WorldWideScience

Sample records for scattering response function

  1. Modeling the scatter response function in inhomogeneous scattering media for SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Frey, E.C.; Tsui, B.M.W. (Univ. of North Carolina, Chapel Hill, NC (United States))

    1994-08-01

    The authors previously developed a method for accurately and rapidly modeling the scatter response function in uniform media. In this work the authors studied the extension of this method to nonuniform attenuators. The authors approach was to use the water-equivalent source depth. The authors have investigated the accuracy of three different methods based on this approximation using Monte Carlo (MC) simulation methods. Line sources were placed at the same water equivalent depth in slabs composed of water, bone, and lung. The authors observed that, for perfect collimation, the scatter response functions (SRFs) obtained for these slabs are comparable. To determine whether attenuation coefficients alone are sufficient to estimate the SRF or whether one must know the elemental composition, the authors simulated SRFs for sources in bone and lung as well as bone- and lung-equivalent materials. The bone- and lung-equivalent materials have the same attenuation coefficient as bone and lung, respectively, but the same elemental composition as water. For the lung-equivalent material, the SRFs were essentially equivalent to those from lung; for the bone-equivalent material, the SRFs were closer to those from water. The authors have also placed voids of various sizes in slab phantoms while keeping the same water-equivalent source depth. For these simple geometries two of the methods based on the effective depth were adequate for predicting the SRF. Finally, the authors have simulated the SRF for a line source in a realistic thorax phantom using several methods based on geometric and water-equivalent distances. The results indicate that one of the methods gives reasonably good agreement with direct MC simulations in terms of predicting the magnitude and shape of the SRFs and projection data for a complex distribution simulating the heart. This method was not the same as the one that gave good agreement in the case of the simpler phantoms.

  2. Longitudinal response functions for quasielastic electron scattering in relativistic non-linear models

    CERN Document Server

    Caillon, J C

    2002-01-01

    The longitudinal response functions for quasielastic electron scattering on sup 1 sup 2 C, sup 4 sup 0 Ca and sup 5 sup 6 Fe have been calculated in relativistic non-linear models taking into account RPA correlations. For these calculations, a covariant, consistent, calculation of the nuclear matter linear response has been performed. The effect of the non-linear terms on the longitudinal response has been discussed.

  3. Scattering functions of Platonic solids

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin [Rensselaer Polytechnic Institute; Shew, Chwen-Yang [City University of New York (CUNY); He, Lilin [ORNL; Meilleur, Flora [ORNL; Myles, Dean A A [ORNL; Liu, Emily [Rensselaer Polytechnic Institute; Zhang, Yang [ORNL; Smith, Greg [ORNL; Herwig, Kenneth W [ORNL; Pynn, Roger [ORNL; Chen, Wei-Ren [ORNL

    2011-01-01

    The single-particle small-angle scattering properties of five Platonic solids, including the tetrahedron, hexahedron, octahedron, dodecahedron and icosahedron, are systematically investigated. For each given geometry, the Debye spatial autocorrelation function, pair distance distribution function and intraparticle structure factor (form factor) are calculated and compared with the corresponding scattering function of a spherical reference system. From the theoretical models, the empirical relationship between the dodecahedral and icosahedral structural characteristics and those of the equivalent spheres is found. Moreover, the single-particle scattering properties of icosahedral and spherical shells with identical volume are investigated, and the prospect of using different data analysis approaches to explore their structural differences is presented and discussed.

  4. Scattering functions of Platonic solids

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Ren [ORNL; Herwig, Kenneth W [ORNL; Li, Xin [ORNL; Liu, Emily [Rensselaer Polytechnic Institute (RPI); Pynn, Roger [ORNL; Shew, Chwen-Yang [City University of New York (CUNY); Smith, Gregory Scott [ORNL; Myles, Dean A A [ORNL; He, Lilin [ORNL; Meilleur, Flora [ORNL

    2011-01-01

    In this report the single-particle scattering properties of five Platonic solids, including tetrahedron, hexahedron, octahedron, dodecahedron and icosahedron, are investigated in a systematic manner. For each given geometry, the Debye spatial autocorrelation function (r), pair distance distribution function (PDDF) p (r) and intraparticle structure factor (form factor) P (Q) are respectively calculated and compared to the corresponding scattering function of the spherical referential system. Based on our theoretical models, the empirical relationship between the dodecahedral and icosahedral structural characteristics and those of the equivalent spheres is found. Moreover, the single-particle scattering properties of the icosahedral and the spherical shells with the same volume are further investigated and the prospect of using different data analysis approaches to explore their structural difference is also presented and discussed.

  5. Calculating scattering matrices by wave function matching

    Energy Technology Data Exchange (ETDEWEB)

    Zwierzycki, M. [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznan (Poland); Khomyakov, P.A.; Starikov, A.A.; Talanana, M.; Xu, P.X.; Karpan, V.M.; Marushchenko, I.; Brocks, G.; Kelly, P.J. [Faculty of Science and Technology and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Xia, K. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Turek, I. [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, 616 62 Brno (Czech Republic); Bauer, G.E.W. [Kavli Institute of NanoScience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands)

    2008-04-15

    The conductance of nanoscale structures can be conveniently related to their scattering properties expressed in terms of transmission and reflection coefficients. Wave function matching (WFM) is a transparent technique for calculating transmission and reflection matrices for any Hamiltonian that can be represented in tight-binding form. A first-principles Kohn-Sham Hamiltonian represented on a localized orbital basis or on a real space grid has such a form. WFM is based upon direct matching of the scattering-region wave function to the Bloch modes of ideal leads used to probe the scattering region. The purpose of this paper is to give a pedagogical introduction to WFM and present some illustrative examples of its use in practice. We briefly discuss WFM for calculating the conductance of atomic wires, using a real space grid implementation. A tight-binding muffin-tin orbital implementation very suitable for studying spin-dependent transport in layered magnetic materials is illustrated by looking at spin-dependent transmission through ideal and disordered interfaces. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Probability density functions of instantaneous Stokes parameters on weak scattering

    Science.gov (United States)

    Chen, Xi; Korotkova, Olga

    2017-10-01

    The single-point probability density functions (PDF) of the instantaneous Stokes parameters of a polarized plane-wave light field scattered from a three-dimensional, statistically stationary, weak medium with Gaussian statistics and Gaussian correlation function have been studied for the first time. Apart from the scattering geometry the PDF distributions of the scattered light have been related to the illumination's polarization state and the correlation properties of the medium.

  7. Applying Loop-Flower Basis Functions to Analyze Electromagnetic Scattering Problems of PEC Scatterers

    Directory of Open Access Journals (Sweden)

    Gaobiao Xiao

    2014-01-01

    Full Text Available This paper discusses the application of loop-flower basis functions for solving surface integral equations involved in electromagnetic scattering problems on perfectly electrically conducting surfaces. Flower-shaped basis functions are proposed to replace the conventional star basis functions. The flower basis functions are defined based on mesh nodes instead of surface triangles. It is shown that the loop-flower basis functions not only can be used to handle the electromagnetic scattering problems at very low frequencies, but also can be directly used to implement Calderon preconditioners for EFIEs.

  8. Representation theorems and Green's function retrieval for scattering in acoustic media.

    Science.gov (United States)

    Vasconcelos, Ivan; Snieder, Roel; Douma, Huub

    2009-09-01

    Reciprocity theorems for perturbed acoustic media are provided in the form of convolution- and correlation-type theorems. These reciprocity relations are particularly useful in the general treatment of both forward and inverse-scattering problems. Using Green's functions to describe perturbed and unperturbed waves in two distinct wave states, representation theorems for scattered waves are derived from the reciprocity relations. While the convolution-type theorems can be manipulated to obtain scattering integrals that are analogous to the Lippmann-Schwinger equation, the correlation-type theorems can be used to retrieve the scattering response of the medium by cross correlations. Unlike previous formulations of Green's function retrieval, the extraction of scattered-wave responses by cross correlations does not require energy equipartitioning. Allowing for uneven energy radiation brings experimental advantages to the retrieval of fields scattered by remote lossless and/or attenuative scatterers. These concepts are illustrated with a number of examples, including analytic solutions to a one-dimensional scattering problem, and a numerical example in the context of seismic waves recorded on the ocean bottom.

  9. Two-dimensional analytic weighting functions for limb scattering

    Science.gov (United States)

    Zawada, D. J.; Bourassa, A. E.; Degenstein, D. A.

    2017-10-01

    Through the inversion of limb scatter measurements it is possible to obtain vertical profiles of trace species in the atmosphere. Many of these inversion methods require what is often referred to as weighting functions, or derivatives of the radiance with respect to concentrations of trace species in the atmosphere. Several radiative transfer models have implemented analytic methods to calculate weighting functions, alleviating the computational burden of traditional numerical perturbation methods. Here we describe the implementation of analytic two-dimensional weighting functions, where derivatives are calculated relative to atmospheric constituents in a two-dimensional grid of altitude and angle along the line of sight direction, in the SASKTRAN-HR radiative transfer model. Two-dimensional weighting functions are required for two-dimensional inversions of limb scatter measurements. Examples are presented where the analytic two-dimensional weighting functions are calculated with an underlying one-dimensional atmosphere. It is shown that the analytic weighting functions are more accurate than ones calculated with a single scatter approximation, and are orders of magnitude faster than a typical perturbation method. Evidence is presented that weighting functions for stratospheric aerosols calculated under a single scatter approximation may not be suitable for use in retrieval algorithms under solar backscatter conditions.

  10. Space race functional responses.

    Science.gov (United States)

    Sjödin, Henrik; Brännström, Åke; Englund, Göran

    2015-02-22

    We derive functional responses under the assumption that predators and prey are engaged in a space race in which prey avoid patches with many predators and predators avoid patches with few or no prey. The resulting functional response models have a simple structure and include functions describing how the emigration of prey and predators depend on interspecific densities. As such, they provide a link between dispersal behaviours and community dynamics. The derived functional response is general but is here modelled in accordance with empirically documented emigration responses. We find that the prey emigration response to predators has stabilizing effects similar to that of the DeAngelis-Beddington functional response, and that the predator emigration response to prey has destabilizing effects similar to that of the Holling type II response. A stability criterion describing the net effect of the two emigration responses on a Lotka-Volterra predator-prey system is presented. The winner of the space race (i.e. whether predators or prey are favoured) is determined by the relationship between the slopes of the species' emigration responses. It is predicted that predators win the space race in poor habitats, where predator and prey densities are low, and that prey are more successful in richer habitats. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  11. A new phantom for fast determination of the scatter response of a gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Beekman, F.J.; Frey, E.C.; Kamphuis, C.; Tsui, B.M.W.; Viergever, M.A. (Univ. of North Carolina, Chapel Hill, NC (United States))

    1994-08-01

    A triangular phantom is proposed which enables the determination and parameterization of the depth dependent scatter response function (SRF) in uniformly attenuating objects for Single Photon Emission Computed Tomography (SPECT) by means of a single line source measurement. This approach replaces a tedious measurement series with line sources at various depths in slab phantoms. The method is evaluated for [sup 99m]Tc. Monte Carlo simulations of SRFs and scatter-to-primary ratios (SPRs) of the triangular phantom are compared with those of slabs. It is found that both the SPRs and the shapes of the SRFs from the slab and triangular phantoms are in excellent agreement. In addition, the data obtained from a single measurement using the triangular phantom can be used in the parameterization of the slab phantom SRF and can be described by an analytical expression of the line source response function. This information can be combined with knowledge of the geometric detector response and the shape of the object to compute the full scatter response function in convex shaped objects. This method for estimating scatter can serve as the basis for accurate scatter compensation in SPECT.

  12. GADRAS Detector Response Function.

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Dean J.; Harding, Lee; Thoreson, Gregory G; Horne, Steven M.

    2014-11-01

    The Gamma Detector Response and Analysis Software (GADRAS) applies a Detector Response Function (DRF) to compute the output of gamma-ray and neutron detectors when they are exposed to radiation sources. The DRF is fundamental to the ability to perform forward calculations (i.e., computation of the response of a detector to a known source), as well as the ability to analyze spectra to deduce the types and quantities of radioactive material to which the detectors are exposed. This document describes how gamma-ray spectra are computed and the significance of response function parameters that define characteristics of particular detectors.

  13. Space race functional responses

    National Research Council Canada - National Science Library

    Sjödin, Henrik; Brännström, Åke; Englund, Göran

    2015-01-01

    We derive functional responses under the assumption that predators and prey are engaged in a space race in which prey avoid patches with many predators and predators avoid patches with few or no prey...

  14. Phase-function method for Coulomb-distorted nuclear scattering

    Energy Technology Data Exchange (ETDEWEB)

    Sett, G.C.; Laha, U.; Talukdar, B.

    1988-09-21

    The phase-function method is very effective in treating quantum mechanical scattering problems for short-range local potentials. We adapt the phase method to deal with Coulomb plus Graz non-local separable potentials and derive a closed-form expression for the scattering phase shift. Our approach to the problem circumvents in a rather natural way the typical difficulties of incorporating the Coulomb interaction in a nuclear phase-shift calculation. We demonstrate the usefulness of our constructed expression by means of a model calculation.

  15. Intermediate scattering function of an anisotropic active Brownian particle

    Science.gov (United States)

    Kurzthaler, Christina; Leitmann, Sebastian; Franosch, Thomas

    2016-10-01

    Various challenges are faced when animalcules such as bacteria, protozoa, algae, or sperms move autonomously in aqueous media at low Reynolds number. These active agents are subject to strong stochastic fluctuations, that compete with the directed motion. So far most studies consider the lowest order moments of the displacements only, while more general spatio-temporal information on the stochastic motion is provided in scattering experiments. Here we derive analytically exact expressions for the directly measurable intermediate scattering function for a mesoscopic model of a single, anisotropic active Brownian particle in three dimensions. The mean-square displacement and the non-Gaussian parameter of the stochastic process are obtained as derivatives of the intermediate scattering function. These display different temporal regimes dominated by effective diffusion and directed motion due to the interplay of translational and rotational diffusion which is rationalized within the theory. The most prominent feature of the intermediate scattering function is an oscillatory behavior at intermediate wavenumbers reflecting the persistent swimming motion, whereas at small length scales bare translational and at large length scales an enhanced effective diffusion emerges. We anticipate that our characterization of the motion of active agents will serve as a reference for more realistic models and experimental observations.

  16. Reconciling measured scattering response of 3D metamaterials with simulation

    Directory of Open Access Journals (Sweden)

    Adomanis Bryan M.

    2015-01-01

    Full Text Available Membrane projection lithography is used to create 3-dimensional unit cells in a silicon matrix decorated with metallic inclusions. The structures show pronounced resonances in the 4–16 µm wavelength range and demonstrate direct coupling to the magnetic field of a normally incident transverse electromagnetic (TEM wave, a behavior only possible for vertically oriented resonators. Qualitative agreement between rigorous coupled wave analysis (RCWA simulation and measured scattering response is shown. COMSOL simulations show that slight variations in both metallic inclusion and silicon unit cell physical dimensions can have large impact in the scattering response, so that design for manufacture of 3D metamaterial structures for applications should be done with care.

  17. Measurements and simulation of ionospheric scattering on VHF and UHF radar signals: Channel scattering function

    Science.gov (United States)

    Rogers, Neil C.; Cannon, Paul S.; Groves, Keith M.

    2009-02-01

    The design and operation of transionospheric VHF and UHF radars requires knowledge of amplitude and phase scintillation due to ionospheric scattering. Phase coherence is of particular importance where long coherent integration periods and large bandwidths are required. A thin phase screen, parabolic equation based, Trans-Ionospheric Radio Propagation Simulator (TIRPS) is described. Modeled channel scattering functions (CSFs) are compared to experimental VHF and UHF data derived from the Advanced Research Projects Agency Long-range Tracking and Instrumentation Radar on Kwajalein Island (9.4°N, 166.8°E). TIRPS quantitatively reproduces the experimental results, including the quasi-parabolic profile observed in the measured CSFs under strong turbulence conditions. Variations in the simulated CSF with ionospheric phase screen parameters are also presented. Under conditions of high integrated strength of turbulence (CkL), a low phase spectral index (p = 1), indicating relatively dense small-scale irregularities, produces pronounced range spreading. Conversely, when the spectral index is high (p = 4), indicative of strong focusing/defocusing by large-scale irregularities, there is increased Doppler spreading and, when the outer scale of irregularities is large, a greater likelihood of asymmetry of the CSF about the zero Doppler axis.

  18. Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies

    Science.gov (United States)

    Albers, D.; Bisplinghoff, J.; Bollmann, R.; Büßer, K.; Cloth, P.; Daniel, R.; Diehl, O.; Dohrmann, F.; Engelhardt, H. P.; Ernst, J.; Eversheim, P. D.; Gasthuber, M.; Gebel, R.; Greiff, J.; Groß, A.; Groß-Hardt, R.; Heider, S.; Heine, A.; Hinterberger, F.; Igelbrink, M.; Jahn, R.; Jeske, M.; Lahr, U.; Langkau, R.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuk, T.; Mosel, F.; Müller, M.; Münstermann, M.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; Roß, U.; von Rossen, P.; Scheid, H.; Schirm, N.; Schulz-Rojahn, M.; Schwandt, F.; Schwarz, V.; Scobel, W.; Sterzenbach, G.; Trelle, H. J.; Wellinghausen, A.; Wiedmann, W.; Woller, K.; Ziegler, R.

    1997-03-01

    Excitation functions of proton-proton elastic scattering cross sections have been measured in narrow steps for projectile momenta pp (energies Tp) from 1100 to 3300 MeV/c (500 to 2500 MeV) in the angular range 35°<=Θc.m.<=90° with a detector providing ΔΘc.m.~1.4° resolution. Measurements have been performed continuously during projectile acceleration in the cooler synchrotron COSY with an internal CH2 fiber target, taking particular care to monitor luminosity as a function of Tp. The advantages of this experimental technique are demonstrated, and the excitation functions obtained are compared to existing cross section data. No evidence for narrow structures was found.

  19. Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies

    Energy Technology Data Exchange (ETDEWEB)

    Bisplinghoff, J.; Daniel, R.; Diehl, O.; Engelhardt, H.; Ernst, J.; Eversheim, P.; Gro-Hardt, R.; Heider, S.; Heine, A.; Hinterberger, F.; Jahn, R.; Jeske, M.; Lahr, U.; Maschuw, R.; Mayer-Kuckuk, T.; Mosel, F.; Rohdje, H.; Rosendaal, D.; Ro, U.; Scheid, H.; Schulz-Rojahn, M.; Schwandt, F.; Schwarz, V.; Trelle, H.; Wiedmann, W.; Ziegler, R. [Inst.fuer Strahlen- und Kernphysik, Universitaet Bonn, D-53115 Bonn (Germany); Albers, D.; Bollmann, R.; Bueer, K.; Dohrmann, F.; Gasthuber, M.; Greiff, J.; Gro, A.; Igelbrink, M.; Langkau, R.; Lindlein, J.; Mueller, M.; Muenstermann, M.; Schirm, N.; Scobel, W.; Wellinghausen, A.; Woller, K. [I. Inst.fuer Experimentalphysik, Universitaet Hamburg, D-22761 Hamburg (Germany); Cloth, P.; Gebel, R.; Maier, R.; Prasuhn, D.; von Rossen, P.; Sterzenbach, G. [Inst.fuer Kernphysik, KFA Juelich, Juelich (Germany)

    1997-03-01

    Excitation functions of proton-proton elastic scattering cross sections have been measured in narrow steps for projectile momenta p{sub p} (energies T{sub p}) from 1100 to 3300MeV/c (500 to 2500MeV) in the angular range 35{degree}{le}{Theta}{sub c.m.}{le}90{degree} with a detector providing {Delta}{Theta}{sub c.m.}{approx}1.4{degree} resolution. Measurements have been performed continuously during projectile acceleration in the cooler synchrotron COSY with an internal CH{sub 2} fiber target, taking particular care to monitor luminosity as a function of T{sub p}. The advantages of this experimental technique are demonstrated, and the excitation functions obtained are compared to existing cross section data. No evidence for narrow structures was found. {copyright} {ital 1997} {ital The American Physical Society}

  20. Lidar measurements of cloud extinction coefficient distribution and its forward scattering phase function according to multiply scattered lidar returns

    Science.gov (United States)

    Qiu, Jinhuan; Huang, Qirong

    1992-01-01

    The study of the inversion algorithm for the single scatter lidar equation, for quantitative determination of cloud (or aerosol) optical properties, has received much attention over the last thirty years. Some of the difficulties associated with the solution of this equation are not yet solved. One problem is that a single scatter lidar equation has two unknowns. Because of this, the determination of the far-end boundary value, in the case of Klett's algorithm, is a problem if the atmosphere is optically inhomogeneous. Another difficulty concerns multiple scattering. There is a large error in the extinction distribution solution, in many cases, if only the single scattering component is considered, while neglecting the multiple scattering component. However, the use of multiple scattering in the remote sensing of aerosol or cloud optical properties is promising. In our early study, an inversion method for simultaneous determination of the cloud (or aerosol) Extinction Coefficient Distribution (ECD) and its Forward Scattering Phase Function (FSPF) was proposed according to multiply scattered lidar returns with two fields of view for the receiver. The method is based on a parameterized multiple scatter lidar equation. This paper is devoted to further numerical tests and an experimental study of lidar measurements of cloud ECD and FSPF using this method.

  1. Scattering Response of Sucrose Clusters with Intense XFEL Pulses in Water Window

    Science.gov (United States)

    Ho, Phay; Benedikt Daurer, Benedikt; Bielecki, Johan; Hantke, Max; Maia, Filipe; Knight, Chris; Hajdu, Janos; Young, Linda; Bostedt, Christoph

    2017-04-01

    We present a combined experimental and theoretical study about the effects of non-linear x-ray ionization dynamics on the scattering response of molecular clusters in the soft x-ray regime that includes and goes beyond the water window. Nanosized sucrose clusters were irradiated with intense XFEL pulses (photon energy from 500 to 1500 eV and pulse duration of 180 fs). Surprisingly, the measured scattering signals near the oxygen K-edge in the water window are found to be substantially smaller than those at higher photon energies. We employ Monte-Carlo/Molecular Dynamics calculations to investigate the x-ray processes as a function of pulse parameters (photon energy, bandwidth and pulse duration) and cluster size. We demonstrate the important role of resonant excitation (RE) in the molecular scattering response in the water window. In particular, 1s ->2p RE cycling enabled in the oxygen atom/ion provide additional ionization pathways which, combined with the long pulse duration, lead to substantial reduction in scattering power of sugar clusters for photon energies just below the oxygen K-edge. Supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, US Dept of Energy, Contract DE-AC02-06CH11357.

  2. Structure function for high-concentration biophantoms of polydisperse scatterer sizes.

    Science.gov (United States)

    Han, Aiguo; O'Brien, William

    2015-02-01

    Ultrasonic backscattering coefficient (BSC) has been used extensively to characterize tissue. In most cases, sparse scatterer concentrations are assumed. However, many types of tissues have dense scattering media. This study addresses the problem of dense media scattering by taking into account the correlation among scatterers using the structure functions. The effect of scatterer polydispersity on the structure functions is investigated. Structure function models based on polydisperse scatterers are theoretically developed and experimentally evaluated against the structure functions obtained from cell pellet biophantoms. The biophantoms were constructed by placing live cells of known concentration in coagulation media to form a clot. The BSCs of the biophantoms were estimated using single-element transducers over the frequency range from 11 to 105 MHz. Experimental structure functions were obtained by comparing the BSCs of two cell concentrations. The structure functions predicted by the models agreed with the experimental structure functions. Fitting the models yielded cell radius estimates that were consistent with direct light microscope measures. The results demonstrate the role of scatterer position correlation on dense media scattering, and the significance of scatterer polydispersity on structure functions. This work may lead to more accurate modeling of ultrasonic scattering in dense medium for improved tissue characterization.

  3. Nuclear dependence of structure functions in the shadowing region of deep inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Berger, E.L.; Qiu, Jianwei

    1988-07-27

    A discussion of nuclear shadowing in deep inelastic lepton scattering is presented. We show that the parton recombination model suggests that shadowing should begin to occur at larger values of Bjorken x as A increases. This expectation as well as that of weak dependence on Q/sup 2/, and the trend of the x dependence of the shadowing phenomenon are consistent with recent data. Shadowing at small x is combined with nuclear bound state effects, responsible for nuclear dependence at larger x, to provide description of the A dependence of the structure function for the entire range of x. 21 refs., 5 figs.

  4. Phase-shift effect of amplitude spread function on spectrum and image formation in coherent Raman scattering microspectroscopy.

    Science.gov (United States)

    Fukutake, Naoki

    2016-03-01

    Coherent Raman scattering microspectroscopy, which includes coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microspectroscopy, permits label-free hyperspectral imaging. We report the theoretical study of the phase-shift effect of the impulse response function on the spectral and image-forming properties of coherent Raman scattering microspectroscopy. We show that the spectrum and image are influenced by not only the NA of objective for excitation (NA(ex)) but also that for signal collection (NA(col)), in association with the phase-shift effect. We discuss that, under the condition NA(ex)≠NA(col), both the spectrum and the image become deformed by the phase-shift effect, which can be applied to the direct measurement of the imaginary part of the nonlinear susceptibility in CARS spectroscopy. We point out that, even in SRS microscopy, the nonresonant background can contribute to the image formation and cause the artifact in the image.

  5. NaI(Tl) response functions

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R.; Ortiz R, J. M. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Benites R, J. L. [Centro Estatal de Cancerologia de Nayarit, Calz. de la Cruz 118 Sur, Tepic, Nayarit (Mexico); De Leon M, H. A., E-mail: fermineutron@yahoo.com.mx [Instituto Tecnologico de Aguascalientes, Av. Adolfo Lopez Mateos 1801 Ote., 20155 Aguascalientes, Ags. (Mexico)

    2015-09-15

    The response functions of a NaI(Tl) detector have been estimated using Monte Carlo methods. Response functions were calculated for monoenergetic photon sources (0.05 to 3 MeV). Responses were calculated for point-like sources and for sources distributed in Portland cement cylinders. The responses were used to calculate the efficiency functions in term of photon energy. Commonly, sources used for calibration are point-like, and eventually sources to be measured have different features. In order to use the calibrated sources corrections due to solid angle, self-absorption and scattering, must be carried out. However, some of these corrections are not easy to perform. In this work, the calculated responses were used to estimate the detector efficiency of point-like sources, and sources distributed in Portland type cement. Samples of Portland paste were prepared and were exposed to photoneutrons produced by a 15 MV linac. Some of the elements in the cement were activated producing γ-emitting radionuclides that were measured with a NaI(Tl) gamma-ray spectrometer, that was calibrated with point-like sources. In order to determine the specific activity in the induced radioisotopes calculated efficiencies were used to make corrections due to the differences between the solid angle, photon absorption and photon scattering in the point-like calibration sources and the sources distributed in cement. During the interaction between photoneutrons and the cement samples three radioisotopes were induced: {sup 56}Mn, {sup 24}Na, and {sup 28}Al. (Author)

  6. Next-to-leading order hard scattering using fully unintegrated parton distribution functions

    NARCIS (Netherlands)

    Rogers, T.C.

    2008-01-01

    We calculate the next-to-leading order fully unintegrated hard scattering coefficient for unpolarized gluon-induced deep inelastic scattering using the logical framework of parton correlation functions developed in previous work. In our approach, exact four-momentum conservation is maintained

  7. Optimized goniometer for determination of the scattering phase function of suspended particles: simulations and measurements.

    Science.gov (United States)

    Foschum, Florian; Kienle, Alwin

    2013-08-01

    We present simulations and measurements with an optimized goniometer for determination of the scattering phase function of suspended particles. We applied the Monte Carlo method, using a radially layered cylindrical geometry and mismatched boundary conditions, in order to investigate the influence of reflections caused by the interfaces of the glass cuvette and the scatterer concentration on the accurate determination of the scattering phase function. Based on these simulations we built an apparatus which allows direct measurement of the phase function from ϑ=7  deg to ϑ=172  deg without any need for correction algorithms. Goniometric measurements on polystyrene and SiO2 spheres proved this concept. Using the validated goniometer, we measured the phase function of yeast cells, demonstrating the improvement of the new system compared to standard goniometers. Furthermore, the scattering phase function of different fat emulsions, like Intralipid, was determined precisely.

  8. Temperature-dependent structural and functional features of a hyperthermostable enzyme using elastic neutron scattering

    NARCIS (Netherlands)

    Koutsopoulos, S; van der Oost, J; Norde, W

    2005-01-01

    The dynamic behavior of an endoglucanase from the hyperthermophilic microorganism Pyrococcus furiosus was investigated using elastic neutron scattering. The temperature dependence of the atomic motions was correlated with conformational. and functional characteristics of the enzyme. The onset of

  9. Phase function measurements on nonspherical scatterers using a two-axis goniometer.

    Science.gov (United States)

    Forster, Florian Klaus; Kienle, Alwin; Michels, Rene; Hibst, Raimund

    2006-01-01

    We present a two-axis goniometer for measuring the phase function of scattering media with an angular resolution of about 0.2 deg having 12 decades of dynamic range and covering almost the full solid angle. The setup is evaluated with polystyrene spheres and with perpendicularly and obliquely illuminated thin glass cylinders. The scattering pattern and its intensity distribution are in excellent agreement with analytical theory. A multiple scattering configuration composed of two parallel cylinders is also examined. Finally, the phase function of dentin slabs is measured and its dependence on the dental microstructure is discussed.

  10. First Measurement of the Low- x, Low- Q2 Structure Function F2 in Neutrino Scattering

    Science.gov (United States)

    Fleming, B. T.; Adams, T.; Alton, A.; Arroyo, C. G.; Avvakumov, S.; de Barbaro, L.; de Barbaro, P.; Bazarko, A. O.; Bernstein, R. H.; Bodek, A.; Bolton, T.; Brau, J.; Buchholz, D.; Budd, H.; Bugel, L.; Conrad, J.; Drucker, R. B.; Formaggio, J. A.; Frey, R.; Goldman, J.; Goncharov, M.; Harris, D. A.; Johnson, R. A.; Kim, J. H.; King, B. J.; Kinnel, T.; Koutsoliotas, S.; Lamm, M. J.; Marsh, W.; Mason, D.; McFarland, K. S.; McNulty, C.; Mishra, S. R.; Naples, D.; Nienaber, P.; Romosan, A.; Sakumoto, W. K.; Schellman, H.; Sciulli, F. J.; Seligman, W. G.; Shaevitz, M. H.; Smith, W. H.; Spentzouris, P.; Stern, E. G.; Suwonjandee, N.; Vaitaitis, A.; Vakili, M.; Yang, U. K.; Yu, J.; Zeller, G. P.; Zimmerman, E. D.

    2001-06-01

    A new structure function analysis of CCFR deep inelastic ν-N and ν¯-N scattering data is presented for previously unexplored kinematic regions down to Bjorken x = 0.0045 and Q2 = 0.3 GeV2. Comparisons to charged lepton scattering data from NMC and E665 experiments are made and the behavior of the structure function Fν2 is studied in the limit Q2-->0.

  11. Scattering Properties of Jovian Tropospheric Cloud Particles from Cassini/ISS: Mie Scattering Phase Function and Particle Size in the South Tropical Zone

    Science.gov (United States)

    Sato, Takao M.; Satoh, T.; Kasaba, Y.

    2010-10-01

    It is essential to know scattering properties (e.g., scattering phase function) of clouds for determination of vertical cloud structure. However, we cannot derive those from ground-based and Earth-orbit observations because of the limitation of solar phase angle as viewed from the Earth. Then, most previous studies have used the scattering phase function deduced from the Pioneer 10/IPP data (blue: 440 nm, red: 640nm) [Tomasko et al., 1978]. There are two shortcomings in the Pioneer scattering phase function. One is that we have to use this scattering phase function at red as a substitute for analyses of imaging photometry using CH4 bands (center: 727 and 890 nm), although clouds should have wavelength dependency. The other is that the red pass band of IPP was so broad (595-720 nm) that this scattering phase function in red just show wavelength-averaged scattering properties of clouds. To provide a new reference scattering phase function with wavelength dependency, we have analyzed the Cassini/ISS data in BL1 (451 nm), CB1 (619 nm), CB2 (750 nm), and CB3 (938 nm) over wide solar phase angles (3-141 degrees) during its Jovian flyby in 2000-2001. A simple cloud model which consists of a thin stratospheric haze, a semi-infinite cloud, and an intervening Rayleigh gas layers is adopted. Applying Mie theory to scattering by clouds, we deduce the scattering phase function of cloud and effective particle size in the South Tropical Zone. When we use the nominal value of reflective index for ammonia ice (Martonchik et al., 1984), we cannot obtain reasonable fit to the observed limb-darkening profiles. This would imply that we should consider possible effects on the impurity and/or the nonsphericiy of clouds. In this presentation, we will show detail model description and these results. Finally, we discuss scattering properties of clouds through comparison with previous works.

  12. A coupled bispectral, temporal and spatial coherence function of the pressure field, scattered from a moving sea surface (A)

    DEFF Research Database (Denmark)

    Bjerrum-Niese, Christian; Jensen, Leif Bjørnø

    1995-01-01

    Fluctuations in the scattering of high-frequency sound from the moving sea surface is of significance, particularly in underwater acoustic communication systems using adaptive methods. Surface scattering may statistically be described using coherence functions, especially for higher frequencies...

  13. Detailed analysis of Rouse mode and dynamic scattering function of highly entangled polymer melts in equilibrium

    Science.gov (United States)

    Hsu, Hsiao-Ping; Kremer, Kurt

    2017-03-01

    We present large-scale molecular dynamics simulations for a coarse-grained model of polymer melts in equilibrium. From detailed Rouse mode analysis we show that the time-dependent relaxation of the autocorrelation function (ACF) of modes p can be well described by the effective stretched exponential function due to the crossover from Rouse to reptation regime. The ACF is independent of chain sizes N for N/p reptation regime. We have also provided evidence that the incoherent dynamic scattering function follows the same crossover scaling behavior of the mean square displacement of monomers at the corresponding characteristic time scales. The decay of the coherent dynamic scattering function is slowed down and a plateau develops as chain sizes increase at the intermediate time and wave length scales. The tube diameter extracted from the coherent dynamic scattering function is equivalent to the previous estimate from the mean square displacement of monomers.

  14. Morphology effect on the light scattering and dynamic response of polymer network liquid crystal phase modulator.

    Science.gov (United States)

    Xiangjie, Zhao; Cangli, Liu; Jiazhu, Duan; Jiancheng, Zeng; Dayong, Zhang; Yongquan, Luo

    2014-06-16

    Polymer network liquid crystal (PNLC) was one of the most potential liquid crystal for submillisecond response phase modulation, which was possible to be applied in submillisecond response phase only spatial light modulator. But until now the light scattering when liquid crystal director was reoriented by external electric field limited its phase modulation application. Dynamic response of phase change when high voltage was applied was also not elucidated. The mechanism that determines the light scattering was studied by analyzing the polymer network morphology by SEM method. Samples were prepared by varying the polymerization temperature, UV curing intensity and polymerization time. The morphology effect on the dynamic response of phase change was studied, in which high voltage was usually applied and electro-striction effect was often induced. The experimental results indicate that the polymer network morphology was mainly characterized by cross linked single fibrils, cross linked fibril bundles or even both. Although the formation of fibril bundle usually induced large light scattering, such a polymer network could endure higher voltage. In contrast, although the formation of cross linked single fibrils induced small light scattering, such a polymer network cannot endure higher voltage. There is a tradeoff between the light scattering and high voltage endurance. The electro-optical properties such as threshold voltage and response time were taken to verify our conclusion. For future application, the monomer molecular structure, the liquid crystal solvent and the polymerization conditions should be optimized to generate optimal polymer network morphology.

  15. Introduction to neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W.E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    We give here an introduction to the theoretical principles of neutron scattering. The relationship between scattering- and correlation-functions is particularly emphasized. Within the framework of linear response theory (justified by the weakness of the basic interaction) the relation between fluctuation and dissipation is discussed. This general framework explains the particular power of neutron scattering as an experimental method. (author) 4 figs., 4 refs.

  16. Submillisecond-response and scattering-free infrared liquid crystal phase modulators.

    Science.gov (United States)

    Sun, Jie; Chen, Yuan; Wu, Shin-Tson

    2012-08-27

    We demonstrate a submillisecond-response and scattering-free infrared phase modulator using a polymer network liquid crystal (PNLC). The required voltage for achieving 2π phase change at λ = 1.06 µm is 70V (or 5.8 V/μm) and the measured response time is ~200 µs at 25°C and 30 µs at 70°C. Opposite to our conventional understanding, a high viscosity LC helps to achieve small domain size during polymerization process, which in turn reduces the response time and light scattering. We use Rayleigh-Gans-Debye scattering model to analyze the voltage-on state transmission spectra. When the domain size is comparable to the wavelength, the model fits with experimental results well. But when the domain size is smaller than the wavelength, the simple Rayleigh model works well.

  17. Scattering Phase Functions of Constituents of Mineral Dust Aerosols ...

    African Journals Online (AJOL)

    The results show that there is increasing asymmetry and complexity of the phase functions with increasing radial sizes for each of the selected constituents: Illite, Kaolinite, Montmorillonte, Hematite, Calcite and Quartz. The behaviour of these constituents as observed by their phase functions provide information on the ...

  18. Scattering Phase Functions of Constituents of Mineral Dust Aerosols ...

    African Journals Online (AJOL)

    In this paper, a Mie-based numerical computation and visualization program has been used to compute the phase functions of typical constituents of mineral dust ... The behaviour of these constituents as observed by their phase functions provide information on the optical properties and radiative effects of the mineral dust ...

  19. Quasielastic Scattering from Relativistic Bound Nucleons: Transverse-Longitudinal Response

    Energy Technology Data Exchange (ETDEWEB)

    Udias, J. M. [Instituto de Estructura de la Materia, CSIC Serrano 123, E-28006 Madrid, (Spain); Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid, (Spain); Caballero, J. A. [Instituto de Estructura de la Materia, CSIC Serrano 123, E-28006 Madrid, (Spain); Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla, (Spain); Moya de Guerra, E. [Instituto de Estructura de la Materia, CSIC Serrano 123, E-28006 Madrid, (Spain); Amaro, J. E. [Departamento de Fisica Moderna, Universidad de Granada, E-18071 Granada, (Spain); Donnelly, T. W. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1999-12-27

    Predictions for electron induced proton knockout from p{sub 1/2} and p{sub 3/2} shells in {sup 16}O are presented using various approximations for the relativistic nucleonic current. Results for differential cross section, transverse-longitudinal response (R{sub TL} ), and left-right asymmetry A{sub TL} are compared at |Q{sup 2}|=0.8(GeV/c){sup 2} . We show that there are important dynamical and kinematical relativistic effects which can be tested by experiment. (c) 1999 The American Physical Society.

  20. A fast iterative method for Chandrasekhar's -functions for general laws of scattering

    Science.gov (United States)

    Kawabata, Kiyoshi

    2015-08-01

    This work shows that notable acceleration of the speed of calculating Chandrasekhar's -functions for general laws of scattering with an iterative method can be realized by supplying a starting approximation produced by the following procedure: (i) in the cases of azimuth-angle independent Fourier components, values of the isotropic scattering -function given by an accurate yet simple-to-apply formula, in particular, the one by Kawabata and Limaye (Astrophys. Space Sci. 332:365, 2011), and (ii) for azimuth-angle dependent Fourier components, an already obtained solution of the next lower order term.

  1. Generalized theory of resonance scattering (GTRS) using the translational addition theorem for spherical wave functions.

    Science.gov (United States)

    Mitri, Farid

    2014-11-01

    The generalized theory of resonance scattering (GTRS) by an elastic spherical target in acoustics is extended to describe the arbitrary scattering of a finite beam using the addition theorem for the spherical wave functions of the first kind under a translation of the coordinate origin. The advantage of the proposed method over the standard discrete spherical harmonics transform previously used in the GTRS formalism is the computation of the off-axial beam-shape coefficients (BSCs) stemming from a closed-form partial-wave series expansion representing the axial BSCs in spherical coordinates. With this general method, the arbitrary acoustical scattering can be evaluated for any particle shape and size, whether the particle is partially or completely illuminated by the incident beam. Numerical examples for the axial and off-axial resonance scattering from an elastic sphere placed arbitrarily in the field of a finite circular piston transducer with uniform vibration are provided. Moreover, the 3-D resonance directivity patterns illustrate the theory and reveal some properties of the scattering. Numerous applications involving the scattering phenomenon in imaging, particle manipulation, and the characterization of multiphase flows can benefit from the present analysis because all physically realizable beams radiate acoustical waves from finite transducers as opposed to waves of infinite extent.

  2. Excitation function of elastic $pp$ scattering from a unitarily extended Bialas-Bzdak model

    CERN Document Server

    Nemes, F.; Csanád, M.

    2015-01-01

    The Bialas-Bzdak model of elastic proton-proton scattering assumes a purely imaginary forward scattering amplitude, which consequently vanishes at the diffractive minima. We extended the model to arbitrarily large real parts in a way that constraints from unitarity are satisfied. The resulting model is able to describe elastic $pp$ scattering not only at the lower ISR energies but also at $\\sqrt{s}=$7~TeV in a statistically acceptable manner, both in the diffractive cone and in the region of the first diffractive minimum. The total cross-section as well as the differential cross-section of elastic proton-proton scattering is predicted for the future LHC energies of $\\sqrt{s}=$13, 14, 15~TeV and also to 28~TeV. A non-trivial, significantly non-exponential feature of the differential cross-section of elastic proton-proton scattering is analyzed and the excitation function of the non-exponential behavior is predicted. The excitation function of the shadow profiles is discussed and related to saturation at small ...

  3. Ordinary mode reflectometry. Modification of the scattering and cut-off responses due to the shape of localized density fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Fanack, C.; Boucher, I.; Heuraux, S.; Leclert, G. [Centre National de la Recherche Scientifique (CNRS), 54 - Nancy (France). Lab. de Physique du Solide; Clairet, F.; Zou, X.L. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    1996-01-01

    Ordinary wave reflectometry in a plasma containing a localized density perturbation is studied with a 1-D model. The phase response is studied as a function of the wavenumber and position of the perturbation. It is shown that it strongly depends upon the perturbation shape and size. For a small perturbation wavenumber, the response is due to the oscillation of the cut-off layer. For larger wavenumbers, two regimes are found: for a broad perturbation, the phase response is an image of the perturbation itself; for a narrow perturbation, it is rather an image of the Fourier transform. For tokamak plasmas it turns out that, for the fluctuation spectra usually observed, the phase response comes primarily from those fluctuations that are localized at the cut-off. Results of a 2-D numerical model show that geometry effects are negligible for the scattering by radial fluctuations. (author). 18 refs.

  4. Light source distribution and scattering phase function influence light transport in diffuse multi-layered media

    Science.gov (United States)

    Vaudelle, Fabrice; L'Huillier, Jean-Pierre; Askoura, Mohamed Lamine

    2017-06-01

    Red and near-Infrared light is often used as a useful diagnostic and imaging probe for highly scattering media such as biological tissues, fruits and vegetables. Part of diffusively reflected light gives interesting information related to the tissue subsurface, whereas light recorded at further distances may probe deeper into the interrogated turbid tissues. However, modelling diffusive events occurring at short source-detector distances requires to consider both the distribution of the light sources and the scattering phase functions. In this report, a modified Monte Carlo model is used to compute light transport in curved and multi-layered tissue samples which are covered with a thin and highly diffusing tissue layer. Different light source distributions (ballistic, diffuse or Lambertian) are tested with specific scattering phase functions (modified or not modified Henyey-Greenstein, Gegenbauer and Mie) to compute the amount of backscattered and transmitted light in apple and human skin structures. Comparisons between simulation results and experiments carried out with a multispectral imaging setup confirm the soundness of the theoretical strategy and may explain the role of the skin on light transport in whole and half-cut apples. Other computational results show that a Lambertian source distribution combined with a Henyey-Greenstein phase function provides a higher photon density in the stratum corneum than in the upper dermis layer. Furthermore, it is also shown that the scattering phase function may affect the shape and the magnitude of the Bidirectional Reflectance Distribution (BRDF) exhibited at the skin surface.

  5. Velocity-Autocorrelation Function in Liquids, Deduced from Neutron Incoherent Scattering Results

    DEFF Research Database (Denmark)

    Carneiro, Kim

    1976-01-01

    The Fourier transform p(ω) of the velocity-autocorrelation function is derived from neutron incoherent scattering results, obtained from the two liquids Ar and H2. The quality and significance of the results are discussed with special emphasis on the long-time t-3/2 tail, found in computer...

  6. Autocorrelation function of scattered light for a binary fluid near the critical mixing point

    Science.gov (United States)

    Bendjaballah, C.

    1973-01-01

    A time-to-amplitude conversion technique was applied to measure the second-order autocorrelation function of light scattering by a binary fluid from concentration fluctuations of the fluid very close to the critical point. The experimental setup included two photomultipliers, a time-to-amplitude converter, and a pulse height analyzer.

  7. Electron-phonon scattering from Green’s function transport combined with molecular dynamics

    DEFF Research Database (Denmark)

    Markussen, Troels; Palsgaard, Mattias Lau Nøhr; Stradi, Daniele

    2017-01-01

    We present a conceptually simple method for treating electron-phonon scattering and phonon limited mobilities. By combining Green’s function based transport calculations and molecular dynamics, we obtain a temperature dependent transmission from which we evaluate the mobility. We validate our...

  8. Coupling External Radiation Transport Code Results to the GADRAS Detector Response Function

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Dean J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Contraband Detection; Thoreson, Gregory G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Contraband Detection; Horne, Steven M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Contraband Detection

    2014-01-01

    Simulating gamma spectra is useful for analyzing special nuclear materials. Gamma spectra are influenced not only by the source and the detector, but also by the external, and potentially complex, scattering environment. The scattering environment can make accurate representations of gamma spectra difficult to obtain. By coupling the Monte Carlo Nuclear Particle (MCNP) code with the Gamma Detector Response and Analysis Software (GADRAS) detector response function, gamma spectrum simulations can be computed with a high degree of fidelity even in the presence of a complex scattering environment. Traditionally, GADRAS represents the external scattering environment with empirically derived scattering parameters. By modeling the external scattering environment in MCNP and using the results as input for the GADRAS detector response function, gamma spectra can be obtained with a high degree of fidelity. This method was verified with experimental data obtained in an environment with a significant amount of scattering material. The experiment used both gamma-emitting sources and moderated and bare neutron-emitting sources. The sources were modeled using GADRAS and MCNP in the presence of the external scattering environment, producing accurate representations of the experimental data.

  9. Functional materials analysis using in situ and in operando X-ray and neutron scattering.

    Science.gov (United States)

    Peterson, Vanessa K; Papadakis, Christine M

    2015-03-01

    In situ and in operando studies are commonplace and necessary in functional materials research. This review highlights recent developments in the analysis of functional materials using state-of-the-art in situ and in operando X-ray and neutron scattering and analysis. Examples are given covering a number of important materials areas, alongside a description of the types of information that can be obtained and the experimental setups used to acquire them.

  10. Functional materials analysis using in situ and in operando X-ray and neutron scattering

    Directory of Open Access Journals (Sweden)

    Vanessa K. Peterson

    2015-03-01

    Full Text Available In situ and in operando studies are commonplace and necessary in functional materials research. This review highlights recent developments in the analysis of functional materials using state-of-the-art in situ and in operando X-ray and neutron scattering and analysis. Examples are given covering a number of important materials areas, alongside a description of the types of information that can be obtained and the experimental setups used to acquire them.

  11. Functional materials analysis using in situ and in operando X-ray and neutron scattering

    Science.gov (United States)

    Peterson, Vanessa K.; Papadakis, Christine M.

    2015-01-01

    In situ and in operando studies are commonplace and necessary in functional materials research. This review highlights recent developments in the analysis of functional materials using state-of-the-art in situ and in operando X-ray and neutron scattering and analysis. Examples are given covering a number of important materials areas, alongside a description of the types of information that can be obtained and the experimental setups used to acquire them. PMID:25866665

  12. Relationship between the atomic pair distribution function and small angle scattering: implications for modeling of nanoparticles

    OpenAIRE

    Farrow, Christopher L.; Billinge, Simon J. L.

    2008-01-01

    Here we show explicitly the relationship between the functions used in the atomic pair distribution function (PDF) method and those commonly used in small angle scattering (SAS) analyses. The origin of the sloping baseline, $-4\\pi r\\rho_0$, in PDFs of bulk materials is identified as originating from the SAS intensity that is neglected in PDF measurements. The non-linear baseline in nanoparticles has the same origin, and contains information about the shape and size of the nanoparticles.

  13. Long-term effect of surface light scattering and glistenings of intraocular lenses on visual function.

    Science.gov (United States)

    Hayashi, Ken; Hirata, Akira; Yoshida, Motoaki; Yoshimura, Koichi; Hayashi, Hideyuki

    2012-08-01

    To investigate the long-term effect of surface light scattering and glistenings of various intraocular lenses (IOLs) on visual function and optical aberrations after cataract surgery. Case-control study. Thirty-five eyes that underwent implantation of a hydrophobic acrylic, silicone, or polymethyl methacrylate (PMMA) IOL more than 10 years ago were recruited. The scattering light intensity of the surface and internal matrix of the optic was measured using Scheimpflug photography. Visual acuity (VA) was measured using VA charts, and contrast VA and that with glare (glare VA) were examined using a contrast sensitivity tester. Ocular higher-order aberrations (HOAs) were measured using a Hartmann-Shack aberrometer. Mean scattering light intensity of the surface and internal matrix of the optic was significantly higher in the acrylic group than in the silicone and PMMA groups (P ocular and internal optic HOAs in the acrylic group. At more than 10 years postoperatively, visual function, including contrast sensitivity, and ocular HOAs were comparable among eyes that received acrylic, silicone, and PMMA IOLs. Surface scattering and glistenings with the acrylic IOLs were not significantly correlated with visual function and optical aberrations. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Study of scattering cross section of a plasma column using Green's function volume integral equation method

    Science.gov (United States)

    Soltanmoradi, Elmira; Shokri, Babak

    2017-05-01

    In this article, the electromagnetic wave scattering from plasma columns with inhomogeneous electron density distribution is studied by the Green's function volume integral equation method. Due to the ready production of such plasmas in the laboratories and their practical application in various technological fields, this study tries to find the effects of plasma parameters such as the electron density, radius, and pressure on the scattering cross-section of a plasma column. Moreover, the incident wave frequency influence of the scattering pattern is demonstrated. Furthermore, the scattering cross-section of a plasma column with an inhomogeneous collision frequency profile is calculated and the effect of this inhomogeneity is discussed first in this article. These results are especially used to determine the appropriate conditions for radar cross-section reduction purposes. It is shown that the radar cross-section of a plasma column reduces more for a larger collision frequency, for a relatively lower plasma frequency, and also for a smaller radius. Furthermore, it is found that the effect of the electron density on the scattering cross-section is more obvious in comparison with the effect of other plasma parameters. Also, the plasma column with homogenous collision frequency can be used as a better shielding in contrast to its inhomogeneous counterpart.

  15. Covariant spectator theory of $np$ scattering:\\\\ Effective range expansions and relativistic deuteron wave functions

    Energy Technology Data Exchange (ETDEWEB)

    Franz Gross, Alfred Stadler

    2010-09-01

    We present the effective range expansions for the 1S0 and 3S1 scattering phase shifts, and the relativistic deuteron wave functions that accompany our recent high precision fits (with \\chi^2/N{data} \\simeq 1) to the 2007 world np data below 350 MeV. The wave functions are expanded in a series of analytical functions (with the correct asymptotic behavior at both large and small arguments) that can be Fourier-transformed from momentum to coordinate space and are convenient to use in any application. A fortran subroutine to compute these wave functions can be obtained from the authors.

  16. Elastodynamic Green's function retrieval through single-sided Marchenko inverse scattering.

    Science.gov (United States)

    da Costa Filho, Carlos Alberto; Ravasi, Matteo; Curtis, Andrew; Meles, Giovanni Angelo

    2014-12-01

    The solution of the inverse scattering problem for the one-dimensional Schrödinger equation is given by the Marchenko equation. Recently, a Marchenko-type equation has been derived for three-dimensional (3D) acoustic wave fields, whose solution has been shown to recover the Green's functions from points within the medium to its exterior, using only single-sided scattered data. Here we extend this approach to 3D vectorial wave fields that satisfy the elastodynamic wave equation and recover Green's functions from points interior to an elastic, solid-state medium from purely external and one-sided measurements. The method is demonstrated in a solid-earth-like model to construct Green's functions using only subsurface sources, from earth-surface force and deformation sources and particle velocity and stress measurements.

  17. Solution-based characterization of surface-enhanced Raman response of single scattering centers

    Energy Technology Data Exchange (ETDEWEB)

    Laurence, T A; Talley, C; Schwartzberg, A; Braun, G; Moskovits, M; Reich, N; Huser, T

    2008-03-06

    We demonstrate the rapid optical characterization of large numbers of individual metal nanoparticles freely diffusing in colloidal solution by confocal laser spectroscopy. We find that hollow gold nanospheres and solid silver nanoparticles linked with a bifunctional ligand, both designed nanostructures, exhibit significantly higher monodispersity in their Rayleigh and Raman scattering response than randomly aggregated gold and silver nanoparticles. We show that measurements of rotational diffusion timescales allow sizing of particles significantly more reliably than can be obtained using translational diffusion timescales.

  18. Scattering Properties of Jovian Tropospheric Cloud Particles Inferred from Cassini/ISS: Mie Scattering Phase Function and Particle Size in South Tropical Zone III

    Science.gov (United States)

    Sato, T.; Satoh, T.; Kasaba, Y.

    2010-12-01

    The three distinct cloud layers were predicted by an equilibrium cloud condensation model (ECCM) of Jupiter. An ammonia ice cloud (NH3), an ammonia hydrosulfide cloud (NH4SH), and a water ice (H2O) cloud would be based at altitudes corresponding to pressures of about 0.7, 2.2 and 6 bars, respectively. However, there are significant gaps in our knowledge of the vertical cloud structure, despite the continuing effort by numerous ground-based, space-based, and in-situ observations and theory. Methane (CH4) is considered that its altitude distribution is globally uniform because it does not condense in Jovian atmosphere. Therefore, it is possible to derive the vertical cloud structure and the optical properties of clouds (i.e., optical thickness and single scattering albedo) by observing reflected sunlight in CH4 bands (727, 890 nm) and continuum in visible to near-infrared spectral ranges. Since we need to consider multiple scattering by clouds, it is essential to know scattering properties (e.g., scattering phase function) of clouds for determination of vertical cloud structure. However, we cannot derive those from ground-based and Earth-orbit observations because of the limitation of solar phase angle as viewed from the Earth. Then, most previous studies have used the scattering phase function deduced from the Pioneer 10/IPP data (blue: 440 nm, red: 640nm) [Tomasko et al., 1978]. There are two shortcomings in the Pioneer scattering phase function. One is that we have to use this scattering phase function at red as a substitute for analyses of imaging photometry using CH4 bands (center: 727 and 890 nm), although clouds should have wavelength dependency. The other is that the red pass band of IPP was so broad (595-720 nm) that this scattering phase function in red just show wavelength-averaged scattering properties of clouds. To provide a new reference scattering phase function with wavelength dependency, we have analyzed the Cassini/ISS data in BL1 (451 nm), CB1 (619

  19. Skeletal light-scattering accelerates bleaching response in reef-building corals.

    Science.gov (United States)

    Swain, Timothy D; DuBois, Emily; Gomes, Andrew; Stoyneva, Valentina P; Radosevich, Andrew J; Henss, Jillian; Wagner, Michelle E; Derbas, Justin; Grooms, Hannah W; Velazquez, Elizabeth M; Traub, Joshua; Kennedy, Brian J; Grigorescu, Arabela A; Westneat, Mark W; Sanborn, Kevin; Levine, Shoshana; Schick, Mark; Parsons, George; Biggs, Brendan C; Rogers, Jeremy D; Backman, Vadim; Marcelino, Luisa A

    2016-03-21

    At the forefront of ecosystems adversely affected by climate change, coral reefs are sensitive to anomalously high temperatures which disassociate (bleaching) photosynthetic symbionts (Symbiodinium) from coral hosts and cause increasingly frequent and severe mass mortality events. Susceptibility to bleaching and mortality is variable among corals, and is determined by unknown proportions of environmental history and the synergy of Symbiodinium- and coral-specific properties. Symbiodinium live within host tissues overlaying the coral skeleton, which increases light availability through multiple light-scattering, forming one of the most efficient biological collectors of solar radiation. Light-transport in the upper ~200 μm layer of corals skeletons (measured as 'microscopic' reduced-scattering coefficient, μ'(S,m)), has been identified as a determinant of excess light increase during bleaching and is therefore a potential determinant of the differential rate and severity of bleaching response among coral species. Here we experimentally demonstrate (in ten coral species) that, under thermal stress alone or combined thermal and light stress, low-μ'(S,m) corals bleach at higher rate and severity than high-μ'(S,m) corals and the Symbiodinium associated with low-μ'(S,m) corals experience twice the decrease in photochemical efficiency. We further modelled the light absorbed by Symbiodinium due to skeletal-scattering and show that the estimated skeleton-dependent light absorbed by Symbiodinium (per unit of photosynthetic pigment) and the temporal rate of increase in absorbed light during bleaching are several fold higher in low-μ'(S,m) corals. While symbionts associated with low-[Formula: see text] corals receive less total light from the skeleton, they experience a higher rate of light increase once bleaching is initiated and absorbing bodies are lost; further precipitating the bleaching response. Because microscopic skeletal light-scattering is a robust predictor

  20. On the calculation of x-ray scattering signals from pairwise radial distribution functions

    DEFF Research Database (Denmark)

    Dohn, Asmus Ougaard; Biasin, Elisa; Haldrup, Kristoffer

    2015-01-01

    We derive a formulation for evaluating (time-resolved) x-ray scattering signals of solvated chemical systems, based on pairwise radial distribution functions, with the aim of this formulation to accompany molecular dynamics simulations. The derivation is described in detail to eliminate any...... possible ambiguities, and the result includes a modification to the atom-type formulation which to our knowledge is previously unaccounted for. The formulation is numerically implemented and validated....

  1. Depolarized light scattering from prolate anisotropic particles: The influence of the particle shape on the field autocorrelation function.

    Science.gov (United States)

    Passow, Christopher; ten Hagen, Borge; Löwen, Hartmut; Wagner, Joachim

    2015-07-28

    We provide a theoretical analysis for the intermediate scattering function typically measured in depolarized dynamic light scattering experiments. We calculate the field autocorrelation function g1(VH)(Q,t) in dependence on the wave vector Q and the time t explicitly in a vertical-horizontal scattering geometry for differently shaped solids of revolution. The shape of prolate cylinders, spherocylinders, spindles, and double cones with variable aspect ratio is expanded in rotational invariants flm(r). By Fourier transform of these expansion coefficients, a formal multipole expansion of the scattering function is obtained, which is used to calculate the weighting coefficients appearing in the depolarized scattering function. In addition to translational and rotational diffusion, especially the translational-rotational coupling of shape-anisotropic objects is considered. From the short-time behavior of the intermediate scattering function, the first cumulants Γ(Q) are calculated. In a depolarized scattering experiment, they deviate from the simple proportionality to Q(2). The coefficients flm(Q) strongly depend on the geometry and aspect ratio of the particles. The time dependence, in addition, is governed by the translational and rotational diffusion tensors, which are calculated by means of bead models for differently shaped particles in dependence on their aspect ratio. Therefore, our analysis shows how details of the particle shape--beyond their aspect ratio--can be determined by a precise scattering experiment. This is of high relevance in understanding smart materials which involve suspensions of anisotropic colloidal particles.

  2. Analysis of MUSIC-type imaging functional for single, thin electromagnetic inhomogeneity in limited-view inverse scattering problem

    Science.gov (United States)

    Ahn, Chi Young; Jeon, Kiwan; Park, Won-Kwang

    2015-06-01

    This study analyzes the well-known MUltiple SIgnal Classification (MUSIC) algorithm to identify unknown support of thin penetrable electromagnetic inhomogeneity from scattered field data collected within the so-called multi-static response matrix in limited-view inverse scattering problems. The mathematical theories of MUSIC are partially discovered, e.g., in the full-view problem, for an unknown target of dielectric contrast or a perfectly conducting crack with the Dirichlet boundary condition (Transverse Magnetic-TM polarization) and so on. Hence, we perform further research to analyze the MUSIC-type imaging functional and to certify some well-known but theoretically unexplained phenomena. For this purpose, we establish a relationship between the MUSIC imaging functional and an infinite series of Bessel functions of integer order of the first kind. This relationship is based on the rigorous asymptotic expansion formula in the existence of a thin inhomogeneity with a smooth supporting curve. Various results of numerical simulation are presented in order to support the identified structure of MUSIC. Although a priori information of the target is needed, we suggest a least condition of range of incident and observation directions to apply MUSIC in the limited-view problem.

  3. Statistics of time delay and scattering correlation functions in chaotic systems. I. Random matrix theory

    Science.gov (United States)

    Novaes, Marcel

    2015-06-01

    We consider the statistics of time delay in a chaotic cavity having M open channels, in the absence of time-reversal invariance. In the random matrix theory approach, we compute the average value of polynomial functions of the time delay matrix Q = - iħS†dS/dE, where S is the scattering matrix. Our results do not assume M to be large. In a companion paper, we develop a semiclassical approximation to S-matrix correlation functions, from which the statistics of Q can also be derived. Together, these papers contribute to establishing the conjectured equivalence between the random matrix and the semiclassical approaches.

  4. Statistics of time delay and scattering correlation functions in chaotic systems. I. Random matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    Novaes, Marcel [Instituto de Física, Universidade Federal de Uberlândia, Ave. João Naves de Ávila, 2121, Uberlândia, MG 38408-100 (Brazil)

    2015-06-15

    We consider the statistics of time delay in a chaotic cavity having M open channels, in the absence of time-reversal invariance. In the random matrix theory approach, we compute the average value of polynomial functions of the time delay matrix Q = − iħS{sup †}dS/dE, where S is the scattering matrix. Our results do not assume M to be large. In a companion paper, we develop a semiclassical approximation to S-matrix correlation functions, from which the statistics of Q can also be derived. Together, these papers contribute to establishing the conjectured equivalence between the random matrix and the semiclassical approaches.

