1,838 research outputs found

    Geografia e televisione: dagli spazi locali agli spazi globali

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    Il rapporto tra geografia e televisione \ue8 un campo di studio ancora troppo poco esplorato. La comunicazione televisiva ha portato alla globalizzazione dei mercati e delle idee e, contemporaneamente, ha rafforzato le culture locali. La domanda \ue8 allora, per i geografi, se la televisione pu\uf2 aiutare ad abbattere le frontiere o se, al contrario, contribuisce a rafforzare i confini determinati da vincoli di identit\ue0 culturale. The relationship between Geography and Television is a field of study still too little explored. The television communication has led to the globalization of markets and of ideas and, simultaneously, has reinforced local cultures The question is then, to geographers, if television can help to tear down the borders or whether, on the contrary, contributes to strengthen the boundaries affected by ties of cultural identity

    Thermodynamic behaviour and structural properties of an aqueous sodium chloride solution upon supercooling

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    We present the results of a molecular dynamics simulation study of thermodynamic and structural properties upon supercooling of a low concentration sodium chloride solution in TIP4P water and the comparison with the corresponding bulk quantities. We study the isotherms and the isochores for both the aqueous solution and bulk water. The comparison of the phase diagrams shows that thermodynamic properties of the solution are not merely shifted with respect to the bulk. Moreover, from the analysis of the thermodynamic curves, both the spinodal line and the temperatures of maximum density curve can be calculated. The spinodal line appears not to be influenced by the presence of ions at the chosen concentration, while the temperatures of maximum density curve displays both a mild shift in temperature and a shape modification with respect to bulk. Signatures of the presence of a liquid-liquid critical point are found in the aqueous solution. By analysing the water-ion radial distribution functions of the aqueous solution we observe that upon changing density, structural modifications appear close to the spinodal. For low temperatures additional modifications appear also for densities close to that corresponding to a low density configurational energy minimum.Comment: 10 pages, 13 figures, 2 tables. To be published in J. Chem. Phy

    Canonical Derivations with Negative Application Conditions

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    Using graph transformations to specify the dynamics of distributed systems and networks, we require a precise understanding of concurrency. Negative application conditions (NACs) are an essential means for controlling the application of rules, extending our ability to model complex systems. A classical notion of concurrency in graph transformation is based on shift equivalence and its representation by canonical derivations, i.e., normal forms of the shift operation anticipating independent steps. These concepts are lifted to graph transformation systems with NACs and it is shown that canonical derivations exist for so-called incremental NACs

    Tolerance and efficacy of preventive gastrostomy feeding in pediatric oncology

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    BackgroundMalnutrition in pediatric oncology remains underestimated, although having a negative impact on outcome. Enteral nutrition (EN) using percutaneous endoscopic gastrostomy (PEG) may prevent or reverse malnutrition consequences. We aimed to evaluate both efficacy and safety of early EN during tumors treatment in children. Procedures Medical records of pediatric patients having a PEG tube inserted between 1995 and 2009 were retrospectively reviewed. We compared type and incidence of complications in Group 1, including 74 patients suffering from cancer, and control Group 2, including 57 patients with neurological impairment. Efficacy of EN was evaluated through nutritional parameters [Z-scores weight for height (W/H) and height for age (H/A)], post-operative complications and relapse rates. Statistical significance was set for P < 0.05. Results PEG tolerance was similar in both groups, as shown by comparable complication rates (62% vs. 76%, NS). EN allowed improvement or stabilization of Z-score W/H in 76% of oncologic patients. The final height loss was lower (−0.5 vs. −1.2 SD of Z-scores H/A) when EN was started at the beginning of the oncologic treatment. In bone tumors, EN prevented weight loss during chemotherapy, and tended to lessen surgical complications, relapses and deaths. Conclusions Early gastrostomy feeding represents a relatively safe way to prevent malnutrition in children with cancer, and might play a role in bone tumors oncological outcome. Further prospective studies are needed to confirm these results and assess the impact of EN and PEG on quality of life

