3,676 research outputs found

    The relative concentration of visible and dark matter in clusters of galaxies

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    [Abridged] We consider two clusters (A496 and Coma) that are representative of the two classes of cool-core and non-cool-core clusters. We first refer to a two-component dynamical model that ignores the contribution from the galaxy density distribution and study the condition of hydrostatic equilibrium for the hot intracluster medium (ICM) under the assumption of spherical symmetry, in the presence of dark matter. We model the ICM density distribution in terms of a standard β\beta-model with β=2/3\beta=2/3, i.e. with a distribution similar to that of a regular isothermal sphere (RIS), and fit the observed X-ray brightness profiles. With the explicit purpose of ignoring cosmological arguments, we na\"ively assume that dark matter, if present, has an analogous density distribution, with the freedom of two different density and length scales. The relative distribution of visible and dark matter is then derived by fitting the temperature data for the ICM under conditions of hydrostatic equilibrium. For both clusters, we find that dark matter is more concentrated with respect to visible matter. We then test whether the conclusion changes significantly when dark matter is taken to be distributed according to cosmologically favored density profiles and when the contribution of the mass contained in galaxies is taken into account. Although the qualitative conclusions remain unchanged, we find that the contribution of galaxies to the mass budget is more important than generally assumed. We also show that, without resorting to additional information on the small scale, it is not possible to tell whether a density cusp is present or absent in these systems. [Abridged]Comment: 13 pages, 3 figures, accepted for publication in Il Nuovo Cimento

    Effects of heat stress on reproductive activity in dairy cows bred in the Potenza district

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    The effect of heat stress on the reproductive performance in dairy cows reared in Apennines areas of Southern Italy was evaluated. Reproductive parameters obtained from three farms during the period 2007-2012 were related to either season variations or the temperature-humidity index (THI), i.e., a complex climate parameter obtained by the maximum temperature and minimum relative humidity. The THI was able to assess the HS effects on parameters as conception rate on an annual basis (CRY) (R=-0.437; P <0.01) but was less efficient for parameters as the conception rate (CR). Whereas (i) CRY is influenced by both heat detection rate (HDR) and CR; (ii) an indirect analysis detected a significant (P< 0.001) reduction in the HDR along with THI increase; and (iii) CR was only partially affected by either THI or season, it follows that the main cause of reduced fertility in the farms surveyed was the HDR. The number of days open was significantly larger in the animals calved from January to July than in those calved between August and December (163±33 vs 123±36; P< 0.001); this increase may be because of the rescue of reproduction activity in the cows calved during the former period coincides with heat stress occurrence

    The use of alternative energies in hatcheries: an application of Life Cycle Analysis

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    Fish production requires great efforts and energies and causes different impacts/effects on the ecosystems. The development of aquaculture is possible, in the medium and long term, only if this is done responsibly, and if the production is reached from both an economic and environmental point of view. In our study we have worked on fry production using 1.5 g sized Dicentrarchus labrax obtained rearing larvae for 120 days after the hatching of the eggs

    Il Codex Iuris Canonici e le culture

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    Il contributo, che confluir\ue0 in una raccolta di studi per celebrare i venticinque anni dalla promulgazione del "Codex Iuris Canonici", si occupa di un tema, quello dell'inculturazione, assai poco trattato dalla scienza giuridica canonistica. Si analizza anzitutto il problema dell'apertura in generale della Chiesa alle culture dal punto di vista teorico, specie delle sue radici teologiche. Ci si concentra poi sulle ripercussioni ed i riflessi di tale apertura nelle disposizioni del Codice vigente per la Chiesa cattolica latina del 1983, il quale, pur ponendosi quale frutto ed espressione prevalente della cultura europea occidentale, \ue8 tuttavia destinato ad un'applicazione potenzialmente universale: dunque i suoi disposti dovranno essere osservati anche da comunit\ue0 cristiane che non hanno condiviso quella storia europea, antica e recente, di cui la codificazione reca evidenti tracce. Diverse sono, per\uf2, come si constata, le fonti del diritto canonico particolare che permettono, grazie ai molteplici spazi ad esse dischiusi dal diritto codiciale, alle culture diverse da quella dominante di penetrare all'interno dello "ius Ecclesiae", plasmandolo ed adattandolo. Ci si addentra quindi nell'indagine di alcuni settori normativi in cui l'esigenza di inculturazione \ue8 pi\uf9 avvertita e pressante: il diritto che disciplina l'organizzazione ecclesiastica e le strutture in cui si articola la "societas Ecclesiae", il diritto missionario, il diritto liturgico. Particolare attenzione \ue8 dedicata al diritto matrimoniale, sia nel suo versante sostanziale (relativo all'istituto ed alla sua configurazione giuridica), sia in quello processuale (attese anche le recenti novit\ue0 normative in ordine al processo matrimoniale canonico). Il saggio si intrattiene altres\uec sulle prospettive interordinamentali, esaminando il rinvio che il diritto canonico effettua al diritto secolare come forma di inculturazione, nonch\ue9 testando l'ingresso nello "ius Ecclesiae" del diritto di Chiese e comunit\ue0 ecclesiali separate per concludere con riflessioni sull'apertura a culture non cristiane

