Persistence in Mathematics by Underrepresented Students: Experiences of a Math Excel Program

Success in mathematics by underrepresented and nontraditional college students is measured not only by academic performance (grades), but also by the continued participation and persistence of these students in mathematics coursework. The Math Excel program at Oregon State University attempts to build learning communities with a sharp academic focus in support of students concurrently taking introductory level mathematics courses. The Math Excel program is based heavily on Uri Treisman\u27s Emerging Scholars Workshop model of collaborative problem solving. In this article, we examine the experience of minority students in the Educational Opportunities Program participating in the Math Excel program. While the program had appeared successful in terms of improving academic performance in the concurrent mathematics course, the continued participation and persistence of these students in mathematics was disappointing. On a trial basis, structural changes were made to build a much stronger identification of the Math Excel learning community with a section of College Algebra. In the next term, there was a much higher incidence of participation in the subsequent Precalculus using the same Math Excel structure. While the collaborative problem solving activity provided in Math Excel was crucial to students\u27 successful academic performance, these results suggest that subtle issues related to students\u27 recognition of and identification with a learning community may be critically important to underrepresented and nontraditional students\u27 continued persistence in mathematics

A Handbook Developed to Create a Better Understanding of the Gifted

The problems encountered by gifted students when integrating into the regular self-contained classroom were studied. Parents and peers display their misunderstanding of gifted students by their innocent remarks that adversely affect them. Teachers unwittingly cause discomfort by the unchallenging tasks gifted children are expected to perform. Sixty children from the Wenatchee School District\u27s Gifted Pull-out Program were asked to share some of their concerns pertaining to these problems. Based upon their responses and a survey of the literature, a handbook was compiled to help prevent parents, teachers and peers from misunderstanding the gifted student

Age-dependent migration strategy in honey buzzards Pernis apivorus tracked by satellite

Six adult and three juvenile honey buzzards Pernis apivorus were radio-tracked by satellite during autumn migration from southwestern Sweden. All adults crossed the Mediterranean Sea at the Strait of Gibraltar and continued across the Sahara desert to winter in West Africa, from Sierra Leone to Cameroon. Analysing three main steps of the migration, (1) from the breeding site to the southern Mediterranean region, (2) across the Sahara and (3) from the southern Sahara to the wintering sites, the adults changed direction significantly between these steps, and migrated along a distinct large-scale detour. In contrast, the juveniles travelled in more southerly directions, crossed the Mediterranean Sea at various places, but still ended up in the same wintering areas as the adults. Average speeds maintained on travelling days were similar for the two age groups, about 170 km/day in Europe, 270 km/day across Sahara and 125 km/day in Africa south of Sahara. However, as the adults used fewer stopover days en route, they maintained higher mean overall speeds and completed migration in a shorter time (42 days) than the juveniles (64 days). Although the juveniles set out on more direct courses towards the wintering grounds, they did not cover significantly shorter distances than the adults, as they tended to show a larger directional scatter between shorter flight segments. The results corroborate previous suggestions that adult and juvenile honey buzzards follow different routes during autumn migration, and that the birds change migration strategy during their lifetime. While juveniles may use individual vector orientation, social influences and learning may be of great importance for the detour migration of adults. The remarkable and distinct age-dependent shift in migratory route and orientation of the honey buzzard provides a challenging evolutionary problem

Modeling effects of L-type ca(2+) current and na(+)-ca(2+) exchanger on ca(2+) trigger flux in rabbit myocytes with realistic T-tubule geometries.

