WorldWideScience

Sample records for revisited stm imaging

  1. Near-Field Imaging with Sound: An Acoustic STM Model

    Science.gov (United States)

    Euler, Manfred

    2012-01-01

    The invention of scanning tunneling microscopy (STM) 30 years ago opened up a visual window to the nano-world and sparked off a bunch of new methods for investigating and controlling matter and its transformations at the atomic and molecular level. However, an adequate theoretical understanding of the method is demanding; STM images can be…

  2. Bulk Copper Electrodeposition on Gold Imaged by In Situ STM

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Bech-Nielsen, Gregers; Møller, Per

    1996-01-01

    . After the first cycle of copper deposition and dissolution the morphology of the polycrystalline gold surface had apparently changed into a recrystallized phase of a copper-gold alloy. At a given stage of the cycle the potential of the electrode was found to depend linearly on the tip potential......Electrochemical measurements were carried out simultaneously with acquisition of in situ STM images of copper electrodeposition at low cathodic overpotentials and subsequent dissolution from the underlying polycrystalline gold surfaces. The morphologies of the copper deposits were examined...... for correlation with features of the current-voltage diagram. Copper growth is by nucleation and formation of 3D islands. During the initial stages of bulk copper growth the potentials were fixed at selected values and a balance observed between formation of polycrystalline copper nuclei and of copper crystals...

  3. Electronic structure and STM imaging of the KBr-InSb interface

    Energy Technology Data Exchange (ETDEWEB)

    Ciochoń, Piotr, E-mail: ciochon.piotr@gmail.com; Olszowska, Natalia; Kołodziej, Jacek J.

    2017-07-01

    Highlights: • The structure of the InSb (001) surface covered with thin KBr layers is reported. • KBr growth does not perturb strongly the structure of a clean InSb surface. • A model of the system with KBr treated as a thin dielectric layer is proposed. • The atomic structure of the KBr-InSb interface is directly imaged using STM. - Abstract: We study the properties of the InSb (001) surface covered with ultrathin KBr films, with a thickness of 1–4 ML. KBr deposition does not strongly perturb the crystallographic structure of the InSb surface and the electronic structure of the substrate also remains unaffected by the overlayer. A simple model of the studied system is proposed, in which a thin KBr layer is treated as a dielectric film, modifying potential barrier for the electrons tunneling to/from the InSb substrate. Apparent step heights on the KBr film, measured using scanning tunneling microscope (STM), agree well with the predictions of the model and the atomically-resolved STM images show the structure of the InSb-KBr interface. Our results demonstrate that STM may be used as a tool for investigations of the semiconductor–insulator interfaces.

  4. Imaging isodensity contours of molecular states with STM

    Science.gov (United States)

    Reecht, Gaël; Heinrich, Benjamin W.; Bulou, Hervé; Scheurer, Fabrice; Limot, Laurent; Schull, Guillaume

    2017-11-01

    We present an improved way for imaging the density of states of a sample with a scanning tunneling microscope, which consists in mapping the surface topography while keeping the differential conductance (dI/dV) constant. When archetypical C60 molecules on Cu(111) are imaged with this method, these so-called iso-dI/dV maps are in excellent agreement with theoretical simulations of the isodensity contours of the molecular orbitals. A direct visualization and unambiguous identification of superatomic C60 orbitals and their hybridization is then possible.

  5. First-Principles Study on the Stability and STM Image of Borophene

    Science.gov (United States)

    Luo, Zhifen; Fan, Xiaoli; An, Yurong

    2017-08-01

    Very recently, borophene (atomic-thin two-dimensional boron sheet) has been successfully synthesized on the Ag(111) surface by deposition. Two kinds of structures were found. However, the identification of the monolayer boron sheets grown on the metal substrate, as well as the stability of different 2D boron sheets, is controversial. By performing the first-principles calculations, present study investigates the atomic structure, stability, and electronic properties of the most possible boron sheets grown on metal surface, namely, buckled triangular, β12, and χ3 types of crystal lattice. Our result shows that all the three freestanding sheets are thermodynamically unstable and all are metallic. On the other hand, our result indicates the Ag(111) substrate stabilize these sheets. Additionally, our simulated STM images of these monoatomic-thin boron sheets on Ag(111) surface reproduce the experiment observations well and clearly identify the as-grown boron sheets.

  6. Electronic structure of the cuprate superconducting and pseudogap phases from spectroscopic imaging STM

    Science.gov (United States)

    Schmidt, A. R.; Fujita, K.; Kim, E.-A.; Lawler, M. J.; Eisaki, H.; Uchida, S.; Lee, D.-H.; Davis, J. C.

