4,877 research outputs found

    Applying Math onto Mechanism: Investigating the Relationship Between Mechanistic and Mathematical Understanding

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    Physical manipulatives are commonly used to improve mathematical understanding. However, it is unclear when physical manipulatives lead to significant benefits. We investigated whether understanding the mechanism of a manipulative would affect mathematical use and understanding. Participants were asked to navigate a physical robot through a maze, and to create a strategy that could navigate differently sized robots through the same maze. Participants with a better understanding of the robot’s mechanism were more likely to utilize complex mathematical strategies during the maze task than participants with lower mechanistic understanding. These participants with higher mechanistic understanding also showed greater understanding of the mathematical relationships within the robot. The study provides evidence for a relationship between mechanistic understanding and mathematical understanding, suggesting that mechanistic manipulatives, upon which mathematics can be applied, may be especially beneficial for fostering mathematical understanding

    Health behavior modification after electron beam computed tomography and physician consultation

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    This study aimed to determine whether participants reported altering health behaviors (physical activity, diet, and alcohol consumption) after seeing results from an electron-beam computed tomography (EBCT) scan for coronary artery calcium and reviewing these results with a physician. Clinicians attempt to motivate patients to control cardiovascular risk factors by adopting healthy behaviors and reducing harmful actions. Asymptomatic patients (N = 510) were evaluated by EBCT for the extent of coronary artery calcium. Information pertaining to demographics, health history, and lifestyle/health behaviors was obtained from each participant at the time of the EBCT scan. Patients were given their numerical calcium score, shown images of their coronary arteries, and counseled by a physician for lifestyle and medical risk modification based on their coronary artery calcium score. Approximately 6 years after the scan, participants completed a follow-up questionnaire related to lifestyle modifications. In multivariable analysis, the presence and extent of coronary artery calcium was significantly associated with beneficial health behavior modifications. Specifically, the greater a patient’s coronary artery calcium score, the more likely they were to report increasing exercise (odds ratio = 1.34, P = 0.02), changing diet (odds ratio = 1.40, P < 0.01), and changing alcohol intake (odds ratio = 1.46, P = 0.05). This study suggests that seeing and being counseled on the presence and extent of coronary artery calcium is significantly associated with behavior change

    From UV to NIR: A Full-Spectrum Metal-Free Photocatalyst for Efficient Polymer Synthesis in Aqueous Conditions

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    Photo‐mediation offers unparalleled spatiotemporal control over controlled radical polymerizations (CRP). Photo‐induced electron/energy transfer reversible addition–fragmentation chain transfer (PET‐RAFT) polymerization is particularly versatile owing to its oxygen tolerance and wide range of compatible photocatalysts. In recent years, broadband‐ and near‐infrared (NIR)‐mediated polymerizations have been of particular interest owing to their potential for solar‐driven chemistry and biomedical applications. In this work, we present the first example of a novel photocatalyst for both full broadband‐ and NIR‐mediated CRP in aqueous conditions. Well‐defined polymers were synthesized in water under blue, green, red, and NIR light irradiation. Exploiting the oxygen tolerant and aqueous nature of our system, we also report PET‐RAFT polymerization at the microliter scale in a mammalian cell culture medium

    Recommending software features to designers: From the perspective of users

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    With lots of public software descriptions emerging in the application market, it is significant to extract common software features from these descriptions and recommend them to new designers. However, existing approaches often recommend features according to their frequencies which reflect designers’ preferences. In order to identify those users’ favorite features and help design more popular software, this paper proposes to make use of the public data of users’ ratings and products’ downloads which reflect users’ preferences to recommend extracted features. The proposed approach distinguishes users’ perspective from designers’ perspective and argues that users’ perspective is better for recommending features because most products are designed for users and expect to be popular among users. Based on the lasso regression to estimate the relationship between the extracted features and the users’ ratings, it proposes to first distinguish the extracted features to identify those rec- ommendable and undesirable features. By treating each download as a support from users to the product features, it further mines the feature association rules from users’ perspective for recommending features. By taking the public data on the market of SoftPedia.com for evaluation, our empirical studies indicate that: (1) selecting recommendable features by lasso regression is better than that by feature frequencies in terms of F1 measure; and (2) recommending features based on the feature association rules mined from users’ perspective is not only feasible but also has competitive performance compared with that based on the rules mined from designs’ perspective in terms of F1 measure

    Possible Effects of Quantum Mechanics Violation Induced by Certain Quantum Gravity on Neutrino Oscillations

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    In this work we tried extensively to apply the EHNS postulation about the quantum mechanics violation effects induced by the quantum gravity of black holes to neutrino oscillations. The possibilities for observing such effects in the neutrino experiments (in progress and/or accessible in the near future) were discussed. Of them, an interesting one was outlined specially.Comment: 18 pages, 0 figure, (1 REVTeX file

