Uniqueness criteria for continuous-time Markov chains with general transition structures

We derive necessary and sufficient conditions for the existence of bounded or summable solutions to systems of linear equations associated with Markov chains. This substantially extends a famous result of G. E. H. Reuter, which provides a convenient means of checking various uniqueness criteria for birth-death processes. Our result allows chains with much more general transition structures to be accommodated. One application is to give a new proof of an important result of M. F. Chen concerning upwardly skip-free processes. We then use our generalization of Reuter's lemma to prove new results for downwardly skip-free chains, such as the Markov branching process and several of its many generalizations. This permits us to establish uniqueness criteria for several models, including the general birth, death, and catastrophe process, extended branching processes, and asymptotic birth-death processes, the latter being neither upwardly skip-free nor downwardly skip-free.

On the Structure of Spatial Branching Processes

The paper is a contribution to the theory of branching processes with discrete time and a general phase space in the sense of [2]. We characterize the class of regular, i.e. in a sense sufficiently random, branching processes (Φk) k∈Z by almost sure properties of their realizations without making any assumptions about stationarity or existence of moments. This enables us to classify the clans of (Φk) into the regular part and the completely non-regular part. It turns out that the completely non-regular branching processes are built up from single-line processes, whereas the regular ones are mixtures of left-tail trivial processes with a Poisson family structure.

The role of Compton and Raman scattering in the quasar continuum

There are three ways in which an electromagnetic wave can undergo scattering in a plasma: (i) when the scattering of radiation occurs by a single electron, it is called Compton Scattering (CS); (ii) if it occurs by a longitudinal electron plasma mode, it is called Stimulated Raman Scattering (SRS), and (iii) if it occurs by a highly damped electron plasma mode, it is called Stimulated Compton Scattering (SCS). The non-thermal continuum of quasars is believed to be produced through the combined action of synchrotron and inverse Compton processes, which are essentially single-particle processes. Here, we investigate the role of SRS and SCS in the generation of continuum radiation from these compact objects. It is shown as an example that the complete spectrum of 3C 273 can be reproduced by suitably combining SCS and SRS. The differential contributions of SCS and SRS under different values of the plasma parameters are also calculated.

The diffusion and relaxation of Gaussian chains in narrow rectangular slits

The confinement of a polymer to volumes whose characteristic linear dimensions are comparable to or smaller than its bulk radius of gyration R-G,R-bulk can produce significant changes in its static and dynamic properties, with important implications for the understanding of single-molecule processes in biology and chemistry. In this paper, we present calculations of the effects of a narrow rectangular slit of thickness d on the scaling behavior of the diffusivity D and relaxation time tau(r) of a Gaussian chain of polymerization index N and persistence length l(0). The calculations are based on the Rouse-Zimm model of chain dynamics, with the pre-averaged hydrodynamic interaction being obtained from the solutions to Stokes equations for an incompressible fluid in a parallel plate geometry in the limit of small d. They go beyond de Gennes' purely phenomenological analysis of the problem based on blobs, which has so far been the only analytical route to the determination of chain scaling behavior for this particular geometry. The present model predicts that D similar to dN(-1) ln(N/d(2)) and tau(r) similar to N(2)d(-1) ln(N/d(2))(-1) in the regime of moderate confinement, where l(0) << d < R-G,R-bulk. The corresponding results for the blob model have exactly the same power law behavior, but contain no logarithmic corrections; the difference suggests that segments within a blob may actually be partially draining and not non-draining as generally assumed.

The diffusion and relaxation of Gaussian chains in narrow rectangular slits

The confinement of a polymer to volumes whose characteristic linear dimensions are comparable to or smaller than its bulk radius of gyration R-G,R-bulk can produce significant changes in its static and dynamic properties, with important implications for the understanding of single-molecule processes in biology and chemistry. In this paper, we present calculations of the effects of a narrow rectangular slit of thickness d on the scaling behavior of the diffusivity D and relaxation time tau(r) of a Gaussian chain of polymerization index N and persistence length l(0). The calculations are based on the Rouse-Zimm model of chain dynamics, with the pre-averaged hydrodynamic interaction being obtained from the solutions to Stokes equations for an incompressible fluid in a parallel plate geometry in the limit of small d. They go beyond de Gennes' purely phenomenological analysis of the problem based on blobs, which has so far been the only analytical route to the determination of chain scaling behavior for this particular geometry. The present model predicts that D similar to dN(-1) ln(N/d(2)) and tau(r) similar to N(2)d(-1) ln(N/d(2))(-1) in the regime of moderate confinement, where l(0) << d < R-G,R-bulk. The corresponding results for the blob model have exactly the same power law behavior, but contain no logarithmic corrections; the difference suggests that segments within a blob may actually be partially draining and not non-draining as generally assumed. (C) 2013 AIP Publishing LLC.

