314 research outputs found

    An experiment in hurricane track prediction using parallel computing methods

    Get PDF
    The barotropic model is used to explore the advantages of parallel processing in deterministic forecasting. We apply this model to the track forecasting of hurricane Elena (1985). In this particular application, solutions to systems of elliptic equations are the essence of the computational mechanics. One set of equations is associated with the decomposition of the wind into irrotational and nondivergent components - this determines the initial nondivergent state. Another set is associated with recovery of the streamfunction from the forecasted vorticity. We demonstrate that direct parallel methods based on accelerated block cyclic reduction (BCR) significantly reduce the computational time required to solve the elliptic equations germane to this decomposition and forecast problem. A 72-h track prediction was made using incremental time steps of 16 min on a network of 3000 grid points nominally separated by 100 km. The prediction took 30 sec on the 8-processor Alliant FX/8 computer. This was a speed-up of 3.7 when compared to the one-processor version. The 72-h prediction of Elena's track was made as the storm moved toward Florida's west coast. Approximately 200 km west of Tampa Bay, Elena executed a dramatic recurvature that ultimately changed its course toward the northwest. Although the barotropic track forecast was unable to capture the hurricane's tight cycloidal looping maneuver, the subsequent northwesterly movement was accurately forecasted as was the location and timing of landfall near Mobile Bay

    A vaccine that prevents pregnancy in women

    Get PDF
    We report here results of clinical trials on a birth control vaccine, consisting of a heterospecies dimer of the beta subunit of human chorionic gonadotropin (hCG) associated noncovalently with the alpha subunit of ovine luteinizing hormone and conjugated to tetanus and diphtheria toxoids as carriers, that induces antibodies of high avidity (K(a) approximately 10(10) M-1) against hCG. Fertile women exposed to conception over 1224 cycles recorded only one pregnancy at antibody titers of > 50 ng/ml (hCG bioneutralization capacity). The antibody response declines with time; fertility was regained when titers fell to < 35 ng/ml. This study presents evidence of the feasibility of a vaccine for control of human fertility

    Assessment of burn wound tissue in situ by multiphoton microscopy employing fluorescence and second harmonic generation contrasts in live animals

    Get PDF
    Current assessment of burn wound depth and progression of healing for proper choice of treatment is based on time-consuming and invasive techniques that may interfere with the healing process. One way to overcome these problems is to use noninvasive techniques. We use multiphoton microscopy (MPM) that employs fluorescence and second harmonic generation (SHG) contrasts to noninvasively follow the burn healing process in situ as healing progresses in live animals. Healing progression was followed in a partial thickness burn wound made on the dorsum of anesthetized Sprague-Dawley rats with a 2.8 cm diameter brass cylinder heated at 80oC for 60 seconds and pressed against the shaved rat skin for 6 seconds. During the first five days, burn healing was characterized by changes in the organization of collagen into a compact, mat-like assembly, suggesting progressive degradation of collagen within the injury site.We also detected increased follicular cell damage and a strong auto-fluorescence signal from cellular debris. Deposition of new collagen was seen after the scab fell off and gradually increased thereafter as detected with an increase in the SHG signal intensity. A great increase in the density of cells was observed as well. From day 21 on, a network of capillaries with blood flow was observed. The epidermal cell layer and the blood vessel network became progressively more organized. At day 29, fibrillar collagen had SHG signal levels and morphology of the nearly preburn state. These findings were corroborated by histology/histochemistry. In conclusion, MPM technology that employs fluorescence and SHG contrasts is instrumental in following the healing process, in particular during the early stages of healing. The degree and rate with which these events occur early after burning could help clinicians make treatment decisions. The outcomes of healing at later times would be indicative of the effectiveness of the treatment applied

    Extended Scaling in High Dimensions

    Get PDF
    We apply and test the recently proposed "extended scaling" scheme in an analysis of the magnetic susceptibility of Ising systems above the upper critical dimension. The data are obtained by Monte Carlo simulations using both the conventional Wolff cluster algorithm and the Prokof'ev-Svistunov worm algorithm. As already observed for other models, extended scaling is shown to extend the high-temperature critical scaling regime over a range of temperatures much wider than that achieved conventionally. It allows for an accurate determination of leading and sub-leading scaling indices, critical temperatures and amplitudes of the confluent corrections.Comment: 16 pages, 8 figures. Improved version to appear in JSTA

