48,336 research outputs found

    Using C-Tool to simulate soil carbon and radiocarbon development

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    Tho model framework C-TOOL was used to simulate soil carbon and radiocarbon development. A simple three-compartment model was sufficient for describing the data

    A survey of the effect of grooved runway operations on the wear of commercial airline tires

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    Effect of grooved runway operations on wear of commercial airline tire

    Hamiltonian Reduction of SL(2)SL(2)-theories at the Level of Correlators

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    Since the work of Bershadsky and Ooguri and Feigin and Frenkel it is well known that correlators of SL(2)SL(2) current algebra for admissible representations should reduce to correlators for conformal minimal models. A precise proposal for this relation has been given at the level of correlators: When SL(2)SL(2) primary fields are expressed as ϕj(zn,xn)\phi_j(z_n,x_n) with xnx_n being a variable to keep track of the SL(2)SL(2) representation multiplet (possibly infinitely dimensional for admissible representations), then the minimal model correlator is supposed to be obtained simply by putting all xn=znx_n=z_n. Although strong support for this has been presented, to the best of our understanding a direct, simple proof seems to be missing so in this paper we present one based on the free field Wakimoto construction and our previous study of that in the present context. We further verify that the explicit SL(2)SL(2) correlators we have published in a recent preprint reduce in the above way, up to a constant which we also calculate. We further discuss the relation to more standard formulations of hamiltonian reduction.Comment: 13 pages, LaTe

    Extended Superconformal Algebras from Classical and Quantum Hamiltonian Reduction

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    We consider the extended superconformal algebras of the Knizhnik-Bershadsky type with WW-algebra like composite operators occurring in the commutation relations, but with generators of conformal dimension 1,32\frac{3}{2} and 2, only. These have recently been neatly classified by several groups, and we emphasize the classification based on hamiltonian reduction of affine Lie superalgebras with even subalgebras Gsl(2)G\oplus sl(2). We reveiw the situation and improve on previous formulations by presenting generic and very compact expressions valid for all algebras, classical and quantum. Similarly generic and compact free field realizations are presented as are corresponding screening charges. Based on these a discussion of singular vectors is presented. (Based on talk by J.L. Petersen at the Int. Workshop on "String Theory, Quantum Gravity and the Unification of the Fundamental Interactions", Rome Sep. 21-26, 1992)Comment: 30 pages, NBI-HE-92-8

    European lessons for Green and Blue Services in The Netherlands

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    Green and Blue Services were developed in The Netherlands to reward farmers for the environmental services they provide to society. Especially the first initiatives were area specific, developed together with farmers and different from the national Agri-environmental scheme. In the PLUREL case study region Haaglanden, Green and Blue Services are seen as a strategy to strengthen agriculture in the urban fringe

    Survey of Australian father\u27s attitudes towards infant vaccination: Findings from the Australian Father\u27s Study

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    Objective: To investigate the attitudes of expectant Australian fathers towards vaccination, and to identify factors which may influence these attitudes. Methods: A cross-sectional survey study of 407 Australian men with expectant partners, mean age 30.4 (SD 6.7). Self reported attitude, level of knowledge and information resources accessed regarding pregnancy related issues. Participant demographics collected included: Age, number of children, relationship status, level of education, employment information and smoking status. Results: Majority (89%) of participants had a positive attitude towards infant vaccination, 9% felt neutral and 2% had negative attitudes. Positive attitudes towards vaccination were associated with lower self-reported knowledge of pregnancy issues but a higher likelihood of discussing pregnancy issues with health care providers rather than sourcing information from the internet (both p\u3c0.001). Conclusion: A majority of Australian expectant fathers have a positive attitude towards infant vaccination. Fathers with negative attitudes to vaccination self-reported higher levels of knowledge. They were more likely to obtain information from the Internet instead of healthcare staff. Implication for public health: Including fathers in health discussion with knowledgeable health care providers may result in increased vaccine uptake

    Directed flow, a signal for the phase transition in Relativistic Nuclear Collisions?

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    The sign change of the slope of the directed flow of baryons has been predicted as a signal for a first order phase transition within fluid dynamical calculations. Recently, the directed flow of identified particles has been measured by the STAR collaboration in the beam energy scan (BES) program. In this article, we examine the collision energy dependence of directed flow v1v_1 in fluid dynamical model descriptions of heavy ion collisions for sNN=320\sqrt{s_{NN}}=3-20 GeV. The first step is to reproduce the existing predictions within pure fluid dynamical calculations. As a second step we investigate the influence of the order of the phase transition on the anisotropic flow within a state-of-the-art hybrid approach that describes other global observables reasonably well. We find that, in the hybrid approach, there seems to be no sensitivity of the directed flow on the equation of state and in particular on the existence of a first order phase transition. In addition, we explore more subtle sensitivities like e.g. the Cooper-Frye transition criterion and discuss how momentum conservation and the definition of the event plane affects the results. At this point, none of our calculations matches qualitatively the behavior of the STAR data, the values of the slopes are always larger than in the data.Comment: 7 pages, 7 figure

    Assessing the climate impacts of Chinese dietary choices using a telecoupled global food trade and local land use framework

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    Global emissions trajectories developed to meet the 2⁰C temperature target are likely to rely on the widespread deployment of negative emissions technologies and/or the implementation of substantial terrestrial carbon sinks. Such technologies include afforestation, carbon capture and storage (CCS) and bioenergy with carbon capture and storage (BECCS), but mitigation options for agriculture appear limited. For example, using the Global Calculator tool (http://www.globalcalculator.org/), under a 2⁰C pathway, the ‘forests and other land use’ sector is projected to become a major carbon sink, reaching -15 GtCO2e yr-1 by 2050, compared to fossil emissions of 21 GtCO2e yr-1. At the same time, rates of agricultural emissions remain static at about 6 GtCO2e yr-1, despite increasing demands for crop and livestock production to meet the forecast dietary demands of the growing and increasingly wealthy global population. Emissions in the Global Calculator are sensitive to the assumed global diet, and particularly to the level and type of meat consumption, which in turn drive global land use patterns and agricultural emissions. Here we assess the potential to use a modified down-scaled Global Calculator methodology embedded within the telecoupled global food trade framework, to estimate the agricultural emissions and terrestrial carbon stock impacts in China and Brazil, arising from a plausible range of dietary choices in China. These dietary choices are linked via telecoupling mechanisms to Brazilian crop production (e.g. Brazilian soy for Chinese animal feed provision) and drive land and global market dynamics. ‘Spill-over’ impacts will also be assessed using the EU and Malawi as case studies

    Applications of cluster analysis in natural resources research

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