) as well as respiratory rate records (RR). Black Globe and Humidity Index (BGHI), radiating thermal load (RTL) and enthalpy (H) were used to characterize the thermal environment. Artificial Neural Networks analyzed those indices as well as animal physiological data, using a single layer trained with the least mean square (LMS) algorithm. The results indicated that pre-milking and post-milking environments reached BGHI, RR, SST and MTBP values above thermal neutrality zone for buffaloes. In addition, limits of surface skin temperatures were mostly influenced by changing ambient conditions to the detriment of respiratory rates. It follows that buffaloes are sensitive to environmental changes and their skin temperatures are the best indicators of thermal comfort in relation to respiratory rate.

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The capacity of beams is a very important factor in the study of durability of structures and structural members. The capacity of a high-strength steel I-beam made of S960 QC was investigated in this study. The investigation included assessment of the service limits and ultimate limits of the steel beam. The thesis was done according to European standards for steel structures, Eurocode 3. An analytical method was used to determine the throat thickness, deformation, elastic and plastic moment capacities as well as the fatigue life of the beam. The results of the analytical method were compared with those obtained by Finite Element Analysis (FEA). Elastic moment capacity obtained by the analytical method was 172 kNm. FEA and the analytical method predicted the maximum lateral-torsional buckling (LTB) capacity in the range of 90-93 kNm and the probability of failure as a result of LTB is estimated to be 50%. The lateral buckling capacity meant that the I-beam can carry a safe load of 300 kN instead of the initial load of 600 kN. The beam is liable to fail shortly after exceeding the elastic moment capacity. Based on results in of the different approaches, it was noted that FEA predicted higher deformation values on the load-deformation curve than the analytical results. However, both FEA and the analytical methods predicted identical results for nominal stress range and moment capacities. Fatigue life was estimated to be in the range of 53000-64000 cycles for bending stress range using crack propagation equation and strength-life approach. As Eurocode 3 is limited to steel grades up to S690, results for S960 must be verified with experimental data and appropriate design rules.

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In Metropolitan Area of Mexico City, most of urban displacements happen through semi formal public transportation: small and medium capacity vehicles operated by small private enterprises, through a concession scheme. This kind of public transportation has been playing a major role in the Mexican capital. On one hand, it has been one of the conditions for urbanization to be possible. On the other hand, despite its uncountable deficiencies, public transportation has allowed for a long time the whole population to be able to move within this huge metropolis. However, that important function with regards to integration has now reached its limits in the most recent suburbs of the city, where a new mode of urbanization is taking place, based on massive production of very big social housing gated settlements. Public transportation tends to constitute here a factor of exclusion and households meet with important difficulties for their daily mobility.