A study of the relationship between the three-year-old's interest-span to children and to play activity

Thesis (Ed.M.)--Boston University, 1946. This item was digitized by the Internet Archive

A Model of Evolutionary Dynamics with Quasiperiodic Forcing

AbstractEvolutionary dynamics combines game theory and nonlinear dynamics to model competition in biological and social situations. The replicator equation is a standard paradigm in evolutionary dynamics. The growth rate of each strategy is its excess fitness: the deviation of its fitness from the average. The game-theoretic aspect of the model lies in the choice of fitness function, which is determined by a payoff matrix.Previous work by Ruelas and Rand investigated the Rock-Paper-Scissors replicator dynamics problem with periodic forcing of the payoff coefficients. This work extends the previous to consider the case of quasiperiodic forcing. This model may find applications in biological or social systems where competition is affected by cyclical processes on different scales, such as days/years or weeks/years.We study the quasiperiodically forced Rock-Paper-Scissors problem using numerical simulation, and Floquet theory and har- monic balance. We investigate the linear stability of the interior equilibrium point; we find that the region of stability in frequency space has fractal boundary

Antibody Testing and Lyme Disease Risk

Lyme disease test results for >9,000 dogs were collected from participating veterinary clinics. Testing was conducted by using the IDEXX 3Dx kit, used widely by Maine veterinarians to screen clinically normal dogs during heartworm season. This study demonstrates how this test can be a valuable public health disease surveillance tool

The role of local food in destination marketing : a South African situational analysis

In the tourism industry local and regional food holds great potential as a contributor to sustainable competitiveness at a destination. However, from an analysis of the literature and promotional material of South African and key international destinations, there is an indication that the contribution of food to sustainable tourism and the marketing of destinations has received very little attention globally as well as in South Africa. A framework and guidelines for developing and implementing food tourism could enable destination marketers and entrepreneurs to optimise the tourism potential of local and regional food. To this end a Strategic Food Tourism Destination Marketing Framework was conceptualised and was based on the findings of a South African situation analysis and international trends and best practices. The South African situation analysis entailed an empirical investigation into food tourism, a key component of destination marketing in South Africa, to determine its current status, future potential and initiatives. Regional and provincial destination marketing organisations were involved in the research process To support the Strategic Food Tourism Destination Marketing Framework, two key tools were developed, namely FOODPAT (a tourism and culinary atlas linked to a geospatial database) and a Product Potential and Attractiveness Tool. The framework and tools were tested in a South African destination, the Winelands of the Western Cape. Its application revealed that the stakeholder users were successfully provided with mechanisms to develop and implement food tourism. This study presents the key components and gives an evaluation of the framework and tools that were developed. Guidelines and recommendations for the development, packaging and marketing of local and regional foods are postulated. Proposals for future research are put forward. AFRIKAANS : Plaaslike en streeksvoedsel het potensiaal om by te dra tot volhoubare kompeterendheid in toerismebestemmings. ‘n Analise van resente literatuur en promosiematerial van Suid-Afrikaanse en sleutel internasionale bestemmings bevestig dat in Suid-Afrika en wêreldwyd relatief min aandag aan die bemarking en bydrae van plaaslike en streeksvoedsel tot volhoubare toerisme en die bemarking van bestemmings gegee is. ‘n Raamwerk en riglyne vir die ontwikkeling en implementering van voedseltoerisme kan bemarkers en entrepreneurs van ‘n bestemming in staat stel om die toerisme potensiaal van plaaslike en streekskos te bevorder en optimaal aan te wend as ‘n bemarkingsmiddel. Gevolglik is ‘n Strategiese Voedseltoerisme Bestemming Bemarkingsraamwerk gekonseptualiseer, gebaseer op die bevindinge van ‘n Suid-Afrikaanse situasie-analise, sowel as internasionale neigings en praktyke. Die Suid-Afrikaanse situasie-analise het ‘n empiriese ondersoek behels van streeks- en provinsiale bestemmings- bemarkingsorganisasies om sodoende die status tans, toekomstige potensiaal en voedseltoerisme inisiatiewe as sleutelkomponent van bestemmingsbemarking in Suid-Afrika te bepaal. As ondersteuning vir die Strategiese Voedseltoerisme Bestemming Bemarkingsraamwerk is twee primêre hulpmiddels ontwikkel, naamlik: FOODPAT (‘n toerisme- en voedselatlas, gekoppel aan ‘n geografiese databasis) en ‘n Product Potential and Attractiveness Tool. Die raamwerk en hulpmiddels is by ‘n Suid-Afrikaanse bestemming, naamlik die Wes Kaapse Wynlande, getoets en het rolspelers sodoende van hulpmiddels voorsien om voedseltoerisme te ontwikkel en te implementeer. Hierdie studie beskryf en evalueer die sleutelkomponente, asook die raamwerk en hulpmiddels wat ontwikkel is. Riglyne en aanbevelings vir die ontwikkeling, verpakking en bemarking van plaaslike en streekskosse word voorgestel. Voorstelle vir toekomstige navorsing word ook aangedui.Thesis (PHD)--University of Pretoria, 2007.Tourism Managementunrestricte

