Heat-transfer distributions on biconics at incidence in hypersonic-hypervelocity He, N2, air, and CO2 flows

Laminar heat transfer rates were measured on spherically blunted, 13 deg/7 deg on axis and bent biconics (fore cone bent 7 deg upward relative to aft cone) at hypersonic hypervelocity flow conditions in the Langley Expansion Tube. Freestream velocities from 4.5 to 6.9 km/sec and Mach numbers from 6 to 9 were generated using helium, nitrogen, air, and carbon dioxide test gases, resulting in normal shock density ratios from 4 to 19. Angle of attack, referenced to the axis of the aft cone, was varied from 0 to 20 deg in 4 deg increments. The effect of nose bend, angle of attack, and real gas phenomena on heating distributions are presented along with comparisons of measurement to prediction from a code which solves the three dimensional parabolized Navier-Stokes equations

Asymmetric magnetic reconnection with a flow shear and applications to the magnetopause

We perform a theoretical and numerical study of anti-parallel 2D magnetic reconnection with asymmetries in the density and reconnecting magnetic field strength in addition to a bulk flow shear across the reconnection site in the plane of the reconnecting fields, which commonly occurs at planetary magnetospheres. We predict the speed at which an isolated X-line is convected by the flow, the reconnection rate, and the critical flow speed at which reconnection no longer takes place for arbitrary reconnecting magnetic field strengths, densities, and upstream flow speeds, and confirm the results with two-fluid numerical simulations. The predictions and simulation results counter the prevailing model of reconnection at Earth's dayside magnetopause which says reconnection occurs with a stationary X-line for sub-Alfvenic magnetosheath flow, reconnection occurs but the X-line convects for magnetosheath flows between the Alfven speed and double the Alfven speed, and reconnection does not occur for magnetosheath flows greater than double the Alfven speed. We find that X-line motion is governed by momentum conservation from the upstream flows, which are weighted differently in asymmetric systems, so the X-line convects for generic conditions including sub-Alfvenic upstream speeds. For the reconnection rate, while the cutoff condition for symmetric reconnection is that the difference in flows on the two sides of the reconnection site is twice the Alfven speed, we find asymmetries cause the cutoff speed for asymmetric reconnection to be higher than twice the asymmetric form of the Alfven speed. The results compare favorably with an observation of reconnection at Earth's polar cusps during a period of northward interplanetary magnetic field, where reconnection occurs despite the magnetosheath flow speed being more than twice the magnetosheath Alfven speed, the previously proposed suppression condition.Comment: 46 pages, 7 figures, abstract abridged here, accepted to Journal of Geophysical Research - Space Physic

Developing coaches for mathematical resilience: level 2

The construct ‘Mathematical Resilience’ [1] has been developed to describe a positive stance towards mathematics that enables learners to develop approaches to mathematical learning which allow them to overcome the barriers and setbacks that are frequently part of learning mathematics for many people. A resilient stance towards mathematics can be engineered by a strategic and explicit focus on the culture of learning mathematics within both formal and informal learning environments. As part of that cultural engineering, we have developed the notion of coaches specifically to support emergent resilience. The work described here is focused on developing coaches who can work beside learners, helping them to conjecture and use resilient learning ideas when facing difficulties in mathematics. Coaches develop a culture of ‘can do’ mathematics which works to counter the prevalent culture of mathematics helplessness and mathematics anxiety in the general population when faced with mathematical ideas. The coaches are not required to know the answer but rather to know ways that might yield an understanding of the mathematical ideas involved and thus lead to an answer. Our previous paper described the outcomes of the level 1 course, in which participants became skilled at peer-coaching. This paper discusses the outcomes of a second pilot course (Sept to Nov 2013) designed to develop ‘coaches for mathematical resilience’ at level 2, equipped to work with learners under the direction of a mathematics tutor outside the course. The 10 participants at Level 2, who regularly work with apprentices, both young and more mature, in a work-based environment continued with part 2 of the programme because of the positive outcomes from level 1. In the Level 1 course, they had worked to develop their knowledge of how to overcome deep seated antipathy to mathematics in themselves and in those with whom they work. The data confirms that once an individual has begun to develop their own personal mathematical resilience, worked through their own anxieties and negative stance towards mathematics in a safe and collaborative environment, they can then successfully coach learners to develop as resilient learners of mathematics. They become able to help those learners to find or develop the resources and skills to overcome their own barriers to learning mathematics and to manage any anxiety that may be engendered. Importantly, when the coach learns not to take any responsibility for the mathematics, but rather to focus on the learning skills and well-being of the learner, t learner outcomes are improved

Evaluation of the finger wrinkling test: a pilot study

Purpose: Tilt table testing mainly evaluates the systemic cardiovascular part of the autonomic nervous system, while it is assumed that the finger wrinkling test assesses the peripheral part of the autonomic nervous system. In this study we explored whether the finger wrinkling test could be a useful test for autonomic dysfunction and whether the clinical evaluation of wrinkling can be improved by digital analysis of photographs. Methods: As much as 20 healthy subjects and 15 patients underwent tilt table testing and finger wrinkling testing. During the finger wrinkling test the right hand was immersed in water at 40°C. The degree of wrinkling was assessed with a 5-point clinical scale at baseline, 5, 15 and 30 min of immersion. Photographs were taken at the same intervals. Several features were evaluated using digital analysis: length and gradient of automatically detected wrinkle and mean, maximum, minimum, variance and derivative of grey value of pixels. Results: Clinical scoring of wrinkling allowed differentiation between healthy subjects and patients with a normal and an abnormal response to tilt table testing. Relevant features obtained with digital analysis were mean grey value and the gradient of automatically detected wrinkle. McNemar’s test showed no difference in test results between the tilt table test and the finger wrinkling test with a kappa of 0.68. Conclusion: The finger wrinkling test can be used as a screening test before tilt table testing. Visual evaluation of wrinkling is still superior to digital analysis of photographs

