14 research outputs found

    A Reverse Shock in GRB 181201A

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    We present comprehensive multiwavelength radio to X-ray observations of GRB 181201A spanning from ≈150 s to ≈163 days after the burst, comprising the first joint ALMA-VLA-GMRT observations of a gamma-ray burst (GRB) afterglow. The radio and millimeter-band data reveal a distinct signature at ≈3.9 days, which we interpret as reverse-shock (RS) emission. Our observations present the first time that a single radio-frequency spectral energy distribution can be decomposed directly into RS and forward shock (FS) components. We perform detailed modeling of the full multiwavelength data set, using Markov Chain Monte Carlo sampling to construct the joint posterior density function of the underlying physical parameters describing the RS and FS synchrotron emission. We uncover and account for all discovered degeneracies in the model parameters. The joint RS-FS modeling reveals a weakly magnetized (σ ≈ 3 × 10-3), mildly relativistic RS, from which we derive an initial bulk Lorentz factor of Γ0 ≈ 103 for the GRB jet. Our results support the hypothesis that low-density environments are conducive to the observability of RS emission. We compare our observations to other events with strong RS detections and find a likely observational bias selecting for longer lasting, nonrelativistic RSs. We present and begin to address new challenges in modeling posed by the present generation of comprehensive, multifrequency data sets

    La psicología educacional y el sistema de educación en Cuba

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    Tumor carcinoide bronquial. Análisis retrospectivo de 62 casos tratados quirúrgicamente

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    Objetivo: Evaluar los resultados del tratamiento quirúrgico del tumor carcinoide pulmonar. Pacientes y método: Se han revisado las historias clínicas de 62 pacientes intervenidos quirúrgicamente por un tumor carcinoide pulmonar entre mayo de 1985 y octubre de 2000. Resultados: Cincuenta y dos pacientes tenían un carcinoide típico y 10 un carcinoide atípico. Nueve pacientes presentaban metástasis ganglionares hiliares o mediastínicas y 5 presentaban metástasis a distancia. Estas últimas fueron más frecuentes en el subtipo histológico carcinoide atípico con diferencias estadísticamente significativas. Cinco pacientes tenían clínica de síndrome carcinoide. La supervivencia global a los 15 años fue del 70% y la supervivencia media de 138 ± 11 meses. No encontramos asociación estadística entre el hábito tabáquico y el desarrollo de tumor carcinoide. Conclusiones: Aunque el tumor carcinoide se comporta como un tumor de bajo grado de malignidad, su tratamiento debe realizarse de modo similar al del resto de los tumores malignos pulmonares; la resección quirúrgica con intención curativa es la técnica de elección siempre que sea posible

    BioGlue and Peri-strips in lung volume reduction surgery : pilot randomised controlled trial

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    Background Both tissue sealants and buttressing have been advocated to reduce alveolar air leaks from staple lines following Lung Volume Reduction Surgery (LVRS). However, the long term detrimental effects of buttressing material are increasingly apparent. We performed a pilot prospective randomised self controlled trial in patients undergoing LVRS comparing BioGlue and Peri-strips as adjuncts in preventing alveolar air-leaks. Methods A pilot prospective self controlled clinical trial was conducted in patients undergoing LVRS. Each patient was treated with BioGlue on one side and pericardial buttress on the other side as an adjunct to the staple line. The sides were randomised for adjuncts with each patient acting as his own control. Duration of air leak, intercostal drainage and time to chest drain removal were the study end points. Results 10 patients undergoing the procedure were recruited between December 2005 and October 2007. There were 6 men and the mean age was 59.8 ± 4.9 years. There was one mortality due to multi-organ failure. The BioGlue treated side had a shorter mean duration of air-leak (3.0 ± 4.6 versus 6.5 ± 6.9 days), lesser chest drainage volume (733 ± 404 ml versus 1001 ± 861) and shorter time to chest drain removal (9.7 ± 10.6 versus 11.5 ± 11.1 days) compared with Peri-strips. Conclusion This study demonstrates comparable efficacy of BioGlue and Peri-strips, however there is a trend favouring the BioGlue treated side in terms of reduction in air-leak, chest drainage volumes, duration of chest drainage and significant absence of complications. A larger sample size is needed to validate this result

    The IASLC Lung Cancer Staging Project: External Validation of the Revision of the TNM Stage Groupings in the Eighth Edition of the TNM Classification of Lung Cancer

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    Introduction Revisions to the TNM stage classifications for lung cancer, informed by the international database (N = 94,708) of the International Association for the Study of Lung Cancer (IASLC) Staging and Prognostic Factors Committee, need external validation. The objective was to externally validate the revisions by using the National Cancer Data Base (NCDB) of the American College of Surgeons. Methods Cases presenting from 2000 through 2012 were drawn from the NCDB and reclassified according to the eighth edition stage classification. Clinically and pathologically staged subsets of NSCLC were analyzed separately. The T, N, and overall TNM classifications were evaluated according to clinical, pathologic, and â\u80\u9cbestâ\u80\u9d stage (N = 780,294). Multivariate analyses were carried out to adjust for various confounding factors. A combined analysis of the NSCLC cases from both databases was performed to explore differences in overall survival prognosis between the two databases. Results The databases differed in terms of key factors related to data source. Survival was greater in the IASLC database for all stage categories. However, the eighth edition TNM stage classification system demonstrated consistent ability to discriminate TNM categories and stage groups for clinical and pathologic stage. Conclusions The IASLC revisions made for the eighth edition of lung cancer staging are validated by this analysis of the NCDB database by the ordering, statistical differences, and homogeneity within stage groups and by the consistency within analyses of specific cohorts
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