Bayesian model selection for electromagnetic kaon production on the nucleon

We present the results of a Bayesian analysis of a Regge model to describe the background contribution for K+ Lambda and K+ Sigma0 photoproduction. The model is based on the exchange of K+(494) and K*+(892) trajectories in the t-channel. We utilise the Bayesian evidence Z to determine the best model variant for each channel. The Bayesian evidence integrals were calculated using the Nested Sampling algorithm. For different prior widths, we find decisive Bayesian evidence (\Delta ln Z ~ 24) for a K+ Lambda photoproduction Regge model with a positive vector coupling and a negative tensor coupling constant for the K*+(892) trajectory, and a rotating phase factor for both trajectories. Using the chi^2 minimisation method, one could not draw this conclusion from the same dataset. For the K+ Sigma0 photoproduction Regge model, on the other hand, the difference between the evidence integrals is insufficient to pinpoint one model variant.Comment: 13 pages, 4 figure

Produção de carne bovina utilizando confinamento.

Confinamento; Ganho de peso e eficiência de conversão alimentar; Característica de carcaça

Interpretação dos resultados de análises bromatológicas de silagens e outros ingredientes para ração.

O planejamento da alimentação de bovino com forragens conservadas, tais como silagens, envolve informações sobre a disponibilidade deste volumoso e sua qualidade. O controle da qualidade, por meio de análises químico-bromatológicas do produto em laboratório especializado, e essencial, devido as dificuldades para monitorar a fermentação no silo, a semelhança de uma indústria, que esteriliza ou pasteuriza a matéria-prima antes de adicionar os inoculantes, e controlar a temperatura para obter um produto padronizado. O uso de resíduos de cultura, incluindo-se os resíduos de pré-limpeza, e de indústria, como volumosos para alimentação de bovinos também requer análise criteriosa de qualidade, em razão da enorme variabilidade encontrada (produto não-padronizado) nestes produtos.Resumo expandido

Study of the spatial variation of the biodegradation rate of the herbicide bentazone with soil depth using contrasting incubation methods

Vertical and horizontal spatial variability in the biodegradation of the herbicide bentazone was compared in sandy-loam soil from an agricultural field using sieved soil and intact soil cores. An initial experiment compared degradation at five depths between 0 and 80 cm using sieved soil. Degradation was shown to follow the first-order kinetics, and time to 50% degradation (DT50), declined progressively with soil depth from 56 d at 0–10 cm to 520 d at 70–80 cm. DT50 was significantly correlated with organic matter, pH and dehydrogenase activity. In a subsequent experiment, degradation rate was compared after 127 d in sieved soil and intact cores from 0 to 10 and 50 to 60 cm depth from 10 locations across a 160 × 90 m portion of the field. Method of incubation significantly affected mean dissipation rate, although there were relatively small differences in the amount of pesticide remaining in intact cores and sieved soil, accounting for between 4.6% and 10.6% of that added. Spatial variability in degradation rate was higher in soil from 0 to 10 cm depth relative to that from 50 and 60 cm depth in both sieved soil and intact core assessments. Patterns of spatial variability measured using cores and sieved soil were similar at 50–60 cm, but not at 0–10 cm depth. This could reflect loss of environmental context following processing of sieved soil. In particular, moisture content, which was controlled in sieved soil, was found to be variable in cores, and was significantly correlated with degradation rate in intact topsoil cores from 0 to 10 cm depth

Testing models with non-minimal Higgs sector through the decay t->q+WZ

We study the contribution of charged Higgs boson to the rare decay of the top quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and triplets. Higgs doublets are needed to couple charged Higgs with quarks, whereas the Higgs triplets are required to generate the non-standard vertex HWZ at tree-level. It is found that within a model that respect the custodial SU(2) symmetry and avoids flavour changing neutral currents by imposing discrete symmetries, the decay mode t->b+WZ, can reach a branching ratio of order 0.0178, whereas the decay modes t->(d,s)+WZ, can reach a similar branching ratio in models where flavour changing neutral currents are suppressed by flavour symmetries.Comment: Typeset using REVTEX and EPSF, 5 pag, 2 figure

Planar laser induced fluorescence for temperature measurement of optical thermocavitation

Pulsed laser-induced cavitation, has been the subject of many studies describing bubble growth, collapse and ensuing shock waves. To a lesser extent, hydrodynamics of continuous wave (CW) cavitation or thermocavitation have also been reported. However, the temperature field around these bubbles has not been measured, partly because a sensor placed in the fluid would interfere with the bubble dynamics, but also because the short-lived bubble lifetimes (∼70–200 µs) demand high sampling rates which are costly to achieve via infrared (IR) imaging. Planar laser-induced fluorescence (PLIF) provides a non-intrusive alternative technique to costly IR imaging to measure the temperature around laser-induced cavitation bubbles. A 440 nm laser sheet excites rhodamine-B dye to fluoresce while thermocavitation is induced by a CW 810 nm laser. Post-calibration, the fluorescence intensity captured with a high-speed Phantom Miro camera is correlated to temperature field adjacent to the bubble. Using shadowgraphy and PLIF, a significant decrease in sensible heat is observed in the nucleation site– temperature decreases after bubble collapse and the initial heated volume of liquid shrinks. Based on irradiation time and temperature, the provided optical energy is estimated to be converted up to 50% into acoustic energy based on the bubble's size, with larger bubbles converting larger percentages

Free Fields for Chiral 2D Dilaton Gravity

We give an explicit canonical transformation which transforms a generic chiral 2D dilaton gravity model into a free field theory.Comment: LaTeX file, 4 pages, to appear in Phys. Rev.

Anxiolytic effect of Mozart music over short and long photoperiods as part of environmental enrichment in captive Rattus norvegicus (Rodentia: Muridae)

Music is known to be able to elicit emotional changes, including anxiolytic effects on humans and animals. Photoperiod has also been reported to play an important role in the modulation of anxiety. In the present study, we examined whether the effect of music on anxiety is influenced by day length, comparing, short day (SD; 8:16 h light/dark) and long day (LD; 16:8 h light/dark) with controls (CD; 12:12 h light/dark). After 8 weeks of photoperiod treatment, rats were randomly assigned to 2 groups: silence and music. In the music group, rats were exposed to music 24 h before behavioral tests to quantify anxiety level. Exposure to Mozart music reduced anxiety in rats in the CD group. These effects of music were abolished by LD. Independently of music, rats exposed to SD exhibited higher levels of anxiety-like behavior than rats exposed to CD, in elevated plus-maze and open-field tests. The present findings suggest that the anxiolytic effects of Mozart music are photoperiod-dependent