    2011-06-01

    We survey the use of spectroscopic imaging scanning tunneling microscopy (SI-STM) to probe the electronic structure of underdoped cuprates. Two distinct classes of electronic states are observed in both the d-wave superconducting (dSC) and the pseudogap (PG) phases. The first class consists of the dispersive Bogoliubov quasiparticle excitations of a homogeneous d-wave superconductor, existing below a lower energy scale E=Δ0. We find that the Bogoliubov quasiparticle interference (QPI) signatures of delocalized Cooper pairing are restricted to a k-space arc, which terminates near the lines connecting k=±(π/a0,0) to k=±(0,π/a0). This arc shrinks continuously with decreasing hole density such that Luttinger's theorem could be satisfied if it represents the front side of a hole-pocket that is bounded behind by the lines between k=±(π/a0,0) and k=±(0,π/a0). In both phases, the only broken symmetries detected for the |E|translational symmetries, coexist with this intra-unit-cell electronic symmetry breaking at E=Δ1. Their characteristic wavevector Q is determined by the k-space points where Bogoliubov QPI terminates and therefore changes continuously with doping. The distinct broken electronic symmetry states (intra-unit-cell and finite Q) coexisting at E~Δ1 are found to be indistinguishable in the dSC and PG phases. The next challenge for SI-STM studies is to determine the relationship of the E~Δ1 broken symmetry electronic states with the PG phase, and with the E<Δ0 states associated with Cooper pairing.

  7. Electronic structure, total energies, and STM images of clean and oxygen-covered Al(111)

    DEFF Research Database (Denmark)

    Jacobsen, Joachim; Hammer, Bjørk; Jacobsen, Karsten Wedel

    1995-01-01

    an attractive O-O interaction is identified together with an enhancement in the dipole moment induced per O atom. Finally, Tersoff-Hamann-type scanning tunneling microscopy (STM) topographs are derived based on the calculated one-electron wave functions and spectra. For the clean Al(111) a theoretical STM...

  8. Quantitative and high-resolution magnetic images obtained by STM-SQUID microscope with distance modulation technique

    Science.gov (United States)

    Yokocho, T.; Akaba, H. S.; Miyato, Y.

    2017-07-01

    We have developed an STM-SQUID microscope, in which a scanning tunnelling microscope (STM) is combined with an rf-SQUID. The issue in our STM-SQUID microscope was that the obtained magnetic image was not the same as the sample’s ideal magnetic field distribution. This was because the magnetic image could be affected not only by the sample’s local magnetic field distribution, but also by the magnetic field distribution above the sample, namely “background field”. In this work, we applied the distance modulation technique to our microscope. In this technique, the change of the SQUID output signal was detected while the distance between the sample and the probe tip was modulated in a constant amplitude. As a result, the influence of the background field was cancelled out, and the magnetic information near the sample surface was largely extracted. We successfully obtained the quantitative magnetic images in ~100 nm spatial resolution by using the distance modulation technique.

  9. Surface analysis with STM and AFM

    CERN Document Server

    Magonov, Sergi N

    1996-01-01

    Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) are powerful tools for surface examination. In the past, many STM and AFM studies led to erroneous conclusions due to lack of proper theoretical considerations and of an understanding of how image patterns are affected by measurement conditions. For this book, two world experts, one on theoretical analysis and the other on experimental characterization, have joined forces to bring together essential components of STM and AFM studies: The practical aspects of STM, the image simulation by surface electron density plot calculat

  10. Revisiting Stephan's Quintet with deep optical images

    Science.gov (United States)

    Duc, Pierre-Alain; Cuillandre, Jean-Charles; Renaud, Florent

    2018-01-01

    Stephan's Quintet, a compact group of galaxies, is often used as a laboratory to study a number of phenomena, including physical processes in the interstellar medium, star formation, galaxy evolution, and the formation of fossil groups. As such, it has been subject to intensive multi-wavelength observation campaigns. Yet, models lack constrains to pin down the role of each galaxy in the assembly of the group. We revisit here this system with multi-band deep optical images obtained with MegaCam on the Canada-France-Hawaii Telescope (CFHT), focusing on the detection of low surface brightness (LSB) structures. They reveal a number of extended LSB features, some new, and some already visible in published images but not discussed before. An extended diffuse, reddish, lopsided, halo is detected towards the early-type galaxy NGC 7317, the role of which had so far been ignored in models. The presence of this halo made of old stars may indicate that the group formed earlier than previously thought. Finally, a number of additional diffuse filaments are visible, some close to the foreground galaxy NGC 7331 located in the same field. Their structure and association with mid-IR emission suggest contamination by emission from Galactic cirrus.

