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Martinengo, Giuseppe. "Gender Differences and Similarities in the Work-family Interface: The Importance of Considering Family Life Stages." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2123.pdf.
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Kinser, Amber E. "Putting It All on the Table: Mealtimes and Stages of Identity." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/1255.
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Barrow, Katie M., Natalie Alfandre, Kirsten Crawford, Olmo Ives Del, Emily Jason, and Annie Johnson. "Creating a Sexual Health Forum for Seniors: Preliminary Stages." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/secfr-conf/2018/schedule/14.
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Sexual expression is a natural act that occurs across the life course, unrestricted by age or physical location. Regardless if a person is 75 and residing in an assisted living facility, sex is a facet of life. Although sexual activity may slow as individuals age, interest in sex does not (Langer, 2009). Older adults maintain healthy sexual desires, yet face unique challenges when it comes to sexual expression and sexual health, which can be further complicated within the margins of a community living facility (i.e., assisted living, residential care, and nursing homes). Aside from the physiological changes that occur in mid-to-late life (e.g., menopause, erectile dysfunction), the older adult population faces growing rates of sexually transmitted infections (Centers for Disease Control and Prevention, 2017), particularly in community living facilities (Warso, 2015). Sexual assault and abuse is another issue facing community living facilities, as well as ambiguous or nonexistent policies that support and protect the rights of older persons to express themselves in a sexual manner (Connoll et al, 2012). Mystification surrounding sex in later life further compounds these issues. Moreover, a plethora of misinformation underscores societal taboos and myths surrounding sexuality and its prevalence in later life, the physical and cognitive changes that occur in later life, and the attitudes and biases (of care workers and residents) involving sexual expression of older adults residing in community living facilities. A current review of the research points to more education needed that incorporates a lifespan approach and attends to older adults in community living facilities (Langer, 2009; Villar, Fabà, Serrat, & Celdrán, 2015). Creating an environment that supports open discussion of safer sex practices, as well as encouragement (and normalization) of healthy sexual expression, can lead to an improvement in the overall wellbeing of residents living at these facilities (Syme, 2017).
The current project takes a look at the preliminary stages of developing a sexual health forum for seniors residing in an assisted living facility in northern Louisiana. This project was undertaken by an undergraduate sexual health research team comprised of students majoring in Family and Child Studies or Psychology, and/or minoring in Gerontology. The presentation will detail strategies for creating a forum for seniors, highlighting successes and challenges in navigating limited research on sexuality in late life and program development targeting older adults, as well as community standards surrounding sexual health and expression. Additionally, this presentation will offer reflexive activities for educators and practitioners addressing sexual health in aging populations, particularly in residential community living facilities.
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Altawail, Ghassan Mohammed. "Gender segmentation and its implementation in Saudi Arabia." CSUSB ScholarWorks, 2003. https://scholarworks.lib.csusb.edu/etd-project/2281.
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The purpose of this project is to gain a better understanding of gender segmentation strategy possibilities in the Kingdom of Saudi Arabia. The findings from this survey graphically illustrate and statistically demonstrate some critically important information about the consumer demographics, needs, and behaviors of the targeted female Saudi shopper.
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Fleischman, Robert Paul. "Perceptions of Title IX and gender equity the influence of life histories, sports experiences, and campus initiatives /." Diss., Online access via UMI:, 2006.
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McCabe, Heather Kirsten. "Gender Difference in Working Parents' Perceptions of Work/Family Conflict and the Role of Occupational Prestige." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2530.
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As many Americans move away from the traditional homemaker-breadwinner family model, research on gender and work/family conflict has become increasingly important and the question of gender difference in experiences of work/family conflict continues to be relevant. While there is research that shows women tend to experience significantly greater work/family conflict than men, there are also studies that have shown little or no gender difference, and some that offer evidence that men are reporting more work/family conflict. This study contributes to the debate by examining gender and occupational prestige in regard to working parents' perceptions of work-to-family and family-to-work spillover, with a quantitative analysis of national probability sampled survey data from the General Social Survey's Quality of Working Life Module from the years 2006 and 2010. The findings indicate that fathers are reporting significantly more work/family conflict than mothers, and that higher prestige work is associated with greater work/family conflict, but occupational prestige has a gendered effect with work-to-family spillover and is found to be especially salient for fathers. Overall, this study demonstrates the need for policy-makers and employers to acknowledge men's parenthood. The findings are evidence that there is a need for incentivized paternity leave initiatives in the United States, as well as more universal employee work/life programs that address the barriers to fathers utilizing family-accommodating benefits.
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Keathley, Valerie J. "LIFE ON THE BIG SLAB: IDENTITY AND MOBILITY IN THE UNITED STATES TRUCKING INDUSTRY." UKnowledge, 2014. https://uknowledge.uky.edu/geography_etds/16.
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Many changes have occurred in the United States trucking industry over the last thirty years. This study examines the effects of these changes by looking at three related themes: life on the road and life at home, body image and bodily health, and the experiences of women and sexual minorities in the industry. This research is based on a discourse analysis of interviews conducted with truck drivers and trucking industry leaders.
Most truck drivers say that they value the independent nature of their workplace. Yet the independence that is a part of the trucker mystique is challenged by increased surveillance and the availability of more invasive surveillance technologies to motor carriers and the United States government. At the same time drivers face long periods of time away from home and they experience disconnection from their families. Families must learn to adapt to the absence of their trucking loved ones which is a difficult task. However, sometimes these adaptations can result in positive changes for partners at home, such as increased independence and more authority in the home.
The bodies of truck drivers are also examined. Many drivers believe that their image as workers has taken a turn for the worst and the bodily presentation plays an important role in image. Drivers seek to set themselves apart from drivers who they think perpetuate negative images of their industry through sloppy dress and a lack of professionalism. At the same time, there is increasing evidence that the working conditions of this industry lead to unhealthy bodies that are diseased and worn out.
Finally, very little has been written about women or gays and lesbians in this workplace. Women represent only five percent of this industry and they face significant barriers to surviving in this occupation because many male workers seek to marginalize them through exclusionary practices like sexual harassment. Members of the LGBT community are represented in the industry and find both comfort and exclusion in trucking. This work also examines the sexual subcultures in trucking such as sex workers and truck chasers.
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Alsanea, Faisal. "How Saudi Students Adjust to the Gender Environment in the United States: A study of the Strategies Couples Use." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1504800531370575.
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Bransteter, Irina. "Gender Differences in Severity and Symptoms of Post War Trauma and the Effects of Persisting Psychological Trauma on Quality of Life Among Bosnian Refugees Living in the United States." Cleveland State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=csu1277921426.
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Thibodaux, Brock J. ""It's No Life Being a Steer": Violence, Masculinity, and Gender Performance in The Sun Also Rises and In Our Time." ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2111.
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Nearly all discussions of Hemingway and his work touch on the theme of masculinity, a recurrent theme in all of his works. Examinations of Hemingway and his relationship to masculinity have almost unanimously treated the author as a misogynist and a champion of violent masculinity. However, since the posthumous publication of The Garden of Eden in 1986, there has been much discussion of Hemingway’s uncharacteristic use of androgynous characters in the novel. Critics have taken this as a clue that Hemingway possessed a complex attitude regarding gender fluidity, but have failed to examine the constructions of gender and identity in his earlier fiction. By examining two of his earliest works, In Our Time (1925) and The Sun Also Rises (1926), I argue that Hemingway’s complex ideas about gender performance have been hidden just beneath the surface all along.
