The Laskeek Bay Conservation Society has been collecting data on the East Limestone Island population of Ancient Murrelets since 1990. For the first 15 years of this decades-long study, mark-recapture data was collected annually on the adult population using one method while chicks were captured and tagged each year soon after their birth using another method. We developed a Jolly-Seber type model that integrates the adult and chick data. Using a multi-state framework, our model separates the `alive' state of the JS model into several age-related states, allowing for different survival and capture parameters between states. In the Ancient Murrelet case study we found that a 6-state model with constant adult survival and capture parameters best fit the data. We determined that, since the detected chicks are rarely seen again, including these individuals in the model does not result in estimates which greatly differ from that of the standard Jolly-Seber model but in a population in which juveniles have high survival and re-capture probabilities, the MSJS model is able to reduce the bias in estimates of population parameters. / Graduate

No description available.

Maintenance management is to design, operate, and maintain the reliability and availability of assets at a required performance level using the lowest possible cost. The standby redundancy is one of the means to achieve highly reliable system with less dependable units. As commonly used performance indicator, the reliability and availability should be precisely analysed for a repairable standby system. The reliability of a standby system is mainly studied in the framework of lifetime approach. Most existing models are developed for a two-unit standby system and a Kout- of-N system with identical units. The system units are assumed to be binary-state and the failures of system units are modelled as sudden failures. The deteriorations of units are modelled as time-dependent failure rate and are assumed to be independent. In addition, most of the existing models do not consider maintenance is carried out on the system. In reality, the deteriorations and the resultant failures in real-world systems are often interactive with each other. The systems normally experience several, often imperfect, restorations before a complete renewal. Therefore, the study of different repair policies, such as opportunistic and individual policies, in multi-unit systems need also be investigated. To address the problem, the reliability and availability models for a 2-out-of-3 cold standby system will be studied in a multi-state system reliability framework. A multistate multi-path failure mode is proposed to model the interactive deteriorations. The concept of repair matrix will be adopted to model the effect of unit level restorations on system reliability. The availabilities under individual repair policy and opportunistic repair policy will be developed.

For many decades, the revolution in semiconductor industry has continuously been powered by the successful down scaling of complementary metal-oxide semiconductor (CMOS) technology to produce integrated circuits with improved performance at lower cost. However, current charge-based CMOS technology is already approaching physical limits and, thus, encounters a number of technological challenges. Spintronics is an emerging and rapidly evolving research field that has a great potential to overcome these challenges confronting CMOS by introducing the electron spin, in addition to electron charge, as an extra degree of freedom. Traditional spintronic devices are based on the alignment of spins in magnetic layers, manipulated by spin-polarized currents. Thus, employing the non-volatile nature of layer magnetization and its direction to represent the bit state, spintronics provides power-efficient devices that are attractive for memory and logic applications. Magnetoresistive random access memory (MRAM) is one of the most essential applications of spin based electronics, which has already been recognized as the leading candidate for future universal memory. MRAM cells use spin-based magnetic tunnel junctions (MTJs) as the fundamental storage blocks. These conventional MTJs employ the use of magnetic elements with a single axis of magnetization, which provide two resistance states, capable of storing one bit of information. Enhancing the memory density is one of the major challenges encountered by MRAM industry, as the straightforward approach of reducing the magnetic bit size is unfeasible with magnetic devices due to intrinsic superparamagnetism effects. In this thesis, we propose increasing the bit density in MRAM by implementing shape anisotropy induced multistate MTJs. By patterning the free ferromagnetic layer of MTJs in the shape of four intersecting ellipses we achieve four in-plane stable axes of magnetization, capable of providing eight resistance states in total, the switching between which is performed by spin-orbit torques (SOT) in spin Hall metals (SHM). We initially verify the proposed concept with micromagnetic simulations followed by fabrication and, consequent, room temperature characterization of the first experimental prototypes.

One-parent families in the East-Kazakhstan region Abstract This paper addresses single-parent families in the East-Kazakhstan region and their role in the development of population, as well as the analysis of extra-marital births and the factors of family dissolution, such as divorce and widowhood. The data used were taken from censuses in 1989 and 1999, vital statistics, results of surveys, adjusted data. The aim of the thesis is investigation of one-parent families' contribution to population development in the East-Kazakhstan region through analysis of their structure, size, historical and modern conditions of origin and socio-economical situation. Keywords: one-parent family, single-parent household, traditional and modern family, extra-marital birth, family dissolution, divorce, East-Kazakhstan region. Неполные семьи в Восточно-Казахстанском регионе

