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Sample records for crossed andreev reflection

  1. Toy models of crossed Andreev reflection

    International Nuclear Information System (INIS)

    Melin, R; Jirari, H; Peysson, S

    2003-01-01

    We propose toy models of crossed Andreev reflection in multiterminal hybrid structures containing out-of-equilibrium conductors. We apply the description to two possible experiments: (i) to a device containing a large quantum dot inserted in a crossed Andreev reflection circuit, and (ii) to a device containing an Aharonov-Bohm loop inserted in a crossed Andreev reflection circuit

  2. Enhanced Andreev reflection in gapped graphene

    Science.gov (United States)

    Majidi, Leyla; Zareyan, Malek

    2012-08-01

    We theoretically demonstrate unusual features of superconducting proximity effect in gapped graphene that presents a pseudospin symmetry-broken ferromagnet with a net pseudomagnetization. We find that the presence of a band gap makes the Andreev conductance of graphene superconductor/pseudoferromagnet (S/PF) junction to behave similar to that of a graphene ferromagnet-superconductor junction. The energy gap ΔN can enhance the pseudospin inverted Andreev conductance of S/PF junction to reach a limiting maximum value for ΔN≫μ, which depending on the bias voltage can be larger than the value for the corresponding junction with no energy gap. We further demonstrate a damped-oscillatory behavior for the local density of states of the PF region of S/PF junction and a long-range crossed Andreev reflection process in PF/S/PF structure with antiparallel alignment of pseudomagnetizations of PFs, which confirm that, in this respect, the gapped normal graphene behaves like a ferromagnetic graphene.

  3. Andreev reflections and the quantum physics of black holes

    Science.gov (United States)

    Manikandan, Sreenath K.; Jordan, Andrew N.

    2017-12-01

    We establish an analogy between superconductor-metal interfaces and the quantum physics of a black hole, using the proximity effect. We show that the metal-superconductor interface can be thought of as an event horizon and Andreev reflection from the interface is analogous to the Hawking radiation in black holes. We describe quantum information transfer in Andreev reflection with a final state projection model similar to the Horowitz-Maldacena model for black hole evaporation. We also propose the Andreev reflection analogue of Hayden and Preskill's description of a black hole final state, where the black hole is described as an information mirror. The analogy between crossed Andreev reflections and Einstein-Rosen bridges is discussed: our proposal gives a precise mechanism for the apparent loss of quantum information in a black hole by the process of nonlocal Andreev reflection, transferring the quantum information through a wormhole and into another universe. Given these established connections, we conjecture that the final quantum state of a black hole is exactly the same as the ground state wave function of the superconductor/superfluid in the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity; in particular, the infalling matter and the infalling Hawking quanta, described in the Horowitz-Maldacena model, forms a Cooper pairlike singlet state inside the black hole. A black hole evaporating and shrinking in size can be thought of as the analogue of Andreev reflection by a hole where the superconductor loses a Cooper pair. Our model does not suffer from the black hole information problem since Andreev reflection is unitary. We also relate the thermodynamic properties of a black hole to that of a superconductor, and propose an experiment which can demonstrate the negative specific heat feature of black holes in a growing/evaporating condensate.

  4. Direct observation of ballistic Andreev reflection

    Science.gov (United States)

    Klapwijk, T. M.; Ryabchun, S. A.

    2014-12-01

    An overview is presented of experiments on ballistic electrical transport in inhomogeneous superconducting systems which are controlled by the process of Andreev reflection. The initial experiments based on the coexistence of a normal phase and a superconducting phase in the intermediate state led to the concept itself. It was followed by a focus on geometrically inhomogeneous systems like point contacts, which provided a very clear manifestation of the energy and direction dependence of the Andreev reflection process. The point contacts have recently evolved towards the atomic scale owing to the use of mechanical break-junctions, revealing a very detailed dependence of Andreev reflection on the macroscopic phase of the superconducting state. In present-day research, the superconducting in homogeneity is constructed by clean room technology and combines superconducting materials, for example, with low-dimensional materials and topological insulators. Alternatively, the superconductor is combined with nano-objects, such as graphene, carbon nanotubes, or semiconducting nanowires. Each of these "inhomogeneous systems" provides a very interesting range of properties, all rooted in some manifestation of Andreev reflection.

  5. Andreev reflection in monolayer MoS2

    Science.gov (United States)

    Majidi, Leyla; Rostami, Habib; Asgari, Reza

    2014-01-01

    Andreev reflection in a monolayer molybdenum disulfide superconducting-normal (S/N) hybrid junction is investigated. We find, by using a modified Dirac Hamiltonian and the scattering formalism, that the perfect Andreev reflection happens at normal incidence with p-doped S and N regions. The probability of the Andreev reflection and the resulting Andreev conductance, in this system, are demonstrated to be large in comparison with the corresponding gapped graphene structure. We further investigate the effect of a topological term (β ) in the Hamiltonian and show that it results in an enhancement of the Andreev conductance with p-doped S and N regions, while in the corresponding structure with an n-doped S region it is strongly reducible in comparison. This effect can be explained in terms of the dependence of the Andreev reflection probability on the sign of β and the chemical potential in the superconducting region.

  6. Andreev bound states. Some quasiclassical reflections

    International Nuclear Information System (INIS)

    Lin, Y.; Leggett, A. J.

    2014-01-01

    We discuss a very simple and essentially exactly solvable model problem which illustrates some nice features of Andreev bound states, namely, the trapping of a single Bogoliubov quasiparticle in a neutral s-wave BCS superfluid by a wide and shallow Zeeman trap. In the quasiclassical limit, the ground state is a doublet with a splitting which is proportional to the exponentially small amplitude for “normal” reflection by the edges of the trap. We comment briefly on a prima facie paradox concerning the continuity equation and conjecture a resolution to it

  7. Andreev bound states. Some quasiclassical reflections

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y., E-mail: yiriolin@illinois.edu; Leggett, A. J. [University of Illinois at Urhana-Champaign, Dept. of Physics (United States)

    2014-12-15

    We discuss a very simple and essentially exactly solvable model problem which illustrates some nice features of Andreev bound states, namely, the trapping of a single Bogoliubov quasiparticle in a neutral s-wave BCS superfluid by a wide and shallow Zeeman trap. In the quasiclassical limit, the ground state is a doublet with a splitting which is proportional to the exponentially small amplitude for “normal” reflection by the edges of the trap. We comment briefly on a prima facie paradox concerning the continuity equation and conjecture a resolution to it.

  8. Evidence for Crossed Andreev Reflections in (100)YBa2Cu3O7+δ-SrRuO3 superconductor-ferromagnet bilayers

    International Nuclear Information System (INIS)

    Asulin, I.; Yuli, O.; Millo, O.; Koren, G.

    2005-01-01

    Full Text:Since the ferromagnetic side of a superconductor-ferromagnet junction is spin polarized, Andreev reflections are suppressed. Consequently, the proximity induced superconductor order parameter in the ferromagnet is expected to decay rapidly, on the order of a nm, the typical coherence length in a ferromagnet. Our scanning tunneling spectroscopy measurements on thin epitaxial (100)YBa 2 Cu 3 O 7+ δ-SrRuO 3 (YBaCuO-SrO) bilayers, where SrO is a ferromagnet, indeed show that on most of the junction area the superconductor order parameter vanishes in the SrO layers thicker than 8 nm. However, we find localized regions, arranged along narrow (< 10 nm) stripes, where the order parameter (superconductor-like gap structure) penetrates the ferromagnet over more than 20 nm. This is attributed to 'Crossed Andreev Reflections,' taking place at domain boundaries, where an electron from one magnetic domain is retro reflected as a hole with opposite spin in an adjacent domain. Our observation may account for the (not abundant) cases where a long-range proximity effect was found in superconductor-ferromagnet proximity systems

  9. Signature of a Crossed Andreev Reflection effect (CARE) in YBaCuO/SrRuO3/YBaCuO junctions

    International Nuclear Information System (INIS)

    Aronov, P.; Gad Koren, G.

    2005-01-01

    Full Text:Magnetic properties of SFS and SF ramp-type junctions with Y Ba 2 Cu 3 O 7 -YBaCuO-δ electrodes (S), and the itinerant ferromagnet SrRuO 3 (SrO - F), were investigated. We looked for a crossed Andreev reflection effect (CARE) in which an electron from one magnetic domain in F is Andreev reflected as a hole into an adjacent, oppositely polarized, domain while a pair is transmitted into S. CARE is possible in SrO since the width of its domain walls is of the order of the YBaCuO coherence length (2-3nm). Our junctions behave as typical magnetic tunneling junctions, as the conductance spectra were always asymmetric, and a few showed bound state peaks at finite bias which shifted with field according to the classical Tedrow and Meservey theory. In many of our SFS junctions with a barrier thickness of 10-20nm, a prominent zero bias conductance peak (ZBCP) has been observed. This peak was found to decrease linearly with magnetic field, as expected for Andreev and CARE scattering. In contrast, in SF junctions, the observed ZBCP was found to decrease versus field almost exponentially, in agreement with the Anderson-Appelbaum theory of scattering by magnetic states in F. Thus, transport in our SFS and SF junctions depends strongly on the size of the F layer. We also found that in both cases, the ZBCP height at zero field decreased with increasing magnetic order of the domains in F, in agreement with the CARE mechanism

  10. Specular Andreev reflection in thin films of topological insulators

    Science.gov (United States)

    Majidi, Leyla; Asgari, Reza

    2016-05-01

    We theoretically reveal the possibility of specular Andreev reflection in a thin film topological insulator normal-superconductor (N/S) junction in the presence of a gate electric field. The probability of specular Andreev reflection increases with the electric field, and electron-hole conversion with unit efficiency happens in a wide experimentally accessible range of the electric field. We show that perfect specular Andreev reflection can occur for all angles of incidence with a particular excitation energy value. In addition, we find that the thermal conductance of the structure displays exponential dependence on the temperature. Our results reveal the potential of the proposed topological insulator thin-film-based N/S structure for the realization of intraband specular Andreev reflection.

  11. Andreev reflection properties in a parallel mesoscopic circuit with Majorana bound states

    Energy Technology Data Exchange (ETDEWEB)

    Mu, Jin-Tao; Han, Yu [Physics Department, Liaoning University, Shenyang 110036 (China); Gong, Wei-Jiang, E-mail: gwj@mail.neu.edu.cn [College of Sciences, Northeastern University, Shenyang 110819 (China)

    2017-03-15

    We investigate the Andreev reflection in a parallel mesoscopic circuit with Majorana bound states (MBSs). It is found that in such a structure, the Andreev current can be manipulated in a highly efficient way, by the adjustment of bias voltage, dot levels, inter-MBS coupling, and the applied magnetic flux. Besides, the dot-MBS coupling manner is an important factor to modulate the Andreev current, because it influences the period of the conductance oscillation. By discussing the underlying quantum interference mechanism, the Andreev-reflection property is explained in detail. We believe that all the results can assist to understand the nontrivial role of the MBSs in driving the Andreev reflection.

  12. Magnetoanisotropic spin-triplet Andreev reflection in ferromagnet-Ising superconductor junctions

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    Lv, Peng; Zhou, Yan-Feng; Yang, Ning-Xuan; Sun, Qing-Feng

    2018-04-01

    We theoretically study the electronic transport through a ferromagnet-Ising superconductor junction. A tight-binding Hamiltonian describing the Ising superconductor is presented. Then by combining the nonequilibrium Green's function method, the expressions of Andreev reflection coefficient and conductance are obtained. A strong magnetoanisotropic spin-triplet Andreev reflection is shown, and the magnetoanisotropic period is π instead of 2 π as in the conventional magnetoanisotropic system. We demonstrate a significant increase of the spin-triplet Andreev reflection for the single-band Ising superconductor. Furthermore, the dependence of the Andreev reflection on the incident energy and incident angle are also investigated. A complete Andreev reflection can occur when the incident energy is equal to the superconducting gap, regardless of the Fermi energy (spin polarization) of the ferromagnet. For the suitable oblique incidence, the spin-triplet Andreev reflection can be strongly enhanced. In addition, the conductance spectroscopies of both zero bias and finite bias are studied, and the influence of gate voltage, exchange energy, and spin-orbit coupling on the conductance spectroscopy are discussed in detail. The conductance exhibits a strong magnetoanisotropy with period π as the Andreev reflection coefficient. When the magnetization direction is parallel to the junction plane, a large conductance peak always emerges at the superconducting gap. This work offers a comprehensive and systematic study of the spin-triplet Andreev reflection and has an underlying application of π -periodic spin valve in spintronics.

  13. Transmission and Andreev reflection in one-dimensional chain with randomly doped superconducting grains

    International Nuclear Information System (INIS)

    Hu Dongsheng; Xiong Shijie

    2002-01-01

    We investigate the transport properties and Andreev reflection in one-dimensional (1D) systems with randomly doped superconducting grains. The superconducting grains are described by the Bogoliubov-de Gene Hamiltonian and the conductance is calculated by using the transfer matrix method and Landauer-Buettiker formula. It is found that although the quasiparticle states are localized due to the randomness and the low dimensionality, the conductance is still kept finite in the thermodynamical limit due to the Andreev reflection. We also investigate the effect of correlation of disorder in such systems and the results show the delocalization of quasiparticle states and suppression of Andreev reflection in a wide energy window

  14. Phase Coherence and Andreev Reflection in Topological Insulator Devices

    Directory of Open Access Journals (Sweden)

    A. D. K. Finck

    2014-11-01

    Full Text Available Topological insulators (TIs have attracted immense interest because they host helical surface states. Protected by time-reversal symmetry, they are robust to nonmagnetic disorder. When superconductivity is induced in these helical states, they are predicted to emulate p-wave pairing symmetry, with Majorana states bound to vortices. Majorana bound states possess non-Abelian exchange statistics that can be probed through interferometry. Here, we take a significant step towards Majorana interferometry by observing pronounced Fabry-Pérot oscillations in a TI sandwiched between a superconducting and a normal lead. For energies below the superconducting gap, we observe a doubling in the frequency of the oscillations, arising from an additional phase from Andreev reflection. When a magnetic field is applied perpendicular to the TI surface, a number of very sharp and gate-tunable conductance peaks appear at or near zero energy, which has consequences for interpreting spectroscopic probes of Majorana fermions. Our results demonstrate that TIs are a promising platform for exploring phase-coherent transport in a solid-state system.

  15. Specular Andreev reflection in graphene-based superconducting junction with substate-induced spin orbit interaction

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Chunxu, E-mail: chunxu_bai@semi.ac.cn [School of Physics, Anyang Normal University, Anyang 455000 (China); Yang, Yanling [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); School of Physics, Anyang Normal University, Anyang 455000 (China)

    2016-08-26

    Based on the Dirac–Bogoliubov–de Gennes equation, the chirality-resolved transport properties through a ballistic graphene-based superconducting heterojunction with both the Rashba and the Dresselhaus spin orbit interaction have been investigated. Our results show that, in contrast to the retro-Andreev reflection suppressed by the spin orbit interaction (SOI), the specular Andreev reflection (SAR) can be enhanced largely by the SOI. Moreover, the Fabry–Perot interferences in the barrier region lead to the oscillating feature of the tunneling conductance. It is anticipated to apply the qualitative different results to diagnose the SAR in single layer graphene in the presence of both kinds of the SOI. - Highlights: • The retro-Andreev reflection in graphene is suppressed by the spin orbit interaction. • The specular Andreev reflection in graphene can be enhanced largely by the spin orbit interaction. • The Fabry–Perot interferences in the graphene-based barrier lead to the oscillating feature of the tunneling conductance. • The spin orbit interaction is also vital in diagnosing the specular Andreev reflection in graphene.

  16. Specular Andreev reflection in graphene-based superconducting junction with substate-induced spin orbit interaction

    International Nuclear Information System (INIS)

    Bai, Chunxu; Yang, Yanling

    2016-01-01

    Based on the Dirac–Bogoliubov–de Gennes equation, the chirality-resolved transport properties through a ballistic graphene-based superconducting heterojunction with both the Rashba and the Dresselhaus spin orbit interaction have been investigated. Our results show that, in contrast to the retro-Andreev reflection suppressed by the spin orbit interaction (SOI), the specular Andreev reflection (SAR) can be enhanced largely by the SOI. Moreover, the Fabry–Perot interferences in the barrier region lead to the oscillating feature of the tunneling conductance. It is anticipated to apply the qualitative different results to diagnose the SAR in single layer graphene in the presence of both kinds of the SOI. - Highlights: • The retro-Andreev reflection in graphene is suppressed by the spin orbit interaction. • The specular Andreev reflection in graphene can be enhanced largely by the spin orbit interaction. • The Fabry–Perot interferences in the graphene-based barrier lead to the oscillating feature of the tunneling conductance. • The spin orbit interaction is also vital in diagnosing the specular Andreev reflection in graphene.

  17. Nonlocal Andreev reflection and spin current in a three-terminal Aharonov–Bohm interferometer

    International Nuclear Information System (INIS)

    Ju, Peng; Hua-Ling, Yu; Zhi-Guo, Wang

    2009-01-01

    This paper theoretically reports the nonlocal Andreev reflection and spin current in a normal metal-ferromagnetic metal-superconducting Aharonov–Bohm interferometer. It is found that the electronic current and spin current are sensitive to systematic parameters, such as the gate voltage of quantum dots and the external magnetic flux. The electronic current in the normal metal lead results from two competing processes: quasiparticle transmission and nonlocal Andreev reflection. The appearance of zero spin-up electronic current (or spin-down electronic current) signals the existence of nonlocal Andreev reflection, and the presence of zero electronic current results in the appearance of pure spin current. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  18. Proximity effect and Andreev reflection in single-C{sub 60} junctions

    Energy Technology Data Exchange (ETDEWEB)

    Brand, Jonathan; Neel, Nicolas; Kroeger, Joerg [Institut fuer Physik, Technische Universitaet Ilmenau, D-98693 Ilmenau (Germany)

    2016-07-01

    Single C{sub 60} molecules deposited on an ultrathin oxide film on Nb(110) were investigated using a low-temperature scanning tunnelling microscope. Spectroscopy of the differential conductance (dI/dV) in the tunnelling range indicates proximity-induced superconductivity in junctions comprising the oxide layer as well as single C{sub 60} molecules. Andreev reflection is enhanced upon controlled fabrication of tip-surface contacts. With decreasing electrode separation the Bardeen-Cooper-Schrieffer energy gap gradually evolves into a zero-bias peak in dI/dV spectra reflecting the spectroscopic signature of Andreev reflection. The current-voltage characteristics of the tunnelling and contact junctions are well described by the Blonder-Tinkham-Klapwijk theory. Our spectroscopic data evidence the influence of the electrodes' atomic-scale structure on electron transport across normal metal-superconductor interfaces.

  19. Manipulatable Andreev reflection due to the interplay between the DIII-class topological and s-wave superconductors

    Science.gov (United States)

    Wang, Xiao-Qi; Yi, Guang-Yu; Han, Yu; Jiang, Cui; Gong, Wei-Jiang

    2018-07-01

    We construct one mesoscopic circuit in which one quantum dot couples to one DIII-class topological superconductor and one s-wave superconductor, in addition to its connection with the metallic lead. And then, the Andreev reflection current in the metallic lead is evaluated. It is found that the two kinds of superconductors drive the Andreev reflection in the constructive manner. Next as finite superconducting phase difference is taken into account, the Andreev reflection oscillates in period π/2, and it can be suppressed in the low-energy region if the superconducting phase difference is (n + 1/2) π/2 (n ∈ Integer). Such a result is almost independent of the increase of the intradot Coulomb interaction. Therefore, this structure can assist to realize the manipulation of the Andreev reflection. Also, the result in this work provides useful information for understanding the property of the DIII-class topological superconductor.

  20. Superfluid {sup 3}He, a two-fluid system, with the normal-fluid dynamics dominated by Andreev reflection

    Energy Technology Data Exchange (ETDEWEB)

    Pickett, G. R., E-mail: g.pickett@lancaster.ac.uk [Lancaster University, Department of Physics (United Kingdom)

    2014-12-15

    As a specific offering towards his festschrift, we present a review the various properties of the excitation gas in superfluid {sup 3}He, which depend on Andreev reflection. This phenomenon dominates many of the properties of the normal fluid, especially at the lowest temperatures. We outline the ideas behind this dominance and describe a sample of the many experiments in this system which the operation of Andreev reflection has made possible, from temperature measurement, particle detection, vortex imaging to cosmological analogues.

  1. Full counting statistics of multiple Andreev reflections in incoherent diffusive superconducting junctions

    International Nuclear Information System (INIS)

    Samuelsson, P.

    2007-01-01

    We present a theory for the full distribution of current fluctuations in incoherent diffusive superconducting junctions, subjected to a voltage bias. This theory of full counting statistics of incoherent multiple Andreev reflections is valid for an arbitrary applied voltage. We present a detailed discussion of the properties of the first four cumulants as well as the low and high voltage regimes of the full counting statistics. (orig.)

  2. Andreev Reflection Spectroscopy of Nb-doped Bi2Se3 Topological Insulator

    Science.gov (United States)

    Kurter, C.; Finck, A. D. K.; Qiu, Y.; Huemiller, E.; Weis, A.; Atkinson, J.; Medvedeva, J.; Hor, Y. S.; van Harlingen, D. J.

    2015-03-01

    Doped topological insulators are speculated to realize p-wave superconductivity with unusual low energy quasiparticles, such as surface Andreev bound states. We present point contact spectroscopy of thin exfoliated flakes of Nb-doped Bi2Se3 where superconductivity persists up to ~ 1 K, compared to 3.2 K in bulk crystals. The critical magnetic field is strongly anisotropic, consistent with quasi-2D behavior. Andreev reflection measurements of devices with low resistance contacts result in prominent BTK-like behavior with an enhanced conductance plateau at low bias. For high resistance contacts, we observe a split zero bias conductance anomaly and additional features at the superconducting gap. Our results suggest that this material is a promising platform for studying topological superconductivity. We acknowledge support from Microsoft Project Q.

  3. Andreev spectrum with high spin-orbit interactions: Revealing spin splitting and topologically protected crossings

    Science.gov (United States)

    Murani, A.; Chepelianskii, A.; Guéron, S.; Bouchiat, H.

    2017-10-01

    In order to point out experimentally accessible signatures of spin-orbit interaction, we investigate numerically the Andreev spectrum of a multichannel mesoscopic quantum wire (N) with high spin-orbit interaction coupled to superconducting electrodes (S), contrasting topological and nontopological behaviors. In the nontopological case (square lattice with Rashba interactions), we find that the Kramers degeneracy of Andreev levels is lifted by a phase difference between the S reservoirs except at multiples of π , when the normal quantum wires can host several conduction channels. The level crossings at these points invariant by time-reversal symmetry are not lifted by disorder. Whereas the dc Josephson current is insensitive to these level crossings, the high-frequency admittance (susceptibility) at finite temperature reveals these level crossings and the lifting of their degeneracy at π by a small Zeeman field. We have also investigated the hexagonal lattice with intrinsic spin-orbit interaction in the range of parameters where it is a two-dimensional topological insulator with one-dimensional helical edges protected against disorder. Nontopological superconducting contacts can induce topological superconductivity in this system characterized by zero-energy level crossing of Andreev levels. Both Josephson current and finite-frequency admittance carry then very specific signatures at low temperature of this disorder-protected Andreev level crossing at π and zero energy.

  4. Unconventional Andreev reflection on the quasi-one-dimensional superconductor Nb2PdxSe5

    Directory of Open Access Journals (Sweden)

    Yeping Jiang

    2016-04-01

    Full Text Available We have carried out Andreev reflection measurements on point contact junctions between normal metal and single crystals of the quasi-one-dimensional (Q1D superconductor Nb2PdxSe5 (Tc ∼ 5.5 K. The contacts of the junctions were made on either self-cleaved surfaces or crystal edges so that the current flow directions in the two types of junctions are different, and the measurements provide a directional probe for the order parameter of the superconductor. Junctions made in both configurations show typical resistances of ∼20-30 Ohms, and a clear double-gap Andreev reflection feature was consistently observed at low temperatures. Quantitative analysis of the conductance spectrum based on a modified Blonder-Tinkham-Klapwijk (BTK model suggests that the amplitudes of two order parameters may have angular dependence in the a-c plane. Moreover, the gap to transition temperature ratio (Δ/TC for the larger gap is substantially higher than the BCS ratio expected for phonon-mediated s-wave superconductors. We argue that the anisotropic superconducting order parameter and the extremely large gap to transition temperature ratio may be associated with an unconventional pairing mechanism in the inorganic Q1D superconductor.

  5. Probing spin-polarized edge state superconductivity by Andreev reflection in in-plane magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Reinthaler, Rolf W.; Tkachov, Grigory; Hankiewicz, Ewelina M. [Faculty of Physics and Astrophysics, University of Wuerzburg, Wuerzburg (Germany)

    2015-07-01

    Finding signatures of unconventional superconductivity in Quantum Spin Hall systems is one of the challenges of solid state physics. Here we induce superconductivity in a 3D topological insulator thin film to cause the formation of helical edge states, which are protected against backscattering even in finite magnetic fields. Above a critical in-plane magnetic field, which is much smaller than the critical field of typical superconductors, the quasi-particle gap closes, giving rise to energy-dependent spin polarization. In this regime the spin-polarized edge state superconductivity can be detected by Andreev reflection. We propose measurement setups to experimentally observe the spin-dependent excess current and dI/dV characteristics.

  6. Theory of the Andreev reflection and the density of states in proximity contact normal-superconducting infinite double-layer

    International Nuclear Information System (INIS)

    Nagato, Yasushi; Nagai, Katsuhiko

    1993-01-01

    Proximity contact N-S double-layer with infinite layer widths is studied in the clean limit. The finite reflection at the interface is taken into account. Starting from a recent theory of finite width double-layer by Ashida et al., the authors obtain explicit expressions for the quasi-classical Green's function which already satisfy the boundary condition and include no exploding terms at infinities. The self-consistent pair potentials are obtained numerically with sufficient accuracy. The Andreev reflection at the N-S interface is discussed on the basis of the self-consistent pair potential. It is shown that there exists a resonance state in a potential valley formed between the depressed pair potential and the partially reflecting interface, which leads to a peak of the Andreev reflection coefficient with the height unity slightly below the bulk superconductor energy gap. They also find general relationship between the Andreev reflection coefficient and the local density of states of the superconductor just at the interface

  7. Direct observation of the Andreev reflection of a quasiparticle beam by quantum turbulence in superfluid 3He-B

    International Nuclear Information System (INIS)

    Bradley, D.I.; Fisher, S.N.; Guenault, A.M.; Lowe, M.R.; Pickett, G.R.; Rahm, A.

    2003-01-01

    A beam of quasiparticles from a black-body radiator is directed at a localized region of quantum turbulence generated by a vibrating wire resonator driven at super-critical velocity. We are able to measure directly the fraction of the incident quasiparticle beam which is retro-reflected from the turbulence by Andreev processes. Combining these measurements with previous measurements on the spatial extent of the turbulence may allow us to infer the vortex line density

  8. Gate-voltage control of equal-spin Andreev reflection in half-metal/semiconductor/superconductor junctions

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xiuqiang, E-mail: xianqiangzhe@126.com [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Meng, Hao, E-mail: menghao1982@shu.edu.cn [School of Physics and Telecommunication Engineering, Shanxi University of Technology, Hanzhong 723001 (China)

    2016-04-22

    With the Blonder–Tinkham–Klapwijk (BTK) approach, we investigate conductance spectrum in Ferromagnet/Semiconductor/Superconductor (FM/Sm/SC) double tunnel junctions where strong Rashba spin–orbit interaction (RSOI) is taken into account in semiconductors. For the half-metal limit, we find that the in-gap conductance becomes finite except at zero voltage when inserting a ferromagnetic insulator (FI) at the Sm/SC interface, which means that the appearance of a long-range triplet states in the half-metal. This is because of the emergence of the unconventional equal-spin Andreev reflection (ESAR). When the FI locates at the FM/Sm interface, however, we find the vanishing in-gap conductance due to the absence of the ESAR. Moreover, the non-zero in-gap conductance shows a nonmonotonic dependence on RSOI which can be controlled by applying an external gate voltage. Our results can be used to generate and manipulate the long-range spin triplet correlation in the nascent field of superconducting spintronics. - Highlights: • We study the equal-spin Andreev reflection in half-metal/semiconductor/superconductor (HM/Sm/SC) junctions. • The equal-spin Andreev reflection appearance when inserting a ferromagnetic insulator at the Sm/SC interface. • The finite in-gap conductance is attributed to the emergence of the equal-spin Andreev reflection. • The finite in-gap conductance shows a nonmonotonic dependence on Rashba spin–orbit interaction. • The finite in-gap conductance can be controlled by applying an external gate voltage.

  9. Supercurrent and multiple Andreev reflections in micrometer-long ballistic graphene Josephson junctions.

    Science.gov (United States)

    Zhu, Mengjian; Ben Shalom, Moshe; Mishchsenko, Artem; Fal'ko, Vladimir; Novoselov, Kostya; Geim, Andre

    2018-02-08

    Ballistic Josephson junctions are predicted to support a number of exotic physics processess, providing an ideal system to inject the supercurrent in the quantum Hall regime. Herein, we demonstrate electrical transport measurements on ballistic superconductor-graphene-superconductor junctions by contacting graphene to niobium with a junction length up to 1.5 μm. Hexagonal boron nitride encapsulation and one-dimensional edge contacts guarantee high-quality graphene Josephson junctions with a mean free path of several micrometers and record-low contact resistance. Transports in normal states including the observation of Fabry-Pérot oscillations and Sharvin resistance conclusively witness the ballistic propagation in the junctions. The critical current density J C is over one order of magnitude larger than that of the previously reported junctions. Away from the charge neutrality point, the I C R N product (I C is the critical current and R N the normal state resistance of junction) is nearly a constant, independent of carrier density n, which agrees well with the theory for ballistic Josephson junctions. Multiple Andreev reflections up to the third order are observed for the first time by measuring the differential resistance in the micrometer-long ballistic graphene Josephson junctions.

  10. Coulomb Blockade and Multiple Andreev Reflection in a Superconducting Single-Electron Transistor

    Science.gov (United States)

    Lorenz, Thomas; Sprenger, Susanne; Scheer, Elke

    2018-06-01

    In superconducting quantum point contacts, multiple Andreev reflection (MAR), which describes the coherent transport of m quasiparticles each carrying an electron charge with m≥3, sets in at voltage thresholds eV = 2Δ /m. In single-electron transistors, Coulomb blockade, however, suppresses the current at low voltage. The required voltage for charge transport increases with the square of the effective charge eV∝ ( me) ^2. Thus, studying the charge transport in all-superconducting single-electron transistors (SSETs) sets these two phenomena into competition. In this article, we present the fabrication as well as a measurement scheme and transport data for a SSET with one junction in which the transmission and thereby the MAR contributions can be continuously tuned. All regimes from weak to strong coupling are addressed. We extend the Orthodox theory by incorporating MAR processes to describe the observed data qualitatively. We detect a new transport process the nature of which is unclear at present. Furthermore, we observe a renormalization of the charging energy when approaching the strong coupling regime.

  11. Energy gap in MgB2 superconductor: Andreev reflection studies

    International Nuclear Information System (INIS)

    Aswal, D.K.

    2003-01-01

    To investigate the nature of energy gap in MgB 2 superconductor, we have performed Andreev-reflection studies on MgB 2 / Ag planar junctions. The differential resistance (dV/dI) versus voltage (V) characteristics were recorded as a function of temperature, magnetic field and junction-type. The dV/dI vs V characteristic recorded at low temperature and zero-field for a clean MgB 2 / Ag planar junction exhibited several interesting features, such as, zero bias anomaly, a distinct double-minima, sharp resonance peaks near the energy gap etc. The data, however, could not be explained using Blonder-Tinkham-Klapwijk theory of isotropic superconductor, which indicated that energy gap in MgB 2 is not consistent with the weak-coupling BCS theory. This is further supported by unusual temperature and magnetic field dependence of the tunneling characteristics. The results indicate several possibilities for the energy gap in MgB 2 , such as, an anisotropic energy gap, two-energy or an unconventional gap scenario. (author)

  12. Intradot spin-flip Andreev reflection tunneling through a ferromagnet-quantum dot-superconductor system with ac field

    International Nuclear Information System (INIS)

    Song Hongyan; Zhou Shiping

    2008-01-01

    We investigate Andreev reflection (AR) tunneling through a ferromagnet-quantum dot-superconductor (F-QD-S) system in the presence of an external ac field. The intradot spin-flip scattering in the QD is involved. Using the nonequilibrium Green function and BCS quasiparticle spectrum for superconductor, time-averaged AR conductance is formulated. The competition between the intradot spin-flip scattering and photon-assisted tunneling dominates the resonant behaviors of the time-averaged AR conductance. For weak intradot spin-flip scattering strengths, the AR conductance shows a series of equal interval resonant levels. However, the single-peak at main resonant level develops into a well-resolved double-peak resonance at a strong intradot spin-flip scattering strength. Remarkable, multiple-photon-assisted tunneling that generates photonic sideband peaks with a variable interval has been found. In addition, the AR conductance-bias voltage characteristic shows a transition between the single-peak to double-peak resonance as the ratio of the two tunneling strengths varies

  13. Two gap superconductivity in Ba0.55K0.45Fe2As2 single crystals studied by the directional point-contact Andreev reflection spectroscopy

    International Nuclear Information System (INIS)

    Szabo, P.; Pribulova, Z.; Pristas, G.; Bud'ko, S.L.; Canfield, P.C.; Samuely, P.

    2009-01-01

    First directional point-contact Andreev reflection spectroscopy on the Ba 0.55 K 0.45 Fe 2 As 2 single crystals is presented. The spectra show significant differences when measured in the ab plane in comparison with those measured in the c direction. In the latter case no traces of superconducting energy gap could be found, just a reduced point-contact conductance persisting up to about 100 K and indicating reduced density of states. On the other hand within the ab plane two nodeless superconducting energy gaps Δ S ∼2-5 meV and Δ L ∼9-11 meV are detected.

  14. Direct observation of hopping induced spin polarization current in oxygen deficient Co-doped ZnO by Andreev reflection technique

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Kung-Shang; Huang, Tzu-Yu; Dwivedi, G.D. [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Lin, Lu-Kuei; Lee, Shang-Fan [Taiwan Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Sun, Shih-Jye [Department of Applied Physics, National Kaohsiung University, Kaohsiung, Taiwan (China); Chou, Hsiung, E-mail: hchou@mail.nsysu.edu.tw [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China)

    2017-07-01

    Highlights: • Co-doped ZnO thin-films were grown with varying V{sub O} concentartion. • PCAR measurements were done to study the SPC. • High spin polarization was observed above a certain V{sub O} concentartion. • High V{sub O} samples provide a high density of completed percolation path. • This complete percolation path gives rise to high SPC. - Abstract: Oxygen vacancy induced ferromagnetic coupling in diluted magnetic oxide (DMO) semiconductors have been reported in several studies, but technologically more crucial spin-polarized current (SPC) is still under-developed in DMOs. Few studies have claimed that VRH mechanism can originate the SPC, but, how VRH mechanism associated with percolation path, is not clearly understood. We used Point-contact Andreev reflection (PCAR) technique to probe the SPC in Co-doped ZnO (CZO) films. Since the high resistance samples cause broadening in conductance(G)-voltage(V) curves, which may result in an unreliable evaluation of spin polarization, we include two extra parameters, (i) effective temperature and (ii) spreading resistance, for the simulation to avoid the uncertainty in extracting spin polarization. The effective G-V curves and higher spin polarization can be obtained above a certain oxygen vacancy concentration. The number of completed and fragmentary percolation paths is proportional to the concentration of oxygen vacancies. For low oxygen vacancy samples, the Pb-tip has a higher probability of covering fragmentary percolation paths than the complete ones, due to its small contact size. The completed paths may remain independent of one another and get polarized in different directions, resulting in lower spin-polarization value. High oxygen vacancy samples provide a high density of completed path, most of them link to one another by crossing over, and gives rise to high spin-polarization value.

  15. Energy gap and upper critical field of the new magnetic superconductor Mo3Sb7 found by the Andreev reflection method

    International Nuclear Information System (INIS)

    Dmitriev, V M; Rybaltchenko, L F; Ishchenko, L A; Khristenko, E V; Bukowski, Z; Troc, R

    2006-01-01

    We present the data of the point contact (PC) Andreev-reflection measurements on the new paramagnetic superconductor Mo 3 Sb 7 , which were used for finding the energy gap Δ and upper critical field H c2 for this compound. The maximum gap value, reduced to the zero temperature via the Bardeen-Cooper-Schrieffer (BCS) theory, turned out to be Δ (0) ≅ 0.32 meV, which is slightly smaller than that expected from the BCS theory, Δ BCS (0) ≅ 0.35 meV. The temperature dependence of the gap obeys the BCS theory approximately. The H c2 (0) value of about 16.5 kOe was obtained from fitting the experimental data to the conventional H(T) dependence, which is quadratic in temperature. This value is in close agreement with the result from magnetization measurements of 17.2 kOe

  16. Multigap superconductivity and strong electron-boson coupling in Fe-based superconductors: a point-contact Andreev-reflection study of Ba(Fe(1-x)Co(x))2As2 single crystals.

    Science.gov (United States)

    Tortello, M; Daghero, D; Ummarino, G A; Stepanov, V A; Jiang, J; Weiss, J D; Hellstrom, E E; Gonnelli, R S

    2010-12-03

    Directional point-contact Andreev-reflection measurements in Ba(Fe(1-x)Co(x))2As2 single crystals (T(c) = 24.5 K) indicate the presence of two superconducting gaps with no line nodes on the Fermi surface. The point-contact Andreev-reflection spectra also feature additional structures related to the electron-boson interaction, from which the characteristic boson energy Ω(b)(T) is obtained, very similar to the spin-resonance energy observed in neutron scattering experiments. Both the gaps and the additional structures can be reproduced within a three-band s ± Eliashberg model by using an electron-boson spectral function peaked at Ω(0) = 12 meV ≃ Ω(b)(0).

  17. Decay Lengths for Diffusive Transport Activated by Andreev Reflections in Al/n-GaAs/Al Superconductor-Semiconductor-Superconductor Junctions

    DEFF Research Database (Denmark)

    Kutchinsky, Jonatan; Taboryski, Rafael Jozef; Clausen, Thomas

    1997-01-01

    In a highly doped GaAs semiconductor with superconducting contacts of Al, clear conductance peaks are observed at zero voltage bias and at V = +/-2 Delta/e, +/-Delta/e. The subharmonic energy gap structure originates from Andreev scattering with diffusive, but energy conserving, transport in the ...

  18. What can Andreev bound states tell us about superconductors?

    Science.gov (United States)

    Millo, Oded; Koren, Gad

    2018-08-06

    Zero-energy Andreev bound states, which manifest themselves in the tunnelling spectra as zero-bias conductance peaks (ZBCPs), are abundant at interfaces between superconductors and other materials and on the nodal surface of high-temperature superconductors. In this review, we focus on the information such excitations can provide on the properties of superconductor systems. First, a general introduction to the physics of Andreev bound states in superconductor/normal metal interfaces is given with a particular emphasis on why they appear at zero energy in d -wave superconductors. Then, specific spectroscopic tunnelling studies of thin films, bilayers and junctions are described, focusing on the corresponding ZBCP features. Scanning tunnelling spectroscopy (STS) studies show that the ZBCPs on the c -axis YBa 2 Cu 3 O 7- δ (YBCO) films are correlated with the surface morphology and appear only in proximity to (110) facets. STS on c -axis La 1.88 Sr 0.12 CuO 4 (LSCO) films exhibiting the 1/8 anomaly shows spatially modulated peaks near zero bias associated with the anti-phase ordering of the d -wave order parameter predicted at this doping level. ZBCPs were also found in micrometre-size edge junctions of YBCO/SrRuO 3 /YBCO, where SrRuO 3 is ferromagnetic. Here, the results are consistent with a crossed Andreev reflection effect (CARE) at the narrow domain walls of the SrRuO 3 ZBCPs measured in STS studies of manganite/cuprate bilayers could not be attributed to CARE because the manganite's domain wall is much larger than the coherence length in YBCO, and instead are attributed to proximity-induced triplet-pairing superconductivity with non-conventional symmetry. And finally, ZBCPs found in junctions of non-intentionally doped topological insulator films of Bi 2 Se 3 and the s -wave superconductor NbN are attributed to proximity-induced p x  + ip y triplet order parameter in the topological material.This article is part of the theme issue 'Andreev bound states'.

  19. Angle dependence of Andreev scattering at semiconductor-superconductor interfaces

    DEFF Research Database (Denmark)

    Mortensen, Asger; Flensberg, Karsten; Jauho, Antti-Pekka

    1999-01-01

    We study the angle dependence of the Andreev scattering at a semiconductor-superconductor interface, generalizing the one-dimensional theory of Blonder, Tinkham, and Klapwijk (BTK),An increase of the momentum parallel to the interface leads to suppression of the probability of Andreev reflection...... and increase of the probability of normal reflection. We show that in the presence of a Fermi velocity mismatch between the semiconductor and the superconductor the angles of incidence and transmission are related according to the well-known Snell's law in optics. As a consequence there is a critical angle...

  20. Two gap superconductivity in Ba{sub 0.55}K{sub 0.45}Fe{sub 2}As{sub 2} single crystals studied by the directional point-contact Andreev reflection spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, P.; Pribulova, Z. [Centre of Low Temperature Physics, IEP Slovak Academy of Sciences and P.J.Safarik University, Watsonova 47, SK-04001 Kosice (Slovakia); Pristas, G.; Bud' ko, S.L.; Canfield, P.C. [Ames Laboratory and Iowa State University, Ames, IA 50011 (United States); Samuely, P., E-mail: samuely@saske.s [Centre of Low Temperature Physics, IEP Slovak Academy of Sciences and P.J.Safarik University, Watsonova 47, SK-04001 Kosice (Slovakia)

    2009-10-15

    First directional point-contact Andreev reflection spectroscopy on the Ba{sub 0.55}K{sub 0.45}Fe{sub 2}As{sub 2} single crystals is presented. The spectra show significant differences when measured in the ab plane in comparison with those measured in the c direction. In the latter case no traces of superconducting energy gap could be found, just a reduced point-contact conductance persisting up to about 100 K and indicating reduced density of states. On the other hand within the ab plane two nodeless superconducting energy gaps DELTA{sub S}approx2-5 meV and DELTA{sub L}approx9-11 meV are detected.

  1. Supercurrent Spectroscopy of Andreev States

    Directory of Open Access Journals (Sweden)

    L. Bretheau

    2013-12-01

    Full Text Available We measure the excitation spectrum of a superconducting atomic contact. In addition to the usual continuum above the superconducting gap, the single-particle excitation spectrum contains discrete, spin-degenerate Andreev levels inside the gap. Quasiparticle excitations are induced by a broadband on-chip microwave source and detected by measuring changes in the supercurrent flowing through the atomic contact. Since microwave photons excite quasiparticles in pairs, two types of transitions are observed: Andreev transitions, which consist of putting two quasiparticles in an Andreev level, and transitions to odd states with a single quasiparticle in an Andreev level and the other one in the continuum. In contrast to absorption spectroscopy, supercurrent spectroscopy allows detection of long-lived odd states.

  2. Fano effect and Andreev bound states in T-shape double quantum dots

    International Nuclear Information System (INIS)

    Calle, A.M.; Pacheco, M.; Orellana, P.A.

    2013-01-01

    In this Letter, we investigate the transport through a T-shaped double quantum dot coupled to two normal metal leads left and right and a superconducting lead. Analytical expressions of Andreev transmission and local density of states of the system at zero temperature have been obtained. We study the role of the superconducting lead in the quantum interferometric features of the double quantum dot. We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. Our results show that as a consequence of quantum interference and proximity effect, the transmission from normal to normal lead exhibits Fano resonances due to Andreev bound states. We find that this interference effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. - Highlights: • Transport properties of a double quantum dot coupled in T-shape configuration to conducting and superconducting leads are studied. • We report Fano antiresonances in the normal transmission due to the Andreev reflections in the superconducting lead. • We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. • Fano effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. • Andreev bound states survives even for strong dot-superconductor coupling

  3. Photon-assisted Andreev transport and sub-gap structures

    DEFF Research Database (Denmark)

    Wildt, M; Kutchinsky, Jonatan; Taboryski, Rafael Jozef

    2000-01-01

    We report new measurements of microwave-induced perturbations of the sub-harmonic energy gap structures in the current-voltage characteristics of superconductor-semiconductor-superconductor junctions. Around the sub-gap bias voltages associated with the enhanced quasi-particle transfer mediated...... by multiple Andreev reflection processes we observe microwave induced satellites, shifted in voltage by multiples of hf/en, where hf is the photon energy and n is the number of quasi-particle traversals as determined by the Andreev processes. The observed behavior is the analogue of the so-called photon...

  4. Quantum Dots and Andreev Reflections in Graphene

    NARCIS (Netherlands)

    Liu, X.L.

    2010-01-01

    Graphene is an exceptionally thin semiconductor that consists of only one atomic layer of carbon atoms. The electrons in graphene live in a strictly two-dimensional (2D) world. In addition to this remarkable 2Dness, it is also peculiar that the behavior of the electrons in graphene is governed by

  5. Using safety crosses for patient self-reflection.

    Science.gov (United States)

    Silverton, Sarah

    The Productive Mental Health Ward programme has been developed to improve efficiency and safety in the NHS. Patients in a medium-secure mental health unit used patient safety crosses as a tool for self-reflection as part of their recovery journey. This article describes how the project was set up as well as initial findings.

  6. Localized excitations in superconducting point contacts: probing the Andreev doublet

    International Nuclear Information System (INIS)

    Bretheau, L.

    2013-01-01

    The Josephson effect describes the coherent coupling between superconductors and the resulting supercurrent. Microscopically, it arises from the existence of discrete quasiparticle states, localized at the weak link, the Andreev bound states. They come in doublets in each conduction channel of the weak link, with energies symmetric about the Fermi energy and opposite supercurrents. Each Andreev doublet gives rise to four states: the ground state |-> and the excited state |+>, with even parity, and the excited odd states |↑> and |↓>. Is it possible to address and control Andreev doublets? This thesis describes two sets of experiments designed to answer this question using the most basic Josephson element, a one-atom contact between two superconducting electrodes. In a first experiment, we have observed and characterized the excited odd states |↑> and |↓>. As expected for a spin-degenerate system, they do not carry supercurrent. In this experiment the excitation was uncontrolled and resulted from trapping of spurious quasiparticles. We have measured the lifetime of the odd states: under some condition, it is found to exceed 100 μs. The second experiment is a photon-absorption spectroscopy of the Andreev doublet. It was performed by using a Josephson junction as an integrated on-chip microwave emitter and detector. The observed Andreev transitions correspond to excitation from the ground state |->to the excited even state |+>, and are well accounted for by our quantum model. This result opens the way to coherent manipulation of this two level system. The direct observation of the excited Andreev state, either by quasiparticle-injection or photon-absorption, strongly supports the mesoscopic theory of the Josephson effect. It shows that in addition to the phase difference, each channel of a Josephson weak link possesses an internal fermionic degree of freedom. It could be used to code information in a novel type of superconducting qubit. (author) [fr

  7. Fano-Andreev effect in Quantum Dots in Kondo regime

    Science.gov (United States)

    Orellana, Pedro; Calle, Ana Maria; Pacheco, Monica; Apel, Victor

    In the present work, we investigate the transport through a T-shaped double quantum dot system coupled to two normal leads and to a superconducting lead. We study the role of the superconducting lead in the quantum interferometric features of the double quantum dot and by means of a slave boson mean field approximation at low temperature regime. We inquire into the influence of intradot interactions in the electronic properties of the system as well. Our results show that Fano resonances due to Andreev bound states are exhibited in the transmission from normal to normal lead as a consequence of quantum interference and proximity effect. This Fano effect produced by Andreev bound states in a side quantum dot was called Fano-Andreev effect, which remains valid even if the electron-electron interaction are taken into account, that is, the Fano-Andreev effect is robust against e-e interactions even in Kondo regime. We acknowledge the financial support from FONDECYT program Grants No. 3140053 and 11400571.

  8. Probing Andreev bound states in one-atom superconducting contacts

    Energy Technology Data Exchange (ETDEWEB)

    Pothier, Hugues; Janvier, Camille; Tosi, Leandro; Girit, Caglar; Goffman, Marcelo; Esteve, Daniel; Urbina, Cristian [Quantronics Group, SPEC, CEA-Saclay (France)

    2015-07-01

    Superconductors are characterized by a dissipationless current. Since the work of Josephson 50 years ago, it is known that a supercurrent can even flow through tunnel junctions between superconductors. This Josephson effect also occurs through any type of ''weak links'' between superconductors: non-superconducting materials, constrictions,.. A unified understanding of the Josephson effect has emerged from a mesoscopic description of weak links. It relies on the existence of doublets of localized states that have energies below the superconducting gap: the Andreev bound states. I will present experiments performed on the simplest conductor possible, a single-atom contact between superconductors, that illustrate these concepts. The most recent work demonstrates time-domain manipulation of quantum superpositions of Andreev bound states.

