8,987 research outputs found

    Skyrmions in the Moore-Read state at nu=5/2

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    We study charged excitations of the non-abelian Moore-Read liquid at filling factor nu=5/2, allowing for spin depolarization. Using a combination of numerical studies, and taking account of non-zero well widths, we find that at sufficiently low Zeeman energy it is energetically favourable for charge e/4 quasiholes to bind into "skyrmions" of charge e/2. We show that skyrmion formation is further promoted by disorder, and argue that this can lead to a depolarized nu=5/2 ground state in realistic experimental situations. We comment on the consequences for the activated transport.Comment: 4 pages, 3 figure

    Population studies on Phytophthora infestans on potatoes and tomatoes in southern Germany

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    Fifty-seven isolates of Phytophthora infestans from blighted potato foliage were collected in 1995 in southern Germany and analysed for mating type and sensitivity to metalaxyl. Fifty-six of them were characterised as A1 and one as A2 mating types. Resistance to metalaxyl was observed frequently: 53 isolates were resistant, three were partially sensitive, and one was sensitive. In a subsequent field study in 1999, 84 isolates collected from blighted potato and tomato foliage were analysed for mating type. Seventy-two were characterised as A1 and twelve as A2 mating types. The response of 76 isolates to metalaxyl and to propamocarb was tested. The majority (42) of the 76 isolates was classified as resistant to metalaxyl; 31 were partially sensitive and only three isolates were sensitive. The results with propamocarb were less discrete; 10 isolates were classified as resistant and three were clearly sensitive. AFLP fingerprinting was used to examine the genetic structure of the southern German P. infestans population collected in 1999 and indicated that the tested population can be sub-divided into a tomato group, a potato group and a mixed group containing isolates collected from both crops. The presence of Ia and IIa mitochondrial DNA haplotypes indicates that the German P. infestans isolates belong to the new pathogen population that has also been reported in neighbouring regions of Europe. The present study indicates that at the beginning of the season only a few genotypes were present, and the population became genetically more variable at the end of the growing season

    The role of quality of life surveys in managing change in democratic transitions: the South African case

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    The South African Quality of Life Project has tracked subjective well-being, life satisfaction and happiness, since the early eighties at the national level. In most democratic countries around the globe, the average citizen says he or she is satisfied with life in general. In South Africa this is not the case. Since the early 1980s, the trend study shows up disparities between one sector of the South African population that is satisfied with life in general and various aspects of life and another sector that is very dissatisfied. Generally, the better-off report higher levels of satisfaction and happiness than the worse-off. The most plausible explanation for the South African quality-of-life constellation is the huge gap in living standards between rich and poor, a legacy of the apartheid era, which discriminated against blacks and to a lesser extent against Indian and coloured people. Euphoria following on the first democratic elections in April 1994, which registered equally high aggregate levels of happiness and life satisfaction among all sectors of the population, was short-lived. Under democracy, expectations “for a better life for all”, the election slogans for the 1994 and 1999 general elections, has risen. South Africa has one of the most enlightened constitutions, which guarantees basic human rights and supports advancement of the previously disadvantaged. As long as South Africans perceive barriers to accessing the material rewards of democracy, they do not see justice has been done. South Africa is currently grappling with problems common to other societies in transition to democracy. Since 1994, government programmes and policies have been devised to address the critical twin problems of poverty and inequality in society. The latest round of research for the South African Quality of Life Trends Project probes popular assessments of the policies and programmes aimed at improving the quality of life of ordinary South Africans. Interviews with a panel of 25 opinion leaders in the run-up to the June 1999 general elections were followed by a nationally representative opinion survey in October 1999. The paper outlines the role of social indicators in monitoring quality of life in South Africa and reports findings from the elite and rank-and-file surveys. Generally, the winners and losers in the new political dispensation see changes from a different perspective. The disadvantaged are more likely to have seen material gains and recommend increased delivery of services and opportunities for social mobility. The advantaged, who have mainly experienced non-material or no gains since 1994, are more likely to be pessimistic about the future. It is concluded that the groundswell of optimism will sustain the majority of South Africans who are still dissatisfied with life until their dreams of the good life are fulfilled

    Looking after your ground: resource management practice by Rakiura Maori Titi harvesters

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    The annual harvest of Titi, Puifinus griseus, on islands adjacent to Rakiura (Stewart Island) by Rakiura Maori is one of the last large-scale customary uses of native wildlife in New Zealand. This study investigates whether Rakiura Maori harvesting practices constitute common property resource management and how these practices relate to the sustainability of Titi harvests. Semi-directive interviews were conducted with 20 experienced Titi harvesters and elders to record their matauranga Maori (Traditional Ecological Knowledge) and tikanga (lore) that govern this harvest. Access to the resource is shared and controlled by birthright. Informal and formal sanctions enforce the rules that promote sustainable use by protecting island habitat and adult birds, and minimising disturbance. These rules and other aspects of Titi harvesting practice conform to common property resource management theory. While adhering to the main resource rules, localised flexibility in management provides harvesters with the ability to adapt to changing environmental and social circumstances. Adaptive co-management of Titi harvesting has included turning lore into law to reinforce social institutions, integration of science and matauranga for sustainability assessments, and application of new ecosystem management tools. Environmentality is promoted by local self-government of Rakiura Maori Titi harvesting practice and island ecosystem management