  11. Revisiting Stephan's Quintet with deep optical images

    Science.gov (United States)

    Duc, Pierre-Alain; Cuillandre, Jean-Charles; Renaud, Florent

    2018-03-01

    Stephan's Quintet, a compact group of galaxies, is often used as a laboratory to study a number of phenomena, including physical processes in the interstellar medium, star formation, galaxy evolution, and the formation of fossil groups. As such, it has been subject to intensive multiwavelength observation campaigns. Yet, models lack constrains to pin down the role of each galaxy in the assembly of the group. We revisit here this system with multiband deep optical images obtained with MegaCam on the Canada-France-Hawaii Telescope (CFHT), focusing on the detection of low surface brightness (LSB) structures. They reveal a number of extended LSB features, some new, and some already visible in published images but not discussed before. An extended diffuse, reddish, lopsided, halo is detected towards the early-type galaxy NGC 7317, the role of which had so far been ignored in models. The presence of this halo made of old stars may indicate that the group formed earlier than previously thought. Finally, a number of additional diffuse filaments are visible, some close to the foreground galaxy NGC 7331 located in the same field. Their structure and association with mid-infrared emission suggest contamination by emission from Galactic cirrus.

  12. Understanding atomic-resolved STM images on TiO{sub 2}(110)-(1 x 1) surface by DFT calculations

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Sanchez, C; Gonzalez, C; Mendez, J; De Andres, P L; MartIn-Gago, J A; Lopez, M F [Instituto Ciencia de Materiales de Madrid (CSIC), C/Sor Juana Ines de la Cruz 3, 28049-Madrid (Spain); Jelinek, P, E-mail: mflopez@icmm.csic.es [Institute of Physics, Czech Academy of Sciences, Cukrovarnicka 10, 162 53-Prague (Czech Republic)

    2010-10-08

    We present a combination of experimental STM images and DFT calculations to understand the atomic scale contrast of features found in high-resolution STM images. Simulating different plausible structural models for the tip, we have been able to reproduce various characteristics previously reported in experimental images on TiO{sub 2}(110)-(1 x 1) under controlled UHV conditions. Our results allow us to determine the influence of different chemical and morphological tip terminations on the atomic-resolution STM images of the TiO{sub 2}(110)-(1 x 1) surface. The commonest images have been properly explained using standard models for a W tip, either clean or with a single O atom located at the apex. Furthermore, a double transfer of oxygen atoms can account for different types of bizarre atomic-resolution features occasionally seen, and not conclusively interpreted before. Importantly, we discuss how typical point-defects are imaged on this surface by different tips, namely bridging O vacancies and adsorbed OH groups.

  13. In situ STM imaging and direct electrochemistry of Pyrococcus furiosus ferredoxin assembled on thiolate-modified Au(111) surfaces

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Christensen, Hans Erik Mølager; Ooi, Bee Lean

    2004-01-01

    by surface microscopic structures of PfFd monolayers, as revealed by scanning tunneling microscopy under potential control (in situ STM). Direct ET between PfFd in phosphate buffer solution, pH 7.9, and EPG electrodes is observed in the presence of promoters. Neomycin gives rise to a pair of redox peaks......We have addressed here electron transfer (ET) of Pyrococcus furiosus ferredoxin (PfFd, 7.5 kDa) in both homogeneous solution using edge plane graphite (EPG) electrodes and in the adsorbed state by electrochemistry on surface-modified single-crystal Au(111) electrodes, This has been supported...... or submonolayers. Highly ordered (2root3 x 5)R30degrees cluster structures with six MPA molecules in each cluster were found by in situ STM. Individual PfFd molecules on the MPA layer are well resolved by in situ STM. Under Ar protection reversible cyclic voltammograms were obtained on PfFd-MPA/Au(111) and Pf...

  14. STM images of a large organic molecule adsorbed on a bare metal substrate or on a thin insulating layer: Visualization of HOMO and LUMO

    Science.gov (United States)

    Villagomez, Carlos Javier; Zambelli, Tomaso; Gauthier, Sébastien; Gourdon, André; Stojkovic, Sladjana; Joachim, Christian

    2009-06-01

    An isomer of the methylterrylene molecule was adsorbed both on Cu(111) and on a NaCl bilayer deposited on Cu(111) and imaged by ultra high vacuum scanning tunneling microscopy at low temperature (5 K). On the bare metal surface, the STM images do not reveal any intramolecular resolution and do not depend on the applied tunnel bias. On the contrary, the images acquired at specific bias voltages for the molecule on the salt layer show a striking similarity with the spatial distribution of the electronic probability density in the highest occupied molecular orbital (HOMO) and in the lowest unoccupied molecular orbital (LUMO) of free methylterrylene. They are well reproduced by elastic scattering quantum chemistry calculations. These data provide a direct view of the hyperconjugative interaction between the methyl group and the frontier orbitals of terrylene.

