A comparative study of the dynamic critical behavior of the four-state Potts like models

We investigate the short-time critical dynamics of the Baxter-Wu (BW) and $n=3$ Turban (3TU) models to estimate their global persistence exponent $\theta _{g}$. We conclude that this new dynamical exponent can be useful in detecting differences between the critical behavior of these models which are very difficult to obtain in usual simulations. In addition, we estimate again the dynamical exponents of the four-state Potts (FSP) model in order to compare them with results previously obtained for the BW and 3TU models and to decide between two sets of estimates presented in the current literature. We also revisit the short-time dynamics of the 3TU model in order to check if, as already found for the FSP model, the anomalous dimension of the initial magnetization $x_{0}$ could be equal to zero

Test of Local Scale Invariance from the direct measurement of the response function in the Ising model quenched to and to below TCT_C

In order to check on a recent suggestion that local scale invariance [M.Henkel et al. Phys.Rev.Lett. {\bf 87}, 265701 (2001)] might hold when the dynamics is of Gaussian nature, we have carried out the measurement of the response function in the kinetic Ising model with Glauber dynamics quenched to $T_C$ in $d=4$, where Gaussian behavior is expected to apply, and in the two other cases of the $d=2$ model quenched to $T_C$ and to below $T_C$, where instead deviations from Gaussian behavior are expected to appear. We find that in the $d=4$ case there is an excellent agreement between the numerical data, the local scale invariance prediction and the analytical Gaussian approximation. No logarithmic corrections are numerically detected. Conversely, in the $d=2$ cases, both in the quench to $T_C$ and to below $T_C$, sizable deviations of the local scale invariance behavior from the numerical data are observed. These results do support the idea that local scale invariance might miss to capture the non Gaussian features of the dynamics. The considerable precision needed for the comparison has been achieved through the use of a fast new algorithm for the measurement of the response function without applying the external field. From these high quality data we obtain $a=0.27 \pm 0.002$ for the scaling exponent of the response function in the $d=2$ Ising model quenched to below $T_C$, in agreement with previous results.Comment: 24 pages, 6 figures. Resubmitted version with improved discussions and figure

An alternative order parameter for the 4-state Potts model

We have investigated the dynamic critical behavior of the two-dimensional 4-state Potts model using an alternative order parameter first used by Vanderzande [J. Phys. A: Math. Gen. \textbf{20}, L549 (1987)] in the study of the Z(5) model. We have estimated the global persistence exponent $\theta_g$ by following the time evolution of the probability $P(t)$ that the considered order parameter does not change its sign up to time $t$. We have also obtained the critical exponents $\theta$, $z$, $\nu$, and $\beta$ using this alternative definition of the order parameter and our results are in complete agreement with available values found in literature.Comment: 6 pages, 6 figure

Effect of hCG administration on accessory corpus luteum formation and area in estrous induced nulliparous Santa Inês ewes.

Proceedings V International Symposium on Animal Biology of Reproduction, October 8-11, 2014, Campinas, SP

Absorbing Phase Transition in a Four State Predator Prey Model in One Dimension

The model of competition between densities of two different species, called predator and prey, is studied on a one dimensional periodic lattice, where each site can be in one of the four states say, empty, or occupied by a single predator, or occupied by a single prey, or by both. Along with the pairwise death of predators and growth of preys, we introduce an interaction where the predators can eat one of the neighboring prey and reproduce a new predator there instantly. The model shows a non-equilibrium phase transition into a unusual absorbing state where predators are absent and the lattice is fully occupied by preys. The critical exponents of the system are found to be different from that of the Directed Percolation universality class and they are robust against addition of explicit diffusion.Comment: 10 pages, 6 figures, to appear in JSTA