  5. Proton-proton elastic scattering excitation functions at intermediate energies: Cross sections and analyzing powers

    Energy Technology Data Exchange (ETDEWEB)

    Hinterberger, F.; Rohdjess, H.; Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Buesser, K.; Busch, M.; Colberg, T.; Diehl, O.; Dohrmann, F.; Engelhardt, H.P.; Eversheim, P.D.; Felden, O.; Gebel, R.; Glende, M.; Greiff, J.; Gross-Hardt, R.; Jahn, R.; Jonas, E.; Krause, H.; Langkau, R.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuk, T.; Meinerzhagen, A.; Naehle, O.; Prasuhn, D.; Rosendaal, D.; Rossen, P. von; Schirm, N.; Schulz-Rojahn, M.; Schwarz, V.; Scobel, W.; Trelle, H.J.; Weise, E.; Wellinghausen, A.; Woller, K.; Ziegler, R

    2000-01-31

    The EDDA experiment at the cooler synchrotron COSY measures proton-proton elastic scattering excitation functions in the momentum range 0.8 - 3.4 GeV/c. In phase 1 of the experiment, spin-averaged differential cross sections were measured continuously during acceleration with an internal polypropylene (CH{sub 2}) fiber target, taking particular care to monitor luminosity as a function of beam momentum. In phase 2, excitation functions of the analyzing power A{sub N} and the polarization correlation parameters A{sub NN}, A{sub SS} and A{sub SL} are measured using a polarized proton beam and a polarized atomic hydrogen beam target. The paper presents recent d{sigma}/d{omega} and A{sub N} data. The results provide excitation functions and angular distributions of high precision and internal consistency. No evidence for narrow structures was found. The data are compared to recent phase shift solutions.

  6. Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies: Cross Sections and Analyzing Powers

    Science.gov (United States)

    Hinterberger, F.; Rohdjeß, H.; Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Büßer, K.; Busch, M.; Colberg, T.; Diehl, O.; Dohrmann, F.; Engelhardt, H. P.; Eversheim, P. D.; Felden, O.; Gebel, R.; Glende, M.; Greiff, J.; Groß-Hardt, R.; Hinterberger, F.; Jahn, R.; Jonas, E.; Krause, H.; Langkau, R.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuk, T.; Meinerzhagen, A.; Nähle, O.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Schirm, N.; Schulz-Rojahn, M.; Schwarz, V.; Scobel, W.; Trelle, H. J.; Weise, E.; Wellinghausen, A.; Woller, K.; Ziegler, R.

    2000-01-01

    The EDDA experiment at the cooler synchrotron COSY measures proton-proton elastic scattering excitation functions in the momentum range 0.8 - 3.4 GeV/c. In phase 1 of the experiment, spin-averaged differential cross sections were measured continuously during acceleration with an internal polypropylene (CH2) fiber target, taking particular care to monitor luminosity as a function of beam momentum. In phase 2, excitation functions of the analyzing power AN and the polarization correlation parameters ANN, ASS and ASL are measured using a polarized proton beam and a polarized atomic hydrogen beam target. The paper presents recent dσ/dΩ and AN data. The results provide excitation functions and angular distributions of high precision and internal consistency. No evidence for narrow structures was found. The data are compared to recent phase shift solutions.

  7. Proton-proton elastic scattering excitation functions at intermediate energies: Cross sections and analyzing powers

    CERN Document Server

    Hinterberger, F; Altmeier, M; Bauer, F; Bisplinghoff, J; Büsser, K; Busch, M; Colberg, T; Diehl, O; Dohrmann, F; Engelhardt, H P; Eversheim, P D; Felden, O; Gebel, R; Glende, M; Greiff, J; Gross-Hardt, R; Hinterberger, F; Jahn, R; Jonas, E; Krause, H; Langkau, R; Lindemann, T; Lindlein, J; Maier, R; Maschuw, R; Mayer-Kuckuk, T; Meinerzhagen, A; Naehle, O; Prasuhn, D; Rohdjess, H; Rosendaal, D; Von Rossen, P; Schirm, N; Schulz-Rojahn, M; Schwarz, V; Scobel, W; Trelle, H J; Weise, E; Wellinghausen, A; Woller, K; Ziegler, R

    2000-01-01

    The EDDA experiment at the cooler synchrotron COSY measures proton-proton elastic scattering excitation functions in the momentum range 0.8 - 3.4 GeV/c. In phase 1 of the experiment, spin-averaged differential cross sections were measured continuously during acceleration with an internal polypropylene (CH sub 2) fiber target, taking particular care to monitor luminosity as a function of beam momentum. In phase 2, excitation functions of the analyzing power A sub N and the polarization correlation parameters A sub N sub N , A sub S sub S and A sub S sub L are measured using a polarized proton beam and a polarized atomic hydrogen beam target. The paper presents recent d sigma/d OMEGA and A sub N data. The results provide excitation functions and angular distributions of high precision and internal consistency. No evidence for narrow structures was found. The data are compared to recent phase shift solutions.

  8. Investigation of snow single scattering properties based on first order Legendre phase function

    Science.gov (United States)

    Eppanapelli, Lavan Kumar; Casselgren, Johan; Wåhlin, Johan; Sjödahl, Mikael

    2017-04-01

    Angularly resolved bidirectional reflectance measurements were modelled by approximating a first order Legendre expanded phase function to retrieve single scattering properties of snow. The measurements from 10 different snow types with known density and specific surface area (SSA) were investigated. A near infrared (NIR) spectrometer was used to measure reflected light above the snow surface over the hemisphere in the wavelength region of 900-1650 nm. A solver based on discrete ordinate radiative transfer (DISORT) model was used to retrieve the estimated Legendre coefficients of the phase function and a correlation between the coefficients and physical properties of different snow types is investigated. Results of this study suggest that the first two coefficients of the first order Legendre phase function provide sufficient information about the physical properties of snow where the latter captures the anisotropic behaviour of snow and the former provides a relative estimate of the single scattering albedo of snow. The coefficients of the first order phase function were compared with the experimental data and observed that both the coefficients are in good agreement with the experimental data. These findings suggest that our approach can be applied as a qualitative tool to investigate physical properties of snow and also to classify different snow types.

  9. Single-site Green function of the Dirac equation for full-potential electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kordt, Pascal

    2012-05-30

    I present an elaborated analytical examination of the Green function of an electron scattered at a single-site potential, for both the Schroedinger and the Dirac equation, followed by an efficient numerical solution, in both cases for potentials of arbitrary shape without an atomic sphere approximation. A numerically stable way to calculate the corresponding regular and irregular wave functions and the Green function is via the angular Lippmann-Schwinger integral equations. These are solved based on an expansion in Chebyshev polynomials and their recursion relations, allowing to rewrite the Lippmann-Schwinger equations into a system of algebraic linear equations. Gonzales et al. developed this method for the Schroedinger equation, where it gives a much higher accuracy compared to previous perturbation methods, with only modest increase in computational effort. In order to apply it to the Dirac equation, I developed relativistic Lippmann-Schwinger equations, based on a decomposition of the potential matrix into spin spherical harmonics, exploiting certain properties of this matrix. The resulting method was embedded into a Korringa-Kohn-Rostoker code for density functional calculations. As an example, the method is applied by calculating phase shifts and the Mott scattering of a tungsten impurity. (orig.)

  10. Dynamic Responsive Systems for Catalytic Function

    NARCIS (Netherlands)

    Vlatkovic, Matea; Collins, Beatrice S. L.; Feringa, Ben L.

    2016-01-01

    Responsive systems have recently gained much interest in the scientific community in attempts to mimic dynamic functions in biological systems. One of the fascinating potential applications of responsive systems lies in catalysis. Inspired by nature, novel responsive catalytic systems have been

  11. Confocal Light Absorption and Scattering Spectroscopic (CLASS) imaging: From cancer detection to sub-cellular function

    Science.gov (United States)

    Qiu, Le

    Light scattering spectroscopy (LSS), an optical technique that relates the spectroscopic properties of light elastically scattered by small particles to their size, refractive index and shape, has been recently successfully employed for sensing morphological and biochemical properties of epithelial tissues and cells in vivo. LSS does not require exogenous markers, is non-invasive, and, due to its multispectral nature, can sense biological structures well beyond the diffraction limit. All that makes LSS be a very good candidate to be used both in clinical medicine for in vivo detection of disease and in cell biology to monitor cell function on the organelle scale. Recently we developed two LSS-based imaging modalities: clinical Polarized LSS (PLSS) Endoscopic Technique for locating early pre-cancerous changes in GI tract and Confocal Light Absorption and Scattering Spectroscopic (CLASS) Microscopy for studying cells in vivo without exogenous markers. One important application of the clinical PLSS endoscopic instrument, a noncontact scanning imaging device compatible with the standard clinical endoscopes and capable of detecting dysplastic changes, is to serve as a guide for biopsy in Barrett's esophagus (BE). The instrument detects parallel and perpendicular components of the polarized light, backscattered from epithelial tissues, and determines characteristics of epithelial nuclei from the residual spectra. It also can find tissue oxygenation, hemoglobin content and other properties from the diffuse light component. By rapidly scanning esophagus the PLSS endoscopic instrument makes sure the entire BE portion is scanned and examined for the presence of dysplasia. CLASS microscopy, on the other hand, combines principles of light scattering spectroscopy (LSS) with confocal microscopy. Its main purpose is to image cells on organelle scale in vivo without the use of exogenous labels which may affect the cell function. The confocal geometry selects specific region and

  12. Dynamics of Different Functional Parts of Bacteriorhodopsin: H-2H Labeling and Neutron Scattering

    Science.gov (United States)

    Reat, Valerie; Patzelt, Heiko; Ferrand, Michel; Pfister, Claude; Oesterhelt, Dieter; Zaccai, Giuseppe

    1998-04-01

    We show that dynamics of specific amino acids within a protein can be characterized by neutron spectroscopy and hydrogen-deuterium labeling, and we present data on the motions of a selected set of groups within bacteriorhodopsin (BR), the retinal-based proton pump in the purple membrane of halophilic Archaea. Elastic incoherent neutron scattering experiments allow the definition of motions in the nano- to picosecond time scale and have revealed a dynamical transition from a harmonic to a softer, anharmonic atomic fluctuation regime in the global behavior of proteins. Biological activity in proteins is correlated with this transition, suggesting that flexibility is required for function. Elastic incoherent neutron scattering is dominated by H atom scattering, and to study the dynamics of a selected part of BR, fully deuterated purple membrane with BR containing H-retinal, H-tryptophan, and H-methionine was prepared biosynthetically in Halobacterium salinarum. These amino acids cluster in the functional center of the protein. In contrast to the protein globally, the thermal motions of the labeled atoms were found to be shielded from solvent melting effects at 260 K. Above this temperature, the labeled groups appear as more rigid than the rest of the protein, with a significantly smaller mean square amplitude of motion. These experimental results quantify the dynamical heterogeneity of BR (which meets the functional requirements of global flexibility), on the one hand, to allow large conformational changes in the molecule and of a more rigid region in the protein, on the other, to control stereo-specific selection of retinal conformations.

  13. Simulating the Daylight Performance of Complex Fenestration Systems Using Bidirectional Scattering Distribution Functions within Radiance

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Gregory; Mistrick, Ph.D., Richard; Lee, Eleanor; McNeil, Andrew; Jonsson, Ph.D., Jacob

    2011-01-21

    We describe two methods which rely on bidirectional scattering distribution functions (BSDFs) to model the daylighting performance of complex fenestration systems (CFS), enabling greater flexibility and accuracy in evaluating arbitrary assemblies of glazing, shading, and other optically-complex coplanar window systems. Two tools within Radiance enable a) efficient annual performance evaluations of CFS, and b) accurate renderings of CFS despite the loss of spatial resolution associated with low-resolution BSDF datasets for inhomogeneous systems. Validation, accuracy, and limitations of the methods are discussed.

  14. Coherent scattering function in the reptation model: analysis beyond asymptotic limits.

    Science.gov (United States)

    Schäfer, Lothar; Ebert, Ute; Baumgärtner, Artur

    2002-06-01

    We calculate the coherent dynamical scattering function S(c)(q,t;N) of a flexible chain of length N, diffusing through an ordered background of topological obstacles. As an instructive generalization, we also calculate the scattering function S(c)(q,t;M,N) for the central piece of length Mreptation model, we treat global creep, tube length fluctuations, and internal relaxation within a consistent and unified approach. Our theory concentrates on the universal aspects of reptational motion, and our results in all details show excellent agreement with our simulations of the Evans-Edwards model, provided we allow for a phenomenological prefactor which accounts for nonuniversal effects of the microstructure of the Monte Carlo chain, present for short times. Previous approaches to the coherent structure function can be analyzed as special limits of our theory. First, the effects of internal relaxation can be isolated by studying the limit N--> infinity, M fixed. The results do not support the model of a "Rouse chain in a tube." We trace this back to the nonequilibrium initial conditions of the latter model. Second, in the limit of long chains (M=N--> infinity ) and times large compared to the internal relaxation time (t/N(2)--> infinity ), our theory reproduces the results of the primitive chain model. This limiting form applies only to extremely long chains, and for chain lengths accessible in practice, effects of, e.g., tube length fluctuations are not negligible.

  15. Retrieving composition and sizes of oceanic particle subpopulations from the volume scattering function.

    Science.gov (United States)

    Zhang, Xiaodong; Twardowski, Michael; Lewis, Marlon

    2011-03-20

    For a particle population with known size, composition, structure, and shape distributions, its volume scattering function (VSF) can be estimated from first principles through a governing relationship, the Fredholm linear integral equation of the first kind. Inverting the Fredholm equation to derive the composition and size distribution of particles from measured VSFs remains challenging because 1) the solution depends on the kernel function, and 2) the kernel function needs to be constructed to avoid singularity. In this study, a thorough review of the earlier and current inversion techniques is provided. An inversion method based on nonnegative least squares is presented and evaluated using the VSFs measured by a prototype volume scattering meter at the LEO-15 site off the New Jersey coast. The kernel function was built by a compilation of individual subpopulations, each of which follows a lognormal size distribution and whose characteristic size and refractive index altogether cover the entire ranges of natural variability of potential marine particles of the region. Sensitivity analyses were conducted to ensure the kernel function being constructed is neither singular nor pathological. A total of 126 potential subpopulations were identified, among which 11 are common in more than half of the inversions and only five consistently present (>90% of measurements). These five subpopulations can be interpreted as small colloidal type particles of sizes around 0.02 μm, submicrometer detritus-type particles (n(r)=1.02, r(mode)=0.2 μm), two micrometer-sized subpopulations with one relatively soft (n(r)=1.04 and r(mode)=1.6 μm) and the other relatively refringent (n(r)=1.10 and r(mode)=3.2 μm), and bubbles of relatively large sizes (n(r)=0.75 and r(mode)=10 μm). Reconstructed PSDs feature a bimodal shape, with the smaller peak dominated by the colloidal subpopulations and the larger particles closely approximated by a power-law function. The Junge

  16. Low-energy shelf response in thin energy-dispersive X-ray detectors from Compton scattering of hard X-rays

    Science.gov (United States)

    Michel-Hart, N.; Elam, W. T.

    2017-08-01

    Silicon drift detectors have been successfully employed in both soft and hard X-ray spectroscopy. The response function to incident radiation at soft X-ray levels has been well studied and modeled, but less research has been published on response functions for these detectors to hard X-ray input spectra above 20 keV. When used with hard X-ray sources a significant low energy, non-peak response exists which can adversely affect detection limits for lighter elements in, for example, X-ray fluorescence spectroscopy. We present a numerical model that explains the non-peak response function of silicon drift detectors to hard X-rays based on incoherent Compton scattering within the detector volume. Experimental results are presented and numerically compared to model results.

  17. Bidirectional optical scattering facility

    Data.gov (United States)

    Federal Laboratory Consortium — Goniometric optical scatter instrument (GOSI)The bidirectional reflectance distribution function (BRDF) quantifies the angular distribution of light scattered from a...

  18. Spin response to backward (e,e{sup `}) scattering from heavy deformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nojarov, R. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Dingfelder, M. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik

    1996-01-27

    The M1 and E2 responses of spin 1{sup +} excitations to (e,e{sup `}) scattering from heavy deformed nuclei are studied in QRPA and DWBA on the example of {sup 158}Gd. The transverse response originates mainly from the magnetization currents. The transverse E2 dominates over the longitudinal C2 response for {theta}{>=}165 {sup circle}. The joint response of the whole spin-flip region (6-11 MeV) for {theta}{>=}165 {sup circle} is characterized by the M1 over E2 dominance for transferred momentum q{sub eff} < 0.6 fm{sup -1} (or incident electron energy E{sub i} < 40 MeV). Above these values the E2 response provides substantial contributions to the summed (e,e{sup `}) cross section. They are larger in the lower spin-flip region (6-8 MeV) due to the larger orbital (convection) contributions at lower excitation energy. (orig.).

  19. Moment expansion to the memory function for generalized Drude scattering rate

    Science.gov (United States)

    Bhalla, Pankaj; Das, Nabyendu; Singh, Navinder

    2016-05-01

    The memory function formalism is an important tool to evaluate the frequency dependent electronic conductivity. It is previously used within some approximations in the case of electrons interacting with various other degrees of freedom in metals with great success. However, one needs to go beyond those approximations as the interaction strengths become stronger. In this work, we propose a systematic expansion of the memory function involving its various moments. We calculate the higher order contribution to the generalized Drude scattering rate in case of electron-impurity interactions. Further we compare our results with the results from previously studied lowest order calculations. We find larger contributions from the higher moments in the low frequency regime and also in the case of larger interaction strength.

  20. Moment expansion to the memory function for generalized Drude scattering rate

    Energy Technology Data Exchange (ETDEWEB)

    Bhalla, Pankaj, E-mail: pankajbhalla66@gmail.com [Physical Research Laboratory, Navrangpura, Ahmedabad 380009 (India); Indian Institute of Technology Gandhinagar, 382355 (India); Das, Nabyendu; Singh, Navinder [Physical Research Laboratory, Navrangpura, Ahmedabad 380009 (India)

    2016-05-20

    The memory function formalism is an important tool to evaluate the frequency dependent electronic conductivity. It is previously used within some approximations in the case of electrons interacting with various other degrees of freedom in metals with great success. However, one needs to go beyond those approximations as the interaction strengths become stronger. In this work, we propose a systematic expansion of the memory function involving its various moments. We calculate the higher order contribution to the generalized Drude scattering rate in case of electron–impurity interactions. Further we compare our results with the results from previously studied lowest order calculations. We find larger contributions from the higher moments in the low frequency regime and also in the case of larger interaction strength.

  1. Elastodynamics response of Green's function and influence function ...

    African Journals Online (AJOL)

    The article reports on a methodology to synthesize the response of Green's function and influence function in fluid saturated incompressible porous half space. As an application, the disturbance due to concentrated and distributed loads in normal and tangential direction is investigated by employing the Laplace and Fourier ...

  2. Evaluation of polarization rotation in the scattering responses from individual semiconducting oxide nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Daniel S.; Singh, Manpreet; Zhou, Hebing; Milchak, Marissa; Monahan, Brian; Hahm, Jong-in, E-mail: jh583@georgetown.edu [Department of Chemistry, Georgetown University, 37" t" h & O Sts. NW., Washington, DC 20057 (United States)

    2016-04-15

    We investigate the interaction of visible light with the solid matters of semiconducting oxide nanorods (NRs) of zinc oxide (ZnO), indium tin oxide (ITO), and zinc tin oxide (ZTO) at the single nanomaterial level. We subsequently identify an intriguing, material-dependent phenomenon of optical rotation in the electric field oscillation direction of the scattered light by systematically controlling the wavelength and polarization direction of the incident light, the NR tilt angle, and the analyzer angle. This polarization rotation effect in the scattered light is repeatedly observed from the chemically pure and highly crystalline ZnO NRs, but absent on the chemically doped NR variants of ITO and ZTO under all measurement circumstances. We further elucidate that the phenomenon of polarization rotation detected from single ZnO NRs is affected by the NR tilt angle, while the phenomenon itself occurs irrespective of the wavelength and incident polarization direction of the visible light. Combined with the widespread optical and optoelectronic use of the semiconducting oxide nanomaterials, these efforts may provide much warranted fundamental bases to tailor material-specific, single nanomaterial-driven, optically modulating functionalities which, in turn, can be beneficial for the realization of high-performance integrated photonic circuits and miniaturized bio-optical sensing devices.

  3. Orbital response to backward (e,e{sup `}) scattering at low and high excitation energies

    Energy Technology Data Exchange (ETDEWEB)

    Nojarov, R. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Faessler, A. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Dingfelder, M. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik

    1996-04-15

    The response of orbital excitations with K{sup {pi}}=1{sup +} in heavy deformed nuclei to backward (e,e`) scattering is studied in RPA on the example of {sup 154}Sm. The summed M1 and E2 cross sections are of comparable magnitude over wide ranges of transferred momenta: 0.9responses can be separated at backward angles only for small q, where the M1 response dominates at low energy and the E2 response in the high-energy region. The transition densities of the single strongest RPA states from the two energy regions are similar to that of the scissors state, apart from their smaller amplitudes. The spin M1 responses are similar at low and high energy and dominant for high q. The orbital M1 response is dominant up to high q-values at low energy and only for small q at high energy. The electric response of the low RPA state (mainly C2) is suppressed at a full backward angle, while it persists at high energy for {theta}{>=}165 {sup circle} due to its dominant transverse E2 component. The E2 strength below 9 MeV and between 13 and 17 MeV belongs neither to the isoscalar nor to the isovector giant resonances. (orig.).

  4. Numerical Green's functions in optical potential calculations for positron scattering from argon and neon

    Science.gov (United States)

    Bartschat, K.; Mceachran, R. P.; Stauffer, A. D.

    1990-01-01

    An optical potential method was applied to the calculation of positron scattering from the noble gases in order to determine the effect of open excitation channels on the shape of differential scattering cross sections.

  5. Understanding charge transfer of Li+ and Na+ ions scattered from metal surfaces with high work function

    Science.gov (United States)

    Chen, Lin; Wu, Wen-Bin; Liu, Pin-Yang; Xiao, Yun-Qing; Li, Guo-Peng; Liu, Yi-Ran; Jiang, Hao-Yu; Guo, Yan-Ling; Chen, Xi-Meng

    2016-08-01

    For Li+ and Na+ ions scattered from high work function metal surfaces, efficient neutralization is observed, and it cannot be explained by the conventional free electron model. In order to explain these experimental data, we investigate the velocity-dependent neutral fraction with the modified Brako-Newns (BN) model. The calculated results are in agreement with the experimental data. We find that the parallel velocity effect plays an important role in neutralizing the Li+ and Na+ ions for large angle scattering. The nonmonotonic velocity behavior of neutral fraction is strongly related to the distance-dependent coupling strength between the atomic level and metal states. Project supported by the National Natural Science Foundation of China (Grant Nos. 11405078 and 11474140), the Fundamental Research Funds for the Central Universities, China (Grant Nos. lzujbky-2014-169 and lzujbky-2015-244), the Project sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, the State Education Ministry, and the National Students’ Innovation and Entrepreneurship Training Program (Grant Nos. 201410730069 and 201510730078).

  6. Grand canonical ensemble, multi-particle wave functions and scattering data

    CERN Document Server

    Bruckmann, Falk; Kloiber, Thomas; Sulejmanpasic, Tin

    2015-01-01

    We show that information about scattering data of a quantum field theory can be obtained from studying the system at finite density and low temperatures. In particular we consider models formulated on the lattice which can be exactly dualized to theories of conserved charge fluxes on lattice links. Apart from eliminating the complex action problem at nonzero chemical potential mu, these dualizations allow for a particle world line interpretation of the dual fluxes from which one can extract data about the 2-particle wave function. As an example we perform dual Monte Carlo simulations of the 2-dimensional O(3) model at nonzero mu and finite volume, whose non-perturbative spectrum consists of a massive triplet of particles. At nonzero mu particles are induced in the system, which at sufficiently low temperature give rise to sectors of fixed particle number. We show that the scattering phase shifts can be obtained either from the critical chemical potential values separating the sectors or directly from the wave...

  7. Auxiliary fermion approach to the resonant inelastic x-ray scattering response in an underdoped cuprate

    Science.gov (United States)

    Shi, Yifei; James, Andrew J. A.; Demler, Eugene; Klich, Israel

    2017-10-01

    We describe a method for calculating the resonant inelastic x-ray scattering (RIXS) response—including the dynamics of the transient core hole—of many-body systems with nontrivial gap structure encoded in their single particle Green's function. Our approach introduces auxiliary fermions in order to obtain a form amenable to the determinant method of Benjamin et al., [Phys. Rev. Lett. 112, 247002 (2014), 10.1103/PhysRevLett.112.247002], and is applicable to systems where interactions are most strongly felt through a renormalization of the single particle propagator. As a test case we consider the Yang-Rice-Zhang ansatz for cuprate phenomena in the underdoped "pseudogap" regime, which remains a popular tool for interpreting the results of experimental probes. We show that taking the core hole dynamics into account for a system described by this ansatz pushes the RIXS peaks towards higher energy transfer, improving agreement with experiments.

  8. Nanoparticle-Functionalized Porous Polymer Monolith Detection Elements for Surface-Enhanced Raman Scattering

    Science.gov (United States)

    Liu, Jikun; White, Ian; DeVoe, Don L.

    2011-01-01

    The use of porous polymer monoliths functionalized with silver nanoparticles is introduced in this work for high-sensitivity surface-enhanced Raman scattering (SERS) detection. Preparation of the SERS detection elements is a simple process comprising the synthesis of a discrete polymer monolith section within a silica capillary, followed by physically trapping silver nanoparticle aggregates within the monolith matrix. A SERS detection limit of 220 fmol for Rhodamine 6G (R6G) is demonstrated, with excellent signal stability over a 24 h period. The capability of the SERS-active monolith for label-free detection of biomolecules was demonstrated by measurements of bradykinin and cyctochrome c. The SERS-active monoliths can be readily integrated into miniaturized micro-total-analysis systems for on-line and label-free detection for a variety of biosensing, bioanalytical, and biomedical applications. PMID:21322579

  9. A Practical Framework for Sharing and Rendering Real-World Bidirectional Scattering Distribution Functions

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Greg [Anywhere Software, Albany, CA (United States); Kurt, Murat [International Computer Institute, Ege University (Turkey); Bonneel, Nicolas [Harvard Univ., Cambridge, MA (United States)

    2012-09-30

    The utilization of real-world materials has been hindered by a lack of standards for sharing and interpreting measured data. This paper presents an XML representation and an Open Source C library to support bidirectional scattering distribution functions (BSDFs) in data-driven lighting simulation and rendering applications.The library provides for the efficient representation, query, and Monte Carlo sampling of arbitrary BSDFs in amodel-free framework. Currently, we support two BSDF data representations: one using a fixed subdivision of thehemisphere, and one with adaptive density. The fixed type has advantages for certain matrix operations, while theadaptive type can more accurately represent highly peaked data. We discuss advanced methods for data-drivenBSDF rendering for both types, including the proxy of detailed geometry to enhance appearance and accuracy.We also present an advanced interpolation method to reduce measured data into these standard representations.We end with our plan for future extensions and sharing of BSDF data.

  10. Disorder effects on the static scattering function of star branched polymers

    Directory of Open Access Journals (Sweden)

    V. Blavatska

    2012-10-01

    Full Text Available We present an analysis of the impact of structural disorder on the static scattering function of f-armed star branched polymers in d dimensions. To this end, we consider the model of a star polymer immersed in a good solvent in the presence of structural defects, correlated at large distances r according to a power law ~r-a. In particular, we are interested in the ratio g(f of the radii of gyration of star and linear polymers of the same molecular weight, which is a universal experimentally measurable quantity. We apply a direct polymer renormalization approach and evaluate the results within the double ϵ = 4 - d, δ = 4 - a-expansion. We find an increase of g(f with an increasing δ. Therefore, an increase of disorder correlations leads to an increase of the size measure of a star relative to linear polymers of the same molecular weight.

  11. Two Comments to Utilization of Structure Function Approach in Deep Inelastic Scattering Experiments

    CERN Document Server

    Kuraev, E A; Ilichev, A S

    2002-01-01

    The "returning to resonance" mechanism can be used to obtain the simple procedure of taking radiative corrections (RC) to deep inelastic scattering (DIS) cross sections into account in the framework of Drell-Yan picture. Iteration procedure is proposed. Kinematical region y\\to 1 can be described in the framework of Drell-Yan picture using the structure function approach. The large RC in the lowest order reflect the Sudakov form factor suppression, which can be taken into account in all orders of perturbation theory. Based on explicit calculation in two lowest orders of perturbation theory we construct the cross section in y\\to 1 region obeying renormalization group equations and including the Sudakov-like form factor suppression.

  12. Pair distribution functions of amorphous organic thin films from synchrotron X-ray scattering in transmission mode

    Directory of Open Access Journals (Sweden)

    Chenyang Shi

    2017-09-01

    Full Text Available Using high-brilliance high-energy synchrotron X-ray radiation, for the first time the total scattering of a thin organic glass film deposited on a strongly scattering inorganic substrate has been measured in transmission mode. The organic thin film was composed of the weakly scattering pharmaceutical substance indomethacin in the amorphous state. The film was 130 µm thick atop a borosilicate glass substrate of equal thickness. The atomic pair distribution function derived from the thin-film measurement is in excellent agreement with that from bulk measurements. This ability to measure the total scattering of amorphous organic thin films in transmission will enable accurate in situ structural studies for a wide range of materials.

  13. Pair distribution functions of amorphous organic thin films from synchrotron X-ray scattering in transmission mode.

    Science.gov (United States)

    Shi, Chenyang; Teerakapibal, Rattavut; Yu, Lian; Zhang, Geoff G Z

    2017-09-01

    Using high-brilliance high-energy synchrotron X-ray radiation, for the first time the total scattering of a thin organic glass film deposited on a strongly scattering inorganic substrate has been measured in transmission mode. The organic thin film was composed of the weakly scattering pharmaceutical substance indomethacin in the amorphous state. The film was 130 µm thick atop a borosilicate glass substrate of equal thickness. The atomic pair distribution function derived from the thin-film measurement is in excellent agreement with that from bulk measurements. This ability to measure the total scattering of amorphous organic thin films in transmission will enable accurate in situ structural studies for a wide range of materials.

  14. QCD Precision Measurements and Structure Function Extraction at a High Statistics, High Energy Neutrino Scattering Experiment: NuSOnG

    Energy Technology Data Exchange (ETDEWEB)

    Adams, T.; /Florida State U.; Batra, P.; /Columbia U.; Bugel, Leonard G.; /Columbia U.; Camilleri, Leslie Loris; /Columbia U.; Conrad, Janet Marie; /MIT; de Gouvea, A.; /Northwestern U.; Fisher, Peter H.; /MIT; Formaggio, Joseph Angelo; /MIT; Jenkins, J.; /Northwestern U.; Karagiorgi, Georgia S.; /MIT; Kobilarcik, T.R.; /Fermilab /Texas U.

    2009-06-01

    We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDFs). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parameterized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of 'Beyond the Standard Model' physics.

  15. QCD Precision Measurements and Structure Function Extraction at a High Statistics, High Energy Neutrino Scattering Experiment:. NuSOnG

    Science.gov (United States)

    Adams, T.; Batra, P.; Bugel, L.; Camilleri, L.; Conrad, J. M.; de Gouvêa, A.; Fisher, P. H.; Formaggio, J. A.; Jenkins, J.; Karagiorgi, G.; Kobilarcik, T. R.; Kopp, S.; Kyle, G.; Loinaz, W. A.; Mason, D. A.; Milner, R.; Moore, R.; Morfín, J. G.; Nakamura, M.; Naples, D.; Nienaber, P.; Olness, F. I.; Owens, J. F.; Pate, S. F.; Pronin, A.; Seligman, W. G.; Shaevitz, M. H.; Schellman, H.; Schienbein, I.; Syphers, M. J.; Tait, T. M. P.; Takeuchi, T.; Tan, C. Y.; van de Water, R. G.; Yamamoto, R. K.; Yu, J. Y.

    We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDF's). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parametrized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of "Beyond the Standard Model" physics.

  16. A Concept for Measuring Electron Distribution Functions Using Collective Thomson Scattering

    Science.gov (United States)

    Milder, A. L.; Froula, D. H.

    2017-10-01

    A.B. Langdon proposed that stable non-Maxwellian distribution functions are realized in coronal inertial confinement fusion plasmas via inverse bremsstrahlung heating. For Zvosc2 Zvosc2 vth2 > 1 , vth2 > 1 , the inverse bremsstrahlung heating rate is sufficiently fast to compete with electron-electron collisions. This process preferentially heats the subthermal electrons leading to super-Gaussian distribution functions. A method to identify the super-Gaussian order of the distribution functions in these plasmas using collective Thomson scattering will be proposed. By measuring the collective Thomson spectra over a range of angles the density, temperature and super-Gaussian order can be determined. This is accomplished by fitting non-Maxwellian distribution data with a super-Gaussian model; in order to match the density and electron temperature to within 10%, the super-Gaussian order must be varied. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  17. A Biomedical Surface Enhanced Raman Scattering Substrate: Functionalized Three-Dimensional Porous Membrane Decorated with Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Li Yuan

    2015-01-01

    Full Text Available We fabricated a simple, cheap, and functional surface enhanced Raman scattering substrate for biomedical application. Hot spots between two close silver nanoparticles distributed in the skeleton of a three-dimensional porous membrane, especially in the pores, were formed. The dual poles of micropores in the membrane were discussed. The pores could protect the silver nanoparticles in the pores from being oxidized, which makes the membrane effective for a longer period of time. In addition, Staphylococcus aureus cells could be trapped by the micropores and then the Raman signal became stronger, indicating that the functional surface enhanced Raman scattering substrate is reliable.

  18. Dynamic Responsive Systems for Catalytic Function.

    Science.gov (United States)

    Vlatković, Matea; Collins, Beatrice S L; Feringa, Ben L

    2016-11-21

    Responsive systems have recently gained much interest in the scientific community in attempts to mimic dynamic functions in biological systems. One of the fascinating potential applications of responsive systems lies in catalysis. Inspired by nature, novel responsive catalytic systems have been built that show analogy with allosteric regulation of enzymes. The design of responsive catalytic systems allows control of catalytic activity and selectivity. In this Review, advances in the field over the last four decades are discussed and a comparison is made amongst the dynamic responsive systems based on the principles underlying their catalytic mechanisms. The catalyst systems are sorted according to the triggers used to achieve control of the catalytic activity and the distinct catalytic reactions illustrated. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Autoimmune Response Confers Decreased Cardiac Function in ...

    African Journals Online (AJOL)

    Purpose: To explore the effect of autoimmune response on the decreased cardiac function in patients with rheumatic mitral lesion following valve replacement. Methods: In this case-controlled study, 29 patients who had undergone valve replacement as a result of mitral lesion were enrolled (mean age = 48.7 years). Twenty ...

  20. Generalized Drude scattering rate from the memory function formalism: an independent verification of the Sharapov-Carbotte result

    Science.gov (United States)

    Bhalla, Pankaj; Singh, Navinder

    2016-02-01

    An explicit perturbative computation of the Mori's memory function was performed by Götze and Wölfle (GW) to calculate generalized Drude scattering (GDS) rate for the case of electron-impurity and electron-phonon scattering in metals by assuming constant electronic density of states at the Fermi energy. In the present investigation, we go beyond this assumption and extend the GW formalism to the case in which there is a gap around the Fermi surface in electron density of states. The resulting GDS is compared with a recent one by Sharapov and Carbotte (SC) obtained through a different route. We find good agreement between the two at finite frequencies. However, we find discrepancies in the dc scattering rate. These are due to a crucial assumption made in SC namely ω ≫ | Σ(ɛ + ω) - Σ∗(ɛ) |. No such high frequency assumption is made in the memory function based technique.

  1. 15-digit accuracy calculations of Chandrasekhar's H-function for isotropic scattering by means of the double exponential formula

    Science.gov (United States)

    Kawabata, Kiyoshi

    2016-12-01

    This work shows that it is possible to calculate numerical values of the Chandrasekhar H-function for isotropic scattering at least with 15-digit accuracy by making use of the double exponential formula (DE-formula) of Takahashi and Mori (Publ. RIMS, Kyoto Univ. 9:721, 1974) instead of the Gauss-Legendre quadrature employed in the numerical scheme of Kawabata and Limaye (Astrophys. Space Sci. 332:365, 2011) and simultaneously taking a precautionary measure to minimize the effects due to loss of significant digits particularly in the cases of near-conservative scattering and/or errors involved in returned values of library functions supplied by compilers in use. The results of our calculations are presented for 18 selected values of single scattering albedo π0 and 22 values of an angular variable μ, the cosine of zenith angle θ specifying the direction of radiation incident on or emergent from semi-infinite media.

  2. A single-sided homogeneous Green's function representation for holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval

    NARCIS (Netherlands)

    Wapenaar, C.P.A.; Thorbecke, J.W.; van der Neut, J.R.

    2016-01-01

    Green's theorem plays a fundamental role in a diverse range of wavefield imaging applications, such as holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval. In many of those applications, the homogeneous Green's function (i.e. the Green's

  3. Multilevel Green's function interpolation method for scattering from composite metallic and dielectric objects.

    Science.gov (United States)

    Shi, Yan; Wang, Hao Gang; Li, Long; Chan, Chi Hou

    2008-10-01

    A multilevel Green's function interpolation method based on two kinds of multilevel partitioning schemes--the quasi-2D and the hybrid partitioning scheme--is proposed for analyzing electromagnetic scattering from objects comprising both conducting and dielectric parts. The problem is formulated using the surface integral equation for homogeneous dielectric and conducting bodies. A quasi-2D multilevel partitioning scheme is devised to improve the efficiency of the Green's function interpolation. In contrast to previous multilevel partitioning schemes, noncubic groups are introduced to discretize the whole EM structure in this quasi-2D multilevel partitioning scheme. Based on the detailed analysis of the dimension of the group in this partitioning scheme, a hybrid quasi-2D/3D multilevel partitioning scheme is proposed to effectively handle objects with fine local structures. Selection criteria for some key parameters relating to the interpolation technique are given. The proposed algorithm is ideal for the solution of problems involving objects such as missiles, microstrip antenna arrays, photonic bandgap structures, etc. Numerical examples are presented to show that CPU time is between O(N) and O(N log N) while the computer memory requirement is O(N).

  4. Surface enhanced Raman scattering activity of dual-functional Fe3O4/Au composites

    Science.gov (United States)

    Wang, Li-Ping; Huang, Yu-Bin; Lai, Ying-Huang

    2018-03-01

    There is a high demand for multifunctional materials that can integrate sample collection and sensing. In this study, magnetic Fe3O4 clusters were fabricated using a simple solvent-thermal method. The effect of the reductant (sodium citrate, SC) on the structure and morphology of Fe3O4 was examined by the variation in the reagent amount. The resulting Fe3O4 clusters were functionalized with 3-aminopropyltriethoxysilane (APTES) to anchor Au nanoparticles to its surface. The fabricated composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and a superconducting quantum interference device (SQUID) magnetometer. Dual-functional Fe3O4/Au clusters were obtained, effectively combining magnetic and plasmonic optical properties. The magnetic Fe3O4 cluster cores permitted the adsorption of the probe molecules, while sample concentration and collection were carried out under an external magnetic field. In addition, 4-nitrothiophenol (4-NTP) was chosen as the probe molecule to examine the analyte concentration ability and surface-enhanced Raman scattering (SERS) activity of the Fe3O4/Au composites. The results indicated that the Fe3O4/Au clusters exhibit a prominent SERS effect. The best 4-NTP detection limit obtained was 1 × 10-8 M, with a corresponding SERS analytical enhancement factor (AEF) exceeding 2 × 105.

  5. Multiple Volume Scattering in Random Media and Periodic Structures with Applications in Microwave Remote Sensing and Wave Functional Materials

    Science.gov (United States)

    Tan, Shurun

    The objective of my research is two-fold: to study wave scattering phenomena in dense volumetric random media and in periodic wave functional materials. For the first part, the goal is to use the microwave remote sensing technique to monitor water resources and global climate change. Towards this goal, I study the microwave scattering behavior of snow and ice sheet. For snowpack scattering, I have extended the traditional dense media radiative transfer (DMRT) approach to include cyclical corrections that give rise to backscattering enhancements, enabling the theory to model combined active and passive observations of snowpack using the same set of physical parameters. Besides DMRT, a fully coherent approach is also developed by solving Maxwell's equations directly over the entire snowpack including a bottom half space. This revolutionary new approach produces consistent scattering and emission results, and demonstrates backscattering enhancements and coherent layer effects. The birefringence in anisotropic snow layers is also analyzed by numerically solving Maxwell's equation directly. The effects of rapid density fluctuations in polar ice sheet emission in the 0.5˜2.0 GHz spectrum are examined using both fully coherent and partially coherent layered media emission theories that agree with each other and distinct from incoherent approaches. For the second part, the goal is to develop integral equation based methods to solve wave scattering in periodic structures such as photonic crystals and metamaterials that can be used for broadband simulations. Set upon the concept of modal expansion of the periodic Green's function, we have developed the method of broadband Green's function with low wavenumber extraction (BBGFL), where a low wavenumber component is extracted and results a non-singular and fast-converging remaining part with simple wavenumber dependence. We've applied the technique to simulate band diagrams and modal solutions of periodic structures, and to

  6. SATURN’S G AND D RINGS PROVIDE NEARLY COMPLETE MEASURED SCATTERING PHASE FUNCTIONS OF NEARBY DEBRIS DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Hedman, Matthew M. [Physics Department, University of Idaho, 875 Perimeter Drive, MS 0903, Moscow, ID 83844-0903 (United States); Stark, Christopher C., E-mail: mhedman@uidaho.edu, E-mail: cstark@stsci.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2015-09-20

    The appearance of debris disks around distant stars depends upon the scattering/phase function (SPF) of the material in the disk. However, characterizing the SPFs of these extrasolar debris disks is challenging because only a limited range of scattering angles are visible to Earth-based observers. By contrast, Saturn’s tenuous rings can be observed over a much broader range of geometries, so their SPFs can be much better constrained. Since these rings are composed of small particles released from the surfaces of larger bodies, they are reasonable analogs to debris disks and so their SPFs can provide insights into the plausible scattering properties of debris disks. This work examines two of Saturn’s dusty rings: the G ring (at 167,500 km from Saturn’s center) and the D68 ringlet (at 67,600 km). Using data from the cameras on board the Cassini spacecraft, we are able to estimate the rings’ brightnesses at scattering angles ranging from 170° to 0.°5. We find that both of the rings exhibit extremely strong forward-scattering peaks, but for scattering angles above 60° their brightnesses are nearly constant. These SPFs can be well approximated by a linear combination of three Henyey–Greenstein functions, and are roughly consistent with the SPFs of irregular particles from laboratory measurements. Comparing these data to Fraunhofer and Mie models highlights several challenges involved in extracting information about particle compositions and size distributions from SPFs alone. The SPFs of these rings also indicate that the degree of forward scattering in debris disks may be greatly underestimated.

  7. Spectrum response and analysis of 77 GHz band collective Thomson scattering diagnostic for bulk and fast ions in LHD plasmas

    DEFF Research Database (Denmark)

    Nishiura, M.; Kubo, S.; Tanaka, K.

    2014-01-01

    A collective Thomson scattering (CTS) diagnostic was developed and used to measure the bulk and fast ions originating from 180 keV neutral beams in the Large Helical Device (LHD). Electromagnetic waves from a gyrotron at 77 GHz with 1 MW power output function as both the probe and electron cyclot...

  8. Amplification of resonant Rayleigh light scattering response using immunogold colloids for detection of lysozyme.

    Science.gov (United States)

    Truong, Phuoc Long; Choi, Seung Phill; Sim, Sang Jun

    2013-10-25

    A strategy for attomolar-level detection of small molecule-size proteins is reported based on Rayleigh light scattering spectroscopy of individual nanoplasmonic aptasensors by exploiting the outstanding characteristics of gold colloids to amplify the nontransparent resonant signal at ultralow analyte concentrations. The fabrication method utilizes thiol-mediated adsorption of a DNA aptamer on the immobilized Au nanoparticle surface, the interfacial binding characteristics of the aptamer with its target molecules, and the antibody-antigen interaction through plasmonic resonance coupling of the Au nanoparticles. Using lysozyme as a model analyte for disease detection, the detection limit of the aptasensor is ∼7 × 10(3) aM, corresponding to the LSPR λmax shift of ∼2.25 nm. Up to a 380% increase in the localized resonant λmax shift is demonstrated upon antibody binding to the analyte compared to the primary response during signal amplification using immunogold colloids. This enhancement leads to a limit of detection of ∼7 aM, which is an improvement of three orders of magnitude. The results demonstrate substantial promise for developing coupled plasmonic nanostructures for ultrasensitive detection of various biological and chemical analytes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Characterization of phthalocyanine functionalized quantum dots by dynamic light scattering, laser Doppler, and capillary electrophoresis.

    Science.gov (United States)

    Ramírez-García, Gonzalo; Oluwole, David O; Nxele, Siphesihle Robin; d'Orlyé, Fanny; Nyokong, Tebello; Bedioui, Fethi; Varenne, Anne

    2017-02-01

    In this work, we characterized different phtalocyanine-capped core/shell/shell quantum dots (QDs) in terms of stability, ζ-potential, and size at various pH and ionic strengths, by means of capillary electrophoresis (CE), and compared these results to the ones obtained by laser Doppler electrophoresis (LDE) and dynamic light scattering (DLS). The effect of the phthalocyanine metallic center (Zn, Al, or In), the number (one or four), and nature of substituents (carboxyphenoxy- or sulfonated-) of functionalization on the phthalocyanine physicochemical properties were evaluated. Whereas QDs capped with zinc mono-carboxyphenoxy-phtalocyanine (ZnMCPPc-QDs) remained aggregated in the whole analyzed pH range, even at low ionic strength, QDs capped with zinc tetracarboxyphenoxy phtalocyanine (ZnTPPc-QDs) were easily dispersed in buffers at pH equal to or higher than 7.4. QDs capped with aluminum tetrasulfonated phthalocyanine (AlTSPPc-QDs) and indium tetracarboxyphenoxy phthalocyanines (InTCPPc-QDs) were stable in aqueous suspension only at pH higher than 9.0 due to the presence of functional groups bound to the metallic center of the phthalocyanine. The ζ-potential values determined by CE for all the samples decreased when ionic strength increased, being well correlated with the aggregation of the nanoconjugates at elevated salt concentrations. The use of electrokinetic methodologies has provided insights into the colloidal stability of the photosensitizer-functionalized QDs in physiological relevant solutions and thereby, its usefulness for improving their design and applications for photodynamic therapy. Graphical Abstract Schematic illustration of the phthalocyanine capped QDs nanoconjugates and the capillary electrophoresis methods applied for size and ζ-potential characterization.

  10. Measurement of the Proton Structure Function $F_{2}$ at low $Q^{2}$ in QED Compton Scattering at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brisson, V.; Broker, H.-B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Koblitz, B.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kroseberg, J.; Kuckens, J.; Kuhr, T.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morozov, I.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Ossoskov, G.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Raicevic, N.; Ratiani, Z.; Reimer, P.; Reisert, B.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.-P.; Schleper, P.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Winter, G.-G.; Wissing, Ch.; Woehrling, E.-E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2004-01-01

    The proton structure function F_2(x,Q^2) is measured in inelastic QED Compton scattering using data collected with the H1 detector at HERA. QED Compton events are used to access the kinematic range of very low virtualities of the exchanged photon, Q^2, down to 0.5 GeV^2, and Bjorken x up to \\sim 0.06, a region which has not been covered previously by inclusive measurements at HERA. The results are in agreement with the measurements from fixed target lepton-nucleon scattering experiments.

  11. A Functional Model of the Aesthetic Response

    Directory of Open Access Journals (Sweden)

    Daniel Conrad

    2010-01-01

    Full Text Available In a process of somatic evolution, the brain semi-randomly generates initially-unstable neural circuits that are selectively stabilized if they succeed in making sense out of raw sensory input. The human aesthetic response serves the function of stabilizing the circuits that successfully mediate perception and interpretation, making those faculties more agile, conferring selective advantage. It is triggered by structures in art and nature that provoke the making of sense. Art is deliberate human action aimed at triggering the aesthetic response in others; thus, if successful, it serves the same function of making perception and interpretation more agile. These few principles initiate a cascade of emergent phenomena which account for many observed qualities of aesthetics, including universality and idiosyncrasy of taste, the relevance of artists’ intentions, the virtues of openness and resonance, the dysfunction of formulaic art, and the fact that methods of art correspond to modes of perceptual transformation.

  12. Exact and explicit expression of the atomic pair distribution function as obtained from X-ray total scattering experiments

    OpenAIRE

    Masson, Olivier; Thomas, Philippe

    2013-01-01

    International audience; The atomic pair distribution function (PDF) as obtained from X-ray or neutron total scattering experiments has proved to be powerful in obtaining valuable structural information for many complex functional materials, be they amorphous or crystalline. In the case of measurements made with X-rays and for samples containing more than one kind of atom, the usefulness of the PDF is, however, somewhat hampered because of the lack of an exact and simple expression relating it...

  13. Ant functional responses along environmental gradients.

    Science.gov (United States)

    Arnan, Xavier; Cerdá, Xim; Retana, Javier

    2014-11-01

    Understanding species distributions and diversity gradients is a central challenge in ecology and requires prior knowledge of the functional traits mediating species' survival under particular environmental conditions. While the functional ecology of plants has been reasonably well explored, much less is known about that of animals. Ants are among the most diverse, abundant and ecologically significant organisms on earth, and they perform a great variety of ecological functions. In this study, we analyse how the functional species traits present in ant communities vary along broad gradients in climate, productivity and vegetation type in the south-western Mediterranean. To this end, we compiled one of the largest animal databases to date: it contains information on 211 local ant communities (including eight climate variables, productivity, and vegetation type) and 124 ant species, for which 10 functional traits are described. We used traits that characterize different dimensions of the ant functional niche with respect to morphology, life history and behaviour at both individual and colony level. We calculated two complementary functional trait community indices ('trait average' and 'trait dissimilarity') for each trait, and we analysed how they varied along the three different gradients using generalized least squares models that accounted for spatial autocorrelation. Our results show that productivity, vegetation type and, to a lesser extent, each climate variable per se might play an important role in shaping the occurrence of functional species traits in ant communities. Among the climate variables, temperature and precipitation seasonality had a much higher influence on functional responses than their mean values, whose effects were almost lacking. Our results suggest that strong relationships might exist between the abiotic environment and the distribution of functional traits among south-western Mediterranean ant communities. This finding indicates that

  14. The functional response of a generalist predator.

    Directory of Open Access Journals (Sweden)

    Sophie Smout

    Full Text Available BACKGROUND: Predators can have profound impacts on the dynamics of their prey that depend on how predator consumption is affected by prey density (the predator's functional response. Consumption by a generalist predator is expected to depend on the densities of all its major prey species (its multispecies functional response, or MSFR, but most studies of generalists have focussed on their functional response to only one prey species. METHODOLOGY AND PRINCIPAL FINDINGS: Using Bayesian methods, we fit an MSFR to field data from an avian predator (the hen harrier Circus cyaneus feeding on three different prey species. We use a simple graphical approach to show that ignoring the effects of alternative prey can give a misleading impression of the predator's effect on the prey of interest. For example, in our system, a "predator pit" for one prey species only occurs when the availability of other prey species is low. CONCLUSIONS AND SIGNIFICANCE: The Bayesian approach is effective in fitting the MSFR model to field data. It allows flexibility in modelling over-dispersion, incorporates additional biological information into the parameter priors, and generates estimates of uncertainty in the model's predictions. These features of robustness and data efficiency make our approach ideal for the study of long-lived predators, for which data may be sparse and management/conservation priorities pressing.

  15. Electron velocity distribution function in a plasma with temperature gradient and in the presence of suprathermal electrons: application to incoherent-scatter plasma lines

    Directory of Open Access Journals (Sweden)

    P. Guio

    1998-10-01

    Full Text Available The plasma dispersion function and the reduced velocity distribution function are calculated numerically for any arbitrary velocity distribution function with cylindrical symmetry along the magnetic field. The electron velocity distribution is separated into two distributions representing the distribution of the ambient electrons and the suprathermal electrons. The velocity distribution function of the ambient electrons is modelled by a near-Maxwellian distribution function in presence of a temperature gradient and a potential electric field. The velocity distribution function of the suprathermal electrons is derived from a numerical model of the angular energy flux spectrum obtained by solving the transport equation of electrons. The numerical method used to calculate the plasma dispersion function and the reduced velocity distribution is described. The numerical code is used with simulated data to evaluate the Doppler frequency asymmetry between the up- and downshifted plasma lines of the incoherent-scatter plasma lines at different wave vectors. It is shown that the observed Doppler asymmetry is more dependent on deviation from the Maxwellian through the thermal part for high-frequency radars, while for low-frequency radars the Doppler asymmetry depends more on the presence of a suprathermal population. It is also seen that the full evaluation of the plasma dispersion function gives larger Doppler asymmetry than the heat flow approximation for Langmuir waves with phase velocity about three to six times the mean thermal velocity. For such waves the moment expansion of the dispersion function is not fully valid and the full calculation of the dispersion function is needed.Key words. Non-Maxwellian electron velocity distribution · Incoherent scatter plasma lines · EISCAT · Dielectric response function

  16. Electron velocity distribution function in a plasma with temperature gradient and in the presence of suprathermal electrons: application to incoherent-scatter plasma lines

    Directory of Open Access Journals (Sweden)

    P. Guio

    Full Text Available The plasma dispersion function and the reduced velocity distribution function are calculated numerically for any arbitrary velocity distribution function with cylindrical symmetry along the magnetic field. The electron velocity distribution is separated into two distributions representing the distribution of the ambient electrons and the suprathermal electrons. The velocity distribution function of the ambient electrons is modelled by a near-Maxwellian distribution function in presence of a temperature gradient and a potential electric field. The velocity distribution function of the suprathermal electrons is derived from a numerical model of the angular energy flux spectrum obtained by solving the transport equation of electrons. The numerical method used to calculate the plasma dispersion function and the reduced velocity distribution is described. The numerical code is used with simulated data to evaluate the Doppler frequency asymmetry between the up- and downshifted plasma lines of the incoherent-scatter plasma lines at different wave vectors. It is shown that the observed Doppler asymmetry is more dependent on deviation from the Maxwellian through the thermal part for high-frequency radars, while for low-frequency radars the Doppler asymmetry depends more on the presence of a suprathermal population. It is also seen that the full evaluation of the plasma dispersion function gives larger Doppler asymmetry than the heat flow approximation for Langmuir waves with phase velocity about three to six times the mean thermal velocity. For such waves the moment expansion of the dispersion function is not fully valid and the full calculation of the dispersion function is needed.

    Key words. Non-Maxwellian electron velocity distribution · Incoherent scatter plasma lines · EISCAT · Dielectric response function

  17. The coherent scattering function of the reptation model: simulations compared to theory.

    Science.gov (United States)

    Baumgärtner, A; Ebert, U; Schäfer, L

    2003-10-01

    We present results of Monte Carlo simulations measuring the coherent structure function of a chain moving through an ordered lattice of fixed topological obstacles. Our computer experiments use chains up to 320 beads and cover a large range of wave vectors and a time range exceeding the reptation time. For additional information we also measured the coherent structure function of internal pieces of the chain. We compare our results i) to the predictions of the primitive chain model, ii) to an approximate form resulting from Rouse motion in a coiled tube, and iii) to our recent evaluation of the full reptation model. i) The primitive chain model can fit the data for times t reptation time T(3) as a second fit parameter. For the chain lengths measured, the asymptotic behavior T3 approximately equal to N3 is not attained. ii) The model of Rouse motion in a tube, which we have criticized before on theoretical grounds, is shown to fail also on the purely phenomenological level. iii) Our evaluation of the full reptation model yields an excellent fit to the data for both total chains and internal pieces and for all wave vectors and all times, provided specific micro-structure effects of the MC dynamics are negligible. Such micro-structure effects show up for wave vectors of the order of the inverse segment size and enforce the introduction of some phenomenological, wave-vector-dependent prefactor. For the dynamics of the total chain our data analysis based on the full reptation model shows the importance of tube length fluctuations. Universal (Rouse-type) internal relaxation, however, is unimportant. It can be observed only in the form of the diffusive motion of a short central subchain in the tube. Finally, we present a fit formula which in a large range of wave vectors and chain lengths reproduces the numerical results of our theory for the scattering from the total chain.

  18. Functional and structural responses to marine urbanisation

    Science.gov (United States)

    Mayer-Pinto, M.; Cole, V. J.; Johnston, E. L.; Bugnot, A.; Hurst, H.; Airoldi, L.; Glasby, T. M.; Dafforn, K. A.

    2018-01-01

    Urban areas have broad ecological footprints with complex impacts on natural systems. In coastal areas, growing populations are advancing their urban footprint into the ocean through the construction of seawalls and other built infrastructure. While we have some understanding of how urbanisation might drive functional change in terrestrial ecosystems, coastal systems have been largely overlooked. This study is one of the first to directly assess how changes in diversity relate to changes in ecosystem properties and functions (e.g. productivity, filtration rates) of artificial and natural habitats in one of the largest urbanised estuaries in the world, Sydney Harbour. We complemented our surveys with an extensive literature search. We found large and important differences in the community structure and function between artificial and natural coastal habitats. However, differences in diversity and abundance of organisms do not necessarily match observed functional changes. The abundance and composition of important functional groups differed among habitats with rocky shores having 40% and 70% more grazers than seawalls or pilings, respectively. In contrast, scavengers were approximately 8 times more abundant on seawalls than on pilings or rocky shores and algae were more diverse on natural rocky shores and seawalls than on pilings. Our results confirm previous findings in the literature. Oysters were more abundant on pilings than on rocky shores, but were also smaller. Interestingly, these differences in oyster populations did not affect in situ filtration rates between habitats. Seawalls were the most invaded habitats while pilings supported greater secondary productivity than other habitats. This study highlights the complexity of the diversity-function relationship and responses to ocean sprawl in coastal systems. Importantly, we showed that functional properties should be considered independently from structural change if we are to design and manage artificial

  19. Instrumental resolution as a function of scattering angle and wavelength as exemplified for the POWGEN instrument.

    Science.gov (United States)

    Jacobs, Philipp; Houben, Andreas; Schweika, Werner; Tchougréeff, Andrei L; Dronskowski, Richard

    2017-06-01

    The method of angular- and wavelength-dispersive (e.g. two-dimensional) Rietveld refinement is a new and emerging tool for the analysis of neutron diffraction data measured at time-of-flight instruments with large area detectors. Following the approach for one-dimensional refinements (using either scattering angle or time of flight), the first step at each beam time cycle is the calibration of the instrument including the determination of instrumental contributions to the peak shape variation to be expected for diffraction patterns measured by the users. The aim of this work is to provide the users with calibration files and - for the later Rietveld refinement of the measured data - with an instrumental resolution file (IRF). This article will elaborate on the necessary steps to generate such an IRF for the angular- and wavelength-dispersive case, exemplified for the POWGEN instrument. A dataset measured on a standard diamond sample is used to extract the profile function in the two-dimensional case. It is found that the variation of reflection width with 2θ and λ can be expressed by the standard equation used for evaluating the instrumental resolution, which yields a substantially more fundamental approach to the parameterization of the instrumental contribution to the peak shape. Geometrical considerations of the POWGEN instrument and sample effects lead to values for Δθ, Δt and ΔL that yield a very good match to the extracted FWHM values. In a final step the refinement results are compared with the one-dimensional, i.e. diffraction-focused, case.

  20. Response predictions using the observed autocorrelation function

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam; H. Brodtkorb, Astrid; Jensen, Jørgen Juncher

    2018-01-01

    This article studies a procedure that facilitates short-time, deterministic predictions of the wave-induced motion of a marine vessel, where it is understood that the future motion of the vessel is calculated ahead of time. Such predictions are valuable to assist in the execution of many marine......-induced response in study. Thus, predicted (future) values ahead of time for a given time history recording are computed through a mathematical combination of the sample autocorrelation function and previous measurements recorded just prior to the moment of action. Importantly, the procedure does not need input...

  1. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  2. Quasielastic Scattering from Relativistic Bound Nucleons: R{sub TL} Response

    Energy Technology Data Exchange (ETDEWEB)

    J. A. Caballero; E. Moya de Guerra; J. M. Udias; J. E. Amaro; T. W. Donnelly

    1999-12-31

    Predictions of relativistic calculations for electron induced knock-out from the p{sub 1/2} and p{sub 3/2} shells in {sup 16}O are presented. Results for differential cross-section, TL response function and left-right asymmetry are compared to recent (e,e'p) data at Q{sup 2} = 0.8 (GeV/c){sup 2} taken at TJNAF. We show that the trend of the fully relativistic results is closely followed by the experimental data, pointing to the importance of both kinematical and dynamical relativistic effects in the nucleonic current.

  3. Measurement of the longitudinal deuteron spin-structure function in deep-inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, J.M.

    1996-09-01

    Experiment E143 at SLAC performed deep-inelastic scattering measurements with polarized electrons incident on polarized protons and deuterons. The data for the beam energy of 29 GeV cover the kinematical range of x{sub Bj} > 0.03 and 1 < Q{sup 2} < 12 GeV{sup 2}. From these data, the spin-dependent structure functions g{sub 1} were determined. This dissertation describes the experiment and its analysis and discusses the results. The measured integral of g{sub 1}{sup d} over x from x = 0 to x = 1 is {Gamma}{sub 1}{sup d} = 0.046 {+-} 0.003 (stat){+-}0.004 (syst) at Q{sup 2} = 3 GeV{sup 2} and disagrees by more than three standard deviations with the prediction of the Ellis-Jaffe, sum rule. The data suggest that the quark contribution to the nucleon helicity is 0.35 {+-} 0.05. From the proton data of the same experiment, the integral over the proton spin-structure functional g{sub 1}{sup d} was determined to be {Gamma}{sub 1}{sup p} = 0.127 {+-} 0.003(stat){+-}0.008(syst). By Combining the deuteron data with the proton data, the integral {Gamma}{sub 1}{sup n} was extracted as {minus}0.027 {+-} 0.008 (stat){+-}0.010 (syst). The integral {Gamma}{sub 1}{sup p} {minus} {Gamma}{sub 1}{sup n} is 0.154{+-}0.010(stat) {+-}0.016 (syst) according to the E143 analysis. This result agrees with the important Bjorken sum rule of 0.171 {+-} 0.009 at Q{sup 2} = 3 GeV{sup 2} within less than one standard deviation. Furthermore, results of a separate analysis involving GLAP evolution equations are shown. Data were also collected for beam energies of 16.2 and 9.7 GeV, Results for g{sub 1} at these energies are presented.

  4. Excitation Functions of the Analyzing Power in pp--> Scattering from 0.45 to 2.5 GeV

    Science.gov (United States)

    Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Busch, M.; Büßer, K.; Colberg, T.; Demirörs, L.; Diehl, O.; Engelhardt, H. P.; Eversheim, P. D.; Felden, O.; Gebel, R.; Glende, M.; Greiff, J.; Hinterberger, F.; Jonas, E.; Krause, H.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Meinerzhagen, A.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Schirm, N.; Schwarz, V.; Scobel, W.; Trelle, H. J.; Weise, E.; Wellinghausen, A.; Ziegler, R.

    2000-08-01

    Excitation functions AN\\(pp,Θc.m.\\) of the analyzing power in pp--> elastic scattering have been measured with a polarized atomic hydrogen target for projectile momenta pp between 1000 and 3300 MeV/ c. The experiment was performed for scattering angles 30°<=Θc.m.<=90° using the recirculating beam of the proton storage ring COSY during acceleration. The resulting excitation functions and angular distributions of high internal consistency have significant impact on the recent phase shift solution SAID SP99, in particular, on the spin triplet phase shifts between 1000 and 1800 MeV, and demonstrate the limited predictive power of single-energy phase shift solutions at these energies.

