19,175 research outputs found

    Analysis of unmitigated large break loss of coolant accidents using MELCOR code

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    In the framework of severe accident research activity developed by ENEA, a MELCOR nodalization of a generic Pressurized Water Reactor of 900 MWe has been developed. The aim of this paper is to present the analysis of MELCOR code calculations concerning two independent unmitigated large break loss of coolant accident transients, occurring in the cited type of reactor. In particular, the analysis and comparison between the transients initiated by an unmitigated double-ended cold leg rupture and an unmitigated double-ended hot leg rupture in the loop 1 of the primary cooling system is presented herein. This activity has been performed focusing specifically on the in-vessel phenomenology that characterizes this kind of accidents. The analysis of the thermal-hydraulic transient phenomena and the core degradation phenomena is therefore here presented. The analysis of the calculated data shows the capability of the code to reproduce the phenomena typical of these transients and permits their phenomenological study. A first sequence of main events is here presented and shows that the cold leg break transient results faster than the hot leg break transient because of the position of the break. Further analyses are in progress to quantitatively assess the results of the code nodalization for accident management strategy definition and fission product source term evaluation

    Metabolic syndrome and the immunological affair with the blood-brain barrier

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    Copyright © 2015 Mauro, De Rosa, Marelli-Berg and Solito. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms

    Hemispherical power asymmetries in the WMAP 7-year low-resolution temperature and polarization maps

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    We test the hemispherical power asymmetry of the WMAP 7-year low-resolution temperature and polarization maps. We consider two natural estimators for such an asymmetry and exploit our implementation of an optimal angular power spectrum estimator for all the six CMB spectra. By scanning the whole sky through a sample of 24 directions, we search for asymmetries in the power spectra of the two hemispheres, comparing the results with Monte Carlo simulations drawn from the WMAP 7-year best-fit model. Our analysis extends previous results to the polarization sector. The level of asymmetry on the ILC temperature map is found to be compatible with previous results, whereas no significant asymmetry on the polarized spectra is detected. Moreover, we show that our results are only weakly affected by the a posteriori choice of the maximum multipole considered for the analysis. We also forecast the capability to detect dipole modulation by our methodology at Planck sensitivity.Comment: 7 pages, 9 figures. Accepted for publication in MNRA

    IIR Adaptive Filters for Detection of Gravitational Waves from Coalescing Binaries

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    In this paper we propose a new strategy for gravitational waves detection from coalescing binaries, using IIR Adaptive Line Enhancer (ALE) filters. This strategy is a classical hierarchical strategy in which the ALE filters have the role of triggers, used to select data chunks which may contain gravitational events, to be further analyzed with more refined optimal techniques, like the the classical Matched Filter Technique. After a direct comparison of the performances of ALE filters with the Wiener-Komolgoroff optimum filters (matched filters), necessary to discuss their performance and to evaluate the statistical limitation in their use as triggers, we performed a series of tests, demonstrating that these filters are quite promising both for the relatively small computational power needed and for the robustness of the algorithms used. The performed tests have shown a weak point of ALE filters, that we fixed by introducing a further strategy, based on a dynamic bank of ALE filters, running simultaneously, but started after fixed delay times. The results of this global trigger strategy seems to be very promising, and can be already used in the present interferometers, since it has the great advantage of requiring a quite small computational power and can easily run in real-time, in parallel with other data analysis algorithms.Comment: Accepted at SPIE: "Astronomical Telescopes and Instrumentation". 9 pages, 3 figure

    The qualitative assessment of responsiveness to environmental challenge in horses and ponies.

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    The responsiveness of 10 horses and 10 ponies to environmental challenge (represented by an open field test) was assessed using a qualitative approach based on free choice profiling methodology (FCP), which gives observers complete freedom to choose their own descriptive terms. Data were analysed with generalised Procrustes analysis (GPA), a multivariate statistical technique associated with FCP. A cross-validation of the outcomes of this approach to data recorded through quantitative behaviour analysis, and through a questionnaire given to the animals’ owner/riding instructor, was also performed using principal component analysis (PCA). Twelve undergraduate students generated their own descriptive vocabularies, by watching 20 horse/pony video clips lasting 2.5 min each. GPA showed that the consensus profile explained a high percentage of variation among the 12 observers, and differed significantly from the mean randomised profile ( p < 0.001). Two main dimensions of the consensus profile were identified, explaining 60% and 5.2% of the variation between animals, respectively. The 12 observer word charts interpreting these dimensions were semantically consistent, as they all converged towards the same meaning, albeit using different terms. The most used term to describe the positive end of axis 1 was ‘‘quiet’’, whereas ‘‘attentive’’ was the best positive descriptor of axis 2. The most frequently used descriptors for the negative ends of axes 1 and 2 were ‘‘nervous’’ and ‘‘bored’’, respectively. Thus, axis 1 was labelled as ‘‘quiet/nervous’’ and axis 2 was named as ‘‘attentive/bored’’. A marked effect of animal category was observed on the scores of the animals on the first dimension ( p < 0.001). Horses received significantly higher scores, and were thus assessed as more quiet and calm, than ponies. Conversely, ponies tended to receive lower scores on the second dimension ( p < 0.12), therefore they appeared less curious and attentive. The results of the PCA showed that the variables from different types of measurement clearly had meaningful relationships. For instance, the variables with the highest loading on the positive end of axis 1 were all indicative of tractable and docile animals, whereas axis 2 showed high loadings on the positive end for variables indicating attentive animals. Qualitative behaviour assessment proved to be an appropriate methodology for the study of horse behavioural responsiveness, in that it provided a multifaceted characterisation of horse behavioural expression that was in agreement with other quantitative and subjective assessments of the animals’ behaviour