Medida da seção de choque difrativa simples dσ/d|t| a √s = 8 TeV no experimento CMS

A análise descrita nesta dissertação tem como objetivo a medida da seção de choque difrativa dσ/d|t| à energia no sistema do centro de massa de √s = 8 TeV. Os eventos usados para obter a seção de choque difrativa foram selecionados para processos de difração simples com um próton espalhado na região frontal e na região cinemática de 0,03 <|t| < 1,0 GeV e 0,03 < ξ < 0.1, usando os dados em comum obtidos em 2012 dos detectores CMS e TOTEM, o qual permite ter uma perspectiva mais detalhada do processo difrativo, devido à aceitação completa que oferece a combinação dos detectores. Os dados foram corrigidos devido à aceitação e eficiência do detector. A partir de uma parametrização exponencial da forma Ae ^Bt, o valor da inclinação do processo em que o próton espalhado é detectado em ambas as direções positiva da CMS é de B= -6,403 1,241 GeV- .

The association between maternity insurance, residence status and selected perinatal outcomes among Chinese women

Objective: To investigate the impact of maternity insurance and maternal residence on birth outcomes in a Chinese population. Methods: Secondary data was analyzed from a perinatal cohort study conducted in the Beichen District of the city of Tianjin, China. A total of 2364 pregnant women participated in this study at approximately 12-week gestation upon registration for receiving prenatal care services. After accounting for missing information for relevant variables, a total of 2309 women with single birth were included in this analysis. Results: A total of 1190 (51.5%) women reported having maternity insurance, and 629 (27.2%) were rural residents. The abnormal birth outcomes were small for gestational age (SGA, n=217 (9.4%)), large for gestational age (LGA, n=248 (10.7%)), birth defect (n=48 (2.1%)) including congenital heart defect (n=32 (1.4%)). In urban areas, having maternal insurance increased the odds of SGA infants (1.32, 95%CI (0.85, 2.04), NS), but decreased the odds of LGA infants (0.92, 95%CI (0.62, 1.36), NS); also decreased the odds of birth defect (0.93, 95%CI (0.37, 2.33), NS), and congenital heart defect (0.65, 95%CI (0.21, 1.99), NS) after adjustment for covariates. In contrast to urban areas, having maternal insurance in rural areas reduced the odds of SGA infants (0.60, 95%CI (0.13, 2.73), NS); but increased the odds of LGA infants (2.16, 95%CI (0.92, 5.04), NS), birth defects (2.48, 95% CI (0.70, 8.80), NS), and congenital heart defect (2.18, 95%CI (0.48, 10.00), NS) after adjustment for the same covariates. Similar results were obtained from Bootstrap methods except that the odds ratio of LGA infants in rural areas for maternal insurance was significant (95%CI (1.13, 4.37)); urban residence was significantly related with lower odds of birth defect (95%CI (0.23, 0.89)) and congenital heart defect (95%CI (0.19, 0.91)). Conclusions: whether having maternal insurance did have an impact on perinatal outcomes, but the impact of maternal insurance on the perinatal outcomes showed differently between women with urban residence and women with rural residence status. However, it is not clear what are the reason causing the observed differences. Thus, more studies are needed.

