963 resultados para Projective synchronization


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In this work, the dynamic behavior of self-synchronization and synchronization through mechanical interactions between the nonlinear self-excited oscillating system and two non-ideal sources are examined by numerical simulations. The physical model of the system vibrating consists of a non-linear spring of Duffing type and a nonlinear damping described by Rayleigh's term. This system is additional forced by two unbalanced identical direct current motors with limited power (non-ideal excitations). The present work mathematically implements the parametric excitation described by two periodically changing stiffness of Mathieu type that are switched on/off. Copyright © 2005 by ASME.

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This paper describes the UNESP robotic team in the medical trash collector task, proposed on the 5 rd IEEE Latin American Robots Competition in the LEGO category. We present our understanding of the task and discuss the proposed solution, focusing on the mechanical and computational issues of the robots. The mechanics is based on rigid body capability of transforming rotational into curvilinear movement. With respect to the computational control, the system is modeled as a reactive system with sequential transition of behaviors. A state-machine is proposed to allow this transition, and the synchronization of robotic states is guaranteed by the communication system. The proposed approach has shown itself capable of dealing with the high difficulty degree of this cooperative task. ©2006 IEEE.

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The objective of this study was to evaluate the LH surge after last hormonal injection of synchronization of ovulation protocols in buffalo. Fifteen multiparous buffaloes received 25 mg of Lecirelin in Day 0, and 150 mg of D-Cloprostenol on Day 7. On Day 8, estradiol benzoate was injected in Group 1 (0.5 mg, n = 5) and Group 2 (1.0 mg, n = 5). On Day 9, five buffaloes received 25 mg of Lecirelin (Control). Blood samples were collected for measure the LH concentrations on Day 7 and then every 3 hours until 72 hours after the PGF 2a injection. For evaluation of LH surge were compared the interval between PGF 2a injection to LH surge, duration, amplitude and area under the LH peak. The LH surge occurred 51.0 + 0.0 hours, 47.3 + 2.7 hours and 47.0 + 3.8 hours after PGF 2a injection for Control, Group 1 and Group 2, respectively (P > 0.05). The duration of LH peak in Control (7.8 + 1.5 hours) was shorter than Groups 1 and 2 (10.5 + 1.5 hours vs. 10.8 + 2.4 hours, respectively; P < 0.05). The amplitudes of LH peak were 4.5 + 0.4 ng/mL, 4.0 + 0.4 ng/mL and 4.3 + 0.8 ng/mL for Control, Group 1 and Group 2, respectively (P > 0.05). The area under LH peak for Control (4.8 ± 0.7) was smaller than the areas of the Groups 1 and 2 (8.8 ± 2.5 vs. 8.7 2.2, respectively; P < 0.05). In summary, the estradiol benzoate injection provided higher duration and area of LH peak than GnRH injection in Ovsynch protocol in buffalo.

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An improvement to the quality bidimensional Delaunay mesh generation algorithm, which combines the mesh refinement algorithms strategy of Ruppert and Shewchuk is proposed in this research. The developed technique uses diametral lenses criterion, introduced by L. P. Chew, with the purpose of eliminating the extremely obtuse triangles in the boundary mesh. This method splits the boundary segment and obtains an initial prerefinement, and thus reducing the number of necessary iterations to generate a high quality sequential triangulation. Moreover, it decreases the intensity of the communication and synchronization between subdomains in parallel mesh refinement. © 2008 IEEE.

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Considering that there is limited information about the preovulatory LH surge in Zebu cattle (Bos indicus), the purpose of the present work was to assess the LH surge in Nelore cows during the estrous cycle and after ovarian superestimulation of ovarian follicular development with FSH. This information is particularly important to improve superovulatory protocols associated with fixed-time artificial insemination. Nelore cows (n = 12) had their estrus synchronized with an intravaginal device containing progesterone (CIDR-B ®) associated with estradiol benzoate administration (EB, 2.5 mg, i.m., Day 0). Eight days later all animals were treated with PGF2α (Day 8) in the morning (8:00 h) and at night, when CIDR devices were removed (20:00 h). Starting 38 h after the first PGF2α injection, blood sampling and ovarian ultrasonography took place every 4 h, during 37 consecutive hours. Frequent handling may have resulted in a stress-induced suppression of LH secretion resulting in only 3 of 12 cows having ovulations at 46.7 ± 4.9 and 72.3 ± 3.8 h, respectively, after removal of CIDR-B. Thirty days later, the same animals received the described hormonal treatment associated with FSH (Folltropin ®, total dose = 200 mg) administered twice a day, during 4 consecutive days, starting on Day 5. Thirty-six hours after the first injection of PGF2α, to minimize stress, only seven blood samples were collected at 4 h interval each, and ultrasonography was performed every 12 h until ovulation. In 11 of 12 cows (92%) the LH surge and ovulation were observed 34.6 ± 1.6 and 59.5 ± 1.9 h, respectively, after removal of progesterone source. The maximum values for LH in those animals were 19.0 ± 2.6 ng/ml (mean ± S.E.M.). It is concluded that, in Nelore cows submitted to a ovarian superstimulation protocol, the LH surge occurs approximately 35 h after removal of intravaginal device containing progesterone, and approximately 12 h before the LH surge observed after an induced estrus without ovarian superstimulation. © 2008 Elsevier B.V. All rights reserved.