    South Africa's `Rainbow People', national pride and optimism: a trend study

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    Since the first democratic elections of 1994, South Africans are popularly known as the ‘rainbow people'. The paper reports the acceptance of the rainbow as political symbol of unity among the diverse people of South Africa at three times: Immediately after the 1994 elections, two years later in 1996, and five years later in 1999 after the second general elections. The database for the study are responses to items placed with a syndicated national survey conducted countrywide. The public discourse on the rainbow is reviewed through personal interviews with a panel of 25 elites contacted in the run-up to the second general elections. The researchers revisit conclusions based on the earlier results (Mþller, Dickow and Harris, 1999). The third round of research finds that the appeal of the rainbow as political symbol has waned but is still inclusive of all groups in society. Projections of national pride have shifted from the rainbow as symbol of unity and reconciliation to other icons of achievement such as the Reconstruction and Development Programme and prowess in sport. Support for the political symbolism of the rainbow is positively associated with happiness, life satisfaction and optimism. Lack of a focus of national pride is associated with pessimism. Results support the conclusion reached earlier that belief in the `rainbow nation' ideal boosts optimism and promotes happiness during South Africa's transition to a stable democracy, thereby preventing alienation among the losers under the new political dispensation. Linkages between acceptance of the rainbow symbol, subjective well-being and optimism are discussed in the light of the socio-political changes which have taken place in South Africa since democracy

    Measuring health-related quality of life: a comparison between people living with AIDS and police on active duty: research

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    The escalating rate of AIDS-related deaths in South Africa has led to an increase in social scientific research on the perceptions and experiences of people suffering from AIDS by focusing on their physical health and emo- tional well-being. The aim of this study was to measure and compare the quality of life of two sample groups in South Africa, namely members of the police on active duty, as an example of a healthy population, and people living with AIDS. The SF-36 questionnaire was used as measuring instrument to assess the respondents(tm) perceptions of their own health-related quality of life. From the research, which was based on a comparative approach, it was found that statistically significant differences existed between people living with AIDS and members of the police force in respect of their scores on all eight of the SF-36 domains (p < 0.05). The biggest difference between the AIDS respondents and members of the police occurred in the emotional roles limitation dimension, followed by the physical functioning and the bodily pain dimensions. Intervention programmes that are aimed at contributing to the improvement of the well-being of people suffering from AIDS, therefore need to incorporate mechanisms that provide support in all eight of the quality-of-life dimensions. Die styging in die getal VIGS-verwante sterftes in Suid-Afrika het gelei tot 'n toename in sosiaalwetenskaplike navorsing oor die persepsies en belewenisse van mense met VIGS, met die fokus op hul fisieke gesondheid en emosionele welsyn. Die doel van hierdie studie was om die lewenskwaliteit van twee groepe in Suid-Afrika te meet en met mekaar te vergelyk. Hierdie twee groepe het enersyds uit lede van die polisie in aktiewe diens, as voorbeeld van (tm)n gesonde populasie en andersyds uit mense met VIGS bestaan. Die SF-36-vraelys is as meetinstrument gebruik om die respondente se persepsies van hul gesondheidsverwante lewenskwaliteit te assesseer. Op grond van hierdie navorsing, wat op (tm)n vergelykende benadering berus het, is bevind dat mense met VIGS en lede van die polisiemag se onderskeie tellings op al agt SF-36-domeine (p < 0.05) beduidend verskil het. Die grootste verskil tussen die persepsies van die respondente met VIGS en di&#3619;&#3593; van lede van die polisiemag het op die emosionele rolbeperkingsdomein gel&#3619;&#3594;, gevolg deur die domeine van fisieke funksionering en liggaamlike pyn. Dit is dus noodsaaklik dat intervensieprogramme wat die welsyn van VIGS-lyers wil bevorder, meganismes moet inkorporeer wat ondersteuning in al agt lewenskwaliteitsdomeine bied. Health SA Gesondheid Vol.9(2) 2004: 31-4

    South Africa's "Rainbow People", national pride and happiness

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    Since the first free elections were held in April 1994, South Africans are popularly known as the ''rainbow people''. The paper inquires whether South Africans who experienced pride in their nation in the first years of democracy also perceived a greater sense of subjective well-being. It is proposed that national pride in post-apartheid South Africa might be fused with or work through self-esteem to lift levels of happiness. The paper traces the history of the new integrating civil religion of the rainbow people and the acceptance of the rainbow as a political symbol of unity among the diverse people of South Africa immediately after the 1994 elections and two years later. The proposed link between national pride and happiness was explored with data from two independent national surveys, the 1995 South African World Values Survey conducted by Markinor and a June 1996 MarkData syndicated omnibus survey. The study found that the appeal of the rainbow as political symbol was inclusive of all groups in society and that feelings of national pride and support for the rainbow ideal were positively associated with subjective well-being. As indicated by intensity and frequency measures, the majority of South Africans were proud of their country and could name a national achievement that inspired pride. Better-off South Africans tended to be happier and more satisfied with life but less proud, while the poor were less happy but fiercely proud of their country. Results suggest that belief in South Africa’s ''rainbow nation'' ideal may have assisted in boosting happiness during the transition to a stable democracy, thereby preventing alienation among the losers under the new political dispensation. Supporters of the ideal of the rainbow nation were more optimistic than others about the future of their country
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