  9. Andreev molecules in semiconductor nanowire double quantum dots.

    Science.gov (United States)

    Su, Zhaoen; Tacla, Alexandre B; Hocevar, Moïra; Car, Diana; Plissard, Sébastien R; Bakkers, Erik P A M; Daley, Andrew J; Pekker, David; Frolov, Sergey M

    2017-09-19

    Chains of quantum dots coupled to superconductors are promising for the realization of the Kitaev model of a topological superconductor. While individual superconducting quantum dots have been explored, control of longer chains requires understanding of interdot coupling. Here, double quantum dots are defined by gate voltages in indium antimonide nanowires. High transparency superconducting niobium titanium nitride contacts are made to each of the dots in order to induce superconductivity, as well as probe electron transport. Andreev bound states induced on each of dots hybridize to define Andreev molecular states. The evolution of these states is studied as a function of charge parity on the dots, and in magnetic field. The experiments are found in agreement with a numerical model.Quantum dots in a nanowire are one possible approach to creating a solid-state quantum simulator. Here, the authors demonstrate the coupling of electronic states in a double quantum dot to form Andreev molecule states; a potential building block for longer chains suitable for quantum simulation.

  10. Shooting quasiparticles from Andreev bound states in a superconducting constriction

    Energy Technology Data Exchange (ETDEWEB)

    Riwar, R.-P.; Houzet, M.; Meyer, J. S. [University of Grenoble Alpes, INAC-SPSMS (France); Nazarov, Y. V., E-mail: Y.V.Nazarov@tudelft.nl [Delft University of Technology, Kavli Institute of NanoScience (Netherlands)

    2014-12-15

    A few-channel superconducting constriction provides a set of discrete Andreev bound states that may be populated with quasiparticles. Motivated by recent experimental research, we study the processes in an a.c. driven constriction whereby a quasiparticle is promoted to the delocalized states outside the superconducting gap and flies away. We distinguish two processes of this kind. In the process of ionization, a quasiparticle present in the Andreev bound state is transferred to the delocalized states leaving the constriction. The refill process involves two quasiparticles: one flies away while another one appears in the Andreev bound state. We notice an interesting asymmetry of these processes. The electron-like quasiparticles are predominantly emitted to one side of the constriction while the hole-like ones are emitted to the other side. This produces a charge imbalance of accumulated quasiparticles, that is opposite on opposite sides of the junction. The imbalance may be detected with a tunnel contact to a normal metal lead.

  11. The effect of radioactive waste storage in Andreev Bay on contamination of the Barents Sea ecosystem

    Science.gov (United States)

    Matishov, G. G.; Ilyin, G. V.; Usyagina, I. S.; Moiseev, D. V.; Dahle, Salve; Kasatkina, N. E.; Valuyskaya, D. A.

    2017-02-01

    The effect of temporary radioactive waste storage on the ecological status of the sea and biota in the littoral of Andreev and Malaya Andreev bays and near the shore of Motovskii Gulf (including the mouth part of the Zapadnaya Litsa Bay) was analyzed. The littoral sediments contaminated by the 137Cs, 90Sr, 238Pu, and 239,240Pu isotopes are located in the zones of constant groundwater discharge on the shores of Andreev and Malaya Andreev bays. The littoral slopes and bottom depressions of the bays accumulate finely dispersed terrigenous material and 137Cs. The investigations have shown that the storage does not exert a significant adverse effect on the radioactive conditions and the status of the sea ecosystems beyond Andreev Bay.

  12. Reality, Dysconsciousness, and Transformations: Personal Reflections on the Ethics of Cross-Cultural Research

    Science.gov (United States)

    Janusch, Sandra

    2011-01-01

    In this personal narrative, I offer reflections about the process of conducting a cross-cultural, cross-linguistic research project with teachers of English in China. Lessons learned from this study address some of the hegemonic perspectives and assumptions that can be dysconsciously held by native English-speakers, the value of crossing borders…

  13. Effects of target shape and reflection on laser radar cross sections.

    Science.gov (United States)

    Steinvall, O

    2000-08-20

    Laser radar cross sections have been evaluated for a number of ideal targets such as cones, spheres, paraboloids, and cylinders by use of different reflection characteristics. The time-independent cross section is the ratio of the cross section of one of these forms to that of a plate with the same maximum radius. The time-dependent laser radar cross section involves the impulse response from the object shape multiplied by the beam's transverse profile and the surface bidirectional reflection distribution function. It can be clearly seen that knowledge of the combined effect of object shape and reflection characteristics is important for determining the shape and the magnitude of the laser radar return. The results of this study are of interest for many laser radar applications such as ranging, three-dimensional imaging-modeling, tracking, antisensor lasers, and target recognition.

  14. Andreev bound states probed in three-terminal quantum dots

    Science.gov (United States)

    Gramich, J.; Baumgartner, A.; Schönenberger, C.

    2017-11-01

    Andreev bound states (ABSs) are well-defined many-body quantum states that emerge from the hybridization of individual quantum dot (QD) states with a superconductor and exhibit very rich and fundamental phenomena. We demonstrate several electron transport phenomena mediated by ABSs that form on three-terminal carbon nanotube (CNT) QDs, with one superconducting (S) contact in the center and two adjacent normal-metal (N) contacts. Three-terminal spectroscopy allows us to identify the coupling to the N contacts as the origin of the Andreev resonance (AR) linewidths and to determine the critical coupling strengths to S, for which a ground state (or quantum phase) transition in such S-QD systems can occur. In addition, we ascribe replicas of the lowest-energy ABS resonance to transitions between the ABS and odd-parity excited QD states, a process we call excited state ABS resonances. In the conductance between the two N contacts we find a characteristic pattern of positive and negative differential subgap conductance, which we explain by considering two nonlocal processes, the creation of Cooper pairs in S by electrons from both N terminals, and a transport mechanism we call resonant ABS tunneling, possible only in multiterminal QD devices. In the latter process, electrons are transferred via the ABS without effectively creating Cooper pairs in S. The three-terminal geometry also allows spectroscopy experiments with different boundary conditions, for example by leaving S floating. Surprisingly, we find that, depending on the boundary conditions and the device parameters, the experiments either show single-particle Coulomb blockade resonances, ABS characteristics, or both in the same measurements, seemingly contradicting the notion of ABSs replacing the single-particle states as eigenstates of the QD. We qualitatively explain these results as originating from the finite time scale required for the coherent oscillations between the superposition states after a single

  15. Reduction of cross-polarized reflection to enhance dual-band absorption

    Science.gov (United States)

    Kundu, Debidas; Mohan, Akhilesh; Chakrabarty, Ajay

    2016-11-01

    In this paper, cross-polarized reflection from a periodic array of metal-dielectric-metal resonator units is reduced to improve its absorbing performance. Through this simple and typical example, it is shown that some reported absorbers are actually poor absorbers but efficient polarization converters, when the cross-polarized reflection is considered. Using a frequency selective surface, sandwiched between the top layer and the ground plane, the cross-polarized reflection is reduced by 7.2 dB at 5.672 GHz and 8.5 dB at 9.56 GHz, while negligibly affecting the co-polarized reflection reduction performance. The polarization conversion ratio is reduced from 90. 74% to 34.12% and 98.51% to 27.2% and total absorption is improved up to 80% from 26% and 21% around the two resonant frequencies. The reflection characteristics of the proposed absorber are quantitatively analyzed using interference theory, where the near field coupling of the resonant geometries and ground is taken into account. Measurement results show good agreement with both the numerically simulated and theoretical results.

  16. Current cross-correlations in double quantum dot Cooper pair splitter

    Energy Technology Data Exchange (ETDEWEB)

    Wrzesniewski, Kacper; Trocha, Piotr; Weymann, Ireneusz [Faculty of Physics, Adam Mickiewicz University, 61-614 Poznan (Poland)

    2016-07-01

    We investigate theoretically transport properties of a quantum dot (QD) system working as a Cooper pair splitter. The device is coupled to one superconducting and two ferromagnetic leads. Presented results are calculated using real-time diagrammatic technique in the sequential tunneling approximation with respect to the coupling to ferromagnetic leads. The transport properties are evaluated within the superconductor subgap regime taking into account Andreev reflection processes solely. We focus on the analysis of current and current cross-correlations, both in linear and nonlinear responses. Current cross-correlations give additional information about dynamics of transport processes. We identify both positive and negative signs of current cross-correlations and discuss mechanisms leading to those results. Strong negative cross-correlations are found when the occupation number of QD system becomes degenerate and near the emergence of the triplet blockade, while positive ones occur in the most range where current flows due to crossed Andreev processes. Finally, we consider ferromagnetic leads polarization and temperature influences on aforementioned features.

  17. Seismic reflection response from cross-correlations of ambient vibrations on non-conventional hidrocarbon reservoir

    Science.gov (United States)

    Huerta, F. V.; Granados, I.; Aguirre, J.; Carrera, R. Á.

    2017-12-01

    Nowadays, in hydrocarbon industry, there is a need to optimize and reduce exploration costs in the different types of reservoirs, motivating the community specialized in the search and development of alternative exploration geophysical methods. This study show the reflection response obtained from a shale gas / oil deposit through the method of seismic interferometry of ambient vibrations in combination with Wavelet analysis and conventional seismic reflection techniques (CMP & NMO). The method is to generate seismic responses from virtual sources through the process of cross-correlation of records of Ambient Seismic Vibrations (ASV), collected in different receivers. The seismic response obtained is interpreted as the response that would be measured in one of the receivers considering a virtual source in the other. The acquisition of ASV records was performed in northern of Mexico through semi-rectangular arrays of multi-component geophones with instrumental response of 10 Hz. The in-line distance between geophones was 40 m while in cross-line was 280 m, the sampling used during the data collection was 2 ms and the total duration of the records was 6 hours. The results show the reflection response of two lines in the in-line direction and two in the cross-line direction for which the continuity of coherent events have been identified and interpreted as reflectors. There is certainty that the events identified correspond to reflections because the time-frequency analysis performed with the Wavelet Transform has allowed to identify the frequency band in which there are body waves. On the other hand, the CMP and NMO techniques have allowed to emphasize and correct the reflection response obtained during the correlation processes in the frequency band of interest. The results of the processing and analysis of ASV records through the seismic interferometry method have allowed us to see interesting results in light of the cross-correlation process in combination with

  18. Giant Andreev backscattering and reentrant resistance in a 2- dimensional electron gas coupled to superconductors

    NARCIS (Netherlands)

    den Hartog, Sander; Wees, B.J. van; Nazarov, Yu.V.; Klapwijk, T.M.; Borghs, G.

    1998-01-01

    We have investigated the superconducting-phase modulated reduction in the resistance of a ballistic quantum point contact (QPC) connected via a disordered 2-dimensional electron gas (2DEG) to superconductors. We show that this reduction is caused by coherent Andreev back scattering of holes through

  19. Experimental analysis of bidirectional reflectance distribution function cross section conversion term in direction cosine space.

    Science.gov (United States)

    Butler, Samuel D; Nauyoks, Stephen E; Marciniak, Michael A

    2015-06-01

    Of the many classes of bidirectional reflectance distribution function (BRDF) models, two popular classes of models are the microfacet model and the linear systems diffraction model. The microfacet model has the benefit of speed and simplicity, as it uses geometric optics approximations, while linear systems theory uses a diffraction approach to compute the BRDF, at the expense of greater computational complexity. In this Letter, nongrazing BRDF measurements of rough and polished surface-reflecting materials at multiple incident angles are scaled by the microfacet cross section conversion term, but in the linear systems direction cosine space, resulting in great alignment of BRDF data at various incident angles in this space. This results in a predictive BRDF model for surface-reflecting materials at nongrazing angles, while avoiding some of the computational complexities in the linear systems diffraction model.

  20. Reflections

    Directory of Open Access Journals (Sweden)

    Joanne Embree

    2001-01-01

    Full Text Available Ideally, editorials are written one to two months before publication in the Journal. It was my turn to write this one. I had planned to write the first draft the evening after my clinic on Tuesday, September 11. It didn't get done that night or during the next week. Somehow, the topic that I had originally chosen just didn't seem that important anymore as I, along my friends and colleagues, reflected on the changes that the events of that day were likely to have on our lives.

  1. Student reflections on learning cross-cultural skills through a 'cultural competence' OSCE.

    Science.gov (United States)

    Miller, Elizabeth; Green, Alexander R

    2007-05-01

    Medical schools use OSCEs (objective structured clinical examinations) to assess students' clinical knowledge and skills, but the use of OSCEs in the teaching and assessment of cross-cultural care has not been well described. To examine medical students' reflections on a cultural competence OSCE station as an educational experience. Students at Harvard Medical School in Boston completed a 'cultural competence' OSCE station (about a patient with uncontrolled hypertension and medication non-adherence). Individual semi-structured interviews were conducted with a convenience sample of twenty-two second year medical students, which were recorded, transcribed, and analysed. Students' reflections on what they learned as the essence of the case encompassed three categories: (1) eliciting the patient's perspective on their illness; (2) examining how and why patients take their medications and inquiring about alternative therapies; and (3) exploring the range of social and cultural factors associated with medication non-adherence. A cultural competence OSCE station that focuses on eliciting patients' perspectives and exploring medication non-adherence can serve as a unique and valuable teaching tool. The cultural competence OSCE station may be one pedagogic method for incorporating cross-cultural care into medical school curricula.

  2. Gate-tunable Andreev bound states in InSb nanowire Josephson junction

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Ning; Li, Sen; Fan, Dingxun; Xu, Hongqi [Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871 (China); Caroff, Philippe [Division of Solid State Physics, Lund University, P. O. Box 118, S-221 00 Lund (Sweden)

    2016-07-01

    Hybrid InSb nanowire-superconductor devices are promising candidates for investigating Majorana modes in solid-state devices and future technologies of topological quantum manipulation. Here, we report low-temperature transport measurements on an individual InSb nanowire quantum dot coupled to superconducting contacts that exhibit an interplay between the Kondo effects and superconductivity. We observed two types of subgap resonance states within the superconducting gap, which can be attributed to gate-tunable Andreev bound states in Coulomb valleys with different Kondo temperatures. The presence of the gate-tunable 0 and pi junction allow us to investigate the fundamental 0- pi transition. Detailed magnetic field and temperature evolution of level spectroscopy demonstrate different behavior of two types of the Andreev bound states. Our results exhibit that the InSb nanowires can provide a promising platform for exploring phase coherence transport and the effect of spin-orbit coupling in semiconductor nanowire-superconductor hybrid device.

  3. Weyl nodes in Andreev spectra of multiterminal Josephson junctions: Chern numbers, conductances, and supercurrents

    Science.gov (United States)

    Xie, Hong-Yi; Vavilov, Maxim G.; Levchenko, Alex

    2018-02-01

    We consider mesoscopic four-terminal Josephson junctions and study emergent topological properties of the Andreev subgap bands. We use symmetry-constrained analysis for Wigner-Dyson classes of scattering matrices to derive band dispersions. When the scattering matrix of the normal region connecting superconducting leads is energy independent, the determinant formula for Andreev spectrum can be reduced to a palindromic equation that admits a complete analytical solution. Band topology manifests with an appearance of the Weyl nodes which serve as monopoles of finite Berry curvature. The corresponding fluxes are quantified by Chern numbers that translate into a quantized nonlocal conductance that we compute explicitly for the time-reversal-symmetric scattering matrix. The topological regime can also be identified by supercurrents as Josephson current-phase relationships exhibit pronounced nonanalytic behavior and discontinuities near Weyl points that can be controllably accessed in experiments.

  4. Relationship between reflection ability and clinical performance: a cross-sectional and retrospective-longitudinal correlational cohort study in midwifery.

    Science.gov (United States)

    Embo, M; Driessen, E; Valcke, M; van der Vleuten, C P M

    2015-01-01

    increasingly, reflection is highlighted as integral to core practice competencies but empirical research into the relationship between reflection and performance in the clinical workplace is scarce. this study investigated the relationship between reflection ability and clinical performance. we designed a cross-sectional and a retrospective-longitudinal cohort study. Data from first, second and third year midwifery students were collected to study the variables 'clinical performance' and 'reflection ability'. Data were analysed with SPSS for Windows, Release 20.0. Descriptive statistics, Pearson׳s Product Moment Correlation Coefficients (r) and r² values were computed to investigate associations between the research variables. the results showed a moderate observed correlation between reflection ability and clinical performance scores. When adopting a cross-sectional perspective, all correlation values were significant (p0.6). The results based on the retrospective-longitudinal data set explained a moderate proportion of the variance after correction for attenuation. Finally, the results indicate that 'reflection ability' scores of earlier years are significant related with 'clinical performance' scores of subsequent years. These results suggest that (1) reflection ability is linked to clinical performance; (2) that written reflections are an important, but not the sole way to assess professional competence and that (3) reflection is a contributor to clinical performance improvement. the data showed a moderate but significant relationship between 'reflection ability' and 'clinical performance' scores in clinical practice of midwifery students. Reflection therefore seems an important component of professional competence. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Understanding sunscreen SPF performance using cross-polarized UVA reflectance photography.

    Science.gov (United States)

    Crowther, J M

    2018-04-01

    Objective methods for understanding sunscreen behaviour in vitro before they are applied to the skin have failed to keep pace with the ever-increasing demands for higher SPF scores where the products are absorbing more and more similar levels of UV. A novel method for visualizing the spreading and location of SPF ingredients based on cross-polarized UVA reflectance photography is described here which gives new insights into the formation of final film morphology and how it correlates with in vivo SPF efficacy for a set of test products. High-resolution UVA-based images of sunscreen films spread onto PMMA plates were captured using a modified commercial SLR camera in a custom imaging system. Visual grading and image analysis were used to describe the overall UVA absorbance and streakiness of the resultant films, and the data compared with both in vivo and calculated in vitro SPF scores for the products. Differences were observed between the products in terms of how they spread during application. A strong correlation was observed between the evenness of the resultant film as determined from the photographs and final in vivo SPF scores. Cross-polarized UVA reflectance photography has been demonstrated to be a valuable new method for assessing sunscreen distribution after spreading and to differentiate product based on film morphology, as well as strongly correlating with final in vivo behaviour. © 2017 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  6. Multitemporal cross-calibration of the Terra MODIS and Landsat 7 ETM+ reflective solar bands

    Science.gov (United States)

    Angal, Amit; Xiong, Xiaoxiong; Wu, Aisheng; Chander, Gyanesh; Choi, Taeyoung

    2013-01-01

    In recent years, there has been a significant increase in the use of remotely sensed data to address global issues. With the open data policy, the data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Enhanced Thematic Mapper Plus (ETM+) sensors have become a critical component of numerous applications. These two sensors have been operational for more than a decade, providing a rich archive of multispectral imagery for analysis of mutitemporal remote sensing data. This paper focuses on evaluating the radiometric calibration agreement between MODIS and ETM+ using the near-simultaneous and cloud-free image pairs over an African pseudo-invariant calibration site, Libya 4. To account for the combined uncertainties in the top-of-atmosphere (TOA) reflectance due to surface and atmospheric bidirectional reflectance distribution function (BRDF), a semiempirical BRDF model was adopted to normalize the TOA reflectance to the same illumination and viewing geometry. In addition, the spectra from the Earth Observing-1 (EO-1) Hyperion were used to compute spectral corrections between the corresponding MODIS and ETM+ spectral bands. As EO-1 Hyperion scenes were not available for all MODIS and ETM+ data pairs, MODerate resolution atmospheric TRANsmission (MODTRAN) 5.0 simulations were also used to adjust for differences due to the presence or lack of absorption features in some of the bands. A MODIS split-window algorithm provides the atmospheric water vapor column abundance during the overpasses for the MODTRAN simulations. Additionally, the column atmospheric water vapor content during the overpass was retrieved using the MODIS precipitable water vapor product. After performing these adjustments, the radiometric cross-calibration of the two sensors was consistent to within 7%. Some drifts in the response of the bands are evident, with MODIS band 3 being the largest of about 6% over 10 years, a change that will be corrected in Collection 6 MODIS processing.

  7. Andreev reflections at interfaces between delta-doped GaAs and superconducting Al films

    DEFF Research Database (Denmark)

    Taboryski, Rafael Jozef; Clausen, Thomas; Hansen, Jørn Bindslev

    1996-01-01

    By placing several Si delta-doped layers close to the surface of a GaAs molecular beam epitaxy-grown crystal, we achieve a compensation of the Schottky barrier and obtain a good Ohmic contact between an in situ deposited (without breaking the vacuum) Al metallization layer and a highly modulation...

  8. Principles of femtosecond X-ray/optical cross-correlation with X-ray induced transient optical reflectivity in solids

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, S., E-mail: sebastian.eckert@helmholtz-berlin.de, E-mail: martin.beye@helmholtz-berlin.de; Beye, M., E-mail: sebastian.eckert@helmholtz-berlin.de, E-mail: martin.beye@helmholtz-berlin.de; Pietzsch, A.; Quevedo, W.; Hantschmann, M. [Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Ochmann, M.; Huse, N. [Institute for Nanostructure and Solid State Physics, University of Hamburg, Jungiusstr. 11, 20355 Hamburg, Germany and Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg (Germany); Ross, M.; Khalil, M. [Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195 (United States); Minitti, M. P.; Turner, J. J.; Moeller, S. P.; Schlotter, W. F.; Dakovski, G. L. [LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Föhlisch, A. [Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam (Germany)

    2015-02-09

    The discovery of ultrafast X-ray induced optical reflectivity changes enabled the development of X-ray/optical cross correlation techniques at X-ray free electron lasers worldwide. We have now linked through experiment and theory the fundamental excitation and relaxation steps with the transient optical properties in finite solid samples. Therefore, we gain a thorough interpretation and an optimized detection scheme of X-ray induced changes to the refractive index and the X-ray/optical cross correlation response.

  9. Andreev Bound States Formation and Quasiparticle Trapping in Quench Dynamics Revealed by Time-Dependent Counting Statistics.

    Science.gov (United States)

    Souto, R Seoane; Martín-Rodero, A; Yeyati, A Levy

    2016-12-23

    We analyze the quantum quench dynamics in the formation of a phase-biased superconducting nanojunction. We find that in the absence of an external relaxation mechanism and for very general conditions the system gets trapped in a metastable state, corresponding to a nonequilibrium population of the Andreev bound states. The use of the time-dependent full counting statistics analysis allows us to extract information on the asymptotic population of even and odd many-body states, demonstrating that a universal behavior, dependent only on the Andreev state energy, is reached in the quantum point contact limit. These results shed light on recent experimental observations on quasiparticle trapping in superconducting atomic contacts.

  10. Reflections on Online Learning Designs and Cross-Institutional Research Collaborations: Revisiting "Classrooms without Walls" in Two Australian Universities

    Science.gov (United States)

    Rossi, Dolene; van Rensburg, Henriette; Clark, Damien; Harreveld, R. E.; Beer, Colin; Danaher, P. A.

    2015-01-01

    The article on which this paper reflects ["Exploring a Cross-Institutional Research Collaboration and Innovation: Deploying Social Software and Web 2.0 Technologies to Investigate Online Learning Designs and Interactions in Two Australian Universities"] presented elements of a research project investigating learning interactions in…

  11. Deep Interior: Radio Reflection Tomographic Imaging of Earth-Crossing Asteroids

    Science.gov (United States)

    Asphaug, E.; Belton, M.; Safaeinili, A.; Klaasen, K.; Ostro, S.; Yeomans, D.; Plaut, J.

    2004-12-01

    Near-Earth Objects (NEOs) present an important scientific question and an intriguing space hazard. They are scrutinized by a number of large, dedicated groundbased telescopes, and their diverse compositions are represented by thousands of well-studied meteorites. A successful program of NEO spacecraft exploration has begun, and we are proposing Deep Interior as the next logical step. Our mission objective is to image the deep interior structure of two NEOs using radio reflection tomography (RRT), in order to explore the record of asteroid origin and impact evolution, and to test the fundamental hypothesis that these important members of the solar system are rubble piles rather than consolidated bodies. Asteroid Interiors. Our mission's RRT technique is like a CAT scan from orbit. Closely sampled radar echoes yield volumetric maps of mechanical and compositional boundaries, and measure interior material dielectric properties. Exteriors. We use color imaging to explore the surface expressions of unit boundaries, in order to relate interior radar imaging to what is observable from spacecraft imaging and from Earth. Gravity and high fidelity geodesy are used to explore how interior structure is expressed in shape, density, mass distribution and spin. Diversity. We first visit a common, primitive, S-type asteroid. We next visit an asteroid that was perhaps blasted from the surface of a differentiated asteroid. We attain an up-close and inside look at two taxonomic archetypes spanning an important range of NEO mass and spin rate. Scientific focus is achieved by keeping our payload simple: Radar. A 30-m (tip-to-tip) cross-dipole antenna system operates at 5 and 15-MHz, with electronics heritage from JPL's MARSIS contribution to Mars Express, and antenna heritage from IMAGE and LACE. The 5-MHz channel is designed to penetrate >1 km of basaltic rock, and 15-MHz penetrates a few 100 m or more. They bracket the diversity of solar system materials that we are likely to

  12. Implementing the First Cross-border Professional Development Online Course through International E-mentoring: Reflections and Perspectives

    Directory of Open Access Journals (Sweden)

    Buddhini Gayathri Jayatilleke

    2017-03-01

    Full Text Available This research paper discusses the accomplishments, issues, and challenges experienced by Open University of Sri Lanka (OUSL academics when offering the first cross-border professional development online course to train online tutors and mentors. The course was delivered exclusively online and facilitated by OUSL academics and e-mentors from the USA. The course was comprised of 30 participants: 9 from Pakistan, 10 from Mauritius and 11 from Sri Lanka. This qualitative study is based on reflections of both faculty and participants. Data were collected using reflections and informal anecdotal records of the three OUSL academics and self-reflection instruments (pre, mid and final administered to participants, and reflective journal entries made by participants. Participants’ views were triangulated with the reflections of the OUSL academics to validate the results. While there were many accomplishments in the design and delivery of the course, the findings revealed that there were many challenges in implementing the course: pedagogical, organizational and technological aspects in particular. The paper provides recommendations to address such challenges when offering cross-border online courses in the future.

  13. Josephson current and Andreev level dynamics in nanoscale superconducting weak links

    Energy Technology Data Exchange (ETDEWEB)

    Brunetti, Aldo

    2014-11-15

    In this thesis we focus on the interplay between proximity induced superconducting correlations and Coulomb interactions in a Josephson junction: i.e., in a system where two superconductors modeled as two s-wave superconductors at a phase difference φ are contacted by means of a weak link, in our case a quantum dot located in the contact. In the first part we study the Josephson current-phase relation for a multi-level quantum dot tunnel-contacted by two conventional s-waves superconductors. We determine in detail the conditions for observing a finite anomalous Josephson current, i.e. a supercurrent flowing at zero phase difference in a two-level dot with spin-orbit interactions, a weak magnetic (Zeeman) field, and in the presence of Coulomb interactions. This leads to an onset behavior I{sub a}∝sgn(B), interpreted as the sign of an incipient spontaneous breakdown of time-reversal symmetry. Moreover, we will provide conditions for realizing spatially separated - but topologically unprotected - Majorana bound states, whose signature in the system will be detectable via the current-phase relation. In the second part of the thesis, we address the Andreev bound state population dynamics in superconducting weak links (a superconducting 'atomic contact'), in which a poisoning mechanism due to the trapping of single quasiparticles can occur. Our motivation is that quantum coherent superconducting circuits are the most promising candidates for future large-scale quantum information processing devices. Moreover, quasiparticle poisoning has recently been observed in devices which contain a short superconducting weak link with few transport channels. We discuss a novel charge imbalance effect in the continuum quasiparticle population, which is due to phase fluctuations of the environment weakly coupled to the superconducting contact. This coupling enters the system as a transition rate connecting continuum quasiparticles and the Andreev bound state system. The

  14. Andreev spectroscopy of FeSe{sub x}Te{sub 1−x}

    Energy Technology Data Exchange (ETDEWEB)

    Fujioka, Naoya, E-mail: f-naoya@moegi.waseda.jp; Shirai, Yoshiki; Miyamoto, Yukihiro; Tachibana, Hironori; Matsuda, Azusa

    2015-11-15

    Highlights: • We fabricated FeSe{sub 0.2}Te{sub 0.8}/oxide/Pb and FeSe{sub 0.2}Te{sub 0.8}/Al/Al{sub 2}O{sub 3}/Pb junctions. • These junctions show anomalous conductance spectra and no Josephson current. • These spectra are explained by S/N interface model with extraordinarily gaps. • Except for anomalous gap values, the result is consistent with s+− symmetry. - Abstract: We fabricated two types of junctions on the c-axis plane of FeSe{sub 0.2}Te{sub 0.8} (Fe[Se,Te], T{sub c} ∼ 13 K) crystals. In the superconductor/oxide/superconductor heterojunctions with a Pb film as a counter electrode, we found a large conductance peak centered at 0 V, and a gap-like feature, which has a much higher energy scale than those reported as a gap energy of Fe[Se,Te]. In spite of a large energy scale, their temperature dependence approximately follows a BCS curve, indicating they come from superconductivity of Fe[Se,Te]. Since these structures can be understood as the results of Andreev bound state at the S/N boundary and the interference effect in the normal metal [1], we tried to identify the effect of a normal layer by fabricating Fe[Se,Te]/Al/Al{sub 2}O{sub 3}/Pb junction. Here, we could realize a clean controlled S/N interface and the tunnel junction to investigate electronic properties of the Al slab. We found similar conductance spectra as those junctions without Al layer, giving a support that the anomalous conductance spectra come from the effect of the S/N interface. As expected, the energy scale of the observed features was reduced when the thickness of the normal metal was increased. The absence of Josephson current and the existence of an Andreev bound state may be a signature of the sign-reversal paring in Fe[Se,Te].

  15. Reflected Light from Giant Planets in Habitable Zones: Tapping into the Power of the Cross-Correlation Function.

    Science.gov (United States)

    Martins, J H C; Santos, N C; Figueira, P; Melo, C

    2016-11-01

    The direct detection of reflected light from exoplanets is an excellent probe for the characterization of their atmospheres. The greatest challenge for this task is the low planet-to-star flux ratio, which even in the most favourable case is of the order of 10 -4 in the optical. This ratio decreases even more for planets in their host's habitable zone, typically lower than 10 -7 . To reach the signal-to-noise level required for such detections, we propose to unleash the power of the Cross Correlation Function in combination with the collecting power of next generation observing facilities. The technique we propose has already yielded positive results by detecting the reflected spectral signature of 51 Pegasi b (see Martins et al. 2015). In this work, we attempted to infer the number of hours required for the detection of several planets in their host's habitable zone using the aforementioned technique from theoretical EELT observations. Our results show that for 5 of the selected planets it should be possible to directly recover their reflected spectral signature.

  16. Surface Andreev Bound States and Odd-Frequency Pairing in Topological Superconductor Junctions

    Science.gov (United States)

    Tanaka, Yukio; Tamura, Shun

    2018-04-01

    In this review, we summarize the achievement of the physics of surface Andreev bound states (SABS) up to now. The route of this activity has started from the physics of SABS of unconventional superconductors where the pair potential has a sign change on the Fermi surface. It has been established that SABS can be regarded as a topological edge state with topological invariant defined in the bulk Hamiltonian. On the other hand, SABS accompanies odd-frequency pairing like spin-triplet s-wave or spin-singlet p-wave. In a spin-triplet superconductor junction, induced odd-frequency pairing can penetrate into a diffusive normal metal (DN) attached to the superconductor. It causes so called anomalous proximity effect where the local density of states of quasiparticle in DN has a zero energy peak. When bulk pairing symmetry is spin-triplet px-wave, the anomalous proximity effect becomes prominent and the zero bias voltage conductance is always quantized independent of the resistance in DN and interface. Finally, we show that the present anomalous proximity effect is realized in an artificial topological superconducting system, where a nanowire with spin-orbit coupling and Zeeman field is put on the conventional spin-singlet s-wave superconductor.

  17. A cross sectional study at subcentre level reflecting need for improving coverage of maternal health services

    Directory of Open Access Journals (Sweden)

    Geetu Singh

    2015-03-01

    Full Text Available Background: A Health Sub-centre is the most peripheral and first point of contact between the primary health care system and the community. It is imperative to get insight into their functioning which were established with the objectives of minimizing the hardships of the rural people. Objective: To study the coverages of maternal services at subcentres in district Jhansi. Material & Methods: A cross-sectional study was conducted with sample of 20 subcentres in the district Jhansi from June 2012 to July 2013. Various records of the Health workers were examined for maternal health services coverages and noted down on a pre-designed questionnaire. Results: Present study showed that currently married pregnant women aged 15-49 years registered for ANC were 72.1%. Women who received antenatal check-up in first trimester in subcentres were around 50%. Women who received 3 or more antenatal visits were only 29% in study. Meager 3.6% women received IFA for 100 days or more. Similarly women with full antenatal check-up were only 3%. In current study it was found that family planning coverages for female Sterilization was 60% but male Sterilization was just 0.5%. Conclusion: Higher emphasis needs to be given for better coverage of all maternal services. There should be provision for improvement of competence, confidence and motivation of health workers to ensure full range of maternal care activities specified under NRHM program.

  18. A Standardized Narrative Profile Approach to Self-Reflection and Assessment of Cross-Cultural Communication

    Directory of Open Access Journals (Sweden)

    Kyle J Wilby

    2017-03-01

    Full Text Available Objectives: 1 to explore clinical assessor’s values regarding behaviours related to cultural aspects of care, 2 to generate standardized narrative profiles regarding cultural behavioural outcomes within clinical teaching settings, and 3 to rank order standardized narrative profiles according to performance expectations. Methods: Ten interviews were completed with clinicians to determine values and performance expectations for culturally competent behaviours. Transcripts were produced and coded. Six narrative profiles were developed based on data obtained. Twenty clinicians categorized profiles according to performance expectations and rank ordered. Intraclass correlation coefficients (ICCs determined inter-rater reliability. Clinicians rated usability of profiles in clinical training settings. Results: Eighteen categories were coded with communication, awareness and ability most frequently reported with each ranging from 9.6-11.5% of the utterances. Consensus for categorization of all profiles was achieved at a level of 70% (ICC = 0.837, 95% CI 0.654-0.969. High inter-rater reliability was achieved for rank ordering (ICC = 0.815, 95% CI 0.561 to 0.984. Seventeen (85% clinicians agreed that the profiles would be usable in clinical training settings. Conclusions: Standardized narrative profiles may aid assessment and self-reflection for student performance within culturally diverse interactions. Conflict of Interest We declare no conflicts of interest or financial interests that the authors or members of their immediate families have in any product or service discussed in the manuscript, including grants (pending or received, employment, gifts, stock holdings or options, honoraria, consultancies, expert testimony, patents and royalties.   Type: Original Research

  19. A new laser reflectance system capable of measuring changing cross-sectional area of soft tissues during tensile testing.

    Science.gov (United States)

    Pokhai, Gabriel G; Oliver, Michele L; Gordon, Karen D

    2009-09-01

    Determination of the biomechanical properties of soft tissues such as tendons and ligaments is dependent on the accurate measurement of their cross-sectional area (CSA). Measurement methods, which involve contact with the specimen, are problematic because soft tissues are easily deformed. Noncontact measurement methods are preferable in this regard, but may experience difficulty in dealing with the complex cross-sectional shapes and glistening surfaces seen in soft tissues. Additionally, existing CSA measurement systems are separated from the materials testing machine, resulting in the inability to measure CSA during testing. Furthermore, CSA measurements are usually made in a different orientation, and with a different preload, prior to testing. To overcome these problems, a noncontact laser reflectance system (LRS) was developed. Designed to fit in an Instron 8872 servohydraulic test machine, the system measures CSA by orbiting a laser transducer in a circular path around a soft tissue specimen held by tissue clamps. CSA measurements can be conducted before and during tensile testing. The system was validated using machined metallic specimens of various shapes and sizes, as well as different sizes of bovine tendons. The metallic specimens could be measured to within 4% accuracy, and the tendons to within an average error of 4.3%. Statistical analyses showed no significant differences between the measurements of the LRS and those of the casting method, an established measurement technique. The LRS was successfully used to measure the changing CSA of bovine tendons during uniaxial tensile testing. The LRS developed in this work represents a simple, quick, and accurate way of reconstructing complex cross-sectional profiles and calculating cross-sectional areas. In addition, the LRS represents the first system capable of automatically measuring changing CSA of soft tissues during tensile testing, facilitating the calculation of more accurate biomechanical properties.

  20. Giant Andreev Backscattering through a Quantum Point Contact Coupled via a Disordered Two-Dimensional Electron Gas to Superconductors

    International Nuclear Information System (INIS)

    den Hartog, S.G.; van Wees, B.J.; Klapwijk, T.M.; Nazarov, Y.V.; Borghs, G.

    1997-01-01

    We have investigated the superconducting-phase-modulated reduction in the resistance of a ballistic quantum point contact (QPC) connected via a disordered two-dimensional electron gas (2DEG) to superconductors. We show that this reduction is caused by coherent Andreev backscattering of holes through the QPC, which increases monotonically by reducing the bias voltage to zero. In contrast, the magnitude of the phase-dependent resistance of the disordered 2DEG displays a nonmonotonic reentrant behavior versus bias voltage. copyright 1997 The American Physical Society

  1. Coherent diffusive transport mediated by Andreev reflections at V=Delta/e in a mesoscopic superconductor/semiconductor/superconductor junction

    DEFF Research Database (Denmark)

    Kutchinsky, Jonatan; Taboryski, Rafael Jozef; Kuhn, Oliver

    1997-01-01

    We present experiments revealing a singularity in the coherent current across a superconductor/semiconductor/superconductor (SSmS) junction at the bias voltage corresponding to the superconducting energy gap V=Delta/e. The SSmS structure consists of highly doped GaAs with superconducting electrodes...

  2. Spin polarization of a Ferromagnetic Narrow Gap p-(In,Mn)As Obtained from Andreev Reflection Spectroscopy

    International Nuclear Information System (INIS)

    Akazaki, T.; Munekata, H.; Yokoyama, T.; Tanaka, Y.; Takayanagi, H.

    2011-01-01

    Spin-polarized carrier transport across Nb/p-(In,Mn)As junctions has been studied. Suppressions of conductance in the superconductor sub-gap region and conductance peaks at the bias voltage around the edge of the sub-gap are observed. These features are well reproduced by a newly modified BTK model including both spin polarization and the inverse proximity effect. The value of spin polarization in p-(In,Mn)As extracted by the calculation is P = 0.725 at 0.5 K with Z = 0.25

  3. Coherent diffusive transport mediated by Andreev reflections at V=Δ/e in a mesoscopic superconductor/semiconductor/superconductor junction

    International Nuclear Information System (INIS)

    Kutchinsky, J.; Taboryski, R.; Kuhn, O.; So/rensen, C.B.; Lindelof, P.E.; Kristensen, A.; Hansen, J.B.; Jacobsen, C.S.; Skov, J.L.

    1997-01-01

    We present experiments revealing a singularity in the coherent current across a superconductor/semiconductor/superconductor (SSmS) junction at the bias voltage corresponding to the superconducting energy gap V=Δ/e. The SSmS structure consists of highly doped GaAs with superconducting electrodes of aluminum configured as an interferometer. The phase-coherent component of the current is probed as the amplitude of h/2e vs magnetic-field oscillations in the differential resistance of the interferometer. copyright 1997 The American Physical Society

  4. Distinction between critical current effects and intrinsic anomalies in the point-contact Andreev reflection spectra of unconventional superconductors

    Science.gov (United States)

    He, Ge; Wei, Zhong-Xu; Brisbois, Jérémy; Jia, Yan-Li; Huang, Yu-Long; Zhou, Hua-Xue; Ni, Shun-Li; Silhanek, Alejandro V.; Shan, Lei; Zhu, Bei-Yi; Yuan, Jie; Dong, Xiao-Li; Zhou, Fang; Zhao, Zhong-Xian; Jin, Kui

    2018-04-01

    Not Available Project supported by the National Key Basic Research Program of China (Grant Nos. 2015CB921000, 2016YFA0300301, and 2017YFA0302902), the National Natural Science Foundation of China (Grant Nos. 11674374 and 1474338), the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (Grant No. QYZDB-SSW-SLH008), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDB07020100 and XDB07030200), the Beijing Municipal Science and Technology Project (Grant No. Z161100002116011), the Fonds de la Recherche Scientifique–FNRS and the ARC Grant 13/18-08 for Concerted Research Actions, financed by the French Community of Belgium (Wallonia-Brussels Federation). Jérémy Brisbois acknowledges the support from F.R.S.–FNRS (Research Fellowship), The work of Alejandro V Silhanek is partially supported by PDR T.0106.16 of the F.R.S.–FNRS..

  5. Studying flow close to an interface by total internal reflection fluorescence cross-correlation spectroscopy: Quantitative data analysis

    Science.gov (United States)

    Schmitz, R.; Yordanov, S.; Butt, H. J.; Koynov, K.; Dünweg, B.

    2011-12-01

    Total internal reflection fluorescence cross-correlation spectroscopy (TIR-FCCS) has recently [S. Yordanov , Optics ExpressOPEXFF1094-408710.1364/OE.17.021149 17, 21149 (2009)] been established as an experimental method to probe hydrodynamic flows near surfaces, on length scales of tens of nanometers. Its main advantage is that fluorescence occurs only for tracer particles close to the surface, thus resulting in high sensitivity. However, the measured correlation functions provide only rather indirect information about the flow parameters of interest, such as the shear rate and the slip length. In the present paper, we show how to combine detailed and fairly realistic theoretical modeling of the phenomena by Brownian dynamics simulations with accurate measurements of the correlation functions, in order to establish a quantitative method to retrieve the flow properties from the experiments. First, Brownian dynamics is used to sample highly accurate correlation functions for a fixed set of model parameters. Second, these parameters are varied systematically by means of an importance-sampling Monte Carlo procedure in order to fit the experiments. This provides the optimum parameter values together with their statistical error bars. The approach is well suited for massively parallel computers, which allows us to do the data analysis within moderate computing times. The method is applied to flow near a hydrophilic surface, where the slip length is observed to be smaller than 10nm, and, within the limitations of the experiments and the model, indistinguishable from zero.

  6. Coherence-enhanced phase-dependent dissipation in long SNS Josephson junctions: Revealing Andreev bound state dynamics

    Science.gov (United States)

    Dassonneville, B.; Murani, A.; Ferrier, M.; Guéron, S.; Bouchiat, H.

    2018-05-01

    One of the best known causes of dissipation in ac-driven quantum systems stems from photon absorption causing transitions between levels. Dissipation can also be caused by the retarded response to the time-dependent excitation, and in general gives insight into the system's relaxation times and mechanisms. Here we address the dissipation in a mesoscopic normal wire with superconducting contacts, that sustains a dissipationless supercurrent at zero frequency and that may therefore naively be expected to remain dissipationless at a frequency lower than the superconducting gap. We probe the high-frequency linear response of such a normal metal/superconductor (NS) ring to a time-dependent flux by coupling it to a highly sensitive multimode microwave resonator. Far from being the simple, dissipationless derivative of the supercurrent-versus-phase relation, the ring's ac susceptibility also displays a dissipative component whose phase dependence is a signature of the dynamical processes occurring within the Andreev spectrum. We show how dissipation is driven by the competition between two mechanisms. The first is the relaxation of the Andreev level distribution function, while the second corresponds to microwave-induced transitions within the spectrum. Depending on the relative strength of those contributions, dissipation can be maximal at π , a phase at which the proximity-induced minigap closes, or can be maximal near π /2 , a phase at which the dc supercurrent is maximal. We also find that the dissipative response paradoxically increases at low temperature and can even exceed the normal-state conductance. The results are successfully confronted with theoretical predictions of the Kubo linear response and time-dependent Usadel equations, derived from the Bogoliubov-de Gennes Hamiltonian describing the SNS junction. These experiments thus demonstrate the power of the ac susceptibility measurement of individual hybrid mesoscopic systems in probing in a controlled way

  7. Andreev reflection through a ferromagnet-quantum dot-superconductor system with intradot Coulomb correlations

    Directory of Open Access Journals (Sweden)

    Rudziński Wojciech

    2013-01-01

    Full Text Available Spin-dependent tunneling through a quantum dot coupled to one ferromagnetic and one superconducting electrodes is studied in the Andreev reflection (AR regime. Electrical conductance is calculated within the nonequilibrium Green function technique. Effects due to a competition between the Coulomb correlations on the dot and intradot spin-flip processes are considered in the linear transport regime and for different coupling strengths between the dot and the external electrodes. It is shown that when a coherent spin rotation is present on the dot, Coulomb interactions may lead to a significant enhancement of the AR tunneling current and even to the perfect AR transmission. Origin of occurrence of a variety of the multipeak structure of the linear conductance is also discussed.

  8. Experimental investigation of supercurrent enhancement in S-N-S junctions by non-equilibrium injection into supercurrent-carrying bound Andreev states

    DEFF Research Database (Denmark)

    Kutchinsky, Jonatan; Taboryski, Rafael Jozef; Sørensen, C B

    2001-01-01

    We report measurements on three-terminal superconductor-semiconductor-superconductor injection devices demonstrating enhancement of the supercurrent by injection from a superconducting injector electrode. Two other electrodes were used to form the detector junction. Applying a small voltage...... of enhancement of the supercurrent by non-equilibrium injection into bound supercurrent-carrying Andreev states. The effect persists to temperatures where the equilibrium supercurrent has vanished. (C) 2001 Elsevier Science B.V. All rights reserved....

  9. Evidence of a visual-to-auditory cross-modal sensory gating phenomenon as reflected by the human P50 event-related brain potential modulation.

    Science.gov (United States)

    Lebib, Riadh; Papo, David; de Bode, Stella; Baudonnière, Pierre Marie

    2003-05-08

    We investigated the existence of a cross-modal sensory gating reflected by the modulation of an early electrophysiological index, the P50 component. We analyzed event-related brain potentials elicited by audiovisual speech stimuli manipulated along two dimensions: congruency and discriminability. The results showed that the P50 was attenuated when visual and auditory speech information were redundant (i.e. congruent), in comparison with this same event-related potential component elicited with discrepant audiovisual dubbing. When hard to discriminate, however, bimodal incongruent speech stimuli elicited a similar pattern of P50 attenuation. We concluded to the existence of a visual-to-auditory cross-modal sensory gating phenomenon. These results corroborate previous findings revealing a very early audiovisual interaction during speech perception. Finally, we postulated that the sensory gating system included a cross-modal dimension.

  10. 14C/C measurements support Andreev's internode method to determine lichen growth rates in Cladina stygia (Fr.) Ahti

    Energy Technology Data Exchange (ETDEWEB)

    Holt, E; Bench, G

    2007-12-05

    Growth rates and the ability to date an organism can greatly contribute to understanding its population biology and community dynamics. 1n 1954, Andreev proposed a method to date Cladina, a fruticose lichen, using total thallus length and number of internodes. No research, however, has demonstrated the reliability of this technique or compared its estimates to those derived by other means. In this study, we demonstrate the utility of {sup 14}C/C ratios to determine lichen age and growth rate in Cladina stygia (Fr.) Ahti collected from northwestern Alaska, USA. The average growth rate using {sup 14}C/C ratios was 6.5 mm {center_dot} yr{sup -1}, which was not significantly different from growth rates derived by Andreev's internode method (average = 6.2 mm {center_dot} yr{sup -1}); thus, suggesting the reliability of Andreev's simple field method for dating lichens. In addition, we found lichen growth rates appeared to differ with geographic location, yet did not seem related to ambient temperature and total precipitation.

  11. Slow neutron total cross-section, transmission and reflection calculation for poly- and mono-NaCl and PbF{sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Mansy, Muhammad S., E-mail: mmansy88@asrt.sci.eg [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt); Radioactive Waste Management Unit, Hot Labs Centre, Atomic Energy Authority, Cairo (Egypt); Adib, M.; Habib, N. [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt); Bashter, I.I. [Physics Department, Faculty of Science, Zagazig University (Egypt); Morcos, H.N.; El-Mesiry, M.S. [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt)

    2016-10-01

    Highlights: • Slow neutron cross-section calculation for poly- and mono-crystalline materials. • Monochromatic features of PbF{sub 2} and NaCl mono-crystals. • Characterization of poly- and mono-crystal filters used in neutron diffraction. • Computer code developed calculates neutron cross-section, transmission & reflection. - Abstract: A detailed study about the calculation of total neutron cross-section, transmission and reflection from crystalline materials was performed. The developed computer code is approved to be sufficient for the required calculations, also an excellent agreement has been shown when comparing the code results with the other calculated and measured values. The optimal monochromator and filter parameters were discussed in terms of crystal orientation, mosaic spread, and thickness. Calculations show that 30 cm thick of PbF{sub 2} poly-crystal is an excellent cold neutron filter producing neutron wavelengths longer than 0.66 nm needed for the investigation of magnetic structure experiments. While mono-crystal filter PbF{sub 2} cut along its (1 1 1), having mosaic spread (η = 0.5°) and thickness 10 cm can only transmit thermal neutrons of the desired wavelengths and suppress epithermal and γ-rays forming unwanted background, when it is cooled to liquid nitrogen temperature. NaCl (2 0 0) and PbF{sub 2} (1 1 1) monochromator crystals having mosaic spread (η = 0.5°) and thickness 10 mm shows high neutron reflectivity for neutron wavelengths (λ = 0.114 nm and λ = 0.43 nm) when they used as a thermal and cold neutron monochromators respectively with very low contamination from higher order reflections.