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Schmidt, Susanne Antje. "The midlife crisis, gender, and social science in the United States, 1970-2000." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273918.
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This thesis provides the first rigorous history of the concept of midlife crisis. It highlights the close connections between understandings of the life course and social change. It reverses accounts of popularization by showing how an idea moved from the public sphere into academia. Above all, it uncovers the feminist origins of the concept and places this in a historically little-studied tradition of writing about middle age that rejected the gendered "double standard of aging." Constructions of middle age and life-planning were not always oppressive, but often used for feminist purposes. The idea of midlife crisis became popular in the United States with journalist Gail Sheehy's Passages (1976), a critique of Erik Erikson's male-centered model of ego development and psychoanalytic constructions of gender and identity more generally. Drawing on mid-century notions of middle life as the time of a woman's entry into the public sphere, Sheehy's midlife crisis defined the onset of middle age, for men and women, as the end of traditional gender roles. As dual-earner families replaced the male breadwinner model, Passages circulated widely, read by women and men of different generations, including social scientists. Three psychoanalytic experts-Daniel Levinson, George Vaillant, and Roger Gould-rebutted Sheehy by putting forward a male-only concept of midlife as the end of a man's family obligations; they banned women from reimagining their lives. Though this became the dominant meaning of midlife crisis, it was not universally accepted. Feminist scholars, most famously the psychologist and ethicist Carol Gilligan, drew on women's experiences to challenge the midlife crisis, turning it into a sign of emotional instability, immaturity, and egotism. Resonating with widespread understandings of mental health and social responsibility, and confirmed by large-scale surveys in the late 1990s, this relegated the midlife crisis to a chauvinist cliché. It has remained a contested concept for negotiating the balances between work and life, production and reproduction into the present day.
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Fillpot, Cynthia Ann. "Role conflict and hardiness as predictors of role and life satisfaction for women occupying multiple roles." CSUSB ScholarWorks, 1994. https://scholarworks.lib.csusb.edu/etd-project/900.
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Dinh, Monica. "Adjunctive appliance wear and gender affect patients' oral health-related quality of life during the late stage of orthodontic treatment in adolescents." Thesis, NSUWorks, 2015. https://nsuworks.nova.edu/hpd_cdm_stuetd/64.
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Objective: This study was conducted to determine how oral health-related quality of life (OHQoL) changes during the late stage of comprehensive fixed orthodontic treatment in adolescents and what factors may be involved. Background: Completion of orthodontic treatment has been shown to improve patients’ OHQoL due to the changes in esthetics, function and emotional well-being. The levels of OHQoL fluctuate throughout treatment where an initial decrease within the first 6 months occurs followed by an improvement towards patients’ pre-treatment levels. At 18 months of fixed orthodontic treatment, the level is unclear. The aims of this study were to clarify the changes of OHQoL during this late stage of fixed orthodontic treatment beyond 18 months in adolescents and to identify factors, including dental extractions, patient compliance, use of adjunctive appliances, and patient demographics, which may contribute to the OHQoL. Methods: This case-control study consisted of 154 adolescent patients undergoing comprehensive fixed orthodontic treatment from the Nova Southeastern University orthodontic department. Subjects were selected based upon the number of months in comprehensive fixed orthodontic treatment. Completion of the Oral Health Impact Profile short form (OHIP-14) as well as occurrence of dental extraction during orthodontic treatment, use of adjunctive appliances, frequency of emergency and failed appointments, level of oral hygiene, and subjects’ age and gender were all recorded. Statistical analysis using structural equation modeling was used to determine the direct and indirect effects to subjects’ OHQoL. Results: The model accounted for 35% of the variance in OHQoL. There were no significant differences in average OHIP-14 scores between the initial stage of 5-7 months and final stage of 18 months and over in orthodontic treatment. The analysis of direct factors showed that females and subjects with adjunctive appliances possessed higher OHIP-14 scores. Conclusions: Treatment time beyond 18 months of treatment was not a significant factor affecting adolescents’ OHQoL. Female patients and those with adjunctive appliances expressed poorer levels of OHQoL. These factors may be attributed to the scores within the physical and psychological domains as these patients experienced pain and discomfort from appliance wear as well as negative impact on their self-esteem during comprehensive fixed orthodontics.
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Howe, Lisa A. "Spirited Pioneer: The Life of Emma Hardinge Britten." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2292.
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Emma Hardinge Britten’s life encompassed and reflected many of the challenges and opportunities afforded to women in the Victorian world. This dissertation explores the multi-layered Victorian landscape through the life of an individual in order not only to tell her individual story, but also to gain a more nuanced understanding of how nineteenth-century norms of gender, class, religion, science and politics combined to create opportunities and obstacles for women in Britten’s generation. Britten was an actor, a musician, a writer, a theologian, a political activist, a magazine publisher, a spirit medium, a lecturer, and a Spiritualist missionary. Taking into account her multiple subjectivities, this dissertation relies on historical biography to contextualize Britten’s life in a number of areas, including Modern Spiritualism and political and civic engagement in the second half of the nineteenth century in Britain, the U.S., and Australia.
The dissertation is organized thematically in a quasi-chronological manner. Time frames overlap between chapters, as Britten travels from the realm of politics to that of science and to religion. Each chapter reflects this transformation of Britten’s multiple intellectual and spiritual engagements, including performance, religion, politics and science.
Emma Hardinge Britten challenged, whether consciously or not, gendered expectations by attaining a presence in a male-dominated public. Even though her life and accomplishments pre-date the New Woman of the fin de siècle, Britten established a successful career and her life creates a foreshadowing of the larger movements to come. She was an extraordinarily politically active woman whose influence reached three continents in her lifetime and beyond.
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Kulbaga, Theresa A. "Trans/national subjects genre, gender, and geopolitics in contemporary American autobiography /." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1150386546.
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Murillo, Sofia. "The Lived Experiences of Latina Women Immigrating to the United States: Adolescent Development and Acculturation." Antioch University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1527949738986007.
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Qian, Yue. "Mate Selection in America:Do Spouses’ Incomes Converge When the Wife Has More Education?" The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1460461118.
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Alqahtani, Ebtesam M. "VISION 2030 AND FAMILY: SAUDI ARABIAN MALES' PERCEPTION AFTER STUDYING IN THE UNITED STATES." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron158073891977282.
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Lee-Garland, Sooyeon. "Impact of Transnationalism On Multiracial Challenges and Resilience Among Asian Mixed-Race Adults in the United States." Antioch University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1597927104109927.
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Svensson, Pernilla. "In the final stages of life." Thesis, Malmö universitet, Fakulteten för hälsa och samhälle (HS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-24223.