Loggerhead sea turtles (Caretta caretta) are listed as threatened under the Endangered Species Act and are protected both on nesting beaches and in United States waters. Loggerhead sea turtles are long-lived species and are most easily studied on the beaches during the nesting season. Bald Head Island, North Carolina has one of the highest density nesting beaches of loggerhead sea turtles in the turtle's northern range on the East Coast of the United States. Key life history parameters were estimated and applied to a population model using 16 years of data from a mark-recapture study on the loggerhead sea turtle nesting population on Bald Head Island, North Carolina. The beach survey conducted on the island only allowed for the capture of adult female sea turtles during the breeding state even though females may spend multiple years in the unobservable non-breeding state. The majority of females captured over the last 16 years have never been recaptured at the original capture site. These transients in the data coupled with unobservable states violate the assumption of equal catchability in the available single state mark-recapture models. Therefore, a multistate mark- recapture model originally developed for leatherback sea turtles was applied to the Bald Head Island loggerhead population. Multistate modeling provides a new technique to estimate sea turtle demographic parameters in which all model assumptions can be met. The multistate model outputs female survival rates, capture probability, and transition probabilities between breeding and non-breeding states. A correction factor for trap-dependence and transients was included given that both factors tested significant in the global model goodness-of-fit tests. The estimates of annual adult survival rate and breeding transitions were then used to project population size for the northern subpopulation. For the first time, estimation error around estimates of benthic juvenile and adult survival rates was included in a loggerhead sea turtle model. I explored the effects of estimation error, three levels of clutch frequency, and larger TED openings on population growth rate and on the probability of reaching a nesting recovery threshold. The nesting recovery threshold was based upon recovery criteria from the Federal Recovery Plan and set as the probability of reaching 12,800 nests/season in the states of North Carolina, South Carolina, and Georgia within a 50 year time period. The results of this study provide important information to guide future management and research. / Master of Science

Yes / In this paper, we will consider the selective maintenance problem for multistate series systems with stochastic dependent components. In multistate systems, the health state of a component may vary from perfect functioning to complete failure. The stochastic dependence (S-dependence) between components is discussed and categorized into two types in multistate context. First, the failure of a component can immediately cause complete failures of some other components in the system. Second, as components deteriorate, the reduced working performance rate of a multistate component affects the state as well as the degradation rate of its subsequent components in series structure. The system reliability is evaluated using an approach based on stochastic process. A cost-based selective maintenance model is developed for the multistate system with S-dependent components to maximize the total system profit, which includes the production gain and loss in the next mission as well as possible maintenance costs for the system. Analyses of systems with independent and dependent components are provided. It is observed that ignoring S-dependence in the system may lead to alternative maintenance decision making and an optimistic estimation of the system performance.

Competition among individuals over shared resources reveals asymmetries in quality resulting in the formation of dominance hierarchies. These hierarchies act as a mechanism for social selection by partitioning resources among group-living animals. The following chapters describe my dissertation research which investigates the factors contributing to competitive asymmetries among broodmates as well as the short- and long-term consequences of the early social environment for the cooperatively breeding red-cockaded woodpecker (Picoides borealis). My research revealed that fledgling red-cockaded woodpeckers form male-biased, linear dominance hierarchies. Among fledgling males,, high relative nestling condition strongly predicted fledgling dominance, and this condition–rank relationship persisted through independence. Male nestlings are slightly larger and heavier than females; however, the sexual size dimorphism in mass is only present in mixed-sex broods, suggesting that the subtle structural size advantage gives males a competitive advantage over their sisters. Conflict rates among siblings increased with decreasing targeted feeding rates, and dominant fledglings were able to secure more food from provisioning adults through scramble competition. First-year survival favored males over females and dominant males over subordinates. Females were more dispersive overall than males, and subordinate males were more likely to disperse than dominants. The social environment prior to fledging influenced male dispersal decisions and subordinates delayed dispersal in the spring in situations where all dominants died over the winter. The probability of delayed dispersal in females was higher for females raised without brood-mates in one of two populations included in a long-term demographic data analysis. The availability of breeding vacancies may explain the differences in female dispersal behavior according to social environment between these populations. This research contributes to a greater understanding of the relative contribution of intrinsic benefits versus extrinsic constraints as an influence on delayed dispersal decisions in red-cockaded woodpeckers. Inter- and intra-sexual social rank is correlated with individual access to natal food resources and the probability of first-year survival. The intrabrood variation in dispersal strategies driven by social rank is sufficient to regularly produce both dispersal strategies among males and provides additional support that delaying natal dispersal is the preferred strategy for males in this system. / Ph. D.

