305 research outputs found

    How teachers' practices and students' attitudes towards technology affect mathematics achievement: results and insights from PISA 2012

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    The present work seeks to deepen the impact of factors linked to the characteristics of teaching practices and students' attitudes towards the use of technology on their performance in mathematics in the process of teaching-learning in the Spanish context. In this sense, this study is a secondary analysis of the PISA 2012 data. Therefore, it is an ex post facto design. Regarding the attitudes and the contextual variables, the results do coincide with the accumulated evidence. However, once these contextual effects have been controlled for, the negative relationship found between the pedagogic strategies used by the teachers and the mathematics score cannot but convey perplexity, since the results relative to student-oriented, formative assessment and teacher-directed instruction are clearly contradictory to the solid previous evidence. The data do not allow us to explain this paradoxical result. We dare to point to a conjecture that we find plausible. All these complex variables are informed through questionnaires responded to by students and require a great degree of inference in the answers. Future studies must consider the complexity of the measured variables as well as the students' perception and understanding of them

    Lactic Acid Yield Using Different Bacterial Strains, Its Purification, and Polymerization through Ring-Opening Reactions

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    Laboratory-scale anaerobic fermentation was performed to obtain lactic acid from lactose, using five lactic acid bacteria: Lactococcus lactis, Lactobacillus bulgaricus, L. delbrueckii, L. plantarum, and L. delbrueckii lactis. A yield of 0.99 g lactic acid/g lactose was obtained with L. delbrueckii, from which a final concentration of 80.95 g/L aqueous solution was obtained through microfiltration, nanofiltration, and inverse osmosis membranes. The lactic acid was polymerized by means of ring-opening reactions (ROP) to obtain poly-DL-lactic acid (PDLLA), with a viscosity average molecular weight (Mv) of 19,264 g/mol

    Institutional and behaviour-change interventions to support COVID-19 public health measures: a review by the Lancet Commission Task Force on public health measures to suppress the pandemic

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    The Lancet COVID-19 Commission Task Force for Public Health Measures to Suppress the Pandemic was launched to identify critical points for consideration by governments on public health interventions to control coronavirus disease 2019 (COVID-19). Drawing on our review of published studies of data analytics and modelling, evidence synthesis and contextualisation, and behavioural science evidence and theory on public health interventions from a range of sources, we outline evidence for a range of institutional measures and behaviour-change measures. We cite examples of measures adopted by a range of countries, but especially jurisdictions that have, thus far, achieved low numbers of COVID-19 deaths and limited community transmission of severe acute respiratory syndrome coronavirus 2. Finally, we highlight gaps in knowledge where research should be undertaken. As countries consider long-term measures, there is an opportunity to learn, improve the response and prepare for future pandemics

    Crime, Institutions and Sector-Specific FDI in Latin America

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    In this article, we explore how crime and institutions affect the flow of capital in the form of foreign direct investment (FDI) to Latin American and Caribbean countries in the primary, secondary and tertiary sectors during the 1996-2010 period. We use three different variables related to violent crime: homicides, crime victimization, and an index of organized crime. We find that there is a correlation between the institutional and crime variables, where the significance of institutional variables tends to disappear when the crime variables are added to the model. We find that higher crime victimization and organized crime are associated with lower FDI in the tertiary sector. We do not find that crime affects FDI inflows to Latin America in the primary and secondary sector

    A GHEP-ISFG collaborative study on the genetic variation of 38 autosomal indels for human identification in different continental populations

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    A collaborative effort was carried out by the Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) to promote knowledge exchange between associate laboratories interested in the implementation of indel-based methodologies and build allele frequency databases of 38 indels for forensic applications. These databases include populations from different countries that are relevant for identification and kinship investigations undertaken by the participating laboratories. Before compiling population data, participants were asked to type the 38 indels in blind samples from annual GHEP-ISFG proficiency tests, using an amplification protocol previously described. Only laboratories that reported correct results contributed with population data to this study. A total of 5839 samples were genotyped from 45 different populations from Africa, America, East Asia, Europe and Middle East. Population differentiation analysis showed significant differences between most populations studied from Africa and America, as well as between two Asian populations from China and East Timor. Low FST values were detected among most European populations. Overall diversities and parameters of forensic efficiency were high in populations from all continents.RP is supported by a postdoctoral fellowship (SFRH/BPD/81986/2011) awarded by the Portuguese Foundation for Science and Technology (FCT) and co-financed by the European Social Fund (Human Potential Thematic Operational Programme – POPH

    GHEP-ISFG collaborative exercise on mixture profiles of autosomal STRs (GHEP-MIX01, GHEP-MIX02 and GHEP-MIX03): results and evaluation

