Yes / Medical Research Council

The reliability of genetic evaluations across separate management units (e.g. flocks) depends on the extent of genetic links or connections among animals in these units. Where poor connectedness exists, comparisons of estimated breeding values (EBV) across units may be biased. The objectives of this study were to identify breeding strategies to increase connectedness among units, to evaluate statistics that may reflect the reduction in bias as connectedness increases in such strategies, and to assess levels of connectedness in Suffolk and Targhee flocks participating in the National Sheep Improvement Program. Expectations of bias when production units have different genetic means were derived for a simple sire model. These expectations were applied to data involving two flocks of animals with three different types of connections: sharing of a common reference sire or use of either a full- or half-sibling sire in each flock. Bias decreased as numbers of progeny in each flock increased for all methods. Linking through a reference sire was most effective and was the only method that eliminated bias as progeny numbers became infinite. Pedigree and performance data on a single trait with heritability 0.25 were then simulated for 15 flocks with 40 to 140 ewes per flock. Each flock was simulated with a different founder genetic mean to introduce bias into the genetic evaluation. Flocks participated in sire referencing schemes by artificial insemination, with varying levels of participation, or by natural service. With sire referencing genetic gain was higher and inbreeding was lower than without, and bias was rapidly reduced to near-zero levels. Discontinuing the schemes led to lower genetic gain, but bias was not reintroduced. The prediction error correlation of flock genetic means was proposed as a connectedness measure because it was strongly associated with bias. Benchmarks of 0.05 and 0.10 for "good" and "superior" connectedness were established. Targhee flocks have increased connectedness across the breed by actively exchanging rams over 15 yr. In the Suffolk breed, connectedness has only improved within segregated clusters of flocks. Suffolk breeders need to engage in active ram exchange to decrease risk of biased across-flock EBV comparisons. / Ph. D.

A Ecocardiografia continua sendo a técnica de captura de imagens mais promissora, não-invasiva, sem radiação ionizante e de baixo custo para avaliação de condições cardíacas. Porém, é afetada consideravelmente por ruídos do tipo speckle, que são difíceis de serem filtrados. Por isso fez-se necessário fazer a escolha certa entre filtragem e segmentador para a obtenção de resultados melhores na segmentação de estruturas. O objetivo dessa pesquisa foi estudar essa combinação entre filtro e segmentador. Para isso, foi desenvolvido um sistema segmentador, a fim de sistematizar essa avaliação. Foram implementados dois filtros para atenuar o efeito do ruído speckle - Linear Scaling Mean Variance (LSMV) e o filtro de Chitwong - testados em imagens simuladas. Foram simuladas 60 imagens com 300 por 300 pixels, 3 modelos, 4 espessuras e 5 níveis de contrastes diferentes, todas com ruído speckle. Além disso, foram feitos testes com a combinação de filtros. Logo após, foi implementado um algoritmo de conectividade Fuzzy para fazer a segmentação e um sistema avaliador, seguindo os critérios descritos por Loizou, que faz a contagem de verdadeiro-positivos (VP) e falso-positivos (FP). Foi verificado que o filtro LSMV é a melhor opção para segmentação por conectividade Fuzzy. Foram obtidas taxas de VP e FP na ordem de 95% e 5%, respectivamente, e acurácia em torno de 95%. Para imagens ruidosas com alto contraste, aplicando a segmentação sem filtragem, a acurácia obtida foi na ordem de 60%. / The echocardiography is the imaging technique that remains most promising, noninvasive, no ionizing radiation and inexpensive to assess heart conditions. On the other hand, is considerably affected by noises, such as speckle, that are very difficult to be filtered. That is why it is necessary to make the right choice of filter and segmentation method to obtain the best results on image segmentation. The goal was evaluate this filter and segmentation method combination. For that, it was developed a segmentation system, to help the assessment. Two filters were implemented to mitigate the effect of speckle noise Linear Scaling Mean Variance (LSMV) and the filter presented by Chitwong - to be tested in simulated images. We simulated 60 images, with size 300 by 300 pixels, 3 models, 4 thicknesses and 5 different levels of contrast, all with speckle noise. In addition, tests were made with a combination of filters. Furthermore, it was implemented a Fuzzy Connectedness algorithm and an evaluation system, following the criteria described by Loizou, which makes the true positives (TP) and false positives (FP) counting. It was found that the LSMV filter is the best option for Fuzzy Connectedness. We obtained rates of TP and FP of 95% and 5% using LSMV, and accuracy of 95%. Using high contrast noisy images, without filtering, we obtained the accuracy in order of 60%.