Medidas objetivas das carcaças e composição química do lombo de cordeiros alimentados e terminados com três níveis de proteína bruta em creep feeding

Objetivou-se avaliar o efeito de três níveis de proteína (15, 20 e 25% PB) na ração sobre as medidas objetivas das carcaças e do músculo Longissimus dorsi, os pesos e rendimentos dos cortes, além da composição química e maciez da carne de cordeiros Suffolk alimentados e terminados em creep feeding. Foram utilizados 15 cordeiros inteiros, originados de partos simples, abatidos ao atingirem peso vivo final de 28 kg. As carcaças foram mantidas em câmara de refrigeração a 5ºC, durante 24 horas, para registro das medidas objetivas, realizado após separação dos cortes comerciais, na meia-carcaça esquerda. A área do músculo Longissimus dorsi foi mensurada para determinação da área de olho de lombo (AOL cm²). No lombo esquerdo congelado, realizou-se a análise de composição química e, no direito, também congelado, o teste de maciez peloWarner Bratzler Shear Force. Os níveis de proteína bruta não influenciaram as medidas objetivas de carcaça nem as do músculo Longissimus dorsi. Houve efeito significativo para peso e rendimento da paleta, com superioridade para o tratamento contendo 25% de proteína bruta. Nas análises químicas do músculo Longissimus dorsi, observou-se efeito significativo para extrato etéreo, cinzas e maciez. No sistema de alimentação e terminação de cordeiros Suffolk em creep feeding, a ração formulada com farelo de soja como fonte protéica deve ser balanceada com 25% de proteína bruta por diminuir o teor de gordura e melhorar a maciez da carne e o peso e rendimento da paleta, sem afetar as medidas objetivas da carcaça, os demais pesos e os rendimentos dos cortes.

Efeito de diferentes níveis de proteína bruta na ração sobre o desempenho e as características de carcaça de cordeiros terminados em creep feeding

O experimento foi realizado com os objetivos de avaliar o efeito dos níveis de proteína bruta (15, 20 e 25%) na ração concentrada sobre o desempenho e as características de carcaça de cordeiros Suffolk alimentados em creep feeding e analisar economicamente esse sistema de produção. Foram utilizados 15 cordeiros inteiros, nascidos de partos simples, alimentados ad libitum com as rações experimentais duas vezes ao dia. Estimaram-se o consumo de médio diário de ração, pelo cálculo da quantidade fornecida e das sobras; o ganho de peso, pela pesagem dos animais a cada 14 dias; o peso vivo ao abate (PVA) dos cordeiros em jejum (16 horas); e o rendimento de carcaça quente, após abate e evisceração. O ganho médio diário foi influenciado pelos níveis de proteína, quando considerada a idade de abate como covariável. Não houve efeito significativo dos níveis de proteína sobre as características de carcaça. No sistema de alimentação e terminação de cordeiros Suffolk em creep feeding, a ração deve ser balanceada com 25% de proteína bruta, uma vez que esse nível proporcionou maior ganho de peso médio diário e não alterou as características de carcaça.

Multiwavelength electronic speckle pattern interferometry for surface shape measurement

Profilometry by electronic speckle pattern interferometry with multimode diode lasers is both theoretically and experimentally studied. The multiwavelength character of the laser emission provides speckled images covered with interference fringes corresponding to the surface relief in single-exposure processes. For fringe pattern evaluation, variations of the phase-stepping technique are investigated for phase mapping as a function of the number of laser modes. Expressions for two, three, and four modes in four and eight stepping are presented, and the performances of those techniques are compared in the experiments through the surface shaping of a flat bar. The surface analysis of a peach points out the possibility of applying the technique in the quality control of food production and agricultural research. (c) 2007 Optical Society of America.

Multi-wavelength holographic profilometry - art. no. 60272L

A novel method for surface profilometry by holography is presented. We used a diode laser emitting at many wavelengths simultaneously as the light source and a Bi12TiO20 (BTO) crystal as the holographic medium in single exposure processes. The employ of multi-wavelength, large free spectral range (FSR) lasers leads to holographic images covered of interference fringes corresponding to the contour lines of the studied surface. In order to obtain the relief of the studied surface, the fringe analysis was performed by the phase stepping technique (PST) and the phase unwrapping was carried out by the Cellular-automata method. We analysed the relief of a tilted flat metallic bar and a tooth prosthesis.