The transverse tubular system of rabbit ventricular myocytes consists of cell membrane invaginations (t-tubules) that are essential for efficient cardiac excitation-contraction coupling. In this study, we investigate how t-tubule micro-anatomy, L-type Ca(2+) channel (LCC) clustering, and allosteric activation of Na(+)/Ca(2+) exchanger by L-type Ca(2+) current affects intracellular Ca(2+) dynamics. Our model includes a realistic 3D geometry of a single t-tubule and its surrounding half-sarcomeres for rabbit ventricular myocytes. The effects of spatially distributed membrane ion-transporters (LCC, Na(+)/Ca(2+) exchanger, sarcolemmal Ca(2+) pump, and sarcolemmal Ca(2+) leak), and stationary and mobile Ca(2+) buffers (troponin C, ATP, calmodulin, and Fluo-3) are also considered. We used a coupled reaction-diffusion system to describe the spatio-temporal concentration profiles of free and buffered intracellular Ca(2+). We obtained parameters from voltage-clamp protocols of L-type Ca(2+) current and line-scan recordings of Ca(2+) concentration profiles in rabbit cells, in which the sarcoplasmic reticulum is disabled. Our model results agree with experimental measurements of global Ca(2+) transient in myocytes loaded with 50 μM Fluo-3. We found that local Ca(2+) concentrations within the cytosol and sub-sarcolemma, as well as the local trigger fluxes of Ca(2+) crossing the cell membrane, are sensitive to details of t-tubule micro-structure and membrane Ca(2+) flux distribution. The model additionally predicts that local Ca(2+) trigger fluxes are at least threefold to eightfold higher than the whole-cell Ca(2+) trigger flux. We found also that the activation of allosteric Ca(2+)-binding sites on the Na(+)/Ca(2+) exchanger could provide a mechanism for regulating global and local Ca(2+) trigger fluxes in vivo. Our studies indicate that improved structural and functional models could improve our understanding of the contributions of L-type and Na(+)/Ca(2+) exchanger fluxes to intracellular Ca(2+) dynamics

Evidence for multiband superconductivity in the heavy fermion compound UNi2Al3

Epitaxial thin films of the heavy fermion superconductor UNi2Al3 with Tc{max}=0.98K were investigated. The transition temperature Tc depends on the current direction which can be related to superconducting gaps opening at different temperatures. Also the influence of the magnetic ordering at TN=5K on R(T) is strongly anisotropic indicating different coupling between the magnetic moments and itinerant charge carriers on the multi-sheeted Fermi surface. The upper critical field Hc2(T) suggests an unconventional spin-singlet superconducting state.Comment: 4 pages, 6 figures revised version: inset of fig. 2 changed, fig. 3 added accepted for pub. in Phys. Rev. Lett. (estimated 9/04

A Diverse Clinical-Based Practice in Teacher Education

The purpose of the study was to determine if offering a virtual clinical-based practice would affect teacher candidates’ level of confidence in teaching diverse students. During 2012-2014, data were collected using a pre- and post-Likert scale questionnaire. A paired two sample t-test was utilized to determine if there was a significant difference in mean scores from the pre- to the postquestionnaire. Increases were found in all questionnaire items with five of the items showing a significant increase at the α=.01 level. The results suggest that a virtual clinical-based practice may provide an authentic experience for teacher candidates, may lead teacher candidates to be become more aware and take a positive approach to students’ differences, and that the teacher candidates’ comfort level with unfamiliar situations posed by students from diverse backgrounds may increase. A future implication is that colleges of education may want to consider adding a virtual clinical-based practice to existing diversity education classes. However, more research needs to be conducted to determine if virtual clinical-based practices are equal to or better than on-site clinical-based practices in an attempt to increase teacher candidates’ levels of confidence in teaching diverse students

Can vector summation describe the orientation system of juvenile ospreys and honey buzzards? - An analysis of ring recoveries and satellite tracking