    Socioeconomic status in childhood and C reactive protein in adulthood: a systematic review and meta-analysis

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    Inflammation plays a central role in cardio-metabolic disease and may represent a mechanism linking low socioeconomic status (SES) in early life and adverse cardio-metabolic health outcomes in later life. Accumulating evidence suggests an association between childhood SES and adult inflammation, but findings have been inconsistent

    Receiver Function Constraints on Crustal Seismic Velocities and Partial Melting beneath the Red Sea Rift and Adjacent Regions, Afar Depression

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    The Afar Depression is an ideal locale for the investigation of crustal processes involved in the transition from continental rifting to oceanic spreading. To provide relatively high resolution images of the crust beneath the Red Sea rift (RSR) represented by the Tendaho graben in the Afar Depression, we deployed an array of 18 broadband seismic stations in 2010 and 2011. Stacking of about 2300 receiver functions from the 18 and several nearby stations along the ~200 km long array reveals an average crustal thickness of 22 ± 4 km, ranging from ~17 km near the RSR axis to 30 km within the overlap zone between the Red Sea and Gulf of Aden rifts. The resulting anomalously high Vp/Vs ratios decrease from 2.40 in the southwest to 1.85 within the overlap zone. We utilize theoretical Vp and melt fraction relationships to obtain an overall highly reduced average crustal Vp of ~5.1 km/s. The melt percentage is about 10% beneath the RSR while the overlap zone contains minor quantities of partial melt. The observed high Vp/Vs values beneath most of the study area indicate widespread partial melting beneath the southwest half of the profile, probably as a result of gradual eastward migration of the RSR axis. Our results also suggest that the current extensional strain in the lower crust beneath the region is diffuse, while the strain field in the upper crust is localized along narrow volcanic segments. These disparate styles of deformation imply a high degree of decoupling between the upper and lower crust

    Noncyclic geometric phase for neutrino oscillation

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    We provide explicit formulae for the noncyclic geometric phases or Pancharatnam phases of neutrino oscillations. Since Pancharatnam phase is a generalization of the Berry phase, our results generalize the previous findings for Berry phase in a recent paper [Phys. Lett. B, 466 (1999) 262]. Unlike the Berry phase, the noncyclic geometric phase offers distinctive advantage in terms of measurement and prediction. In particular, for three-flavor mixing, our explicit formula offers an alternative means of determining the CP-violating phase. Our results can also be extended easily to explore geometric phase associated with neutron-antineutron oscillations

    General Approach for Combining Diverse Rare Variant Association Tests Provides Improved Robustness Across a Wider Range of Genetic Architectures

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    The widespread availability of genome sequencing data made possible by way of next-generation technologies has yielded a flood of different gene-based rare variant association tests. Most of these tests have been published because they have superior power for particular genetic architectures. However, for applied researchers it is challenging to know which test to choose in practice when little is known a priori about genetic architecture. Recently, tests have been proposed which combine two particular individual tests (one burden and one variance components) to minimize power loss while improving robustness to a wider range of genetic architectures. In our analysis we propose an expansion of these approaches, yielding a general method that works for combining any number of individual tests. We demonstrate that running multiple different tests on the same dataset and using a Bonferroni correction for multiple testing is never better than combining tests using our general method. We also find that using a test statistic that is highly robust to the inclusion of non-causal variants (Joint-infinity) together with a previously published combined test (SKAT-O) provides improved robustness to a wide range of genetic architectures and should be considered for use in practice. Software for this approach is supplied. We support the increased use of combined tests in practice-- as well as further exploration of novel combined testing approaches using the general framework provided here--to maximize robustness of rare-variant testing strategies against a wide range of genetic architectures

    Four--Neutrino Oscillation Solutions of the Solar Neutrino Problem

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    We present an analysis of the neutrino oscillation solutions of the solar neutrino problem in the framework of four-neutrino mixing where a sterile neutrino is added to the three standard ones. We perform a fit to the full data set corresponding to the 825-day Super-Kamiokande data sample as well as to Chlorine, GALLEX and SAGE and Kamiokande experiments. In our analysis we use all measured total event rates as well as all Super-Kamiokande data on the zenith angle dependence and the recoil electron energy spectrum. We consider both transitions via the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism as well as oscillations in vacuum (just-so) and find the allowed solutions for different values of the additional mixing angles. This framework permits transitions into active or sterile neutrinos controlled by the additional parameter cos2(ϑ23)cos2(ϑ24)\cos^2(\vartheta_{23}) \cos^2(\vartheta_{24}) . We discuss the maximum allowed values of this additional mixing parameter for the different solutions.Comment: 28 pages Latex file using RevTeX. 8 postscript figures included (bitmapped for compression). Detailed explanation of criterion 3 and lower two graphs of Fig. 8. Misprints corrected in table II.A full version of the paper can be found at http://ific.uv.es/~penya/papers/four
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