  12. Fault-related-folding structures and reflection seismic sections. Study by seismic modeling and balanced cross section; Danso ga kaizaisuru shukyoku kozo no keitai to jishin tansa danmen. 2. Seismic modeling oyobi balanced cross section ni yoru study

    Energy Technology Data Exchange (ETDEWEB)

    Tamagawa, T; Matsuoka, T [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsukui, R [Japan National Oil Corp., Tokyo (Japan). Technology Research Center

    1997-05-27

    It occasionally happens that there exists a part where reflection near the thrust is not clearly observed in a thrust zone seismic survey cross section. For the effective interpretation of such an occurrence, the use of geological structures as well as the reflected pattern is effective. When the velocity structures for a fold structure having a listric fault caused anticline (unidirectionally inclined with a backlimb, without a forelimb) and for a fault propagation fold are involved, a wrong interpretation may be made since they look alike in reflection wave pattern despite their difference in geological structure. In the concept of balanced cross section, a check is performed, when the stratum after deformation is recovered to the time of deposition, as to whether the geologic stratum area is conserved without excess or shortage. An excess or shortage occurs if there is an error in the model, and this shows that the fault surface or fold structure is not correctly reflected. Positive application of geological knowledge is required in the processing and interpreting of data from a seismic survey. 6 refs., 6 figs.

  13. A Feminist Reflection on Ethnographic Research in China: Gender, Sex, and Power in Cross-Cultural Context

    Directory of Open Access Journals (Sweden)

    Arianne M. Gaetano

    2016-03-01

    Full Text Available As a feminist cultural anthropologist specializing in social transformations in contemporary China, my research and teaching necessarily involves exploring the construction of difference, the intersectionality of gender with other social positions, and how difference upholds or challenges power. In this essay, I employ biographical reflection to illustrate how my everyday experiences as a student, foreign English teacher, and scholarly researcher in China have refined my awareness of these important insights of feminist theory. As my attention to these processes increased, I became more mindful of the myriad ways women negotiate cultural configurations of gender and power in their everyday lives. Personal experiences also prompted me to reflect on how my identity and positionality impact the research process and outcomes. Thus experiential knowledge greatly enriched my study and understanding of the changing lives of women in China. I suggest how educators can impart these valuable lessons to students through experiential learning.

  14. Cross-calibration of S-NPP VIIRS moderate-resolution reflective solar bands against MODIS Aqua over dark water scenes

    Science.gov (United States)

    Sayer, Andrew M.; Hsu, N. Christina; Bettenhausen, Corey; Holz, Robert E.; Lee, Jaehwa; Quinn, Greg; Veglio, Paolo

    2017-04-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) is being used to continue the record of Earth Science observations and data products produced routinely from National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS) measurements. However, the absolute calibration of VIIRS's reflected solar bands is thought to be biased, leading to offsets in derived data products such as aerosol optical depth (AOD) as compared to when similar algorithms are applied to different sensors. This study presents a cross-calibration of these VIIRS bands against MODIS Aqua over dark water scenes, finding corrections to the NASA VIIRS Level 1 (version 2) reflectances between approximately +1 and -7 % (dependent on band) are needed to bring the two into alignment (after accounting for expected differences resulting from different band spectral response functions), and indications of relative trending of up to ˜ 0.35 % per year in some bands. The derived calibration gain corrections are also applied to the VIIRS reflectance and then used in an AOD retrieval, and they are shown to decrease the bias and total error in AOD across the mid-visible spectral region compared to the standard VIIRS NASA reflectance calibration. The resulting AOD bias characteristics are similar to those of NASA MODIS AOD data products, which is encouraging in terms of multi-sensor data continuity.

  15. Detection and control of broken symmetries with Andreev bound state tunneling spectroscopy: effects of atomic-scale disorder

    International Nuclear Information System (INIS)

    Greene, L.H.; Hentges, P.J.; Aubin, H.; Aprili, M.; Badica, E.; Covington, M.; Pafford, M.M.; Westwood, G.; Klemperer, W.G.; Jian, Sha; Hinks, D.G.

    2004-01-01

    Quasiparticle planar tunneling spectroscopy is used to study unconventional superconductivity in YBa 2 Cu 3 O 7 (YBCO) thin films and Bi 2 Sr 2 CaCu 2 O 8 (BSCCO) single crystals. Tunneling conductances are obtained as a function of crystallographic orientation, applied magnetic field (magnitude and orientation), atomic substitution and surface damage. Our systematic studies confirm that the observed zero-bias conductance peak (ZBCP), a measure of the near-surface quasiparticle (QP) density of states (DoS), is comprised of Andreev bound states (ABS) resulting directly from the sign change of the d-wave order parameter (OP) at the Fermi surface. Our data, plus a literature search, reveals a consistency in the observation of the splitting of the ZBCP in optimally-doped materials. We note that the splitting of the ZBCP observed in applied field, and the spontaneous splitting observed at lower temperatures in zero field, occur concomitantly in a given junction, and that observation of this splitting is dependent upon two parameters: (1) the magnitude of the tunneling cone and (2) the degree of atomic-scale disorder at the interface

  16. Reflections on “Crossing Borders in Birthing Practices”: Hmong in Northern Thailand and Saint Paul, Minnesota

    Directory of Open Access Journals (Sweden)

    Kathleen A. Culhane-Pera

    2014-12-01

    Full Text Available As a family physician and medical anthropologist, I have interacted with pregnant women and their families in Minnesota since 1983 and in one Hmong village in Northern Thailand since 1988. In the previous article I describe our recent research about Hmong families’ pregnancy and birth practices in Thailand. In this article, I reflect upon the differences in Minnesota and Thailand, consider what socio-cultural factors may be influencing people’s experiences, and speculate that Minnesota Hmong experiences could be helpful to Thai Hmong.

  17. Slow neutron total cross-section, transmission and reflection calculation for poly- and mono-NaCl and PbF2 crystals

    Science.gov (United States)

    Mansy, Muhammad S.; Adib, M.; Habib, N.; Bashter, I. I.; Morcos, H. N.; El-Mesiry, M. S.

    2016-10-01

    A detailed study about the calculation of total neutron cross-section, transmission and reflection from crystalline materials was performed. The developed computer code is approved to be sufficient for the required calculations, also an excellent agreement has been shown when comparing the code results with the other calculated and measured values. The optimal monochromator and filter parameters were discussed in terms of crystal orientation, mosaic spread, and thickness. Calculations show that 30 cm thick of PbF2 poly-crystal is an excellent cold neutron filter producing neutron wavelengths longer than 0.66 nm needed for the investigation of magnetic structure experiments. While mono-crystal filter PbF2 cut along its (1 1 1), having mosaic spread (η = 0.5°) and thickness 10 cm can only transmit thermal neutrons of the desired wavelengths and suppress epithermal and γ-rays forming unwanted background, when it is cooled to liquid nitrogen temperature. NaCl (2 0 0) and PbF2 (1 1 1) monochromator crystals having mosaic spread (η = 0.5°) and thickness 10 mm shows high neutron reflectivity for neutron wavelengths (λ = 0.114 nm and λ = 0.43 nm) when they used as a thermal and cold neutron monochromators respectively with very low contamination from higher order reflections.

  18. Analysis of perceived risk among construction workers: a cross-cultural study and reflection on the Hofstede model.

    Science.gov (United States)

    Martinez-Fiestas, Myriam; Rodríguez-Garzón, Ignacio; Delgado-Padial, Antonio; Lucas-Ruiz, Valeriano

    2017-09-01

    This article presents a cross-cultural study on perceived risk in the construction industry. Worker samples from three different countries were studied: Spain, Peru and Nicaragua. The main goal was to explain how construction workers perceive their occupational hazard and to analyze how this is related to their national culture. The model used to measure perceived risk was the psychometric paradigm. The results show three very similar profiles, indicating that risk perception is independent of nationality. A cultural analysis was conducted using the Hofstede model. The results of this analysis and the relation to perceived risk showed that risk perception in construction is independent of national culture. Finally, a multiple lineal regression analysis was conducted to determine what qualitative attributes could predict the global quantitative size of risk perception. All of the findings have important implications regarding the management of safety in the workplace.

  19. Reflections on the Abolition of Exequatur in the Cross-border Cases Regarding the Return of the Child

    Directory of Open Access Journals (Sweden)

    Gabriela LUPŞAN

    2015-08-01

    Full Text Available Free circulation of judgments within the EU of the authentic instruments and agreements in matrimonial matters and in matters of parental responsibility is provided for in Regulation (EC no. 2201/2003 of the Council of 27 November 2003 concerning jurisdiction, recognition and enforcement of judgments in matrimonial matters and in matters of parental responsibility, repealing Regulation (EC no. 1347/2000. For two categories of judgments, this Regulation provides for the suppression of exequatur. In this article we intend to continue analyzing the suppression of the exequatur under the situation of judgments in family law matters, relating to the return of the child in the cross-border cases, on judgments passed in another Member State.

  20. Western lowland gorilla diet and resource availability: new evidence, cross-site comparisons, and reflections on indirect sampling methods.

    Science.gov (United States)

    Doran, Diane M; McNeilage, Alastair; Greer, David; Bocian, Carolyn; Mehlman, Patrick; Shah, Natasha

    2002-11-01

    We describe the resource availability and diet of western lowland gorillas (Gorilla gorilla gorilla) from a new study site in the Central African Republic and Republic of Congo based on 3 years of study. The results, based on 715 fecal samples and 617 days of feeding trails, were similar to those reported from three other sites, in spite of differences in herb and fruit availability. Staple foods (consumed year-round) included high-quality herbs (Haumania), swamp herbs (when present), and a minimal diversity of fruit. A variety of fruits (average of 3.5 species per day and 10 per month) were selectively consumed; gorillas ignored some common fruits and incorporated rare fruits to a degree higher than predicted based on availability. During periods of fruit abundance, fruit constituted most of the diet. When succulent fruits were unavailable, gorillas used low-quality herbs (i.e., low-protein), bark, and more fibrous fruits as fallback foods. Fibrous fruit species, such as Duboscia macrocarpa and Klainedoxa gabonensis, were particularly important to gorillas at Mondika and other sites as fallbacks. The densities of these two species are similar across sites for which data are available, in spite of major differences in forest structure, suggesting they may be key species in determining gorilla density. No sex difference in diet was detected. Such little variation in western lowland gorilla diet across sites and between sexes was unexpected and may partly reflect limitations of indirect sampling. Copyright 2002 Wiley-Liss, Inc.

  1. Health-Seeking Influence Reflected by Online Health-Related Messages Received on Social Media: Cross-Sectional Survey.

    Science.gov (United States)

    Iftikhar, Rahila; Abaalkhail, Bahaa

    2017-11-16

    Major social networking platforms, such as Facebook, WhatsApp, and Twitter, have become popular means through which people share health-related information, irrespective of whether messages disseminated through these channels are authentic. This study aims to describe the demographic characteristics of patients that may demonstrate their attitudes toward medical information shared on social media networks. Second, we address how information found through social media affects the way people deal with their health. Third, we examine whether patients initiate or alter/discontinue their medications based on information derived from social media. We conducted a cross-sectional survey between April and June 2015 on patients attending outpatient clinics at King Abdulaziz University, Jeddah, Saudi Arabia. Patients who used social media (Facebook, WhatsApp, and Twitter) were included. We designed a questionnaire with closed-ended and multiple-choice questions to assess the type of social media platforms patients used and whether information received on these platforms influenced their health care decisions. We used chi-square test to establish the relationship between categorical variables. Of the 442 patients who filled in the questionnaires, 401 used Facebook, WhatsApp, or Twitter. The majority of respondents (89.8%, 397/442) used WhatsApp, followed by Facebook (58.6%, 259/442) and Twitter (42.3%, 187/442). In most cases, respondents received health-related messages from WhatsApp and approximately 42.6% (171/401) reported ever stopping treatment as advised on a social media platform. A significantly higher proportion of patients without heart disease (P=.001) and obese persons (P=.01) checked the authenticity of information received on social media. Social media messages influenced decision making among patients without heart disease (P=.04). Respondents without heart disease (P=.001) and obese persons (P=.01) were more likely to discuss health-related information

  2. Health-Seeking Influence Reflected by Online Health-Related Messages Received on Social Media: Cross-Sectional Survey

    Science.gov (United States)

    2017-01-01

    Background Major social networking platforms, such as Facebook, WhatsApp, and Twitter, have become popular means through which people share health-related information, irrespective of whether messages disseminated through these channels are authentic. Objective This study aims to describe the demographic characteristics of patients that may demonstrate their attitudes toward medical information shared on social media networks. Second, we address how information found through social media affects the way people deal with their health. Third, we examine whether patients initiate or alter/discontinue their medications based on information derived from social media. Methods We conducted a cross-sectional survey between April and June 2015 on patients attending outpatient clinics at King Abdulaziz University, Jeddah, Saudi Arabia. Patients who used social media (Facebook, WhatsApp, and Twitter) were included. We designed a questionnaire with closed-ended and multiple-choice questions to assess the type of social media platforms patients used and whether information received on these platforms influenced their health care decisions. We used chi-square test to establish the relationship between categorical variables. Results Of the 442 patients who filled in the questionnaires, 401 used Facebook, WhatsApp, or Twitter. The majority of respondents (89.8%, 397/442) used WhatsApp, followed by Facebook (58.6%, 259/442) and Twitter (42.3%, 187/442). In most cases, respondents received health-related messages from WhatsApp and approximately 42.6% (171/401) reported ever stopping treatment as advised on a social media platform. A significantly higher proportion of patients without heart disease (P=.001) and obese persons (P=.01) checked the authenticity of information received on social media. Social media messages influenced decision making among patients without heart disease (P=.04). Respondents without heart disease (P=.001) and obese persons (P=.01) were more likely to

  3. Reflecting reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    associated with reflection and an exploration of alternative conceptions that view reflection within the context of settings which have a more group- and team-based orientation. Drawing on an action research project on health care supervision, the paper questions whether we should reject earlier views...... of reflection, rehabilitate them in order to capture broader connotations or move to new ways of regarding reflection that are more in keeping with not only reflective but also emotive, normative and formative views on supervision. The paper presents a critical perspective on supervision that challenge...... the current reflective paradigm I supervision and relate this to emotive, normative and formative views supervision. The paper is relevant for Nordic educational research into the supervision and guidance...

  4. Concrete reflected cylinders of highly enriched solutions of uranyl nitrate ICSBEP Benchmark: A re-evaluation by means of MCNPX using ENDF/B-VI cross section library

    International Nuclear Information System (INIS)

    Cruzate, J.A.; Carelli, J.L.

    2011-01-01

    This work presents a theoretical re-evaluation of a set of original experiments included in the 2009 issue of the International Handbook of Evaluated Criticality Safety Benchmark Experiments, as “Concrete Reflected Cylinders of Highly Enriched Solutions of Uranyl Nitrate” (identification number: HEU-SOL-THERM- 002) [4]. The present evaluation has been made according to benchmark specifications [4], and added data taken out of the original published report [3], but applying a different approach, resulting in a more realistic calculation model. In addition, calculations have been made using the latest version of MCNPX Monte Carlo code, combined with an updated set of cross section data, the continuous-energy ENDF/B-VI library. This has resulted in a comprehensive model for the given experimental situation. Uncertainties analysis has been made based on the evaluation of experimental data presented in the HEU-SOLTHERM-002 report. Resulting calculations with the present improved physical model have been able to reproduce the criticality of configurations within 0.5%, in good agreement with experimental data. Results obtained in the analysis of uncertainties are in general agreement with those at HEU-SOL-THERM-002 benchmark document. Qualitative results from analyses made in the present work can be extended to similar fissile systems: well moderated units of 235 U solutions, reflected with concrete from all directions. Results have confirmed that neutron absorbers, even as impurities, must be taken into account in calculations if at least approximate proportions were known. (authors)

  5. Two-terminal charge tunneling: Disentangling Majorana zero modes from partially separated Andreev bound states in semiconductor-superconductor heterostructures

    Science.gov (United States)

    Moore, Christopher; Stanescu, Tudor D.; Tewari, Sumanta

    2018-04-01

    We show that a pair of overlapping Majorana bound states (MBSs) forming a partially separated Andreev bound state (ps-ABS) represents a generic low-energy feature in spin-orbit-coupled semiconductor-superconductor (SM-SC) hybrid nanowire in the presence of a Zeeman field. The ps-ABS interpolates continuously between the "garden variety" ABS, which consists of two MBSs sitting on top of each other, and the topologically protected Majorana zero modes (MZMs), which are separated by a distance given by the length of the wire. The really problematic ps-ABSs consist of component MBSs separated by a distance of the order of the characteristic Majorana decay length ξ , and have nearly zero energy in a significant range of control parameters, such as the Zeeman field and chemical potential, within the topologically trivial phase. Despite being topologically trivial, such ps-ABSs can generate signatures identical to MZMs in local charge tunneling experiments. In particular, the height of the zero-bias conductance peak (ZBCP) generated by ps-ABSs has the quantized value 2 e2/h , and it can remain unchanged in an extended range of experimental parameters, such as Zeeman field and the tunnel barrier height. We illustrate the formation of such low-energy robust ps-ABSs in two experimentally relevant situations: a hybrid SM-SC system consisting of a proximitized nanowire coupled to a quantum dot and the SM-SC system in the presence of a spatially varying inhomogeneous potential. We then show that, unlike local measurements, a two-terminal experiment involving charge tunneling at both ends of the wire is capable of distinguishing between the generic ps-ABSs and the non-Abelian MZMs. While the MZMs localized at the opposite ends of the wire generate correlated differential conduction spectra, including correlations in energy splittings and critical Zeeman fields associated with the emergence of the ZBCPs, such correlations are absent if the ZBCPs are due to ps-ABSs emerging in the

  6. Functional visual fields: a cross-sectional UK study to determine which visual field paradigms best reflect difficulty with mobility function.

    Science.gov (United States)

    Subhi, Hikmat; Latham, Keziah; Myint, Joy; Crossland, Michael

    2017-11-20

    To develop an appropriate method of assessing visual field (VF) loss which reflects its functional consequences, this study aims to determine which method(s) of assessing VF best reflect mobility difficulty. This cross-sectional observational study took place within a single primary care setting. Participants attended a single session at a University Eye Clinic, Cambridge, UK, with data collected by a single researcher (HS), a qualified optometrist. 50 adult participants with peripheral field impairment were recruited for this study. Individuals with conditions not primarily affecting peripheral visual function, such as macular degeneration, were excluded from the study. Participants undertook three custom and one standard binocular VF tests assessing VF to 60°, and also integrated monocular threshold 24-2 visual fields (IVF). Primary VF outcomes were average mean threshold, percentage of stimuli seen and VF area. VF outcomes were compared with self-reported mobility function assessed with the Independent Mobility Questionnaire, and time taken and patient acceptability were also considered. Receiver operating characteristic (ROC) curves determined which tests best predicted difficulty with mobility tasks. Greater VF loss was associated with greater self-reported mobility difficulty with all field paradigms (R 2 0.38-0.48, all Pmobility tasks in ROC analysis. Mean duration of the tests ranged from 1 min 26 s (±9 s) for kinetic assessment to 9 min 23 s (±24 s) for IVF. The binocular VF tests extending to 60° eccentricity all relate similarly to self-reported mobility function, and slightly better than integrated monocular VFs. A kinetic assessment of VF area is quicker than and as effective at predicting mobility function as static threshold assessment. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. Cross-calibration of Medium Resolution Earth Observing Satellites by Using EO-1 Hyperion-derived Spectral Surface Reflectance from "Lunar Cal Sites"

    Science.gov (United States)

    Ungar, S.

    2017-12-01

    Over the past 3 years, the Earth Observing-one (EO-1) Hyperion imaging spectrometer was used to slowly scan the lunar surface at a rate which results in up to 32X oversampling to effectively increase the SNR. Several strategies, including comparison against the USGS RObotic Lunar Observatory (ROLO) mode,l are being employed to estimate the absolute and relative accuracy of the measurement set. There is an existing need to resolve discrepancies as high as 10% between ROLO and solar based calibration of current NASA EOS assets. Although the EO-1 mission was decommissioned at the end of March 2017, the development of a well-characterized exoatmospheric spectral radiometric database, for a range of lunar phase angles surrounding the fully illuminated moon, continues. Initial studies include a comprehensive analysis of the existing 17-year collection of more than 200 monthly lunar acquisitions. Specific lunar surface areas, such as a lunar mare, are being characterized as potential "lunar calibration sites" in terms of their radiometric stability in the presence of lunar nutation and libration. Site specific Hyperion-derived lunar spectral reflectance are being compared against spectrographic measurements made during the Apollo program. Techniques developed through this activity can be employed by future high-quality orbiting imaging spectrometers (such as HyspIRI and EnMap) to further refine calibration accuracies. These techniques will enable the consistent cross calibration of existing and future earth observing systems (spectral and multi-spectral) including those that do not have lunar viewing capability. When direct lunar viewing is not an option for an earth observing asset, orbiting imaging spectrometers can serve as transfer radiometers relating that asset's sensor response to lunar values through near contemporaneous observations of well characterized stable CEOS test sites. Analysis of this dataset will lead to the development of strategies to ensure more

  8. Majorana fermion modulated nonequilibrium transport through double quantum dots

    International Nuclear Information System (INIS)

    Deng, Ming-Xun; Wang, Rui-Qiang; Ai, Bao-Quan; Yang, Mou; Hu, Liang-Bin; Zhong, Qing-Hu; Wang, Guang-Hui

    2014-01-01

    Nonequilibrium electronic transports through a double-QD-Majorana coupling system are studied with a purpose to extract the information to identify Majorana bound states (MBSs). It is found that MBSs can help form various transport processes, including the nonlocal crossed Andreev reflection, local resonant Andreev reflection, and cotunneling, depending on the relative position of two dot levels. These processes enrich the signature of average currents and noise correlations to probe the nature of MBSs. We further demonstrate the switching between the current peaks of crossed Andreev reflection and cotunneling, which is closely related to the nonlocal nature of Majorana fermions. We also propose effective physical pictures to understand these Majorana-assisted transports. - Highlights: • Majorana fermions are characterized in the signature of currents and noises. • Three types of tunneling mechanisms are realized separately. • The switching of crossed Andreev reflection and cotunneling is realized. • Concrete physical pictures are proposed to understand Majorana-assisted transports

  9. Majorana fermion modulated nonequilibrium transport through double quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Ming-Xun [Laboratory of Quantum Engineering and Quantum Materials, ICMP and SPTE, South China Normal University, Guangzhou 510006 (China); Wang, Rui-Qiang, E-mail: rqwanggz@163.com [Laboratory of Quantum Engineering and Quantum Materials, ICMP and SPTE, South China Normal University, Guangzhou 510006 (China); Ai, Bao-Quan; Yang, Mou; Hu, Liang-Bin; Zhong, Qing-Hu [Laboratory of Quantum Engineering and Quantum Materials, ICMP and SPTE, South China Normal University, Guangzhou 510006 (China); Wang, Guang-Hui [Laboratory of Nanophotonic Functional Materials and Devices, South China Normal University, Guangzhou 510006 (China)

    2014-06-13

    Nonequilibrium electronic transports through a double-QD-Majorana coupling system are studied with a purpose to extract the information to identify Majorana bound states (MBSs). It is found that MBSs can help form various transport processes, including the nonlocal crossed Andreev reflection, local resonant Andreev reflection, and cotunneling, depending on the relative position of two dot levels. These processes enrich the signature of average currents and noise correlations to probe the nature of MBSs. We further demonstrate the switching between the current peaks of crossed Andreev reflection and cotunneling, which is closely related to the nonlocal nature of Majorana fermions. We also propose effective physical pictures to understand these Majorana-assisted transports. - Highlights: • Majorana fermions are characterized in the signature of currents and noises. • Three types of tunneling mechanisms are realized separately. • The switching of crossed Andreev reflection and cotunneling is realized. • Concrete physical pictures are proposed to understand Majorana-assisted transports.

  10. Inter-band and intra-band reflections in graphene–insulator–superconductor junctions with zigzag or armchair edge

    Energy Technology Data Exchange (ETDEWEB)

    Duque, M.F., E-mail: mfduqued@unal.edu.co; Gomez P, S., E-mail: sgomezp@unal.edu.co; Herrera, W.J., E-mail: jherreraw@unal.edu.co

    2014-12-15

    We analyze electron–electron and Andreev reflections (AR) for a graphene–insulator–superconductor junction for zigzag and armchair edges, where the insulator is modeled as a potential barrier characterized by a strength. We calculate the reflection probabilities and differential conductance using the Bogoliubov–de Gennes–Dirac (BdGD) equations. For low doping values and zigzag edge the reflection coefficients have the same behavior that in a graphene–superconductor junction. However for high doping values the reflection probabilities have a periodicity of πwith the strength barrier values. For high doping values and armchair edge the electron–electron reflections associated to K′ valley increase and AR associated to K valley decrease. We compare our results with the differential conductance obtained by the Green formalism. We show that the effect of barrier strength for high doping resembles the behavior when a hopping between graphene and superconductor interfaces is considered.

  11. The Reflective Learning Continuum: Reflecting on Reflection

    Science.gov (United States)

    Peltier, James W.; Hay, Amanda; Drago, William

    2005-01-01

    The importance of reflection to marketing educators is increasingly recognized. However, there is a lack of empirical research that considers reflection within the context of both the marketing and general business education literature. This article describes the use of an instrument that can be used to measure four identified levels of a…

  12. Wave reflections from breakwaters

    OpenAIRE

    Dickson, William S.

    1994-01-01

    A new method is presented for estimating the reflection of a random, multi-directional sea from a coastal structure. The technique is applicable to an array of wave gauges of arbitrary geometry deployed seaward of the reflector. An expansion for small oblique wave incidence angles is used to derive an approximate relationship between measured array cross-spectra and a small number of parameters that describe the incident wave properties and the reflectivity of the structure. Model tests with ...

  13. Reflective photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Lentine, Anthony L.; Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat; Goeke, Ronald S.

    2018-03-06

    A photovoltaic module includes colorized reflective photovoltaic cells that act as pixels. The colorized reflective photovoltaic cells are arranged so that reflections from the photovoltaic cells or pixels visually combine into an image on the photovoltaic module. The colorized photovoltaic cell or pixel is composed of a set of 100 to 256 base color sub-pixel reflective segments or sub-pixels. The color of each pixel is determined by the combination of base color sub-pixels forming the pixel. As a result, each pixel can have a wide variety of colors using a set of base colors, which are created, from sub-pixel reflective segments having standard film thicknesses.

  14. Weaving Action Learning into the Fabric of Manufacturing: The Impact of Humble Inquiry and Structured Reflection in a Cross-Cultural Context

    Science.gov (United States)

    Luckman, Elizabeth A.

    2017-01-01

    This account of practice examines the implementation of and reactions to action learning through the Lean methodology in a unique, cross-cultural context. I review my time spent as a Lean coach; engaging with, training, and using action learning with employees in a garment manufacturing facility located in Bali, Indonesia. This research addresses…

  15. Characterisation of carbonate rocks from near-surface cross-hole and reflection GPR investigations - A case study from southeast Zealand, Denmark

    DEFF Research Database (Denmark)

    Nielsen, Lars; Looms, Majken Caroline; Hansen, Thomas Mejer

    successful in generating well-defined statistical parameters for the GPR velocity field of the subsurface than the typical strategy in which the total rock section covered by the cross-hole data is regarded as the same type of medium. Modelling strategies in which porosity data from the boreholes...

  16. Three Advantages of Cross-National Comparative Ethnography--Methodological Reflections from a Study of Migrants and Minority Ethnic Youth in English and Spanish Schools

    Science.gov (United States)

    Jørgensen, Clara Rübner

    2015-01-01

    This paper discusses the strengths of using ethnographic research methods in cross-national comparative research. It focuses particularly on the potential of applying such methods to the study of migrants and minority ethnic youth in education, where large-scale quantitative studies or single-sited ethnographies are currently dominant. By linking…

  17. Advertising execution styles as a reflection of culture : Cross-cultural analysis of messaging app advertising preferences in South Korea and China

    OpenAIRE

    Kivinen, Sofia

    2014-01-01

    Increased globalization and the thought of converging values has lead marketing practitioners and academics to consider more standardized approaches to marketing and advertising strategies. Even though cultures seem to evolve closer to each other, cultural diversity still exists. Advertising reflects and influences our cultural values and therefore it cannot be ignored when building effective advertising. Results show that culture impacts execution more than creative strategy (Wei & Jiang...

  18. Wave Reflection Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Larsen, Brian Juul

    The investigation concerns the design of a new internal breakwater in the main port of Ibiza. The objective of the model tests was in the first hand to optimize the cross section to make the wave reflection low enough to ensure that unacceptable wave agitation will not occur in the port. Secondly...

  19. Personal Reflections

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Personal Reflections. Articles in Resonance – Journal of Science Education. Volume 6 Issue 3 March 2001 pp 90-93 Personal Reflections. Why did I opt for Career in Science? Jayant V Narlikar · More Details Fulltext PDF. Volume 9 Issue 8 August 2004 pp 89-89 ...

  20. Reflection groups

    International Nuclear Information System (INIS)

    Eggermont, G.

    2006-01-01

    In 2005, PISA organised proactive meetings of reflection groups on involvement in decision making, expert culture and ethical aspects of radiation protection.All reflection group meetings address particular targeted audiences while the output publication in book form is put forward

  1. Reflection ciphers

    DEFF Research Database (Denmark)

    Boura, Christina; Canteaut, Anne; Knudsen, Lars Ramkilde

    2017-01-01

    study the necessary properties for this coupling permutation. Special care has to be taken of some related-key distinguishers since, in the context of reflection ciphers, they may provide attacks in the single-key setting.We then derive some criteria for constructing secure reflection ciphers...

  2. Quantifying Reflection

    DEFF Research Database (Denmark)

    Alcock, Gordon Lindsay

    2013-01-01

    ´ These are all based on Blooms taxonomy and levels of competence and form a major part of individual student and group learning portfolios. Key Words :Project-Based learning, Reflective Portfolios, Self assessment, Defining learning gains, Developing learning strategies , Reflections on and for learning....... It contrasts the students’ self-assessment in a range of ‘product’ skills such as Revit, Structural Design, Mathematics of construction, Technical Installations; as well as ‘process’ competencies such as ‘Working in a team’, Sharing knowledge, Maintaining a portfolio and Reflecting ON learning and FOR learning......This paper documents 1st semester student reflections on “learning to learn” in a team-based PBL environment with quantitative and qualitative student reflective feedback on the learning gains of 60 Architectural Technology and Construction Management students at VIA University College, Denmark...

  3. The Low-Back Outcome Scale and the Oswestry disability index: are they reflective of patient satisfaction after discectomy? A cross sectional study.

    Science.gov (United States)

    Azimi, Parisa; Benzel, Edward C

    2017-12-01

    The Low-Back Outcome Scale (LBOS) of Greenough and Fraser and the Oswestry disability index (ODI) were compared to the patient satisfaction index (PSI) in lumbar disc herniation (LDH) surgery. A total of 134 patients who underwent discectomy were followed through assessment of pre- and post-surgical satisfaction by the PSI, the LBOS, and the ODI. The LBOS were rated as satisfied if the outcomes were excellent or good and as dissatisfied if fair and poor. Considering the ODI, clinically satisfied was defined as a 13-point improvement from the baseline ODI scores. Phi (Φ) correlation analysis was used to study the correlation among the PSI, the LBOS and the ODI scores as proxy for patients' satisfaction. Mean age of patients was 48.9 years. Significant improvement from the pre- to post-operative ODI scores was observed. Post-surgical satisfaction based on the PSI, the ODI, and the LBOS were 70.9%, 76.8%, and 81.3%, respectively. Regarding patient satisfaction, there were weak associations between LBOS vs. PSI and ODI vs. PSI (Φ=-0.054, P=0.533) and (Φ=-0.129, P=0.136), respectively. Our study showed that the ODI and the LBOS were not reflective of patients' satisfaction after discectomy.

  4. Cross-Cultural Filmmaking as a Process of Self-Reflection: Filming Native Americans within Central European Space’s Prevailing Imagery of the “Noble Savage”

    Directory of Open Access Journals (Sweden)

    Šavelková Lívia

    2016-06-01

    Full Text Available In Said´s notion of “Orientalism” as a set of discursive practices through which the West structured the imagined East, the Czech Republic (or former Czechoslovakia in particular, and so called Eastern Europe in general, has been viewed by “the West” as a space inhabited by “exotic other”. The former socialist countries (and the so called post-socialist countries have been constructing their own “Orients” and “exotic others” as well including Noble Savage stereotype of Native Americans. This paper focuses on a visual (representation of a meeting between people who might have mutually constructed each other as the “exotic other”. Based on filming of a visit of a Native American sport team competing in the Czech Republic, the paper would like to discuss who are the “exotic ones” and for whom and the methodological issues related to the creation of the cross-cultural ethnographic films.

  5. Fault-related-folding structure and reflection seismic sections. Construction of earth model using balanced cross section; Danso ga kaizaisuru shukyoku kozo no keitai to jishin tansa danmen. 1. Balanced cross section wo mochiita chika model no kochiku

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, T; Tamagawa, T [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsukui, R [Japan National Oil Corp., Tokyo (Japan). Technology Research Center

    1997-05-27

    Pre-stacking depth migration treatment is studied for the estimation of the fold configuration from seismic survey cross sections. The estimation of a velocity structure is necessary for the execution of such treatment, and the utilization of structural-geological knowledge is required for its interpretation. The concept of balanced cross section in relation to the fault-bend fold constructs a stratum structure model under conditions that the deformation during fold and fault formation is a planar strain, that there is no change in volume due to deformation, and that a fold is a parallel fold. In addition to the above geometric and kinetic approach, there is another fold formation process simulation model using a Newtonian fluid for study from the viewpoint of dynamics. This simulation stands on the presumption that the boundary contains a ramp that had been in presence before fold formation and that an incompressible viscous matter is mounted on the top surface. The viscous matter flows and deforms for the formation of an anticline on the ramp. Such enables the reproduction of a fault-bend fold formation process, and helpful discussion may be furthered on the dynamic aspect of this simulation. 5 refs., 4 figs.

  6. A cross-sectional study: serum CCL3/MIP-1α levels may reflect lumbar intervertebral disk degeneration in Han Chinese people

    Directory of Open Access Journals (Sweden)

    Zhang YL

    2018-03-01

    Full Text Available Yi-Li Zhang,1,2,* Bei Li,1,2,* Zeng-Huan Zhou1 1School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, People’s Republic of China; 2School of Health Services Management, Southern Medical University, Guangzhou, Guangdong Province, People’s Republic of China *These authors contributed equally to this work Background: The macrophage inflammatory protein-1α (MIP-1α, also named chemokine cytokine ligand 3 (CCL3, has been detected in nucleus pulposus and increased following cytokine stimulation. Objective: The current study was performed to explore the relationship between serum CCL3/MIP-1α levels with lumbar intervertebral disk degeneration (IDD. Patients and methods: A total of 132 disk degeneration patients confirmed by magnetic resonance imaging and 126 healthy controls were enrolled in the current study. Radiological evaluation of the IDD was conducted using a 3.0-T magnetic resonance imaging scanner for entire lumbar vertebra region. Degeneration of intervertebral disk was assessed by Schneiderman criteria. Serum CCL3/MIP-1α levels were investigated using a sandwich enzyme-linked immunosorbent assay. The Visual Analog Scale scores and Oswestry Disability Index index were recorded for clinical severity. Results: Elevated concentrations of CCL3 in serum were found in IDD patients compared with asymptomatic volunteers. The case group included 49 IDD patients with grade 1, 42 with grade 2, and 41 with grade 3. Grade 3 and 2 had significantly higher CCL3 concentrations in serum compared with those with grade 1. The serum CCL3 levels were positively related to the degree of disk degeneration. In addition, the serum CCL3 levels also demonstrated a significant correlation with the clinical severity determined by Visual Analog Scale scores and Oswestry Disability Index index. Conclusion: Serum CCL3 may serve as a biomarker of IDD. Keywords: chemokine cytokine ligand 3, intervertebral disk degeneration, cross

  7. Reflectance Modeling

    Science.gov (United States)

    Smith, J. A.; Cooper, K.; Randolph, M.

    1984-01-01

    A classical description of the one dimensional radiative transfer treatment of vegetation canopies was completed and the results were tested against measured prairie (blue grama) and agricultural canopies (soybean). Phase functions are calculated in terms of directly measurable biophysical characteristics of the canopy medium. While the phase functions tend to exhibit backscattering anisotropy, their exact behavior is somewhat more complex and wavelength dependent. A Monte Carlo model was developed that treats soil surfaces with large periodic variations in three dimensions. A photon-ray tracing technology is used. Currently, the rough soil surface is described by analytic functions and appropriate geometric calculations performed. A bidirectional reflectance distribution function is calculated and, hence, available for other atmospheric or canopy reflectance models as a lower boundary condition. This technique is used together with an adding model to calculate several cases where Lambertian leaves possessing anisotropic leaf angle distributions yield non-Lambertian reflectance; similar behavior is exhibited for simulated soil surfaces.

  8. Reflective optics

    CERN Document Server

    Korsch, Dietrich

    1991-01-01

    This is the first book dedicated exclusively to all-reflective imaging systems. It is a teaching tool as well as a practical design tool for anyone who specializes in optics, particularly for those interested in telescopes, infrared, and grazing-incidence systems. The first part of the book describes a unified geometric optical theory of all-reflective imaging systems (from near-normal to grazing incidence) developed from basic principles. The second part discusses correction methods and a multitude of closed-form solutions of well-corrected systems, supplemented with many conventional and unc

  9. A REFLECTION

    African Journals Online (AJOL)

    Man has not been prodigiously provided for by nature; on account of it man ..... There was a 'cross' as the spiritual passed through the physical, a reaction took ... mind an idea of motion, movement, action and development within man and within .... of activity, that of grace, live and mercy but one must make move unto God ...

  10. Reflective Efficacy

    Directory of Open Access Journals (Sweden)

    Carla Bagnoli

    2018-04-01

    Full Text Available The purpose of this paper is to highlight some difficulties of Neil Sinhababu’s Humean theory of agency, which depend on his radically reductivist approach, rather than to his Humean sympathies. The argument is that Sinhababu’s theory builds upon a critique of reflective agency which is based on equivocation and misunderstandings of the Kantian approach. Ultimately, the objection is that his reductivist view is unequipped to address the rclassical problems of rational deliberation and agential authority.

  11. On Reflection

    DEFF Research Database (Denmark)

    Blasco, Maribel

    2012-01-01

    produces: that the self is accessible and transcendable, that reflexivity is universal across space and time, and that the self can act as its own remedial change agent or ‘inner consultant.’ I argue that because reflexivity is understood in many different ways, attention to definition is crucial, both...... on the concepts of selfhood that prevail and how notions of difference are constructed. First, I discuss how the dominant usages of reflexivity in intercultural education reflect and reproduce a Cartesian view of the self that shapes how ICC is conceptualized and taught. I discuss three assumptions that this view...

  12. Inspiring Reflections

    DEFF Research Database (Denmark)

    Muchie, Mammo

    2011-01-01

    A numberof Chris Freeman's colleagues were asked to reflect on what they thought describes his life and work in a few words. Some of the colleagues replied including former SPRU students that were taught or supervised by Chris Freeman. Their views on what they thought were Chris Freeman's defining...... life is not free from fluctuations, cycles, disruptions, crises and destructions both human and ecological. Innovation research ought to position itself to address environmental, financial and economic crises. The third is innovation research for development by addressing not only poverty erdaication...

  13. Reflective Writing

    DEFF Research Database (Denmark)

    Ahrenkiel Jørgensen, Andriette

    2016-01-01

    In Breve fra min Have (Letters from my Garden), the Swedish landscape architect, Sven-Ingvar Andersson, produces dialogues about his garden to a wide circle of friends, colleagues, deceased and still living acquaintances such as Karen Blixen, Gertrude Stein, C. Th. Sørensen, Albrecht Dürer, Peter...... Høeg etetera. The dialogues work as a tool of reflection in terms of providing opportunity to examine his own beliefs, to explore the possible reasons for engaging in a particular activity. On the basis of Sven-Ingvar Andersson’s book a teaching program at the Aarhus School of Architecture provides...

  14. Reflective Packaging

    Science.gov (United States)

    1994-01-01

    The aluminized polymer film used in spacecraft as a radiation barrier to protect both astronauts and delicate instruments has led to a number of spinoff applications. Among them are aluminized shipping bags, food cart covers and medical bags. Radiant Technologies purchases component materials and assembles a barrier made of layers of aluminized foil. The packaging reflects outside heat away from the product inside the container. The company is developing new aluminized lines, express mailers, large shipping bags, gel packs and insulated panels for the building industry.

  15. Neutron reflectivity

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available The specular neutron reflectivity is a technique enabling the measurement of neutron scattering length density profile perpendicular to the plane of a surface or an interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5 Å up 5000 Å. It is a scattering technique that averages information on the entire surface and it is therefore not possible to obtain information within the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons makes it particularly interesting in the fields of soft matter, biophysics and magnetic thin films. This course is a basic introduction to the technique and does not address the magnetic reflectivity. It is composed of three parts describing respectively its principle and its formalism, the experimental aspects of the method (spectrometers, samples and two examples related to the materials for energy.

  16. Reflected Glory

    Science.gov (United States)

    2011-02-01

    The nebula Messier 78 takes centre stage in this image taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile, while the stars powering the bright display take a backseat. The brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light. Igor Chekalin was the overall winner of ESO's Hidden Treasures 2010 astrophotography competition with his image of this stunning object. Messier 78 is a fine example of a reflection nebula. The ultraviolet radiation from the stars that illuminate it is not intense enough to ionise the gas to make it glow - its dust particles simply reflect the starlight that falls on them. Despite this, Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1350 light-years away in the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion's belt. This new image of Messier 78 from the MPG/ESO 2.2-metre telescope at the La Silla Observatory is based on data selected by Igor Chekalin in his winning entry to the Hidden Treasures competition [1]. The pale blue tint seen in the nebula in this picture is an accurate representation of its dominant colour. Blue hues are commonly seen in reflection nebulae because of the way the starlight is scattered by the tiny dust particles that they contain: the shorter wavelength of blue light is scattered more efficiently than the longer wavelength red light. This image contains many other striking features apart from the glowing nebula. A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed and are still buried deep in dust clouds. Two bright stars, HD 38563A and

  17. Quantum transport in graphene normal-metal superconductor- normal-metal structures

    Directory of Open Access Journals (Sweden)

    H. Mohammadpour

    2008-06-01

    Full Text Available  We study the transport of electrons in a graphene NSN structure in which two normal regions are connected by a superconducting strip of thickness d. Within Dirac-Bogoliubov-de Gennes equations we describe the transmission through the contact in terms of different scattering processes consisting of quasiparticle cotunneling, local and crossed Andreev reflections. Compared to a fully normal structure we show that the angular dependence of the transmission probability is significantly modified by the presence of superconducting correlations. This modifation can be explained in terms of the interplay between Andreev reflection and Klein tunneling of chiral quasiparticles. We further analyze the energy dependence of the resulting differential conductance of the structure. The subgap differential conductance shows features of Andreev reflection and cotunelling processes, which tends to the values of an NS structure for large ds. Above the gap, the differential conductance shows an oscillatory behavior with energy even at very large ds.

  18. Reflections on Conformal Spectra

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ0 of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ0 as well as for large Δ0. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function. (based on 1510.08772 with Kim & Ooguri). This seminar will be given via videolink

  19. Challenging Narcissus, or Reflecting on Reflecting.

    Science.gov (United States)

    Achilles, C. M.

    The concept of reflective practice and teaching people to be reflective practitioners is examined. The document begins with a look at professional knowledge according to three prominent professionals in the educational administration field: Schon, Schein, and Achilles. "Reflective" strategies that could be incorporated into courses and…

  20. The reflection seismology measurement method

    International Nuclear Information System (INIS)

    Sprecher, C.

    1987-01-01

    Even though data acquisition and data processing procedures have become more and more complex in recent decades, the end products of a reflection seismic survey have remained simple and illustrative. A seismic section resembles a geological cross-section and can be interpreted without in-depth knowledge provided that the basic principles behind the method are understood. This article attempts to convey some insight into the methodology without claiming to be scientifically exact or complete. (author)

  1. Nonlocal Cooper pair splitting in a pSn-junction

    NARCIS (Netherlands)

    Veldhorst, M.; Brinkman, Alexander

    2010-01-01

    Perfect Cooper pair splitting is proposed, based on crossed Andreev reflection (CAR) in a p-type semiconductor-superconductor-n-type semiconductor (pSn) junction. The ideal splitting is caused by the energy filtering that is enforced by the band structure of the electrodes. The pSn junction is

  2. A situated approach to VET students' reflection processes across boundaries

    DEFF Research Database (Denmark)

    Wegener, Charlotte

    2014-01-01

    The purpose of this paper is to illuminate the intersection between institutional requirements for reflection and students’ actual reflection initiatives in the social and health care education programmes. A situated perspective makes it possible to illuminate individuals’ commitment, curiosity a...... be enhanced. The paper adds to previous research on boundary crossing in vocational education and highlights the notion of visible reflection....

  3. Temperature-reflection I

    DEFF Research Database (Denmark)

    McGady, David A.

    2017-01-01

    -temperature path integrals for quantum field theories (QFTs) should be T-reflection invariant. Because multi-particle partition functions are equal to Euclidean path integrals for QFTs, we expect them to be T-reflection invariant. Single-particle partition functions though are often not invariant under T......In this paper, we revisit the claim that many partition functions are invariant under reflecting temperatures to negative values (T-reflection). The goal of this paper is to demarcate which partition functions should be invariant under T-reflection, and why. Our main claim is that finite...... that T-reflection is unrelated to time-reversal. Finally, we study the interplay between T-reflection and perturbation theory in the anharmonic harmonic oscillator in quantum mechanics and in Yang-Mills in four-dimensions. This is the first in a series of papers on temperature-reflections....

  4. Radar reflection off extensive air showers

    CERN Document Server

    Stasielak, J; Bertaina, M; Blümer, J; Chiavassa, A; Engel, R; Haungs, A; Huege, T; Kampert, K -H; Klages, H; Kleifges, M; Krömer, O; Ludwig, M; Mathys, S; Neunteufel, P; Pekala, J; Rautenberg, J; Riegel, M; Roth, M; Salamida, F; Schieler, H; Šmída, R; Unger, M; Weber, M; Werner, F; Wilczyński, H; Wochele, J

    2012-01-01

    We investigate the possibility of detecting extensive air showers by the radar technique. Considering a bistatic radar system and different shower geometries, we simulate reflection of radio waves off the static plasma produced by the shower in the air. Using the Thomson cross-section for radio wave reflection, we obtain the time evolution of the signal received by the antennas. The frequency upshift of the radar echo and the power received are studied to verify the feasibility of the radar detection technique.

  5. Liberating Moral Reflection

    Science.gov (United States)

    Horell, Harold D.

    2013-01-01

    The author argues that if we are to foster life-giving and liberating moral reflection, we must first liberate moral reflection from distortions; specifically, from the distorting effects of moral insensitivity, destructive moral relativism, and confusions resulting from a failure to understand the dynamics of moral reflection. The author proposes…

  6. Media for Reflection

    DEFF Research Database (Denmark)

    Knudsen, Morten

    2016-01-01

    This article develops the concept media for reflection in the interest of conceptualizing the interpretative frames that enable and limit reflection in management and leadership education. The concept ‘media for reflection’ allows us to conceptualize the social and cultural mediation of reflection...... without reducing reflection to an effect of the social structures and cultural norms in which it is embedded. Based on the developed theoretical framework, this article analyses how a renaissance ‘mirror for princes’ and contemporary research-based management education mediate reflection. The content...... of the mediations is analysed as well as the societal and organizational background. Furthermore, the means by which the two media enable and limit reflection in different ways is compared. Finally, the article discusses possible implications of the analysis in terms of management and leadership education....

  7. Principles of neutron reflection

    International Nuclear Information System (INIS)

    Felcher, G.P.

    1988-08-01

    Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs

  8. Storage array reflection considerations

    International Nuclear Information System (INIS)

    Haire, M.J.; Jordan, W.C.; Taylor, R.G.

    1997-01-01

    The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water-reflected (i.e. surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established

  9. Dissenting in Reflective Conversations

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Boulus, Nina

    2011-01-01

    Reflective monitoring of research practices is essential. However, we often lack formal training in the practices of doing action research, and descriptions of actual inquiry practice are seldom included in publications. Our aim is to provide a glimpse of self-reflective practices based on our...

  10. Self-Reflection

    DEFF Research Database (Denmark)

    Fausing, Bent

    2016-01-01

    will take a look at the establishing of the modern self and possibilities of self-reflection, too. My examples will be from the so-called dark-selfies and from a new selfie form, which merge the present with the previous progressing into the future. I will discuss the media reflections as loos and/or gain...

