An Educational Reconstruction of Special Relativity Theory for Secondary Education.

Einstein’s derivation of special relativity theory (SRT), based on hypothetical reasoning and thought experiments, is regarded as a prime example of physics theory development. In secondary education, the introduction of SRT could provide a great opportunity for students to engage in physics theorizing, but this opportunity is largely being missed in current teaching practice. One reason could be that secondary students lack some knowledge of electromagnetism that was central to Einstein’s argument. Therefore, we conducted an educational reconstruction to develop a teaching approach that would not rely on advanced understanding of electromagnetism, yet retain the modes of reasoning that were characteristic of Einstein’s approach. In our reconstruction, we identified the light postulate, which is notoriously difficult for students to grasp, as a central concept. We developed a teaching and learning sequence in which students perform relativistic thought experiments and try different interpretations of the light postulate. Through these activities, students experienced how the new concepts meet the requirements for a good theory. Experimental evaluation of the teaching and learning sequence indicates that this can be a fruitful approach to introduce SRT to secondary students

Atosiban versus fenoterol as a uterine relaxant for external cephalic version: randomised controlled trial

Objective To compare the effectiveness of the oxytocin receptor antagonist atosiban with the beta mimetic fenoterol as uterine relaxants in women undergoing external cephalic version (ECV) for breech presentation. Design Multicentre, open label, randomised controlled trial. Setting Eight hospitals in the Netherlands, August 2009 to May 2014. Participants 830 women with a singleton fetus in breech presentation and a gestational age of more than 34 weeks were randomly allocated in a 1:1 ratio to either 6.75 mg atosiban (n=416) or 40 μg fenoterol (n=414) intravenously for uterine relaxation before ECV. Main outcome measures The primary outcome measures were a fetus in cephalic position 30 minutes after the procedure and cephalic presentation at delivery. Secondary outcome measures were mode of delivery, incidence of fetal and maternal complications, and drug related adverse events. All analyses were done on an intention-to-treat basis. Results Cephalic position 30 minutes after ECV occurred significantly less in the atosiban group than in the fenoterol group (34% v 40%, relative risk 0.73, 95% confidence interval 0.55 to 0.93). Presentation at birth was cephalic in 35% (n=139) of the atosiban group and 40% (n=166) of the fenoterol group (0.86, 0.72 to 1.03), and caesarean delivery was performed in 60% (n=240) of women in the atosiban group and 55% (n=218) in the fenoterol group (1.09, 0.96 to 1.20). No significant differences were found in neonatal outcomes or drug related adverse events. Conclusions In women undergoing ECV for breech presentation, uterine relaxation with fenoterol increases the rate of cephalic presentation 30 minutes after the procedure. No statistically significant difference was found for cephalic presentation at delivery

Event diagrams: Supporting student reasoning in special relativity through thought experiments

This chapter presents event diagrams as a representational tool that allows students to visualize relativistic phenomena. It puts particular emphasis on thought experiments that can help students obtain a deeper understanding of physical phenomena that are hard to imagine. The chapter is intended for readers who look for instructional models to teach concepts of special relativity at the secondary school level, and also, for those who wish to learn more about thought experiments as instructional tools. Students perform the thought experiment by drawing light propagation in the event diagram. Compared to the traditional presentation of thought experiments, the event diagram stimulates students to reason with light propagation more explicitly. Like all external representations, event diagrams are a simplified and idealized display of reality and are inherently limited. To wrap up, the authors have shown how their tasks stimulate students to perform thought experiments by drawing light propagation in event diagrams

Comprehensive Detection of Genomic Duplications and Deletions in the DMD Gene, by Use of Multiplex Amplifiable Probe Hybridization

