535 research outputs found

    Exploring Video Feedback in Philosophy

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    This paper explores the benefits of video feedback for teaching philosophy. Our analysis, based on results from a self-report student survey along with our own experience, indicates that video feedback possesses a number of advantages over traditional written comments. In particular we argue that video feedback is conducive to providing high-quality formative feedback, increases detail and clarity, and promotes student engagement. In addition, we argue that the advantages of video feedback make the method an especially apt tool for addressing challenges germane to teaching philosophy. Video feedback allows markers to more easily explain and illustrate philosophical goals and methods. It allows markers to model the doing of philosophy and thereby helps students to see philosophy’s value. Video feedback is a promising tool for addressing both cognitive and affective barriers to learning philosophy. Such advantages are especially valuable in the context of a student-centered, intentional learning framework. In light of these advantages, we find that video feedback is underappreciated and underutilized

    Resistively Detected NMR in Quantum Hall States: Investigation of the anomalous lineshape near ν=1\nu=1

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    A study of the resistively detected nuclear magnetic resonance (RDNMR) lineshape in the vicinity of ν=1\nu=1 was performed on a high-mobility 2D electron gas formed in GaAs/AlGaAs. In higher Landau levels, application of an RF field at the nuclear magnetic resonance frequency coincides with an observed minimum in the longitudinal resistance, as predicted by the simple hyperfine interaction picture. Near ν=1\nu=1 however, an anomalous dispersive lineshape is observed where a resistance peak follows the usual minimum. In an effort to understand the origin of this anomalous peak we have studied the resonance under various RF and sample conditions. Interestingly, we show that the lineshape can be completely inverted by simply applying a DC current. We interpret this as evidence that the minima and maxima in the lineshape originate from two distinct mechanisms.Comment: 5 pages, 3 figures, EP2DS 17, to be published in Physica

    Cable Suspended Structure-Antanas Panavas

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    This project is based on a roof system designed by Antanas Panavas. The design of the structure is a cable supported roof system that includes nonprismatic glulam beams. The structure itself is a self stressed system that has never been constructed and is still in the analysis stage. Project included analysis of the structure and a detailed process of how to model cables using SAP2000

    Asymptotic forms for hard and soft edge general β\beta conditional gap probabilities

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    An infinite log-gas formalism, due to Dyson, and independently Fogler and Shklovskii, is applied to the computation of conditioned gap probabilities at the hard and soft edges of random matrix β\beta-ensembles. The conditioning is that there are nn eigenvalues in the gap, with ntn \ll |t|, tt denoting the end point of the gap. It is found that the entropy term in the formalism must be replaced by a term involving the potential drop to obtain results consistent with known asymptotic expansions in the case n=0n=0. With this modification made for general nn, the derived expansions - which are for the logarithm of the gap probabilities - are conjectured to be correct up to and including terms O(logt)(\log|t|). They are shown to satisfy various consistency conditions, including an asymptotic duality formula relating β\beta to 4/β4/\beta.Comment: Replaces v2 which contains typographical errors arising from a previous unpublished draf

    Blowing Off STE(A)M: The Value of the Creative Arts for Gifted STEM Students (IAGC 2017)

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    The following is a collection of teaching documents, including classroom activities and assignment prompts, used in the Illinois Mathematics and Science Academy’s Graphic Novels, Creative Writing, and Modern Theater classes. These materials are easily included in courses with broader topical focuses, however, either as single-day activities or units of study. The specific materials included here are especially beneficial as means of encouraging student creativity, building up a variety of communication skills, rewarding experimental work, and providing new outlets for critical thinking and social-emotional development

    Diagenesis of Lower Cretaceous Pelagic Carbonates, North Atlantic: Paleoceanographic Signals Obscured

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    The stable isotope and minor element geochemistry of Neocomian (Lower Cretaceous) pelagic carbonates of the North Atlantic Basin (Deep Sea Drilling Project Sites 105, 367, 387, 391, and 603) was examined to develop a diagenetic model for pelagic limestones. In particular, we hoped to test the fidelity of whole-rock geochemical records as paleoceanographic indicators for pelagic deposits of pre-Aptian age, in which individual microfossils are not available for analysis. Data indicate that in addition to depth of burial, rhythmic variations in primary carbonate content have strongly controlled diagenetic patterns and associated geochemical signatures in these Neocomian sequences. Samples become increasingly depleted in Sr and 18O with increasing CaCO3 content. Within individual sedimentary sections, substantial decreases in Sr/Ca ratios and δ18O values are evident over a range of 4 to 98% CaCO3. However, even over a relatively narrow range of 50 to 98% CaCO3 a 2.5‰ variation in δ18O values and a change of a factor of 1.7 in Sr/Ca ratios are observed. Carbon isotope compositions do not vary as extensively with CaCO3 content, but carbonate- rich intervals tend to be relatively depleted in 13C. Petrographic analysis reveals that these geochemical patterns are related to the transfer of CaCO3 from carbonate- poor intervals (calcareous shales and marlstones) to adjacent carbonate-rich intervals (limestones) during burial compaction and pressure solution. This process results in the addition of diagenetic cement to carbonaterich intervals to produce a bulk composition that is relatively depleted in Sr and 18O and, at the same time, enables the retention of more-or-less primary carbonate that is relatively enriched in Sr and 18O in adjacent carbonate- poor intervals. Thus, although cyclic variations in CaCO3 content are primary in the Neocomian sequences examined, measured variations in Sr/Ca ratios and δ18O values are not and, as such, do not provide reliable proxies for past variations in climate, oceanographic conditions, or global ice volume