From war economies to peace economies : the challenge of post-conflict reconstruction in Sierra Leone

The difficulty of transforming war economies into peace economies has become increasingly problematic in the search for long-term peace and stability in Africa. In many African countries such as Sierra Leone, Angola and the Democratic Republic of Congo, conflict actors have created distinct war economies in order to maintain the conflict in these countries. The enduring nature of the war economies presents a unique challenge to actors involved in ensuring that peace returns to a country by applying a peacebuilding strategy. The economic environment during a conflict has a vast influence on a post-conflict economy and a post-conflict reconstruction strategy. Although post-war rebuilding occurred during the reconstruction of Europe and Japan after the Second World War, the terms "post-conflict peacebuilding" and "post-conflict reconstruction" have only came to prominence during the mid-1990s. Using the case study of Sierra Leone, this study explores the challenge of war economies and its impact on post-conflict reconstruction. Sierra Leone presents an appealing case study as the country experienced a very profitable war economy during the armed conflict in the country between 1991 and 2002, and continues to struggle to transform this war economy into a peace economy. The case study of Sierra Leone is well researched, however, most studies focus on the conflict period, and only briefly look at the post-conflict period. In addition, discussions of post-conflict reconstruction in Sierra Leone have failed to adequately address the challenges presented by the war economy. This study uses existing analyses about the war economy in Sierra Leone, and links these to the current post-conflict reconstruction strategy, focusing specifically on the economic dimension. Therefore, this study represents a departure from traditional approaches to exploring war economies because it considers the direct impact these economic systems have on the process of post-conflict reconstruction.Dissertation (MA)--University of Pretoria, 2010.Political Sciencesunrestricte

Cost-effectiveness of Universal Hepatitis C Virus Screening of Pregnant Women in the United States

BACKGROUND:Hepatitis C virus' (HCV) chronic prevalence among pregnant women in the United States doubled nationally from 2009-2014 (~0.7%), yet many cases remain undiagnosed. Screening pregnant women is not recommended by the Society of Maternal-Fetal Medicine or the Centers for Disease Control and Prevention, despite new American Association For the Study of Liver Diseases (AASLD)/Infectious Diseases Society of America (IDSA) guidelines recommending screening for this group. We assessed the cost-effectiveness of HCV screening for pregnant women in the United States. METHODS:An HCV natural history Markov model was used to evaluate the cost-effectiveness of universal HCV screening of pregnant women, followed by treatment after pregnancy, compared to background risk-based screening from a health-care payer perspective. We assumed a HCV chronic prevalence of 0.73% among pregnant women, based on national data. We assumed no Medicaid reimbursement restrictions by fibrosis stage at baseline, but explored differing restrictions in sensitivity analyses. We assessed costs (in US dollars) and health outcomes (in quality-adjusted life-years [QALYs]) over a lifetime horizon, using new HCV drug costs of $25 000/treatment. We assessed mean incremental cost-effectiveness ratios (ICERs) under a willingness-to-pay threshold of$50 000/QALY gained. We additionally evaluated the potential population impact. RESULTS:Universal antenatal screening was cost-effective in all treatment eligibility scenarios (mean ICER <$3000/QALY gained). Screening remained cost-effective at a prevalence of 0.07%, which is the lowest estimated prevalence in the United States (in Hawaii). Screening the ~5.04 million pregnant women in 2018 could result in the detection and treatment of 33 000 women, based on current fibrosis restrictions. CONCLUSIONS:Universal screening for HCV among pregnant women in the United States is cost-effective and should be recommended nationally

