3,943 research outputs found

    Emerging agents to combat complicated and resistant infections: focus on ceftobiprole

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    Antimicrobial resistance is a global concern. Over the past few years, considerable efforts and resources have been expended to detect, monitor, and understand at the basic level the many different facets of emerging and increasing resistance. Development of new antimicrobial agents has been matched by the development of new mechanisms of resistance by bacteria. Current antibiotics act at a variety of sites within the target bacteria, including the cross-linking enzymes in the cell wall, various ribosomal enzymes, nucleic acid polymerases, and folate synthesis. Ceftobiprole is a novel parenteral cephalosporin with high affinity for most penicillin-binding proteins, including the mecA product penicillin-binding protein 2a, rendering it active against methicillin-resistant staphylococci. Its in vitro activity against staphylococci and multiresistant pneumococci, combined with its Gram-negative spectrum comparable to that of other extended-spectrum cephalosporins, its stability against a wide range of beta-lactamases, and its pharmacokinetic and safety profiles make ceftobiprole an attractive and well tolerated new antimicrobial agent. The US Food and Drug Administration granted ceftobiprole medocaril fast-track status in 2003 for the treatment of complicated skin infections and skin structure infections due to methicillin-resistant staphylococci, and subsequently extended this to treatment of hospital-acquired pneumonia, including ventilator-associated pneumonia due to suspected or proven methicillin-resistant Staphylococcus aureus

    Dealing with residual energy when transmitting data in energy-constrained capacitated networks

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    This paper addresses several problems relating to the energy available after the transmission of a given amount of data in a capacitated network. The arcs have an associated parameter representing the energy consumed during the transmission along the arc and the nodes have limited power to transmit data. In the first part of the paper, we consider the problem of designing a path which maximizes the minimum of the residual energy remaining at the nodes. After formulating the problem and proving the main theoretical results, a polynomial time algorithm is proposed based on computing maxmin paths in a sequence of non-capacitated networks. In the second part of the paper, the problem of obtaining a quickest path in this context is analyzed. First, the bi-objective variant of this problem is considered in which we aim to minimize the transmission time and to maximize the minimum residual energy. An exact polynomial time algorithm is proposed to find a minimal complete set of efficient solutions which amounts to solving shortest path problems. Second, the problem of computing an energy-constrained quickest path which guarantees at least a given residual energy at the nodes is reformulated as a variant of the energy-constrained quickest path problem. The algorithms are tested on a set of benchmark problems providing the optimal solution or the Pareto front within reasonable computing times

    Variaciones sedimentarias durante el Eoceno medio en la sierra de Andía (Navarra)

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    In this paper, tkie stratigraphical and lithological character- istics of the Middle Eocene are established, in the Sierra de Andia (Navarra, Spain). Examples of the cross-stratification are described and the directional data analyzed. A study of the basin evolution is elaborated. It is pro- posed a correlation with the youngest sediments of the Sierra de Urbasa, situated more to the West

    Jet shapes in ep collisions at HERA

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    New measurements of the jet shape in ep collisions at HERA using the k_T-cluster jet algorithm are presented.Comment: 7 pages, 3 figures; plenary talk given at the 3rd UK Phenomenology Workshop on HERA Physics, Durham, UK, September 199

    Seedling vigor variation among 80 recombinant chromosome substitution lines (RCSL) of barley (Hordeum vulgare)

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    del Pozo, A (del Pozo, Alejandro). Univ Talca, Fac Ciencias Agr, Talca, Chile.Seedling vigor of 80 recombinant chromosome substitution lines (RCSL) of barley (Hordeum vulgare). Cien. Inv. Agr. 38 (1): 137-147. The seedling vigor of 80 barley recombinant chromosome substitution lines (RCSLs) was measured for selecting high seedling vigor genotypes. The RCSLs were derived from a cross between H. vulgare subsp. spontaneum and H. vulgare subsp. vulgare 'Harrington'. The work was carried out under greenhouse conditions during the summer of 2008. The experimental design was an alpha lattice with 3 replicates. In each replicate, 40 plants were established, distributed in eight polyethylene pots containing sand as substrate, which were fertilized an irrigated. The emergence of seedlings, number of leaves and shoots, dry matter of leaves, shoots and roots and leaf area of fully expanded leaves were measured. In addition, growth indices were calculated: emergence rate, leaf appearance rate, relative leaf expansion rate, relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and the allometric coefficient (K) between root and shoot thy matter. All calculated indices varied significantly among genotypes (P <= 0.05) and some RCSLs showed better early vigor associated traits than 'Harrington'. The dry matter accumulation 30 DAS (when the experiment ended) was significant and positively correlated with the RGR (r=0.61; P <= 0.05) and NAR (r=0.41; P <= 0.05). The K coefficient was negatively correlated with NAR (r=-0.40, P <= 0.05). The genotypes with the greatest seminal vigor were the RCSLs 45, 92, 112 and 'Harrington', whereas the RCSLs 5, 19,47 and 121 presented the lowest seminal vigor

    Symmetries in Fluctuations Far from Equilibrium

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    Fluctuations arise universally in Nature as a reflection of the discrete microscopic world at the macroscopic level. Despite their apparent noisy origin, fluctuations encode fundamental aspects of the physics of the system at hand, crucial to understand irreversibility and nonequilibrium behavior. In order to sustain a given fluctuation, a system traverses a precise optimal path in phase space. Here we show that by demanding invariance of optimal paths under symmetry transformations, new and general fluctuation relations valid arbitrarily far from equilibrium are unveiled. This opens an unexplored route toward a deeper understanding of nonequilibrium physics by bringing symmetry principles to the realm of fluctuations. We illustrate this concept studying symmetries of the current distribution out of equilibrium. In particular we derive an isometric fluctuation relation which links in a strikingly simple manner the probabilities of any pair of isometric current fluctuations. This relation, which results from the time-reversibility of the dynamics, includes as a particular instance the Gallavotti-Cohen fluctuation theorem in this context but adds a completely new perspective on the high level of symmetry imposed by time-reversibility on the statistics of nonequilibrium fluctuations. The new symmetry implies remarkable hierarchies of equations for the current cumulants and the nonlinear response coefficients, going far beyond Onsager's reciprocity relations and Green-Kubo formulae. We confirm the validity of the new symmetry relation in extensive numerical simulations, and suggest that the idea of symmetry in fluctuations as invariance of optimal paths has far-reaching consequences in diverse fields.Comment: 8 pages, 4 figure
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