  5. Elastic proton-proton scattering: Excitation functions from 0.45 to 2.5 GeV

    Science.gov (United States)

    Hinterberger, F.; Bauer, F.; Bisplinghoff, J.; Büßer, K.; Busch, M.; Colberg, T.; Demirörs, L.; Dahl, C.; Eversheim, P. D.; Eyser, O.; Felden, O.; Gebel, R.; Greiff, J.; Jonas, E.; Krause, H.; Lehmann, C.; Lindlein, J.; Maier, R.; Meinerzhagen, A.; Pauli, C.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Schirm, N.; Scobel, W.; Ulbrich, K.; Weise, E.; Wolf, T.; Ziegler, R.

    Excitation functions of the differential cross sections {dσ}/{dgw}, analyzing powers AN and spin correlation parameters ANN, ASS and ASL have been measured with internal targets at the Cooler Synchrotron COSY. Data were taken continously during the acceleration and deceleration of the internal beam for kinetic energies between 450 and 2500 MeV and scattering angles 30° ⩽ σ cm ⩽ 90°. Details of the experimental method are presented. The results provide excitation functions and angular distributions of high precision and internal consistency. No evidence for narrow structures are found. Upper limits on the coupling of narrow resonances to elastic scattering in the mass range √ s = 2.2…2.8 GeV are deduced. The data have significant impact on phase shift solutions.

  6. Surface scattering from ceramic phosphors

    Science.gov (United States)

    Lenef, Alan; Kelso, John; Peters, Christopher

    2012-02-01

    Scattering from phosphor converters and epitaxial surfaces is critical for solid state lighting device performance. Volume and surface scattering in solid state lighting devices can play a critical role in efficiency/efficacy, color points, and color angular consistency. Surface scattering in particular has not been well characterized in solid state lighting devices and can be complex to model. Because large angle scattering is important in lighting applications, surface scattering models generally require vector electromagnetic theory to avoid ambiguities often associated with scalar theory at these angles. Furthermore, surface features are often on the order of a few wavelengths, bringing ray tracing approaches into question. In this work, experimental angular scattering measurements are made on ceramic phosphor components where surface scattering dominates. The surface ceramic grain structure is responsible for the scattering. The results are compared to approximate statistical vector theory predictions that use the height autocorrelation functions as input. The autocorrelation measurements were derived from atomic-force microscopy topography measurements. Resulting predictions are in fairly good agreement with measurements.

  7. Relationship between the atomic pair distribution function and small-angle scattering: implications for modeling of nanoparticles.

    Science.gov (United States)

    Farrow, Christopher L; Billinge, Simon J L

    2009-05-01

    The relationship between the equations used in the atomic pair distribution function (PDF) method and those commonly used in small-angle-scattering (SAS) analyses is explicitly shown. The origin of the sloping baseline, -4pirrho0, in PDFs of bulk materials is identified as originating from the SAS intensity that is neglected in PDF measurements. The nonlinear baseline in nanoparticles has the same origin, and contains information about the shape and size of the nanoparticles.

  8. Hadron production in high energy muon scattering. [Quark-parton model, 225 GeV, structure functions, particle ratios

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, R.G.

    1978-01-01

    An experiment was performed to study muon-proton scattering at an incident energy of 225 GeV and a total effective flux of 4.3 x 10/sup 10/ muons. This experiment is able to detect charged particles in coincidence with the scattered muon in the forward hemisphere, and results are reported for the neutral strange particles K/sub s//sup 0/ and ..lambda../sup 0/ decaying into two charged particles. Within experimental limits the masses and lifetimes of these particles are consistent with previous measurements. The distribution of hadrons produced in muon scattering is determined, measuring momentum components parallel and transverse to the virtual photon direction, and these distributions are compared to other high energy experiments involving the scattering of pions, protons, and neutrinos from protons. Structure functions for hadron production and particle ratios are calculated. No azimuthal dependence is observed, and lambda production does not appear to be polarized. The physical significance of the results is discussed within the framework of the quark-parton model. 29 references.

  9. Deconvolution of Camera Instrument Response Functions.

    Science.gov (United States)

    Lewis, John H; Jamiolkowski, Ryan M; Woody, Michael S; Ostap, E Michael; Goldman, Yale E

    2017-03-28

    Temporal sequences of fluorescence intensities in single-molecule experiments are often obtained from stacks of camera images. The dwell times of different macromolecular structural or functional states, correlated with characteristic fluorescence intensities, are extracted from the images and combined into dwell time distributions that are fitted by kinetic functions to extract corresponding rate constants. The frame rate of the camera limits the time resolution of the experiment and thus the fastest rate processes that can be reliably detected and quantified. However, including the influence of discrete sampling (framing) on the detected time series in the fitted model enables rate processes near to the frame rate to be reliably estimated. This influence, similar to the instrument response function in other types of instruments, such as pulsed emission decay fluorometers, is easily incorporated into the fitted model. The same concept applies to any temporal data that is low-pass filtered or decimated to improve signal to noise ratio. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  10. Structure and optical function of amorphous photonic nanostructures from avian feather barbs: a comparative small angle X-ray scattering (SAXS) analysis of 230 bird species.

    Science.gov (United States)

    Saranathan, Vinodkumar; Forster, Jason D; Noh, Heeso; Liew, Seng-Fatt; Mochrie, Simon G J; Cao, Hui; Dufresne, Eric R; Prum, Richard O

    2012-10-07

    Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy β-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and optical spectrophotometry, we characterized the nanostructure and optical function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the single-scattering peak of the optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing β-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic optical properties may provide biomimetic inspiration for photonic technology.

  11. Monitoring the Response of Roads and Railways to Seasonal Soil Movement with Persistent Scatterers Interferometry over Six UK Sites

    Directory of Open Access Journals (Sweden)

    Matthew North

    2017-09-01

    Full Text Available Road and rail networks provide critical support for society, yet they can be degraded by seasonal soil movements. Currently, few transport network operators monitor small-scale soil movement, but understanding the conditions contributing to infrastructure failure can improve network resilience. Persistent Scatterers Interferometry (PSI is a remote sensing technique offering the potential for near real-time ground movement monitoring over wide areas. This study tests the use of PSI for monitoring the response of major roads, minor roads, and railways to ground movement across six study sites in England, using Sentinel 1 data in VV polarisation in ascending orbit. Some soils are more stable than others—a national soil map was used to quantify the relationships between infrastructure movement and major soil groups. Vertical movement of transport infrastructure is a function of engineering design, soil properties, and traffic loading. Roads and railways built on soil groups prone to seasonal water-logging (Ground-water Gley soils, Surface-water Gley soils, Pelosols, and Brown soils demonstrated seasonal subsidence and heave, associated with an increased risk of infrastructure degradation. Roads and railways over Podzolic soils demonstrated relative stability. Railways on Peat soils exhibited the most extreme continual subsidence of up to 7.5 mm year−1. Limitations of this study include the short observation period (~13 months, due to satellite data availability and the regional scale of the soil map—mapping units contain multiple soil types with different ground movement potentials. Future use of a higher resolution soil map over a longer period will advance this research. Nevertheless, this study demonstrates the viability of PSI as a technique for measuring both seasonal soil-related ground movement and the associated impacts on road and rail infrastructure.

  12. Using light scattering to measure the response of individual ultrasound contrast microbubbles subjected to pulsed ultrasound in vitro

    Science.gov (United States)

    Guan, Jingfeng; Matula, Thomas J.

    2004-11-01

    Light scattering was used to measure the radial pulsations of individual ultrasound contrast microbubbles subjected to pulsed ultrasound. Highly diluted Optison® or Sonazoid® microbubbles were injected into either a water bath or an aqueous solution containing small quantities of xanthan gum. Individual microbubbles were insonified by ultrasound pulses from either a commercial diagnostic ultrasound machine or a single element transducer. The instantaneous response curves of the microbubbles were measured. Linear and nonlinear microbubble oscillations were observed. Good agreement was obtained by fitting a bubble dynamics model to the data. The pulse-to-pulse evolution of individual microbubbles was investigated, the results of which suggest that the shell can be semipermeable, and possibly weaken with subsequent pulses. There is a high potential that light scattering can be used to optimize diagnostic ultrasound techniques, understand microbubble evolution, and obtain specific information about shell parameters. .

  13. Functional, Responsive Materials Assembled from Recombinant Oleosin

    Science.gov (United States)

    Hammer, Daniel

    Biological cells are surrounded by a plasma membrane made primarily of phospholipids that form a bilayer. This membrane is permselective and compartmentalizes the cell. A simple form of artificial cell is the vesicle, in which a phospholipid bilayer membrane surrounds an aqueous solution. However, there is no a priori reason why a membrane needs to be made of phospholipids. It could be made of any surfactant that forms a bilayer. We have assembled membranes and other structures from the recombinant plant protein oleosin. The ability to assemble from a recombinant protein means that every molecule is identical, we have complete control over the sequence, and hence can build in designer functionality with high fidelity, including adhesion and enzymatic activity. Such incorporation is trivial using the tools of molecular biology. We find that while many variants of oleosin make membranes, others make micelles and sheets. We show how the type of supramolecular structure can be altered by the conditions of solvent, such as ionic strength, and the architecture of the surfactant itself. We show that protease cleavable domains can be incorporated within oleosin, and be engineered to protect other functional domains such as adhesive motifs, to make responsive materials whose activity and shape depend on the action of proteases. We will also present the idea of making ``Franken''-oleosins, where large domains of native oleosin are replaced with domains from other functional proteins, to make hybrids conferred by the donor protein. Thus, we can view oleosin as a template upon which a vast array of designer functionalities can be imparted..

  14. Resting state functional connectivity predicts neurofeedback response

    Directory of Open Access Journals (Sweden)

    Dustin eScheinost

    2014-09-01

    Full Text Available Tailoring treatments to the specific needs and biology of individual patients – personalized medicine – requires delineation of reliable predictors of response. Unfortunately, these have been slow to emerge, especially in neuropsychiatric disorders. We have recently described a real-time functional magnetic resonance imaging (rt-fMRI neurofeedback protocol that can reduce contamination-related anxiety, a prominent symptom of many cases of obsessive-compulsive disorder (OCD. Individual response to this intervention is variable. Here we used patterns of brain functional connectivity, as measured by baseline resting-state fMRI (rs-fMRI, to predict improvements in contamination anxiety after neurofeedback training. Activity of a region of the orbitofrontal cortex (OFC and anterior prefrontal cortex, Brodmann area (BA 10, associated with contamination anxiety in each subject was measured in real time and presented as a neurofeedback signal, permitting subjects to learn to modulate this target brain region. We have previously reported both enhanced OFC/BA 10 control and improved anxiety in a group of subclinically anxious subjects after neurofeedback. Five individuals with contamination-related OCD who underwent the same protocol also showed improved clinical symptomatology. In both groups, these behavioral improvements were strongly correlated with baseline whole-brain connectivity in the OFC/BA 10, computed from rs-fMRI collected several days prior to neurofeedback training. These pilot data suggest that rs-fMRI can be used to identify individuals likely to benefit from rt-fMRI neurofeedback training to control contamination anxiety.

  15. Electromagnetic Scattering from Vegetation Canopies.

    Science.gov (United States)

    Sarabandi, Kamal

    Satellite-borne imaging radar has been proposed by the remote sensing community as a potential sensor for the acquisition of quantitative information about forested area on a global scale. To achieve this goal, it is necessary to develop retrieved algorithms that can provide reasonable estimate of vegetation biomass, leaf moisture content, and other physical parameters of tree canopies from multifrequency/multipolarization observations of their radar backscattering coefficients. Retrieval algorithms often are called "inverse problem" because their input/output parameters are the inverse of those associated with the direct problem, which in the present case refers to the development of a radar scattering model that relates the radar response to the canopy architecture and associated parameters. This thesis provides electromagnetic solutions to several problems associated with scattering from tree canopies. The forest canopy is modelled in the form of layers comprised of randomly distributed particles with known statistical properties. In Chapters 2-8 effective scattering models for different constituent particles of vegetation canopies are developed by employing appropriate asymptotic solutions and approximations. The effects of various physical features of the particles, such as curvature and variation in thickness for planar leaves and roughness for tree trunks, on their scattering behavior are examined. In Chapter 9 the scattering problem of inhomogeneous layered media is formulated via the vector radiative transfer equations and a first-order solution for the radar scattering coefficients is obtained. The radiative transfer solution is formulated in terms of two sets of input functions: the scattering matrices of the constituent particles, which are given in Chapters 2-8, and the size and orientation distribution functions of the particles. The radar scattering model and associated input functions can be used to conduct sensitivity analyses to determine the

  16. 28 CFR 800.3 - Functions and responsibilities.

    Science.gov (United States)

    2010-07-01

    ... COLUMBIA ORGANIZATION AND FUNCTIONS § 800.3 Functions and responsibilities. (a) Community Supervision... social intervention programs that decrease the likelihood of future criminal behavior. ...

  17. Omentin functions to attenuate cardiac hypertrophic response.

    Science.gov (United States)

    Matsuo, Kazuhiro; Shibata, Rei; Ohashi, Koji; Kambara, Takahiro; Uemura, Yusuke; Hiramatsu-Ito, Mizuho; Enomoto, Takashi; Yuasa, Daisuke; Joki, Yusuke; Ito, Masanori; Hayakawa, Satoko; Ogawa, Hayato; Kihara, Shinji; Murohara, Toyoaki; Ouchi, Noriyuki

    2015-02-01

    Cardiac hypertrophy occurs in many obesity-related conditions. Omentin is an adipose-derived plasma protein that is downregulated under obese conditions. Here, we investigated whether omentin modulates cardiac hypertrophic responses in vivo and in vitro. Systemic administration of an adenoviral vector expressing human omentin (Ad-OMT) to wild-type (WT) mice led to the attenuation of cardiac hypertrophy, fibrosis and ERK phosphorylation induced by transverse aortic constriction (TAC) or angiotensin II infusion. In cultured cardiomyocytes, stimulation with phenylephrine (PE) led to an increase in myocyte size, which was prevented by pretreatment with human omentin protein. Pretreatment of cardiomyocytes with omentin protein also reduced ERK phosphorylation in response to PE stimulation. Ad-OMT enhanced phosphorylation of AMP-activated protein kinase (AMPK) in the heart of WT mice after TAC operation. Blockade of AMPK activation by transduction with dominant-negative mutant forms of AMPK reversed the inhibitory effect of omentin on myocyte hypertrophy and ERK phosphorylation following PE stimulation. Moreover, fat-specific transgenic mice expressing human omentin showed reduced cardiac hypertrophy and ERK phosphorylation following TAC surgery compared to littermate controls. These data suggest that omentin functions to attenuate the pathological process of myocardial hypertrophy via the activation of AMPK in the heart, suggesting that omentin may represent a target molecule for the treatment of cardiac hypertrophy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. An equipment for measuring 3D bi-directional scattering distribution function of black painted and differently machined surfaces

    Science.gov (United States)

    Barilli, M.; Mazzoni, A.

    2005-09-01

    Bi-directional Reflectance Distribution Function (BRDF) measurements that characterise the scattering properties of surfaces are extremely important to the design of optical instruments. Sophisticated codes require the characterisation of the scattering function of optically black and/or differently machined surfaces at several angle of incidence in a wide range of detector angles. These data can be used to develop processes to achieve desired BRDF patterns or to improve stray light suppression techniques. In this paper, we present the characteristics of an automatic, three dimensional, BRDF measurement set up that has been designed and developed at Galileo Avionica by the authors and the most significant experimental results of 3D BRDF data achieved on samples of aluminium alloys, gold and titanium, differently machined and/or black painted. The measurements have been taken at different illumination angles (from the normal incidence up to 45 degrees) at the wavelength of 650 nm. The wide variety of possible applications that can be explored through the proposed equipment, jointed to its flexibility, constitute a reference point for future investigations on the characterisation of the scattering properties of machined materials and paintings.

  19. Confluent Heun functions and the physics of black holes: Resonant frequencies, Hawking radiation and scattering of scalar waves

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, H.S., E-mail: horacio.santana.vieira@hotmail.com [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil); Centro de Ciências, Tecnologia e Saúde, Universidade Estadual da Paraíba, CEP 58233-000, Araruna, PB (Brazil); Bezerra, V.B., E-mail: valdir@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, CEP 58051-970, João Pessoa, PB (Brazil)

    2016-10-15

    We apply the confluent Heun functions to study the resonant frequencies (quasispectrum), the Hawking radiation and the scattering process of scalar waves, in a class of spacetimes, namely, the ones generated by a Kerr–Newman–Kasuya spacetime (dyon black hole) and a Reissner–Nordström black hole surrounded by a magnetic field (Ernst spacetime). In both spacetimes, the solutions for the angular and radial parts of the corresponding Klein–Gordon equations are obtained exactly, for massive and massless fields, respectively. The special cases of Kerr and Schwarzschild black holes are analyzed and the solutions obtained, as well as in the case of a Schwarzschild black hole surrounded by a magnetic field. In all these special situations, the resonant frequencies, Hawking radiation and scattering are studied. - Highlights: • Charged massive scalar field in the dyon black hole and massless scalar field in the Ernst spacetime are analyzed. • The confluent Heun functions are applied to obtain the solution of the Klein–Gordon equation. • The resonant frequencies are obtained. • The Hawking radiation and the scattering process of scalar waves are examined.

  20. Compton scattering

    Energy Technology Data Exchange (ETDEWEB)

    Botto, D.J.; Pratt, R.H.

    1979-05-01

    The current status of Compton scattering, both experimental observations and the theoretical predictions, is examined. Classes of experiments are distinguished and the results obtained are summarized. The validity of the incoherent scattering function approximation and the impulse approximation is discussed. These simple theoretical approaches are compared with predictions of the nonrelativistic dipole formula of Gavrila and with the relativistic results of Whittingham. It is noted that the A/sup -2/ based approximations fail to predict resonances and an infrared divergence, both of which have been observed. It appears that at present the various available theoretical approaches differ significantly in their predictions and that further and more systematic work is required.

  1. Scattering phase function spectrum makes reflectance spectrum measured from Intralipid phantoms and tissue sensitive to the device detection geometry

    Science.gov (United States)

    Kanick, S. C.; Krishnaswamy, V.; Gamm, U. A.; Sterenborg, H. J. C. M.; Robinson, D. J.; Amelink, A.; Pogue, B. W.

    2012-01-01

    Reflectance spectra measured in Intralipid (IL) close to the source are sensitive to wavelength-dependent changes in reduced scattering coefficient (μ′s) and scattering phase function (PF). Experiments and simulations were performed using device designs with either single or separate optical fibers for delivery and collection of light in varying concentrations of IL. Spectral reflectance is not consistently linear with varying IL concentration, with PF-dependent effects observed for single fiber devices with diameters smaller than ten transport lengths and for separate source-detector devices that collected light at less than half of a transport length from the source. Similar effects are thought to be seen in tissue, limiting the ability to quantitatively compare spectra from different devices without compensation. PMID:22567598

  2. Response for light scattered in the ocular fundus from double-pass and Hartmann-Shack estimations.

    Science.gov (United States)

    García-Guerra, Carlos E; Aldaba, Mikel; Arjona, Montserrat; Díaz-Doutón, Fernando; Martínez-Roda, Joan A; Pujol, Jaume

    2016-11-01

    Double-pass (DP) and Hartmann-Shack (HS) are complementary techniques based on reflections of light in the ocular fundus that may be used to estimate the optical properties of the human eye. Under conventional data processing, both of these assessment modes provide information on aberrations. In addition, DP data contain the effects of scattering. In the ocular fundus, this phenomenon may arise from the interaction of light with not only the retina, but also deeper layers up to which certain wavelengths may penetrate. In this work, we estimate the response of the ocular fundus to incident light by fitting the deviations between DP and HS estimations using an exponential model. In measurements with negligible intraocular scattering, such differences may be related to the lateral spreading of light that occurs in the ocular fundus due to the diffusive properties of the media at the working wavelength. The proposed model was applied in young healthy eyes to evaluate the performance of scattering in such a population. Besides giving a parameter with information on the ocular fundus, the model contributes to the understanding of the differences between DP and HS estimations.

  3. The Effects of Scattered Light from Optical Components on Visual Function

    Science.gov (United States)

    2016-02-01

    four haze standards, four LEP of the reflective type, and one NDF. The haze standards were glass plates with particles suspended in them to yield...test and Standard Pseudoisochromatic Plates , Part 2), and no self-reported vision problems. Observers were also not taking any medications that might...collected in this study need to be accompanied by subjective data on observer ratings of scatter/haze and acceptability of the LEP for use in the cockpit

  4. Waste Fiber Powder Functionalized with Silver Nanoprism for Enhanced Raman Scattering Analysis

    OpenAIRE

    Tang, Bin; Zeng, Tian; Liu, Jun; Zhou, Ji; Ye, Yong; Wang, Xungai

    2017-01-01

    Biomass disks based on fine powder produced from disposed wool fibers were prepared for surface-enhanced Raman scattering (SERS). The wool powders (WPs) were modified by silver nanoprisms via an assembly method and then pressed into disks using a hydraulic laboratory pellet press. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the WPs and disks before and after treatment with silver nanoparticles (AgNPs). The W...

  5. An electrical analogy to Mie scattering.

    Science.gov (United States)

    Caridad, José M; Connaughton, Stephen; Ott, Christian; Weber, Heiko B; Krstić, Vojislav

    2016-09-27

    Mie scattering is an optical phenomenon that appears when electromagnetic waves, in particular light, are elastically scattered at a spherical or cylindrical object. A transfer of this phenomenon onto electron states in ballistic graphene has been proposed theoretically, assuming a well-defined incident wave scattered by a perfectly cylindrical nanometer scaled potential, but experimental fingerprints are lacking. We present an experimental demonstration of an electrical analogue to Mie scattering by using graphene as a conductor, and circular potentials arranged in a square two-dimensional array. The tabletop experiment is carried out under seemingly unfavourable conditions of diffusive transport at room-temperature. Nonetheless, when a canted arrangement of the array with respect to the incident current is chosen, cascaded Mie scattering results robustly in a transverse voltage. Its response on electrostatic gating and variation of potentials convincingly underscores Mie scattering as underlying mechanism. The findings presented here encourage the design of functional electronic metamaterials.

  6. Sinc-interpolants in the energy plane for regular solution, Jost function, and its zeros of quantum scattering

    Science.gov (United States)

    Annaby, M. H.; Asharabi, R. M.

    2018-01-01

    In a remarkable note of Chadan [Il Nuovo Cimento 39, 697-703 (1965)], the author expanded both the regular wave function and the Jost function of the quantum scattering problem using an interpolation theorem of Valiron [Bull. Sci. Math. 49, 181-192 (1925)]. These expansions have a very slow rate of convergence, and applying them to compute the zeros of the Jost function, which lead to the important bound states, gives poor convergence rates. It is our objective in this paper to introduce several efficient interpolation techniques to compute the regular wave solution as well as the Jost function and its zeros approximately. This work continues and improves the results of Chadan and other related studies remarkably. Several worked examples are given with illustrations and comparisons with existing methods.

  7. Detection and characterization of nanoparticles in suspension at low concentrations using the X-ray total scattering pair distribution function technique

    Energy Technology Data Exchange (ETDEWEB)

    Terban, Maxwell W. [Department of Applied Physics and Applied Mathematics; Columbia University; New York, USA; Johnson, Matthew [GlaxoSmithKline Medicines Research Centre; Hertfordshire, UK; Di Michiel, Marco [ESRF – The European Synchrotron; 38043 Grenoble Cedex 9, France; Billinge, Simon J. L. [Department of Applied Physics and Applied Mathematics; Columbia University; New York, USA; Condensed Matter Physics and Materials Science Department; Brookhaven National Laboratory

    2015-01-01

    Total scattering experiments are used with pair distribution function analysis to study nanoscale structure and morphology in highly disordered samples. We investigate sensitivity for the case of organic nanoparticles in dilute solution.

  8. Lectures in scattering theory

    CERN Document Server

    Sitenko, A G

    1971-01-01

    Lectures in Scattering Theory discusses problems in quantum mechanics and the principles of the non-relativistic theory of potential scattering. This book describes in detail the properties of the scattering matrix and its connection with physically observable quantities. This text presents a stationary formulation of the scattering problem and the wave functions of a particle found in an external field. This book also examines the analytic properties of the scattering matrix, dispersion relations, complex angular moments, as well as the separable representation of the scattering amplitude. Th

  9. Lymphatic function and responses in periodontal disease.

    Science.gov (United States)

    Berggreen, Ellen; Wiig, Helge

    2014-07-15

    Extravasated fluid, proteins and cells are returned into the circulation by lymphatic vessels that are also important in immune cell trafficking. Lymphatic vessels in gingiva are located in lamina propria, and traverse the external surface of the alveolar bone. Lack of gingival lymphatics has been shown to increase the interstitial fluid pressure and fluid volume, thus showing that lymphatics are important for fluid drainage also in this tissue. Gingival lymphatic vessels require continuous signaling by the growth factors VEGF-C and D via their receptor VEGFR-3 for their maintenance, factors that are expressed in the gingival epithelium and also in immune cells in lamina propria. VEGF-C seems to be of critical importance for lymphangiogeneses induced during periodontal disease development. Mice are protected against periodontitis by lymphatics clearing bacteria and bacterial products and promoting humoral immune responses. CCL21, a ligand important for dendritic cell migration, has been found to be downregulated in lymphatics from patients with periodontitis. Such patients may have impaired gingival lymphatic function due to high enzymatic activity and thus loss of structural components in the interstitium. At present there are few studies on the role of lymphatic vessels in periodontal disease making this a rather unexplored field. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Calculation of the cluster size distribution functions and small-angle neutron scattering data for C60/N-methylpyrrolidone

    Science.gov (United States)

    Tropin, T. V.; Jargalan, N.; Avdeev, M. V.; Kyzyma, O. A.; Sangaa, D.; Aksenov, V. L.

    2014-01-01

    The aggregate growth in a C60/N-methylpyrrolidone (NMP) solution has been considered in the framework of the approach developed earlier for describing the cluster growth kinetics in fullerene polar solutions. The final cluster size distribution functions in model solutions have been estimated for two fullerene aggregation models including the influence of complex formation on the cluster growth using extrapolations of the characteristics of the cluster state and distribution parameters. Based on the obtained results, the model curves of small-angle neutron scattering have been calculated for a C60/NMP solution at various values of the model parameters.

  11. Periodic solution for the stochastic chemostat with general response function

    Science.gov (United States)

    Wang, Liang; Jiang, Daqing

    2017-11-01

    This paper addresses a stochastic chemostat model with periodic dilution rate and general class of response functions. The general functional response is assumed to satisfy two classifications of conditions, and these assumptions on the functional response are relative weak that are valid for many forms of growth response. For the chemostat with periodic dilution rate, we derive the sufficient criteria for the existence of the stochastic nontrivial positive periodic solution, by utilizing Khasminskii's theory on periodic Markov process.

  12. Nonperturbative Series Expansion of Green's Functions: The Anatomy of Resonant Inelastic X-Ray Scattering in the Doped Hubbard Model

    Science.gov (United States)

    Lu, Yi; Haverkort, Maurits W.

    2017-12-01

    We present a nonperturbative, divergence-free series expansion of Green's functions using effective operators. The method is especially suited for computing correlators of complex operators as a series of correlation functions of simpler forms. We apply the method to study low-energy excitations in resonant inelastic x-ray scattering (RIXS) in doped one- and two-dimensional single-band Hubbard models. The RIXS operator is expanded into polynomials of spin, density, and current operators weighted by fundamental x-ray spectral functions. These operators couple to different polarization channels resulting in simple selection rules. The incident photon energy dependent coefficients help to pinpoint main RIXS contributions from different degrees of freedom. We show in particular that, with parameters pertaining to cuprate superconductors, local spin excitation dominates the RIXS spectral weight over a wide doping range in the cross-polarization channel.

  13. Microwave responses and general model of nanotetraneedle ZnO: Integration of interface scattering, microcurrent, dielectric relaxation, and microantenna

    Science.gov (United States)

    Fang, Xiao-Yong; Cao, Mao-Sheng; Shi, Xiao-Ling; Hou, Zhi-Ling; Song, Wei-Li; Yuan, Jie

    2010-03-01

    Based on the unique geometrical structure of nanotetra-ZnO needle (T-ZnON), we investigate the microwave responses of T-ZnON, including interface scattering, microcurrent attenuation, microantenna radiation, and dielectric relaxation, and build an energy attenuation model. The associated quantitative formula is deduced for calculating the microwave absorption properties of T-ZnON/SiO2 nanocomposite (T-ZnON/SiO2) in the range 8-14 GHz according to the present energy attenuation model. Very good agreement between the calculated and experimental results is obtained in a wide frequency range. The maximum deviation less than 0.5 dB in the range 8-14 GHz is obtained. Using the aforementioned model, we analyze the contribution of microwave responses to the energy attenuation in the frequency range 2-18 GHz, and the results reveal that interface scattering and microcurrent attenuation make the contribution most important. In addition, we calculate the effects of the volume fraction, conductivity, permittivity, needle length of T-ZnON, and thickness of T-ZnON/SiO2 on the reflectivity. The results show that the microwave absorption is evidently dependent on these effect factors, and the optimal microwave absorption band and the strongest microwave absorption peak of T-ZnON/SiO2 would appear when these physical parameters are changed.

  14. A New Smart Surface-Enhanced Raman Scattering Sensor Based on pH-Responsive Polyacryloyl Hydrazine Capped Ag Nanoparticles

    Science.gov (United States)

    Yuan, Shuai; Ge, Fengyan; Zhou, Man; Cai, Zaisheng; Guang, Shanyi

    2017-08-01

    A novel pH-responsive Ag@polyacryloyl hydrazide (Ag@PAH) nanoparticle for the first time as a surface-enhanced Raman scattering (SERS) substrate was prepared without reducing agent and end-capping reagent. Ag@PAH nanoparticles exhibited an excellent tunable detecting performance in the range from pH = 4 to pH = 9. This is explained that the swelling-shrinking behavior of responsive PAH can control the distance between Ag NPs and the target molecules under external pH stimuli, resulting in the tunable LSPR and further controlled SERS. Furthermore, Ag@PAH nanoparticles possessed an ultra-sensitive detecting ability and the detection limit of Rhodamine 6G reduced to 10-12 M. These advantages qualified Ag@PAH NP as a promising smart SERS substrate in the field of trace analysis and sensors.

  15. Distorted spin dependent spectral function of {sup 3}He and semi-inclusive deep inelastic scattering processes

    Energy Technology Data Exchange (ETDEWEB)

    Kaptari, Leonya P. [University of Perugia (Italy); INFN-Perugia (Italy); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Joint Inst. for Nuclear Research, Dubna (Russia); Del Dotto, Alessio [University of Rome, Rome (Italy); INFN-Roma (Italy); Pace, Emanuele [University of Rome (Italy); INFN-Tor Vergata (Italy); Salme, Giovanni [INFN-Roma (Italy); Scopetta, Sergio [University of Perugia (Italy); INFN-Perugia (Italy)

    2014-03-01

    The spin dependent spectral function, relevant to describe polarized electron scattering off polarized {sup 3}He, is studied, within the Plane Wave Impulse Approximation and taking into account final state interaction effects (FSI). In particular, the case of semi-inclusive deep inelastic scattering (SiDIS) is considered, evaluating the FSI of the hadronizing quark with the nuclear remnants. It is shown that particular kinematical regions can be selected to minimize the latter effects, so that parton distributions in the neutron can be accessed. On the other side, in the regions where FSI dominates, the considered reactions can elucidate the mechanism of hadronization of quarks during the propagation in the nuclear medium. It is shown that the obtained spin dependent spectral function can be directly applied to investigate the SiDIS reaction e-vector + {sup 3}He-vector to h+X, where the hadron h originates from the current fragmentation. Experiments of this type are being performed at JLab to extract neutron transverse momentum dependent parton distributions. As a case study, a different SiDIS process, with detection of slow (A-1) systems in the final state, is considered in more details, in order to establish when nuclear structure effects and FSI can be distinguished from elementary reactions on quasi-free nucleons. It is argued that, by a proper choice of kinematics, the origin of nuclear effects in polarized DIS phenomena and the details of the interaction between the hadronizing quark and the nuclear medium can be investigated at a level which is not reachable in inclusive deep inelastic scattering.

  16. Applications of Total Scattering & Pair Distribution Function Analysis in Metal-Organic Framework Materials

    DEFF Research Database (Denmark)

    Xu, Hui; Birgisson, Steinar; Sommer, Sanna

    Metal-Organic Frameworks (MOFs) is constructed by metal-oxide nodes and organic ligands. The formation of different structures of metal-oxide nodes (also called secondary building units, SBU) is crucial for MOF final structures, because the connectivity of SBU greatly influence the final MOF...... structure. At the same time, there is an ongoing debate on whether the SBU is present prior, or during MOF crystallization in MOF chemistry. However, little is known about MOFs formation mechanism. Currently techniques to study the in situ MOF formation process mainly focused on after......-crystallization process, for example in situ XRD and SAXS/WAXS study on MOF formation. However, the pre-crystallization process in the early stage of MOF formation is still unexplored. In this project, total scattering and PDF study will be carried out to explore the MOF formation process in early stage. This includes...

  17. Coping responses as predictors of psychosocial functioning ...

    African Journals Online (AJOL)

    Background: Research on coping with chronic pain has focused on exploring the impact of different coping responses on various aspects of living with chronic pain. The aim of this study is to determine whether certain coping responses can be identified as predictors of the level of pain intensity reported by the chronic pain ...

  18. Measuring the Scatter of the Mass–Richness Relation in Galaxy Clusters in Photometric Imaging Surveys by Means of Their Correlation Function

    Energy Technology Data Exchange (ETDEWEB)

    Campa, Julia; Estrada, Juan; Flaugher, Brenna

    2017-02-03

    The knowledge of the scatter in the mass-observable relation is a key ingredient for a cosmological analysis based on galaxy clusters in a photometric survey. We demonstrate here how the linear bias measured in the correlation function for clusters can be used to determine the value of the scatter. The new method is tested in simulations of a 5.000 square degrees optical survey up to z~1, similar to the ongoing Dark Energy Survey. The results indicate that the scatter can be measured with a precision of 5% using this technique.

  19. Autoimmune Response Confers Decreased Cardiac Function in ...

    African Journals Online (AJOL)

    Conclusion: Valve replacement in patients with rheumatic heart disease (RHD) does not attenuate ... valve replacement. Clinically, two-dimensional echocardiography is widely used as an effective approach to evaluate cardiac function heart function of patients with ... neurologic disorders, renal or liver disease, acute.

  20. Retrieval of Green's function and generalized optical theorem for the scattering of complete dyadic fields.

    Science.gov (United States)

    Lu, Laiyu; Ding, Zhifeng; Zeng, Rong Sheng; He, Zhengqin

    2011-04-01

    Green's function retrieval has been widely used in different research fields due to the fact that the Green's function can be extracted by cross-correlating the records at two receivers. In this paper, the retrieval of the dyadic Green's function is studied by investigating the representation theorem. The generalized optical theorem for the dyadic fields is derived based on the elastic dynamic interferometric equation. By addressing the cross-correlation recorded at two receivers, the important role of the generalized optical theorem and energy equipartition in retrieving the exact Green's function is shown. The presented derivation also shows the Newton-Marchenko equation holdsif the condition of equipartition is not satisfied.

  1. Waste Fiber Powder Functionalized with Silver Nanoprism for Enhanced Raman Scattering Analysis

    Science.gov (United States)

    Tang, Bin; Zeng, Tian; Liu, Jun; Zhou, Ji; Ye, Yong; Wang, Xungai

    2017-05-01

    Biomass disks based on fine powder produced from disposed wool fibers were prepared for surface-enhanced Raman scattering (SERS). The wool powders (WPs) were modified by silver nanoprisms via an assembly method and then pressed into disks using a hydraulic laboratory pellet press. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the WPs and disks before and after treatment with silver nanoparticles (AgNPs). The WPs retained porous structures after treatment with AgNPs. The silver nanoprisms on WPs were observed clearly and the localized surface plasmon resonance (LSPR) properties of silver nanoprisms led to blue color of wool powder (WP). The obtained WP disks with AgNPs were confirmed to enhance greatly the Raman signal of thiram. The SERS disks are low-cost and convenient to use, with high sensitivity. The characteristic SERS bands of 10-8 M thiram can be identified from WP disks containing silver nanoparticles.

  2. Estimation of Frequency Response Functions by Random Decrement

    DEFF Research Database (Denmark)

    Asmussen, J. C.; Brincker, Rune

    1996-01-01

    A method for estimating frequency response functions by the Random Decrement technique is investigated in this paper. The method is based on the auto and cross Random Decrement functions of the input process and the output process of a linear system. The Fourier transformation of these functions ...... Decrement function. The method is demonstrated by a simulation study....

  3. Mapping three-dimensional near-field responses with reconstruction scattering-type scanning near-field optical microscopy

    Science.gov (United States)

    Wang, Haomin; Wang, Le; Jakob, Devon S.; Xu, Xiaoji G.

    2017-05-01

    Scattering-type scanning near-field optical microscopy (s-SNOM) enables mapping of nanoscale field distributions in two dimensions. However, the standard s-SNOM technique lacks direct resolving ability along the vertical direction, therefore unable to provide full three-dimensional near-field responses. Here, we develop a reconstruction technique that enables s-SNOM to collect a three-dimensional response cube of near-field interaction. The technique also allows a new operational mode of s-SNOM based on the characteristic decay range of near-field interactions. As a demonstration, the bound near-field at the sides of a polaritonic boron nitride nanotube is revealed through the collection of the near-field response cube. The graphene boundary and discontinuities are revealed by the near-field decay range mapping. The reconstruction s-SNOM technique extends the capability of s-SNOM and is generally applicable for a wide range of nanoscale characterizations that are suitable for s-SNOM, such as characterizations of plasmonic and polaritonic nanostructures.

  4. Cerebral blood flow response to functional activation

    DEFF Research Database (Denmark)

    Paulson, Olaf B; Hasselbalch, Steen G; Rostrup, Egill

    2010-01-01

    Cerebral blood flow (CBF) and cerebral metabolic rate are normally coupled, that is an increase in metabolic demand will lead to an increase in flow. However, during functional activation, CBF and glucose metabolism remain coupled as they increase in proportion, whereas oxygen metabolism only...

  5. Computing the far field scattered or radiated by objects inside layered fluid media using approximate Green's functions.

    Science.gov (United States)

    Zampolli, Mario; Tesei, Alessandra; Canepa, Gaetano; Godin, Oleg A

    2008-06-01

    A numerically efficient technique is presented for computing the field radiated or scattered from three-dimensional objects embedded within layered acoustic media. The distance between the receivers and the object of interest is supposed to be large compared to the acoustic wavelength. The method requires the pressure and normal particle displacement on the surface of the object or on an arbitrary circumscribing surface, as an input, together with a knowledge of the layered medium Green's functions. The numerical integration of the full wave number spectral representation of the Green's functions is avoided by employing approximate formulas which are available in terms of elementary functions. The pressure and normal particle displacement on the surface of the object of interest, on the other hand, may be known by analytical or numerical means or from experiments. No restrictions are placed on the location of the object, which may lie above, below, or across the interface between the fluid media. The proposed technique is verified through numerical examples, for which the near field pressure and the particle displacement are computed via a finite-element method. The results are compared to validated reference models, which are based on the full wave number spectral integral Green's function.

  6. Hydrogen dynamics in Na3AlH6: A combined density functional theory and quasielastic neutron scattering study

    DEFF Research Database (Denmark)

    Voss, Johannes; Shi, Qing; Jacobsen, Hjalte Sylvest

    2007-01-01

    Understanding the elusive catalytic role of titanium-based additives on the reversible hydrogenation of complex hydrides is an essential step toward developing hydrogen storage materials for the transport sector. Improved bulk diffusion of hydrogen is one of the proposed effects of doping sodium...... alanate with TiCl3, and here we study hydrogen dynamics in doped and undoped Na3AlH6 using a combination of density functional theory calculations and quasielastic neutron scattering. The hydrogen dynamics is found to be vacancy mediated and dominated by localized jump events, whereas long-range bulk...... diffusion requires significant activation. The fraction of mobile hydrogen is found to be small for both undoped and doped Na3AlH6, even at 350 K, and improved hydrogen diffusion as a result of bulk-substituted titanium is found to be unlikely. We also propose that previously detected low-temperature point...

  7. Point defect dynamics in sodium aluminum hydrides - a combined quasielastic neutron scattering and density functional theory study

    DEFF Research Database (Denmark)

    Shi, Qing; Voss, Johannes; Jacobsen, H.S.

    2007-01-01

    we study hydrogen dynamics in undoped and TiCl3-doped samples of NaAlH4 and Na3AlH6 using a combination of density functional theory calculations and quasielastic neutron scattering. Hydrogen dynamics is found to be limited and mediated by hydrogen vacancies in both alanate phases, requiring...... an activation in excess of 0.3 eV. Even at 390 K, less than 1% of the hydrogen in NaAlH4 performs long range diffusion, and only localized hydrogen dynamics is observed in Na3AlH6. The effect of the TiCl3 dopant on hydrogen bulk diffusion is found to be negligible....

  8. ARES: automated response function code. Users manual. [HPGAM and LSQVM

    Energy Technology Data Exchange (ETDEWEB)

    Maung, T.; Reynolds, G.M.

    1981-06-01

    This ARES user's manual provides detailed instructions for a general understanding of the Automated Response Function Code and gives step by step instructions for using the complete code package on a HP-1000 system. This code is designed to calculate response functions of NaI gamma-ray detectors, with cylindrical or rectangular geometries.

  9. Excitation functions of proton-proton elastic scattering at intermediate energies

    Science.gov (United States)

    Scobel, W.; Dohrmann, F.; Bisplinghoff, J.; Hinterberger, F.; Scobel, W.; Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Bissel, T.; Bollmann, R.; Busch, M.; Büßer, K.; Cloth, P.; Danie, R.; Diehl, O.; Dohrmann, F.; Engelhardt, H. P.; Ernst, J.; Eversheim, P. D.; Felden, O.; Flammer, J.; Gasthuber, M.; Gebel, R.; Greiff, J.; Groß, A.; Groß-Hardt, R.; Hebbel, K.; Hinterberger, F.; Hüskes, T.; Jahn, R.; Koch, I.; Langkau, R.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuk, T.; Pfuff, M.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Schirm, N.; Schulz-Rojahn, M.; Schwarz, V.; Scobel, W.; Steinbeck, S.; Sterzenbach, G.; Thomas, S.; Trelle, H. J.; Walker, M.; Weise, E.; Wellinghausen, A.; Woller, K.; Ziegler, R.; EDDA Collaboration at COSY; EDDA Collaboration

    1998-03-01

    Excitation functions of proton-proton elastic cross sections have been measured in narrow momentum steps Δp = 28 MeV/c in the kinetic energy range from 0.5 to 2.5 GeV and the angular range 35° ≤ Θcm ≤ 90° with a detector providing ΔΘcm ≈ 1.4° resolution and 82% solid angle coverage. Measurements have been performed continuously during projectile acceleration in the Cooler Synchrotron COSY with an internal CH 2 fiber target; background corrections were derived from measurements with a carbon fiber target and from Monte Carlo simulations of inelastic pp contributions. Particular care was taken to monitor the luminosity as a function of beam energy. The results provide excitation functions and angular distributions of unprecedented precision and internal consistency. The measured cross sections are compared to recent phase shift analyses, and their impact on the present solution SM97 [1] is discussed.

  10. Adaptive Feeding behavior and functional responses in pelagic copepods

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Saiz, Enrico; Tiselius, Peter

    2018-01-01

    Zooplankton may modify their feeding behavior in response to prey availability and presence of predators with implications to populations of both predators and prey. Optimal foraging theory predicts that such responses result in a type II functional response for passive foragers and a type III re...

  11. A scatter model for parallel and converging beam SPECT based on the Klein-Nishina formula

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Z.J.; Frey, E.C.; Tsui, B.M.W. (Univ. of North Carolina, Chapel Hill, NC (United States))

    1994-08-01

    In this study, a scatter model is proposed for parallel-, fan-, and cone-beam SPECT imaging. In this model, a photon is allowed to be scattered only once, and the probability of scatter for given angle and energy is computed by using the Klein-Nishina formula. The detector is assumed to have perfect energy resolution. The scatter counts are computed for every projection bin. From the scatter counts, the scatter line source response function and scatter-to-primary ratio (SPR) are obtained. They agree well with those from Monte Carlo (MC) simulation including only single scattering, but deviate from those from full MC simulation including both single and multiple scattering. The deviation depends on the source depth within the medium. For a source depth of 6 cm, the difference of the scatter-to-primary ratio between the model and full MC simulation is less than 7%, while for a 21.6 cm source depth, the difference goes up to 27% for parallel-beam geometry and 32% for cone-beam geometry. Since scatter accounts for 20--40% of the total counts in most clinical studies, the scatter model yields a SPR accuracy that ranges from 3% to 12%. The scatter model provides an effective means to estimate the scatter response with reasonable accuracy, and can be used in developing scatter compensation techniques in parallel- and converging-beam SPECT.

  12. The coherent scattering function of the reptation model: simulations compared to theory

    NARCIS (Netherlands)

    A. Baumgärtner; U. Ebert (Ute); L. Schäfer

    2003-01-01

    textabstractWe present results of Monte Carlo simulations measuring the coherent structure function of a chain moving through an ordered lattice of fixed topological obstacles. Our computer experiments use chains up to 320 beads and cover a large range of wave vectors and a time range exceeding the

  13. Multisection transmission line scatter function theory for measurements of soil dielectric properties

    Science.gov (United States)

    Vector network analyzers measure both reflection (S11) and transmission (S21) functions, but S21 has not been used to estimate soil dielectric permittivity independently. The objectives of this study were to: (1) derive the mathematical model for S21 of a multisection transmission line, and (2) tes...

  14. The gated integration technique for the accurate measurement of the autocorrelation function of speckle intensities scattered from random phase screens

    Science.gov (United States)

    Zhang, Ningyu; Cheng, Chuanfu; Teng, Shuyun; Chen, Xiaoyi; Xu, Zhizhan

    2007-09-01

    A new approach based on the gated integration technique is proposed for the accurate measurement of the autocorrelation function of speckle intensities scattered from a random phase screen. The Boxcar used for this technique in the acquisition of the speckle intensity data integrates the photoelectric signal during its sampling gate open, and it repeats the sampling by a preset number, m. The average analog of the m samplings output by the Boxcar enhances the signal-to-noise ratio by √{m}, because the repeated sampling and the average make the useful speckle signals stable, while the randomly varied photoelectric noise is suppressed by 1/√{m}. In the experiment, we use an analog-to-digital converter module to synchronize all the actions such as the stepped movement of the phase screen, the repeated sampling, the readout of the averaged output of the Boxcar, etc. The experimental results show that speckle signals are better recovered from contaminated signals, and the autocorrelation function with the secondary maximum is obtained, indicating that the accuracy of the measurement of the autocorrelation function is greatly improved by the gated integration technique.

  15. Effect of scattered electrons on the ‘Magic Plate’ transmission array detector response

    Science.gov (United States)

    Alrowaili, Z. A.; Lerch, M.; Petasecca, M.; Carolan, M.; Rosenfeld, A.

    2017-02-01

    Transmission type detectors can provide a measure of the energy fluence and if they are real-time systems that do not significantly attenuate the radiation beam have a distinct advantage over the current method as Quality Assurance (QA) could in principle be done during the actual patient treatment. The use of diode arrays in QA holds much promise due to real-time operation and feedback when compared to other methods e.g. films which are not real-time. The goal of this work is to describe the characterization of the radiation response of a silicon diode array called the Magic Plate (MP) when operated in transmission mode (MPTM). The response linearity of MPTM was excellent (R2=1). When the MP was placed in linac block tray position; the change in PDD at phantom surface (SSD 100 cm) for a 10 × 10 cm2 was -0.037 %, -0.178 % and -0.949 % for 6 MV, 10 MV and 18 MV beams. Therefore, MP does not provide a significant increase in skin dose to the patient and the percentage depth doses showed an excellent agreement with and without MPTM for 6 MV, 10 MV and 18 MV beams.

  16. Buckling Response of Thick Functionally Graded Plates

    Directory of Open Access Journals (Sweden)

    BOUAZZA MOKHTAR

    2014-11-01

    Full Text Available In this paper, the buckling of a functionally graded plate is studied by using first order shear deformation theory (FSDT. The material properties of the plate are assumed to be graded continuously in the direction of thickness. The variation of the material properties follows a simple power-law distribution in terms of the volume fractions of constituents. The von Karman strains are used to construct the equilibrium equations of the plates subjected to two types of thermal loading, linear temperature rise and gradient through the thickness are considered. The governing equations are reduced to linear differential equation with boundary conditions yielding a simple solution procedure. In addition, the effects of temperature field, volume fraction distributions, and system geometric parameters are investigated. The results are compared with the results of the no shear deformation theory (classic plate theory, CPT.

  17. Structure factor of blends of solvent-free nanoparticle–organic hybrid materials: density-functional theory and small angle X-ray scattering

    KAUST Repository

    Yu, Hsiu-Yu

    2014-09-15

    © the Partner Organisations 2014. We investigate the static structure factor S(q) of solvent-free nanoparticle-organic hybrid materials consisting of silica nanocores and space-filling polyethylene glycol coronas using a density-functional theory and small angle X-ray scattering measurements. The theory considers a bidisperse suspension of hard spheres with different radii and tethered bead-spring oligomers with different grafting densities to approximate the polydispersity effects in experiments. The experimental systems studied include pure samples with different silica core volume fractions and the associated mean corona grafting densities, and blends with different mixing ratios of the pure samples, in order to introduce varying polydispersity of corona grafting density. Our scattering experiments and theory show that, compared to the hard-sphere suspension with the same core volume fraction, S(q) for pure samples exhibit both substantially smaller values at small q and stronger particle correlations corresponding to a larger effective hard core at large q, indicating that the tethered incompressible oligomers enforce a more uniform particle distribution, and the densely grafted brush gives rise to an additional exclusionary effect between the nanoparticles. According to the theory, polydispersity in the oligomer grafting density controls the deviation of S(q) from the monodisperse system at smaller q, and the interplay of the enhanced effective core size and the entropic attraction among the particles is responsible for complex variations in the particle correlations at larger q. The successful comparison between the predictions and the measurements for the blends further suggests that S(q) can be used to assess the uniformity of grafting density in polymer-grafted nanoparticle materials. This journal is

  18. Hemodynamic and Light-Scattering Changes of Rat Spinal Cord and Primary Somatosensory Cortex in Response to Innocuous and Noxious Stimuli

    Directory of Open Access Journals (Sweden)

    Ji-Wei He

    2015-09-01

    Full Text Available Neuroimaging technologies with an exceptional spatial resolution and noninvasiveness have become a powerful tool for assessing neural activity in both animals and humans. However, the effectiveness of neuroimaging for pain remains unclear partly because the neurovascular coupling during pain processing is not completely characterized. Our current work aims to unravel patterns of neurovascular parameters in pain processing. A novel fiber-optic method was used to acquire absolute values of regional oxy- (HbO and deoxy-hemoglobin concentrations, oxygen saturation rates (SO2, and the light-scattering coefficients from the spinal cord and primary somatosensory cortex (SI in 10 rats. Brief mechanical and electrical stimuli (ranging from innocuous to noxious intensities as well as a long-lasting noxious stimulus (formalin injection were applied to the hindlimb under pentobarbital anesthesia. Interhemispheric comparisons in the spinal cord and SI were used to confirm functional activation during sensory processing. We found that all neurovascular parameters showed stimulation-induced changes; however, patterns of changes varied with regions and stimuli. Particularly, transient increases in HbO and SO2 were more reliably attributed to brief stimuli, whereas a sustained decrease in SO2 was more reliably attributed to formalin. Only the ipsilateral SI showed delayed responses to brief stimuli. In conclusion, innocuous and noxious stimuli induced significant neurovascular responses at critical centers (e.g., the spinal cord and SI along the somatosensory pathway; however, there was no single response pattern (as measured by amplitude, duration, lateralization, decrease or increase that was able to consistently differentiate noxious stimuli. Our results strongly suggested that the neurovascular response patterns differ between brief and long-lasting noxious stimuli, and can also differ between the spinal cord and SI. Therefore, a use of multiple

  19. Calculations of band diagrams and low frequency dispersion relations of 2D periodic dielectric scatterers using broadband Green's function with low wavenumber extraction (BBGFL).

    Science.gov (United States)

    Tsang, Leung; Tan, Shurun

    2016-01-25

    The broadband Green's function with low wavenumber extraction (BBGFL) is applied to the calculations of band diagrams of two-dimensional (2D) periodic structures with dielectric scatterers. Periodic Green's functions of both the background and the scatterers are used to formulate the dual surface integral equations by approaching the surface of the scatterer from outside and inside the scatterer. The BBGFL are applied to both periodic Green's functions. By subtracting a low wavenumber component of the periodic Green's functions, the broadband part of the Green's functions converge with a small number of Bloch waves. The method of Moment (MoM) is applied to convert the surface integral equations to a matrix eigenvalue problem. Using the BBGFL, a linear eigenvalue problem is obtained with all the eigenmodes computed simultaneously giving the multiband results at a point in the Brillouin zone Numerical results are illustrated for the honeycomb structure. The results of the band diagrams are in good agreement with the planewave method and the Korringa Kohn Rostoker (KKR) method. By using the lowest band around the Γ point, the low frequency dispersion relations are calculated which also give the effective propagation constants and the effective permittivity in the low frequency limit.

  20. Single and multiple scattering XAFS Debye-Waller factors for crystalline materials using periodic Density Functional Theory

    Energy Technology Data Exchange (ETDEWEB)

    Dimakis, N; Mion, T [Department of Physics and Geology, University of Texas-Pan American, Edinburg, TX 78539 (United States); Bunker, G, E-mail: dimakis@utpa.ed [Department of Biological Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616 (United States)

    2009-11-15

    We present an accurate and efficient technique for calculating thermal X-ray absorption fine structure (XAFS) Debye-Waller factors (DWFs) applicable to crystalline materials. Using Density Functional Theory on a 3x3x3 supercell pattern of MnO structure, under the nonlocal hybrid B3LYP functional paired with Gaussian local basis sets, we obtain the normal mode eigenfrequencies and eigenvectors; these parameters are in turn used to calculate single and multiple scattering XAFS DWFs. The DWFs obtained via this technique are temperature dependent expressions and can be used to substantially reduce the number of fitting parameters, when experimental spectra are fitted with a hypothetical structure. The size of the supercell size limits the R-space range that these parameters could be used. Therefore corresponding DWFs for paths outside of this range are calculated using the correlated Debye model. Our method is compared with prior cluster calculations and with corresponding values obtained from fitting experimental XAFS spectra on manganosite with simulated spectra.

  1. Simulation and Analysis of Spectral Response Function and Bandwidth of Spectrometer

    Directory of Open Access Journals (Sweden)

    Zhenyu Gao

    2016-01-01

    Full Text Available A simulation method for acquiring spectrometer’s Spectral Response Function (SRF based on Huygens Point Spread Function (PSF is suggested. Taking into account the effects of optical aberrations and diffraction, the method can obtain the fine SRF curve and corresponding spectral bandwidth at any nominal wavelength as early as in the design phase. A prism monochromator is proposed for illustrating the simulation procedure. For comparison, a geometrical ray-tracing method is also provided, with bandwidth deviations varying from 5% at 250 nm to 25% at 2400 nm. Further comparison with reported experiments shows that the areas of the SRF profiles agree to about 1%. However, the weak scattered background light on the level of 10−4 to 10−5 observed by experiment could not be covered by this simulation. This simulation method is a useful tool for forecasting the performance of an underdesigned spectrometer.

  2. Purely bianisotropic scatterers

    Science.gov (United States)

    Albooyeh, M.; Asadchy, V. S.; Alaee, R.; Hashemi, S. M.; Yazdi, M.; Mirmoosa, M. S.; Rockstuhl, C.; Simovski, C. R.; Tretyakov, S. A.

    2016-12-01

    The polarization response of molecules or meta-atoms to external electric and magnetic fields, which defines the electromagnetic properties of materials, can either be direct (electric field induces electric moment and magnetic field induces magnetic moment) or indirect (magnetoelectric coupling in bianisotropic scatterers). Earlier studies suggest that there is a fundamental bound on the indirect response of all passive scatterers: It is believed to be always weaker than the direct one. In this paper, we prove that there exist scatterers which overcome this bound substantially. Moreover, we show that the amplitudes of electric and magnetic polarizabilities can be negligibly small as compared to the magnetoelectric coupling coefficients. However, we prove that if at least one of the direct-excitation coefficients vanishes, magnetoelectric coupling effects in passive scatterers cannot exist. Our findings open a way to a new class of electromagnetic scatterers and composite materials.

  3. Gamma strength functions and level densities from high-resolution inelastic proton scattering at very forward angles

    Directory of Open Access Journals (Sweden)

    Bassauer Sergej

    2017-01-01

    Full Text Available Inelastic proton scattering at energies of a few 100 MeV and forward angles including 0∘ provides a novel method to measure gamma strength functions (GSF in nuclei in an energy range of about 5–23 MeV. The experiments provide not only the E1 but also the M1 part of the GSF. The latter is poorly known in heavy nuclei. A case study of 208Pb indicates that the systematics proposed for the M1-GSF in RIPL-3 needs to be substantially revised. Comparison with gamma decay data (e.g. from the Oslo method allows to test the generalised Brink-Axel (BA hypothesis in the energy region of the pygmy dipole resonance (PDR crucial for the modelling of (n,γ and (γ,n reactions in astrophysical reaction networks. A fluctuation analysis of the high-resolution data also provides a direct measure of level densities in the energy region well above the neutron threshold, where hardly any experimental information is available.

  4. Gamma strength functions and level densities from high-resolution inelastic proton scattering at very forward angles

    Science.gov (United States)

    Bassauer, Sergej; Neumann-Cosel, Peter von; Tamii, Atsushi

    2017-09-01

    Inelastic proton scattering at energies of a few 100 MeV and forward angles including 0∘ provides a novel method to measure gamma strength functions (GSF) in nuclei in an energy range of about 5-23 MeV. The experiments provide not only the E1 but also the M1 part of the GSF. The latter is poorly known in heavy nuclei. A case study of 208Pb indicates that the systematics proposed for the M1-GSF in RIPL-3 needs to be substantially revised. Comparison with gamma decay data (e.g. from the Oslo method) allows to test the generalised Brink-Axel (BA) hypothesis in the energy region of the pygmy dipole resonance (PDR) crucial for the modelling of (n,γ) and (γ,n) reactions in astrophysical reaction networks. A fluctuation analysis of the high-resolution data also provides a direct measure of level densities in the energy region well above the neutron threshold, where hardly any experimental information is available.

  5. Time-domain Kirchhoff model for acoustic scattering from an impedance polygon facet.

    Science.gov (United States)

    Lee, Keunhwa; Seong, Woojae

    2009-07-01

    Kirchhoff formula for an impedance polygon facet is given in the time domain. The derived formula is expressed as a summation of the transient analytic functions and generalized functions and represents an impulse response of the impedance polygon facet. Current formula can be applied to transient scattering analysis of underwater objects such as fish and submarine, or rough surface in the geometrical scattering region.

  6. Solar Wind Halo Formation by the Scattering of the Strahl via Direct Cluster/PEACE Observations of the 3D Velocity Distribution Function

    Science.gov (United States)

    Figueroa-Vinas, Adolfo; Gurgiolo, Chris A.; Nieves-Chinchilla, Teresa; Goldstein, Melvyn L.

    2010-01-01

    It has been suggested by a number of authors that the solar wind electron halo can be formed by the scattering of the strahl. On frequent occasions we have observed in electron angular skymaps (Phi/Theta-plots) of the electron 3D velocity distribution functions) a bursty-filament of particles connecting the strahl to the solar wind core-halo. These are seen over a very limited energy range. When the magnetic field is well off the nominal solar wind flow direction such filaments are inconsistent with any local forces and are probably the result of strong scattering. Furthermore, observations indicates that the strahl component is frequently and significantly anisotropic (Tper/Tpal approx.2). This provides a possible free energy source for the excitation of whistler waves as a possible scattering mechanism. The empirical observational evidence between the halo and the strahl suggests that the strahl population may be, at least in part, the source of the halo component.

  7. Modelling Hyperboloid Sound Scattering

    DEFF Research Database (Denmark)

    Burry, Jane; Davis, Daniel; Peters, Brady

    2011-01-01

    The Responsive Acoustic Surfaces workshop project described here sought new understandings about the interaction between geometry and sound in the arena of sound scattering. This paper reports on the challenges associated with modelling, simulating, fabricating and measuring this phenomenon using...... both physical and digital models at three distinct scales. The results suggest hyperboloid geometry, while difficult to fabricate, facilitates sound scattering.......The Responsive Acoustic Surfaces workshop project described here sought new understandings about the interaction between geometry and sound in the arena of sound scattering. This paper reports on the challenges associated with modelling, simulating, fabricating and measuring this phenomenon using...

  8. Linear response of homogeneous nuclear matter with energy density functionals

    Energy Technology Data Exchange (ETDEWEB)

    Pastore, A. [Institut d’Astronomie et d’Astrophysique, CP 226, Université Libre de Bruxelles, B-1050 Bruxelles (Belgium); Davesne, D., E-mail: davesne@ipnl.in2p3.fr [Institut de Physique Nucléaire de Lyon, CNRS-IN2P3, UMR 5822, Université Lyon 1, F-69622 Villeurbanne (France); Navarro, J. [IFIC (CSIC University of Valencia), Apdo. Postal 22085, E-46071 Valencia (Spain)

    2015-03-01

    Response functions of infinite nuclear matter with arbitrary isospin asymmetry are studied in the framework of the random phase approximation. The residual interaction is derived from a general nuclear Skyrme energy density functional. Besides the usual central, spin–orbit and tensor terms it could also include other components as new density-dependent terms or three-body terms. Algebraic expressions for the response functions are obtained from the Bethe–Salpeter equation for the particle–hole propagator. Applications to symmetric nuclear matter, pure neutron matter and asymmetric nuclear matter are presented and discussed. Spin–isospin strength functions are analyzed for varying conditions of density, momentum transfer, isospin asymmetry, and temperature for some representative Skyrme functionals. Particular attention is paid to the discussion of instabilities, either real or unphysical, which could manifest in finite nuclei.

  9. Science in Emergency Response at CDC: Structure and Functions

    Science.gov (United States)

    Rose, Dale A.; Ghiya, Neelam D.