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Introduction: In order for us to create a society where we live good lives until death, we must dare to talk about the end of life. Relatives are an important part of the palliative care and it is important that they get support for managing the situation and their sorrow The Aim of this study was to investigate professionals’ dialogue with relatives of patients who are in palliative care. My chosen method was qualitative analysis through semistructured interviews with professionals’ in palliative care. To analyze the empirical data, I used the symbolic interactionism. Results show that body language, treatment and team collaboration are important and crucial aspects of the conversations between professionals and relatives. The study has confirmed that the different professions work on the same goal and have a similar approach to palliative care. In the conversation with relatives, it is important to speak truthfully, prepare and let the family's feelings and thoughts take place
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Herbert, Melissa Sheridan. "A fine line: The management of gender among women in the military." Diss., The University of Arizona, 1995. http://hdl.handle.net/10150/187134.
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Women have long been confronted with challenges to their "right" to participate in the labor force on a level equal to men. I posit that this confrontation is situated in a conflict over gendered roles and the "appropriateness" of certain jobs for women. Such an arrangement sets up a contradiction for women in the military. If a woman possesses those attributes seen as desirable, she may be seen as violating traditional gender norms. Yet, a woman possessing attributes seen as feminine may be viewed as not possessing those attributes required to be a "good soldier." Is there a narrowly defined range of acceptable behaviors for women in the military? Are there penalties for women who are perceived to be "too feminine" or "too masculine?" What might those penalties be? Finally, do women employ strategies to manage gender and, if so, what types of strategies do they employ? About two-thirds of the women in this study believe that there are penalties for women perceived as "too feminine" or "too masculine." Women who are perceived as "too feminine" face a number of penalties such as being perceived as weak, incompetent, or sexually available. The dominant penalty for being perceived as "too masculine" is to be labeled a lesbian. Forty-one percent of respondents acknowledged utilizing strategies to manage perceptions of gender. Of this group, seventy-one percent strategize toward femininity only. Seventeen percent strategize toward both femininity and masculinity and twelve percent strategize toward masculinity only. While lesbian and bisexual women were more likely to indicate that penalties exist, they were no more likely than heterosexual women to engage in management strategies. This research adds to our knowledge of how women negotiate gender conflicts. It provides empirical support for the claim that gender is not simply a role, but is an ongoing accomplishment situated within everyday encounters. Additionally, the barriers that women confront have as their foundation a complex interweaving of social constructions of gender and sexuality. By examining this relationship, this research contributes to theory which examines the intersection of gender and sexuality, and its impact on women throughout society.
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Peters, Stephanie Marie. "Signs and Symptoms of the End Stages of Life." Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/321915.
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Ellis, Timothy Roberts. "Production and mortality of early life stages of flatfishes." Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386805.
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Plankton sampling established the presence of a plaice spawning ground off the west coast of the Isle of Man in the Irish Sea. The total production of stage I plaice eggs from this spawning ground in 1993 was estimated at 7.6 x 101 • Theoretically this spawning ground could supply the local nurseries with plaice larvae. Spawning was most intense in March, before the peak in the plankton bloom in the Irish Sea. Predation on plaice eggs by clupeids was studied in March in an area of high plaice egg density to the east of the Isle of Man. Fish eggs formed the bulk of the stomach contents of sprat and herring due to the lack of alternative zooplankton food at this time of year. The later developmental stages of plaice eggs were more vulnerable to predation. This was thought to be due to the increase in pigmentation with embryonic development increasing the contrast between the egg and the water to predators that detect prey visually. Sprat and herring >80 mm showed a strong selection for plaice eggs over smaller pelagic fish eggs. However, the large eggs of plaice had a refuge in size from predation by sprat <80 mm. Smaller clupeids were feeding more actively than larger clupeids, as indicated by stomach fullness and the total number of fish eggs in stomachs. Stomach content data was combined with published biomass estimates and the daily instantaneous mortality rate of plaice eggs due to predation was estimated at 0.023 for sprat and 0.001 for herring. Sprat were therefore an important predator of plaice eggs in the Irish sea, whereas herring seemed of limited significance. Predation by fishes on O-group flatfishes was studied on a Scottish nursery ground by stomach content analysis. Fish predation was shown to be a significant source of mortality and I-group grey gurnards and gadoids were the major predators. Flounder suffered higher predation rates than plaice or dab due to the smaller size at settlement. Predation on plaice and dab was size-selective, concentrated on the smaller individuals. Smaller flatfishes were vulnerable to a greater size range and greater taxonomic range of predators. Predation by O-group cod on O-group dab was limited by the sizes of predator and prey. It was hypothesised that the times of recruitment of flatfishes and their predators to nurseries, and relative growth rates, would affect predation and hence mortality. The handling time of O-group flatfishes by O-group cod in laboratory experiments was positively related to flatfish size and negatively related to cod size. The handling time of plaice was longer than for dab of a similar size due to the difference in body shape. Profitability of flatfishes (wet weight gained per unit handling time) decreased monotonically with flatfish size over the range of prey and predator sizes used. It was therefore predicted that when O-group cod forage in the field the smallest O-group flatfishes would be the most profitable and would be behaviourally selected for. However, the selection of prey by cod was suggested to be determined by both behavioural and physical processes. There was evidence that behavioural selection of prey occurred at the ingestion stage of feeding. The current evidence for density-dependent processes in the juvenile stage of plaice was reviewed. Both the data in support of, and the processes thought to cause, density-dependent mortality in the juvenile phase were equivocal. It was hypothesised that density-dependent mortality occurs in the early egg stages of plaice and evidence, and the rationale for a potential predatory process resulting in such mortality, were presented.
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Bostock, Natalie Jean. "Work/family conflict across various life and career stages." Thesis, Nelson Mandela Metropolitan University, 2014. http://hdl.handle.net/10948/d1020157.
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This study examines Work Family Conflict including Work Interferes with Family (WIF) conflict, Family Interferes with Work (FIW) conflict, role overload, role interference and the impact of children across various life and career stages. Much of the research in this area focuses on the differences in the way the genders experience Work Family Conflict. Research has shown that various life and career stages can have a marked impact on this type of conflict and this study aims to determine how individuals in the various life and career stages experience this conflict. A correlational research design was used for this study. Using a five point likert scale, participants were asked to score their responses to seventeen items. The instrument was based on Duxbury and Mills Measure of Work Family Conflict (1990) (in Handbook of Quality-of-Life Research: An Ethical Perspective by Sirgy, 2001) with the inclusion of two additional items due to their high face validity. The questionnaire was distributed to human resources managers in organisations, friends, family members and colleagues and friends, family members and colleagues of theirs. Most of the responses were scored using a pencil and paper technique and the remainder was distributed using a Surveymonkey application on social media platforms like Facebook and Linkedin. The overall sample size of respondents was 175. The raw data was entered on an excel spreadsheet and analysed using Statistica version 12 and Microsoft Excel applications with VBA macros developed by a consultant for the Nelson Mandela Metropolitan University Unit for Statistical Consultation. . Statistics such as means, Cronbach alpha’s, relationships between factors, descriptive statistics, MANOVA and Chi-squared tests were used to analyse the data. The results of this study demonstrate the need for organisations to take heed of the various challenges that individuals face in both the workplace and home environment and the different ways in which these are experienced across various life and career stages. This will enable them to design specific interventions to mitigate the effects of Work Family Conflict and improve employee’s level of performance.
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Chmielewska, Katarzyna. "In Martha We Trust? The Cultural Significance of the Martha Stewart Phenomenon." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4267/.
