Dissertations / Theses on the topic 'Endocrine aspects of Human behavior'

Thesis (MSc (Physiological Sciences))--University of Stellenbosch, 2006.
Early adverse life events appear to increase the susceptibility of developing psychiatric disorders later in life. The molecular mechanisms involved in the development of pathological behaviour remain unclear. Dysregulation of the hypothalamic-pituitary-adrenal axis and alterations in neurotrophic factors have been implicated.

The widely used mobile phone, as well as its related technologies had opened opportunities for a complete change on how people interact and build relationship across geographic and time considerations. The convenience of instant communication by mobile phones that broke the barrier of space and time is evidently the key motivational point on why such technologies so important in people's life and daily activities. Mobile phones have become the most popular communication tools. Mobile phone technology is apparently changing our relationship to each other in our work and lives. The impact of new technologies on people's lives in social spaces gives us the chance to rethink the possibilities of technologies in social interaction. Accordingly, mobile phones are basically changing social relations in ways that are intricate to measure with any precision. In this dissertation I propose a socioscope model for social network, relationship and human behavior analysis based on mobile phone call detail records. Because of the diversities and complexities of human social behavior, one technique cannot detect different features of human social behaviors. Therefore I use multiple probability and statistical methods for quantifying social groups, relationships and communication patterns, for predicting social tie strengths and for detecting human behavior changes and unusual consumption events. I propose a new reciprocity index to measure the level of reciprocity between users and their communication partners. The experimental results show that this approach is effective. Among other applications, this work is useful for homeland security, detection of unwanted calls (e.g., spam), telecommunication presence, and marketing. In my future work I plan to analyze and study the social network dynamics and evolution.

The effects of natriuretic peptides on vascular control were investigated. In the major part of this thesis emphasis is placed on the effects of natriuretic peptides, in particular ANP, on regulation of regional vascular volume and venous tone in healthy volunteers (Chapter 3) and patients with chronic heart failure (Chapter 4). The second part of this thesis investigates the effects and mechanisms of action of ANP, BNP and CNP on large artery function in an ovine hind limb model (Chapter 5). Finally, the actions of the latest members of the natriuretic peptide family, namely DNP and NNP are investigated in vitro using rings of rabbit aorta in organ bath experiments (Chapter 6). The important new findings of this thesis are 1. ANP regulates regional vascular volume and venous tone over a wide range of physiological and pathophysiological plasma levels without affecting compliance. 2. Most importantly, basal ANP plasma levels contribute significantly to regulation of resting vascular tone. 3. The rank order of potency of NP in the forearm capacitance vasculature of patients with chronic heart failure is ANP BNP>CNP/Urodilatin. 4. Venous ANP responsiveness is preserved in patients with chronic heart failure despite marked impairment in the resistance vasculature. This preservation may be due to preserved venous endothelial function. 5. ANP acting locally modifies pulse wave velocity via the NPRa receptor. Neither CNP (acting via the NPRb receptor) nor cANF (acting via NPRc) elicit any immediate vasoactive effects. 6. Novel natriuretic peptide (NNP), a newly isolated NP from the venom of the green mamba snake (Dendroaspis angusepticus) has arterial vasorelaxant properties similar to those of ANP and DNP.

Plants are frequently used as design components for various types of interior settings. Design professionals may specify plants because of a subconscious awareness of the human need for natural contact, or as in may cases, such as in a "sunspace", because it is traditional to do so. Past studies by behavioral and horticulture researchers have documented human preference for plants, and have shown that plants positively affect people psychologically, but little research has been done to determine whether the use of plants in interior environments can influence human behavior. Interior plantscaping is a vital and expanding type of agribusiness, with millions of dollars being spent each year to install and maintain plants specified by design professionals. Plants are frequently used for clients in industry, health care, hospitality, retail, education, and in personal residences. Demonstrating that plants influence human physical behavior in interior environments would increase their value as interior design components, and provide a powerful sales tool to the plantscaping industry. Because of the potential importance of understanding more about the influence of plants in interior spaces on human behavior, this research examines whether user behavior patterns and spatial perceptions can be changed by the simple addition of interior plantscaping. This study was conducted to determine whether the introduction of trees and plants into an underutilized area of a newly constructed interior atrium would affect user perceptions of, and/or behaviors in the space. User perceptions of and activities within the atrium were recorded on questionnaires and behavioral maps, both before and after the installation of Ficus trees and Chinese Evergreen plants. Surveys were used to collect demographic information, suggestions for improving the atrium, and to determine user perceptions via the use of 13 polar adjective pairs on a six point semantic differential scale. Maps were used to record user behaviors on the lower atrium level where the plants were placed. The majority of data were analyzed descriptively by frequencies and percentages. Semantic differential analysis was done using two-tailed t-tests at p = .05. T-tests did not prove to be significant. There was mean movement of perceived perceptions from pre- to post-test. User behavior on the lower atrium level appeared to be affected by plant installation. A preference was shown for napping under the trees, and users spent more time on that atrium level when the trees and plants were present.
Master of Science