  11. Reflection: A Socratic approach.

    Science.gov (United States)

    Van Seggelen-Damen, Inge C M; Van Hezewijk, René; Helsdingen, Anne S; Wopereis, Iwan G J H

    2017-12-01

    Reflection is a fuzzy concept. In this article we reveal the paradoxes involved in studying the nature of reflection. Whereas some scholars emphasize its discursive nature, we go further and underline its resemblance to the self-biased dialogue Socrates had with the slave in Plato's Meno . The individual and internal nature of the reflection process creates difficulty for studying it validly and reliably. We focus on methodological issues and use Hans Linschoten's view of coupled systems to identify, analyze, and interpret empirical research on reflection. We argue that researchers and research participants can take on roles in several possible system couplings. Depending on who controls the manipulation of the stimulus, who controls the measuring instrument, who interprets the measurement and the response, different types of research questions can be answered. We conclude that reflection may be validly studied by combining different couplings of experimenter, manipulation, stimulus, participant, measurement, and response.

  12. Storage array reflection considerations

    International Nuclear Information System (INIS)

    Haire, M.J.; Jordan, W.C.; Taylor, R.G.

    1997-01-01

    The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water reflected (i.e., surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established. When evaluating arrays, it has become more common for analysts to use calculations to demonstrate the safety of the array configuration. In performing these calculations, the analyst has considerable freedom concerning the assumptions made for modeling the reflection of the array. Considerations are given for the physical layout of the array with little or no discussion (or demonstration) of what conditions are bounded by the assumed reflection conditions. For example, an array may be generically evaluated by placing it in a corner of a room in which the opposing walls are far away. Typically, it is believed that complete flooding of the room is incredible, so the array is evaluated for various levels of water mist interspersed among array containers. This paper discusses some assumptions that are made regarding storage array reflection

  13. The Reflective Foundation

    DEFF Research Database (Denmark)

    Lunde Jørgensen, Ida

    Private foundations and cultural philanthropy by élites is viewed with increasing skepticism in recent years, begging the question of the extent to which foundations reflect on their role vis a vis wider societal norms. Through the prism of the New Carlsberg Foundation, financed by the brewery...... Carlsberg A/S, the paper seeks to elucidate the way in which one culturally significant foundation from Denmark has reflected on - and legitimated - its work and investments at critical moments in the past decades. The paper indicates a foundation with a high degree of reflection on the wider societal...

  14. Active Multispectral Band Selection and Reflectance Measurement System

    National Research Council Canada - National Science Library

    Rennich, Bradley

    1999-01-01

    .... To aid in the selection of these bands, a novel multispectral band selection technique is presented based on the cross-correlation of the material class reflectance spectra over a wavelength range of 1 - 5 microns...

  15. Seasonal soybean crop reflectance

    Science.gov (United States)

    Lemaster, E. W. (Principal Investigator); Chance, J. E.

    1983-01-01

    Data are presented from field measurements of 1980 including 5 acquisitions of handheld radiometer reflectance measurements, 7 complete sets of parameters for implementing the Suits mode, and other biophysical parameters to characterize the soybean canopy. LANDSAT calculations on the simulated Brazilian soybean reflectance are included along with data collected during the summer and fall on 1981 on soybean single leaf optical parameters for three irrigation treatments. Tests of the Suits vegetative canopy reflectance model for the full hemisphere of observer directions as well as the nadir direction show moderate agreement for the visible channels of the MSS and poor agreement in the near infrared channel. Temporal changes in the spectral characteristics of the single leaves were seen to occur as a function of maturity which demonstrates that the absorptance of a soybean single leaf is more a function of thetransmittancee characteristics than the seasonally consistent single leaf reflectance.

  16. Selectively reflective transparent sheets

    Science.gov (United States)

    Waché, Rémi; Florescu, Marian; Sweeney, Stephen J.; Clowes, Steven K.

    2015-08-01

    We investigate the possibility to selectively reflect certain wavelengths while maintaining the optical properties on other spectral ranges. This is of particular interest for transparent materials, which for specific applications may require high reflectivity at pre-determined frequencies. Although there exist currently techniques such as coatings to produce selective reflection, this work focuses on new approaches for mass production of polyethylene sheets which incorporate either additives or surface patterning for selective reflection between 8 to 13 μ m. Typical additives used to produce a greenhouse effect in plastics include particles such as clays, silica or hydroxide materials. However, the absorption of thermal radiation is less efficient than the decrease of emissivity as it can be compared with the inclusion of Lambertian materials. Photonic band gap engineering by the periodic structuring of metamaterials is known in nature for producing the vivid bright colors in certain organisms via strong wavelength-selective reflection. Research to artificially engineer such structures has mainly focused on wavelengths in the visible and near infrared. However few studies to date have been carried out to investigate the properties of metastructures in the mid infrared range even though the patterning of microstructure is easier to achieve. We present preliminary results on the diffuse reflectivity using FDTD simulations and analyze the technical feasibility of these approaches.

  17. Thoughts on Reflection (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2010-06-01

    Full Text Available There has been some acknowledgement in the published literature that reflection is a crucial element of the evidence based library and information practice (EBLIP model we have adopted (Booth 2004, 2006; Grant 2007; Helliwell 2007. As we work through a problem and try to incorporate the best available evidence into our decision making, reflection is required at several stages, including the very identification of the problem through to our assessment of the process itself and what we have learned in order to inform future practice. However, reflection and reflective writing have not fully been integrated into the process we espouse, and very little has been done to look more closely at this element of the model and how it can be integrated into professional learning.In a recently published research article, Sen (2010 confirms the relationship between reflection and several aspects of professional practice. These include critical review and decision making, two aspects that are tied closely to the evidence based process. Sen notes: Students were more likely to show evidence of learning, self‐development, the ability to review issues crucially, awareness of their own mental functions, ability to make decision [sic] and being empowered when they had mastered the art of reflective practice and the more deeply analytical reflective writing. (p.84 EBLIP (the journal tries to incorporate elements of reflection within the articles we publish. While we clearly believe in the need for our profession to do quality research and publish that research so that it can be accessible to practitioners, we also know that research cannot be looked at in isolation. Our evidence summaries are one way of reflecting critically on previously published research, and in the same vein, our classics bring older research studies back to the foreground. This work needs to continue to be discussed and looked at for its impact on our profession.More directly, the Using

  18. Creation, Identity and Reflection

    Directory of Open Access Journals (Sweden)

    Alina Beatrice Cheşcă

    2015-05-01

    Full Text Available The paper “Creation, Identity and Reflection” approaches the identification in the “mirror” of reality with creation, in other words seeking the authors’ identity in the reflected images. Reflection means attempting to find oneself, the mirror being the main principle of creation. Many characters become interesting only when they step into the world beyond the mirror, when their faces are doubled by the other self or when their selves are returned by other characters. The narcissistic concept of the mirror, i.e. the reflection in the mirror and the representation of the mirror itself, is a recurrent one in literature, but the reflection of the self which is not the self (as it is a reflection does not necessarily appear in a mirror or in a photograph or portrait. Sometimes, the not-self is returned to the self by another person or character. As far as Oscar Wilde’s theories are concerned, the main idea is that people are interesting for their masks, not for their inner nature. What Wilde calls “inner nature” is the characters’ un-reflected self and the mask is the reflection, the self in the mirror. Some characters’ relationships develop within a fiction that they dramatically try to preserve and protect with the risk of suffering. They refuse to take off the masks which define them in the others’ minds and hearts; the narcissistic individuals (both artists and characters seek and love their own image which they project upon facts, thus creating a fictive realm.

  19. Radar reflection off extensive air showers

    Directory of Open Access Journals (Sweden)

    Werner F.

    2013-06-01

    Full Text Available We investigate the possibility of detecting extensive air showers by the radar technique. Considering a bistatic radar system and different shower geometries, we simulate reflection of radio waves off the static plasma produced by the shower in the air. Using the Thomson cross-section for radio wave reflection, we obtain the time evolution of the signal received by the antennas. The frequency upshift of the radar echo and the power received are studied to verify the feasibility of the radar detection technique.

  20. Biology Reflective Assessment Curriculum

    Science.gov (United States)

    Bayley, Cheryl Ann

    Often students and educators view assessments as an obligation and finality for a unit. In the current climate of high-stakes testing and accountability, the balance of time, resources and emphasis on students' scores related to assessment have been slanted considerably toward the summative side. This tension between assessment for accountability and assessment to inform teaching strains instruction and educators' ability to use that information to design learning opportunities that help students develop deeper conceptual understanding. A substantive body of research indicates that formative and reflective assessment can significantly improve student learning. Biology Reflective Assessment Curriculum (BRAC) examines support provided for high school science students through assessment practices. This investigation incorporates the usage of reflective assessments as a guiding practice for differentiated instruction and student choice. Reflective assessment is a metacognitive strategy that promotes self-monitoring and evaluation. The goals of the curriculum are to promote self-efficacy and conceptual understanding in students learning biology through developing their metacognitive awareness. BRAC was implemented in a high school biology classroom. Data from assessments, metacognitive surveys, self-efficacy surveys, reflective journals, student work, a culminating task and field notes were used to evaluate the effectiveness of the curriculum. The results suggest that students who develop their metacognitive skills developed a deeper conceptual understanding and improved feelings of self-efficacy when they were engaged in a reflective assessment unit embedded with student choice. BRAC is a tool for teachers to use assessments to assist students in becoming metacognitive and to guide student choice in learning opportunities.

  1. Retrieval of reflections from seismic background?noise measurements

    NARCIS (Netherlands)

    Draganov, D.S.; Wapenaar, K.; Mulder, W.; Singer, J.; Verdel, A.

    2007-01-01

    The retrieval of the earth's reflection response from cross?correlations of seismic noise recordings can provide valuable information, which may otherwise not be available due to limited spatial distribution of seismic sources. We cross?correlated ten hours of seismic background?noise data acquired

  2. Self-Reflection

    DEFF Research Database (Denmark)

    Fausing, Bent

    2018-01-01

    Reflecting has a double meaning, mirroring and thinking. The seminar will investigate how these two meanings intervene in each other. As we perceive we are already in pre-refectory state, and thinking involves a lot of not only thoughts, but also of senses and sensing, wherefrom our thoughts star...

  3. Worship, Reflection, Empirical Research

    OpenAIRE

    Ding Dong,

    2012-01-01

    In my youth, I was a worshipper of Mao Zedong. From the latter stage of the Mao Era to the early years of Reform and Opening, I began to reflect on Mao and the Communist Revolution he launched. In recent years I’ve devoted myself to empirical historical research on Mao, seeking the truth about Mao and China’s modern history.

  4. Reflections on 21 years

    International Nuclear Information System (INIS)

    Eklund, S.; Mandel, H.; Teller, E.

    1977-01-01

    Personal reflections after twenty one years of nuclear power are presented by a number of those who were international figures in the nuclear energy field during that period. Lessons learnt, achievements, prospects and predictions for the future are discussed in eleven brief surveys. (U.K.)

  5. Reflection by Porro Prisms

    Science.gov (United States)

    Greenslade, Thomas B.

    2010-04-01

    Students all know that reflection from a plane mirror produces an image that is reversed right to left and so cannot be read by anyone but Leonardo da Vinci, who kept his notes in mirror writing. A useful counter-example is the Porro prism, which produces an image that is not reversed.

  6. Value reflected health education

    DEFF Research Database (Denmark)

    Wistoft, Karen; Nordentoft, Helle Merete

    2011-01-01

    This article examines the impact of a value-reflected approach in health education by demonstrating the nature of professional competence development connected to this approach. It is based on findings from two three-year health educational development projects carried out by school health nurses...... develop pedagogical competences in health education improving school childrens’ health....

  7. Reflection on Political Representation

    DEFF Research Database (Denmark)

    Kusche, Isabel

    2017-01-01

    This article compares how Members of Parliament in the United Kingdom and Ireland reflect on constituency service as an aspect of political representation. It differs from existing research on the constituency role of MPs in two regards. First, it approaches the question from a sociological viewp...

  8. Onward: Reflections on Mentoring

    Science.gov (United States)

    Williams, Kimberley Buster

    2018-01-01

    The author has been blessed with great mentors throughout her career. When she was invited to participate in the Leadership University of Mary Washington (UMW), a mentoring program at her institution, she did not hesitate to say yes. In this article, the author shares her reflections on mentoring.

  9. Interferometric reflection moire

    Science.gov (United States)

    Sciammarella, Cesar A.; Combell, Olivier

    1995-06-01

    A new reflection moire technique is introduced in this paper. The basic equations that relate the measurement of slopes to the basic geometric and optical parameters of the system are derived. The sensitivity and accuracy of the method are discussed. Examples of application to the study of silicon wafers and electronic chips are given.

  10. Reflection on robotic intelligence

    NARCIS (Netherlands)

    Bartneck, C.

    2006-01-01

    This paper reflects on the development or robots, both their physical shape as well as their intelligence. The later strongly depends on the progress made in the artificial intelligence (AI) community which does not yet provide the models and tools necessary to create intelligent robots. It is time

  11. Reflections on "La Esperanza"

    Science.gov (United States)

    Cortez, Anita

    2007-01-01

    The author was recently asked to reflect on her "educational journey." As far as she can remember she has been hungry to learn. A friend once described her as having "hambres atrasadas," which he described as a kind of "hunger nipping at her heels." It goes back, of course, to her parents: Her father's and her early…

  12. Reflecting on Writing Autobiography

    Science.gov (United States)

    Begg, Andy

    2011-01-01

    The following reflections relate to the reasons for and an approach to an autobiographic task, the notions that underpin it, and some thoughts about the quality and value of such a project. The focus was on the ways one views curriculum change over time; and the intention was to provide an example that others may sense as either familiar or at…

  13. Reflections on the Field.

    Science.gov (United States)

    Kauffman, James M.

    2003-01-01

    Reflections on the field of special education offer six ideas: (1) the value of science; (2) the continuing value of separate and special education for some students; (3) the continuing importance of prevention; (4) the importance of academic instruction; (5) the importance of social justice for the poor; and (6) a renewed emphasis on human…

  14. Reflections, 15 Years Later

    Science.gov (United States)

    Knox, George

    2016-01-01

    George Knox reflects on his 15-year career as president of Labette Community College in Parsons, Kansas. Knox writes that, as a first-time president coming into a brand new system, he was very fortunate to have many seasoned presidents and mentors in Kansas and from the American Association of Community Colleges' (AACC) Presidents Academy. He says…

  15. Reflections on Visualization in Cross-Cultural Design

    DEFF Research Database (Denmark)

    Rodil, Kasper

    2015-01-01

    in Namibia. I aim to show how conversations around visualiza-tions can increase a designer’s sensitivity to others’ perspectives, support mutual learn-ing, and trigger the engagement and criticism that are vital for co-design. Between the end of 2010 and 2013, I undertook eight research visits of 3 to 7 days...... a home there. Through participatory action research in Erindiroukambe, which developed since the end of 2008, we have engaged with a group of elders and run various design activities, which include amongst other activities four different digital prototypes, running on laptop and tablet computers. We have...

  16. Youth Reflect on Hitler: A Cross-National Study.

    Science.gov (United States)

    McRoy, James J.

    1985-01-01

    A content analysis of essays written by students from Great Britain and the United States on the topic "What I have heard about Adolf Hitler" showed that today's youth have only a very superficial knowledge about the events surrounding Hitler and Nazism. (RM)

  17. Cross-cultural medical education: Using narratives to reflect on ...

    African Journals Online (AJOL)

    Introduction. Educating students in a multi-cultural society is a challenge as teachers, students and the community they serve all tend to represent various social groups. Skills alone are not adequate for competency in understanding cultural aspects of consultations. A combination of knowledge, skills and attitude is the most ...

  18. Cross-Cultural Mirrors: Two-Way Reflections

    Directory of Open Access Journals (Sweden)

    Mimi Yang

    2010-10-01

    Full Text Available Ronald Takaki starts his milestone work 'A Different Mirror: A History of Multicultural America 'with an anecdote that is not difficult for those who have East Asian heritages to relate.

  19. Reflections on Intellectual Hybridity

    Directory of Open Access Journals (Sweden)

    Kimala Price

    2012-05-01

    Full Text Available Drawing from the growing literature on interdisciplinarity and my own experiences as an intellectual hybrid, I discuss the personal and institutional challenges inherent in crossing disciplinary boundaries in the academy. I argue that boundary crossing is a natural occurrence and that the issue of (interdisciplinarity is a matter of degree and of determining who gets to define the boundaries. Defining boundaries is not merely an intellectual enterprise, but also a political act that delineates what is, or is not, legitimate scholarship. This issue is especially salient to women's and gender studies during times of economic distress and educational budget cuts.

  20. CHALLENGES IN CROSS CULTURAL ADVERTISING

    OpenAIRE

    Yuni Retnowati

    2016-01-01

    At first, marketing practitioners and academics consider standardized approaches to marketing and advertising strategies in globalization, and then some studies proved that the standardization of advertising across culture is not valid. Therefore, cross cultural advertising takes local culture into account when conveying messages in advertisements. Cross cultural understanding is very important in order to produce successful localized advertising that would reflect the cultural values and nor...

  1. Being a reflective teacher——reflection on group management

    Institute of Scientific and Technical Information of China (English)

    Pan; Lehui

    2015-01-01

    <正>Introduction According to Pollard and Triggs(1997),reflective teaching is a process through which the capacity to make such professional judgments can be developed and maintained.Then what is a reflective teacher?Reflective teacher is someone who reflects systematically on her practice in a constant attempt to improve

  2. Ethical reflection and psychotherapy.

    Science.gov (United States)

    Vyskocilová, Jana; Prasko, Jan

    2013-01-01

    Theories of ethics and ethical reflection may be applied to both theory and practice in psychotherapy. There is a natural affinity between ethics and psychotherapy. Psychotherapy practice is concerned with human problems, dilemmas and emotions related to both one's own and other people's values. Ethics is also concerned with dilemmas in human thinking and with how these dilemmas reflect other individuals' values. Philosophical reflection itself is not a sufficient basis for the ethics of psychotherapy but it may aid in exploring attitudes related to psychotherapy, psychiatry and health care. PubMed, Web of Science and Scopus databases were searched for articles containing the keywords "psychotherapy", "ethics", "therapeutic relationship" and "supervision". The search was conducted by repeating the terms in various combinations without language or time restrictions. Also included were data from monographs cited in reviews. The resulting text is a review with conclusions concerning ethical aspects of psychotherapy. The ability to behave altruistically, sense for justice and reciprocity and mutual help are likely to be genetically determined as dispositions to be later developed by upbringing or to be formed or deformed by upbringing. Early experiences lead to formation of ethical attitudes which are internalized and then applied to both one's own and other people's behavior. Altruistic behavior has a strong impact on an individual's health and its acceptance may positively influence the pathophysiological mechanisms underlying numerous diseases. Ethical theory and reflection, however, may be applied to both theory and practice of psychotherapy in a conscious, targeted and thoughtful manner. In everyday practice, psychotherapists and organizations must necessarily deal with conscious conflicts between therapeutic possibilities, clients' wishes, their own as well as clients' ideas and the real world. Understanding one's own motives in therapy is one of the aims of a

  3. Reflections on Culture.

    Science.gov (United States)

    Fox, Lisette

    1999-01-01

    Examines aspects of cross-cultural studies, delineates a concept of culture, explores the interplay of culture and ethics, and analyzes the shifting cultural and economic values as issues that either the economists or the humanists will deal with under the banner of the future global village. (Author/VWL)

  4. Bragg reflection program

    International Nuclear Information System (INIS)

    Lynn, J.W.

    This user's guide to the Bragg Reflection Program (BRP) is in the nature of an informal report. The general purpose of BRP is to scan a series of Bragg reflections automatically in order to obtain profiles and integrated intensities. The program is used in conjunction with the SUPERVISOR and READ packages, and the procedures for using it are similar to those for the Triple-Axis Control program. All the general features of the system, SUPERVISOR and READ packages as described in the Spectrometer Control Systems User's Guide are preserved. The presentation assumes that the reader is familiar with these. Sections are given on the READ package, execution and use, error messages, and output. A few sample problems are shown. (1 figure) (U.S.)

  5. Reflections on Active Networking

    Science.gov (United States)

    2005-01-01

    with a Software Switch for Active Networks ”. We had initially called the project “ SoftSwitch ”, but after some concerns David Farber raised that this...Reflections on Active Networking Jonathan M. Smith CIS Department, University of Pennsylvania jms@cis.upenn.edu Abstract Interactions among...telecommunications networks , computers, and other peripheral devices have been of interest since the earliest distributed computing systems. A key

  6. Clinical linguistics: conversational reflections.

    Science.gov (United States)

    Crystal, David

    2013-04-01

    This is a report of the main points I made in an informal "conversation" with Paul Fletcher and the audience at the 14th ICPLA conference in Cork. The observations arose randomly, as part of an unstructured 1-h Q&A, so they do not provide a systematic account of the subject, but simply reflect the issues which were raised by the conference participants during that time.

  7. Superradiance or total reflection?

    CERN Document Server

    László, András

    2014-01-01

    Numerical evolution of massless scalar fields on Kerr background is studied. The initial data specifications are chosen to have compact support separated from the ergoregion and to yield nearly monochromatic incident wave packets. The initial data is also tuned to maximize the effect of superradiance. Evidences are shown indicating that instead of the anticipated energy extraction from black hole the incident radiation fail to reach the ergoregion rather it suffers a nearly perfect reflection.

  8. Polarizer reflectivity variations

    International Nuclear Information System (INIS)

    Ozarski, R.G.; Prior, J.

    1980-01-01

    On Shiva the beam energy along the chain is monitored using available reflections and/or transmission through beam steering, splitting, and polarizing optics without the intrusion of any additional glass for diagnostics. On the preamp table the diagnostic signal is obtained from the signal transmitted through turning mirrors. At the input of each chain the signal is obtained from the transmission through one of the mirrors used for the chain input alignment sensor (CHIP). At the chain output the transmission through the final turning mirror is used. These diagnostics have proved stable and reliable. However, one of the prime diagnostic locations is at the output of the beta rod. The energy at this location is measured by collecting small reflections from the last polarizer surface of the beta Pockels cell polarizer package. Unfortunately, calibration of this diagnostic has varied randomly, seldom remaining stable for a week or more. The cause of this fluctuation has been investigated for the past year and'it has been discovered that polarizer reflectivity varies with humidity. This report will deal with the possible causes that were investigated, the evidence that humidity is causing the variation, and the associated mechanism

  9. Reflection Revisited: The Class Collage

    Science.gov (United States)

    Sommers, Jeff

    2011-01-01

    Through the regular use of what Donald Schon has termed reflection-in-action and reflection-on-action, students can learn to improve their "reflection-in-presentation," in Kathleen Blake Yancey's term. Students are often asked to do this type of reflection-in-presentation as a capstone to first-year or basic writing courses. However, a number of…

  10. Reflection as Self-Assessment

    Science.gov (United States)

    Pappas, Marjorie L.

    2010-01-01

    In this article, the author discusses how reflection can be used as self-assessment. Reflection involves not only thinking about a learning experience, but also questioning parts of the experience. Reflection is thinking about what one knows from the learning experience, what one might do differently the next time. Reflection is wondering about…

  11. Seismic reflection imaging, accounting for primary and multiple reflections

    Science.gov (United States)

    Wapenaar, Kees; van der Neut, Joost; Thorbecke, Jan; Broggini, Filippo; Slob, Evert; Snieder, Roel

    2015-04-01

    Imaging of seismic reflection data is usually based on the assumption that the seismic response consists of primary reflections only. Multiple reflections, i.e. waves that have reflected more than once, are treated as primaries and are imaged at wrong positions. There are two classes of multiple reflections, which we will call surface-related multiples and internal multiples. Surface-related multiples are those multiples that contain at least one reflection at the earth's surface, whereas internal multiples consist of waves that have reflected only at subsurface interfaces. Surface-related multiples are the strongest, but also relatively easy to deal with because the reflecting boundary (the earth's surface) is known. Internal multiples constitute a much more difficult problem for seismic imaging, because the positions and properties of the reflecting interfaces are not known. We are developing reflection imaging methodology which deals with internal multiples. Starting with the Marchenko equation for 1D inverse scattering problems, we derived 3D Marchenko-type equations, which relate reflection data at the surface to Green's functions between virtual sources anywhere in the subsurface and receivers at the surface. Based on these equations, we derived an iterative scheme by which these Green's functions can be retrieved from the reflection data at the surface. This iterative scheme requires an estimate of the direct wave of the Green's functions in a background medium. Note that this is precisely the same information that is also required by standard reflection imaging schemes. However, unlike in standard imaging, our iterative Marchenko scheme retrieves the multiple reflections of the Green's functions from the reflection data at the surface. For this, no knowledge of the positions and properties of the reflecting interfaces is required. Once the full Green's functions are retrieved, reflection imaging can be carried out by which the primaries and multiples are

  12. Chiral Majorana fermion modes regulated by a scanning tunneling microscope tip

    Science.gov (United States)

    Zhou, Yan-Feng; Hou, Zhe; Zhang, Ying-Tao; Sun, Qing-Feng

    2018-03-01

    The Majorana fermion can be described by a real wave function with only two phases (zero and π ) which provide a controllable degree of freedom. We propose a strategy to regulate the phase of the chiral Majorana state by coupling with a scanning tunneling microscope tip in a system consisting of a quantum anomalous Hall insulator coupled with a superconductor. With the change in the chemical potential, the chiral Majorana state can be tuned alternately between zero and π , in which the perfect normal tunneling and perfect crossed Andreev reflection appear, respectively. The perfect crossed Andreev reflection, by which a Cooper pair can be split into two electrons going into different terminals completely, leads to a pumping current and distinct quantized resistances. These findings may provide a signature of Majorana fermions and pave a feasible avenue to regulate the phase of the Majorana state.

  13. Coupling spin qubits via superconductors

    DEFF Research Database (Denmark)

    Leijnse, Martin; Flensberg, Karsten

    2013-01-01

    We show how superconductors can be used to couple, initialize, and read out spatially separated spin qubits. When two single-electron quantum dots are tunnel coupled to the same superconductor, the singlet component of the two-electron state partially leaks into the superconductor via crossed...... Andreev reflection. This induces a gate-controlled singlet-triplet splitting which, with an appropriate superconductor geometry, remains large for dot separations within the superconducting coherence length. Furthermore, we show that when two double-dot singlet-triplet qubits are tunnel coupled...... to a superconductor with finite charging energy, crossed Andreev reflection enables a strong two-qubit coupling over distances much larger than the coherence length....

  14. A fiberoptic reflection oximeter.

    Science.gov (United States)

    Landsman, M L; Knop, N; Kwant, G; Mook, G A; Zijlstra, W G

    1978-03-20

    A catheter tip oximeter is described consisting of a cardiac catheter containing optical fibers, and incandescent light source, a light detection unit and a processing unit. Half of the optical fibers guide the light to the blood at the tip of the catheter, the other half the backscattered (reflected) light to the detection unit. The detection unit contains a dichroic mirror, transmitting most of the light with lambda less than 800 nm and reflecting most of the light with lambda greater than 900 nm, thus splitting the light into two beams. These pass through interference filters with nominal wavelengths of 640 and 920 nm respectively, and are focused on silicium barrier layer photocells. The photocell signals are amplified and fed into a divider giving the ratio of measuring (R640) and compensating (R920) photocell output. The relationship between log R640/R920 and oxygen saturation is represented by a slightly curved line. The relation may be linearized by subtracting a constant voltage from the divided output before taking the logarithm. The slope of the calibration line is dependent on the total haemoglobin concentration. Nonetheless an average calibration line can be used between 70 and 100% oxygen saturation. For 78 measurements of pig blood samples in this range (haemoglobin concentration between 96 and 161 g.1(-1)), the standard deviation of the difference between the fiberoptic oximeter and a Radiometer OSM1 oxygen saturation meter was 1.9% saturation, for 152 samples over the entire saturation range the standard deviation of the difference was 3.1% saturation. The influence of the flow velocity of blood on the light reflection depends on wavelength as well as on oxygen saturation. Therefore, complete compensation for the flow effect is not possible by simple means.

  15. Reflections on preventive medicine.

    Science.gov (United States)

    Miettinen, Olli S

    2014-10-01

    Having thought much about medicine in my career-long effort to understand it and the research for its advancement, I have come to views rather different form the now-prevailing ones in respect to what preventive medicine is about; what epidemiology is in relation to preventive medicine; what distinguishes preventive medicine in preventive healthcare at large; the relation of preventive medicine to public health; the concept of health promotion; and also the core principles of preventive medicine. All of these views I set forth in this article, for the readers' critical reflection. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Stream Crossings

    Data.gov (United States)

    Vermont Center for Geographic Information — Physical measurements and attributes of stream crossing structures and adjacent stream reaches which are used to provide a relative rating of aquatic organism...

  17. Matter reflects Antimatter

    CERN Document Server

    Bianconi, A.; Cristiano, A.; Leali, M.; Lodi Rizzini, E.; Venturelli, L.; Zurlo, N.

    2008-01-01

    It is common belief that the interaction between antimatter and ordinary solid matter is dominated by annihilation. However, non-destructive processes may play a relevant role too. One century ago E. Rutherford wrote about the "diffuse reflection" of alpha and beta particles by thin layers of different metals: "The observations ... of Geiger and Marsden on the scattering of alpha rays indicate that some of the alpha particles must suffer a deflexion of more than a right angle at a single encounter.... It will be shown that the main deductions from the theory are independent of whether the central charge is supposed to be positive or negative". Although the theory of electromagnetic scattering is in first approximation independent of the relative sign of the colliding particles, in the case where projectile antiprotons are shot against a wall of solid matter the Rutherford diffuse reflection mechanism competes with the annihilation process. So it is not obvious at all that a relevant part of an antiproton beam...

  18. Reflection, Interrogatory, Provocation

    International Nuclear Information System (INIS)

    Carnes, W.E.

    2016-01-01

    This invited paper advances a framing context for considering next steps in HOF and organizational culture in light of the presentations and discussions that occur during the conference. Many of the contributions during the conference will represent results of scholarly research, structured investigations, or formal organizational improvement efforts. This contribution is intended as informal reflection by a 40-year nuclear veteran on themes from other presentations considering questions such as: ''Where do we think we are?, Are we better off as an industry based on what we have done?, Where do we think we need to go?, What do we think we need to do?, and, Why do we think these things?'' Our coming together on this occasion marks 30 years since the publication of INSAG-l. As we reflect on the past, perhaps it is time to pose a series of questions. Are we sustainers of a mature technology that is in some places declining and being replaced by other energy sources? If we consider nuclear a mature technology, should we focus most on operational excellence with renewed attention to managing the unexpected? Or, is innovation still a vital part of our industry?

  19. Radar cross section

    CERN Document Server

    Knott, Gene; Tuley, Michael

    2004-01-01

    This is the second edition of the first and foremost book on this subject for self-study, training, and course work. Radar cross section (RCS) is a comparison of two radar signal strengths. One is the strength of the radar beam sweeping over a target, the other is the strength of the reflected echo sensed by the receiver. This book shows how the RCS ?gauge? can be predicted for theoretical objects and how it can be measured for real targets. Predicting RCS is not easy, even for simple objects like spheres or cylinders, but this book explains the two ?exact? forms of theory so well that even a

  20. Reflection and Non-Reflection of Particle Wavepackets

    Science.gov (United States)

    Cox, Timothy; Lekner, John

    2008-01-01

    Exact closed-form solutions of the time-dependent Schrodinger equation are obtained, describing the propagation of wavepackets in the neighbourhood of a potential. Examples given include zero reflection, total reflection and partial reflection of the wavepacket, for the sech[superscript 2]x/a, 1/x[superscript 2] and delta(x) potentials,…

  1. Reflecting Contemporary Design Research

    DEFF Research Database (Denmark)

    Engholm, Ida

    2017-01-01

    In recent years, design research has been the object of growing attention in universities and academies throughout the world. The present paper addresses the heterogeneous character of design research and the current need for reflection on the various approaches and interests. For this purpose......, the paper follows two steps. First, it proposes a categorization of the field in the form of a position model. The paper’s underlying assumption is that design research as a discipline exists in many different forms that cannot necessarily be brought together under one common academic research tradition......; instead it is necessary to attempt to define the field in order to initiate discussions about what constitutes the various research bases for design. Second, the paper discusses the implication for future design research when it is an interdisciplinary field that involves many disciplines, mindsets...

  2. The Reflective Methodologists

    DEFF Research Database (Denmark)

    Kjær, Bjørg

    2013-01-01

    In recent years, a focus on inclusion and vulnerable children has reignited discussions about the quality of pedagogical work. It has also initiated processes of change that have challenged the Danish kindergarten tradition and the identity of the pedagogue in a number of different ways. In this ......In recent years, a focus on inclusion and vulnerable children has reignited discussions about the quality of pedagogical work. It has also initiated processes of change that have challenged the Danish kindergarten tradition and the identity of the pedagogue in a number of different ways...... in which the practical sense and tacit knowledge are related to questions of power and social actors’ strategies for positioning themselves within a social space. This demands a particular focus on the historical effect of the concept of ‘the reflective practitioner’ as a symbolic marker of identity...

  3. Reflections on SLAP

    International Nuclear Information System (INIS)

    Cooke, Roger

    1997-01-01

    The SLAP data bases represent a major step forward in the reliability analysis of passive components. The present reflections are motivated by draft documentation for SLAP and have profited greatly from discussions with the SLAP team. We collect a number of remarks and suggestions: The use of event and failure fields to organize the data seems sensible and feasible, from a data analysis viewpoint. Influence factors, i. e. environmental influences which are affected by plant operations, are clearly important yet very difficult to accommodate in any straightforward data analysis methodology. We would welcome a serious effort to estimate the exposure in the various exposure cells. These estimates would not be based on failure records, but on knowledge of plant design and operations. Quantitative expert judgement might be a viable alternative to a massive review of all plants in the SLAP data base

  4. Reflections on academic video

    Directory of Open Access Journals (Sweden)

    Thommy Eriksson

    2012-11-01

    Full Text Available As academics we study, research and teach audiovisual media, yet rarely disseminate and mediate through it. Today, developments in production technologies have enabled academic researchers to create videos and mediate audiovisually. In academia it is taken for granted that everyone can write a text. Is it now time to assume that everyone can make a video essay? Using the online journal of academic videos Audiovisual Thinking and the videos published in it as a case study, this article seeks to reflect on the emergence and legacy of academic audiovisual dissemination. Anchoring academic video and audiovisual dissemination of knowledge in two critical traditions, documentary theory and semiotics, we will argue that academic video is in fact already present in a variety of academic disciplines, and that academic audiovisual essays are bringing trends and developments that have long been part of academic discourse to their logical conclusion.

  5. Reflections on Student Persistence

    Directory of Open Access Journals (Sweden)

    Vincent Tinto

    2017-07-01

    Full Text Available The Feature for this issue Reflections on Student Persistence has been prepared by Professor Vincent Tinto, Distinguished University Professor Emeritus at Syracuse University, United States of America (USA and a longtime friend and supporter of STARS. Vincent explores the case for motivation to be considered as a significant aspect of the tertiary student psyche by drawing on theoretical frameworks, research and practical experiences related to the issue. He synthesises this extensive, detailed, rich but often somewhat impenetrable data into a trilogy of clear and credible key dimensions of the motivation construct student self efficacy, sense of belonging and perceived value of the curriculum. This interpretation of the literature is a personal but informed reflection and is a timely piece which highlights the breadth and profundity of the presentations at this year's conference in Adelaide, Australia where students in all their diversity are central to our focus on enhancing the student experience. In this opening article, Vincent refers directly to the STARS papers selected for this Conference issue of the Journal which also address the importance of student persistence, self-efficacy and building the sense of belonging within their own institutional communities (Fernandes, Ford, Rayner & Pretorius; Kahu, Nelson, & Picton; McFarlane, Spes-Skrbis & Taib; Naylor; Smallhorn. Echoing his position on social justice and his advocacy for underserved students, Vincent reminds us that educational equity gaps still exist, and he encourages us to see the issue of persistence through the eyes of the students to support their perseverance and completion and thereby help reduce educational disadvantage.

  6. Multiple order reflections in crystal neutron monochromators

    International Nuclear Information System (INIS)

    Fulfaro, R.

    1976-01-01

    A study of the higher order reflections in neutron crystal monochromators was made in order to obtain, for the IEA single crystal spectrometer, the operation range of 1,0eV to 0,01eV. Two crystals were studied, an Al(III) near 1,0eV and a Ge(III) in lower energies. For the Ge(III) case the higher order contaminations in the reflected beam were determined using as standard the gold total neutron cross section and performing the crystal reflectivity calculation for several orders of reflection. The knowledge of the contamination for each order as a function of neutron wavelength allows the optimization of the filter thickness in order to avoid higher order neutrons. The Ge(III) crystal was used because its second order reflections are theoretically forbidden, giving an advantage on other crystals, since measurements can be made until 0.02eV directly without filters. In the energy range 0.02 to 0.01eV, order contaminations higher than the second are present, therefore, either quartz filters are employed or calculated corrections are applied to the experimental data. The Al(III) crystal was used in order to estimate the second order contamination effect, in the iridium resonance measurements, at E 0 = 0.654eV. In that region, approximations can be made and it was not necessary to make the crystal reflectivity calculation for the filters thickness optimization. Since only the second order affects the results in that region, tellurium was used for the filtration, because this element has a resonance in the range of neutrons with energy 4E [pt

  7. Reflective Practices for Teacher Education

    Directory of Open Access Journals (Sweden)

    Paulus Kuswandono

    2017-01-01

    Full Text Available Studies on reflective practice in teacher education are increasingly getting more attention at least in the last 2 decades. This article discusses concepts of reflection and how it is implemented in educating pre-service teachers on their early stage of professional learning. The purposes of doing the reflection for pre-service teachers are not only for illuminating their professional learning experiences, but also to critically reflect their vocation as teachers, including the values which may be dictated to them through rigid regulations. Reflection in teacher education is crucial as it connects well with learning in that learners use reflection to exercise their mind and to evaluate their learning experiences. Besides, this article also highlights some perceived difficulties to implement reflective practice, as well as ways how to promote reflection.   DOI: https://doi.org/10.24071/llt.2012.150102

  8. Guided and Unguided Student Reflections

    OpenAIRE

    Matheson, Amanda; Wood, Laura; Franklin, Scott V.

    2017-01-01

    Self-reflection is important metacognitive skill, enabling students to build coherence into their learning and embed content in a broader context. While various pedagogical techniques exist to encourage student reflection, little research has examined the differences between formally guided, partially guided and unguided reflections. This study focuses on student responses to online Guided Reflection Forms (GRFs) from students in a first-semester non-physics class and, separately, a sophomore...

  9. Students’ Learning through Reflective Journaling

    OpenAIRE

    Alvyda Liuolienė; Regina Metiūnienė

    2011-01-01

    The aim of the article is to get acquainted with the types of journals used in education to help students to learn. The paper presents some ways of fostering student’s learning through reflective journaling. It also describes the key aspects of a new method ARRIVE cycle in connection with teachers preparation to use reflective journals in a classroom. The article also presents self-assessment in reflective journaling and students’ need to self-evaluate their learning process. Reflective journ...

  10. On the radiation accompanying volume reflection

    International Nuclear Information System (INIS)

    Bandiera, L.; Bagli, E.; Berra, A.; Bolognini, D.; Dalpiaz, P.; Della Mea, G.; De Salvador, D.; Guidi, V.; Hasan, S.; Lietti, D.; Mazzolari, A.

    2013-01-01

    The electromagnetic radiation emitted by 120 GeV/c volume-reflected electrons in a bent silicon crystal has been investigated at CERN SPS-H4 beamline. The trajectories of electrons crossing a silicon strip-like crystal have been reconstructed through a telescope system based on high precision micro-strip detectors. The experimental setup was also equipped with a spectrometer and an electromagnetic calorimeter to measure the energy loss of the particles under volume reflection condition. Such a system enabled to record the full photon spectrum up to the nominal energy of the beam. Experimental results were compared to recently developed theoretical approaches based on the quasi-classical operators method of Baier and Katkov

  11. Suppression of Specular Reflections by Metasurface with Engineered Nonuniform Distribution of Reflection Phase

    Directory of Open Access Journals (Sweden)

    Xin Mi Yang

    2015-01-01

    Full Text Available We make preliminary investigations on a new approach to reducing radar cross section (RCS of conducting objects. This approach employs novel planar metasurfaces characterizing nonuniform distribution of reflection phase. The operation principle of this approach and the design rule of the associated metasurfaces are explained using a simplified theoretical model. We then present a design example of such metasurfaces, in which three-layer stacked square patches with variable sizes are utilized as the reflecting elements. The proposed RCS-reduction approach is verified by both numerical simulations and measurements on the example, under the assumption of normal plane wave incidence. It is observed that, in a fairly wide frequency band (from 3.6 to 5.5 GHz, the presented example is capable of suppressing the specular reflections of conducting plates significantly (by more than 7 dB for two orthogonal incident polarizations.

  12. Reflection in Russian Educational Psychology.

    Science.gov (United States)

    Nelissen, Jo M. C.; Tomic, Welko

    This paper discusses the cultural-historical school founded by Vygotsky, Luria, and Leontiev as the theoretical background of Russian educational psychologists who have been studying how children learn to reflect. Two approaches to reflection are examined within the cultural-historical tradition: first, reflection--like other higher psychological…

  13. Reflective Practice: Origins and Interpretations

    Science.gov (United States)

    Reynolds, Michael

    2011-01-01

    The idea of reflection is central to the theory and practice of learning--especially learning which is grounded in past or current experience. This paper proposes a working definition of reflection and reviews its origins and recent developments. The author also provides an account of "critical reflection", including its rationale and…

  14. Teachers’ way of reflecting

    DEFF Research Database (Denmark)

    Lund, Lea

    2016-01-01

    This paper contributes to insights on teachers’ thinking and practice by building partly on the large amount of prior research in the field of continuing professional development (in line with ISATT), and partly on examples from an empirical small-scale study executed in Denmark. The purpose of t......’ reflections on practice. Based on this model, the paper provides a proposal regarding how to work with teachers’ professional development and learning processes. Educational implications and future research directions are discussed.......This paper contributes to insights on teachers’ thinking and practice by building partly on the large amount of prior research in the field of continuing professional development (in line with ISATT), and partly on examples from an empirical small-scale study executed in Denmark. The purpose...... of the Danish study was to investigate and understand teachers’ classroom experiences using Fenstermacher’s approach to develop a practical argument, as these classroom experiences are regarded as a potential source of learning for teachers. A three-level scale model from the study describes the teach-ers...

  15. Cross plane scattering correction

    International Nuclear Information System (INIS)

    Shao, L.; Karp, J.S.

    1990-01-01

    Most previous scattering correction techniques for PET are based on assumptions made for a single transaxial plane and are independent of axial variations. These techniques will incorrectly estimate the scattering fraction for volumetric PET imaging systems since they do not take the cross-plane scattering into account. In this paper, the authors propose a new point source scattering deconvolution method (2-D). The cross-plane scattering is incorporated into the algorithm by modeling a scattering point source function. In the model, the scattering dependence both on axial and transaxial directions is reflected in the exponential fitting parameters and these parameters are directly estimated from a limited number of measured point response functions. The authors' results comparing the standard in-plane point source deconvolution to the authors' cross-plane source deconvolution show that for a small source, the former technique overestimates the scatter fraction in the plane of the source and underestimate the scatter fraction in adjacent planes. In addition, the authors also propose a simple approximation technique for deconvolution

  16. Effect of reflective practice education on self-reflection, insight, and reflective thinking among experienced nurses: a pilot study.

    Science.gov (United States)

    Asselin, Marilyn E; Fain, James A

    2013-01-01

    A mixed-method study was conducted to determine whether nurses' participation in a reflective practice continuing education program using a structured reflection model makes a difference in nurses' self-reflection, insight, and reflective thinking about clinical practice situations. Findings suggested that use of structured reflection using question cues, written narratives, and peer-facilitated reflection increased nurses' engagement in self-reflection and enhanced reflective thinking in practice. Including reflective practice education in novice orientation and preceptor training may be beneficial.

  17. Demystifying the reflective clinical journal

    International Nuclear Information System (INIS)

    Milinkovic, Danielle; Field, Nikki

    2005-01-01

    Student learning on clinical placement is a complex issue and cannot be defined solely by just doing things. Reflection during clinical practice is essential if the student is going to learn from the experience. Therefore it is important for educators to include as part of clinical education programs learning strategies that encourage reflection. The reflective clinical journal is an educational tool that is employed by the School of Medical Radiation Sciences at the University of Sydney to encourage reflection of undergraduate radiation therapy students whilst on clinical placement. This discussion paper explores the key concepts of reflection and the reflective clinical journal. Due to the paucity of information about this issue in radiation therapy the literature reviewed is from across all areas of the health sciences

  18. Berlin Reflectance Spectral Library (BRSL)

    Science.gov (United States)

    Henckel, D.; Arnold, G.; Kappel, D.; Moroz, L. V.; Markus, K.

    2017-09-01

    The Berlin Reflectance Spectral Library (BRSL) provides a collection of reflectance spectra between 0.3 and 17 µm. It was originally dedicated to support space missions to small solar system bodies. Meanwhile the library includes selections of biconical reflectance spectra for spectral data analysis of other planetary bodies as well. The library provides reference spectra of well-characterized terrestrial analogue materials and meteorites for interpretation of remote sensing reflectance spectra of planetary surfaces. We introduce the BRSL, summarize the data available, and access to use them for further relevant applications.

  19. Students’ Learning through Reflective Journaling

    Directory of Open Access Journals (Sweden)

    Alvyda Liuolienė

    2011-04-01

    Full Text Available The aim of the article is to get acquainted with the types of journals used in education to help students to learn. The paper presents some ways of fostering student’s learning through reflective journaling. It also describes the key aspects of a new method ARRIVE cycle in connection with teachers preparation to use reflective journals in a classroom. The article also presents self-assessment in reflective journaling and students’ need to self-evaluate their learning process. Reflective journaling as central to students’ self-evaluation is described as a means of fostering metacognition.

  20. Studies of the Reflection, Refraction and Internal Reflection of Light

    Science.gov (United States)

    Lanchester, P. C.

    2014-01-01

    An inexpensive apparatus and associated experiments are described for studying the basic laws of reflection and refraction of light at an air-glass interface, and multiple internal reflections within a glass block. In order to motivate students and encourage their active participation, a novel technique is described for determining the refractive…

  1. Cultivating Reflective Practitioners in Technology Preparation: Constructing TPACK through Reflection

    Directory of Open Access Journals (Sweden)

    Liangyue Lu

    2013-12-01

    Full Text Available Teaching is a complex profession, which is further complicated by the integration of technology into classrooms. Reflection can help teachers unpack the complexity in their practice. Reflection can be an effective instructional strategy in helping preservice teachers develop technological pedagogical content knowledge (TPACK, the complex and dynamic knowledge necessary for effective technology integration into instruction. In this study, reflective activities were integrated into a Learning By Design (LBD environment, which was created to help preservice teachers develop TPACK. This paper investigated the participants’ TPACK development and examined how reflection helped them construct TPACK. Through content analysis of the participants’ reflective journals, the researcher found that the preservice teachers developed initial TPACK awareness. However, their reflection in technology knowledge and the content aspects of TPACK were limited and superficial. Interviews with the participants showed reflection helped the preservice teachers remember what they learned by describing and elaborating on their in-class experiences, pushed them to think about how to apply what they learned in their future classrooms, and helped them become more reflective and open-minded about using technology in classrooms. Finally, the researcher discussed this study’s implications for teacher educators and researchers.

  2. Reflection and Reflective Practice Discourses in Coaching: A Critical Analysis

    Science.gov (United States)

    Cushion, Christopher J.

    2018-01-01

    Reflection and reflective practice is seen as an established part of coaching and coach education practice. It has become a "taken-for-granted" part of coaching that is accepted enthusiastically and unquestioningly, and is assumed to be "good" for coaching and coaches. Drawing on sociological concepts, a primarily Foucauldian…

  3. Postgraduate Education to Support Organisation Change: A Reflection on Reflection

    Science.gov (United States)

    Stewart, Jim; Keegan, Anne; Stevens, Pam

    2008-01-01

    Purpose: This paper aims to explore how teaching and assessing reflective learning skills can support postgraduate practitioners studying organisational change and explores the challenges for tutors in assessing these journals. Design/methodology/approach: Assessment criteria were developed from the literature on reflective practice and…

  4. Continuous wave terahertz reflection imaging of human colorectal tissue

    Science.gov (United States)

    Doradla, Pallavi; Alavi, Karim; Joseph, Cecil S.; Giles, Robert H.

    2013-03-01

    Continuous wave terahertz (THz) imaging has the potential to offer a safe, non-ionizing, and nondestructive medical imaging modality for delineating colorectal cancer. Fresh excisions of normal colon tissue were obtained from surgeries performed at the University of Massachusetts Medical School, Worcester. Reflection measurements of thick sections of colorectal tissues, mounted in an aluminum sample holder, were obtained for both fresh and formalin fixed tissues. The two-dimensional reflection images were acquired by using an optically pumped far-infrared molecular gas laser operating at 584 GHz with liquid Helium cooled silicon bolometer detector. Using polarizers in the experiment both co-polarized and cross-polarized remittance form the samples was collected. Analysis of the images showed the importance of understanding the effects of formalin fixation while determining reflectance level of tissue response. The resulting co- and cross-polarized images of both normal and formalin fixed tissues showed uniform terahertz response over the entire sample area. Initial measurements indicated a co-polarized reflectance of 16%, and a cross-polarized reflectance of 0.55% from fresh excisions of normal colonic tissues.

