No description available.

No description available.

Sonoran Desert Drosophila mettleri breeds in soil soaked by the necrotic cacti juices from saguaro (Carnegiea gigantea) and cardon (Pachycereus pringlei). An isolated population on Santa Catalina Island, 300 kilometers NW of the Sonoran Desert limit, was discovered breeding in several Opuntia cacti species. Host shifts are associated with the speciation process in phytophagous insects. I tested for evidence of premating isolation, postmating isolation, and ecological differences among allopatric populations of Drosophila mettleri using a variety of approaches. No sexual isolation was detected. However, Drosophila mettleri from Santa Catalina Island shows significant behavioral and physiological differences compared with Sonoran Desert populations. Furthermore, Drosophila mettleri from Santa Catalina Island was significantly genetically differentiated from all other populations in the study. Finally, I observed sufficiently significant F1 male sterility in crosses involving the Santa Catalina Island population to consider it indicative of early postzygotic isolation.

This programme of research uses choice test methodologies to quantify hungry broiler breeder chickens’ preferences for qualitative or quantitative dietary restriction. It begins with an outline of quantitative dietary restriction, its severity and welfare implications before discussing methods of qualitative feed restriction and the difficulties ascertaining whether it represents a welfare improvement. Chapter two reviews the factors affecting diet preferences and discusses implications for feed restricted broiler breeder diet preferences. Chapter three outlines the use of a closed economy T-maze task to quantity the diet preferences of feed restricted broiler breeders. It concludes that broiler breeders can learn a food versus no food task but find it very difficult to learn a task in which both of the options are rewarded with food and this impeded diet preference quantification. Chapter four demonstrates that severity of feed restriction underlies these difficulties in learning. In Chapter five, a conditioned place preference task to identify the effects of diets on affective state (hunger versus satiety) is reported. A method validation group demonstrated that broilers show a state dependent preference for an environment associated with ad libitum access to food. However, birds failed to show a preference between an environment associated with quantitative dietary restriction and one associated with qualitative dietary restriction. Chapter six applies state- dependent learning (SDL) to quantifying the satiating effects of quantitative and qualitative dietary restriction. However, a validation group suggested that SDL preferences were probably an artefact of the test rather than a genuine state-led preference. Finally, the overall conclusion that no evidence was found that broiler breeders want, or that their welfare is improved by, qualitative feed restriction was drawn. However, the conditions under which a preference was reliably observed and the presence of hunger – state dependent effects on learning and expression of learnt preferences complicates the interpretation of any findings. Recommendations for further research are highlighted.

