2,738 research outputs found

    Evaluation of PV technology implementation in the building sector

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    This paper presents a simulation case that shows the impact on energy consumption of a building applying photovoltaic shading systems. In order to make photovoltaic application more economical, the effect of a photovoltaic facade as a passive cooling system can result in a considerable energy cost reduction, with positive influence on the payback time of the photovoltaic installation. Photovoltaic shading systems can be applied to both refurbishment of old buildings and to new-build, offering attractive and environmentally integrated architectural solutions

    Possible Subclinical Leaflet Thrombosis in Bioprosthetic Aortic Valves

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    To the Editor: Makkar et al. (Nov. 19 issue)(1) report possible subclinical leaflet thrombosis in up to 40% of patients involved in a clinical trial of transcatheter aortic-valve replacement (TAVR). In contrast, we found a relatively low incidence (7%) of possible subclinical valve leaflet thrombosis among patients in our series in which 255 patients underwent TAVR with the use of a CoreValve prosthesis. A retrospective review of our series (unpublished data) showed that in 104 patients, cardiac computed tomography (CT) at a median of 7 days after implantation (range, 3 to 87) (in 51 patients), transesophageal echocardiography at a median . . 

    Weak formulation for singular diffusion equation with dynamic boundary condition

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    In this paper, we propose a weak formulation of the singular diffusion equation subject to the dynamic boundary condition. The weak formulation is based on a reformulation method by an evolution equation including the subdifferential of a governing convex energy. Under suitable assumptions, the principal results of this study are stated in forms of Main Theorems A and B, which are respectively to verify: the adequacy of the weak formulation; the common property between the weak solutions and those in regular problems of standard PDEs.Comment: 23 page

    Coming to America: Multiple Origins of New World Geckos

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    Geckos in the Western Hemisphere provide an excellent model to study faunal assembly at a continental scale. We generated a time-calibrated phylogeny, including exemplars of all New World gecko genera, to produce a biogeographic scenario for the New World geckos. Patterns of New World gecko origins are consistent with almost every biogeographic scenario utilized by a terrestrial vertebrate with different New World lineages showing evidence of vicariance, dispersal via temporary land bridge, overseas dispersal, or anthropogenic introductions. We also recovered a strong relationship between clade age and species diversity, with older New World lineages having more species than more recently arrived lineages. Our data provide the first phylogenetic hypothesis for all New World geckos and highlight the intricate origins and ongoing organization of continental faunas. The phylogenetic and biogeographical hypotheses presented here provide an historical framework to further pursue research on the diversification and assembly of the New World herpetofauna

    Intrarenal Resistance Index as a Prognostic Parameter in Patients with Liver Cirrhosis Compared with Other Hepatic Scoring Systems

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    Background and Aims: Patients with advanced liver cirrhosis who develop renal dysfunction have a poor prognosis. Elevated intrarenal resistance indices (RIs) due to renal vascular constriction have been described before in cirrhotic patients. In the current study, we prospectively investigated the course of intrarenal RIs and compared their prognostic impact with those of the Model for End-Stage Liver Disease (MELD) and the Child-Pugh scores. Methods: Sixty-three patients with liver cirrhosis underwent a baseline visit which included a sonographic examination and laboratory tests. Forty-four patients were prospectively monitored. The end points were death or survival at the day of the follow-up visit. Results: In 28 patients, a follow-up visit was performed after 22 8 months (group 1). Sixteen patients died during follow-up after 12 8 months (group 2). Group 2 patients showed a significantly higher baseline RI (0.76 +/- 0.05) than group 1 patients (RI = 0.72 +/- 0.06; p < 0.05). As shown by receiver operating characteristic analysis, the RI and the MELD score achieved similar sensitivity and specificity {[}area under the curve (AUC): 0.722; 95% confidence interval (95% CI): 0.575-0.873 vs. AUC: 0.724; 95% CI: 0.575-0.873, z = 0.029, n.s.] in predicting survival and were superior to the Child-Pugh score (AUC: 0.677; 96% Cl: 0.518-0.837). Conclusion: The RI is not inferior in sensitivity and specificity to the MELD score. Cirrhotic patients with elevated RIs have impaired short- and long-term survival. The RI may help identify high-risk patients that require special therapeutic care. Copyright (C) 2012 S. Karger AG, Base

    A philosophical context for methods to estimate origin-destination trip matrices using link counts.

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    This paper creates a philosophical structure for classifying methods which estimate origin-destination matrices using link counts. It is claimed that the motivation for doing so is to help real-life transport planners use matrix estimation methods effectively, especially in terms of trading-off observational data with prior subjective input (typically referred to as 'professional judgement'). The paper lists a number of applications that require such methods, differentiating between relatively simple and highly complex applications. It is argued that a sound philosophical perspective is particularly important for estimating trip matrices in the latter type of application. As a result of this argument, a classification structure is built up through using concepts of realism, subjectivity, empiricism and rationalism. Emphasis is put on the fact that, in typical transport planning applications, none of these concepts is useful in its extreme form. The structure is then used to make a review of methods for estimating trip matrices using link counts, covering material published over the past 30 years. The paper concludes by making recommendations, both philosophical and methodological, concerning both practical applications and further research

    On a diffuse interface model for tumour growth with non-local interactions and degenerate mobilities

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    We study a non-local variant of a diffuse interface model proposed by Hawkins--Darrud et al. (2012) for tumour growth in the presence of a chemical species acting as nutrient. The system consists of a Cahn--Hilliard equation coupled to a reaction-diffusion equation. For non-degenerate mobilities and smooth potentials, we derive well-posedness results, which are the non-local analogue of those obtained in Frigeri et al. (European J. Appl. Math. 2015). Furthermore, we establish existence of weak solutions for the case of degenerate mobilities and singular potentials, which serves to confine the order parameter to its physically relevant interval. Due to the non-local nature of the equations, under additional assumptions continuous dependence on initial data can also be shown.Comment: 28 page

    Towards a liquid Argon TPC without evacuation: filling of a 6 m^3 vessel with argon gas from air to ppm impurities concentration through flushing

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    In this paper we present a successful experimental test of filling a volume of 6 m3^3 with argon gas, starting from normal ambient air and reducing the impurities content down to few parts per million (ppm) oxygen equivalent. This level of contamination was directly monitored measuring the slow component of the scintillation light of the Ar gas, which is sensitive to {\it all} sources of impurities affecting directly the argon scintillation.Comment: 9 pages, 6 figures, to appear in Proc. 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba, March 201

    Enfermedad renal crónica : una epidemia

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    Fil: Alabart, E.. Universidad Nacional de TucumánFil: González, Roxana. Universidad Nacional de TucumánFil: Alós, B.. Universidad Nacional de TucumánFil: Romero, A.. Universidad Nacional de TucumánFil: Barada, C.. Universidad Nacional de TucumánFil: Zanetta, D.. Universidad Nacional de TucumánFil: Colli, G.. Universidad Nacional de Tucumá
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