  5. Ubuntu feminism: Tentative reflections

    Directory of Open Access Journals (Sweden)

    Drucilla Cornell

    2015-06-01

    Full Text Available The starting-point for the article is to provide a brief background on the Ubuntu Project that Prof. Drucilla Cornell convened in 2003; most notably the interviews conducted in Khayamandi, the support of a sewing collective, and the continued search to launch an Ubuntu Women�s Centre. The article will reflect on some of the philosophical underpinnings of ubuntu, whereafter debates in Western feminism will be revisited. Ubuntu feminism is suggested as a possible response to these types of feminisms. The authors support an understanding of ubuntu as critique and ubuntu feminism accordingly as a critical intervention that recalls a politics of refusal. The article ends by raising the importance of thinking about spatiality through ubuntu, and vice versa. It may seem strange to title an article Ubuntu feminism when feminism itself has often been identified as a European or Western idea. But, this article will argue that ubuntu offers conceptions of transindividuality and ways of social belonging that could respond in a meaningful way to some of European feminism�s own dilemmas and contradictions. Famously, one of the most intense debates in feminism was between those who defended an ethic of care in a relational view of the self, on one side, and those feminists who held on to more traditional conceptions of justice, placing an emphasis on individuality and autonomy, on the other side. The authors will suggest that ubuntu could address this tension in feminism. Thus, in this article the focus will not simply be on ubuntu, in order to recognise that there are other intellectual heritages worthy of consideration, other than those in Europe and the United States. It will also take a next step in arguing that ubuntu may be a better standpoint entirely from which to continue thinking about what it means to be a human being, as well as how to conceive of the integral interconnection human beings all have with one another. This connection through

  6. Water Detection Based on Object Reflections

    Science.gov (United States)

    Rankin, Arturo L.; Matthies, Larry H.

    2012-01-01

    Water bodies are challenging terrain hazards for terrestrial unmanned ground vehicles (UGVs) for several reasons. Traversing through deep water bodies could cause costly damage to the electronics of UGVs. Additionally, a UGV that is either broken down due to water damage or becomes stuck in a water body during an autonomous operation will require rescue, potentially drawing critical resources away from the primary operation and increasing the operation cost. Thus, robust water detection is a critical perception requirement for UGV autonomous navigation. One of the properties useful for detecting still water bodies is that their surface acts as a horizontal mirror at high incidence angles. Still water bodies in wide-open areas can be detected by geometrically locating the exact pixels in the sky that are reflecting on candidate water pixels on the ground, predicting if ground pixels are water based on color similarity to the sky and local terrain features. But in cluttered areas where reflections of objects in the background dominate the appearance of the surface of still water bodies, detection based on sky reflections is of marginal value. Specifically, this software attempts to solve the problem of detecting still water bodies on cross-country terrain in cluttered areas at low cost.

  7. Ethical Reflections on Becoming Teachers

    Science.gov (United States)

    Joseph, Pamela Bolotin

    2016-01-01

    This study analyzes narratives written in a culminating graduate seminar on reflective practice by 36 new secondary teachers who were asked to consider their moral beliefs, moral values and system of ethics as they reflected on their recent student teaching experiences. The findings explore how the participants depicted their constructed moral…

  8. Flexible Bistable Cholesteric Reflective Displays

    Science.gov (United States)

    Yang, Deng-Ke

    2006-03-01

    Cholesteric liquid crystals (ChLCs) exhibit two stable states at zero field condition-the reflecting planar state and the nonreflecting focal conic state. ChLCs are an excellent candidate for inexpensive and rugged electronic books and papers. This paper will review the display cell structure,materials and drive schemes for flexible bistable cholesteric (Ch) reflective displays.

  9. Reflection measurements for luminescent powders

    Science.gov (United States)

    Kroon, R. E.

    2018-04-01

    Luminescent materials are useful in applications varying from lighting and display technologies to document security features and medical research, amongst many others. Measurement of the excitation range is an important consideration, and absorption bands are often determined from a decrease in the measured diffuse reflectance of the material using a ultraviolet-visible (UV-vis) spectrophotometer with an integrating sphere. Such a system may provide questionable results when used to measure the reflectance of a luminescence material, which is demonstrated for a Tb doped silica phosphor, because the system cannot differentiate between the reflected light and luminescence. It is shown that more reliable results are achieved for this phosphor by measuring the reflectance using a synchronous zero-offset scan in a fluorescence spectrometer equipped with an integrating sphere. This method is therefore recommended instead of traditional reflectance measurements using a UV-vis spectrophotometer for luminescent powders.

  10. Centroid crossing

    International Nuclear Information System (INIS)

    Swift, G.

    1990-01-01

    This paper presents an algorithm for finding peaks in data spectra. It is based on calculating a moving centroid across the spectrum and picking off the points between which the calculated centroid crosses the channel number. Interpolation can then yield a more precise peak location. This algorithm can be implemented very efficiently requiring about one addition, subtraction, multiplication, and division operation per data point. With integer data and a centroid window equal to a power of two (so that the division can be done with shifts), the algorithm is particularly suited to efficient machine language implementation. With suitable adjustments (involving only little overhead except at suspected peaks), it is possible to minimize either false peak location or missing good peaks. Extending the method to more dimensions is straightforward although interpolating is more difficult. The algorithm has been used on a variety of nuclear data spectra with great success

  11. Influence of fluctuating strain on exciton reflection spectra

    DEFF Research Database (Denmark)

    Skettrup, Torben

    1982-01-01

    The influence of an internal distribution of strain on the exciton reflection spectra is investigated. The resulting fluctuating optical constants give rise to a fluctuating phase of reflectivity. The standard deviation σ of these phase fluctuations is the quantity which can be observed...... to derive the dependence of the phase of reflectivity on the direction of the fluctuating optical axis. The results obtained for σ are compared with the experimental depolarization spectra of ZnO. The only fitting parameter is the common standard deviation of the strain components. It is found......, for example, between crossed polarizers or from ellipsometric measurements. Assuming the phase fluctuations to obey a Gaussian distribution, σ can be expressed in a simple way in terms of the degree of polarization or the depolarization of the reflected light. σ is then derived in terms of the standard...

  12. Plasma density fluctuation measurements from coherent and incoherent microwave reflection

    International Nuclear Information System (INIS)

    Conway, G.D.; Schott, L.; Hirose, A.

    1996-01-01

    Using the spatial coherency present in a reflected microwave signal (Conway et al 1994 Rev. Sci. Instrum. 65 2920) it is possible to measure a coherent, Γ c , and an incoherent, Γ i , reflection coefficient (proportional to the radar cross section) from a turbulent plasma cutoff layer. Results acquired with a 17 GHz reflectometer from a STOR-M tokamak edge region (r/a ∼ 0.8) give significant Γ c and Γ i , which suggests two-dimensional structure in the reflection layer. Using a 'distorted-mirror' model for the plasma fluctuations, estimates of an effective radial width, σ, and poloidal correlation length, L p , can be derived from the reflection coefficients. STOR-M results typically give a σ of a few millimetres and an L p of a couple of centimetres. (author)

  13. Reflection measurements of microwave absorbers

    Science.gov (United States)

    Baker, Dirk E.; van der Neut, Cornelis A.

    1988-12-01

    A swept-frequency interferometer is described for making rapid, real-time assessments of localized inhomogeneities in planar microwave absorber panels. An aperture-matched exponential horn is used to reduce residual reflections in the system to about -37 dB. This residual reflection is adequate for making comparative measurements on planar absorber panels whose reflectivities usually fall in the -15 to -25 dB range. Reflectivity measurements on a variety of planar absorber panels show that multilayer Jaumann absorbers have the greatest inhomogeneity, while honeycomb absorbers generally have excellent homogeneity within a sheet and from sheet to sheet. The test setup is also used to measure the center frequencies of resonant absorbers. With directional couplers and aperture-matched exponential horns, the technique can be easily applied in the standard 2 to 40 GHz waveguide bands.

  14. Ibuanyidanda (Complementary Reflection), Communalism and ...

    African Journals Online (AJOL)

    Fr. Prof. Asouzu

    Glossary of Igbo Terms and Phrases ihe ahụ na anya ... other words, it is in mutual dependence that the feeling of intimacy found among kindred ..... Complementary Reflection, Communalism and Theory Formulation in African Philosophy 25.

  15. Worldwide Marine Seismic Reflection Profiles

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC maintains a large volume of both Analog and Digital seismic reflection data. Currently only a limited number of lines are available online. Digital data include...

  16. Reflective Methodology: The Beginning Teacher

    Science.gov (United States)

    Templeton, Ronald K.; Siefert, Thomas E.

    1970-01-01

    Offers a variety of specific techniques which will help the beginning teacher to implement reflective methodology and create an inquiry-centered classroom atmosphere, at the same time meeting the many more pressing demands of first-year teaching. (JES)

  17. High-resolution reflection spectroscopy

    International Nuclear Information System (INIS)

    Ducloy, Martial

    1997-01-01

    In this article some recent developments in selective reflection spectroscopy is reviewed and the various ways to extend Doppler free techniques to this spectroscopic field is discussed. Its main feature is to probe atomic gas close to the cell boundaries

  18. Analytic Reflected Lightcurves for Exoplanets

    Science.gov (United States)

    Haggard, Hal M.; Cowan, Nicolas B.

    2018-04-01

    The disk-integrated reflected brightness of an exoplanet changes as a function of time due to orbital and rotational motion coupled with an inhomogeneous albedo map. We have previously derived analytic reflected lightcurves for spherical harmonic albedo maps in the special case of a synchronously-rotating planet on an edge-on orbit (Cowan, Fuentes & Haggard 2013). In this letter, we present analytic reflected lightcurves for the general case of a planet on an inclined orbit, with arbitrary spin period and non-zero obliquity. We do so for two different albedo basis maps: bright points (δ-maps), and spherical harmonics (Y_l^m-maps). In particular, we use Wigner D-matrices to express an harmonic lightcurve for an arbitrary viewing geometry as a non-linear combination of harmonic lightcurves for the simpler edge-on, synchronously rotating geometry. These solutions will enable future exploration of the degeneracies and information content of reflected lightcurves, as well as fast calculation of lightcurves for mapping exoplanets based on time-resolved photometry. To these ends we make available Exoplanet Analytic Reflected Lightcurves (EARL), a simple open-source code that allows rapid computation of reflected lightcurves.

  19. Nonlocal superconducting correlations in graphene in the quantum Hall regime

    Science.gov (United States)

    Beconcini, Michael; Polini, Marco; Taddei, Fabio

    2018-05-01

    We study Andreev processes and nonlocal transport in a three-terminal graphene-superconductor hybrid system under a quantizing perpendicular magnetic field [G.-H. Lee et al., Nat. Phys. 13, 693 (2017), 10.1038/nphys4084]. We find that the amplitude of the crossed Andreev reflection (CAR) processes crucially depends on the orientation of the lattice. By employing Landauer-Büttiker scattering theory, we find that CAR is generally very small for a zigzag edge, while for an armchair edge it can be larger than the normal transmission, thereby resulting in a negative nonlocal resistance. In the case of an armchair edge and with a wide superconducting region (as compared to the superconducting coherence length), CAR exhibits large oscillations as a function of the magnetic field due to interference effects. This results in sign changes of the nonlocal resistance.

  20. Reflections

    Indian Academy of Sciences (India)

    physics, and to whom he always remained close - his sister Maja. .... moved to Munich at the beginning of 1882, when Albert was barely two years old. ... This was demonstrated during a further change in the sphere of activity of .... As is well known, in Germany one uses the polite form "Sie" for adults and for people who.

  1. Reflections

    Indian Academy of Sciences (India)

    2004-04-01

    Apr 1, 2004 ... journal Current Science, Vol 61, 1991, pp.594-600. It is an ... could be explained as mere imperfections in the fossil record. .... would almost seem that exposure to the rigours of the climate had quickened the pace ... would be interesting to know whether this telescoping effect is the outward manifesta-.

  2. Reflections

    Indian Academy of Sciences (India)

    making computer programs 'human like' by building in learning and ... discussed the problems of control and communication in the living organism and the machine. ... To be effective in warding off disastrous consequences, our understanding.

  3. Reflections

    Indian Academy of Sciences (India)

    not only in linguistics hut also in allied fields, splitting social scientists into t\\VO groups, Chomskyan and others. ... views on language, IlO\\\\"knoVv'Il as 'Standard Theory', generated a ... For the human mind, learning is a kind of reminiscence.

  4. Reflections

    Indian Academy of Sciences (India)

    future seemed secure, and there was such complete harmony of character between ... was at once so taken with the idea that he was able to persuade Hermann Einstein to .... A liberal spirit, undogmatic in matters of religion, brought by both.

  5. Reflections

    Indian Academy of Sciences (India)

    Of what lasting benefit has been man's use of science and of the new instruments which his research .... future moves about the laboratory or the field, every time he looks at something worthy of ... Yet the speed of action, the intricacy of .... physician, puzzled by a patient's reactions, strikes the trail established in studying an.

  6. Reflections

    DEFF Research Database (Denmark)

    du Gay, Paul; Vikkelsø, Signe

    2012-01-01

    The notion of ‘change’ has become pervasive in contemporary organizational discourse. On the one hand, change is represented as an organizational imperative that increasingly appears to trump all other concerns. On the other hand, change is addressed as an abstract, generic entity that can be the...

  7. Reflections

    Indian Academy of Sciences (India)

    Newton that there was a transition to the understanding and explanation of natural .... All of this again is accessible to human understanding, and new laws of nature couched in ..... able limits to communication with other individuals.

  8. Reflections

    Indian Academy of Sciences (India)

    The modem picture of the basic constituents and their interactions is described by the so called ... According to him, however great the ... Finally, it is good to remember the words of Bhabha that only science and technology can solve the.

  9. A three-microphone acoustic reflection technique using transmitted acoustic waves in the airway.

    Science.gov (United States)

    Fujimoto, Yuki; Huang, Jyongsu; Fukunaga, Toshiharu; Kato, Ryo; Higashino, Mari; Shinomiya, Shohei; Kitadate, Shoko; Takahara, Yutaka; Yamaya, Atsuyo; Saito, Masatoshi; Kobayashi, Makoto; Kojima, Koji; Oikawa, Taku; Nakagawa, Ken; Tsuchihara, Katsuma; Iguchi, Masaharu; Takahashi, Masakatsu; Mizuno, Shiro; Osanai, Kazuhiro; Toga, Hirohisa

    2013-10-15

    The acoustic reflection technique noninvasively measures airway cross-sectional area vs. distance functions and uses a wave tube with a constant cross-sectional area to separate incidental and reflected waves introduced into the mouth or nostril. The accuracy of estimated cross-sectional areas gets worse in the deeper distances due to the nature of marching algorithms, i.e., errors of the estimated areas in the closer distances accumulate to those in the further distances. Here we present a new technique of acoustic reflection from measuring transmitted acoustic waves in the airway with three microphones and without employing a wave tube. Using miniaturized microphones mounted on a catheter, we estimated reflection coefficients among the microphones and separated incidental and reflected waves. A model study showed that the estimated cross-sectional area vs. distance function was coincident with the conventional two-microphone method, and it did not change with altered cross-sectional areas at the microphone position, although the estimated cross-sectional areas are relative values to that at the microphone position. The pharyngeal cross-sectional areas including retropalatal and retroglossal regions and the closing site during sleep was visualized in patients with obstructive sleep apnea. The method can be applicable to larger or smaller bronchi to evaluate the airspace and function in these localized airways.

  10. CHALLENGES IN CROSS CULTURAL ADVERTISING

    Directory of Open Access Journals (Sweden)

    Yuni Retnowati

    2016-04-01

    Full Text Available At first, marketing practitioners and academics consider standardized approaches to marketing and advertising strategies in globalization, and then some studies proved that the standardization of advertising across culture is not valid. Therefore, cross cultural advertising takes local culture into account when conveying messages in advertisements. Cross cultural understanding is very important in order to produce successful localized advertising that would reflect the cultural values and norms of intended audience. Challenge in cross cultural advertising is the problem of communicating to people of diverse cultural background. Cross cultural solutions are applied in areas such as language, communication style, images and cultural values. Cross cultural advertising is simply about using common sense and analyzing how the different elements of an advertising campaign are impacted by culture and modifying them to best speak to the target audience. Other challenges are determining between standardization and adaptation of cultural values content of advertising when facing different people from diverse cultures. In academic side, the challenge is preparing students to design advertisements that communicate effectively to diverse cultures.

  11. Reflectance spectra of subarctic lichens

    International Nuclear Information System (INIS)

    Petzold, D.E.; Goward, S.N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the mid latitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 μm, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future. (author)

  12. Low reflectance radio frequency load

    Science.gov (United States)

    Ives, R. Lawrence; Mizuhara, Yosuke M

    2014-04-01

    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  13. Reflectance spectra of subarctic lichens

    Science.gov (United States)

    Petzold, Donald E.; Goward, Samuel N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the midlatitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 microns, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future.

  14. Tunneling and reflection in unimolecular reaction kinetic energy release distributions

    Science.gov (United States)

    Hansen, K.

    2018-02-01

    The kinetic energy release distributions in unimolecular reactions is calculated with detailed balance theory, taking into account the tunneling and the reflection coefficient in three different types of transition states; (i) a saddle point corresponding to a standard RRKM-type theory, (ii) an attachment Langevin cross section, and (iii) an absorbing sphere potential at short range, without long range interactions. Corrections are significant in the one dimensional saddle point states. Very light and lightly bound absorbing systems will show measurable effects in decays from the absorbing sphere, whereas the Langevin cross section is essentially unchanged.

  15. Audible reflection density for different late reflection criteria in rooms

    DEFF Research Database (Denmark)

    Krueger, Donata; Jeong, Cheol-Ho; Brunskog, Jonas

    2012-01-01

    For reasonably accurate but practical auralizations, some simplifications and approximations are needed. The main issue in the present investigation is that the reflection density of a room impulse response, in theory, increases so fast as a quadratic function of the elapsed time, even assuming...

  16. Assessing Reflection: Understanding Skill Development through Reflective Learning Journals

    Science.gov (United States)

    Cathro, Virginia; O'Kane, Paula; Gilbertson, Deb

    2017-01-01

    Purpose: The purpose of this paper is to suggest ways in which business educators can interact successfully with reflective learning journals (RLJs). Specifically, the research was interested in how students used RLJs and how educators assessed these RLJs. Design/methodology/approach: In total, 31 RLJs, submitted as part of an international…

  17. Reflective Drawing as a Tool for Reflection in Design Research

    Science.gov (United States)

    Calvo, Mirian

    2017-01-01

    This article explores the role of drawing as a tool for reflection. It reports on a PhD research project that aims to identify and analyse the value that co-design processes can bring to participants and their communities. The research is associated with Leapfrog, a three-year project funded by the UK Arts and Humanities Research Council (AHRC).…

  18. Methodological Reflections: Inter- ethnic Research

    DEFF Research Database (Denmark)

    Singla, Rashmi

    2010-01-01

    with both youth and the parental generation with ethnic minority background in Denmark. These reflections include implications and challenges related to researcher’s national, ethnic background and educational, professional position in encounter with   diverse ‘researched persons’ such as youth......This article reflects on the methodological and epistemological aspects of the ethical issues involved in encounters between researcher and research participants with ethnic minority background in contexts with diversity. Specific challenges involved in longitudinal research (10 - 15 years......) are also considered. The issues related to the social relevance of the research deriving from psycho political validity implying consideration of power dynamics in the personal, relational and collective domains are included. The primary basis for these reflections is a follow-up study concerning young...

  19. Reflecting variable opening insulating panel

    International Nuclear Information System (INIS)

    Nungesser, W.T.

    1976-01-01

    A description is given of a reflecting variable opening insulating panel assembly, comprising a static panel assembly of reflecting insulation sheets forming a cavity along one side of the panel and a movable panel opening out by sliding from the cavity of the static panel, and a locking device for holding the movable panel in a position extending from the cavity of the static panel. This can apply to a nuclear reactor of which the base might require maintenance and periodical checking and for which it is desirable to have available certain processes for the partial dismantling of the insulation [fr

  20. Guide on reflectivity data analysis

    International Nuclear Information System (INIS)

    Lee, Jeong Soo; Ku, Ja Seung; Seong, Baek Seok; Lee, Chang Hee; Hong, Kwang Pyo; Choi, Byung Hoon

    2004-09-01

    This report contains reduction and fitting process of neutron reflectivity data by REFLRED and REFLFIT in NIST. Because the detail of data reduction like BKG, footprint and data normalization was described, it will be useful to the user who has no experience in this field. Also, reflectivity and BKG of d-PS thin film were measured by HANARO neutron reflectometer. From these, the structure of d-PS thin film was analyzed with REFLRED and REFLFIT. Because the structure of thin film such as thickness, roughness and SLD was attained in the work, the possibility of data analysis with REFLRED and REFLFIT was certified

  1. Fragments on teachers' reflective practicum

    Directory of Open Access Journals (Sweden)

    Živković Predrag Ž.

    2013-01-01

    Full Text Available in many historical and comparative overviews of the works, in which there is an analytical discussion of the dominant pedagogical theories in the twentieth century, John Dewey (Dewey, 1933 is referred to as the founder and creator of the concept of reflection (reflective thought and knowledge in practice. Reflection as a concept is understood as the forms and the form of problem solving, as well as continuously thinking about the causes of problems in situations in situ, including active and systematically and consistently changing connecting ideas with solutions to the problems and situations that preceded them (Hatton & Smith, 1995. Reflective thinking is the most general level to tackle practical problems, allowing the ''recommended'' doubts and confusion before proposing possible solutions to the problem. Dewey wrote about a reflective action which refers to the use of solutions to the problem and to thinking through the course of the action. in later works of the authors who have dealt with this problem, an unambiguous link can be observed between the so-called ''professional'' action and the reflection on action which, in this cyclical relationship, leads to visible changes (Zeichner & Gore, 1984. Already at first glance, this implies a connection with experiential learning and adult position of observation and reflection in various models of experiential learning, which will be discussed later. it would be useful to compare this method with a cyclic action of routine as an expression of impulse, tradition and authority. Reflective action, as opposed to the routine, is a consistently and carefully thought-out action (practice reflection, which is an ''awakened'' knowledge and belief, and that is an expression of openness, accountability and commitment. We are ready for reflection, says Schon, when the ''knowledge-in-action'' - a kind of knowledge that professionals notice when it is acted spontaneously - occurs suddenly and unintentionally

  2. Border Crossing/Entry Data - Boarder Crossing

    Data.gov (United States)

    Department of Transportation — Border Crossing/Entry Data provides summary statistics for incoming crossings at the U.S.-Canadian and the U.S.-Mexican border at the port level. Data are available...

  3. Creative reflection in industrial design

    NARCIS (Netherlands)

    Verbrugge, J.K.; Verbrugge, J.K.

    2012-01-01

    The dissertation is a reflection of the writer on his career as an industrial designer of Demand-Driven Design for a period of approximately 25 years. This period is exposed with a discussion of five designs. The projects are introduced by developments in the surrounding design landscape, such as

  4. Reflections on Ethics in Practice

    Science.gov (United States)

    Adams, Helen R.

    2009-01-01

    Each profession has its own code of ethics. The Merriam-Webster Online Dictionary (2008) defines professional ethics as "the principles of conduct governing an individual or a group." The Code of Ethics of the American Library Association (ALA Council 2008) has served librarians for seventy years and reflects the ideals toward which all librarians…

  5. Questioning Intuition through Reflective Engagement

    Science.gov (United States)

    Schmidt, Christopher D.

    2014-01-01

    Current literature on ethics and moral development focuses on discussion concerning the impact of intuition on moral decision-making. Through the use of student journal reflections over the course of one semester, this study utilized a grounded theory approach in order to explore and understand participant levels of awareness and understanding of…

  6. The Hiroshima Experience: Two Reflections.

    Science.gov (United States)

    Enloe, Walter; Cogan, John

    1985-01-01

    The bombing of Hiroshima changed forever the concept of conflict and warfare in the human family. Two Americans, one having grown up in Hiroshima and the other having spent one year in the city as a Fullbright research scholar, reflect on the Hiroshima experience. (RM)

  7. Five Perspectives on Reflective Journaling

    Science.gov (United States)

    Boden, Carrie J.; Cook, Deborah; Lasker-Scott, Tennille; Moore, Sylvia; Shelton, Debbie

    2006-01-01

    It has long been posited in the field of adult education and elsewhere that reflection is an integral part of one's teaching practice and as well as a beneficial learning tool for students. It was with this orientation to practice that Dr. Carrie J. Boden started her first year of teaching in the Adult Education Masters Degree Program at the…

  8. Simulating complex noise barrier reflections

    NARCIS (Netherlands)

    Eerden, F.J.M. van der; Lutgendorf, D.; Roo, F. de

    2011-01-01

    Within the EU FP7 QUIESST project, QUIeting the Environment for a Sustainable Surface Transport, a test method is being developed for the reflectivity of noise barriers. The method needs to account for a complex shape of barriers and the use of various types of absorbing materials. The performance

  9. Vegetables, Coctails & Reflections / Marco Laimre

    Index Scriptorium Estoniae

    Laimre, Marko, 1968-

    2006-01-01

    Pealkirja "Vegetables, Coctails & Reflections" kandis Tallinna Kunstihoones 8.04.-28.05.2006 avatud Elin Kardi, Marko Mäetamme, Marco Laimre ja Andres Tali ühisnäitusel "Vägivald ja propaganda" Marco Laimre installatsioon. Marco Laimre esinemine raadiosaates "kunst.er" Klassikaraadios 16.04.2006

  10. REFLECTION AND REFRACTION, VOLUME 2.

    Science.gov (United States)

    KLAUS, DAVID J.; AND OTHERS

    THIS VOLUME 2 OF A TWO-VOLUME SET PROVIDES AUTOINSTRUCTION IN PHYSICS. THE UNITS COVERED IN THIS VOLUME ARE (1) REFLECTION OF LIGHT, (2) PHOTOMETRY, (3) POLARIZATION, (4) REFRACTION OF LIGHT, (5) SNELL'S LAW, (6) LENSES, FOCUS, AND FOCAL POINTS, (7) IMAGE FORMATION, AND (8) ABERRATIONS, THE EYE, AND MAGNIFICATION. THE INTRODUCTION AND UNITS ON…

  11. Reflections on a Disco Ball

    Science.gov (United States)

    Ribeiro, Jair Lúcio Prados

    2016-01-01

    A disco ball is a spherical object covered with small plane mirrors. When light reflects on these mirrors, it is scattered in many directions, producing a novel effect. The mirror globe is usually set to rotate, creating a profusion of moving spots (Fig. 1). In this article, we present a geometrical description of the movement of these spots and…

  12. REFLECTION IN RUSSIAN EDUCATIONAL PSYCHOLOGY

    NARCIS (Netherlands)

    Nelissen, J.M.C.; Tomic, W.

    2008-01-01

    The present article explores the theoretical underpinnings upon which Russian psychologists base their analysis of reflection. The intention is to arrive at a clearer understanding of their research aims and research methods, and to explore the relevance of their research to educational practice.

  13. Gamma camera with reflectivity mask

    International Nuclear Information System (INIS)

    Stout, K.J.

    1980-01-01

    In accordance with the present invention there is provided a radiographic camera comprising: a scintillator; a plurality of photodectors positioned to face said scintillator; a plurality of masked regions formed upon a face of said scintillator opposite said photdetectors and positioned coaxially with respective ones of said photodetectors for decreasing the amount of internal reflection of optical photons generated within said scintillator. (auth)

  14. Studies on the detection of concealed objects using the neutron reflection method

    International Nuclear Information System (INIS)

    Papp, A.

    2013-01-01

    The increment of reflected thermal and 1.45 eV resonance neutrons vs. the thickness of the reflector has been measured and described by an analytical expression. Macroscopic, Σ β , and microscopic, σ β , reflection cross sections averaged over the bulk reflector substances were deduced for some elements and compounds. It was found that the σ β values are additive even for bulk samples and so the σ βmol could be given for some illicit drugs, explosives and hiding materials. - Highlights: ► The effect of reflector materials on the increment of neutrons were determined. ► Macroscopic and microscopic reflection cross sections averaged over bulk samples were determined. ► Simple analytical expression was given to describe the yield of reflected neutrons. ► The observed additive behavior in reflected neutrons rendered to characterize other materials

  15. Reflection group on 'Expert Culture'

    International Nuclear Information System (INIS)

    Eggermont, G.

    2000-01-01

    As part of SCK-CEN's social sciences and humanities programme, a reflection group on 'Expert Culture' was established. The objectives of the reflection group are: (1) to clarify the role of SCK-CEN experts; (2) to clarify the new role of expertise in the evolving context of risk society; (3) to confront external views and internal SCK-CEN experiences on expert culture; (4) to improve trust building of experts and credibility of SCK-CEN as a nuclear actor in society; (5) to develop a draft for a deontological code; (6) to integrate the approach in training on assertivity and communication; (7) to create an output for a topical day on the subject of expert culture. The programme, achievements and perspectives of the refection group are summarised

  16. Introductory essay: new horizons in cross cultural management

    NARCIS (Netherlands)

    Zhu, Y.; Ulijn, J.M.

    2005-01-01

    In this special issue, we present a research forum on current issues in cross cultural management in New Zealand, Australia and the Asian-Pacific Region. Our theme is new horizons in cross cultural management, which is reflected in both topic and approach. Our topics are related to the Asia Pacific

  17. AntiReflection Coating D

    International Nuclear Information System (INIS)

    AIKEN, DANIEL J.

    1999-01-01

    Analytical expressions used to optimize AR coatings for single junction solar cells are extended for use in monolithic, series interconnected multi-junction solar cell AR coating design. The result is an analytical expression which relates the solar cell performance (through J(sub sc)) directly to the AR coating design through the device reflectance. It is also illustrated how AR coating design be used to provide an additional degree of freedom for current matching multi-junction devices

  18. Quantum coherence in the reflection of above barrier wavepackets

    Science.gov (United States)

    Petersen, Jakob; Pollak, Eli

    2018-02-01

    The quantum phenomenon of above barrier reflection is investigated from a time-dependent perspective using Gaussian wavepackets. The transition path time distribution, which in principle is experimentally measurable, is used to study the mean flight times ⟨t⟩R and ⟨t⟩T associated with the reflection and the transmission over the barrier paying special attention to their dependence on the width of the barrier. Both flight times, and their difference Δt, exhibit two distinct regimes depending on the ratio of the spatial width of the incident wavepacket and the length of the barrier. When the ratio is larger than unity, the reflection and transmission dynamics are coherent and dominated by the resonances above the barrier. The flight times ⟨t⟩R/T and the flight time difference Δt oscillate as a function of the barrier width (almost in phase with the transmission probability). These oscillations reflect a momentum filtering effect related to the coherent superposition of the reflected and transmitted waves. For a ratio less than unity, the barrier reflection and transmission dynamics are incoherent and the oscillations are absent. The barrier width which separates the coherent and incoherent regimes is identified analytically. The oscillatory structure of the time difference Δt as a function of the barrier width in the coherent regime is absent when considered in terms of the Wigner phase time delays for reflection and transmission. We conclude that the Wigner phase time does not correctly describe the temporal properties of above barrier reflection. We also find that the structure of the reflected and transmitted wavepackets depends on the coherence of the process. In the coherent regime, the wavepackets can have an overlapping peak structure, but the peaks are not fully resolved. In the incoherent regime, the wavepackets split in time into distinct separated Gaussian like waves, each one reflecting the number of times the wavepacket crosses the barrier

  19. Reflective array modeling for reflective and directional SAW transducers.

    Science.gov (United States)

    Morgan, D P

    1998-01-01

    This paper presents a new approximate method for analyzing reflective SAW transducers, with much of the convenience of the coupled-mode (COM) method but with better accuracy. Transduction accuracy is obtained by incorporating the accurate electrostatic solution, giving for example correct harmonics, and allowance for electrode width variation, in a simple manner. Results are shown for a single-electrode transducer, Natural SPUDT and DART SPUDT, each using theoretically derived parameters. In contrast to the COM, the RAM can give accurate results for short or withdrawal-weighted transducers and for wide analysis bandwidth.

  20. Spatial distribution of reflected gamma rays by Monte Carlo simulation

    International Nuclear Information System (INIS)

    Jehouani, A.; Merzouki, A.; Boutadghart, F.; Ghassoun, J.

    2007-01-01

    In nuclear facilities, the reflection of gamma rays of the walls and metals constitutes an unknown origin of radiation. These reflected gamma rays must be estimated and determined. This study concerns reflected gamma rays on metal slabs. We evaluated the spatial distribution of the reflected gamma rays spectra by using the Monte Carlo method. An appropriate estimator for the double differential albedo is used to determine the energy spectra and the angular distribution of reflected gamma rays by slabs of iron and aluminium. We took into the account the principal interactions of gamma rays with matter: photoelectric, coherent scattering (Rayleigh), incoherent scattering (Compton) and pair creation. The Klein-Nishina differential cross section was used to select direction and energy of scattered photons after each Compton scattering. The obtained spectra show peaks at 0.511 * MeV for higher source energy. The Results are in good agreement with those obtained by the TRIPOLI code [J.C. Nimal et al., TRIPOLI02: Programme de Monte Carlo Polycinsetique a Trois dimensions, CEA Rapport, Commissariat a l'Energie Atomique.

  1. Reflections on researching rape resistance.

    Science.gov (United States)

    Ullman, Sarah E

    2014-03-01

    This article provides a retrospective account of my experience embarking on research about women's resistance to rape, including reflections on personal and professional experiences related to studying this topic. I discuss factors inspiring my interest, including pioneering feminist rape researchers, my experience as a woman living with the reality and fear of rape, and influential mentors who facilitated my career development as a scholar in graduate school and beyond. I weave this narrative together with my thoughts about how the study of resistance relates to other important issues in the field of sexual assault including alcohol, recovery, and prevention.

  2. Hospital management. The reflective practitioner.

    Science.gov (United States)

    Campbell, I

    Ian Campbell's paper, originally delivered at a conference on the development of 'The reflective practitioner' while he was Unit General Manager of Sunderland Royal Infirmary, describes the liaison between general and nurse managers in the hospital. Management must give a hospital organisation direction and must set the parameters of corporate and individual performance, but it must also be responsive to the feedback received from practising clinicians. The key concept is quality of service, and in this managers and practitioners can work together towards a common goal.

  3. Reflections on a digital upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Tadjalli, M.

    2013-07-01

    Upon receiving US NRC's approval in 2010, the first RPS/ESPS digital upgrade using TELEPERM® XS technology was successfully installed in Spring of 2011 at the first Unit of a three-unit station, followed by the 2nd Unit installation in spring of 2012. Both Units' systems have been operating flawlessly since installation. After about two years of operation, a reflection on digital upgrades and lessons learned, from a vendor perspective, provides valuable insight for the commercial nuclear power industry.

  4. Positronium reflection and positronium beams

    International Nuclear Information System (INIS)

    Weber, M.; Tang, S.; Khatri, R.; Roellig, L.O.; Viescas, A.J.; Berko, S.; Canter, K.F.; Lynn, K.G.; Mills, A.P. Jr.

    1989-01-01

    We have observed specular reflection of positronium, Ps, and established that there is adequate intensity at higher energies to make further study worthwhile. The scattering appears to be restricted to the outermost surface with a mean free path of (0.75 ± 0.15)Angstrom for Ps in LiF(100). With a greater intensity Ps beam one should see higher order diffraction beams as the result of the periodicity of the surface. Ps diffraction thus offers the possibility of being a novel and valuable probe to study the outermost surface and to study adsorbents on it. Two methods for producing Ps beams are described. 29 refs., 11 figs

  5. The digital divide: philosophical reflection

    Directory of Open Access Journals (Sweden)

    Dedyulina Marina Anatolevna

    2017-07-01

    Full Text Available The problem of digital divide itself is interesting for philosophical reflection as it lies at the crossroads of interests of social and political philosophy, philosophy of technology and epistemology, and these are just some of them. Due to the constant development of information technologies and the introduction of new technologies the digital divide is a dynamic problem. The main aim of this work is to analyse the conceptual and descriptive aspects of the problem of the digital divide, to get a more complete picture of the phenomenon. The digital divide is a complex problem that has social, political, cultural and ethical aspects.

  6. Reflections on Design Methodology Research

    DEFF Research Database (Denmark)

    2011-01-01

    We shall reflect on the results of Design Methodology research and their impact on design practice. In the past 50 years the number of researchers in the field has expanded enormously – as has the number of publications. During the same period design practice and its products have changed...... and produced are also now far more complex and distributed, putting designers under ever increasing pressure. We shall address the question: Are the results of Design Methodology research appropriate and are they delivering the expected results in design practice? In our attempt to answer this question we...

  7. Cosmological Reflection of Particle Symmetry

    Directory of Open Access Journals (Sweden)

    Maxim Khlopov

    2016-08-01

    Full Text Available The standard model involves particle symmetry and the mechanism of its breaking. Modern cosmology is based on inflationary models with baryosynthesis and dark matter/energy, which involves physics beyond the standard model. Studies of the physical basis of modern cosmology combine direct searches for new physics at accelerators with its indirect non-accelerator probes, in which cosmological consequences of particle models play an important role. The cosmological reflection of particle symmetry and the mechanisms of its breaking are the subject of the present review.

  8. Discharge lamp with reflective jacket

    Science.gov (United States)

    MacLennan, Donald A.; Turner, Brian P.; Kipling, Kent

    2001-01-01

    A discharge lamp includes an envelope, a fill which emits light when excited disposed in the envelope, a source of excitation power coupled to the fill to excite the fill and cause the fill to emit light, and a reflector disposed around the envelope and defining an opening, the reflector being configured to reflect some of the light emitted by the fill back into the fill while allowing some light to exit through the opening. The reflector may be made from a material having a similar thermal index of expansion as compared to the envelope and which is closely spaced to the envelope. The envelope material may be quartz and the reflector material may be either silica or alumina. The reflector may be formed as a jacket having a rigid structure which does not adhere to the envelope. The lamp may further include an optical clement spaced from the envelope and configured to reflect an unwanted component of light which exited the envelope back into the envelope through the opening in the reflector. Light which can be beneficially recaptured includes selected wavelength regions, a selected polarization, and selected angular components.

  9. The seismic reflection inverse problem

    International Nuclear Information System (INIS)

    Symes, W W

    2009-01-01

    The seismic reflection method seeks to extract maps of the Earth's sedimentary crust from transient near-surface recording of echoes, stimulated by explosions or other controlled sound sources positioned near the surface. Reasonably accurate models of seismic energy propagation take the form of hyperbolic systems of partial differential equations, in which the coefficients represent the spatial distribution of various mechanical characteristics of rock (density, stiffness, etc). Thus the fundamental problem of reflection seismology is an inverse problem in partial differential equations: to find the coefficients (or at least some of their properties) of a linear hyperbolic system, given the values of a family of solutions in some part of their domains. The exploration geophysics community has developed various methods for estimating the Earth's structure from seismic data and is also well aware of the inverse point of view. This article reviews mathematical developments in this subject over the last 25 years, to show how the mathematics has both illuminated innovations of practitioners and led to new directions in practice. Two themes naturally emerge: the importance of single scattering dominance and compensation for spectral incompleteness by spatial redundancy. (topical review)

  10. Reflection-type hologram for atoms

    International Nuclear Information System (INIS)

    Shimizu, Fujio; Fujita, Jun-ichi

    2002-01-01

    A cold metastable neon atomic beam was manipulated with a reflective amplitude hologram that was encoded on a silicon surface. A black-and-white pattern of atoms was reconstructed on a microchannel plate detector. The hologram used the enhanced quantum reflection developed by authors and was made of a two-dimensional array of rectangular low and high reflective cells. The surface of the high reflective cell was composed of regularly spaced roof-shaped ridges, while the low reflective cell was simply a flat surface. The hologram was the first demonstration of reflective atom-optical elements that used universal interaction between a neutral atom and solid surface

  11. Ultra-wideband reflective polarization converter based on anisotropic metasurface

    Science.gov (United States)

    Wu, Jia-Liang; Lin, Bao-Qin; Da, Xin-Yu

    2016-08-01

    In this paper, we propose an ultra-wideband reflective linear cross-polarization converter based on anisotropic metasurface. Its unit cell is composed of a square-shaped resonator with intersectant diagonal and metallic ground sheet separated by dielectric substrate. Simulated results show that the converter can generate resonances at four frequencies under normal incident electromagnetic (EM) wave, leading to the bandwidth expansion of cross-polarization reflection. For verification, the designed polarization converter is fabricated and measured. The measured and simulated results agree well with each other, showing that the fabricated converter can convert x- or y-polarized incident wave into its cross polarized wave in a frequency range from 7.57 GHz to 20.46 GHz with a relative bandwidth of 91.2%, and the polarization conversion efficiency is greater than 90%. The proposed polarization converter has a simple geometry but an ultra wideband compared with the published designs, and hence possesses potential applications in novel polarization-control devices. Project supported by the National Natural Science Foundation of China (Grant Nos. 61471387, 61271250, and 61571460).

  12. Ultra-wideband reflective polarization converter based on anisotropic metasurface

    International Nuclear Information System (INIS)

    Wu Jia-Liang; Lin Bao-Qin; Da Xin-Yu

    2016-01-01

    In this paper, we propose an ultra-wideband reflective linear cross-polarization converter based on anisotropic metasurface. Its unit cell is composed of a square-shaped resonator with intersectant diagonal and metallic ground sheet separated by dielectric substrate. Simulated results show that the converter can generate resonances at four frequencies under normal incident electromagnetic (EM) wave, leading to the bandwidth expansion of cross-polarization reflection. For verification, the designed polarization converter is fabricated and measured. The measured and simulated results agree well with each other, showing that the fabricated converter can convert x - or y -polarized incident wave into its cross polarized wave in a frequency range from 7.57 GHz to 20.46 GHz with a relative bandwidth of 91.2%, and the polarization conversion efficiency is greater than 90%. The proposed polarization converter has a simple geometry but an ultra wideband compared with the published designs, and hence possesses potential applications in novel polarization-control devices. (paper)

  13. Andreev levels in a single-channel conductor

    DEFF Research Database (Denmark)

    Titov, M.; Mortensen, Asger; Schomerus, H.

    2001-01-01

    We calculate the subgap density of states of a disordered single-channel normal metal connected to a superconductor at one end (normal-metal-superconductor junction) or at both ends [superconductor-normal-metal-superconductor (SNS) junction]. The probability distribution of the energy of a bound ...

  14. Observation of conductance doubling in an Andreev quantum point contact

    Science.gov (United States)

    Kjaergaard, M.; Nichele, F.; Suominen, H.; Nowak, M.; Wimmer, M.; Akhmerov, A.; Folk, J.; Flensberg, K.; Shabani, J.; Palmstrom, C.; Marcus, C.

    One route to study the non-Abelian nature of excitations in topological superconductors is to realise gateable two dimensional (2D) semiconducting systems, with spin-orbit coupling in proximity to an s-wave superconductor. Previous work on coupling 2D electron gases (2DEG) with superconductors has been hindered by a non-ideal interface and unstable gateability. We report measurements on a gateable 2DEG coupled to superconductors through a pristine interface, and use aluminum grown in situ epitaxially on an InGaAs/InAs electron gas. We demonstrate quantization in units of 4e2 / h in a quantum point contact (QPC) in such hybrid systems. Operating the QPC as a tunnel probe, we observe a hard superconducting gap, overcoming the soft-gap problem in 2D superconductor/semiconductor systems. Our work paves way for a new and highly scalable system in which to pursue topological quantum information processing. Research supported by Microsoft Project Q and the Danish National Research Foundation.

  15. Entropy inequalities from reflection positivity

    International Nuclear Information System (INIS)

    Casini, H

    2010-01-01

    We investigate the question of whether the entropy and the Renyi entropies of the vacuum state reduced to a region of space can be represented in terms of correlators in quantum field theory. In this case, the positivity relations for the correlators are mapped into inequalities for the entropies. We write them using a real-time version of reflection positivity, which can be generalized to general quantum systems. Using this generalization we can prove an infinite sequence of inequalities which are obeyed by the Renyi entropies of integer index. There is one independent inequality involving any number of different subsystems. In quantum field theory the inequalities acquire a simple geometrical form and are consistent with the integer index Renyi entropies being given by vacuum expectation values of twisting operators in the Euclidean formulation. Several possible generalizations and specific examples are analyzed

  16. Reflections in the clinical practice.

    Science.gov (United States)

    Borrell-Carrió, F; Hernández-Clemente, J C

    2014-03-01

    The purpose of this article is to analyze some models of expert decision and their impact on the clinical practice. We have analyzed decision-making considering the cognitive aspects (explanatory models, perceptual skills, analysis of the variability of a phenomenon, creating habits and inertia of reasoning and declarative models based on criteria). We have added the importance of emotions in decision making within highly complex situations, such as those occurring within the clinical practice. The quality of the reflective act depends, among other factors, on the ability of metacognition (thinking about what we think). Finally, we propose an educational strategy based on having a task supervisor and rectification scenarios to improve the quality of medical decision making. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  17. Microdosimetry: Reflections on Harald Rossi

    International Nuclear Information System (INIS)

    Kellerer, A.M.

    2002-01-01

    This and twelve previous Symposia reflect the evolution of microdosimetry, a field of research that has determined major new developments in radiation research, radiation protection, and radiology during the past four decades. The concepts of microdosimetry and its techniques were developed almost single handedly by H.H. Rossi. This memorial lecture outlines some of the ideas and some of the work of Harald Rossi that led to microdosimetry. It describes its major impact on radiobiology and, especially, its impact on studies with fast neutrons and on risk assessment. Microdosimetry was primarily designed as a tool for the elucidation of basic mechanisms of radiation action, but it has found its most important applications in the dosimetric measurement techniques that have become indispensable in radiation protection and in the dosimetry for radiation therapy. The advances of molecular biology are now providing new possibilities for a quantitative application of microdosimetry to radiobiology along the lines that Harald Rossi defined. (author)

  18. Reflecting on Normative Power Europe

    DEFF Research Database (Denmark)

    Diez, Thomas; Manners, Ian James

    2014-01-01

    -interested geographical expansion or military superiority. In the 1970s, François Duchêne called it a ‘civilian power’ (1972: 43); in the early 2000s it was argued that the label ‘normative power’ would be better suited (Manners 2000, 2002). Just as Duchêne’s civilian power reflected the Cold War milieu of the 1970s......There is a widespread belief that the European Union (EU) is a novel kind of power not only in its own institutional set-up but also in its external relations. It is said to rely on civilian rather than military means and to pursue the spread of particular norms rather than self......, the normative power approach signified a crystallisation of the EU in the post-Cold War era....

  19. Temporal reflectance changes in vegetables

    DEFF Research Database (Denmark)

    Dissing, Bjørn Skovlund; Clemmensen, Line Katrine Harder; Ersbøll, Bjarne Kjær

    2009-01-01

    Quality control in the food industry is often performed by measuring various chemical compounds of the food involved. We propose an imaging concept for acquiring high quality multispectral images to evaluate changes of carrots and celeriac over a period of 14 days. Properties originating...... in the surface chemistry of vegetables may be captured in an integrating sphere illumination which enables the creation of detailed surface chemistry maps with a good combination of spectral and spatial resolutions. Prior to multispectral image recording, the vegetables were prefried and frozen at -30Â......°C for four months. During the 14 days of image recording, the vegetables were kept at +5°C in refrigeration. In this period, surface changes and thereby reflectance properties were very subtle. To describe this small variation we employed advanced statistical techniques to search a large featurespace...

  20. Cholesteric Liquid Crystal Based Reflex Color Reflective Displays

    Science.gov (United States)

    Khan, Asad

    2012-02-01

    Bistable color cholesteric liquid crystal displays are unique LCDs that exhibit high reflectivity, good contrast, extremely low power operation, and are amenable to versatile roll-to-roll manufacturing. The display technology, now branded as Reflex has been in commercialized products since 1996. It has been the subject of extensive research and development globally by a variety of parties in both academic and industrial settings. Today, the display technology is in volume production for applications such as dedicated eWriters (Boogie Board), full color electronic skins (eSkin), and displays for smart cards. The flexibility comes from polymerization induced phase separation using unique materials unparalleled in any other display technology. The blend of monomers, polymers, cross linkers, and other components along with nematic liquid crystals and chiral dopants is created and processed in such ways so as to enable highly efficient manufactrable displays using ultra thin plastic substrates -- often as thin as 50μm. Other significant aspects include full color by stacking or spatial separation, night vision capability, ultra high resolution, as well as active matrix capabilities. Of particular note is the stacking approach of Reflex based displays to show full color. This approach for reflective color displays is unique to this technology. Owing to high transparency in wavelength bands outside the selective reflection band, three primarily color layers can be stacked on top of each other and reflect without interfering with other layers. This highly surprising architecture enables the highest reflectivity of any other reflective electronic color display technology. The optics, architecture, electro-topics, and process techniques will be discussed. This presentation will focus on the physics of the core technology and color, it's evolution from rigid glass based displays to flexible displays, development of products from the paradigm shifting concepts to consumer

  1. Reflection of neutrons from a helicoidal system

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Ignatovich, V.K.; Nikitenko, Yu.V.

