334 research outputs found
Learning Mathematics Problem Solving through Test Practice: a Randomized Field Experiment on a Global Scale
We measure the effect of a single test practice on 15-year-old studentsâ ability to solve mathematics problems using large, representative samples of the schooled population in 32 countries. We exploit three unique features of the 2012 administration of the Programme for International Student Assessment (PISA), a large-scale, low-stakes international assessment. During the 2012 PISA administration, participating students were asked to sit two separate tests consisting of problem-solving tasks. Both tests included questions that covered the same internationally recognized and validated framework for mathematics assessment. Students were randomly assigned in the first, 2-h-long test to one of three test versions containing varying amounts of mathematics, reading, and science problems. We found that the amount of mathematics problems in the first test had a small positive effect on mean mathematics performance on the second test, but no effect on general reasoning and problem-solving ability. Subject-specific effects of test practice on subsequent test performance were found over both short lags (same day) and medium lags (1â7 days). The learning gains ascribed to mathematics problem-solving practice were larger for boys than for girls
What School Factors are Associated with the Success of Socio-Economically Disadvantaged Students? An Empirical Investigation Using PISA Data
Many school-level policies, such as school funding formulae and teacher allocation mechanisms, aim at reducing the influence of studentsâ low socio-economic condition on academic achievement. Benchmarks and indicators based on large-scale international assessments can be used to measure academic success and identify if and when disadvantaged students are successful. We build on such work and develop a new method for identifying a cross-country comparable metric of the academic success of socio-economically disadvantaged students using data from the Programme for International Student Assessment (PISA). We estimate the prevalence of successful disadvantaged students in 56 countries, as well as changes over time between 2006 and 2015. In addition, we focus on the PISA 2015 edition and explore school factors associated with the probability that disadvantaged students will be successful academically in a subsample of 18 countries. Findings reveal that successful disadvantaged students attend schools with a better disciplinary climate and that provide additional time for instruction in key subjects
Pathogenetic, Clinical, and Prognostic Features of Adult t(4;11)(q21;q23)/MLL-AF4 Positive B-Cell Acute Lymphoblastic Leukemia
Translocation t(4;11)(q21;q23) leading to formation of MLL-AF4 fusion gene is found in about 10% of newly diagnosed B-cell acute lymphoblastic leukemia (ALL) in adult patients. Patients expressing this chromosomal aberration present typical biological, immunophenotypic, and clinical features. This form of leukemia is universally recognized as high-risk leukemia and treatment intensification with allogeneic hematopoietic stem cell transplantation (HSCT) in first complete remission (CR) could be a valid option to improve prognosis, but data obtained from the literature are controversial. In this review, we briefly describe pathogenetic, clinical, and prognostic characteristics of adult t(4;11)(q21;q23)/MLL-AF4 positive ALL and provide a review of the clinical outcome reported by the most important cooperative groups worldwide
What School Factors are Associated with the Success of Socio-Economically Disadvantaged Students? An Empirical Investigation Using PISA Data
Many school-level policies, such as school funding formulae and teacher allocation mechanisms, aim at reducing the influence of studentsâ low socio-economic condition on academic achievement. Benchmarks and indicators based on large-scale international assessments can be used to measure academic success and identify if and when disadvantaged students are successful. We build on such work and develop a new method for identifying a cross-country comparable metric of the academic success of socio-economically disadvantaged students using data from the Programme for International Student Assessment (PISA). We estimate the prevalence of successful disadvantaged students in 56 countries, as well as changes over time between 2006 and 2015. In addition, we focus on the PISA 2015 edition and explore school factors associated with the probability that disadvantaged students will be successful academically in a subsample of 18 countries. Findings reveal that successful disadvantaged students attend schools with a better disciplinary climate and that provide additional time for instruction in key subjects
Self-assembly of "Mickey Mouse" shaped colloids into tube-like structures: experiments and simulations
Self-assembly of "Mickey Mouse" shaped colloids into tube-like structures: experiments and simulations
Biological and Soft Matter Physic
Zoledronic acid induces a significant decrease of circulating endothelial cells and circulating endothelial precursor cells in the early prostate cancer neoadjuvant setting
Purpose: Published data demonstrated that zoledronic acid (ZOL) exhibits antiangiogenetic effects. A promising tool for monitoring antiangiogenic therapies is the measurement of circulating endothelial cells (CECs) and circulating endothelial precursor cells (CEPs) in the peripheral blood of patients. Our aim was to investigate the effects of ZOL on levels of CECs and CEPs in localized prostate cancer. Methods: Ten consecutive patients with a histologic diagnosis of low-risk prostate adenocarcinoma were enrolled and received an intravenous infusion of ZOL at baseline (T0), 28 days (T28) and 56 days (T56). Blood samples were collected at the following times: T0 (before the first infusion of ZOL), T3 (72 h after the first dose), T28, T56 (both just before the ZOL infusion) and T84 (28 days after the last infusion of ZOL) and CEC/CEP levels were directly quantified by flow cytometry at all these time points. Results: Our analyses highlighted a significant reduction of mean percentage of CECs and CEPs after initiation of ZOL treatment [p = 0.014 (at day 3) and p = 0.012 (at day 84), respectively]. Conclusion: These preliminary results demonstrate that ZOL could exert an antiangiogenic effect in early prostate cancer through CEP and CEC modulation
A fast synthesis route of boron-carbon-nitrogen ultrathin layers towards highly mixed ternary B-C-N phases
We report a direct and fast synthesis route to grow boron-carbon-nitrogen layers based on microwave-assisted plasma enhanced chemical vapour deposition (PECVD) by using methylamine borane as a single source molecular precursor. This easy and inexpensive method allows controlled and reproducible growth of B-C-N layers onto thin Cu foils. Their morphological, structural, chemical, optical and transport properties have been thoroughly characterized by a number of different microscopies, transport and spectroscopic techniques. Though disorder and segregation into C-rich and h-BN-rich domains have been observed in ultrathin flat few layers, high doping levels have been reached, inducing strong modifications of the electronic, optical and transport properties of C-rich and h-BN-rich phases. This synthesis procedure can open new routes towards the achievement of homogeneous highly mixed ternary B-C-N phase
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