A Ecocardiografia continua sendo a técnica de captura de imagens mais promissora, não-invasiva, sem radiação ionizante e de baixo custo para avaliação de condições cardíacas. Porém, é afetada consideravelmente por ruídos do tipo speckle, que são difíceis de serem filtrados. Por isso fez-se necessário fazer a escolha certa entre filtragem e segmentador para a obtenção de resultados melhores na segmentação de estruturas. O objetivo dessa pesquisa foi estudar essa combinação entre filtro e segmentador. Para isso, foi desenvolvido um sistema segmentador, a fim de sistematizar essa avaliação. Foram implementados dois filtros para atenuar o efeito do ruído speckle - Linear Scaling Mean Variance (LSMV) e o filtro de Chitwong - testados em imagens simuladas. Foram simuladas 60 imagens com 300 por 300 pixels, 3 modelos, 4 espessuras e 5 níveis de contrastes diferentes, todas com ruído speckle. Além disso, foram feitos testes com a combinação de filtros. Logo após, foi implementado um algoritmo de conectividade Fuzzy para fazer a segmentação e um sistema avaliador, seguindo os critérios descritos por Loizou, que faz a contagem de verdadeiro-positivos (VP) e falso-positivos (FP). Foi verificado que o filtro LSMV é a melhor opção para segmentação por conectividade Fuzzy. Foram obtidas taxas de VP e FP na ordem de 95% e 5%, respectivamente, e acurácia em torno de 95%. Para imagens ruidosas com alto contraste, aplicando a segmentação sem filtragem, a acurácia obtida foi na ordem de 60%. / The echocardiography is the imaging technique that remains most promising, noninvasive, no ionizing radiation and inexpensive to assess heart conditions. On the other hand, is considerably affected by noises, such as speckle, that are very difficult to be filtered. That is why it is necessary to make the right choice of filter and segmentation method to obtain the best results on image segmentation. The goal was evaluate this filter and segmentation method combination. For that, it was developed a segmentation system, to help the assessment. Two filters were implemented to mitigate the effect of speckle noise Linear Scaling Mean Variance (LSMV) and the filter presented by Chitwong - to be tested in simulated images. We simulated 60 images, with size 300 by 300 pixels, 3 models, 4 thicknesses and 5 different levels of contrast, all with speckle noise. In addition, tests were made with a combination of filters. Furthermore, it was implemented a Fuzzy Connectedness algorithm and an evaluation system, following the criteria described by Loizou, which makes the true positives (TP) and false positives (FP) counting. It was found that the LSMV filter is the best option for Fuzzy Connectedness. We obtained rates of TP and FP of 95% and 5% using LSMV, and accuracy of 95%. Using high contrast noisy images, without filtering, we obtained the accuracy in order of 60%.

Barrier trees are a convenient way of representing the structure of complex combinatorial landscapes over graphs. Here we generalize the concept of barrier trees to landscapes defined over general multi-parent search operators based on a suitable notion of topological connectedness that depends explicitly on the search operator. We show that in the case of recombination spaces, path-connectedness coincides with connectedness as defined by the mutation operator alone. In contrast, topological connectedness is more general and depends on the details of the recombination operators as well. Barrier trees can be meaningfully defined for both concepts of connectedness.

Background Long life does not inevitably mean more healthy years; older women have an increased risk of disabilities, diseases and adverse life events. Nevertheless, many older women experience health. This may be explained by possessing resources that promote health, despite adversities. Inner strength is seen as a resource as such. In this thesis inner strength is interpreted according to a theoretical model where inner strength comprises four interrelated and interacting dimensions: connectedness, creativity, flexibility and firmness, and being rated by the Inner Strength Scale (ISS). Aim and methods The overall purpose of this thesis was to explore inner strength as a health resource among older women. In study I six focus group interviews were performed with older women (66-84 years; n = 29) and the interviews were analysed by a concept driven approach and by means of qualitative content analysis. Studies II–IV had a quantitative, cross-sectional design. A questionnaire was sent to all older women (65 years and older) living in Åland, an autonomous island community in the Baltic Sea, and 1555 (57%) women responded. The data was analysed using descriptive and inferential statistics. Results In study I, exploring how inner strength and its dimensions can be identified in narratives of older women, connectedness was interpreted as a striving to be in communion, creativity as the ability to make the best of the situation, firmness as having a spirit of determination – “it is all up to you”, and flexibility as a balancing act. The results of study II showed that strong inner strength was associated with better mental health, but not physical health. In exploring factors associated with health-related quality of life, fewer symptoms of depressive disorders was the strongest explanatory variable, and together with not feeling lonely associated with better both physical health and mental health. Better physical health was also explained by not having a diagnosed disease, being of lower age and the opportunity to engage in meaningful leisure activities. Better mental health was additionally explained by having enough money for personal needs. In study III the result showed that non-depressed women were likely to have a strong inner strength, as well as never or seldom feeling lonely, taking fewer prescribed drugs, feeling needed and having the opportunity to engage in meaningful leisure activities. In study IV poorer mental health was associated with weaker inner strength in total, and in all four dimensions of inner strength. Symptoms of depressive disorders and feeling lonely were related to lower scores in three of the dimensions (except firmness and creativity, respectively) and poorer physical health was associated with lower scores in two of the dimensions (firmness and flexibility). Some other health threats were significantly associated with only one of the dimensions (connectedness or creativity), and others were not significantly associated at all. Conclusion The results add nuance to the notion of inner strength and deepen empirical knowledge about the phenomenon. It is elucidated that the ISS can be used not only to rate inner strength but also to offer guidance as to the areas (i.e. dimensions) in which interventions may be profitable. It is further shown that inner strengths can be identified in narratives of older women. Mental ill health has shown to have overall the strongest association with weakened inner strength among community-dwelling older women. The causality can, though, not be studied due to the cross-sectional design; therefore, longitudinal studies are recommended. Notwithstanding that limitation, the findings can be used as a knowledge base in further research within this field.