    Field Test Performance of Junior Competitive Surf Athletes following a Core Strength Training Program

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    International Journal of Exercise Science 11(6): 696-707, 2018. Lower body and core muscular strength are essential for optimal performance in many sports and competitive surfers have similar strength demands when maneuvering a surfboard to achieve competition success. Presently, the use of unstable surfaces is excessively utilized by surf coaches and trainers and to date, research does not support this as an effective training method for long-term improvements. Therefore, the purpose of this study was to determine the effectiveness of an 8-week Core Strength Training Program (CSTP) on a battery of field tests specific to assessing core musculature and lower body strength for junior competitive surf athletes. Nineteen American junior competitive surf athletes (age:15.7±1.01yrs, height:1.77±0.007m, mass:64.67±9.08kg) completed pre- and post-tests with a transitional pre-season to in-season 8-week CSTP intervention. The battery of tests included: rotational power (RP), time to peak acceleration (TP), maximal acceleration (Ma), maximal countermovement jump (CMJ), estimated peak power (PP), core strength (CS), core endurance (CE), and rotational flexibility (RF). Means, standard deviations, RMANOVA with a significance level of p \u3c 0.05, and effect sizes were computed. Results demonstrated significant improvements in L.RP, TP, CMJ, PP, CS, and RF. Based on the results, the CSTP is an effective training program for surf coaches and strength and conditioning professionals to improve strength in the core musculature and lower body. In addition, we conclude implementation of the CSTP enhances athletic performance measurements which will likely increase competition success

    Non-intersecting Brownian walkers and Yang-Mills theory on the sphere

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    We study a system of N non-intersecting Brownian motions on a line segment [0,L] with periodic, absorbing and reflecting boundary conditions. We show that the normalized reunion probabilities of these Brownian motions in the three models can be mapped to the partition function of two-dimensional continuum Yang-Mills theory on a sphere respectively with gauge groups U(N), Sp(2N) and SO(2N). Consequently, we show that in each of these Brownian motion models, as one varies the system size L, a third order phase transition occurs at a critical value L=L_c(N)\sim \sqrt{N} in the large N limit. Close to the critical point, the reunion probability, properly centered and scaled, is identical to the Tracy-Widom distribution describing the probability distribution of the largest eigenvalue of a random matrix. For the periodic case we obtain the Tracy-Widom distribution corresponding to the GUE random matrices, while for the absorbing and reflecting cases we get the Tracy-Widom distribution corresponding to GOE random matrices. In the absorbing case, the reunion probability is also identified as the maximal height of N non-intersecting Brownian excursions ("watermelons" with a wall) whose distribution in the asymptotic scaling limit is then described by GOE Tracy-Widom law. In addition, large deviation formulas for the maximum height are also computed.Comment: 37 pages, 4 figures, revised and published version. A typo has been corrected in Eq. (10

    The Variable Stars and Blue Horizontal Branch of the Metal-Rich Globular Cluster NGC 6441

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    We present time-series VI photometry of the metal-rich ([Fe/H] = -0.53) globular cluster NGC 6441. Our color-magnitude diagram shows that the extended blue horizontal branch seen in Hubble Space Telescope data exists in the outermost reaches of the cluster. The red clump slopes nearly parallel to the reddening vector. A component of this slope is due to differential reddening, but part is intrinsic. The blue horizontal branch stars are more centrally concentrated than the red clump stars. We have discovered about 50 new variable stars near NGC 6441, among them eight or more RR Lyrae stars which are very probably cluster members. Comprehensive period searches over the range 0.2-1.0 days yielded unusually long periods (0.5-0.9 days) for the fundamental pulsators compared with field RR Lyrae of the same metallicity. Three similar long-period RR Lyrae are known in other metal-rich globulars. With over ten examples in hand, it seems that a distinct sub-class of RR Lyrae is emerging. The observed properties of the horizontal branch stars are in reasonable agreement with recent models which invoke deep mixing to enhance the atmospheric helium abundance, while they conflict with models which assume high initial helium abundance. The light curves of the c-type RR Lyrae seem to have unusually long rise times and sharp minima. Reproducing these light curves in stellar pulsation models may provide another means of constraining the physical variables responsible for the anomalous blue horizontal branch extension and sloped red clump observed in NGC 6441.Comment: 30 pages plus 6 EPS and 6 JPEG figures; uses AAS TeX. Accepted by the Astronomical Journal. Minor changes include computing He abundance, modifications to Figs 1 and 8, and expansion on idea that blue HB stars may be produced in binarie

    The mean field theory of spin glasses: the heuristic replica approach and recent rigorous results

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    The mathematically correct computation of the spin glasses free energy in the infinite range limit crowns 25 years of mathematic efforts in solving this model. The exact solution of the model was found many years ago by using a heuristic approach; the results coming from the heuristic approach were crucial in deriving the mathematical results. The mathematical tools used in the rigorous approach are quite different from those of the heuristic approach. In this note we will review the heuristic approach to spin glasses in the light of the rigorous results; we will also discuss some conjectures that may be useful to derive the solution of the model in an alternative way.Comment: 12 pages, 1 figure; lecture at the Flato Colloquia Day, Thursday 27 November, 200
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