Interpolation of Non-abelian Lattice Gauge Fields

We propose a method for interpolating non-abelian lattice gauge fields to the continuum, or to a finer lattice, which satisfies the properties of (i) transverse continuity, (ii) (lattice) rotation and translation covariance, (iii) gauge covariance, (iv) locality. These are the properties required for use in our earlier proposal for non-perturbative formulation and simulation of chiral gauge theories.Comment: A few typos corrected, a reference and a clarifying comment added. To appear in Nuclear Physics B. 16 pages, LateX, 1 figure. This interpolation scheme is intended for use in our formulation of lattice chiral gauge theory, Nucl. Phys. B455 (1990) 287, hep-ph/950633

The SseC translocon component in Salmonella enterica serovar Typhimurium is chaperoned by SscA

Background: Salmonella enterica is a causative agent of foodborne gastroenteritis and the systemic disease known as typhoid fever. This bacterium uses two type three secretion systems (T3SSs) to translocate protein effectors into host cells to manipulate cellular function. Salmonella pathogenicity island (SPI)-2 encodes a T3SS required for intracellular survival of the pathogen. Genes in SPI-2 include apparatus components, secreted effectors and chaperones that bind to secreted cargo to coordinate their release from the bacterial cell. Although the effector repertoire secreted by the SPI-2 T3SS is large, only three virulence-associated chaperones have been characterized. Results: Here we report that SscA is the chaperone for the SseC translocon component. We show that SscA and SseC interact in bacterial cells and that deletion of sscA results in a loss of SseC secretion, which compromises intracellular replication and leads to a loss of competitive fitness in mice. Conclusions: This work completes the characterization of the chaperone complement within SPI-2 and identifies SscA as the chaperone for the SseC translocon

Tycho Brahe's supernova: light from centuries past

The light curve of SN 1572 is described in the terms used nowadays to characterize SNeIa. By assembling the records of the observations done in 1572--74 and evaluating their uncertainties, it is possible to recover the light curve and the color evolution of this supernova. It is found that, within the SNe Ia family, the event should have been a SNIa with a normal rate of decline, its stretch factor being {\it s} $\sim$ 0.9. Visual light curve near maximum, late--time decline and the color evolution sustain this conclusion. After correcting for extinction, the luminosity of this supernova is found to be M$_{V}$ $=$ --19.58 --5 log (D/3.5 kpc) $\pm$ 0.42.Comment: 28 pages, 3 figures, 3 tables. submitted to ApJ (Main Journal

The origin of the cosmic gamma-ray background in the MeV range

There has been much debate about the origin of the diffuse $\gamma$--ray background in the MeV range. At lower energies, AGNs and Seyfert galaxies can explain the background, but not above $\simeq$0.3 MeV. Beyond $\sim$10 MeV blazars appear to account for the flux observed. That leaves an unexplained gap for which different candidates have been proposed, including annihilations of WIMPS. One candidate are Type Ia supernovae (SNe Ia). Early studies concluded that they were able to account for the $\gamma$--ray background in the gap, while later work attributed a significantly lower contribution to them. All those estimates were based on SN Ia explosion models which did not reflect the full 3D hydrodynamics of SNe Ia explosions. In addition, new measurements obtained since 2010 have provided new, direct estimates of high-z SNe Ia rates beyond $z\sim$2. We take into account these new advances to see the predicted contribution to the gamma--ray background. We use here a wide variety of explosion models and a plethora of new measurements of SNe Ia rates. SNe Ia still fall short of the observed background. Only for a fit, which would imply $\sim$150\% systematic error in detecting SNe Ia events, do the theoretical predictions approach the observed fluxes. This fit is, however, at odds at the highest redshifts with recent SN Ia rates estimates. Other astrophysical sources such as FSRQs do match the observed flux levels in the MeV regime, while SNe Ia make up to 30--50\% of the observed flux.Comment: 40 pages, 13 Figures, accepted to be published in Ap

An algebraic approach to the prefix model analysis of binary trie structures and set intersection algorithms

AbstractThe trie, or digital tree, is a standard data structure for representing sets of strings over a given finite alphabet. Since Knuth's original work (1973), these data structures have been extensively studied and analyzed. In this paper, we present an algebraic approach to the analysis of average storage and average time required by the retrieval algorithms of trie structures under the prefix model. This approach extends the work of Flajolet et al. for other models which, unlike the prefix model, assume that no key in a sample set is the prefix of another. As the main application, we analyze the average running time of two algorithms for computing set intersections

The role of promotion tools used in the Spanish campaign to promote new lamb meat cuts