Identification of digallated and methylated catechins using UPLC/MS/MS and development of a rapid analysis method for theanine in tea (Camellia sinensis (L.) O. Kuntze) utilizing evaporative light scattering detection

Theanine is a free, non-protein amino acid found in Camellia sinensis (tea) leaves. It is the main amino acid component in tea and contributes 1 to 2% of the dry weight of tea leaves. The content of amino acids is a key green tea quality parameter. High grade teas contain high amounts of theanine. It is responsible for the sweet, brothy umami taste of green tea. To date there is no international standard method for the analysis of theanine in tea samples. Several methods with different advantages and disadvantages have been reported but most of them are unsuitable for routine quality control analysis in commercial tea samples. In this study, a high performance liquid chromatography (HPLC) method with evaporative light scattering detection for the determination of theanine in tea samples has been developed. Chromatographic separation of theanine was achieved by reverse phase HPLC using a phenyl-hexyl column and isocratic water elution within 8 minutes. The method requires no sample derivatization and includes simple sample clean-up. Applying the same chromatographic conditions to a widely available C18 column, separation of theanine was achieved within 10 minutes. The successful application of the C18 column renders this method widely applicable. The method is linear over several orders of magnitude and the LOD are 11.53 and 10.83 μg/ml and the LOQ are 39.44 and 35.10 μg/ml for the phenyl-hexyl and C18 column, respectively. Simple but effective sample preparation and polyvinylpolypyrrolidone pre-treatment, along with the short analysis time facilitates high sample throughput (~40 samples can be prepared in an 8 hour day with overnight analysis by HPLCELSD). The method is selective, precise, accurate and practical for the quantification of theanine in tea extracts and was successfully used to determine theanine content in a variety of tea samples. The sensitivity and simplicity of this method renders it suitable for use in routine theanine analysis in quality control laboratories. Green tea, a simple refreshing beverage, has been believed to have therapeutic uses for centuries. Scientists have recognized that the wide range of physiological functions of green tea is due to the presence of catechins. An increasing body of evidence is showing that methylated forms of catechins have potent inhibitory activities to allergies. In addition to the methylated catechins, another relative novel group of catechins exists, namely digallated catechins. The medicinal value of these compounds is not yet known, but it is reasonable to speculate that the antioxidant capacity of digallated catechins will be superior to that of epigallocatechin gallate due to the 3 additional hydroxyl groups provided by the second gallic acid moiety. In this study reverse phase UPLC/ESI-MS/MS was effectively applied to investigate the presence of digallated and methylated catechins in crude tea extract. Low abundance catechins (-)-epigallocatechin-(O-3”-methyl) gallate ([M + H]+, m/z 473) and (-)-epicatechin-3-(O-3”-methyl) gallate ([M + H]+, m/z 457) were successfully detected at 31.9 and 37.5 minutes, respectively. The 2 digallated catechins investigated could not be detected, possibly due to being present at concentrations below the limit of detection. Compared to conventional HPLC/ESI-MS/MS, increased resolution and sensitivity, 80% less use of solvent and significantly reduced analysis times were observed.Dissertation (MSc)--University of Pretoria, 2009.Biochemistryunrestricte

The Effect of Marriage verses Cohabitation on Sexual Communication in Latino, African American, and Caucasian Adults

This study focuses on the effect of communication on sexual relationship satisfaction when comparing cohabiting couples with married couples. Communication is an important part of relational and sexual satisfaction. Research was conducted using scholarly journal articles and quantitative data from questionnaires. Fifty-four questionnaires were completed by males and females that were at least forty years, married or cohabitating, and identified as Latino, African American, or Caucasian. The data from the questionnaires found that both heterosexual and homosexual couples in domestic partnerships had better sexual communication than those who were married. People from diverse backgrounds can relate to the data collected because marriage and sexual communication are relevant to people all over the worl