    Giurisdizione matrimoniale ecclesiastica e poteri autoritativi della magistratura italiana

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    SOMMARIO: 1. La sentenza n. 22827 del 2004 della Cassazione penale italiana - 2. Il segreto \u201cprofessionale\u201d del ministro di culto/giudice ecclesiastico - 3. Indipendenza e sovranit\ue0 della Chiesa nel suo ordine e attivit\ue0 dei tribunali ecclesiastici in materia matrimoniale. La libert\ue0 della giurisdizione della Chiesa e la repressione dei reati da parte dello Stato - 4. Il ricorso al giudice italiano in ambito giudiziario matrimoniale canonico. Fisionomia e caratteri del processo canonico di nullit\ue0 del vincolo e illeciti penali in esso perpetrabili - 5. Quali i possibili effetti delle \u201cinterferenze\u201d della giustizia italiana sul processo canonico? - 6. Giurisdizione della Chiesa e giurisdizione dello Stato nell\u2019ottica della reciproca collaborazione tra Stato italiano e Chiesa cattolica per la promozione dell\u2019uomo e il bene del paese

    General calibration methodology for a combined Horton-SCS infiltration scheme in flash flood modeling

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    Abstract. Flood forecasting undergoes a constant evolution, becoming more and more demanding about the models used for hydrologic simulations. The advantages of developing distributed or semi-distributed models have currently been made clear. Now the importance of using continuous distributed modeling emerges. A proper schematization of the infiltration process is vital to these types of models. Many popular infiltration schemes, reliable and easy to implement, are too simplistic for the development of continuous hydrologic models. On the other hand, the unavailability of detailed and descriptive information on soil properties often limits the implementation of complete infiltration schemes. In this work, a combination between the Soil Conservation Service Curve Number method (SCS-CN) and a method derived from Horton equation is proposed in order to overcome the inherent limits of the two schemes. The SCS-CN method is easily applicable on large areas, but has structural limitations. The Horton-like methods present parameters that, though measurable to a point, are difficult to achieve a reliable estimate at catchment scale. The objective of this work is to overcome these limits by proposing a calibration procedure which maintains the large applicability of the SCS-CN method as well as the continuous description of the infiltration process given by the Horton's equation suitably modified. The estimation of the parameters of the modified Horton method is carried out using a formal analogy with the SCS-CN method under specific conditions. Some applications, at catchment scale within a distributed model, are presented

    Electric sail static structural analysis with finite element approach

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    The propulsive characteristics of an Electric Solar Wind Sail are usually evaluated using a simplified model in which all the sail tethers are coplanar and form a sort of rigid disk. However, the three-dimensional arrangement of the tethers is fundamental information in the study of the spacecraft performance, and must be accounted for in refined mission analyses. In this paper, a Finite Element approach is chosen to estimate the deflected shape of the tethers, thus allowing important information on the structural response of the sail to be obtained. A parametric code is developed to perform a static analysis of an Electric Solar Wind Sail, whose requirements are given in terms of payload mass and spacecraft characteristic acceleration. In particular, the tether structural response is investigated using three different beam models, which are compared in terms of accuracy and computational efficiency. The analysis is specialized to the noteworthy case of a Sun-facing sail that is placed at a distance of one astronomical unit from the Sun. The numerical results, which concern a set of possible sail configurations, are compared with those taken from analytical models
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