    2017-01-01

    Recent high-profile activations of the US Centers for Disease Control and Prevention (CDC) Emergency Operations Center (EOC) include responses to the West African Ebola and Zika virus epidemics. Within the EOC, emergency responses are organized according to the Incident Management System, which provides a standardized structure and chain of command, regardless of whether the EOC activation occurs in response to an outbreak, natural disaster, or other type of public health emergency. By embedding key scientific roles, such as the associate director for science, and functions within a Scientific Response Section, the current CDC emergency response structure ensures that both urgent and important science issues receive needed attention. Key functions during emergency responses include internal coordination of scientific work, data management, information dissemination, and scientific publication. We describe a case example involving the ongoing Zika virus response that demonstrates how the scientific response structure can be used to rapidly produce high-quality science needed to answer urgent public health questions and guide policy. Within the context of emergency response, longer-term priorities at CDC include both streamlining administrative requirements and funding mechanisms for scientific research. PMID:28892452

  10. Science in Emergency Response at CDC: Structure and Functions.

    Science.gov (United States)

    Iskander, John; Rose, Dale A; Ghiya, Neelam D

    2017-09-01

    Recent high-profile activations of the US Centers for Disease Control and Prevention (CDC) Emergency Operations Center (EOC) include responses to the West African Ebola and Zika virus epidemics. Within the EOC, emergency responses are organized according to the Incident Management System, which provides a standardized structure and chain of command, regardless of whether the EOC activation occurs in response to an outbreak, natural disaster, or other type of public health emergency. By embedding key scientific roles, such as the associate director for science, and functions within a Scientific Response Section, the current CDC emergency response structure ensures that both urgent and important science issues receive needed attention. Key functions during emergency responses include internal coordination of scientific work, data management, information dissemination, and scientific publication. We describe a case example involving the ongoing Zika virus response that demonstrates how the scientific response structure can be used to rapidly produce high-quality science needed to answer urgent public health questions and guide policy. Within the context of emergency response, longer-term priorities at CDC include both streamlining administrative requirements and funding mechanisms for scientific research.

  11. The non-linear terahertz response of hot electrons in low-dimensional semiconductor superlattices: Suppression of the polar-optical phonon scattering

    Science.gov (United States)

    Ignatov, Anatoly A.

    2017-10-01

    We study the response of low-dimensional semiconductor superlattices to strong terahertz fields on condition of a strong suppression of inelastic scattering processes of electrons caused by the polar-optical phonons. For our study, we employ a balance equations approach, which allows investigating the response of the superlattices to strong terahertz fields taking account of both the inelastic and the strongly pronounced elastic scattering of electrons. Our approach provides a way to analyze the influence of the Bloch dynamics of electrons in a superlattice miniband side by side with the effects of the electron heating on the magnitude and the frequency dependence of a superlattice current responsivity in the terahertz frequency band. Our study shows that the suppression of the inelastic scattering caused either by a reduction of the superlattice dimensionality by lateral quantization or by a strong magnetic field application can give rise to a huge enhancement of the current responsivity. This enhancement can be interpreted in terms of the well pronounced electronic bolometric effect occurring due to the efficient electron heating in the low-dimensional superlattices by the incident terahertz fields.

  12. Diffuse scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kostorz, G. [Eidgenoessische Technische Hochschule, Angewandte Physik, Zurich (Switzerland)

    1996-12-31

    While Bragg scattering is characteristic for the average structure of crystals, static local deviations from the average lattice lead to diffuse elastic scattering around and between Bragg peaks. This scattering thus contains information on the occupation of lattice sites by different atomic species and on static local displacements, even in a macroscopically homogeneous crystalline sample. The various diffuse scattering effects, including those around the incident beam (small-angle scattering), are introduced and illustrated by typical results obtained for some Ni alloys. (author) 7 figs., 41 refs.

  13. Function-specific response to depletion of microbial diversity.

    Science.gov (United States)

    Peter, Hannes; Beier, Sara; Bertilsson, Stefan; Lindström, Eva S; Langenheder, Silke; Tranvik, Lars J

    2011-02-01

    Recent meta-analyses suggest that ecosystem functioning increases with biodiversity, but contradictory results have been presented for some microbial functions. Moreover, observations of only one function underestimate the functional role of diversity because of species-specific trade-offs in the ability to carry out different functions. We examined multiple functions in batch cultures of natural freshwater bacterial communities with different richness, achieved by a dilution-to-extinction approach. Community composition was assessed by molecular fingerprinting of 16S rRNA and chitinase genes, representing the total community and a trait characteristic for a functional group, respectively. Richness was positively related to abundance and biomass, negatively correlated to cell volumes and unrelated to maximum intrinsic growth rate. The response of chitin and cellulose degradation rates depended on the presence of a single phylotype. We suggest that species identity and community composition rather than richness matters for specific microbial processes.

  14. Mitochondrial respiration controls lysosomal function during inflammatory T cell responses

    Science.gov (United States)

    Baixauli, Francesc; Acín-Pérez, Rebeca; Villarroya-Beltrí, Carolina; Mazzeo, Carla; Nuñez-Andrade, Norman; Gabandé-Rodriguez, Enrique; Dolores Ledesma, Maria; Blázquez, Alberto; Martin, Miguel Angel; Falcón-Pérez, Juan Manuel; Redondo, Juan Miguel; Enríquez, Jose Antonio; Mittelbrunn, Maria

    2016-01-01

    Summary The endolysosomal system is critical for the maintenance of cellular homeostasis. However, how endolysosomal compartment is regulated by mitochondrial function is largely unknown. We have generated a mouse model with defective mitochondrial function in CD4+ T lymphocytes by genetic deletion of the mitochondrial transcription factor A (Tfam). Mitochondrial respiration-deficiency impairs lysosome function, promotes p62 and sphingomyelin accumulation and disrupts endolysosomal trafficking pathways and autophagy, thus linking a primary mitochondrial dysfunction to a lysosomal storage disorder. The impaired lysosome function in Tfam-deficient cells subverts T cell differentiation toward pro-inflammatory subsets and exacerbates the in vivo inflammatory response. Restoration of NAD+ levels improves lysosome function and corrects the inflammatory defects in Tfam-deficient T cells. Our results uncover a mechanism by which mitochondria regulate lysosome function to preserve T cell differentiation and effector functions, and identify novel strategies for intervention in mitochondrial-related diseases. PMID:26299452

  15. Population dynamics and mutualism: Functional responses of benefits and costs

    Science.gov (United States)

    Holland, J. Nathaniel; DeAngelis, Donald L.; Bronstein, Judith L.

    2002-01-01

    We develop an approach for studying population dynamics resulting from mutualism by employing functional responses based on density‐dependent benefits and costs. These functional responses express how the population growth rate of a mutualist is modified by the density of its partner. We present several possible dependencies of gross benefits and costs, and hence net effects, to a mutualist as functions of the density of its partner. Net effects to mutualists are likely a monotonically saturating or unimodal function of the density of their partner. We show that fundamental differences in the growth, limitation, and dynamics of a population can occur when net effects to that population change linearly, unimodally, or in a saturating fashion. We use the mutualism between senita cactus and its pollinating seed‐eating moth as an example to show the influence of different benefit and cost functional responses on population dynamics and stability of mutualisms. We investigated two mechanisms that may alter this mutualism's functional responses: distribution of eggs among flowers and fruit abortion. Differences in how benefits and costs vary with density can alter the stability of this mutualism. In particular, fruit abortion may allow for a stable equilibrium where none could otherwise exist.

  16. Local and linear chemical reactivity response functions at finite temperature in density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Franco-Pérez, Marco, E-mail: francopj@mcmaster.ca, E-mail: ayers@mcmaster.ca, E-mail: jlgm@xanum.uam.mx, E-mail: avela@cinvestav.mx [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, México, D.F. 09340 (Mexico); Ayers, Paul W., E-mail: francopj@mcmaster.ca, E-mail: ayers@mcmaster.ca, E-mail: jlgm@xanum.uam.mx, E-mail: avela@cinvestav.mx [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Gázquez, José L., E-mail: francopj@mcmaster.ca, E-mail: ayers@mcmaster.ca, E-mail: jlgm@xanum.uam.mx, E-mail: avela@cinvestav.mx [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, México, D.F. 09340 (Mexico); Vela, Alberto, E-mail: francopj@mcmaster.ca, E-mail: ayers@mcmaster.ca, E-mail: jlgm@xanum.uam.mx, E-mail: avela@cinvestav.mx [Departamento de Química, Centro de Investigación y de Estudios Avanzados (Cinvestav), Av. Instituto Politécnico Nacional 2508, México, D.F. 07360 (Mexico)

    2015-12-28

    We explore the local and nonlocal response functions of the grand canonical potential density functional at nonzero temperature. In analogy to the zero-temperature treatment, local (e.g., the average electron density and the local softness) and nonlocal (e.g., the softness kernel) intrinsic response functions are defined as partial derivatives of the grand canonical potential with respect to its thermodynamic variables (i.e., the chemical potential of the electron reservoir and the external potential generated by the atomic nuclei). To define the local and nonlocal response functions of the electron density (e.g., the Fukui function, the linear density response function, and the dual descriptor), we differentiate with respect to the average electron number and the external potential. The well-known mathematical relationships between the intrinsic response functions and the electron-density responses are generalized to nonzero temperature, and we prove that in the zero-temperature limit, our results recover well-known identities from the density functional theory of chemical reactivity. Specific working equations and numerical results are provided for the 3-state ensemble model.

  17. The Synthesis of Structural Responses Using Experimentally Measured Frequency Response Functions and Field Test Data

    Energy Technology Data Exchange (ETDEWEB)

    CAP,JEROME S.; NELSON,CURTIS F.

    2000-11-17

    This paper presents an analysis technique used to generate the structural response at locations not measured during the ejection of a captive-carried store. The ejection shock event is complicated by the fact that forces may be imparted to the store at eight distinct locations. The technique derives forcing functions by combining the initial field test data for a limited number of measurement locations with Frequency Response Functions (FRFs) measured using a traditional modal-type impact (tap) test at the same locations. The derived forcing functions were then used with tap test FRFs measured at additional locations of interest to produce the desired response data.

  18. Response variance in functional maps: neural darwinism revisited.

    Directory of Open Access Journals (Sweden)

    Hirokazu Takahashi

    Full Text Available The mechanisms by which functional maps and map plasticity contribute to cortical computation remain controversial. Recent studies have revisited the theory of neural Darwinism to interpret the learning-induced map plasticity and neuronal heterogeneity observed in the cortex. Here, we hypothesize that the Darwinian principle provides a substrate to explain the relationship between neuron heterogeneity and cortical functional maps. We demonstrate in the rat auditory cortex that the degree of response variance is closely correlated with the size of its representational area. Further, we show that the response variance within a given population is altered through training. These results suggest that larger representational areas may help to accommodate heterogeneous populations of neurons. Thus, functional maps and map plasticity are likely to play essential roles in Darwinian computation, serving as effective, but not absolutely necessary, structures to generate diverse response properties within a neural population.

  19. Response variance in functional maps: neural darwinism revisited.

    Science.gov (United States)

    Takahashi, Hirokazu; Yokota, Ryo; Kanzaki, Ryohei

    2013-01-01

    The mechanisms by which functional maps and map plasticity contribute to cortical computation remain controversial. Recent studies have revisited the theory of neural Darwinism to interpret the learning-induced map plasticity and neuronal heterogeneity observed in the cortex. Here, we hypothesize that the Darwinian principle provides a substrate to explain the relationship between neuron heterogeneity and cortical functional maps. We demonstrate in the rat auditory cortex that the degree of response variance is closely correlated with the size of its representational area. Further, we show that the response variance within a given population is altered through training. These results suggest that larger representational areas may help to accommodate heterogeneous populations of neurons. Thus, functional maps and map plasticity are likely to play essential roles in Darwinian computation, serving as effective, but not absolutely necessary, structures to generate diverse response properties within a neural population.

  20. The response of electrostatic probes via the λ-function

    DEFF Research Database (Denmark)

    Rerup, T.O.; Crichton, George C; McAllister, Iain Wilson

    1994-01-01

    The response of an electrostatic probe is examined with reference to a planar spacer. The study involves the numerical calculation of the probe λ-function, from which response-related characteristic parameters can be derived. These parameters enable the probe detection sensitivity and spatial...... selectivity to be quantitatively assessed. Evaluation is undertaken with reference to spacer thickness, dielectric permittivity and the proximity of the spacer to other electrodes...

  1. Functional response of staging semipalmated sandpipers feeding on burrowing amphipods.

    Science.gov (United States)

    Beauchamp, Guy

    2009-09-01

    Despite its fundamental relevance to many ecological processes in predator-prey relationships, the functional response, which relates predator intake rate to prey density, remains difficult to document in the field. Here, I document the functional response of semipalmated sandpipers (Calidris pusilla) foraging on a burrowing amphipod Corophium volutator during three field seasons at the peak of fall migration in the upper Bay of Fundy (New Brunswick, Canada). I gathered data during the ebbing tide when all sandpipers are highly motivated to feed after a lengthy hide-tide fast. As birds follow the receding tideline, foragers encounter prey at different densities and do not aggregate in the richest food patches. Results show that intake rate increased at a decreasing rate with Corophium density, yielding a type II functional response typical of many shorebird species. Intake rate decreased in the later stages of migration stopover at a time where preferred prey items have been shown to occur at lower densities due to prior depletion. At this period of lower prey availability, intake rate also decreased with sandpiper density providing evidence for interference at low prey density. The results illustrate the fact that the functional response may not be unique but instead vary as a function of the type of competitive relationship among foragers.

  2. Functional connectivity correlates of response inhibition impairment in anorexia nervosa.

    Science.gov (United States)

    Collantoni, Enrico; Michelon, Silvia; Tenconi, Elena; Degortes, Daniela; Titton, Francesca; Manara, Renzo; Clementi, Maurizio; Pinato, Claudia; Forzan, Monica; Cassina, Matteo; Santonastaso, Paolo; Favaro, Angela

    2016-01-30

    Anorexia nervosa (AN) is a disorder characterized by high levels of cognitive control and behavioral perseveration. The present study aims at exploring inhibitory control abilities and their functional connectivity correlates in patients with AN. Inhibitory control - an executive function that allows the realization of adaptive behavior according to environmental contingencies - has been assessed by means of the Stop-Signal paradigm. The study involved 155 patients with lifetime AN and 102 healthy women. A subsample underwent resting-state functional magnetic resonance imaging and was genotyped for COMT and 5-HTTLPR polymorphisms. AN patients showed an impaired response inhibition and a disruption of the functional connectivity of the ventral attention circuit, a neural network implicated in behavioral response when a stimulus occurs unexpected. The 5-HTTLPR genotype appears to significantly interact with the functional connectivity of ventral attention network in explaining task performance in both patients and controls, suggesting a role of the serotoninergic system in mechanisms of response selection. The disruption of the ventral attention network in patients with AN suggests lower efficiency of bottom-up signal filtering, which might be involved in difficulties to adapt behavioral responses to environmental needs. Our findings deserve further research to confirm their scientific and therapeutic implications. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Response function of semiconductor detectors, Ge and Si(Li); Funcao resposta de detectores semicondutores, Ge e Si(Li)

    Energy Technology Data Exchange (ETDEWEB)

    Zevallos Chavez, Juan Yury

    2003-07-01

    The Response Function (RF) for Ge and Si(Li) semiconductor detectors was obtained. The RF was calculated for five detectors, four Hp Ge with active volumes of 89 cm{sup 3} , 50 cm{sup 3} , 8 cm{sup 3} and 5 cm{sup 3}, and one Si(Li) with 0.143 cm{sup 3} of active volume. The interval of energy studied ranged from 6 keV up to 1.5 MeV. Two kinds of studies were done in this work. The first one was the RF dependence with the detection geometry. Here the calculation of the RF for a geometry named as simple and an extrapolation of that RF, were both done. The extrapolation process analyzed both, spectra obtained with a shielding geometry and spectra where the source-detector distance was modified. The second one was the RF dependence with the detection electronics. This study was done varying the shaping time of the pulse in the detection electronics. The purpose was to verify the effect of the ballistic deficit in the resolution of the detector. This effect was not observed. The RF components that describe the region of the total absorption of the energy of the incident photons, and the partial absorption of this energy, were both treated. In particular, empirical functions were proposed for the treatment of both, the multiple scattering originated in the detector (crystal), and the photon scattering originated in materials of the neighborhood of the crystal. Another study involving Monte Carlo simulations was also done in order to comprehend the photon scattering structures produced in an iron shield. A deconvolution method is suggested, for spectra related to scattered radiation in order to assess the dose delivered to the scatterer. (author)

  4. Functional Relations Modulate the Responsiveness to Affordances Despite the Impact of Conflicting Stimulus–Response Mappings

    Directory of Open Access Journals (Sweden)

    Roberta Vastano

    2017-11-01

    Full Text Available The study investigated how conflicting stimulus–response mappings influenced affordance processing given a manipulation of the functional relations. Participants performed a task involving consistent–inconsistent stimulus–response mappings: Implicit Relational Assessment Procedure (IRAP. They were instructed to confirm or to deny a relation between words and tool-objects (consistent blocks or to provide non-conventional responses (inconsistent blocks. The relations between stimuli could functionally match (e.g., Kitchen – Spatula or not (e.g., Kitchen – Hammer, as well as the spatial relations (e.g., a match or a mismatch between participants’ hand response and the tool-object orientation. The results showed faster reaction times (RTs when functional relations between stimuli matched both in consistent and inconsistent blocks. Differences in RTs and accuracy between consistent and inconsistent blocks were only found when the functional relation between stimuli matched. No modulation of the performance was observed for mismatching functional relations and spatial relations between blocks. These results support the hypothesis that the responsiveness to affordances is strongly modulated by matching functional relations, despite the impact of conflicting stimulus–response mappings.

  5. Functional Relations Modulate the Responsiveness to Affordances Despite the Impact of Conflicting Stimulus-Response Mappings.

    Science.gov (United States)

    Vastano, Roberta; Finn, Martin; Barnes-Holmes, Dermot

    2017-01-01

    The study investigated how conflicting stimulus-response mappings influenced affordance processing given a manipulation of the functional relations. Participants performed a task involving consistent-inconsistent stimulus-response mappings: Implicit Relational Assessment Procedure (IRAP). They were instructed to confirm or to deny a relation between words and tool-objects (consistent blocks) or to provide non-conventional responses (inconsistent blocks). The relations between stimuli could functionally match (e.g., Kitchen - Spatula) or not (e.g., Kitchen - Hammer), as well as the spatial relations (e.g., a match or a mismatch between participants' hand response and the tool-object orientation). The results showed faster reaction times (RTs) when functional relations between stimuli matched both in consistent and inconsistent blocks. Differences in RTs and accuracy between consistent and inconsistent blocks were only found when the functional relation between stimuli matched. No modulation of the performance was observed for mismatching functional relations and spatial relations between blocks. These results support the hypothesis that the responsiveness to affordances is strongly modulated by matching functional relations, despite the impact of conflicting stimulus-response mappings.

  6. Functional Relations Modulate the Responsiveness to Affordances Despite the Impact of Conflicting Stimulus–Response Mappings

    Science.gov (United States)

    Vastano, Roberta; Finn, Martin; Barnes-Holmes, Dermot

    2017-01-01

    The study investigated how conflicting stimulus–response mappings influenced affordance processing given a manipulation of the functional relations. Participants performed a task involving consistent–inconsistent stimulus–response mappings: Implicit Relational Assessment Procedure (IRAP). They were instructed to confirm or to deny a relation between words and tool-objects (consistent blocks) or to provide non-conventional responses (inconsistent blocks). The relations between stimuli could functionally match (e.g., Kitchen – Spatula) or not (e.g., Kitchen – Hammer), as well as the spatial relations (e.g., a match or a mismatch between participants’ hand response and the tool-object orientation). The results showed faster reaction times (RTs) when functional relations between stimuli matched both in consistent and inconsistent blocks. Differences in RTs and accuracy between consistent and inconsistent blocks were only found when the functional relation between stimuli matched. No modulation of the performance was observed for mismatching functional relations and spatial relations between blocks. These results support the hypothesis that the responsiveness to affordances is strongly modulated by matching functional relations, despite the impact of conflicting stimulus–response mappings. PMID:29163319

  7. Excitation functions of the analyzing power in elastic proton-proton scattering from 0.45 to 2.5 GeV

    Science.gov (United States)

    Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Büßer, K.; Busch, M.; Colberg, T.; Demirörs, L.; Engelhardt, H. P.; Eversheim, P. D.; Eyser, K. O.; Felden, O.; Gebel, R.; Glende, M.; Greiff, J.; Hinterberger, F.; Jonas, E.; Krause, H.; Lindemann, T.; Lindlein, J.; Lorentz, B.; Maier, R.; Maschuw, R.; Meinerzhagen, A.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Schirm, N.; Schwarz, V.; Scobel, W.; Trelle, H.-J.; Ulbrich, K.; Weise, E.; Wellinghausen, A.; Ziegler, R.

    2005-02-01

    Excitation functions AN(plab,Θc.m.) of the analyzing power in elastic proton-proton scattering have been measured in an internal target experiment at the Cooler Synchrotron COSY with an unpolarized proton beam and a polarized atomic hydrogen target. Data were taken continuously during the acceleration and deceleration for proton kinetic energies Tlab (momenta plab) between 0.45 and 2.5 GeV (1.0 and 3.3 GeV/c) and scattering angles 30 ° ⩽ Θc.m. ⩽ 90°. The results provide excitation functions and angular distributions of high precision and internal consistency. The data can be used as calibration standard between 0.45 and 2.5 GeV. They have significant impact on phase shift solutions, in particular on the spin triplet phase shifts between 1.0 and 1.8 GeV.

  8. Functional Relations Modulate the Responsiveness to Affordances Despite the Impact of Conflicting Stimulus–Response Mappings

    OpenAIRE

    Roberta Vastano; Martin Finn; Dermot Barnes-Holmes

    2017-01-01

    The study investigated how conflicting stimulus–response mappings influenced affordance processing given a manipulation of the functional relations. Participants performed a task involving consistent–inconsistent stimulus–response mappings: Implicit Relational Assessment Procedure (IRAP). They were instructed to confirm or to deny a relation between words and tool-objects (consistent blocks) or to provide non-conventional responses (inconsistent blocks). The relations between stimuli could fu...

  9. Functional relations modulate the responsiveness to affordances despite the impact of conflicting stimulus-response mappings

    OpenAIRE

    Vastano, Roberta; Finn, Martin; Barnes-Holmes, Patrick Michael Dermot

    2017-01-01

    The study investigated how conflicting stimulus-response mappings influenced affordance processing given a manipulation of the functional relations. Participants performed a task involving consistent-inconsistent stimulus-response mappings: Implicit Relational Assessment Procedure (IRAP). They were instructed to confirm or to deny a relation between words and tool-objects (consistent blocks) or to provide non-conventional responses (inconsistent blocks). The relations between stimuli could fu...

  10. Functional response of Xylocoris falvipes , a biological control agent ...

    African Journals Online (AJOL)

    The warehouse pirate bug Xylocoris falvipes is an opportunist predator of many stored product insect pests. Its functional response in relationship with variable densities of prey appears as the Holling\\'s type II model. The predator X. falvipes, collected within small holder granaries in Mayo Danay division in the far North ...

  11. Ventilatory functions response to breathing training versus aerobic ...

    African Journals Online (AJOL)

    EL-HAKIM

    Egypt J Pediatr Allergy Immunol 2012;10(1):33-37. 33. Ventilatory functions response to breathing training versus aerobic training in asthmatic children. INTRODUCTION ... as anxiety, light headedness, and fatigue4. Many previous ... Objective: To compare the effects of a program of breathing training and aerobic training ...

  12. Functionalized mesoporous silica nanoparticles for stimuli-responsive and targeted

    Energy Technology Data Exchange (ETDEWEB)

    Knezevic, Nikola [Iowa State Univ., Ames, IA (United States)

    2009-12-15

    Construction of functional supramolecular nanoassemblies has attracted great deal of attention in recent years for their wide spectrum of practical applications. Mesoporous silica nanoparticles (MSN) in particular were shown to be effective scaffolds for the construction of drug carriers, sensors and catalysts. Herein, we describe the synthesis and characterization of stimuli-responsive, controlled release MSN-based assemblies for drug delivery.

  13. Cortisol stress responses and children's behavioral functioning at school

    NARCIS (Netherlands)

    Simons, S.S.H.; Cillessen, A.H.N.; Weerth, C. de

    2017-01-01

    The present study investigated whether cortisol stress responses of 6-year-olds were associated with their behavioral functioning at school. Additionally, the moderating role of stress in the family environment was examined. To this end, 149 healthy children (Mage = 6.09 years; 70 girls)

  14. Helping as a Function of Empathic Responses and Sociopathy.

    Science.gov (United States)

    Marks, Edward L.; And Others

    1982-01-01

    Investigated helping as a function of empathic anxiety (anxiety in response to modeled distress) and individual differences in sociopathic tendencies. Results indicated modeled distress produces increases in anxiety which are positively associated with helping and sociopathic individuals are less likely to help than are nonsociopathic individuals.…

  15. Functional MRI of food-induced brain responses

    NARCIS (Netherlands)

    Smeets, P.A.M.

    2006-01-01

    The ultimate goal of this research was to find central biomarkers of satiety, i.e., physiological measures in the brain that relate to subjectively rated appetite, actual food intake, or both. This thesis describes the changes in brain activity in response to food stimuli as measured by functional

  16. Response to "Rotational velocity autocorrelation function of interacting Brownian particles"

    NARCIS (Netherlands)

    Lowe, C.P.; Hagen, M. H. J.; Frenkel, D.

    2001-01-01

    Comment on "Response to ‘Rotational velocity autocorrelation function of interacting Brownian particles’", Referred to by: Physica A: Statistical Mechanics and its Applications, Volume 297, Issues 1-2, 1 August 2001, Pages 115-116. B. Cichocki, and B. U. Felderhof

  17. Semiparametric Item Response Functions in the Context of Guessing

    Science.gov (United States)

    Falk, Carl F.; Cai, Li

    2016-01-01

    We present a logistic function of a monotonic polynomial with a lower asymptote, allowing additional flexibility beyond the three-parameter logistic model. We develop a maximum marginal likelihood-based approach to estimate the item parameters. The new item response model is demonstrated on math assessment data from a state, and a computationally…

  18. Functional analysis of molecular interactions in synthetic auxin response circuits.

    Science.gov (United States)

    Pierre-Jerome, Edith; Moss, Britney L; Lanctot, Amy; Hageman, Amber; Nemhauser, Jennifer L

    2016-10-04

    Auxin-regulated transcription pivots on the interaction between the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) repressor proteins and the AUXIN RESPONSE FACTOR (ARF) transcription factors. Recent structural analyses of ARFs and Aux/IAAs have raised questions about the functional complexes driving auxin transcriptional responses. To parse the nature and significance of ARF-DNA and ARF-Aux/IAA interactions, we analyzed structure-guided variants of synthetic auxin response circuits in the budding yeast Saccharomyces cerevisiae Our analysis revealed that promoter architecture could specify ARF activity and that ARF19 required dimerization at two distinct domains for full transcriptional activation. In addition, monomeric Aux/IAAs were able to repress ARF activity in both yeast and plants. This systematic, quantitative structure-function analysis identified a minimal complex-comprising a single Aux/IAA repressing a pair of dimerized ARFs-sufficient for auxin-induced transcription.

  19. Conceptual DFT: the chemical relevance of higher response functions.

    Science.gov (United States)

    Geerlings, P; De Proft, F

    2008-06-07

    In recent years conceptual density functional theory offered a perspective for the interpretation/prediction of experimental/theoretical reactivity data on the basis of a series of response functions to perturbations in the number of electrons and/or external potential. This approach has enabled the sharp definition and computation, from first principles, of a series of well-known but sometimes vaguely defined chemical concepts such as electronegativity and hardness. In this contribution, a short overview of the shortcomings of the simplest, first order response functions is illustrated leading to a description of chemical bonding in a covalent interaction in terms of interacting atoms or groups, governed by electrostatics with the tendency to polarize bonds on the basis of electronegativity differences. The second order approach, well known until now, introduces the hardness/softness and Fukui function concepts related to polarizability and frontier MO theory, respectively. The introduction of polarizability/softness is also considered in a historical perspective in which polarizability was, with some exceptions, mainly put forward in non covalent interactions. A particular series of response functions, arising when the changes in the external potential are solely provoked by changes in nuclear configurations (the "R-analogues") are also systematically considered. The main part of the contribution is devoted to third order response functions which, at first sight, may be expected not to yield chemically significant information, as turns out to be for the hyperhardness. A counterexample is the dual descriptor and its R analogue, the initial hardness response, which turns out to yield a firm basis to regain the Woodward-Hoffmann rules for pericyclic reactions based on a density-only basis, i.e. without involving the phase, sign, symmetry of the wavefunction. Even the second order nonlinear response functions are shown possibly to bear interesting information, e

  20. Test of the consistency of various linearized semiclassical initial value time correlation functions in application to inelastic neutron scattering from liquid para-hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Miller, William; Liu, Jian; Miller, William H.

    2008-03-15

    The linearized approximation to the semiclassical initial value representation (LSC-IVR) is used to calculate time correlation functions relevant to the incoherent dynamic structure factor for inelastic neutron scattering from liquid para-hydrogen at 14 K. Various time correlations functions were used which, if evaluated exactly, would give identical results, but they do not because the LSC-IVR is approximate. Some of the correlation functions involve only linear operators, and others involve non-linear operators. The consistency of the results obtained with the various time correlation functions thus provides a useful test of the accuracy of the LSC-IVR approximation and its ability to treat correlation functions involving both linear and nonlinear operators in realistic anharmonic systems. The good agreement of the results obtained from different correlation functions, their excellent behavior in the spectral moment tests based on the exact moment constraints, and their semi-quantitative agreement with the inelastic neutron scattering experimental data all suggest that the LSC-IVR is indeed a good short-time approximation for quantum mechanical correlation functions.

  1. Global functional analyses of cellular responses to pore-forming toxins.

    Directory of Open Access Journals (Sweden)

    Cheng-Yuan Kao

    2011-03-01

    Full Text Available Here we present the first global functional analysis of cellular responses to pore-forming toxins (PFTs. PFTs are uniquely important bacterial virulence factors, comprising the single largest class of bacterial protein toxins and being important for the pathogenesis in humans of many Gram positive and Gram negative bacteria. Their mode of action is deceptively simple, poking holes in the plasma membrane of cells. The scattered studies to date of PFT-host cell interactions indicate a handful of genes are involved in cellular defenses to PFTs. How many genes are involved in cellular defenses against PFTs and how cellular defenses are coordinated are unknown. To address these questions, we performed the first genome-wide RNA interference (RNAi screen for genes that, when knocked down, result in hypersensitivity to a PFT. This screen identifies 106 genes (∼0.5% of genome in seven functional groups that protect Caenorhabditis elegans from PFT attack. Interactome analyses of these 106 genes suggest that two previously identified mitogen-activated protein kinase (MAPK pathways, one (p38 studied in detail and the other (JNK not, form a core PFT defense network. Additional microarray, real-time PCR, and functional studies reveal that the JNK MAPK pathway, but not the p38 MAPK pathway, is a key central regulator of PFT-induced transcriptional and functional responses. We find C. elegans activator protein 1 (AP-1; c-jun, c-fos is a downstream target of the JNK-mediated PFT protection pathway, protects C. elegans against both small-pore and large-pore PFTs and protects human cells against a large-pore PFT. This in vivo RNAi genomic study of PFT responses proves that cellular commitment to PFT defenses is enormous, demonstrates the JNK MAPK pathway as a key regulator of transcriptionally-induced PFT defenses, and identifies AP-1 as the first cellular component broadly important for defense against large- and small-pore PFTs.

  2. γ strength function and level density of 208Pb from forward-angle proton scattering at 295 MeV

    Science.gov (United States)

    Bassauer, S.; von Neumann-Cosel, P.; Tamii, A.

    2016-11-01

    Background: γ strength functions (GSFs) and level densities (LDs) are essential ingredients of statistical nuclear reaction theory with many applications in astrophysics, reactor design, and waste transmutation. Purpose: The aim of the present work is a test of systematic parametrizations of the GSF recommended by the RIPL-3 database for the case of 208Pb. The upward GSF and LD in 208Pb are compared to γ decay data from an Oslo-type experiment to examine the validity of the Brink-Axel (BA) hypothesis. Methods: The E 1 and M1 parts of the total GSF are determined from high-resolution forward angle inelastic proton scattering data taken at 295 MeV at the Research Center for Nuclear Physics (RCNP), Osaka, Japan. The total LD in 208Pb is derived from the 1- LD extracted with a fluctuation analysis in the energy region of the isovector giant dipole resonance. Results: The E 1 GSF is compared to parametrizations recommended by the RIPL-3 database showing systematic deficiencies of all models in the energy region around neutron threshold. The new data for the poorly known spin-flip M 1 resonance call for a substantial revision of the model suggested in RIPL-3. The total GSF derived from the present data is larger in the PDR energy region than the Oslo data but the strong fluctuations due to the low LD resulting from the double shell closure of 208Pb prevent a conclusion on a possible violation of the BA hypothesis. Using the parameters suggested by RIPL-3 for a description of the LD in 208Pb with the back-shifted Fermi gas model, remarkable agreement between the two experiments spanning a wide excitation energy range is obtained. Conclusions: Systematic parametrizations of the E 1 and M 1 GSF parts need to be reconsidered at low excitation energies. The good agreement of the LD provides an independent confirmation of the approach underlying the decomposition of GSF and LD in Oslo-type experiments.

  3. Analytical evaluation of Fukui functions and real-space linear response function.

    Science.gov (United States)

    Yang, Weitao; Cohen, Aron J; De Proft, Frank; Geerlings, Paul

    2012-04-14

    Many useful concepts developed within density functional theory provide much insight for the understanding and prediction of chemical reactivity, one of the main aims in the field of conceptual density functional theory. While approximate evaluations of such concepts exist, the analytical and efficient evaluation is, however, challenging, because such concepts are usually expressed in terms of functional derivatives with respect to the electron density, or partial derivatives with respect to the number of electrons, complicating the connection to the computational variables of the Kohn-Sham one-electron orbitals. Only recently, the analytical expressions for the chemical potential, one of the key concepts, have been derived by Cohen, Mori-Sánchez, and Yang, based on the potential functional theory formalism. In the present work, we obtain the analytical expressions for the real-space linear response function using the coupled perturbed Kohn-Sham and generalized Kohn-Sham equations, and the Fukui functions using the previous analytical expressions for chemical potentials of Cohen, Mori-Sánchez, and Yang. The analytical expressions are exact within the given exchange-correlation functional. They are applicable to all commonly used approximate functionals, such as local density approximation (LDA), generalized gradient approximation (GGA), and hybrid functionals. The analytical expressions obtained here for Fukui function and linear response functions, along with that for the chemical potential by Cohen, Mori-Sánchez, and Yang, provide the rigorous and efficient evaluation of the key quantities in conceptual density functional theory within the computational framework of the Kohn-Sham and generalized Kohn-Sham approaches. Furthermore, the obtained analytical expressions for Fukui functions, in conjunction with the linearity condition of the ground state energy as a function of the fractional charges, also lead to new local conditions on the exact functionals

  4. Response of Korean pine's functional traits to geography and climate.

    Directory of Open Access Journals (Sweden)

    Yichen Dong

    Full Text Available This study analyzed the characteristics of Korean pine (Pinus koraiensis functional trait responses to geographic and climatic factors in the eastern region of Northeast China (41°-48°N and the linear relationships among Korean pine functional traits, to explore this species' adaptability and ecological regulation strategies under different environmental conditions. Korean pine samples were collected from eight sites located at different latitudes, and the following factors were determined for each site: geographic factors-latitude, longitude, and altitude; temperature factors-mean annual temperature (MAT, growth season mean temperature (GST, and mean temperature of the coldest month (MTCM; and moisture factors-annual precipitation (AP, growth season precipitation (GSP, and potential evapotranspiration (PET. The Korean pine functional traits examined were specific leaf area (SLA, leaf thickness (LT, leaf dry matter content (LDMC, specific root length (SRL, leaf nitrogen content (LNC, leaf phosphorus content (LPC, root nitrogen content (RNC, and root phosphorus content (RPC. The results showed that Korean pine functional traits were significantly correlated to latitude, altitude, GST, MTCM, AP, GSP, and PET. Among the Korean pine functional traits, SLA showed significant linear relationships with LT, LDMC, LNC, LPC, and RPC, and LT showed significant linear relationships with LDMC, SRL, LNC, LPC, RNC, and RPC; the linear relationships between LNC, LPC, RNC, and RPC were also significant. In conclusion, Korean pine functional trait responses to latitude resulted in its adaptation to geographic and climatic factors. The main limiting factors were precipitation and evapotranspiration, followed by altitude, latitude, GST, and MTCM. The impacts of longitude and MAT were not obvious. Changes in precipitation and temperature were most responsible for the close correlation among Korean pine functional traits, reflecting its adaption to habitat

  5. Hydrogen dynamics in Na3AlH6: A combined density functional theory and quasielastic neutron scattering study

    DEFF Research Database (Denmark)

    Zsigmond, G.; Manoshin, S.; Lieutenant, K.

    2007-01-01

    Handling of polarization became very important in simulations of neutron scattering. One of the very comprehensive and open-source neutron simulation package, VITESS, has been intensely involved in polarized neutron simulations. Several examples will be shown here. Another similar package NISP al...

  6. Thomson Scattering

    NARCIS (Netherlands)

    Donne, A. J. H.

    1994-01-01

    Thomson scattering is a very powerful diagnostic which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can be diagnosed. When the wave vector is much larger than the plasma Debye length, the total scattered power is

  7. Numerical integration of detector response functions via Monte Carlo simulations

    Science.gov (United States)

    Kelly, K. J.; O'Donnell, J. M.; Gomez, J. A.; Taddeucci, T. N.; Devlin, M.; Haight, R. C.; White, M. C.; Mosby, S. M.; Neudecker, D.; Buckner, M. Q.; Wu, C. Y.; Lee, H. Y.

    2017-09-01

    Calculations of detector response functions are complicated because they include the intricacies of signal creation from the detector itself as well as a complex interplay between the detector, the particle-emitting target, and the entire experimental environment. As such, these functions are typically only accessible through time-consuming Monte Carlo simulations. Furthermore, the output of thousands of Monte Carlo simulations can be necessary in order to extract a physics result from a single experiment. Here we describe a method to obtain a full description of the detector response function using Monte Carlo simulations. We also show that a response function calculated in this way can be used to create Monte Carlo simulation output spectra a factor of ∼ 1000 × faster than running a new Monte Carlo simulation. A detailed discussion of the proper treatment of uncertainties when using this and other similar methods is provided as well. This method is demonstrated and tested using simulated data from the Chi-Nu experiment, which measures prompt fission neutron spectra at the Los Alamos Neutron Science Center.

  8. Retrieving impulse response function amplitudes from the ambient seismic field

    Science.gov (United States)

    Viens, Loïc; Denolle, Marine; Miyake, Hiroe; Sakai, Shin'ichi; Nakagawa, Shigeki

    2017-07-01

    Seismic interferometry is now widely used to retrieve the impulse response function of the Earth between two distant seismometers. The phase information has been the focus of most passive imaging studies, as conventional seismic tomography uses traveltime measurements. The amplitude information, however, is harder to interpret because it strongly depends on the distribution of ambient seismic field sources and on the multitude of processing methods. Our study focuses on the latter by comparing the amplitudes of the impulse response functions calculated between seismic stations in the Kanto sedimentary basin, Japan, using several processing techniques. This region provides a unique natural laboratory to test the reliability of the amplitudes with complex wave propagation through the basin, and dense observations from the Metropolitan Seismic Observation network. We compute the impulse response functions using the cross correlation, coherency and deconvolution techniques of the raw ambient seismic field and the cross correlation of 1-bit normalized data. To validate the amplitudes of the impulse response functions, we use a shallow Mw 5.8 earthquake that occurred on the eastern edge of Kanto Basin and close to a station that is used as the virtual source. Both S and surface waves are retrieved in the causal part of the impulse response functions computed with all the different techniques. However, the amplitudes obtained from the deconvolution method agree better with those of the earthquake. Despite the expected wave attenuation due to the soft sediments of the Kanto Basin, seismic amplification caused by the basin geometry dominates the amplitudes of S and surface waves and is captured by the ambient seismic field. To test whether or not the anticausal part of the impulse response functions from deconvolution also contains reliable amplitude information, we use another virtual source located on the western edge of the basin. We show that the surface wave amplitudes

  9. Paired Pulse Basis Functions for the Method of Moments EFIE Solution of Electromagnetic Problems Involving Arbitrarily-shaped, Three-dimensional Dielectric Scatterers

    Science.gov (United States)

    MacKenzie, Anne I.; Rao, Sadasiva M.; Baginski, Michael E.

    2007-01-01

    A pair of basis functions is presented for the surface integral, method of moment solution of scattering by arbitrarily-shaped, three-dimensional dielectric bodies. Equivalent surface currents are represented by orthogonal unit pulse vectors in conjunction with triangular patch modeling. The electric field integral equation is employed with closed geometries for dielectric bodies; the method may also be applied to conductors. Radar cross section results are shown for dielectric bodies having canonical spherical, cylindrical, and cubic shapes. Pulse basis function results are compared to results by other methods.

  10. Reinterpreting space, time lags, and functional responses in ecological models.

    Science.gov (United States)

    Keeling, M J; Wilson, H B; Pacala, S W

    2000-12-01

    Natural enemy-victim interactions are of major applied importance and of fundamental interest to ecologists. A key question is what stabilizes these interactions, allowing the long-term coexistence of the two species. Three main theoretical explanations have been proposed: behavioral responses, time-dependent factors such as delayed density dependence, and spatial heterogeneity. Here, using the powerful moment-closure technique, we show a fundamental equivalence between these three elements. Limited movement by organisms is a ubiquitous feature of ecological systems, allowing spatial structure to develop; we show that the effects of this can be naturally described in terms of time lags or within-generation functional responses.

  11. Executing application function calls in response to an interrupt

    Science.gov (United States)

    Almasi, Gheorghe; Archer, Charles J.; Giampapa, Mark E.; Gooding, Thomas M.; Heidelberger, Philip; Parker, Jeffrey J.

    2010-05-11

    Executing application function calls in response to an interrupt including creating a thread; receiving an interrupt having an interrupt type; determining whether a value of a semaphore represents that interrupts are disabled; if the value of the semaphore represents that interrupts are not disabled: calling, by the thread, one or more preconfigured functions in dependence upon the interrupt type of the interrupt; yielding the thread; and if the value of the semaphore represents that interrupts are disabled: setting the value of the semaphore to represent to a kernel that interrupts are hard-disabled; and hard-disabling interrupts at the kernel.

  12. About temporary autocorrelation function of fluctuations of the scattered radiation of the focused laser beam (0.63 mm) in the surface atmosphere in rain, drizzle and fog

    Science.gov (United States)

    Vostretsov, N. A.; Zhukov, A. F.

    2015-11-01

    Measured temporal autocorrelation function the fluctuations of the scattered radiation of the focused laser beam (0.63 μm) in the surface atmosphere in rain, drizzle and fog on the highway with a length of 130 m. Found that the time correlation of the fluctuations of the scattered radiation of the focused laser beam in the rain and drizzle decreases with increasing perpendicular component to the path the wind speed is at close to atmospheric conditions (with close values of optical depth and particle size of atmospheric precipitation). The time correlation in the fog more, than the time correlation in the drizzle. It is an order of magnitude or more greater than in the rain.

  13. Pointwise influence matrices for functional-response regression.

    Science.gov (United States)

    Reiss, Philip T; Huang, Lei; Wu, Pei-Shien; Chen, Huaihou; Colcombe, Stan

    2017-12-01

    We extend the notion of an influence or hat matrix to regression with functional responses and scalar predictors. For responses depending linearly on a set of predictors, our definition is shown to reduce to the conventional influence matrix for linear models. The pointwise degrees of freedom, the trace of the pointwise influence matrix, are shown to have an adaptivity property that motivates a two-step bivariate smoother for modeling nonlinear dependence on a single predictor. This procedure adapts to varying complexity of the nonlinear model at different locations along the function, and thereby achieves better performance than competing tensor product smoothers in an analysis of the development of white matter microstructure in the brain. © 2017, The International Biometric Society.

  14. The effect of temporal impulse response on experimental reduction of photon scatter in time-resolved diffuse optical tomography

    Science.gov (United States)

    Valim, Niksa; Brock, James; Leeser, Miriam; Niedre, Mark

    2013-01-01

    New fast detector technology has driven significant renewed interest in time-resolved measurement of early photons in improving imaging resolution in diffuse optical tomography and fluorescence mediated tomography in recent years. In practice, selection of early photons results in significantly narrower instrument photon density sensitivity functions (PDSFs) than the continuous wave case, resulting in a better conditioned reconstruction problem. In this work, we studied the quantitative impact of the instrument temporal impulse response function (TIRF) on experimental PDSFs in tissue mimicking optical phantoms. We used a multimode fiber dispersion method to vary the system TIRF over a range of representative literature values. Substantial disagreement in PDSF width--by up to 40%--was observed between experimental measurements and Monte Carlo (MC) models of photon propagation over the range of TIRFs studied. On average, PDSFs were broadened by about 0.3 mm at the center plane of the 2 cm wide imaging chamber per 100 ps of the instrument TIRF at early times. Further, this broadening was comparable on both the source and detector sides. Results were confirmed by convolution of instrument TIRFs with MC simulations. These data also underscore the importance of correcting imaging PDSFs for the instrument TIRF when performing tomographic image reconstruction to ensure accurate data-model agreement.

  15. Cortisol stress responses and children's behavioral functioning at school.

    Science.gov (United States)

    Simons, Sterre S H; Cillessen, Antonius H N; de Weerth, Carolina

    2017-03-01

    The present study investigated whether cortisol stress responses of 6-year-olds were associated with their behavioral functioning at school. Additionally, the moderating role of stress in the family environment was examined. To this end, 149 healthy children (Mage  = 6.09 years; 70 girls) participated in an age-appropriate innovative social evaluative stress test. Saliva cortisol samples were collected six times during the stress test to calculate two indices of the cortisol stress response: cortisol stress reactivity and total stress cortisol. Teachers assessed children's internalizing, externalizing, and prosocial behaviors. Stress in the family environment was operationalized as maternally reported parenting stress. Results indicated a significant increase in cortisol concentrations in response to the stressor. No significant associations were found between cortisol stress responses and behavioral functioning at school and there was no evidence for moderation by maternal parenting stress. Potential theoretical and methodological explanations for these results are discussed. © 2016 The Authors. Developmental Psychobiology Published by Wiley Periodicals, Inc.

  16. Empirical forward scattering phase functions from 0.08 to 16 deg. for randomly shaped terrigenous 1-21 microm sediment grains.

    Science.gov (United States)

    Agrawal, Y C; Mikkelsen, Ole A

    2009-05-25

    We present in-water forward scattering phase functions covering the angle range 0.08 to 16 degrees for 19 narrow-sized dispersions of randomly shaped sediment grains. These dispersions cover particle size range from 1 to 20 microns. These phase functions offer a realistic alternative to Mie theory. Qualitatively, (i) the magnitude of phase functions at the smallest angles for equal size spheres and randomly shaped particles are nearly equal; (ii) the oscillations predicted by Mie theory for spheres disappear for random shaped grains, and (iii) the tendency of phase functions of large spheres to merge at large angles is also seen with randomly shaped grains. The data are also provided in tabulated form.

  17. Critical scattering

    Energy Technology Data Exchange (ETDEWEB)

    Stirling, W.G. [Liverpool Univ., Dep. of Physics, Liverpool (United Kingdom); Perry, S.C. [Keele Univ. (United Kingdom). Dept. of Physics

    1996-12-31

    We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO{sub 3} is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs.

  18. Investigation of the Interaction between Nafion Ionomer and Surface Functionalized Carbon Black Using Both Ultrasmall Angle X-ray Scattering and Cryo-TEM

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fan; Xin, Le; Uzunoglu, Aytekin; Qiu, Yang; Stanciu, Lia; Ilavsky, Jan; Li, Wenzhen; Xie, Jian

    2017-02-08

    In making a catalyst ink, the interaction between Nafion ionomer and catalyst support are the key factors that directly affect both ionic conductivity and electronic conductivity of the catalyst layer in a membrane electrode assembly (MEA). One of the major aims of this investigation is to understand the behavior of the catalyst support, Vulcan XC-72 (XC-72) aggregates, in the existence of the Nafion ionomer in a catalyst ink to fill the knowledge gap of the interaction of these components. The dispersion of catalyst ink not only depends on the solvent, but also depends on the interaction of Nafion and carbon particles in the ink. The interaction of Nafion ionomer particles and XC-72 catalyst aggregates in liquid media was studied using ultra small angle x-ray scattering (USAXS) and cryogenic TEM techniques. Carbon black XC-72) and functionalized carbon black systems were introduced to study the interaction behaviors. A multiple curve fitting was used to extract the particle size and size distribution from scattering data. The results suggest that the particle size and size distribution of each system changed significantly in Nafion + XC-72 system, Nafion + NH2-XC72 system, and Nafion + SO3H-XC-72 system, which indicates that an interaction among these components (i.e. ionomer particles and XC-72 aggregates) exists. The cryogenic TEM, which allows for the observation the size of particles in a liquid, was used to validate the scattering results and shows excellent agreement.

  19. Introducing a standard method for experimental determination of the solvent response in laser pump, x-ray probe time-resolved wide-angle x-ray scattering experiments on systems in solution

    DEFF Research Database (Denmark)

    Kjær, Kasper Skov; Brandt van Driel, Tim; Kehres, Jan

    2013-01-01

    In time-resolved laser pump, X-ray probe wide-angle X-ray scattering experiments on systems in solution the structural response of the system is accompanied by a solvent response. The solvent response is caused by reorganization of the bulk solvent following the laser pump event, and in order to ...

  20. pH-Responsive Structural Change of PEGylated Amine-Bearing Nanogel Explored by Small Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Goshu; Shinohara, Yuya; Amemiya, Yoshiyuki [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Akiba, Isamu; Sakurai, Kazuo [Department of Chemistry and Biochemistry, University of Kitakyushu (Japan); Tamura, Atsushi; Oishi, Motoi; Nagasaki, Yukio, E-mail: goshu@x-ray.k.u-tokyo.ac.jp [Department of Materials Science, Graduated School of Pure and Applied Science, University of Tsukuba (Japan)

    2011-01-01

    A PEGylated nanogel sphere containing cross-linked amino groups in its core undergoes dramatic volumetric changes upon pH-change. We measured small angle x-ray scattering from the nanogel and analyzed the data with a core-shell sphere model to determine the core size upon pH-change from 8.0 to 5.8. The protonation of the poly-amine core due to the pH-change increased the core volume by over 300%. Combining the obtained core volume and the absolute intensity, we estimated the change of the core electron density.

  1. Immune function trade-offs in response to parasite threats.

    Science.gov (United States)

    Kirschman, Lucas J; Quade, Adam H; Zera, Anthony J; Warne, Robin W

    2017-04-01

    Immune function is often involved in physiological trade-offs because of the energetic costs of maintaining constitutive immunity and mounting responses to infection. However, immune function is a collection of discrete immunity factors and animals should allocate towards factors that combat the parasite threat with the highest fitness cost. For example, animals on dispersal fronts of expanding population may be released from density-dependent diseases. The costs of immunity, however, and life history trade-offs in general, are often context dependent. Trade-offs are often most apparent under conditions of unusually limited resources or when animals are particularly stressed, because the stress response can shift priorities. In this study we tested how humoral and cellular immune factors vary between phenotypes of a wing dimorphic cricket and how physiological stress influences these immune factors. We measured constitutive lysozyme activity, a humoral immune factor, and encapsulation response, a cellular immune factor. We also stressed the crickets with a sham predator in a full factorial design. We found that immune strategy could be explained by the selective pressures encountered by each morph and that stress decreased encapsulation, but not lysozyme activity. These results suggest a possible trade-off between humoral and cellular immunity. Given limited resources and the expense of immune factors, parasite pressures could play a key factor in maintaining insect polyphenism via disruptive selection. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. How linear features alter predator movement and the functional response.

    KAUST Repository

    McKenzie, Hannah W

    2012-01-18

    In areas of oil and gas exploration, seismic lines have been reported to alter the movement patterns of wolves (Canis lupus). We developed a mechanistic first passage time model, based on an anisotropic elliptic partial differential equation, and used this to explore how wolf movement responses to seismic lines influence the encounter rate of the wolves with their prey. The model was parametrized using 5 min GPS location data. These data showed that wolves travelled faster on seismic lines and had a higher probability of staying on a seismic line once they were on it. We simulated wolf movement on a range of seismic line densities and drew implications for the rate of predator-prey interactions as described by the functional response. The functional response exhibited a more than linear increase with respect to prey density (type III) as well as interactions with seismic line density. Encounter rates were significantly higher in landscapes with high seismic line density and were most pronounced at low prey densities. This suggests that prey at low population densities are at higher risk in environments with a high seismic line density unless they learn to avoid them.

  3. How linear features alter predator movement and the functional response.

    Science.gov (United States)

    McKenzie, Hannah W; Merrill, Evelyn H; Spiteri, Raymond J; Lewis, Mark A

    2012-04-06

    In areas of oil and gas exploration, seismic lines have been reported to alter the movement patterns of wolves (Canis lupus). We developed a mechanistic first passage time model, based on an anisotropic elliptic partial differential equation, and used this to explore how wolf movement responses to seismic lines influence the encounter rate of the wolves with their prey. The model was parametrized using 5 min GPS location data. These data showed that wolves travelled faster on seismic lines and had a higher probability of staying on a seismic line once they were on it. We simulated wolf movement on a range of seismic line densities and drew implications for the rate of predator-prey interactions as described by the functional response. The functional response exhibited a more than linear increase with respect to prey density (type III) as well as interactions with seismic line density. Encounter rates were significantly higher in landscapes with high seismic line density and were most pronounced at low prey densities. This suggests that prey at low population densities are at higher risk in environments with a high seismic line density unless they learn to avoid them.

  4. Transverse isospin response function of asymmetric nuclear matter from a local isospin density functional

    Science.gov (United States)

    Lipparini, Enrico; Pederiva, Francesco

    2016-08-01

    The time dependent local isospin density approximation (TDLIDA) has been extended to the study of the transverse isospin response function in nuclear matter with an arbitrary neutron-proton asymmetry parameter ξ . The energy density functional has been chosen in order to fit existing accurate quantum Monte Carlo calculations with a density dependent potential. The evolution of the response with ξ in the Δ Tz=±1 channels is quite different. While the strength of the Δ Tz=+1 channel disappears rather quickly by increasing the asymmetry, the Δ Tz=-1 channel develops a stronger and stronger collective mode that in the regime typical of neutron star matter at β equilibrium almost completely exhausts the excitation spectrum of the system. The neutrino mean free paths obtained from the TDLIDA responses are strongly dependent on ξ and on the presence of collective modes, leading to a sizable difference with respect to the prediction of the Fermi gas model.

  5. Probing Amorphous Components in High Temperature TE Materials by in situ Total Scattering and the Pair Distribution Function (PDF) Method

    DEFF Research Database (Denmark)

    Reardon, Hazel; Iversen, Bo Brummerstedt; Blichfeld, Anders Bank

    to heating cycles, then we are closer to distinguishing how we may generate materials that do not undergo specific structure reorientation processes, and/or how we may mitigate them before they occur. Here, we will present a total scattering and PDF study that probes the local structure of the Type......-I clathrate Ba8Ga16Ge30. This suggests that local structure reorientations in the cage are likely to be the root cause of the degradation of the structure. This deepens our understanding of disordered clathrates, and provides evidence that the PDF technique is an effective method for probing local structure...

  6. Measurements of the fast-ion distribution function at ASDEX upgrade by collective Thomson scattering (CTS) using active and passive views

    DEFF Research Database (Denmark)

    Nielsen, Stefan Kragh; Stejner Pedersen, Morten; Rasmussen, Jesper

    2015-01-01

    Collective Thomson scattering (CTS) can provide measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. On ASDEX Upgrade, the measured spectra include an additional signal which previously has hampered data interpretation. A new set-up using two......, the measured spectra agree quantitatively with the synthetic spectra in periods with and without NBI heating. For the discharges investigated, the central velocity distribution of neutral beam ions can be described by classical slowing down. These results will have a major impact on ITER physics exploration...

  7. Iterative algorithm based on a combination of vector similarity measure and B-spline functions for particle analysis in forward scattering

    Science.gov (United States)

    Wang, Tian'en; Shen, Jianqi; Lin, Chengjun

    2017-06-01

    The vector similarity measure (VSM) was recently introduced into the inverse problem for particle analysis based on forward light scattering and its modified version was proposed to adapt for multi-modal particle systems. It is found that the algorithm is stable and efficient but the extracted solutions are usually oscillatory, especially for widely distributed particle systems. In order to improve this situation, an iterative VSM method combined with cubic B-spline functions (B-VSM) is presented. Simulations and experiments show that, compared with the old versions, this modification is more robust and efficient.

  8. Preservation of the morphology of a self-encapsulated thin titania film in a functional multilayer stack: an X-ray scattering study.

    Science.gov (United States)

    Perlich, Jan; Memesa, Mine; Diethert, Alexander; Metwalli, Ezzeldin; Wang, Weinan; Roth, Stephan V; Timmann, Andreas; Gutmann, Jochen S; Müller-Buschbaum, Peter

    2009-03-23

    Tailoring of the titania morphology is achieved by the combination of a triblock copolymer, acting as structure-directing agent, and a sol-gel chemistry enabling the incorporation of the provided inorganic material (titania) into the selected phase of the triblock copolymer. Spin-coating of the solution on FTO-coated glass, followed by plasma etching and calcination of the thin film results in the formation of self-encapsulated crystalline titania nanostructures. The fabricated nanostructures are coated stepwise with dye, conductive polymers and gold forming a functional multilayer stack. An advanced small-angle scattering technique probing the sample with X-ray synchrotron radiation under grazing incidence (GISAXS) is employed for the characterization of the preparation route, as scattering allows accessing the structure inside the multilayers. The tailored titania morphology is preserved during the preparation route towards the functional multilayer stack of a photovoltaic demonstration cell. Two clearly distinguishable structures originate from the substrate and the titania templated by the triblock copolymer; hence the other layers induce no additional structures. Therefore, this investigation provides the evidence that the effort spent to tailor the morphology is justified by the preservation of the self-encapsulated titania morphology that is created by the structure-directing agent throughout the functional multilayer stack build-up.

  9. Scattering of light and other electromagnetic radiation

    CERN Document Server

    Kerker, Milton

    1969-01-01

    The Scattering of Light and Other Electromagnetic Radiation discusses the theory of electromagnetic scattering and describes some practical applications. The book reviews electromagnetic waves, optics, the interrelationships of main physical quantities and the physical concepts of optics, including Maxwell's equations, polarization, geometrical optics, interference, and diffraction. The text explains the Rayleigh2 theory of scattering by small dielectric spheres, the Bessel functions, and the Legendre functions. The author also explains how the scattering functions for a homogenous sphere chan

  10. TUTOR’S FUNCTIONAL RESPONSIBILITIES OF PUPILS DISTANCE LEARNING

    Directory of Open Access Journals (Sweden)

    Tamara O. Derba

    2011-02-01

    Full Text Available In the article it is considered an urgency in scientific terminology of the term "tutor" according to occurrence of a new profession in education system of Ukraine that is caused by a modern level of information society development. Existing examples of educational institutions which today prepare tutors are considered. Necessity of modeling of network interaction, the organization of educational "distance" conferences during preparation of tutors is conditioned. In the article functional responsibilities of the tutor are defined. Specificity of distance learning which forms the especial requirements to the tutor different from the requirements to the usual teacher is analysed.

  11. Bethe Ansatz, Inverse Scattering Transform and Tropical Riemann Theta Function in a Periodic Soliton Cellular Automaton for A_n^{(1}

    Directory of Open Access Journals (Sweden)

    Atsuo Kuniba

    2010-01-01

    Full Text Available We study an integrable vertex model with a periodic boundary condition associated with U_q(A_n^{(1} at the crystallizing point q=0. It is an (n+1-state cellular automaton describing the factorized scattering of solitons. The dynamics originates in the commuting family of fusion transfer matrices and generalizes the ultradiscrete Toda/KP flow corresponding to the periodic box-ball system. Combining Bethe ansatz and crystal theory in quantum group, we develop an inverse scattering/spectral formalism and solve the initial value problem based on several conjectures. The action-angle variables are constructed representing the amplitudes and phases of solitons. By the direct and inverse scattering maps, separation of variables into solitons is achieved and nonlinear dynamics is transformed into a straight motion on a tropical analogue of the Jacobi variety. We decompose the level set into connected components under the commuting family of time evolutions and identify each of them with the set of integer points on a torus. The weight multiplicity formula derived from the q=0 Bethe equation acquires an elegant interpretation as the volume of the phase space expressed by the size and multiplicity of these tori. The dynamical period is determined as an explicit arithmetical function of the n-tuple of Young diagrams specifying the level set. The inverse map, i.e., tropical Jacobi inversion is expressed in terms of a tropical Riemann theta function associated with the Bethe ansatz data. As an application, time average of some local variable is calculated.

  12. Computation of Green's Function of 3-D Radiative Transport Equations for Non-isotropic Scattering of P and Unpolarized S Waves

    Science.gov (United States)

    Margerin, Ludovic

    2017-11-01

    In this work, I propose to model the propagation of high-frequency seismic waves in the heterogeneous Earth by means of a coupled system of radiative transfer equations for P and S waves. The model describes the propagation of both coherent and diffuse waves in a statistically isotropic heterogeneous medium and takes into account key phenomena such as scattering conversions between propagation modes, scattering anisotropy and absorption. The main limitation of the approach lies in the neglect of the shear wave polarization information. The canonical case of a medium with uniform scattering and absorption properties is studied in details. Using an adjoint formalism, Green's functions (isotropic point source solutions) of the transport equation are shown to obey a reciprocity relation relating the P energy density radiated by an S source to the S energy density radiated by a P source. A spectral method of calculation of the Green's function is presented. Application of Fourier, Hankel and Legendre transforms to time, space and angular variables, respectively, turns the equation of transport into a numerically tractable penta-diagonal linear system of equations. The implementation of the spectral method is discussed in details and validated through one-to-one comparisons with Monte Carlo simulations. Numerical experiments in different propagation regimes illustrate that the ratio between the correlation length of heterogeneities and the incident wavelength plays a key role in the rate of stabilization of the P-to- S energy ratio in the coda. The results suggest that the rapid stabilization of energy ratios observed in the seismic coda is a signature of the broadband nature of crustal heterogeneities. The impact of the texture of the medium on both pulse broadening and generation of converted S wave arrivals by explosion sources is illustrated. The numerical study indicates that smooth media enhance the visibility of ballistic-like S arrivals from P sources.