COMPARAÇÃO DO COMPORTAMENTO DO DECAIMENTO RADIOATIVO ATRAVÉS DE LANÇAMENTOS DE POLIEDROS

Modern physics is part of the High School physics curriculum, but it is rarely covered. Thus, subjects such as radioactivity and radioactive decay are rarely worked in the classroom, and more difficult with associated practice, since radioactive materials are harmful and follow specific legislation for their use. In order to try to overcome this deficiency and provide a practice, a simulation of the radioactive decay curves was performed using sets of polyhedra (physical or virtual), where each set is formed with polyhedra with a certain number of faces. When an atom emits some type of radiation, it is said that the chemical element has undergone radioactive decay and this process, in addition to being a transmutation of matter, is a spontaneous and completely random process. The average time in which half of the atoms in a given sample decay, forming another chemical element, known as the half-life time, is specific to each radioactive chemical element and polyhedra with different numbers of faces can be used to simulate this condition. The probability of a specific atom decaying after a certain period of time can be simulated by comparing the polyhedrons throwings by subtracting the number of polyhedra as a function of one of the chosen faces.A física moderna faz parte do currículo de física do ensino médio, porém raramente ela é abordada. Dessa maneira, assuntos como radioatividade e decaimento radiativo dificilmente são trabalhados em sala de aula, e mais dificilmente com prática associada visto que materiais radioativos são nocivos e seguem legislação específica para sua manipulação. Para tentar suprir essa deficiência e propiciar uma prática foi realizada uma simulação das curvas de decaimento radioativo utilizando conjuntos de poliedros (físicos ou virtuais), onde cada conjunto é formado com poliedros com um determinado número de faces. Quando um átomo emite algum tipo de radiação é dito que o elemento químico sofreu um decaimento radioativo e este processo, além de ser uma transmutação da matéria, é um processo espontâneo e completamente aleatório. O tempo médio em que metade dos átomos de uma certa amostra decaem, formando outro elemento químico, conhecido como tempo de meia-vida, é específico para cada elemento químico radioativo e pode-se utilizar poliedros com números de faces diferentes para simular esta condição. A probabilidade de um átomo específico decair após um certo período de tempo pode ser simulada comparando o lançamento dos poliedros subtraindo-se a quantidade de poliedros em função de uma das faces escolhidas

Evaluation of superovulatory response in Santa Inês ewes by ultrasonography and laparoscopy.

The development and use of non-invasive techniques would reduce risks of surgery sequels on the same animal and use of the donor could be optimized. The aim of this study was to evaluate the accuracy of ultrasonography performed prior to embryo collection to estimate superovulation response in sheep. Fifteen pluriparous Santa Inês sheep, 2 to 5 year old, with an average body weight of 46.79 ± 6.00 kg and body condition score of 2.96 ± 0.32 (1 to 5 scale) were allocated into 3 groups (GI, GII, GIII) in a cross-over design. In GI, intravaginal sponges (60 mg of medroxyprogesterone acetate; Progespon®, Schering Plough Animal Health, São Paulo, Brazil) were inserted (Day 0) and maintained for 14 days, and the superovulatory (SOV) protocol started on Day 12. In GII and GIII, intravaginal sponges were inserted (Day 0) and maintained for 6 days. On Day 5, the animals were treated with 300 IU of eCG (Novormon 5000®, Schering Plough Animal Health) and 5 mg of dinoprost (Lutalyse® Pfizer Animal Health, São Paulo, Brazil) i.m. Animals in GIII received 0.025 mg of gonadorelin acetate (Gestran-Plus®, Tecnopec, São Paulo, Brazil) i.m. 12 h after sponge withdrawal. In GII and GIII, the SOV protocol started 48 h after sponge removal and a new sponge was inserted immediately after its removal. The SOV protocol in all groups consisted of 200 mg of pFSH (Folltropin-V®, Tecnopec) administered in 6 decreasing doses given every 12 h (50/50, 30/30, and 20/20 mg). At the time of the fifth dose of pFSH, 5 mg of dinoprost was administered i.m. and the sponges were removed. Animals were bred by a sexually mature ram twice a day until the end of estrus. Prior to embryo collection, an ultrasonographic evaluation (5 MHz, Aloka SSD-500, Tokyo, Japan) was performed to determine the number of CL present on both ovaries. The number of CL was further evaluated by laparoscopy, when it was possible to detect poor responders or even non-ovulating animals. Statistical analysis was performed using all tests at the 95% confidence interval by SAEG program. Results are presented as mean ± SE. The number of CL was not different among all groups. The total number (GI, GII, and GIII) of CL determined by ultrasonography (9.09 ± 5.01) was not different (P > 0.05) from that observed by laparoscopy (8.87 ± 5.25). A significant correlation (r = 0.56, P < 0.0005) between evaluation performed by ultrasonography and laparoscopy was observed. These results suggest that ultrasonography can be used to determine the response to the superovulatory protocol. As embryo collection in sheep is performed mainly by surgical techniques, the implementation of non-invasive techniques such as ultrasonography could avoid unnecessary surgeries on animals that did not respond to the SOV protocol, therefore preventing early culling of embryo donors. Top Print this pagePrint Email this page View Issue Contents Abstract Export Citation Tools Print Bookmark Email this page Early Alert Subscribe to our Early Alerts for the latest journal issue contents.Edição dos Proceedings of the Annual Conference of the International Embryo Transfer Society, Córdoba, Argentina, 9?12 January 2010