2,875 research outputs found

    Trânsito de máquinas e resistência do solo à penetração em pomar de goiabeiras.

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    The study was conducted in irrigated commercial orchards of ?Paluma? and ?Pedro Sato? guavas, which were mapped with a Garmin GPS unit (Cx60). Sixty five sampling points were marked on a 21 x 21 m sampling grid. Gravimetric humidity and soil penetration resistance (SPR) were evaluated with the help of an automated penetrometer rod with a type 3 cone at a 45º angle (maximum SPR 15,100 kPa). Data with non-normal distribution were analyzed by geostatistics and interpolation by ordinary kriging. SPR values were higher where machine traffic occurs than on the lines where the crop is planted. There was spatial variability of the SPR among the layers evaluated, with the layer between 0.10-0.20 m, on the line of the machine traffic, presenting a higher SPR (>4000 kPa)

    Two-photon final states in peripheral heavy ion collisions

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    We discuss processes leading to two photon final states in peripheral heavy ion collisions at RHIC. Due to the large photon luminosity we show that the continuum subprocess γγγγ\gamma \gamma \to \gamma \gamma can be observed with a large number of events. We study this reaction when it is intermediated by a resonance made of quarks or gluons and discuss its interplay with the continuum process, verifying that in several cases the resonant process ovewhelms the continuum one. It is also investigated the possibility of observing a scalar resonance (the σ\sigma meson) in this process. Assuming for the σ\sigma the mass and total decay width values recently reported by the E791 Collaboration we show that RHIC may detect this particle in its two photon decay mode if its partial photonic decay width is of the order of the ones discussed in the literature.Comment: 10 pages, 8 figure

    Modelagem fuzzy para previsão da produtividade de goiabeira 'Paluma' em sistema agroindustrial em função da época de poda e do estado nutricional.

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    Abstract. As incertezas inerentes ao processo de produção de goiaba Paluma, principalmente quando se considera a época de poda e a avaliação do estado nutricional das plantas, podem interferir nos ganhos do fruticultor, pois a adubação representa boa parte dos custos de produção. Neste trabalho, apresentamos um modelo fuzzy para estimar a produtividade da goiabeira Paluma incorporando ao modelo as incertezas nos teores foliares de NPK e a época da poda. Consideraram-se nas relações fuzzy as tabelas de suficiência dos nutrientes e a experiência dos pesquisadores e produtores. O controlador fuzzy foi bem sucedido na tarefa de predizer a produtividade da goiabeira. Os resultados estimados quando comparados com os observados no campo apresentaram erro inferior a 10% para a maioria das amostras analisadas

    PERIODONTITIS AND EARLY MORTALITY IN ADULTS WITH KIDNEY FAILURE TREATED WITH HEMODIALYSIS: A MULTINATIONAL OBSERVATIONAL STUDY

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    Introduction and Aims: Periodontitis is associated with cardiovascular mortality in the general population and adults with chronic diseases, however prognostic data for periodontitis in the setting of kidney failure are sparse. The aim of the study was to evaluate whether periodontitis was prognostic for all-cause and cardiovascular-related death in adults with kidney failure. Methods: ORALD is a multinational cohort study in adults with kidney failure treated with haemodialysis in Europe (France, Hungary, Italy, Poland, Portugal and Spain) and Argentina. Periodontitis was measured at baseline according to the World Health Organization Community Periodontal Index. The outcomes were all-cause and cardiovascular mortality. Analyses were conducted using a fixed-effect Cox proportional hazards analysis and additionally using a random effects model fitted using shared frailty to account for clustering within countries. Results: Periodontitis was evaluable in 3338 dentate participants of which 1355 (40.6%) had moderate to severe periodontitis. During 6150 person-years of follow-up, 650 deaths occurred of which 325 were cardiovascular. In multivariable analyses, moderate to severe periodontitis was associated with a lower hazard of all-cause (HR 0.76, 95% confidence interval 0.64 to 0.90) and cardiovascular (0.69, 0.54 to 0.87) mortality. There was evidence of decreasing mortality risks with more severe periodontal disease (P≤0.001 for trend). However, when analyses accounted for clustering of participants within countries, the associations between periodontitis and all-cause (0.92, 0.75 to 1.11) and cardiovascular (0.83, 0.63 to 1.09) mortality were not significant. Similar results were observed in analyses restricted to participants with 12 or more teeth and when competing risks for cardiovascular death were considered. Conclusions: Unlike in the general population, there is limited evidence that periodontitis is independently associated with increased all-cause or cardiovascular mortality in adults with kidney failure