    Influence of space allowance on the welfare of weaned buffalo (Bubalus Bubalis) calves

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    Twenty weaned female buffalo calves were used to evaluate the effect of space allowance in relation to their body surface area on a range of behavioural and physiological parameters. Body surface area in m2 was calculated as 0.12 body weight0.60. Ten calves received 50% of body surface as space allocation (Group 50), 10 others received 90% of body surface area (Group 90). Animals in Group 50 lay with a lower number of outstretched legs than calves in Group 90. Buffaloes from Group 50 were observed standing more frequently than animals from Group 90 ( P < 0.001). The proportions of idling ( P < 0.01) and lying idle observations ( P < 0.001) were higher for Group 90 than for Group 50. Group 90 performed a higher number of non-agonistic interactions than Group 50 ( P < 0.01), whereas the opposite was observed for the number of agonistic interactions ( P < 0.01). When exposed to open field testing, Group 50 animals displayed an increased duration of movement, number of galloping events and more vocalisation. Neither immune responses to phytohemagglutinin and ovalbumin nor the cortisol response to exogenous ACTH were affected by treatment. It was concluded that 50% of body surface area may be an inadequate space allowance for weaned calves

    Sustainability and welfare of Podolian cattle

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    The aim of the present study was to evaluate the sustainability and welfare of extensively farmed Podolian cattle. A trained interviewer visited 50 farms and filled in a checklist which included four cards corresponding to the following animal categories: calves, replacements, feeders and adults. The analysis of the farming system showed that animals were able to express their main behavioural patterns. In addition, recorded animal-related variables indicated that Podolian cattle could benefit from high standards of welfare. Sustainability of the Podolian farming system in terms of human edible returns was evaluated for two production systems producing 10-month-old calves (10 month) and 18-month-old young bulls (18 month), respectively. Edible returns for humans were low when all animal intakes were considered for both production systems. However, if returns were computed using not only the amount of food used by the animals but also consumable by humans, yields were much higher for 18-month systems [103% crude protein (CP) and 37.1% gross energy (GE)] and so high that they could not be computed for 10-month systems. These results indicate either a low degree of competition (18-month system) or no competition (10-month system) between humans and Podolian cattle. Perceptions of sustainability and welfare of Podolian cattle may promote a favourable positioning of products in premium-price markets and help preserving this breed and the related traditional farming system

    Housing system and welfare of buffalo (Bubalus bubalis) cows

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    Twenty-eight buffalo cows were used to evaluate the effect of housing system on a range of behavioural and physiological variables. Fourteen cows were group-housed in a loose open-sided barn with a concrete floor and 10 m2 per head as space allowance (group IS). Fourteen others were group-housed in a similar barn but they could also benefit from an outdoor yard with 500 m2 per head as space allowance, free access to potholes for wallowing and spontaneous vegetation (group TS). Animals were subjected to six sessions of instantaneous scan sampling at 10-day intervals. Behavioural variables were expressed as proportions of subjects observed in each category of posture and activity. Phytohaemagglutinin (PHA) was used to perform a skin test based on non-specific delayed type hypersensitivity, whereas 20 mg of ovalbumin were injected subcutaneously to evaluate humoral immune response. Blood samples for evaluation of cortisol concentration were collected immediately prior to exogenous porcine ACTH injection and 1, 2 and 4 h after. The metabolic status of the animals and milk production were also monitored. The proportion of idling animals was higher in group IS than in group TS (P< 0·001). More IS buffalo cows were observed eating at the manger than TS animals (P< 0·001). A higher proportion of TS animals were observed in the sun (P< 0·001). Grazing and bathing activities were recorded only for TS animals. Our findings suggest that buffalo cows kept in intensive conditions and having no access to ample yards and potholes may extend their periods of idling with negative effects on the state of welfare. Immune responses, metabolite concentrations and milk production were not affected by treatment, whereas cortisol levels were higher in IS animals (P< 0·05). The provision of a housing system similar to natural conditions was able to improve the welfare of buffalo cows as indicated by the expression of some species-specific natural behaviours. Such conditions were also associated with lower adrenal cortex response to ACTH injection, possibly as a consequence of the higher degree of initiative allowed to TS cows

    Design issues and experimental characterization of a continuously-tuned adaptive CMOS LNA

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    This paper presents the design implementation and experimental characterization of an adaptive Low Noise Amplifier (LNA) intended for multi-standard Radio Frequency (RF) wireless transceivers. The circuit —fabricated in a 90-nm CMOS technology— is a two-stage inductively degenerated common-source topology that combines PMOS varactors with programmable load to make the operation of the circuit continuously tunable. Practical design issues are analyzed, considering the effect of circuit parasitics associated to the chip package and integrated inductors, capacitors and varactors. Experimental measurements show a continuous tuning of NF and Sparameters within the 1.75-2.23GHz band, featuring NF19.6dB and IIP3> −9.8dBm, with a power dissipation < 23mW from a 1-V supply voltage.Ministerio de Ciencia e Innovación (FEDER) TEC2007-67247-C02-01/MICJunta de Andalucía, Consejo Regional de Innovación, ciencia y empresa TIC-253
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