Browsing by Author "Salinas, M"

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    Beyond Nintendo: design and assessment of educational video games for first and second grade students
    (PERGAMON-ELSEVIER SCIENCE LTD, 2003) Rosas, R; Nussbaum, M; Cumsille, P; Marianov, V; Correa, M; Flores, P; Grau, V; Lagos, F; Lopez, X; Lopez, V; Rodriguez, P; Salinas, M
    The main objective of this study was to evaluate the effects of the introduction of educational videogames into the classroom, on, learning, motivation, and classroom dynamics. These effects were studied using a sample of 1274 students from economically disadvantaged schools in Chile. The videogames were specifically designed to address the educational goals of the first and second years of school, for basic mathematics and reading comprehension. The sample was divided into experimental groups (EG), internal control groups (IC) and external control groups (EC). Students in the EG groups, used the experimental video games during an average of 30 h over a 3-month period. They were evaluated on their acquisition of reading comprehension, spelling, and mathematical skills, and on their motivation to use video games. Teachers' expectations of change due to the use of video games, their technological transfer, and handling of classroom dynamics, were assessed through ad hoc tests and classroom observations. The results show significant differences between the EG and IC groups in relation to the EC group in Math, Reading Comprehension and Spelling, but no significant differences in these aspects were found between the EG and the IC groups. Teacher reports and classroom observations confirm an improvement in motivation to learn, and a positive technological transfer of the experimental tool. Although further studies regarding the effects of learning through videogame use are imperative, positive effects on motivation and classroom dynamics, indicate that the introduction of educational video games can be a useful tool in promoting learning within the classroom. (C) 2002 Elsevier Science Ltd. All rights reserved.
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    Evaluating environmental investments: A real options approach
    (INST OPERATIONS RESEARCH MANAGEMENT SCIENCES, 1998) Cortazar, G; Schwartz, ES; Salinas, M
    The paper presents a model that determines when (at which output price level) it is optimum for a firm to invest in environmental technologies and which are the main parameters that affect this decision. Our analysis shows that firms require high output price levels to be induced to invest in environmental technologies, because they optimally would not want to commit to a heavy irreversible investment that could turn out to be unprofitable in the event of a price fall. A comparative static analysis predicts that firms in industries with high output price volatility would be more reluctant to invest in environmental protection technologies and would be more willing to operate at low output levels (thus attaining low emission levels). Increases in the interest rate would also reduce optimal environmental investment levels.
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    Incidence of BRCA1 and BRCA2 mutations in 54 Chilean families with breast/ovarian cancer, genotype-phenotype correlations
    (2006) Gallardo, M; Silva, A; Rubio, L; Alvarez, C; Torrealba, C; Salinas, M; Tapia, T; Faundez, P; Palma, L; Riccio, M; Paredes, H; Rodriguez, M; Cruz, A; Rousseau, C; King, M; Camus, M; Alvarez, M; Carvallo, P
    Our aim was to analyze the incidence of mutations in BRCA1 and BRCA2 genes in 54 families with breast/ovarian cancer. Families were selected from three Institutions following the standard criteria for hereditary breast/ovarian cancer. PCR amplification of all exons was performed, followed by SSCP, heteroduplex, PTT and sequencing analysis. We identified eight truncation mutations, three in the BRCA1 gene and five in the BRCA2 gene. Three of these mutations have not been reported previously by other groups: 308insA in one family, 3936 C > T in two families, for BRCA1, and 4970insTG in one family for BRCA2. In addition two families having Ashkenazi Jewish ancestors present the well known mutations 185delAG and 6174delT. Interestingly, 5 out of 11 families have mutations recurrent in Spanish families. Among the 54 families selected, seven have breast and ovary cancer cases, and only two presented a mutation in BRCA1 or BRCA2 genes. Other cancers as prostate and stomach are frequent among relatives carrying the mutation. Five cases of very early onset (< 31 years old) breast cancer were detected. The frequencies of BRCA1 (0.074) and BRCA2 (0.13) mutations in our families is low but similar to the incidence found in other populations, like in Spain. Since is widely known that risk factors that modulate the development of breast cancer such as lifestyle risk factors, geographic location, country of origin and socioeconomic status, besides a familial history of breast cancer our findings suggest that the history of colonization and immigrations is very relevant when studying hereditary factors associated to breast cancer.