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The thesis examines the relationship between Martha Stewart's rendition of domesticity and a broader cultural trend of the late 1990s U.S. domestic retreatism. It argues that the mode of construction and representation of the "domestic dream" in Stewart's programs cannot be examined outside of such concepts as class and ethnicity, whose understanding depends on the cultural, social, and political context of a given era, a context, in which they become transparent as aspects of the Western (white, patriarchal) status quo. Performing a deconstructive reading of these categories as employed by Stewart in the process of creation of her media persona, the thesis examines what the negative as well as positive reactions to "Martha Stewart" convey about the condition of American society of the late 1990s and early 2000s.
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Blankson, Charles. "Positioning and life cycle stages in the UK services industry." Thesis, Kingston University, 1999. http://eprints.kingston.ac.uk/20626/.
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This study aims to contribute to the advancement of knowledge within the domain of strategic marketing, and more specifically positioning of services. In particular this research stems from an attempt to overcome the limitations of existing positioning typologies and models and the fact that current research on the subject matter fails to reflect the sequential nature of considerations related to the management of the positioning process. Consequently, the basic aim of this research is the development of a comprehensive framework that incorporates the various decisions and activities associated with the management of positioning and the generation of managerial guidelines, for the UK services industry. Following an extensive literature review, a conceptual framework that represents a synthesis of existing positioning models is proposed. Following the development of generic positioning strategies, the model is applied in the UK plastic card sector. As a result, a number of propositions are tested and managerial recommendations are put forward. Overall, this research makes the following theoretical, methodological and managerial contributions to the theory and practice of positioning activities within the plastic card services domain. Theoretical Contributions: This thesis offers a comprehensive positioning framework which could form the basis of further investigation into the subject matter. More specifically, the following theoretical contributions to the study of positioning have been made: This thesis has attempted to examine the varying descriptions attributed to the concept and as a result has clarified the concept and suggested three main themes (i.e. perspectives, key issues and dimensions) underpinning the concept. This research has put forward an empirically supported comprehensive positioning model. Methodological Contributions: This research has developed and validated a generic, consumer derived typology of positioning strategies. Operationalisation of positioning aim(s), objective(s) and the determination of LCS have been offered. An analytical procedure suitable for determining congruence between successive phases of the proposed model has been developed. The operationalisation of LCS in the model has been expanded in terms of additional dimensions. Managerial Contributions: This research has provided a set of clearly defined, managerial guidelines that practitioners can use when attempting to apply the concept of positioning.
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McGovern, John Clarke. "Factors affecting survival of early life stages of striped bass." W&M ScholarWorks, 1991. https://scholarworks.wm.edu/etd/1539616771.
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In 1988 laboratory presentations, bay anchovy, and Atlantic menhaden tested positive as potential predators. Consumption of striped bass larvae by bay anchovy increased at higher prey densities to a maximum of 42 larvae/h at prey densities of 1,650/m&\sp3&. Examination of 229 stomachs of bay anchovy collected during peak spawning in 1988 and 1989 provided direct evidence of predation on striped bass eggs and larvae. The relationship between patterns of survival inferred from the back-calculation of juvenile hatchdates were compared with data sets describing predator and prey fields, egg production, food abundance, and changing environmental conditions during the 1988 and 1989 spawning seasons. The physical factors pH, rainfall, dissolved oxygen, and water temperature were measured at 30-minute intervals and observations of predator, prey, egg and larval densities were recorded weekly or semi-weekly. In 1988, a year of average recruitment, only 11% of the juveniles aged (n = 78) were born during the week of peak spawning when over 48% of the eggs were produced. In 1989, a year of high recruitment, the temporal distribution of juvenile hatchdates more closely followed the distribution of eggs with 30% of the juveniles (n = 96) born during the week of peak spawning when 40% of the eggs were spawned. Potential fish predators were collected in greater numbers during peak spawning in 1988 (61/100m&\sp3&) than during the same period of time of 1989 (12/100m&\sp3&). Water temperatures were lower during peak spawning in 1988 (16&\sp\circ&C) than during 1989 (19&\sp\circ&C). Also, prey items for first-feeding larvae decreased the week following peak spawning in 1988 from an average number of 194 to 74 individuals/l. Lower water temperatures and reduced food densities in 1988 may have produced a combined effect of prolonging developmental stages of striped bass eggs and larvae, thereby making them more susceptible to elevated predator densities. Dissolved oxygen values were inversely related to water temperature, reaching low values of about 6 mg/l after water temperature reached about 25&\sp\circ&C and spawning had ceased. Although pH values were usually around 7.0 throughout the 1988 and 1989 spawning seasons, pH depressions associated with rainfall were noted during both years.
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Rai, Purnima. "Effect of elevated temperatures on Trogerma variabile Ballion life stages." Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/18714.
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Master of ScienceDepartment of Grain Science and Industry
Bhadriraju Subramanyam
Heat treatment of grain-processing facilities involves using elevated temperatures of 50- 60˚C for 24 h or less to manage stored-product insects. Heat is an alternative to a non-ozone depleting fumigant sulfuryl fluoride, which was registered in the United States in 2004 for disinfestation of grain-processing facilities. In this study, life history traits of the warehouse beetle, Trogoderma variabile Ballion, were characterized on ground cat food at 28°C and 65% RH to facilitate harvesting life stages of a specific age for bioassays with heat. Eggs laid by females were observed for daily eclosion. Eggs hatched on days 6 through 10, and the mean proportion for egg hatching was 87%. Larvae hatching from eggs (first instars) were reared on ground cat food and their head capsule widths were measured every 2 d until all larvae became pupae. Head capsule widths indicated six instars and the total larval duration ranged from 28-40 d. Pupae became adults in 3-9 d. Newly eclosed unmated female adults lived 7 d longer than unmated males (16 d), whereas mated males lived 2 d longer than mated females (8 d). Eggs were not observed when food was not provided to male and female pairs. Females started laying eggs 2 d after pairing until the fifth day. The total number of eggs laid by mating pairs in the presence of food ranged from 30 to 135. Exposure of eggs, young larvae, old larvae, pupae, and adults of T. variabile at 46, 50, and 54°C and 15-20% RH for four fixed time periods showed pupae to be generally more heat tolerant than other life stages. At 46, 50, and 54°C, complete mortality of all stages occurred at 1440, 120, and 30 min, respectively. Pupae also were generally more heat tolerant than other life stages during tests in pilot flour and feed mills at Kansas State University and in a commercial grain-processing facility. However, results from pilot and commercial mills were not as conclusive as the results at fixed temperatures in the laboratory.
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Dunmore, Robyn Ann. "Demography of early life stages of habitat-forming intertidal fucoid algae." Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1364.
