Feasibility of high-voltage systems for a very long drift in liquid argon TPCs

Designs of high-voltage (HV) systems for creating a drift electric field in liquid argon TPCs are reviewed. In ongoing experiments systems capable of approx. 100 kV are realised for a drift field of 0.5-1 kV/cm over a length of up to 1.5 m. Two of them having different approaches are presented: (1) the ICARUS-T600 detector having a system consisting of an external power supply, HV feedthroughs and resistive voltage degraders and (2) the ArDM-1t detector having a cryogenic Greinacher HV multiplier inside the liquid argon volume. For a giant scale liquid argon TPC, a system providing 2 MV may be required to attain a drift length of approx. 20 m. Feasibility of such a system is evaluated by extrapolating the existing designs.Comment: 8 pages, 13 figures, to appear in Proc. of 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba (Japan), March 201

On CY-LG correspondence for (0,2) toric models

We conjecture a description of the vertex (chiral) algebras of the (0,2) nonlinear sigma models on smooth quintic threefolds. We provide evidence in favor of the conjecture by connecting our algebras to the cohomology of a twisted chiral de Rham sheaf. We discuss CY/LG correspondence in this setting.Comment: 25 pages, reference added, typos corrected, to be published in Advances in Mathematic

The macroeconomics of delayed exchange-rate unification : theory and evidence from Tanzania

Parallel exchange-rate markets have often been dismissed by authorities as a nuisance or as the domain of a small group of economic saboteurs. Using Tanzania as a case study, the authors argue instead that these markets played a central macroeconomicrole in the 1970s and 1980s. They provide a rigorous macroeconomic analysis of the parallel foreign-exchange market and its fiscal implications. First, they investigate the evolution of that market in Tanzania from the mid-1960s to 1990. That period stretched from the adoption of exchange controls to macroeconomic collapse and then to subsequent reforms in the mid- to late 1980s. A reduced -form econometric equation (of a Dornbusch stock-flow model type) indicates that both trade and financial portfolio factors were important in determining the parallel premium, with trade determinants the parallel premium, with trade determinants dominating in the long run, as theory suggests. Then they investigate the fiscal impact of the parallel exchange-rate premium, an issue emphasized in the literature on exchange-rate unification. They construct a counterfactual simulation of fiscal and balance-of-payments flows under alternative assumptions about the indexing of those flows to the parallel and official exchange rate. They find that a more aggressive move toward exchange-rate unification would have already delivered a fiscal bonus by the mid-1980s. Accordingly, unification of the exchange rate would have reduced monetary growth and inflationary pressures. So, contrary to conventional advice often given in Africa and elsewhere, the case of Tanzania suggests that from a fiscal viewpoint there was no economic rationale for gradualism in exchange-rate unification and delay of a move toward convertibility.Economic Theory&Research,Banks&Banking Reform,Fiscal&Monetary Policy,Payment Systems&Infrastructure,Environmental Economics&Policies,Economic Theory&Research,Macroeconomic Management,Fiscal&Monetary Policy,Environmental Economics&Policies,Economic Stabilization

Three Hopf algebras from number theory, physics & topology, and their common background II: general categorical formulation

We consider three a priori totally different setups for Hopf algebras from number theory, mathematical physics and algebraic topology. These are the Hopf algebra of Goncharov for multiple zeta values, that of Connes-Kreimer for renormalization, and a Hopf algebra constructed by Baues to study double loop spaces. We show that these examples can be successively unified by considering simplicial objects, co-operads with multiplication and Feynman categories at the ultimate level. These considerations open the door to new constructions and reinterpretations of known constructions in a large common framework which is presented step-by-step with examples throughout. In this second part of two papers, we give the general categorical formulation

Lead-oxygen closed-loop battery system

Calculations show that battery can deliver up to 35 watt-hours per pound, conventional lead-acid batteries deliver 10 to 15 watt-hours per pound. Weight reduction is due to replacement of solid lead-peroxide electrodes with metal current-collector screen, catalyst, and Teflon membrane

Fourier Series Formalization in ACL2(r)

We formalize some basic properties of Fourier series in the logic of ACL2(r), which is a variant of ACL2 that supports reasoning about the real and complex numbers by way of non-standard analysis. More specifically, we extend a framework for formally evaluating definite integrals of real-valued, continuous functions using the Second Fundamental Theorem of Calculus. Our extended framework is also applied to functions containing free arguments. Using this framework, we are able to prove the orthogonality relationships between trigonometric functions, which are the essential properties in Fourier series analysis. The sum rule for definite integrals of indexed sums is also formalized by applying the extended framework along with the First Fundamental Theorem of Calculus and the sum rule for differentiation. The Fourier coefficient formulas of periodic functions are then formalized from the orthogonality relations and the sum rule for integration. Consequently, the uniqueness of Fourier sums is a straightforward corollary. We also present our formalization of the sum rule for definite integrals of infinite series in ACL2(r). Part of this task is to prove the Dini Uniform Convergence Theorem and the continuity of a limit function under certain conditions. A key technique in our proofs of these theorems is to apply the overspill principle from non-standard analysis.Comment: In Proceedings ACL2 2015, arXiv:1509.0552

La "démocratie technique" au pays de la démocratie directe : la Suisse et le débat sur les sciences de la vie

Paul de Brem Alain Kaufmann, vous êtes le directeur de l’Interface sciences-société de l’Université de Lausanne, un département de la présidence de l’université. Vous appartenez aussi au centre d’évaluation des choix technologiques de la Confédération suisse, qui conseille le parlement et le gouvernement et qui anime le débat public. La Suisse, comme on le sait, pratique la démocratie directe depuis longtemps, et les projets de loi font l’objet de longues négociations en amont. Dans ce pays, est-il encore nécessaire de disposer de lieux où la science et la technologie sont mises en débat et, si oui, quelle forme ce débat prend-il 

Testing of pear trees on their own roots in comparison with important used rootstocks under organic farming conditions with special regard to fire blight (E. amylovora)

Pear trees on their own roots are tested in comparison to grafted trees in growth and yield characteristics and with special regard to the tolerance to diseases, above all fire blight (Erwinia amylovora). In spring 2004 15 randomized trees of the cultivar 'Williams' from three variants (self rooted in vitro, self rooted long cuttings, grafted on Quince A) were planted in a pear orchard, which was heavily infected with fire blight (Erwinia amylovora) the previous years. The trees were left untreated. Growth and yield characteristics, plant diseases and tree losses were observed. After four years the in vitro self rooted trees were significantly more vigorous in growth than those grafted on quince A. The self rooted long cuttings were comparable in growth with grafts on quince, but showed high tree losses probably due to frost damages in the first winter one year after planting. However no infections with Erwinia amylovora could be observed so far. In a field trial with more cultivars and rootstock variants planted in 2006 at two organically managed sites more significant effects are expected in the next years