573 research outputs found

    Unit root and cointegration tests for cross-sectionally correlated panels. Estimating regional production functions

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    This paper employs recently developed non stationary panel methodologies that assume some cross-section dependence to estimate the production function for Italian regions in the industrial sector over the period 1970-1998. The analysis consists in three steps. First, unit root tests for cross-sectionally dependent panels are used. Second, the existence of a co-integrating relationship among value added, physical capital and human capital-augmented labor is investigated. The Dynamic OLS (DOLS) and Fully modified (FMOLS) estimators developed by Pedroni (1996, 2000, 2001) and the Panel Dynamic OLS (PDOLS) estimator proposed by Mark and Sul (2003)are then used to estimate the long run relationship between the variables considered.panel cointegration; cross-section dependence; production function

    Unit root and cointegration tests for cross-sectionally correlated panels - Estimating regional production functions

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    There is a plethora of studies of regional production functions using stationary panel data. Only some recent works consider non-stationary panel data. All of them assume the hypothesis of cross-section independence. Here, we claim that the independence assumption is too strong when regional data are used. In this paper, the cross-section independence assumption is released and cross-sectional dependence is assumed. First, unit roots and cointegration properties of the panel dataset are properly investigated by using newly developed tests for cross-sectionally dependent panels. Second, dynamic OLS (DOLS) and recent regression models for cross-sectionally correlated panels are used to estimate the cointegrated relationship between value added, physical and human capital, for Italian regions over the period 1970-1998.

    Search for the dark photon in π0π^0 decays

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    A sample of 1.69imes1071.69 imes 10^7 fully reconstructed pi0ogammae+e−pi^0 ogamma e^+e^- decay candidates collected by the NA48/2 experiment at CERN in 2003--2004 is analysed to search for the dark photon (Aâ€ČA') production in the pi0ogammaAâ€Čpi^0 ogamma A' decay followed by the prompt Aâ€Čoe+e−A' o e^+e^- decay. No signal is observed, and an exclusion region in the plane of the dark photon mass mAâ€Čm_A' and mixing parameter arepsilon2arepsilon^2 is established. The obtained upper limits on arepsilon2arepsilon^2 are more stringent than the previous limits in the mass range 9~ m MeV/c^2<70~ m MeV/c^2. The NA48/2 sensitivity to the dark photon production in the KpmopipmAâ€ČK^pm opi^pm A' decay is also evaluated

    Limited genetic connectivity between gorgonian morphotypes along a depth gradient

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    Gorgonian species show a high morphological variability in relation to the environment in which they live. In coastal areas, parameters such as temperature, light, currents, and food availability vary significantly with depth, potentially affecting morphology of the colonies and the structure of the populations, as well as their connectivity patterns. In tropical seas, the existence of con- nectivity between shallow and deep populations supported the hypothesis that the deep coral reefs could potentially act as (reproductive) refugia fostering re-colonization of shallow areas after mortality events. Moreover, this hypothesis is not so clear accepted in temperate seas. Eunicella singularis is one of the most common gorgonian species in Northwestern Mediterranean Sea, playing an important role as ecosystem engineer by providing biomass and com- plexity to the coralligenous habitats. It has a wide bathymetric distribution ranging from about 10 m to 100 m. Two depth-related morphotypes have been identified, differing in colony mor- phology, sclerite size and shape, and occurrence of symbiotic algae, but not in mitochondrial DNA haplotypes. In the present study the genetic structure of E. singularis populations along a horizontal and bathymetric gradient was assessed using microsatellites and ITS1 sequences. Restricted gene flow was found at 30-40 m depth between the two Eunicella morphotypes. Conversely, no genetic structuring has been found among shallow water populations within a spatial scale of ten kilometers. The break in gene flow between shallow and deep populations contributes to explain the morphological variability observed at different depths. Moreover, the limited vertical connectivity hinted that the refugia hypothesis does not apply to E. singularis. Re-colonization of shallow water populations, occasionally affected by mass mortality events, should then be mainly fueled by larvae from other shallow water populations

