Convection-induced nonlinear-symmetry-breaking in wave mixing

We show that the combined action of diffraction and convection (walk-off) in wave mixing processes leads to a nonlinear-symmetry-breaking in the generated traveling waves. The dynamics near to threshold is reduced to a Ginzburg-Landau model, showing an original dependence of the nonlinear self-coupling term on the convection. Analytical expressions of the intensity and the velocity of traveling waves emphasize the utmost importance of convection in this phenomenon. These predictions are in excellent agreement with the numerical solutions of the full dynamical model.Comment: 5 page

Spatial fluctuations in an optical parametric oscillator below threshold with an intracavity photonic crystal

We show how to control spatial quantum correlations in a multimode degenerate optical parametric oscillator type I below threshold by introducing a spatially inhomogeneous medium, such as a photonic crystal, in the plane perpendicular to light propagation. We obtain the analytical expressions for all the correlations in terms of the relevant parameters of the problem and study the number of photons, entanglement, squeezing, and twin beams. Considering different regimes and configurations we show the possibility to tune the instability thresholds as well as the quantumness of correlations by breaking the translational invariance of the system through a photonic crystal modulation.Comment: 12 pages, 7 figure

Induction of synchronized estrus in dairy goats with different gonadotrophins.

The objective of this study was to evaluate lhe efficiency of two gonadotrophins in induction of estrus in dairy goats. A total of 47 dairy goats were randomly divided according to breed into two treatments (T1 and T2). In both treatments, goats received intravaginal sponges containing 60 mg medroxy-progesterone acetate for six days and sub- vulvar administration of 22.5 mg of d-cloprostenol at the time of sponge insertion. In TI (n=23) and T2 (n=24), animaIs received intramuscuIar administration of 200 lU and 250 lU of eCG and hCG, respectively. After sponge removal, goats were monitored twice daily (06:00 a.m. and 18:00 p.m.) with bucks. Animals were bred at lhe start of estrus and at each 12 hours interval until lhe end of estrus. Pregnancy was checked by ultrasonography 63 days after breeding. Percentage of animals in estrus did not differ (P>0.05) between TI (95.6%) and T2 (78.3%). There was no effect (P>0.05) of treatment on interval from sponge removal to lhe Start of estrus (IE) and duration of estrus (DE). The" average IE was 48.0 + 9.4h and 46.2+ 8.4h for eCG and hCG, respectively. The average DE was 20.7 + 11.9h and 18.8 + 9.0h for eCG and hCG, respectively. Pregnancy cate did not differ (P>0.05) between eCG (77.3%) and hCG (61.1%). Results of this study showed that estrus can be efficiently induced in female goats outside lhe breeding season with both eCG and hCG

Superovulation in does based on first follicular wave of the estrous cycle.

Edição dos resumos da 20ª Reunião Anual da Sociedade Brasileira de Tecnologia de Embriões, Araxá, 2006

Superovulação de cabras utilizando a primeira onda folicular do ciclo estral.

Edição dos resumos da 20. Reunião Anual da Sociedade Brasileira de Tecnologia de Embriões, Araxá, MG, agosto 2006

Measuring the Complete Transverse Spatial Mode Spectrum of a Wave Field

We put forward a method that allows the experimental determination of the entire spatial mode spectrum of any arbitrary monochromatic wave field in a plane normal to its propagation direction. For coherent optical fields, our spatial spectrum analyzer can be implemented with a small number of benchmark refractive elements embedded in a single Mach-Zehnder interferometer. We detail an efficient setup for measuring in the Hermite-Gaussian mode basis. Our scheme should also be feasible in the context of atom optics for analyzing the spatial profiles of macroscopic matter waves

An absolute quantum energy inequality for the Dirac field in curved spacetime

Quantum Weak Energy Inequalities (QWEIs) are results which limit the extent to which the smeared renormalised energy density of a quantum field can be negative. On globally hyperbolic spacetimes the massive quantum Dirac field is known to obey a QWEI in terms of a reference state chosen arbitrarily from the class of Hadamard states; however, there exist spacetimes of interest on which state-dependent bounds cannot be evaluated. In this paper we prove the first QWEI for the massive quantum Dirac field on four dimensional globally hyperbolic spacetime in which the bound depends only on the local geometry; such a QWEI is known as an absolute QWEI