Abstract. This study aimed to establish P4 and luteinizing hormone (LH) levels and ovarian activity as approaches to monitor the cyclicity of ewes under postpartum anestrus after the male effect approach. Santa Inês females (n = 66) were evenly distributed into experimental groups where they were brought into contact with an intact male during the postpartum period of 35 to 40 days (T1) and 55 and 60 days postpartum (T2). Ewes were isolated from males for 30 days before the onset of the experiment. Estrus events were detected in 93.30% (T1) and 100 % (T2) of females. Mean P4 concentrations (η g mL −1 ) before and after mating were 0.53 ± 0.17 and 4.55 ± 0.24 (T1) and 0.73 ± 0.06 and 4.90 ± 0.11 (T2), respectively, and concentrations were found to be lower (P < 0.05) before contact between genders. Preovulatory peaks of LH (η g mL −1 ) were evaluated at 42 (T2) and at 80 h (T1) after exposure to males, with mean ovulatory follicles of 7.90 ± 0.31 (T1) and 8.50 ± 0.30 mm (T2) and a mean number of ovulations of 1.50 ± 0.54 (T1) and 1.60 ± 0.51 (T2). Pregnancy rates were 85.70 % (T1) and 93.3 % (T2), with no difference (P > 0.05) between groups. Results showed that the male effect was effective for inducing and concentrating the occurrence of estrus in postpartum ewes that had lambed within 35 to 60 days previously. Moreover, preovulatory LH peaks occurred within 80 h after physical contact between genders, which led to follicle luteinization and increased P4 concentration, without compromising pregnancy rates. The male effect can be used with postpartum ewes that had lambed within 35 to 40 days previously in order to decrease time between deliveries.
The aim of this study was to evaluate the pregnancy rate of in vitro produced embryos of Gyr cattle (Bos indicus) after cryopreservation by the vitrification method under field conditions. Blastocysts in different developmental stages were transferred to recipient cows either fresh (n = 140) or warmed after vitrification (n = 138). The pregnancy rates obtained for fresh embryos were 46.15% (initial blastocyst), 46.93% (blastocyst) and 50.0% (expanded blastocyst) at 35 days postfertilization, and 43.58% (initial blastocyst), 46.93% (blastocyst) and 50.0% (expanded blastocyst) at 60 days. The pregnancy rates after embryo vitrification were 35.0% (initial blastocyst), 42.30% (blastocyst) and 43.47% (expanded blastocyst) at 35 days post-fertilization, and 32.50% (initial blastocyst), 38.46% (blastocyst) and 43.47% (expanded blastocyst) at 60 days. Embryo vitrification or blastocyst developmental stage did not affect pregnancy rates or incidence of embryonic death.In conclusion, vitrification of Gyr (Bos indicus) embryos under field conditions is an efficient method that can be implemented to use surplus in vitro produced embryos without affecting pregnancy rates.Keywords: Bos indicus, cryobiology, cryotolerance, Zebu. VIABILIDADE DE EMBRIÕES GIR (Bos indicus) PRODUZIDOS In vitro APÓS CRIOPRESERVAÇÃO EM CONDIÇÕES DE CAMPO PELA VITRIFICAÇÃORESUMO: Objetivou-se com o trabalho avaliar a taxa de prenhez a partir de embriões de bovinos da raça Gir (Bos indicus) produzidos in vitro após criopreservação em condições de campo pelo método de vitrificação. Blastocistos em diferentes estádios de desenvolvimento foram transferidos a fresco (n = 140) ou aquecidos após a vitrificação (n = 138). As taxas de prenhez de embriões frescos foram 46,15% (blastocisto inicial), 46,93% (blastocisto) e 50,00% (blastocisto expandido) aos 35 dias e 43,58% (blastocisto inicial), 46,93% (blastocisto) e 50,00% (blastocisto expandido) aos 60 dias pós-fertilização, respectivamente. As taxas de prenhez após a vitrificação foram 35,00% (blastocisto inicial), 42,30% (blastocisto) e 43,47% (blastocisto expandido) aos 35 dias e 32,50% (blastocisto inicial), 38,46% (blastocisto) e 43,47% (blastocisto expandido) aos 60 dias pós-fertilização, respectivamente. A vitrificação do embrião ou estádio do desenvolvimento não afetaram as taxas de prenhez ou incidência de morte embrionária. Em conclusão, a vitrificação de embriões de bovinos da raça Gir (Bos indicus) sob condições de campo é um método eficiente que pode ser implementado para aproveitar os embriões produzidos in vitro excedentes sem afetar a taxa de prenhez.
<p>This paper presents the numerical and variational solutions of the 1D Schrödinger Equation submitted to the Pöschl-Teller potential. The methods used were the Variational Method and the Finite Difference Method. They were presented in a didactic and detailed way with the purpose of instructing both undergraduate and graduate students, about the applicability and effectiveness of the aforementioned methods. We use the Pöschl-Teller potential due to the fact that it is little explored in the books of Quantum Mechanics used in undergraduation courses and also because of its diverse applications, such as in Bose-Einstein condensates, waveguides, topological defects in field theory and so on. We conclude this paper comparing the variational and numerical solutions with the analytical solution and present the advantages of each method.</p>
We present for the first time an approach about Bose–Einstein condensates made up of atoms with attractive interatomic interactions confined to the Pöschl–Teller hyperbolic potential. In this paper, we consider a Bose–Einstein condensate confined in a cigar-shaped, and it was modeled by the mean field equation known as the Gross–Pitaevskii equation. An analytical (variational method) and numerical (two-step Crank–Nicolson) approach is proposed to study the proposed model of interatomic interaction. The solutions of the one-dimensional Gross–Pitaevskii equation obtained in this paper confirmed, from a theoretical point of view, the possibility of the Pöschl–Teller potential to confine Bose–Einstein condensates. The chemical potential as a function of the depth of the Pöschl–Teller potential showed a behavior very similar to the cases of Bose–Einstein condensates and superfluid Fermi gases in optical lattices and optical superlattices. The results presented in this paper can open the way for several applications in atomic and molecular physics, solid state physics, condensed matter physics, and material sciences.
In this paper, we theoretically investigate the dynamics and stability of matter‐wave solitons (MWS) in a cigar‐shaped Bose–Einstein condensate (BEC) consisting of atoms with attractive interatomic interactions trapped by Pöschl–Teller (PT) potential. In this scenario, we propose the idea of the BEC being dragged by PT potential at a constant speed. The BEC was modeled by the quasi‐one‐dimensional Gross–Piteaevskii Equation (1D‐GPE). In addition, an analytical (time‐dependent variational method) and numerical (split‐step Crank–Nicolson method) approach has been proposed to investigate the dynamic properties of solitons during the temporal evolution of this system. Both analytical and numerical results demonstrated that MWSs dragged by PT potential can be stable. From a general point of view, the results obtained in this paper can motivate both theoretical and experimental investigations on the dynamics and stability of solitons in dilute and ultracold unitary Bose gases trapped by PT potential, nonlinear optical properties in PT quantum wells, and propagation of solitons in nonlinear media.
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