  15. Pseudomembranous colitis revisited: spectrum of imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, I. [Department of Radiology, Leicester Royal Infirmary, University Hospitals of Leicester NHS Trust, Leicester LE1 5WW (United Kingdom); Sinha, R. [Department of Radiology, Leicester Royal Infirmary, University Hospitals of Leicester NHS Trust, Leicester LE1 5WW (United Kingdom)]. E-mail: rakesh.sinha@swh.nhs.uk; Rodgers, P. [Department of Radiology, Leicester Royal Infirmary, University Hospitals of Leicester NHS Trust, Leicester LE1 5WW (United Kingdom)

    2006-07-15

    In recent years there has been a marked increase in the incidence of pseudomembranous colitis (PMC). PMC is more common in patients over 65 years of age and can cause significant morbidity. The purpose of this article is to review the imaging features of PMC on plain radiography, sonography, computed tomography (CT), scintigraphy and magnetic resonance imaging (MRI). It is important to recognize the imaging findings of PMC using different imaging methods and encourage urgent confirmation of the diagnosis serologically, as the differential includes other fulminant colitides for which colectomy may be the required. Awareness of the spectrum of imaging findings of PMC can help radiologists make the primary or incidental diagnosis of PMC.

  16. Revisitation: a trans phenomenology of the media image

    Directory of Open Access Journals (Sweden)

    Cael M Keegan

    2016-12-01

    Full Text Available How might certain moving images move us into transgender becoming? The recent proliferation of transgender images in the media of the Global North has been widely regarded as supporting transgender political and social equality. But do these images do justice to the complexity of transgender lives? Who are images of transgender identity made for, and whose interests do they serve? Instead of discussing media that produce a transgender object for public consumption, this essay’s author is interested in theorizing a trans point of media reception for the popular image. This essay illustrates how transgender subjects might fashion their own archives of becoming through encounters with media that unintentionally support transgender embodiment as a possibility in the world. Revisiting his phenomenological encounters with the film Under the Skin and the “Milk: It Does a Body Good” ad campaign, the author analyzes how certain media objects have the unexpected power to “move” the transgender subject into becoming.

  17. Using destination image to predict visitors' intention to revisit three Hudson River Valley, New York, communities

    Science.gov (United States)

    Rudy M. Schuster; Laura Sullivan; Duarte Morais; Diane Kuehn

    2009-01-01

    This analysis explores the differences in Affective and Cognitive Destination Image among three Hudson River Valley (New York) tourism communities. Multiple regressions were used with six dimensions of visitors' images to predict future intention to revisit. Two of the three regression models were significant. The only significantly contributing independent...

  18. Ab initio STM and STS simulations on magnetic and nonmagnetic metallic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Dick, Alexey

    2008-04-14

    The aim of this work was to provide an in-depth understanding of a new generation of scan- ning tunneling microscopy experiments, performed employing different regimes of the STM: the spectroscopy-mode (the so-called Fourier Transformed STM, FT-STM), and the spin-sensitive mode (the so-called spin-polarized STM, SP-STM). In the present thesis ab initio tools are proposed that are based on DFT calculations to theoretically predict and analyze such types of the STM. The first part of this thesis focusses on the simulation of FT-STM, the mode that allows to probe local dispersion properties of the electrons at the surface. In order to provide the theoretical counterpart of the experimental FT-STM spectra we have introduced a new implicit approach that is derived from Tersoff-Hamann theory of the STM. The importance of an accurate description of surface wavefunctions at 5-15 A above the surface as well as the spurious quantum- size effects have been discussed in detail together with approaches to obtain converged FT-STM images. We applied our method to FT-STM experiments performed on Ag(110) surfaces. In the second part of the thesis we discuss the modeling of the spin-resolved STM, the mode that allows to characterize the magnetic structure of a surface. As a case system we studied here the magnetically-ordered transition-metal nitride surface Mn{sub 3}N{sub 2}(010). Because SP-STM experiments did not allow a conclusive understanding of the surface structure, we have first employed ab initio thermodynamics to figure out the most stable magnetic and atomic configuration of the surface that are consistent with experiments. To simulate SP-STM images on the most stable Mn{sub 3}N{sub 2}(010) surface we have employed the spin-generalized transfer-Hamiltonian formalism, assuming that the tip wavefunctions have dominant radial symmetry (s-like tip). (orig.)