Frequentemente eventos intermediários fornecem informações mais detalhadas sobre o processo da doença ou recuperação, por exemplo, e permitem uma maior precisão na previsão do prognóstico de pacientes. Tais eventos não fatais durante o curso da doença podem ser vistos como transições de um estado para outro. A ideia básica dos modelos multiestado é que o indivíduo se move através de uma serie de estados em tempo contínuo, sendo possível estimar as probabilidades e intensidades de transição entre eles e o efeito das covariáveis associadas a cada transição. Muitos estudos incluem o agrupamento dos tempos de sobrevivência como, por exemplo, em estudos multicêntricos, e também é de interesse estudar a evolução dos pacientes ao longo do tempo, caracterizando assim dados multiestado agrupados. Devido ao fato de os dados virem de diferentes centros/grupos, os tempos de falha desses indivíduos estarem agrupados e a fatores de risco comuns não observados, é interessante considerar o uso de fragilidades para que possamos capturar a heterogeneidade entre os grupos no risco para os diferentes tipos de transição, além de considerar a estrutura de dependência entre transições dos indivíduos de um mesmo grupo. Neste trabalho apresentamos a metodologia dos modelos multiestado, dos modelos de fragilidade e, em seguida, a integração dos modelos multiestado com modelos de fragilidade, tratando do seu processo de estimação paramétrica e semiparamétrica. O estudo de simulação realizado mostrou a importância de considerarmos fragilidade sem modelos multiestado agrupados, pois sem considerá-las, as estimativas tornam-se viesadas. Além disso, verificamos as propriedades frequentistas dos estimadores do modelo multiestado com fragilidades aninhadas. Por fim, como um exemplo de aplicação a um conjunto de dados reais, utilizamos o processo de recuperação de transplante de medula óssea de pacientes tratados em quatro hospitais. Fizemos uma comparação de modelos por meio das medidas de qualidade do ajuste AIC e BIC, chegando à conclusão de que o modelo que considera dois efeitos aleatórios (uma para o hospital e outro para a interação transição-hospital) ajusta-se melhor aos dados. Além de considerar a heterogeneidade entre os hospitais, tal modelo também considera a heterogeneidade entre os hospitais em cada transição. Sendo assim, os valores das fragilidades estimadas da interação transição-hospital revelam o quão frágeis os pacientes de cada hospital são para experimentarem determinado tipo de evento/transição. / Often intermediate events provide more detailed information about the disease process or recovery, for example, and allow greater accuracy in predicting the prognosis of patients. Such non-fatal events during the course of the disease can be seen as transitions from one state to another. The basic idea of a multistate models is that the person moves through a series of states in continuous time, it is possible to estimate the transition probabilities and intensities between them and the effect of covariates associated with each transition. Many studies include the grouping of survival times, for example, in multi-center studies, and is also of interest to study the evolution of patients over time,characterizing grouped multistate data. Because the data coming from different centers/groups, the failure times these individuals are grouped and the common risk factors not observed, it is interesting to consider the use of frailty so that we can capture the heterogeneity between the groups at risk for different types of transition, in addition to considering the dependence structure between transitions of individuals of the same group. In this work we present the methodology of multistate models, frailty models and then the integration of models with multi-state fragility models, dealing with the process of parametric and semi-parametric estimation. The conducted simulation study showed the importance of considering frailty in grouped multistate models, because without conside- ring them, the estimates become biased. Furthermore, we find the frequentist properties of estimators of multistate model with nested frailty. Finally, as an application example to a set of real data, we use the process of bone marrow transplantation recovery of patients in four hospitals. We did a comparison of models through quality measures setting AIC and BIC, coming to the conclusion that the model considers two random effects (one for the hospital and another for interaction transition-hospital) fits the data better. In addition to considering the heterogeneity between hospitals, such a model also considers the heterogeneity between hospitals in each transition. Thus,the values of the frailty estimated interaction transition-hospital reveal how fragile patients from each hospital are to experience certain type of event/transition.

Wetlands of the Prairie Pothole Region of North America provide habitat for over 50% of the continent's breeding waterfowl, but most of the region's wetlands have been lost or degraded through intensive agricultural development. Despite widespread wetland losses in much of the Canadian prairies, there is little information about trends in degradation of remaining wetlands. Using habitat data collected for ~10,500 wetlands across the Canadian prairies during annual waterfowl surveys, 1985-2005, I employed multistate models in Program MARK to estimate rates of impact and recovery of wetlands resulting from agricultural activities. Then, I characterized the incidence of agricultural degradation to these wetlands. Rates of impact to wetland margins (natural vegetation around flooded basins) declined over time, likely due to a decreasing percentage of unaffected wetlands; recovery rates for margins were always lower than impact rates, suggesting increased cumulative degradation of wetlands over time. Unlike margins, impact and recovery rates for basins fluctuated with spring pond densities. Shallow ephemeral wetlands located in agricultural fields had the highest impact and lowest recovery rates. Multistate modeling could also be used to estimate rates associated with other landscape processes.<p><p> My second objective was to determine whether physical characteristics of prairie Canada wetlands could be used to predict breeding duck abundance. First, I sought to determine how pre-existing models developed in the Dakotas (USA) performed when predicting breeding duck abundances on Canadian prairie wetlands. I related duck pair abundance to pond area, and then compared observed to predicted duck abundance. The Dakota models performed reasonably well in predicting numbers of blue-winged teal (<i>Anas discors</i>), gadwall (<i>A. strepera</i>), and northern pintail (<i>A. acuta</i>), but predicted fewer mallards (<i>A. platyrhynchos</i>) and northern shovelers (<i>A. clypeata</i>) than were observed on wetlands. Pond area was an important predictor of duck abundance in all models, but results were less biased and more consistent in models developed specifically for Canadian wetlands. Spatiotemporal variation in the relationship of breeding duck abundance and wetland characteristics was also affected by regional duck and pond densities. Overall, the new applications and models developed and validated in this study will be useful for wetland and waterfowl management in the Canadian prairies.