18,963 research outputs found

    Feeding of Conserved Forage - Implications to Grassland Management and Production

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    This review will focus on the use of conserved forages in pastoral dairy farm systems; especially on their conservation as an aid to good grazing management during periods of rapid pasture growth, and on their consumption as an aid to good feeding management and grazing management during periods of slow pasture growth. Conservation of pasture, in order to move it from one time to another later time, always involves “costs”, either financial expenditure or physical losses (of dry matter/quality) or both, which must be evaluated in the whole system. Most of the data is drawn from New Zealand and Australia, with some from England and Ireland. The topic has been reviewed before (e.g. Rogers, 1984 and 1985; Leaver, 1985; Phillips, 1988; Mayne, 1991; Stockdale et al., 1997), but the present review will put greater emphasis on the effects on pasture management and on the whole pastoral system, and on recent results, because the cows’ ability to respond to supplementary feeds is now larger than it used to be, as a result of steady genetic improvement in milk producing capacities. In recent years there has been marked increase in supplement use on pasture based dairy farming systems in New Zealand often driven by perceived limitations to production increases in existing systems rather than profit (Attrill and Miller 1996). This review attempts to identify, and discuss, the factors involved in supplementary feeding (i.e. the responses of cows and farming systems to extra feed) to enable sustainable increases in productivity and profitability on pastoral based systems

    Isotopic difference in the heteronuclear loss rate in a two-species surface trap

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    We have realized a two-species mirror-magneto-optical trap containing a mixture of 87^{87}Rb (85^{85}Rb) and 133^{133}Cs atoms. Using this trap, we have measured the heteronuclear collisional loss rate βRb−Cs′\beta_{Rb-Cs}' due to intra-species cold collisions. We find a distinct difference in the magnitude and intensity dependence of βRb−Cs′\beta_{Rb-Cs}' for the two isotopes 87^{87}Rb and 85^{85}Rb which we attribute to the different ground-state hyperfine splitting energies of the two isotopes.Comment: 4 pages, 2 figure

    Use of 2G coated conductors for efficient shielding of DC magnetic fields

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    This paper reports the results of an experimental investigation of the performance of two types of magnetic screens assembled from YBa2Cu3O7-d (YBCO) coated conductors. Since effective screening of the axial DC magnetic field requires the unimpeded flow of an azimuthal persistent current, we demonstrate a configuration of a screening shell made out of standard YBCO coated conductor capable to accomplish that. The screen allows the persistent current to flow in the predominantly azimuthal direction at a temperature of 77 K. The persistent screen, incorporating a single layer of superconducting film, can attenuate an external magnetic field of up to 5 mT by more than an order of magnitude. For comparison purposes, another type of screen which incorporates low critical temperature quasi-persistent joints was also built. The shielding technique we describe here appears to be especially promising for the realization of large scale high-Tc superconducting screens.Comment: 8 pages, 3 figure

    Intercultural communicative competence in foreign language education: Questions of theory, practice and research

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    Language teaching and learning has undergone a ‘cultural turn’ since the emergence of ‘the Communicative Approach’ and ‘Communicative Language Teaching’ in the 1970s. The earlier study of language, which involved the study of literary and other texts, had neglected the need for ‘communicative competence’— the ability to use language in socially appropriate ways, often operationalised as ‘politeness’. However, perhaps as a consequence of globalisation, new technologies, and mass economic and refugee migration, it has become clear that communicative language teaching too, with its focus on sociolinguistic appropriateness and politeness, is inadequate to the task of teaching for communication. This new social context requires consideration of the ways in which people of different languages — including language learners themselves — think and act, and how this might impact on successful communication and interaction. The ‘cultural turn’ – the introduction of ‘intercultural competence’ to complement ‘communicative competence’ – has further refined the notion of what it is to be competent for communication with speakers of different languages. Teachers and learners now need to be ‘aware’ of other people’s ‘cultures’ as well as their own, and therefore, the term ‘intercultural (communicative) competence’ has emerged, along with other terms such as ‘cultural awareness’ and ‘transnational competence’

    Parabolic resonances and instabilities in near-integrable two degrees of freedom Hamiltonian flows

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    When an integrable two-degrees-of-freedom Hamiltonian system possessing a circle of parabolic fixed points is perturbed, a parabolic resonance occurs. It is proved that its occurrence is generic for one parameter families (co-dimension one phenomenon) of near-integrable, t.d.o. systems. Numerical experiments indicate that the motion near a parabolic resonance exhibits new type of chaotic behavior which includes instabilities in some directions and long trapping times in others. Moreover, in a degenerate case, near a {\it flat parabolic resonance}, large scale instabilities appear. A model arising from an atmospherical study is shown to exhibit flat parabolic resonance. This supplies a simple mechanism for the transport of particles with {\it small} (i.e. atmospherically relevant) initial velocities from the vicinity of the equator to high latitudes. A modification of the model which allows the development of atmospherical jets unfolds the degeneracy, yet traces of the flat instabilities are clearly observed

    Young people's uses of celebrity: Class, gender and 'improper' celebrity

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    This is an Author's Accepted Manuscript of an article published in Discourse: Studies in the Cultural Politics of Education, 34(1), 2013, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/01596306.2012.698865.In this article, we explore the question of how celebrity operates in young people's everyday lives, thus contributing to the urgent need to address celebrity's social function. Drawing on data from three studies in England on young people's perspectives on their educational and work futures, we show how celebrity operates as a classed and gendered discursive device within young people's identity work. We illustrate how young people draw upon class and gender distinctions that circulate within celebrity discourses (proper/improper, deserving/undeserving, talented/talentless and respectable/tacky) as they construct their own identities in relation to notions of work, aspiration and achievement. We argue that these distinctions operate as part of neoliberal demands to produce oneself as a ‘subject of value’. However, some participants produced readings that show ambivalence and even resistance to these dominant discourses. Young people's responses to celebrity are shown to relate to their own class and gender position.The Arts and Humanities Research Council, the British Academy, the Economic and Social Research Council, and the UK Resource Centre for Women in Science Engineering and Technology

    Non--Newtonian viscosity of interacting Brownian particles: comparison of theory and data

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    A recent first-principles approach to the non-linear rheology of dense colloidal suspensions is evaluated and compared to simulation results of sheared systems close to their glass transitions. The predicted scenario of a universal transition of the structural dynamics between yielding of glasses and non-Newtonian (shear-thinning) fluid flow appears well obeyed, and calculations within simplified models rationalize the data over variations in shear rate and viscosity of up to 3 decades.Comment: 6 pages, 2 figures; J. Phys. Condens. Matter to be published (Jan. 2003
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