7,075 research outputs found

    Bessel processes, the Brownian snake and super-Brownian motion

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    We prove that, both for the Brownian snake and for super-Brownian motion in dimension one, the historical path corresponding to the minimal spatial position is a Bessel process of dimension -5. We also discuss a spine decomposition for the Brownian snake conditioned on the minimizing path.Comment: Submitted to the special volume of S\'eminaire de Probabilit\'es in memory of Marc Yo

    Quenched convergence of a sequence of superprocesses in R^d among Poissonian obstacles

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    We prove a convergence theorem for a sequence of super-Brownian motions moving among hard Poissonian obstacles, when the intensity of the obstacles grows to infinity but their diameters shrink to zero in an appropriate manner. The superprocesses are shown to converge in probability for the law P\mathbf{P} of the obstacles, and P\mathbf{P}-almost surely for a subsequence, towards a superprocess with underlying spatial motion given by Brownian motion and (inhomogeneous) branching mechanism ψ(u,x)\psi(u,x) of the form ψ(u,x)=u2+Îș(x)u\psi(u,x)= u^2+ \kappa(x)u, where Îș(x)\kappa(x) depends on the density of the obstacles. This work draws on similar questions for a single Brownian motion. In the course of the proof, we establish precise estimates for integrals of functions over the Wiener sausage, which are of independent interest.Comment: 22 page

    Large pion pole in Z_{S}^{MOM}/Z_{P}^{MOM} from Wilson action data

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    We show that, contrarily to recent claims, data from the Wilson (unimproved) fermionic action at three different beta values demonstrate the presence of a large Goldstone boson contribution in the quark pseudoscalar vertex, quantitatively close to our previous estimate based on the SW action with c_{SW}=1.769. We show that discretisation errors on Z_{S}^{MOM}/Z_{P}^{MOM} seem to be much smaller than the Goldstone pole contribution over a very large range of momenta. The subtraction of this non perturbative contribution leads to numbers close to one-loop BPT.Comment: 12 pages, 5 figures, laTeX, minor corrections of typos, beta dependence made more explicit, added one table giving the contribution of the Goldstone vs. the discretisation errors at ap=

    Stable carbon isotopic compositions of individual aromatic hydrocarbons as source and age indicators in oils from western Australian basins

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    The present study aims to establish the factors controlling the stable carbon isotopic compositions (d13C) of individual aromatic hydrocarbons analysed by compound specific isotope analysis (CSIA) in crude oils from western Australian petroleum basins of varying age and facies type. This paper reports d13C values of individual aromatic hydrocarbons, like alkylbenzenes, alkylnaphthalenes, alkylphenanthrenes and methylated biphenyls. The main aims are to confirm the origin (source) and age of these oils based on CSIA of selected aromatic compounds and to understand why the Sofer plot is ineffective in establishing the source of western Australian petroleum systems. The bulk d13C of saturated and aromatic hydrocarbon fractions of crude oils have been previously used to differentiate sources, however, many Australian crude oils are not classified correctly using this method. The oils were classified as marine by the d13C values of individual aromatic compounds and as terrigenous based on the bulk d13C data (Sofer plot). The oils where the d13C values of 1,6-DMN and 1,2,5-TMN isomers are most negative are indicative of a marine source, whereas oils with a less negative values for the 1,6-DMN and 1,2,5-TMN isomers are derived from marine source rocks that contain a significant terrigenous component. Similarly, oils with the least negative d13C values for the 1-MP and 1,9-DMP isomers reflect varying inputs of terrigenous organic matter to the their marine source rocks. Plots of P/DBT and Pr/Ph concentration ratios versus d13C values of DMP, 1,6-DMN, 1,2,5-TMN, 1-MP and 1,9-MP are constructed to establish the relative amount of terrigenous organic matter contributing to the source rock of a series of marine oils. The ratios of P/DBT and Pr/Ph plotted against the d13C values of the aromatic isomers (such as 1,6-DMN, 1,2,5-TMN, 1-MP and 1,9-MP) provide a novel and convenient way to discriminate crude oils derived from different source rocks that contain varying amounts of marine and terrigenous organic matter

    Harnessing Demographic Differences in Organizations: What Moderates the Effects of Workplace Diversity?