Duplications and deletions are known to cause a number of genetic disorders, yet technical difficulties and financial considerations mean that screening for these mutations, especially duplications, is often not performed. We have adapted multiplex amplifiable probe hybridization (MAPH) for the screening of the DMD gene, mutations in which cause Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy. MAPH involves the quantitative recovery of specifically designed probes following hybridization to immobilized genomic DNA. We have engineered probes for each of the 79 exons of the DMD gene, and we analyzed them by using a 96-capillary sequencer. We screened 24 control individuals, 102 patients, and 23 potential carriers and detected a large number of novel rearrangements, especially small, one- and two-exon duplications. A duplication of exon 2 alone was the most frequently occurring mutation identified. Our analysis indicates that duplications occur in 6% of patients with DMD. The MAPH technique as modified here is simple, quick, and accurate; furthermore, it is based on existing technology (i.e., hybridization, PCR, and electrophoresis) and should not require new equipment. Together, these features should allow easy implementation in routine diagnostic laboratories. Furthermore, the methodology should be applicable to any genetic disease, it should be easily expandable to cover >200 probes, and its characteristics should facilitate high-throughput screening

Atosiban versus fenoterol as a uterine relaxant for external cephalic version: randomised controlled trial

To compare the effectiveness of the oxytocin receptor antagonist atosiban with the beta mimetic fenoterol as uterine relaxants in women undergoing external cephalic version (ECV) for breech presentation. Multicentre, open label, randomised controlled trial. Eight hospitals in the Netherlands, August 2009 to May 2014. 830 women with a singleton fetus in breech presentation and a gestational age of more than 34 weeks were randomly allocated in a 1:1 ratio to either 6.75 mg atosiban (n=416) or 40 μg fenoterol (n=414) intravenously for uterine relaxation before ECV. The primary outcome measures were a fetus in cephalic position 30 minutes after the procedure and cephalic presentation at delivery. Secondary outcome measures were mode of delivery, incidence of fetal and maternal complications, and drug related adverse events. All analyses were done on an intention-to-treat basis. Cephalic position 30 minutes after ECV occurred significantly less in the atosiban group than in the fenoterol group (34% v 40%, relative risk 0.73, 95% confidence interval 0.55 to 0.93). Presentation at birth was cephalic in 35% (n=139) of the atosiban group and 40% (n=166) of the fenoterol group (0.86, 0.72 to 1.03), and caesarean delivery was performed in 60% (n=240) of women in the atosiban group and 55% (n=218) in the fenoterol group (1.09, 0.96 to 1.20). No significant differences were found in neonatal outcomes or drug related adverse events. In women undergoing ECV for breech presentation, uterine relaxation with fenoterol increases the rate of cephalic presentation 30 minutes after the procedure. No statistically significant difference was found for cephalic presentation at delivery. Dutch Trial Register, NTR 187

Coffin-Siris syndrome and the BAF complex: genotype-phenotype study in 63 patients

Item does not contain fulltextDe novo germline variants in several components of the SWI/SNF-like BAF complex can cause Coffin-Siris syndrome (CSS), Nicolaides-Baraitser syndrome (NCBRS), and nonsyndromic intellectual disability. We screened 63 patients with a clinical diagnosis of CSS for these genes (ARID1A, ARID1B, SMARCA2, SMARCA4, SMARCB1, and SMARCE1) and identified pathogenic variants in 45 (71%) patients. We found a high proportion of variants in ARID1B (68%). All four pathogenic variants in ARID1A appeared to be mosaic. By using all variants from the Exome Variant Server as test data, we were able to classify variants in ARID1A, ARID1B, and SMARCB1 reliably as being pathogenic or nonpathogenic. For SMARCA2, SMARCA4, and SMARCE1 several variants in the EVS remained unclassified, underlining the importance of parental testing. We have entered all variant and clinical information in LOVD-powered databases to facilitate further genotype-phenotype correlations, as these will become increasingly important because of the uptake of targeted and untargeted next generation sequencing in diagnostics. The emerging phenotype-genotype correlation is that SMARCB1 patients have the most marked physical phenotype and severe cognitive and growth delay. The variability in phenotype seems most marked in ARID1A and ARID1B patients. Distal limbs anomalies are most marked in ARID1A patients and least in SMARCB1 patients. Numbers are small however, and larger series are needed to confirm this correlation