Is Dentistry at Risk? A Case for Interprofessional Education

The goal of interprofessional education (IPE) is to bring various professional groups together in the educational environment to promote collaborative practice and improve the health care of patients. Interest in IPE has been sparked by several factors in the health care system, including the increased awareness of oral-systemic connections, an aging population, the shift of the burden of illness from acute to chronic care, and lack of access to basic oral care. Increasingly, since the publication of the U.S. surgeon general's report in 2000, the dialogue surrounding IPE in dentistry has escalated. But how has dentistry changed regarding IPE since the report was released? This position paper argues that little has changed in the way dental students are taught and prepared to participate in IPE. The authors contend that academic dentistry and organized dentistry must take the lead in initiating and demanding IPE if dental students are to be prepared to work in the health care environment of the twenty-first century. Included are reasons why IPE is necessary and why dentistry must lead the conversation and participate in the solution to the oral health care crisis. It explores existing models and alternate approaches to IPE, barriers to implementation, and proposed strategies for academic institutions

Androgen receptor as a mediator and biomarker of radioresistance in triple-negative breast cancer.

Increased rates of locoregional recurrence have been observed in triple-negative breast cancer despite chemotherapy and radiation therapy. Thus, approaches that combine therapies for radiosensitization in triple-negative breast cancer are critically needed. We characterized the radiation therapy response of 21 breast cancer cell lines and paired this radiation response data with high-throughput drug screen data to identify androgen receptor as a top target for radiosensitization. Our radiosensitizer screen nominated bicalutamide as the drug most effective in treating radiation therapy-resistant breast cancer cell lines. We subsequently evaluated the expression of androgen receptor in >2100 human breast tumor samples and 51 breast cancer cell lines and found significant heterogeneity in androgen receptor expression with enrichment at the protein and RNA level in triple-negative breast cancer. There was a strong correlation between androgen receptor RNA and protein expression across all breast cancer subtypes (R2 = 0.72, p < 0.01). In patients with triple-negative breast cancer, expression of androgen receptor above the median was associated with increased risk of locoregional recurrence after radiation therapy (hazard ratio for locoregional recurrence 2.9-3.2)) in two independent data sets, but there was no difference in locoregional recurrence in triple-negative breast cancer patients not treated with radiation therapy when stratified by androgen receptor expression. In multivariable analysis, androgen receptor expression was most significantly associated with worse local recurrence-free survival after radiation therapy (hazard ratio of 3.58) suggesting that androgen receptor expression may be a biomarker of radiation response in triple-negative breast cancer. Inhibition of androgen receptor with MDV3100 (enzalutamide) induced radiation sensitivity (enhancement ratios of 1.22-1.60) in androgen receptor-positive triple-negative breast cancer lines, but did not affect androgen receptor-negative triple-negative breast cancer or estrogen-receptor-positive, androgen receptor-negative breast cancer cell lines. androgen receptor inhibition with MDV3100 significantly radiosensitized triple-negative breast cancer xenografts in mouse models and markedly delayed tumor doubling/tripling time and tumor weight. Radiosensitization was at least partially dependent on impaired dsDNA break repair mediated by DNA protein kinase catalytic subunit. Our results implicate androgen receptor as a mediator of radioresistance in breast cancer and identify androgen receptor inhibition as a potentially effective strategy for the treatment of androgen receptor-positive radioresistant tumors

Hodge Theory on Metric Spaces

Hodge theory is a beautiful synthesis of geometry, topology, and analysis, which has been developed in the setting of Riemannian manifolds. On the other hand, spaces of images, which are important in the mathematical foundations of vision and pattern recognition, do not fit this framework. This motivates us to develop a version of Hodge theory on metric spaces with a probability measure. We believe that this constitutes a step towards understanding the geometry of vision. The appendix by Anthony Baker provides a separable, compact metric space with infinite dimensional \alpha-scale homology.Comment: appendix by Anthony W. Baker, 48 pages, AMS-LaTeX. v2: final version, to appear in Foundations of Computational Mathematics. Minor changes and addition

Natural Bacterial Communities Serve as Quantitative Geochemical Biosensors

Biological sensors can be engineered to measure a wide range of environmental conditions. Here we show that statistical analysis of DNA from natural microbial communities can be used to accurately identify environmental contaminants, including uranium and nitrate at a nuclear waste site. In addition to contamination, sequence data from the 16S rRNA gene alone can quantitatively predict a rich catalogue of 26 geochemical features collected from 93 wells with highly differing geochemistry characteristics. We extend this approach to identify sites contaminated with hydrocarbons from the Deepwater Horizon oil spill, finding that altered bacterial communities encode a memory of prior contamination, even after the contaminants themselves have been fully degraded. We show that the bacterial strains that are most useful for detecting oil and uranium are known to interact with these substrates, indicating that this statistical approach uncovers ecologically meaningful interactions consistent with previous experimental observations. Future efforts should focus on evaluating the geographical generalizability of these associations. Taken as a whole, these results indicate that ubiquitous, natural bacterial communities can be used as in situ environmental sensors that respond to and capture perturbations caused by human impacts. These in situ biosensors rely on environmental selection rather than directed engineering, and so this approach could be rapidly deployed and scaled as sequencing technology continues to become faster, simpler, and less expensive