Proximal and Distal Indirect Influences on Adolescent Sexual Activity and Post Risky Sexual Behaviors INTRODUCTION: Prior literature has revealed a correlation between adolescent sexual debut and parenting behaviors. However, most existing studies has only focused on parental monitoring and control. This limitation, in addition to small, cross-sectional studies, has resulted in inconsistent and limited findings. These gaps are addressed in this present paper by investigating how family connectedness contributes to the age of sexual debut. It is hypothesized that adolescents who are 13 years of age and have a lack of family connectedness engage in high-risk behaviors sooner than their 13-year-old peers with greater family connectedness. METHODS: Data were drawn from the 1997 National Longitudinal Survey of Youth. This paper focused on adolescents born in the year 1983 who had no sexual debut at baseline. Those selected were initially interviewed for baseline family connectedness and prospectively followed up to adulthood. Family connectedness was measured using five aspects: shared activities, parent-adolescent communication, parent admiration, parental support and the presence of family dinners. SAS 9.4 was used to perform survival analyses to examine the rate of teenage sexual debut by family connectedness. RESULTS: Findings suggest that family connectedness, specifically weekly family dinners and parent-child communication were significant familial factors that delayed adolescent sexual behavior. The hazards ratio of having an adolescent sexual debut at any time for an individual who had family activity at least once a week was 0.91 (95CI: 0.74, 1.14), having weekly family dinner (HR 0.70; 95CI: 0.53, 0.93), communication with parents (HR 0.78; 95CI: 0.68, 0.91), perceived parental support (HR 1.04; 95CI:0.91, 1.02), think highly of parents (HR 1.08; 95CI 0.93, 1.25). CONCLUSION: This study attempted to observe other factors outside of the parental monitor and control that could contribute to adolescent sexual activity. However, family connectedness was found to be a protective factor only among family weekly dinner and parent-child communitcation. Public health policy and interventions aimed at family connectedness alone will unlikely influence adolescent sexual behaviors. Therefore, other factors along with family connectedness should be further assessed to discover its true correlation on sexual debut.

The purpose of this qualitative descriptive study was to develop a greater clarity of how HIV infected individuals live and work within the sphere of HIV infection as represented through unsolicited, personal narratives posted on blogs. Existing, single author, personal blogs were identified via a search engine. Blogs were defined as the blog author's postings and all responses, whether written by the blog author or a reader respondent. Inclusion and exclusion criteria were developed to respect indicators of bloggers' intentions for privacy, e.g., blogs which required a password were excluded. A total of 14 blogs met inclusion criteria. Actions to promote validity focused on the areas of credibility, authenticity, criticality, and integrity. Throughout the blogs, online social connectedness formed the context for expression of the four themes identified to describe the experiences of the bloggers and their readers living with HIV infection. Suffering was the human experience of stigma related to living with HIV infection. This was primarily manifested in either self-imposed isolation or isolation resulting from rejection by others. Relationships addressed both the online and offline/in-person interactions experienced by the blog authors and their readers. These stories were predominantly about receiving support from persons via online interactions. Daily living with HIV dialogue addressed the common experiences shared by various bloggers and their readers such as longing for normalcy. A call to action addressed a self-embraced sense of mission or purpose which was a contributing impetus to blog. Blog readers affirmed these missions in their responses. While these themes have been documented in prior qualitative research on living with HIV infection, the opportunities for online social connectedness altered the expression of these themes. Further research using unsolicited narrative blogs is warranted.