Submitted by MICHELE BERNARDINO DE LIMA null (michele_bernardino@yahoo.com.br) on 2016-05-16T15:00:37Z No. of bitstreams: 1 Michele_Bernardino_de _Lima.pdf: 1682251 bytes, checksum: febd0010dceb761ccc4f0391786d0513 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-05-17T13:36:34Z (GMT) No. of bitstreams: 1 lima_mb_dr_jabo.pdf: 1682251 bytes, checksum: febd0010dceb761ccc4f0391786d0513 (MD5) / Made available in DSpace on 2016-05-17T13:36:34Z (GMT). No. of bitstreams: 1 lima_mb_dr_jabo.pdf: 1682251 bytes, checksum: febd0010dceb761ccc4f0391786d0513 (MD5) Previous issue date: 2016-02-22 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Objetivou-se com esta pesquisa: 1) determinar as exigências de mantença de valina (Val), isoleucina (Ile) e triptofano (Trp) digestível utilizando diferentes sistemas de unidade; 2) avaliar as respostas de aves reprodutoras pesadas para diferentes ingestões de Val, Ile e Trp, determinar a eficiência de utilização e desenvolver um modelo fatorial; 3) calcular a ingestão ótima econômica de Val, Ile e Trp para aves reprodutoras pesadas utilizando o Modelo de Reading; 4) determinar as exigências de arginina digestível para manutenção utilizando diferentes sistemas de unidades; avaliar as respostas de aves reprodutoras pesadas para diferentes ingestões de arginina, estimar os parâmetros do Modelo de Reading pelo método da simulação e equação para aves reprodutoras pesadas e calcular a ingestão ótima econômica de arginina, considerando a relação entre custo-benefício e a variabilidade da população. Para o objetivo 1 foram realizados três ensaios utilizando 144 galos Cobb 500. A exigência de mantença foi obtida pela relação entre a ingestão do aminoácido e o nitrogênio retido. Os diferentes sistemas de unidade foram: mg/kg de peso corporal, mg/kg de peso metabólico e mg/kg de peso proteico. Para o objetivo 2 foram realizados três ensaios utilizando 192 aves reprodutoras pesadas. Os dados obtidos foram ingestão do aminoácido (IAA), peso corporal (PC) e massa de ovo (MO). O modelo modificado para calcular as exigências dos aminoácidos foi: IAA=[AAm×(PC×0,196)0,73]+[(Novo×MO×AAovo)/k], onde AAm é o aminoácido para mantença, Novo é o nitrogênio do ovo, AAovo é o aminoácido do ovo e k é a eficiência de utilização. Para o objetivo 3 utilizou-se os dados de AAI, MO e PC do objetivo 2 que foram ajustados pelo modelo de Reading. Para determinar as exigências dos aminoácidos pelo método da simulação foram utilizados 10.000 aves. Para o objetivo 4 foram realizados dois ensaios, o primeiro utilizando 42 galos Ross e o segundo utilizando 64 aves reprodutoras pesadas Ross. Os procedimentos utilizados foram semelhantes aos objetivos 1, 2 e 3. As conclusões obtidas foram: A exigência de manutenção é mais adequadamente expressa como teor de proteína corporal. A predição do modelo foi melhorado utilizando os coeficientes estimados com unidades fisiologicamente relevantes. O modelo de Reading pode ser utilizado para estimar as ingestões ótimas de aminoácidos para galinhas sob diferentes cenários genéticos e econômico e, dependendo dos ingredientes disponíveis e seus preços, o custo de cada um dos aminoácidos pode variar. / The objective of this research were: 1) determine the requirements for maintenance of valine (Val), isoleucine (Ile) and tryptophan (Trp) digestible using different unit systems; 2) evaluate the responses of broiler breeder hens to different intakes of Val, Ile and Trp, determine the efficiency of utilization and develop a factorial model; 3) calculate the economic optimum intake of Val, Ile and Trp for broiler breeder hens using the Reading Model; 4) determine the digestible arginine requirements for maintenance using different unit systems; evaluate the responses of broiler breeder hens to different intakes of arginine, estimate the parameters of the Reading Model by the method of simulation and equation for broiler breeder hens and calculate the economic optimum intake of arginine, considering the relationship between costbenefit and flock variability. For the objective 1 were conducted three trials using 144 Cobb 500 roosters. The requirement for maintenance was obtained by the relationship between amino acid intake and nitrogen retention. The different unit systems were: mg/kg of body weight, mg/kg of metabolic weight (BW0.75) and metabolic protein weight at maturity (BPm 0.73×u).For the objective 2 were conducted three trials using 192 Cobb 500 broiler breeder hens. The data obtained were: amino acid intake (AAI), body weight (BW) and the egg output (EO). The modified model to calculate the requirements of amino acids was: AAI=[AAm ×(BW×0.196)0.73]+[(Negg×EO×AAegg)/k] where AAm is the amino acid for maintenance, Negg is nitrogen egg, AAegg amino acid in egg, k is efficiency of utilization. For the objective 3 was used the AAI, EO and BW data from objective 2 that were adjusted by Reading Model. To determine the requirements of amino acids by the simulation method were used 10,000 birds. For objective 4 were conducted two trials, the first using 42 Ross roosters and the second trial using 64 Ross broiler breeder hens. The procedures used were similar to the objectives 1, 2 and 3. The conclusions obtained were: The maintenance requirement is more appropriately expressed as body protein content. The prediction of the model was improved using the coefficients estimated here with physiologically relevant units. The Reading Model could be used to estimate the optimum amino acid intakes for hens under different genetic and economic scenarios and depending on the ingredients available and their prices, the cost of each amino acid will vary. / FAPESP: 2013/13957-1

From large-scale agriculture and farming to concentrated fishing discards, garbage dumps, game carcasses and bird feeders, human action has been increasingly affecting natural systems and animal species through the deliberate and unintentional provisioning of food resources. Anthropogenic food sources (AFSs) are often more spatially concentrated, easily accessible, abundant and stable than natural food sources. The common raven, Corvus corax, is a behaviourally flexible and ecologically adaptable species that has managed to thrive in human transformed landscapes by exploiting these anthropogenic sources of food. The aim of this research was to investigate how raven individuals vary in their use of different AFSs through space and time. I used data from a long-term GPS tracking initiative in the Upper Austrian Alps to investigate (1) the space-use of non-breeding raven individuals across this landscape to answer the questions: (2) what types of AFSs are most extensively used by ravens in this landscape, and what factors predict individual variation in AFS use (i.e., apparent reliance on and access to resources), specifically (3a) the number of AFSs visited and (3b) the probability of being at AFSs at any given point in time. Movement patterns can reveal information on the foraging decisions made by individuals, including how they use different AFSs. Non-breeding raven individuals exhibited great variation in how they moved around and used the landscape. The number of AFSs visited, but not the probability of being at an AFS (at any given point in time), varied among individuals with different ranging behaviour and of different age class (i.e., juvenile and adults) and origin (i.e., captive-bred-released and wild-caught), suggesting that experience affects AFS-use. Non-breeders differed in their use of AFSs by season, visiting the highest number of AFSs but having the lowest probability being present at an AFS in winter, potentially indicative of high foraging competition under stressful environmental conditions. They were also found to extensively exploit resources in spring, both visiting high numbers of AFSs and having a high probability of being present at an AFS, perhaps due to decreased competition (e.g., from breeders) and increases in food availability. The category (i.e., wildpark, refuse site, hut) of AFSs also influenced the probability of an individual being present at the site, likely because of differences in resource quality, quantity and replenishing rate. A very few foraging sites were highly popular, while over half attracted less than 5 individuals throughout the study. By exploiting AFSs, raven population numbers have increased across their range, raising conservation concerns (i.e., predation on threatened species and human-wildlife conflict). With a better understanding of the patterns of AFS-use and the factors influencing these patterns, I suggest that strategies to manage ravens in this semi-transformed, alpine environment should focus on controlling the supply of food at AFSs at a regional scale.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 145-147. / by Wee Tee Loh. / M.S.