  13. Computation of Green's Function of 3-D Radiative Transport Equations for Non-isotropic Scattering of P and Unpolarized S Waves

    Science.gov (United States)

    Margerin, Ludovic

    2017-07-01

    In this work, I propose to model the propagation of high-frequency seismic waves in the heterogeneous Earth by means of a coupled system of radiative transfer equations for P and S waves. The model describes the propagation of both coherent and diffuse waves in a statistically isotropic heterogeneous medium and takes into account key phenomena such as scattering conversions between propagation modes, scattering anisotropy and absorption. The main limitation of the approach lies in the neglect of the shear wave polarization information. The canonical case of a medium with uniform scattering and absorption properties is studied in details. Using an adjoint formalism, Green's functions (isotropic point source solutions) of the transport equation are shown to obey a reciprocity relation relating the P energy density radiated by an S source to the S energy density radiated by a P source. A spectral method of calculation of the Green's function is presented. Application of Fourier, Hankel and Legendre transforms to time, space and angular variables, respectively, turns the equation of transport into a numerically tractable penta-diagonal linear system of equations. The implementation of the spectral method is discussed in details and validated through one-to-one comparisons with Monte Carlo simulations. Numerical experiments in different propagation regimes illustrate that the ratio between the correlation length of heterogeneities and the incident wavelength plays a key role in the rate of stabilization of the P-to-S energy ratio in the coda. The results suggest that the rapid stabilization of energy ratios observed in the seismic coda is a signature of the broadband nature of crustal heterogeneities. The impact of the texture of the medium on both pulse broadening and generation of converted S wave arrivals by explosion sources is illustrated. The numerical study indicates that smooth media enhance the visibility of ballistic-like S arrivals from P sources.

  14. Visual functions in amblyopia as determinants of response to treatment.

    Science.gov (United States)

    Singh, Vinita; Agrawal, Siddharth

    2013-01-01

    To describe the visual functions in amblyopia as determinants of response to treatment. Sixty-nine patients with unilateral and bilateral amblyopia (114 amblyopic eyes) 3 to 15 years old (mean age: 8.80 ± 2.9 years), 40 males (58%) and 29 females (42%), were included in this study. All patients were treated by conventional occlusion 6 hours per day for mild to moderate amblyopia (visual acuity 0.70 or better) and full-time for 4 weeks followed by 6 hours per day for severe amblyopia (visual acuity 0.8 or worse). During occlusion, near activities requiring hand-eye coordination were advised. The follow-up examination was done at 3 and 6 months. Improvement in visual acuity was evaluated on the logMAR chart and correlated with the visual functions. Statistical analysis was done using Wilcoxon rank sum test (Mann-Whitney U test) and Kruskal-Wallis analysis. There was a statistically significant association of poor contrast sensitivity with the grade of amblyopia (P amblyopia (P amblyopia therapy. The grade of amblyopia (initial visual acuity) and accommodation are strong determinants of response to amblyopia therapy, whereas stereopsis and mesopic visual acuity have some value as determinants. Copyright 2013, SLACK Incorporated.

  15. Excitation functions of the analyzing power in elastic proton-proton scattering from 0.45 to 2.5 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Altmeier, M.; Bisplinghoff, J.; Busch, M.; Engelhardt, H.P.; Eversheim, D.; Glende, M.; Hinterberger, F. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Bauer, F.; Buesser, K.; Colberg, T.; Demiroers, L.; Eyser, K.O.; Greiff, J.; Jonas, E.; Krause, H.; Lindemann, T.; Lindlein, J. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Felden, O.; Gebel, R.; Lorentz, B. [Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany); Maier, R.; Maschuw, R.; Meinerzhagen, A.; Prasuhn, D.; Rohdjess, H.; Rosendaal, D.; Von Rossen, P.; Schirm, N.; Schwarz, V.; Scobel, W.; Trelle, H.J.; Ulbrich, K.; Weise, E.; Wellinghausen, A.; Ziegler, R.

    2005-02-01

    Excitation functions A{sub N}(p{sub lab},{theta}{sub c.m.}) of the analyzing power in elastic proton-proton scattering have been measured in an internal target experiment at the Cooler Synchrotron COSY with an unpolarized proton beam and a polarized atomic hydrogen target. Data were taken continuously during the acceleration and deceleration for proton kinetic energies T{sub lab} (momenta p{sub lab}) between 0.45 and 2.5 GeV (1.0 and 3.3 GeV/c) and scattering angles 30 {<=}{theta}{sub c.m.}{<=}90 . The results provide excitation functions and angular distributions of high precision and internal consistency. The data can be used as calibration standard between 0.45 and 2.5 GeV. They have significant impact on phase shift solutions, in particular on the spin triplet phase shifts between 1.0 and 1.8 GeV. (orig.)

  16. Magnetization dissipation in ferromagnets from scattering theory

    Science.gov (United States)

    Brataas, Arne; Tserkovnyak, Yaroslav; Bauer, Gerrit E. W.

    2011-08-01

    The magnetization dynamics of ferromagnets is often formulated in terms of the Landau-Lifshitz-Gilbert (LLG) equation. The reactive part of this equation describes the response of the magnetization in terms of effective fields, whereas the dissipative part is parametrized by the Gilbert damping tensor. We formulate a scattering theory for the magnetization dynamics and map this description on the linearized LLG equation by attaching electric contacts to the ferromagnet. The reactive part can then be expressed in terms of the static scattering matrix. The dissipative contribution to the low-frequency magnetization dynamics can be described as an adiabatic energy pumping process to the electronic subsystem by the time-dependent magnetization. The Gilbert damping tensor depends on the time derivative of the scattering matrix as a function of the magnetization direction. By the fluctuation-dissipation theorem, the fluctuations of the effective fields can also be formulated in terms of the quasistatic scattering matrix. The theory is formulated for general magnetization textures and worked out for monodomain precessions and domain-wall motions. We prove that the Gilbert damping from scattering theory is identical to the result obtained by the Kubo formalism.

  17. Nuclear structure functions in the large-x large-Q2 kinematic region in neutrino deep inelastic scattering

    Science.gov (United States)

    Vakili, M.; Arroyo, C. G.; Auchincloss, P.; de Barbaro, L.; de Barbaro, P.; Bazarko, A. O.; Bernstein, R. H.; Bodek, A.; Bolton, T.; Budd, H.; Conrad, J.; Harris, D. A.; Johnson, R. A.; Kim, J. H.; King, B. J.; Kinnel, T.; Koizumi, G.; Koutsoliotas, S.; Lamm, M. J.; Lefmann, W. C.; Marsh, W.; McFarland, K. S.; McNulty, C.; Mishra, S. R.; Naples, D.; Nienaber, P.; Oreglia, M. J.; Perera, L.; Quintas, P. Z.; Romosan, A.; Sakumoto, W. K.; Schumm, B. A.; Sciulli, F. J.; Seligman, W. G.; Shaevitz, M. H.; Smith, W. H.; Spentzouris, P.; Steiner, R.; Stern, E. G.; Yang, U. K.; Yu, J.

    2000-03-01

    Data from the CCFR E770 neutrino deep inelastic scattering experiment at Fermilab contain events with a large Bjorken x (x>0.7) and high momentum transfer [Q2>50 (GeV/c)2]. A comparison of the data with a model based on no nuclear effects at large x shows a significant excess of events in the data. The addition of Fermi gas motion of the nucleons in the nucleus to the model does not explain the excess. Adding a higher momentum tail due to the formation of ``quasi-deuterons'' makes some improvement. An exponentially falling F2~e-s(x-x0) at large x, predicted by ``multi-quark clusters'' and ``few-nucleon correlations,'' can describe the data. A value of s=8.3+/-0.7(stat)+/-0.7(syst) yields the best agreement with the data.

  18. Response functions of multi-pixel-type CdTe detector: toward development of precise material identification on diagnostic x-ray images by means of photon counting

    Science.gov (United States)

    Hayashi, Hiroaki; Asahara, Takashi; Kimoto, Natsumi; Kanazawa, Yuki; Yamakawa, Tsutomu; Yamamoto, Shuichiro; Yamasaki, Masashi; Okada, Masahiro

    2017-03-01

    Currently, an X-ray imaging system which can produced information used to identify various materials has been developed based on photon counting. It is important to estimate the response function of the detector in order to accomplish highly accurate material identification. Our aim is to simulate the response function of a CdTe detector using Monte-Carlo simulation; at this time, the transportation of incident and scattered photons and secondary produced electrons were precisely simulated without taking into consideration the charge spread in the collecting process of the produced charges (charge sharing effect). First, we set pixel sizes of 50-500μm, the minimum irradiation fields which produce equilibrium conditions were determined. Then, observed peaks in the response function were analyzed with consideration paid to the interactions between incident X-rays and the detector components, Cd and Te. The secondary produced characteristic X-rays play an important role. Accordingly ratios of full energy peak (FEP), scattering X-rays and penetrating X-rays in the calculated response functions were analyzed. When the pixel size of 200μm was used the scattered X-rays were saturated at equilibrium with relatively small fields and efficiency of FEP was kept at a high value (<50%). Finally, we demonstrated the X-ray spectrum which is folded by the response function. Even if the charge sharing effect is not completely corrected when using the electric circuit, there is a possibility that disturbed portions in the measured X-ray spectra can be corrected by using proper calibration, in which the above considerations are taken into account.

  19. Density functional theory study on Herzberg-Teller contribution in Raman scattering from 4-aminothiophenol-metal complex and metal-4-aminothiophenol-metal junction

    Science.gov (United States)

    Liu, Shasha; Zhao, Xiuming; Li, Yuanzuo; Zhao, Xiaohong; Chen, Maodu

    2009-06-01

    Density functional theory (DFT) and time-dependent DFT calculations have been performed to investigate the Raman scattering spectra of metal-molecule complex and metal-molecule-metal junction architectures interconnected with 4-aminothiophenol (PATP) molecule. The simulated profiles of normal Raman scattering (NRS) spectra for the two complexes (Ag2-PATP and PATP-Au2) and the two junctions (Ag2-PATP-Au2 and Au2-PATP-Ag2) are similar to each other, but exhibit obviously different Raman intensities. Due to the lager static polarizabilities of the two junctions, which directly influence the ground state chemical enhancement in NRS spectra, the calculated normal Raman intensities of them are stronger than those of two complexes by the factor of 102. We calculate preresonance Raman scattering (RRS) spectra with incident light at 1064 nm, which is much lower than the S1 electronic transition energy of complexes and junctions. Ag2-PATP-Au2 and Au2-PATP-Ag2 junctions yield higher Raman intensities than those of Ag2-PATP and PATP-Au2 complexes, especially for b2 modes. This effect is mainly attributed to charge transfer (CT) between the metal gap and the PAPT molecule which results in the occurrence of CT resonance enhancement. The calculated pre-RRS spectra strongly depend on the electronic transition state produced by new structures. With excitation at 514.5 nm, the calculated pre-RRS spectra of two complexes and two junctions are stronger than those of with excitation at 1064 nm. A charge difference densities methodology has been used to visually describe chemical enhancement mechanism of RRS spectrum. This methodology aims at visualizing intermolecular CT which provides direct evidence of the Herzberg-Teller mechanism.

  20. Nonlinear response theory for Markov processes. II. Fifth-order response functions

    Science.gov (United States)

    Diezemann, Gregor

    2017-08-01

    The nonlinear response of stochastic models obeying a master equation is calculated up to fifth order in the external field, thus extending the third-order results obtained earlier [G. Diezemann, Phys. Rev. E 85, 051502 (2012), 10.1103/PhysRevE.85.051502]. For sinusoidal fields the 5 ω component of the susceptibility is computed for the model of dipole reorientations in an asymmetric double well potential and for a trap model with a Gaussian density of states. For most realizations of the models a hump is found in the higher-order susceptibilities. In particular, for the asymmetric double well potential model there are two characteristic temperature regimes showing the occurrence of such a hump as compared to a single characteristic regime in the case of the third-order response. In the case of the trap model the results strongly depend on the variable coupled to the field. As for the third-order response, the low-frequency limit of the susceptibility plays a crucial role with respect to the occurrence of a hump. The findings are discussed in light of recent experimental results obtained for supercooled liquids. The differences found for the third-order and the fifth-order response indicate that nonlinear response functions might serve as a powerful tool to discriminate among the large number of existing models for glassy relaxation.

  1. Charge response function and a novel plasmon mode in graphene

    Science.gov (United States)

    Mishchenko, Eugene; Farid, Abdel-Khalek; Gangadharaiah, Suhas

    2008-03-01

    Polarizability of non-interacting 2D Dirac electrons has a inverse square root singularity at the boundary of electron-hole excitations. The screening of this singularity by long-range electron-electron interactions is usually treated within the random phase approximation. The latter is exact only in the limit of N->infinity, where N is the ``color'' degeneracy. We find that the ladder-type vertex corrections become crucial close to the threshold. The strong singularity in the ladder series arises due to the long range interaction between electrons which move almost collinearly to the external momentum. The series is summed up analytically yielding a non- perturbative result: the density and spin response functions acquire non-zero imaginary part in an additional frequency range q u < φ< q v. The reversal of the sign of the electron polarizability in this new domain gives rise to a sharp plasmonic mode which is absent in the conventional RPA.

  2. Estimating Supply Response Function for Wheat: A Case Study

    Directory of Open Access Journals (Sweden)

    M.S. EI-Habbab

    2002-01-01

    Full Text Available To increase wheat production, governments can subsidize wheat farmers by purchasing their produce at a price higher than the world price. This policy did not succeed in increasing wheat production in the Irbid Governorate of Jordan, our case study area. The agricultural sector in the study area was characterized by risk in production and prices. In our study, the supply response function based on the Nerlovian Model was estimated for wheat produced in Irbid Governorate. Wheat area, in the model, was the dependent variable in the supply response function. The independent variables were: wheat planted area in Dunums in the current and previous year respectively, the weighted price of wheat in the previous year deflated by the Consumer Price Index (CPI, the holding fragmentation coefficient in the previous year, the yield risk, and the amount of rain in millimeters during the early months of the season (October, November, and December. The study reached the following conclusions: Firstly, holdings fragmentation was the major factor that negatively affects wheat production. Since the heritage system is the main factor that affects holding fragmentation, the policy makers need to find a way that can decrease this effect. Secondly, lagged weighted prices were found more suitable than the current weighted prices from an economic and statical point of view. Thirdly, the partial adjustment coefficient was low (i.e. less than one, which means that the farmers need more than one year to change their producing habits. Finally, the farmers were found to be risk-neutral, because their decisions depend mainly on the level and distribution of rainfall during the rainy season.

  3. Functional Associations by Response Overlap (FARO), a functional genomics approach matching gene expression phenotypes.

    Science.gov (United States)

    Nielsen, Henrik Bjørn; Mundy, John; Willenbrock, Hanni

    2007-08-01

    The systematic comparison of transcriptional responses of organisms is a powerful tool in functional genomics. For example, mutants may be characterized by comparing their transcript profiles to those obtained in other experiments querying the effects on gene expression of many experimental factors including treatments, mutations and pathogen infections. Similarly, drugs may be discovered by the relationship between the transcript profiles effectuated or impacted by a candidate drug and by the target disease. The integration of such data enables systems biology to predict the interplay between experimental factors affecting a biological system. Unfortunately, direct comparisons of gene expression profiles obtained in independent, publicly available microarray experiments are typically compromised by substantial, experiment-specific biases. Here we suggest a novel yet conceptually simple approach for deriving 'Functional Association(s) by Response Overlap' (FARO) between microarray gene expression studies. The transcriptional response is defined by the set of differentially expressed genes independent from the magnitude or direction of the change. This approach overcomes the limited comparability between studies that is typical for methods that rely on correlation in gene expression. We apply FARO to a compendium of 242 diverse Arabidopsis microarray experimental factors, including phyto-hormones, stresses and pathogens, growth conditions/stages, tissue types and mutants. We also use FARO to confirm and further delineate the functions of Arabidopsis MAP kinase 4 in disease and stress responses. Furthermore, we find that a large, well-defined set of genes responds in opposing directions to different stress conditions and predict the effects of different stress combinations. This demonstrates the usefulness of our approach for exploiting public microarray data to derive biologically meaningful associations between experimental factors. Finally, our results indicate

  4. Autonomic function responses to training: Correlation with body composition changes.

    Science.gov (United States)

    Tian, Ye; Huang, Chuanye; He, Zihong; Hong, Ping; Zhao, Jiexiu

    2015-11-01

    The causal relation between autonomic function and adiposity is an unresolved issue. Thus, we studied whether resting heart rate variability (HRV) changes could be used to predict changes in body composition after 16 weeks of individualized exercise training. A total of 117 sedentary overweight/obese adults volunteered to join an intervention group (IN, n=82) or a control group (CON, n=35). The intervention group trained for 30-40 min three times a week with an intensity of 85-100% of individual ventilatory threshold (Thvent). At baseline and after a 16-week training period, resting HRV variables, body composition and peak oxygen uptake (VO2peak) were assessed. Compared with CON, exercise training significantly improved HRV and body composition and increased VO2peak (Ptraining were observed for those with greater total and central fat loss. Individual aerobic-based exercise training was for improving autonomic function and resting HRV responses to aerobic training is a potential indicator for adaptations to exercise training. Copyright © 2015. Published by Elsevier Inc.

  5. Local structure and lattice dynamics study of low dimensional materials using atomic pair distribution function and high energy resolution inelastic x-ray scattering

    Science.gov (United States)

    Shi, Chenyang

    Structure and dynamics lie at the heart of the materials science. A detailed knowledge of both subjects would be foundational in understanding the materials' properties and predicting their potential applications. However, the task becomes increasingly dicult as the particle size is reduced to the nanometer scale. For nanostructured materials their laboratory x-ray scattering patterns are overlapped and broadened, making structure determination impossible. Atomic pair distribution function technique based on either synchrotron x-ray or neutron scattering data is known as the tool of choice for probing local structures. However, to solve the "structure problem" in low-dimensional materials with PDF is still challenging. For example for 2D materials of interest in this thesis the crystallographic modeling approach often yields unphysical thermal factors along stacking direction where new chemical intuitions about their actual structures and new modeling methodology/program are needed. Beyond this, lattice dynamical investigations on nanosized particles are extremely dicult. Laboratory tools such as Raman and infra-red only probe phonons at Brillouin zone center. Although in literature there are a great number of theoretical studies of their vibrational properties based on either empirical force elds or density functional theory, various approximations made in theories make the theoretical predictions less reliable. Also, there lacks the direct experiment result to validate the theory against. In this thesis, we studied the structure and dynamics of a wide variety of technologically relevant low-dimensional materials through synchrotron based x-ray PDF and high energy resolution inelastic x-ray scattering (HERIX) techniques. By collecting PDF data and employing advanced modeling program such as DiPy-CMI, we successfully determined the atomic structures of (i) emerging Ti3C2, Nb4C3 MXenes (transition metal carbides and/or nitrides) that are promising for energy storage

  6. Molecular dynamics of solutions of poly-3-octyl-thiophene and functionalized single wall carbon nanotubes studied by neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Díaz-Paniagua, Carlos [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Urbina, Antonio, E-mail: a.urbina@imperial.ac.uk [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Universidad Politécnica de Cartagena, Plaza del Hospital 1, 30202 Cartagena (Spain); García-Sakai, Victoria [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Seydel, Tilo [Institut Laue-Langevin, 39042 Grenoble Cedex (France); Abad, José; Padilla, Javier; García-Valverde, Rafael; Espinosa, Nieves [Universidad Politécnica de Cartagena, Plaza del Hospital 1, 30202 Cartagena (Spain); Gómez-Escalonilla, Marí a-José; Langa, Fernando [Instituto de Nanociencia, Nanotecnología y Materiales Moleculares (INAMOL), Universidad de Castilla-La Mancha, 45071 Toledo (Spain); Batallán, Francisco [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain)

    2013-12-12

    Highlights: • P3OT diffusion characteristic times in toluene solution at different temperatures have been obtained. • Gelation process for P3OT in solution has been demonstrated. • A methodology for elastic and quasielastic neutron scattering data analysis for liquids has been developed. - Abstract: Using both quasielastic and elastic window neutron spectroscopy, we study the molecular dynamics of poly-3-octyl-thiophene and of mixtures of carbon nanotube derivatives and poly-3-octyl-thiophene, both in deuterated toluene solutions. From the analysis of the experimental results of solutions for a broad range of concentrations, from very diluted to concentrated, different regimes of molecular motions are established, and a critical concentration between 2 and 3 wt% for the overlapping of macromolecules is obtained, including evidence of gelation processes for the higher concentrations driven by the entanglement of the macromolecules. Additionally, the temperature and momentum dependence of the characteristic times of the motions are obtained from the fit of the experimental data to stretched exponential models, delivering temperature dependent subnanosecond timescales for the diffusion of the macromolecule (0.02–0.5 ns)

  7. Graphene-Gold Nanoparticles Hybrid-Synthesis, Functionalization, and Application in a Electrochemical and Surface-Enhanced Raman Scattering Biosensor.

    Science.gov (United States)

    Khalil, Ibrahim; Julkapli, Nurhidayatullaili Muhd; Yehye, Wageeh A; Basirun, Wan Jefrey; Bhargava, Suresh K

    2016-05-24

    Graphene is a single-atom-thick two-dimensional carbon nanosheet with outstanding chemical, electrical, material, optical, and physical properties due to its large surface area, high electron mobility, thermal conductivity, and stability. These extraordinary features of graphene make it a key component for different applications in the biosensing and imaging arena. However, the use of graphene alone is correlated with certain limitations, such as irreversible self-agglomerations, less colloidal stability, poor reliability/repeatability, and non-specificity. The addition of gold nanostructures (AuNS) with graphene produces the graphene-AuNS hybrid nanocomposite which minimizes the limitations as well as providing additional synergistic properties, that is, higher effective surface area, catalytic activity, electrical conductivity, water solubility, and biocompatibility. This review focuses on the fundamental features of graphene, the multidimensional synthesis, and multipurpose applications of graphene-Au nanocomposites. The paper highlights the graphene-gold nanoparticle (AuNP) as the platform substrate for the fabrication of electrochemical and surface-enhanced Raman scattering (SERS)-based biosensors in diverse applications as well as SERS-directed bio-imaging, which is considered as an emerging sector for monitoring stem cell differentiation, and detection and treatment of cancer.

  8. Graphene–Gold Nanoparticles Hybrid—Synthesis, Functionalization, and Application in a Electrochemical and Surface-Enhanced Raman Scattering Biosensor

    Science.gov (United States)

    Khalil, Ibrahim; Julkapli, Nurhidayatullaili Muhd; Yehye, Wageeh A.; Basirun, Wan Jefrey; Bhargava, Suresh K.

    2016-01-01

    Graphene is a single-atom-thick two-dimensional carbon nanosheet with outstanding chemical, electrical, material, optical, and physical properties due to its large surface area, high electron mobility, thermal conductivity, and stability. These extraordinary features of graphene make it a key component for different applications in the biosensing and imaging arena. However, the use of graphene alone is correlated with certain limitations, such as irreversible self-agglomerations, less colloidal stability, poor reliability/repeatability, and non-specificity. The addition of gold nanostructures (AuNS) with graphene produces the graphene–AuNS hybrid nanocomposite which minimizes the limitations as well as providing additional synergistic properties, that is, higher effective surface area, catalytic activity, electrical conductivity, water solubility, and biocompatibility. This review focuses on the fundamental features of graphene, the multidimensional synthesis, and multipurpose applications of graphene–Au nanocomposites. The paper highlights the graphene–gold nanoparticle (AuNP) as the platform substrate for the fabrication of electrochemical and surface-enhanced Raman scattering (SERS)-based biosensors in diverse applications as well as SERS-directed bio-imaging, which is considered as an emerging sector for monitoring stem cell differentiation, and detection and treatment of cancer. PMID:28773528

  9. The spin-dependent structure function $g_1(x)$ of the proton from polarized deep-inelastic muon scattering

    CERN Document Server

    Adeva, B; Arvidson, A; Badelek, B; Bardin, G; Baum, G; Berglund, P; Betev, L; Birsa, R; De Botton, N R; Bradamante, Franco; Bravar, A; Bressan, A; Bültmann, S; Burtin, E; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Eichblatt, S; Fasching, D; Feinstein, F; Fernández, C; Forthmann, S; Frois, Bernard; Gallas, A; Garzón, J A; Gilly, H; Giorgi, M A; Görtz, S; Gracia, G; De Groot, N; Haft, K; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Kageya, T; Karev, A G; Ketel, T; Kiryluk, J; Kiselev, Yu F; Krivokhizhin, V G; Kröger, W; Kukhtin, V V; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Litmaath, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Meyer, W T; Van Middelkoop, G; Miller, D; Miyachi, Y; Mori, K; Moromisato, J H; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Grosse-Perdekamp, M; Pereira, H; Perrot-Kunne, F; Peshekhonov, V D; Pinsky, L; Platchkov, S K; Pló, M; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Rädel, G; Rijllart, A; Reicherz, G; Rodríguez, M; Rondio, Ewa; Roscherr, B; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schiller, A; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H B; Szleper, M; Tessarotto, F; Thers, D; Tlaczala, W; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Whitten, C; Windmolders, R; Wislicki, W; Witzmann, A; Ylöstalo, J; Zanetti, A M; Zaremba, K

    1997-01-01

    We present a new measurement of the virtual photon proton asymmetry $A_1^{\\rm p}$ from deep inelastic scattering of polarized muons on polarized protons in the kinematic range $0.0008 1$ GeV$^{2}$. A perturbative QCD evolution in next-to-leading order is used to determine $g_1^{\\rm p}(x)$ at a constant $Q^2$. At $Q^{2} = 10$ GeV$^{2}$ we find, in the measured range, $\\int_{0.003}^{0.7} g_{1}^{\\rm p}(x){\\rm d}x = 0.139 \\pm 0.006~({\\rm stat})\\pm 0.008~({\\rm syst)} \\pm 0.006~({\\rm evol})$. The value of the first moment $\\Gamma_{1}^{\\rm p} = \\int_{0}^{1} g_{1}^{\\rm p}(x){\\rm d}x$ of $g_{1}^{\\rm p}$ depends on the approach used to describe the behaviour of $g_{1}^{\\rm p}$ at low $x$. We find that the Ellis-Jaffe sum rule is violated. With our published result for $\\Gamma_{1}^{\\rm d}$ we confirm the Bjorken sum rule with an accuracy of $\\approx 15\\%$ at the one standard deviation level.

  10. Aerosol light scattering measurements as a function of relative humidity: a comparison between measurements made at three different sites

    Science.gov (United States)

    Day, Derek E.; Malm, William C.

    The water uptake by fine aerosol particles in the atmosphere has been investigated at three rural National Parks in the United States (Great Smoky Mountains, Grand Canyon and Big Bend National Parks). The relative humidity (RH) of sample aerosols was varied from less than 20% to greater than 90% using Perma Pure drying tubes as the scattering coefficient of the aerosol was measured with a Radiance Research M903 nephelometer. Data from these studies show that growth curves at all the three sites are similar in shape but the magnitude of growth can vary considerably from day to day. The growth curves from Great Smoky Mountains show smooth continuous growth over the entire range of RH, while the growth curves from the Grand Canyon and Big Bend show smooth and continuous growth on some days and deliquescence on other days. Comparing 12-h filter samples of chemical composition data with the aerosol growth curves, we find that higher fractions of soluble inorganic compounds (sulfate and nitrate) produce growth curves of greater magnitude than do higher concentrations of either organic carbon or soil material.

  11. Graphene–Gold Nanoparticles Hybrid—Synthesis, Functionalization, and Application in a Electrochemical and Surface-Enhanced Raman Scattering Biosensor

    Directory of Open Access Journals (Sweden)

    Ibrahim Khalil

    2016-05-01

    Full Text Available Graphene is a single-atom-thick two-dimensional carbon nanosheet with outstanding chemical, electrical, material, optical, and physical properties due to its large surface area, high electron mobility, thermal conductivity, and stability. These extraordinary features of graphene make it a key component for different applications in the biosensing and imaging arena. However, the use of graphene alone is correlated with certain limitations, such as irreversible self-agglomerations, less colloidal stability, poor reliability/repeatability, and non-specificity. The addition of gold nanostructures (AuNS with graphene produces the graphene–AuNS hybrid nanocomposite which minimizes the limitations as well as providing additional synergistic properties, that is, higher effective surface area, catalytic activity, electrical conductivity, water solubility, and biocompatibility. This review focuses on the fundamental features of graphene, the multidimensional synthesis, and multipurpose applications of graphene–Au nanocomposites. The paper highlights the graphene–gold nanoparticle (AuNP as the platform substrate for the fabrication of electrochemical and surface-enhanced Raman scattering (SERS-based biosensors in diverse applications as well as SERS-directed bio-imaging, which is considered as an emerging sector for monitoring stem cell differentiation, and detection and treatment of cancer.

  12. Central functional response to the novel peptide cannabinoid, hemopressin.

    Science.gov (United States)

    Dodd, Garron T; Worth, Amy A; Hodkinson, Duncan J; Srivastava, Raj K; Lutz, Beat; Williams, Steve R; Luckman, Simon M

    2013-08-01

    Hemopressin is the first peptide ligand to be described for the CB₁ cannabinoid receptor. Hemopressin acts as an inverse agonist in vivo and can cross the blood-brain barrier to both inhibit appetite and induce antinociception. Despite being highly effective, synthetic CB₁ inverse agonists are limited therapeutically due to unwanted, over dampening of central reward pathways. However, hemopressin appears to have its effect on appetite by affecting satiety rather than reward, suggesting an alternative mode of action which might avoid adverse side effects. Here, to resolve the neuronal circuitry mediating hemopressin's actions, we have combined blood-oxygen-level-dependent, pharmacological-challenge magnetic resonance imaging with c-Fos functional activity mapping to compare brain regions responsive to systemic administration of hemopressin and the synthetic CB₁ inverse agonist, AM251. Using these complementary methods, we demonstrate that hemopressin activates distinct neuronal substrates within the brain, focused mainly on the feeding-related circuits of the mediobasal hypothalamus and in nociceptive regions of the periaqueductal grey (PAG) and dorsal raphe (DR). In contrast to AM251, there is a distinct lack of activation of the brain reward centres, such as the ventral tegmental area, nucleus accumbens and orbitofrontal cortex, which normally form a functional activity signature for the central action of synthetic CB₁ receptor inverse agonists. Thus, hemopressin modulates the function of key feeding-related brain nuclei of the mediobasal hypothalamus, and descending pain pathways of the PAG and DR, and not higher limbic structures. Thus, hemopressin may offer behaviourally selective effects on nociception and appetite, without engaging reward pathways. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Scattering by Atmospheric Particles: From Aerosols to Clouds with the Point-Spread Function ... using Water, Milk, Plastic Cups, and a Laser Pointer

    Science.gov (United States)

    Davis, A. B.

    2015-12-01

    Planetary atmospheres are made primarily of molecules, and their optical properties are well known. They scatter sunlight across the spectrum, but far more potently at shorter wavelengths. Consequently, they redden the Sun as it sets and, at the same time, endow the daytime sky with its characteristic blue hue. There are also microscopic atmospheric particulates that are equally omnipresent because small enough (up to ~10s of microns) to remain lofted for long periods of time. However, in contrast with molecules of the major gases, their concentrations are highly variable in space and time. Their optical properties are also far more interesting. These airborne particles are either solid---hence the word "aerosols"---or liquid, most notably in the form of cloud droplets. Needless to say that both aerosols and clouds have major impacts on the balance of the Earth's climate system. Harder to understand, but nonetheless true, is that their climate impacts are much harder to assess by Earth system modelers than those of greenhouse gases such as CO2. That makes them prime targets of study by multiple approaches, including ground- and space-based remote sensing. To characterize aerosols and clouds quantitatively by optical remote sensing methods, either passive (sunlight-based) or active (laser-based), we need predictive capability for the signals recorded by sensors, whether ground-based, airborne, or carried by satellites. This in turn draws on the physical theory of "radiative transfer" that describes how the light propagates and scatters in the molecular-and-particulate atmosphere. This is a challenge for remote sensing scientists. I will show why by simulating with simple means the point spread function or "PSF" of scattering particulate atmospheres with varying opacity, thus covering tabletop analogs of the pristine air, the background aerosol, all the way to optically thick cloudy airmasses. I will also show PSF measurements of real clouds over New Mexico and

  14. Electromagnetic scattering theory

    Science.gov (United States)

    Bird, J. F.; Farrell, R. A.

    1986-01-01

    Electromagnetic scattering theory is discussed with emphasis on the general stochastic variational principle (SVP) and its applications. The stochastic version of the Schwinger-type variational principle is presented, and explicit expressions for its integrals are considered. Results are summarized for scalar wave scattering from a classic rough-surface model and for vector wave scattering from a random dielectric-body model. Also considered are the selection of trial functions and the variational improvement of the Kirchhoff short-wave approximation appropriate to large size-parameters. Other applications of vector field theory discussed include a general vision theory and the analysis of hydromagnetism induced by ocean motion across the geomagnetic field. Levitational force-torque in the magnetic suspension of the disturbance compensation system (DISCOS), now deployed in NOVA satellites, is also analyzed using the developed theory.

  15. Λ scattering equations

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Humberto [Instituto de Fisica - Universidade de São Paulo,Caixa Postal 66318, 05315-970 São Paulo, SP (Brazil); Facultad de Ciencias Basicas, Universidad Santiago de Cali,Calle 5 62-00 Barrio Pampalinda, Cali, Valle (Colombia)

    2016-06-17

    The CHY representation of scattering amplitudes is based on integrals over the moduli space of a punctured sphere. We replace the punctured sphere by a double-cover version. The resulting scattering equations depend on a parameter Λ controlling the opening of a branch cut. The new representation of scattering amplitudes possesses an enhanced redundancy which can be used to fix, modulo branches, the location of four punctures while promoting Λ to a variable. Via residue theorems we show how CHY formulas break up into sums of products of smaller (off-shell) ones times a propagator. This leads to a powerful way of evaluating CHY integrals of generic rational functions, which we call the Λ algorithm.

  16. Determination of diagnostic X ray spectra scattered by a phantom

    Energy Technology Data Exchange (ETDEWEB)

    Fehrenbacher, G.; Panzer, W.; Regulla, D. [GSF - National Research Center for Environment and Health, Neuherberg (Germany). Inst. of Radiation Protection; Tesfu, K. [Addis Ababa Univ. (Ethiopia)

    1997-12-01

    Photon spectra are reported that result from the scatter of diagnostic X rays at an appropriate water phantom that represents a patient. The tube voltages considered are between 52 kV and 110 kV, the scatter angles from 10{sup o} to 142{sup o} to the normal radiation incidence direction. All spectral measurements were performed with a high-purity germanium detector. Spectral photon fluences are computed from the measured pulse height distribution by using an unfolding procedure. The required response functions of the detection system were obtained by using Monte Carlo methods. Reference is made to a catalogue compiling 35 spectra of scattered X rays in diagnostics resulting from a human substitute, together with information on relevant primary field parameters as well as air kerma for the scattered X rays. (Author).

  17. Scattering theory

    CERN Document Server

    Friedrich, Harald

    2016-01-01

    This corrected and updated second edition of "Scattering Theory" presents a concise and modern coverage of the subject. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. The book contains sections on special topics such as near-threshold quantization, quantum reflection, Feshbach resonances and the quantum description of scattering in two dimensions. The level of abstraction is k...

  18. A ternary functional Ag@GO@Au sandwiched hybrid as an ultrasensitive and stable surface enhanced Raman scattering platform

    Science.gov (United States)

    Zhang, Cong-yun; Hao, Rui; Zhao, Bin; Hao, Yao-wu; Liu, Ya-qing

    2017-07-01

    The graphene-mediated surface enhanced Raman scattering (SERS) substrates by virtues of plasmonic metal nanostructures and graphene or its derivatives have attracted tremendous interests which are expected to make up the deficiency of traditional plasmonic metal substrates. Herein, we designed and fabricated a novel ternary Ag@GO@Au sandwich hybrid wherein the ultrathin graphene oxide (GO) films were seamlessly wrapped around the hierarchical flower-like Ag particle core and meanwhile provided two-dimensional anchoring scaffold for the coating of Au nanoparticles (NPs). The surface coverage density of loading Au NPs could be readily controlled by tuning the dosage amount of Au particle solutions. These features endowed the sandwiched structures high enrichment capability for analytes such as aromatic molecules and astonishing SERS performance. The Raman signals were enormously enhanced with an ultrasensitive detection limit of rhodamine-6G (R6G) as low as 10-13 M based on the chemical enhancement from GO and multi-dimensional plasmonic coupling between the metal nanoparticles. In addition, the GO interlayer as an isolating shell could effectively prevent the metal-molecule direct interaction and suppress the oxidation of Ag after exposure at ambient condition which enabled the substrates excellent reproducibility with less than 6% signal variations and prolonged life-time. To evaluate the feasibility and the practical application for SERS detection in real-world samples based on GO sandwiched hybrid as SERS-active substrate, three different prohibited colorants with a series of concentrations were measured with a minimum detected concentration down to 10-9 M. Furthermore, the prepared GO sandwiched nanostructures can be used to identify different types of colorants existing in red wine, implying the great potential applications for single-particle SERS sensing of biotechnology and on-site monitoring in food security.

  19. Investigation of chromophore-chromophore interaction by electro-optic measurements, linear dichroism, x-ray scattering, and density-functional calculations

    DEFF Research Database (Denmark)

    Apitz, Dirk; Bertram, R.P.; Benter, N.

    2005-01-01

    Free-beam interferometry and angle-resolved absorption spectra are used to investigate the linear electro-optic coefficients and the linear dichroism in photoaddressable bis-azo copolymer thin films. From the first- and second order parameters deduced, the chromophore orientation distribution is ...... by density-functional calculations support the picture of differently aligned bis-azo dye molecules in a trans,trans configuration. Complementary wide-angle x-ray scattering is recorded to confirm the various kinds of ordering in samples poled at different temperatures.......Free-beam interferometry and angle-resolved absorption spectra are used to investigate the linear electro-optic coefficients and the linear dichroism in photoaddressable bis-azo copolymer thin films. From the first- and second order parameters deduced, the chromophore orientation distribution...

  20. Measurement of the Inclusive e{\\pm}p Scattering Cross Section at High Inelasticity y and of the Structure Function FL

    CERN Document Server

    Aaron, F D; Andreev, V; Backovic, S; Baghdasaryan, A; Baghdasaryan, S; Barrelet, E; Bartel, W; Behrend, O; Belov, P; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Britzger, D; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bylinkin, A; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Ceccopieri, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cvach, J; Dainton, J B; Daum, K; Delcourt, B; Delvax, J; De Wolf, E A; Diaconu, C; Dobre, M; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Egli, S; Eliseev, A; Elsen, E; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Grebenyuk, A; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C.W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Huber, F; Jacquet, M; Janssen, X; Jonsson, L; Jung, A W; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Kostka, P; Kraemer, M; Kretzschmar, J; Kruger, K; Kutak, K; Landon, M P.J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Lendermann, V; Levonian, S; Lipka, K; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Makankine, A; Malinovski, E; Marage, P; Martyn, H U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, J; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Mudrinic, M; Muller, K; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nikitin, D; Nowak, G; Nowak, K; Olsson, J E; Osman, S; Ozerov, D; Pahl, P; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pirumov, H; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Radescu, V; Raicevic, N; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rusakov, S; Salek, D; Sankey, D P.C; Sauter, M; Sauvan, E; Schmitt, S; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, I; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, A; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sykora, T; Thompson, P D; Toll, T; Tran, T H; Traynor, D; Truol, P; Tsakov, I; Tseepeldorj, B; Tsurin, I; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas, A; Vazdik, Y; von den Driesch, M; Wegener, D; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zohrabyan, H; Zomer, F

    2011-01-01

    A measurement is presented of the inclusive neutral current e\\pm p scattering cross section using data collected by the H1 experiment at HERA during the years 2003 to 2007 with proton beam energies Ep of 920, 575, and 460 GeV. The kinematic range of the measurement covers low absolute four-momentum transfers squared, 1.5 GeV2 < Q2 < 120 GeV2, small values of Bjorken x, 2.9 \\cdot 10-5 < x < 0.01, and extends to high inelasticity up to y = 0.85. The structure function FL is measured by combining the new results with previously published H1 data at Ep = 920 GeV and Ep = 820 GeV. The new measurements are used to test several phenomenological and QCD models applicable in this low Q2 and low x kinematic domain.

  1. A validation of a ray-tracing tool used to generate bi-directional scattering distribution functions for complex fenestration systems

    DEFF Research Database (Denmark)

    McNeil, A.; Jonsson, C.J.; Appelfeld, David

    2013-01-01

    , or daylighting systems. However, such tools require users to provide bi-directional scattering distribution function (BSDF) data that describe the solar-optical performance of the CFS. A free, open-source Radiance tool genBSDF enables users to generate BSDF data for arbitrary CFS. Prior to genBSDF, BSDF data.......We explain the basis and use of the genBSDF tool and validate the tool by comparing results for four different cases to BSDF data produced via alternate methods. This validation demonstrates that BSDFs created with genBSDF are comparable to BSDFs generated analytically using TracePro and by measurement......Fenestration attachments are anticipated to produce significant reductions in building energy use because they can be deployed quickly at low-cost. New software tools enable users to assess the building energy impacts of optically complex fenestration systems (CFS) such as shades, Venetian blinds...

  2. Characterization of white poplar and eucalyptus after ionic liquid pretreatment as a function of biomass loading using X-ray diffraction and small angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Xueming [Beijing Univ. of Chemical Technology (China); Duan, Yonghao [Beijing Univ. of Chemical Technology (China); He, Lilin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Singh, Seema [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Simmons, Blake [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cheng, Gang [Beijing Univ. of Chemical Technology (China); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-02-08

    A systematic study was done to understand interactions among biomass loading during ionic liquid (IL) pretreatment, biomass type and biomass structures. White poplar and eucalyptus samples were pretreated using 1-ethyl-3-methylimidazolium acetate (EmimOAc) at 110 °C for 3 h at biomass loadings of 5, 10, 15, 20 and 25 wt%. All of the samples were chemically characterized and tested for enzymatic hydrolysis. Physical structures including biomass crystallinity and porosity were measured by X-ray diffraction (XRD) and small angle neutron scattering (SANS), respectively. SANS detected pores of radii ranging from ~25 to 625 Å, enabling assessment of contributions of pores with different sizes to increased porosity after pretreatment. Contrasting dependences of sugar conversion on white poplar and eucalyptus as a function of biomass loading were observed and cellulose crystalline structure was found to play an important role.

  3. Energy dependence of scatter components in multispectral PET imaging.

    Science.gov (United States)

    Bentourkia, M; Msaki, P; Cadorette, J; Lecomte, R

    1995-01-01

    High resolution images in PET based on small individual detectors are obtained at the cost of low sensitivity and increased detector scatter. These limitations can be partially overcome by enlarging discrimination windows to include more low-energy events and by developing more efficient energy-dependent methods to correct for scatter radiation from all sources. The feasibility of multispectral scatter correction was assessed by decomposing response functions acquired in multiple energy windows into four basic components: object, collimator and detector scatter, and trues. The shape and intensity of these components are different and energy-dependent. They are shown to contribute to image formation in three ways: useful (true), potentially useful (detector scatter), and undesirable (object and collimator scatter) information to the image over the entire energy range. With the Sherbrooke animal PET system, restoration of detector scatter in every energy window would allow nearly 90% of all detected events to participate in image formation. These observations suggest that multispectral acquisition is a promising solution for increasing sensitivity in high resolution PET. This can be achieved without loss of image quality if energy-dependent methods are made available to preserve useful events as potentially useful events are restored and undesirable events removed.

  4. Spectral element boundary integral method with periodic layered medium dyadic Green's function for multiscale nano-optical scattering analysis.

    Science.gov (United States)

    Niu, Jun; Ren, Yi; Liu, Qing Huo

    2017-10-02

    In this work, we propose a numerical solver combining the spectral element - boundary integral (SEBI) method with the periodic layered medium dyadic Green's function. The periodic layered medium dyadic Green's function is formulated under matrix representation. The surface integral equations (SIEs) are then implemented as the radiation boundary condition to truncate the top and bottom computation domain. After describing the interior computation domain with the vector wave equations, and treating the lateral boundaries with Bloch periodic boundary conditions, the whole computation domains are discretized with mixed-order Gauss- Lobatto-Legendre basis functions in the SEBI method. This method avoids the discretization of the top and bottom layered media, so it can be much more efficient than conventional methods. Numerical results validate the proposed solver with fast convergence throughout the whole computation domain and good performance for typical multiscale nano-optical applications.

  5. Response Functions to Critical Shocks in Social Sciences:

    Science.gov (United States)

    Roehner, B. M.; Sornette, D.; Andersen, J. V.

    We show that, provided one focuses on properly selected episodes, one can apply to the social sciences the same observational strategy that has proved successful in natural sciences such as astrophysics or geodynamics. For instance, in order to probe the cohesion of a society, one can, in different countries, study the reactions to some huge and sudden exogenous shocks, which we call Dirac shocks. This approach naturally leads to the notion of structural (as opposed or complementary to temporal) forecast. Although structural predictions are by far the most common way to test theories in the natural sciences, they have been much less used in the social sciences. The Dirac shock approach opens the way to testing structural predictions in the social sciences. The examples reported here suggest that critical events are able to reveal pre-existing "cracks" because they probe the social cohesion which is an indicator and predictor of future evolution of the system, and in some cases they foreshadow a bifurcation. We complement our empirical work with numerical simulations of the response function ("damage spreading") to Dirac shocks in the Sznajd model of consensus build-up. We quantify the slow relaxation of the difference between perturbed and unperturbed systems, the conditions under which the consensus is modified by the shock and the large variability from one realization to another.

  6. Executive Functioning at Baseline Prospectively Predicts Depression Treatment Response.

    Science.gov (United States)

    Dawson, Erica L; Caveney, Angela F; Meyers, Kortni K; Weisenbach, Sara L; Giordani, Bruno; Avery, Erich T; Schallmo, Michael-Paul; Bahadori, Armita; Bieliauskas, Linas A; Mordhorst, Matthew; Marcus, Sheila M; Kerber, Kevin; Zubieta, Jon-Kar; Langenecker, Scott A

    2017-02-09

    Existing cognitive and clinical predictors of treatment response to date are not of sufficient strength to meaningfully impact treatment decision making and are not readily employed in clinical settings. This study investigated whether clinical and cognitive markers used in a tertiary care clinic could predict response to usual treatment over a period of 4 to 6 months in a sample of 75 depressed adults. Patients (N = 384) were sequentially tested in 2 half-day clinics as part of a quality improvement project at an outpatient tertiary care center between August 2003 and September 2007; additional subjects evaluated in the clinic between 2007 and 2009 were also included. Diagnosis was according to DSM-IV-TR criteria and completed by residents and attending faculty. Test scores obtained at intake visits on a computerized neuropsychological screening battery were the Parametric Go/No-Go task and Facial Emotion Perception Task. Treatment outcome was assessed using 9-item Patient Health Questionnaire (PHQ-9) self-ratings at follow-up (n = 75). Usual treatment included psychotropic medication and psychotherapy. Decline in PHQ-9 scores was predicted on the basis of baseline PHQ-9 score and education, with neuropsychological variables entered in the second step. PHQ-9 scores declined by 46% at follow-up (56% responders). Using 2-step multiple regression, baseline PHQ-9 score (P ≤ .05) and education (P ≤ .01) were significant step 1 predictors of percent change in PHQ-9 follow-up scores. In step 2 of the model, faster processing speed with interference resolution (go reaction time) independently explained a significant amount of variance over and above variables in step 1 (12% of variance, P < .01), while other cognitive and affective skills did not. This 2-step model accounted for 28% of the variance in treatment change in PHQ-9 scores. Processing speed with interference resolution also accounted for 12% variance in treatment and follow-up attrition. Use of executive

  7. Elastic scattering of surface plasmon polaritons: Modeling and experiment

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Coello, V.

    1998-01-01

    Elastic (in-plane) scattering of surface plasmon polaritons (SPP's) is modeled by considering isotropic pointlike scatterers whose responses to the incident SPP field are phenomenologically related to their effective polarizabilities. Numerical simulations of single, double, and multiple scattering...... are presented for randomly situated scatterers showing the interplay between different orders of scattering and localization phenomena. Correlation between the scattering regimes and spatial Fourier spectra of the corresponding SPP intensity distributions is considered. Various optical microcomponents (e...

  8. Fingerprinting analysis of non-crystalline pharmaceutical compounds using high energy X-rays and the total scattering pair distribution function

    Science.gov (United States)

    Davis, Timur D.

    2011-12-01

    In the development of new medicinal products, poor oral bioavailability, due to the low solubilities of many active pharmaceutical ingredients (APIs), is increasingly a barrier for treatments to be administered using tablet or capsule formulations and one of the main challenges facing the pharmaceutical industry. Non-crystalline phases such as the amorphous and nanostructured states can confer increased solubility to a drug, and therefore, have recently garnered a lot of interest from pharmaceutical researchers. However, little is known about local ordering in non-crystalline pharmaceuticals due to the lack of reliable experimental probes, hindering the clinical application of these compounds. The powerful tools of crystallography begin to lose their potency for structures on the nanoscale; conventional X-ray powder diffraction (XRPD) patterns become broad and featureless in these cases and are not useful for differentiating between different local molecular packing arrangements. In this thesis, we introduce the use of high energy X-rays coupled with total scattering pair distribution function (TSPDF) and fingerprinting analysis to investigate the local structures of non-crystalline pharmaceutical compounds. The high energy X-rays allow us to experimentally collect diffuse scattering intensities, which contain information about a sample's local ordering, in addition to the Bragg scattering available in conventional XRPD experiments, while the TSPDF allows us to view the intra- and inter-molecular correlations in real space. The goal of this study was to address some fundamental problems involving fingerprinting non-crystalline APIs using TSPDF in order to lay the groundwork for the proper use of the technique by the pharmaceutical community. We achieved this by developing the methodology as well as the exploring the scientific implications. On the methodology side, we introduced PDFGetX3, a new software program for calculating TSPDFs that simplifies the procedure

  9. Barrier distributions and scattering

    Energy Technology Data Exchange (ETDEWEB)

    Timmers, H.; Leigh, J.R.; Dasgupta, M.; Hinde, D.J.; Mein, J.C.; Morton, C.R.; Newton, J.O. [Department of Nuclear Physics, Australian National University, Canberra, ACT 0200 (Austria); Rowley, N. [Centre de Recherches Nucleaires, 23 Rue du Loess, F-67037 Strasbourg CEDEX 2 (France); Stefanini, A.M.; Ackermann, D.; Corradi, L.; He, J.H. [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Beghini, S.; Montagnoli, G.; Scarlassara, F.; Segato, G.F. [Universita di Padova and INFN Sezione di Padova, Padova (Italy)

    1997-10-01

    The extraction of representations of the fusion barrier distribution from backward-angle, quasi-elastic, elastic and transfer excitation functions is discussed. Such excitation functions have been measured for {sup 16}O, {sup 32}S and {sup 40}Ca projectiles incident on a variety of targets. The results are compared with representations obtained from fusion excitation functions. Varying in their sensitivity, all representations show evidence of the barrier structure. Differences between the scattering and the fusion representations can be related to the effects of coupling to residual, weak reaction channels. (author)

  10. Incorporating quantitative single photon emission computed tomography into radiation therapy treatment planning for lung cancer: impact of attenuation and scatter correction on the single photon emission computed tomography-weighted mean dose and functional lung segmentation.

    Science.gov (United States)

    Yin, Lingshu; Shcherbinin, Sergey; Celler, Anna; Thompson, Anna; Fua, Tsien-Fei; Liu, Mitchell; Duzenli, Cheryl; Gill, Brad; Sheehan, Finbar; Powe, John; Worsley, Daniel; Marks, Lawrence; Moiseenko, Vitali

    2010-10-01

    To assess the impact of attenuation and scatter corrections on the calculation of single photon emission computed tomography (SPECT)-weighted mean dose (SWMD) and functional volume segmentation as applied to radiation therapy treatment planning for lung cancer. Nine patients with lung cancer underwent a SPECT lung perfusion scan. For each scan, four image sets were reconstructed using the ordered subsets expectation maximization method with attenuation and scatter corrections ranging from none to a most comprehensive combination of attenuation corrections and direct scatter modeling. Functional volumes were segmented in each reconstructed image using 10%, 20%, …, 90% of maximum SPECT intensity as a threshold. Systematic effects of SPECT reconstruction methods on treatment planning using functional volume were studied by calculating size and spatial agreements of functional volumes, and V(20) for functional volume from actual treatment plans. The SWMD was calculated for radiation beams with a variety of possible gantry angles and field sizes. Functional volume segmentation is sensitive to the particular method of SPECT reconstruction used. Large variations in functional volumes, as high as >50%, were observed in SPECT images reconstructed with different attenuation/scatter corrections. However, SWMD was less sensitive to the type of scatter corrections. SWMD was consistent within 2% for all reconstructions as long as computed tomography-based attenuation correction was used. When using perfusion SPECT images during treatment planning optimization/evaluation, the SWMD may be the preferred figure of merit, as it is less affected by reconstruction technique, compared with threshold-based functional volume segmentation. 2010 Elsevier Inc. All rights reserved.

  11. Determination of gold nanoparticles in environmental water samples by second-order optical scattering using dithiotreitol-functionalized CdS quantum dots after cloud point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Mandyla, Spyridoula P.; Tsogas, George Z.; Vlessidis, Athanasios G.; Giokas, Dimosthenis L., E-mail: dgiokas@cc.uoi.gr

    2017-02-05

    Highlights: • A new method has been developed to determine gold nanoparticles in water samples. • Extraction was achieved by cloud point extraction. • A nano-hybrid assembly between AuNPs and dithiol-coated quantum dots was formulated. • Detection was accomplished at pico-molar levels by second-order light scattering. • The method was selective against ionic gold and other nanoparticle species. - Abstract: This work presents a new method for the sensitive and selective determination of gold nanoparticles in water samples. The method combines a sample preparation and enrichment step based on cloud point extraction with a new detection motif that relies on the optical incoherent light scattering of a nano-hybrid assembly that is formed by hydrogen bond interactions between gold nanoparticles and dithiotreitol-functionalized CdS quantum dots. The experimental parameters affecting the extraction and detection of gold nanoparticles were optimized and evaluated to the analysis of gold nanoparticles of variable size and surface coating. The selectivity of the method against gold ions and other nanoparticle species was also evaluated under different conditions reminiscent to those usually found in natural water samples. The developed method was applied to the analysis of gold nanoparticles in natural waters and wastewater with satisfactory results in terms of sensitivity (detection limit at the low pmol L{sup −1} levels), recoveries (>80%) and reproducibility (<9%). Compared to other methods employing molecular spectrometry for metal nanoparticle analysis, the developed method offers improved sensitivity and it is easy-to-operate thus providing an additional tool for the monitoring and the assessment of nanoparticles toxicity and hazards in the environment.

  12. Small Angle Neutron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Urban, Volker S [ORNL

    2012-01-01

    Small Angle Neutron Scattering (SANS) probes structural details at the nanometer scale in a non-destructive way. This article gives an introduction to scientists who have no prior small-angle scattering knowledge, but who seek a technique that allows elucidating structural information in challenging situations that thwart approaches by other methods. SANS is applicable to a wide variety of materials including metals and alloys, ceramics, concrete, glasses, polymers, composites and biological materials. Isotope and magnetic interactions provide unique methods for labeling and contrast variation to highlight specific structural features of interest. In situ studies of a material s responses to temperature, pressure, shear, magnetic and electric fields, etc., are feasible as a result of the high penetrating power of neutrons. SANS provides statistical information on significant structural features averaged over the probed sample volume, and one can use SANS to quantify with high precision the structural details that are observed, for example, in electron microscopy. Neutron scattering is non-destructive; there is no need to cut specimens into thin sections, and neutrons penetrate deeply, providing information on the bulk material, free from surface effects. The basic principles of a SANS experiment are fairly simple, but the measurement, analysis and interpretation of small angle scattering data involves theoretical concepts that are unique to the technique and that are not widely known. This article includes a concise description of the basics, as well as practical know-how that is essential for a successful SANS experiment.

  13. Critical fluid light scattering

    Science.gov (United States)

    Gammon, Robert W.

    1988-01-01

    The objective is to measure the decay rates of critical density fluctuations in a simple fluid (xenon) very near its liquid-vapor critical point using laser light scattering and photon correlation spectroscopy. Such experiments were severely limited on Earth by the presence of gravity which causes large density gradients in the sample when the compressibility diverges approaching the critical point. The goal is to measure fluctuation decay rates at least two decades closer to the critical point than is possible on earth, with a resolution of 3 microK. This will require loading the sample to 0.1 percent of the critical density and taking data as close as 100 microK to the critical temperature. The minimum mission time of 100 hours will allow a complete range of temperature points to be covered, limited by the thermal response of the sample. Other technical problems have to be addressed such as multiple scattering and the effect of wetting layers. The experiment entails measurement of the scattering intensity fluctuation decay rate at two angles for each temperature and simultaneously recording the scattering intensities and sample turbidity (from the transmission). The analyzed intensity and turbidity data gives the correlation length at each temperature and locates the critical temperature. The fluctuation decay rate data from these measurements will provide a severe test of the generalized hydrodynamic theories of transport coefficients in the critical regions. When compared to equivalent data from binary liquid critical mixtures they will test the universality of critical dynamics.

  14. Polyester textile functionalization through incorporation of pH/thermo-responsive microgels. Part II: polyester functionalization and characterization

    NARCIS (Netherlands)

    Glampedaki, P.; Calvimontes, A.; Dutschk, Victoria; Warmoeskerken, Marinus

    2012-01-01

    A new approach to functionalize the surface of polyester textiles is described in this study. Functionalization was achieved by incorporating pH/temperature-responsive polyelectrolyte microgels into the textile surface layer using UV irradiation. The aim of functionalization was to regulate

  15. Design and construction of a spectrometer facility and experiment for intermediate energy proton scattering on helium. [Wave functions, preliminary experimental techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rolfe, R.M.

    1976-12-01

    The goal of the research was to investigate proton scattering on nuclei at intermediate energies and in particular to investigate proton scattering on helium. A theoretical investigation of the helium nucleus and the nature of the intermediate energy interaction, design and optimization of an energy-loss spectrometer facility for proton-nucleus scattering, and the unique superfluid helium target and experimental design are discussed.

  16. Reflectance near-infrared measurements for determining changes in skin barrier function and scattering in relation to moisturizer application

    Science.gov (United States)

    Qassem, Meha; Kyriacou, Panayiotis A.

    2015-09-01

    Skin moisture relates to the state of multiple skin constituents and aspects, but unfortunately, a device which could provide comprehensive and in vivo analysis is not available. Nevertheless, several reports have demonstrated accurate estimations of dermal water content using near-infrared spectroscopy (NIRS), and the potential of employing this technique in skin analysis. We aim to investigate whether NIRS could detect changes in skin barrier function through evaluation of skin water uptake in relation to moisturizer application. NIR and capacitance data were collected from 20 volunteers at both forearms, prior to and after seven days of regular moisturizer use. Results indicated lower peak intensities at the 1940-nm minima and higher intensities at the 1450-nm equivalent minima with moisturizer abstinence, while the opposite was true with regular moisturizer application. As the light beam would have traveled deeper into the skin at 1450 nm, it has been concluded that long-term, frequent moisturizer use had limited the penetration of extrinsic water. Partial least squares analysis showed that separation of sample's scores increased with abstinence of moisturizer use. Thus, NIRS can provide valuable information not only on dermal water contents but also on additional parameters such as skin barrier function.

  17. Functional Associations by Response Overlap (FARO), a functional genomics approach matching gene expression phenotypes

    DEFF Research Database (Denmark)

    Nielsen, Henrik Bjørn; Mundy, J.; Willenbrock, Hanni

    2007-01-01

    including treatments, mutations and pathogen infections. Similarly, drugs may be discovered by the relationship between the transcript profiles effectuated or impacted by a candidate drug and by the target disease. The integration of such data enables systems biology to predict the interplay between...... experimental factors affecting a biological system. Unfortunately, direct comparisons of gene expression profiles obtained in independent, publicly available microarray experiments are typically compromised by substantial, experiment-specific biases. Here we suggest a novel yet conceptually simple approach...... to confirm and further delineate the functions of Arabidopsis MAP kinase 4 in disease and stress responses. Furthermore, we find that a large, well-defined set of genes responds in opposing directions to different stress conditions and predict the effects of different stress combinations. This demonstrates...

  18. A temperature response function for development of the chrysanthemum (Chrysanthemum x morifolium Ramat.

    Directory of Open Access Journals (Sweden)

    Streck Nereu Augusto

    2004-01-01

    Full Text Available Developmental models can help growers to decide management practices, and to predict flowering and harvest time. Currently, a double exponential function is proposed as a generalized temperature response function for chrysanthemum. This function is not the most appropriate because its parameters lack biological meaning. The objective of this study was to develop a nonlinear temperature response function of chrysanthemum development that has parameters with biological meaning. The proposed function is a beta function with three parameters, the cardinal temperatures (minimum, optimum, and maximum temperatures for development, which were defined as 0, 22, and 35ºC. Published data of temperature response of development of three cultivars, which are independent data sets, were used to test the performance of the double exponential function and the beta function. Results showed that the beta function is better than the double exponential function to describe the temperature response of chrysanthemum development.

  19. Self-intermediate scattering function of strongly interacting three-dimensional lattice gases: time- and wave-vector-dependent tracer diffusion coefficient.

    Science.gov (United States)

    Skarpalezos, Loukas; Argyrakis, Panos; Vikhrenko, Vyacheslav S

    2014-05-01

    We investigate the self-intermediate scattering function (SISF) in a three-dimensional (3D) cubic lattice fluid (interacting lattice gas) with attractive nearest-neighbor interparticle interactions at a temperature slightly above the critical one by means of Monte Carlo simulations. A special representation of SISF as an exponent of the mean tracer diffusion coefficient multiplied by the geometrical factor and time is considered to highlight memory effects that are included in time and wave-vector dependence of the diffusion coefficient. An analytical expression for the diffusion coefficient is suggested to reproduce the simulation data. It is shown that the particles' mean-square displacement is equal to the time integral of the diffusion coefficient. We make a comparison with the previously considered 2D system on a square lattice. The main difference with the two-dimensional case is that the time dependence of particular characteristics of the tracer diffusion coefficient in the 3D case cannot be described by exponentially decreasing functions, but requires using stretched exponentials with rather small values of exponents, of the order of 0.2. The hydrodynamic values of the tracer diffusion coefficient (in the limit of large times and small wave vectors) defined through SIFS simulation results agree well with the results of its direct determination by the mean-square displacement of the particles in the entire range of concentrations and temperatures.

  20. Function-weighted frequency response function sensitivity method for analytical model updating

    Science.gov (United States)

    Lin, R. M.

    2017-09-01

    Since the frequency response function (FRF) sensitivity method was first proposed [26], it has since become a most powerful and practical method for analytical model updating. Nevertheless, the original formulation of the FRF sensitivity method does suffer the limitation that the initial analytical model to be updated should be reasonably close to the final updated model to be sought, due the assumed mathematical first order approximation implicit to most sensitivity based methods. Convergence to correct model is not guaranteed when large modelling errors exist and blind application often leads to optimal solutions which are truly sought. This paper seeks to examine all the important numerical characteristics of the original FRF sensitivity method including frequency data selection, numerical balance and convergence performance. To further improve the applicability of the method to cases of large modelling errors, a new novel function-weighted sensitivity method is developed. The new method has shown much superior performance on convergence even in the presence of large modelling errors. Extensive numerical case studies based on a mass-spring system and a GARTEUR structure have been conducted and very encouraging results have been achieved. Effect of measurement noise has been examined and the method works reasonably well in the presence of measurement uncertainties. The new method removes the restriction of modelling error magnitude being of second order in Euclidean norm as compared with that of system matrices, thereby making it a truly general method applicable to most practical model updating problems.

