53 research outputs found

    Covering point sets with two disjoint disks or squares

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    Open archive-ElsevierWe study the following problem: Given a set of red points and a set of blue points on the plane, find two unit disks CR and CB with disjoint interiors such that the number of red points covered by CR plus the number of blue points covered by CB is maximized. We give an algorithm to solve this problem in O(n8/3 log2 n) time, where n denotes the total number of points. We also show that the analogous problem of finding two axis-aligned unit squares SR and SB instead of unit disks can be solved in O(nlog n) time, which is optimal. If we do not restrict ourselves to axis-aligned squares, but require that both squares have a common orientation, we give a solution using O(n3 log n) time

    Space Charge Studies on Mid-voltage Cable by Thermally Stimulated Depolarization Currents in the Melting Temperature Range.

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    In the present work, a XLPE mid-voltage cable from General Cable CO. has been studied by Thermally stimulated depolarization currents. Systematic measurements have been carried out in order to compare the conductive processes in this cable with previous results. Depolarization current as a function of thermal annealing, thermal history, polarizing field and polarizing time and temperature has been obtained. The results show the presence of a broad and complex heteropolar process between 60 and 120°C as expected. Annealing of the sample at temperatures above SOT develops an homopolar contribution associated to chemical components diffused from the cable semiconducting layers into the XLPE bulk. For annealing times of 60min at 140T and 2 days at 90°C, the homoplar current intensity reaches a maximum, decreasing and recovering the heteropolar sign with further annealing. Experiments performed with different polarizing times and temperatures show as well the presence of an homopolar contribution, overlapped to the heteropolar behavior, that increases continuously with polarizing time. These results indicate that conductive processes within the XLPE are probably responsible of homopolar charge injection

    Comparative Study of Conductivity in Mid-Voltage Cable XLPE Insulation

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    It is well established that space charge conditions insulation lifetime. Because of this, space charge formation and relaxation processes characterization has become a very active research field, not only from an basic science point of view, but also in order to improve insulation performance in cable and other devices. In the case of mid-voltage power cable, crosslinked polyethylene is widely used as insulator. Service temperature of such cables is around 90°C, which in the case of the cable insulation studied is in the melting temperature range. In previous works it has been determined that at this temperature conductivity plays a relevant role in the space charge relaxation process, so that the characterization of conductive processes at service temperature may become important in order to enhance cable insulation performance. The aim of this work is to contribute to a better knowledge of the conductive properties of XLPE in both time and frequency domains

    Effect of annealing on conductivity in XLPE mid-voltage cable insulation

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    A new study of the electrical conductivity of crosslinked polyethylene (XLPE) mid-voltage (MV) cable insulation is presented. Its main objective is to show the effect of annealing treatments on MV cables under actual service conditions. Complementary time domain (absorption/resorption currents) and frequency domain (dynamic electrical analysis) techniques are applied on different laboratory samples containing XLPE insulations: sections of XLPE insulated cable (with and without semiconducting screens) in the case of absorption/resorption currents and, in the case of dynamic electrical analysis, a thin ribbon obtained from the cable insulation by mechanical procedures. For annealing temperatures below a certain critical temperature, conductivity decreases both for XLPE cylinders (cable sections from which inner and outer semiconducting screens have been removed) and for real cables (sections of cable with semiconducting screens) but its value is smaller in the case of cables. If the annealing temperature is higher than the critical temperature, the behaviour of conductivity is more complex. In XLPE, cylinders conductivity initially decreases with the annealing time but after some annealing time it begins to increase, it passes over a maximum and eventually it decreases monotonically. In the case of real cable sections, conductivity grows, tending to a saturation value, which is noticeably higher than the corresponding value of the maximum obtained for XLPE cylinders. The experimental results are explained satisfactorily by means of the Mott equation that takes into account hopping conduction assisted both by temperature and electric field

    La imagen de la energía nuclear en la prensa española de proximidad: ¿Son los medios de comunicación un stakeholder relevante para el sector atómico?

