Dissertations / Theses on the topic 'HEXRD'

La formation des microstructures est cruciale pour la sidérurgie. Pour les aciers Dual Phase (DP), utilisés dans l'automobile, celle-ci a lieu lors du recuit intercritique après le laminage à froid. Après la chauffe, la microstructure est composée de ferrite et d'austénite recristallisées. Lors du refroidissement, l'austénite se transforme partiellement en ferrite puis en martensite pour atteindre la microstructure ferrite/martensite finale. L'austénitisation est cruciale pour contrôler les fractions et tailles de phase finales et donc leurs propriétés mécaniques. De nombreuses études montrent que la vitesse de chauffe contrôle la cinétique de transformation et la morphologie de l'austénite ("collier" ou "bande"). Ces effets sont souvent attribués au chevauchement entre la recristallisation de la ferrite et la formation de l'austénite, mais les mécanismes sous-jacents restent controversés. En utilisant les progrès récents dans les expériences in situ sur les lignes de faisceaux synchrotron, ce travail de doctorat vise à proposer une nouvelle compréhension des interactions entre la recristallisation de la ferrite et la formation de l'austénite et à développer un modèle prédictif pour la cinétique de formation de l'austénite. Le développement expérimental principal de cette thèse est une nouvelle technique d'analyse basée sur la diffraction des rayons X de haute énergie pour suivre in situ la recristallisation et les transformations de phase pendant la phase de recuit, y compris à des vitesses de chauffe élevées. Notre nouvelle méthode, appelée Isolated Diffraction Spot Tracking (IDST), est d'abord validée pour étudier la recristallisation sur des aciers ferritiques modèles. Ces mesures in situ sont complétées par des observations des microstructures après traitements interrompus en microscopie (optique, microscopie électronique à balayage et à transmission), et par des mesures de chimie locale (spectroscopie de rayons X à dispersion d'énergie et de dispersion en longueur d'onde). Nous reproduisons d'abord des expériences pour étudier l'influence de la vitesse de chauffe sur l'acier étudié pendant le recuit intercritique. Dans celles-ci, le chevauchement entre la recristallisation de la ferrite et la formation de l'austénite est régi par la vitesse de chauffe. Ensuite, nous avons conçu des expériences pour décorréler l'effet de la vitesse de chauffe et ce chevauchement. La vitesse de chauffe est fixée pour maintenir les mêmes conditions pour les mécanismes thermo-activés, mais le micro-alliage au niobium et le taux de laminage à froid plus faible retardent la recristallisation de la ferrite. Ces expériences montrent que la cinétique de transformation de l'austénite n'est pas contrôlée par la recristallisation, mais par la seule condition thermodynamique de l'interface de transformation et peut-être par la distance de diffusion dans les microstructures. Enfin, une analyse thermocinétique détaillée des mécanismes de formation de l'austénite au cours du recuit intercritique est proposée sur la base de simulations DICTRA/Thermo-Calc et de notre travail expérimental. L'effet des éléments d'alliage mineurs sur la cinétique de croissance de l'austénite est étudié et un modèle prédictif pour la formation de l'austénite pendant le recuit intercritique est développé. Finalement, ce travail montre l'absence d'effet significatif de la concomitance des mécanismes étudiés sur la cinétique de formation de l'austénite au cours de la chauffe. Nous montrons que la cinétique de formation de l'austénite est contrôlée par la diffusion. La différence de cinétique de formation de l'austénite au cours de la phase de maintien est expliquée par des considérations microstructurales, affectant les distances de diffusion<br>The formation of microstructures is a crucial step for steelmakers. In the case of DP steels, used for automotive construction, this formation takes place during intercritical annealing after cold-rolling. During this thermal treatment, after the heating step, the microstructure is made of recrystallized ferrite and austenite. During cooling, the austenite partially transforms into ferrite and then into martensite to reach the expected final ferrite/martensite microstructure. The austenitization step is therefore crucial for the manufacturers of these steels, to control the final phase fractions and sizes and, consequently, their mechanical properties. Numerous studies show that the heating rate controls the transformation kinetics and the morphology of the austenite ("necklace" or "banded"), but the underlying mechanisms remains a bone of contention. The overlap between ferrite recrystallization and austenite formation is often made responsible for these effects, through different mechanisms. Using recent advances in in situ experiments on synchrotron beamlines, this PhD proposes a new insight in the understanding of the interactions between ferrite recrystallization and austenite formation and develops a predictive model for the austenite formation kinetics. The main experimental development of this thesis is a new coupled time-resolved analysis technique, based on in situ High-Energy X-Ray Diffraction to track recrystallization and phase transformations during the annealing phase, including at high heating speeds. Our new method, called Isolated Diffraction Spot Tracking (IDST), is first validated to study recrystallization on model ferritic steels. These in situ measurements are supplemented by observations of microstructures after interrupted treatments in microscopy (optical, Scanning Electron Microscopy and Transmission Electron Microscopy), and from local chemistry measurements (Energy-Dispersive X-ray Spectroscopy and Wavelength Dispersion Spectroscopy)We first reproduce experiments to study the influence of the heating rate on the studied steel during the intercritical annealing. In such experiments, the overlap between ferrite recrystallization and austenite formation is governed by the heating rate. To go further, we designed experiments to decorrelate the effect of the heating rate and this overlap. During these, the heating rate is fixed to maintain the same conditions for thermo-activated mechanisms, but the niobium micro-alloying and lower cold-rolling ratio are used to delay ferrite recrystallization. These experiments show unambiguously that austenite transformation kinetics is not controlled by the recrystallization, but by the sole thermodynamic condition of interfaces and maybe by the diffusion distance in the microstructures. Finally, we propose a detailed thermo-kinetics analysis of the mechanisms of austenite formation during the intercritical annealing based on DICTRA/Thermo-Calc simulations and on our experimental work. The effect of minor alloying elements on the austenite growth kinetics is investigated. This work finally proposes new predictive models for austenite formation during the intercritical annealing. This PhD work finally shows no significant effect of the concomitance of the two studied mechanisms on the austenite formation kinetics along the heating stage. We demonstrate that the austenite formation kinetics is diffusion-controlled. The difference in austenite formation kinetics along the holding stage is explained by microstructural considerations, affecting the diffusion distances

