593 research outputs found

    Cusp forms, Spanning sets and Super Symmetry

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    - Construction of a spanning set for the space of cusp forms in the case of a product of complex symmetric domains of rank 1 and a discrete subgroup with compact quotient based on the concept of hyperbolic flows, - formulating the theory of super automorphic forms for parametrized discrete subgroups, - construction of a spanning set for the space of super cusp forms in the rank 1 case for non-parametrized discrete subgroups, - outlook on how to define the space of super cusp forms and how to find spanning sets in the case of a parametrized discrete subgroup

    Association Between Genetic Variation in FOXO3 and Reductions in Inflammation and Disease Activity in Inflammatory Polyarthritis.

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    OBJECTIVE: Genetic variation in FOXO3 (tagged by rs12212067) has been associated with a milder course of rheumatoid arthritis (RA) and shown to limit monocyte-driven inflammation through a transforming growth factor β1-dependent pathway. This genetic association, however, has not been consistently observed in other RA cohorts. We sought to clarify the contribution of FOXO3 to prognosis in RA by combining detailed analysis of nonradiographic disease severity measures with an in vivo model of arthritis. METHODS: Collagen-induced arthritis, the most commonly used mouse model of RA, was used to assess how Foxo3 contributes to arthritis severity. Using clinical, serologic, and biochemical methods, the arthritis that developed in mice carrying a loss-of-function mutation in Foxo3 was compared with that which occurred in littermate controls. The association of rs12212067 with nonradiographic measures of RA severity, including the C-reactive protein level, the swollen joint count, the tender joint count, the Disease Activity Score in 28 joints, and the Health Assessment Questionnaire score, were modeled longitudinally in a large prospective cohort of patients with early RA. RESULTS: Loss of Foxo3 function resulted in more severe arthritis in vivo (both clinically and histologically) and was associated with higher titers of anticollagen antibodies and interleukin-6 in the blood. Similarly, rs12212067 (a single-nucleotide polymorphism that increases FOXO3 transcription) was associated with reduced inflammation, both biochemically and clinically, and with lower RA activity scores. CONCLUSION: Consistent with its known role in restraining inflammatory responses, FOXO3 limits the severity of in vivo arthritis and, through genetic variation that increases its transcription, is associated with reduced inflammation and disease activity in RA patients, effects that result in less radiographic damage.Arthritis Research UK (Grant ID: 20385)This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/art.3976

    The life history of selected coastal foredune species of South Africa

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    South African dune fields are severely threatened by human expansion and in the long run the stabilisation of many dunes will be necessary. The alien grass Ammophila arenaria is the most important drift sand stabiliser at present in South Africa. Although not invasive, the current impact of A. arenaria on the dune systems of South Africa is considerable, and thus the stabilising benefit of the grass seemed to may be outweighed by its negative consequences. It is therefore preferable to use indigenous sand stabilising species. In order to define guidelines for the application of indigenous plants for stabilisation, their autecology should be studied first to enhance the chance of successful stabilisation results. The main aim of the present thesis was to gather information on the life history processes of selected indigenous, sand stabilising foredune species. To investigate the growth of foredune pioneer species, the common pioneer Scaevola plumieri was followed over a three-year period to determine the growth season and leaf phenology. Soil-borne pathogens are known to influence the growth and vegetation dynamics of foredune species. To examine this effect on the South African foredunes the rhizosphere soil and the roots of several species were studied. To test the effect of the nematode fauna on succeeding plant species a transplantation experiment was carried out. The seed stage is the only life-cycle stage that can survive unfavourable conditions. Therefore, the seed ecology of several foredune species was studied extensively to determine the reproductive season, the seed production, the fate of seeds after shedding (germination, seawater dispersal), germination requirements and seed bank strategy. Seeds of the species Arctotheca populifolia, Ipomoea pes-caprae, Myrica cordifolia, and Scaevola plumieri were subjected to germination trials, field observations on seedling survival, and scarification and stratification experiments. This was done to obtain information about the germination requirements and to determine the reproductive season and growth season. The seed bank strategy of the foredune species, as well as the seed bank density, was determined by extensive sampling along the Cape coast. The species S. plumieri thrived under sand accretion situations, which makes it a good candidate for stabilisation purposes. The growth of S. plumieri was seasonal, with the highest leaf production during spring and summer. The stem position on the foredune had a strong effect on the overall performance of S. plumieri , with the stems situated on the landward face of the foredune showing higher leaf and seed production. Theiii nematode survey of soil and roots of several foredune species showed that all plant species featured a specific nematode fauna in the rhizosphere soil and the roots. The specific nematode fauna affected the growth of foreign plant species in the transplantation experiment, resulting in a lower root and/or shoot biomass production. Most of the foredune species produce seeds from spring to late summer. For S. plumieri the position of the stem on the dunes, as well as the predation of unripe seeds affected the number of seeds produced. The highest production was found for the landward faced stems. The S. plumieri seeds were able to float on seawater for at least three months without losing viability, as was observed for seeds of I. pes-caprae. The seeds of M. cordifolia, however, sank after a few days, but their viability was not affected. The rhizome fragments of A. arenaria and S. virginicus floated for 120 days, whereas the fragments of E. villosa sunk after one day. The viability of S. virginicus fragments was affected by the duration in seawater by an increase in sprouting time. The seeds of all species tested germinated readily under controlled conditions, except S. plumieri seeds which required a long lag-phase before germination. In the field the seeds of A. populifolia, I. pes-caprae and S. plumieri germinated, producing many seedlings. Only the seedlings of A. populifolia and S. plumieri survived. Of the species found in the foredunes 57% was represented in the soil seed bank. For most species, the seeds that were found in the seed bank showed viability of at least 40%. Many of the seeds found were older than one year, suggesting a short-term persistent seed bank. The present study is a start in filling the gap in information on dune pioneer and foredune species. The conclusion was that in general all species in the present study were easy to grow under controlled conditions, and thus could be used for stabilisation purposes. When the more rapidly growing pioneer species are planted in combination with succeeding foredune species, a functional and aesthetic ecosystem could be created
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