50,855 research outputs found

    Inference of internal stress in a cell monolayer

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    We combine traction force data with Bayesian inversion to obtain an absolute estimate of the internal stress field of a cell monolayer. The method, Bayesian inversion stress microscopy (BISM), is validated using numerical simulations performed in a wide range of conditions. It is robust to changes in each ingredient of the underlying statistical model. Importantly, its accuracy does not depend on the rheology of the tissue. We apply BISM to experimental traction force data measured in a narrow ring of cohesive epithelial cells, and check that the inferred stress field coincides with that obtained by direct spatial integration of the traction force data in this quasi-one-dimensional geometry.Comment: 38 pages, 14 figure

    Rotating Electromagnetic Waves in Toroid-Shaped Regions

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    Electromagnetic waves, solving the full set of Maxwell equations in vacuum, are numerically computed. These waves occupy a fixed bounded region of the three dimensional space, topologically equivalent to a toroid. Thus, their fluid dynamics analogs are vortex rings. An analysis of the shape of the sections of the rings, depending on the angular speed of rotation and the major diameter, is carried out. Successively, spherical electromagnetic vortex rings of Hill's type are taken into consideration. For some interesting peculiar configurations, explicit numerical solutions are exhibited.Comment: 27 pages, 40 figure

    Free Form Lensing Implications for the Collision of Dark Matter and Gas in the Frontier Fields Cluster MACSJ0416.1-2403

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    We present a free form mass reconstruction of the massive lensing cluster MACSJ0416.1-2403 using the latest Hubble Frontier Fields data. Our model independent method finds that the extended lensing pattern is generated by two elongated, closely projected clusters of similar mass. Our lens model identifies new lensed images with which we improve the accuracy of the dark matter distribution. We find that the bimodal mass distribution is nearly coincident with the bimodal X-ray emission, but with the two dark matter peaks lying closer together than the centroids of the X-ray emisison. We show this can be achieved if the collision has occurred close to the plane and such that the cores are deflected around each other. The projected mass profiles of both clusters are well constrained because of the many interior lensed images, leading to surprisingly flat mass profiles of both components in the region 15-100 kpc. We discuss the extent to which this may be generated by tidal forces in our dynamical model which are large during an encounter of this type as the cores "graze" each other. The relative velocity between the two cores is estimated to be about 1200 km/s and mostly along the line of sight so that our model is consistent with the relative redshift difference between the two cD galaxies (dz = 0.04).Comment: 22 pages, 18 figures, 2 table

    Study of large adaptive arrays for space technology applications

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    The research in large adaptive antenna arrays for space technology applications is reported. Specifically two tasks were considered. The first was a system design study for accurate determination of the positions and the frequencies of sources radiating from the earth's surface that could be used for the rapid location of people or vehicles in distress. This system design study led to a nonrigid array about 8 km in size with means for locating the array element positions, receiving signals from the earth and determining the source locations and frequencies of the transmitting sources. It is concluded that this system design is feasible, and satisfies the desired objectives. The second task was an experiment to determine the largest earthbound array which could simulate a spaceborne experiment. It was determined that an 800 ft array would perform indistinguishably in both locations and it is estimated that one several times larger also would serve satisfactorily. In addition the power density spectrum of the phase difference fluctuations across a large array was measured. It was found that the spectrum falls off approximately as f to the minus 5/2 power

    In Search of the Right Trousers Pattern - Comparison of Four Different Pattern Making Methods in Affordance with Different Body Shapes

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    Clothing comfort is one of the major concerns in the clothing industry. Various pattern making methods have been introduced to the industry with consideration to clothing comfort. This study evaluates four pattern making methods known as the ESMOD, Bunka, Aldrich, and Armstrong methods. The work focuses on trouser patterns and uses two subjects who have similar height, weight and BMI but have different body shapes and body sizes. The body measurement data of the two subjects were collected using a three-dimensional body scanner and patterns of the four different methods were developed accordingly. The fit of experimental garments were examined by two subjects and experts using questionnaires and were analysed

    Possible Excess in Charged Current Events with High-Q^2 at HERA from Stop and Sbottom Production

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    We investigate a production process e^+p \to \st X \to \sb W^+ X at HERA, where we consider a decay mode \sb \to \bar{\nu}_e d of the sbottom in the framework of an R-parity breaking supersymmetric standard model. Both processes of the stop production e^+ d \to \st and the sbottom decay \sb \to \bar{\nu}_e d are originated from an R-parity breaking superpotential λ131L^1Q^3Dc^1\lambda'_{131} \hat{L}_1 \hat{Q}_3 \hat{D^c}_1. One of signatures of the process should be a large missing transverse momentum plus multijet events corresponding to hadronic decays of the WW. It is shown that the signal could appear as an event excess in the charged current (CC) processes e+pνXe^+p \to \nu X with the high Q2Q^2 at HERA. We compare expected event distributions with the CC data recently reported by the H1 and ZEUS groups at HERA. Methods for extracting the signal from the standard CC processes are also discussed.Comment: 13 pages, LaTeX, 3 figure
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