1,720,976 research outputs found
Variation in survival of children with central nervous system (CNS) malignancies diagnosed in Europe between 1978 and 1992: the EUROCARE study.
No full textEUROCARE is a population-based survival study including data from European Cancer Registries. The present paper analyses survival after a malignant neoplasm of the central nervous system (CNS) in childhood (aged 0--14 years at diagnosis). The database includes 6130 cases from 34 population-based registries in 17 countries: 1558 were primitive neuroectodermal tumours (PNET) and 4087 astrocytoma, ependymoma or other gliomas: these morphologies were grouped in the analyses in order to reduce the diagnostic variability among the registries. 87% of cases were microscopically diagnosed (range among registries 71--100%) and losses to follow-up were limited to 2% (range 0--14%). Actuarial analyses indicate that the European (weighted) average of 5 years cumulative survival for cases diagnosed in 1978--1989 was 53% (95% confidence interval (CI) 49--57) for CNS neoplasms, 44% (95% CI 37--50) for PNET and 60% (95% CI 55--65) for the glioma-related types. Analysis of the sub-set of cases diagnosed in 1985--1989 revealed better results: cumulative survival at 5 years was 61% (95% CI: 55--65) for all CNS neoplasms; 48% (95% CI 41--56) for PNET and 68% (95% CI 62--73) for glioma-related types. Compared with older children, infants showed poorer prognosis: in 1978--1989 the 5-year survival rate was 33% (95% CI 23--45) and in 1985--1989 it was 46% (95% CI 34--59). Variability among countries was very large, with 5-year survival for CNS tumours diagnosed in 1985--1989 ranging from 28% in Estonia (95% CI 17--43) to 73% Sweden (95% CI 59--83) and 75% in Iceland (95% CI 35--95) and 73% in Finland (95% CI 66--79). Time trends were studied in a multivariate analysis observing a reduction in the risk of death in periods of diagnosis 1982--1985 (hazard ratio (HR)=0.85; 95% CI 0.78--0.93) and 1986--1989 (HR=0.70; 95% CI 0.64--0.77) compared with 1978--1981. The analysis were extended to 1990--1992 for the countries whose registries provided data for that period did not indicate any further progress. Results of this study confirm the large variability in European countries and indicate a positive trend in the survival probability for cases diagnosed in the 1980s
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
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Raffronto di Vari Metodi per l’Identificazione dell’Espressione Genica Differenziale, un’Applicazione con Oligonucleotidi alla Soppressione del Gene Antiapoptosi Survivina
No full textA very common problem that is adressed using microarray technology is that of identificating genes that are differentially expressed between two or more classes of samples. For this purpose many methods have been proposed and made available to a wide range of users by supplying related software. Refinements of familiar tools such as the t-test are used to take the multiplicity problem into account (Dudoit et al. 2002), and to obtain a reliable estimate of the variance of gene expression (Tusher et al. 2001), as well as model based methods, both in a frequentist (Kerr and Churchill 2001) and Bayesian framework (Gottardo et al. 2002). These methods imply different hypotheses and their use on data can lead to substantially different results. The purpose of this work is to evaluate and compare, through a case study, results from different methods for identifying differentially expressed genes
Life expectancy as an indicator of outcome in follow-up of population-based cancer registries: the example of childhood leukemia.
No full textBACKGROUND: Survival analysis is a standard methodology to assess progress in oncology disease treatment. However, survival analysis commonly only measures survival during the treatment period (and the period immediately afterwards), and does not provide an estimate of life expectancy, which is often of more interest to patients and to health policy makers. In this paper we propose a method to estimate childhood acute lymphoblastic leukemia (ALL) life expectancy through the integration of traditional survival analysis and life expectancy tables. PATIENTS AND METHODS: The study included 305 incident cases registered by the Childhood Cancer Registry of Piedmont in 1979-1991. Vital status on 30 June 2004 was known for 304 cases. Survival analyses were carried out using the Kaplan-Meier method and the Gompertz model, according to the time period of diagnosis and gender. RESULTS: Cumulative survival at 5 years increased from 58.6% (95% CI 48.9-68.3) for cases diagnosed in March 1979-July 1982 to 79.1% (95% CI 70.8-87.5) in March 1987-February 1991 (P = 0.002). Average life expectancy increased from 46.1 years for boys and 42.6 years for girls diagnosed in March 1979-July 1982 to 58.3 and 69.1, respectively, in March 1987-February 1991. CONCLUSIONS: These analyses show an improvement over the time period of diagnosis of life expectancy for children with ALL
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