Inservice property degradation is known to occur in fuel clads of reactors systems currently in operation and under design_ Irradiation, corrosion, diffusion induced mass transfer, and a host of mechanical influences constitute the complex environmental variables responsible for the degradation. The degradation could occur in the bulk of the clad or through its thickness depending on the component of the environment and the reactor operating history. Synergistic influences of more than one component of the environment must also be considered. From the mechanics viewpoint, the degraded alloy is a material with nonuniform properties. Thus, the basic stress-strain relations require modifications which are functions of the reactor operating history. The nature of the balance equations of stress equilibrium changes, especially if the degradation occurs through the thickness of the material. Prescription of the complete stress-strain relationship is required for an elastic-plastic type of analysis at the beginning of each new time step in modeling the performance of the material. Knowledge of the metallurgical and mechanical nature of the degraded alloy and the spatial variation of the properties which result is a prerequisite for the modeling. Evidence from available literature is presented to illustrate this problem. The study involves the degradation of the 316 type stainless steel considered for use in Liquid Metal Fast Breeder Reactors where sodium is used as the coolant. Nonuniform changes in properties of the steel have been found to occur due to the thermal, thermochemical, and irradiation environment to which it is exposed. Variations in imparity concentrations (such as carbon in the steel) of several orders of magnitude compared to the original values have been observed under controlled sodium exposures. At temperatures relevant to the reactor system migration of impurities by diffusion, compound formations and carburization/decarburization behavior have been observed to occur. Mechanical property measurements such as tensile and yield strengths made under these conditions indicate that thermal and thermochemical influences can result in variations in the above properties quite different from the original material. Modified formulations of the elastic and elastic-plastic analysis of the degraded fuel-clad are presented in two dimensions. The elastic and plastic parameters relating to the properties of the degraded material are represented by spatially varying functions as opposed to being treated as constants which is the conventional case. The changes in the mathematical nature of the constitutive equations are demonstrated by sample illustrations and solutions involving continuous changes in the elastic moduli through-the-thickness of the clad. Recommendations for the establishment of improved Reactor Research Development Standards are made based on the studies. / Ph. D.

The delayed neutron spectra for LMFBRs are not as well known as those for LWRs. These spectra are necessary for kinetics calculations which play an important role in safety and accident analyses. In this study, a sensitivity analysis was performed to study the sensitivity of the reactor power and power density to uncertainties in the delayed neutron spectra during a rod ejection accident. The generalised methodology, developed by Cacuci et. al., was used to derive a set of sensitivity derivatives. This method is based on the use of adjoints so that it is not necessary to repeatedly solve the governing (kinetics) equations to obtain the sensitivity derivatives. This is of particular importance when large systems of equations are used. A two-energy multigroup and two precursor group model was formulated for the INFCE reference design MOX-fuelled LMFBR. The accidents studied were central control rod ejections with ejection times of 2, 10, and 30 seconds. The power and power density responses were found to be most sensitive to uncertainties in the spectrum of the second delayed neutron precursor group, resulting from the fission of U-238, producing neutrons in the first energy group. It was found, for example, that for a rod ejection time of 30 seconds, an uncertainty of 7.2% in the fast components of the spectra resulted in a 24% uncertainty in the predicted power and power density. These responses were recalculated by repeatedly solving the kinetics equations. The maximum discrepancy was only 1.6%. The versatility and accuracy of Cacuci’s methodology has been demonstrated. The results of the sensitivity analysis indicates the need for improved delayed neutron spectral data in order to reduce the uncertainties in the accident analyses. The model can be extended by using more energy groups, more precursor groups, and more spatial dimensions. Other important responses that may be studied are the linear power density, linear heat rate, and reactivity worths. / Ph. D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / by King-Wo Thomas Chiu. / M.S.