348 research outputs found

    TOPOLOGY OF THE ITALIAN AIRPORT NETWORK: A SCALE-FREE SMALL-WORLD NETWORK WITH A FRACTAL STRUCTURE?

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    Abstract In this paper, for the first time we analyze the structure of the Italian Airport Network (IAN) looking at it as a mathematical graph and investigate its topological properties. We find that it has very remarkable features, being like a scalefree network, since both the degree and the ‘‘betweenness centrality’’ distributions follow a typical power-law known in literature as a Double Pareto Law. From a careful analysis of the data, the Italian Airport Network turns out to have a self-similar structure. In short, it is characterized by a fractal nature, whose typical dimensions can be easily determined from the values of the power-law scaling exponents. Moreover, we show that, according to the period examined, these distributions exhibit a number of interesting features, such as the existence of some ‘‘hubs’’, i.e. in the graph theory’s jargon, nodes with a very large number of links, and others most probably associated with geographical constraints. Also, we find that the IAN can be classified as a small-world network because the average distance between reachable pairs of airports grows at most as the logarithm of the number of airports. The IAN does not show evidence of ‘‘communities’’ and this result could be the underlying reason behind the smallness of the value of the clustering coefficient, which is related to the probability that two nearest neighbors of a randomly chosen airport are connected

    Tratamiento oportuno de mordida cruzada en dentición mixta

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    Introducción: La mordida cruzada o mordida invertida es un trastorno del crecimiento dentario que involucra no más de dos piezas dentarias por discrepancia local o mal posición. Se debe corregir en dentición temprana o mixta. Las causas pueden ser traumatismos de dientes temporarios que desplazan a los permanentes en desarrollo, falta de diastemas, pérdida de longitud del arco, extracciones tempranas, caries. Requiere de interconsulta y tratamiento en forma conjunta con fonoaudiólogo y otorrinolaringólogo en casos de compromiso de vías respiratorias.Facultad de Odontologí

    Tratamiento oportuno de mordida cruzada en dentición mixta

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    Introducción: La mordida cruzada o mordida invertida es un trastorno del crecimiento dentario que involucra no más de dos piezas dentarias por discrepancia local o mal posición. Se debe corregir en dentición temprana o mixta. Las causas pueden ser traumatismos de dientes temporarios que desplazan a los permanentes en desarrollo, falta de diastemas, pérdida de longitud del arco, extracciones tempranas, caries. Requiere de interconsulta y tratamiento en forma conjunta con fonoaudiólogo y otorrinolaringólogo en casos de compromiso de vías respiratorias.Facultad de Odontologí

    Status of Salerno Laboratory (Measurements in Nuclear Emulsion)

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    A report on the analysis work in the Salerno Emulsion Laboratory is presented. It is related to the search for nu_mu->nu_tau oscillations in CHORUS experiment, the calibrations in the WANF (West Area Neutrino Facility) at Cern and tests and preparation for new experiments.Comment: Proc. The First International Workshop of Nuclear Emulsion Techniques (12-24 June 1998, Nagoya, Japan), 15 pages, 11 figure

    Short-Facelift Approach in Temporal Artery Biopsy: Is It Safe?

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    Giant cell arteritis (GCA) is a quite common panarteritis of the elderly that affects medium- and large-size arteries. Despite the increasing role of imaging with advancing technology, the gold standard for the diagnosis of GCA is still the temporal artery biopsy. A described complication of superficial temporal artery biopsy (STAB), for which incidence is not clear, is the accidental damage of the frontal branch of the facial nerve. In this paper, we described the short-scar facelift surgical approach for STAB on 23 consecutive patients who underwent unilateral superficial temporal artery biopsy for GCA suspicion. We collected data in terms of postoperative complications, biopsy specimen length, biopsy result and cosmetic appearance of the scar. In our experience, this surgical approach combines the advantage of avoiding incisions within the dangerous anatomical area, minimizing the risk of facial nerve damage, with an acceptable complication rate and a good final aesthetic result which avoids visible scarring

    Valor nutritivo del grano y del forraje de líneas F4 Y F5 de tricepiro (Triticum x Secale x Trigopyrum)