The poems in this thesis are an exploration of how two worlds can exist at once. The first world is the physical world as we perceive it through our senses and experience it through living. It is a cyclical world that begins with childhood, and moves toward adulthood, parenthood and death. In this world we go about the act of living. Yet it is in the second world, a more metaphysical one, that we are most alive. We often gain our knowledge of this world through observing and experiencing the natural world. It is a place in which we discover our true selves. This world exists like the mythical ethers; its boundaries are unmarked and the journey takes us into places of light and dark, of sound and silence. It is the coexistence of these two worlds that I attempt to explore in my writing. To access this metaphysical world requires a certain sense of surrender. This can be difficult since it seems to be our species' natural tendency to try to tame or control our environment. Therefore, we must not assume the attitude of a conqueror of nature. We must assume instead the role as a student of nature. That means being truly attentive, finding stillness and quiet, and being willing to listen to the world around us. Secrets can be told in bird song or in the shadows of oaks. My love for nature and writing began at an early age. As a teen I fell in love with poetry. I discovered the poetry of the Victorians, Pre-Raphaelites and Romantics in old anthologies stored away in my grandparent's attic. In these dusty bound volumes with their frayed covers, I discovered the lyrical language of Browning, Tennyson, and Keats. Delving into them instilled in me the appreciation for the beauty of words playing upon each other. In later years, teachers and mentors, like Peggy and Frank Steele, introduced me to the poetry of William Stafford, Ted Kooser, and William Carlos Williams. I was drawn to the straightforward economical use of language by Stafford. His style explored the inner and outer world in language accessible to the average reader. Kooser also used accessible language to describe the human condition. His portraits and narratives instilled validity to my own sense of narrative found in many of my poems. Finally, my poet husband, Dorsey Grice, introduced me to the poetry of Mary Oliver. Her incredible attunement to and observations of nature left me humbled. Somewhere between those early discoveries of the traditional poetic canon and my studies of the modern/contemporary poets I have found my own voice emerge. The blending of the periods has created in me the tendency to write with an economy of language, combined with what I hope are lyrical, melodic lines that are imbued with a subtle sense of rhythm. In writing this creative thesis I have divided the poems into two sections. In general they explore how we relate within physical, social and spiritual contexts. The first section is entitled "A Woman You Might Know" and deals more with the human experience of raising children, finding and losing love, grieving for the ill and dying, and searching for wholeness. The second section is called "The Sound of Trees" and deals with observations within the natural world. It includes poems dealing with the changing of the seasons, farm life, observing wildlife, and the spiritual world. Although each is divided according to a general topic, they both hopefully convey the presence of a dual world in which we live every day and are occasionally allowed a glimpse into. It's a place where the voices of our ancestors gather round us to share their stories and teach us something of value about ourselves.

Mestrado em Engenharia Electronica e Telecomunicações<br>The way vineyards are organized brings up the need of removing the creepers that compete with vines for solar exposition and nutrients. Until now, the use of machines and herbicides has been the adopted solution but these techniques are aggressive for the environment and for this reason, new alternatives have to be found During the years several techniques have been developed to control herds, once these animals can replace the man in di erent tasks, for example, forest cleaning. This type of animals can reach places where machines can not and the present vegetation is part of their diet This dissertation builds up on the concept of virtual fence, extending it with a set of new functionalities that aim to adapt this type of technology to the characteristics of speci c crops, such as viticulture. The work carried out has focused both on the technological aspects, such as sensing and localization technologies, as well as on the economic aspects. In this latter case, the aim is to obtain a low cost system that can be massi ed.<br>O modo como as vinhas se encontram organizadas faz com que seja necessario remover as plantas mais rasteiras que competem com as videiras por exposição solar e nutrientes. Ate agora, o uso de maquinas e herbicidas tem sido a soluçao adoptada, mas estas tecnicas sao agressivas para o ambiente, sendo necessario encontrar outras alternativas. Ao longo dos anos varias tecnicas foram desenvolvidas para controlar rebanhos, uma vez que estes animais podem substituir o homem em diversas tarefas, como por exemplo, limpeza das florestas. Este tipo de animais consegue chegar a sítios onde algumas maquinas não conseguem e a vegetação presente faz parte da sua dieta. No âmbito desta dissertação tomou-se como base o conceito de cerca virtual, desenvolvendo-se um conjunto de novas funcionalidades que têm por objectivo adaptar este tipo de tecnologia as características de culturas especificas, como por exemplo a vitivinicultura. O trabalho realizado versou quer a vertente tecnológica, nomeadamente tecnologias de sensorização e localização, que a vertente económica, tendo-se neste caso por objetivo obter um sistema de baixo custo, que possa ser massificado.

Quality of maternal healthcare is one of the many pervasive public health challenges facing India. Maternal healthcare is defined as a fundamental human right and a crucial development issue by the UN, with direct links to the progress towards achieving the Sustainable Development Goals, especially reducing poverty (SDG1), ensuring healthy lives (SDG3) and achieving gender equality (SDG5). Whereas healthcare provision has traditionally been governed by a needs-based assessment approach founded on health resource utilisation data, social accountability is increasingly recognised and adopted by healthcare service providers as an approach that centres the perceptions and priorities of the recipient. There are many studies on the social accountability approach to maternal healthcare, but there is little current research on the link between aspirations and accountability in the context of low-resource maternal healthcare provision. Through the insights offered by social theorists including Bourdieu, Sen and Appadurai, this thesis examines a case study of the Hamara Swasthya Hamari Awaz campaign and the communications process it used to strengthen poor, rural Indian women’s voices and enable aspirations for better maternal healthcare. One semi-structured, in-depth interview and two secondary source interviews with campaign organisers, as well as 15 media texts and 121 social posts provided data about the campaign. The analysis revealed that the campaign used a social accountability approach, complemented by an operationalisation of the capacity to aspire approach, to: create a dialogue and information exchange with poor, rural Indian women; to amplify their voices about their priorities; and to support them to develop a capacity to aspire for, and realise that aspiration for, better maternal healthcare. By demonstrating the connection between the present and the future for these women, HSHA helped to form a platform for dialogue with traditional power-holders, leading to a sustainable aspiration-building framework for women’s empowerment on maternal health issues at the local, national and international levels.

Research exploring help-seeking for physical health and psychological difficulties is a well-established field. Historically, much of this research has focused on psychological and structural barriers to seeking help. In recent times, a new strand of help-seeking research has emerged that explores how some men successfully manage to seek help. Many of these studies have been informed by social constructionist and feminist perspectives, which view masculinities as multiple and enacted through a plethora of situations and interactions. This paper presents a critical review of these new developments in help-seeking research, centred around four main themes related to the psychological and social processes involved in how men sought help, to the resources they drew on and conflicts they experienced. These themes have been labelled: having ‘permission’, striving for a ‘manly’ expression of distress, reframing help-seeking and drawing upon experiences of ‘otherness’. While recognising the challenges of seeking help, it is hoped that by examining how men can manage to overcome these difficulties, this paper can prompt practitioners to reflect further on how to engage with men and masculinities.

