Incorporation of nitrogen from crop residues into light fraction organic matter in soils with contrasting management histories

The proportion of N from crop residues entering the light-fraction organic matter (LFOM) pool was investigated in soils with contrasting soil organic matter and microbial characteristics arising from different management histories. A laboratory experiment was conducted in which 15N-labelled sugar beet, Brussels sprout or ryegrass shoots, which possessed a range of C/N contents, and hence different biochemical qualities, were incorporated into a sandy–loam soil collected from within a field (FC) or from the field margin (FM). Amounts of C and N incorporated into LFOM were determined after 112 days. The FC and FM soils had organic C contents of 0.9% and 2.5%, respectively. Addition of crop residues increased total LFOM N content and reduced its C/N in FC soil but had no effect on total LFOM N or its C/N in FM soil. Ryegrass incorporation into FC was the only treatment in which there was a net increase in LFOM C. Isotopic analysis indicated that more crop-residue-derived N became incorporated into the LFOM N pool in FM relative to FC soil, with per cent crop residue N incorporated ranging from 25.9% to 35.3% in FC and between 38.9 and 68.5 in FM. Incorporation of crop residues had a positive priming effect on pre-existing LFOM N in FM but not FC soil. We conclude that the characteristics of plant material, together with differences in soil organic matter and microbiology resulting from contrasting management, determined the amount of crop residue C and N incorporated into both HFOM and LFOM

Mathematical models of gonorrhoea and chlamydia: Biology, behaviour and interactions

Gonorrhoea and chlamydia are curable, bacterial, sexually transmitted infections (STIs) of humans, with important long term consequences for health. Their epidemiology and biology are reviewed in chapter one. The way the biology of the organisms and the behaviour of human hosts interact to influence the patterns of infection and the potential impact of interventions is the subject of the main body of the thesis. Mathematical models are presented, together with empirical data, to gain a better understanding of the epidemiology of gonorrhoea and chlamydia. New approaches are applied, using more complex measures of disease occurrence including reinfection (subsequent infection by the same organism) or coinfection (infection with both organisms simultaneously). Coinfection with gonorrhoea and chlamydia is investigated in chapter two. The third chapter investigates the importance of heterogeneity in human behaviour (i.e. level of sexual activity, mixing patterns within and between populations) on the spread of disease in subpopulations, using a model incorporating race, gender and sexual activity level. This was parameterised and validated using data collected in South East London. In chapter four, models of reinfection are used to investigate the interaction of population level parameters such as degree of assortative mixing and rates of reinfection. In chapter five, the characteristics of individuals coinfected with both organisms are shown to provide additional information useful in determining how infection is distributed across a population. The biology of the organism is demonstrated, in the fifth chapter, to play an important role in the prevalence and incidence of disease within the host population. The impact of the emergence of resistant or asymptomatic phenotypes under selective pressure by different treatment regimens is quantified using a two strain model, including asymptomatic and symptomatic infections. The final chapter considers the contribution of the research and discusses the implications of the results for STI intervention strategies

Evaluating the Perception of Luxury Brands in Today\u27s Marketplace and the Impact of the Digital Age on these Brands

“In spite of the global recession, luxury seems to be everywhere. Luxury is a term that is routinely used in our everyday life: a promise of decadence and a dream of an exclusive lifestyle, a key component of marketing management and a tagline in commercials and advertising campaigns…However, what does luxury really mean? The only consensus on the meaning of luxury is that there is little consensus” (Hennigs et al. 3). For an industry that once presented itself as so exclusive and definitive, it is hard to believe there is such uncertainty in defining this market. Much of this ambiguity can be contributed to the impact of globalization and conglomeration that previously impacted the economy, as well as trends in brand and product extensions. Regardless of how or why this industry evolved, a definitive consensus can be made that the luxury brand industry is different than it once was. However, as one can imagine, the understanding of consumers’ perceptions regarding luxury brands is key for creating appropriate strategies. Consumers’ varying perceptions towards luxury brands creates many questions in regards to what trait or traits really define a brand as “luxury”. Is it the price, the quality, the brand’s history or some other indicator that identifies a brand as a luxurious one to consumers? Furthermore, there tends to be hypocrisy in consumers’ perceptions towards luxury brands. In regards to consumers’ attitudes towards the concept of luxury, The Journal of Business & Economics Research claims “they are ambivalent across and within consumers, as consumer behavior is inconsistent with self-reported attitudes, as consumers can’t understand their own contradictions” (Stegemann 61). In addition to marketers’ struggle to understand what consumers perceive as a luxury brand, the impact of technology and the digital age has only enhanced the subject matter. Luxury brands that once prided themselves on premier customer service and providing a sort of “white –glove” experience for their customers, must be flexible and accepting in their marketing strategies or face the fear of abandonment. The consumer of today’s world not only views luxury brands differently but also shops differently. Instant gratification is a concept that has become prevalent in consumers buying habits and must be noted by marketers. As the European Financial Review recognizes “Luxury is everywhere”, and the fact of the matter is that these luxury brands must come to terms with today’s world of E-commerce (Hennigs 2). It is necessary to understand how consumers view luxury brands as well as their routine purchase habits, because these perceptions and preferences will be essential in establishing marketing strategies that ensure loyal customers

Welfare Time Limits: An Update on State Policies, Implementation, and Effects on Families

One of the most controversial features of the 1990s welfare reforms was the imposition of time limits on benefit receipt. This comprehensive review, written by The Lewin Group and MDRC, includes analyses of administrative data reported by states to the federal government, visits to several states, and a literature review

Mary Van Turner Scrapbook 6

Undated photo album of Mary Van Turner (Class of 1927), daughter of Joseph Turner and niece of Erich Rath. Photos are of Turner and possible family and friends. A date of 1927 (year of Turner\u27s graduation) is being used as a placeholder for an unknown date. Some photos are likely from later in her life.https://digitalcommons.hollins.edu/scrapbooks/1045/thumbnail.jp

Mary Van Turner Scrapbook 3

This digital archive includes scrapbooks without abridgement or exclusions. Images contained in the digital archives and in the original scrapbooks may contain pictures or content that is offensive and is not condoned by the University. We maintain the full contents these scrapbooks for historical accuracy. Undated photo album of Mary Van Turner (Class of 1927), daughter of Joseph Turner and niece of Erich Rath. Scrapbook consists of photos of a horse racing event, New York City, and a couple photos of Hollins buildings. A date of 1927 (year of Turner\u27s graduation) is being used as a placeholder for an unknown date.https://digitalcommons.hollins.edu/scrapbooks/1041/thumbnail.jp