5,223 research outputs found

    Differentiating apple sports by pollen ultrastructure : a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticultural Science at Massey University

    Get PDF
    Cultivars are plants that form distinct, uniform and stable phenotypes. New cultivars can be protected by Plant Variety Rights (PVR) which allow the owner exclusive rights to the propagation and sale of the plant material. Current PVR identification methods for apple cultivars require detailed records of tree, flower and fruit characteristics to differentiate the new cultivars from known cultivars. This method is slow, expensive and unable to cope with the increasing numbers of sports. Biochemical identification methods such as isozymes, restriction fragment length polymerisation (RFLP), random amplified polymorphism DNAs (RAPD), and minisatellite probes, can quickly and objectively differentiate cultivars, but cannot differentiate apple sports. Previous research suggested that pollen ultrastructure could be an alternative method for plant identification. This thesis is concerned with the development of a technique to differentiate apple sports using pollen exine patterns. Scanning electron microscopy was used to capture images of the apple pollen grain and the exine surface. A digital image analysis algorithm was developed to extract quantitative data from the pollen grain dimensions and pore characteristics, and a Fast Fourier transform extracted quantitative data from the ridge patterns. Statistical methods were applied to the data to differentiate the sports. Pollen harvested from apple flowers in the spring were wider than pollen harvested from flowers forced out of season under artificial conditions. Significant differences between trees were found for pollen grain length:width ratio, percent pore coverage, pore area and pore length but further research is required. However, apple cultivars types 'Red Delicious' and 'Gala' were successfully differentiated by pore and pollen grain variables, and 'Aversang' and 'Ultrared' sports of 'Red Delicious', and 'Splenola' and 'Galalea' sports Of 'Gala' were successfully differentiated by exine ridge patterns and pollen grain measurements. Differentiation of apple sports by pollen requires further development but may be one of the only quick, objective identification methods that can differentiate sports. Sport differentiation would greatly aid PVR establishment and enforcement

    Hospitals, Managed Care, and the Charity Caseload in California

    Get PDF
    Many observers have blamed HMOs for increasing financial pressures on private hospitals and causing them to cut back on the provision of charity care. We examine this issue using data on all hospital discharges in California between 1988 and 1996. We find that public hospitals in counties with higher HMO penetration do take on a larger share of the county's charity caseload. However, these public hospitals also take on larger shares of most other types of patients. At the hospital level, we find little evidence that either for-profit or non-profit private hospitals respond to HMO penetration by turning away uninsured and Medicaid patients. On the contrary, in the for-profit sector higher HMO penetration is linked to reductions in the share of privately insured patients in the caseload, and corresponding increases in the share of Medicare patients and Medicaid births. Since HMO penetration reduces the price paid by privately insured patients they may be less attractive to for-profit hospitals relative to the publicly insured.

    Transfer

    Get PDF

    Insomnia

    Full text link

    For Aneas Murphy

    Get PDF

    A Resume of Beliefs

    Get PDF

    Alien Registration- Currie, John (Houlton, Aroostook County)

    Get PDF
    https://digitalmaine.com/alien_docs/36239/thumbnail.jp

    Alien Registration- Currie, John T. (Wade, Aroostook County)

    Get PDF
    https://digitalmaine.com/alien_docs/32681/thumbnail.jp

    Absorption heat recovery

    Get PDF
    • 

    corecore