  19. Revisiting the destination image construct through a conceptual model

    Directory of Open Access Journals (Sweden)

    Nelson Matos

    2012-05-01

    Full Text Available In a highly complex and dynamic sector like tourism, the current economic crisis brings to destination managers not only challenges but also opportunities. The image destinations promote to the market is a key element in the tourist decision-making process when choosing a tourism destination. This paper’s purpose is, therefore, to review and explore the destination image construct and its implications for the destination, and also to present a model of destination image based on previous studies. Implications for creating, enhancing and implementing the correct marketing programs for tourism destinations are provided.

  20. The Kaye effect revisited: High speed imaging of leaping shampoo

    Science.gov (United States)

    Versluis, Michel; Blom, Cock; van der Meer, Devaraj; van der Weele, Ko; Lohse, Detlef

    2003-11-01

    When a visco-elastic fluid such as shampoo or shower gel is poured onto a flat surface the fluid piles up forming a heap on which rather irregular combinations of fluid buckling, coiling and folding are observed. Under specific conditions a string of fluid leaps from the heap and forms a steady jet fed by the incoming stream. Momentum transfer of the incoming jet, combined with the shear-thinning properties of the fluid, lead to a spoon-like dimple in the highly viscous fluid pool in which the jet recoils. The jet can be stable for several seconds. This effect is known as the Kaye effect. In order to reveal its mechanism we analyzed leaping shampoo through high-speed imaging. We studied the jet formation, jet stability and jet disruption mechanisms. We measured the velocity of both the incoming and recoiled jet, which was found to be thicker and slower. By inclining the surface on which the fluid was poured we observed jets leaping at upto five times.

  1. Functionalized molecules studied by STM: motion, switching and reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Grill, Leonhard [Institut fuer Experimentalphysik, Freie Universitaet Berlin, Arnimallee 14, 14195 Berlin (Germany)

    2008-02-06

    Functionalized molecules represent the central issue of molecular nanotechnology. Scanning tunnelling microscopy (STM) is a powerful method to investigate such molecules, because it allows us to image them with sub-molecular resolution when adsorbed on a surface and can be used at the same time as a tool to manipulate single molecules in a controlled way. Such studies permit deep insight into the conformational, mechanical and electronic structure and thus functionalities of the molecules. In this review, recent experiments on specially designed molecules, acting as model systems for molecular nanotechnology, are reviewed. The presented studies focus on key functionalities: lateral rolling and hopping motion on a supporting surface, the switching behaviour of azobenzene derivatives by using the STM tip and the controlled reactivity of molecular side groups, which enable the formation of covalently bound molecular nanoarchitectures. (topical review)

  2. Electrochemical behaviour of gold modified with contaminated TMP amine adlayers studied by STM, CV, EPR

    Energy Technology Data Exchange (ETDEWEB)

    Krukowski, P. [Division of Physics and Technology of Nanometric Structures, Solid State Physics Department, University of Lodz, Pomorska 149/153, 90-236 Lodz (Poland)], E-mail: pkrukowski@std2.phys.uni.lodz.pl; Kowalczyk, P.J. [Division of Physics and Technology of Nanometric Structures, Solid State Physics Department, University of Lodz, Pomorska 149/153, 90-236 Lodz (Poland); Krzyczmonik, P. [Department of General and Inorganic Chemistry, University of Lodz, Narutowicza 68, 90-136 Lodz (Poland); Olejniczak, W.; Klusek, Z.; Puchalski, M. [Division of Physics and Technology of Nanometric Structures, Solid State Physics Department, University of Lodz, Pomorska 149/153, 90-236 Lodz (Poland); Gwozdzinski, K. [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland)

    2009-01-15

    Scanning tunnelling microscopy (STM), cyclic voltammetry (CV) and electron paramagnetic resonance spectroscopy (EPR) were used to investigate the influence of the TMP amine derivative on Au (1 1 1). The STM results show that the gold surface covered by the adlayer of the TMP derivative is easily modified (holes formation) after increasing the bias voltage to 0.5 V. The CV and EPR results show the electrochemical origin of observed STM topography changes. It is suggested that TMP could be oxidized to the nitroxyl TEMPO radical which adsorbs on Au in the form of an oxoammonium cation. Such an oxoammonium cation at the potential of 0.5 V forms a permanent complex of gold and the nitroxyl radical which could be easily desorbed during STM imaging.

