185 research outputs found

    Yield Monitoring and Mapping

    Get PDF
    The monitoring and mapping of yield variations have captured the interest of many producers. The ability to monitor grain yield on-the-go and map the in-field variations for use in management decisions has come from a dream to near-reality. The paper and presentation will discuss the recent past, the present, and the near future of crop yield monitoring and mapping. An attempt to provide accurate, correct, and current information was made. However, some information may have changed and may be outdated. This paper is not an endorsement of the products or technologies

    Continuum-particle hybrid coupling for mass, momentum and energy transfers in unsteady fluid flow

    Full text link
    The aim of hybrid methods in simulations is to communicate regions with disparate time and length scales. Here, a fluid described at the atomistic level within an inner region P is coupled to an outer region C described by continuum fluid dynamics. The matching of both descriptions of matter is made across an overlapping region and, in general, consists of a two-way coupling scheme (C->P and P->C) which conveys mass, momentum and energy fluxes. The contribution of the hybrid scheme hereby presented is two-fold: first it treats unsteady flows and, more importantly, it handles energy exchange between both C and P regions. The implementation of the C->P coupling is tested here using steady and unsteady flows with different rates of mass, momentum and energy exchange. In particular, relaxing flows described by linear hydrodynamics (transversal and longitudinal waves) are most enlightening as they comprise the whole set of hydrodynamic modes. Applying the hybrid coupling scheme after the onset of an initial perturbation, the cell-averaged Fourier components of the flow variables in the P region (velocity, density, internal energy, temperature and pressure) evolve in excellent agreement with the hydrodynamic trends. It is also shown that the scheme preserves the correct rate of entropy production. We discuss some general requirements on the coarse-grained length and time scales arising from both the characteristic microscopic and hydrodynamic scales.Comment: LaTex, 12 pages, 9 figure

    Molecular Dynamics Simulation of Compressible Fluid Flow in Two-Dimensional Channels

    Full text link
    We study compressible fluid flow in narrow two-dimensional channels using a novel molecular dynamics simulation method. In the simulation area, an upstream source is maintained at constant density and temperature while a downstream reservoir is kept at vacuum. The channel is sufficiently long in the direction of the flow that the finite length has little effect on the properties of the fluid in the central region. The simulated system is represented by an efficient data structure, whose internal elements are created and manipulated dynamically in a layered fashion. Consequently the code is highly efficient and manifests completely linear performance in simulations of large systems. We obtain the steady-state velocity, temperature, and density distributions in the system. The velocity distribution across the channel is very nearly a quadratic function of the distance from the center of the channel and reveals velocity slip at the boundaries; the temperature distribution is only approximately a quartic function of this distance from the center to the channel. The density distribution across the channel is non-uniform. We attribute this non-uniformity to the relatively high Mach number, approximately 0.5, in the fluid flow. An equation for the density distribution based on simple compressibility arguments is proposed; its predictions agree well with the simulation results. Validity of the concept of local dynamic temperature and the variation of the temperature along the channel are discussed.Comment: 16 pages (in latex) + 8 figures (in a single ps file). Submitted to the Physical Review

    Monte Carlo study of the Widom-Rowlinson fluid using cluster methods

    Full text link
    The Widom-Rowlinson model of a fluid mixture is studied using a new cluster algorithm that is a generalization of the invaded cluster algorithm previously applied to Potts models. Our estimate of the critical exponents for the two-component fluid are consistent with the Ising universality class in two and three dimensions. We also present results for the three-component fluid.Comment: 13 pages RevTex and 2 Postscript figure

    Randomly sampling maximal itemsets

    Full text link

    Clinical practice guideline on the optimal radiotherapeutic management of brain metastases

    Get PDF
    BACKGROUND: An evidence-based clinical practice guideline on the optimal radiotherapeutic management of single and multiple brain metastases was developed. METHODS: A systematic review and meta-analysis was performed. The Supportive Care Guidelines Group formulated clinical recommendations based on their interpretation of the evidence. External review of the report by Ontario practitioners was obtained through a mailed survey, and final approval was obtained from Cancer Care Ontario's Practice Guidelines Coordinating Committee (PGCC). RESULTS: One hundred and nine Ontario practitioners responded to the survey (return rate 44%). Ninety-six percent of respondents agreed with the interpretation of the evidence, and 92% agreed that the report should be approved. Minor revisions were made based on feedback from external reviewers and the PGCC. The PGCC approved the final practice guideline report. CONCLUSIONS: For adult patients with a clinical and radiographic diagnosis of brain metastases (single or multiple) we conclude that, ā€¢ Surgical excision should be considered for patients with good performance status, minimal or no evidence of extracranial disease, and a surgically accessible single brain metastasis. ā€¢ Postoperative whole brain radiotherapy (WBRT) should be considered to reduce the risk of tumour recurrence for patients who have undergone resection of a single brain metastasis. ā€¢ Radiosurgery boost with WBRT may improve survival in select patients with unresectable single brain metastases. ā€¢ The whole brain should be irradiated for multiple brain metastases. Standard dose-fractionation schedules are 3000 cGy in 10 fractions or 2000 cGy in 5 fractions. ā€¢ Radiosensitizers are not recommended outside research studies. ā€¢ In select patients, radiosurgery may be considered as boost therapy with WBRT to improve local tumour control. Radiosurgery boost may improve survival in select patients. ā€¢ Chemotherapy as primary therapy or chemotherapy with WBRT remains experimental. ā€¢ Supportive care is an option but there is a lack of Level 1 evidence as to which subsets of patients should be managed with supportive care alone. Qualifying statements addressing factors to consider when applying these recommendations are provided in the full report. The rigorous development, external review and approval process has resulted in a practice guideline that is strongly endorsed by Ontario practitioners

