895 resultados para literature survey
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We present a catalogue of galaxy photometric redshifts and k-corrections for the Sloan Digital Sky Survey Data Release 7 (SDSS-DR7), available on the World Wide Web. The photometric redshifts were estimated with an artificial neural network using five ugriz bands, concentration indices and Petrosian radii in the g and r bands. We have explored our redshift estimates with different training sets, thus concluding that the best choice for improving redshift accuracy comprises the main galaxy sample (MGS), the luminous red galaxies and the galaxies of active galactic nuclei covering the redshift range 0 < z < 0.3. For the MGS, the photometric redshift estimates agree with the spectroscopic values within rms = 0.0227. The distribution of photometric redshifts derived in the range 0 < z(phot) < 0.6 agrees well with the model predictions. k-corrections were derived by calibration of the k-correct_v4.2 code results for the MGS with the reference-frame (z = 0.1) (g - r) colours. We adopt a linear dependence of k-corrections on redshift and (g - r) colours that provide suitable distributions of luminosity and colours for galaxies up to redshift z(phot) = 0.6 comparable to the results in the literature. Thus, our k-correction estimate procedure is a powerful, low computational time algorithm capable of reproducing suitable results that can be used for testing galaxy properties at intermediate redshifts using the large SDSS data base.
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The aim of this thesis is to investigate the use of literature within the Swedish Upper Secondary EFL-classroom from the students’ perspective. How do the students in the study relate to literature and its use to enhance and enable their communicative competence and cultural understanding? Also, how do their answers compare with their teacher’s and the adult perspectives and findings from previous international research? The empirical data obtained from the study has been analysed from the perspectives of sociocultural and motivational theory, and the findings show that the participating students believe literature to be a good didactic tool to apply in the EFL-classroom, both in order to enhance their communicative competence and their cultural understanding. The students prefer to have a sociocultural approach to their literature-learning, with group-discussions of various sizes. The key for the students in this respect is interesting, relevant and engaging subject-matter, as well as a positive and motivational teacher. The responses given by the students correlate with those given by their teacher as well as previous international research. The students regard literature as a way of gaining new perspectives, as well as experiencing language in use. Where they diverge somewhat from the international research is in regard to literature’s use for enhancing their competence to speak in class, and that some students seem to think that communication and cultural understanding are separable. Future studies within this field might include the conducting of a larger and more in-depth survey regarding the students’ ideas about literature, culture and communication. Why do so many of the student respondents neither agree nor disagree with the statement concerning communication and cultural understanding being inseparable? This can be an important issue to investigate in today’s global climate of cross-cultural and intercultural experiences, especially in view of the political climate of diverse attitudes towards refugees, immigrants and emigration
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The importance of extensive literature reading in the English as a Foreign Language (EFL) context has been given increasing attention in recent research. Literature reading is also a required part of the national syllabi of the (EFL) courses offered to both adolescents and adults at Upper Secondary level in Sweden. This thesis aims to investigate the teachers’ process of making literature choices for extensive reading in upper secondary EFL courses in Sweden. Eight teachers of three different student groups took part in the study, representing adolescent university preparatory programs and vocational programs, as well as programs for adult students. Questionnaires were used and the data was analyzed for patterns revealing three main factors affecting teachers’ literature choice: language proficiency, reading experience and contextual factors. These three factors were fitted into the theoretical framework of psycholinguistic and sociolinguistic reading models, with the addition of a perspective of motivational research. The results of this survey underline the importance of extensive reading, according to teachers, and that motivation for literature choice can be primarily related to factors associated with psycholinguistic reading models. The survey also points to the need for further investigating of teachers’ own experiences of literature reading, searching for deeper motivational factors which influence teaching choices. Another future field of research is the choice of reading activities assigned together with the chosen literature, which probably also influence teachers’ choices in the Swedish EFL classroom.
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Previous research has shown multiple benefits and challenges with the incorporation of children’s literature in the English as a Second language (ESL) classroom. In addition, the use of children’s literature in the lower elementary English classroom is recommended by the Swedish National Agency for Education. Consequently, the current study explores how teachers in Swedish elementary school teach ESL through children’s literature. This empirical study involves English teachers from seven schools in a small municipality in Sweden. The data has been collected through an Internet survey. The study also connects the results to previous international research, comparing Swedish and international research. The results suggest that even though there are many benefits of using children’s literature in the ESL classroom, the respondents seldom use these authentic texts, due to limited time and a narrow supply of literature, among other factors. However, despite these challenges, all of the teachers claim to use children’s literature by reading aloud in the classroom. Based on the results, further research exploring pupils’ thoughts in contrast to teachers would be beneficial. In addition, the majority of the participants expressed that they wanted more information on how to use children’s literature. Therefore, additional research relating to beneficial methods of teaching English through children’s literature, especially in Sweden, is recommended.