  3. Scanning tunneling microscopy III theory of STM and related scanning probe methods

    CERN Document Server

    Güntherodt, Hans-Joachim

    1993-01-01

    While the first two volumes on Scanning Tunneling Microscopy (STM) and its related scanning probe (SXM) methods have mainly concentrated on intro­ ducing the experimental techniques, as well as their various applications in different research fields, this third volume is exclusively devoted to the theory of STM and related SXM methods. As the experimental techniques including the reproducibility of the experimental results have advanced, more and more theorists have become attracted to focus on issues related to STM and SXM. The increasing effort in the development of theoretical concepts for STM/SXM has led to considerable improvements in understanding the contrast mechanism as well as the experimental conditions necessary to obtain reliable data. Therefore, this third volume on STM/SXM is not written by theorists for theorists, but rather for every scientist who is not satisfied by just obtaining real­ space images of surface structures by STM/SXM. After a brief introduction (Chap. 1), N. D. Lang first co...

  4. Toward quantitative STM: Scanning tunneling microscopy study of structure and dynamics of adsorbates on transition metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Dunphy, James Christopher [Univ. of California, Berkeley, CA (United States)

    1995-05-01

    STM was applied to chemisorbed S layers on Re(000l) and Mo(100) surfaces. As function of coverage on both these surfaces, S orders into several different overlayer structures, which have been studied by dynamic LEED. STM images of all these structures were obtained. Approximate location of S atoms in the structures was determined by inspecting the images, especially the regions containing defects. Results are in agreement with LEED except for the p(2xl) overlayer of sulfur on Mo(100). The STM images were compared to calculations made with Electron Scattering Quantum Chemistry (ESQC) theory. Variation of contrast in experimental images is explained as a result of changes in STM tip termination structure. STM image contrast is a result of changes in the interference between different paths for the tunneling electrons. The simplest structure on the Mo(100) surface was used as a model for developing and testing a method of quantitative structure determination with the STM. Experimental STM images acquired under a range of tunneling conditions were compared to theoretical calculations of the images as a function of surface structure to determine the structure which best fit. Results matched within approximately 0.1 Angstroms a LEED structural determination. At lower S coverage, diffusion of S atoms over the Re(0001) surface and the lateral interaction between these atoms were investigated by application of a new image analysis technique. The interaction between the S and a coadsorbed CO layer was also studied, and CO was found to induce compression of the S overlayer. A similar result was found for Au deposited on the sulfur covered Mo(100) surface. The interaction between steps on the Mo surface was found to be influenced by S adsorption and this observation was interpreted with the theory of equilibrium crystal shape. Design of an STM instrument which operates at cryogenic and variable sample temperatures, and its future applications, are described.

  5. STM, SECPM, AFM and Electrochemistry on Single Crystalline Surfaces.

    Science.gov (United States)

    Wolfschmidt, Holger; Baier, Claudia; Gsell, Stefan; Fischer, Martin; Schreck, Matthias; Stimming, Ulrich

    2010-08-05

    Scanning probe microscopy (SPM) techniques have had a great impact on research fields of surface science and nanotechnology during the last decades. They are used to investigate surfaces with scanning ranges between several 100 mm down to atomic resolution. Depending on experimental conditions, and the interaction forces between probe and sample, different SPM techniques allow mapping of different surface properties. In this work, scanning tunneling microscopy (STM) in air and under electrochemical conditions (EC-STM), atomic force microscopy (AFM) in air and scanning electrochemical potential microscopy (SECPM) under electrochemical conditions, were used to study different single crystalline surfaces in electrochemistry. Especially SECPM offers potentially new insights into the solid-liquid interface by providing the possibility to image the potential distribution of the surface, with a resolution that is comparable to STM. In electrocatalysis, nanostructured catalysts supported on different electrode materials often show behavior different from their bulk electrodes. This was experimentally and theoretically shown for several combinations and recently on Pt on Au(111) towards fuel cell relevant reactions. For these investigations single crystals often provide accurate and well defined reference and support systems. We will show heteroepitaxially grown Ru, Ir and Rh single crystalline surface films and bulk Au single crystals with different orientations under electrochemical conditions. Image studies from all three different SPM methods will be presented and compared to electrochemical data obtained by cyclic voltammetry in acidic media. The quality of the single crystalline supports will be verified by the SPM images and the cyclic voltammograms. Furthermore, an outlook will be presented on how such supports can be used in electrocatalytic studies.