Aim of study: The first purpose of the present study was to investigate the level of recall of the adverting campaign promoting the new lamb meat cuts. The second objective was to investigate which promotion tools are more important to consumers and retailers.Area of study: This study took place in the city of Zaragoza, where lamb meat promotional activities have been conducted at three different levels: generic promotion of the sector, Regulatory Council of Ternasco de Aragón promotion campaign and producer brand promotion.Material and methods: Data was collected through personal questionnaires (401 consumers and 55 retailers).Main results: Results suggest that the promotion campaign has not contributed as much as expected to spread the knowledge of the new lamb cuts among consumers. Both consumers and retailers attached more importance to in-store marketing promotional tools. Three consumers segments were identified based on promotion tools preferences. Comparing between consumers and butchers’ opinion the only significant difference was found in using internet and social network as a promotional tool.Research highlights: A general trend has been observed since the majority of consumers and retailers consider that the most important promotions tools are those conducted inside the point of sale. On the view of these results, it could be better for future campaigns to increase promotional effort inside the point of sale, where consumers make their final purchase choice

Measurement of the Bs0-Bs0 oscillation frequency δms in Bs0→Ds-(3)π decays

The Bs0-Bs0 oscillation frequency δms is measured with 36 pb-1 of data collected in pp collisions at s=7TeV by the LHCb experiment at the Large Hadron Collider. A total of 1381 Bs0→Ds-π+ and Bs0→Ds-π+π-π + signal decays are reconstructed, with average decay time resolutions of 44 fs and 36 fs, respectively. An oscillation signal with a statistical significance of 4.6σ is observed. The measured oscillation frequency is δm s=17.63±0.11(stat)±0.02(syst)ps -1

A New Lattice Action for Studying Topological Charge

We propose a new lattice action for non-abelian gauge theories, which will reduce short-range lattice artifacts in the computation of the topological susceptibility. The standard Wilson action is replaced by the Wilson action of a gauge covariant interpolation of the original fields to a finer lattice. If the latter is fine enough, the action of all configurations with non-zero topological charge will satisfy the continuum bound. As a simpler example we consider the $O(3)$ $\sigma$-model in two dimensions, where a numerical analysis of discretized continuum instantons indicates that a finer lattice with half the lattice spacing of the original is enough to satisfy the continuum bound.Comment: 12 pages, LateX, 1 figur

Movimientos verticales diarios de larvas de peces en estadío pre-flexión asociados a las praderas de Posidonia oceanica

Habitat complexity is a strong determinant of fish assemblage structure. Enhanced food resources and protection from predators are generally considered the main benefits of vegetated areas. We investigated the diel and vertical movements of preflexion fish larvae within and above the leaf canopy of Posidonia oceanica to determine if it acts as an important habitat for larval stage fish. Samples were taken with moored plankton nets during the night and day at two depths (13 and 15 m) over five consecutive days in July 2000 in the Marine Protected Area off Tabarca Island (Spain, SW Mediterranean Sea). In total, 353 fish larvae were captured. The most abundant taxa were Sardinella aurita, Sparidae, Engraulis encrasicolus and Gobiidae. Sparidae were more abundant within the leaf canopy during the day but increased in waters 2 m above the canopy at night. In contrast, Sardinella aurita were present throughout the entire water column during both the day and night. We conclude that the P. oceanica leaf canopy is important as a transitional shelter for the early stage larvae of some demersal fish species.El tipo de hábitat determina la estructura del poblamiento larvario de peces. Los principales beneficios que proporciona un hábitat con vegetación son el incremento de las fuentes de alimento y una mayor protección frente a los predadores. Este estudio se ha centrado en praderas de Posidonia oceanica para evaluar su papel como zonas de refugio, función que ha sido poco estudiada. Este trabajo se ha llevado a cabo en la Reserva Marina de Tabarca (España, SW Mar Mediterráneo). Las muestras se recolectaron con redes de plancton fijas en periodos diurnos y nocturnos, y a dos profundidades (13 y 15 m), durante 5 días consecutivos en el mes de Julio de 2000. Se capturaron 353 larvas y 256 fueron identificadas. Los taxones más abundantes fueron S. aurita, Sparidae, Engraulis encrasicolus y Gobiidae. Sparidae dominó al nivel de las hojas de la pradera durante el día, incrementando su presencia en la columna de agua durante la noche; mientras que la S. aurita se encontró a lo largo de toda la columna de agua en los dos periodos estudiados. Nuestro estudio confirma el papel de las praderas de P. oceanica como zona de refugio transitoria para los primeros estadios de larvas de de peces, aunque limitado a algunas especies demersales.