    Imaging response assessment for CNS germ cell tumours: consensus recommendations from the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group

    Get PDF
    Homogeneous and common objective disease assessments and standardised response criteria are important for better international clinical trials for CNS germ cell tumours. Currently, European protocols differ from those of North America (the USA and Canada) in terms of criteria to assess radiological disease response. An international working group of the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group was therefore established to review existing literature and current practices, identify major challenges regarding imaging assessment, and develop consensus recommendations for imaging response assessment for patients with CNS germ cell tumours. New clinical imaging standards were defined for the most common sites of CNS germ cell tumour and for the definition of locoregional extension. These new standards will allow the evaluation of response to therapy in patients with CNS germ cell tumours to be more consistent, and facilitate direct comparison of treatment outcomes across international studies

    Inhaled levodopa in Parkinson's disease patients with OFF periods: A randomized 12-month pulmonary safety study

    Get PDF
    Introduction: CVT-301 is an orally inhaled levodopa therapy approved for the intermittent treatment of OFF episodes in Parkinson's disease patients who are taking a standard oral levodopa regimen. This open-label, randomized, controlled study over 12 months characterizes the safety, including pulmonary safety, of CVT-301 84 mg (nominal respirable levodopa fine-particle dose, 50 mg). Methods: Patients experiencing motor fluctuations were randomized 2:1 to CVT-301 or an observational cohort (OC) receiving oral standard of care. Pulmonary safety was assessed using spirometry and carbon monoxide diffusion capacity (DLCO). Exploratory efficacy endpoints, assessed only for CVT-301, included change in Unified Parkinson's Disease Rating Scale Part III (UPDRS-III), patients achieving ON within 60 min and remaining ON at 60 min, Patient Global Impression of Change (PGIC) scale, and total daily OFF time. Results: Of 408 patients randomized, 310 completed the study (204 in CVT-301 and 106 in OC). Mean 12-month changes from baseline for CVT-301 were −0.105 L (FEV1) and −0.378 mL/min/mm Hg (DLCO), and for OC were −0.117 L and −0.722 mL/min/mm Hg, respectively. Between-group comparisons were not statistically significant. For FEV1/FVC the 12-month change was −0.3 and −1.6, respectively, which was a significant between-group difference. However, between-group differences were not significant at 3 and 9 months and all changes from baseline were small (<2.0%). UPDRS-III scores improved from predose to 60 min postdose at all assessments; 80%–85% of patients switched ON within 60 min and remained ON; and >75% reported improvement in PGIC. OFF time decreased by 1.32–1.42 h/day. Conclusion: CVT-301 84 mg induced no clinically significant differences in pulmonary function compared with the OC. Improvements in motor scores, OFF time, and patient-reported outcomes support clinical efficacy for up to 12 months

    Inappropriate prescribing and adverse drug events in older people

    Get PDF
    Inappropriate prescribing (IP) in older patients is highly prevalent and is associated with an increased risk of adverse drug events (ADEs), morbidity, mortality and healthcare utilisation. Consequently, IP is a major safety concern and with changing population demographics, it is likely to become even more prevalent in the future. IP can be detected using explicit or implicit prescribing indicators. Theoretically, the routine clinical application of these IP criteria could represent an inexpensive and time efficient method to optimise prescribing practice. However, IP criteria must be sensitive, specific, have good inter-rater reliability and incorporate those medications most commonly associated with ADEs in older people. To be clinically relevant, use of prescribing appropriateness tools must translate into positive patient outcomes, such as reduced rates of ADEs. To accurately measure these outcomes, a reliable method of assessing the relationship between the administration of a drug and an adverse clinical event is required. The Naranjo criteria are the most widely used tool for assessing ADE causality, however, they are often difficult to interpret in the context of older patients. ADE causality criteria that allow for the multiple co-morbidities and prescribed medications in older people are required. Ultimately, the current high prevalence of IP and ADEs is unacceptable. IP screening criteria need to be tested as an intervention to assess their impact on the incidence of ADEs in vulnerable older patients. There is a role for IP screening tools in everyday clinical practice. These should enhance, not replace good clinical judgement, which in turn should be based on sound pharmacogeriatric training
    • …
    corecore