278 research outputs found

    Decomposition of Differences

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    This paper examines methods of decomposing a difference in levels between groups for a dependent variable such as income. Applied to regression equations, this technique estimates the contribution to the difference from divergent characteristics and divergent rates of converting characteristics into the dependent variable. The consequences of an "interaction" component being present in the decomposition is examined. The paper, using data from the 1960 Census, shows how ignoring the interaction term can influence results.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68707/2/10.1177_004912417500300306.pd

    Una comunidad de construcción de conocimiento: el caso de la maestría en ingeniería de la UADY

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    Se desea estudiar la construcción de conocimiento en una comunidad epistémica, entendida como una comunidad de práctica (CoP) por medio del uso de conocimiento matemático. Se analiza el uso de las gráficas de variación y cambio en tesis, revistas de investigación y notas de clases de la Maestría en ingeniería de la Universidad Autónoma de Yucatán (UADY) en tres diferentes escenarios de interacción, a los cuales denominamos episodios: clases de la maestría, productos de investigación y con el asesor; en todos los escenarios las personas son expertos (profesores investigadores) y aprendices (alumnos en diferentes etapas) de la especialidad de ingeniería ambiental, construcción y estructuras. Se presentarán algunos avances referentes al método y cómo se inicia el análisis de la información para evidenciar la construcción de conocimiento, todo ello de acorde con la problemática

    The PHENIX Experiment at RHIC

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    The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix

    Guidelines for chemotherapy of biliary tract and ampullary carcinomas

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    Few randomized controlled trials (RCTs) with large numbers of patients have been conducted to date in patients with biliary tract cancer, and standard chemotherapy has not been established yet. In this article we review previous studies and clinical trials regarding chemotherapy for unresectable biliary tract cancer, and we present guidelines for the appropriate use of chemotherapy in patients with biliary tract cancer. According to an RCT comparing chemotherapy and best supportive care for these patients, survival was significantly longer and quality of life was significantly better in the chemotherapy group than in the control group. Thus, chemotherapy for patients with biliary tract cancer seems to be a significant treatment of choice. However, chemotherapy for patients with biliary tract cancer should be indicated for those with unresectable, locally advanced disease or distant metastasis, or for those with recurrence after resection. That is why making the diagnosis of unresectable disease should be done with greatest care. As a rule, pathological diagnosis, including cytology or histopathological diagnosis, is preferable. Chemotherapy is recommended in patients with a good general condition, because in patients with general deterioration, such as those with a performance status of 2 or 3 or those with insufficient biliary decompression, the benefit of chemotherapy is limited. As chemotherapy for unresectable biliary tract cancer, the use of gemcitabine or tegafur/gimeracil/oteracil potassium is recommended. As postoperative adjuvant chemotherapy, no effective adjuvant therapy has been established at the present time. It is recommended that further clinical trials, especially large multi-institutional RCTs (phase III studies) using novel agents such as gemcitabine should be performed as soon as possible in order to establish a standard treatment
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