Symbolic powers of monomial ideals and Cohen-Macaulay vertex-weighted digraphs

In this paper we study irreducible representations and symbolic Rees algebras of monomial ideals. Then we examine edge ideals associated to vertex-weighted oriented graphs. These are digraphs having no oriented cycles of length two with weights on the vertices. For a monomial ideal with no embedded primes we classify the normality of its symbolic Rees algebra in terms of its primary components. If the primary components of a monomial ideal are normal, we present a simple procedure to compute its symbolic Rees algebra using Hilbert bases, and give necessary and sufficient conditions for the equality between its ordinary and symbolic powers. We give an effective characterization of the Cohen--Macaulay vertex-weighted oriented forests. For edge ideals of transitive weighted oriented graphs we show that Alexander duality holds. It is shown that edge ideals of weighted acyclic tournaments are Cohen--Macaulay and satisfy Alexander dualityComment: Special volume dedicated to Professor Antonio Campillo, Springer, to appea

Compression of Surface Electromyographic Signals Using Two-Dimensional Techniques

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Epidemiology of Salmonella in two different finishing swine barns in Brazil

Many finishing barns in Brazil have lamina d\u27agua , a continuous water flow at the back of solid-floored adjacent pens. Prevalence of Salmonella shedding and environmental contamination in finishing barns with lamina d\u27agua and without it were assessed through a cross sectional study conducted in 6 farms. No difference was found between the two systems. Sixteen Salmonella strains were isolated from 4 farms, comprising 6 serotypes: S. Agona, S. Typhimurium, S. Senftenberg, S. Sandiego, S. Rissen and S. Javiana. Serotypes varied among farms and differed from those recently identified in Brazil. Epidemiology of salmonella in swine farms is complex and might vary between farms or even between barns in a same farm

Antimicrobial resistance patterns of Salmonella isolated from finishing pigs and environmental samples

The aim of this study was to determine the antimicrobial resistance patterns of Salmonella isolates from pigs and environmental samples collected from modern swine facilities in Brazil. Sixteen samples from a total of 1,026 were positive to Salmonella and six serotypes were identified: Salmonella Typhimurium (1), Salmonella Agona (5), Salmonella Sandiego (4), Salmonella Rissen (1), Salmonella Senftenberg ( 4) and Salmonella Javiana (I). Resistance patterns were different among serotypes, but different isolates from a single serotype had the same antimicrobial pattern. The highest percentage of resistance was to tetracycline (100%), streptomycin (100%), nalidixic acid (100%), cefotaxime (12.5) and tobramycin ( 12.5). All serotypes were I 00% susceptible to ceftriaxone, norfloxacin, ciprofloxacin, ampicillin, gentamycin and chloramphenicol. Intermediate resistance to neomycin (93.5%), amikacin (12.5%) and trimethoprim (12.5%) was seen. The high resistance to tetracycline and streptomycin may be due to its extensive use in pig production

Potencial genético da aveia, como produtora de grãos no sul do Brasil

Yield and other agronomic traits were studied in six experiments with oats (Avena sativa L.) established in the Southern Brazil, during the years 1982 to 1984. The grain yield and hectoliter wight in different genotypes showed high progress; however, plant stature and heading time did not change in the last three years. The results suggest that plant breeding programmes should release new genotypes to increase stability and yield potential. O rendimento de grãos e outros caracteres de importância agronômica foram estudados em seis experimentos de aveia estabelecidos na região sul do Brasil, entre os anos de 1982 a 1984. O rendimento de grãos e o peso do hectolitro nos diferentes genótipos demonstraram um alto progresso; entretanto, a estatura e o ciclo de desenvolvimento de planta não apresentaram alterações nos últimos três anos. Os resultados sugerem que os programas de melhoramento devem continuar criando e testando novos genótipos anualmente, com o objetivo de incrementar a estabilidade e o potencial de rendimento de grãos.

Differential branching fraction and angular analysis of the decay B0→K∗0μ+μ−

The angular distribution and differential branching fraction of the decay B 0→ K ∗0 μ + μ − are studied using a data sample, collected by the LHCb experiment in pp collisions at s√=7 TeV, corresponding to an integrated luminosity of 1.0 fb−1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions

Measurement of the relative rate of prompt χc0, χc1 and χc2 production at √s=7TeV

Prompt production of charmonium χc0, χc1 and χc2 mesons is studied using proton-proton collisions at the LHC at a centre-of-mass energy of √s=7TeV. The χc mesons are identified through their decay to J/ψγ, with J/ψ→μ+mu− using photons that converted in the detector. A data sample, corresponding to an integrated luminosity of 1.0fb−1 collected by the LHCb detector, is used to measure the relative prompt production rate of χc1 and χc2 in the rapidity range 2.0<y<4.5 as a function of the J/ψ transverse momentum from 3 to 20 GeV/c. First evidence for χc0 meson production at a hadron collider is also presented

Observation of the decay Bc→J/ψK+K−π+B_c \rightarrow J/\psi K^+ K^- \pi^+

The decay $B_c\rightarrow J/\psi K^+ K^- \pi^+$ is observed for the first time, using proton-proton collisions collected with the LHCb detector corresponding to an integrated luminosity of 3fb$^{-1}$. A signal yield of $78\pm14$ decays is reported with a significance of 6.2 standard deviations. The ratio of the branching fraction of \B_c \rightarrow J/\psi K^+ K^- \pi^+ decays to that of $B_c \rightarrow J/\psi \pi^+$ decays is measured to be $0.53\pm 0.10\pm0.05$, where the first uncertainty is statistical and the second is systematic.Comment: 18 pages, 2 figure