Denna studie syftar till att beskriva patienters upplevelse av läkemedelsassisterad behandling för opiatberoende (LARO), även kallad underhållsbehandling. I studien undersöks hur upplevelsen av LARO är och hur den beskrivs utifrån två olika patientgrupper; de patienter med en mindre välfungerande behandling som dagligen går till mottagningen för att ta medicin övervakat och som lämnar urinprov två gånger i veckan, samt de patienter med en välfungerande behandling som går till mottagningen två gånger i veckan för att lämna urinprov men hämtar medicin på apoteket. I uppsatsen har sex patienter intervjuats om hur de upplever LARO. Uppsatsens resultat illustrerar bland annat upplevd brist på delaktighet och empowerment i behandlingen samt vikten av en god relation mellan patienter och personal på LARO-mottagningen. Studiens slutsats är att Patient empowerment bör vara grundstenen i all arbete med omvårdnad och behandling.<br>This study aims to describe patients' experiences of medication-assisted treatment for opioid dependence (LARO), also called maintenance therapy. The study examines how the patients experience LARO is and how the experience is percieved among the two patient groups: those patients with a less well functioning treatment that daily goes to the clinic to take medication supervised, and submit urine samples twice a week, as well as those patients with a functioning treatment that goes to the clinic twice a week to provide a urine sample but retrieves medicine from the pharmacy.In the paper, six patients were interviewed about how they experience LARO. Results of the thesis illustrate, among other things, the experienced lack of participation and empowerment in the treatment and the importance of a good relationship between patients and staff at LARO reception. The study concludes that patient empowerment should be the cornerstone of all the work with care and treatment.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on March 26, 2010). Thesis advisors: Dr. Trudy Lewis and Dr. Marly Swick. Vita. Includes bibliographical references.

This thesis explores nine individuals’ personal experiences with sexual assault and rape. The project provides a platform for voices that have been historically silenced, striving to empower and support survivors while raising awareness on the pertinent issues surrounding sexual assault and rape. By engaging in the tension between the individual narratives and the collective dimension of the experience of sexual assault, this thesis reframes the relationship between the personal and the political.

At Cape Gantheaume, Kangaroo Island (South Australia), adult male, lactating female and juvenile New Zealand (NZ) and Australian fur seals regularly return to the same colony, creating the potential for intra- and inter-specific foraging competition in nearby waters. I hypothesised that these demographic groups would exhibit distinct foraging strategies, which reduce competition and facilitate their coexistence. I analysed the diet of adult male, adult female and juvenile NZ fur seals and adult male Australian fur seals and studied the diving behaviour of adult male and lactating female NZ fur seals and the at-sea movements of juvenile, adult male and lactating female NZ fur seals. Female diet reflected that of a generalist predator, influenced by prey availability and their dependant pups� fasting abilities. In contrast, adult male NZ and Australian fur seals used larger and more energy-rich prey, most likely because they could more efficiently access and handle such prey. Juvenile fur seals primarily utilised small lantern fish, which occur south of the shelf break, in pelagic waters. Juveniles undertook the longest foraging trips and adult males conducted more lengthy trips than lactating females, which perform relatively brief trips in order to regularly nurse their pups. Unlike lactating females, some adult males appeared to rest underwater by performing dives that were characterised by a period of passive drifting through the water column. The large body sizes of adult males and lactating females facilitated the use of both benthic and pelagic habitats, but adult males dived deeper and for longer than lactating females, facilitating vertical separation of their foraging habitats. Spatial overlap in foraging habitats among the age/sex groups was minimal, because lactating females typically utilised continental shelf waters and males used deeper water over the shelf break, beyond female foraging grounds. Furthermore, juveniles used pelagic waters, up to 1000 km south of the regions used by lactating females and adult males. The age and sex groups in this study employed dramatically different strategies to maximise their survival and reproductive success. Their prey and foraging habitats are likely to be shaped by body size differences, which determine their different physiological constraints and metabolic requirements. I suggest that these physiological constraints and the lactation constraints on females are the primary factors that reduce competition, thereby facilitating niche partitioning.

<p>In this study the Stockholm Stock Exchange in Sweden is examined for herd behavior with a market wide approach. Three models, one created by Christie and Huang (1995) and the others created by Chang, Cheng and Khorana (1999), are applied to detect herd behavior from 1998 to 2009. Herd behavior is found in up-going market days, measuring on daily bases over the entire time frame. When breaking down the test period into annual sub-periods, herd behavior is evident in the bullish markets of 2005 and 2007. In days with the most extreme market movements herd behavior is found in large cap stocks but not in the small cap. The result indicates a tendency of an increasing level of herd behavior over the measured period, which can be attributed to the increased influence of institutional ownership. Moreover, the data was adjusted for thinly traded stocks and the result is contradictive to previous studies. The reduction of thinly traded stocks seems to have an increasing effect on the herd-measure, implying that the presence of thinly traded stocks puts a negative bias on the herd-measures.</p>

The veterinary input to many dairy farms is at best routine fertility visits confirmed to examination of the reproductive tract, and at worst occasional emergency calls. The Dairy Herd Health and Productivity Service (DHHPS) was established to provide the opportunity for veterinary surgeons to lead a multidisciplinary team which can monitor health, fertility and production and can plan remedial action, when necessary. Over a period of twenty years it has continued to identify infertility, mastitis and lameness as the main reason for the involuntary disposal of dairy cows, although on some farms BSE has been a major factor. The trend in the last few years has been for an increase in culling for reasons of disease rather than or age or yield. The average disease rates have remained consistently high with over 100 treatments per 100 cows each year. Infertility, mastitis and lameness are the most common disease problems on DHHPS farms. Blood profiling and condition scoring have demonstrated that at least a third of cows tested were mobilising excessive fat during the transition from the dry period to early lactation. The DHHPS found 34.3% of 9,235 dry cows, sampled 0-14 days before calving and 28 per cent of 20,502 cows between 5-40 days post calving, had raised BHB blood concentrations. 30.6 per cent of the same dry cows and 21.9 per cent of the early lactation animals had elevated NEFA results. Blood urea was measured to reflect the current protein intake and the protein/energy balance of the ration. 14 per cent of 9325 dry cows and 9.5 per cent of 20502 of early lactation cows had low urea N (<17 mmol/l). 25 per cent of the cows sampled between 5-40 post partum had blood urea nitrogen concentrations above 3.3mmol/l. Low magnesium levels were detected throughout the year. 9.2 per cent of 9235 dry cows and 7 per cent of 19,738 early lactation cows between 5-40 days calved had blood magnesium concentration <0.8 mmol/l.