Desempenho e parâmetros fisiológicos de cabras em pastagem de capim-tobiatã (Panicum maximum cv. Tobiatã) suplementadas nas fases pré-parto

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genotype effect on carcass and meat quality of lambs finished in irrigated pastures in the semiarid Northeastern Brazil

The aim of this study was to compare four genetic groups of sheep on the carcass and meat quality traits. Thirty-three contemporary and unrelated male lambs, all of single birth were used in the experiment, being thirteen from the Santa Inês (SI) breed, seven from the Brazilian Somali breed (BS), six from the Morada Nova (MN) breed and seven from the ½ Dorper - ½ Morada Nova (F1) crossbreed. The genotypes SI, BS and F1 presented similar performances in relation to hot and cold carcass weights, which values were 10.76±0.53kg and 10.46±0.52kg for SI, 9.20±0.73kg and 8.99±0.71kg for BS, and 9.35±0.73kg and 9.13±0.71kg for F1, respectively. The BS had a better hot carcass yield (47.10±0.88%) and cold carcass yield (46.00±0.87%). Better carcass conformation was observed in SI and F1 (2.73±0.12 and 2.50±0.17, respectively) while the BS presented a better finishing (3.29±0.20). The average for the rib eye area (REA) was 9.94±0.49cm², 8.66±0.67cm², 7.18±0.72cm² and 9.8±0.67cm², and for the carcass compactness index (CCI) it was 0.17±0.01kg/cm, 0.17±0.01kg/cm, 0.11±0.01kg/cm and 0.16±0,01kg/cm, for SI, SB, MN and F1, respectively. There were no significant differences between SI, BS and F1 regarding REA and CCI. Although, in general, the MN presented a relatively lower performance than the other genotypes, this breed had similar carcass yields and fat thickness when compared to SI and F1 and similar conformation and REA in comparison to the BS. Regarding meat quality, no differences were observed between genotypes, except for redness and cooking losses. It is concluded that no one group had a higher or lower performance in all traits analyzed. Moreover, for the management conditions employed in this study, there was evidence of greater specialization in meat production for genotypes SI, BS and F1 when compared to MN, although there are no substantial differences between the four groups regarding meat quality.

Desempenho reprodutivo de ovelhas mestiças da raça Santa Inês em Brachiaria humidícula e efeito do sexo no ganho de peso de cordeiros

The purpose was to evaluate the reproductive performance of woolless ewes due to the feeding management of offsprings and weaning age in addition to measuring the effect of gender on weight gain of lambs. Sixty-four Santa Inês crossbred ewes were distributed in a completely randomized design in a factorial 4 x 2 x 2 - four weaning ages (56, 70, 84 and 98 days), sex and feeding management of the offspring, each treatment with four replications. The ewes were managed with the offsprings at the foot in 14 paddocks of 1,5 or 2,0 hectares, formed with Brachiaria humidícola. The offsprings were born by single birth, of Santa Inês pure of origin (PO). After the weaning of all groups, sixty-four lambs (32 males and 32 females) were randomly assigned in individual stalls and confined for 30 days. The comparison of the parameters was carried out by the adjustment of the simple linear regression model. It was verified over time addiction of the offspring feed management of + 3,7% (P<0,05) for the calving intervals and of + 1,4% (P<0,05) for the service period. There was increasing linear effect (P<0,05) of weaning age on calving intervals and service period. It was verified over time, addiction of the offspring sex of + 2,0% (P<0,05) for the calving intervals and + 0,8% (P<0,05) for the ewes service period. It was observed over time addiction of sex of + 35,2% and + 36,9% (P<0,05), respectively, for the daily weight gain of lambs from birth to weaning and post-weaning in feedlot. The supplementation of the offspring in private feeder and the anticipation of the weaning age reduce the calving intervals and the service period of woolless ewes in Brachiaria humidicula pasture. The offspring sex is the source of variation in the analysis of reproductive efficiency of ewe's mat rices and in the weight gain of Santa Inês crossbred lambs from birth to weaning, and after weaning.

Stochastic modelling of the invasion process of nematodes in fly larvae

Stochastic models based on Markov birth processes are constructed to describe the process of invasion of a fly larva by entomopathogenic nematodes. Various forms for the birth (invasion) rates are proposed. These models are then fitted to data sets describing the observed numbers of nematodes that have invaded a fly larval after a fixed period of time. Non-linear birthrates are required to achieve good fits to these data, with their precise form leading to different patterns of invasion being identified for three populations of nematodes considered. One of these (Nemasys) showed the greatest propensity for invasion. This form of modelling may be useful more generally for analysing data that show variation which is different from that expected from a binomial distribution.