  1. Listeners' Response to Music as a Function of Personality Type.

    Science.gov (United States)

    Lewis, Barbara E.; Schmidt, Charles P.

    1991-01-01

    Presents findings of research concerning the relationship between listener response to music and personality variables. Reports that correlations were found among undergraduate music appreciation students between the Music Listener Response Scale and sensing intuition for the entire group and between judgment perception and the scale among…

  2. Perceptions of Corporate Social Responsibility: Differences Across Industries and Functions.

    Science.gov (United States)

    Hamilton, John W.; And Others

    The concept of social responsibility as applied to business suggests that the corporation no longer has a responsibility only to the stockholder but must make decisions aimed toward balancing the interests of all clientele groups affected by actions of the corporation. These groups include managers, administrators, employees, and the general…

  3. Heavy-ion nucleus scattering

    CERN Document Server

    Rahman, M A; Haque, S

    2003-01-01

    Heavy ion-nucleus scattering is an excellent laboratory to probe high spin phenomena, exotic nuclei and for the analysis of various exit channels. The Strong Absorption Model or the generalized diffraction models, which are semi-classical in nature, have been employed in the description of various heavy ion-nucleus scattering phenomena with reasonable success. But one needs to treat the deflection function (scattering angles) quantum mechanically in the Wave Mechanical picture for the appropriate description of the heavy-ion nucleus scattering phenomena. We have brought the mathematics for the cross-section of the heavy-ion nucleus scattering to an analytic expression taking account of the deflection function (scattering angles) quantum mechanically. sup 9 Be, sup 1 sup 6 O, sup 2 sup 0 Ne and sup 3 sup 2 S heavy-ion beams elastic scattering from sup 2 sup 8 Si, sup 2 sup 4 Mg and sup 4 sup 0 Ca target nuclei at various projectile energies over the range 20-151 MeV have been analysed in terms of the 2-paramet...

  4. Time-Reversal Analysis for Scatterer Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, D H; Berryman, J G

    2003-11-05

    Only the simplest monopole scattering behavior has usually been treated in previous time-reversal analyses. A new application of time-reversal processing of wave scattering data permits characterization of scatterers by analyzing the number and nature of the singular functions (or eigenfunctions) associated with individual scatterers when they have multiple contributions from monopole, dipole and/or quadrupole scattering terms. We discuss acoustic, elastic, and electromagnetic scattering problems for low frequencies (ka < 1, k being the wavenumber and a the radius of the scatterer). Specific examples for electromagnetic scattering from one of a number of small conducting spheres show that each sphere can have up to six distinct time-reversal eigenfunctions associated with it.

  5. Doping Liquid Crystal Cells with Photocurable Monomer via Holographic Exposure to Realize Optical-Scattering-Free Infrared Phase Modulators with Fast Response Time

    Directory of Open Access Journals (Sweden)

    Chun-Yu Chien

    2017-07-01

    Full Text Available Photocurable monomer-doped liquid crystal (LC cells were processed via holographic exposure using a low-power He–Ne laser to generate holographic polymer networks. The polymer network LC (PNLC cells are used to fabricate infrared phase modulators at 1550 nm wavelength possessing favorable electro-optical performance. Compared with our previous work, the percentages of ingredients in the LC mixture filled in PNLC cells underwent a slight change. The 2 wt% concentration of anisotropic monomer RM257 were in place of isotropic monomer N–vinyl–2–pyrrolidinone (NVP. As a result, the fabricated phase modulators also maintained well homogeneous LC alignments and optical-scattering-free characteristics. Furthermore, NVP dopant successfully reduced the operating voltages from 95 Vrms to 79 Vrms to prevent polymer network deformation when electrically operating with higher voltages. The fabricated infrared phase modulators had a good average response time (i.e., rising time of 0.88 ms and falling time of 0.40 ms.

  6. The adaptative response of jaw muscles to varying functional demands

    NARCIS (Netherlands)

    Grünheid, T.; Langenbach, G.E.J.; Korfage, J.A.M.; Zentner, A.; van Eijden, T.M.G.J.

    2009-01-01

    Jaw muscles are versatile entities that are able to adapt their anatomical characteristics, such as size, cross-sectional area, and fibre properties, to altered functional demands. The dynamic nature of muscle fibres allows them to change their phenotype to optimize the required contractile function

  7. Structure, function and networks of transcription factors involved in abiotic stress responses

    DEFF Research Database (Denmark)

    Lindemose, Søren; O'Shea, Charlotte; Jensen, Michael Krogh

    2013-01-01

    Transcription factors (TFs) are master regulators of abiotic stress responses in plants. This review focuses on TFs from seven major TF families, known to play functional roles in response to abiotic stresses, including drought, high salinity, high osmolarity, temperature extremes...

  8. Functional characterization of Foxp3-specific spontaneous immune responses

    DEFF Research Database (Denmark)

    Larsen, Susanne Købke; Munir, S; Andersen, Anders Woetmann

    2013-01-01

    Tumor-infiltrating CD4+CD25+ regulatory T cells (Tregs) are associated with an impaired prognosis in several cancers. The transcription factor forkhead box P3 (Foxp3) is generally expressed in Tregs. Here, we identify and characterize spontaneous cytotoxic immune responses to Foxp3-expressing cells...... in peripheral blood of healthy volunteers and cancer patients. These immune responses were directed against a HLA-A2-restricted peptide epitope derived from Foxp3. Foxp3-reactive T cells were characterized as cytotoxic CD8+ T cells. These cells recognized dendritic cells incubated with recombinant Foxp3 protein...... readily killed by the Foxp3-specific cytotoxic T lymphocytes. The spontaneous presence of Foxp3-specific cytotoxic T-cell responses suggest a general role of such T cells in the complex network of immune regulation as such responses may eliminate Tregs, that is, suppression of the suppressors...

  9. Functional analysis of molecular interactions in synthetic auxin response circuits

    OpenAIRE

    Pierre-Jerome, Edith; Moss, Britney L.; Lanctot, Amy; Hageman, Amber; Nemhauser, Jennifer L.

    2016-01-01

    Auxin-regulated transcription plays a role in almost every aspect of plant growth and development. Recent structural studies of domains from auxin-activated transcription factors and auxin-degraded repressors have raised fundamental questions about the protein complexes required for auxin response. Here, we leverage the power of a synthetic yeast system to identify and systematically characterize the simplest auxin response unit in the absence of the potentially confounding influence of other...

  10. Response of the Lower Ionosphere to the Partial Solar Eclipses of August 1, 2008 and March 20, 2015 Based on Observations of Radio-Wave Scattering by the Ionospheric Plasma Irregularities

    Science.gov (United States)

    Bakhmet'eva, N. V.; Bubukina, V. N.; Vyakhirev, V. D.; Kalinina, E. E.; Komrakov, G. P.

    2017-03-01

    The results of observations of the ionospheric effects of the partial solar eclipses on August 1, 2008 and March 20, 2015 are presented. The observations were performed by the partial-reflection technique during scattering of radio waves by natural irregularities in the D region and the method of resonant scattering of radio waves by artificial periodic irregularities of the ionospheric plasma. A three- to fivefold reduction of the electron density in the D region was obtained by the partialreflection technique. Ionospheric response at altitudes above 88 km is delayed by 20-25 min relative to the time of the maximum eclipse phase, while in the bottom D region the time delay is a few minutes. Variations in the characteristics of the signals scattered by artificial periodic irregularities, as well as velocities of the vertical motion of the plasma in the lower ionosphere during the solar eclipse were studied. An increase in the scattered-signal amplitude during an eclipse in the E region by 30-40 dB was recorded, stratification of the D region was observed, and the appearance of signals scattered at the mesopause altitudes was detected.

  11. Coulomb correction to elastic. alpha. -. alpha. scattering

    Energy Technology Data Exchange (ETDEWEB)

    Bera, P.K.; Jana, A.K.; Haque, N.; Talukdar, B. (Department of Physics, Visva-Bharati University, Santiniketan-731235, West Bengal, India (IN))

    1991-02-01

    The elastic {alpha}-{alpha} scattering is treated within the framework of a generalized phase-function method (GPFM). This generalization consists in absorbing the effect of Coulomb interaction in the comparison functions for developing the phase equation. Based on values of scattering phase shifts computed by the present method, it is concluded that the GPFM provides an uncomplicated approach to rigorous Coulomb correction in the {alpha}-{alpha} scattering.

  12. Measurement of the inclusive e{sup {+-}}p scattering cross section at high inelasticity y and of the structure function F{sub L}

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Inst., Yerevan (Armenia); Barrelet, E. [CNRS/IN2P3, LPNHE, Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris 7, Paris (France); Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Cholewa, A.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Grell, B.R.; Habib, S.; Haidt, D.; Helebrant, C.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nikiforov, A.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Piec, S.; Pitzl, D.; Schmitt, S.; Sefkow, F.; South, D.; Staykova, Z.; Steder, M.; Toll, T.; Vargas, A.; Driesch, M. von den; Wuensch, E. [DESY, Hamburg (Germany); Behrend, O.; Wegener, D. [TU Dortmund, Inst. fuer Physik, Dortmund (Germany); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [CNRS/IN2P3, LAL, Univ. Paris-Sud, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [CNRS/IN2P3, LLR, Ecole Polytechnique, Palaiseau (France); Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I. [Univ. of Belgrade, Vinca Inst. of Nuclear Sciences, Belgrade (RS)] [and others

    2011-03-15

    A measurement is presented of the inclusive neutral current e{sup {+-}}p scattering cross section using data collected by the H1 experiment at HERA during the years 2003 to 2007 with proton beam energies E{sub p} of 920, 575, and 460 GeV. The kinematic range of the measurement covers low absolute four-momentum transfers squared, 1.5 GeV{sup 2}function F{sub L} is measured by combining the new results with previously published H1 data at E{sub p} =920 GeV and E{sub p} =820 GeV. The new measurements are used to test several phenomenological and QCD models applicable in this low Q{sup 2} and low x kinematic domain. (orig.)

  13. Direct extraction of QCD {lambda}{sub MS-bar} from moments of structure functions in neutrino-nucleon scattering, using the CORGI approach

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, C.J. E-mail: c.j.maxwell@durham.ac.uk; Mirjalili, A. E-mail: a.mirjalili@yazduni.ac.ir

    2002-11-25

    We use recently calculated next-to-next-to-leading anomalous dimension coefficients for the n=1,3,5,...,13 moments of the xF{sub 3} structure function in {nu}N scattering, together with the corresponding three-loop Wilson coefficients, to obtain improved QCD predictions for the moments. The Complete Renormalization Group Improvement (CORGI) approach is used, in which all dependence on renormalization or factorization scales is avoided by a complete resummation of ultraviolet logarithms. The Bernstein Polynomial method is used to compare these QCD predictions to the xF{sub 3} data of the CCFR Collaboration, and direct fits for {lambda}{sub MS-bar}{sup (5)}, with N{sub f}=5 effective quark flavours, over the range 20

  14. Amorphous Analogs of Martian Global Soil: Pair Distribution Function Analyses and Implications for Scattering Models of Chemin X-ray Diffraction Data

    Science.gov (United States)

    Achilles, C. N.; Bish, D. L.; Rampe, E. B.; Morris, R. V.

    2015-01-01

    Soils on Mars have been analyzed by the Mars Exploration Rovers (MER) and most recently by the Mars Science Laboratory (MSL) rover. Chemical analyses from a majority of soil samples suggest that there is a relatively uniform global soil composition across much of the planet. A soil site, Rocknest, was sampled by the MSL science payload including the CheMin X-ray diffractometer and the Alpha Particle X-ray Spectrometer (APXS). Che- Min X-ray diffraction (XRD) data revealed crystalline phases and a broad, elevated background, indicating the presence of amorphous or poorly ordered materials (Fig 1). Based on the chemical composition of the bulk soil measured by APXS and the composition of crystalline phases derived from unit-cell parameters determined with CheMin data, the percentages of crystalline and amorphous phases were calculated at 51% and 49%, respectively. Attempts to model the amorphous contribution to CheMin XRD patterns were made using amorphous standards and full-pattern fitting methods and show that the broad, elevated background region can be fitted by basaltic glass, allophane, and palagonite. However, the modeling shows only that these phases have scattering patterns similar to that for the soil, not that they represent unique solutions. Here, we use pair distribution function (PDF) analysis to determine the short-range order of amorphous analogs in martian soils and better constrain the amorphous material detected by CheMin.

  15. Measurement of the inclusive e{sup {+-}}p scattering cross section at high inelasticity y and of the structure function F{sub L}

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2010-12-15

    A measurement is presented of the inclusive neutral current e{sup {+-}}p scattering cross section using data collected by the H1 experiment at HERA during the years 2003 to 2007 with proton beam energies E{sub p} of 920, 575, and 460 GeV. The kinematic range of the measurement covers low absolute four-momentum transfers squared, 1.5 GeV{sup 2} < Q{sup 2} < 120 GeV{sup 2}, small values of Bjorken x, 2.9 . 10{sup -5} < x < 0.01, and extends to high inelasticity up to y=0.85. The structure function FL is measured by combining the new results with previously published H1 data at E{sub p} = 920 GeV and E{sub p} = 820 GeV. The new measurements are used to test several phenomenological and QCD models applicable in this low Q{sup 2} and low x kinematic domain. (orig.)

  16. Measurement of the Spin Structure Function of the Neutron G1(N) from Deep Inelastic Scattering of Polarized Electrons from Polarized Neutrons in He-3

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, J

    2004-01-06

    Polarized electrons of energies 19.42, 22.67, and 25.5 GeV were scattered off a polarized {sup 3}He target at SLAC's End Station A to measure the spin asymmetry of the neutron. From this asymmetry, the spin dependent structure function g{sub 1}{sup n}(x) was determined over a range in x from 0.03 to 0.6 with an average Q{sup 2} of 2 (GeV/C){sup 2}. The value of the integral of g{sub 1}{sup n} over x is {integral}g{sub 1}{sup n}(x)dx = -0.036 {+-} 0.009. The results were interpreted in the frame work of the Quark Parton Model (QPM) and used to test the Ellis-Jaffe and Bjorken sum rules. The value of the integral is 2.6 standard deviations from the Ellis-Jaffe prediction while the Bjorken sum rule was found to be in agreement with this data and proton data from SMC and E-143.

  17. Characterization of the CO2 fluid adsorption in coal as a function of pressure using neutron scattering techniques (SANS and USANS)

    Science.gov (United States)

    Melnichenko, Y.B.; Radlinski, A.P.; Mastalerz, Maria; Cheng, G.; Rupp, J.

    2009-01-01

    Small angle neutron scattering techniques have been applied to investigate the phase behavior of CO2 injected into coal and possible changes in the coal pore structure that may result from this injection. Three coals were selected for this study: the Seelyville coal from the Illinois Basin (Ro = 0.53%), Baralaba coal from the Bowen Basin (Ro = 0.67%), and Bulli 4 coal from the Sydney Basin (Ro = 1.42%). The coals were selected from different depths to represent the range of the underground CO2 conditions (from subcritical to supercritical) which may be realized in the deep subsurface environment. The experiments were conducted in a high pressure cell and CO2 was injected under a range of pressure conditions, including those corresponding to in-situ hydrostatic subsurface conditions for each coal. Our experiments indicate that the porous matrix of all coals remains essentially unchanged after exposure to CO2 at pressures up to 200??bar (1??bar = 105??Pa). Each coal responds differently to the CO2 exposure and this response appears to be different in pores of various sizes within the same coal. For the Seelyville coal at reservoir conditions (16????C, 50??bar), CO2 condenses from a gas into liquid, which leads to increased average fluid density in the pores (??pore) with sizes (r) 1 ?? 105 ??? r ??? 1 ?? 104???? (??pore ??? 0.489??g/cm3) as well as in small pores with size between 30 and 300???? (??pore ??? 0.671??g/cm3). These values are by a factor of three to four higher than the density of bulk CO2 (??CO2) under similar thermodynamic conditions (??CO2 ??? 0.15??g/cm3). At the same time, in the intermediate size pores with r ??? 1000???? the average fluid density is similar to the density of bulk fluid, which indicates that adsorption does not occur in these pores. At in situ conditions for the Baralaba coal (35 OC, 100??bar), the average fluid density of CO2 in all pores is lower than that of the bulk fluid (??pore / ??CO2 ??? 0.6). Neutron scattering from the

  18. Dynamic response of fly ash reinforced functionally graded rubber ...

    African Journals Online (AJOL)

    user

    dimensional vibration analysis of functionally graded material sandwich plates, Journal of. Sound and Vibration, Vol. 311, pp. 498-515. Mahapatra S.S., Chaturvedi V., 2009. Modelling and analysis of abrasive wear performance of composites using ...

  19. Quantifying stochastic resonance in bistable systems: Response vs residence-time distribution functions

    Science.gov (United States)

    Choi, Mee H.; Fox, R. F.; Jung, P.

    1998-06-01

    A wealth of research on stochastic resonance (SR) during the past decade has led to different ways of defining this phenomenon. Most prominent are measures based on the response function and on the residence-time distribution function. While the theory for the response functions is well developed, a first fully systematic theory for the residence-time distribution functions is developed in this paper. Subsequently we reconsider formerly introduced measures of SR based on the residence-time distribution and compare with those based on the response function.

  20. Linear density response function in the projector augmented wave method

    DEFF Research Database (Denmark)

    Yan, Jun; Mortensen, Jens Jørgen; Jacobsen, Karsten Wedel

    2011-01-01

    functions of Si, C, SiC, AlP, and GaAs compare well with previous calculations. While optical properties of semiconductors, in particular excitonic effects, are generally not well described by ALDA, we obtain excellent agreement with experiments for the surface loss function of graphene and the Mg(0001......) surface with plasmon energies deviating by less than 0.2 eV. Finally, the method is applied to study the influence of substrates on the plasmon excitations in graphene....

  1. TOA and AOA Statistics for Distant Circular Scattering Model

    Directory of Open Access Journals (Sweden)

    NIAN Xiaohong

    2012-09-01

    Full Text Available General scattering model is local scattering process assumed that the mobile station is located inside the scattering region, in order to study distant scattering model in suburban or hilly propagation environment, a geometrically based statistical distant circular scattering mode in macrocell environment was proposed, the closed-form expressions of the joint probability density function of the time of arrival /the angle of arrival, the marginal probability density function of the angle of arrival and the angle of departure, the marginal probability density function of the time of arrival were derived, this probability density functions provided insight into the properties of the spatial distant scattering channel model.

  2. On scattered subword complexity

    CERN Document Server

    Kása, Zoltán

    2011-01-01

    Special scattered subwords, in which the gaps are of length from a given set, are defined. The scattered subword complexity, which is the number of such scattered subwords, is computed for rainbow words.

  3. Monte Carlo calculation of the spatial response (Modulated Transfer Function) of a scintillation flat panel and comparison with experimental results

    Science.gov (United States)

    Juste, Belén; Miró, Rafael; Monasor, Paula; Verdú, Gumersindo

    2015-11-01

    Phosphor screens are commonly used in many X-ray imaging applications. The design and optimization of these detectors can be achieved using Monte Carlo codes to simulate radiation transport in scintillation materials and to improve the spatial response. This work presents an exhaustive procedure to measure the spatial resolution of a scintillation flat panel image and to evaluate the agreement with data obtained by simulation. To evaluate the spatial response we have used the Modulated Transfer Function (MTF) parameter. According to this, we have obtained the Line Spread Function (LSF) of the system since the Fourier Transform (FT) of the LSF gives the MTF. The experimental images were carried out using a medical X-ray tube (Toshiba E7299X) and a flat panel (Hammamatsu C9312SK). Measurements were based on the slit methodology experimental implementation, which measures the response of the system to a line. LSF measurements have been performed using a 0.2 mm wide lead slit superimposed over the flat panel. The detector screen was modelled with MCNP (version 6) Monte Carlo simulation code in order to analyze the effect of the acquisition setup configuration and to compare the response of scintillator screens with the experimental results. MCNP6 offers the possibility of studying the optical physics parameters (optical scattering and absorption coefficients) that occur in the phosphor screen. The study has been tested for different X-ray tube voltages, from 100 to 140 kV. An acceptable convergence between the MTF results obtained with MCNP6 and the experimental measurements have been obtained.

  4. Cerebral microvascular network geometry changes in response to functional stimulation.

    Science.gov (United States)

    Lindvere, Liis; Janik, Rafal; Dorr, Adrienne; Chartash, David; Sahota, Bhupinder; Sled, John G; Stefanovic, Bojana

    2013-05-01

    The cortical microvessels are organized in an intricate, hierarchical, three-dimensional network. Superimposed on this anatomical complexity is the highly complicated signaling that drives the focal blood flow adjustments following a rise in the activity of surrounding neurons. The microvascular response to neuronal activation remains incompletely understood. We developed a custom two photon fluorescence microscopy acquisition and analysis to obtain 3D maps of neuronal activation-induced changes in the geometry of the microvascular network of the primary somatosensory cortex of anesthetized rats. An automated, model-based tracking algorithm was employed to reconstruct the 3D microvascular topology and represent it as a graph. The changes in the geometry of this network were then tracked, over time, in the course of electrical stimulation of the contralateral forepaw. Both dilatory and constrictory responses were observed across the network. Early dilatory and late constrictory responses propagated from deeper to more superficial cortical layers while the response of the vertices that showed initial constriction followed by later dilation spread from cortical surface toward increasing cortical depths. Overall, larger caliber adjustments were observed deeper inside the cortex. This work yields the first characterization of the spatiotemporal pattern of geometric changes on the level of the cortical microvascular network as a whole and provides the basis for bottom-up modeling of the hemodynamically-weighted neuroimaging signals. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. A theoretical study on the impact of particle scattering on the channel characteristics of underwater optical communication system

    Science.gov (United States)

    Sahu, Sanjay Kumar; Shanmugam, Palanisamy

    2018-02-01

    Scattering by water molecules and particulate matters determines the path and distance of photon propagation in underwater medium. Consequently, photon angle of scattering (given by scattering phase function) requires to be considered in addition to the extinction coefficient of the aquatic medium governed by the absorption and scattering coefficients in channel characterization for an underwater wireless optical communication (UWOC) system. This study focuses on analyzing the received signal power and impulse response of UWOC channel based on Monte-Carlo simulations for different water types, link distances, link geometries and transceiver parameters. A newly developed scattering phase function (referred to as SS phase function), which represents the real water types more accurately like the Petzold phase function, is considered for quantification of the channel characteristics along with the effects of absorption and scattering coefficients. A comparison between the results simulated using various phase function models and the experimental measurements of Petzold revealed that the SS phase function model predicts values closely matching with the actual values of the Petzold's phase function, which further establishes the importance of using a correct scattering phase function model while estimating the channel capacity of UWOC system in terms of the received power and channel impulse response. Results further demonstrate a great advantage of considering the nonzero probability of receiving scattered photons in estimating channel capacity rather than considering the reception of only ballistic photons as in Beer's Law, which severely underestimates the received power and affects the range of communication especially in the scattering water column. The received power computed based on the Monte-Carlo method by considering the receiver aperture sizes and field of views in different water types are further analyzed and discussed. These results are essential for

  6. Acute pulmonary function response to ozone in young adults as a function of body mass index

    Science.gov (United States)

    Recent studies have shown enhanced responsiveness to ozone in obese mice. Adiposity has not been examined as a possible modulator of ozone response in humans. We therefore examined the relationship between body mass index and the acute spirometric response to ozone (O(3)) exposur...

  7. 32 CFR 352a.4 - Responsibilities and functions.

    Science.gov (United States)

    2010-07-01

    ..., nonappropriated, working capital, revolving, and trust fund activities, including security assistance. (3... ensure their proper relationship with other DoD functional areas (e.g., budget, personnel, logistics... finance and accounting activities independent of the DFAS. (10) Develop, issue, and maintain DoD 7220.9-M...

  8. Organizing the HRM function: Responses to paradoxes, variety and dynamism

    NARCIS (Netherlands)

    Keegan, Anne; Bitterling, Ilja; Sylva, Hella; Hoeksema, L.H.

    2017-01-01

    We develop empirically based insights from five case studies and argue that how actors respond to paradoxical tensions helps to explain variety and dynamism in how the HRM function is organized. It also helps to clarify why widely popular models with clearly prescribed structures take on a variety

  9. Ventilatory functions response to breathing training versus aerobic ...

    African Journals Online (AJOL)

    Background: There is worldwide public interest in physical therapies for asthma. Objective: To compare the effects of a program of breathing training and aerobic training on ventilatory functions in children with bronchial asthma. Methods: Forty asthmatic children from both genders (22 boys and 18 girls) were recruited to ...

  10. Dynamic response of fly ash reinforced functionally graded rubber ...

    African Journals Online (AJOL)

    The dynamic analysis of jute-epoxy sandwiches with fly ash reinforced functionally gradient (FG) flexible, compliant rubber core is presented. FG samples are prepared using conventional casting technique. Presence of gradation is quantified by weight method. An attempt is made to study the influence of fly ash weight ...

  11. Functional MRI of human hypothalamic responses following glucose ingestion

    NARCIS (Netherlands)

    Smeets, P.A.M.; Graaf, C. de; Stafleu, A.; Osch, M.J.P. van; Grond, J. van der

    2005-01-01

    The hypothalamus is intimately involved in the regulation of food intake, integrating multiple neural and hormonal signals. Several hypothalamic nuclei contain glucose-sensitive neurons, which play a crucial role in energy homeostasis. Although a few functional magnetic resonance imaging (fMRI)

  12. First episode schizophrenia: functional MRI findings and treatment response

    NARCIS (Netherlands)

    van Veelen, N.M.J.

    2011-01-01

    The research of this thesis centers on the investigation of first-episode medication-naive and recent onset schizophrenia patients. In part I, functional MRI studies are described, in part II short term treatment effects are compared between ziprasidone and olanzapine. Part I, chapter 2: Differences

  13. [Functional imaging of pain: from the somatic response to emotions].

    Science.gov (United States)

    Laurent, Bernard

    2013-01-01

    Functional brain imaging in subjects experiencing pain (real, observed or imagined) has led to considerable progress in our understanding of the role of the brain andpsyche in pain integration and control, as well as some forms of somatoform pain with no anatomical basis. This research is challenging not only the dichotomy between the soma and psyche, but also the concept of psychosomatic pain.

  14. Adjoint Sensitivity Analysis of Radiative Transfer Equation: Temperature and Gas Mixing Ratio Weighting Functions for Remote Sensing of Scattering Atmospheres in Thermal IR

    Science.gov (United States)

    Ustinov, E.

    1999-01-01

    Sensitivity analysis based on using of the adjoint equation of radiative transfer is applied to the case of atmospheric remote sensing in the thermal spectral region with non-negligeable atmospheric scattering.

  15. Functional responses of North Atlantic fish eggs to increasing temperature

    DEFF Research Database (Denmark)

    Tsoukali, Stavroula; Visser, Andre; MacKenzie, Brian

    2016-01-01

    -days and survival of fish eggs from 32 populations of 17 species in the North Atlantic to different temperatures in order to determine potential consequences of global warming for these species. The response of development time exhibited a similar decreasing trend with respect to temperature across species......Temperature increase associated with global climate change can be expected to directly influence the spawning success of fish species, with implications for abundance and distribution. We conducted a meta-analysis to investigate and compare responses of development time, cumulative degree....... There was an overall decrease, across species, in an index of thermal requirement (cumulative degree-days) for egg development with increasing temperature. Within an empirically derived optimal thermal range for egg survival, the thermal requirement was more variable in species adapted to cold waters compared...

  16. Functional response of predatory thrips to two-spotted spider mite - influence of pesticides

    DEFF Research Database (Denmark)

    Pakyari, Hajar; Enkegaard, Annie

    2013-01-01

    A leaf disc bioassay was used to investigate the effects of abamectin and fenpropathrin on the functional response of an acarophagous thrips, Scolothrips longicornis Priesner, to eggs of Tetranychus urticae Koch at 25 ± 1°C, 60 ± 10% RH, 16:8 h (L:D). The type of the functional response differed ...

  17. Time-dependent current-density-functional theory for the metallic response of solids

    NARCIS (Netherlands)

    Romaniello, P; de Boeij, PL

    We extend the formulation of time-dependent current-density-functional theory for the linear response properties of dielectric and semi-metallic solids [Kootstra , J. Chem. Phys. 112, 6517 (2000)] to treat metals as well. To achieve this, the Kohn-Sham response functions have to include both

  18. Analytical solutions for spin response functions in model storage rings with Siberian Snakes

    Energy Technology Data Exchange (ETDEWEB)

    Mane, S.R. [Convergent Computing Inc., P.O. Box 561, Shoreham, NY 11786 (United States)], E-mail: srmane@optonline.net

    2009-03-01

    I present analytical solutions for the spin response functions for radial field rf dipole spin flippers in models of storage rings with one Siberian Snake or two diametrically opposed orthogonal Siberian Snakes. The solutions can serve as benchmarks tests for computer programs. The spin response functions can be used to calculate the resonance strengths for radial field rf dipole spin flippers in storage rings.

  19. Replacing Faulty Conversational Exchanges for Children with Autism by Establishing a Functionally Equivalent Alternative Response.

    Science.gov (United States)

    Ross, Denise E.

    2002-01-01

    This study used modified functional analysis and functional communication training to assess and replace the faulty communication responses of three older children with autism during conversational exchanges. Results suggested that attention was the maintaining consequence. Correct responses and speaker/listener exchanges during social…

  20. Response and function of skeletal muscle heat shock protein 70.

    Science.gov (United States)

    Liu, Yuefei; Gampert, Larissa; Nething, Katja; Steinacker, Jürgen M

    2006-09-01

    In response to stress, cells produce a series of heat shock proteins (Hsps). One of the most prominent Hsps, is the 70 kDa Hsp (Hsp70). Hsp70 is a highly conserved and essential protein against stress. The skeletal muscle responds to a diverse group of stress signals namely, muscle contraction linked energy and milieu challenges, ischemia and exercise by producing Hsp70. The extent of this Hsp70 response in skeletal muscle depends on the type and intensity of the signal, and is characterized in a muscle fiber specific manner by a special time course. Hsp70 in the skeletal muscle is regulated at transcriptional, translational and posttranslational levels. Hsp70 serves as an indicator for cellular stress as a molecular chaperone, plays pivotal role in maintaining cellular homeostasis by preventing apoptosis, influences energy metabolism, facilitates cellular processes in terms of muscular adaptation and interacts with other signalling pathways. This review summarizes our current knowledge on the skeletal muscle Hsp70 response.

  1. Function plot response: A scalable system for teaching kinematics graphs

    Science.gov (United States)

    Laverty, James; Kortemeyer, Gerd

    2012-08-01

    Understanding and interpreting graphs are essential skills in all sciences. While students are mostly proficient in plotting given functions and reading values off graphs, they frequently lack the ability to construct and interpret graphs in a meaningful way. Students can use graphs as representations of value pairs, but often fail to interpret them as the representation of functions, and mostly fail to use them as representations of physical reality. Working with graphs in classroom settings has been shown to improve student abilities with graphs, particularly when the students can interact with them. We introduce a novel problem type in an online homework system, which requires students to construct the graphs themselves in free form, and requires no hand-grading by instructors. Initial experiences using the new problem type in an introductory physics course are reported.

  2. Ag Nanoparticle-Functionalized Open-Ended Freestanding TiO₂ Nanotube Arrays with a Scattering Layer for Improved Energy Conversion Efficiency in Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Rho, Won-Yeop; Chun, Myeung-Hwan; Kim, Ho-Sub; Kim, Hyung-Mo; Suh, Jung Sang; Jun, Bong-Hyun

    2016-06-15

    Dye-sensitized solar cells (DSSCs) were fabricated using open-ended freestanding TiO₂ nanotube arrays functionalized with Ag nanoparticles (NPs) in the channel to create a plasmonic effect, and then coated with large TiO₂ NPs to create a scattering effect in order to improve energy conversion efficiency. Compared to closed-ended freestanding TiO₂ nanotube array-based DSSCs without Ag or large TiO₂ NPs, the energy conversion efficiency of closed-ended DSSCs improved by 9.21% (actual efficiency, from 5.86% to 6.40%) with Ag NPs, 6.48% (actual efficiency, from 5.86% to 6.24%) with TiO₂ NPs, and 14.50% (actual efficiency, from 5.86% to 6.71%) with both Ag NPs and TiO₂ NPs. By introducing Ag NPs and/or large TiO₂ NPs to open-ended freestanding TiO₂ nanotube array-based DSSCs, the energy conversion efficiency was improved by 9.15% (actual efficiency, from 6.12% to 6.68%) with Ag NPs and 8.17% (actual efficiency, from 6.12% to 6.62%) with TiO₂ NPs, and by 15.20% (actual efficiency, from 6.12% to 7.05%) with both Ag NPs and TiO₂ NPs. Moreover, compared to closed-ended freestanding TiO₂ nanotube arrays, the energy conversion efficiency of open-ended freestanding TiO₂ nanotube arrays increased from 6.71% to 7.05%. We demonstrate that each component-Ag NPs, TiO₂ NPs, and open-ended freestanding TiO₂ nanotube arrays-enhanced the energy conversion efficiency, and the use of a combination of all components in DSSCs resulted in the highest energy conversion efficiency.

  3. New Insight into the Local Structure of Hydrous Ferric Arsenate Using Full-Potential Multiple Scattering Analysis, Density Functional Theory Calculations, and Vibrational Spectroscopy.

    Science.gov (United States)

    Wang, Shaofeng; Ma, Xu; Zhang, Guoqing; Jia, Yongfeng; Hatada, Keisuke

    2016-11-15

    Hydrous ferric arsenate (HFA) is an important arsenic-bearing precipitate in the mining-impacted environment and hydrometallurgical tailings. However, there is no agreement on its local atomic structure. The local structure of HFA was reprobed by employing a full-potential multiple scattering (FPMS) analysis, density functional theory (DFT) calculations, and vibrational spectroscopy. The FPMS simulations indicated that the coordination number of the As-Fe, Fe-As, or both in HFA was approximately two. The DFT calculations constructed a structure of HFA with the formula of Fe(HAsO4)x(H2AsO4)1-x(OH)y·zH2O. The presence of protonated arsenate in HFA was also evidenced by vibrational spectroscopy. The As and Fe K-edge X-ray absorption near-edge structure spectra of HFA were accurately reproduced by FPMS simulations using the chain structure, which was also a reasonable model for extended X-Ray absorption fine structure fitting. The FPMS refinements indicated that the interatomic Fe-Fe distance was approximately 5.2 Å, consistent with that obtained by Mikutta et al. (Environ. Sci. Technol. 2013, 47 (7), 3122-3131) using wavelet analysis. All of the results suggested that HFA was more likely to occur as a chain with AsO4 tetrahedra and FeO6 octahedra connecting alternately in an isolated bidentate-type fashion. This finding is of significance for understanding the fate of arsenic and the formation of ferric arsenate minerals in an acidic environment.

  4. Multi-timescale measurements of brain responses in visual cortex during functional stimulation using time-resolved spectroscopy

    Science.gov (United States)

    Lebid, Solomiya; O'Neill, Raymond; Markham, Charles; Ward, Tomás; Coyle, Shirley

    2005-06-01

    Studies of neurovascular coupling (hemodynamic changes and neuronal activation) in the visual cortex using a time-domain single photon counting system have been undertaken. The system operates in near infrared (NIR) range of spectrum and allows functional brain monitoring to be done non-invasively. The detection system employs a photomultiplier and multi-channel scaler to detect and record emerging photons with sub-microsecond resolution (the effective collection time per curve point is ~ 200 ns). Localisation of the visual evoked potentials in the brain was done using knowledge obtained from electroencephalographic (EEG) studies and previous frequency-domain optical NIR spectroscopic systems. The well-known approach of visual stimulation of the human brain, which consists of an alternating black and white checkerboard pattern used previously for the EEG study of neural responses, is applied here. The checkerboard pattern is synchronized with the multi-channel scaler system and allows the analysis of time variation in back-scattered light, at different stimulation frequencies. Slow hemodynamic changes in the human brain due to Hb-HbO2 changes in the blood flow were observed, which is evidence of the system's capability to monitor these changes. Monocular visual tests were undertaken and compared with those done with an EEG system. In some subjects a fast optical response on a time scale commensurate with the neural activity associated with the visual cortex was detected. Future work will concentrate on improved experimental protocols and apparatus to confirm the existence of this important physiological signal.

  5. Functional changes in littoral macroinvertebrate communities in response to watershed-level anthropogenic stress.

    Directory of Open Access Journals (Sweden)

    Katya E Kovalenko

    Full Text Available Watershed-scale anthropogenic stressors have profound effects on aquatic communities. Although several functional traits of stream macroinvertebrates change predictably in response to land development and urbanization, little is known about macroinvertebrate functional responses in lakes. We assessed functional community structure, functional diversity (Rao's quadratic entropy and voltinism in macroinvertebrate communities sampled across the full gradient of anthropogenic stress in Laurentian Great Lakes coastal wetlands. Functional diversity and voltinism significantly decreased with increasing development, whereas agriculture had smaller or non-significant effects. Functional community structure was affected by watershed-scale development, as demonstrated by an ordination analysis followed by regression. Because functional community structure affects energy flow and ecosystem function, and functional diversity is known to have important implications for ecosystem resilience to further environmental change, these results highlight the necessity of finding ways to remediate or at least ameliorate these effects.

  6. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  7. Monitoring asthma in childhood: lung function, bronchial responsiveness and inflammation.

    Science.gov (United States)

    Moeller, Alexander; Carlsen, Kai-Hakon; Sly, Peter D; Baraldi, Eugenio; Piacentini, Giorgio; Pavord, Ian; Lex, Christiane; Saglani, Sejal

    2015-06-01

    This review focuses on the methods available for measuring reversible airways obstruction, bronchial hyperresponsiveness (BHR) and inflammation as hallmarks of asthma, and their role in monitoring children with asthma. Persistent bronchial obstruction may occur in asymptomatic children and is considered a risk factor for severe asthma episodes and is associated with poor asthma outcome. Annual measurement of forced expiratory volume in 1 s using office based spirometry is considered useful. Other lung function measurements including the assessment of BHR may be reserved for children with possible exercise limitations, poor symptom perception and those not responding to their current treatment or with atypical asthma symptoms, and performed on a higher specialty level. To date, for most methods of measuring lung function there are no proper randomised controlled or large longitudinal studies available to establish their role in asthma management in children. Noninvasive biomarkers for monitoring inflammation in children are available, for example the measurement of exhaled nitric oxide fraction, and the assessment of induced sputum cytology or inflammatory mediators in the exhaled breath condensate. However, their role and usefulness in routine clinical practice to monitor and guide therapy remains unclear, and therefore, their use should be reserved for selected cases. Copyright ©ERS 2015.

  8. Separated Response Function Ratios in Exclusive, Forward pi^{+/-} Electroproduction

    CERN Document Server

    Huber, G M; Butuceanu, C; Gaskell, D; Horn, T; Mack, D J; Abbott, D; Aniol, K; Anklin, H; Armstrong, C; Arrington, J; Assamagan, K; Avery, S; Baker, O K; Barrett, B; Beise, E J; Bochna, C; Boeglin, W; Brash, E J; Breuer, H; Chang, C C; Chant, N; Christy, M E; Dunne, J; Eden, T; Ent, R; Fenker, H; Gibson, E F; Gilman, R; Gustafsson, K; Hinton, W; Holt, R J; Jackson, H; Jin, S; Jones, M K; Keppel, C E; Kim, P H; Kim, W; King, P M; Klein, A; Koltenuk, D; Kovaltchouk, V; Liang, M; Liu, J; Lolos, G J; Lung, A; Margaziotis, D J; Markowitz, P; Matsumura, A; McKee, D; Meekins, D; Mitchell, J; Miyoshi, T; Mkrtchyan, H; Mueller, B; Niculescu, G; Niculescu, I; Okayasu, Y; Pentchev, L; Perdrisat, C; Pitz, D; Potterveld, D; Punjabi, V; Qin, L M; Reimer, P E; Reinhold, J; Roche, J; Roos, P G; Sarty, A; Shin, I K; Smith, G R; Stepanyan, S; Tang, L G; Tadevosyan, V; Tvaskis, V; van der Meer, R L J; Vansyoc, K; Van Westrum, D; Vidakovic, S; Volmer, J; Vulcan, W; Warren, G; Wood, S A; Xu, C; Yan, C; Zhao, W -X; Zheng, X; Zihlmann, B

    2014-01-01

    The study of exclusive $\\pi^{\\pm}$ electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio $R_L=\\sigma_L^{\\pi^-}/\\sigma_L^{\\pi^+}$ is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of $R_T=\\sigma_T^{\\pi^-}/\\sigma_T^{\\pi^+}$ from unity at small $-t$, to 1/4 at large $-t$, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Furthermore, the mentioned ratios may show an earlier approach to pQCD than the individual cross sections. We have performed the first complete separation of the four unpolarized electromagnetic structure functions above the dominant resonances in forward, exclusive $\\pi^{\\pm}$ electroproduction on the deuteron at central $Q^2$ values of 0.6, 1.0, 1.6 GeV$^2$ at $W$=1.95 GeV, and $Q^2=2.45$ GeV$^2$ at $W...

  9. Monitoring asthma in childhood: lung function, bronchial responsiveness and inflammation

    Directory of Open Access Journals (Sweden)

    Alexander Moeller

    2015-06-01

    Full Text Available This review focuses on the methods available for measuring reversible airways obstruction, bronchial hyperresponsiveness (BHR and inflammation as hallmarks of asthma, and their role in monitoring children with asthma. Persistent bronchial obstruction may occur in asymptomatic children and is considered a risk factor for severe asthma episodes and is associated with poor asthma outcome. Annual measurement of forced expiratory volume in 1 s using office based spirometry is considered useful. Other lung function measurements including the assessment of BHR may be reserved for children with possible exercise limitations, poor symptom perception and those not responding to their current treatment or with atypical asthma symptoms, and performed on a higher specialty level. To date, for most methods of measuring lung function there are no proper randomised controlled or large longitudinal studies available to establish their role in asthma management in children. Noninvasive biomarkers for monitoring inflammation in children are available, for example the measurement of exhaled nitric oxide fraction, and the assessment of induced sputum cytology or inflammatory mediators in the exhaled breath condensate. However, their role and usefulness in routine clinical practice to monitor and guide therapy remains unclear, and therefore, their use should be reserved for selected cases.

  10. Covalent bonding from alchemical linear response density functional theory

    CERN Document Server

    Chang, K Y Samuel; Ramakrishnan, Raghunathan; von Lilienfeld, O Anatole

    2015-01-01

    We assess the predictive accuracy of linear response based estimates of changes in covalent bonding due to linear alchemical interpolations among molecules. We have investigated single bonds to hydrogen, as well as single, double, and triple bonds between main-group elements, occurring in small iso-electronic molecular spaces with atomic elements drawn from rows 2-3 in the $p$-block of the periodic table. Numerical evidence suggests that first order estimates of bonding potentials can achieve chemical accuracy if the alchemical interpolation connects molecules containing late elements in the periodic table (3$^{rd}$ and 4$^{th}$ row) and identical number of atoms and molecular geometries. For these interpolations, changes in bonding potential are near-linear in the coupling parameter, resulting in accurate Hellmann-Feynman predictions. Second order estimates for such interpolations yield worse predictions. The predictions become substantially worse if initial and final molecules differ not only in composition...

  11. Contamination Forecast in Liquid Residues by Response Functions

    Directory of Open Access Journals (Sweden)

    Elizabeth Canchingre−Bone

    2016-12-01

    Full Text Available In objective 11 of the National Plan for Good Living (2013-2017, the state considers water as a strategic sector, a renewable natural resource; however, industries have excluded from the productive process the rational planning of pollution of Residuals Liquids. The level of efficiency of the planned in these residues in the Esmeraldas Refinery is insufficient, since it is not known from the factory point of view what is the factor that most affects the contamination, with the aim of emphasizing its decrease, Which leads to the use of econometric techniques to achieve this objective. For its fulfillment a Multiple Linear Regression model is used, from five functions to choose the best one. The results have enabled the Esmeraldas State Refinery to create the necessary premises for the execution of the 2018-2020 investment plan with the minimum cost and recovery period.

  12. Response and correlation functions of nonlinear systems in equilibrium states

    Science.gov (United States)

    Xu, Lubo; Wang, Lei

    2017-11-01

    In this paper, we study systematically a serial of correlation functions in some one-dimensional nonlinear lattices. Due to the energy conservation law, they are implicitly interdependent. Various transport coefficients are thus also connected. In the studies of the autocorrelations of local energy density and of local heat current, a general relation between diverging heat conduction and super heat diffusion has been proposed recently. We clarify that such a relation is valid only in systems without temperature pressure. In those with temperature pressure, a constant but nontrivial term appears. This term explains a previously observed fact that heat diffusion in such systems is always ballistic but heat conduction can diverge very slowly. Such a result not only disproves the existence of any general relation between diverging heat conduction and super heat diffusion, but it also breaks the long-term presumption that ballistic heat conduction and diffusion always coexist.

  13. Whole-word response scoring underestimates functional spelling ability for some individuals with global agraphia

    OpenAIRE

    Andrew Tesla Demarco

    2015-01-01

    Introduction Assessment of spelling deficits in aphasia typically follows the convention that responses are scored as either correct or incorrect, with some coding of error type. In some instances, the response may be quite close to the target (e.g., circiut for circuit), while in other cases the response bears little resemblance (e.g., tricenn for circuit). Responses that resemble the target may have functional value in that they can be deciphered by a communication partner when used in c...

  14. Mechanotransduction and the functional response of bone to mechanical strain

    Science.gov (United States)

    Duncan, R. L.; Turner, C. H.

    1995-01-01

    Mechanotransduction plays a crucial role in the physiology of many tissues including bone. Mechanical loading can inhibit bone resorption and increase bone formation in vivo. In bone, the process of mechanotransduction can be divided into four distinct steps: (1) mechanocoupling, (2) biochemical coupling, (3) transmission of signal, and (4) effector cell response. In mechanocoupling, mechanical loads in vivo cause deformations in bone that stretch bone cells within and lining the bone matrix and create fluid movement within the canaliculae of bone. Dynamic loading, which is associated with extracellular fluid flow and the creation of streaming potentials within bone, is most effective for stimulating new bone formation in vivo. Bone cells in vitro are stimulated to produce second messengers when exposed to fluid flow or mechanical stretch. In biochemical coupling, the possible mechanisms for the coupling of cell-level mechanical signals into intracellular biochemical signals include force transduction through the integrin-cytoskeleton-nuclear matrix structure, stretch-activated cation channels within the cell membrane, G protein-dependent pathways, and linkage between the cytoskeleton and the phospholipase C or phospholipase A pathways. The tight interaction of each of these pathways would suggest that the entire cell is a mechanosensor and there are many different pathways available for the transduction of a mechanical signal. In the transmission of signal, osteoblasts, osteocytes, and bone lining cells may act as sensors of mechanical signals and may communicate the signal through cell processes connected by gap junctions. These cells also produce paracrine factors that may signal osteoprogenitors to differentiate into osteoblasts and attach to the bone surface. Insulin-like growth factors and prostaglandins are possible candidates for intermediaries in signal transduction. In the effector cell response, the effects of mechanical loading are dependent upon the

  15. Scattered light characterization of FORTIS

    Science.gov (United States)

    McCandliss, Stephan R.; Carter, Anna; Redwine, Keith; Teste, Stephane; Pelton, Russell; Hagopian, John; Kutyrev, Alexander; Li, Mary J.; Moseley, S. Harvey

    2017-08-01

    We describe our efforts to build a Wide-Field Lyman alpha Geocoronal simulator (WFLaGs) for characterizing the end-to-end sensitivity of FORTIS (Far-UV Off Rowland-circle Telescope for Imaging and Spectroscopy) to scattered Lyman α emission from outside of the nominal (1/2 degree)2 field-of-view. WFLaGs is a 50 mm diameter F/1 aluminum parabolic collimator fed by a hollow cathode discharge lamp with a 80 mm clear MgF2 window housed in a vacuum skin. It creates emission over a 10 degree FOV. WFLaGS will allow us to validate and refine a recently developed scattered light model and verify our scatter light mitigation strategies, which will incorporate low scatter baffle materials, and possibly 3-d printed light traps, covering exposed scatter centers. We present measurements of scattering intensity of Lyman alpha as a function of angle with respect to the specular reflectance direction for several candidate baffle materials. Initial testing of WFLaGs will be described.

  16. Dispersion Relations in Scattering and Antenna Problems

    OpenAIRE

    Sohl, Christian

    2008-01-01

    This dissertation deals with physical bounds on scattering and absorption of acoustic and electromagnetic waves. A general dispersion relation or sum rule for the extinction cross section of such waves is derived from the holomorphic properties of the scattering amplitude in the forward direction. The derivation is based on the forward scattering theorem via certain Herglotz functions and their asymptotic expansions in the low-frequency and high-frequency regimes. The result states that, for ...

  17. Hierarchy in chaotic scattering in Hill's problem

    CERN Document Server

    Kovács, Z

    1997-01-01

    Hierarchic properties of chaotic scattering in a model of satellite encounters, studied first by Petit and Henon, are examined by decomposing the dwell time function and comparing scattering trajectories. The analysis reveals an (approximate) ternary organization in the chaotic set of bounded orbits and the presence of a stable island. The results can open the way for a calculation of global quantities characterizing the scattering process by using tools of the thermodynamic formalism.

  18. Calibration of the time response functions of a quenched plastic scintillator for neutron time of flight

    CERN Document Server

    Chen, J B; Peng, H S; Tang, C H; Zhang, B H; Ding, Y K; Chen, M; Chen, H S; Li, C G; Wen, T S; Yu, R Z

    2002-01-01

    The time response functions of an ultrafast quenched plastic scintillation detector used to measure neutron time of flight spectra were calibrated by utilizing cosmic rays and implosion neutrons from DT-filled capsules at the Shenguang II laser facility. These sources could be regarded as delta function pulses due to their much narrower time widths than those of the time response functions of the detection system. The results showed that the detector responses to DT neutrons and to cosmic rays were 1.18 and 0.96 ns FWHM, respectively.

  19. The flexibility of low molecular weight double-stranded DNA as a function of length. I. Light scattering measurements and the estimation of persistence lengths from light scattering, sedimentation and viscosity.

    Science.gov (United States)

    Godfrey, J E; Eisenberg, H

    1976-09-01

    In the preceding paper are described the isolation and physical characterization of seven narrowly disperse fractions of calf thymus DNA in the molecular weight range 0.3 to 1.3 X 10(6) daltons. Herein, we have determined by light scattering the molecular weights and root mean square radii of these fractions in a solvent comprising 0.2 M NaCl, 2 mM EDTA, 2mM Na-PO4,pH7. Measurements were made in a modified Wippler-Scheibling photometer to a 20 degree lower limit of scattering angle on solutions rendered virtually dust-free by procedures described. The optical anisotropies of the DNA fractions were measured permitting the experimental molecular weights and root mean square radii to be corrected to their true values. From these values, with appropriate polydispersity corrections, we calculate a Kratky-Porod persistence length, a, of 54.0 +/- 5.6 nm which is invariant over the molecular range examined. From the sedimentation coefficients (preceding paper) and the theory of Yamakawa and Fujii, we calculate a to be 66 nm, a value found to apply equally well to several DNA samples of various origins whose sedimentation rates are known in themolecular weight range from about 4 X 10(4) to 10(8) daltons. Similarly, from the intrinsic viscosities and the theory of Yamakawa and Fujii, we calculate a to be 59 nm, which again adequately applies to a number of DNA samples whose viscosities have been measured by other workers in the molecular wieght range 3 X 10(5) to 10(8) daltons. The Flory-Mandelkern paramerter, beta, was found to vary with molecular weight in the manner predicted by the theory of Yamakawa and Fujii. The average value of a from the three sets of measurements is 60 +/- 6nm, which we believe applies to double-stranded DNA molecules, independent of chain length, over the whole range of molecular weights from which reliable data exist.

  20. Elliptic scattering equations

    Energy Technology Data Exchange (ETDEWEB)

    Cardona, Carlos [Physics Division, National Center for Theoretical Sciences, National Tsing-Hua University,Hsinchu, Taiwan 30013 (China); Gomez, Humberto [Instituto de Fisica - Universidade de São Paulo,Caixa Postal 66318, 05315-970 São Paulo, SP (Brazil); Facultad de Ciencias Basicas, Universidad Santiago de Cali,Calle 5 62-00 Barrio Pampalinda, Cali, Valle (Colombia)

    2016-06-16

    Recently the CHY approach has been extended to one loop level using elliptic functions and modular forms over a Jacobian variety. Due to the difficulty in manipulating these kind of functions, we propose an alternative prescription that is totally algebraic. This new proposal is based on an elliptic algebraic curve embedded in a ℂP{sup 2} space. We show that for the simplest integrand, namely the n−gon, our proposal indeed reproduces the expected result. By using the recently formulated Λ−algorithm, we found a novel recurrence relation expansion in terms of tree level off-shell amplitudes. Our results connect nicely with recent results on the one-loop formulation of the scattering equations. In addition, this new proposal can be easily stretched out to hyperelliptic curves in order to compute higher genus.

  1. Estimated Quality of Multistage Process on the Basis of Probabilistic Approach with Continuous Response Functions

    Directory of Open Access Journals (Sweden)

    Yuri B. Tebekin

    2011-11-01

    Full Text Available The article is devoted to the problem of the quality management for multiphase processes on the basis of the probabilistic approach. Method with continuous response functions is offered from the application of the method of Lagrange multipliers.

  2. Stimulus-responsive polymers and other functional polymer surfaces as components in glass microfluidic channels

    NARCIS (Netherlands)

    Kieviet, B.D.; Schön, Peter Manfred; Vancso, Gyula J.

    2014-01-01

    The integration of smart stimulus-responsive polymers as functional elements within microfluidic devices has greatly improved the performance capabilities of controlled fluid delivery. For their use as actuators in microfluidic systems, reversible expansion and shrinking are unique mechanisms which

  3. Alpine plant functional group responses to fertiliser addition depend on abiotic regime and community composition.

    NARCIS (Netherlands)

    Onipchenko, V.G.; Makarov, M.I.; Akmetzhanova, A.A.; Soudzilovskaia, N.A.; Aibazova, F.U.; Elkanova, M.K.; Stogova, A.V.; Cornelissen, J.H.C.

    2012-01-01

    Background and aims: We ask how productivity responses of alpine plant communities to increased nutrient availability can be predicted from abiotic regime and initial functional type composition. Methods: We compared four Caucasian alpine plant communities (lichen heath, Festuca varia grassland,

  4. Field measurements give biased estimates of functional response parameters, but help explain foraging distributions

    NARCIS (Netherlands)

    Duijns, S.; Knot, I.E.; Piersma, T.; van Gils, J.A.

    2015-01-01

    1.Mechanistic insights and predictive understanding of the spatial distributions of foragers are typically derived by fitting either field measurements on intake rates and food abundance, or observations from controlled experiments, to functional response models. It has remained unclear, however,

  5. Impulse-response function of splanchnic circulation with model-independent constraints: theory and experimental validation

    DEFF Research Database (Denmark)

    Munk, O L; Keiding, S; Bass, L

    2003-01-01

    from constraining the regression fits by parameters estimated independently. This is strong evidence for the physiological relevance of the impulse-response function, which includes asymptotically, and thereby justifies kinetically, a useful and simple power law. Similarity between our parameter...

  6. Periodic solutions for a food chain system with Monod-Haldane functional response on time scales

    Directory of Open Access Journals (Sweden)

    Kejun Zhuang

    2014-02-01

    Full Text Available In this article, we study a three species food chain model on time scales, with Monod-Haldane functional response and time delay. With the help of coincidence degree theory, we establish the existence of periodic solutions.

  7. Li-ion conduction in the LiBH4:LiI system from Density Functional Theory calculations and Quasi-Elastic Neutron Scattering

    DEFF Research Database (Denmark)

    Myrdal, Jon Steinar Gardarsson; Blanchard, Didier; Sveinbjörnsson, Dadi Þorsteinn

    2013-01-01

    to quasi-elastic neutron scattering (QENS) measurements with and without an applied bias potential of 3 V. DFT calculations show that lithium defects such as Frenkel pairs are easily formed at room temperature (formation energy of 0.44 eV) and low energy barriers (0.2 to 0.3 eV) are found between stable...

  8. Herbicide and fertilizers promote analogous phylogenetic responses but opposite functional responses in plant communities

    DEFF Research Database (Denmark)

    Pellissier, Loïc; Wisz, Mary S.; Strandberg, Beate

    2014-01-01

    Throughout the world, herbicides and fertilizers change species composition in agricultural communities, but how do the cumulative effects of these chemicals impact the functional and phylogenetic structure of non-targeted communities when they drift into adjacent semi-natural habitats? Based...... on long-term experiment we show that fertilizer and herbicides (glyphosate) have contrasting effects on functional structure, but can increase phylogenetic diversity in semi-natural plant communities. We found that an increase in nitrogen promoted an increase in the average specific leaf area and canopy...... height at the community level, but an increase in glyphosate promoted a decrease in those traits. Phylogenetic diversity of plant communities increased when herbicide and fertilizer were applied together, likely because functional traits facilitating plant success in those conditions were...

  9. Coupling between minimum scattering antennas

    DEFF Research Database (Denmark)

    Andersen, J.; Lessow, H; Schjær-Jacobsen, Hans

    1974-01-01

    Coupling between minimum scattering antennas (MSA's) is investigated by the coupling theory developed by Wasylkiwskyj and Kahn. Only rotationally symmetric power patterns are considered, and graphs of relative mutual impedance are presented as a function of distance and pattern parameters. Crossed......-dipoles and helices are considered in order to establish a correspondence with simple antenna structures....

  10. Functional Response of Eretmocerus delhiensis on Trialeurodes vaporariorum by Parasitism and Host Feeding

    OpenAIRE

    Ebrahimifar, Jafar; Jamshidnia, Arsalan; Allahyari, Hossein

    2017-01-01

    The parasitoid wasp, Eretmocerus delhiensis (Hymenoptera, Aphelinidae) is a thelytokous and syn-ovigenic parasitoid. To evaluate E. delhiensis as a biocontrol agent in greenhouse, the killing efficiency of this parasitoid by parasitism and host-feeding, were studied. Killing efficiency can be compared by estimation of functional response parameters. Laboratory experiments were performed in controllable conditions to evaluate the functional response of E. delhiensis at eight densities (2, 4, 8...

  11. Cooperative scattering of scalar waves by optimized configurations of point scatterers

    Science.gov (United States)

    Schäfer, Frank; Eckert, Felix; Wellens, Thomas

    2017-12-01

    We investigate multiple scattering of scalar waves by an ensemble of N resonant point scatterers in three dimensions. For up to N = 21 scatterers, we numerically optimize the positions of the individual scatterers, to maximize the total scattering cross section for an incoming plane wave, on the one hand, and to minimize the decay rate associated to a long-lived scattering resonance, on the other. In both cases, the optimum is achieved by configurations where all scatterers are placed on a line parallel to the direction of the incoming plane wave. The associated maximal scattering cross section increases quadratically with the number of scatterers for large N, whereas the minimal decay rate—which is realized by configurations that are not the same as those that maximize the scattering cross section—decreases exponentially as a function of N. Finally, we also analyze the stability of our optimized configurations with respect to small random displacements of the scatterers. These results demonstrate that optimized configurations of scatterers bear a considerable potential for applications such as quantum memories or mirrors consisting of only a few atoms.

  12. Hadron scattering and resonances in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Dudek, Jozef J. [Old Dominion Univ., Norfolk, VA (United States)

    2016-05-01

    I describe how hadron-hadron scattering amplitudes are related to the eigenstates of QCD in a finite cubic volume. The discrete spectrum of such eigenstates can be determined from correlation functions computed using lattice QCD, and the corresponding scattering amplitudes extracted. I review results from the Hadron Spectrum Collaboration who have used these finite volume methods to study pi pi elastic scattering, including the rho resonance, as well as coupled-channel pi K, eta K scattering. Ongoing calculations are advertised and the outlook for finite volume approaches is presented.

  13. A new SERS: scattering enhanced Raman scattering

    Science.gov (United States)

    Bixler, Joel N.; Yakovlev, Vladislav V.

    2014-03-01

    Raman spectroscopy is a powerful technique that can be used to obtain detailed chemical information about a system without the need for chemical markers. It has been widely used for a variety of applications such as cancer diagnosis and material characterization. However, Raman scattering is a highly inefficient process, where only one in 1011 scattered photons carry the needed information. Several methods have been developed to enhance this inherently weak effect, including surface enhanced Raman scattering and coherent anti-Stokes Raman scattering. These techniques suffer from drawbacks limiting their commercial use, such as the need for spatial localization of target molecules to a `hot spot', or the need for complex laser systems. Here, we present a simple instrument to enhance spontaneous Raman scattering using elastic light scattering. Elastic scattering is used to substantially increase the interaction volume. Provided that the scattering medium exhibits very low absorption in the spectral range of interest, a large enhancement factor can be attained in a simple and inexpensive setting. In our experiments, we demonstrate an enhancement of 107 in Raman signal intensity. The proposed novel device is equally applicable for analyzing solids, liquids, and gases.

  14. Endogenous Opioid Function Mediates the Association Between Laboratory Evoked Pain Sensitivity and Morphine Analgesic Responses

    Science.gov (United States)

    Bruehl, Stephen; Burns, John W.; Gupta, Rajnish; Buvanendran, Asokumar; Chont, Melissa; Kinner, Ellen; Schuster, Erik; Passik, Steven; France, Christopher R.

    2014-01-01

    Predictors of responsiveness to opioid analgesic medications are not well understood. This study tested whether individual differences in endogenous opioid (EO) function are associated with analgesic responsiveness to morphine. In randomized, counterbalanced order over three sessions, 45 chronic low back pain participants (CLBP) and 31 healthy controls received an opioid antagonist (8mg naloxone), morphine (0.08 mg/kg), or placebo. Participants then engaged in two laboratory evoked pain tasks (ischemic, thermal). Outcomes included pain threshold, pain tolerance, and pain ratings. Indexes of EO function and morphine analgesic responsiveness were derived for each measure as the difference in pain responses between the placebo condition, and naloxone or morphine conditions respectively. For all 7 pain measures across the two laboratory pain tasks, greater EO function was associated with significantly lower morphine analgesic responsiveness (p ≤ .001 − p=.02). Morphine reduced pain responses of low EO individuals to levels similar to high EO individuals under placebo. Higher placebo condition evoked pain sensitivity was associated with significantly greater morphine analgesic responsiveness for 5 of 7 pain measures (p<.001 − p=.02). These latter associations were significantly mediated by EO function for 4 of these 5 pain outcomes (p’s<.05). In the laboratory evoked pain context, opioid analgesic medications may supplement inadequate EO analgesia, with little incremental benefit in those with pre-existing high EO function. Implications for personalized medicine are discussed. PMID:23748117

  15. Quantifying the functional responses of vegetation to drought and oxygen stress in temperate ecosystems.

    NARCIS (Netherlands)

    Douma, J.C.; Bardin, V.; Bartholomeus, R.P.; van Bodegom, P.M.