    2006-01-01

    Analytical solution for neutron reflection and transmission of magnetic mirrors with helicoidal magnetization is found. The dependence of neutron speed of reflection and transmission curves is shown. Resonant properties of helicoidal systems are found

  2. Reflection in Medical Diagnosis: A Literature Review

    OpenAIRE

    Mamede, Silvia; Schmidt, Henk G.

    2017-01-01

    Purpose: Reflection in medical diagnosis has been said to prevent errors by minimizing flaws in clinical reasoning. This claim, however, has been much disputed. While some studies show reflective reasoning to improve diagnostic performance, others find it to add nothing. This paper presents a narrative review of the literature on reflection in medical diagnosis aimed at addressing two questions: (1) how reflective reasoning has been conceived in this literature; and (2) what is the effect of ...

  3. Effectuation And Reflection-In-Action

    DEFF Research Database (Denmark)

    Gertsen, Frank; Lervang, Johan-Ulrik; Maack, Karl

    2013-01-01

    Our main aim is to facilitate a reflective methodology for MSc thesis students in practical entrepreneurship that draws on the ideas of ‘reflection-in-action’ while simultaneously making use of the effectuation logics.......Our main aim is to facilitate a reflective methodology for MSc thesis students in practical entrepreneurship that draws on the ideas of ‘reflection-in-action’ while simultaneously making use of the effectuation logics....

  4. FEMA DFIRM Cross Sections

    Data.gov (United States)

    Minnesota Department of Natural Resources — FEMA Cross Sections are required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally...

  5. Border Crossing Entry Data

    Data.gov (United States)

    Department of Transportation — The Bureau of Transportation Statistics (BTS) Border Crossing/Entry Data provides summary statistics for inbound crossings at the U.S.-Canadian and the U.S.-Mexican...

  6. Gradient metasurface for four-direction anomalous reflection in terahertz

    Science.gov (United States)

    Wang, Jiao; Jiang, Yannan

    2018-06-01

    In this paper, a four-direction anomalous reflection metasurface is proposed. The basic cells comprise of squares and circles, which are designed at various sizes and arranged in a super cell at regular spacing. Then, properly combining super cells molds a square phase gradient metasurface (PGM). It is mounted on an optical thickness gold mirror, which inhibits all light transmission. Markedly different from previously reported metasurfaces, the square PGM is characterized by four-direction reflection beams. It takes into consideration the normal incidence and the oblique incidence. For the normal incidence, that the degrees of the four reflection angles are identical is due to the x, - x, y and - y directional discontinuous phase gradients, and lies on the symmetric structure in the xoy plane, which is then revealed by the surface current distribution. Incident angles varying from -20° to 20°, the reflection angles are demonstrated in the oblique incidence. Moreover, the PGM is polarization-independent. The performance is attributed to the symmetry of structure, which is verified by Radar cross section. Simulated results prove that our method offers a simple and effective strategy for metasurface design in terahertz. The proposed PGM can aid in focused beams, steering beams, and shaped beams.

  7. Selective reflection of resonance radiation from excited media

    International Nuclear Information System (INIS)

    Veklenko, B.A.; Gusarov, R.B.; Sherkunov, Yu.B.

    1998-01-01

    According to quantum electrodynamics, the cross section for resonant scattering of radiation on an aggregate of excited atoms can be written as a sum of positive definite terms. This type of structure is not consistent with the Fresnel formulas for the reflection coefficient of radiation from thermally excited media. The difference shows up on a macroscopic level and indicates that semiclassical radiation theory cannot be used. A study of the correlation between elastic scattering and stimulated emission processes clarifies the reason for the discrepancies. The resulting singularities require summing of Feynman diagrams which appear beginning in the sixth order of perturbation theory. A lower bound estimate for the reflection coefficient from a plane layer is given, including processes which violate the statistics of radiation. The contribution of stimulated emission processes caused by the initially scattered photon are examined specifically. An experiment is proposed which would settle the choice of theories

  8. The role of emotion in design reflection

    NARCIS (Netherlands)

    Hammer, D.K.; Reymen, I.M.M.J.; Mcdonagh, Deana; Hekkert, Paul; Van Erp, Jeroen; Gyi, Diane

    2003-01-01

    Reflection on design processes performed by designers is called design reflection. In our view, this kind of reflection aims at answering essential questions like “Is my design answering the stakeholder concerns?”, “Am I solving the essential problems or am I wasting time on irrelevant aspects?”,

  9. Historical Text Comprehension Reflective Tutorial Dialogue System

    Science.gov (United States)

    Grigoriadou, Maria; Tsaganou, Grammatiki; Cavoura, Theodora

    2005-01-01

    The Reflective Tutorial Dialogue System (ReTuDiS) is a system for learner modelling historical text comprehension through reflective dialogue. The system infers learners' cognitive profiles and constructs their learner models. Based on the learner model the system plans the appropriate--personalized for learners--reflective tutorial dialogue in…

  10. Reflection during Portfolio-Based Conversations

    Science.gov (United States)

    Oosterbaan, Anne E.; van der Schaaf, Marieke F.; Baartman, Liesbeth K. J.; Stokking, Karel M.

    2010-01-01

    This study aims to explore the relationship between the occurrence of reflection (and non-reflection) and thinking activities (e.g., orientating, selecting, analysing) during portfolio-based conversations. Analysis of 21 transcripts of portfolio-based conversations revealed that 20% of the segments were made up of reflection (content reflection…

  11. Reflection and Reasoning in Moral Judgment

    Science.gov (United States)

    Paxton, Joseph M.; Ungar, Leo; Greene, Joshua D.

    2012-01-01

    While there is much evidence for the influence of automatic emotional responses on moral judgment, the roles of reflection and reasoning remain uncertain. In Experiment 1, we induced subjects to be more reflective by completing the Cognitive Reflection Test (CRT) prior to responding to moral dilemmas. This manipulation increased utilitarian…

  12. Enabling Critical Reflection on Research Supervisory Practice

    Science.gov (United States)

    Pearson, Margot; Kayrooz, Carole

    2004-01-01

    This paper describes the development of an instrument--The Reflective Supervisor Questionnaire (RSQ). The RSQ maps the domain of research supervisory practice as a facilitative process involving educational tasks and activities. It is designed to assist research supervisors explore, by means of self-reflection and reflection on feedback from…

  13. Reflective Journals: A Review of the Literature

    Science.gov (United States)

    Lindroth, James T.

    2015-01-01

    The use of reflective journals has been identified as an effective tool to promote reflection in preservice teachers. This review of literature provides the reader with an understanding of the various ways journals are used and assessed in teacher education programs. The findings of this review outline the use of reflective journals on topics such…

  14. Improving Teaching through Collaborative Reflective Teaching Cycles

    Science.gov (United States)

    Murray, Eileen

    2015-01-01

    Reflection and collaboration are two activities teachers can use to change and improve their practice. However, finding the time and space to do so can be challenging. The collaborative reflective teaching cycle is a structured activity teachers can use to engage in reflection and collaboration. This article describes how a seventh grade teaching…

  15. Developing Mathematical Practices through Reflection Cycles

    Science.gov (United States)

    Reinholz, Daniel L.

    2016-01-01

    This paper focuses on reflection in learning mathematical practices. While there is a long history of research on reflection in mathematics, it has focused primarily on the development of conceptual understanding. Building on notion of learning as participation in social practices, this paper broadens the theory of reflection in mathematics…

  16. Improving Inquiry Teaching through Reflection on Practice

    Science.gov (United States)

    Lotter, Christine R.; Miller, Cory

    2017-08-01

    In this paper, we explore middle school science teachers' learning of inquiry-based instructional strategies through reflection on practice teaching sessions during a summer enrichment program with middle level students. The reflection sessions were part of a larger year-long inquiry professional development program in which teachers learned science content and inquiry pedagogy. The program included a 2-week summer institute in which teachers participated in science content sessions, practice teaching to middle level students, and small group-facilitated reflection sessions on their teaching. For this study, data collection focused on teachers' recorded dialogue during the facilitator - run reflection sessions, the teachers' daily written reflections, a final written reflection, and a written reflection on a videotaped teaching session. We investigated the teachers' reflection levels and the themes teachers focused on during their reflection sessions. Teachers were found to reflect at various reflection levels, from simple description to a more sophisticated focus on how to improve student learning. Recurrent themes point to the importance of providing situated learning environments, such as the practice teaching with immediate reflection for teachers to have time to practice new instructional strategies and gain insight from peers and science educators on how to handle student learning issues.

  17. Superconvergent sum rules for the normal reflectivity

    International Nuclear Information System (INIS)

    Furuya, K.; Zimerman, A.H.; Villani, A.

    1976-05-01

    Families of superconvergent relations for the normal reflectivity function are written. Sum rules connecting the difference of phases of the reflectivities of two materials are also considered. Finally superconvergence relations and sum rules for magneto-reflectivity in the Faraday and Voigt regimes are also studied

  18. Design, Analysis, and On-Sun Evaluation of Reflective Strips Under Controlled Buckling

    Science.gov (United States)

    Jaworske, Donald A.; Sechkar, Edward A.; Colozza, Anthony J.

    2014-01-01

    Solar concentrators are envisioned for use in a variety of space-based applications, including applications involving in situ resource utilization. Identifying solar concentrators that minimize mass and cost are of great interest, especially since launch cost is driven in part by the mass of the payload. Concentrators must also be able to survive the wide temperature excursions on the lunar surface. Identifying smart structures which compensate for changes in concentrator geometry brought about by temperature extremes are of interest. Some applications may benefit from the ability to change the concentrators focal pattern at will. This paper addresses a method of designing a single reflective strip to produce a desired focal pattern through the use of controlled buckling. Small variations in the cross section over the length of the reflective strip influence the distribution of light in the focal region. A finite element method of analysis is utilized here which calculates the curve produced for a given strip cross section and axial load. Varying axial force and strip cross section over the length of the reflective strip provide a means of optimizing ray convergence in the focal region. Careful selection of a tapered cross section yields a reflective strip that approximates a parabola. An array of reflective strips under controlled buckling produces a light weight concentrator and adjustments in the compression of individual strips provide a means of compensating for temperature excursions or changing the focal pattern at will.

  19. Daytime Water Detection Based on Sky Reflections

    Science.gov (United States)

    Rankin, Arturo; Matthies, Larry; Bellutta, Paolo

    2011-01-01

    A water body s surface can be modeled as a horizontal mirror. Water detection based on sky reflections and color variation are complementary. A reflection coefficient model suggests sky reflections dominate the color of water at ranges > 12 meters. Water detection based on sky reflections: (1) geometrically locates the pixel in the sky that is reflecting on a candidate water pixel on the ground (2) predicts if the ground pixel is water based on color similarity and local terrain features. Water detection has been integrated on XUVs.

  20. Beyond the Margins: Reflective Writing and Development of Reflective Capacity in Medical Education

    Science.gov (United States)

    Reis, Shmuel P.

    2010-01-01

    Reflective capacity has been described as an essential characteristic of professionally competent clinical practice, core to ACGME competencies. Reflection has been recently linked to promoting effective use of feedback in medical education and associated with improved diagnostic accuracy, suggesting promising outcomes. There has been a proliferation of reflective writing pedagogy within medical education to foster development of reflective capacity, extend empathy with deepened understanding of patients’ experience of illness, and promote practitioner well-being. At Alpert Med, “interactive” reflective writing with guided individualized feedback from interdisciplinary faculty to students’ reflective writing has been implemented in a Doctoring course and Family Medicine clerkship as an educational method to achieve these aims. Such initiatives, however, raise fundamental questions of reflection definition, program design, efficacy of methods, and outcomes assessment. Within this article, we consider opportunities and challenges associated with implementation of reflective writing curricula for promotion of reflective capacity within medical education. We reflect upon reflection. PMID:20407840

  1. Theory of reflection reflection and transmission of electromagnetic, particle and acoustic waves

    CERN Document Server

    Lekner, John

    2016-01-01

    This book deals with the reflection of electromagnetic and particle waves by interfaces. The interfaces can be sharp or diffuse. The topics of the book contain absorption, inverse problems, anisotropy, pulses and finite beams, rough surfaces, matrix methods, numerical methods,  reflection of particle waves and neutron reflection. Exact general results are presented, followed by long wave reflection, variational theory, reflection amplitude equations of the Riccati type, and reflection of short waves. The Second Edition of the Theory of Reflection is an updated and much enlarged revision of the 1987 monograph. There are new chapters on periodically stratified media, ellipsometry, chiral media, neutron reflection and reflection of acoustic waves. The chapter on anisotropy is much extended, with a complete treatment of the reflection and transmission properties of arbitrarily oriented uniaxial crystals. The book gives a systematic and unified treatment reflection and transmission of electromagnetic and particle...

  2. Do writing and storytelling skill influence assessment of reflective ability in medical students' written reflections?

    Science.gov (United States)

    Aronson, Louise; Niehaus, Brian; DeVries, Charlie D; Siegel, Jennifer R; O'Sullivan, Patricia S

    2010-10-01

    Increasingly, students are asked to write reflections as part of their medical education, but some question the influence of other factors on the evaluation of these reflections. In this pilot study, the investigators determined whether scores from a validated rubric to measure reflective ability were affected by irrelevant variance resulting from writing or storytelling ability. Students in clerkships wrote reflections on professionalism. All were given identical prompts, with half receiving additional structured guidelines on reflection. Sixty reflections, 30 from each group, were randomly chosen and scored for reflection, writing, and storytelling by trained raters using validated rubrics. There was no correlation between reflection and either writing (r = 0.049, P = .35) or storytelling (r = 0.14, P = .13). The guidelines increased reflection, but not writing or storytelling scores. Reflection is a distinct construct unaffected by learners' writing or storytelling skills. These findings support reflective ability as a distinct skill.

  3. Interpreting Electromagnetic Reflections In Glaciology

    Science.gov (United States)

    Eisen, O.; Nixdorf, U.; Wilhelms, F.; Steinhage, D.; Miller, H.

    Electromagnetic reflection (EMR) measurements are active remote sensing methods that have become a major tool for glaciological investigations. Although the basic pro- cesses are well understood, the unambiguous interpretation of EMR data, especially internal layering, still requires further information. The Antacrtic ice sheet provides a unique setting for investigating the relation between physical­chemical properties of ice and EMR data. Cold ice, smooth surface topography, and low accumulation facilitates matters to use low energy ground penetrating radar (GPR) devices to pene- trate several tens to hundreds of meters of ice, covering several thousands of years of snow deposition history. Thus, sufficient internal layers, primarily of volcanic origin, are recorded to enable studies on a local and regional scale. Based on dated ice core records, GPR measurements at various frequencies, and airborne radio-echo sound- ing (RES) from Dronning Maud Land (DML), Antarctica, combined with numerical modeling techniques, we investigate the influence of internal layering characteristics and properties of the propagating electromagnetic wave on EMR data.

  4. Filmography to reflect on retirement

    Directory of Open Access Journals (Sweden)

    María de los Ángeles AGUILERA VELASCO

    2018-03-01

    Full Text Available A documentary compilation of films about retirement was made. The data of films, in language or subtitles in Spanish, that had an argument related to retirement or that their protagonists evidenced experiences of the retirement were included. The documentary compilation was made through the stages of search and analysis. 54 films were found and organized into nine categories. The oldest film was from 1924 and the most recent of 2017. 61.11% of films were made as of 2010. In five films (9.25% the protagonists wanted to commit suicide when leaving work. Euthanasia (5.55% was performed in three films (5.55%. The problem of retirement in women was found only in four films (7.49%. In 18 films (33.33% the male protagonists went through widowhood. Twenty-one countries participated in productions, the United States produced 21 films (38.88%. It provides a very extensive collection of valuable films that convey great lessons, allow us to reflect and raise awareness of this stage of life. It is recommended to socialize the films through socio-educational interventions and investigations, as well as to begin to inquire scientifically about the relationship between suicide and euthanasia in retirement.

  5. REFLECTIONS ON SCREENAGERS, FACULTY DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Mike K. MOULTON

    2008-04-01

    Full Text Available This paper outlines a strategy for a faculty development program with respect to net-supported learning. Many universities and colleges are struggling with meeting the demands of a rapidly changing world. Reflections in this paper are based on experiences from the Norwegian University of Life Sciences. Attention has been given to the intelligent use of technology as a means of meeting pressing challenges. What does this mean? I ask a series of questions, the answers of which form the basis for a faculty development program. What qualities and skills should our graduates have? What consequences does this have for the way we approach teaching and learning? And what role does technology play? In short, we must focus on faculty training courses and the ensuing development cycles of trial, error, refinement and sharing. Guiding principles for these activities should be:1. It is about learning.2. It is about easy access.3. It is about emphasizing collaboration.4. It is about support.

  6. Reflection asymmetric shapes in nuclei

    International Nuclear Information System (INIS)

    Ahmad, I.; Carpenter, M.P.; Emling, H.

    1989-01-01

    Experimental data show that there is no even-even nucleus with a reflection asymmetric shape in its ground state. Maximum octupole- octupole correlations occur in nuclei in the mass 224 (N∼134, Z∼88) region. Parity doublets, which are the characteristic signature of octupole deformation, have been observed in several odd mass Ra, Ac and Pa nuclei. Intertwined negative and positive parity levels have been observed in several even-even Ra and Th nuclei above spin ∼8ℎ. In both cases, the opposite parity states are connected by fast El transitions. In some medium-mass nuclei intertwined negative and positive parity levels have also been observed above spin ∼7ℎ. The nuclei which exhibit octupole deformation in this mass region are 144 Ba, 146 Ba and 146 Ce; 142 Ba, 148 Ce, 150 Ce and 142 Xe do not show these characteristics. No case of parity doublet has been observed in the mass 144 region. 32 refs., 16 figs., 1 tab

  7. A Feminist Reflection on Citizenship

    Directory of Open Access Journals (Sweden)

    Virginia Vargas Valente

    2000-01-01

    Full Text Available Over the course of the past decade, citizenship has become one of the axes of feminist action and reflection in Latin America, and, at the same time, it is at the core of democratic concerns at the national levels and, as never before, at the global level. Citizenship constitutes an important pole in women's long fight for equality, lending new democratic content to feminist debates. It also is a meaningful axis for generating alliances among women and between women and other social groups, with the aim of broadening the limits of citizenship restrained by the manifold discriminations in our societies. Citizenship is a terrain of dispute between civil society and the state, and also within civil society itself. Feminist theorists of citizenship are adding complexity and contributing to a theory of citizenship by pointing to incongruities and weaknesses in the concept and practice of citizenship, recognizing that differences - not only gender-based ones- but among women themselves, may present possibilities and obstacles which need to be enhanced or neutralized.

  8. Self-reflection, gender and science achievement

    Science.gov (United States)

    Shoop, Kathleen A.

    Drawing on socio-cognitive learning theory, this study compared achievement scores of 134 male and female high school biology students randomly assigned to groups which either used self-reflection, used self-reflection and received feedback, or did not self-reflect. Following a pretest, the teacher provided self-reflection strategy instruction to students in the two intervention groups and then subsequently provided in-class self-reflection time for these groups. The posttest concluded the unit; the retention measure was five weeks later. A quasi-experimental 3 x 3 x 2 (time x intervention x gender) factorial repeated-measures control group design was used for this study; a repeated measures ANOVA and several one-way ANOVA's were used to answer the research questions. Results from the repeated-measures ANOVA revealed significant results for Time and Time x Intervention, with the reflection group demonstrating significantly lower gains from pretest to posttest than the other two groups. The ANOVA examining differences between those who reflected and those who reflected and received feedback provided significant results with similar results for the difference between the control group and the reflection group. For teachers and students this study provides several areas of practical significance. Primarily, teachers may find lower student achievement if students regularly self-reflect but do not receive feedback for their reflection.

  9. Terahertz radar cross section measurements.

    Science.gov (United States)

    Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd

    2010-12-06

    We perform angle- and frequency-resolved radar cross section (RCS) measurements on objects at terahertz frequencies. Our RCS measurements are performed on a scale model aircraft of size 5-10 cm in polar and azimuthal configurations, and correspond closely to RCS measurements with conventional radar on full-size objects. The measurements are performed in a terahertz time-domain system with freely propagating terahertz pulses generated by tilted pulse front excitation of lithium niobate crystals and measured with sub-picosecond time resolution. The application of a time domain system provides ranging information and also allows for identification of scattering points such as weaponry attached to the aircraft. The shapes of the models and positions of reflecting parts are retrieved by the filtered back projection algorithm.

  10. Diffuse and localized reflectance measurements of hemoglobin and hematocrit in human skin

    Science.gov (United States)

    Khalil, Omar S.; Wu, Xiaomao; Yeh, Shu-Jen; Jeng, Tzyy-Wen

    2001-05-01

    We conducted visible/near infrared optical measurements on the forearm of human subjects using a commercial diffuse reflectance spectrophotometer, and a breadboard temperature- controlled localized reflectance tissue photometer. Calibration relationships were established between skin reflectance signal and reference blood hemoglobin (Hb) concentration, or hematocrit values (Hct). These were then used to predict Hb and Hct values from optical measurement in a cross validation analysis. Different linear least- squares models for the prediction of Hb and Hct are presented and shows the ability to predict both. It was possible to screen prospective blood donors with low Hb concentration. It was possible to predict anemic subjects in the limited prospective blood donor population.

  11. GHOSTLY REFLECTIONS IN THE PLEIADES

    Science.gov (United States)

    2002-01-01

    NASA's Hubble Space Telescope has caught the eerie, wispy tendrils of a dark interstellar cloud being destroyed by the passage of one of the brightest stars in the Pleiades star cluster. Like a flashlight beam shining off the wall of a cave, the star is reflecting light off the surface of pitch black clouds of cold gas laced with dust. These are called reflection nebulae. The famous cluster is easily visible in the evening sky during the winter months as a small grouping of bright blue stars, named after the 'Seven Sisters' of Greek mythology. Resembling a small dipper, this star cluster lies in the constellation Taurus at a distance of about 380 light-years from Earth. The unaided eye can discern about half a dozen bright stars in the cluster, but a small telescope will reveal that the Pleiades contains many hundreds of fainter stars. In many cases, the nebulae surrounding star clusters represent material from which the stars have formed recently. However the Pleiades nebulosity is actually an independent cloud, drifting through the cluster at a relative speed of about 6.8 miles/second (11 kilometers/second). In 1890, American astronomer E. E. Barnard, observing visually with the Lick Observatory 36-inch telescope in California, discovered an exceptionally bright nebulosity adjacent to the bright Pleiades star Merope. It is now cataloged as IC 349, or 'Barnard's Merope Nebula.' IC 349 is so bright because it lies extremely close to Merope--only about 3,500 times the separation of the Earth from the Sun, or about 0.06 light-year--and thus is strongly illuminated by the star's light. In the new Hubble image, Merope itself is just outside the frame on the upper right. The colorful rays of light at the upper right, pointing back to the star, are an optical phenomenon produced within the telescope, and are not real. However, the remarkable parallel wisps extending from lower left to upper right are real features, revealed for the first time through Hubble's high

  12. Designing a Reflective Teacher Education Course and Its Contribution to ELT Teachers' Reflectivity

    Science.gov (United States)

    Tajik, Leila; Pakzad, Kazem

    2016-01-01

    Researchers in the present study planned a reflective teacher education course and documented the contribution of such a course to improving teachers' reflectivity. Five English teachers took part in the reflective teacher education course designed by the researchers. To record how the course could help improve reflective teaching, researchers…

  13. An Access Control Framework for Reflective Middleware

    Institute of Scientific and Technical Information of China (English)

    Gang Huang; Lian-Shan Sun

    2008-01-01

    Reflective middleware opens up the implementation details of middleware platform and applications at runtime for improving the adaptability of middleware-based systems. However, such openness brings new challenges to access control of the middleware-based systems.Some users can access the system via reflective entities, which sometimes cannot be protected by access control mechanisms of traditional middleware. To deliver high adaptability securely, reflective middleware should be equipped with proper access control mechanisms for potential access control holes induced by reflection. One reason of integrating these mechanisms in reflective middleware is that one goal of reflective middleware is to equip applications with reflection capabilities as transparent as possible. This paper studies how to design a reflective J2EE middlewarePKUAS with access control in mind. At first, a computation model of reflective system is built to identify all possible access control points induced by reflection. Then a set of access control mechanisms, including the wrapper of MBeans and a hierarchy of Java class loaders, are equipped for controlling the identified access control points. These mechanisms together with J2EE access control mechanism form the access control framework for PKUAS. The paper evaluates the security and the performance overheads of the framework in quality and quantity.

  14. Perioperative self-reflection among surgical residents.

    Science.gov (United States)

    Peshkepija, Andi N; Basson, Marc D; Davis, Alan T; Ali, Muhammad; Haan, Pam S; Gupta, Rama N; Hardaway, John C; Nebeker, Cody A; McLeod, Michael K; Osmer, Robert L; Anderson, Cheryl I

    2017-09-01

    We studied prevalence and predictors of meaningful self-reflection among surgical residents and with prompting/structured interventions, sought to improve/sustain resident skills. Residents from six programs recorded 1032 narrative self-reflective comments (120 residents), using a web-based platform. If residents identified something learned or to be improved, self-reflection was deemed meaningful. Independent variables PGY level, resident/surgeon gender, study site/Phase1: July2014-August2015 vs. Phase2: September2015-September2016) were analyzed. Meaningful self-reflection was documented in 40.6% (419/1032) of entries. PGY5's meaningfully self-reflected less than PGY1-4's, 26.1% vs. 49.6% (p = 0.002). In multivariate analysis, resident narratives during Phase 2 were 4.7 times more likely to engage in meaningful self-reflection compared to Phase1 entries (p self-reflection, compared to Phase1. Surgical residents uncommonly practice meaningful self-reflection, even when prompted, and PGY5/chief residents reflect less than more junior residents. Substantial/sustained improvements in resident self-reflection can occur with both training and interventions. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Nonlocal thermoelectric symmetry relations in ferromagnet-superconductor proximity structures

    Energy Technology Data Exchange (ETDEWEB)

    Machon, Peter; Belzig, Wolfgang [Department of Physics, University of Konstanz, D-78457 Konstanz (Germany); Eschrig, Matthias [Department of Physics, University of Konstanz, D-78457 Konstanz (Germany); Department of Physics, Royal Holloway, University of London, Egham Hill, EGHAM, TW20 0EX (United Kingdom)

    2012-07-01

    The symmetries of thermal and electric transport coefficients in quantum coherent structures are related to fundamental thermodynamic principles by the Onsager reciprocity. We generalize Onsager's symmetry relation to nonlocal thermoelectric currents in a three terminal ferromagnet-superconductor heterostructure including spin-dependent crossed Andreev reflection and direct electron transfer processes. We proof this general symmetry by applying spin-dependent boundary conditions for quasi-classical Green's functions in both the clean and the dirty limit. We predict an anomalously large local thermopower and a nonlocal Seebeck effect, which can be explained by the spin-dependent spectral properties.

  16. Evaluation of retro-reflective coating performance by reflectance and perceived relative brightness measurements

    Energy Technology Data Exchange (ETDEWEB)

    Luse, Kaiva; Pausus, Anete; Karitans, Varis; Ozolins, Maris; Tukisa, Madara, E-mail: kaiva.luse@gmail.com [University of Latvia, Optometry and Vision Science Department, Kengaraga street 8, Riga LV-1063 (Latvia)

    2011-06-23

    Retro-reflective properties of six types and five different colors or retro-reflective materials were discussed in this paper. Reflectance optical indicatrix of samples was determined and compared to obtained psychophyisical data of perceived brightness of human observer. Microscopic structure of the retro-reflective active regions of RR's was studied. Statistically significant differences in reflectivity and brightness of various types and colors of RR's were found.

  17. Evaluation of retro-reflective coating performance by reflectance and perceived relative brightness measurements

    International Nuclear Information System (INIS)

    Luse, Kaiva; Pausus, Anete; Karitans, Varis; Ozolins, Maris; Tukisa, Madara

    2011-01-01

    Retro-reflective properties of six types and five different colors or retro-reflective materials were discussed in this paper. Reflectance optical indicatrix of samples was determined and compared to obtained psychophyisical data of perceived brightness of human observer. Microscopic structure of the retro-reflective active regions of RR's was studied. Statistically significant differences in reflectivity and brightness of various types and colors of RR's were found.

  18. Changes in brain morphology in albinism reflect reduced visual acuity.

    Science.gov (United States)

    Bridge, Holly; von dem Hagen, Elisabeth A H; Davies, George; Chambers, Claire; Gouws, Andre; Hoffmann, Michael; Morland, Antony B

    2014-07-01

    Albinism, in humans and many animal species, has a major impact on the visual system, leading to reduced acuity, lack of binocular function and nystagmus. In addition to the lack of a foveal pit, there is a disruption to the routing of the nerve fibers crossing at the optic chiasm, resulting in excessive crossing of fibers to the contralateral hemisphere. However, very little is known about the effect of this misrouting on the structure of the post-chiasmatic visual pathway, and the occipital lobes in particular. Whole-brain analyses of cortical thickness in a large cohort of subjects with albinism showed an increase in cortical thickness, relative to control subjects, particularly in posterior V1, corresponding to the foveal representation. Furthermore, mean cortical thickness across entire V1 was significantly greater in these subjects compared to controls and negatively correlated with visual acuity in albinism. Additionally, the group with albinism showed decreased gyrification in the left ventral occipital lobe. While the increase in cortical thickness in V1, also found in congenitally blind subjects, has been interpreted to reflect a lack of pruning, the decreased gyrification in the ventral extrastriate cortex may reflect the reduced input to the foveal regions of the ventral visual stream. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. CVD molybdenum films of high infrared reflectance

    Energy Technology Data Exchange (ETDEWEB)

    Carver, G. E.

    1979-01-01

    Molybdenum thin films of high infrared reflectance have been deposited by pyrolytic decomposition of molybdenum carbonyl (Mo(CO)/sub 6/), and by hydrogen reduction of molybdenum pentachloride (MoCl/sub 5/). Reflectance values within 0.7% of the reflectance of supersmooth bulk molybdenum have been attained by annealing films of lower reflectance in both reducing and non-reducing atmospheres. All depositions and anneals proceed at atmospheric pressure, facilitating a continuous, flow-through fabrication. These reflectors combine the high temperature stability of molybdenum thin films with the infrared reflectance of a material such as aluminum. Deposition from Mo(CO)/sub 6/ under oxidizing conditions, and subsequent anneal in a reducing atmosphere, results in films that combine high solar absorptance with low thermal emittance. If anti-reflected, black molybdenum films can serve as highly selective single layer photothermal converters. Structural, compositional, and crystallographic properties have been measured after both deposition and anneal.

  20. Re-thinking reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    The paper presents a socio-cultural perspective on supervision in professional education, which challenges the current reflective paradigm and move the debate on reflection in supervision in professional education and learning towards a recognition of context, power dynamics and ideological...... of reflective practice has been formalized by regulatory bodies as a way to develop the professionalism of both individual professional practitioners as students through continuing professional developmental processes. Consequently, reflection is often used as a `tool´ for personal and professional development...... al., 2010). This conceptual paper presents a critical, socio-cultural perspective on the current paradigm or dogma of reflective practice within supervision in professional education and learning. The purpose I to challenge the dogma and critically to analyze and move the debate on reflection...

  1. Cross Selling Management

    OpenAIRE

    Nufer, Gerd; Kelm, Daniel

    2011-01-01

    Erfolgreiches Cross Selling Management bietet die Möglichkeit, die Profitabilität von Neu- oder Bestandskunden zu steigern und kann zur Verbesserung der Kundenzufriedenheit, Kundenbindung und Verlängerung des Kundenlebenszyklus beitragen. Um erfolgreiches Cross Selling Management zu betreiben, sind ein systematisches Vorgehen und die Bereitstellung von Unternehmensressourcen notwendig. Umfangreiche vorbereitende Maßnahmen stellen sicher, dass Cross Selling nicht dem Zufall überlassen wird. De...

  2. Cross currency swap valuation

    OpenAIRE

    Boenkost, Wolfram; Schmidt, Wolfgang M.

    2004-01-01

    Cross currency swaps are powerful instruments to transfer assets or liabilities from one currency into another. The market charges for this a liquidity premium, the cross currency basis spread, which should be taken into account by the valuation methodology. We describe and compare two valuation methods for cross currency swaps which are based upon using two different discounting curves. The first method is very popular in practice but inconsistent with single currency swap valuation methods....

  3. Cross-Kerr nonlinearities in an optically dressed periodic medium

    Energy Technology Data Exchange (ETDEWEB)

    Slowik, K; Raczynski, A; Zaremba, J [Instytut Fizyki, Uniwersytet Mikolaja Kopernika, ulica Grudziadzka 5, 87-100 Torun (Poland); Zielinska-Kaniasty, S [Instytut Matematyki i Fizyki, Uniwersytet Technologiczno-Przyrodniczy, Aleja Prof. S Kaliskiego 7, 85-789 Bydgoszcz (Poland); Artoni, M [Department of Physics and Chemistry of Materials, CNR-INFM Sensor Lab, Brescia University and European Laboratory for Nonlinear Spectroscopy, Firenze (Italy); La Rocca, G C, E-mail: karolina@fizyka.umk.pl [Scuola Normale Superiore and CNISM, Pisa (Italy)

    2011-02-15

    Cross-Kerr nonlinearities are analyzed for two light beams propagating in an atomic medium in the tripod configuration, dressed by a strong standing-wave laser field that induces periodic optical properties. The reflection and transmission spectra as well as the phases of both the reflected and transmitted components of the two beams are analyzed theoretically with nonlinearities up to third order being taken into account. Ranges of parameters are sought in which the cross-Kerr effect can be used as the basis of the phase gate.

  4. Cognitive reflection vs. calculation in decision making

    OpenAIRE

    Sinayev, Aleksandr; Peters, Ellen

    2015-01-01

    Scores on the three-item Cognitive Reflection Test (CRT) have been linked with dual-system theory and normative decision making (Frederick, 2005). In particular, the CRT is thought to measure monitoring of System 1 intuitions such that, if cognitive reflection is high enough, intuitive errors will be detected and the problem will be solved. However, CRT items also require numeric ability to be answered correctly and it is unclear how much numeric ability vs. cognitive reflection contributes t...

  5. Cognitive Reflection Versus Calculation in Decision Making

    OpenAIRE

    Aleksandr eSinayev; Ellen ePeters

    2015-01-01

    Scores on the three-item Cognitive Reflection Test (CRT) have been linked with dual-system theory and normative decision making (Frederick, 2005). In particular, the CRT is thought to measure monitoring of System 1 intuitions such that, if cognitive reflection is high enough, intuitive errors will be detected and the problem will be solved. However, CRT items also require numeric ability to be answered correctly and it is unclear how much numeric ability vs. cognitive reflection contributes t...

  6. Positive Stress and Reflective Practice Among Entrepreneurs

    Directory of Open Access Journals (Sweden)

    Kati Tikkamäki

    2016-01-01

    Full Text Available While heavy stress loads seem an unavoidable aspect of entrepreneurship, the positive side of stress (often referred to as ‘eustress’ remains a neglected area of research. This paper contributes to entrepreneurship research by linking the research streams of eustress and reflective practice. As a tool for analysing and developing thoughts and actions, reflective practice plays an important role in the interpretative work essential to positive stress experiences. Following an overview of approaches to stress at work, eustress and reflective practice, the paper explores how entrepreneurs experience the role of positive stress and reflective practice in their work and describes the reflective tools utilized by entrepreneurs in promoting eustress. The research process was designed to support reflective dialogue among the 21 Finnish entrepreneurs from different fields who participated in the study, with results based mainly on qualitative interviews. Nine of the interviewed entrepreneurs also kept a positive stress diary, including a three-day physiological measurement analysing their heartbeat variability. The findings suggest that positive stress and reflective practice are intertwined in the experiences of entrepreneurs and illustrate the role of reflective practice as a crucial toolset for promoting positive stress, comprising six reflective tools: studying oneself, changing one’s point of view, putting things into perspective, harnessing a feeling of trust, regulating resources and engaging in dialogue. Individual reflective capabilities vary, and a theory-driven division of reflective practice into individual, social and contextual dimensions is considered useful in understanding those differences. The research offers a starting point for exploring how eustress and reflective practice affect the well-being of entrepreneurs

  7. THE VARIABLE REFLECTION NEBULA CEPHEUS A EAST

    International Nuclear Information System (INIS)

    Hodapp, Klaus W.; Bressert, Eli

    2009-01-01

    We report K'-band imaging observations of the reflection nebula associated with Cepheus A East covering the time interval from 1990 to 2004. Over this time the reflection nebula shows variations of flux distribution, which we interpret as the effect of inhomogeneous and varying extinction in the light path from the illuminating source HW2 to the reflection nebula. The obscuring material is located within typical distances of ∼ 10 AU from the illuminating source.

  8. A Data-Driven Reflectance Model

    OpenAIRE

    Matusik, Wojciech; Pfister, Hanspeter; Brand, Matt; McMillan, Leonard

    2003-01-01

    We present a generative model for isotropic bidirectional reflectance distribution functions (BRDFs) based on acquired reflectance data. Instead of using analytical reflectance models, we represent each BRDF as a dense set of measurements. This allows us to interpolate and extrapolate in the space of acquired BRDFs to create new BRDFs. We treat each acquired BRDF as a single high-dimensional vector taken from a space of all possible BRDFs. We apply both linear (subspace) and non-linear (manif...

  9. Crossed modules of racks

    OpenAIRE

    Crans, Alissa S.; Wagemann, Friedrich

    2014-01-01

    We generalize the notion of a crossed module of groups to that of a crossed module of racks. We investigate the relation to categorified racks, namely strict 2-racks, and trunk-like objects in the category of racks, generalizing the relation between crossed modules of groups and strict 2-groups. Then we explore topological applications. We show that by applying the rack-space functor, a crossed module of racks gives rise to a covering. Our main result shows how the fundamental racks associate...

  10. The Importance of Reflective Practice in Nursing

    Directory of Open Access Journals (Sweden)

    Lauren Caldwell

    2013-01-01

    Full Text Available Reflection is an essential attribute for the development of autonomous, critical, and advanced practitioners (Mantzoukas & Jasper, 2004. According to Chong (2009, “Reflective practice should be a continuous cycle in which experience and reflection on experiences are inter-related” (p. 112. Studies have shown that nurses who take the time to reflect on their daily experiences provide enhanced nursing care, have a better understanding of theiractions, which in return develops their professional skills (Hansebo & Kihlgren, 2001. Reflective practice is the ability to examine ones actions and experiences with the outcome of developing their practice and enhancing clinicalknowledge. Reflective practice affects all levels of nursing, from students, to advanced practice nursing students, aswell as practicing nurses. Reflective practice is an important component of the nursing curriculum. Research has shown the relationship between student nurses and their mentors is vital. In order for reflection to be effective open-mindedness, courage, and a willingness to accept, and act on, criticism must be present (Bulmam, Lathlean, & Gobbi, 2012. This paper will explore the current literature and implications related to reflective practice in nursing.

  11. Layered magnets: polarized neutron reflection studies

    Energy Technology Data Exchange (ETDEWEB)

    Zabel, H; Schreyer, A [Ruhr-Univ. Bochum, Lehrstuhl fuer Experimentalphysik/Festkoerperphysik, Bochum (Germany)

    1996-11-01

    Neutron reflectivity measurements from extended surfaces, thin films and superlattices provide information on the chemical profile parallel to the film normal, including film thicknesses, average composition and interfacial roughness parameters. Reflectivity measurements with polarized neutrons are particularly powerful for analyzing the magnetic density profiles in thin films and superlattices in addition to chemical profiles. The basic theory of polarized neutron reflectivity is provided, followed by some examples and more recent applications concerning polarized neutron reflectivity studies from exchange coupled Fe/Cr superlattices. (author) 5 figs., 13 refs.

  12. Reflect: a practical approach to web semantics

    DEFF Research Database (Denmark)

    O'Donoghue, S.I.; Horn, Heiko; Pafilisa, E.

    2010-01-01

    To date, adding semantic capabilities to web content usually requires considerable server-side re-engineering, thus only a tiny fraction of all web content currently has semantic annotations. Recently, we announced Reflect (http://reflect.ws), a free service that takes a more practical approach......: Reflect uses augmented browsing to allow end-users to add systematic semantic annotations to any web-page in real-time, typically within seconds. In this paper we describe the tagging process in detail and show how further entity types can be added to Reflect; we also describe how publishers and content...... web technologies....

  13. Reflection amplifiers in self-regulated learning

    NARCIS (Netherlands)

    Verpoorten, Dominique

    2012-01-01

    Verpoorten, D. (2012). Reflection amplifiers in self-regulated learning. Doctoral thesis. November, 9, 2012, Heerlen, The Netherlands: Open Universiteit (CELSTEC). Datawyse / Universitaire Pers Maastricht.

  14. Room-temperature near-field reflection spectrocopy of semiconductor nanostructures

    DEFF Research Database (Denmark)

    Langbein, Wolfgang; Hvam, Jørn Märcher; Madsen, Steen

    1999-01-01

    We investigate the properties of near-field reflection spectroscopy in different polarization and detection modes using uncoated fiber probes. The results show, that cross-polarized detection suppresses to a large extent far-field contributions. Using the fiber dithering as a modulation source fo...

  15. An asymptotic model of seismic reflection from a permeable layer

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.; Goloshubin, G.

    2009-10-15

    Analysis of compression wave propagation in a poroelastic medium predicts a peak of reflection from a high-permeability layer in the low-frequency end of the spectrum. An explicit formula expresses the resonant frequency through the elastic moduli of the solid skeleton, the permeability of the reservoir rock, the fluid viscosity and compressibility, and the reservoir thickness. This result is obtained through a low-frequency asymptotic analysis of Biot's model of poroelasticity. A review of the derivation of the main equations from the Hooke's law, momentum and mass balance equations, and Darcy's law suggests an alternative new physical interpretation of some coefficients of the classical poroelasticity. The velocity of wave propagation, the attenuation factor, and the wave number, are expressed in the form of power series with respect to a small dimensionless parameter. The absolute value of this parameter is equal to the product of the kinematic reservoir fluid mobility and the wave frequency. Retaining only the leading terms of the series leads to explicit and relatively simple expressions for the reflection and transmission coefficients for a planar wave crossing an interface between two permeable media, as well as wave reflection from a thin highly-permeable layer (a lens). Practical applications of the obtained asymptotic formulae are seismic modeling, inversion, and at-tribute analysis.

  16. A climatology of visible surface reflectance spectra

    International Nuclear Information System (INIS)

    Zoogman, Peter; Liu, Xiong; Chance, Kelly; Sun, Qingsong; Schaaf, Crystal; Mahr, Tobias; Wagner, Thomas

    2016-01-01

    We present a high spectral resolution climatology of visible surface reflectance as a function of wavelength for use in satellite measurements of ozone and other atmospheric species. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is planned to measure backscattered solar radiation in the 290–740 nm range, including the ultraviolet and visible Chappuis ozone bands. Observation in the weak Chappuis band takes advantage of the relative transparency of the atmosphere in the visible to achieve sensitivity to near-surface ozone. However, due to the weakness of the ozone absorption features this measurement is more sensitive to errors in visible surface reflectance, which is highly variable. We utilize reflectance measurements of individual plant, man-made, and other surface types to calculate the primary modes of variability of visible surface reflectance at a high spectral resolution, comparable to that of TEMPO (0.6 nm). Using the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirection Reflectance Distribution Function (BRDF)/albedo product and our derived primary modes we construct a high spatial resolution climatology of wavelength-dependent surface reflectance over all viewing scenes and geometries. The Global Ozone Monitoring Experiment–2 (GOME-2) Lambertian Equivalent Reflectance (LER) product provides complementary information over water and snow scenes. Preliminary results using this approach in multispectral ultraviolet+visible ozone retrievals from the GOME-2 instrument show significant improvement to the fitting residuals over vegetated scenes. - Highlights: • Our goals was visible surface reflectance for satellite trace gas measurements. • Captured the range of surface reflectance spectra through EOF analysis. • Used satellite surface reflectance products for each given scene to anchor EOFs. • Generated a climatology of time/geometry dependent surface reflectance spectra. • Demonstrated potential to

  17. Multifractal Cross Wavelet Analysis

    Science.gov (United States)

    Jiang, Zhi-Qiang; Gao, Xing-Lu; Zhou, Wei-Xing; Stanley, H. Eugene

    Complex systems are composed of mutually interacting components and the output values of these components usually exhibit long-range cross-correlations. Using wavelet analysis, we propose a method of characterizing the joint multifractal nature of these long-range cross correlations, a method we call multifractal cross wavelet analysis (MFXWT). We assess the performance of the MFXWT method by performing extensive numerical experiments on the dual binomial measures with multifractal cross correlations and the bivariate fractional Brownian motions (bFBMs) with monofractal cross correlations. For binomial multifractal measures, we find the empirical joint multifractality of MFXWT to be in approximate agreement with the theoretical formula. For bFBMs, MFXWT may provide spurious multifractality because of the wide spanning range of the multifractal spectrum. We also apply the MFXWT method to stock market indices, and in pairs of index returns and volatilities we find an intriguing joint multifractal behavior. The tests on surrogate series also reveal that the cross correlation behavior, particularly the cross correlation with zero lag, is the main origin of cross multifractality.

  18. Evaluated cross section libraries

    International Nuclear Information System (INIS)

    Maqurno, B.A.

    1976-01-01

    The dosimetry tape (ENDF/B-IV tape 412) was issued in a general CSEWG distribution, August 1974. The pointwise cross section data file was tested with specified reference spectra. A group averaged cross section data file (620 groups based on tape 412) was tested with the above spectra and the results are presented in this report

  19. Jet inclusive cross sections

    International Nuclear Information System (INIS)

    Del Duca, V.

    1992-11-01

    Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons

  20. "Keeping SCORE": Reflective Practice through Classroom Observations

    Science.gov (United States)

    Farrell, Thomas S. C.

    2011-01-01

    Reflective practice means that teachers must subject their own teaching beliefs and practices to critical examination. One way of facilitating reflective practice in ESL teachers is to encourage them to engage in classroom observations as part of their professional development. This paper reports on a case study of a short series of classroom…

  1. Reflections on Teaching Financial Statement Analysis

    Science.gov (United States)

    Entwistle, Gary

    2015-01-01

    In her 2011 article "Towards a 'scholarship of teaching and learning': The individual and the communal journey," Ursula Lucas calls for more critical reflection on individual teaching experiences and encourages sharing such experiences with the wider academy. In this spirit Gary Entwistle reflects upon his experiences teaching financial…

  2. Mid infrared upconversion spectroscopy using diffuse reflectance

    DEFF Research Database (Denmark)

    Sanders, Nicolai Højer; Kehlet, Louis M.; Dam, Jeppe Seidelin

    2014-01-01

    specifically that upconversion methods can be deployed using a diffuse reflectance setup where the test sample is irradiated by a thermal light source, i.e. a globar. The diffuse reflectance geometry is particularly well suited when a transmission setup cannot be used. This situation may happen for highly...

  3. Talking Online: Reflecting on Online Communication Tools

    Science.gov (United States)

    Greener, Susan

    2009-01-01

    Purpose: The purpose of this paper is to reflect on the value and constraints of varied online communication tools from web 2.0 to e-mail in a higher education (HE) teaching and learning context, where these tools are used to support or be the main focus of learning. Design/methodology/approach: A structured reflection is produced with the aid of…

  4. Teacher Reflective Practice in Jesuit High Schools

    Science.gov (United States)

    Klug, Joseph H.

    2010-01-01

    Teachers who engage in reflective practice are more effective and may encourage higher student achievement. The purpose of this study is to explore and describe the methods that teachers use in order to engage in reflective practice. Further, it is essential to gain an understanding of how schools, including Jesuit high schools, promote reflective…

  5. Reflections of a Latino Associate Professor

    Science.gov (United States)

    Peguero, Anthony A.

    2018-01-01

    The following reflection essay is about my experiences as a Latino Associate Professor who focuses on criminology, youth violence, juvenile justice, and the associated disparities with race, ethnicity, and immigration. I reflect about the "race and justice" job market, pursuing and establishing a Latina/o Criminology working group, often…

  6. Exploring Reflective Means to Handle Plagiarism

    Science.gov (United States)

    Dalal, Nikunj

    2016-01-01

    Plagiarism has become widespread in the university teaching environment. This article presents practical wisdom from several years of experience handling plagiarism in two Information Systems (IS) courses with the exploratory use of reflective means such as dialogues and essays. There has been very little work on the use of reflective approaches…

  7. The strong reflecting property and Harrington's Principle

    OpenAIRE

    Cheng, Yong

    2015-01-01

    In this paper we characterize the strong reflecting property for $L$-cardinals for all $\\omega_n$, characterize Harrington's Principle $HP(L)$ and its generalization and discuss the relationship between the strong reflecting property for $L$-cardinals and Harrington's Principle $HP(L)$.

