<p>This thesis examines parental condition, how it is traded off against reproduction and how it is displayed in a secondary sexual trait. The studies were performed on nest-box breeding collared flycatchers Ficedula albicollis on the island of Gotland, in the Baltic Sea. Early breeding and high fitness were found to be associated with high levels of glycosylated haemoglobin possibly governed by migratory exertion and infectious disease. In order to test if immune function is expressed in secondary sexual traits and how it is traded off against reproductive effort a series of experiments were performed, in which birds were challenged with an antigen, via a vaccine containing neutralised paramyxovirus. The forehead patch of the male collared flycatcher serves as a badge of status and is under sexual selection. Good condition, as reflected in strong immune response and low levels of blood parasites was found to be associated with bigger patch size. Patch size was also found to vary in size within the same breeding season in a pattern predictable from immune response data. Immune response, in itself, was found to be costly in terms of reduced survival, confirming that trade-offs involving suppression of immune response may increase fitness. Mating effort was found to be traded off against immune function and moult. Experimental brood size manipulations revealed a trade-off females between number of offspring and immune function. Thus I suggest a set of parameters useful for condition estimation. I also show that immune response is costly and, second, that pathogen resistance probably plays an important role in the shaping of secondary sexual traits and life-history decisions.</p>

Understanding the wide range of outcomes achieved by firms trying to implement TQM and similar process improvement initiatives presents a challenge to management science and organization theory: a few firms reap sustained benefits from their programs, but most efforts fail and are abandoned. A defining feature of such techniques is the reliance on the front-line workforce to do the work of improvement, thus creating the possibility of agency problems; different incentives facing managers and workers. Specifically, successfully improving productivity can lead to lay-offs. The literature provides two opposing theories of how agency interacts with the ability of quality-oriented improvement techniques to dramaticlly increase productivity. The 'Drive Out Fear' school argues that firms must commit to job security, while the 'Drive In Fear' school emphasizes the positive role that insecurity plays in motivating change. In this study a contract theoretic model is developed to analyze the role of agency in process improvement. The main insight of the study is that there are two types of job security, internal and external, that have opposite impacts on the firm's abilty to implement improvement initiatives. The distinction is useful in explaining the results of different case studies and can reconcile the two change theories. / National Science Foundation, grant SBR-9422228, the Ford Motor Company and the Harley-Davidson Motor Company. MIT Sloan School of Management, Center for Innovation in Product Development

This thesis examines parental condition, how it is traded off against reproduction and how it is displayed in a secondary sexual trait. The studies were performed on nest-box breeding collared flycatchers Ficedula albicollis on the island of Gotland, in the Baltic Sea. Early breeding and high fitness were found to be associated with high levels of glycosylated haemoglobin possibly governed by migratory exertion and infectious disease. In order to test if immune function is expressed in secondary sexual traits and how it is traded off against reproductive effort a series of experiments were performed, in which birds were challenged with an antigen, via a vaccine containing neutralised paramyxovirus. The forehead patch of the male collared flycatcher serves as a badge of status and is under sexual selection. Good condition, as reflected in strong immune response and low levels of blood parasites was found to be associated with bigger patch size. Patch size was also found to vary in size within the same breeding season in a pattern predictable from immune response data. Immune response, in itself, was found to be costly in terms of reduced survival, confirming that trade-offs involving suppression of immune response may increase fitness. Mating effort was found to be traded off against immune function and moult. Experimental brood size manipulations revealed a trade-off females between number of offspring and immune function. Thus I suggest a set of parameters useful for condition estimation. I also show that immune response is costly and, second, that pathogen resistance probably plays an important role in the shaping of secondary sexual traits and life-history decisions.

