Evaluation of some scale effects in the response and failure of composite beams

The feasibility of using scale model testing for predicting full-scale behavior of composite beams loaded in tension and flexure was investigated. Classical laws of similitude were applied to fabricate and test replica model beams to identify scaling effects in the load response, strength, and mode of failure. Experiments were conducted using graphite-epoxy composite beams having different laminate stacking sequences and a range of scaled sizes. Results indicated that the elastic response of scaled composite beams was independent of specimen size. However, a significant scale effect in strength was observed. In addition, a transition in failure mode was observed among scaled beams of certain laminate stacking sequences. Weibull statistical and fracture mechanics based models were applied to predict the strength scale effect since standard failure criteria cannot account for the influence of absolute specimen size in failure

Novice Teachers: Do They Use What We Teach Them?

Teacher educators frequently engage in some rather agonizing soul searching regarding their effectiveness in preparing preservice teachers. Students pass through their classes, go on to other classes, and eventually they are in the real world of the classroom. Teacher educators seldom get direct feedback from students as to the relevance or the value of the instruction they received. Lacking this feedback, teacher educators who teach from a whole language perspective frequently question whether students actually use the instructional strategies they were taught in their reading courses, or whether they choose the more traditional basal reader approach

Arkansas Teacher Licensure Cut Scores, Do They Indicate Highly Qualified Teachers?

The highly qualified provision of the 2001 No Child Left Behind Act promoted licensure exams on a national level. The present study is an effort to explore the most commonly used Praxis licensure exams and their passing scores. Hypothesized was that passing scores are set at such a minimal level that they are ineffectual in identifying highly qualified teachers. More specifically, Arkansas\u27s low passing scores are examined by comparing the distribution of University of Arkansas Praxis scores to national trends. Based on low passing scores, the question was posed - At what point in teachers\u27 careers are expectations lessened? Academic data from Elementary Education graduates of the University of Arkansas College of Education and Health Professions were compared to colleagues with the conjecture that they would fall below. Finally, as the reauthorization of No Child Left Behind looms, the mandate for highly qualified teachers has become energized with the call for effective teachers. Student gains data of relatively new teachers from a local district were regressed on teacher scores on content knowledge exams as well as years of experience to explore the relationships. SEA passing scores were found to be low with all but a few exceptions using cut scores for licensure exams below the median of the national testing pool. Further, University of Arkansas testers, replicated national trends in scoring on Praxis exams eliminating any justification for Arkansas employing minimal standards. As conjectured, Elementary Education graduates of the U of A presented academic credentials below that of colleagues thus exacerbating the highly qualified conundrum. Lastly, the attempt to connect student achievement to teacher content knowledge through Praxis exam scores and years of experience proved unsuccessful. Higher standards, particularly for Elementary Education graduates, were discussed in the context of the Common Core State Standards and the push for effective teaching

A life marketed as fiction : An analysis of the work of Eliza Parsons.

No abstract provided

Test Fixture for Determination of Energy Absorbing Capabilities of Composite Materials

The present invention provides a fixture for supporting an elongated specimen for crush testing. The fixture comprises a base plate. four guiding rods, a sliding plate, four support rods and two collars. The guiding rods connect to the base plate and extend in a direction substantially perpendicular to the base plate. The sliding plate has linear bearings which encircle the guiding rods and enable translation of the sliding plate along the axis of each guiding rod. The four supporting rods mount to the base plate and also extend in a direction substantially perpendicular to the base plate. Each support rod has a keyway for a wedge which contacts the elongated specimen and holds the specimen in place during crushing. Each collar lies above the sliding plate and holds a pair of support rods on their ends opposite the ends connected to the base plate. A spherical bearing sits on top of the sliding plate and transfers an applied load to the sliding plate, which moves downward and crushes the elongated specimen

Test fixture for determination of energy absorbing capabilities of composite materials

The present invention provides a fixture for supporting an elongated specimen for crush testing. The fixture comprises a base plate, four guiding rods, a sliding plate, four support rods and two collars. The guiding rods connect to the base plate and extend in a direction substantially perpendicular to the base plate. The sliding plate has linear bearings which encircle the guiding rods and enable translation of the sliding plate along the axis of each guiding rod. The four supporting rods mount to the base plate and also extend in a direction substantially perpendicular to the base plate. Each support rod has a keyway for a wedge which contacts the elongated specimen and holds the specimen in place during crushing. Each collar lies above the sliding plate and holds a pair of support rods on their ends opposite the ends connected to the base plate. A spherical bearing sits on top of the sliding plate and transfers an applied load to the sliding plate, which moves downward and crushes the elongated specimen

Driving difficulties in patients with axial spondyloarthritis : Results from the Scotland Registry for Ankylosing Spondylitis

Acknowledgements The authors thank all of the clinicians and research nurses who facilitated recruitment and data collection, and the SIRAS steering committee in particular, especially Professor Roger Sturrock (chair) and Dr David Marshall (vice‐chair). The authors also thank the SIRAS coordinating centre study team, particularly Elizabeth Ferguson‐Jones, Giles O'Donovan, Nabi Moaven‐Hashemi, and Flora Joyce. Funding: AbbVie and Pfizer financially supported the Scotland Registry for Ankylosing Spondylitis (SIRAS). AbbVie and Pfizer had no role in the study design or in the collection, analysis, or interpretation of the data, the writing of the manuscript, or the decision to submit the manuscript for publication. Publication of this article was not contingent upon approval by AbbVie or by Pfizer. LM is funded through the Medical Research Council/Versus Arthritis Centre for Musculoskeletal Health and Work (Versus Arthritis Grant No. 20665).Peer reviewedPostprin

Loss of huntingtin function slows synaptic vesicle endocytosis in striatal neurons from the httQ140/Q140 mouse model of Huntington's disease

Huntington\u27s disease (HD) is caused by CAG repeat expansion within the HTT gene, with the dysfunction and eventual loss of striatal medium spiny neurons a notable feature. Since medium spiny neurons receive high amounts of synaptic input, we hypothesised that this vulnerability originates from an inability to sustain presynaptic performance during intense neuronal activity. To test this hypothesis, primary cultures of either hippocampal or striatal neurons were prepared from either wild-type mice or a knock-in HD mouse model which contains 140 poly-glutamine repeats in the huntingtin protein (htt(Q140/Q140)). We identified a striatum-specific defect in synaptic vesicle (SV) endocytosis in htt(Q140/Q140) neurons that was only revealed during high frequency stimulation. This dysfunction was also present in neurons that were heterozygous for the mutant HTT allele. Depletion of endogenous huntingtin using hydrophobically-modified siRNA recapitulated this activity-dependent defect in wild-type neurons, whereas depletion of mutant huntingtin did not rescue the effect in htt(Q140/Q140) neurons. Importantly, this SV endocytosis defect was corrected by overexpression of wild-type huntingtin in homozygous htt(Q140/Q140) neurons. Therefore, we have identified an activity-dependent and striatum-specific signature of presynaptic dysfunction in neurons derived from pre-symptomatic HD mice, which is due to loss of wild-type huntingtin function. This presynaptic defect may render this specific neuronal subtype unable to operate efficiently during high frequency activity patterns, potentially resulting in dysfunctional neurotransmission, synapse failure and ultimately degeneration