  8. Timing the total reflection of light

    International Nuclear Information System (INIS)

    Chauvat, Dominique; Bonnet, Christophe; Dunseath, Kevin; Emile, Olivier; Le Floch, Albert

    2005-01-01

    We have identified for the first time the absolute delay at total reflection, envisioned by Newton. We show that there are in fact two divergent Wigner delays, depending on the polarisation of the incident light. These measurements give a new insight on the passage from total reflection to refraction

  9. Reflection in Medical Diagnosis: A Literature Review

    Directory of Open Access Journals (Sweden)

    Silvia Mamede

    2017-06-01

    Discussion: Reflective reasoning can be a powerful tool to reduce diagnostic errors and increase diagnostic performance. For this to happen, reflection should be triggered for diagnosis verification and needs to interfere with initial diagnostic reasoning, which requires confrontation with evidence from the case.

  10. "Dear Diary" Revisited: Reflecting on Collaborative Journaling

    Science.gov (United States)

    Mackenzie, Catrina A.; Ricker, Britta; Christensen, Julia; Heller, Elizabeth; Kagan, Emily; Osano, Philip M.; Long, Lindsay; Turner, Sarah

    2013-01-01

    The genesis of this article was a request from the "Journal of Geography in Higher Education" to provide a reflection piece about our article 'Dear Diary: Early Career Geographers Collectively Reflect on their Qualitative Field Research Experiences' (2011) that won the journal's biennial award for 2009-2011. This request has afforded us…

  11. How Reflective Is the Academic Essay?

    Science.gov (United States)

    Maclellan, Effie

    2004-01-01

    The purpose of this study was to examine the extent of reflection in academic essays. Forty essays, all previously deemed to be of merit quality, were analysed in terms of three elements of reflection--how the educational issue is conceptualized; what the issue means for practice; and how practice might be changed to resolve the problematic. Each…

  12. História da enfermagem psiquiátrica e a dependência química no Brasil: atravessando a história para reflexão Historia de la enfermería psiquiátrica y la dependencia química en el Brasil: atravesando la historia para la reflexión History of the psychiatric nursing and chemical dependency in Brazil: crossing the history for reflection

    Directory of Open Access Journals (Sweden)

    Amanda Márcia dos Santos Reinaldo

    2007-12-01

    ón del enfermero profesional. Ambas temáticas encuentran puntos de aproximación y alejamiento conforme el contexto en que son analizadas.The nursing education in psychiatric nursing and in the area of chemical dependency guides the discussion of this article towards the complexity of problems related to the nursing, mental health, psychiatric and alcohol and drugs teaching. It is a literature review where the authors compiled primary and secondary sources on the theme. Analyses and reflections on historical crossings that permeate the history of the psychiatric nursing and chemical dependency in Brazil were performed on the bibliographic material. The results point to an evolution of the theme alcohol and drugs given the magnitude of the problem in the contemporaneous society. Regarding the psychiatric nursing, the teaching presents changes due to the historical evolution of the psychiatry that must be considered during the education of the nursing professional. Both themes had common and distinctive points according to the context in which they were analyzed.

  13. American Red Cross Headquarters

    Data.gov (United States)

    Department of Homeland Security — This point file represents only the headquarters location for each chapter and does not reflect any branch offices or warehouse facilities. Due to the recent changes...

  14. Crossing a Nonlinear Resonance

    Indian Academy of Sciences (India)

    IAS Admin

    Fermi's theory for the acceleration of cosmic rays [2] as- sumes that the ... The most well-known example goes back to the Lorentz–. Einstein .... inside and reflecting from the boundary according to ..... Here the chaotic layers of different.

  15. Global Explorers Journaling and Reflection Initiative

    Directory of Open Access Journals (Sweden)

    John Bennion

    2016-12-01

    Full Text Available Research suggests that journaling will increase reflection and improve program outcomes (Bain, et al, 1999; Duerden, et al, 2012 This study involved a partnership with a non-profit, Global Explorers (GEx, which provides international immersion experiences for youth. Their programs are designed to teach youth participants principles of leadership, environmental awareness, service, and science. This study, which tested whether teaching journaling techniques to youth program facilitators would have a positive impact on participant outcomes, addressed the following hypotheses: 1 Greater training in reflective thinking among participants would be associated with higher outcome scores, and 2 Participants in the intervention group (facilitators trained in journaling pedagogy would show greater increases in reflective thinking than comparison group members. Results based on participant self-assessment were significant in testing the first hypothesis; reflective thinking is positively associated with outcome measures, but the intervention group did not show increases in reflective thinking.

  16. Particle reflection and TFTR neutral beam diagnostics

    International Nuclear Information System (INIS)

    Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O'Connor, T.E.; Newman, R.A.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

    1992-04-01

    Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12 degrees). Beamline calorimeters, of a ''V''-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the ''V'', complicating the fitting technique, and increasing the power density on axis by 10 to 20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected

  17. Fracture diagnostics with tube wave reflection logs

    International Nuclear Information System (INIS)

    Medlin, W.L.

    1991-01-01

    This paper reports on the Tube Wave Reflection Log (TWRL) which is acoustic logging method which provides information about the height, location and conductivity of hydraulically induced fractures behind perforated casing. The TWRL tool consists of a transmitter and closely spaced receiver. The transmitter is driven with a short, low frequency tone burst to generate long wavelength tube waves which are little attenuated in unperforated casing. They are partially reflected when they pass perforated intervals communicating with a hydraulically induced fracture. The tool listens for such reflections for 0.1 seconds following each excitation burst. As the tool is moved uphole at logging speed, the transmitter is excited at each foot of depth. VDL displays of the TWRL records provide reflection traces whose projections define the uppermost and lower-most perforations communicating with the fracture. The strength of the reflections depends on the ease of fluid flow into the fracture and thus, is an indicator of fracture conductivity

  18. Ultraviolet reflectance by the cere of raptors

    Science.gov (United States)

    Mougeot, François; Arroyo, Beatriz E

    2006-01-01

    Ultraviolet (UV) signals have been shown to play key roles in social and sexual signalling in birds. Using a spectrophotometer, we analysed the colour of the cere (skin above the beak) of a diurnal raptor, the Montagu's harrier (Circus pygargus), and show that it reflects in the UV part of the spectrum. The cere is a well-known sexual signal in raptors, with carotenoid based pigmentation being indicative of quality. We thus hypothesized that UV reflectance also signals quality. Accordingly, we found that in our sample of wild males, the location of the UV peak was related to the orangeness of cere and correlated with male body mass and condition (mass corrected for size). Also, males with brighter UV were mated to females that laid earlier, as expected if UV reflectance relates to a male's quality and attractiveness. Future studies should investigate the relationships between UV reflectance and carotenoid pigmentation of cere, and test how UV reflectance influences mate choice. PMID:17148356

  19. Sutherland models for complex reflection groups

    International Nuclear Information System (INIS)

    Crampe, N.; Young, C.A.S.

    2008-01-01

    There are known to be integrable Sutherland models associated to every real root system, or, which is almost equivalent, to every real reflection group. Real reflection groups are special cases of complex reflection groups. In this paper we associate certain integrable Sutherland models to the classical family of complex reflection groups. Internal degrees of freedom are introduced, defining dynamical spin chains, and the freezing limit taken to obtain static chains of Haldane-Shastry type. By considering the relation of these models to the usual BC N case, we are led to systems with both real and complex reflection groups as symmetries. We demonstrate their integrability by means of new Dunkl operators, associated to wreath products of dihedral groups

  20. Transparency of atom-sized superconducting junctions

    International Nuclear Information System (INIS)

    Van-der-Post, N.; Peters, E.T.; Van Ruitenbeek, J.M.; Yanson, I.K.

    1995-01-01

    We discuss the transparency of atom-size superconducting tunnel junctions by comparing experimental values of the normal resistance and Subgap Structure with the theoretical predictions for these phenomena by Landauer's formula and Multiple Andreev Reflection, respectively

  1. Reflection seismic studies in the Forsmark area - stage 1

    Energy Technology Data Exchange (ETDEWEB)

    Juhlin, Christopher; Bergman Bjoern; Palm, Hans [Uppsala Univ. (Sweden). Dept. of Earth Sciences

    2002-10-01

    Reflection seismic data were acquired in the Spring of 2002 in the Forsmark area, located about 70 km northeast of Uppsala, Sweden. The Forsmark area has been targeted by SKB as a possible storage site for high level radioactive waste. About 16 km of high resolution seismic data were acquired along five separate profiles varying in length from 2 to 5 km. Non-final source and receiver spacing was 10 m with 100 active channels when recording data from a dynamite source (15-75 g). The profiles were located within a relatively undeformed lens of bedrock that trends in the NW-SE direction. The lens is surrounded by highly deformed rock on all sides. In conjunction with the reflection component of the study, all shots were also recorded on up to eleven 3-component fixed Orion seismographs. These recordings provided long offset data from which a velocity model of the uppermost 400 m of bedrock could be derived. Results from the study show that the bedrock has been well imaged down to depths of at least 3 km. The upper 1000 m of bedrock is much more reflective in the southeastern portion of the lens compared to the northwestern part close to the Forsmark reactors. This is interpreted as the bedrock being more homogeneous in the northwest. However, a major reflective zone (the A1 reflector) is interpreted to dip to the S-SE below this homogeneous bedrock. In the southeastern portion of the lens the orientation of the reflectors is well determined where the profiles cross one another. The general strike of the major reflectors is NE-SW with dips of 20-35 degrees to the southeast.

  2. Born reflection kernel analysis and wave-equation reflection traveltime inversion in elastic media

    KAUST Repository

    Wang, Tengfei; Cheng, Jiubing

    2017-01-01

    Elastic reflection waveform inversion (ERWI) utilize the reflections to update the low and intermediate wavenumbers in the deeper part of model. However, ERWI suffers from the cycle-skipping problem due to the objective function of waveform residual

  3. Reflecting on reflection in interprofessional education: implications for theory and practice.

    Science.gov (United States)

    Clark, Phillip G

    2009-05-01

    Interprofessional education (IPE) involves learning, and learning requires reflection. Educators need to "reflect more on reflection" if they are to be effective teachers in ensuring the learning outcomes essential for teamwork and interprofessional practice (IPP), including incorporating both theory and practice into the development of educational interventions. First, this discussion surveys the IPE-relevant literature on reflection, and then defines and refines the multidimensional concept of reflection as it relates to IPE in developing and implementing teamwork learning programs and experiences. Second, specific methods to promote reflection are presented and explored, including self-assessments, journaling, and written papers. Actual samples from student journals and assignments provide examples of the impacts of using these methods on participant reflection and learning. Finally, implications for an expanded understanding and application of reflection for IPE will be discussed, and recommendations made for educational practice and research in this area.

  4. Site investigation SFR. Reprocessing of reflection seismic profiles 5b and 8, Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Juhlin, Christopher; Zhang, Fengjiao (Uppsala Univ., Dept. of Earth Sciences (Sweden))

    2010-12-15

    Reflection seismic profiles 5b and 8 in the northern Forsmark area have been reprocessed with the aim of improving the images in the uppermost 500 metres in the SFR area. The main conclusion is that a new reflection (B10) has been identified that may extend below the SFR site. This reflection was not clearly observed in the previous processing. The reflection strikes approximately N25E and dips at about 35 degrees to the southeast. This orientation is similar to the set B group identified earlier /Juhlin and Palm 2005/. Note that the dip of the reflection is uncertain. On shot gathers it appears to dip at a slightly shallower angle while on the stacked sections it appears to dip at a greater angle. This discrepancy is probably due to the crooked nature of the profiles. However, reflections are clearly observed in shot gathers and its presence below SFR is highly probable. Two new reflections were also identified further north along profile 5b (A11 and A12). These dip to the south-southeast, but would be found at a depth of 1-2 km below SFR if they extend to below the site. There are also signs of a 3rd reflection with similar orientation to the set A group identified earlier, A13, but its existence is very speculative. This reflector would intersect the surface within the SFR area. South of the Singoe deformation zone on profile 5b, another new reflection has been found, N1. The orientation of this reflection is speculative since it is not clearly seen on profile 8. It has been modelled as dipping to the north at about 35 degrees and projects to the surface south of the main SFR area. In addition, the orientation of reflection B7 has been revised as has the lateral extent of A1. Most importantly, A1 is now interpreted not to extend to the surface and not cross the Singoe deformation zone

  5. Analysis of Grazing GNSS Reflections Observed at the Zeppelin Mountain Station, Spitsbergen

    Science.gov (United States)

    Peraza, L.; Semmling, M.; Falck, C.; Pavlova, O.; Gerland, S.; Wickert, J.

    2017-11-01

    A reflectometry station has been set up in 2013 near Ny-Ålesund, Svalbard, at 78.9082°N, 11.9031°E. The main goal of the setup is to resolve the spatial and temporal variations in snow and ice cover, based on reflection power observations at grazing elevations. In this study, we develop a method to map the recorded signal power to the main reflection contributions while also discussing the spatial characteristics of the observations. A spectral analysis resolving differential Doppler between direct and reflected signals is presented to identify reflection contributions for a complete year (2014). Strong water reflections are identified with power ratios higher than 70 dB/Hz and constant Doppler shifts of 0.5-0.6 Hz for all elevations. Contributions with ratios higher than 40 dB/Hz can be related to specular land or glacier reflections, for which Doppler shift usually increases with the elevation angle and the distance between reflection point and receiver. Reflections nearby, around 3-5 km, show differential Doppler of 0.4-0.5 Hz, while for reflections farther than 16 km away, Doppler shift is usually larger than 0.8 Hz. Azimuth variations cause cross-track drift of up to 4° during the observation year. Topography-induced shadowing of very low lying satellites limits the extent of the monitoring area. However, the amount of satellites tracked daily, up to 30, allows the reflectometry station to constantly record reflections over areas with thick snow cover and glaciers. This offers the possibility to compare the derived reflected power with local meteorological data to resolve snow and ice variations on the area.

  6. A technique for the radar cross-section estimation of axisymmetric plasmoid

    International Nuclear Information System (INIS)

    Naumov, N D; Petrovskiy, V P; Sasinovskiy, Yu K; Shkatov, O Yu

    2015-01-01

    A model for the radio waves backscattering from both penetrable plasma and reflecting plasma is developed. The technique proposed is based on Huygens's principle and reduces the radar cross-section estimation to numerical integrations. (paper)

  7. Obtaining local reflectivity at two-way travel time by filtering acoustic reflection data

    NARCIS (Netherlands)

    Slob, E.C.; Zhang, L.; Wapenaar, C.P.A.; Mihai Popovici, A.; Fomel, S.

    2017-01-01

    A modified implementation of Marchenko redatuming leads to a filter that removes internal multiples from reflection data. It produces local reflectivity at two-way travel time. The method creates new primary reflections resulting from emitted events that eliminate internal multiples. We call these

  8. Reflective Practice for Psychology Students: The Use of Reflective Journal Feedback in Higher Education

    Science.gov (United States)

    Bruno, Andreina; Dell'Aversana, Giuseppina

    2017-01-01

    Reflective journals have emerged as an effective means of monitoring and developing reflective practice in higher education, as part of a wider metacognitive strategy to transform traditional learning approaches. In addition, assessment procedures of reflective journals appear to be an important factor in enhancing commitment to learning and…

  9. Library search with regular reflectance IR spectra

    International Nuclear Information System (INIS)

    Staat, H.; Korte, E.H.; Lampen, P.

    1989-01-01

    Characterisation in situ for coatings and other surface layers is generally favourable, but a prerequisite for precious items such as art objects. In infrared spectroscopy only reflection techniques are applicable here. However for attenuated total reflection (ATR) it is difficult to obtain the necessary optical contact of the crystal with the sample, when the latter is not perfectly plane or flexible. The measurement of diffuse reflectance demands a scattering sample and usually the reflectance is very poor. Therefore in most cases one is left with regular reflectance. Such spectra consist of dispersion-like feature instead of bands impeding their interpretation in the way the analyst is used to. Furthermore for computer search in common spectral libraries compiled from transmittance or absorbance spectra a transformation of the reflectance spectra is needed. The correct conversion is based on the Kramers-Kronig transformation. This somewhat time - consuming procedure can be speeded up by using appropriate approximations. A coarser conversion may be obtained from the first derivative of the reflectance spectrum which resembles the second derivative of a transmittance spectrum. The resulting distorted spectra can still be used successfully for the search in peak table libraries. Experiences with both transformations are presented. (author)

  10. Assessing reflective thinking and approaches to learning.

    Science.gov (United States)

    Dunn, Louise; Musolino, Gina M

    2011-01-01

    Facilitation of reflective practice is critical for the ongoing demands of health care practitioners. Reflective thinking concepts, grounded in the work of Dewey and Schön, emphasize critical reflection to promote transformation in beliefs and learning necessary for reflective practice. The Reflective Thinking Questionnaire (QRT) and Revised Study Process Questionnaire (RSPQ-2F) assess skill aspects of professional reasoning, with promise for measuring changes over time. The purpose of this study was to examine the reliability and responsiveness and the model validity of reflective thinking and approaches to learning measures for U.S. health professions students enrolled in entry-level occupational (MOT) and physical therapy (DPT) programs. This measurement study addressed reliability and responsiveness of two measures, the QRT and RSPQ-2F, for graduate health professionals. A convenience sample of 125 MOT and DPT students participated in the two-measure, test-retest investigation, with electronic data collection. Outcomes support the stability of the four-scale QRT (ICC 0.63 to 0.82) and the two-scale RSPQ-2F (ICC 0.91 and 0.87). Descriptive data supporting responsiveness are presented. With noted limitations, the results support the use of the QRT and RSPQ-2F measures to assess changes in reflective thinking and approaches to learning. Measurement of these learning outcomes furthers our understanding and knowledge about instructional strategies, development of professional reasoning, and fostering of self-directed learning within MOT and DPT programs.

  11. Total internal reflection effect on gyrotropic interface

    Science.gov (United States)

    Glushchenko, Alexander G.; Glushchenko, Eugene P.; Zhukov, Sergey V.

    2018-02-01

    This article considers the physical features of total internal reflection at gyrotropic and isotropic interfaces for two cases: electrical gyrotropy (plasma) and magnetic gyrotropy (ferrite). It is shown that the plasma magnetization may lead to the formation of the total internal reflection effect, which does not occur in isotropic plasma. The threshold values of the magnetic field, which are necessary for the total internal reflection effect, are determined. The total internal reflection effect on a ferrite-dielectric interface for waves emanating from different angles is observed in various frequency ranges and magnetization fields. The study points out the possibility of changing the total internal reflection angle value in large limits due to a change in the external magnetic field magnitude. The calculation results of the total internal reflection angle dependence on the external magnetic field magnitude are presented. The formulas are elaborated for calculating the total internal reflection angles of different interfaces for gyrotropic and isotropic media. The generalized formulas are defined for calculating the Doppler effect in the gyrotropic media. The study demonstrates how the velocity of the media interface affects the limiting angle of total internal refection.

  12. Preparation of next generation set of group cross sections. 3

    International Nuclear Information System (INIS)

    Kaneko, Kunio

    2002-03-01

    This fiscal year, based on the examination result about the evaluation energy range of heavy element unresolved resonance cross sections, the upper energy limit of the energy range, where ultra-fine group cross sections are produced, was raised to 50 keV, and an improvement of the group cross section processing system was promoted. At the same time, reflecting the result of studies carried out till now, a function producing delayed neutron data was added to the general-purpose group cross section processing system , thus the preparation of general purpose group cross section processing system has been completed. On the other hand, the energy structure, data constitution and data contents of next generation group cross section set were determined, and the specification of a 151 groups next generation group cross section set was defined. Based on the above specification, a concrete library format of the next generation cross section set has been determined. After having carried out the above-described work, using the general-purpose group cross section processing system , which was complete in this study, with use of the JENDL-3. 2 evaluated nuclear data, the 151 groups next generation group cross section of 92 nuclides and the ultra fine group resonance cross section library for 29 nuclides have been prepared. Utilizing the 151 groups next generation group cross section set and the ultra-fine group resonance cross-section library, a bench mark test calculation of fast reactors has been performed by using an advanced lattice calculation code. It was confirmed, by comparing the calculation result with a calculation result of continuous energy Monte Carlo code, that the 151 groups next generation cross section set has sufficient accuracy. (author)

  13. Non-invasive detection of murals with pulsed terahertz reflected imaging system

    Science.gov (United States)

    Yuan, Minjie; Sun, Wenfeng; Wang, Xinke; Ye, Jiasheng; Wang, Sen; Zhang, Qunxi; Zhang, Yan

    2015-11-01

    Pulsed terahertz reflected imaging technology has been expected to have great potential for the non-invasive analysis of artworks. In this paper, three types of defects hidden in the plaster used to simulate the cases of defects in the murals, have been investigated by a pulsed terahertz reflected imaging system. These preset defects include a circular groove, a cross-shaped slit and a piece of "Y-type" metal plate built in the plaster. With the terahertz reflective tomography, information about defects has been determined involving the thickness from the surface of sample to the built-in defect, the profile and distribution of the defect. Additionally, three-dimensional analyses have been performed in order to reveal the internal structure of defects. Terahertz reflective imaging can be applied to the defect investigation of the murals.

  14. MMS Observation of Shock-Reflected He++ at Earth's Quasi-Perpendicular Bow Shock

    Science.gov (United States)

    Broll, Jeffrey Michael; Fuselier, S. A.; Trattner, K. J.; Schwartz, S. J.; Burch, J. L.; Giles, B. L.; Anderson, B. J.

    2018-01-01

    Specular reflection of protons at Earth's supercritical quasi-perpendicular bow shock has long been known to lead to the thermalization of solar wind particles by velocity-space dispersion. The same process has been proposed for He++ but could not be confirmed previously due to insufficient time resolution for velocity distribution measurements. We present observations and simulations of a bow shock crossing by the Magnetospheric Multiscale (MMS) mission on 20 November 2015 indicating that a very similar reflection process for He++ is possible, and further that the part of the incoming distribution with the highest probability of reflecting is the same for H+ and He++. However, the reflection process for He++ is accomplished by deeper penetration into the downstream magnetic fields.

  15. Stealth metamaterial objects characterized in the far field by Radar Cross Section measurements

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Fan, K.; Strikwerda, A. C.

    Reflection spectra and radar cross sections (RCS) at terahertz frequencies are measured on structures incorporating absorbing metamaterials. Reduction of the RCS by the factor of 375 at the resonant frequencies is observed.......Reflection spectra and radar cross sections (RCS) at terahertz frequencies are measured on structures incorporating absorbing metamaterials. Reduction of the RCS by the factor of 375 at the resonant frequencies is observed....

  16. Glue Film Thickness Measurements by Spectral Reflectance

    International Nuclear Information System (INIS)

    Marshall, B.R.

    2010-01-01

    Spectral reflectance was used to determine the thickness of thin glue layers in a study of the effect of the glue on radiance and reflectance measurements of shocked-tin substrates attached to lithium fluoride windows. Measurements based on profilometry of the components were found to be inaccurate due to flatness variations and deformation of the tin substrate under pressure during the gluing process. The accuracy of the spectral reflectance measurements were estimated to be ±0.5 (micro)m, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  17. Personal Professional Reflection as Interdisciplinary Problem

    Directory of Open Access Journals (Sweden)

    Rezvan Oksana

    2013-08-01

    Full Text Available Consideration of professional reflection as interdisciplinary problem is the necessary condition of quality analysis for personal professional becoming. Personal becoming in a profession is related to forming the necessary professional skills of a person, behaviour stereotypes which is the area of pedagogics. Reflection processes are inalienable part of self-knowledge of a person which result must lead to his self-perfection (including professional one and studying within the psychology increasingly. Thus the aim of the article is to ground the determination of professional reflection as an interdisciplinary problem in pedagogics and psychology.

  18. Glue Film Thickness Measurements by Spectral Reflectance

    Energy Technology Data Exchange (ETDEWEB)

    B. R. Marshall

    2010-09-20

    Spectral reflectance was used to determine the thickness of thin glue layers in a study of the effect of the glue on radiance and reflectance measurements of shocked-tin substrates attached to lithium fluoride windows. Measurements based on profilometry of the components were found to be inaccurate due to flatness variations and deformation of the tin substrate under pressure during the gluing process. The accuracy of the spectral reflectance measurements were estimated to be ±0.5 μm, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  19. Researching critical reflection in management education

    DEFF Research Database (Denmark)

    Elkjaer, Bente; Nickelsen, Niels Christian Mossfeldt

    2016-01-01

    Critical reflection for professionals involves the ability to learn directly from their practice experience, so that they can improve their own work in an ongoing and flexible way. By examining the fundamental bases of what they do systematically, critical reflection can also function as a form...... to deal with change and critical reflection provides one method for being able to incorporate changes in a way which allows individuals to preserve a sense of what is fundamentally important to them as professionals. Since many different professionals work together in most organisations, research...... of education, management, health and social work....

  20. Moral Reasoning among Nigerian Northern Irish Children: A Cross ...

    African Journals Online (AJOL)

    The moral reasoning of 10-11 year old Nigerian children (n=37) was compared to children of the same age (n=48) from Northern Ireland. The research employed the Socio moral Reflection Measure-Short Form (SRM-SF; Gibbs, Basinger & Fuller, 1992) and assessed the measure's usefulness for cross-cultural research.

  1. Cross Country MetroLink Segment I Business Plan

    Science.gov (United States)

    1997-12-02

    In the St. Louis, Missouri metropolitan area, the East-West Gateway Coordinating : Council decided the route for the first MetroLink extension in the Cross-County : Corridor in September 1997. The next phase, reflected in this paper is develop, : dur...

  2. Cross-cultural School Based Encounters as Health Education

    DEFF Research Database (Denmark)

    Bruselius-Jensen, Maria; Renwick, Kerry; Aagaard-Hansen, Jens

    2017-01-01

    : Qualitative analysis of 18 focus group discussions with 72 Danish and 36 Kenyan students. Results: Cross-cultural dialogues promoted students’ engagement and reflections on their own and peers’ health condition, access to education, food cultures, gender and family structures. Conclusion: Findings indicate...

  3. A geometric derivation of the dyon wall-crossing group

    NARCIS (Netherlands)

    Cheng, M.C.N.; Hollands, L.

    2009-01-01

    Recently, using supergravity analysis, a hyperbolic reflection group was found to underlie the structure of wall-crossing, or the discontinuous moduli dependence of the supersymmetric index due to the presence of walls of marginal stability, of the BPS dyons in the N = 4, d = 4 compactification. In

  4. Crossing simple resonances

    International Nuclear Information System (INIS)

    Collins, T.

    1985-08-01

    A simple criterion governs the beam distortion and/or loss of protons on a fast resonance crossing. Results from numerical integrations are illustrated for simple sextupole, octupole, and 10-pole resonances

  5. Cross-impact method

    Directory of Open Access Journals (Sweden)

    Suzić Nenad

    2014-01-01

    Full Text Available The paper displays the application of the Cross-Impact method in pedagogy, namely a methodological approach which crosses variables in a novel, but statistically justified manner. The method is an innovation in pedagogy as well as in research methodology of social and psychological phenomena. Specifically, events and processes are crossed, that is, experts' predictions of about future interaction of events and processes. Therefore, this methodology is futuristic; it concerns predicting future, which is of key importance for pedagogic objectives. The paper presents two instances of the cross-impact approach: the longer, displayed in fourteen steps, and the shorter, in four steps. They are both accompanied with mathematic and statistical formulae allowing for quantification, that is, a numerical expression of the probability of a certain event happening in the future. The advantage of this approach is that it facilitates planning in education which so far has been solely based on lay estimates and assumptions.

  6. Cross-Platform Technologies

    Directory of Open Access Journals (Sweden)

    Maria Cristina ENACHE

    2017-04-01

    Full Text Available Cross-platform - a concept becoming increasingly used in recent years especially in the development of mobile apps, but this consistently over time and in the development of conventional desktop applications. The notion of cross-platform software (multi-platform or platform-independent refers to a software application that can run on more than one operating system or computing architecture. Thus, a cross-platform application can operate independent of software or hardware platform on which it is execute. As a generic definition presents a wide range of meanings for purposes of this paper we individualize this definition as follows: we will reduce the horizon of meaning and we use functionally following definition: a cross-platform application is a software application that can run on more than one operating system (desktop or mobile identical or in a similar way.

  7. Floodplain Cross Section Lines

    Data.gov (United States)

    Department of Homeland Security — This table is required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally any FIRM...

  8. Multitrajectory eikonal cross sections

    International Nuclear Information System (INIS)

    Turner, R.E.

    1983-01-01

    With the use of reference and distorted transition operators, a time-correlation-function representation of the inelastic differential cross section has recently been used to obtain distorted eikonal cross sections. These cross sections involve straight-line and reference classical translational trajectories that are unaffected by any internal-state changes which have occurred during the collision. This distorted eikonal theory is now extended to include effects of internal-state changes on the translational motion. In particular, a different classical trajectory is associated with each pair of internal states. Expressions for these inelastic cross sections are obtained in terms of time-ordered cosine and sine memory functions using the Zwanzig-Feshbach projection-operator method. Explicit formulas are obtained in the time-disordered perturbation approximation

  9. HARP MHI- Cross Seamount

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — PIFSC and Scripps Institution of Oceanography (SIO) conducted passive acoustic monitoring for cetaceans at Cross Seamount in 2005 and 2006 using a High-Frequency...

  10. Crossing simple resonances

    Energy Technology Data Exchange (ETDEWEB)

    Collins, T.

    1985-08-01

    A simple criterion governs the beam distortion and/or loss of protons on a fast resonance crossing. Results from numerical integrations are illustrated for simple sextupole, octupole, and 10-pole resonances.

  11. Cross validation in LULOO

    DEFF Research Database (Denmark)

    Sørensen, Paul Haase; Nørgård, Peter Magnus; Hansen, Lars Kai

    1996-01-01

    The leave-one-out cross-validation scheme for generalization assessment of neural network models is computationally expensive due to replicated training sessions. Linear unlearning of examples has recently been suggested as an approach to approximative cross-validation. Here we briefly review...... the linear unlearning scheme, dubbed LULOO, and we illustrate it on a systemidentification example. Further, we address the possibility of extracting confidence information (error bars) from the LULOO ensemble....

  12. Metoda Criss-Cross

    OpenAIRE

    Papež, Jan

    2008-01-01

    This thesis describes the criss-cross method, which solves the tasks of linear programming and does not need primar or dual feasibility of the basis. At first, the single-phase simplex method, that needs primal feasibility, gets described. After that, we describe the dual simplex method, which needs dual feasibility. The criss-cross method combines both of these methods. All of mentioned methods are explained and demonstrated in several examples.

  13. Peer group reflection helps clinical teachers to critically reflect on their teaching.

    Science.gov (United States)

    Boerboom, Tobias B B; Jaarsma, Debbie; Dolmans, Diana H J M; Scherpbier, Albert J J A; Mastenbroek, Nicole J J M; Van Beukelen, Peter

    2011-01-01

    Student evaluations can help clinical teachers to reflect on their teaching skills and find ways to improve their teaching. Studies have shown that the mere presentation of student evaluations is not a sufficient incentive for teachers to critically reflect on their teaching. We evaluated and compared the effectiveness of two feedback facilitation strategies that were identical except for a peer reflection meeting. In this study, 54 clinical teachers were randomly assigned to two feedback strategies. In one strategy, a peer reflection was added as an additional step. All teachers completed a questionnaire evaluating the strategy that they had experienced. We analysed the reflection reports and the evaluation questionnaire. Both strategies stimulated teachers to reflect on feedback and formulate alternative actions for their teaching practice. The teachers who had participated in the peer reflection meeting showed deeper critical reflection and more concrete plans to change their teaching. All feedback strategies were considered effective by the majority of the teachers. Strategies with student feedback and self-assessment stimulated reflection on teaching and helped clinical teachers to formulate plans for improvement. A peer reflection meeting seemed to enhance reflection quality. Further research should establish whether it can have lasting effects on teaching quality.

  14. Supporting Teacher Reflection through Online Discussion

    Directory of Open Access Journals (Sweden)

    Jiening Ruan

    2011-12-01

    Full Text Available The purpose of this case study was to investigate online discussion as a means to promote critical reflection. The study was conducted during a semester-long graduate course on issues related to literacy instructional strategies. The participants in the study were four reading education candidates. During the semester they participated in online discussion about course readings and reflected on their own teaching experiences. The data sources were the online discussion postings, responses to questionnaires, and interviews. The results suggest that technology-mediated discussion strengthens the learning community, facilitates sharing of professional experience among participants, and enhances teacher reflection. The results also point to the multi-faceted nature of teacher reflection.

  15. Spectral reflectance relationships to leaf water stress

    Science.gov (United States)

    Ripple, William J.

    1986-01-01

    Spectral reflectance data were collected from detached snapbean leaves in the laboratory with a multiband radiometer. Four experiments were designed to study the spectral response resulting from changes in leaf cover, relative water content of leaves, and leaf water potential. Spectral regions included in the analysis were red (630-690 nm), NIR (760-900 nm), and mid-IR (2.08-2.35 microns). The red and mid-IR bands showed sensitivity to changes in both leaf cover and relative water content of leaves. The NIR was only highly sensitive to changes in leaf cover. Results provided evidence that mid-IR reflectance was governed primarily by leaf moisture content, although soil reflectance was an important factor when leaf cover was less than 100 percent. High correlations between leaf water potentials and reflectance were attributed to covariances with relative water content of leaves and leaf cover.

  16. Lamont Doherty Seismic Reflection Scanned Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains single channel seismic reflection profiles as provided to NGDC by Lamont Doherty Earh Observatory (LDEO). The profiles were originally...

  17. Reflective Self-Regenerative Systems Architecture Study

    National Research Council Canada - National Science Library

    Pu, Carlton; Blough, Douglas

    2006-01-01

    In this study, we develop the Reflective Self-Regenerative Systems (RSRS) architecture in detail, describing the internal structure of each component and the mutual invocations among the components...

  18. Force Reflection Algorithms for Exoskeleton Controllers

    National Research Council Canada - National Science Library

    Bryfogle, Mark

    1991-01-01

    This research effort investigated the kinematics and dynamics of open chain, serial linkage mechanisms with specific emphasis placed upon the application of this linkage as a force reflecting exoskeleton mechanism...

  19. Telerobotic Control Architecture Including Force-Reflection

    National Research Council Canada - National Science Library

    Murphy, Mark

    1998-01-01

    This report describes the implementation of a telerobotic control architecture to manipulate a standard six-degree-of-freedom robot via a unique seven-degree-of-freedom force-reflecting exoskeleton...

  20. Automatic specular reflections removal for endoscopic images

    Science.gov (United States)

    Tan, Ke; Wang, Bin; Gao, Yuan

    2017-07-01

    Endoscopy imaging is utilized to provide a realistic view about the surfaces of organs inside the human body. Owing to the damp internal environment, these surfaces usually have a glossy appearance showing specular reflections. For many computer vision algorithms, the highlights created by specular reflections may become a significant source of error. In this paper, we present a novel method for restoration of the specular reflection regions from a single image. Specular restoration process starts with generating a substitute specular-free image with RPCA method. Then the specular removed image was obtained by taking the binary weighting template of highlight regions as the weighting for merging the original specular image and the substitute image. The modified template was furthermore discussed for the concealment of artificial effects in the edge of specular regions. Experimental results on the removal of the endoscopic image with specular reflections demonstrate the efficiency of the proposed method comparing to the existing methods.

  1. Four-Mirror Freeform Reflective Imaging Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — Central Objectives: The research involves a revelation of the solution space for revolutionary families of four-mirror freeform reflective imaging systems. A...

  2. Elastic reflection waveform inversion with variable density

    KAUST Repository

    Li, Yuanyuan; Li, Zhenchun; Alkhalifah, Tariq Ali; Guo, Qiang

    2017-01-01

    Elastic full waveform inversion (FWI) provides a better description of the subsurface than those given by the acoustic assumption. However it suffers from a more serious cycle skipping problem compared with the latter. Reflection waveform inversion

  3. Reflective self-awareness and conscious states

    DEFF Research Database (Denmark)

    Kjaer, Troels W; Nowak, Markus; Lou, Hans C

    2002-01-01

    A recent meta-analysis has shown precuneus, angular gyri, anterior cingulate gyri, and adjacent structures to be highly metabolically active in support of resting consciousness. We hypothesize that these regions constitute a functional network of reflective self-awareness thought to be a core...... function of consciousness. Seven normal volunteers were asked to think intensely on how they would describe the personality traits and physical appearance of themselves and a neutral reference person known to all the subjects (the Danish Queen). During each of the four conditions cerebral blood flow...... during reflective self-awareness. The commonality between the neural networks of the resting conscious state and self-awareness reflects the phenomenological concept of a fundamental contribution of reflective self-awareness to the contents and coherence of the conscious state....

  4. Developing teachers through research: reflections on method

    African Journals Online (AJOL)

    Erna Kinsey

    was decided upon as the best means of reflecting teachers' under- standing of ... Through the use of language (communication) people critically under- stand a ... strategies and assessment exercises without looking at them as part of a whole ...

  5. Reflection Negative Kernels and Fractional Brownian Motion

    Directory of Open Access Journals (Sweden)

    Palle E. T. Jorgensen

    2018-06-01

    Full Text Available In this article we study the connection of fractional Brownian motion, representation theory and reflection positivity in quantum physics. We introduce and study reflection positivity for affine isometric actions of a Lie group on a Hilbert space E and show in particular that fractional Brownian motion for Hurst index 0 < H ≤ 1 / 2 is reflection positive and leads via reflection positivity to an infinite dimensional Hilbert space if 0 < H < 1 / 2 . We also study projective invariance of fractional Brownian motion and relate this to the complementary series representations of GL 2 ( R . We relate this to a measure preserving action on a Gaussian L 2 -Hilbert space L 2 ( E .

  6. Monolithically integrated 8-channel WDM reflective modulator

    NARCIS (Netherlands)

    Stopinski, S.T.; Malinowski, M.; Piramidowicz, R.; Smit, M.K.; Leijtens, X.J.M.

    2013-01-01

    In this work the design and characterization of a monolithically integrated photonic circuit acting as a reflective modulator for eight WDM channels is presented. The chip was designed and fabricated in a generic integration technology

  7. Salinity and spectral reflectance of soils

    Science.gov (United States)

    Szilagyi, A.; Baumgardner, M. F.

    1991-01-01

    The basic spectral response related to the salt content of soils in the visible and reflective IR wavelengths is analyzed in order to explore remote sensing applications for monitoring processes of the earth system. The bidirectional reflectance factor (BRF) was determined at 10 nm of increments over the 520-2320-nm spectral range. The effect of salts on reflectance was analyzed on the basis of 162 spectral measurements. MSS and TM bands were simulated within the measured spectral region. A strong relationship was found in variations of reflectance and soil characteristics pertaining to salinization and desalinization. Although the individual MSS bands had high R-squared values and 75-79 percent of soil/treatment combinations were separable, there was a large number of soil/treatment combinations not distinguished by any of the four highly correlated MSS bands under consideration.

  8. "Comparatography", History and Policy Quotation: Some Reflections

    Science.gov (United States)

    Phillips, David

    2014-01-01

    This paper revisits the question of the importance of a historical dimension in comparative inquiry and reflects on some problems in what is termed "comparatography", the writing of comparative education.

  9. Specular Reflection of Sunlight from Earth

    Science.gov (United States)

    Varnai, T.; Marshak, A.

    2018-02-01

    The Deep Space Gateway vantage point offers advantages in observing specular reflection from water surfaces or ice crystals in clouds. Such data can give information on clouds and atmospheric aerosols, and help test algorithms of future exoplanet characterization.

  10. Listening as Translation: Reflections on Professional Development Work in a Cross-Cultural Setting

    Science.gov (United States)

    Schultz, Katherine; Smulyan, Lisa

    2007-01-01

    As part of a campus-wide response by the University of Pennsylvania to the large-scale disaster caused by the earthquake and tsunami in South Asia, a team of teacher educators and graduate students worked with teachers, teacher educators, and administrators in Banda Aceh, Indonesia during July of 2005 and 2006. Working in Indonesia highlighted for…

  11. (Irrationalism: At the cross-roads of historical and systematic reflection

    Directory of Open Access Journals (Sweden)

    Danie F.M. Strauss

    2013-07-01

    Full Text Available This article is dedicated to Ponti Venter for his contribution to the historical roots and systematic implications of philosophical problems. A discussion with him about four decades ago prompted me to investigate the Greek roots of our distinction of thought and being. In the analysis below, a brief sketch was given of the initial identification of thought and being in the thought of Parmenides and the consequences it had for the rationalistic tradition since the Renaissance, particularly in connection with the view that the universe itself has a rational structure. Two options were pursued in our analysis of rationalism: (1 to contrast it with empiricism and (2 to relate it to universality and the problem of what is individual. By distinguishing between conceptual and concept-transcending knowledge, an alternative systematic characterisation of rationalism (and irrationalism is proposed, namely that it absolutises conceptual knowledge (whilst irrationalism deifies concepttranscending knowledge. This view allows for an acknowledgement of the ontic horizon of human experience, co-constituted by the dimensions of modal aspects and type laws, without elevating human understanding to become the law-giver of the world.

  12. Small ones and big ones: cross-taxon congruence reflects organism body size in ombrotrophic bogs

    Czech Academy of Sciences Publication Activity Database

    Hájek, Michal; Poulíčková, A.; Vašutová, Martina; Syrovátka, V.; Jiroušek, M.; Štěpánková, J.; Opravilová, V.; Hájková, Petra

    2014-01-01

    Roč. 726, č. 1 (2014), s. 95-107 ISSN 0018-8158 R&D Projects: GA ČR GA206/08/0389 Institutional support: RVO:67985939 ; RVO:67179843 Keywords : biomonitoring * multi-proxy * species richness Subject RIV: EF - Botanics; EH - Ecology, Behaviour (UEK-B) Impact factor: 2.275, year: 2014

  13. Global sourcing - performance and integration : reflections on performance, implications from cross-functional and external integration

    NARCIS (Netherlands)

    Horn, Philipp

    2013-01-01

    Despite the fact that firms and individuals have been sourcing on a global basis since ancient times, global sourcing as a topic has received considerable attention from managers and scholars in recent years. Global business has been reported to be growing considerably during the last decades and

  14. Social technologies : Cross-disciplinary reflections on technologies in and from the social sciences Introduction

    NARCIS (Netherlands)

    Derksen, Maarten; Vikkelso, Signe; Beaulieu, Anne

    In this introduction, we explore the relevance to critical psychology of the ideas about technology that have come from science and technology studies (STS), which we argue allow a new look at a classic theme in critical approaches in psychology. Rather than seeing psychical and social reality as

  15. Crossing Borders by "Walking Around" Culture: Ethnographic Reflections on Teacher Preparation

    Science.gov (United States)

    Sparapani, Ervin F.; Seo, Byung-In; Smith, Deborah L.

    2012-01-01

    The United Nations Educational, Scientific, and Cultural Organization (UNESCO) documents that the world has become increasingly multicultural and multilingual as international migration rates grow each year. The cultural and language diversity in the United States exemplifies this worldwide phenomenon. It is the authors' belief that teachers have…

  16. Reflective and Transformative Practice in Bilingual Teacher Preparation: Examining Cross-Cultural and Linguistic Equity

    Science.gov (United States)

    Hernández, Ana M.

    2017-01-01

    Culture, class, and language are significant social markers that impact classrooms today with challenges in educating teachers to become culturally responsive and competent. This article presents a theoretical approach on the preparation of bilingual teacher candidates and how the literature can inform teacher education programs on developing…

  17. Crossing Borders by "Walking around" Culture: Three Ethnographic Reflections on Teacher Preparation

    Science.gov (United States)

    Sparapani, Ervin F.; Seo, Byung-In; Smith, Deborah L.

    2011-01-01

    The United States of the twenty-first century is possibly the most culturally/racially diverse country of any nation in history, and families that are culturally/racially different from mainstream society do not always see that schools are meeting the needs of their children. This diversity in culture and language means that each person is…

  18. High {Tc} superconductivity: Symmetries and reflections

    International Nuclear Information System (INIS)

    Zhang, S.C.

    1999-01-01

    This is a talk given at the Symposium Symmetries and Reflections, dedicated to Prof. C.N. Yang's retirement. In this talk, the author reflects on his personal interaction with Prof. Yang since his graduate career at SUNY Stony Brook, and his profound impact on his understanding of theoretical physics. He also reviews the SO(5) theory of high T c superconductivity and shows how his collaboration with Prof. Yang in 1990 lead to the foundation of this idea

  19. Light reflection models for computer graphics.

    Science.gov (United States)

    Greenberg, D P

    1989-04-14

    During the past 20 years, computer graphic techniques for simulating the reflection of light have progressed so that today images of photorealistic quality can be produced. Early algorithms considered direct lighting only, but global illumination phenomena with indirect lighting, surface interreflections, and shadows can now be modeled with ray tracing, radiosity, and Monte Carlo simulations. This article describes the historical development of computer graphic algorithms for light reflection and pictorially illustrates what will be commonly available in the near future.

  20. Simulation Tool for GNSS Ocean Surface Reflections

    DEFF Research Database (Denmark)

    Høeg, Per; von Benzon, Hans-Henrik; Durgonics, Tibor

    2015-01-01

    GNSS coherent and incoherent reflected signals have the potential of deriving large scale parameters of ocean surfaces, as barotropic variability, eddy currents and fronts, Rossby waves, coastal upwelling, mean ocean surfaceheights, and patterns of the general ocean circulation. In the reflection...... zone the measurements may deriveparameters as sea surface roughness, winds, waves, heights and tilts from the spectral measurements. Previous measurements from the top of mountains and airplanes have shown such results leading.The coming satellite missions, CYGNSS, COSMIC-2, and GEROS...

  1. Identifying diffraction effects in measured reflectances

    OpenAIRE

    Holzschuch , Nicolas; Pacanowski , Romain

    2015-01-01

    International audience; There are two different physical models connecting the micro-geometry of a surface and its physical reflectance properties (BRDF). The first, Cook-Torrance, assumes geometrical optics: light is reflected and masked by the micro-facets. In this model, the BRDF depends on the probability distribution of micro-facets normals. The second, Church-Takacs, assumes diffraction by the micro-geometry. In this model, the BRDF depends on the power spectral distribution of the surf...

  2. Associations between teaching effectiveness and participant self-reflection in continuing medical education.

    Science.gov (United States)

    Ratelle, John T; Bonnes, Sara L; Wang, Amy T; Mahapatra, Saswati; Schleck, Cathy D; Mandrekar, Jayawant N; Mauck, Karen F; Beckman, Thomas J; Wittich, Christopher M

    2017-07-01

    Effective medical educators can engage learners through self-reflection. However, little is known about the relationships between teaching effectiveness and self-reflection in continuing medical education (CME). We aimed to determine associations between presenter teaching effectiveness and participant self-reflection in conference-based CME. This cross-sectional study evaluated presenters and participants at a national CME course. Participants provided CME teaching effectiveness (CMETE) ratings and self-reflection scores for each presentation. Overall CMETE and CME self-reflection scores (five-point Likert scale with one as strongly disagree and five as strongly agree) were averaged for each presentation. Correlations were measured among self-reflection, CMETE, and presentation characteristics. In total, 624 participants returned 430 evaluations (response, 68.9%) for the 38 presentations. Correlation between CMETE and self-reflection was medium (Pearson correlation, 0.3-0.5) or large (0.5-1.0) for most presentations (n = 33, 86.9%). Higher mean (SD) CME reflection scores were associated with clinical cases (3.66 [0.12] vs. 3.48 [0.14]; p = 0.003) and audience response (3.66 [0.12] vs. 3.51 [0.14]; p = 0.005). To our knowledge, this is the first study to show a relationship between teaching effectiveness and participant self-reflection in conference-based CME. Presenters should consider using clinical cases and audience response systems to increase teaching effectiveness and promote self-reflection among CME learners.

  3. Cross-talk in abscisic acid signaling

    Science.gov (United States)

    Fedoroff, Nina V.

    2002-01-01

    "Cross-talk" in hormone signaling reflects an organism's ability to integrate different inputs and respond appropriately, a crucial function at the heart of signaling network operation. Abscisic acid (ABA) is a plant hormone involved in bud and seed dormancy, growth regulation, leaf senescence and abscission, stomatal opening, and a variety of plant stress responses. This review summarizes what is known about ABA signaling in the control of stomatal opening and seed dormancy and provides an overview of emerging knowledge about connections between ABA, ethylene, sugar, and auxin synthesis and signaling.

  4. Cross-border reproductive care : market forces in action or market failure? An economic perspective

    NARCIS (Netherlands)

    Connolly, Mark

    2011-01-01

    From an economist's perspective, cross-border reproductive care (CBRC) reflects a global market economy bringing together the needs of patients and skills of doctors at an agreed price. From this perspective CBRC is neither wrong nor right, rather it reflects rational economic behaviour of couples

  5. Optical Reflectance Measurements for Commonly Used Reflectors

    Science.gov (United States)

    Janecek, Martin; Moses, William W.