Thesis advisor: Pratyusha Tummala-Narra / The present-day sociopolitical climate, with its noxious anti-immigrant sentiment and policies, has increased the emotional stress experienced by immigrant-origin populations. This dissertation presents findings from research that explored the relationship between race-and ethnicity-based discrimination, exposure to trauma, and psychological distress among a sample of Central American–origin immigrants and refugees in the United States. Informed by socio-ecological and contemporary acculturation theory, this research extended the traumatic stress and migration literature by examining how a global sense of social connectedness, as well as a sense of belonging to one’s ethnic community or the mainstream community, may mitigate or exacerbate the influence of discrimination and trauma on mental health. In addition, this research explored the potential moderating role of immigrant generation and documentation status. Participants (N=89) between 18 and 70 years of age completed surveys both online (N=28) and in person (N=61). Survey instruments included a demographic questionnaire, the Perceived Racism Scale for Latinos (PRSL), the Trauma History Questionnaire (THQ), the Social Connectedness Scale – Revised (SCS-R), the Social Connectedness in Mainstream (SCMN) and the Social Connectedness in the Ethnic Community (SCETH) scales, as well as measures to assess for symptoms of depression (PHQ-9), anxiety (GAD-7), posttraumatic stress (PCL-C), and somatization (SSS-8). Ordinary least-squares regression analyses revealed that discrimination and exposure to trauma significantly predicted psychological distress. Higher levels of social connectedness predicted lower levels of depression, anxiety, and PTSD. Mainstream social connectedness was found to moderate the association between exposure to trauma and PTSD such that for individuals with low levels of SCMN, posttraumatic stress was consistently relatively high regardless of the degree of trauma exposure. For those individuals with high SCMN, posttraumatic stress symptoms were low when trauma exposure was low. However, all individuals regardless of their sense of mainstream belonging experienced high PTSD when trauma exposure was high. In addition, a lower sense of mainstream belonging augmented the strength of the association between discrimination on depression, whereas a stronger sense of mainstream belonging reduced the strength of this relation. Specifically, individuals with low SCMN reported higher depressive symptoms with increasing perceived discrimination, while individuals with high SCMN reported similar levels of depression even at increasing levels of discrimination. Analyses did not support moderation effects for ethnic social connectedness, immigrant generation and documentation status. The study’s strengths and limitations as well as its significance for future research and practice are discussed. Implications highlight the multifaceted and dynamic nature of belongingness in the context of discrimination and trauma, and speak to the importance of culturally responsive and multi-systemic interventions. / Thesis (PhD) — Boston College, 2018. / Submitted to: Boston College. Lynch School of Education. / Discipline: Counseling, Developmental and Educational Psychology.

INTRODUCTION: Obesity is a major public health concern for youth in the United States. Eating behaviors, such as meal skipping and eating family dinner, are associated with obesity. School connectedness and family connectedness assess the degree to which an individual feels that he or she belongs in an environment, and strong feelings of school connectedness are associated with decreased BMI. This study qualitatively evaluates the relationships between feelings of home and school connectedness and specific eating behaviors associated with obesity in an adolescent population. METHODS: Participants were recruited from an adolescent clinic at Boston Children's Hospital. Inclusion criteria for recruitment included adolescents who were: Black/ African American or Hispanic and non-White, between 13 and 19 years of age, and living in the Boston neighborhoods of Dorchester, Roxbury, or Mattapan. Participants were interviewed using a semi-structured interview guide, and participant data was analyzed by systematically identifying thematic language in the data by identifying similar phrases, patterns of descriptions, and notable disparities in participant content. RESULTS: 14 (10 females, 4 males; M=15.8 years of age) were enrolled and interviewed. Mean participant BMI was 27.3. 10 participants rarely/never skipped lunch, and 4 participants often/always skipped lunch. 6 participants ate dinner at home with their family always/ often, and 4 rarely/never ate dinner at home with their family. Most reported that their school's community, quality of education, and small environments were the most important aspects of their school. Of the 4 participants who attended school in the suburbs, 3 were connected or very connected to their school and disconnected from their neighborhoods. Every participant expressed feeling safe at school, but many cited lack of safety as their least favorite aspect of their neighborhood. Some reported that they felt safe, even though they knew that their neighborhoods were unsafe. CONCLUSION: Of the five students who felt 'very connected' to their schools, all but one always/often ate the food provided by their schools. These students discussed the ways in which their schools listened to student suggestions about school food. These feelings may suggest a stronger sense of feeling respected by one's school. Strong feelings of school connectedness in the majority of students who attend school in the suburbs warrant further exploration, as those who experience discordant home and school environments seemed more likely to embrace their school environment than their neighborhood environment. Furthermore, understanding how perceived neighborhood safety may contribute to feelings of home and neighborhood connectedness and possibly eating behaviors at or around home merits further examination.