    2012-01-01

    Our understanding of the generality of plant functional responses to water availability is limited; current field studies use either very rough approximations of water and oxygen availability or only focus on water-stressed ecosystems. Studies that relate species' responses to a surplus of water are

  16. Quantifying the functional responses of vegetation to drought and oxygen stress in temperate ecosystems

    NARCIS (Netherlands)

    Douma, J.C.; Bardin, V.; Bartholomeus, R.P.; Bodegom, van P.M.

    2012-01-01

    1. Our understanding of the generality of plant functional responses to water availability is limited; current field studies use either very rough approximations of water and oxygen availability or only focus on water-stressed ecosystems. Studies that relate species' responses to a surplus of water

  17. A Method for Investigating the Intersection of Item Response Functions in Mokken's Nonparametric IRT Model.

    Science.gov (United States)

    Sijtsma, Klaas; Meijer, Rob R.

    1992-01-01

    A method is proposed for investigating the intersection of item response functions in the nonparametric item-response-theory model of R. J. Mokken (1971). Results from a Monte Carlo study support the proposed use of the transposed data matrix H(sup T) as an extension to Mokken's approach. (SLD)

  18. The Person Response Function as a Tool in Person-Fit Research.

    Science.gov (United States)

    Sijtsma, Klaas; Meijer, Rob R.

    2001-01-01

    Studied the use of the person response function (PRF) for identifying nonfitting item score patterns. Proposed a person-fit method reformulated in a nonparametric item response theory (IRT) context. Conducted a simulation study to compare the use of the PRF with a person-fit statistic, resulting in the conclusion that the PRF can be used as a…

  19. Data Equivalency of an Interactive Voice Response System for Home Assessment of Back Pain and Function

    Directory of Open Access Journals (Sweden)

    William S Shaw

    2007-01-01

    Full Text Available BACKGROUND: Interactive voice response (IVR systems that collect survey data using automated, push-button telephone responses may be useful to monitor patients’ pain and function at home; however, its equivalency to other data collection methods has not been studied.

  20. Exposure-response functions for (or versus?) the prediction of annoyance in specific situations

    NARCIS (Netherlands)

    Janssen, S.A.; Vos, H.

    2012-01-01

    Based on data from many surveys, exposure-response functions have been derived to describe the average expected annoyance response at a certain noise level. These have been used to define acceptable levels of environmental noise for separate noise sources. However, the prediction of the annoyance

  1. Pili-like proteins of Akkermansia muciniphila modulate host immune responses and gut barrier function

    NARCIS (Netherlands)

    Ottman, N.; Reunanen, J.; Meijerink, M.; Pietila, T.E.; Kainulainen, V.; Klievink, J.; Huuskonen, L.; Aalvink, S.; Skurnik, M.; Boeren, S.; Satokari, R.; Mercenier, A.; Palva, A.; Smidt, H.; Vos, W.M. De; Belzer, C.

    2017-01-01

    Gut barrier function is key in maintaining a balanced response between the host and its microbiome. The microbiota can modulate changes in gut barrier as well as metabolic and inflammatory responses. This highly complex system involves numerous microbiota-derived factors. The gut symbiont

  2. Pili-like proteins of Akkermansia muciniphila modulate host immune responses and gut barrier function

    NARCIS (Netherlands)

    Ottman, Noora; Reunanen, Justus; Meijerink, Marjolein; Pietila, Taija E.; Kainulainen, Veera; Klievink, Judith; Huuskonen, Laura; Aalvink, Steven; Skurnik, Mikael; Boeren, Sjef; Satokari, Reetta; Mercenier, Annick; Palva, Airi; Smidt, Hauke; Vos, de Willem M.; Belzer, Clara

    2017-01-01

    Gut barrier function is key in maintaining a balanced response between the host and its microbiome. The microbiota can modulate changes in gut barrier as well as metabolic and inflammatory responses. This highly complex system involves numerous microbiota-derived factors. The gut symbiont

  3. Automated postural responses are modified in a functional manner by instruction.

    NARCIS (Netherlands)

    Weerdesteijn, V.G.M.; Laing, A.C.; Robinovitch, S.N.

    2008-01-01

    The restoration of upright balance after a perturbation relies on highly automated and, to a large extent, stereotyped postural responses. Although these responses occur before voluntary control comes into play, previous research has shown that they can be functionally modulated on the basis of

  4. Person Response Functions and the Definition of Units in the Social Sciences

    Science.gov (United States)

    Engelhard, George, Jr.; Perkins, Aminah F.

    2011-01-01

    Humphry (this issue) has written a thought-provoking piece on the interpretation of item discrimination parameters as scale units in item response theory. One of the key features of his work is the description of an item response theory (IRT) model that he calls the logistic measurement function that combines aspects of two traditions in IRT that…

  5. Scattering from isotropic plasma coated nihility sphere

    Science.gov (United States)

    Hussan, M. M.; Ghaffar, A.; Alkanhal, Majeed A. S.; Naz, M. Y.; Ur Rehman, Sajjad; Khan, Y.

    2017-06-01

    In this study, it is observed that when an isotropic collisional plasma coating layer is produced on a nihility sphere, its back scattering efficiency becomes non-zero. Field equations, at each interface, are expanded in terms of spherical wave vector functions (SWVFs) by enforcing the extended classical wave scattering theory. Electromagnetic boundary conditions are applied at both interfaces, i.e., free space-plasma and plasma layer-nihility sphere core to obtain the scattering coefficients. The obtained scattering coefficients are used to calculate the forward scattering, back scattering, and extinction efficiencies. The obtained computational results show that an increase in collisional frequency causes a decrease in both forward and backscattered efficiencies and an increase in extinction efficiency. Furthermore, the numerical results indicate that an increase in plasma density causes an increase in both forward and backscattered efficiencies and a decrease in extinction efficiency.

  6. Large momentum transfer scattering and hadronic bremsstrahlung

    CERN Document Server

    Blankenbecler, Richard

    1975-01-01

    The interchange theory provides a simple picture of large momentum transfer scattering which correlates many features of hadrons and their interactions. It is simple to compute and has considerable predictive power. It unites the electromagnetic structure of hadrons as expressed through their form factors and inelastic structure functions with elastic and inelastic hadron-hadron scattering. The theory joins smoothly onto Regge behavior which controls forward scattering and in fact predicts such behaviour. The unified description of large and small momentum transfer scattering provided by the interchange model should allow considerable insight into the interaction of hadrons and their possible composite nature. It already yields a remarkably simple quantitative description which seems valid all the way from large angle elastic scattering at 5 GeV/c to inclusive scattering at the CERN-ISR. (13 refs).

  7. Optical phantoms with adjustable subdiffusive scattering parameters

    Science.gov (United States)

    Krauter, Philipp; Nothelfer, Steffen; Bodenschatz, Nico; Simon, Emanuel; Stocker, Sabrina; Foschum, Florian; Kienle, Alwin

    2015-10-01

    A new epoxy-resin-based optical phantom system with adjustable subdiffusive scattering parameters is presented along with measurements of the intrinsic absorption, scattering, fluorescence, and refractive index of the matrix material. Both an aluminium oxide powder and a titanium dioxide dispersion were used as scattering agents and we present measurements of their scattering and reduced scattering coefficients. A method is theoretically described for a mixture of both scattering agents to obtain continuously adjustable anisotropy values g between 0.65 and 0.9 and values of the phase function parameter γ in the range of 1.4 to 2.2. Furthermore, we show absorption spectra for a set of pigments that can be added to achieve particular absorption characteristics. By additional analysis of the aging, a fully characterized phantom system is obtained with the novelty of g and γ parameter adjustment.

  8. Calculations of spin response functions in rings with Siberian Snakes and spin rotators

    Directory of Open Access Journals (Sweden)

    Yu. M. Shatunov

    2009-02-01

    Full Text Available The so-called spin response formalism, which is linear response theory applied to spin dynamics in storage rings, can calculate the resonance strengths for spin flippers in storage rings of arbitrary structure, including rings with Siberian Snakes and spin rotators. We calculate so-called spin response functions for a model of the RHIC lattice, for various scenarios of spin rotator settings.

  9. Functional response to cholinesterase inhibitor therapy in a naturalistic Alzheimer’s disease cohort

    Directory of Open Access Journals (Sweden)

    Wattmo Carina

    2012-11-01

    Full Text Available Abstract Background Activities of daily living (ADL are an essential part of the diagnostic criteria for Alzheimer’s disease (AD. A decline in ADL affects independent living and has a strong negative impact on caregiver burden. Functional response to cholinesterase inhibitor (ChEI treatment and factors that might influence this response in naturalistic AD patients need investigating. The aim of this study was to identify the socio-demographic and clinical factors that affect the functional response after 6 months of ChEI therapy. Methods This prospective, non-randomised, multicentre study in a routine clinical setting included 784 AD patients treated with donepezil, rivastigmine or galantamine. At baseline and after 6 months of treatment, patients were assessed using several rating scales, including the Instrumental Activities of Daily Living (IADL scale, Physical Self-Maintenance Scale (PSMS and Mini-Mental State Examination (MMSE. Demographic and clinical characteristics were investigated at baseline. The functional response and the relationships of potential predictors were analysed using general linear models. Results After 6 months of ChEI treatment, 49% and 74% of patients showed improvement/no change in IADL and in PSMS score, respectively. The improved/unchanged patients exhibited better cognitive status at baseline; regarding improved/unchanged PSMS, patients were younger and used fewer anti-depressants. A more positive functional response to ChEI was observed in younger individuals or among those having the interaction effect of better preserved cognition and lower ADL ability. Patients with fewer concomitant medications or those using NSAIDs/acetylsalicylic acid showed a better PSMS response. Conclusions Critical characteristics that may influence the functional response to ChEI in AD were identified. Some predictors differed from those previously shown to affect cognitive response, e.g., lower cognitive ability and older age

  10. ERP Responses to Violations in the Hierarchical Structure of Functional Categories in Japanese Verb Conjugation

    Science.gov (United States)

    Kobayashi, Yuki; Sugioka, Yoko; Ito, Takane

    2018-01-01

    An event-related potential experiment was conducted in order to investigate readers' response to violations in the hierarchical structure of functional categories in Japanese, an agglutinative language where functional heads like Negation (Neg) as well as Tense (Tns) are realized as suffixes. A left-lateralized negativity followed by a P600 was…

  11. Lung function and bronchial responsiveness after Mycoplasma pneumoniae infection in early childhood

    DEFF Research Database (Denmark)

    Boysen, Birgitte Kjær; Jensen, Jørgen S; Nielsen, Kim G

    2008-01-01

    by whole-body plethysmography and bronchial hyperresponsiveness was assessed by cold, dry air hyperventilation. Neither baseline lung function nor bronchial response to cold dry air hyperventilation differed between M. pneumoniae-positive and -negative children: mean baseline lung function were 1.17 versus...

  12. Linking and Psychological Functioning in a Chinese Sample: The Multiple Mediation of Response to Positive Affect

    Science.gov (United States)

    Yang, Hongfei; Li, Juan

    2016-01-01

    The present study examined the associations between linking, response to positive affect, and psychological functioning in Chinese college students. The results of conducting multiple mediation analyses indicated that emotion- and self-focused positive rumination mediated the relationship between linking and psychological functioning, whereas…

  13. Intake rates and the functional response in shorebirds (Charadriiformes) eating macro-invertebrates

    NARCIS (Netherlands)

    Goss-Custard, John D.; West, Andrew D.; Yates, Michael G.; Caldow, Richard W. G.; Stillman, Richard A.; Bardsley, Louise; Castilla, Juan; Castro, Macarena; Dierschke, Volker; Durell, Sarah E. A. Le V. Dit; Eichhorn, Goetz; Ens, Bruno J.; Exo, Klaus-Michael; Udayangani-Fernando, P. U.; Ferns, Peter N.; Hockey, Philip A. R.; Gill, Jennifer A.; Johnstone, Ian; Kalejta-Summers, Bozena; Masero, Jose A.; Moreira, Francisco; Nagarajan, Rajarathina Velu; Owens, Ian P. F.; Pacheco, Cristian; Perez-Hurtado, Alejandro; Rogers, Danny; Scheiffarth, Gregor; Sitters, Humphrey; Sutherland, William J.; Triplet, Patrick; Worrall, Dave H.; Zharikov, Yuri; Zwarts, Leo; Pettifor, Richard A.

    2006-01-01

    As field determinations take much effort, it would be useful to be able to predict easily the coefficients describing the functional response of free-living predators, the function relating food intake rate to the abundance of food organisms in the environment. As a means easily to parameterise an

  14. Self-reported social functioning and prefrontal hemodynamic responses during a cognitive task in schizophrenia.

    Science.gov (United States)

    Pu, Shenghong; Nakagome, Kazuyuki; Itakura, Masashi; Yamanashi, Takehiko; Sugie, Takuya; Miura, Akehiko; Satake, Takahiro; Iwata, Masaaki; Nagata, Izumi; Kaneko, Koichi

    2015-10-30

    Impaired social functioning is a characteristic of schizophrenia that affects patients' quality of life. The aim of the study was to assess prefrontal hemodynamic responses during a cognitive task and establish its influence on psychiatric symptoms, cognitive function, global functioning, and self-reported social functioning in patients with schizophrenia. Thirty-three patients with schizophrenia and 30 age-and sex-matched healthy controls participated in the study. We measured hemodynamic responses in the prefrontal and superior temporal cortical surface areas with 52-channel near-infrared spectroscopy (NIRS) during a verbal fluency task (VFT). Self-reported social functioning was assessed using the Social Functioning Scale (SFS). Regional hemodynamic responses were significantly smaller in the prefrontal and temporal regions in subjects with schizophrenia than in the controls, and prefrontal hemodynamic responses during the VFT showed a strong correlation with SFS total scores. These results suggest an association between self-reported social functioning and prefrontal activation in subjects with schizophrenia. The present study provides evidence that NIRS imaging could be helpful in understanding the neural basis of social functioning. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Responsiveness of the OARSI-OMERACT osteoarthritis pain and function measures

    DEFF Research Database (Denmark)

    Bond, M; Davis, A; Lohmander, Stefan

    2012-01-01

    To assess the responsiveness of the Intermittent and Constant Osteoarthritis Pain (ICOAP) measure, Hip Disability and Osteoarthritis Outcome Score Physical Function Short Form (HOOS-PS), and the Knee Disability and Osteoarthritis Outcome Score Physical Function Short Form (KOOS-PS) in a pharmacol...

  16. Functional Characterization of Type-B Response Regulators in the Arabidopsis Cytokinin Response1[W][OA

    Science.gov (United States)

    Hill, Kristine; Mathews, Dennis E.; Kim, Hyo Jung; Street, Ian H.; Wildes, Sarah L.; Chiang, Yi-Hsuan; Mason, Michael G.; Alonso, Jose M.; Ecker, Joseph R.; Kieber, Joseph J.; Schaller, G. Eric

    2013-01-01

    Cytokinins play critical roles in plant growth and development, with the transcriptional response to cytokinin being mediated by the type-B response regulators. In Arabidopsis (Arabidopsis thaliana), type-B response regulators (ARABIDOPSIS RESPONSE REGULATORS [ARRs]) form three subfamilies based on phylogenic analysis, with subfamily 1 having seven members and subfamilies 2 and 3 each having two members. Cytokinin responses are predominantly mediated by subfamily 1 members, with cytokinin-mediated effects on root growth and root meristem size correlating with type-B ARR expression levels. To determine which type-B ARRs can functionally substitute for the subfamily 1 members ARR1 or ARR12, we expressed different type-B ARRs from the ARR1 promoter and assayed their ability to rescue arr1 arr12 double mutant phenotypes. ARR1, as well as a subset of other subfamily 1 type-B ARRs, restore the cytokinin sensitivity to arr1 arr12. Expression of ARR10 from the ARR1 promoter results in cytokinin hypersensitivity and enhances shoot regeneration from callus tissue, correlating with enhanced stability of the ARR10 protein compared with the ARR1 protein. Examination of transfer DNA insertion mutants in subfamilies 2 and 3 revealed little effect on several well-characterized cytokinin responses. However, a member of subfamily 2, ARR21, restores cytokinin sensitivity to arr1 arr12 roots when expressed from the ARR1 promoter, indicating functional conservation of this divergent family member. Our results indicate that the type-B ARRs have diverged in function, such that some, but not all, can complement the arr1 arr12 mutant. In addition, our results indicate that type-B ARR expression profiles in the plant, along with posttranscriptional regulation, play significant roles in modulating their contribution to cytokinin signaling. PMID:23482873

  17. Analysis of experimental data on doublet neutron-deuteron scattering at energies below the deuteron-breakup threshold on the basis of the pole approximation of the effective-range function

    Energy Technology Data Exchange (ETDEWEB)

    Babenko, V. A.; Petrov, N. M., E-mail: pet@online.com.ua [National Academy of Sciences of Ukraine, Bogolyubov Institute for Theoretical Physics (Ukraine)

    2008-01-15

    On the basis of the Bargmann representation of the S matrix, the pole approximation is obtained for the effective-range function k cot {delta}. This approximation is optimal for describing the neutron-deuteron system in the doublet spin state. The values of r{sub 0} = 412.469 fm and v{sub 2} = -35 495.62 fm{sup 3} for the doublet low-energy parameters of neutron-deuteron scattering and the value of D = 172.678 fm{sup 2} for the respective pole parameter are deduced by using experimental results for the triton binding energy E{sub T}, the doublet neutron-deuteron scattering length a{sub 2}, and van Oers-Seagrave phase shifts at energies below the deuteron-breakup threshold. With these parameters, the pole approximation of the effective-range function provides a highly precise description (the relative error does not exceed 1%) of the doublet phase shift for neutron-deuteron scattering at energies below the deuteron-breakup threshold. Physical properties of the triton in the ground (T) and virtual (v) states are calculated. The results are B{sub v} = 0.608 MeV for the virtuallevel position and C{sub T}{sup 2} = 2.866 and C{sub v}{sup 2} = 0.0586 for the dimensionless asymptotic normalization constants. It is shown that, in the Whiting-Fuda approximation, the values of physical quantities characterizing the triton virtual state are determined to a high precision by one parameter, the doublet neutron-deuteron scattering length a{sub 2}. The effective triton radii in the ground ({rho}{sub T} = 1.711 fm) and virtual ({rho}{sub v} = 74.184 fm) states are calculated for the first time.

  18. Opposing Responses of Bird Functional Diversity to Vegetation Structural Diversity in Wet and Dry Forest

    OpenAIRE

    Sitters, Holly; York, Alan; Swan, Matthew; Christie, Fiona; Di Stefano, Julian

    2016-01-01

    Disturbance regimes are changing worldwide, and the consequences for ecosystem function and resilience are largely unknown. Functional diversity (FD) provides a surrogate measure of ecosystem function by capturing the range, abundance and distribution of trait values in a community. Enhanced understanding of the responses of FD to measures of vegetation structure at landscape scales is needed to guide conservation management. To address this knowledge gap, we used a whole-of-landscape samplin...

  19. Scattering Solar Thermal Concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Giebink, Noel C. [Pennsylvania State Univ., State College, PA (United States)

    2015-01-31

    concentrator optical efficiency was found to decrease significantly with increasing aperture width beyond 0.5 m due to parasitic waveguide out-coupling loss and low-level absorption that become dominant at larger scale. A heat transfer model was subsequently implemented to predict collector fluid heat gain and outlet temperature as a function of flow rate using the optical model as a flux input. It was found that the aperture width size limitation imposed by the optical efficiency characteristics of the waveguide limits the absolute optical power delivered to the heat transfer element per unit length. As compared to state-of-the-art parabolic trough CPV system aperture widths approaching 5 m, this limitation leads to an approximate factor of order of magnitude increase in heat transfer tube length to achieve the same heat transfer fluid outlet temperature. The conclusion of this work is that scattering solar thermal concentration cannot be implemented at the scale and efficiency required to compete with the performance of current parabolic trough CSP systems. Applied within the alternate context of CPV, however, the results of this work have likely opened up a transformative new path that enables quasi-static, high efficiency CPV to be implemented on rooftops in the form factor of traditional fixed-panel photovoltaics.

  20. Electron-electron scattering in linear transport in two-dimensional systems

    DEFF Research Database (Denmark)

    Hu, Ben Yu-Kuang; Flensberg, Karsten

    1996-01-01

    We describe a method for numerically incorporating electron-electron scattering in quantum wells for small deviations of the distribution function from equilibrium, within the framework of the Boltzmann equation. For a given temperature T and density n, a symmetric matrix needs to be evaluated only...... once, and henceforth it can be used to describe electron-electron scattering in any Boltzmann equation linear-response calculation for that particular T and n. Using this method, we calculate the distribution function and mobility for electrons in a quantum well, including full finite...

  1. Response functions of imaging plates to photons, electrons and 4He particles.

    Science.gov (United States)

    Bonnet, T; Comet, M; Denis-Petit, D; Gobet, F; Hannachi, F; Tarisien, M; Versteegen, M; Aléonard, M M

    2013-10-01

    Imaging plates from Fuji (BAS-SR, MS, and TR types) are phosphor films routinely used in ultra high intensity laser experiments. However, few data are available on the absolute IP response functions to ionizing particles. We have previously measured and modeled the IP response functions to protons. We focus here on the determination of the responses to photons, electrons, and (4)He particles. The response functions are obtained on an energy range going from a few tens of keV to a few tens of MeV and are compared to available data. The IP sensitivities to the different ionizing particles demonstrate a quenching effect depending on the particle stopping power.

  2. Binaural-level functions in ferret auditory cortex: evidence for a continuous distribution of response properties.

    Science.gov (United States)

    Campbell, Robert A A; Schnupp, Jan W H; Shial, Akhil; King, Andrew J

    2006-06-01

    Many previous studies have subdivided auditory neurons into a number of physiological classes according to various criteria applied to their binaural response properties. However, it is often unclear whether such classifications represent discrete classes of neurons or whether they merely reflect a potentially convenient but ultimately arbitrary partitioning of a continuous underlying distribution of response properties. In this study we recorded the binaural response properties of 310 units in the auditory cortex of anesthetized ferrets, using an extensive range of interaural level differences (ILDs) and average binaural levels (ABLs). Most recordings were from primary auditory fields on the middle ectosylvian gyrus and from neurons with characteristic frequencies >5 kHz. We used simple multivariate statistics to quantify a fundamental coding feature: the shapes of the binaural response functions. The shapes of all 310 binaural response surfaces were represented as points in a five-dimensional principal component space. This space captured the underlying shape of all the binaural response surfaces. The distribution of binaural level functions was not homogeneous because some shapes were more common than others. Despite this, clustering validation techniques revealed no evidence for the existence of discrete, or partially overlapping, clusters that could serve as a basis for an objective classification of binaural-level functions. We also examined the gradients of the response functions for the population of units; these gradients were greatest near the midline, which is consistent with free-field data showing that cortical neurons are most sensitive to changes in stimulus location in this region of space.

  3. Functional diversity response to hardwood forest management varies across taxa and spatial scales.

    Science.gov (United States)

    Murray, Bryan D; Holland, Jeffrey D; Summerville, Keith S; Dunning, John B; Saunders, Michael R; Jenkins, Michael A

    2017-06-01

    Contemporary forest management offers a trade-off between the potential positive effects of habitat heterogeneity on biodiversity, and the potential harm to mature forest communities caused by habitat loss and perforation of the forest canopy. While the response of taxonomic diversity to forest management has received a great deal of scrutiny, the response of functional diversity is largely unexplored. However, functional diversity may represent a more direct link between biodiversity and ecosystem function. To examine how forest management affects diversity at multiple spatial scales, we analyzed a long-term data set that captured changes in taxonomic and functional diversity of moths (Lepidoptera), longhorned beetles (Coleoptera: Cerambycidae), and breeding birds in response to contemporary silvicultural systems in oak-hickory hardwood forests. We used these data sets to address the following questions: how do even- and uneven-aged silvicultural systems affect taxonomic and functional diversity at the scale of managed landscapes compared to the individual harvested and unharvested forest patches that comprise the landscapes, and how do these silvicultural systems affect the functional similarity of assemblages at the scale of managed landscapes and patches? Due to increased heterogeneity within landscapes, we expected even-aged silviculture to increase and uneven-aged silviculture to decrease functional diversity at the landscape level regardless of impacts at the patch level. Functional diversity responses were taxon-specific with respect to the direction of change and time since harvest. Responses were also consistent across patch and landscape levels within each taxon. Moth assemblage species richness, functional richness, and functional divergence were negatively affected by harvesting, with stronger effects resulting from uneven-aged than even-aged management. Longhorned beetle assemblages exhibited a peak in species richness two years after harvesting

  4. Functional diversity and community assembly of river invertebrates show globally consistent responses to decreasing glacier cover.

    Science.gov (United States)

    Brown, Lee E; Khamis, Kieran; Wilkes, Martin; Blaen, Phillip; Brittain, John E; Carrivick, Jonathan L; Fell, Sarah; Friberg, Nikolai; Füreder, Leopold; Gislason, Gisli M; Hainie, Sarah; Hannah, David M; James, William H M; Lencioni, Valeria; Olafsson, Jon S; Robinson, Christopher T; Saltveit, Svein J; Thompson, Craig; Milner, Alexander M

    2018-02-01

    Global change threatens invertebrate biodiversity and its central role in numerous ecosystem functions and services. Functional trait analyses have been advocated to uncover global mechanisms behind biodiversity responses to environmental change, but the application of this approach for invertebrates is underdeveloped relative to other organism groups. From an evaluation of 363 records comprising >1.23 million invertebrates collected from rivers across nine biogeographic regions on three continents, consistent responses of community trait composition and diversity to replicated gradients of reduced glacier cover are demonstrated. After accounting for a systematic regional effect of latitude, the processes shaping river invertebrate functional diversity are globally consistent. Analyses nested within individual regions identified an increase in functional diversity as glacier cover decreases. Community assembly models demonstrated that dispersal limitation was the dominant process underlying these patterns, although environmental filtering was also evident in highly glacierized basins. These findings indicate that predictable mechanisms govern river invertebrate community responses to decreasing glacier cover globally.

  5. Addressing the Photometric Calibration Challenge: Explicit Determination of the Instrumental Response and Atmospheric Response Functions, and Tying it All Together.

    Science.gov (United States)

    Stubbs, C. W.; Tonry, J. L.

    2016-05-01

    Photometric calibration is currently the dominant source of systematic uncertainty in exploiting type Ia supernovae to determine the nature of the dark energy. We review our ongoing program to address this calibration challenge by performing measurements of both the instrumental response function and the optical transmission function of the atmosphere. A key aspect of this approach is to complement standard star observations by using NIST-calibrated photodiodes as a metrology foundation for optical flux measurements. We present our first attempt to assess photometric consistency between synthetic photometry and observations, by comparing predictions based on a NIST-diode-based determination of the PanSTARRS-1 instrumental response and empirical atmospheric transmission measurements, with fluxes we obtained from observing spectrophotometric standards.

  6. Prefrontal response and frontostriatal functional connectivity to monetary reward in abstinent alcohol-dependent young adults.

    Directory of Open Access Journals (Sweden)

    Erika E Forbes

    Full Text Available Although altered function in neural reward circuitry is widely proposed in models of addiction, more recent conceptual views have emphasized the role of disrupted response in prefrontal regions. Changes in regions such as the orbitofrontal cortex, medial prefrontal cortex, and dorsolateral prefrontal cortex are postulated to contribute to the compulsivity, impulsivity, and altered executive function that are central to addiction. In addition, few studies have examined function in these regions during young adulthood, when exposure is less chronic than in typical samples of alcohol-dependent adults. To address these issues, we examined neural response and functional connectivity during monetary reward in 24 adults with alcohol dependence and 24 psychiatrically healthy adults. Adults with alcohol dependence exhibited less response to the receipt of monetary reward in a set of prefrontal regions including the medial prefrontal cortex, lateral orbitofrontal cortex, and dorsolateral prefrontal cortex. Adults with alcohol dependence also exhibited greater negative correlation between function in each of these regions and that in the nucleus accumbens. Within the alcohol-dependent group, those with family history of alcohol dependence exhibited lower mPFC response, and those with more frequent drinking exhibited greater negative functional connectivity between the mPFC and the nucleus accumbens. These findings indicate that alcohol dependence is associated with less engagement of prefrontal cortical regions, suggesting weak or disrupted regulation of ventral striatal response. This pattern of prefrontal response and frontostriatal connectivity has consequences for the behavior patterns typical of addiction. Furthermore, brain-behavior findings indicate that the potential mechanisms of disruption in frontostriatal circuitry in alcohol dependence include family liability to alcohol use problems and more frequent use of alcohol. In all, these findings

  7. Prefrontal response and frontostriatal functional connectivity to monetary reward in abstinent alcohol-dependent young adults.

    Science.gov (United States)

    Forbes, Erika E; Rodriguez, Eric E; Musselman, Samuel; Narendran, Rajesh

    2014-01-01

    Although altered function in neural reward circuitry is widely proposed in models of addiction, more recent conceptual views have emphasized the role of disrupted response in prefrontal regions. Changes in regions such as the orbitofrontal cortex, medial prefrontal cortex, and dorsolateral prefrontal cortex are postulated to contribute to the compulsivity, impulsivity, and altered executive function that are central to addiction. In addition, few studies have examined function in these regions during young adulthood, when exposure is less chronic than in typical samples of alcohol-dependent adults. To address these issues, we examined neural response and functional connectivity during monetary reward in 24 adults with alcohol dependence and 24 psychiatrically healthy adults. Adults with alcohol dependence exhibited less response to the receipt of monetary reward in a set of prefrontal regions including the medial prefrontal cortex, lateral orbitofrontal cortex, and dorsolateral prefrontal cortex. Adults with alcohol dependence also exhibited greater negative correlation between function in each of these regions and that in the nucleus accumbens. Within the alcohol-dependent group, those with family history of alcohol dependence exhibited lower mPFC response, and those with more frequent drinking exhibited greater negative functional connectivity between the mPFC and the nucleus accumbens. These findings indicate that alcohol dependence is associated with less engagement of prefrontal cortical regions, suggesting weak or disrupted regulation of ventral striatal response. This pattern of prefrontal response and frontostriatal connectivity has consequences for the behavior patterns typical of addiction. Furthermore, brain-behavior findings indicate that the potential mechanisms of disruption in frontostriatal circuitry in alcohol dependence include family liability to alcohol use problems and more frequent use of alcohol. In all, these findings build on the extant

  8. Vibrational absorption spectra from vibrational coupled cluster damped linear response functions calculated using an asymmetric Lanczos algorithm

    DEFF Research Database (Denmark)

    Thomsen, Bo; Hansen, Mikkel Bo; Seidler, Peter

    2012-01-01

    We report the theory and implementation of vibrational coupled cluster (VCC) damped response functions. From the imaginary part of the damped VCC response function the absorption as function of frequency can be obtained, requiring formally the solution of the now complex VCC response equations. T...

  9. Concordance and discordance between taxonomic and functional homogenization: responses of soil mite assemblages to forest conversion.

    Science.gov (United States)

    Mori, Akira S; Ota, Aino T; Fujii, Saori; Seino, Tatsuyuki; Kabeya, Daisuke; Okamoto, Toru; Ito, Masamichi T; Kaneko, Nobuhiro; Hasegawa, Motohiro

    2015-10-01

    The compositional characteristics of ecological assemblages are often simplified; this process is termed "biotic homogenization." This process of biological reorganization occurs not only taxonomically but also functionally. Testing both aspects of homogenization is essential if ecosystem functioning supported by a diverse mosaic of functional traits in the landscape is concerned. Here, we aimed to infer the underlying processes of taxonomic/functional homogenization at the local scale, which is a scale that is meaningful for this research question. We recorded species of litter-dwelling oribatid mites along a gradient of forest conversion from a natural forest to a monoculture larch plantation in Japan (in total 11 stands), and collected data on the functional traits of the recorded species to quantify functional diversity. We calculated the taxonomic and functional β-diversity, an index of biotic homogenization. We found that both the taxonomic and functional β-diversity decreased with larch dominance (stand homogenization). After further deconstructing β-diversity into the components of turnover and nestedness, which reflect different processes of community organization, a significant decrease in the response to larch dominance was observed only for the functional turnover. As a result, there was a steeper decline in the functional β-diversity than the taxonomic β-diversity. This discordance between the taxonomic and functional response suggests that species replacement occurs between species that are functionally redundant under environmental homogenization, ultimately leading to the stronger homogenization of functional diversity. The insights gained from community organization of oribatid mites suggest that the functional characteristics of local assemblages, which support the functionality of ecosystems, are of more concern in human-dominated forest landscapes.

  10. A mathematical function for the description of nutrient-response curve.

    Directory of Open Access Journals (Sweden)

    Hamed Ahmadi

    Full Text Available Several mathematical equations have been proposed to modeling nutrient-response curve for animal and human justified on the goodness of fit and/or on the biological mechanism. In this paper, a functional form of a generalized quantitative model based on Rayleigh distribution principle for description of nutrient-response phenomena is derived. The three parameters governing the curve a has biological interpretation, b may be used to calculate reliable estimates of nutrient response relationships, and c provide the basis for deriving relationships between nutrient and physiological responses. The new function was successfully applied to fit the nutritional data obtained from 6 experiments including a wide range of nutrients and responses. An evaluation and comparison were also done based simulated data sets to check the suitability of new model and four-parameter logistic model for describing nutrient responses. This study indicates the usefulness and wide applicability of the new introduced, simple and flexible model when applied as a quantitative approach to characterizing nutrient-response curve. This new mathematical way to describe nutritional-response data, with some useful biological interpretations, has potential to be used as an alternative approach in modeling nutritional responses curve to estimate nutrient efficiency and requirements.

  11. A mathematical function for the description of nutrient-response curve.

    Science.gov (United States)

    Ahmadi, Hamed

    2017-01-01

    Several mathematical equations have been proposed to modeling nutrient-response curve for animal and human justified on the goodness of fit and/or on the biological mechanism. In this paper, a functional form of a generalized quantitative model based on Rayleigh distribution principle for description of nutrient-response phenomena is derived. The three parameters governing the curve a) has biological interpretation, b) may be used to calculate reliable estimates of nutrient response relationships, and c) provide the basis for deriving relationships between nutrient and physiological responses. The new function was successfully applied to fit the nutritional data obtained from 6 experiments including a wide range of nutrients and responses. An evaluation and comparison were also done based simulated data sets to check the suitability of new model and four-parameter logistic model for describing nutrient responses. This study indicates the usefulness and wide applicability of the new introduced, simple and flexible model when applied as a quantitative approach to characterizing nutrient-response curve. This new mathematical way to describe nutritional-response data, with some useful biological interpretations, has potential to be used as an alternative approach in modeling nutritional responses curve to estimate nutrient efficiency and requirements.

  12. Measuring response saturation in human MT and MST as a function of motion density.

    Science.gov (United States)

    Durant, Szonya; Furlan, Michele

    2014-07-24

    The human brain areas MT and MST have been studied in great detail using fMRI with regards to their motion processing properties; however, to what extent this corresponds with single cell recordings remains to be fully described. Average response over human MT+ has been shown to increase linearly with motion coherence, similar to single cell responses. In response to motion density some single cell data however suggest a rapid saturation. We ask how the combination of these responses is reflected in the population response. We measured the blood oxygen level dependent (BOLD) response function of MT and MST using a motion density signal, comparing with area V1. We used spatially fixed apertures containing motion stimuli to manipulate the area covered by motion. We found that MT and MST responded above baseline to a very minimal amount of motion and showed a rather flat response to motion density, indicative of saturation. We discuss how this may be related to the size of the receptive fields and inhibitory interactions, although necessarily residual attention effects also need to be considered. We then compared different types of motion and found no difference between coherent and random motion at any motion density, suggesting that when combining response over several motion stimuli covering the visual field, a linear relationship of MT and MST population response as a function of motion coherence might not hold. © 2014 ARVO.

  13. Functional responses in animal movement explain spatial heterogeneity in animal-habitat relationships.

    Science.gov (United States)

    Mason, Tom H E; Fortin, Daniel

    2017-07-01

    Understanding why heterogeneity exists in animal-habitat spatial relationships is critical for identifying the drivers of animal distributions. Functional responses in habitat selection - whereby animals adjust their habitat selection depending on habitat availability - are useful for describing animal-habitat spatial heterogeneity. However, they could be yielded by different movement tactics, involving contrasting interspecific interactions. Identifying functional responses in animal movement, rather than in emergent spatial patterns like habitat selection, could disentangle the effects of different movement behaviours on spatial heterogeneity in animal-habitat relationships. This would clarify how functional responses in habitat selection emerge and provide a general tool for understanding the mechanistic drivers of animal distributions. We tested this approach using data from GPS-collared woodland caribou (Rangifer tarandus), a prey species under top-down control. We tested how caribou selected and moved with respect to a key resource (lichen-conifer stands) as a function of the availability of surrounding refuge land-cover (closed-conifer stands), using step selection functions. Caribou selected resource patches more strongly in areas richer in refuge land-cover - a functional response in habitat selection. However, adjustments in multiple movement behaviours could have generated this pattern: stronger directed movement towards resource patches and/or longer residency within resource patches, in areas richer in refuges. Different contributions of these behaviours would produce contrasting forager spatial dynamics. We identified functional responses in both movement behaviours: caribou were more likely to move towards resource patches in areas richer in refuge land-cover, and to remain in these patches during movement steps. This tactic enables caribou to forage for longer in safer areas where they can rapidly seek refuge in dense cover when predators are

  14. Novel response function resolves by image deconvolution more details of surface nanomorphology

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    2010-01-01

    A novel method of image processing is presented which relies on deconvolution of data using the response function of the apparatus. It is revealed that all the surface structures observed by digital imaging are generated by a convolution of the response function of the apparatus with the surfaces...... of distances, correction for drift phenomena and rotation in the plane of the surface. The technology may subsequently reveal more details of molecular adsorbents. The impact of in situ STM at atomic and lower resolution on imaging is discussed in the paper.......A novel method of image processing is presented which relies on deconvolution of data using the response function of the apparatus. It is revealed that all the surface structures observed by digital imaging are generated by a convolution of the response function of the apparatus with the surfaces......’ nanomorphology, which provided images of convoluted physical structures rather than images of real physical structures. In order to restore the genuine physical information on surface structures, a deconvolution using a novel response function of the feedback circuitry is required. At the highest resolution...

  15. Numerical and functional responses of intestinal helminths in three rajid skates: evidence for competition between parasites?

    Science.gov (United States)

    Randhawa, Haseeb S

    2012-11-01

    Host-parasite interactions generally involve communities of parasites. Within these communities, species will co-exist and/or interact with one another in a manner either benefiting the species involved or to the detriment of one or more of the species. At the level of helminth infracommunities, evidence for intra- and inter-specific competition includes numerical responses, i.e. those regulating helminth intensity of infection, and functional responses, i.e. where the presence of competitors modifies the realised niche of infrapopulations. The objectives of this study are to assess the numerical and functional responses of helminths in infracommunities from 3 rajid skates using general linear models. Despite a lack of numerical responses, functional responses to intra- and inter-specific interactions were observed. A positive correlation between the number of individuals in an infrapopulation and its niche breadth (functional response) was observed for the tapeworms Pseudanthobothrium spp. and Echeneibothrium spp., in all their respective hosts, and for the nematode Pseudanisakis sp. in the little skate. Evidence for inter-specific competition includes niche shifts in Pseudanthobothrium purtoni (ex little skate) and Pseudanisakis sp. (ex thorny skate) in the presence of Pseudanisakis sp. and the tapeworm Grillotia sp., respectively. These results are consistent with other studies in providing evidence for competition between helminths of skates.

  16. Catecholamine Responses to Virtual Combat: Implications for Post-Traumatic Stress and Dimensions of Functioning

    Directory of Open Access Journals (Sweden)

    Krista Beth Highland

    2015-03-01

    Full Text Available PTSD symptoms can result in functional impairment among service members (SMs, even in those without a clinical diagnosis. The variability in outcomes may be related to underlying catecholamine mechanisms. Individuals with PTSD tend to have elevated basal catecholamine levels, though less is known regarding catecholamine responses to trauma-related stimuli. We assessed whether catecholamine responses to a virtual combat environment impact the relationship between PTSD symptom clusters and elements of functioning. Eighty-seven clinically healthy SMs, within 2 months after deployment to Iraq or Afghanistan, completed self-report measures, viewed virtual-reality (VR combat sequences, and had sequential blood draws. Norepinephrine responses to VR combat exposure moderated the relationship between avoidance symptoms and scales of functioning including physical functioning, physical-role functioning, and vitality. Among those with high levels of avoidance, norepinephrine change was inversely associated with functional status, whereas a positive correlation was observed for those with low levels of avoidance. Our findings represent a novel use of a virtual environment to display combat-related stimuli to returning SMs to elucidate mind-body connections inherent in their responses. The insight gained improves our understanding of post-deployment symptoms and quality of life in SMs and may facilitate enhancements in treatment. Further research is needed to validate these findings in other populations and to define the implications for treatment effectiveness.

  17. Executive functioning complaints and escitalopram treatment response in late-life depression.

    Science.gov (United States)

    Manning, Kevin J; Alexopoulos, George S; Banerjee, Samprit; Morimoto, Sarah Shizuko; Seirup, Joanna K; Klimstra, Sibel A; Yuen, Genevieve; Kanellopoulos, Theodora; Gunning-Dixon, Faith

    2015-05-01

    Executive dysfunction may play a key role in the pathophysiology of late-life depression. Executive dysfunction can be assessed with cognitive tests and subjective report of difficulties with executive skills. The present study investigated the association between subjective report of executive functioning complaints and time to escitalopram treatment response in older adults with major depressive disorder (MDD). 100 older adults with MDD (58 with executive functioning complaints and 42 without executive functioning complaints) completed a 12-week trial of escitalopram. Treatment response over 12 weeks, as measured by repeated Hamilton Depression Rating Scale scores, was compared for adults with and without executive complaints using mixed-effects modeling. Mixed effects analysis revealed a significant group × time interaction, F(1, 523.34) = 6.00, p = 0.01. Depressed older adults who reported executive functioning complaints at baseline demonstrated a slower response to escitalopram treatment than those without executive functioning complaints. Self-report of executive functioning difficulties may be a useful prognostic indicator for subsequent speed of response to antidepressant medication. Copyright © 2015 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

  18. Are transcriptional responses to inbreeding a functional response to alleviate inbreeding depression?

    Science.gov (United States)

    García, Carlos; Ávila, Victoria; Quesada, Humberto; Caballero, Armando

    2013-01-01

    Previous studies addressing the relationship between gene regulation and inbreeding depression did not allow for discerning the changes that alleviate the depression from those that generate it. We directly addressed this question by analyzing changes in gene expression, using Affymetrix 2.0 arrays in Drosophila melanogaster inbred sublines differing in their magnitudes of inbreeding depression relative to the expression in an outbred control. The total number of arrays analyzed was 27, with 9,133 probe sets showing a significant signal of expression. We found that for those genes differentially expressed between inbred and outbred sublines, most of them showed a pattern of expression consistent with a protective role against inbreeding effects. The observed increase in depression was presumably related to an inability of the genome to do the appropriate expression adjustments. Expression changes detected in our study showed a clear specificity of RNA-splicing and energy derivation functions. Thus, it appears that most of the observed changes in gene expression associated with inbreeding may occur predominantly to alleviate inbreeding depression, i.e., as a protection against the effects of inbreeding.

  19. Universal chaotic scattering on quantum graphs.

    Science.gov (United States)

    Pluhař, Z; Weidenmüller, H A

    2013-01-18

    We calculate the S-matrix correlation function for chaotic scattering on quantum graphs and show that it agrees with that of random-matrix theory. We also calculate all higher S-matrix correlation functions in the Ericson regime. These, too, agree with random-matrix theory results as far as the latter are known. We conjecture that our results give a universal description of chaotic scattering.

  20. Note: Light output enhanced fast response and low afterglow 6Li glass scintillator as potential down-scattered neutron diagnostics for inertial confinement fusion.

    Science.gov (United States)

    Arikawa, Yasunobu; Yamanoi, Kohei; Nagai, Takahiro; Watanabe, Kozue; Kouno, Masahiro; Sakai, Kohei; Nakazato, Tomoharu; Shimizu, Toshihiko; Cadatal, Marilou Raduban; Estacio, Elmer Surat; Sarukura, Nobuhiko; Nakai, Mitsuo; Norimatsu, Takayoshi; Azechi, Hiroshi; Murata, Takahiro; Fujino, Shigeru; Yoshida, Hideki; Izumi, Nobuhiko; Satoh, Nakahiro; Kan, Hirofumi

    2010-10-01

    The characteristics of an APLF80+3Ce scintillator are presented. Its sufficiently fast decay profile, low afterglow, and an improved light output compared to the recently developed APLF80+3Pr, were experimentally demonstrated. This scintillator material holds promise for applications in neutron imaging diagnostics at the energy regions of 0.27 MeV of DD fusion down-scattered neutron peak at the world's largest inertial confinement fusion facilities such as the National Ignition Facility and the Laser Mégajoule.

  1. Rayleigh scattering of Moessbauer radiation in hyaluronate oriented fibres

    Energy Technology Data Exchange (ETDEWEB)

    Albanese, G.; Cavatorta, F.; Deriu, A. [Parma Univ. (Italy). Dip. di Fisica]|[Istituto Nazionale di Fisica della Materia, Parma (Italy); Rupprecht, A. [Stockholm Univ. (Sweden). Dep. of Physical Chemistry

    1996-02-01

    The Rayleigh scattering of Moessbauer radiation has been measured on highly oriented fibres of Na-hyaluronate at different hydration levels. The elastic- and-inelastic-scattering intensities, measured as a function of the scattering vector Q, have provided information on the dynamic structuring of the water molecules to the polysaccharidic chains.

  2. Generation of the neutron response function of an NE213 scintillator for fusion applications

    Science.gov (United States)

    Binda, F.; Eriksson, J.; Ericsson, G.; Hellesen, C.; Conroy, S.; Nocente, M.; Sundén, E. Andersson; JET Contributors

    2017-09-01

    In this work we present a method to evaluate the neutron response function of an NE213 liquid scintillator. This method is particularly useful when the proton light yield function of the detector has not been measured, since it is based on a proton light yield function taken from literature, MCNPX simulations, measurements of gamma-rays from a calibration source and measurements of neutrons from fusion experiments with ohmic plasmas. The inclusion of the latter improves the description of the proton light yield function in the energy range of interest (around 2.46 MeV). We apply this method to an NE213 detector installed at JET, inside the radiation shielding of the magnetic proton recoil (MPRu) spectrometer, and present the results from the calibration along with some examples of application of the response function to perform neutron emission spectroscopy (NES) of fusion plasmas. We also investigate how the choice of the proton light yield function affects the NES analysis, finding that the result does not change significantly. This points to the fact that the method for the evaluation of the neutron response function is robust and gives reliable results.

  3. Constrained Ordination Analysis with Enrichment of Bell-Shaped Response Functions.

    Directory of Open Access Journals (Sweden)

    Yingjie Zhang

    Full Text Available Constrained ordination methods aims at finding an environmental gradient along which the species abundances are maximally separated. The species response functions, which describe the expected abundance as a function of the environmental score, are according to the ecological fundamental niche theory only meaningful if they are bell-shaped. Many classical model-based ordination methods, however, use quadratic regression models without imposing the bell-shape and thus allowing for meaningless U-shaped response functions. The analysis output (e.g. a biplot may therefore be potentially misleading and the conclusions are prone to errors. In this paper we present a log-likelihood ratio criterion with a penalisation term to enforce more bell-shaped response shapes. We report the results of a simulation study and apply our method to metagenomics data from microbial ecology.

  4. Cochlear Responses and Auditory Brainstem Response Functions in Adults with Auditory Neuropathy/ Dys-Synchrony and Individuals with Normal Hearing

    Directory of Open Access Journals (Sweden)

    Zahra Jafari

    2007-06-01

    Full Text Available Background and Aim: Physiologic measures of cochlear and auditory nerve function may be of assis¬tance in distinguishing between hearing disorders due primarily to auditory nerve impairment from those due primarily to cochlear hair cells dysfunction. The goal of present study was to measure of co-chlear responses (otoacoustic emissions and cochlear microphonics and auditory brainstem response in some adults with auditory neuropathy/ dys-synchrony and subjects with normal hearing. Materials and Methods: Patients were 16 adults (32 ears in age range of 14-30 years with auditory neu¬ropathy/ dys-synchrony and 16 individuals in age range of 16-30 years from both sexes. The results of transient otoacoustic emissions, cochlear microphonics and auditory brainstem response measures were compared in both groups and the effects of age, sex, ear and degree of hearing loss were studied. Results: The pure-tone average was 48.1 dB HL in auditory neuropathy/dys-synchrony group and the fre¬quency of low tone loss and flat audiograms were higher among other audiogram's shapes. Transient oto¬acoustic emissions were shown in all auditory neuropathy/dys-synchrony people except two cases and its average was near in both studied groups. The latency and amplitude of the biggest reversed co-chlear microphonics response were higher in auditory neuropathy/dys-synchrony patients than control peo¬ple significantly. The correlation between cochlear microphonics amplitude and degree of hearing loss was not significant, and age had significant effect in some cochlear microphonics measures. Audi-tory brainstem response had no response in auditory neuropathy/dys-synchrony patients even with low stim¬uli rates. Conclusion: In adults with speech understanding worsen than predicted from the degree of hearing loss that suspect to auditory neuropathy/ dys-synchrony, the frequency of low tone loss and flat audiograms are higher. Usually auditory brainstem response is absent in

  5. Bronchodilator response of advanced lung function parameters depending on COPD severity

    Directory of Open Access Journals (Sweden)

    Jarenbäck L

    2016-11-01

    Full Text Available Linnea Jarenbäck,1 Göran Eriksson,1 Stefan Peterson,2 Jaro Ankerst,1 Leif Bjermer,1 Ellen Tufvesson1 1Respiratory Medicine and Allergology, Department of Clinical Sciences Lund, Lund University, 2Regional Cancer Center South, Skåne University Hospital, Lund, Sweden Background: COPD is defined as partly irreversible airflow obstruction. The response pattern of bronchodilators has not been followed in advanced lung function parameters. Purpose: The aim of this study was to investigate bronchodilator response pattern in advanced lung function parameters in a continuous fashion along forced expiratory volume in 1 second (FEV1 percent predicted (%p in COPD patients and controls. Patients and methods: Eighty-one smokers/ex-smokers (41 controls and 40 COPD performed spirometry, body plethysmography, impulse oscillometry and single-breath helium dilution carbon monoxide diffusion at baseline, after salbutamol inhalation and then after an additional inhalation of ipratropium. Results: Most pulmonary function parameters showed a linear increase in response to decreased FEV1%p. The subjects were divided into groups of FEV1%p <65 and >65, and the findings from continuous analysis were verified. The exceptions to this linear response were inspiratory capacity (IC, forced vital capacity (FVC, FEV1/FVC and expiratory resistance (Rex, which showed a segmented response relationship to FEV1%p. IC and FVC, with break points (BP of 57 and 58 FEV1%p respectively, showed no response above, but an incresed slope below the BP. In addition, in patients with FEV1%p <65 and >65, response of FEV1%p did not correlate to response of volume parameters. Conclusion: Response of several advanced lung function parameters differs depending on patients’ baseline FEV1%p, and specifically response of volume parameters is most pronounced in COPD patients with FEV1%p <65. Volume and resistance responses do not follow the flow response measured with FEV1 and may thus be used as a

  6. Functional link between DNA damage responses and transcriptional regulation by ATM in response to a histone deacetylase inhibitor TSA.

    Science.gov (United States)

    Lee, Jong-Soo

    2007-09-01

    Mutations in the ATM (ataxia-telangiectasia mutated) gene, which encodes a 370 kd protein with a kinase catalytic domain, predisposes people to cancers, and these mutations are also linked to ataxia-telangiectasia (A-T). The histone acetylaion/deacetylation- dependent chromatin remodeling can activate the ATM kinase-mediated DNA damage signal pathway (in an accompanying work, Lee, 2007). This has led us to study whether this modification can impinge on the ATM-mediated DNA damage response via transcriptional modulation in order to understand the function of ATM in the regulation of gene transcription. To identify the genes whose expression is regulated by ATM in response to histone deaceylase (HDAC) inhibition, we performed an analysis of oligonucleotide microarrays with using the appropriate cell lines, isogenic A-T (ATM(-)) and control (ATM(+)) cells, following treatment with a HDAC inhibitor TSA. Treatment with TSA reprograms the differential gene expression profile in response to HDAC inhibition in ATM(-) cells and ATM(+) cells. We analyzed the genes that are regulated by TSA in the ATM-dependent manner, and we classified these genes into different functional categories, including those involved in cell cycle/DNA replication, DNA repair, apoptosis, growth/differentiation, cell- cell adhesion, signal transduction, metabolism and transcription. We found that while some genes are regulated by TSA without regard to ATM, the patterns of gene regulation are differentially regulated in an ATM-dependent manner. Taken together, these finding indicate that ATM can regulate the transcription of genes that play critical roles in the molecular response to DNA damage, and this response is modulated through an altered HDAC inhibition-mediated gene expression.

  7. Transcription Factor Functional Protein-Protein Interactions in Plant Defense Responses

    Directory of Open Access Journals (Sweden)

    Murilo S. Alves

    2014-03-01

    Full Text Available Responses to biotic stress in plants lead to dramatic reprogramming of gene expression, favoring stress responses at the expense of normal cellular functions. Transcription factors are master regulators of gene expression at the transcriptional level, and controlling the activity of these factors alters the transcriptome of the plant, leading to metabolic and phenotypic changes in response to stress. The functional analysis of interactions between transcription factors and other proteins is very important for elucidating the role of these transcriptional regulators in different signaling cascades. In this review, we present an overview of protein-protein interactions for the six major families of transcription factors involved in plant defense: basic leucine zipper containing domain proteins (bZIP, amino-acid sequence WRKYGQK (WRKY, myelocytomatosis related proteins (MYC, myeloblastosis related proteins (MYB, APETALA2/ ETHYLENE-RESPONSIVE ELEMENT BINDING FACTORS (AP2/EREBP and no apical meristem (NAM, Arabidopsis transcription activation factor (ATAF, and cup-shaped cotyledon (CUC (NAC. We describe the interaction partners of these transcription factors as molecular responses during pathogen attack and the key components of signal transduction pathways that take place during plant defense responses. These interactions determine the activation or repression of response pathways and are crucial to understanding the regulatory networks that modulate plant defense responses.

  8. Contactless diagnostics of biophysical parameters of skin and blood on the basis of approximating functions for radiation fluxes scattered by skin

    Energy Technology Data Exchange (ETDEWEB)

    Lisenko, S A; Kugeiko, M M [Belarusian State University, Minsk (Belarus)

    2014-03-28

    Approximating expressions are derived to calculate spectral and spatial characteristics of diffuse reflection of light from a two-layer medium mimicking human skin. The effectiveness of the use of these expressions in the optical diagnosis of skin biophysical parameters (tissue scattering parameters, concentration of melanin in the epidermis, concentration of total haemoglobin and bilirubin in the tissues of the dermis) and content of haemoglobin derivatives in blood (oxy-, deoxy-, met-, carboxy- and sulfhaemoglobin) is analysed numerically. The methods are proposed to determine in realtime these parameters without contact of the measuring instrument with the patient's body. (biophotonics)

  9. Predator-dependent functional response in wolves: from food limitation to surplus killing.

    Science.gov (United States)

    Zimmermann, Barbara; Sand, Håkan; Wabakken, Petter; Liberg, Olof; Andreassen, Harry Peter

    2015-01-01

    The functional response of a predator describes the change in per capita kill rate to changes in prey density. This response can be influenced by predator densities, giving a predator-dependent functional response. In social carnivores which defend a territory, kill rates also depend on the individual energetic requirements of group members and their contribution to the kill rate. This study aims to provide empirical data for the functional response of wolves Canis lupus to the highly managed moose Alces alces population in Scandinavia. We explored prey and predator dependence, and how the functional response relates to the energetic requirements of wolf packs. Winter kill rates of GPS-collared wolves and densities of cervids were estimated for a total of 22 study periods in 15 wolf territories. The adult wolves were identified as the individuals responsible for providing kills to the wolf pack, while pups could be described as inept hunters. The predator-dependent, asymptotic functional response models (i.e. Hassell-Varley type II and Crowley-Martin) performed best among a set of 23 competing linear, asymptotic and sigmoid models. Small wolf packs acquired >3 times as much moose biomass as required to sustain their field metabolic rate (FMR), even at relatively low moose abundances. Large packs (6-9 wolves) acquired less biomass than required in territories with low moose abundance. We suggest the surplus killing by small packs is a result of an optimal foraging strategy to consume only the most nutritious parts of easy accessible prey while avoiding the risk of being detected by humans. Food limitation may have a stabilizing effect on pack size in wolves, as supported by the observed negative relationship between body weight of pups and pack size. © 2014 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

  10. Predicting invasive species impacts: a community module functional response approach reveals context dependencies.

    Science.gov (United States)

    Paterson, Rachel A; Dick, Jaimie T A; Pritchard, Daniel W; Ennis, Marilyn; Hatcher, Melanie J; Dunn, Alison M

    2015-03-01

    Predatory functional responses play integral roles in predator-prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species. Other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator-prey interactions and thus the predictive capability of the comparative functional response approach. We used a four-species community module (higher-order predator; focal native or invasive predators; parasites of focal predators; native prey) to compare the predatory functional responses of native Gammarus duebeni celticus and invasive Gammarus pulex amphipods towards three invertebrate prey species (Asellus aquaticus, Simulium spp., Baetis rhodani), thus, quantifying the context dependencies of parasitism and a higher-order fish predator on these functional responses. Our functional response experiments demonstrated that the invasive amphipod had a higher predatory impact (lower handling time) on two of three prey species, which reflects patterns of impact observed in the field. The community module also revealed that parasitism had context-dependent influences, for one prey species, with the potential to further reduce the predatory impact of the invasive amphipod or increase the predatory impact of the native amphipod in the presence of a higher-order fish predator. Partial consumption of prey was similar for both predators and occurred increasingly in the order A. aquaticus, Simulium spp. and B. rhodani. This was associated with increasing prey densities, but showed no context dependencies with parasitism or higher-order fish predator. This study supports the applicability of comparative functional responses as a tool to predict and assess invasive species impacts incorporating multiple context dependencies. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

  11. Investigating the ionosphere response to exhaust products of ``Progress'' cargo spacecraft engines on the basis of Irkutsk Incoherent Scatter Radar data

    Science.gov (United States)

    Shpynev, Boris; Alsatkin, Sergei; Khakhinov, Vitaliy; Lebedev, Valentin

    2017-04-01

    The FSUE Central Research Institute of Machine Building (TsNIIMash), Rocket and Space Corporation "Energia", and Institute of Solar-Terrestrial Physics of Siberian Branch of Russian Academy of Sciences (ISTP SB RAS) jointly conducted the active space experiment "Radar-Progress" in 2007-2015. During this experiment, we used the Irkutsk Incoherent Scatter Ra-dar to study space-time characteristics of ionospheric disturbances generated by exhaust products of "Progress" cargo spacecraft engines. As the basic effect during exhaust product injection we consider the formation of new centers for recombination of ambient ionospheric ions O+ on molecules of water and carbon dioxide. This produces an ionization "hole" in the region of injection. In nighttime conditions when the majority of experiments were performed, this hole was filled by hydrogen ions from the plasmasphere, thus the ion composition in the vicinity of the hole and incoherent scatter spectra were changed. For successful obser-vation of the ionization hole dynamics, the critical fac-tors are the degree of radar antenna diagram filling by exhaust products and the velocity of the thermospheric neutral wind, which makes exhaust gases move from the antenna diagram. These two factors lead to poor repeatability of successful experiments. Successful experiments recorded a decrease in electron density up to 35 % in the hole that existed for 30 min. The lifetime of the region with high concentration of H+ ions can be as long as one hour.

  12. Novel dictation and intraverbal responses as a function of a multiple exemplar instructional history.

    Science.gov (United States)

    Greer, R Douglas; Yaun, Lynn; Gautreaux, Grant

    2005-01-01

    We tested the effect of multiple exemplar instruction (MEI) on acquisition of joint spelling responses, vocal to written and vice versa, for three sets of five words by four kindergarteners with language delays using a delayed multiple probe design. First, students were taught to spell Set 1 as either vocal or written responses (two vocal and two written) and probed on untaught responses. Next students were taught Set 2 using MEI (i.e., alternating responses) and again probed untaught responses for Set 1. Finally, Set 3 was taught in a single response and students were probed on untaught responses. Two students spelled none of Set 1 untaught responses before MEI, while two spelled the words at 60% accuracy or 10% accuracy. After MEI on Set 2, all students spelled untaught responses for Set 1 at 80% to 100% accuracy and Set 3 at 80% to 100% accuracy. The MEI resulted in joint stimulus function such that formerly independent responses came under the same stimulus control. We replicated these results with four other kindergartners with autism who performed academically above their typically developing peers. The results are discussed in terms of Skinner's treatment of the independence of the two verbal operants.

  13. Acute stress potentiates brain response to milkshake as a function of body weight and chronic stress

    OpenAIRE

    Rudenga, KJ; Sinha, R.; Small, DM

    2012-01-01

    Objective Stress is associated with increased intake of palatable foods and with weight gain, particularly in overweight women. Stress, food, and body mass index (BMI) have been separately shown to impact amygdala activity. However, it is not known whether stress influences amygdala responses to palatable foods, and whether this response is associated with chronic stress or BMI. Design Fourteen overweight and obese women participated in a functional magnetic resonance imaging (fMRI) scan as t...

  14. Catecholamine responses to virtual combat: implications for post-traumatic stress and dimensions of functioning

    OpenAIRE

    Highland, Krista B.; Costanzo, Michelle E.; Jovanovic, Tanja; Norrholm, Seth D.; Ndiongue, Rochelle B.; Brian J. Reinhardt; Rothbaum, Barbara; Rizzo, Albert A.; Michael J Roy

    2015-01-01

    Posttraumatic stress disorder (PTSD) symptoms can result in functional impairment among service members (SMs), even in those without a clinical diagnosis. The variability in outcomes may be related to underlying catecholamine mechanisms. Individuals with PTSD tend to have elevated basal catecholamine levels, though less is known regarding catecholamine responses to trauma-related stimuli. We assessed whether catecholamine responses to a virtual combat environment impact the relationship betwe...

  15. Basilar-Membrane Responses to Broadband Noise Modeled Using Linear Filters With Rational Transfer Functions

    OpenAIRE

    Recio-Spinoso, Alberto; Fan, Yun-Hui; Ruggero, Mario A.