    2008-08-01

    When simulating light collection in scintillators, modeling the angular distribution of optical light reflectance from surfaces is very important. Since light reflectance is poorly understood, either purely specular or purely diffuse reflectance is generally assumed. In this paper we measure the optical reflectance distribution for eleven commonly used reflectors. A 440 nm, output power stabilized, un-polarized laser is shone onto a reflector at a fixed angle of incidence. The reflected light's angular distribution is measured by an array of silicon photodiodes. The photodiodes are movable to cover 2pi of solid angle. The light-induced current is, through a multiplexer, read out with a digital multimeter. A LabVIEW program controls the motion of the laser and the photodiode array, the multiplexer, and the data collection. The laser can be positioned at any angle with a position accuracy of 10 arc minutes. Each photodiode subtends 6.3deg, and the photodiode array can be positioned at any angle with up to 10 arc minute angular resolution. The dynamic range for the current measurements is 10 5:1. The measured light reflectance distribution was measured to be specular for several ESR films as well as for aluminum foil, mostly diffuse for polytetrafluoroethylene (PTFE) tape and titanium dioxide paint, and neither specular nor diffuse for Lumirrorreg, Melinexreg and Tyvekreg. Instead, a more complicated light distribution was measured for these three materials.

  6. Reflective and refractive objects for mixed reality.

    Science.gov (United States)

    Knecht, Martin; Traxler, Christoph; Winklhofer, Christoph; Wimmer, Michael

    2013-04-01

    In this paper, we present a novel rendering method which integrates reflective or refractive objects into a differential instant radiosity (DIR) framework usable for mixed-reality (MR) applications. This kind of objects are very special from the light interaction point of view, as they reflect and refract incident rays. Therefore they may cause high-frequency lighting effects known as caustics. Using instant-radiosity (IR) methods to approximate these high-frequency lighting effects would require a large amount of virtual point lights (VPLs) and is therefore not desirable due to real-time constraints. Instead, our approach combines differential instant radiosity with three other methods. One method handles more accurate reflections compared to simple cubemaps by using impostors. Another method is able to calculate two refractions in real-time, and the third method uses small quads to create caustic effects. Our proposed method replaces parts in light paths that belong to reflective or refractive objects using these three methods and thus tightly integrates into DIR. In contrast to previous methods which introduce reflective or refractive objects into MR scenarios, our method produces caustics that also emit additional indirect light. The method runs at real-time frame rates, and the results show that reflective and refractive objects with caustics improve the overall impression for MR scenarios.

  7. Reflective masks for extreme ultraviolet lithography

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Khanh Bao [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    Extreme ultraviolet lithographic masks are made by patterning multilayer reflective coatings with high normal incidence reflectivity. Masks can be patterned by depositing a patterned absorber layer above the coating or by etching the pattern directly into the coating itself. Electromagnetic simulations showed that absorber-overlayer masks have superior imaging characteristics over etched masks (less sensitive to incident angles and pattern profiles). In an EUVL absorber overlayer mask, defects can occur in the mask substrate, reflective coating, and absorber pattern. Electromagnetic simulations showed that substrate defects cause the most severe image degradation. A printability study of substrate defects for absorber overlayer masks showed that printability of 25 nm high substrate defects are comparable to defects in optical lithography. Simulations also indicated that the manner in which the defects are covered by multilayer reflective coatings can affect printability. Coverage profiles that result in large lateral spreading of defect geometries amplify the printability of the defects by increasing their effective sizes. Coverage profiles of Mo/Si coatings deposited above defects were studied by atomic force microscopy and TEM. Results showed that lateral spread of defect geometry is proportional to height. Undercut at defect also increases the lateral spread. Reductions in defect heights were observed for 0.15 μm wide defect lines. A long-term study of Mo/Si coating reflectivity revealed that Mo/Si coatings with Mo as the top layer suffer significant reductions in reflectivity over time due to oxidation.

  8. Properties of interstellar dust in reflection nebulae

    International Nuclear Information System (INIS)

    Sellgren, K.

    1988-01-01

    Observations of interstellar dust in reflection nebulae are the closest analog in the interstellar medium to studies of cometary dust in our solar system. The presence of a bright star near the reflection nebula dust provides the opportunity to study both the reflection and emission characteristics of interstellar dust. At 0.1 to 1 micrometer, the reflection nebula emission is due to starlight scattered by dust. The albedo and scattering phase function of the dust is determined from observations of the scattered light. At 50 to 200 micrometers, thermal emission from the dust in equilibrium with the stellar radiation field is observed. The derived dust temperature determines the relative values of the absorption coefficient of the dust at wavelengths where the stellar energy is absorbed and at far infrared wavelengths where the absorbed energy is reradiated. These emission mechanisms directly relate to those seen in the near and mid infrared spectra of comets. In a reflection nebula the dust is observed at much larger distances from the star than in our solar system, so that the equilibrium dust temperature is 50 K rather than 300 K. Thus, in reflection nebulae, thermal emission from dust is emitted at 50 to 200 micrometer

  9. Photoionization of Endohedral Atoms: Collective, Reflective and Collateral Emissions

    International Nuclear Information System (INIS)

    Chakraborty, Himadri S.; McCune, Matthew A.; Hopper, Dale E.; Madjet, Mohamed E.; Manson, Steven T.

    2009-01-01

    The photoionization properties of a fullerene-confined atom differ dramatically from that of an isolated atom. In the low energy region, where the fullerene plasmons are active, the electrons of the confined atom emerge through a collective channel carrying a significant chunk of plasmon with it. The photoelectron angular distribution of the confined atom however shows far lesser impact of the effect. At higher energies, the interference between two single-electron ionization channels, one directly from the atom and another reflected off the fullerene cage, producuces oscillatory cross sections. But for the outermost atomic level, which transfers some electrons to the cage, oscillations are further modulated by the collateral emission from the part of the atomic charge density transferred to the cage. These various modes of emissions are studied for the photoionization of Ar endohedrally confined in C 60 .

  10. Fecal corticosterone reflects serum corticosterone in Florida sandhill cranes.

    Science.gov (United States)

    Ludders, J W; Langenberg, J A; Czekala, N M; Erb, H N

    2001-07-01

    Florida sandhill cranes (Grus canadensis pratensis) were conditioned to confinement 6 hr/day for 7 days. On day 8, each bird's jugular vein was catheterized, blood samples were drawn, and each crane was confined for 6 hr. Using a randomized, restricted cross-over design, cranes were injected intravenously with either 0.9% NaCl solution or ACTH (cosyntropin; Cortrosyn; 0.25 mg). During the 6 hr of confinement, fecal samples (feces and urine) were collected from each of five cranes immediately after defecation. Individual fecal samples were collected approximately at hourly intervals and assayed for corticosterone. We showed previously that serum corticosterone did not vary significantly following saline injection, but peaked significantly 60 min after ACTH injection. Maximal fecal corticosterone concentrations (ng/g) were greater (P cranes under controlled conditions, fecal corticosterone concentration reflects serum corticosterone levels, fecal corticosterone, Grus canadensis pratensis, sandhill cranes, serum corticosterone levels.

  11. Students' reflections on shadowing interprofessional teamwork: a Norwegian case study.

    Science.gov (United States)

    Fougner, M; Horntvedt, T

    2011-01-01

    This article reports the students' reflections on interprofessional teamwork during brief exposures to real-life experiences in hospitals or home-based rehabilitation service. Each of the 10 interprofessional groups, comprising three students, followed a rehabilitation team for a day. The composition of each student group correlated with the rehabilitation team. Data were collected from interviews with the student groups and subjected to a thematic analysis. The following four main themes were identified for which the students seemed to affect collaboration: sharing knowledge; team setting and position within the organisation; patient centred focus; and challenges in crossing professional borders when performing tasks. Each of these themes is presented and discussed in relation to the educational literature. In conclusion, the data suggest that a well organized, one-day observation-based learning experience helped to motivate students and helped to enable them to relate theory and practice.

  12. Characterizing the reflectivity of handheld display devices.

    Science.gov (United States)

    Liu, Peter; Badano, Aldo

    2014-08-01

    With increased use of handheld and tablet display devices for viewing medical images, methods for consistently measuring reflectivity of the devices are needed. In this note, the authors report on the characterization of diffuse reflections for handheld display devices including mobile phones and tablets using methods recommended by the American Association of Physicists in Medicine Task Group 18 (TG18). The authors modified the diffuse reflectance coefficient measurement method outlined in the TG18 report. The authors measured seven handheld display devices (two phones and five tablets) and three workstation displays. The device was attached to a black panel with Velcro. To study the effect of the back surface on the diffuse reflectance coefficient, the authors created Styrofoam masks with different size square openings and placed it in front of the device. Overall, for each display device, measurements of illuminance and reflected luminance on the display screen were taken. The authors measured with no mask, with masks of varying size, and with display-size masks, and calculated the corresponding diffuse reflectance coefficient. For all handhelds, the diffuse reflectance coefficient measured with no back panel were lower than measurements performed with a mask. The authors found an overall increase in reflectivity as the size of the mask decreases. For workstations displays, diffuse reflectance coefficients were higher when no back panel was used, and higher than with masks. In all cases, as luminance increased, illuminance increased, but not at the same rate. Since the size of handheld displays is smaller than that of workstation devices, the TG18 method suffers from a dependency on illumination condition. The authors show that the diffuse reflection coefficients can vary depending on the nature of the back surface of the illuminating box. The variability in the diffuse coefficient can be as large as 20% depending on the size of the mask. For all measurements

  13. Reflectance, illumination, and appearance in color constancy.

    Science.gov (United States)

    McCann, John J; Parraman, Carinna; Rizzi, Alessandro

    2014-01-01

    We studied color constancy using a pair of identical 3-D Color Mondrian displays. We viewed one 3-D Mondrian in nearly uniform illumination, and the other in directional, nonuniform illumination. We used the three dimensional structures to modulate the light falling on the painted surfaces. The 3-D structures in the displays were a matching set of wooden blocks. Across Mondrian displays, each corresponding facet had the same paint on its surface. We used only 6 chromatic, and 5 achromatic paints applied to 104 block facets. The 3-D blocks add shadows and multiple reflections not found in flat Mondrians. Both 3-D Mondrians were viewed simultaneously, side-by-side. We used two techniques to measure correlation of appearance with surface reflectance. First, observers made magnitude estimates of changes in the appearances of identical reflectances. Second, an author painted a watercolor of the 3-D Mondrians. The watercolor's reflectances quantified the changes in appearances. While constancy generalizations about illumination and reflectance hold for flat Mondrians, they do not for 3-D Mondrians. A constant paint does not exhibit perfect color constancy, but rather shows significant shifts in lightness, hue and chroma in response to the structure in the nonuniform illumination. Color appearance depends on the spatial information in both the illumination and the reflectances of objects. The spatial information of the quanta catch from the array of retinal receptors generates sensations that have variable correlation with surface reflectance. Models of appearance in humans need to calculate the departures from perfect constancy measured here. This article provides a dataset of measurements of color appearances for computational models of sensation.

  14. Reflectance, illumination, and appearance in color constancy

    Directory of Open Access Journals (Sweden)

    John J. McCann

    2014-01-01

    Full Text Available We studied color constancy using a pair of identical 3-D Color Mondrian displays. We viewed one 3-D Mondrian in nearly uniform illumination, and the other in directional, nonuniform illumination. We used the three dimensional structures to modulate the light falling on the painted surfaces. The 3-D structures in the displays were a matching set of wooden blocks. Across Mondrian displays, each corresponding facet had the same paint on its surface. We used only 6 chromatic, and 5 achromatic paints applied to 104 block facets. The 3-D blocks add shadows and multiple reflections not found in flat Mondrians. Both 3-D Mondrians were viewed simultaneously, side-by-side. We used two techniques to measure correlation of appearance with surface reflectance. First, observers made magnitude estimates of changes in the appearances of identical reflectances. Second, an author painted a watercolor of the 3-D Mondrians. The watercolor’s reflectances quantified the changes in appearances. While constancy generalizations about illumination and reflectance hold for flat Mondrians, they do not for 3-D Mondrians. A constant paint does not exhibit perfect color constancy, but rather shows significant shifts in lightness, hue and chroma in response to the structure in the nonuniform illumination. Color appearance depends on the spatial information in both the illumination and the reflectances of objects. The spatial information of the quanta catch from the array of retinal receptors generates sensations that have variable correlation with surface reflectance. Models of appearance in humans need to calculate the departures from perfect constancy measured here. This article provides a dataset of measurements of color appearances for computational models of sensation.

  15. Neural activity associated with self-reflection.

    Science.gov (United States)

    Herwig, Uwe; Kaffenberger, Tina; Schell, Caroline; Jäncke, Lutz; Brühl, Annette B

    2012-05-24

    Self-referential cognitions are important for self-monitoring and self-regulation. Previous studies have addressed the neural correlates of self-referential processes in response to or related to external stimuli. We here investigated brain activity associated with a short, exclusively mental process of self-reflection in the absence of external stimuli or behavioural requirements. Healthy subjects reflected either on themselves, a personally known or an unknown person during functional magnetic resonance imaging (fMRI). The reflection period was initialized by a cue and followed by photographs of the respective persons (perception of pictures of oneself or the other person). Self-reflection, compared with reflecting on the other persons and to a major part also compared with perceiving photographs of one-self, was associated with more prominent dorsomedial and lateral prefrontal, insular, anterior and posterior cingulate activations. Whereas some of these areas showed activity in the "other"-conditions as well, self-selective characteristics were revealed in right dorsolateral prefrontal and posterior cingulate cortex for self-reflection; in anterior cingulate cortex for self-perception and in the left inferior parietal lobe for self-reflection and -perception. Altogether, cingulate, medial and lateral prefrontal, insular and inferior parietal regions show relevance for self-related cognitions, with in part self-specificity in terms of comparison with the known-, unknown- and perception-conditions. Notably, the results are obtained here without behavioural response supporting the reliability of this methodological approach of applying a solely mental intervention. We suggest considering the reported structures when investigating psychopathologically affected self-related processing.

  16. Self-reflection Orients Visual Attention Downward.

    Science.gov (United States)

    Liu, Yi; Tong, Yu; Li, Hong

    2017-01-01

    Previous research has demonstrated abstract concepts associated with spatial location (e.g., God in the Heavens) could direct visual attention upward or downward, because thinking about the abstract concepts activates the corresponding vertical perceptual symbols. For self-concept, there are similar metaphors (e.g., "I am above others"). However, whether thinking about the self can induce visual attention orientation is still unknown. Therefore, the current study tested whether self-reflection can direct visual attention. Individuals often display the tendency of self-enhancement in social comparison, which reminds the individual of the higher position one possesses relative to others within the social environment. As the individual is the agent of the attention orientation, and high status tends to make an individual look down upon others to obtain a sense of pride, it was hypothesized that thinking about the self would lead to a downward attention orientation. Using reflection of personality traits and a target discrimination task, Study 1 found that, after self-reflection, visual attention was directed downward. Similar effects were also found after friend-reflection, with the level of downward attention being correlated with the likability rating scores of the friend. Thus, in Study 2, a disliked other was used as a control and the positive self-view was measured with above-average judgment task. We found downward attention orientation after self-reflection, but not after reflection upon the disliked other. Moreover, the attentional bias after self-reflection was correlated with above-average self-view. The current findings provide the first evidence that thinking about the self could direct visual-spatial attention downward, and suggest that this effect is probably derived from a positive self-view within the social context.

  17. Adjustable wideband reflective converter based on cut-wire metasurface

    International Nuclear Information System (INIS)

    Zhang, Linbo; Zhou, Peiheng; Chen, Haiyan; Lu, Haipeng; Xie, Jianliang; Deng, Longjiang

    2015-01-01

    We present the design, analysis, and measurement of a broadband reflective converter using a cut-wire (CW) metasurface. Based on the characteristics of LC resonances, the proposed reflective converter can rotate a linearly polarized (LP) wave into its cross-polarized wave at three resonance frequencies, or convert the LP wave to a circularly polarized (CP) wave at two other resonance frequencies. Furthermore, the broad-band properties of the polarization conversion can be sustained when the incident wave is a CP wave. The polarization states can be adjusted easily by changing the length and width of the CW. The measured results show that a polarization conversion ratio (PCR) over 85% can be achieved from 6.16 GHz to 16.56 GHz for both LP and CP incident waves. The origin of the polarization conversion is interpreted by the theory of microwave antennas, with equivalent impedance and electromagnetic (EM) field distributions. With its simple geometry and multiple broad frequency bands, the proposed converter has potential applications in the area of selective polarization control. (paper)

  18. Flexible manipulation of terahertz wave reflection using polarization insensitive coding metasurfaces.

    Science.gov (United States)

    Jiu-Sheng, Li; Ze-Jiang, Zhao; Jian-Quan, Yao

    2017-11-27

    In order to extend to 3-bit encoding, we propose notched-wheel structures as polarization insensitive coding metasurfaces to control terahertz wave reflection and suppress backward scattering. By using a coding sequence of "00110011…" along x-axis direction and 16 × 16 random coding sequence, we investigate the polarization insensitive properties of the coding metasurfaces. By designing the coding sequences of the basic coding elements, the terahertz wave reflection can be flexibly manipulated. Additionally, radar cross section (RCS) reduction in the backward direction is less than -10dB in a wide band. The present approach can offer application for novel terahertz manipulation devices.

  19. Modelling binaural processes involved in simultaneous reflection masking: limitations of current models

    DEFF Research Database (Denmark)

    Buchholz, Jörg

    2007-01-01

    Masked thresholds were measured for a single test reflection, masked by the direct sound, as a function of the reflection delay. This was done for diotic as well as for dichotic stimulus presentations and all stimuli were presented via headphones. The input signal was a 200-ms long broadband noise......, such as normalized cross-correlation models (e.g., Bernstein et al., 1999, JASA, pp. 870-876), the power-addition model (Zurek, 1979, JASA, pp. 1750-1757), or Equalization-Cancellation-based models (e.g., Breebaart et al., 2001, JASA, pp. 1074-1088), cannot account for the psychoacoustical data. The present talk...

  20. Polarization resolved imaging with a reflection near-field optical microscope

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Xiao, Mufei; Hvam, Jørn Märcher

    1999-01-01

    Using a rigorous microscopic point-dipole description of probe-sample interactions, we study imaging with a reflection scanning near-field optical microscope. Optical content, topographical artifacts, sensitivity window-i.e., the scale on which near-field optical images represent mainly optical...... configuration is preferable to the cross-linear one, since it ensures more isotropic (in the surface plane) near-field imaging of surface features. The numerical results are supported with experimental near-field images obtained by using a reflection microscope with an uncoated fiber tip....

  1. MUXS: a code to generate multigroup cross sections for sputtering calculations

    International Nuclear Information System (INIS)

    Hoffman, T.J.; Robinson, M.T.; Dodds, H.L. Jr.

    1982-10-01

    This report documents MUXS, a computer code to generate multigroup cross sections for charged particle transport problems. Cross sections generated by MUXS can be used in many multigroup transport codes, with minor modifications to these codes, to calculate sputtering yields, reflection coefficients, penetration distances, etc

  2. REFLECTANCE CALIBRATION SCHEME FOR AIRBORNE FRAME CAMERA IMAGES

    Directory of Open Access Journals (Sweden)

    U. Beisl

    2012-07-01

    Full Text Available The image quality of photogrammetric images is influenced by various effects from outside the camera. One effect is the scattered light from the atmosphere that lowers contrast in the images and creates a colour shift towards the blue. Another is the changing illumination during the day which results in changing image brightness within an image block. In addition, there is the so-called bidirectional reflectance of the ground (BRDF effects that is giving rise to a view and sun angle dependent brightness gradient in the image itself. To correct for the first two effects an atmospheric correction with reflectance calibration is chosen. The effects have been corrected successfully for ADS linescan sensor data by using a parametrization of the atmospheric quantities. Following Kaufman et al. the actual atmospheric condition is estimated by the brightness of a dark pixel taken from the image. The BRDF effects are corrected using a semi-empirical modelling of the brightness gradient. Both methods are now extended to frame cameras. Linescan sensors have a viewing geometry that is only dependent from the cross track view zenith angle. The difference for frame cameras now is to include the extra dimension of the view azimuth into the modelling. Since both the atmospheric correction and the BRDF correction require a model inversion with the help of image data, a different image sampling strategy is necessary which includes the azimuth angle dependence. For the atmospheric correction a sixth variable is added to the existing five variables visibility, view zenith angle, sun zenith angle, ground altitude, and flight altitude – thus multiplying the number of modelling input combinations for the offline-inversion. The parametrization has to reflect the view azimuth angle dependence. The BRDF model already contains the view azimuth dependence and is combined with a new sampling strategy.

  3. Improving experimental phases for strong reflections prior to density modification

    International Nuclear Information System (INIS)

    Uervirojnangkoorn, Monarin; Hilgenfeld, Rolf; Terwilliger, Thomas C.; Read, Randy J.

    2013-01-01

    A genetic algorithm has been developed to optimize the phases of the strongest reflections in SIR/SAD data. This is shown to facilitate density modification and model building in several test cases. Experimental phasing of diffraction data from macromolecular crystals involves deriving phase probability distributions. These distributions are often bimodal, making their weighted average, the centroid phase, improbable, so that electron-density maps computed using centroid phases are often non-interpretable. Density modification brings in information about the characteristics of electron density in protein crystals. In successful cases, this allows a choice between the modes in the phase probability distributions, and the maps can cross the borderline between non-interpretable and interpretable. Based on the suggestions by Vekhter [Vekhter (2005 ▶), Acta Cryst. D61, 899–902], the impact of identifying optimized phases for a small number of strong reflections prior to the density-modification process was investigated while using the centroid phase as a starting point for the remaining reflections. A genetic algorithm was developed that optimizes the quality of such phases using the skewness of the density map as a target function. Phases optimized in this way are then used in density modification. In most of the tests, the resulting maps were of higher quality than maps generated from the original centroid phases. In one of the test cases, the new method sufficiently improved a marginal set of experimental SAD phases to enable successful map interpretation. A computer program, SISA, has been developed to apply this method for phase improvement in macromolecular crystallography

  4. A subspecies of region crossing change, region freeze crossing change

    OpenAIRE

    Inoue, Ayumu; Shimizu, Ryo

    2016-01-01

    We introduce a local move on a link diagram named a region freeze crossing change which is close to a region crossing change, but not the same. We study similarity and difference between region crossing change and region freeze crossing change.

  5. Crossed molecular beams

    International Nuclear Information System (INIS)

    Lee, Y.T.

    1976-01-01

    Research activities with crossed molecular beams at Lawrence Berkeley Laboratory during 1976 are described. Topics covered include: scattering of Ar*, Kr*, with Xe; metastable rare gas interactions, He* + H 2 ; an atomic and molecular halogen beam source; a crossed molecular beam study of the Cl + Br 2 → BrCl + Br reaction; O( 3 P) reaction dynamics, development of the high pressure plasma beam source; energy randomization in the Cl + C 2 H 3 Br → Br + C 2 H 3 Cl reaction; high resolution photoionization studies of NO and ICl; photoionization of (H 2 O)/sub n/ and (NH 3 ) 2 ; photoionization mass spectroscopy of NH 3 + and O 3 + ; photo fragmentation of bromine; and construction of chemiluminescence-laser fluorescence crossed molecular beam machine

  6. Existing reflection seismic data re-processing

    International Nuclear Information System (INIS)

    Higashinaka, Motonori; Sano, Yukiko; Kozawa, Takeshi

    2005-08-01

    This document is to report the results of existing seismic data re-processing around Horonobe town, Hokkaido, Japan, which is a part of the Horonobe Underground Research Project. The main purpose of this re-processing is to recognize the subsurface structure of Omagari Fault and fold system around Omagari Fault. The seismic lines for re-processing are TYHR-A3 line and SHRB-2 line, which JAPEX surveyed in 1975. Applying weathering static correction using refraction analysis and noise suppression procedure, we have much enhanced seismic profile. Following information was obtained from seismic re-processing results. TYHR-A3 line: There are strong reflections, dipping to the west. These reflections are corresponding western limb of anticline to the west side of Omagari Fault. SHRB-2 line: There are strong reflections, dipping to the west, at CDP 60-140, while there are reflections, dipping to the east, to the east side of CDP 140. These reflections correspond to the western limb and the eastern limb of the anticline, which is parallel to Omagari FAULT. This seismic re-processing provides some useful information to know the geological structure around Omagari Fault. (author)

  7. Using reflectance spectroscopy to predict beef tenderness.

    Science.gov (United States)

    Bowling, M B; Vote, D J; Belk, K E; Scanga, J A; Tatum, J D; Smith, G C

    2009-05-01

    A study was conducted to determine if reflectance measurements made in the near-infrared region of the spectrum were additive to reflectance measurements made in the visible region of the spectrum for predicting Warner-Bratzler shear force (WBSF) values. Eighty seven strip loins were collected following fabrication over 3d at a commercial beef processing facility from heifer carcasses with Slight or Traces marbling scores. Spectroscopic measurements were made at approximately 50h postmortem using a Hunter-Lab UltraScan. Subsequently, all strip loins were aged for 14d, cooked to an internal temperature of 70°C, and sheared to obtain WBSF values. Reflectance measurements obtained in the near-infrared region of the spectrum were correlated with WBSF values, however, these measurements were not additive to the predictive ability of reflectance measurements (R(2) values did not differ) made in the visible portion of the spectrum when the use of broad-band wavelength filters were simulated. It was therefore determined, that both the visible and near-infrared spectra measure reflectance and that both methods are acceptable methods of tenderness prediction.

  8. Cognitive Reflection Versus Calculation in Decision Making

    Directory of Open Access Journals (Sweden)

    Aleksandr eSinayev

    2015-05-01

    Full Text Available Scores on the three-item Cognitive Reflection Test (CRT have been linked with dual-system theory and normative decision making (Frederick, 2005. In particular, the CRT is thought to measure monitoring of System 1 intuitions such that, if cognitive reflection is high enough, intuitive errors will be detected and the problem will be solved. However, CRT items also require numeric ability to be answered correctly and it is unclear how much numeric ability vs. cognitive reflection contributes to better decision making. In two studies, CRT responses were used to calculate Cognitive Reflection and numeric ability; a numeracy scale was also administered. Numeric ability, measured on the CRT or the numeracy scale, accounted for the CRT’s ability to predict more normative decisions (a subscale of decision-making competence, incentivized measures of impatient and risk-averse choice, and self-reported financial outcomes; Cognitive Reflection contributed no independent predictive power. Results were similar whether the two abilities were modeled (Study 1 or calculated using proportions (Studies 1 and 2. These findings demonstrate numeric ability as a robust predictor of superior decision making across multiple tasks and outcomes. They also indicate that correlations of decision performance with the CRT are insufficient evidence to implicate overriding intuitions in the decision-making biases and outcomes we examined. Numeric ability appears to be the key mechanism instead.

  9. Cognitive reflection vs. calculation in decision making.

    Science.gov (United States)

    Sinayev, Aleksandr; Peters, Ellen

    2015-01-01

    Scores on the three-item Cognitive Reflection Test (CRT) have been linked with dual-system theory and normative decision making (Frederick, 2005). In particular, the CRT is thought to measure monitoring of System 1 intuitions such that, if cognitive reflection is high enough, intuitive errors will be detected and the problem will be solved. However, CRT items also require numeric ability to be answered correctly and it is unclear how much numeric ability vs. cognitive reflection contributes to better decision making. In two studies, CRT responses were used to calculate Cognitive Reflection and numeric ability; a numeracy scale was also administered. Numeric ability, measured on the CRT or the numeracy scale, accounted for the CRT's ability to predict more normative decisions (a subscale of decision-making competence, incentivized measures of impatient and risk-averse choice, and self-reported financial outcomes); Cognitive Reflection contributed no independent predictive power. Results were similar whether the two abilities were modeled (Study 1) or calculated using proportions (Studies 1 and 2). These findings demonstrate numeric ability as a robust predictor of superior decision making across multiple tasks and outcomes. They also indicate that correlations of decision performance with the CRT are insufficient evidence to implicate overriding intuitions in the decision-making biases and outcomes we examined. Numeric ability appears to be the key mechanism instead.

  10. Low reflectance high power RF load

    Science.gov (United States)

    Ives, R. Lawrence; Mizuhara, Yosuke M.

    2016-02-02

    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  11. UCN anomalous losses and the UCN capture cross section on material defects

    International Nuclear Information System (INIS)

    Serebrov, A.; Romanenko, N.; Zherebtsov, O.; Lasakov, M.; Vasiliev, A.; Fomin, A.; Geltenbort, P.; Krasnoshekova, I.; Kharitonov, A.; Varlamov, V.

    2005-01-01

    Experimental data shows anomalously large ultra cold neutrons (UCN) reflection losses and that the process of UCN reflection is not completely coherent. UCN anomalous losses under reflection cannot be explained in the context of neutron optics calculations. UCN losses by means of incoherent scattering on material defects are considered and cross-section values calculated. The UCN capture cross section on material defects is enhanced by a factor of 10 4 due to localization of UCN around defects. This phenomenon can explain anomalous losses of UCN

  12. Near zero reflection by nanostructured anti-reflection coating design for Si substrates

    Science.gov (United States)

    Al-Fandi, Mohamed; Makableh, Yahia F.; Khasawneh, Mohammad; Rabady, Rabi

    2018-05-01

    The nanostructure design of near zero reflection coating for Si substrates by using ZnO Nanoneedles (ZnONN) is performed and optimized for the visible spectral range. The design investigates the ZnONN tip to body ratio effect on the anti-reflection coating properties. Different tip to body ratios are used on Si substrates. Around zero reflection is achieved by the Nanoneedles structure design presented in this work, leading to minimal reflection losses from the Si surface. The current design evolves a solution to optical losses and surface contamination effects associated with Si solar cells.

  13. Reflection seismic methods applied to locating fracture zones in crystalline rock

    International Nuclear Information System (INIS)

    Juhlin, C.

    1998-01-01

    The reflection seismic method is a potentially powerful tool for identifying and localising fracture zones in crystalline rock if used properly. Borehole sonic logs across fracture zones show that they have reduced P-wave velocities compared to the surrounding intact rock. Diagnostically important S-wave velocity log information across the fracture zones is generally lacking. Generation of synthetic reflection seismic data and subsequent processing of these data show that structures dipping up towards 70 degrees from horizontal can be reliably imaged using surface seismic methods. Two real case studies where seismic reflection methods have been used to image fracture zones in crystalline rock are presented. Two examples using reflection seismic are presented. The first is from the 5354 m deep SG-4 borehole in the Middle Urals, Russia where strong seismic reflectors dipping from 25 to 50 degrees are observed on surface seismic reflection data crossing over the borehole. On vertical seismic profile data acquired in the borehole, the observed P-wave reflectivity is weak from these zones, however, strong converted P to S waves are observed. This can be explained by the source of the reflectors being fracture zones with a high P wave to S wave velocity ratio compared to the surrounding rock resulting in a high dependence on the angle of incidence for the reflection coefficient. A high P wave to S wave velocity ratio (high Poisson's ratio) is to be expected in fluid filled fractured rock. The second case is from Aevroe, SE Sweden, where two 1 km long crossing high resolution seismic reflection lines were acquired in October 1996. An E-W line was shot with 5 m geophone and shotpoint spacing and a N-S one with 10 m geophone and shotpoint spacing. An explosive source with a charge size of 100 grams was used along both lines. The data clearly image three major dipping reflectors in the upper 200 ms (600 m). The dipping ones intersect or project to the surface at/or close to

  14. Polarization contrast in reflection near-field optical microscopy with uncoated fibre tips

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Langbein, Wolfgang; Hvam, Jørn Märcher

    1999-01-01

    Using cross-hatched, patterned semiconductor surfaces and round 20-nm-thick gold pads on semiconductor wafers, we investigate the imaging characteristics of a reflection near-field optical microscope with an uncoated fibre tip for different polarization configurations and light wavelengths....... Is is shown that cross-polarized detection allows one to effectively suppress far-field components in the detected signal and to realise imaging of optical contrast on the sub-wavelength scale. The sensitivity window of our microscope, i.e. the scale on which near-field optical images represent mainly optical...

  15. Workplace diaries promoting reflective practice in radiation therapy

    International Nuclear Information System (INIS)

    Chapman, Naomi; Dempsey, Shane E.; Warren-Forward, Helen M.

    2009-01-01

    Competency standards usually describe that radiation therapists are expected to display characteristics of reflective practice. Many radiation therapists may be unequipped to undertake reflective practice or produce evidence of reflective practice due to limited understanding of the process. There are many models to guide practitioners in their reflective journeys, however, the literature describing reflective practice can appear confusing. This paper will discuss the role of reflective practice, provide a definition for reflective practice and define concepts central to reflective journaling or workplace diaries. The paper will offer practical advice to increase radiation therapists knowledge and skills in the use of reflective workplace diaries.

  16. Workplace diaries promoting reflective practice in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Naomi [Medical Radiation Science, Faculty of Health Science, Box 16 Hunter Building, University of Newcastle, Callaghan, NSW 2308 (Australia)], E-mail: naomi.chapman@newcastle.edu.au; Dempsey, Shane E. [Medical Radiation Science, Faculty of Health Science, Box 16 Hunter Building, University of Newcastle, Callaghan, NSW 2308 (Australia)], E-mail: shane.e.dempsey@newcastle.edu.au; Warren-Forward, Helen M. [Medical Radiation Science, Faculty of Health Science, Box 16 Hunter Building, University of Newcastle, Callaghan, NSW 2308 (Australia)], E-mail: helen.warren-forward@newcastle.edu.au

    2009-05-15

    Competency standards usually describe that radiation therapists are expected to display characteristics of reflective practice. Many radiation therapists may be unequipped to undertake reflective practice or produce evidence of reflective practice due to limited understanding of the process. There are many models to guide practitioners in their reflective journeys, however, the literature describing reflective practice can appear confusing. This paper will discuss the role of reflective practice, provide a definition for reflective practice and define concepts central to reflective journaling or workplace diaries. The paper will offer practical advice to increase radiation therapists knowledge and skills in the use of reflective workplace diaries.

  17. Theory of relativistic radiation reflection from plasmas

    Science.gov (United States)

    Gonoskov, Arkady

    2018-01-01

    We consider the reflection of relativistically strong radiation from plasma and identify the physical origin of the electrons' tendency to form a thin sheet, which maintains its localisation throughout its motion. Thereby, we justify the principle of relativistic electronic spring (RES) proposed in [Gonoskov et al., Phys. Rev. E 84, 046403 (2011)]. Using the RES principle, we derive a closed set of differential equations that describe the reflection of radiation with arbitrary variation of polarization and intensity from plasma with an arbitrary density profile for an arbitrary angle of incidence. We confirm with ab initio PIC simulations that the developed theory accurately describes laser-plasma interactions in the regime where the reflection of relativistically strong radiation is accompanied by significant, repeated relocation of plasma electrons. In particular, the theory can be applied for the studies of plasma heating and coherent and incoherent emissions in the RES regime of high-intensity laser-plasma interaction.

  18. The playful and reflective game designer

    DEFF Research Database (Denmark)

    Majgaard, Gunver

    2014-01-01

    Abstract: A group of first-semester engineering students participated in a game design course. The aim of the course was to learn how to design computer games and programming skills by creating their own games, thereby applying their game-playing experiences to gain knowledge about game design....... The aim was for students to develop a more critically reflective perspective on video games and game design. In applying their game experiences, they developed their own digital prototypes and participated in reflective discussions on the concept of games: what makes them interesting and how...... they are constructed. The students used the GameMaker programming tool, which can be used without any prior programming knowledge. The tool allows for the easy development of 2D game prototypes.The didactic approach was based on play as a lever for the design process, and on constructionistic and reflective learning...

  19. FORMATIVE AND REFLECTIVE MODELS IN MARKETING RESEARCH

    Directory of Open Access Journals (Sweden)

    Claudia Ioana CIOBANU

    2017-06-01

    Full Text Available Compliance with the construct validity criteria is necessary for the correct assessment of the research in terms of quality and for further development of the marketing models. The identification of formative and reflective constructs as well as the correct testing of their validity and reliability are important methodological steps for marketing research as described in this article. The first part defines the reflective and the formative constructs and highlighst their particularities by analysing the theoretical criteria that differentiate them. In the second part of the study aspects of validity and trust for the formative and reflective constructs are presented as well as some empirical considerations from research literature regarding their measurement.

  20. Investigating murals with terahertz reflective tomography

    Science.gov (United States)

    Yuan, Minjie; Sun, Wenfeng; Wang, Xinke; Wang, Sen; Zhang, Qunxi; Ye, Jiasheng; Zhang, Yan

    2015-08-01

    Terahertz time-domain spectroscopy (THz-TDS) imaging technology has been proposed to be used in the non-invasive detection of murals. THz-TDS images provide structural data of the sample that cannot be obtained with other complementary techniques. In this paper, two types of defects hidden in the plaster used to simulate the cases of defects in the murals, have been investigated by the terahertz reflected time domain spectroscopy imaging system. These preset defects include a leaf slice and a slit built in the plaster. With the terahertz reflective tomography, information about defects has been determined involving the thickness from the surface of sample to the built-in defect, the profile and distribution of the defect. With this THz tomography, different defects with the changes of optical thickness and their relative refractive index have been identified. The application of reflective pulsed terahertz imaging has been extended to the defect detection of the murals.

  1. Reflective article having a sacrificial cathodic layer

    Science.gov (United States)

    Kabagambe, Benjamin; Buchanan, Michael J.; Scott, Matthew S.; Rearick, Brian K.; Medwick, Paul A.; McCamy, James W.

    2017-09-12

    The present invention relates to reflective articles, such as solar mirrors, that include a sacrificial cathodic layer. The reflective article, more particularly includes a substrate, such as glass, having a multi-layered coating thereon that includes a lead-free sacrificial cathodic layer. The sacrificial cathodic layer includes at least one transition metal, such as a particulate transition metal, which can be in the form of flakes (e.g., zinc flakes). The sacrificial cathodic layer can include an inorganic matrix formed from one or more organo-titanates. Alternatively, the sacrificial cathodic layer can include an organic polymer matrix (e.g., a crosslinked organic polymer matrix formed from an organic polymer and an aminoplast crosslinking agent). The reflective article also includes an outer organic polymer coating, that can be electrodeposited over the sacrificial cathodic layer.

  2. Transmission versus reflectance spectroscopy for quantitation

    Science.gov (United States)

    Gardner, Craig M.

    2018-01-01

    The objective of this work was to compare the accuracy of analyte concentration estimation when using transmission versus diffuse reflectance spectroscopy of a scattering medium. Monte Carlo ray tracing of light through the medium was used in conjunction with pure component absorption spectra and Beer-Lambert absorption along each ray's pathlength to generate matched sets of pseudoabsorbance spectra, containing water and six analytes present in skin. PLS regression models revealed an improvement in accuracy when using transmission compared to reflectance for a range of medium thicknesses and instrument noise levels. An analytical expression revealed the source of the accuracy degradation with reflectance was due both to the reduced collection efficiency for a fixed instrument etendue and to the broad pathlength distribution that detected light travels in the medium before exiting from the incident side.

  3. A Declarative Approach to Architectural Reflection

    DEFF Research Database (Denmark)

    Ingstrup, Mads; Hansen, Klaus Marius

    2005-01-01

    which both creates runtime models of specific distributed architectures and allow for evaluation of AQL queries on these models. We illustrate the viability of the approach in two particular applications of such a model: constraint checking relative to an architectural style, and reasoning about certain......Recent research shows runtime architectural reflection is instrumental in, for instance, building adaptive and flexible systems or checking correspondence between design and implementation. Moreover, experience with computational reflection in various branches of computer science shows...... that the interface through which the meta-information of the running system is accessed, and possibly modified, lies at the heart of designing reflective systems. This paper proposes that such an interface should be like a database: accessed through queries expressed using the concepts with which architecture...

  4. Pigments which reflect infrared radiation from fire

    Science.gov (United States)

    Berdahl, Paul H.

    1998-01-01

    Conventional paints transmit or absorb most of the intense infrared (IR) radiation emitted by fire, causing them to contribute to the spread of fire. The present invention comprises a fire retardant paint additive that reflects the thermal IR radiation emitted by fire in the 1 to 20 micrometer (.mu.m) wavelength range. The important spectral ranges for fire control are typically about 1 to about 8 .mu.m or, for cool smoky fires, about 2 .mu.m to about 16 .mu.m. The improved inventive coatings reflect adverse electromagnetic energy and slow the spread of fire. Specific IR reflective pigments include titanium dioxide (rutile) and red iron oxide pigments with diameters of about 1 .mu.m to about 2 .mu.m and thin leafing aluminum flake pigments.

  5. Defining SNAP by cross-sectional and longitudinal definitions of neurodegeneration

    OpenAIRE

    Wisse, L.E.M.; Das, S.R.; Davatzikos, C.; Dickerson, B.C.; Xie, S.X.; Yushkevich, P.A.; Wolk, D.A.

    2018-01-01

    Introduction: Suspected non-Alzheimer's pathophysiology (SNAP) is a biomarker driven designation that represents a heterogeneous group in terms of etiology and prognosis. SNAP has only been identified by cross-sectional neurodegeneration measures, whereas longitudinal measures might better reflect “active” neurodegeneration and might be more tightly linked to prognosis. We compare neurodegeneration defined by cross-sectional ‘hippocampal volume’ only (SNAP/L−) versus both cross-sectional and ...

  6. Self-Reflection and Academic Performance: Is There a Relationship?

    Science.gov (United States)

    Lew, Magdeleine D. N.; Schmidt, Henk G.

    2011-01-01

    The purposes of the present study were two-fold: first, to evaluate whether reflection journal writing was effective in promoting self-reflection and learning, and whether students become better at self-reflection if they engage continuously in reflection journal writing. To that end, the reflection journals of 690 first-year applied science…

  7. Pullback and pushout crossed polymodules

    Indian Academy of Sciences (India)

    Crossed module; polygroup; crossed polymodule; action; pullback; pushout; fundamental relation. Mathematics Subject Classification. 13D99, 20N20, 18D35. 1. Introduction. Crossed module was defined by Whitehad in [21] and many have worked on this sub- ject. There are many examples of crossed module such as ...

  8. Water Pollution Detection by Reflectance Measurements

    Science.gov (United States)

    Goolsby, A. D.

    1971-01-01

    Measurement of the intensity of light reflected from various planar liquid surfaces has been performed. The results of this brief study show that the presence of a film of foreign material floating on a reference substrate is easily detected by reflectance measurement if the two liquids possess significantly different refractive indices, for example, oil (n = 1.40) and water (n = 1.33). Additional study of various optical configurations, and the building and testing of a prototype monitoring device revealed that the method is sufficiently practical for application to continuous water quality monitoring.

  9. Reflections on 25 Years of Journal Editorship

    Science.gov (United States)

    Matthews, Michael R.

    2015-07-01

    These reflections range over some distinctive features of the journal Science & Education, they acknowledge in a limited way the many individuals who over the past 25 years have contributed to the success and reputation of the journal, they chart the beginnings of the journal, and they dwell on a few central concerns—clear writing and the contribution of HPS to teacher education. The reflections also revisit the much-debated and written-upon philosophical and pedagogical arguments occasioned by the rise and possible demise of constructivism in science education.

  10. Reflection technique for thermal mapping of semiconductors

    Science.gov (United States)

    Walter, Martin J.

    1989-06-20

    Semiconductors may be optically tested for their temperatures by illuminating them with tunable monochromatic electromagnetic radiation and observing the light reflected off of them. A transition point will occur when the wavelength of the light corresponds with the actual band gap energy of the semiconductor. At the transition point, the image of the semiconductor will appreciably darken as the light is transmitted through it, rather than being reflected off of it. The wavelength of the light at the transition point corresponds to the actual band gap energy and the actual temperature of the semiconductor.

  11. Liquid Carbon Reflectivity at 19 nm

    Directory of Open Access Journals (Sweden)

    Riccardo Mincigrucci

    2015-01-01

    Full Text Available We hereby report on a pump-probe reflectivity experiment conducted on amorphous carbon, using a 780 nm laser as a pump and a 19 nm FEL emission as probe. Measurements were performed at 50 degrees with respect to the surface normal to have an un-pumped reflectivity higher than 0.5%. A sub-10 fs time synchronization error could be obtained exploiting the nearly jitter-free capabilities of FERMI. EUV FEL-based experiments open the way to study the behaviour of a liquid carbon phase being unaffected by plasma screening.

  12. Resolution of Reflection Seismic Data Revisited

    DEFF Research Database (Denmark)

    Hansen, Thomas Mejer; Mosegaard, Klaus; Zunino, Andrea

    The Rayleigh Principle states that the minimum separation between two reflectors that allows them to be visually separated is the separation where the wavelet maxima from the two superimposed reflections combine into one maximum. This happens around Δtres = λb/8, where λb is the predominant...... lower vertical resolution of reflection seismic data. In the following we will revisit think layer model and demonstrate that there is in practice no limit to the vertical resolution using the parameterization of Widess (1973), and that the vertical resolution is limited by the noise in the data...

  13. Gravitational wave sources: reflections and echoes

    Science.gov (United States)

    Price, Richard H.; Khanna, Gaurav

    2017-11-01

    The recent detection of gravitational waves has generated interest in alternatives to the black hole interpretation of sources. A subset of such alternatives involves a prediction of gravitational wave ‘echoes’. We consider two aspects of possible echoes: first, general features of echoes coming from spacetime reflecting conditions. We find that the detailed nature of such echoes does not bear any clear relationship to quasi-normal frequencies. Second, we point out the pitfalls in the analysis of local reflecting ‘walls’ near the horizon of rapidly rotating black holes.

  14. Gravitational wave sources: reflections and echoes

    International Nuclear Information System (INIS)

    Price, Richard H; Khanna, Gaurav

    2017-01-01

    The recent detection of gravitational waves has generated interest in alternatives to the black hole interpretation of sources. A subset of such alternatives involves a prediction of gravitational wave ‘echoes’. We consider two aspects of possible echoes: first, general features of echoes coming from spacetime reflecting conditions. We find that the detailed nature of such echoes does not bear any clear relationship to quasi-normal frequencies. Second, we point out the pitfalls in the analysis of local reflecting ‘walls’ near the horizon of rapidly rotating black holes. (paper)

  15. Reflections on science and the communication sector

    Science.gov (United States)

    Raes, Frank

    2015-04-01

    Reflections on science and the communication sector. In this contribution I will reflect about successes and failures in communicating climate change and air pollution sciences to the general public. These communication efforts included writing popular articles, giving public presentations, working with people from the social scientists and artists. Giving the fact that communication is a very important (economic) sector on its own, the question is to what extent scientists should enter that sector, whether scientists are at all accepted in that sector, whether they should use the expertise in that sector, or whether they should merely provide the knowledge to be used by that sector.

  16. [Around biological evolution. Reflections of a physicist].

    Science.gov (United States)

    Sanchez-Palencia, Evariste

    2016-01-01

    This text is the written version of a talk at the Société de Biologie on February 17, 2016. It contains reflections of a non-biologist scientist on general problems of biological evolution, including the kind of causality involved, the ideas emerging from it, in particular the constructive and structuring character of phenomena such as predation, the role of stability and attractors. This leads to a larger reflection on dialectics, the general framework of evolving processes, which overpasses formal logic and instantaneousness. © Société de Biologie, 2016.

  17. Temporal processes involved in simultaneous reflection masking

    DEFF Research Database (Denmark)

    Buchholz, Jörg

    2006-01-01

    reflection delays and enhances the test reflection for large delays. Employing a 200-ms-long broadband noise burst as input signal, the critical delay separating these two binaural phenomena was found to be 7–10 ms. It was suggested that the critical delay refers to a temporal window that is employed......, resulting in a critical delay of about 2–3 ms for 20-ms-long stimuli. Hence, for very short stimuli the temporal window or critical delay exhibits values similar to the auditory temporal resolution as, for instance, observed in gap-detection tasks. It is suggested that the larger critical delay observed...

  18. X-ray reflectivity and surface roughness

    International Nuclear Information System (INIS)

    Ocko, B.M.

    1988-01-01

    Since the advent of high brightness synchrotron radiation sources there has been a phenomenal growth in the use of x-rays as a probe of surface structure. The technique of x-ray reflectivity is particularly relevant to electrochemists since it is capable of probing the structure normal to an electrode surface in situ. In this paper the theoretical framework for x-ray reflectivity is reviewed and the results from previous non-electrochemistry measurements are summarized. These measurements are from the liquid/air interface (CCl 4 ), the metal crystal vacuum interface (Au(100)), and from the liquid/solid interface(liquid crystal/silicon). 34 refs., 5 figs

  19. Cross-language psycholinguistics

    NARCIS (Netherlands)

    Cutler, A.

    1985-01-01

    Cross-linguistic research can be of valaue to psycholinguistics by allowing tests of hypotheses the testing of which would be severely confounded in a single language, and by providing simple and readily available control conditions. For a long time the resources of this kind of research were

  20. Cross-Cultural Psychology.

    Science.gov (United States)

    Triandis, Harry C.; Brislin, Richard W.

    Cross-Cultural psychology refers to the collective efforts of researchers who work among people who live in different societies, with different languages and different forms of government. There are a number of benefits to the study of human behavior which can be accrued by carrying out research in various cultures, largely concerned with better…