    HiTSEE KNIME: a visualization tool for hit selection and analysis in high-throughput screening experiments for the KNIME platform

    Get PDF
    We present HiTSEE (High-Throughput Screening Exploration Environment), a visualization tool for the analysis of large chemical screens used to examine biochemical processes. The tool supports the investigation of structure-activity relationships (SAR analysis) and, through a flexible interaction mechanism, the navigation of large chemical spaces. Our approach is based on the projection of one or a few molecules of interest and the expansion around their neighborhood and allows for the exploration of large chemical libraries without the need to create an all encompassing overview of the whole library. We describe the requirements we collected during our collaboration with biologists and chemists, the design rationale behind the tool, and two case studies on different datasets. The described integration (HiTSEE KNIME) into the KNIME platform allows additional flexibility in adopting our approach to a wide range of different biochemical problems and enables other research groups to use HiTSEE

    The role of steroids in the management of brain metastases: a systematic review and evidence-based clinical practice guideline

    Get PDF
    Do steroids improve neurologic symptoms in patients with metastatic brain tumors compared to no treatment? If steroids are given, what dose should be used? Comparisons include: (1) steroid therapy versus none. (2) comparison of different doses of steroid therapy. Target population These recommendations apply to adults diagnosed with brain metastases. Recommendations Steroid therapy versus no steroid therapy Asymptomatic brain metastases patients without mass effect Insufficient evidence exists to make a treatment recommendation for this clinical scenario. Brain metastases patients with mild symptoms related to mass effect Level 3 Corticosteroids are recommended to provide temporary symptomatic relief of symptoms related to increased intracranial pressure and edema secondary to brain metastases. It is recommended for patients who are symptomatic from metastatic disease to the brain that a starting dose of 4ā€“8Ā mg/day of dexamethasone be considered. Brain metastases patients with moderate to severe symptoms related to mass effect Level 3 Corticosteroids are recommended to provide temporary symptomatic relief of symptoms related to increased intracranial pressure and edema secondary to brain metastases. If patients exhibit severe symptoms consistent with increased intracranial pressure, it is recommended that higher doses such as 16Ā mg/day or more be considered. Choice of Steroid Level 3 If corticosteroids are given, dexamethasone is the best drug choice given the available evidence. Duration of Corticosteroid Administration Level 3 Corticosteroids, if given, should be tapered slowly over a 2Ā week time period, or longer in symptomatic patients, based upon an individualized treatment regimen and a full understanding of the long-term sequelae of corticosteroid therapy. Given the very limited number of studies (two) which met the eligibility criteria for the systematic review, these are the only recommendations that can be offered based on this methodology. Please see ā€œDiscussionā€ and ā€œSummaryā€ section for additional details

    Telerehabilitation versus traditional centre-based pulmonary rehabilitation for people with chronic respiratory disease: protocol for a randomised controlled trial

    Get PDF
    Background: Pulmonary rehabilitation is an effective therapeutic intervention for people with chronic respiratory disease. However, fewer than 5% of eligible individuals receive pulmonary rehabilitation on an annual basis, largely due to limited availability of services and difficulties associated with travel and transport. The Rehabilitation Exercise At Home (REAcH) study is an assessor-blinded, multi-centre, randomised controlled equivalence trial designed to compare the efficacy of home-based telerehabilitation and traditional centre-based pulmonary rehabilitation in people with chronic respiratory disease. Methods: Participants will undertake an 8-week group-based pulmonary rehabilitation program of twice-weekly supervised exercise training, either in-person at a centre-based pulmonary rehabilitation program or remotely from their home via the Internet. Supervised exercise training sessions will include 30 min of aerobic exercise (cycle and/ or walking training). Individualised education and self-management training will be delivered. All participants will be prescribed a home exercise program of walking and strengthening activities. Outcomes will be assessed by a blinded assessor at baseline, after completion of the intervention, and 12-months post intervention. The primary outcome is change in dyspnea score as measured by the Chronic Respiratory Questionnaire ā€“ dyspnea domain (CRQ-D). Secondary outcomes will evaluate the efficacy of telerehabilitation on 6- min walk distance, endurance cycle time during a constant work rate test, physical activity and quality of life. Adherence to pulmonary rehabilitation between the two models will be compared. A full economic analysis from a societal perspective will be undertaken to determine the cost-effectiveness of telerehabilitation compared to centre-based pulmonary rehabilitation. Discussion: Alternative models of pulmonary rehabilitation are required to improve both equity of access and patient-related outcomes. This trial will establish whether telerehabilitation can achieve equivalent improvement in outcomes compared to traditional centre-based pulmonary rehabilitation. If efficacious and cost-effective, the proposed telerehabilitation model is designed to be rapidly deployed into clinical practice.Narelle S. Cox, Christine F. McDonald, Jennifer A. Alison, Ajay Mahal, Richard Wootton, Catherine J. Hill, Janet Bondarenko, Heather Macdonald, Paul Oā€™Halloran, Paolo Zanaboni, Ken Clarke, Deidre Rennick, Kaye Borgelt, Angela T. Burge, Aroub Lahham, Bruna Wageck, Hayley Crute, Pawel Czupryn, Amanda Nichols and Anne E. Hollan
    • ā€¦
    corecore