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The intertidal zone is finely partitioned in species distributions and abundances. The demographies of key species over varying spatial and temporal scales are fundamental to understanding the population structure and overall dynamics of habitats and assemblages. In this thesis, settlement, dispersal and early life stage survival and growth were examined in several habitat-forming intertidal fucoid algae in New Zealand and Oregon, U.S.A. Natural settlement patterns of Hormosira banksii, Cystophora torulosa and Cystophora scalaris were quantified for over three years at a semi-protected shore in southern New Zealand. Settlement was monitored in four tidal zones, within bare rock and algal habitats. Settlement was synchronous between tidal zones but the density of settlement varied spatially and temporally. There were significant differences between tidal zones, habitats and times of the year. For H. banksii, small pulses of settlement occurred year-round with greatest densities during spring and early summer. Greatest settlement occurred at low tidal zones and under adult canopies. Both Cystophora species also reproduced year-round, but had much lower settlement densities than H. banksii. Most settlement occurred during spring and summer, while only small pulses occurred in autumn and winter months. Most settlement was in the lowest tidal zone (0.4 m above chart datum), with only a few zygotes settling at higher shore zones. Canopy cover had no significant effect on settlement densities. Dispersal was examined in Durvillaea spp., H. banksii, C. torulosa and Fucus gardneri. For all species, settlement densities declined with distance from the source populations, but densities were variable between species. Durvillaea spp. dispersal was more extensive than expected, with significant settlement occurring 32 m from the source population, the maximum sample range of the study. However, settlement densities were much higher within 8 m from the source. The extensive dispersal of Durvillaea spp. is a result of the combination of small, slowly sinking eggs and the presence of buoyant mucilage. The other species studied showed far more restrictive dispersal, and much lower settlement densities. Settlement occurred 2 m from the source, but most settlement occurred under or near the canopy. The eggs of these species are much larger and sink faster than the eggs of Durvillaea spp. The consequences of settling at different shore heights and seasons were examined in H. banksii and D. antarctica in New Zealand, and F. gardneri and Pelvetiopsis limitata in Oregon. Transplant experiments tested the effects of grazing and heat/desiccation stress on survival and growth of germlings at different shore heights, during different seasons. High germling mortality was a feature of all species, but rate of mortality depended on conditions and species. There is a trade-off for settling at different times of the year; overall, growth was faster in warmer seasons, but survival was better in cooler seasons. During cooler seasons, germlings are exposed to less heat/desiccation stress, but their slow growth exposes them to grazing and competitive interactions for longer periods. For New Zealand species, shore height had large effects, with better survival and growth in the low shore. Grazers were very effective in the low shore, and heat/desiccation stress had strong effects in the mid and high shores. For Oregon species, effects of grazing and heat/desiccation stress were generally weaker than for New Zealand species. Shore height had weak effects, but ultimately low shore germlings had poor survival, primarily because of overgrowth by ephemeral algae. This is in contrast to the generalisation that survival and growth in the low shore should be better due to a more benign environment. In this study, species had specific demographies that related to their life history characteristics and responses to the local environment. Differences in settlement, dispersal abilities, survival and growth over small spatial and temporal scales clearly underpinned large scale differences in recruitment and adult distribution and abundances.
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Yu, Chun. "Susceptibility of Lasioderma serricorne (F.) life stages exposed to elevated temperatures." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/945.
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Höppner, Martina. "Advisory boards in German family companies at different life cycle stages /." [S.l. : s.n.], 2006. http://www.gbv.de/dms/zbw/520527542.pdf.
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Radi, Naseem Ismail. "Effects of copper on the life history stages of Fucus ceranoides." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272607.
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Green, Christopher C. "Effects of phytoestrogens on sensitive life history stages in channel catfish /." Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1456624541&sid=12&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Postma, Froukje M. "Selection during Early Life Stages and Local Adaptation in Arabidopsis thaliana." Doctoral thesis, Uppsala universitet, Växtekologi och evolution, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-302862.
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Organisms are often adapted to their local environment, but the role of early life stages in adaptive differentiation among populations remains poorly known. The aim of my thesis was to investigate the contribution of early life stages to the magnitude and genetic basis of local adaptation, and to identify the underlying adaptive traits. For this, I used two natural populations of the annual plant Arabidopsis thaliana from Italy and Sweden, and a Recombinant Inbred Line (RIL) population derived from a cross between these populations. By combining greenhouse and field experiments, Quantitative Trait Loci (QTL) mapping, and path analysis, I examined (1) the genetic basis of seed dormancy, (2) the contribution of differential seedling establishment to local adaptation, (3) among-year variation in selection during seedling establishment, (4) direct and indirect effects of seed dormancy and timing of germination on fitness, and (5) the adaptive value of the seed bank. I found that both the level and the genetic basis of seed dormancy were affected by the maternal environment. One major-effect QTL was identified in all maternal environments, which overlaps with the dormancy gene DELAY OF GERMINATION 1 (DOG1). Selection through seedling establishment success contributed strongly to local adaptation and genetic tradeoffs, and varied among years. Variation in seedling establishment and overall fitness among RILs could be explained by genetically based differences in seed dormancy and timing of germination. Seed dormancy affected fitness throughout the life cycle, by affecting the proportion of germinated seeds, and indirectly via effects on timing of germination, plant size and flowering time. My results suggest that a considerable portion of A. thaliana seeds enter the seed bank. I found genetic differences in dormancy cycling behaviour between the two populations, which could contribute to local adaptation. The value of a seed bank should be higher at the Swedish study site than at the Italian study site due to lower rate of seed mortality in the soil. Overall, the results of this thesis demonstrate that early life stages contribute strongly to both the magnitude and the genetics of local adaptation.
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Santos, Bárbara Rosa da Fonseca. "Toxicity interaction of cooper and salinity on Perez frog life stages." Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/7519.
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Mestrado em Ecologia, Biodiversidade e Gestão de EcossistemasPopulations of amphibians are declining worldwide. Among the major causes for such decline are chemical contamination and climate changes (e.g. increase in temperature, salinization of coastal freshwater ecosystems). Actually, the group of amphibians may be very sensitive to these stressors as they possess a thin and permeable skin with no physical protection that allows cutaneous respiration but also the diffusion of chemical agents present in the environment. Furthermore, their biphasic life cycle exposes amphibains both to aquatic, terrestrial and atmospheric contamination, potentiating the period of exposure. Consequently, it is necessary to understand the effects that chemical contamination may pose to this group of organisms and how other factors may influence their sensitivity to chemical stress. Accordingly, the present work intended at evaluating how life stage and the combination with other stressors may influence the toxicity of copper to the Perez´s frog Pelophylax perezi (Seoane). To attain this main goal, two specific objectives were delineated: (i) to compare the sensitivity of different life stages, embryos versus tadpoles, to copper (Experimental design 1), and (ii) to evaluate the influence of increased salinity (an indirect effect of climate changes in coastal freshwater lagoons) on the toxicity of copper to embryos and tadpoles of P. perezi (Experimental design 2). For this, eggs at Gosner stage 10-11 and tadpoles at Gosner stage 25 were used to carry out 96h exposure assays. For the first experiment, the two life stages were exposed to a gradient of copper plus a control (FETAX). In the second experiment, embryos and tadpoles were exposed to combinations of copper and NaCl (to simulate an increased salinity) in a complete bifactorial experimental design. In the two experiments the following endpoints were monitored: (i) for embryos, mortality was registered every 24h and at the end of the assay the final body length and malformations rate of surviving larvae were assessed; (ii) for tadpoles mortality and swimming behavior were monitored every 24h. Additionally, at the end of the experimental desing 2 the enzymatic activity, of surviving larvae/tadpoles, was quantified for catalase (CAT), cholinesterase (ChE), glutathione S-transferase (GST) and lactate dehydrogenase (LDH). The obtained results showed that embryos were less sensitive to copper than tadpoles (aproximately 50% of mortality at 1.6 mg/L Cu and LC50=0.93 mg/L Cu, respectively). Furthermore, it was observed that NaCl did not influence the lethal toxicity of copper to tadpoles, but, it significantly reduced the copper toxicity to embryos. Regarding enzymatic responses, a clear and consistent response was not observed for the tested treatments. However, for some copper concentration, the presence of NaCl induced an increase of the activity of CAT, relatively to that observed when orgaisms were exposed solely to copper, both for embryos and tadpoles. Also, in some copper concentrations, the presence of NaCl caused an increase or decrease in the activity of LDH in embryos and tadpoles, respectively. In addition, and contrarirly to what was reported for copper, it was observed that embryos were more sensitive to increased salinity (NaCl) than tadpoles. The results obtained in the present study, highlighted the need, within the context of ecological risk evaluation, to characterize the sensitivity of different life stages of amphibians to different chemicals and to the combination of diverse stressors.