Twitch.tv är en växande livestreaming-plattform, främst inriktad på spel. Streamers presenterar sig själva framför en livepublik. Detta leder till nya och intressanta interaktioner. I denna studie studerar jag två Twitch.tv livestreamers för att undersöka skillnaderna i beteende baserat på den interaktion som förekommer mellan dem och deras publik. Streamers publikstorlek varierade. För att undersöka skillnaderna användes följande forskningsfråga: Hur använder två livestreamers Twitch.tv för att interagera med sin respektive publik när publikstorleken skiljer sig? För att undersöka detta utfördes över 60 timmar videoanalys samt en intervju med en av deltagarna. Den insamlade datan analyserades med Erving Goffman’s (1990) Dramaturgical-teori. Resultaten visar på skillnader i beteende (Dramatisering samt Idealisering) samt skillnader mellan de båda streaminggränssnitten (Scen och kulisser). Båda deltagarna påverkades av förväntningar från deras respektive publiker samt skapade framsidor (fronts) för att leva upp till dessa förväntningar till uppträdandets fördel.
Twitch.tv is a growing platform for game related live streaming. Streamers present themselves live in front of a live audience, where innovative interactions take place. In this study, I looked at two Twitch.tv live streamers with varying audience sizes. The study was conducted to better understand the differences in behavior based on their interaction with their audiences. The research question was as follows: How do two live streamers, one big and one small, interact with their audiences through the use of different features of Twitch.tv? To do this I conducted video analyses of over 60 hours worth of streaming data as well as one interview with one of the live streaming participants. The gathered data was analyzed using Erving Goffman’s (1990) Dramaturgical theory for studying the behaviors during the streamers performances. The results show differences in both performance behavior (Dramatization and Idealization) as well as differences in their streaming interface (Stage and Set pieces). Both streamers where affected by expectations from the audience while creating fronts to maintain these expectations for the benefit of the performance.

Objective To investigate whether traffic pollutants have any effect on human cognitive functions and behavior by performing a systematic review on existing research studies. Methods Research articles were identified through four databases – CINAHL Plus, Academic Search Premier and MEDLINE via EBSCOhost and Pubmed using the online electronic resources of the libraries of the Hong Kong University. A total of 119 articles from Pubmed and 86 articles from EBSCOhost were identified, and 72 and 64 studies after limits were applied. The studies used a variety of measures to assess the effects of traffic-related air pollution and cognitive functions and behaviors in both children and adults. Results There were 19 articles in total in the systematic review – 13 on children (aged from 1- 17 years) and six on adults (aged from 26 - 83.5 years). Data were employed from nine different countries. Although there were some discrepancies in the results, there was evidence of the effects of traffic-related air pollution on the brain. Conclusions The causal relationship between traffic-related air pollution and cognitive decline cannot be clearly determined. The systematic review however, generated evidence to support the hypothesis that traffic-related air pollution may affect cognitive development in children, increase risks of behavioral disorders in both children and adults, and increase the rate of cognitive decline in older adults. As a result, this systematic review suggests that the research findings have important implications in the development of public health policy and practice.
published_or_final_version
Public Health
Master
Master of Public Health

Patronage behavior was investigated in this study with regard to the nutrition orientation of consumers. The objective of this research was to determine if consumers' patronage behavior of grocery stores, health food stores or restaurants would be significantly related to attitudes and concerns toward nutrition and toward attitudes of their overall present and future state of health. This study relied on theories of retail patronage behavior, and empirical evidence from areas of consumer behavior, nutrition, and health to provide the framework for the design of this research. This study employed the use of a questionnaire as the research method. Consumers were surveyed and asked to indicate their patronage and food purchase behaviors, their attitudes and concerns toward nutrition, and their attitudes toward their preventive health. Results and conclusions from this research support the linkage between the nutritional motivations of consumers impacting upon their decisions to patronize specific retail food establishments. That is, consumers' predispositions concerning nutrition influence where and what types of food products are purchased.
Master of Science