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    Los medios de comunicación han sido tradicionalmente protagonistas en la formación de la opinión pública acerca de temas nucleares. La prensa tiene prestigio en el debate público y capacidad de influir sobre la población a través del tratamiento de la energía nuclear en cualquier género periodístico. ¿Sobre qué temas nucleares informan los medios de proximidad? ¿Qué imagen trasladan a la opinión pública los periódicos provinciales que cubren la actividad nuclear? ¿Qué acciones deben perseguir los gabinetes de comunicación de las centrales nucleares con los medios para informar sobre las acciones de la industria atómica? Para responder a ello, hemos realizado un análisis de contenido de los periódicos de proximidad de mayor difusión de las poblaciones cercanas a las plantas atómicas en España (2013-2017) y hemos entrevistado a los responsables de comunicación de las centrales nucleares españolas. Como conclusiones principales de este estudio podemos decir que los periódicos de mayor difusión en las provincias con central nuclear transmiten una imagen negativa del sector nuclear hacia sus lectores y, por lo tanto, las centrales atómicas, si pretenden revertir la situación, deben relacionarse con los periodistas para poder trasladar a la sociedad la utilidad de su apuesta energética.Els mitjans de comunicació han estat tradicionalment protagonistes en la formació de l’opinió pública sobre temes nuclears. La premsa té prestigi en el debat públic i capacitat d’influir sobre la població a través del tractament de l’energia nuclear en qualsevol gènere periodístic. Sobre quins temes nuclears informen els mitjans de proximitat? Quina imatge traslladen a l’opinió pública els diaris provincials que cobreixen l’activitat nuclear? Quines accions han de perseguir els gabinets de comunicació de les centrals nuclears amb els mitjans per informar sobre les accions de la indústria atòmica? Per respondre aquestes preguntes, hem fet una anàlisi de contingut dels diaris de proximitat de major difusió de les poblacions properes a les plantes atòmiques a Espanya (2013- 2017) i hem entrevistat els responsables de comunicació de les centrals nuclears espanyoles. Com a conclusions principals d’aquest estudi podem dir que els diaris de major difusió a les províncies amb central nuclear transmeten una imatge negativa del sector nuclear cap als seus lectors i, per tant, les centrals atòmiques, si pretenen revertir la situació, han de relacionar-se amb els periodistes per poder traslladar a la societat la utilitat de la seva aposta energètica.The media have traditionally had a prominent role in the formation of public opinion on nuclear issues. The press has a good reputation in the public sphere and the ability to influence citizens through the treatment of nuclear energy in any journalistic genre. But, what nuclear energy topics do the local media report? What image do the local media transmit to the public? What strategies should communication departments of nuclear power plants implement to inform about their work? To answer these questions, we performed a content analysis (2013-2017) of the most important local newspapers that cover the activity of nuclear power plants in Spain and interviewed the heads of communication of Spanish nuclear power plants. We conclude that the most important local newspapers transmit a negative image of the nuclear sector to their readers and that nuclear power plants must interact with journalists to inform society about the usefulness of nuclear energy

    Auscultation of velcro crackles is associated with usual interstitial pneumonia

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    Auscultation of Velcro crackles has been proposed as a key finding in physical lung examination in patients with interstitial lung diseases (ILDs), especially in idiopathic pulmonary fibrosis (IPF). However, no studies have been carried out to assess the association of Velcro crackles with other clinical variables. We evaluated a cohort of 132 patients, prospectively and consecutively included in our ILD diagnostic program at a tertiary referral center. All patients were auscultated during the physical examination. The patients were divided into 2 groups: "presence" or "nonpresence" of bilateral Velcro crackles. Of all patients assessed, 83 (63%) presented Velcro crackles in the respiratory auscultation. Patients with Velcro crackles usually had more frequently cough and dyspnea at the moment of diagnosis. Forced vital capacity (P = 0.002) and lung diffusion capacity for carbon monoxide (P = 0.04) was lower in these patients. The ILD-GAP index was higher in the group with Velcro crackles (P = 0.01). All patients with usual interstitial pneumonia (UIP) in high-resolution computed tomography and all patients with final IPF diagnosis presented Velcro crackles. In multivariate analysis, the presence of Velcro crackles was independently associated with an UIP pattern. In patients suspected of having ILD, the auscultation of Velcro crackles was associated with UIP, a possibility which must be taken into consideration in early ILD detection in primary care

    Impact of a systematic evaluation of connective tissue disease on diagnosis approach in patients with interstitial lung diseases

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    To date, there is no clear agreement regarding which is the best method to detect a connective tissue disease (CTD) during the initial diagnosis of interstitial lung diseases (ILD). The aim of our study was to explore the impact of a systematic diagnostic strategy to detect CTD-associated ILD (CTD-ILD) in clinical practice, and to clarify the significance of interstitial pneumonia with autoimmune features (IPAF) diagnosis in ILD patients. Consecutive patients evaluated in an ILD Diagnostic Program were divided in 3 groups: IPAF, CTD-ILD, and other ILD forms. Clinical characteristics, exhaustive serologic testing, high resolution computed tomography (HRCT) images, lung biopsy specimens, and follow-up were prospectively collected and analyzed. Among 139 patients with ILD, CTD was present in 21 (15.1%), 24 (17.3%) fulfilled IPAF criteria, and 94 (67.6%) were classified as other ILD forms. Specific systemic autoimmune symptoms such as Raynaud phenomenon (19%), inflammatory arthropathy (66.7%), and skin manifestations (38.1%) were more frequent in CTD-ILD patients than in the other groups (all P< .001). Among autoantibodies, antinuclear antibody was the most frequently found in IPAF (42%), and CTD-ILD (40%) (P= .04). Nonspecific interstitial pneumonia, detected by HRCT scan, was the most frequently seen pattern in patients with IPAF (63.5%), or CTD-ILD (57.1%) (P< .001). In multivariate analysis, a suggestive radiological pattern by HRCT scan (odds ratio [OR] 15.1, 95% confidence interval [CI] 4.7-48.3, P< .001) was the strongest independent predictor of CTD-ILD or IPAF, followed by the presence of clinical features (OR 14.6, 95% CI 4.3-49.5, P< .001), and serological features (OR 12.4, 95% CI 3.5-44.0, P< .001). This systematic diagnostic strategy was useful in discriminating an underlying CTD in patients with ILD. The defined criteria for IPAF are fulfilled by a considerable proportion of patients referred for ILD

    Acute exacerbations of idiopathic pulmonary fibrosis: Does clinical stratification or steroid treatment matter?

