Calorons and BPS monopoles with non-trivial holonomy in the confinement phase of SU(2) gluodynamics

With the help of the cooling method applied to SU(2) lattice gauge theory at non-zero $T \le T_c$ we present numerical evidence for the existence of superpositions of Kraan-van Baal caloron (or BPS monopole pair) solutions with non-trivial holonomy, which might constitute an important contribution to the semi-classical approximation of the partition function.Comment: 3 pages, 6 figures, contribution to Lattice2002(topology

The Schr\"odinger Functional for Improved Gluon and Quark Actions

The Schr\"odinger Functional (quantum/lattice field theory with Dirichlet boundary conditions) is a powerful tool in the non-perturbative improvement and for the study of other aspects of lattice QCD. Here we adapt it to improved gluon and quark actions, on isotropic as well as anisotropic lattices. Specifically, we describe the structure of the boundary layers, obtain the exact form of the classically improved gauge action, and outline the modifications necessary on the quantum level. The projector structure of Wilson-type quark actions determines which field components can be specified at the boundaries. We derive the form of O(a) improved quark actions and describe how the coefficients can be tuned non-perturbatively. There is one coefficient to be tuned for an isotropic lattice, three in the anisotropic case. Our ultimate aim is the construction of actions that allow accurate simulations of all aspects of QCD on coarse lattices.Comment: 39 pages, LaTeX, 11 embedded eps file

Use of stomach tubing as an alternative to rumen cannulation to study ruminal fermentation and microbiota in sheep and goats

10 páginas, 4 tablas, 1 figura.Rumen cannulation is the reference method for collection of representative samples of rumen digesta. However, it is not always viable, which obliges to depend on less invasive techniques, such as stomach tubing. The aim of this work was to study if the differences in fermentation parameters and rumen microbial populations observed between species (sheep and goats), diets (forage and forage plus concentrate) and sampling times (pre- and post-feeding) are consistent when collecting the samples through stomach tube or rumen cannula, in an attempt to validate the use of the former as an alternative to the latter. Four sheep and four goats, fitted with ruminal cannula, were fed either forage (F diet; alfalfa hay) or forage plus concentrate (1:1; FC diet), in two 15-day periods. At the end of each period (days 14 and 15), samples of rumen digesta were taken by stomach tube and rumen cannula, before and 4. h after morning feeding, for determination of ruminal fermentation parameters (pH, and lactate, ammonia and total VFA concentrations). The three main rumen microbial groups (bacteria, protozoa and methanogenic archaea) and two fibrolytic bacteria ( Ruminococcus flavefaciens and Fibrobacter succinogenes) were quantified by real-time PCR and, additionally, PCR-DGGE analysis of the bacterial community on the rumen digesta samples collected post-feeding was carried out. Overall, sampling through ruminal cannula and stomach tube gave similar results regarding fermentation parameters when comparing species, diets and sampling times. Despite samples for microbiology assays contained liquid plus solid fractions when collected through rumen cannula and mostly liquid when collected through stomach tube, both techniques showed certain consistency in the effects of treatments on the rumen microbiota ( e.g., both revealed no differences between species in total bacteria, archaea and R. flavefaciens concentrations, and higher protozoa numbers in goats than in sheep). However, there was also some discrepancy regarding microorganism concentrations, particularly concerning sampling times ( e.g., differences between pre- and post-feeding samplings were only observed in rumen cannula samples for total bacteria and methanogenic archaea, and in stomach tube samples for R. flavefaciens concentrations). Therefore, this study supports that non-invasive stomach tubing is a feasible alternative to surgical rumen cannulation in sheep and goats to examine ruminal fermentation. Nonetheless, caution should be taken when using this technique to assess the structure and composition of the rumen microbial community.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO; AGL2011-27218 and AGL2011-23700). E. Ramos-Morales acknowledge the receipt of a research contract from the Spanish National Research Council (CSIC), Junta de Ampliación de Estudios (JAEdoc) Programme.Peer reviewe

Evaluación en campo de formulaciones de Bacillus thuringiensis contra Diatraea sp.

La aplicacio?n de Bacillus thuringiensis para el control de barrenadores de la can?a de azu?car es una buena alternativa dentro del control biolo?gico. Formulaciones granulares y asperjables se aplicaron a cultivos de can?a infestados naturalmente con Diatraea, en Ameca, Jal., Los formulados no fueron fitoto?xicos al cultivo. Los asperjables fueron los ma?s efectivos en las dosis de 7 y 10%, y son tan eficientes como un formulado comercial y altamente competitivos. Las parcelas con granulares tuvieron los niveles de dan?o ma?s altos, superando incluso al testigo, por lo que no se recomienda su uso en cultivos de can?a de azu?car

Unemployment Exits Before and During the Crisis

Using administrative data from Spain, we compare the pattern and the determinants of individual unemployment durations and the stability of jobs found after unemployment before and during the recent crisis. We find particularly strong effects of the crisis on the hazards in the beginning of the unemployment spell. The groups hit hardest by the crisis are men, immigrants, older workers, and low-educated individuals. The disadvantage of men is mainly due to the more pro-cyclical nature of men's jobs. The increase in average unemployment duration and the fall in the duration of new jobs are not explained by composition effects