Juvenile bird migrants are generally believed to use a clock-and-compass migratory orientation strategy. According to such a strategy migrants accomplish their migration by flying a number of successive flight steps with direction and number of steps controlled by an endogenous programme. One powerful way of testing this is by comparing predictions from a model of such a strategy with observed patterns. We used data from ringing and satellite-based radio telemetry to investigate the orientation system of juvenile ospreys (Pandion haliaetus) and honey buzzards (Pernis apivorus) migrating from Sweden to tropical west Africa. The ring recoveries showed a much larger scatter in the orientation of ospreys than of honey buzzards, but there was only a slight such difference in the satellite tracks. These tracks of individuals of both species were rather straight with a high directional concentration per step. The honey buzzard. data showed a close fit to a simple vector summation model, which is expected if birds follow a clock-and-compass strategy. However, the osprey data did not fit such a simple model, as ring recoveries showed a significantly greater deviation at short distances than predicted on the basis of long distance data. Satellite tracking also indicated less concentrated orientation on short distances. The pattern observed for the osprey can generally be explained by an extended vector summation model, including an important element of pre-migration dispersal. The existence of extensive dispersal in the osprey stands in contrast to the apparent absence of such dispersal in the honey buzzard. The explanation for this difference between the species is unclear. The model of orientation by vector summation is very sensitive to the existence of differences in mean direction between individuals. Assuming such differences, as tentatively indicated by the satellite tracking data, makes simple compass orientation by vector summation inconsistent with the distribution of ring recoveries at long distances, with a high proportion of misoriented birds falling outside the normal winter range

1,3,5-Tris(pyridin-3-yl)-2,4-diaza­penta-1,4-diene

In the solid state, the structure of the title compound, C18H15N5, is stabilized by weak C—H⋯N interactions. Mol­ecules are arranged in layers parallel to the bc plane forming an inter­esting supra­molecular structure

H3K56me3 is a novel, conserved heterochromatic mark that largely but not completely overlaps with H3K9me3 in both regulation and localization.

Histone lysine (K) methylation has been shown to play a fundamental role in modulating chromatin architecture and regulation of gene expression. Here we report on the identification of histone H3K56, located at the pivotal, nucleosome DNA entry/exit point, as a novel methylation site that is evolutionary conserved. We identify trimethylation of H3K56 (H3K56me3) as a modification that is present during all cell cycle phases, with the exception of S-phase, where it is underrepresented on chromatin. H3K56me3 is a novel heterochromatin mark, since it is enriched at pericentromeres but not telomeres and is thereby similar, but not identical, to the localization of H3K9me3 and H4K20me3. Possibly due to H3 sequence similarities, Suv39h enzymes, responsible for trimethylation of H3K9, also affect methylation of H3K56. Similarly, we demonstrate that trimethylation of H3K56 is removed by members of the JMJD2 family of demethylases that also target H3K9me3. Furthermore, we identify and characterize mouse mJmjd2E and its human homolog hKDM4L as novel, functionally active enzymes that catalyze the removal of two methyl groups from trimethylated H3K9 and K56. H3K56me3 is also found in C. elegans, where it co-localizes with H3K9me3 in most, but not all, tissues. Taken together, our findings raise interesting questions regarding how methylation of H3K9 and H3K56 is regulated in different organisms and their functional roles in heterochromatin formation and/or maintenance

Hyperbaric Oxygen Therapy Alters Vascular Reactivity Independent of Elevations in ATP

Hyperbaric oxygen (HBO) is a pharmacologic therapy used treat a variety of medical conditions. The underlying mechanisms of HBOs effect on vascular reactivity are poorly understood. The purpose of this study was to record the acute effects of HBO on vascular reactivity and determine the potential role of ATP in mediating these effects. Porcine mesenteric arteries were dissected and mounted in isolated organ baths to record changes in tension in response to potassium chloride (KCl, 15-60 mM), phenylephrine (PHE, 10-7-10-4 M), and sodium nitroprusside (SNP, 10-7-10-4 M) following a 2-hour exposure to HBO (1.75 ATA). HBO augmented responses to KCl and PHE compared to control arteries exposed to room air or nitrogen at 1.75 ATA as well as to room air at 1 atm. When compared to the 1 ATA room air control, KCl-induced constriction was significantly increased for the HBO exposure. Treatment with HBO also augmented vascular responses to PHE and SNP relative to nitrogen, but not ambient air. We hypothesized that HBO increased ATP production in vascular smooth muscle leading to enhanced vascular reactivity. Consequently, ATP levels were measured in mesenteric arteries but no significant differences in ATP levels were observed regardless of hyperbaric treatment. Direct measurements of ATPs’ effects on porcine vasculature with and without hyperbaric treatment resulted in no significant findings. These results suggest that HBO alters vascular reactivity independent of elevations in ATP