Dissertation (PhD)--University of Stellenbosch, 2003.
ENGLISH ABSTRACT: Concern has increased that widespread adverse effects are occurring in humans and wildlife populations as a result of exposure to environmental chemicals (mostly man-made) that disrupt the normal functioning of the endocrine system. Many pharmaceutical, agricultural and industrial chemicals, acting as endocrine modulating compounds (EDCs), have been detected in an accumulated form in food, in drinking water and in the environment. Although the levels of these chemicals can be measured analytically, it is important to evaluate biological activity. For this, animal models are used and relevant bioassays developed. These assays are based on biological markers, which are specific xenobiotically-induced physiological responses and are usually deviations in cellular or biochemical components, processes or structures. Vitellogenin is a large protein complex, produced in the liver under estrogen control and circulates in the plasma, destined for incorporation into the developing oocyte in female oviparous vertebrates. Since vitellogenin production is low or nonexistent in males, its presence may therefore be interpreted as evidence of exposure to estrogenic environmental contaminants. In this study the African Clawed Frog, Xenopus laevis was used as model to study the effects of estrogens on biochemical and physiological parameters associated with vitellogenesis. As a starting point the seasonal female reproductive cycle in a natural Xenopus laevis population in terms of ovarian state, plasma vitellogenin and plasma estrogen levels was studied. It was shown that plasma vitellogenin and estrogen levels were seasonal and correlated to a seasonal ovarian cycle, which peaked during spring. However, although seasonality existed, there were reproductively active individuals at any time during the year. Increases in plasma estrogen levels predated increases in plasma vitellogenin levels and ovarian maturation. Lipoprotein profiles, as well as plasma cholesterol, triglyceride and phospholipid concentrations were determined and it was shown that estrogen affected these in such a way that these parameters could be used as additional markers in estrogen contamination studies. In order to develop an in vitro bioassay to screen for estrogenic activity, the use of hepatic tissue cultures was investigated. Optimal culture conditions were established and increased sensitivity in the estrogenic response was obtained by using liver slices from male frogs that were pre-treated with estrogen. Validation studies proved that this bioassay could be employed for routine screening of water and chemical samples. In order to refine the Xenopus laevis vitellogenin ELISA and liver slice bioassay, existing polyclonal anti-vitellogenin antibodies were replaced by culturing monoclonal antibodies. Selected antibodies were characterised and ELISAs developed and validated. This study showed that the newly developed Xenopus laevis vitellogenin ELISA and liver slice bioassay have the potential to be employed in environmental monitoring programmes.
AFRIKAANSE OPSOMMING: Daar is toenemende besorgdheid dat afwykings in mens- en dierbevolkings voorkom as gevolg van blootstelling aan chemikalieë (hoofsaaklik mensgemaak) in die omgewing wat die normale werking van die endokrienstelsel versteur. Verskeie farmaseutiese, landbou- en industriële chemikalieë, wat as endokrienversteurders optree, is in die omgewing gevind. AI kan die vlakke van hierdie stowwe analities bepaal word, is dit belangrik om hulle biologiese aktiwiteit te evalueer. Hiervoor word diermodelle aangewend om toepaslike toetse daarvoor te ontwikkel. Hierdie toetse word baseer op biologiese merkers, spesifieke xenobioties-geïnduseerde fisiologiese reaksies, en is gewoonlik afwykings van sellulêre- of biochemiese komponente, -prosesse of - strukture. Vitellogeen ('n dooiervoorloper) is 'n lipoproteïenkompleks wat, onder estrogeenbeheer, in die lewer vervaardig word en in die plasma sirkuleer vir uiteindelike inkorporasie in ontwikkelende oësiete van vroulike, ovipare werweldiere. Aangesien daar min of geen vitellogeen in manlike diere geproduseer word, is die teenwoordigheid daarvan 'n aanduiding dat die dier aan estrogeniese omgewingsbesoedeling blootgestel is. In hierdie studie is die Platanna, Xenopus laevis, as model gebruik om die gevolge van estrogene op biochemiese en fisiologiese veranderlikes, wat met vitellogenese geassosieer word, te bestudeer. As vertrekpunt is die seisoenale voortplantingsiklus van die wyfie, in terme van vitellogeen en -estrogeen vlakke in die plasma en aktiwiteit van die ovaria bepaal. Daar is aangetoon dat die estrogeen- en vitellogeenvlakke in die plasma met die ovariumsiklus, wat gedurende die lente hoogtepunte bereik, korreleer. Alhoewel daar seisoenaliteit bestaan, was daar dwarsdeur die jaar wyfies wat ovarium dooierneerlegging getoon het. Verhoging in estrogeenvlakke het vitellogeenpieke en rypwording van die ovaria voorafgegaan. Lipoproteïenprofiele, sowel as die cholesterol- , trigliseried- en fosfolipiedkonsentrasies in die plasma is bepaal en daar is aangetoon dat estrogeen hierdie medeveranderlikes in só 'n mate affekteer dat hulle as bykomende biomerkers vir estrogeenblootstelling in besoedelingstudies gebruik kan word. In vitro Xenopus laevis lewersnitte in die weefselkultuur omgewing is ondersoek om 'n biotoets te onwikkel vir die gebruik in vinnige estrogenisiteits-toetsing van watermonsters en chemise stowwe. Die mees gunstige kultuurtoestande is bepaal en die sensitiwiteit van estrogeenreaksies is verhoog deur lewer van mannetjies, wat vooraf met estrogeen behandel is, te gebruik. Hierdie biotoets se geldigheid is gestaaf en kan in roetine eerstevlaktoetsing van watermonsters gebruik word. Die gebruik van poliklonale teenliggaampies in 'n bestaande enzyme-linked immunosorbent assay (ELISA) is vervang deur spesiaal-ontwikkelde monoklonale anti-Xenopus laevis vitellogeen teenliggaampies. Uitgesoekte teenliggaampies, spesifiek teen die estrogeengeïnduseerde proteïene, is gekarakteriseer en ELISAs saamgestel en die geldigheid gestaaf. Hierdie studie het aangetoon dat die nuut-onwikkelde Xenopus laevis vitellogeen-ELISA en lewerkultuurbiotoets die potensiaal het om In omgewingsmoniteringprogramme gebruik te word.