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    Acute exacerbation (AE) of idiopathic pulmonary fibrosis (IPF) is defined as a sudden acceleration of the disease with the appearance of pulmonary infiltrates superimposed on the characteristic pattern of IPF that leads to a significant decline in lung function. It has high in-hospital mortality rates, despite medical treatment with systematic steroids. We sought to investigate whether there were in-hospital mortality differences according to clinical stratification (AE, suspected AE, or AE of known cause) and/or treatment with systemic steroids. We reviewed the clinical characteristics and outcomes of patients with IPF admitted to our hospital during the years 2003-2014 due to a worsening of their clinical status. We identified 50 IPF patients, 9 with AE (18%), 12 with suspected exacerbation (24%), and 29 with AE of known cause (58%), mostly respiratory infections. In-hospital mortality was similar in the three groups (33% vs. 17% vs. 34%, respectively). Likewise, we did not find differences between them with respect to the use of systemic steroids (length of treatment duration or total dose). Nevertheless, there was an independent association between in-hospital mortality and high average daily steroid dose. We did not observe significant differences in prognosis or use of systemic steroids according to current diagnostic stratification groups in patients hospitalized because of an exacerbation of IPF

    Infarction in the territory of the anterior cerebral artery: clinical study of 51 patients

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    <p>Abstract</p> <p>Background</p> <p>Little is known about clinical features and prognosis of patients with ischaemic stroke caused by infarction in the territory of the anterior cerebral artery (ACA). This single centre, retrospective study was conducted with the following objectives: a) to describe the clinical characteristics and short-term outcome of stroke patients with ACA infarction as compared with that of patients with ischaemic stroke due to middle cerebral artery (MCA) and posterior cerebral artery (PCA) infarctions, and b) to identify predictors of ACA stroke.</p> <p>Methods</p> <p>Fifty-one patients with ACA stroke were included in the "Sagrat Cor Hospital of Barcelona Stroke Registry" during a period of 19 years (1986–2004). Data from stroke patients are entered in the stroke registry following a standardized protocol with 161 items regarding demographics, risk factors, clinical features, laboratory and neuroimaging data, complications and outcome. The characteristics of these 51 patients with ACA stroke were compared with those of the 1355 patients with MCA infarctions and 232 patients with PCA infarctions included in the registry.</p> <p>Results</p> <p>Infarctions of the ACA accounted for 1.3% of all cases of stroke (<it>n </it>= 3808) and 1.8% of cerebral infarctions (<it>n </it>= 2704). Stroke subtypes included cardioembolic infarction in 45.1% of patients, atherothrombotic infarction in 29.4%, lacunar infarct in 11.8%, infarct of unknown cause in 11.8% and infarction of unusual aetiology in 2%. In-hospital mortality was 7.8% (<it>n </it>= 4). Only 5 (9.8%) patients were symptom-free at hospital discharge. Speech disturbances (odds ratio [OR] = 0.48) and altered consciousness (OR = 0.31) were independent variables of ACA stroke in comparison with MCA infarction, whereas limb weakness (OR = 9.11), cardioembolism as stroke mechanism (OR = 2.49) and sensory deficit (OR = 0.35) were independent variables associated with ACA stroke in comparison with PCA infarction.</p> <p>Conclusion</p> <p>Cardioembolism is the main cause of brain infarction in the territory of the ACA. Several clinical features are more frequent in stroke patients with ACA infarction than in patients with ischaemic stroke due to infarction in the MCA and PCA territories.</p

    Demographic and clinical profile of idiopathic pulmonary fibrosis patients in Spain: the SEPAR National Registry

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    BackgroundLittle is known on the characteristics of patients diagnosed with idiopathic pulmonary fibrosis (IPF) in Spain. We aimed to characterize the demographic and clinical profile of IPF patients included in the IPF National Registry of the Spanish Respiratory Society (SEPAR).MethodsThis is a prospective, observational, multicentre and nationwide study that involved 608 IPF patients included in the SEPAR IPF Registry up to June 27th, 2017, and who received any treatment for their disease. IPF patients were predominantly males, ex-smokers, and aged in their 70s, similar to other registries.ResultsUpon inclusion, meanSD predicted forced vital capacity was 77.6%+/- 19.4, diffusing capacity for carbon monoxide was 48.5%+/- 17.7, and the 6-min walk distance was 423.5m +/- 110.4. The diagnosis was mainly established on results from the high-resolution computed tomography in the proper clinical context (55.0% of patients), while 21.2% of patients required invasive procedures (surgical lung biopsy) for definitive diagnosis. Anti-fibrotic treatment was prescribed in 69.4% of cases, 51.5% pirfenidone and 17.9% nintedanib, overall with a good safety profile.Conclusions The SEPAR IPF Registry should help to further characterize current characteristics and future trends of IPF patients in Spain and compare/pool them with other registries and cohorts
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