4,530 research outputs found

    A visualization of the damage in Lead Tungstate calorimeter crystals after exposure to high-energy hadrons

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    The anticipated performance of calorimeter crystals in the environment expected after the planned High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN has to be well understood, before informed decisions can be made on the need for detector upgrades. Throughout the years of running at the HL-LHC, the detectors will be exposed to considerable fluences of fast hadrons, that have been shown to cause cumulative transparency losses in Lead Tungstate scintillating crystals. In this study, we present direct evidence of the main underlying damage mechanism. Results are shown from a test that yields a direct insight into the nature of the hadron-specific damage in Lead Tungstate calorimeter crystals exposed to 24 GeV/c protons.Comment: 8 pages, 6 figure

    The use of the Gompertz model in its differential form for weed emergence modelling

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    Los modelos empíricos que se utilizan para describir y predecir las emergencias de las malas hierbas basados en temperatura y humedad del suelo presentan dos puntos débiles: la ambigüedad que supone tomar como instante inicial de acumulación de grados termales o hidrotermales el día del laboreo y la necesidad de su validación posterior. La utilización de estos modelos en su forma diferencial haría innecesario establecer un día concreto de inicio de la acumulación de grados y podría aportar predicciones sin necesidad de validaciones. Para comprobar estas hipótesis, la ecuación de Gompertz, uno de los modelos más utilizados para describir emergencias, se ha aplicado en su forma diferencial a 35 conjuntos de datos de malas hierbas de diferentes localidades. El ajuste obtenido reproduce de forma satisfactoria la dinámica de emergencias observada en el campo y permite determinar con precisión el momento de aplicación de una medida de control.The Gompertz model, in its differential form, is used for weed emergence modelling. Empirical models that are used to describe the emergence patterns of weeds based on temperature and soil moisture have two weaknesses: the uncertainty of when to start counting and the need for validation. The use of these models in their differential form avoids setting up an ambiguous starting date and also avoids model validation. In order to check these hypotheses, the Gompertz equation, one of the models used most frequently for weed emergence, was verified in 35 data sets of weed species emergence from different areas within the Iberian Peninsula. In all cases, the emergence pattern and forecast for ideal weed control timing was sufficiently accurate

    The invasive species Sceliphron curvatum (F. Smith 1870) found in the Iberian Peninsula (Hymenoptera: Apoidea: Sphecidae)

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    [ES] Se menciona por primera vez Sceliphron curvatum (F.Smith 1870) de la Península Ibérica a partir del estudio de ejemplares provenientes del centro de España. Las presentes citas constituyen las más occidentales y meridionales conocidas de esta especie invasora en el continente europeo. Se comenta la actual distribución de esta avispa en Europa.[EN] Sceliphron curvatum is recorded from the Iberian Peninsula for the first time. Its known distribution in Europe is thus expanded; these records, from central Spain, are the most south-western currently known from the continent.Peer reviewe

    Rate of atrial fibrillation by Holter-Stroke Risk Analysis in undetermined TIA/rapidly improving stroke symptoms patients

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    Holter-SRA; Atrial fibrillation; NeurovascularHolter; Fibrilación auricular; NeurovascularHolter; Fibril·lació auricular; NeurovascularIntroduction: Holter-SRA (Stroke Risk Analysis) is an automated analysis of ECG monitoring for Atrial Fibrillation (AF) detection. The aim of this study was to evaluate the rate of AF in undetermined TIA/Rapidly improving stroke symptoms (RISS) patients. Methods: Prospective study of undetermined TIA/RISS patients who presented to the emergency department. Early vascular studies (angio CT, transthoracic echocardiography and ECG) were performed in emergency department. The Holter-SRA device was placed for 2 h and the patients were classified into: confirmed AF, high risk of AF or low risk of AF. Prolonged ambulatory monitoring (7 days) was carried out every month for patients with a high-risk pattern. The results were evaluated until definitive detection of AF or low-risk pattern. The endpoints were rate of AF and vascular recurrence at 90 days. Results: Over a period of 24 months, 83 undetermined TIA/RISS patients were enrolled. The mean age was 70 ± 10 years and 61% were men. The median ABCD2 score was 4 points (1-7). After 2 h of monitoring in the emergency department, AF was detected in one patient (1.2%), 51 patients with a low-risk pattern and 31 patients (37.3%) showed a high-risk pattern of AF. During the ambulatory monitoring, of the 31 patients high risk pattern patients, AF was diagnosed to 17 cases and of the 51 patients with a low-risk pattern, one case experienced a recurrent vascular due to undetected AF (1.9% false negative). Three patients (3.6%) suffered a vascular recurrence within the first 90 days, before AF diagnosis. Conclusions: In our study, AF was detected in 22.9% of the 83 patients with indeterminate TIA/RISS. Holter-SRA has allowed us to increase the detection of AF, especially those patients with a high-risk pattern in the first 3 months

    Деякі питання структурної теорії додавання множин

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    (uk) Доведено теорему про існування множин, а також знайдені значення у вершинах критичних трикутників.(en) Generalization of theorem on the existence. The meanings at the axis of critical triangles have been found

    Connecting p-gonal loci in the compactification of moduli space

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    Consider the moduli space M g of Riemann surfaces of genusg≥2 and its Deligne-Munford compactification M g ¯ . We are interested in the branch locus B g for g>2 , i.e., the subset of M g consisting of surfaces with automorphisms. It is well-known that the set of hyperelliptic surfaces (the hyperelliptic locus) is connected in M g but the set of (cyclic) trigonal surfaces is not. By contrast, we show that for g≥5 the set of (cyclic) trigonal surfaces is connected in M g ¯ . To do so we exhibit an explicit nodal surface that lies in the completion of every equisymmetric set of 3-gonal Riemann surfaces. For p>3 the connectivity of the p -gonal loci becomes more involved. We show that for p≥11 prime and genus g=p−1 there are one-dimensional strata of cyclic p -gonal surfaces that are completely isolated in the completion B g ¯ of the branch locus in M g ¯

    The response of taxonomic and functional diversity of the seed bank to agricultural intensification and soil properties in two Mediterranean cereal areas

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    Weed seed bank diversity has been severely impacted by agriculture intensifi cation. However, the functional consequences have been poorly studied in highly intensifi ed agro-ecosystems.Postprint (published version

    Spain: From massive immigration to vast emigration?

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    Large immigration flows during the 1995-2007 period increased the weight of foreigners living in Spain to 12 % of the total population. The rapid increase in unemployment associated with the Great Recession and the subsequent European debt crisis, substantially changed migration flows, so that, from the beginning of the 2010s, Spain experienced positive net outflows. In this paper, we take on three tasks. First, we show that sensitivity of migration flows to unemployment is similar between Spaniards born in Spain and foreigners that entered in Spain during the last 20 years. Second, we estimate the importance of past network effects of foreigners and the recent network effects of Spaniards in shaping these migration flows. Finally, we will use these estimations to conjecture that the rapid creation of networks of Spaniards abroad might keep their emigration rates growing, thus counterbalancing the effects of outflows due to the recent fall in the unemployment rate
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