  6. STM, SECPM, AFM and Electrochemistry on Single Crystalline Surfaces

    Directory of Open Access Journals (Sweden)

    Ulrich Stimming

    2010-08-01

    Full Text Available Scanning probe microscopy (SPM techniques have had a great impact on research fields of surface science and nanotechnology during the last decades. They are used to investigate surfaces with scanning ranges between several 100 mm down to atomic resolution. Depending on experimental conditions, and the interaction forces between probe and sample, different SPM techniques allow mapping of different surface properties. In this work, scanning tunneling microscopy (STM in air and under electrochemical conditions (EC-STM, atomic force microscopy (AFM in air and scanning electrochemical potential microscopy (SECPM under electrochemical conditions, were used to study different single crystalline surfaces in electrochemistry. Especially SECPM offers potentially new insights into the solid-liquid interface by providing the possibility to image the potential distribution of the surface, with a resolution that is comparable to STM. In electrocatalysis, nanostructured catalysts supported on different electrode materials often show behavior different from their bulk electrodes. This was experimentally and theoretically shown for several combinations and recently on Pt on Au(111 towards fuel cell relevant reactions. For these investigations single crystals often provide accurate and well defined reference and support systems. We will show heteroepitaxially grown Ru, Ir and Rh single crystalline surface films and bulk Au single crystals with different orientations under electrochemical conditions. Image studies from all three different SPM methods will be presented and compared to electrochemical data obtained by cyclic voltammetry in acidic media. The quality of the single crystalline supports will be verified by the SPM images and the cyclic voltammograms. Furthermore, an outlook will be presented on how such supports can be used in electrocatalytic studies.

  7. Mergers, Acquisitions, and Access: STM Publishing Today

    Science.gov (United States)

    Robertson, Kathleen

    Electronic publishing is changing the fundamentals of the entire printing/delivery/archive system that has served as the distribution mechanism for scientific research over the last century and a half. The merger-mania of the last 20 years, preprint pools, and publishers' licensing and journals-bundling plans are among the phenomena impacting the scientific information field. Science-Technology-Medical (STM) publishing is experiencing a period of intense consolidation and reorganization. This paper gives an overview of the economic factors fueling these trends, the major STM publishers, and the government regulatory bodies that referee this industry in Europe, Canada, and the USA.

  8. The Life Cycle of Images: Revisiting the Ethical Treatment of the Art Therapy Image

    Science.gov (United States)

    Hinz, Lisa D.

    2013-01-01

    Using the metaphor of the human life cycle, the author of this viewpoint suggests that consideration of the birth, life, and death of images made in art therapy may promote a new perspective on their ethical treatment. A developmental view of images encourages art therapists to see art images as living entities that undergo a natural life cycle.…

  9. Restructuring STM (Science, Technology, and Mathematics) Education for Entrepreneurship

    Science.gov (United States)

    Ezeudu, F. O.; Ofoegbu, T. O.; Anyaegbunnam, N. J.

    2013-01-01

    This paper discussed the need to restructure STM (science, technology, and mathematics) education to reflect entrepreneurship. This is because the present STM education has not achieved its aim of making graduates self-reliant. Entrepreneurship education if introduced in the STM education will produce graduate who can effectively manage their…

  10. Revealing the structural detail of individual polymers using a combination of electrospray deposition and UHV-STM

    DEFF Research Database (Denmark)

    Jethwa, Siddharth; Madsen, Mikael; Knudsen, Jakob Back

    2017-01-01

    A phenylene vinylene polymer derivative is deposited onto a Au(111) surface under Ultra-High Vacuum (UHV) conditions using electrospray ionisation deposition and characterised using Scanning Tunnelling Microscopy (STM). High resolution STM images reveal the polymer structure on the monomeric scale......, allowing the identification of regioisomerism, the intricate isomerisations of the polymer side-chains, as well as the larger-scale topologies of the polymer strands....

  11. Topographical fingerprints of many-body interference in STM junctions on thin insulating films

    Science.gov (United States)

    Donarini, Andrea; Siegert, Benjamin; Sobczyk, Sandra; Grifoni, Milena

    2012-10-01

    Negative differential conductance is a nonlinear transport phenomenon ubiquitous in molecular nanojunctions. Its physical origin can be the most diverse. In rotationally symmetric molecules with orbitally degenerate many-body states it can be ascribed to interference effects. We establish in this paper a criterion to identify the interference blocking scenario by correlating the spectral and the topographical information achievable in a scanning tunneling microscopy (STM) single-molecule measurement. Simulations of current-voltage characteristics as well as constant-height and constant-current STM images for a Cu-phthalocyanine on a thin insulating film are presented as experimentally relevant examples.