As populacões de anfíbios estão em declínio a nível mundial. Duas das principais causas para este declínio são a contaminação química e alterações climáticas (e.g. aumento das temperaturas, salinização de zonas costeiras). De facto, os anfíbios podem ser muito sensíveis a estes agentes perturbadores, visto possuírem uma pele fina e permeável, sem protecção física, que permite a respiração cutânea mas também a difusão de agentes químicos presentes no ambiente. Além disso, o seu ciclo de vida bifásico expõe-os a contaminação aquática, terrestre, e atmosférica, potenciando o seu período de exposição. Consequentemente, é necessário compreender os efeitos que a contaminação química pode ter neste grupo de organismos, e de que modo outros factores podem influenciar a sua sensibilidade à perturbação química. Deste modo, o presente estudo pretendeu avaliar a influência do estádio de vida e da presença de outros agentes perturbadores na toxicidade de cobre em rã verde, Pelophylax perezi (Seoane). Para atingir este objectivo principal, foram delineados dois objectivos específicos: (i) comparar a sensibilidade de diferentes estádios de vida (embriões verusus girinos) ao cobre (Experiência 1), e (ii) avaliar a influência do aumento de salinidade (efeito indirecto das alterações climáticas em lagoas de água doce costeiras) na toxicidade de cobre para embriões e girinos de P.perezi (Experiência 2). Para tal, foram usados ovos no estádio de Gosner 10-11 e girinos no estádio de Gosner 25 para realizar ensaios de toxicicidade com 96h de exposição. Na primeira experiência, os dois estádios de vida foram expostos a um gradiente de cobre mais um controlo (FETAX). Na segunda experiência, os embriões e girinos foram expostos a combinações de cobre e NaCl (para simular um aumento de salinidade) num desenho experimental bifactorial completo. Nas duas experiências foram monitorizadas as seguintes respostas aos agentes perturbadores: (i) para os embriões, a mortalidade foi registada a cada 24h e no final do ensaio o tamanho corporal final e a taxa de malformações nas larvas sobreviventes; (ii) no caso dos girinos, a mortalidade e o comportamento natatório foram monitorizados a cada 24h. Adicionalmente, no final da segunda experiência (em que foi avaliada a influência de NaCl na toxicidade de cobre), foi quantificada a actividade enzimática da catalase (CAT), colinesterase (ChE), glutationa S-transferase (GST) e lactato desidrogenase (LDH) nas larvas (que eclodiram no final do ensaio-96h) e nos girinos. Os resultados obtidos demonstraram que os embriões foram menos sensíveis ao cobre do que os girinos (cerca de 50% de mortalidade na concentração de 1.6 mg/L Cu e LC50=0.93 mg/L Cu respectivamente). Mais ainda, foi observado que o NaCl não influenciou a toxicidade letal do cobre nos girinos, mas reduziu significativamente a toxicidade do cobre nos embriões. Relativamente às respostas enzimáticas, não foi observado um padrão consistente de repostas aos vários tratamentos. No entanto, em algumas concentrações de cobre, combinadas com NaCl, observou-se que a presença de NaCl induziu a actividade da enzima CAT relativamente ao efeito observado apenas pela presença de cobre. Verificou-se ainda que, em algumas concentrações de cobre, a presença de NaCl induziu uma redução e um aumento da actividade da LDH em girinos e embriões, respectivamente, em comparação com a actividade da enzima em exposições só a cobre. Mais ainda, e contrário ao que foi registado para o cobre, foi observado que os embriões apresentaram uma maior sensibilidade ao aumento da salinidade (NaCl) do que os girinos. Os resultados obtidos no presente estudo destacam a necessidade de, num contexto das avaliações de risco ecológico, caracterizar a sensibilidade dos diferentes estádios de vida dos anfibios a diferentes químicos e a combinações de de agentes perturbadores.
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Brandt, Erin. "Externally-Expressed Fluorescence across Sexes, Life Stages, and Species of Spiders." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/893.
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Although all spiders possess fluorophores in their hemolymph, the expression of external fluorescence is much more restricted. The purpose of this study was to evaluate differences in externally-expressed fluorescence between sexes, life stages, and species of spiders. To approach this question, we developed novel instrumentation to capture fluorescence with photographs of our specimens. We paired these fluorescence measurements with spectrometer measurements to attempt to determine the role that fluorescence plays in the overall coloration in spiders. The study was divided into four sections. First, we examined how fluorescence varies in sexes and life stages in Misumena vatia, an ambush predator that typically preys on insects when they are on flowers. We found that adult females possess brighter external fluorescence than males in all body areas that we measured. We also found that external fluorescence remains relatively similar through life stages in females, but darkens over the course of a male's life. It is likely that the differences between males and females relate to differences in feeding ecology. External fluorescence may contribute to a visual signal allowing females to visually blend in with flowers. The second study involved a series of experiments to determine whether freezing spiders at a temperature of -80°C affects their fluorescence intensity. In spiders considered “white thomisids”, fluorescence intensity increased after freezing, whereas fluorescence brightness in darker-pigmented spiders did not change to any similar extent. It seems likely that tissue trauma due to freezing is the cause of increased fluorescence intensity after freezing. The third study examined fluorescence brightness across ages and life stages of Araneus diadematus, a spider which is exposed to the sun, but builds large webs in which to snare prey. We found that, unlike M. vatia, adult males are the more brightly fluorescent sex, with adult females and all immature life stages possessing significantly less bright external fluorescence. It is unclear why these differences exist, but differences in ecology between adult males and all other life stages could play a role. Additionally, dim fluorescence may contribute to subtle patterning and/or convey photoprotection benefits to immatures and adult females. In the final study, we examined external fluorescence across the Thomisidae family. Because of a relatively large number of species with a small sample size, we divided them into “white” and “dark” thomisids based on taxonomy and what is known about ecology. The white thomisids tend to be prey on insects on the exposed surfaces of flowers, whereas dark thomisids more often reside in leaf litter and crevices. We found that white thomisids fluoresce more brightly than dark thomisids. There were no differences between the sexes in either group, however. The differences between white and dark thomisids may be related to differences in feeding ecology, whereas males and females of the same group tend to have similar ecological characteristics, and also possess similar levels of fluorescence brightness.