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Data available on continuos-time diffusions are always sampled discretely in time. In most cases, the likelihood function of the observations is not directly computable. This survey covers a sample of the statistical methods that have been developed to solve this problem. We concentrate on some recent contributions to the literature based on three di§erent approaches to the problem: an improvement of the Euler-Maruyama discretization scheme, the use of Martingale Estimating Functions and the application of Generalized Method of Moments (GMM).
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Data available on continuous-time diffusions are always sampled discretely in time. In most cases, the likelihood function of the observations is not directly computable. This survey covers a sample of the statistical methods that have been developed to solve this problem. We concentrate on some recent contributions to the literature based on three di§erent approaches to the problem: an improvement of the Euler-Maruyama discretization scheme, the employment of Martingale Estimating Functions, and the application of Generalized Method of Moments (GMM).
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Uma parcela importante do crescimento econômico é devida a inovações. Esta dissertação revisa a literatura recente em propriedade intelectual. Esta revisão discute os seguintes artigos: Kremer (1998), Boldrin e Levine (2001), Kremer (2001), Shavell e Ypersele (2001), Lerner (2002) e DiMasi, Hansen e Grabowski (2003). Estes contém tanto artigos empíricos quanto teóricos. Na primeira categoria está um artigo sobre efeitos na inovação de mudanças na força das patentes e outro sobre custo de desenvolver novos medicamentos. Os estudos teóricos propõem melhorias e alternativas ao sistema de patentes, por exemplo, recompensas opcionais, compras de patentes, eliminação de patentes em alguns setores e compromisso de compra prévio.
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In this survey, we presented the general idea and main results from what we understand that are the most important contributions to contractual solutions to the holdup problem literature. The aim of this paper is to push the previous analysis, uniform the notation and provide a snapshot on the most recent literature, as well as bring topics for future inquires on this issue.
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This paper reports the results of a survey intended to discover the manner in which Soft Systems Methodology (SSM) is understood and used in Brazil. The focus is upon SSM papers published in national and international journals, and conferences, incorporating a refereeing procedure. To be included in the survey, publications had to meet at least one of the following criteria: (a) authorship is clearly of Brazilian nationality; or, (b) authorship is affiliated to a Brazilian institution; or (c) application is set in Brazil. Similar surveys reporting on the United Kingdom, Australia and, to a lesser extent, Spain have been published previously in the literature. This paper, therefore, contributes to the growing international understanding and usage of SSM. Ultimately the paper serves as an initial map of the developing context in Brazilian SSM theory and practice.
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Chlamydophila psittaci (C. psittaci) has been detected in 460 avian species, among them the most frequent are the Psittaciformes, Columbiformes, Anseriformes and raptors. In Brazil, the main avian species recognized as healthy carriers belong to the order Psittaciformes and Columbiformes, but very few studies have been done in other bird families. Reports of the occurrence of this disease in the clinical form are rare in the Ramphastids; consequently, they are not commonly evaluated for this agent. The present study reports the investigation of C. psittaci in 25 captive ramphastids from a zoological park in São Paulo State, Brazil. Swabs samples from the cloaca were submitted to semi-nested polymerase chain reaction (semi-nested PCR) for direct detection of the microorganism. Additionally, blood samples obtained from these birds were submitted to the Complement Fixation Test (CFT) for detection of antibodies anti-C. psittaci. The presence of C. psittaci was not detected in the cloacal swab samples tested by the PCR. Nevertheless, 16% (4/25) of the bird's sera were positive by the CFT. Among the species with positive results, there are the saffron toucanet (Pteroglossus bailloni) and black-necked-aracari (Pteroglossus aracari), two species with no descriptions of the survey of C. psittaci published in the literature. Intermittent elimination of C. psittaci is a feature of chronically infected birds; however the absence of a positive-antigen sample did not guarantee that the bird is Chlamydophila-free. The serological results obtained show that the ramphastids tested were previously exposed to the pathogen and developed immune response, but showed no clinical signs of the disease and didn't eliminate regularly the organism in their feces in the moment of the sample collection.
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This paper provides a general survey of the occurrence of diterpenes in the Asteraceae. Data on 4351 botanical occurrences were obtained from the literature. These were grouped by skeleton for each genus. Then, the genera were grouped by subtribes, which, in turn, were gathered in tribes, followed by subfamilies. In spite of the low number of species containing diterpenes, it was possible to describe some structural features of these compounds, i.e. The skeletal types in various taxa and the positions in some skeletons that are always oxidized or never undergo oxidation in some genera. Thus, it was verified that: in the subfamily Cichorioideae, only a few of the studied species possess diterpenes, wherein kaurane is the most frequent diterpene skeleton. In the Asteroideae, the presence of diterpenes is much greater than that in the Cichorioideae and Carduoideae. At tribal taxonomic level, for example, the Astereae produce labdanes and clerodanes; Heliantheae and Eupatorieae produce kauranes and labdanes, respectively; and Calenduleae produce pimaranes. Some taxonomic implications are presented. (c) 2005 the Linnean Society of London.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Engenharia de Produção - FEB
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Pós-graduação em Engenharia de Produção - FEB