According to the most common definition, self-translation refers to a phenomenon in which author and translator are the same individual. Self-translation has been practiced for centuries, and research on the practice has increased noticeably over the past 15 years. Yet, two main observations can be made with respect to academic interest pertaining to this phenomenon: first of all, to date, there exists no critical review of research conducted specifically on this topic; secondly, although certain scholars have noted that self-translation seems to be overlooked within translation studies texts in which translation is discussed as a general concept, little data has been provided to substantiate the extent to which this might be so. Therefore, in this thesis, I seek to identify which aspects of self-translation have been studied by self-translation scholars as well as what evidence there might be of self-translation in publications on translation as a broader topic. This investigation also reveals that which has not been studied, allowing the reasons for and implications of these gaps to be addressed. Ultimately, this project sheds light on the under-representation---or "invisibility"---of the self-translator and of self-translation within Translation Studies. In the first chapter, I conduct an etat des lieux of research on self-translation specifically, noting which aspects of self-translation have tended to be discussed and which have tended to be neglected. The second chapter involves analyzing the tables of contents and indices of encyclopedic publications as well as the argumentation of theoretical texts in order to ascertain whether there is evidence to substantiate that self-translation is under-represented. In the conclusion, I propose various reasons for which self-translation constitutes an important area of investigation within Translation Studies. 1An aided, simultaneous self-translation from the French version, with assistance from Joanne Desroches.

Thesis (Ocean. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, and Woods Hole Oceanographic Institution, 1994.<br>Includes bibliographical references.<br>by Peter Traykovski.<br>Ocean.E.

Into the Valley: Voices I Heard Along the Way contains a preface and a collection of five short stories. The preface discusses the use of voice as a technique to develop characters and create authenticity through elements such as sentence structure, diction, dialogue, and regional, cultural, and/or gender-specific affectations to make the words on the page become audible language in the mind of the reader. Each story is written with a unique voice that presents characters who struggle to come to terms with the truth and its various shades of reality.

<p> This dissertation explores the surprising phenomenon of listeners' unconsciously breathing in time to music, inspiring and expiring at select moments of specific works. When and how the experience of hearing music might produce stimulus-synchronous respiratory events is studied through Repeated Response Case Studies, gathering participants' respiratory sequences during repeated listenings to recorded music, and through Audience Response Experiments, responses for participants experiencing live music together in a concert hall. </p><p> Activity Analysis, a new statistical technique, supported the development and definition of discrete phase components of the breath cycle that come into coordination: the onsets of inspiration and expiration, the intervals of high flow during these two main phases, and the post-expiration pause. Alignment in these components across listenings illuminate when the naturalistic complex stimuli can attract or cue listener respiration events. </p><p> Four patterns of respiratory phase alignment are identified through detailed analysis of stimuli and responses. Participants inspired with the inspirations of vocalists and wind performers, suggesting embodied perception and imagined action may exert influence on their quiet breathing. Participants suppressed and delayed inspirations when the music was highly unpredictable, suggesting adaptation in aid of auditory attention. Similar behaviour occurred with sustained sounds of exceptional aesthetic value. Participants inspired with recurring motivic material and similar high salience events, as if marking them in recognition or amplifying their affective impact. And finally, participants occasionally breathed following structural endings, suggesting a sigh-like function of releasing the respiratory system from cortical control. </p><p> These instances of music-aligned respiratory phase alignment seemed to be stronger in participants who were typically active with heard music, but the impacts of training and expertise was not a simple condition for this behaviour. Contrasts between case study participants showed highly idiosyncratic patterns of respiratory alignment and differences in susceptibility along side moments of shared effect. In the audience experiments, alignment within phase components was measurable and significant, but rarely involved more than a quarter of participants in any given instance. These levels of concurrent activity in respiration underline the subtlety of this bodily response to music.</p><p>

Two data sets of first-parity classification records were analyzed to examine heterogeneity of variances for conformation in the U. S. Holstein population. Data set I included records for final score and linear descriptive traits on cows scored from 1983 through 1986. Results indicated a strong negative correlation (r = -.59) between within-herd standard deviation for final score and herd-mean final score. Regression analysis suggested a curvilinear decrease (concave up) in within-herd standard deviation for final score with increasing herd-mean final score. Within-herd standard deviations for linear descriptive traits demonstrated a linear decline with increases in herd-mean final score. Daughter contemporary deviation for final score was regressed on her sire’s Predicted Difference type within 25 mean/standard deviation subclasses. Response to selection was greatest in high-mean/variance herds and least in low-mean/variance herds. Restricted maximum likelihood estimates of sire and error variance were approximated within each of 5 herd-mean subclasses of the data. Regressions revealed environmental variance for final score decreased curvilinearly (concave up) with increasing herd-mean final score. Genetic variance declined linearly. Heritability demonstrated no significant trend. For most linear traits, environmental variance decreased linearly with increasing herd-mean final score. Linear decreases in genetic variance were noted for foot angle, udder depth and rump angle, Heritability had positive trends for body depth, angularity, rear udder height, udder support, and teat placement. Data set II included first-parity final scores on cows classified from 1967 to 1986. Relationships estimated between herd mean and within-herd variance for final score on recent data were confirmed. Positive trends over time were noted for: within-herd standard deviation for final score, the antagonistic relationship between herd mean and within-herd variance, the antagonistic relationship between average Predicted Difference type and within-herd variance, and average herd-mean Predicted Difference type. Results indicate selection for final score was occurring in the population. Differences in within-herd selection differentials accounted for 24% of the differences in within-herd variance for final score.<br>Ph. D.

Citizen participation includes those activities by citizens who are not public officials that are more or less intended to influence the actions taken by government (Verba & Nie, 1972). Citizen initiated contacts are one such form of participation. In 1999, the volume of complaint and service related calls received by the Department of Public Works and Engineering equaled almost 20 percent of the city's population. Via Houston's Customer Response Center, these contacts are logged in, directed to the appropriate department and incorporated into the department's infrastructure management system (IMS). The goal of the IMS is to provide a systems approach to making cost-effective decisions about the design, rehabilitation, construction, retrofitting, maintenance or abandonment of the city's infrastructure (Grigg, 1988). To date, the effectiveness of this program is perceived as less than ideal and the public is critical of the results (Graves, 2002). Residents express concerns that infrastructure projects are targeted towards business and industrial areas while neighborhood needs are being ignored. Politicians are concerned that projects are not equally distributed among the districts. Meanwhile, public works' staff are concerned because there isn't enough money to address citizen calls, business and industrial needs and political concerns in addition to the problems they have identified. The purpose of this research is twofold: to determine if citizen initiated contacts have been a significant factor in the selection of water and sewer projects and, to identify other factors that may play a role in the decision making process. This study is longitudinal in nature, covering the time period between 1992 and 1999. Univariate, bivariate and multivariate analysis were applied to the various data sets provided by the City of Houston. The results of the analysis supports the following: - Citizen contacts have been significant in determining the allocation of water and sewer CIP projects; however, that has not been consistent through the years. - Factors such as race, class, line type, material, size, age and location also factor into the decision making process.