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Farley, C., Aruna Kilaru, Shivakumar Devaiah, M. Roth, A. Shiva, P. Tamura, and Ruth Welti. "Composition of N-Acylethanolamines in Physcomitrella Patens at Varying Life Stages." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/4825.
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Siriwardena, P. P. G. S. N. "Tolerance and early life stages of Tilapia (Cichlidae:Tilapiini) to metal stress." Thesis, University of Stirling, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384838.
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Rye, Rebekah. "Gender Differences in Lower Extremity Kinematics throughout Various Stages of a 5K Run." Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/28402.
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Running has been a popular sport because of convenience and health benefits. Fatigue among recreational runners may alter running mechanics, thereby increasing the risk for injury. The purpose of this study was to evaluate changes in lower extremity biomechanics throughout a 3.1 mile (5K) run. Ten male and ten female participants wore reflective markers to capture contralateral pelvic drop, knee adduction, knee abduction, and hip adduction. Participants ran 3.1 miles (5K) on a treadmill at a self-determined pace. A two-way, repeated measures ANOVA was conducted to capture the within-subject data across time and between-subject comparing differences in gender. Females had significantly greater contralateral pelvic drop but it did not change over time. Knee abduction angles significantly declined over the five observations. Gender differences and effects of distance can alter the biomechanics in recreational runners. More research is needed to identify predisposing factors to the development of chronic running injuries.North Dakota State University. Department of Health, Nutrition, and Exercise Sciences
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Mai, Dan T. "Sustaining family life in rural China : reinterpreting filial piety in migrant Chinese families." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:8e679650-a857-4f3c-a5c1-770a1bff848e.
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This study explores the changing nature of filial piety in contemporary society in rural China. With the economic, social and political upheavals that followed the Revolution, can 'great peace under heaven' still be found for the rural Chinese family as in the traditional Confucian proverb,"make yourself useful, look after your family, look after your country, and all is peaceful under heaven"? This study explores this question, in terms not so much of financial prosperity, but of non-tangible cultural values of filial piety, changing familial and gender roles, and economic migration. In particular, it examines how macro level changes in economic, social and demographic policies have affected family life in rural China. The primary policies examined were collectivisation, the hukou registration system, marketization, and the One-Child policy. Ethnographic interviews reveal how migration has affected rural family structures beyond the usual quantifiable economic measures. Using the village of Meijia, Sichuan province, as a paradigmatic sample of family, where members have moved to work in the cities, leaving their children behind with the grandparents, the study demonstrates how migration and modernization are reshaping familial roles, changing filial expectations, reshuffling notions of care-taking, and transforming traditional views on the value of daughters and daughters-in-law. The study concludes that the choices families make around migration, child-rearing and elder-care cannot be fully explained by either an income diversification model or a survival model, but rather through notions of filial piety. Yet the concept of filial piety itself is changing, particularly in relation to gender and perceptions about the worth of daughters and the mother/ daughter-in-law relationship. Understanding these new family dynamics will be important for both policy planners and economic analysts.
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Birget, Philip Laurent Guillaume. "Evolutionary ecology of parasites : life-history traits, phenotypic plasticity, and reproductive strategies." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/28805.
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Adaptive phenotypic plasticity, the ability of a genotype to give rise to different phenotypes in different environments, evolves to allow organisms to fine-tune their life-history traits according to the varying conditions they encounter during their lives. Reproductive investment - the manner in which organisms divide their resources between survival and reproduction - is well studied in evolutionary ecology because it is a key determinant of fitness. However, whilst plasticity in reproductive effort is well understood for free-living multicellular taxa (such as insects, birds, and mammals), the application of evolutionary theory for plasticity and life history strategies to unicellular parasites and pathogens is lacking. In this thesis, I use empirical and theoretical approaches to uncover how differential resource allocation to non-replicating, sexual stages (gametocytes) versus asexually replicating stages can be harnessed by the rodent malaria parasite Plasmodium chabaudi to maximise its fitness across the often very variable conditions it encounters during infections. Differential allocation between those stages is equivalent to the fundamental life-history trade-off between survival and reproduction because gametocytes are responsible for between-host transmission (i.e. reproduction of the infection) whereas asexual parasites mediate host exploitation and within-host survival. A suite of within-host models reveal that malaria parasites could gain considerable fitness benefits in the face of low levels of drug treatment if they reduce their investment into gametocyte production ("reproductive restraint"), thereby assuring the continuity of the infection and capitalising on opportunities for future transmission. In contrast, high levels of drug treatment typically select parasites to commit all of their resources to gametocyte production ("terminal investment"), to escape a host that does not offer much opportunity for future transmission. My experiments reveal that P. chabaudi increases both its reproductive investment and its asexual replication rate in anaemic hosts (i.e. host that have a low density of red blood cells), suggesting that parasites profit from host anaemia and can afford high investment in gametocytes ("affluent investment"). I also uncover plasticity in a number of traits that underpin asexual replication rate, including invasion preference for different ages of red blood cells, but it is plasticity in the number of progeny (merozoites) per infected cell that is the main contributor to asexual replication rate. My experiments also reveal genetic variance in plasticity of the life-history traits investigated, which has profound implications for their evolution. Furthermore, plastic modification of these traits is associated with minimal costs or constraints, so that parasites can rapidly match life-history traits appropriately to the within-host environment. Severe anaemia is one of the deadliest symptoms of malaria, so observing that virulence and infectiousness increases in anaemic hosts has also fundamental clinical implications. Finally, the empirical and theoretical observations of affluent investment, reproductive restraint and terminal investment match theoretical predictions of how organisms should behave in varying environments, confirming P. chabaudi as a useful model system to test life-history theory.
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Jacobson, Peter James. "Sensitivity of early life stages of freshwater mussels (Bivalvia: Unionidae) to copper." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-12172008-063755/.
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Lane, Ackley Charles. "Early life stages under ocean acidifcation : direct effects, parental influence, and adaptation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/202353.
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Stephens, Susan M. "The effects of petroleum hydrocarbons on the early life stages of turbot." Thesis, University of Exeter, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361319.
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Foltz, John Richard. "Impacts of contaminated sediment remediation on early life stages of rainbow trout." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Fall2009/J_Foltz_113009.pdf.
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Thesis (M.S. in engineering)--Washington State University, December 2009.Title from PDF title page (viewed on Feb. 4, 2010). "College of Engineering and Architecture." Includes bibliographical references (p. 50-55).
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Lück, Sarah. "Quantifying the Life Stages of a Biomolecule: Implications for the Circadian Transcriptome." Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18598.
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Viele biologische Prozesse im Verhalten von ganzen Organismen, aber auch in den Prozessen und
der biochemischen Zusammensetzung von Zellen zeigen einen zirkadianen Rhythmus, also einen Rhythmus mit einer Periode von etwa 24 Stunden.
