A monopole solution from noncommutative multi-instantons

We extend the relation between instanton and monopole solutions of the selfduality equations in SU(2) gauge theory to noncommutative space-times. Using this approach and starting from a noncommutative multi-instanton solution we construct a U(2) monopole configuration which lives in 3 dimensional ordinary space. This configuration resembles the Wu-Yang monopole and satisfies the selfduality (Bogomol'nyi) equations for a U(2) Yang-Mills-Higgs system.Comment: 19 pages; title and abstract changed, brane interpretation corrected. Version to appear in JHE

Single gap superconductivity in beta-Bi2Pd

beta-Bi2Pd compound has been proposed as another example of a multi-gap superconductor [Y. Imai et al., J. Phys. Soc. Jap. 81, 113708 (2012)]. Here, we report on measurements of several important physical quantities capable to show a presence of multiple energy gaps on our superconducting single crystals of beta-Bi2Pd with the critical temperature Tc close to 5 K. The calorimetric study via a sensitive ac technique shows a sharp anomaly at the superconducting transition, however only a single energy gap is detected. Also other characteristics inferred from calorimetric measurements as the field dependence of the Sommerfeld coefficient and the temperature and angular dependence of the upper critical magnetic field point unequivocally to standard single s-wave gap superconductivity. The Hall-probe magnetometry provides the same result from the analysis of the temperature dependence of the lower critical field. A single-gapped BCS density of states is detected by the scanning tunneling spectroscopy measurements. Then, the bulk as well as the surface sensitive probes evidence a standard conventional superconductivity in this system where the topologically protected surface states have been recently detected by ARPES [M. Sakano et al., Nature Comm. 6, 8595 (2015)] .Comment: 7 pages, 4 figures, 1 tabl

Avaliação da contaminação de aquífero furnas por pesticidas.

Resumo

High-magnetic field lattice length changes in URu2Si2

We report high magnetic field (up to 45 T) c-axis thermal expansion and magnetostriction experiments on URu2Si2 single crystals. The sample length change associated with the transition to the hidden order phase becomes increasingly discontinous as the magnetic field is raised above 25 T. The re-entrant ordered phase III is clearly observed in both the thermal expansion and magnetostriction above 36 T, in good agreement with previous results. The sample length is also discontinuous at the boundaries of this phase, mainly at the upper boundary. A change in the sign of the coefficient of thermal-expansion is observed at the metamagnetic transition (B_M = 38 T) which is likely related to the existence of a quantum critical end point.Comment: 5 pages, 4 figures, to be published in PR

The effect of a single, early-life administration of a probiotic on piglet growth performance and faecal microbiota until weaning

The establishment and maintenance of a balanced gut microbiota in early life play a pivotal role in pigs. This study aims to evaluate the effect of the administration of a single early-life probiotic on piglet faecal microbiota and growth performance until weaning. Forty-eight hours after birth (d0), 820 piglets were allocated into 4 groups (205 piglets/16 litters/group) and orally inoculated as follows: 1) Control (CO: 4 mL of pure water); 2) Saccharomyces (SA: 4 mL containing a total of 1 × 1010 CFU of Saccharomyces cerevisiae var. boulardii CNCM-1079; 3) Enterococcus (EF: 4 mL containing a total of 1 × 1010 CFU of Enterococcus faecium lactiferm WS200); 4) a mix of the two probiotics at the same doses (SAEF). At d7 and d18, the piglets were weighed, and faeces from the piglets (18 piglets/group from 6 sows/group) and their mothers were analysed for a microbial profile by sequencing the v3-v4 regions of the 16S rRNA gene. Data were arranged in a 2x2 factorial design. The probiotic supplement improved piglet ADG in the periods d7-d18 (p <.0001) and d0-d18 (p <.05). From d7 to d18, the SA group tended to have lower mortality than the CO group (p =.08). The probiotic supplement significantly affected the microbial beta diversity at d7 (p <.05). The SA probiotic favoured the colonisation of Erysipelatoclostridium and Christensenella, and the EF probiotic the colonisation of Lachnospiraceae. These results highlighted that the administration of a single early-life probiotic supplement could improve piglet performance and shape the faecal microbial profile.Highlights A single dose of E. faecium or S. cerevisiae improved piglet performance in the pre-weaning period. The early administration of probiotics shaped the faecal microbial profile of the piglets and contributed to improved growth performance

AN EXPERIMENTAL STUDY OF THE CONVECTIVE HEAT TRANSFER ENHANCEMENT: APPLICATION OF TURBULENCE PROMOTERS

This work presents an experimental study addressing the effects of turbulence promoters on heat transfer rate at circular cylinder in external cross flow. Within this framework, the work focuses on assessing the effects of three kind of turbulence promoters (with circular, square and hexagonal cross sections) on convective heat transfer enhancement. The distance from turbulence promoters to the circular cylinder (50, 100 and 150mm upstream), as well as the free stream velocity inside the wind tunnel (Reynolds number) were the parameters investigated. The validation of the experimental methodology was performed by comparing the present results with empiric correlations available in the literature. The main results indicate that the convective heat transfer coefficient was enhanced when using turbulence promoters. The highest heat transfer enhancement obtained was around 25% correponding to the case of square turbulence promoter placed closely (50mm) to the circular cylinder. Finally, it is worth mentioning that all the experimental results for the convective coefficient were condensed in a new empirical correlation with good accuracy