This thesis aims to explore how conceptions of the black prophetic tradition, as discussed by thinkers Cornel West and George Shulman, might be expanded into the realm of African American musical traditions and genres. I argue that musical genres like the blues and hip-hop function as an affective discourse that aesthetically, politically and religiously function as sites of resistance to white supremacy and provide alternate pathways to liberation as compared to more canonical instantiations of the black prophetic. In particular I provide close readings of performances and art by Nina Simone and Kanye West.

Gerald Heard (1889-1971) was an influential figure among the intelligentsia of the 1930s, once described by E.M. Forster as “one of the most penetrating minds in England.” However, he remains an ill-defined footnote, a marginal figure whose influence and reputation, although acknowledged, remains unexamined. This dissertation examines his life and work, and considers the role which Heard, as a generaliser and public intellectual, played in the intellectual landscape of the 1930s. Central to Heard’s philosophy was a belief that society was in need of a spiritual and psychological force which could allow isolated individuals to participate in community with one another. Heard’s solution to bring about this evolution of consciousness would prove to be partly psychological, partly mystical and partly down to the product of a particular way of living. The first chapter outlines Heard’s philosophy in detail. Subsequent chapters are structured so as to provide a loose biographical chronology, each focussing on a different phase of Heard’s career and examining the development of his thought. Running throughout the dissertation is a consideration of Heard’s role as a public intellectual. It was as a popular ‘generaliser’ of thought that Heard found his public, and the limited degree of success he found as a man of action could be seen to be a natural limitation of the role he had constructed for himself. Chapter II focuses on Heard’s time as personal secretary to Sir Horace Plunkett, father of the Irish Co-Operative Movement, and how the ideals of this movement can be seen to inform his developing ideas of human community. Chapter III looks at Heard’s role as a broadcaster with the B.B.C., where he became a noted populariser of science, firmly establishing himself as a public figure and cultural authority. It is arguably this increased public profile which provided Heard with a ‘public’ to whom he could address his ideas. Chapter IV, drawing on archival material from Dartington Hall, considers Heard’s role as a lecturer at Dartington School, and more importantly his first experiment to establish a small ‘group’ for meditation in an attempt to discover the mystical and psychological basis for a co-operative society. Chapter V examines his career as an outspoken pacifist, where he would advance his arguments for a radical reorganisation of society as a practical solution to the question of peace and further attempt to become a man of action.

Améliorer la santé des vaches laitières en élevage agrobiologiques (AB) est bien souvent nécessaire, pour ces élevages ne répondant pas toujours aux principes de l’AB et aux attentes des consommateurs d’avoir un niveau de santé et bien-être animal élevé. Cette thèse explore des voies d’amélioration du conseil sanitaire en vue d'améliorer la santé animale dans ces élevages. Les résultats de nos travaux montrent que les vétérinaires ont le plus souvent un rôle de thérapeute dans les élevages laitiers AB. L'obtention d'un rôle de conseiller a été entravée par des spécificités liées à l’AB, telles que les différences entre éleveurs et vétérinaires dans les objectifs de gestion de la santé des animaux et les pratiques sanitaires. Une étude d'intervention a été effectuée pour tester un dispositif de conseil dans des élevages AB en France et en Suède, basé sur l’utilisation d’outils de surveillance et prévention de maladies de production. Le dispositif a été réalisé en utilisant une approche participative, impliquant l’éleveur et le conseiller ; la flexibilité de l’outil a permis de produire un protocole de surveillance adaptée à chaque élevage. Bien qu’aucun effet sur la santé du troupeau n’a été prouvé, le dispositif a été perçu pour contribuer à la santé du troupeau par ses utilisateurs. Il a rempli la plupart de ses fonctions prévues de surveillance et de prévention des maladies et a stimulé le dialogue entre éleveurs et conseillers. Des outils qui stimulent le dialogue et qui sont adaptables à chaque élevage sont une voie à suivre pour le développement du conseil en santé animale<br>Improving herd health on organic dairy farms is often needed, since organic dairy farms do not consistently meet the organic principles and consumers’ expectations of high animal health and welfare. This thesis explores ways to improve the pertinence of herd health advisory services in order to improve animal health on organic dairy farms. The results of our studies show that veterinarians mostoften have a role of therapist on organic dairy farms. Obtaining a more advisory role was hampered due to specificities of the organic sector, such as differences between farmers and veterinarians in animal health management objectives and practices. An intervention study was performed testing a Herd Health and Production Management (HHPM) program on organic dairy farms in France and Sweden, based on herd health monitoring and disease prevention activities. The program was built using a participatory approach, making farmer and advisor work together ; the adaptability of the program allowed to design farm specific herd health monitoring tools. Although no effecton herd health measured, the program was perceived to contribute to herd health by its users. The program fulfilled most of its intended functions in herd healthmonitoring and disease prevention and stimulated dialogue between farmers and their advisors. We consider that dialogue promoting and tools adaptable to farm specific situations are a possible way forward for the development of advisory services in animal health

<p> This study examines the use of performance ethnography as an advocacy tool for students with non-apparent disabilities at Mills College, a four-year institution in Oakland, California. The focus was on the sometimes challenging relationships between these students and their instructors. The methods in this study included analysis of a script that was created and performed by four women students with non-apparent disabilities and a series of interviews held pre-performance and then conducted at one and six months post-performance. The four student writer/performers were interviewed, as well as four faculty members who agreed to participate in the project. After analyzing the data I concluded that performance ethnography or ethnotheatre was a meaningful advocacy tool that deepened understanding and raised awareness and had the potential to improve student/faculty relationships. I recommend that such projects are encouraged in student social justice organizations and receive support from college administrations. For example, after a student performance such as <i>We Are Here to be Heard,</i> scheduling follow-up student/faculty workshops would enhance the learning experience for all concerned. Practitioners in disability services and student life who want to work with marginalized students would be well served to read some of the references cited in this study, and such practical guides for doing this kind of work such as Saldana's Ethnotheatre (2005). Based on my experience, staff considering this type of advocacy work with students with disabilities, apparent or non-apparent, also need to be mindful that embodied work may release strong emotions and topics such as stigma and identity threat may trigger painful memories. It is important that there is sufficient support to contain feelings that may arise, that boundaries are very clear and finally, the creative space needs to be a place of safety and security for all.</p>