This study investigated factors associated with two mortality events: avian botulism in waterfowl and mortality associated with hatching asynchrony in prefledgling Franklins gulls (Larus pipixcan). The initial focus of my research was on the spatiotemporal relationship between mortality of Franklins gulls and the onset of botulism outbreaks in waterfowl, and the suitability of gull carcasses for proliferation and toxigenesis of Clostridium botulinum. From 1999 to 2001, dead hatch-year Franklins gulls were by far the most abundant carcasses, and the only source of toxin-laden maggots found on transects prior to the occurrence of avian botulism in waterfowl. Nest density was a significant predictor of hatch-year gull carcass density. High density of toxic material from gull carcasses prior to the onset of botulism in waterfowl coincided with high densities of susceptible birds; hence, mortality of Franklins gulls has the potential to be a major initiating factor for botulism outbreaks at Eyebrow Lake, Saskatchewan. The causes of gull mortality were conditions or diseases associated with starvation, stress, or immunosuppression, and most mortality occurred in third-hatched chicks. To separate effects of laying order from effects of hatching asynchrony on prefledgling survival, a cross-fostering experiment was conducted to create clutches containing asynchronously hatching eggs of the same laying order, and of similar egg mass, egg volume, and female quality. Hatching order, independent of laying order, significantly affected survival to fledging, whereas laying order had no observable effect, indicating that intraclutch variation in egg quality does not predetermine the fate of prefledglings, and may be less important than hatching asynchrony for survival of prefledgling Franklins gulls. Relationships among hatching asynchrony, laying order, mass, corticosterone, immune function, growth, and survival at two stages of development were complex. Hatching asynchrony significantly affected early and late prefledgling survival, and was directly or indirectly associated with mass, corticosterone level, and cell-mediated immune responses at early and later stages of development. Both hatching asynchrony and mass appeared to play key roles in mediating life history trade-offs among cell-mediated immune function, growth, and survival. In contrast to cell-mediated immune responses, primary humoral immune response was not directly affected by hatching order or mass, nor was it associated with survival to fledging. Rather, it was associated with laying order, neonatal testosterone, corticosterone at 2 weeks, growth of leg length, and clutch initiation date, illustrating the importance of examining more than one branch of the immune system in studies of life history trade-offs. This study is a step toward using a multipronged and multidisciplinary approach to demonstrate interactions and trade-offs among life history traits, the physiological mechanisms that produce these relationships, and how these relationships may change depending on stage of development.

This study investigated factors associated with two mortality events: avian botulism in waterfowl and mortality associated with hatching asynchrony in prefledgling Franklins gulls (Larus pipixcan). The initial focus of my research was on the spatiotemporal relationship between mortality of Franklins gulls and the onset of botulism outbreaks in waterfowl, and the suitability of gull carcasses for proliferation and toxigenesis of Clostridium botulinum. From 1999 to 2001, dead hatch-year Franklins gulls were by far the most abundant carcasses, and the only source of toxin-laden maggots found on transects prior to the occurrence of avian botulism in waterfowl. Nest density was a significant predictor of hatch-year gull carcass density. High density of toxic material from gull carcasses prior to the onset of botulism in waterfowl coincided with high densities of susceptible birds; hence, mortality of Franklins gulls has the potential to be a major initiating factor for botulism outbreaks at Eyebrow Lake, Saskatchewan. The causes of gull mortality were conditions or diseases associated with starvation, stress, or immunosuppression, and most mortality occurred in third-hatched chicks. To separate effects of laying order from effects of hatching asynchrony on prefledgling survival, a cross-fostering experiment was conducted to create clutches containing asynchronously hatching eggs of the same laying order, and of similar egg mass, egg volume, and female quality. Hatching order, independent of laying order, significantly affected survival to fledging, whereas laying order had no observable effect, indicating that intraclutch variation in egg quality does not predetermine the fate of prefledglings, and may be less important than hatching asynchrony for survival of prefledgling Franklins gulls. Relationships among hatching asynchrony, laying order, mass, corticosterone, immune function, growth, and survival at two stages of development were complex. Hatching asynchrony significantly affected early and late prefledgling survival, and was directly or indirectly associated with mass, corticosterone level, and cell-mediated immune responses at early and later stages of development. Both hatching asynchrony and mass appeared to play key roles in mediating life history trade-offs among cell-mediated immune function, growth, and survival. In contrast to cell-mediated immune responses, primary humoral immune response was not directly affected by hatching order or mass, nor was it associated with survival to fledging. Rather, it was associated with laying order, neonatal testosterone, corticosterone at 2 weeks, growth of leg length, and clutch initiation date, illustrating the importance of examining more than one branch of the immune system in studies of life history trade-offs. This study is a step toward using a multipronged and multidisciplinary approach to demonstrate interactions and trade-offs among life history traits, the physiological mechanisms that produce these relationships, and how these relationships may change depending on stage of development.

No description available.

The main purpose of this study was to evaluate the effect of alternative cropping systems on farm net returns, and nitrate-N and sediment yields in Thomas Brook Watershed (TBW). The study involved integrated bio-physical and economic optimization modelling. Crop yield and nitrate-N pollution response functions were estimated and then used in trade-off analysis between farm returns and environmental quality improvement. Five crop rotation systems were evaluated for seven fertilizer levels under conventional tillage (CT) and no-till systems (NT). Nitrate-N leached, as well as estimated maximum economic rate of N (MERN) fertilizer level and marginal abatement costs depended on crop type, rotation system, and tillage type. The most cost effective cropping systems that met restrictions on Health Canada maximum limit on nitrate-N in water included corn-corn-corn-alfalfa-alfalfa under NT for corn-based cropping systems, potato-winter wheat-carrot-corn under CT for vegetable horticulture-based and potato-barley-winter wheat-potato-corn under NT for potato-based cropping systems.