    2010-01-01

    Basilar-membrane responses to white Gaussian noise were recorded using laser velocimetry at basal sites of the chinchilla cochlea with characteristic frequencies near 10 kHz and first-order Wiener kernels were computed by cross correlation of the stimuli and the responses. The presence or absence of minimum-phase behavior was explored by fitting the kernels with discrete linear filters with rational transfer functions. Excellent fits to the kernels were obtained with filters with transfer fun...

  16. Functional Responses of Retaliatory Killing versus Recreational Sport Hunting of Leopards in South Africa.

    Directory of Open Access Journals (Sweden)

    Lourens H Swanepoel

    Full Text Available Predation strategies in response to altering prey abundances can dramatically influence the demographic effects of predation. Despite this, predation strategies of humans are rarely incorporated into quantitative assessments of the demographic impacts of humans killing carnivores. This scarcity largely seems to be caused by a lack of data. In this study, we contrasted predation strategies exhibited by people involved in retaliatory killing and recreational sport hunting of leopards (Panthera pardus in the Waterberg District Municipality, South Africa. We predicted a specialist predation strategy exemplified by a type II functional response for retaliatory killing, and a generalist strategy exemplified by a type III functional response for recreational sport hunting. We could not distinguish between a type I, a type II, or a type III functional response for retaliatory killing, but the most parsimonious model for recreational sport hunting corresponded to a type I functional response. Kill rates were consistently higher for retaliatory killing than for recreational sport hunting. Our results indicate that retaliatory killing of leopards may have severe demographic consequences for leopard populations, whereas the demographic consequences of recreational sport hunting likely are less dramatic.

  17. Functional Responses of Retaliatory Killing versus Recreational Sport Hunting of Leopards in South Africa.

    Science.gov (United States)

    Swanepoel, Lourens H; Somers, Michael J; Dalerum, Fredrik

    2015-01-01

    Predation strategies in response to altering prey abundances can dramatically influence the demographic effects of predation. Despite this, predation strategies of humans are rarely incorporated into quantitative assessments of the demographic impacts of humans killing carnivores. This scarcity largely seems to be caused by a lack of data. In this study, we contrasted predation strategies exhibited by people involved in retaliatory killing and recreational sport hunting of leopards (Panthera pardus) in the Waterberg District Municipality, South Africa. We predicted a specialist predation strategy exemplified by a type II functional response for retaliatory killing, and a generalist strategy exemplified by a type III functional response for recreational sport hunting. We could not distinguish between a type I, a type II, or a type III functional response for retaliatory killing, but the most parsimonious model for recreational sport hunting corresponded to a type I functional response. Kill rates were consistently higher for retaliatory killing than for recreational sport hunting. Our results indicate that retaliatory killing of leopards may have severe demographic consequences for leopard populations, whereas the demographic consequences of recreational sport hunting likely are less dramatic.

  18. Molecular response functions for the polarizable continuum model physical basis and quantum mechanical formalism

    CERN Document Server

    Cammi, Roberto

    2013-01-01

    This Brief presents the main aspects of the response functions theory (RFT) for molecular solutes described within the framework of the Polarizable Continuum Model (PCM). PCM is a solvation model for a Quantum Mechanical molecular system in which the solvent is represented as a continuum distribution of matter. Particular attention is devoted to the description of the basic features of the PCM model, and to the problems characterizing the study of the response function theory for molecules in solution with respect to the analogous theory on isolated molecules.

  19. Reverberation decay functions for narrow bands obtained from filtered time-windowed room impulse responses (L).

    Science.gov (United States)

    Mo, Fangshuo

    2015-06-01

    This study introduces a method to obtain the reverberation decay functions for narrow bands from the filtered time-windowed broadband room impulse responses. The method corresponds to the free decay process of the band-pass sound energy. The filtering process is independent of the band-pass filter phase responses and it reduces the filtering influence on the decay rates. It places no limit on the permissible product BT of the bandwidth B and the reverberation time T when evaluating the decay rates of the obtained decay functions.

  20. Time-Response Functions of Mechanical Networks with Inerters and Causality

    OpenAIRE

    Makris, Nicos

    2017-01-01

    This paper derives the causal time-response functions of three-parameter mechanical networks that have been reported in the literature and involve the inerter-a two-node element in which the force-output is proportional to the relative acceleration of its end-nodes. This two-terminal device is the mechanical analogue of the capacitor in a force-current/velocity-voltage analogy. The paper shows that all frequency-response functions that exhibit singularities along the real frequency axis need ...

  1. Response function and count rates with the SODART Bragg-Spectrometer

    DEFF Research Database (Denmark)

    Halm, I.; Wiebicke, H.J.; Christensen, Finn Erland

    1998-01-01

    The SODART X-ray telescope includes an Objective Crystal Spectrometer (OCS) providing an energy resolving power around 1000 by Bragg reflection upon crystals. The SODART-OCS response function is used within the XSPEC package for the calculation of count rates for X-ray line and continuum registra......The SODART X-ray telescope includes an Objective Crystal Spectrometer (OCS) providing an energy resolving power around 1000 by Bragg reflection upon crystals. The SODART-OCS response function is used within the XSPEC package for the calculation of count rates for X-ray line and continuum...

  2. Bias Errors due to Leakage Effects When Estimating Frequency Response Functions

    Directory of Open Access Journals (Sweden)

    Andreas Josefsson

    2012-01-01

    Full Text Available Frequency response functions are often utilized to characterize a system's dynamic response. For a wide range of engineering applications, it is desirable to determine frequency response functions for a system under stochastic excitation. In practice, the measurement data is contaminated by noise and some form of averaging is needed in order to obtain a consistent estimator. With Welch's method, the discrete Fourier transform is used and the data is segmented into smaller blocks so that averaging can be performed when estimating the spectrum. However, this segmentation introduces leakage effects. As a result, the estimated frequency response function suffers from both systematic (bias and random errors due to leakage. In this paper the bias error in the H1 and H2-estimate is studied and a new method is proposed to derive an approximate expression for the relative bias error at the resonance frequency with different window functions. The method is based on using a sum of real exponentials to describe the window's deterministic autocorrelation function. Simple expressions are derived for a rectangular window and a Hanning window. The theoretical expressions are verified with numerical simulations and a very good agreement is found between the results from the proposed bias expressions and the empirical results.

  3. Mouse neutrophils lacking lamin B-receptor expression exhibit aberrant development and lack critical functional responses.

    Science.gov (United States)

    Gaines, Peter; Tien, Chiung W; Olins, Ada L; Olins, Donald E; Shultz, Leonard D; Carney, Lisa; Berliner, Nancy

    2008-08-01

    The capacity of neutrophils to eradicate bacterial infections is dependent on normal development and activation of functional responses, which include chemotaxis and generation of oxygen radicals during the respiratory burst. A unique feature of the neutrophil is its highly lobulated nucleus, which is thought to facilitate chemotaxis, but may also play a role in other critical neutrophil functions. Nuclear lobulation is dependent on expression of the inner nuclear envelope protein, the lamin B receptor (LBR), mutations of which cause hypolobulated neutrophil nuclei in human Pelger-Huët anomaly and the "ichthyosis" (ic) phenotype in mice. In this study, we have investigated roles for LBR in mediating neutrophil development and activation of multiple neutrophil functions, including chemotaxis and the respiratory burst. A progenitor EML cell line was generated from an ic/ic mouse, and derived cells that lacked LBR expression were induced to mature neutrophils and then examined for abnormal morphology and functional responses. Neutrophils derived from EML-ic/ic cells exhibited nuclear hypolobulation identical to that observed in ichthyosis mice. The ic/ic neutrophils also displayed abnormal chemotaxis, supporting the notion that nuclear segmentation augments neutrophil extravasation. Furthermore, promyelocytic forms of ic/ic cells displayed decreased proliferative responses and produced a deficient respiratory burst upon terminal maturation. Our studies of promyelocytes that lack LBR expression have identified roles for LBR in regulating not only the morphologic maturation of the neutrophil nucleus, but also proliferative and functional responses that are critical to innate immunity.

  4. Functioning of peripheral Ia pathways in infants with typical development: responses in antagonist muscle pairs.

    Science.gov (United States)

    Teulier, Caroline; Ulrich, Beverly D; Martin, Bernard

    2011-02-01

    In muscle responses of proprioceptive origin, including the stretch/tendon reflex (T-reflex), the corresponding reciprocal excitation and irradiation to distant muscles have been described from newborn infants to older adults. However, the functioning of other responses mediated primarily by Ia-afferents has not been investigated in infants. Understanding the typical development of these multiple pathways is critical to determining potential problems in their development in populations affected by neurological disease, such as spina bifida or cerebral palsy. Hence, the goal of the present study was to quantify the excitability of Ia-mediated responses in lower limb muscles of infants with typical development. These responses were elicited by mechanical stimulation applied to the distal tendons of the gastrocnemius-soleus (GS), tibialis anterior (TA) and quadriceps (QAD) muscles of both legs in twelve 2- to 10-month-old infants and recorded simultaneously in antagonist muscle pairs by surface EMG. Tendon taps alone elicited responses in either, both or neither muscle. The homonymous response (T-reflex) was less frequent in the TA than the GS or QAD muscle. An 80 Hz vibration superimposed on tendon taps induced primarily an inhibition of monosynaptic responses; however, facilitation also occurred in either muscle of the recorded pair. These responses were not influenced significantly by age or gender. Vibration alone produced a tonic reflex response in the vibrated muscle (TVR) and/or the antagonist muscle (AVR). However, for the TA muscle the TVR was more frequently elicited in older than younger infants. High variability was common to all responses. Overall, the random distribution and inconsistency of muscle responses suggests that the gain of Ia-mediated feedback is unstable. We propose that during infancy the central nervous system needs to learn to set stable feedback gain, or destination of proprioceptive assistance, based on their use during functional

  5. Stimuli-Responsive Directional Vesicular Assembly with Tunable Surface Functionality and Impact on Enzyme Inhibition.

    Science.gov (United States)

    Sikder, Amrita; Ray, Debes; Aswal, Vinod K; Ghosh, Suhrit

    2017-08-08

    The article describes the self-assembly of a series of unsymmetrical bola-shaped π-amphiphiles (NDI-1, NDI-1a, NDI-2, NDI-3, and NDI-4) consisting of a hydrophobic naphthalene-diimide (NDI) chromophore attached to a nonionic hydrophilic wedge and an anionic headgroup in the two opposite arms of the central NDI. By design, only a single hydrazide group is linked either on the ionic or nonionic arm of the NDI. NDI-1 and NDI-1a are regioisomers differing only in the location of the hydrazide group, placed in the nonionic or ionic arm, respectively. NDI-2, NDI-3, and NDI-4 are similar to NDI-1 in the placement of the hydrazide group but differ in the nature of the ionic headgroups. Except for NDI-2, all of them exhibit spontaneous vesicle structures in water (pH 9.0) as established by electron microscopy, small-angle neutron scattering, dynamic light scattering, and spectroscopy studies. Supramolecularly assembled oligo-oxyethylene chains of the hydrophobic wedge exhibited a lower critical solution temperature (LCST) at ∼40 °C, similar to that of covalent polymers. Consequently, above the LCST, the bola-amphiphile was converted to a single headgroup surfactant, resulting in the collapse of the vesicular structure to nanoparticles. In all examples, the dominant H-bonding force among the hydrazide groups resulted in unidirectional orientation, leading to the formation of a nonsymmetric membrane with the H-bonded chain located at the inner wall. Therefore, the functional group displayed in these vesicles could be fully dictated by the location of the hydrazide group. Thus, for NDI-1, NDI-3, or NDI-4, the hydrazide group, located at the nonionic arm, directed the nonionic wedge to converge at the inner wall of the vesicle by displaying the anionic headgroups toward the outer surface. In contrast, NDI-1a formed a nonionic vesicle because in this case anionic headgroups were located at the inner wall of the membrane. Furthermore, among NDI-1, NDI-3, and NDI-4, the charge

  6. Magnetic field influences on the lateral dose response functions of photon-beam detectors: MC study of wall-less water-filled detectors with various densities.

    Science.gov (United States)

    Looe, Hui Khee; Delfs, Björn; Poppinga, Daniela; Harder, Dietrich; Poppe, Björn

    2017-06-21

    The distortion of detector reading profiles across photon beams in the presence of magnetic fields is a developing subject of clinical photon-beam dosimetry. The underlying modification by the Lorentz force of a detector's lateral dose response function-the convolution kernel transforming the true cross-beam dose profile in water into the detector reading profile-is here studied for the first time. The three basic convolution kernels, the photon fluence response function, the dose deposition kernel, and the lateral dose response function, of wall-less cylindrical detectors filled with water of low, normal and enhanced density are shown by Monte Carlo simulation to be distorted in the prevailing direction of the Lorentz force. The asymmetric shape changes of these convolution kernels in a water medium and in magnetic fields of up to 1.5 T are confined to the lower millimetre range, and they depend on the photon beam quality, the magnetic flux density and the detector's density. The impact of this distortion on detector reading profiles is demonstrated using a narrow photon beam profile. For clinical applications it appears as favourable that the magnetic flux density dependent distortion of the lateral dose response function, as far as secondary electron transport is concerned, vanishes in the case of water-equivalent detectors of normal water density. By means of secondary electron history backtracing, the spatial distribution of the photon interactions giving rise either directly to secondary electrons or to scattered photons further downstream producing secondary electrons which contribute to the detector's signal, and their lateral shift due to the Lorentz force is elucidated. Electron history backtracing also serves to illustrate the correct treatment of the influences of the Lorentz force in the EGSnrc Monte Carlo code applied in this study.

  7. Modified discrete particle model of optical scattering in skin tissue accounting for multiparticle scattering.

    Science.gov (United States)

    Schneiderheinze, Dirk H P; Hillman, Timothy R; Sampson, David D

    2007-11-12

    We rigorously account for the effects of multiparticle light scattering from a fractal sphere aggregate in order to simulate the optical properties of a soft biological tissue, human skin. Using a computational method that extends Mie theory to the multisphere case, we show that multiparticle scattering significantly affects the computed optical properties, resulting in a reduction in both scattering coefficient and anisotropy for the wavelengths simulated, as well as a significantly enhanced forward peak in the simulated phase function. The model is extended to incorporate the contribution of Rayleigh scatterers, which we show is required to obtain reasonable agreement with experimentally measured optical properties of skin tissue.

  8. Scattering matrix measurements and light-scattering calculations of calcite particles

    Directory of Open Access Journals (Sweden)

    D. D. Dabrowska

    2011-09-01

    Full Text Available We present measurements of the complete scattering matrix as a function of the scattering angle of a sample of calcite particles collected near Lecce, Italy. The measurements are done at a wavelength of 647 nm in the scattering angle range 3°−177°. FESEM and SEM images show that the sample consists largely of flake-like particles. Ten different flake-like geometries are randomly generated and their scattering properties are simulated with DDA for sizes from 0.1 μm to 1 μm. Some preliminary comparisons of the simulations and the measurements are shown.

  9. Determination of optical scattering properties of highly-scattering media in optical coherence tomography images

    DEFF Research Database (Denmark)

    Levitz, D.; Thrane, L.; Frosz, Michael Henoch

    2004-01-01

    We developed a new algorithm that fits optical coherence tomography (OCT) signals as a function of depth to a general theoretical OCT model which takes into account multiple scattering effects. With use of this algorithm, it was possible to extract both the scattering coefficient and anisotropy...

  10. Experimental design and multiple response optimization. Using the desirability function in analytical methods development.

    Science.gov (United States)

    Candioti, Luciana Vera; De Zan, María M; Cámara, María S; Goicoechea, Héctor C

    2014-06-01

    A review about the application of response surface methodology (RSM) when several responses have to be simultaneously optimized in the field of analytical methods development is presented. Several critical issues like response transformation, multiple response optimization and modeling with least squares and artificial neural networks are discussed. Most recent analytical applications are presented in the context of analytLaboratorio de Control de Calidad de Medicamentos (LCCM), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, C.C. 242, S3000ZAA Santa Fe, ArgentinaLaboratorio de Control de Calidad de Medicamentos (LCCM), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, C.C. 242, S3000ZAA Santa Fe, Argentinaical methods development, especially in multiple response optimization procedures using the desirability function. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Modeling Raman scattering in porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Miguel [Seccion de Estudios de Posgrado, ESIME-Culhuacan, IPN, Av. Santa Ana 1000, 04430, Mexico, D.F. (Mexico); Wang, Chumin [Instituto de Investigaciones en Materiales, UNAM, A.P. 70-360, 04510, Mexico, D.F. (Mexico)

    2005-06-01

    In this work, we model the Raman scattering by phonons using the Born potential and the Green's function formalism, which takes into account the long-range correlation of atomic vibrations. The porous silicon is viewed as a sponge, in which periodical column pores are dug in direction [001] from crystalline silicon, i.e., a supercell model is used to calculate the Raman response. The results show that the main Raman peak shifts to lower energies when the porosity increases, and for square pores it asymptotically approaches to a limit value of 475 cm{sup -1}. Finally, the supercell results are compared with the quantum wire model, in which the main Raman peaks move to higher energies as the width of the wires grows. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Antiproton-Proton Glory Scattering

    CERN Multimedia

    2002-01-01

    This experiment measures @*p and K|-p backwards scattering between 8 and 16 GeV/c in the Omega spectrometer using the S1 beam, with sensitivities of several events per nanobarn. The mechanism responsible for backward scattering in channels not mediated by particle exchange is not understood, and could be almost energy-independent glory scattering, especially since relatively high cross sections of 190~(@*p) and 120~(K|-p)nb have been measured earlier at 5~GeV/c. @p|-p backwards scattering is measured for monitoring purposes. The trigger requires a forward particle of momentum close to the beam momentum. Absence of light in the two forward Cerenkov counters indicates that the particle is a proton. Combinations of an incident @p|- and an outgoing K|+, or an incident K|- or @* and an outgoing @p|+, cover the following byproducts: @*p~@A~@p|+@p|- which is an (allowed) baryon exchange reaction, and the exotic exchange reactions @p|-p~@A~K|+Y K|-p~@A~@p|+Y|-, where Y|- may be the @S|- or the Y*|-(1385).

  13. Scattering anomaly in optics

    CERN Document Server

    Silveirinha, Mario G

    2016-01-01

    In time-reversal invariant electronic systems the scattering matrix is anti-symmetric. This property enables an effect, designated here as "scattering anomaly", such that the electron transport does not suffer from back reflections, independent of the specific geometry of the propagation path or the presence of time-reversal invariant defects. In contrast, for a generic time-reversal invariant photonic system the scattering matrix is symmetric and there is no similar anomaly. Here, it is theoretically proven that despite these fundamental differences there is a wide class of photonic platforms - in some cases formed only by time-reversal invariant media - in which the scattering anomaly can occur. It is shown that an optical system invariant under the action of the composition of the time-reversal, parity and duality operators is characterized by an anti-symmetric scattering matrix. Specific examples of photonic platforms wherein the scattering anomaly occurs are given, and it is demonstrated with full wave n...

  14. Scattering of Skyrmions

    Directory of Open Access Journals (Sweden)

    David Foster

    2015-08-01

    Full Text Available In this paper, we present a detailed study of Skyrmion–Skyrmion scattering for two B=1 Skyrmions in the attractive channel where we observe two different scattering regimes. For large separation, the scattering can be approximated as interacting dipoles. We give a qualitative estimate when this approximation breaks down. For small separations we observe an additional short-range repulsion which is qualitatively similar to monopole scattering. We also observe the interesting effect of “rotation without rotating” whereby two Skyrmions, whose orientations remain constant while well-separated, change their orientation after scattering. We can explain this effect by following preimages through the scattering process, thereby measuring which part of an in-coming Skyrmion forms part of an out-going Skyrmion. This leads to a new way of visualising Skyrmions. Furthermore, we consider spinning Skyrmions and find interesting trajectories.

  15. A Synergistic Approach of Desirability Functions and Metaheuristic Strategy to Solve Multiple Response Optimization Problems

    Science.gov (United States)

    Bera, Sasadhar; Mukherjee, Indrajit

    2010-10-01

    Ensuring quality of a product is rarely based on observations of a single quality characteristic. Generally, it is based on observations of family of properties, so-called `multiple responses'. These multiple responses are often interacting and are measured in variety of units. Due to presence of interaction(s), overall optimal conditions for all the responses rarely result from isolated optimal condition of individual response. Conventional optimization techniques, such as design of experiment, linear and nonlinear programmings are generally recommended for single response optimization problems. Applying any of these techniques for multiple response optimization problem may lead to unnecessary simplification of the real problem with several restrictive model assumptions. In addition, engineering judgements or subjective ways of decision making may play an important role to apply some of these conventional techniques. In this context, a synergistic approach of desirability functions and metaheuristic technique is a viable alternative to handle multiple response optimization problems. Metaheuristics, such as simulated annealing (SA) and particle swarm optimization (PSO), have shown immense success to solve various discrete and continuous single response optimization problems. Instigated by those successful applications, this chapter assesses the potential of a Nelder-Mead simplex-based SA (SIMSA) and PSO to resolve varied multiple response optimization problems. The computational results clearly indicate the superiority of PSO over SIMSA for the selected problems.

  16. Self-assembly of various Au nanocrystals on functionalized water-stable PVA/PEI nanofibers: a highly efficient surface-enhanced Raman scattering substrates with high density of "hot" spots.

    Science.gov (United States)

    Zhu, Han; Du, MingLiang; Zhang, Ming; Wang, Pan; Bao, ShiYong; Zou, Meiling; Fu, YaQin; Yao, JuMing

    2014-04-15

    We have demonstrated a facile approach for the fabrication of flexible and reliable sulfydryl functionalized PVA/PEI nanofibers with excellent water stability for the self-assembly of Au nanocrystals, such as Au nanoparticles (AuNPs), Au nanoflowers (AuNFs) and Au nanorods (AuNRs), used as the highly efficient surface-enhanced Raman scattering (SERS) substrates for the detection of rhodamine B (RhB). Various methods were employed to cross-link the PVA nanofibers with better morphology and porous structures after immersing in water for desired times. Various SERS-active Au nanocrystals, such as AuNPs, AuNFs, and AuNRs have been successfully synthesized. After the grafting of MPTES on the cross-linked PVA/PEI nanofibers, the Au nanocrystals can easily be self-assembled on the surfaces of the nanofibers because of the strong interactions of the Au-S chemical bondings. The Au nanocrystals self-assembled throughout the PVA/PEI nanofibers used as SERS substrates all exhibit enhanced SERS signals of RhB compared with their individual nanocrystals. It is mainly due to the close interparticle distance, mutual orientation and high density of "hot" spots, that can strongly affect the overall optical response and the SERS enhancement. By changing the amounts of the self-assembled AuNFs on the nanofibers, we can control the density of the "hot" spots. With the increased amounts of the AuNFs throughout the nanofibers, the SERS substrates show enhanced Raman signals of the RhB, indicating that the increased density of "hot" spots can directly lead to the SERS enhancement. The AuNFs/(PVA/PEI) SERS substrates show good sensitivity, reliability and low detection limit (10(-9) M). The presented approach can be broadly applicable to the assembly of different types of plasmonic nanostructures and these novel materials with strong SERS enhancement can be applied in bioanalysis and biosensors. © 2013 Published by Elsevier B.V.

  17. Elastic scattering phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Mackintosh, R.S. [The Open University, School of Physical Sciences, Milton Keynes (United Kingdom)

    2017-04-15

    We argue that, in many situations, fits to elastic scattering data that were historically, and frequently still are, considered ''good'', are not justifiably so describable. Information about the dynamics of nucleon-nucleus and nucleus-nucleus scattering is lost when elastic scattering phenomenology is insufficiently ambitious. It is argued that in many situations, an alternative approach is appropriate for the phenomenology of nuclear elastic scattering of nucleons and other light nuclei. The approach affords an appropriate means of evaluating folding models, one that fully exploits available empirical data. It is particularly applicable for nucleons and other light ions. (orig.)

  18. Assessing the item response theory with covariate (IRT-C) procedure for ascertaining differential item functioning

    NARCIS (Netherlands)

    Tay, L.; Vermunt, J.K.; Wang, C.

    2013-01-01

    We evaluate the item response theory with covariates (IRT-C) procedure for assessing differential item functioning (DIF) without preknowledge of anchor items (Tay, Newman, & Vermunt, 2011). This procedure begins with a fully constrained baseline model, and candidate items are tested for uniform

  19. THE FUNCTION OF SURFACTANT IS IMPAIRED DURING THE REIMPLANTATION RESPONSE IN RAT LUNG TRANSPLANTS

    NARCIS (Netherlands)

    ERASMUS, ME; PETERSEN, AH; OETOMO, SB; PROP, J

    1994-01-01

    In this study we investigated the surfactant function in rat lung transplants at the peak of the reimplantation response in experimental groups with increasing warm ischemic times of the lung transplant. The left and right lungs in five groups of rats were assessed 24 hours after left lung

  20. A transfer function approach to the small-signal response of saturated semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup; Blumenthal, D. J.; Mørk, Jesper

    2000-01-01

    A theoretical analysis of the small-signal frequency response (SSFR) of a wavelength converter based on cross-gain modulation in a semiconductor optical amplifier with a finite waveguide loss is presented. We use a transfer function formalism to explain the resonant behavior of the frequency...

  1. Effects of Sublethal Concentrations of Insecticides on the Functional Response of Two Mirid Generalist Predators.

    Directory of Open Access Journals (Sweden)

    Angeliki F Martinou

    Full Text Available The use of agrochemicals particularly pesticides, can hamper the effectiveness of natural enemies, causing disruption in the ecosystem service of biological control. In the current study, the effects of the insecticides thiacloprid and chlorantraniliprole on the functional response curves were assessed for two mirid predator nymphs, Macrolophus pygmaeus Rambur and Nesidiocoris tenuis Reuter. In the absence of insecticides, both predators exhibited a type II functional response when feeding on eggs of the moth Ephestia kuehniella. N. tenuis seems to be a more efficient predator than M. pygmaeus, as model estimated handling time was significantly lower for the former than for the latter. Residual exposure of M. pygmaeus to sublethal concentrations of either insecticide was associated with a change in the asymptote but not the type of the functional response curve. Thiacloprid seems to be the least compatible with M. pygmaeus, as it led to both a significant reduction of the attack rate and an increase in handling time. In contrast, chlorantraniliprole exposure significantly increased the handling time, but not the attack rate of the predator. Residual exposure of N. tenuis to sublethal concentrations of either insecticide did not have a significant effect on the type nor the parameters of the functional response model. The results show that pesticide residues that do not have lethal effects on beneficial arthropods can reduce prey consumption depending on predator species and on likely risks associated with toxicity.

  2. Foliar temperature-respiration response functions for broad-leaved tree species in the southern Appalachians.

    Science.gov (United States)

    Bolstad; Mitchell; Vose

    1999-11-01

    We measured leaf respiration in 18 eastern deciduous forest tree species to determine if there were differences in temperature-respiration response functions among species or among canopy positions. Leaf respiration rates were measured in situ and on detached branches for Acer pensylvanicum L., A. rubrum L., Betula spp. (B. alleghaniensis Britt. and B. lenta L.), Carya glabra (Mill.) Sweet, Cornus florida L., Fraxinus spp. (primarily F. americana L.), Liriodendron tulipifera L., Magnolia fraseri Walt., Nyssa sylvatica Marsh., Oxydendrum arboreum L., Platanus occidentalis L., Quercus alba L., Q. coccinea Muenchh., Q. prinus L., Q. rubra L., Rhododendron maximum L., Robinia psuedoacacia L., and Tilia americana L. in the southern Appalachian Mountains, USA. Dark respiration was measured on fully expanded leaves at 10, 15, 20, 25, and 30 degrees C with an infrared gas analyzer equipped with a temperature-controlled cuvette. Temperature-respiration response functions were fit for each leaf. There were significant differences in response functions among species and by canopy position within species. These differences were observed when respiration was expressed on a mass, nitrogen, or area basis. Cumulative nighttime leaf respiration was calculated and averaged over ten randomly selected nights for each leaf. Differences in mean cumulative nighttime respiration were statistically significant among canopy positions and species. We conclude that effects of canopy position and species on temperature-respiration response functions may need to be considered when making estimates of whole-tree or canopy respiration.

  3. The functional neuro-anatomy of the human response to fear

    African Journals Online (AJOL)

    sensory processing modulation.6 The response of the amygdala to threatening stimuli is probably modulated by a ... Mental Health, and Sensory Functions), Sant'Andrea. Hospital, Rome, Italy. M Pompili, MD, PhD ... of the anxiety disorders, facilitate their appropriate classification, and allow us to gauge the effects of their ...

  4. An Odds Ratio Approach for Assessing Differential Distractor Functioning Effects under the Nominal Response Model

    Science.gov (United States)

    Penfield, Randall D.

    2008-01-01

    Investigations of differential distractor functioning (DDF) can provide valuable information concerning the location and possible causes of measurement invariance within a multiple-choice item. In this article, I propose an odds ratio estimator of the DDF effect as modeled under the nominal response model. In addition, I propose a simultaneous…

  5. Glial cell response after aneurysmal subarachnoid hemorrhage - Functional consequences and clinical implications

    NARCIS (Netherlands)

    van Dijk, B.J.; Vergouwen, M.D.I.; Kelfkens, M.M.; Rinkel, G.J.E.; Hol, E.M.

    2016-01-01

    Glial cells, both astrocytes and microglia, respond to neurodegenerative processes and to brain damage by a process called reactive gliosis. This response is highly context dependent, varies from mild to severe, and can be protective or detrimental for neural functioning. In patients with a

  6. Basilar-membrane responses to broadband noise modeled using linear filters with rational transfer functions.

    Science.gov (United States)

    Recio-Spinoso, Alberto; Fan, Yun-Hui; Ruggero, Mario A

    2011-05-01

    Basilar-membrane responses to white Gaussian noise were recorded using laser velocimetry at basal sites of the chinchilla cochlea with characteristic frequencies near 10 kHz and first-order Wiener kernels were computed by cross correlation of the stimuli and the responses. The presence or absence of minimum-phase behavior was explored by fitting the kernels with discrete linear filters with rational transfer functions. Excellent fits to the kernels were obtained with filters with transfer functions including zeroes located outside the unit circle, implying nonminimum-phase behavior. These filters accurately predicted basilar-membrane responses to other noise stimuli presented at the same level as the stimulus for the kernel computation. Fits with all-pole and other minimum-phase discrete filters were inferior to fits with nonminimum-phase filters. Minimum-phase functions predicted from the amplitude functions of the Wiener kernels by Hilbert transforms were different from the measured phase curves. These results, which suggest that basilar-membrane responses do not have the minimum-phase property, challenge the validity of models of cochlear processing, which incorporate minimum-phase behavior. © 2011 IEEE

  7. Comparative responsiveness of measures of pain and function after total hip replacement

    DEFF Research Database (Denmark)

    Nilsdotter, A K; Roos, Ewa M.; Westerlund, J P

    2001-01-01

    To compare the responsiveness of the Functional Assessment System (FAS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Medical Outcomes Study 36-item Short Form (SF-36) in patients with osteoarthritis (OA) scheduled for total hip replacement....

  8. Testing Hypotheses about the Person-Response Function in Person-Fit Analysis

    Science.gov (United States)

    Emons, Wilco H. M.; Sijtsma, Klaas; Meijer, Rob R.

    2004-01-01

    The person-response function (PRF) relates the probability of an individual's correct answer to the difficulty of items measuring the same latent trait. Local deviations of the observed PRF from the expected PRF indicate person misfit. We discuss two new approaches to investigate person fit. The first approach uses kernel smoothing to estimate…

  9. Assessment of the biological control capability of Hippodamia variegata (Col.: Coccinellidae) using functional response experiments

    DEFF Research Database (Denmark)

    Madadi, Hossein; Parizi, Emad Mohajeri; Allahyari, Hossein

    2011-01-01

    Lady beetles are among the most successful predators of aphids in different environments. The functional responses of different life stages of Hippodamia variegata (Goeze) towards cotton aphidswere examined in two different set-ups, a two-dimensional Petri dish set-up with detached leaves and a t...

  10. A functional response model of a predator population foraging in a patchy habitat

    DEFF Research Database (Denmark)

    Nachman, Gösta

    2006-01-01

    1. Functional response models (e.g. Holling's disc equation) that do not take the spatial distributions of prey and predators into account are likely to produce biased estimates of predation rates. 2. To investigate the consequences of ignoring prey distribution and predator aggregation, a general...

  11. Functionality of the contralateral biceps femoris reflex response during human walking

    DEFF Research Database (Denmark)

    Stevenson, Andrew James Thomas; Geertsen, Svend S.; Sinkjær, Thomas

    2014-01-01

    In this study we examined the functionality of the contralateral biceps femoris (cBF) reflex response following ipsilateral knee extension joint rotations during the late stance phase of the gait cycle [1]. Stevenson et al. [1] proposed that the cBF reflex acts to slow the forward progression...

  12. Functional response of Cosmoclopius nigroannulatus (Hem.: Reduviidae to different densities of Spartocera dentiventris (Hem.: Coreidae nymphae

    Directory of Open Access Journals (Sweden)

    L. da Rocha

    Full Text Available This study evaluated the functional response of the predator Cosmoclopius nigroannulatus on first instar nymphae of Spartocera dentiventris, both species associated with Nicotina tabacum. The experiment was carried out in laboratory conditions: 27 ± 1ºC; 80 ± 5%, RH; 12 h, photophase. Ten newly emerged adults of each sex of C. nigroannulatus were used in each of five densities (5, 15, 25, 35, and 45 individuals of S. dentiventris nymphae. The predators were observed every 24 h for five days, when the number of dead and/or consumed nymphae was recorded. The results showed a positive correlation between the number of ingested nymphae and the increase in prey density. Females ingested more nymphae than the males. The estimated handling time per prey (Th was higher in males (3.07 h than in females (1.93 h, with total handling time (Th x Na increased with density. Other components of the functional response, such as attack rate (a', searching time (Ts, and search efficiency (E showed, in neither males nor females, a negative correlation regarding density. The results indicated a higher predatory efficiency in the females. The components of the functional response fitted significantly the randomic model of the Holling discs equation (Na = N {1 - exp[- a'(T - ThNa]}, evidencing a functional response of type II.

  13. The Effects of Fixed-Time Reinforcement Schedules on Functional Response Classes: A Translational Study

    Science.gov (United States)

    Heinicke, Megan R.; Carr, James E.; LeBlanc, Linda A.

    2012-01-01

    Research on functional response classes has applied significance because less severe forms of problem behavior have been found to co-occur with more severe forms. In addition, the most severe forms of problem behavior are sometimes targeted for intervention without monitoring other less severe forms. In such cases, it is unknown whether and how…

  14. Dysfunction of stress responsive systems as a risk factor for functional somatic syndromes

    NARCIS (Netherlands)

    Tak, Lineke M.; Rosmalen, Judith G. M.

    The etiology of functional somatic syndromes or disorders (FSDs) is generally considered to be a multifactorial interplay between psychological, biological, and social factors. One of the most investigated biological factors is stress responsive system dysfunction Despite more than twenty years of

  15. Response function for the characterization of photo-induced anisotropy in azobenzene containing polymers

    DEFF Research Database (Denmark)

    Sajti, S.; Kerekes, Á.; Ramanujam, P.S.

    2002-01-01

    A response function is derived for the description of photo-induced birefringence and dichroism in case of materials where the underlying process is photo-isomerization. Our result explains the usefulness of the theoretical formulae derived earlier by Kakichashvili for photo-anisotropic materials...

  16. Semi-Parametric Item Response Functions in the Context of Guessing. CRESST Report 844

    Science.gov (United States)

    Falk, Carl F.; Cai, Li

    2015-01-01

    We present a logistic function of a monotonic polynomial with a lower asymptote, allowing additional flexibility beyond the three-parameter logistic model. We develop a maximum marginal likelihood based approach to estimate the item parameters. The new item response model is demonstrated on math assessment data from a state, and a computationally…

  17. Reducing Escape Behavior and Increasing Task Completion with Functional Communication Training, Extinction, and Response Chaining.

    Science.gov (United States)

    Lalli, Joseph S.; And Others

    1995-01-01

    Functional communication training, extinction, and response chaining decreased escape-maintained aberrant behavior and increased task participation of 3 youth, ages 10 through 15, with moderate mental retardation, 2 of whom also had autism. Task escape was contingent on verbally responding and completing task steps. Behavior chaining also…

  18. Organization of Functional Postural Responses Following Perturbations in Multiple Directions in Elderly Fallers Standing Quietly

    Science.gov (United States)

    Matjacic, Zlatko; Sok, David; Jakovljevic, Miroljub; Cikajlo, Imre

    2013-01-01

    The objective of the study was to assess functional postural responses by analyzing the center-of-pressure trajectories resulting from perturbations delivered in multiple directions to elderly fallers. Ten elderly individuals were standing quietly on two force platforms while an apparatus delivered controlled perturbations at the level of pelvis…

  19. Response Reversal and Children with Psychopathic Tendencies: Success Is a Function of Salience of Contingency Change

    Science.gov (United States)

    Budhani, S.; Blair, R. J. R.

    2005-01-01

    Background: Previous work has inconsistently reported difficulties with response reversal/extinction in children with psychopathic tendencies. Method: We tested the hypothesis that the degree of impairment seen in children with psychopathic tendencies is a function of the salience of contingency change. We investigated the performance of children…

  20. Response inhibition and immediate arousal in children with high-functioning autism

    NARCIS (Netherlands)

    Raymaekers, Ruth; van der Meere, Jaap; Roeyers, Herbert

    The current study compared high-functioning children with autism (HFA) and a peer control group on an immediate arousal task measuring response inhibition. In one condition go stimuli were presented whereas in another condition a tone preceded the go stimulus. The tone caused an immediate arousal

  1. Proteomic insights into the functional basis for the response regulator DrRRA of Deinococcus radiodurans.

    Science.gov (United States)

    Wang, Liangyan; Hu, Jing; Liu, Mengjia; Yang, Su; Zhao, Ye; Cheng, Kaiying; Xu, Guangzhi; Li, Mingfeng; Tian, Bing; Hua, Yuejin

    2016-05-01

    Purpose To investigate the function basis of the recently discovered response regulator, drRRA (DNA damage response regulator A) in Deinococcus radiodurans, we compared the proteomic profile of the radiation-sensitive drRRA mutant with that of wild-type strain under both non-stress and gamma radiation treatment. Materials and methods Total proteins of D. radiodurans cells were subjected to two-dimension electrophoresis. Protein spots in 2-Dimension gels were silver stained and scanned. Spots that changed significantly in expression levels were selected for mass spectrometry analysis. Seven genes encoding representative proteins were knocked out for stress resistance analysis. Results A total of 52 proteins displayed significant expression level changes at least 1.5-fold in the mutant relative to wild-type strain under non-stress conditions, with 31 repressed and 21 induced proteins, which might affect the cell response of D. radiodurans to gamma radiation. The proteins were distributed into functional groups including stress response, metabolism, and function unknown. Disruptions of several altered proteins including DRA0259 (Catalase E) and DR1538 (Osmotically inducible protein C), reduced the antioxidant activity of D. radiodurans. Conclusion Combined with our previous result of transcriptional profile, we further confirmed that inactivation of DrRRA affects the expression of various stress response systems.

  2. Silicon Damage Response Function Derivation and Verification: Assessment of Impact on ASTM Standard E722

    Energy Technology Data Exchange (ETDEWEB)

    Depriest, Kendall [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-06-01

    Unsuccessful attempts by members of the radiation effects community to independently derive the Norgett-Robinson-Torrens (NRT) damage energy factors for silicon in ASTM standard E722-14 led to an investigation of the software coding and data that produced those damage energy factors. The ad hoc collaboration to discover the reason for lack of agreement revealed a coding error and resulted in a report documenting the methodology to produce the response function for the standard. The recommended changes in the NRT damage energy factors for silicon are shown to have significant impact for a narrow energy region of the 1-MeV(Si) equivalent fluence response function. However, when evaluating integral metrics over all neutrons energies in various spectra important to the SNL electronics testing community, the change in the response results in a small decrease in the total 1- MeV(Si) equivalent fluence of ~0.6% compared to the E722-14 response. Response functions based on the newly recommended NRT damage energy factors have been produced and are available for users of both the NuGET and MCNP codes.

  3. Stability and coherence of health experts' upper and lower subjective probabilities about dose-response functions.

    Science.gov (United States)

    Wallsten, T S; Forsyth, B H

    1983-06-01

    As part of a method for assessing health risks associated with primary National Ambient Air Quality Standards. T. B. Feagans and W. F. Biller (Research Triangle Park, North Carolina. EPA Office of Air Quality Planning and Standards, May 1981) developed a technique for encoding experts' subjective probabilities regarding dose--response functions. The encoding technique is based on B. O. Koopman's (Bulletin of the American Mathematical Society, 1940, 46, 763-764; Annals of Mathematics, 1940, 41, 269-292) probability theory, which does not require probabilities to be sharp, but rather allows lower and upper probabilities to be associated with an event. Uncertainty about a dose--response function can be expressed either in terms of the response rate expected at a given concentration or, conversely, in terms of the concentration expected to support a given response rate. Feagans and Biller (1981, cited above) derive the relation between the two conditional probabilities, which is easily extended to upper and lower conditional probabilities. These relations were treated as coherence requirements in an experiment utilizing four ozone and four lead experts as subjects, each providing judgments on two separate occasions. Four subjects strongly satisfied the coherence requirements in both conditions. and three more did no in the second session only. The eighth subject also improved in Session 2. Encoded probabilities were highly correlated between the two sessions, but changed from the first to the second in a manner that improved coherence and reflected greater attention to certain parameters of the dose--response function.

  4. Surface-enhanced Raman scattering from finite arrays of gold nano-patches

    Energy Technology Data Exchange (ETDEWEB)

    Vincenti, M. A.; Ceglia, D. de [AEgis Technologies Inc., 410 Jan Davis Dr, 35806 Huntsville, Alabama (United States); US Army-Charles M. Bowden Research Laboratory, 35898 Redstone Arsenal, Huntsville, Alabama (United States); Grande, M.; Petruzzelli, V.; D' Orazio, A. [Dipartimento di Elettrotecnica ed Elettronica, Politecnico di Bari, Via Re David 200, 70125 Bari (Italy); Bianco, G. V.; Bruno, G. [Inorganic Methodologies and of Plasmas, IMIP-CNR, via Orabona 4, 70126 Bari (Italy); Stomeo, T. [Center for Bio-Molecular Nanotechnology, Istituto Italiano di Technologia (IIT), Via Barsanti, 73010 Arnesano (Lecce) (Italy); De Vittorio, M. [Center for Bio-Molecular Nanotechnology, Istituto Italiano di Technologia (IIT), Via Barsanti, 73010 Arnesano (Lecce) (Italy); National Nanotechnology Laboratory (NNL), CNR-Istituto di Nanoscienze, Dip. Ingegneria dell' Innovazione, Universita Del Salento, Via Arnesano, 73100 Lecce (Italy); Scalora, M. [US Army-Charles M. Bowden Research Laboratory, 35898 Redstone Arsenal, Huntsville, Alabama (United States)

    2013-01-07

    We experimentally investigate the surface-enhanced Raman scattering (SERS) response of a 2D-periodic array of square gold nano-patches, functionalized by means of a conjugated, rigid thiol. We measure a Raman signal enhancement up to 200 times more intense compared to other plasmon-based nanostructures functionalized with the same molecule, and show that the enhancement is not strictly correlated to the presence of plasmonic resonances. The agreement between experimental and theoretical results reveals the importance of a full-wave analysis based on the inclusion of the actual scattering cross section of the molecule. The proposed numerical approach may serve not only as a tool to predict the enhancement of Raman signal scattered from strongly resonant nanostructure but also as an effective instrument to engineer SERS platforms that target specific molecules.

  5. The Moderating Role of Executive Functioning in Older Adults' Responses to a Reminder of Mortality

    Science.gov (United States)

    Maxfield, Molly; Pyszczynski, Tom; Greenberg, Jeff; Pepin, Renee; Davis, Hasker P.

    2011-01-01

    In previous research, older adults responded to mortality salience (MS) with increased tolerance, whereas younger persons responded with increased punitiveness. One possible explanation for this is that many older adults adapt to challenges of later life, such as the prospect of mortality, by becoming more flexible. Recent studies suggest that positively-oriented adaptation is more likely for older adults with high levels of executive functioning. We thus hypothesized that the better an older adult's executive functioning, the more likely MS would result in increased tolerance. Older and younger adults were randomly assigned to MS or control conditions, and then evaluated moral transgressors. As in previous research, younger adults were more punitive following reminders of mortality; executive functioning did not affect their responses. Among older adults, high functioning individuals responded to MS with increased tolerance rather than intolerance, whereas those low in functioning became more punitive. PMID:21728445

  6. Hermite scatterers in an ultraviolet sky

    Science.gov (United States)

    Parker, Kevin J.

    2017-12-01

    The scattering from spherical inhomogeneities has been a major historical topic in acoustics, optics, and electromagnetics and the phenomenon shapes our perception of the world including the blue sky. The long wavelength limit of ;Rayleigh scattering; is characterized by intensity proportional to k4 (or λ-4) where k is the wavenumber and λ is the wavelength. With the advance of nanotechnology, it is possible to produce scatterers that are inhomogeneous with material properties that are functions of radius r, such as concentric shells. We demonstrate that with proper choice of material properties linked to the Hermite polynomials in r, scatterers can have long wavelength scattering behavior of higher powers: k8, k16, and higher. These ;Hermite scatterers; could be useful in providing unique signatures (or colors) to regions where they are present. If suspended in air under white light, the back-scattered spectrum would be shifted from blue towards violet and then ultraviolet as the higher order Hermite scatterers were illuminated.

  7. The Uncertainty of Crop Yield Projections Is Reduced by Improved Temperature Response Functions

    Science.gov (United States)

    Wang, Enli; Martre, Pierre; Zhao, Zhigan; Ewert, Frank; Maiorano, Andrea; Rotter, Reimund P.; Kimball, Bruce A.; Ottman, Michael J.; White, Jeffrey W.; Reynolds, Matthew P.; hide

    2017-01-01

    Increasing the accuracy of crop productivity estimates is a key element in planning adaptation strategies to ensure global food security under climate change. Process-based crop models are effective means to project climate impact on crop yield, but have large uncertainty in yield simulations. Here, we show that variations in the mathematical functions currently used to simulate temperature responses of physiological processes in 29 wheat models account for is greater than 50% of uncertainty in simulated grain yields for mean growing season temperatures from 14 C to 33 C. We derived a set of new temperature response functions that when substituted in four wheat models reduced the error in grain yield simulations across seven global sites with different temperature regimes by 19% to 50% (42% average). We anticipate the improved temperature responses to be a key step to improve modelling of crops under rising temperature and climate change, leading to higher skill of crop yield projections.

  8. Manual of functions, assignments, and responsibilities for nuclear safety: Revision 2

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-15

    The FAR Manual is a convenient easy-to-use collection of the functions, assignments, and responsibilities (FARs) of DOE nuclear safety personnel. Current DOE directives, including Orders, Secretary of Energy Notices, and other assorted policy memoranda, are the source of this information and form the basis of the FAR Manual. Today, the majority of FARs for DOE personnel are contained in DOE`s nuclear safety Orders. As these Orders are converted to rules in the Code of Federal Regulations, the FAR Manual will become the sole source for information relating to the functions, assignments, responsibilities of DOE nuclear safety personnel. The FAR Manual identifies DOE directives that relate to nuclear safety and the specific DOE personnel who are responsible for implementing them. The manual includes only FARs that have been extracted from active directives that have been approved in accordance with the procedures contained in DOE Order 1321.1B.

  9. Anisotropic resonant scattering from polymer photonic crystals.

    Science.gov (United States)

    Haines, Andrew I; Finlayson, Chris E; Snoswell, David R E; Spahn, Peter; Hellmann, G Peter; Baumberg, Jeremy J

    2012-11-20

    Hyperspectral goniometry reveals anisotropic scattering which dominates the visual appearance of self-assembled polymer opals. The technique allows reconstruction of the reciprocal-space of nanostructures, and indicates that chain defects formed during shear-ordering are responsible for the anisotropy in these samples. Enhanced scattering with improving order is shown to arise from increased effective refractive index contrast, while broadband background scatter is suppressed by absorptive dopants. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Biological cell classification by multiangle light scattering

    Science.gov (United States)

    Salzman, G.C.; Crowell, J.M.; Mullaney, P.F.

    1975-06-03

    The specification is directed to an apparatus and method for detecting light scattering from a biological cell. Light, preferably from a coherent source of radiation, intercepts an individual biological cell in a stream of cells passing through the beam. Light scattered from the cell is detected at a selected number of angles between 0 and 90/sup 0/ to the longitudinal axis of the beam with a circular array of light responsive elements which produce signals representative of the intensity of light incident thereon. Signals from the elements are processed to determine the light-scattering pattern of the cell and therefrom its identity.

  11. Predictors of Nonhospitalization and Functional Response in Clozapine Treatment: A Nationwide, Population-Based Cohort Study.

    Science.gov (United States)

    Köhler-Forsberg, Ole; Horsdal, Henriette T; Legge, Sophie E; MacCabe, James H; Gasse, Christiane

    2017-04-01

    Clozapine remains the only evidence-based treatment for treatment-resistant schizophrenia, and prediction of clozapine response is important in developing stratified treatment. We studied potential predictors of clozapine response, applying functional assessments as well as service use. We performed a nationwide cohort study among all individuals diagnosed with schizophrenia in Denmark after 1995 (age, ≥18 years) who initiated clozapine treatment between 2004 and 2011 with a Global Assessment of Functioning (GAF-F) score registered at clozapine initiation. During up to 2-year follow-up, clinical response was defined as (a) no further hospitalization with schizophrenia or (b) improvement in GAF-F score (moderate improvement: increase, ≥10; substantial improvement: increase, ≥20; and GAF-F, ≥50). We performed Cox regression analysis and report adjusted hazard rate ratios (HRRs; 95% confidence intervals [95% CIs]). Among 502 clozapine users with a registered GAF-F score, 232 (46.2%) remained out of hospital, 96 (19.1%) achieved moderate functional improvement, and 29 (5.8%) substantial functional improvement. Of all potential predictors, voluntary status at clozapine initiation showed borderline statistical significance with nonhospitalization (HRR, 1.61; 95% CI, 0.97-2.67). Regarding functional improvement, living with a partner was the strongest predictor with an almost threefold increased HRR (2.78; 95% CI, 1.07-7.23). Female sex was only nonsignificantly associated with functional improvement, whereas the chance of substantial improvement decreased by 15% (HRR, 0.85; 95% CI, 0.72-1.00) for each year delay in clozapine initiation among females. Living with a partner was the strongest predictor of functioning after clozapine initiation in this study. Although potentially indicating better premorbid functioning, this finding stresses the need and importance of social support during the course of the treatment independent of clinical factors.

  12. Unfolded protein response (UPR) signaling regulates arsenic trioxide-mediated macrophage innate immune function disruption

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Ritesh K.; Li, Changzhao; Chaudhary, Sandeep C. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Ballestas, Mary E. [Department of Pediatrics Infectious Disease, Children' s of Alabama, School of Medicine, University of Alabama at Birmingham, AL (United States); Elmets, Craig A. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Robbins, David J. [Department of Surgery, Molecular Oncology Program, Miller School of Medicine, University of Miami, Miami (United States); Matalon, Sadis [Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL (United States); Deshane, Jessy S. [Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL (United States); Afaq, Farrukh [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Bickers, David R. [Department of Dermatology, Columbia University Medical Center, New York (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States)

    2013-11-01

    Arsenic exposure is known to disrupt innate immune functions in humans and in experimental animals. In this study, we provide a mechanism by which arsenic trioxide (ATO) disrupts macrophage functions. ATO treatment of murine macrophage cells diminished internalization of FITC-labeled latex beads, impaired clearance of phagocytosed fluorescent bacteria and reduced secretion of pro-inflammatory cytokines. These impairments in macrophage functions are associated with ATO-induced unfolded protein response (UPR) signaling pathway characterized by the enhancement in proteins such as GRP78, p-PERK, p-eIF2α, ATF4 and CHOP. The expression of these proteins is altered both at transcriptional and translational levels. Pretreatment with chemical chaperon, 4-phenylbutyric acid (PBA) attenuated the ATO-induced activation in UPR signaling and afforded protection against ATO-induced disruption of macrophage functions. This treatment also reduced ATO-mediated reactive oxygen species (ROS) generation. Interestingly, treatment with antioxidant N-acetylcysteine (NAC) prior to ATO exposure, not only reduced ROS production and UPR signaling but also improved macrophage functions. These data demonstrate that UPR signaling and ROS generation are interdependent and are involved in the arsenic-induced pathobiology of macrophage. These data also provide a novel strategy to block the ATO-dependent impairment in innate immune responses. - Highlights: • Inorganic arsenic to humans and experimental animals disrupt innate immune responses. • The mechanism underlying arsenic impaired macrophage functions involves UPR signaling. • Chemical chaperon attenuates arsenic-mediated macrophage function impairment. • Antioxidant, NAC blocks impairment in arsenic-treated macrophage functions.

  13. CO2-response function of radiation use efficiency in rice for climate change scenarios

    Directory of Open Access Journals (Sweden)

    Nereu Augusto Streck

    2012-07-01

    Full Text Available The objective of this work was to evaluate a generalized response function to the atmospheric CO2 concentration [f(CO2] by the radiation use efficiency (RUE in rice. Experimental data on RUE at different CO2 concentrations were collected from rice trials performed in several locations around the world. RUE data were then normalized, so that all RUE at current CO2 concentration were equal to 1. The response function was obtained by fitting normalized RUE versus CO2 concentration to a Morgan-Mercer-Flodin (MMF function, and by using Marquardt's method to estimate the model coefficients. Goodness of fit was measured by the standard deviation of the estimated coefficients, the coefficient of determination (R², and the root mean square error (RMSE. The f(CO2 describes a nonlinear sigmoidal response of RUE in rice, in function of the atmospheric CO2 concentration, which has an ecophysiological background, and, therefore, renders a robust function that can be easily coupled to rice simulation models, besides covering the range of CO2 emissions for the next generation of climate scenarios for the 21st century.

  14. Virtual Singular Scattering of Electromagnetic Waves in Transformation Media Concept

    Directory of Open Access Journals (Sweden)

    M. Y. Barabanenkov

    2012-07-01

    Full Text Available If a scatterer and an observation point (receive both approach the so-called near field zone of a source of electromagnetic waves, the scattering process becomes singular one which is mathematically attributed to the spatial singularity of the free space Green function at the origin. Starting from less well known property of left-handed material slab to transfer the singularity of the free space Green function by implementing coordinate transformation, we present a phenomenon of virtual singular scattering of electromagnetic wave on an inhomogeneity located in the volume of left – handed material slab. Virtual singular scattering means that a scatterer is situated only virtually in the near field zone of a source, being, in fact, positioned in the far field zone. Such a situation is realized if a scatterer is embedded into a flat Veselago’s lens and approaches the lens’s inner focus because a slab of Veselago medium produces virtual sources inside and behind the slab and virtual scatterer (as a source of secondary waves from both slab sides. Considering a line-like dielectric scatterer we demonstrate that the scattering efficiency is proportional to product of singular quasistatic parts of two empty space Green functions that means a multiplicative quasistatic singularity of the Green function for a slab of inhomogeneous Veselago medium. We calculate a resonance value of the scattering amplitude in the regime similar to the known Mie resonance scattering.

  15. Inclusive quasielastic scattering of polarized electrons from polarized nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Amaro, J.E. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Center for Theoretical Physics]|[Universidad de Granada (Spain). Dept. de Fisica Moderna]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Lab. for Nuclear Science]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics; Caballero, J.A. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia]|[Sevilla Univ. (Spain). Dept. de Fisica Atomica, Molecular y Nuclear; Donnelly, T.W. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Center for Theoretical Physics]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Lab. for Nuclear Science]|[Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics; Moya de Guerra, E. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia

    1996-12-23

    The inclusive quasielastic response functions that appear in the scattering of polarized electrons from polarized nuclei are computed and analyzed for several closed-shell-minus-one nuclei with special attention paid to {sup 39}K. Results are presented using two models for the ejected nucleon - when described by a distorted wave in the continuum shell model or by a plane wave in PWIA with on- and off-shell nucleons. Relativistic effects in kinematics and in the electromagnetic current have been incorporated throughout. Specifically, the recently obtained expansion of the electromagnetic current in powers only of the struck nucleon`s momentum is employed for the on-shell current and the effects of the first-order terms (spin-orbit and convection) are compared with the zeroth-order (charge and magnetization) contributions. The use of polarized inclusive quasielastic electron scattering as a tool for determining near-valence nucleon momentum distributions is discussed. (orig.).

  16. Differences in functional MR imaging activation patterns associated with confrontation naming and responsive naming.

    Science.gov (United States)

    Tomaszewki Farias, Sarah; Harrington, Gregory; Broomand, Catherine; Seyal, Maysud

    2005-01-01

    Direct cortical stimulation studies suggest that responsive naming is more widely distributed within the temporal lobe than confrontation naming and involves anterior temporal regions typically resected in a standard temporal lobectomy. The aim of the current study was to further demonstrate the anatomic dissociation between confrontation and responsive naming by using functional MR imaging (fMRI). Twenty participants underwent fMRI while performing either a confrontation or responsive naming task. Regions of interest were identified within the anterior and posterior temporal lobe. Responsive naming produced more activation than confrontation naming within the dominant temporal lobe, with activation extending into the temporal pole. Activation in the dominant temporal lobe associated with responsive naming was observed in the superior, middle, and inferior temporal gyri but was limited to the middle temporal gyrus for confrontation naming. Although both naming tasks produced activation within the posterior temporal region of interest in all participants, responsive and confrontation naming produced activation within the anterior temporal region of interest in 90% versus 60% of the sample, respectively. Areas of the dominant hemisphere activated by both tasks included parts of the middle occipital and middle temporal gyri, inferior frontal lobe, and hippocampus, among others. Findings are consistent with cortical stimulation studies and suggest that responsive naming produces more widespread activation within the temporal lobe compared with confrontation naming. The activation more often included anterior temporal regions during responsive naming as compared with confrontation naming. In clinical cases where the functional assessment of the temporal lobe-particularly the anterior regions-is important, the current results suggest responsive naming should be a useful fMRI paradigm and may ultimately help predict the risk of postsurgical language changes.

  17. Cardiac Nonmyocyte Cell Functions and Crosstalks in Response to Cardiotoxic Drugs

    Directory of Open Access Journals (Sweden)

    Jessica Gambardella

    2017-01-01

    Full Text Available The discovery of the molecular mechanisms involved in the cardiac responses to anticancer drugs represents the current goal of cardio-oncology research. The oxidative stress has a pivotal role in cardiotoxic responses, affecting the function of all types of cardiac cells, and their functional crosstalks. Generally, cardiomyocytes are the main target of research studies on cardiotoxicity, but recently the contribution of the other nonmyocyte cardiac cells is becoming of growing interest. This review deals with the role of oxidative stress, induced by anticancer drugs, in cardiac nonmyocyte cells (fibroblasts, vascular cells, and immune cells. The alterations of functional interplays among these cardiac cells are discussed, as well. These interesting recent findings increase the knowledge about cardiotoxicity and suggest new molecular targets for both diagnosis and therapy.

  18. Stability in a Simple Food Chain System with Michaelis-Menten Functional Response and Nonlocal Delays

    Directory of Open Access Journals (Sweden)

    Wenzhen Gan

    2013-01-01

    Full Text Available This paper is concerned with the asymptotical behavior of solutions to the reaction-diffusion system under homogeneous Neumann boundary condition. By taking food ingestion and species' moving into account, the model is further coupled with Michaelis-Menten type functional response and nonlocal delay. Sufficient conditions are derived for the global stability of the positive steady state and the semitrivial steady state of the proposed problem by using the Lyapunov functional. Our results show that intraspecific competition benefits the coexistence of prey and predator. Furthermore, the introduction of Michaelis-Menten type functional response positively affects the coexistence of prey and predator, and the nonlocal delay is harmless for stabilities of all nonnegative steady states of the system. Numerical simulations are carried out to illustrate the main results.

  19. Functional Response of Eretmocerus delhiensis on Trialeurodes vaporariorum by Parasitism and Host Feeding.

    Science.gov (United States)

    Ebrahimifar, Jafar; Jamshidnia, Arsalan; Allahyari, Hossein

    2017-01-01

    The parasitoid wasp, Eretmocerus delhiensis (Hymenoptera, Aphelinidae) is a thelytokous and syn-ovigenic parasitoid. To evaluate E. delhiensis as a biocontrol agent in greenhouse, the killing efficiency of this parasitoid by parasitism and host-feeding, were studied. Killing efficiency can be compared by estimation of functional response parameters. Laboratory experiments were performed in controllable conditions to evaluate the functional response of E. delhiensis at eight densities (2, 4, 8, 16, 32, 64, 100, and 120 third nymphal stage) of Trialeurodes vaporariorum (Hemiptera, Aleyrodidae) on two hosts including; tomato and prickly lettuce. The maximum likelihood estimates from regression logistic analysis revealed type II functional response for two host plants and the type of functional response was not affected by host plant. Roger's model was used to fit the data. The attack rate (a) for E. delhiensis was 0.0286 and 0.0144 per hour on tomato and 0.0434 and 0.0170 per hour on prickly lettuce for parasitism and host feeding, respectively. Furthermore, estimated handling times (Th) were 0.4911 and 1.4453 h on tomato and 0.5713 and 1.5001 h on prickly lettuce for parasitism and host feeding, respectively. Based on 95% confidence interval, functional response parameters were significantly different between the host plants solely in parasitism. Results of this study opens new insight in the host parasitoid interactions, subsequently needs further investigation before utilizing it for management and reduction of greenhouse whitefly. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

  20. Dual Function of NAC072 in ABF3-Mediated ABA-Responsive Gene Regulation in Arabidopsis.

    Science.gov (United States)

    Li, Xiaoyun; Li, Xiaoling; Li, Meijuan; Yan, Youcheng; Liu, Xu; Li, Ling

    2016-01-01

    The NAM, ATAF1/2, and CUC2 (NAC) domain proteins play various roles in plant growth and stress responses. Arabidopsis NAC transcription factor NAC072 has been reported as a transcriptional activator in Abscisic acid (ABA)-responsive gene expression. However, the exact function of NAC072 in ABA signaling is still elusive. In this study, we present evidence for the interrelation between NAC072 and ABA-responsive element binding factor 3 (ABF3) that act as a positive regulator of ABA-responsive gene expression in Arabidopsis. The transcript of NAC072 is up-regulated by ABF3 in ABA response, and NAC072 protein interacts with ABF3. Enhanced ABA sensitivity occurs in nac072 mutant plants that overexpressed ABF3. However, overexpression of NAC072 weakened the ABA sensitivity in the abf3 mutant plants, but instead of recovering the ABA sensitivity of abf3. NAC072 and ABF3 cooperate to regulate RD29A expression, but are antagonistic when regulating RD29B expression. Therefore, NAC072 displays a dual function in ABF3-mediated ABA-responsive gene regulation.