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    To account for the double-edged nature of demographic workplace diversity (i.e. relational demography, work group diversity, and organizational diversity) effects on social integration, performance and well-being related variables, research has moved away from simple main effect approaches and started examining variables that moderate these effects. While there is no shortage of primary studies of the conditions under which diversity leads to positive or negative outcomes, it remains unclear which contingency factors make it work. Using the Categorization-Elaboration Model (van Knippenberg, DeDreu, & Homan 2004) as our theoretical lens we review variables moderating the effects of workplace diversity on social integration, performance and well-being outcomes, focusing on factors that organizations and managers have control over (i.e. strategy, unit design, HR, leadership, climate/culture, and individual differences). We point out avenues for future research and conclude with practical implications

    Artefacts and <A2> power corrections : revisiting the MOM Z_psi and Z_V

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    We extract the power corrections due to the A^2 condensate in the overlap quark propagator (vector part of the inverse propagator Z_psi). The results are consistent with the previous gluon analysis. The role of artefacts is extensively discussed.Comment: 33 pages, 5 figure

    Canine tick-borne pathogens in Cyprus and a unique canine case of multiple co-infections

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    Canine tick-borne pathogens such as Ehrlichia canis and Hepatozoon canis are widespread in the Mediterranean basin but have never been reported or investigated in Cyprus. We describe herein the presence of canine tick-borne pathogens in three dogs with clinical signs compatible with vector-borne diseases from Paphos area of Cyprus. Molecular and phylogenetic analysis revealed the presence of E. canis, Anaplasma platys, H. canis, Babesia vogeli and Mycoplasma haemocanis in Cyprus. One dog co-infected with E. canis, H. canis, B. vogeli and M. haemocanis is, to the best of our knowledge, the first report of this multiple co-infection in dogs. The tick-borne pathogens reported in the current study should be considered in the differential diagnoses in dogs exposed to ticks in Cyprus

    Detecting Determinacy in Prolog Programs: 22nd International Conference, ICLP 2006, Seattle, WA, USA, August 17-20, 2006. Proceedings

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    In program development it is useful to know that a call to a Prolog program will not inadvertently leave a choice-point on the stack. Determinacy inference has been proposed for solving this problem yet the analysis was found to be wanting in that it could not infer determinacy conditions for programs that contained cuts or applied certain tests to select a clause. This paper shows how to remedy these serious deficiencies. It also addresses the problem of identifying those predicates which can be rewritten in a more deterministic fashion. To this end, a radically new form of determinacy inference is introduced, which is founded on ideas in ccp, that is capable of reasoning about the way bindings imposed by a rightmost goal can make a leftmost goal deterministic

    Examining stakeholder involvement in the context of top-down marine protected area governance: the case of the Sept-Îles National Nature Reserve (Brittany, France)

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    Marine protected areas (MPAs) are important yet complex conservation tools that can be difficult to govern and manage. In France, the State manages protected areas with national status, but consults communities and users when making decisions. How can the governance of an MPA be improved while respecting the framework imposed on it by State regulations? This study focuses on the Sept-Îles National Nature Reserve (RĂ©serve naturelle nationale, or RNN), located in northern Brittany (France) and renowned for its natural heritage, particularly for its seabird conservation efforts. Its management methods are provided for by the French Environmental Code, and are structured around an Advisory Committee, a Scientific Council, and a designated manager. Any change in the functioning of this committee must comply with the provisions of French law. Following a decree to extend the perimeter of the RNN, there was the opportunity to reassess the functioning of the current governance structure the RNN Sept-Îles and to define its strengths and weaknesses so that these may be addressed as the RNN grows. Various stakeholders – for the most part members of the Advisory Committee – were engaged through semi-structured interviews, guided by the principles of good governance. This study found that the current structure of the Advisory Committee is not aligned with the French Environmental Code and proposes new working groups that could offer stakeholders more opportunities for participation. There were issues of representation, communication, and power struggles within the Advisory Committee and highlights a distinct lack of young people within the governance structure of the RNN, which poses questions about its future. This is one of the first studies in France to propose an alternative governance structure involving more RNN stakeholders that can fit into the current framework imposed by State regulations
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