Implementing a Successful Collaborative Learning Environment

This action research report summarizes a study of 65 diverse student learners in a 10th grade AP US History class. This research investigates the implementation of a collaborative learning environment to elicit positive effects on student attitudes toward learning and their achievement. To gain pre-intervention data, students were surveyed on their attitudes and took multiple-choice assessments. During the intervention period, students completed surveys regarding the effectiveness of the collaborative learning implementation and completed multiple-choice assessments. After the interventions, students were surveyed again on their attitudes toward learning. The results demonstrated insignificant effects on student attitudes but improvements in student achievement. Data supports concluding that collaborative learning may impact student retention of content and learning objectives. Future research may indicate whether the execution of such interventions over a longer period of time would have more considerable outcomes in the areas of retention or student attitudes about learning

A Zebrafish Model for Studies on Esophageal Epithelial Biology

Mammalian esophagus exhibits a remarkable change in epithelial structure during the transition from embryo to adult. However, the molecular mechanisms of esophageal epithelial development are not well understood. Zebrafish (Danio rerio), a common model organism for vertebrate development and gene function, has not previously been characterized as a model system for esophageal epithelial development. In this study, we characterized a piece of non-keratinized stratified squamous epithelium similar to human esophageal epithelium in the upper digestive tract of developing zebrafish. Under the microscope, this piece was detectable at 5dpf and became stratified at 7dpf. Expression of esophageal epithelial marker genes (Krt5, P63, Sox2 and Pax9) was detected by immunohistochemistry and in situ hybridization. Knockdown of P63, a gene known to be critical for esophageal epithelium, disrupted the development of this epithelium. With this model system, we found that Pax9 knockdown resulted in loss or disorganization of the squamous epithelium, as well as down-regulation of the differentiation markers Krt4 and Krt5. In summary, we characterized a region of stratified squamous epithelium in the zebrafish upper digestive tract which can be used for functional studies of candidate genes involved in esophageal epithelial biology

Frequent use of paracetamol and risk of allergic disease among women in an Ethiopian population

Introduction The hypothesis that paracetamol might increase the risk of asthma and other allergic diseases have gained support from a range of independent studies. However, in studies based in developed countries, the possibility that paracetamol and asthma are associated through aspirin avoidance is difficult to exclude. Objectives To explore this hypothesis among women in a developing country, where we have previously reported aspirin avoidance to be rare. Methods In 2005/6 a population based cohort of 1065 pregnant women was established in Butajira, Ethiopia and baseline demographic data collected. At 3 years post birth, an interview-based questionnaire administered to 945 (94%) of these women collected data on asthma, eczema, and hay fever in the past 12 month, frequency of paracetamol use and potential confounders. Allergen skin tests to Dermatophagoides pteronyssinus and cockroach were also performed. The independent effects of paracetamol use on allergic outcomes were determined using multiple logistic regression analysis. Findings The prevalence of asthma, eczema and hay fever was 1.7%, 0.9% and 3.8% respectively; of any one of these conditions 5.5%, and of allergen sensitization 7.8%. Paracetamol use in the past month was reported by 29%, and associations of borderline significance were seen for eczema (adjusted OR (95% CI) = 8.51 (1.68 to 43.19) for 1–3 tablets and 2.19 (0.36 to 13.38) for ≥4 tablets, compared to no tablets in the past month; overall p = 0.055) and for ‘any allergic condition’ (adjusted OR (95% CI) = 2.73 (1.22 to 6.11) for 1–3 tablets and 1.35 (0.67 to 2.70) for ≥4 tablets compared to 0 in the past month; overall p = 0.071). Conclusions This study provides further cross-sectional evidence that paracetamol use increases the risk of allergic disease

Personalized and targeted therapy of esophageal squamous cell carcinoma: an update: Personalized and targeted therapy of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a deadly disease that requires extensive research. In this review, we update recent progress in the research area of targeted therapy for ESCC. Sox2 and its associated proteins (e.g., ΔNp63α), which regulate lineage survival of ESCC cells, are proposed as therapeutic targets. It is believed that targeting the lineage-survival mechanism may be more effective than targeting other mechanisms. With the advent of a new era of personalized targeted therapy, there is a need to move from the tumor-centric model into an organismic model

Racial and Ethnic Differences in Injury Prevention Behaviors Among Caregivers of Infants

African American and Latino children experience higher rates of traumatic injury and mortality, but the extent to which parents of different races and ethnicities disparately enact injury prevention behaviors has not been fully characterized. The objective of this study is to evaluate the association between caregiver race/ethnicity and adherence to injury prevention recommendations

A new CY elliptic fibration and tadpole cancellation

Tadpole cancellation in Sen limits in F-theory was recently studied by Aluffi and Esole. We extend their results, generalizing the elliptic fibrations they used and obtaining a new case of universal tadpole cancellation, at least numerically. We could not find an actual Sen limit having the correct brane content, and we argue that such a limit may not exist. We also give a uniform description of the fibration used by Aluffi and Esole as well as a new, simple, fibration which has non-Kodaira type fibers.Comment: 18 pages; added references and minor change

Portfolio selection problems in practice: a comparison between linear and quadratic optimization models

Several portfolio selection models take into account practical limitations on the number of assets to include and on their weights in the portfolio. We present here a study of the Limited Asset Markowitz (LAM), of the Limited Asset Mean Absolute Deviation (LAMAD) and of the Limited Asset Conditional Value-at-Risk (LACVaR) models, where the assets are limited with the introduction of quantity and cardinality constraints. We propose a completely new approach for solving the LAM model, based on reformulation as a Standard Quadratic Program and on some recent theoretical results. With this approach we obtain optimal solutions both for some well-known financial data sets used by several other authors, and for some unsolved large size portfolio problems. We also test our method on five new data sets involving real-world capital market indices from major stock markets. Our computational experience shows that, rather unexpectedly, it is easier to solve the quadratic LAM model with our algorithm, than to solve the linear LACVaR and LAMAD models with CPLEX, one of the best commercial codes for mixed integer linear programming (MILP) problems. Finally, on the new data sets we have also compared, using out-of-sample analysis, the performance of the portfolios obtained by the Limited Asset models with the performance provided by the unconstrained models and with that of the official capital market indices

Neutron Majorana mass from exotic instantons

We show how a Majorana mass for the Neutron could result from non-perturbative quantum gravity effects peculiar to string theory. In particular, "exotic instantons" in un-oriented string compactifications with D-branes extending the (supersymmetric) standard model could indirectly produce an effective operator delta{m} n^t n+h.c. In a specific model with an extra vector-like pair of `quarks', acquiring a large mass proportional to the string mass scale (exponentially suppressed by a function of the string moduli fields), delta{m} can turn out to be as low as 10^{-24}-10^{-25} eV. The induced neutron-antineutron oscillations could take place with a time scale tau_{n\bar{n}} > 10^8 s, that could be tested by the next generation of experiments. On the other hand, proton decay and FCNC's are automatically strongly suppressed and are compatible with the current experimental limits. Depending on the number of brane intersections, the model may also lead to the generation of Majorana masses for R-handed neutrini. Our proposal could also suggest neutron-neutralino or neutron-axino oscillations, with implications in UCN, Dark Matter Direct Detection, UHECR and Neutron-Antineutron oscillations. This suggests to improve the limits on neutron-antineutron oscillations, as a possible test of string theory and quantum gravity.Comment: 35 pages, 11 figures. More comments on neutron-neutralino mixin