The incidence of overweight conditions among children and adolescents is a growing national concern. Although current literature suggests that parental health behaviors could influence health behaviors of children, studies have not explored the actual predictive relationships of parents' and their children's weight statuses and weight-related behaviors. In addition, current studies have not tested the influence of parental authority, family communication, or demographic characteristics on the relationships. This study first examines factors that contribute to overweight conditions among children and adolescents and the associated costs. Studies of interventions that target children's and adolescents' weight-related health are then reviewed and provide evidence that parental involvement contributes to intervention success. The theory of planned behavior, social cognitive theory, social action theory, and systems theory are discussed and support the notion that parental influences contribute to the development of children's weight-related health behaviors. To test the relationships, 151 young adults and their parents were recruited and completed a series of questionnaires to describe their weight statuses, dietary behaviors, and physical activity behaviors. In addition, the young adult participants completed questionnaires to further describe their parents' parental authorities and their family communication environments during childhood and adolescence. Comparisons of body mass index, average daily energy consumption, average weekly energy expenditure, and physical activity enjoyment of young adult participants and their parents were conducted with correlation analyses and paired-samples t-tests. Further, multiple regression analyses were used to explore the influence of parental authority and family communication, and demographic characteristics were also considered. The empirical results of the current study indicate that, overall, parents' weight statuses and dietary behaviors help predict weight statuses and dietary behaviors of their young adult children. Further, parental authority scales interact with the relationships. At high levels of authoritarian and permissive parental authorities, young adults tend to have weight statuses that are opposite to those of their parents; at high levels of authoritarian parenting, young adults also tend to follow opposite dietary consumption patterns. The findings in this study have implications for professional practice, parenting practices, and the design of intervention activities. Recommendations for future research are provided.

The possibility that faulty expectations about success and relapse recovery contributed to poor adherence was examined in this study. Support for such an expectancy model was sought through comparing an index of relative task magnitude to adherence rates. Instructions designed to improve adherence through changing expectations about relapse and relapse recovery were also administered to 46 clients in two clinical nutritional programs. Their adherence rates