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    One of the main objectives of the Spanish and Portuguese-Speaking Group of the International Society for Forensic Genetics (GHEP-ISFG) is to promote and contribute to the development and dissemination of scientific knowledge in the area of forensic genetics. Due to this fact, GHEP-ISFG holds different working commissions that are set up to develop activities in scientific aspects of general interest. One of them, the Mixture Commission of GHEP-ISFG, has organized annually, since 2009, a collaborative exercise on analysis and interpretation of autosomal short tandem repeat (STR) mixture profiles. Until now, three exercises have been organized (GHEP-MIX01, GHEP-MIX02 and GHEP-MIX03), with 32, 24 and 17 participant laboratories respectively. The exercise aims to give a general vision by addressing, through the proposal of mock cases, aspects related to the edition of mixture profiles and the statistical treatment. The main conclusions obtained from these exercises may be summarized as follows. Firstly, the data show an increased tendency of the laboratories toward validation of DNA mixture profiles analysis following international recommendations (ISO/IEC 17025:2005). Secondly, the majority of discrepancies are mainly encountered in stutters positions (53.4%, 96.0% and 74.9%, respectively for the three editions). On the other hand, the results submitted reveal the importance of performing duplicate analysis by using different kits in order to reduce errors as much as possible. Regarding the statistical aspect (GHEP-MIX02 and 03), all participants employed the likelihood ratio (LR) parameter to evaluate the statistical compatibility and the formulas employed were quite similar. When the hypotheses to evaluate the LR value were locked by the coordinators (GHEP-MIX02) the results revealed a minor number of discrepancies that were mainly due to clerical reasons. However, the GHEP-MIX03 exercise allowed the participants to freely come up with their own hypotheses to calculate the LR value. In this situation the laboratories reported several options to explain the mock cases proposed and therefore significant differences between the final LR values were obtained. Complete information concerning the background of the criminal case is a critical aspect in order to select the adequate hypotheses to calculate the LR value. Although this should be a task for the judicial court to decide, it is important for the expert to account for the different possibilities and scenarios, and also offer this expertise to the judge. In addition, continuing education in the analysis and interpretation of mixture DNA profiles may also be a priority for the vast majority of forensic laboratories.Fil: Sala, Adriana Andrea. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Servicio de Huellas Digitales Genéticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Crespillo, M.. Instituto Nacional de Toxicología y Ciencias Forenses; EspañaFil: Barrio, P. A.. Instituto Nacional de Toxicología y Ciencias Forenses; EspañaFil: Luque, J. A.. Instituto Nacional de Toxicología y Ciencias Forenses; EspañaFil: Alves, Cíntia. Universidad de Porto; PortugalFil: Aler, M.. Servicio de Laboratorio. Sección de Genética Forense y Criminalística; EspañaFil: Alessandrini, F.. Università Politecnica delle Marche. Department of Biomedical Sciences and Public Health; ItaliaFil: Andrade, L.. Instituto Nacional de Medicina Legal e Ciências Forenses, Delegação do Centro. Serviço de Genética e Biologia Forenses; PortugalFil: Barretto, R. M.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Bofarull, A.. Instituto Nacional de Toxicología y Ciencias Forenses; EspañaFil: Costa, S.. Instituto Nacional de Medicina Legal y Ciencias Forenses; PortugalFil: García, M. A.. Servicio de Criminalística de la Guardia Civil. Laboratorio Central de Criminalística. Departamento de Biología; EspañaFil: García, O.. Basque Country Police. Forensic Genetics Section. Forensic Science Unit; EspañaFil: Gaviria, A.. Cruz Roja Ecuatoriana. Laboratorio de Genética Molecular; EcuadorFil: Gladys, A.. Corte Suprema de Justicia de la Nación; ArgentinaFil: Gorostiza, A.. Grupo Zeltia. Genomica S. A. U.. Laboratorio de Identificación Genética; EspañaFil: Hernández, A.. Instituto Nacional de Toxicología y Ciencias Forenses; EspañaFil: Herrera, M.. Laboratorio Genda S. A.; ArgentinaFil: Hombreiro, L.. Jefatura Superior de Policía de Galicia. Brigada de Policía Científica. Laboratorio Territorial de Biología – ADN; EspañaFil: Ibarra, A. A.. Universidad de Antioquia; ColombiaFil: Jiménez, M. J.. Policia de la Generalitat – Mossos d’Esquadra. Divisió de Policia Científica. Àrea Central de Criminalística. Unitat Central de Laboratori Biològic; EspañaFil: Luque, G. M.. Instituto Nacional de Toxicología y Ciencias Forenses; EspañaFil: Madero, P.. Centro de Análisis Genéticos; EspañaFil: Martínez Jarreta, B.. Universidad de Zaragoza; EspañaFil: Masciovecchio, M. Verónica. IACA Laboratorios; ArgentinaFil: Modesti, Nidia Maria. Provincia de Córdoba. Poder Judicial; ArgentinaFil: Moreno, F.. Servicio Médico Legal. Unidad de Genética Forense; ChileFil: Pagano, S.. Dirección Nacional de Policía Técnica. Laboratorio de Análisis de ADN para el CODIS; UruguayFil: Pedrosa, S.. Navarra de Servicios y Tecnologías S. A. U.; EspañaFil: Plaza, G.. Neodiagnostica S. L.; EspañaFil: Prat, E.. Comisaría General de Policía Científica. Laboratorio de ADN; EspañaFil: Puente, J.. Laboratorio de Genética Clínica S. L.; EspañaFil: Rendo, F.. Universidad del País Vasco; EspañaFil: Ribeiro, T.. Instituto Nacional de Medicina Legal e Ciências Forenses, Delegação Sul. Serviço de Genética e Biologia Forenses; PortugalFil: Santamaría, E.. Instituto Nacional de Toxicología y Ciencias Forenses; EspañaFil: Saragoni, V. G.. Servicio Médico Legal. Departamento de Laboratorios. Unidad de Genética Forense; ChileFil: Whittle, M. R.. Genomic Engenharia Molecular; Brasi
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