1,720,989 research outputs found
A PDF micromixing model of dispersion for atmospheric flow. Part II: application to convective boundary layer
Full text linkThe Lagrangian stochastic probability density function (PDF) model developed by Cassiani et al. [Atmos. Environ. (2005) Part 1] is extended to the atmospheric convective boundary layer. The model is applied to simulate concentration statistics and PDF generated by passive releases from point and line sources in the convective boundary layer. A dynamical time-expandable grid is implemented, which optimises the computational resources required for dispersion simulations in atmospheric flow. A parameterised formulation for the micromixing time scale in convective conditions is derived. Model concentration statistics including mean field, fluctuations and concentration PDF are tested with four water tank experiments
A PDF micromixing model of dispersion for atmospheric flow. Part I: development of the model, application to homogeneous turbulence and to neutral boundary layer
No full textA Lagrangian stochastic (LS) probability density function (PDF) model has been developed to study statistics and PDF of concentration generated by continuous releases of passive substances from point and line sources in atmospheric flow. The model simulates the combined effect of turbulent mixing (macromixing) and molecular diffusivity (micromixing) on dispersion of tracers. Turbulent dispersion is modelled using an LS model; molecular diffusivity is simulated by an interaction by exchange with the conditional mean (IECM) model. A dynamical computational grid, which expands with time around the plume, has been developed to optimise computational time and memory requirements. The model has been tested with the results of a two-particle LS model in homogeneous turbulence and with wind tunnel observations in a neutral boundary layer. The proposed model can account for chemical reactions in a direct way with no closure assumptions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
High-grade gliomas: results in patients treated with adjuvant radiotherapy alone and with adjuvant radio-chemotherapy
No full textBACKGROUND: Despite advances in the surgical, radiotherapeutic and chemotherapeutic fields, the outcome for patients with high-grade gliomas remains poor. Our experience of patients treated with and without chemotherapy is reported. MATERIALS AND METHODS: From April 1999 to July 2003, 30 patients with high-grade gliomas were treated: 13 received adjuvant radiotherapy (RT) alone whereas 17 received temozolomide 75 mg/m2/d during the irradiation time and 200 mg/m2 daily per 5 consecutive days, every 28 days for three to six cycles, starting 4 weeks after the end of radiotherapy. RESULTS: The median follow-up was 12.5 months. The median overall survival (OS) was 15 months. In patients treated with RT plus chemotherapy, no statistical difference was observed between those who had undergone partial surgical resection and those with total resection (p=0.5128). In patients with glioblastoma multiforme (GBM) treated with combined radiochemotherapy, the median OS was 18 months, while it was 7 months (p=0.0204) in those treated without chemotherapy. Multivariate analysis (Cox model) evidenced statistical differences for performance status (p =0.002) and for the type of adjuvant therapy (p=0.006). CONCLUSION: Radio-chemotherapy plus adjuvant temozolomide seemed to offer the best results in patients not submitted to debulking surgery. The performance status remained the most important prognostic factor. Tolerance to the combined regimen was very good
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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