2,467 research outputs found

    A new paradigm of governance for a carbon-pricing system

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    Throughout its life, the United Nations has played a pioneering role in the world of ideas. COP21 – also known as Paris 2015 – shows the path for the United Nations to establish a new governance that will enforce the compliance of a new planetary carbon-pricing system. Maintaining global warming below 2 °C means implementing an efficient carbon-pricing system, supported by effective measures promoting a green energy transition. A planetary carbon governance yields a number of new insights that include the following: (1) a bonus-malus system with a fixed signal price for carbon, (2) a planetary carbon market that will gather existing regional carbon markets, (3) a hybrid carbon-pricing system linking a carbon tax and a carbon market for advanced countries and (4) a support mechanism for emerging and developing countries to assist them with a carbon-pricing system. This new governance will promote an energy transition plan. In the COP21 context, responsible policymaking requires key characteristics for the enforcement of a successful planetary carbon-pricing system

    Journée Georges Aubert

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    From Paper to Praxis: Advancing the Discipline in a Small College Environment

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    This article proposes the advancement of communications discipline at a small college in Georgia. In the small liberal arts college, one tends to find many faculty members who have had little or no experience with departments of communication. It is also plausible that some approaches to the study of communication may be deemed unsuitable in a small liberal arts setting. To meet the demands of the millennial technological environment, the dean of the college decided to reexamine the communication major in terms of its scope and function on campus. The proposals for the advancement of the discipline are discussed herein

    Random trees between two walls: Exact partition function

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    We derive the exact partition function for a discrete model of random trees embedded in a one-dimensional space. These trees have vertices labeled by integers representing their position in the target space, with the SOS constraint that adjacent vertices have labels differing by +1 or -1. A non-trivial partition function is obtained whenever the target space is bounded by walls. We concentrate on the two cases where the target space is (i) the half-line bounded by a wall at the origin or (ii) a segment bounded by two walls at a finite distance. The general solution has a soliton-like structure involving elliptic functions. We derive the corresponding continuum scaling limit which takes the remarkable form of the Weierstrass p-function with constrained periods. These results are used to analyze the probability for an evolving population spreading in one dimension to attain the boundary of a given domain with the geometry of the target (i) or (ii). They also translate, via suitable bijections, into generating functions for bounded planar graphs.Comment: 25 pages, 7 figures, tex, harvmac, epsf; accepted version; main modifications in Sect. 5-6 and conclusio

    The Rook-Brauer Algebra

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    We introduce an associative algebra RBk(x) that has a basis of rook-Brauer diagrams. These diagrams correspond to partial matchings on 2k vertices. The rook-Brauer algebra contains the group algebra of the symmetric group, the Brauer algebra, and the rook monoid algebra as subalgebras. We show that the basis of RBk(x) is generated by special diagrams si, ti (1 \u3c= i \u3c k) and pj (1 \u3c= j \u3c= k), where the si are the simple transpositions that generated the symmetric group Sk, the ti are the contraction maps which generate the Brauer algebra Bk(x), the pj are the projection maps that generate the rook monoid Rk. We prove that for a positive integer n, the algebra RBk(n+1) is the centralizer algebra of the orthogonal group O(n) acting on the k-fold tensor power of the sum of its 1-dimensional trivial module and n-dimensional defining module

    Confluence of geodesic paths and separating loops in large planar quadrangulations

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    We consider planar quadrangulations with three marked vertices and discuss the geometry of triangles made of three geodesic paths joining them. We also study the geometry of minimal separating loops, i.e. paths of minimal length among all closed paths passing by one of the three vertices and separating the two others in the quadrangulation. We concentrate on the universal scaling limit of large quadrangulations, also known as the Brownian map, where pairs of geodesic paths or minimal separating loops have common parts of non-zero macroscopic length. This is the phenomenon of confluence, which distinguishes the geometry of random quadrangulations from that of smooth surfaces. We characterize the universal probability distribution for the lengths of these common parts.Comment: 48 pages, 33 color figures. Final version, with one concluding paragraph and one reference added, and several other small correction

    Development of q-PCR approaches to assess water quality: Effects of cadmium on gene expression of the diatom Eolimna minima

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    This study was undertaken to develop molecular tools to assess water quality using diatoms as the biological model. Molecular approaches were designed following the development of a rapid and easy RNA extraction method suited to diatoms and the sequencing of genes involved in mitochondrial and photosystem metabolism. Secondly the impact of cadmium was evaluated at the genetic level by q-PCR on 9 genes of interest after exposure of Eolimna minima diatom populations cultured in suspension under controlled laboratory conditions. Their growth kinetics and Cd bioaccumulation were followed.Population growth rates revealed the high impact of Cd at 100μg/L with total inhibition of growth. These results are linked to the high bioaccumulation values calculated after 14 days of exposure, 57.0±6.3μg. Cd/g. dw and 734.1±70μg. Cd/g. dw for exposures of 10 and 100μg. Cd/L respectively.Genetic responses revealed the impact of Cd on the mitochondrial metabolism and the chloroplast photosystem of E. minima exposed to 10 and 100μg. Cd/L with induction of cox1, 12S, d1 and psaA after 7 days of exposure for the concentration of 100μg. Cd/L and of nad5, d1 and psaA after 14 days of exposure for both conditions.This is the first reported use of q-PCR for the assessment of toxic pollution on benthic river diatoms. The results obtained presage interesting perspectives, but the techniques developed need to be optimized before the design of new water quality diagnosis tools for use on natural biofilms

    Localized versus itinerant magnetic moments in Na0.72CoO2

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    Based on experimental 59Co-NMR data in the temperature range between 0.1 and 300 K, we address the problem of the character of the Co 3d-electron based magnetism in Na0.7CoO2. Temperature dependent 59Co-NMR spectra reveal different Co environments below 300 K and their differentiation increases with decreasing temperature. We show that the 23Na- and 59Co-NMR data may consistently be interpreted by assuming that below room temperature the Co 3d-electrons are itinerant. Their magnetic interaction appears to favor an antiferromagnetic coupling, and we identify a substantial orbital contribution corb to the d-electron susceptibility. At low temperatures corb seems to acquire some temperature dependence, suggesting an increasing influence of spin-orbit coupling. The temperature dependence of the spin-lattice relaxation rate T1-1(T) confirms significant variations in the dynamics of this electronic subsystem between 200 and 300K, as previously suggested. Below 200 K, Na0.7CoO2 may be viewed as a weak antiferromagnet with TN below 1 K but this scenario still leaves a number of open questions.Comment: 8.7 pages, 6 Figures, submitted to Phys. Rev.

    White Lines and 3d-Occupancy for the 3d Transition-Metal Oxides

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    Electron energy-loss spectrometry was employed to measure the white lines at the L23 absorption edges of the 3d transition-metal oxides and lithium transition-metal oxides. The white-line ratio (L3/L2) was found to increase between d^0 and d^5 and decrease between d^5 and d^10, consistent with previous results for the transition metals and their oxides. The intensities of the white lines, normalized to the post-edge background, are linear for the 3d transition-metal oxides and lithium transition-metal oxides. An empirical correlation between normalized white-line intensity and 3d occupancy is established. It provides a method for measuring changes in the 3d-state occupancy. As an example, this empirical relationship is used to measure changes in the transition-metal valences of Li_{1-x}Ni_{0.8}Co_{0.2}O_2 in the range of 0 < x < 0.64. In these experiments the 3d occupancy of the nickel ion decreased upon lithium deintercalation, while the cobalt valence remained constant.Comment: 6 pages, 7 figure
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