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    En la región Semiárida Pampeana a los trigopiros y triticales les ha seguido el tricepiro, cereal sintético de uso forrajero que combina los genomas de trigo, centeno y agropiro. El grano de este cereal es usado en la alimentación animal y podría utilizarse en la alimentación humana. En el presente trabajo se analizaron líneas segregantes (F4 y F5) de tricepiros con relación a otros cereales forrajeros. Se evaluó la materia seca y el contenido proteico del forraje en tres fechas de corte y al composición química del grano (proteína, calcio, magnesio, fósforo y cenizas). No se encontró diferencia significativa en la producción total de la materia seca tanto entre como dentro de especies, si bien los centenos presentaron una producción mayor en el primer corte, los triticales en las dos primeras fechas y el trigopiro al final del ciclo. Por su parte, los tricepiros ofrecieron una producción de materia seca más equilibrada. El contenido proteico presentó diferencia entre las distintas especies y genotipos en las tres fechas de corte, disminuyendo el porcentaje hacia final del ciclo, no haciéndose limitante para el uso ganadero. En la composición química de grano, el material segregante de tricepiro arrojó valores de proteína muy superiores al requerido para su uso en la elaboración de galletitas. Cuando se disponga de semilla suficiente de líneas estabilizadas se deberá repetir el análisis de la composición química del grano y su relación con el rendimiento. No obstante, de la presente evaluación se desprende que la selección de genotipos con mejor llenado de grano permitiría disminuir el contenido de proteína, haciéndolo más apto para el uso de harinas horneables.Director: Ing. Agr. Héctor Paccapelo, Cátedra de Genética y Mejoramieno de Plantas y Animales.Co-Director: Ing. Agr. Teresa Sanchez, Cátedra de Química II

    Comparison of meat quality characteristics and oxidative stability between conventional and free-range chickens

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    The aim of this research was to evaluate quality traits and oxidative stability of meat products from free range (FR) and conventionally (C) raised chickens as they actually reach consumers in the Italian retail market. FR female and male chickens (n=1500 + 1500), medium growing Isa strain, were raised under commercial conditions for 56 (1.8 kg of live wt.) and 70 d (3.1 kg of live wt.), respectively; C female and male birds (n=5000 + 5000) were a fast growing hybrid (Ross 708) and were separately raised for 39 (1.9 kg of live wt.) and 50 d (3.1 kg of live wt.), respectively. A total of 96 chickens (equally divided by production system and sex) were slaughtered into 2 separate sessions, to obtain the main two commercial categories (rotisserie and cut-up, respectively). After slaughtering, 12 carcasses of each treatment group were randomly selected and used to assess quality properties, chemical composition and oxidation stability of breast and leg meat. C birds had dramatic higher carcass and breast meat yield, whereas FR had higher wing and leg yields. FR birds exhibited higher water holding capacity in both breast and leg meat. Although shear force did not differ in breast meat, legs from FR birds were tougher. Fatty acid composition of FR breast and thigh meat of both categories were characterized by a higher PUFA n-6-/n-3 ratio. In general, a low lipid oxidation level (peroxide value (PV) < 1.3 meq O2/kg of lipid and thiobarbituric acid reactive substances (TBARs) < 0.2 mg MDA/kg of sample) was found in breast and legs, regardless of the commercial category. However, the C system significantly increased PV in rotisserie thigh meat, whereas FR led to a significantly higher TBARs in breast meat. Our results demonstrated that free range can modify the properties of chicken meat and also highlighted the importance of the animal genetic background to select nutritional strategies to improve meat quality traits and oxidative stability in poultry

    Constraining dark energy models using the lookback time to galaxy clusters and the age of the universe

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    An impressive amount of different astrophysical data converges towards the picture of a spatially flat universe undergoing a today phase of accelerated expansion. The nature of the dark energy dominating the energy content of the universe is still unknown and a lot of different scenarios are viable candidates to explain cosmic acceleration. Most of the methods employed to test these cosmological models are essentially based on distance measurements to a particular class of objects. A different method, based on the lookback time to galaxy clusters and the age of the universe, is used here. In particular, we constrain the characterizing parameters of three classes of dark energy cosmological models to see whether they are in agreement with this kind of data, based on time measurements rather than distance observations.Comment: 13 pages, 8 figures, accepted for publication on Physical Review
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