1,235 research outputs found

    THE EFFECT OF CONDTIONAL DISCRIMINATION TRAINING ON CHOICE MAKING IN CHILDREN DURING `PRE-GAMBLING\u27 ACTIVITIES

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    Past research has shown conditional discrimination training of a stimulus to change its function by manipulating variables within the contingencies (e.g., Johnson & Dixon, 2009), and the present study attempted to extend this research. Experimenters exposed 3 children (ages 6-9 years) to a computer program that trained participant to discriminate between two contextual cures (blue and yellow) representing more than and less than. All three participants will demonstrate an increased preference toward the color that had been paired with more than during both conditional discrimination training phases

    Efficiency of initiating cell adhesion in hydrodynamic flow

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    We theoretically investigate the efficiency of initial binding between a receptor-coated sphere and a ligand-coated wall in linear shear flow. The mean first passage time for binding decreases monotonically with increasing shear rate. Above a saturation threshold of the order of a few 100 receptor patches, the binding efficiency is enhanced only weakly by increasing their number and size, but strongly by increasing their height. This explains why white blood cells in the blood flow adhere through receptor patches localized to the tips of microvilli, and why malaria-infected red blood cells form elevated receptor patches (knobs).Comment: 4 pages, Revtex, 4 Postscript figures included, to appear in PR

    On sets of irreducible polynomials closed by composition

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    Let S\mathcal S be a set of monic degree 22 polynomials over a finite field and let CC be the compositional semigroup generated by S\mathcal S. In this paper we establish a necessary and sufficient condition for CC to be consisting entirely of irreducible polynomials. The condition we deduce depends on the finite data encoded in a certain graph uniquely determined by the generating set S\mathcal S. Using this machinery we are able both to show examples of semigroups of irreducible polynomials generated by two degree 22 polynomials and to give some non-existence results for some of these sets in infinitely many prime fields satisfying certain arithmetic conditions

    Signing on a Postcard

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    We investigate the problem of signing short messages using a scheme that minimizes the total length of the original message and the appended signature. This line of research was motivated by several postal services interested by stamping machines capable of producing digital signatures. Although several message recovery schemes exist, their security is questionable. This paper proposes variants of DSA and ECDSA allowing partial recovery: the signature is appended to a truncated message and the discarded bytes are recovered by the verification algorithm

    Evaluating the Effect of Crutch-using on Trunk Muscle Loads

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    As a traditional tool of external assistance, crutches play an important role in society. They have a wide range of applications to help either the elderly and disabled to walk or to treat certain illnesses or for post-operative rehabilitation. But there are many different types of crutches, including shoulder crutches and elbow crutches. How to choose has become an issue that deserves to be debated. Because while crutches help people walk, they also have an impact on the body. Inappropriate choice of crutches or long-term misuse can lead to problems such as scoliosis. Previous studies were mainly experimental measurements or the construction of dynamic models to calculate the load on joints with crutches. These studies focus only on the level of the joints, ignoring the role that muscles play in this process. Although some also take into account the degree of muscle activation, there is still a lack of quantitative analysis. The traditional dynamic model can be used to calculate the load on each joint. However, due to the activation of the muscle, this situation only causes part of the load transmitted to the joint, and the work of the chair will compensate the other part of the load. Analysis at the muscle level allows a better understanding of the impact of crutches on the body. By comparing the levels of activation of the trunk muscles, it was found that the use of crutches for walking, especially a single crutch, can cause a large difference in the activation of the back muscles on the left and right sides, and this difference will cause muscle degeneration for a long time, leading to scoliosis. In this article taking scoliosis as an example, by analyzing the muscles around the spine, we can better understand the pathology and can better prevent diseases. The objective of this article is to analyze normal walking compared to walking with one or two crutches using OpenSim software to obtain the degree of activation of different muscles in order to analyze the impact of crutches on the body

    L-selectin mediated leukocyte tethering in shear flow is controlled by multiple contacts and cytoskeletal anchorage facilitating fast rebinding events

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    L-selectin mediated tethers result in leukocyte rolling only above a threshold in shear. Here we present biophysical modeling based on recently published data from flow chamber experiments (Dwir et al., J. Cell Biol. 163: 649-659, 2003) which supports the interpretation that L-selectin mediated tethers below the shear threshold correspond to single L-selectin carbohydrate bonds dissociating on the time scale of milliseconds, whereas L-selectin mediated tethers above the shear threshold are stabilized by multiple bonds and fast rebinding of broken bonds, resulting in tether lifetimes on the timescale of 10110^{-1} seconds. Our calculations for cluster dissociation suggest that the single molecule rebinding rate is of the order of 10410^4 Hz. A similar estimate results if increased tether dissociation for tail-truncated L-selectin mutants above the shear threshold is modeled as diffusive escape of single receptors from the rebinding region due to increased mobility. Using computer simulations, we show that our model yields first order dissociation kinetics and exponential dependence of tether dissociation rates on shear stress. Our results suggest that multiple contacts, cytoskeletal anchorage of L-selectin and local rebinding of ligand play important roles in L-selectin tether stabilization and progression of tethers into persistent rolling on endothelial surfaces.Comment: 9 pages, Revtex, 4 Postscript figures include

    A faster pseudo-primality test

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    We propose a pseudo-primality test using cyclic extensions of Z/nZ\mathbb Z/n \mathbb Z. For every positive integer klognk \leq \log n, this test achieves the security of kk Miller-Rabin tests at the cost of k1/2+o(1)k^{1/2+o(1)} Miller-Rabin tests.Comment: Published in Rendiconti del Circolo Matematico di Palermo Journal, Springe
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