    Monitoring and mapping soil functionality in degraded areas of organic European vineyards

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    PĂłster presentado en el 11th International Terroir Congress, celebrado en Willamette Valley, Oregon (Estados Unidos) del 10 al 14 de julio de 2016.Soil malfunctioning, caused by an improper land preparation before vine plantation and/or management, is a common problem in European vineyards. Soil malfunctioning can include: reduced contribution of the soil fauna, poor organic matter content, imbalance nutritional status, altered pH, water deficiency, soil compaction and/or scarce oxygenation. To address these problems, ReSolVe, a transnational European research project, aimed at testing the effects of selected agronomic strategies for restoring optimal soil functionality in degraded areas within organic vineyard. The project involves 8 research groups in 6 different EU countries (Italy, Spain, France, Sweden, Slovenia, and Turkey) with experts from several disciplines including soil science, ecology, microbiology, grapevine physiology, viticulture, and biometry. The experimental vineyards are situated in Italy (Chianti hills and Maremma plain, Tuscany), Spain (La Rioja), France (Bordeaux and Languedoc), and Slovenia (Primorska) for winegrapes, and in Turkey (Adana and Mersin) for tablegrapes. Three different restoring strategies have been implemented: (i) compost, (ii) green manure with winter legumes, and (iii) dry mulching with cover crops. These strategies have being tested according to their efficiency to improve i) plant and root growth; and ii) grape yield and quality; optimize iii) the quality of soil ecosystem services; and iv) the terroir effect. The first activity of the project was characterizing and mapping the degraded areas within experimental vineyards. In the work we used non-invasive technologies to characterize soil and plant status. In Spanish and Italian vineyards, the delineation of degraded areas was performed by gamma-ray spectroscopy for topsoil, RGB machine vision for canopy status and thermography for plant water status. Gamma-ray spectroscopy measured continuously the natural gamma-ray emitted from the first 30-40 cm of soil, calculating the contribution of the main radionuclides (40K, 232Th, and 238U). The spectra of gamma-ray were able to provide information about mineralogy, texture, surficial stoniness and carbonates. RGB and thermal cameras were used to assess canopy porosity, leaf area exposure and vine water status of both degraded and non-degraded areas. All soil, canopy and water status parameters were mapped.Peer Reviewe

    Severe aortic stenosis with preserved ejection fraction and evidence of impairment in structure, myocardial strain and ventricular function: A new contribution to clinical decision making

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    Background: Left ventricular ejection fraction (LVEF) is among the parameters that are usually employed to define surgical timing of severe aortic stenosis (AS). Our hypothesis states that even when their LVEF is preserved, patients with severe symptomatic AS have impaired myocardial structure and function, and such impairment is related to the deleterious progression of left ventricular hypertrophy (LVH) from the compensated to the decompensated stage, as shown by the changes in diastolic function and the increase in left ventricular end-diastolic pressure (LVEDP). Methods and Results: A total of 26 patients with severe AS and LVEF &gt; 50% referred for aortic valve replacement underwent catheterization, echocardiography and an intraoperative biopsy. Patients with severe symptomatic AS were classified as: group 1 (G1; compensated LVH, LVEDP &lt; 15 mm Hg without coronary artery disease [CAD], n = 7), group 2a (G2a, decom­pensated LVH, without CAD, n = 7), and group 2b (G2b, decompensated LVH with CAD, n = 12). Differences were seen in the following: myocyte area [ÎŒm2]: G1: 328 ± 66, G2a: 376 ± 22, G2b: 385 ± 13, p &lt; 0.01; collagen volume [%]: G1: 4.77 ± 1.27, G2a: 8.40 ± 1.27, G2b: 11.05 ± 3.08, p &lt; 0.01; LVEDP normalized by diastolic diameter [mm Hg/mm]: G1: 0.27 ± 0.01, G2a: 0.39 ± 0.06, G2b: 0.44 ± 0.11, p &lt; 0.02; +dP/dtmax/LVEDP [mm Hg/s/mm Hg]: G1: 176 ± 45, G2a: 89.6 ± 20, G2b: 113.1 ± 41, p &lt; 0.01; two-dimensional peak systolic longitudinal strain [%]: G1: –17.7 ± 4.75, G2a: –13.4 ± 3.04, G2b: –13.5 ± 3.13, p &lt; 0.05. Conclusions: Patients with severe symptomatic AS and preserved ejection fraction who de­velop decompensated LVH characterized by increased LVEDP, exhibit an abnormal myocardial structure and diastolic and systolic impairment