Diese 24-Stunden-Rhythmen sind in der Genexpression auf allen Ebenen zu finden: von der Tran-
skriptionsinitiation bis zur Proteindegradation. Auf Transkriptebene, zirkadiane mRNA-Produktion
und mRNA-Abundanz ist umfassend gemessen. Auf der anderen Seite, zirkadiane posttranskriptionelle Regulation ist weit weniger verstanden. In dieser Arbeit untersuche ich, wie bisher ungemessene, posttranskriptionelle Prozesse die rhythmischen Eigenschaften der Genexpression beeinflussen. Dazu beschreibe ich die Lebensstadien eines Bio-Moleküls mit einem Modell-Motiv, einer einfachen Differentialgleichung mit zeitabhängigen, rhythmischen Raten.
Als erstes diskutiere ich die Einschränkungen von Phase und Amplitude zirkadianer Transkripte, die nur von konstanter PTR beeinflusst werden. Bei vielen gemessenen Transkripten sind diese Einschränkungen verletzt. In diesen Fällen muss es eine rhythmische PTR geben. Ich untersuche, welche rhythmische PTR diese Fälle erklären können und führe einen statistischen Test ein, der auf unbeobachtete, rhythmische PTR testet. Durch die Analyse zweier Datensätze von Mausleber und -niere finde ich, dass 18% aller zirkadianen Gene in Niere und 34% in Leber rhythmisch
posttranskriptionell reguliert sind.
Im zweiten Teil analysiere ich weitere Aspekte von PTR in einem Hypothesen-getriebenen Ansatz.
Ich zeige, dass Spleißen mit einem Rhythmus von 24 Stunden 12 Stunden-Rhythmen in der Abundanz von mRNA erzeugen kann. Als nächstes schlage ich ein Modell vor, das rhythmische Degradation von Mitgliedern der zirkadianen Uhr beschreibt. Schließlich erweitere ich das Modell-Grundmotiv zu einer partiellen Differentialgleichung (PDG), die das “Altern” von Molekülen beschreibt.In almost all organisms on Earth, many behavioral, physiological, and biochemical activities oscillate with a circadian rhythm, a rhythm with a period of about 24 hours. In gene expression, the 24-hour-rhythm can be found on all stages: from transcription initiation to protein degradation. On the transcript level, circadian mRNA production and mRNA abundance are comprehensively charted through numerous genome-wide high throughput studies. Circadian post-transcriptional regulation, however, is less well understood. In this thesis, I will investigate how unobserved post-transcriptional processes influence rhythmic properties of gene expression. To this end, I quantify the life-stages of biomolecules using one modeling motif, a simple ordinary differential equation describing production and degradation with time-dependent rhythmic rates. This basic modeling motif is systematically varied to examine and discuss various influences of post-transcriptional regulation (PTR) on circadian mRNA expression. I first discuss the restrictions of rhythmic phase and amplitude of circadian transcripts influenced by non-rhythmic PTR. For many genes these restrictions are violated and we have to assume the existence of a rhythmic PTR. I discuss which rhythmic PTR can explain these findings and further introduce a statistical test to quantify the extent of unobserved rhythmic PTR. Analyzing two data sets on mouse liver and kidney, I find that 18% of circadian genes in kidney and 34% in liver are under rhythmic post-transcriptional control. In a second part, I analyze more specific aspects of PTR in a hypothesis-driven approach. Firstly, I find that splicing with a rhythm of 24 hours is able to generate 12-hour rhythms in abundance of mature mRNA. Secondly, I propose and analyze a model to investigate rhythmic degradation of core clock genes. And finally, I extend the core modeling motif to a partial differential equation (PDE) model that accounts for the “aging” process of molecules.
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Oliveira, Rhaul. "Zebrafish early life-stages and adults as a tool for ecotoxicity assessment." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/8838.
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Mestrado em Toxicologia e EcotoxicologiaO peixe-zebra (Danio rerio) é um vertebrado modelo grandemente utilizado em investigação científica em todo o mundo. Nas últimas décadas, foram desenvolvidos protocolos e técnicas que permitem o uso deste organismo na avaliação de ecotoxicidade. Com o presente trabalho pretendeu-se aplicar múltiplas técnicas para avaliar a toxicidade de diferentes químicos em Danio rerio a nível letal e subletal (embriotoxicidade, genotoxicidade e biomarcadores) realizando testes com embriões e adultos. Numa primeira fase foram selecionados químicos representativos de diferentes tipos de contaminação ambiental. O dicromato de potássio (metal pesado), o triclosão (bactericida) e as δ-endotoxinas (toxinas Bt) foram escolhidos com base nos seus diferentes modos de ação, uso e potecial risco ecológico. Foram realizados ensaios ecotoxicológicos utilizando o peixe-zebra nos diferentes estádios do seu ciclo de vida. Os protocolos da OECD “Fish, Acute Toxicity Test” e “Fish Embryo Test” foram adoptados para avaliação da toxicidade aguda, alterações comportamentais e embriotoxicidade (no caso dos testes com embriões). Foram ainda incluidos ensaios para determinação da actividade de algumas enzimas (colinesterase (ChE), glutationa-S-transferase (GST) e lactato desidrogenase (LDH)) e da genotoxicidade (teste do micronúcleo, anomalias nucleares e teste do cometa). Os resultados mostraram que os testes com embriões são muito mais informativos que os testes com adultos visto que incluem uma gama de endpoints mais vasta, permitindo obter um “perfil de toxicidade” específico para cada químico testado. Os efeitos a nível do desenvolvimento embrionário (anomalias e atrasos) e os biomarcadores mostraram ser os endpoints testados mais sensíveis. O teste com embriões de zebrafish mostrou assim ser uma óptima ferramenta para avaliação da toxicidade contribuindo para uma melhor compreensão dos efeitos dos tóxicos abordados e uma melhor perspectiva do seu risco ambiental.
The zebrafish (Danio rerio) is a model vertebrate extensively used in scientific investigation worldwide. In the last decades, protocols and techniques have been developed in order to evaluate the effects of chemicals at different levels of biological organization of this species and to characterize the lethal and sublethal effects of pollutants. The main aim of this study was to assess the toxicity of different classes of chemicals to Danio rerio at lethal and sublethal levels applaying multiple techniques (embryotoxicity, genotoxicity and biomarkers) with adults and embryos. In the first phase of this study was the selection of chemicals in order to contemplate different type of contaminants. Potassium dichromate (heavy metal), triclosan (biocide) and δ-endotoxins (Bt toxinsbiopesticide) were selected due to their different modes of action, use and potential environmental risk. Ecotoxicological assays were performed using different life-stages of zebrafish. The OECD protocols “Fish, Acute Toxicity Test” and “Fish Embryo Test” were followed. Acute toxicity, behavioral alterations and embryotoxicity were evaluated. Adaptations in OECD protocols were performed in order to enable tissue sampling to be used in enzymatic activity assays (acetylcolinesterase – ChE; glutatione-S-trasferase – GST, lactate desidrogenase – LDH) in genotoxixity assays (micronuclei and COMET) and in citotoxicity assays (nuclear abnormalities). Results obtained showed that Danio rerio early-life stages test is much more informative than test with adult fish as they include a wide range of endpoints allowing the obtaining of a more specific toxicity profile for each chemical tested. Effects on embryonic development (anomalies and delays) and biomarkers seemed to be the most sensitive endpoints. Zebrafish embryo test showed to be an excellent tool for toxicity evaluation contributing for a better understanding of the effects of the selected chemicals and for a more accurate prespective of their environmental risk.
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