The two main goals of my thesis were to further our understanding of how parental effort is related to life-history trade-offs and to see how parental investment is reflected in various potential measures of nestling quality. I looked at how fitness is maximized by examining (1) the trade-off between current and future reproduction, and (2) the trade-off between quantity and quality of offspring. To see how parents responded to energetic demands and whether each sex reacted in a similar way, I experimentally manipulated brood sizes and quantified provisioning rates. Both male and female parents with enlarged broods increased their feeding rates, but provisioning on a per nestling basis declined, so that parents fledged lighter nestlings with shorter wings. Although the incidence of mortality did not differ between control and enlarged broods, nestlings from enlarged broods were lighter than those from control broods with the same brood size, suggesting that clutch size may be individually optimized. I also looked at how nestlings responded to different levels of nutritional stress in the manipulated broods by quantifying size and body condition, plumage colouration, and the physiological measures of T-cell mediated immune responses, and corticosterone levels in nestling feathers as a long-term integrated measure of stress physiology. The size of melanin ornaments on feathers and the saturation and brightness of carotenoid colouration was associated with nestling mass in such a way that suggested that plumage characteristics reflect nestling quality. The immune function of nestlings was negatively related to brood size and nestlings in better body condition could mount greater immune responses to foreign antigens suggesting that immune responses are energetically costly. Corticosterone levels in the feathers were not related to nestling body condition and were unaffected by the experimental brood manipulation. The ii mass of male nestlings, which are the larger sex, was more compromised by brood size than female mass was. I also found sex-specific relationships between plumage characteristics and measures of physiological performance. These findings help to explain optimal clutch size and the classic trade-off between quality and quantity of offspring. They also offer new insights into the reliability of putative measures of quality in nestlings and relationships between physiological and morphological traits.

Made available in DSpace on 2010-04-20T20:20:49Z (GMT). No. of bitstreams: 1 80466.pdf: 340768 bytes, checksum: 85d732009ef598703c453f5ccfe4574b (MD5) Previous issue date: 2006-04-19T00:00:00Z / Esta pesquisa tem como principal objetivo gerar conhecimento estruturado sobre o tema de gestão integrada das operações numa organização de bens de consumo, por meio da arquitetura organizacional. Serão analisados os elementos do modelo organizacional, assim como o alinhamento entre a estratégia, o modelo organizacional, os incentivos e geração de valor para a empresa. O desenvolvimento da dissertação acontece fundamentado no estudo de caso da Philips – Divisão de Iluminação.

The primary aim of this survey is to: * explore whether there is potential for job-sharing in the South African labour market; * * describe the characteristics of potential job-sharers and to explain why Job-sharing would be an appropriate and feasible solution to unemployment, massive retrenchments, poor quality ofwork life (QWL) and low worker productivity Job-sharing has been used in many developed countries to address a variety of problems at the individual, organisational and national level. These include allowing workers to have a balance between their work and non-work life; to increase worker productivity and QWL and to increase employment opportunities. The literature survey affirms that these problems are prevalent in Africa as a whole and in South Africa specifically. The survey results reveal that the environment in South is Africa is conducive to jobsharing and that slightly over one third of the workers and organisations and two thirds of the jobseekers are willing to job-share. The results of this study also reveals that QWL, productivity and unemployment does influence the willingness to job-share and that approximately 80% of the employees would rather either job-share, work-share or opt for some other alternative than to have retrenchments. Thus by implication, job-sharing would address the problems relating to poor QWL, low worker productivity, fewer employment opportunities, as well as massive retrenchments in South Africa. The study has also explored possible reasons and obstacles to job-sharing and found that whether these are perceived as significantly important or not, depends on whether one is an employer, employee or job-seeker . The job-seekers feel more than others, that there is no reason insurmountable or obstacle preventing the introduction of job-sharing by which to avert their unemployed status. There are also differences in willingness to job-share among subgroups with regard to the industry, area of work, position held in the organisation and the availability of job-sharing positions in the organisation. This thesis reports that there is potential for job-sharing in the South African labour market, to address a variety of problems pertaining to workers, organisations, job-seekers and, therefore, the whole nation at large. / Business Management / D.B.L.