17,888 research outputs found

    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

    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

    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

    Acyclic orientations with path constraints

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    Many well-known combinatorial optimization problems can be stated over the set of acyclic orientations of an undirected graph. For example, acyclic orientations with certain diameter constraints are closely related to the optimal solutions of the vertex coloring and frequency assignment problems. In this paper we introduce a linear programming formulation of acyclic orientations with path constraints, and discuss its use in the solution of the vertex coloring problem and some versions of the frequency assignment problem. A study of the polytope associated with the formulation is presented, including proofs of which constraints of the formulation are facet-defining and the introduction of new classes of valid inequalities

    Scaling of variables and the relation between noncommutative parameters in Noncommutative Quantum Mechanics

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    We consider Noncommutative Quantum Mechanics with phase space noncommutativity. In particular, we show that a scaling of variables leaves the noncommutative algebra invariant, so that only the self-consistent effective parameters of the model are physically relevant. We also discuss the recently proposed relation of direct proportionality between the noncommutative parameters, showing that it has a limited applicability.Comment: Revtex4, 4 pages; version to match the published on
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