The fields of translation and creative writing have long been seen as entirely distinct, with many writers drawing a distinction between types based on both the level of syntactic experimentation and the background of the translator. While most theorists would disagree, popular opinion (and the opinion of some poet/translators) seems to be that the two types of writing are differentiated by the amount of academic rigour and creative inspiration that goes into each: translation and creative writing are regarded as not merely different kinds of writing, but as involving different ways of writing. This thesis is an introspective exploration into the nature of translation, via a new translation of the Old English poem Beowulf. By translating Beowulf, reporting on that process, and comparing it with my creative work, this work provides an articulation of the creative process that views translation as a particular way of writing creatively that uses a source text as a narrative constraint. This work consists of two components: creative and critical. The creative portion is a translation of Beowulf which breaks the source poem up into numerous smaller pieces presented in a variety of voices, registers, and viewpoints. The critical portion is an examination of how that translation came about, and delineates the entire process, from initial preconceptions to final finished work. It explores the issues of how to domesticate or foreignise a poem so removed from modern England both culturally and temporally, what level of knowledge a translator can or should expect of her readers, and where knowledge and authority can be situated in a translation. The methodology of the critical portion is an analysis of Beowulf's history as a source text and as a translation, a study of translation theories, and an experiential analysis of the process of producing a new translation of Beowulf.

The purpose of this study is to examine the problems that pregnant teenagers encounter at school and at home while they are trying to complete their high school education. Data were collected by in-depth interviews. Twenty pregnant adolescents, who were between the ages of 15 through 18, and were participants in a special teen pregnancy program were interviewed. The major findings in this study included the respondents': 1) unstable family life histories, 2) denial that they were pregnant, 3) need for self-identity as an adult, 4) conflict with parents and 5) motivation to complete their high school education. This study points to the need for more research on the problems that pregnant adolescents encounter in their everyday lives.

El sector porquí Espanyol ha sofert recentment profuns canvis degut bàsicament a<br/>l'augment de la competència i al procés de globalització econòmica. Ademes, els<br/>avenços tecnológicos i el grau creixent d'especialització en el sector afavoreixen el<br/>desenvolupament i l'adopció de eienes avançades per a la pressa de decisions. En<br/>aquest context, l'objectiu d'aquesta Tesi ha estat formular i implementar un model<br/>dinàmic estocàstic del comportament productiu d'un remat de truges, basat en<br/>processos de decisió Markovians i capaç d'ésser utilitzat en condicions reals. La<br/>finalitat del model és representar alternatives de maneig reproductiu i de reposició en<br/>explotacins porcines per assistir als grangers, tècnics i gerents en la pressa de<br/>decisions en granja.<br/>El model de decisió semi-Markovià i el Markovià que s'en deriva del primer han<br/>demostrat ser models útils per la representació de les estratègies productives de<br/>maneig reproductiu i de la reposició. La disponibilitat de dades de camp de granges<br/>individuals ha permès la validació del model en situacions reals. La validació ha servit<br/>també per mostrar com el model no pot ser aplicat indiscriminadament a qualsevol<br/>granja, prèviament s'ha d'assegurar l'ajust del model a les condicions concretes de<br/>cada explotació. També s'ha ficat de manifest que quan el model s'utilitza per a<br/>calcular l'estructura de la població a l'equilibri no és necessari que la matriu de<br/>transició representi el pas de temps constant, la qual cosa ha permès treballar amb<br/>transicions associades als estats biològics que són més fàcils d'estimar (embedded<br/>Markov process), ademes, proporcionen estalvis computacionals que permeten una<br/>avaluado més ràpida d'alternatives de maneig reproductiu i la implementació<br/>d'algorismes d'optimització pel problema de la reposició més eficientes.<br/>La implementació del model de decisió semi-Markovià dins d'un sistema d'ajut a la<br/>pressa de decisions (DSS: Decision Support Systems) ha mostrat l'ús potencial del<br/>model en granja. El desenvolupament del DSS ha facilitat la disponibilitat d'un model<br/>complex com el presentat a potencials usuaris menys especialitzats. El DSS permet al<br/>granger avaluar a peu de granja diferentes alternatives productives, analitzar la<br/>sensibilitat dels paràmetres que consideri crítics i optimitzar la política de reposició.<br/>Ademes, la integració del DSS en un sistema de gestió informatitzat (BDporc®2)<br/>facilita la difusió del DSS en empreses de producció porcina i també l'obtenció de<br/>noves variables com el número de serveis por monta, la detecció de zels, la detecció<br/>de la gestació, instalacions, etc, que poden ajudar a incrementar la precisió dels<br/>resultats. El disseny sofisticat del interface del DSS ha millorat la interpretació dels<br/>resultats del model que no sempre és inmediata. La incorporació de l'anàlisi de<br/>sensibilitat permet estudiar i profunditzar en els components crítics del model que<br/>sovint resulta més important que l'obtenció d'un resultat precis. Finalment, el model de<br/>remat formulat de forma flexible, és capaç d'adaptar-se a diferents propòsits amb<br/>canvis mínims, la qual cosa contribueix a una millor comprensió dels efectes de<br/>diferentes alternatives de maneig reproductiu sobre la millora de la eficiència<br/>econòmica de tot el sistema productiu.<br>El sector porcino en España ha sufrido recientemente profundos cambios debido<br/>básicamente al aumento de la competencia y al proceso de globalización económica.<br/>Además, los avances tecnológicos y el creciente grado de especialización en el sector<br/>favorecen el desarrollo y la adopción de herramientas avanzadas para la toma de<br/>decisiones. En este contexto, el objetivo de esta Tesis es presentar la formulación e<br/>¡mplementadón de un modelo dinámico estocástico del comportamiento productivo de<br/>un rebaño de cerdas, basado en procesos de decisión Markovianos y capaz de ser<br/>usado en condiciones reales. La finalidad del modelo es representar alternativas de<br/>manejo reproductivo y de reposición en explotacines porcinas para asistir a granjeros,<br/>técnicos y gerentes en la toma de decisiones en granja.<br/>El modelo de decisión semi-Markovianos y el Markoviano que deriva del primero han<br/>demostrado ser modelos útiles en la representación de las estrategias productivas de<br/>manejo reproductivo y de la reposición. La disponibilidad de datos de campo de<br/>granjas individuales ha permitido la validación del modelo en situaciones reales. La<br/>validación ha servido también para mostrar como el modelo no puede ser aplicado<br/>indiscriminadamente en cualquier granja, previamente se asegurar el ajuste del<br/>modelo a las condiciones concretas de cada explotación. También se ha puesto de<br/>manifiesto que cuando el modelo se utiliza para calcular la estructura de la población<br/>en equilibrio no es necesario que la matriz de transición represente de paso de tiempo<br/>constante, con lo cual ha sido posible trabajar con transiciones asociadas a los<br/>estados biológicas que son más fáciles estimar (embedded Markov process), además,<br/>proporcionan ahorros computacionales que permiten una evaluación más rápida de<br/>alternativas de manejo reproductivo y la implementación de algoritmos de optimización<br/>para el problema de la reposición más eficientes.<br/>La implementación del modelo de decisión semi-Markoviano dentro de un sistema de<br/>ayuda a la toma de decisiones (DSS: Decision Support Systems) ha mostrado el uso<br/>potencial del modelo en granja. El desarrollo del DSS ha facilitado la disponibilidad de<br/>un modelo complejo como el presentado a potenciales usuarios menos especializados.<br/>El DSS permite al granjero evaluar a pie de granja diferntes alternativas productivas,<br/>analizar la sensibilidad de los parámetros que considere críticos y optimiza la política<br/>de reposición. Además, la integración del DSS en un sistema de gestión informatizado<br/>(BDporc®3) facilita la difusión del DSS en empresas de producción porcina y también<br/>la obtención de nuevas variables como el número de servicios por monta, la detección<br/>de celos, la detección de la gestación, instalaciones, etc, que pueden ayudar a<br/>incrementar la precisión de los resultados. El diseño sofisticados del interface del DSS<br/>ha mejorado la interpretación de los resultados que no siempre es inmediata. El<br/>análisis de sensibilidad incorporado permite estudiar y profundizar en los componentes<br/>críticos del modelo que a menudo resulta más importante que el disponer de un<br/>resultado preciso. Finalmente, el modelo de rebaño formulado de forma flexible, es<br/>capaz de adaptarse a distintos propósitos con cambios mínimos, lo que redunda en<br/>una mejor compresión de los efectos de diferentes alternativas de manejo reproductivo<br/>a fin de mejorar la eficiencia económica de todo el sistema productivo.<br>Spanish pig sector has gone through a deep change during recent times, that is due<br/>basically to the increase in competitiveness and the globalisation process of the<br/>economics. Furthermore, technological advances and the increasing degree of<br/>specialisation have maden possible the development and adoption of advanced tools<br/>for decision support. In this context, the objective of this Thesis has been to formulate<br/>and implement a dynamic estochastic model representing the productive behaviour of<br/>a sow herd, based on Markov decision processes. The model was aimed to be used in<br/>field condicions to analyse different management alternatives on reproduction and<br/>replacement, supporting farm managers in the decision-making process.<br/>The semi-Markovià decision model and the derived Markov decision model (embedded<br/>Markov process) have demonstrated to be useful in the representation of management<br/>alternatives on reproduction and replacement. The availability of data from individual<br/>farms has allowed the validation of the model in real situations. The validation also has<br/>served to show how the model can not be applied indiscriminately on any farm.<br/>Previously, it has been required to assess the fit of the model in specific farm<br/>conditions. Also, it is shown that when the model has been used to calculate the<br/>population structure at equilibrium was not necessary a transition matrix being time<br/>step constant. Instead have been possible to consider transitions associated to<br/>biological states that are easier to estimate, more precise and provided computational<br/>time savings. Hence the model, as it was formulated, allowed a faster evaluation of<br/>management alternatives on reproduction and an efficient impleemntation of algorithms<br/>to optimise replacement policies.<br/>The implementation of the semi-Markov model into a DSS (DSS: Decision Support<br/>Systems) has shown the potential on-farm use of the model. The development of the<br/>DSS makes easier the availability of complex models to less specialised users. The<br/>DSS allows the farm manager to evaluate on-farm different management alternatives<br/>on reproduction and optimise replacement decisions. Moreover, the integration of the<br/>DSS in a management information system (BDporc®1) makes easier the spreading of it<br/>over swine enterprises, as well the obtention of new variables like the number of<br/>services by mating, heat detections, pregnancy detection, facilities, etc, can help to<br/>increment model precision. The sophisticated dessign of the DSS interface has<br/>improved the interpretation of the model results, that not always is right direct. The<br/>addition of sensitivity análisis capability provided insight about the impact of changes in<br/>critical components of the model, that quite often result in a more interest than a single<br/>precise result. Finally, the sow herd model formulated in a flexible way, was able to be<br/>adapted to différents goals with minimum changes, thus it contribute to improve the<br/>knowledge about the effect of different management alternatives on overall economic<br/>efficiency of the system.

