788 research outputs found

    Development of Great Lakes algorithms for the Nimbus-G coastal zone color scanner

    Get PDF
    A series of experiments in the Great Lakes designed to evaluate the application of the Nimbus G satellite Coastal Zone Color Scanner (CZCS) were conducted. Absorption and scattering measurement data were reduced to obtain a preliminary optical model for the Great Lakes. Available optical models were used in turn to calculate subsurface reflectances for expected concentrations of chlorophyll-a pigment and suspended minerals. Multiple nonlinear regression techniques were used to derive CZCS water quality prediction equations from Great Lakes simulation data. An existing atmospheric model was combined with a water model to provide the necessary simulation data for evaluation of the preliminary CZCS algorithms. A CZCS scanner model was developed which accounts for image distorting scanner and satellite motions. This model was used in turn to generate mapping polynomials that define the transformation from the original image to one configured in a polyconic projection. Four computer programs (FORTRAN IV) for image transformation are presented

    Verification of reflectance models in turbid waters

    Get PDF
    Inherent optical parameters of very turbid waters were used to evaluate existing water reflectance models. Measured upwelling radiance spectra and Monte Carlo simulations of the radiative transfer equations were compared with results from models based upon two flow, quasi-single scattering, augmented isotropic scattering, and power series approximation. Each model was evaluated for three separate components of upwelling radiance: (1) direct sunlight; (2) diffuse skylight; and (3) internally reflected light. Limitations of existing water reflectance models as applied to turbid waters and possible applications to the extraction of water constituent information are discussed

    Dielectronic Recombination of Ground-State and Metastable Li+ Ions

    Get PDF
    Dielectronic recombination has been investigated for Delta-n = 1 resonances of ground-state Li+(1s^2) and for Delta-n = 0 resonances of metastable Li+(1s2s ^3S). The ground-state spectrum shows three prominent transitions between 53 and 64 eV, while the metastable spectrum exhibits many transitions with energies < 3.2 eV. Reasonably good agreement of R-matrix, LS coupling calculations with the measured recombination rate coefficient is obtained. The time dependence of the recombination rate yields a radiative lifetime of 52.2 +- 5.0 s for the 2 ^3S level of Li+.Comment: Submitted to Phys. Rev. A; REVTeX, 4 pages, 3 figure

    Quality of life in patients with a perineal hernia

    Get PDF
    Introduction: Patients who develop a perineal hernia after abdominoperineal resection may experience discomfort during daily activities and urogenital dysfunction, but the impact on quality of life has never been formally assessed. Materials and methods: Patients who underwent abdominoperineal resection for rectal cancer between 2014 and 2022 in two prospective multicenter trials were included. Primary outcome was defined as median overall scores or scores on functional and symptom scales of the following quality of life questionnaires: 5-level version of the 5-dimensional EuroQol, Short Form-36, and European Organization for Research and Treatment of Cancer QoL Questionnaire Colorectal cancer 29 and 30, Urogenital Distress Inventory-6, Incontinence Impact Questionnaire-7. Results: Questionnaires were available in 27 patients with a perineal hernia and 62 patients without a perineal hernia. The 5-dimensional EuroQol score was significantly lower in patients with a perineal hernia (83 vs 87, p = 0.048), which implies a reduced level of functioning. The median scores of pain-specific domains were significantly worse in patients with a perineal hernia as measured by the SF-36 (78 vs. 90, p = 0.006), the EORTC-CR29 (17 vs. 11, p=&lt;0.001) and EORTC-C30 (17 vs. 0, p = 0.019). Also, significantly worse physical (73 vs. 100, p = 0.049) and emotional (83 vs. 100, p = 0.048) functioning based on EORTC-C30 was observed among those patients. Minimally important differences were found for role, physical and social functioning of the SF-36 and EORTC-C30. The urological function did not differ between the groups. Conclusion: A symptomatic perineal hernia can significantly worsen quality of life on several domains, indicating the severity of this complication.</p

    Phase I study of gemcitabine using a once every 2 weeks schedule.

    Get PDF
    Gemcitabine (2',2'-difluorodeoxycytidine) is a novel nucleoside analogue. As part of a series of studies to determine the maximum tolerated dose (MTD) of gemcitabine and the most appropriate schedule, a two-centre phase I study of gemcitabine was undertaken in patients with advanced refractory solid tumours using a once every 2 weeks schedule. Fifty-two patients were entered into the study at 14 different dose levels (40-5700 mg m-2). Weekly evaluations for toxicity were performed and the MTD for this once every 2 weeks schedule was 5700 mg m-2. The dose-limiting toxicity was myelosuppression, with neutropenia being most significant. Other toxicities were nausea, vomiting, fever and asthenia. One minor response was seen in a heavily pretreated breast cancer patient treated at 1200 mg m-2. Preclinical studies suggest that the efficacy of gemcitabine is more schedule than dose related, and it is concluded that this is not the most appropriate dosing schedule for gemcitabine. However, this study demonstrates the safety profile of gemcitabine, as doses over fourfold greater than that recommended for the weekly schedule of 1000 mg m-2 could be tolerated
    corecore