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Twenty six Santa Inês ewes were asigned to three treatments to evaluate the efficiency of the Ovsynch protocol. In the treatment 1 - control (n=8), the estrus was synchronized with sponges containing 60 mg MAP for 14 days. On D14, 300 IU eCG were administered. In treatment 2 (n=9) the Ovsynch protocol was used: 25 μg of GnRH (D0), 37.5 μg of PGF2α (D7) and 25 μg of GnRH (D9). In treatment 3 (n=9) the modified Ovsynch protocol was used: the administration of PGF2α and second GnRH as two days early. Estrus detection was accomplished using teaser. All ewes were mated twice with 12 hours of interval. Pregnancy rate (PR) was evaluated by ultrasonography 30 days after the end of mating. Estrus response was of 88.46% on average, and without differences among treatments (p>0.05). The interval for onset of estrus was greater (p<0.05) in T1, when compared with T2 and T3 (41.31±7.2, 13.37±8.42 and 6.75±5.2 h, respectively). The time of receptivity was greater (p<0.05) in females of T1 and T3 (40.5±6.49 h and 53.68±10.27 h, respectively), compared to females of T2 (34.56±7.2 h). The duration of the induced estrus did not differ significant among treatments (p>0.05). Pregnancy rate was significantly greater (p<0.05) in ewes synchronized with Ovsynch protocol (37.5%, 62.5% and 25% for treatment 1, 2 and 3, respectively). The results show superior efficiency of the Ovsynch protocol, under the experimental conditions.

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This study was carried out with the objective of examining the effect of the short-term estrus synchronization protocol. Ewes were divided in four groups: Control Group (MAP sponges for 12 days, and eCG at withdrawal); Groups I, II and III used the sponge for four days, and 100 μg of PGF was applied at withdrawal; and additionally, Group I (0.1 mg of Estradiol benzoate - EB, in the sponge placement, and in the withdrawn 400 UI of eCG and 50 μg of GnRH 48h later); Group II (35 mg of injectable progesterone and 0.1 mg of EB in the sponge placement, and 400 UI of eCG at withdrawal, and 50 μg of GnRH 48h after); Group III (35 mg of injectable progesterone and 0.2 mg of EB in the sponge placement, and 400 UI of eCG at withdrawal, and 50 ?g of GnRH 56h after). Exams were accomplished for ultrasound and determine the plasmatic concentrations of progesterone and observations of the beginning the estrus and the ovulation. The lack of eCG in Group I caused this protocol to be less efficacious in induction and synchronization of estrus and ovulation. The Control Group had a greater synchronization of estrus and ovulation.

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The resolution and the linearity of time measurements made with the CMS electromagnetic calorimeter are studied with samples of data from test beam electrons, cosmic rays, and beam-produced muons. The resulting time resolution measured by lead tungstate crystals is better than 100 ps for energy deposits larger than 10 GeV. Crystal-to-crystal synchronization with a precision of 500 ps is performed using muons produced with the first LHC beams in 2008. © 2010 IOP Publishing Ltd and SISSA.

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The TV is a potential midia of communication that affects all social classes and it is available in 98% of Brazilian homes. It has been used as a distributor of educational materials since the 1950s. By 2016 the Open Digital TV (ODTV) in Brazil might cover the entire national territory, replacing the TV with analog signals. Concerns about accessibility for People with Special Needs (PSN) in that media have become more intense since the 1990s worldwide. In Brazil, it is estimated 24.6 million of PSN, 23% of them having some type of hearing loss. Of these, 2.9% are reported as deafs. Brazilian Sign Language (LIBRAS) is considered the first literacy language for deaf people in Brazil. In this context, this paper presents a proposal to facilitate the generation of educational content for ODTV based on two components. One is called SynchrLIBRAS and allows subtitles synchronization in Portuguese and a LIBRAS translator window of videos downloaded from the Web. The second component allows the visualization of this content through the Brazilian System of Digital TV and IPTV - environments that implement the middleware Ginga-NCL. The main focus of this paper is the presentation of the first component: SynchrLIBRAS. This proposal has educational purposes, contributing to teach LIBRAS to people who may collaborate with social inclusion of the deaf people.

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This paper proposes a solution to improve the performance of the first order Early Error Sensing (EES) Adaptive Time Delay Tanlock Loops (ATDTL) presented in (Al-Zaabi, Al-Qutayri e Al-Araji, 2005), regarding to frequency estimation and tracking time. The EES-ATDTL are phaselocked-loops (PLL) used to hardware implementations, due to their simple structure. Fixed-points theorems are used to determine conditions for rapid convergence of the estimation process and a estimative of the frecuency input is obtained with a Gaussian filter that improves the gain adaptation. The mathematical models are the presented by (Al-Araji, Al-Qutayri e Al-Zaabi, 2006). Simulations have been performed to evaluate the theoretical results.