The effect of composite and descriptive linear type traits on Functional Herd Life in Holstein cows was studied by means of Survival Analysis (Ducrocq and Solkner, 1998a). The original data set contained 331,105 lifetime records from the Programme d'Analyse des Troupeaux Laitiers du Quebec, from January 1980 to March 1995. Only 191,167 records (or cows) had type information. Mixed Weibull models were fitted to analyse the data; the probability of being culled (hazard) was defined as a product of a baseline Weibull hazard function and explanatory variables. The heritability estimates for Functional Herd Life were 0.07 in the log scale and 0.15 in the original scale. Sire Estimated Transmitting Ability for FHL, expressed as relative culling rate, ranged from 0.6 to 1.4 for all models. Solutions for fixed effects (all significant) indicated a higher probability of being culled for primiparous cows calving at older ages, for cows producing below herd average, for first lactation cows in the first and last stage of lactation and for older cows at the end of lactation. The risk of being culled did not change for cows in herds decreasing or increasing in size. Cows classified with a high score for Final Score were less likely to be culled; Final Score seems to be an important selection criteria among Quebec producers. Feet and Legs, Rump and Mammary System are traits that producers consider in their culling policies; cows classified with a high score had more chance of surviving. Among the linear type traits, the 5 traits with the highest impact on productive life, were Rear Attachment Height, Fore Attachment, Bone Quality, Stature and Fore Teat Placement; Quebec producers seem to consider these traits when they make their culling decisions.