    Dynamical Patterns of Cattle Trade Movements

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    Despite their importance for the spread of zoonotic diseases, our understanding of the dynamical aspects characterizing the movements of farmed animal populations remains limited as these systems are traditionally studied as static objects and through simplified approximations. By leveraging on the network science approach, here we are able for the first time to fully analyze the longitudinal dataset of Italian cattle movements that reports the mobility of individual animals among farms on a daily basis. The complexity and inter-relations between topology, function and dynamical nature of the system are characterized at different spatial and time resolutions, in order to uncover patterns and vulnerabilities fundamental for the definition of targeted prevention and control measures for zoonotic diseases. Results show how the stationarity of statistical distributions coexists with a strong and non-trivial evolutionary dynamics at the node and link levels, on all timescales. Traditional static views of the displacement network hide important patterns of structural changes affecting nodes' centrality and farms' spreading potential, thus limiting the efficiency of interventions based on partial longitudinal information. By fully taking into account the longitudinal dimension, we propose a novel definition of dynamical motifs that is able to uncover the presence of a temporal arrow describing the evolution of the system and the causality patterns of its displacements, shedding light on mechanisms that may play a crucial role in the definition of preventive actions

    Dynamical Patterns of Cattle Trade Movements

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    Despite their importance for the spread of zoonotic diseases, our understanding of the dynamical aspects characterizing the movements of farmed animal populations remains limited as these systems are traditionally studied as static objects and through simplified approximations. By leveraging on the network science approach, here we are able for the first time to fully analyze the longitudinal dataset of Italian cattle movements that reports the mobility of individual animals among farms on a daily basis. The complexity and inter-relations between topology, function and dynamical nature of the system are characterized at different spatial and time resolutions, in order to uncover patterns and vulnerabilities fundamental for the definition of targeted prevention and control measures for zoonotic diseases. Results show how the stationarity of statistical distributions coexists with a strong and non-trivial evolutionary dynamics at the node and link levels, on all timescales. Traditional static views of the displacement network hide important patterns of structural changes affecting nodes' centrality and farms' spreading potential, thus limiting the efficiency of interventions based on partial longitudinal information. By fully taking into account the longitudinal dimension, we propose a novel definition of dynamical motifs that is able to uncover the presence of a temporal arrow describing the evolution of the system and the causality patterns of its displacements, shedding light on mechanisms that may play a crucial role in the definition of preventive actions

    Extending the temporal context of ethnobotanical databases: the case study of the Campania region (southern Italy)

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    <p>Abstract</p> <p>Background</p> <p>Ethnobotanical studies generally describe the traditional knowledge of a territory according to a "hic et nunc" principle. The need of approaching this field also embedding historical data has been frequently acknowledged. With their long history of civilization some regions of the Mediterranean basin seem to be particularly suited for an historical approach to be adopted. Campania, a region of southern Italy, has been selected for a database implementation containing present and past information on plant uses.</p> <p>Methods</p> <p>A relational database has been built on the basis of information gathered from different historical sources, including diaries, travel accounts, and treatises on medicinal plants, written by explorers, botanists, physicians, who travelled in Campania during the last three centuries. Moreover, ethnobotanical uses described in historical herbal collections and in Ancient and Medieval texts from the Mediterranean Region have been included in the database.</p> <p>Results</p> <p>1672 different uses, ranging from medicinal, to alimentary, ceremonial, veterinary, have been recorded for 474 species listed in the data base. Information is not uniformly spread over the Campanian territory; Sannio being the most studied geographical area and Cilento the least one. About 50 plants have been continuously used in the last three centuries in the cure of the same affections. A comparison with the uses reported for the same species in Ancient treatises shows that the origin of present ethnomedicine from old learned medical doctrines needs a case-by-case confirmation.</p> <p>Conclusion</p> <p>The database is flexible enough to represent a useful tool for researchers who need to store and compare present and previous ethnobotanical uses from Mediterranean Countries.</p

    2D seismic tomography of Somma-Vesuvius: Description of the experiment and preliminary results

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    A multidisciplinary project for the investigation of Mt. Vesuvius structure was started in 1993. The core of the project is represented by a high resolution seismic tomography study by using controlled and natural sources. The main research objective is to investigate the feeding system of the volcano and to retrieve details of the upper crustal structure in the area. A first 2D active seismic experiment was performed in May 1994, with the aim of studing the feasibility of using tomographic techniques for exploring the volcano interiors. Particularly, this experiment was designed to obtain information on the optimal sources-receivers configuration and on the depth extension of the volume sampled by shot-generated seismic waves. 66 three-component seismic stations and 16 single-component analogue instruments were installed by several Italian and French groups to record signals generated by three on-land, underground explosions. Sources and geophones were deployed along a 30-km NW-SE profile passing through the volcano crater. Receivers were placed at an average spacing of 250 m in the middle of the recording line and at 500 m outside. The arrival time data base was complemented by first P and S readings of microearthquakes which occurred in the recent past within the volcano. The first arrival data set was preliminarily used to determine the shallow structure of the volcano by applying Thurber's (1983) tomographic inversion technique. This analysis shows evidence for a high-velocity body which extends vertically from about 400 m below the crater down to at least 3000 m and for a shallow 300-500 m thick low-velocity cover which borders the edifice. Data from the distant shot show evidence for arrivals of deep reflected/converted phases and provide information on the deeper structure under the volcano. The results from the interpretation of 2D data are used for planning a 3D tomographic survey which will be carried out in 1996
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