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This study aimed to evaluate crambe seeds germination and vigor under water stress conditions induced by polyethylene glycol solutions. The seeds were germinated on substrate moistened with polyethylene glycol solutions, using the osmotic potentials of 0 (control), -0.2, -0.4, -0.6, -0.8, -1.0, -1.2 and -1.4 MPa. The seeds germination was evaluated by normal seedlings and root emission percentages. Vigor was evaluated by germination average time, relative frequency, velocity and synchronization index. It was observed that more negative osmotic potential caused significant reduction in crambe seed germination and vigor, and no normal seedlings was observed at potentials below -0.6 MPa.

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Background: Throughout dairy cows evolution, milk production was always the key point to select the superior animal. Currently, several evidences has shown that high milk production have intensively contributed to the decline of dairy cattle fertility. Beyond milk production, dairy cows have their reproductive performance impaired by another factors, heat stress and repeat-breeding. Methods like fixed time artificial insemination and embryo transfer were developed to minimize the effects of these factors, and improve dairy herds profitability. This review aims to show some key-point experiments conducted to improve the efficiency of the self-appointed protocols for artificial insemination and embryo transfer in Brazil, overcoming several reproductive problems. Our goal is to develop cheap and easy self-appointed programs that facilitate animal handling and maximize their reproductive outcomes all over the year. Review: Failure in estrus detection is the mainly limiting factor for the use of artificial insemination in high-production dairy herd. An excellent alternative to overcome the need of estrus detection is fixed time artificial insemination. Many protocols with and without the use of estradiol have been developed to that end. Among the protocols for fixed time artificial insemination without estradiol, DoubleOvsynch has been extensively used recently in American dairy herds. In Brazil, similar pregnancy rate was obtained compared to progesterone-estradiol based protocols for fixed time artificial insemination. Particularities of progesterone-estradiol based protocols as (1) new progesterone device or devices previously used for eight days; (2) different doses of eCG; and (3) the use of estradiol cypionate for fixed time artificial insemination have been studied in Brazil. The use of self-appointed artificial insemination also enabled the reduction of the interval calving-conception compared to cows inseminated following the standing estrus. Regarding the low fertility of repeat breeders and the effect of heat stress at early pregnancy, other methods like embryo transfer became important tools to enhance reproductive efficiency of Brazilian dairy herds. Protocols were also developed to allow fixed time embryo transfer, eliminating the need of estrus detection and improving the reproductive efficiency of lactating recipients. As well as described for fixed time artificial insemination treatments, there is a large variety of hormone combination for fixed time embryo transfer (with and without estradiol). An experiment conducted in Brazil demonstrated that protocols for fixed time embryo transfer without estradiol can be as good as with estradiol to synchronize high-producing Holstein recipients, essentially during summer. Particularities related to embryos cryopreservation, synchronization of the estrus cycle of donors and recipients and the site of embryo release into the uterine horn were also investigated. Greater conception rates were achieved when fresh embryos were transferred compared to frozen-thawed ones. Also, the tight synchronization between donor and recipient (same day of estrus) resulted more pregnancies than when recipients were one day later or in advantage in relation to donors. Moreover, the site of embryo release into the uterine horn (ipsilateral to the corpus luteum) had no effect on pregnancy rates after in vivo produced embryo transfer. Conclusion: Both fixed time artificial insemination and fixed time embryo transfer are important tools to improve reproductive efficiency of high-producing dairy cows. These biotechnologies help bypassing some of the greatest challenges of dairy cattle reproduction: the difficulties of estrus detection, and the low fertility associated to heat stress and repeat breeding.

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Proficiency in management activities undertaken in product development processes is regarded as a key competitive advantage for companies, particularly for high-tech industrial firms, which benefit from the important competitiveness factor of launching products with a differentiated technological content. This paper's objective was to identify, through case study, practices for integration between the roles of R & D with others involved in product development in a large Brazilian company of industrial automation. The results suggest some management practices to improve the integration in new products development, such as the use of employees from marketing with knowledge and experience previously gained from R & D activities and uses the heavyweight product manager to solve synchronization problems between product and technology development. © Universidad Alberto Hurtado, Facultad de Economía y Negocios.

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Includes bibliography

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Riemann surfaces, cohomology and homology groups, Cartan's spinors and triality, octonionic projective geometry, are all well supported by Complex Structures [1], [2], [3], [4]. Furthermore, in Theoretical Physics, mainly in General Relativity, Supersymmetry and Particle Physics, Complex Theory Plays a Key Role [5], [6], [7], [8]. In this context it is expected that generalizations of concepts and main results from the Classical Complex Theory, like conformal and quasiconformal mappings [9], [10] in both quaternionic and octonionic algebra, may be useful for other fields of research, as for graphical computing enviromment [11]. In this Note, following recent works by the autors [12], [13], the Cauchy Theorem will be extended for Octonions in an analogous way that it has recentely been made for quaternions [14]. Finally, will be given an octonionic treatment of the wave equation, which means a wave produced by a hyper-string with initial conditions similar to the one-dimensional case.