Human papillomavirus (HPV) has a high prevalence among the population, and brings an enormous health impact and burden to the public. Vaccines have been developed in recent years, and their efficacy has been noted in many studies. Although there is much theoretical research conducted worldwide on the indirect protective effect of HPV vaccines to the unvaccinated population, convincing evidence on real world settings is still to be found. This systematic review recruits studies from two databases, PubMed and MEDLINE ovidSP and is intended to examine herd protection on community levels. 5 studies are included and the conclusion suggests that the herd protection is most significant among the sexually active young population, whereas it doesn’t seem to benefit people of older age. Therefore, follow up studies in the future are still needed to evaluate the herd immunity among the old age groups.<br>published_or_final_version<br>Public Health<br>Master<br>Master of Public Health

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR<br>PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO<br>PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTITUIÇÕES COMUNITÁRIAS DE ENSINO PARTICULARES<br>A presente tese é composta por três pesquisas. A primeira pesquisa buscou averiguar o relacionamento entre o FXvol e os retornos futuros da taxa cambial e do índice de mercado de ações, dado que o índice de volatilidade FXvol é visto como um termômetro da incerteza do investidor um período a frente. Investiga-se então a relação contemporânea entre o FXvol, a Ptax e o Ibovespa, bem como a capacidade do FXvol de captar a possível relação entre o nível de incerteza presente no mercado e as variações relativas futuras da taxa de câmbio e do índice de ações. A segunda pesquisa comparou os modelos GARCH tradicionais e o modelo GARCH com troca de regimes no que tange seu poder de previsão da volatilidade cambial. Buscou-se comparar o desempenho de cada um dos modelos em uma situação real de utilização, no caso, no cálculo do Valor em Risco de uma carteira cambial. A terceira pesquisa buscou identificar a existência do efeito manada no mercado brasileiro e compreender a influência do câmbio nesse efeito, devido à importância do mercado cambial para a realidade brasileira. A metodologia compreendeu dois passos, em um primeiro momento buscou-se analisar a média do efeito através de regressões tradicionais e num segundo momento estudar a variação do efeito ao longo do tempo através do método do Filtro de Kalman.<br>The present thesis consists of three researches. The first research sought to ascertain the relationship between FXvol and future exchange rate and stock market index returns as the FXvol volatility index is viewed as a thermometer of investor uncertainty for a period ahead. The contemporary relationship between FXvol, Ptax and Ibovespa, as well as the ability of FXvol to capture the possible relationship between the level of uncertainty present in the market and the relative future return of the exchange rate and the stock index. The second research compared the traditional GARCH models and the GARCH model with regime changes regarding its power to predict the exchange rate volatility. We attempted to compare the performance of each of the models in a real situation of use, in this case, in the calculation of the Value at Risk of an exchange portfolio. The third research sought to identify the existence of the herd effect in the Brazilian market and to understand the influence of the exchange rate in this effect, due to the importance of the exchange market for the Brazilian market. The methodology comprised two steps, initially attempting to analyze the mean of the effect through regressions and in a second moment to study the variation of the effect over time through the Kalman Filter method.

The main objective of this work was to undertake analyses which would lead to an improvement in the accuracy of production and type breeding value predictions for Holstein-Friesian dairy cattle and to investigate the relationship between production and type traits and herd life. Production records were obtained from the National Milk Records files and linear type records from the Holstein Friesian Society. An animal model estimation of heterosis and recombination loss between North American Holstein and European cattle for first lactation milk, fat and protein yield showed that the omission of these effects in breeding value prediction would bias the results. Including both these effects in the breeding value estimation increased the predicated sire proof for fat plus protein yield of a typical F1 Holstein X Friessian sire by 3kg. An analysis of approximately 275 000 first lactation records and the 2<SUP>nd</SUP> to 5<SUP>th</SUP> lactation records of survivors found the regression coefficients of yield in lactations 1 to 5 on heterosis and recombination loss to be fairly consistent over lactations. After fitting first lactation yield in the model and compared to a pure Friesian, there is an increased chance of survival to third lactation of 3.6% for a pure Holstein, 3.8% for an F1 and an F2, and 2.4% for a Friesian backcross. In the investigation of herd life, defined as the completion of a specified number of lactations, in relation to linear type traits and production, results were not completely consistent either over lactations or over different subsets of the population. In general, there was a significant positive association between survival and angularity, fore udder attachment and udder depth and a negative association with chest width, rump width and teat length. Regressions on yield were positive, while those on fat and protein content were usually negative.

Thesis (B.S.)--California Polytechnic State University, 2009.<br>Project advisor: Bruce Golden. Title from PDF title page; viewed on Jan. 21, 2010. Includes bibliographical references. Also available on microfiche.

Since its appearance, Porcine Reproductive and Respiratory Syndrome (PRRS) has devastated the worldwide swine industry with tremendous economic losses. The high heterogeneity among PRRSV isolates is likely to be the main obstacle to effective control of PRRSV infection using current commercial vaccines, since the immunity induced by one strain may be only partial against a different strain, even within the same genotype. The purposes of my research were to better understand the epidemiology and the diffusion of PRRSV infection in two positive breeding herds and to evaluate the effectiveness and the critical points of the gilts acclimatization programmes, using adequate diagnostic tools and phylogenetic analysis of PRRSV isolates. I also took part in the development of a quantitative real time polymerase chain reaction for PRRSV diagnosis in serum and tissues and evaluated the effectiveness of vaccination against Porcine Circovirus type-2 (PCV2) in a farm coinfected with both PRRSV and PCV2.<br>La Sindrome Riproduttiva e Respiratoria del Suino (PRRS) causa tuttora ingenti perdite economiche nell’intera filiera suinicola mondiale. L’agente eziologico è un virus a RNA (PRRSV) della famiglia Arteriviridae, responsabile di una malattia respiratoria nei suini all’ingrasso, con ridotta crescita ponderale e aumentata mortalità, e di una sindrome riproduttiva nella scrofa, con maggior incidenza di aborti e minor numero di suinetti nati vivi. Data l’eterogeneità dei ceppi circolanti e la scarsa cross-protezione tra ceppi eterologhi, i vaccini attualmente disponibili non sono efficaci in tutte le realtà di campo. Per questo l’adozione di rigide misure di biosicurezza e l’acclimatamento dei riproduttori sono comunemente considerati gli strumenti più efficaci per il controllo della PRRS negli allevamenti da riproduzione (3). L’obiettivo è quello di impedire l’entrata di un nuovo ceppo virale dall’esterno, preservare la stabilità aziendale limitando la circolazione virale nell’azienda e promuovere l’instaurarsi di una immunità protettiva nei confronti del ceppo di campo. È quindi chiaro che il monitoraggio dell’infezione in azienda, dell’immunità degli animali da rimonta e dei ceppi virali circolanti riveste un’importanza fondamentale per lo sviluppo di nuove strategie di controllo e per il miglioramento di quelle esistenti. In tale contesto si è inserito il mio progetto di ricerca. In questi tre anni ho sviluppato diverse tematiche legate al controllo della PRRS in due allevamenti da riproduzione, situati in Veneto e in Friuli Venezia Giulia. Ho inoltre condotto un’infezione sperimentale con PRRSV nell’azienda dello studio A per validare una PCR quantitativa a partire da diverse matrici biologiche ed uno studio sull’efficacia di un vaccino commerciale contro Porcine Circovirus tipo-2 (PCV2) in un allevamento affetto sia da PRRSV che da PCV2.