    In Vitro Evaluation of an Active Heat-and-Moisture Exchanger: The Hygrovent Gold

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    BACKGROUND: To improve the heat and humidification that can be achieved with aheat-and-moisture exchanger (HME),a hybrid active (ie,adds heat and water) HME,the Hygrovent Gold,was developed. We evaluated in vitro the performance of theHygrovent Gold. METHODS: We tested the Hygrovent Gold (with and without its supplemental heat andmoisture options activated),the Hygrobac,and the Hygrovent S. We measured theabsolute humidity,using a test lung ventilated at minute volumes of 5,10,and15 L/min,in normothermic (expired temperature 34 degrees C) and hypothermic(expired temperature 28 degrees C) conditions. We also measured the HMEs' flowresistance and weight after 24 h and 48 h. RESULTS: In its active mode the Hygrovent Gold provided the highest absolutehumidity,independent of minute volume,in both normothermia and hypothermia. Therespective normothermia and hypothermia absolute humidity values at 10 L/min were36.3 + 1.3 mg/L and 27.1 + 1.0 mg/L with the active Hygrovent Gold,33.9 + 0.5mg/L and 24.2 + 0.8 mg/L with the passive Hygrovent Gold,33.8 + 0.56 mg/L and24.4 + 0.4 mg/L with the Hygrobac,and 33.9 + 0.8 mg/L and 24.6 + 0.6 mg/L withthe Hygrovent S. The efficiency of the tested HMEs did not change over time. At24 h and 48 h the increase in weight and flow resistance was highest in theactive Hygrovent Gold. CONCLUSIONS: The passive Hygrovent Gold provided adequate heat and moisture innormothermia,but the active Hygrovent Gold provided the highest humidity,inboth normothermia and hypothermia

    Graphical Encoding of a Spatial Logic for the pi-Calculus

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    This paper extends our graph-based approach to the verification of spatial properties of π-calculus specifications. The mechanism is based on an encoding for mobile calculi where each process is mapped into a graph (with interfaces) such that the denotation is fully abstract with respect to the usual structural congruence, i.e., two processes are equivalent exactly when the corresponding encodings yield isomorphic graphs. Behavioral and structural properties of π-calculus processes expressed in a spatial logic can then be verified on the graphical encoding of a process rather than on its textual representation. In this paper we introduce a modal logic for graphs and define a translation of spatial formulae such that a process verifies a spatial formula exactly when its graphical representation verifies the translated modal graph formula

    Stars in the Silurian sky : Echinoderm holdfasts from the Carnic Alps, Austria

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    A small collection of echinoderm holdfasts from the Ludlow Cardiola Formation of the Carnic Alps (Austria) contains a wide range of morphologies as a response of environmental adaptation. In general, the holdfasts have a globous and massive dome-like profile with several processes arranged in a sub-radial disposition, so to create a sort of 'star-like' outline. A small central depression is common but not present on all specimens. The distinctive holdfasts are preserved in an iron-rich phase, documenting a substitution that has also affected other non-echinoderm calcareous material

    Smooth tensionful higher-codimensional brane worlds with bulk and brane form fields

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    Completely regular tensionful codimension-n brane world solutions are discussed, where the core of the brane is chosen to be a thin codimension-(n-1) shell in an infinite volume flat bulk, and an Einstein-Hilbert term localized on the brane is included (Dvali-Gabadadze-Porrati models). In order to support such localized sources we enrich the vacuum structure of the brane by the inclusion of localized form fields. We find that phenomenological constraints on the size of the internal core seem to impose an upper bound to the brane tension. Finite transverse-volume smooth solutions are also discussed.Comment: 1+14 pages, 2 figures; section 2.3 improved, typos corrected and references added. Published versio

    Aspects of Quantum Gravity in Cosmology

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    We review some aspects of quantum gravity in the context of cosmology. In particular, we focus on models with a phenomenology accessible to current and near-future observations, as the early Universe might be our only chance to peep through the quantum gravity realm.Comment: 15 pages, 1 figure. Invited review for Modern Physics Letter A. Version 2: minor typos corrected, few references adde
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