    Presumptive myocarditis with ST-Elevation myocardial infarction presentation in young males as a new syndrome. Clinical significance and long term follow up

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    <p>Abstract</p> <p>Background</p> <p>Acute myocarditis may mimic myocardial infarction, since affected patients complain of "typical" chest pain, the ECG changes are identical to those observed in acute coronary syndromes, and serum markers are increased. We describe a case series of presumptive myocarditis with ST segment elevation on admission ECG.</p> <p>Methods and Results</p> <p>From 1998 to 2009, 21 patients (20 males; age 17-42 years) were admitted with chest pain, persistent ST segment elevation, serum enzyme and troponine release. All but one patients had fever and flu-like symptoms prior to admission. No abnormal Q wave appeared in any ECG tracing, and angiography did not show significant coronary artery disease. Patients remained asymptomatic at long term follow-up, except 2 who experienced a late relapse, with the same clinical, electrocardiographic and serum findings as in the first clinical presentation.</p> <p>Conclusion</p> <p>Presumptive myocarditis of possible viral origin characterized by ST elevation mimicking myocardial infarction, good short term prognosis and some risk for recurrence is relatively frequent in young males and appears as a distinct clinical condition.</p

    The ecology of exercise: mechanisms underlying Individual variation in behavior, activity, and performance: an introduction to symposium

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    Wild animals often engage in intense physical activity while performing tasks vital for their survival and reproduction associated with foraging, avoiding predators, fighting, providing parental care, and migrating. In this theme issue we consider how viewing these tasks as “exercise”—analogous to that performed by human athletes—may help provide insight into the mechanisms underlying individual variation in these types of behaviors and the importance of physical activity in an ecological context. In this article and throughout this issue, we focus on four key questions relevant to the study of behavioral ecology that may be addressed by studying wild animal behavior from the perspective of exercise physiology: (1) How hard do individual animals work in response to ecological (or evolutionary) demands?; (2) Do lab-based studies of activity provide good models for understanding activity in free-living animals and individual variation in traits?; (3) Can animals work too hard during “routine” activities?; and (4) Can paradigms of “exercise” and “training” be applied to free-living animals? Attempts to address these issues are currently being facilitated by rapid technological developments associated with physiological measurements and the remote tracking of wild animals, to provide mechanistic insights into the behavior of free-ranging animals at spatial and temporal scales that were previously impossible. We further suggest that viewing the behaviors of non-human animals in terms of the physical exercise performed will allow us to fully take advantage of these technological advances, draw from knowledge and conceptual frameworks already in use by human exercise physiologists, and identify key traits that constrain performance and generate variation in performance among individuals. It is our hope that, by highlighting mechanisms of behavior and performance, the articles in this issue will spur on further synergies between physiologists and ecologists, to take advantage of emerging cross-disciplinary perspectives and technologies

    Space charge in ionization detectors and the NA48 electromagnetic calorimeter

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    The subject of space charge due to positive ions slowly moving in parallel plate ionization chambers is considered. A model for the degradation of the detector response is developed, with particular emphasis on electromagnetic calorimeters. The topics discussed include: (a) the stationary and (b) the time dependent cases; (c) the limit of very large space charge; (d) the electric field dependence of the electron drift velocity; (e) the effect of longitudinal development of showers; (f) the behavior of the average reductions of response and (g) the non-uniformity of response for different positions of the shower axis inside the cell defined by the electrodes. The NA48 calorimeter is used as application and for comparison of results
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