  12. Local correlation of photoemission electron microscopy and STM at a defined cluster substrate system

    Energy Technology Data Exchange (ETDEWEB)

    Rohmer, M.; Wiemann, C.; Munzinger, M.; Guo, L.; Aeschlimann, M.; Bauer, M. [University of Kaiserslautern (Germany). Department of Physics

    2006-01-01

    We describe a technique that enables photoelectron spectroscopy and STM imaging of supported clusters from identical surface areas of a size of a few {mu}m{sup 2} at a lateral resolution in the low nanometer regime. In this way we are able to locally correlate properties regarding the electronic structure of the clusters and their topography. The use of a photoemission electron microscope (PEEM) allows one to probe the local distribution of the photoemission yield. An STM-tip is used to remove clusters from their position and set local, well-defined markers at the surface that are clearly visible in the PEEM images. These markers act as reference points to identify surface areas in the PEEM image that have formerly been imaged by an STM. The present accuracy of this local correlation technique is at least 300 nm. We propose a scheme to further improve this correlation so that in future experiments even selected single clusters, which have been characterized by STM, can be addressed by local photoelectron spectroscopy as well as local time-resolved photoelectron spectroscopy. (orig.)

  13. STM study on the charge order phase of {theta}-(BEDT-TTF){sub 2}RbZn(SCN){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Ichimura, Koichi [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan)], E-mail: ichimura@eng.hokudai.ac.jp; Ikeda, Shigeru; Kawai, Mikiko; Nomura, Kazushige [Department of Physics, Hokkaido University, Sapporo 060-0810 (Japan); Ishioka, Junya; Tanda, Satoshi [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan)

    2009-03-01

    The organic conductor {theta}-(BEDT-TTF){sub 2}RbZn(SCN){sub 4}, which exhibits charge ordering below T{sub CO}=190K, was studied by STM to observe the charge ordering pattern in the real space. The conducting a-c plane was investigated. The donor arrangement in the a-c surface was clearly observed in topographic STM images at room temperature. The STM image shows the rectangular pattern with periods of 1 nm and 0.5 nm along the a- and c-direction, respectively. This means that BEDT-TTF donors located at the center of the rectangle were not observed except a certain scan. The observed STM image is naively expected from the crystal structure of {theta}-(BEDT-TTF){sub 2}RbZn(SCN){sub 4}. We found that all donors can be imaged by the scan along the a-axis. The STM image at 170 K shows the nearly two-fold periodicity along the c-direction. It corresponds to the horizontal stripe charge order pattern.

  14. STM/STS study of superconducting diamond

    Directory of Open Access Journals (Sweden)

    Alexey Troyanovskiy, Terukazu Nishizaki and Evgeniy Ekimov

    2006-01-01

    Full Text Available We present a scanning tunneling microscopy/spectroscopy (STM/STS study of synthetic polycrystalline boron-doped diamond in the temperature range 0.5–4.3 K. At 4.3 K the sample-surface was very non-uniform and tunneling I(V spectra were typical for p-type semiconductors. After cooling below the superconducting transition temperature, we detected and measured the superconducting gap of diamonds. At temperatures around 0.5 K the energy gap was around 0.8 and 1 mV (for two different samples.

  15. STM in poslovne baze podatkov v Slovenij

    Directory of Open Access Journals (Sweden)

    Sam Brooks

    2003-01-01

    Full Text Available Through a detailed view of STM and business journals available in Slovenia, this article depicts the value of particular databases and the impact of a tremendous influx of information into the country in recent years. The two most comprehensive databases that are available from EBSCO, the world’s largest intermediary between publishers and libraries, are explored. EBSCO’s company strategies with regard to its academic databases are described. The article examines which databases are strongest in each discipline,and covers issues such as the availability of journals most-cited, full text formats,peer-review status, embargo periods, backfiles, and other important facets.

  16. Peningkatan Mutu Lulusan STM melalui Pendidikan Sistem Ganda

    Directory of Open Access Journals (Sweden)

    Moedjiarto Moedjiarto

    2016-02-01

    Full Text Available This study was aimed at knowing the job skill practices (PKL managed by the Secondary Schools of Technology (STM in cooperation with PT PAL Indonesia and BLPT Surabaya based on the dual system of education. The population was students of STM Perkapalan, STM Negeri Surabaya and Sidoarjo. Observations, tests, and document analysis were used in gathering data. It was found out that there was a high revevance between practical materials and job skills needed by the STM Students, and their final achievement in the job skill practices (PKL was relatively good

  17. Oxygen adsorption on the Al₉Co₂(001) surface: first-principles and STM study.

    Science.gov (United States)

    Villaseca, S Alarcón; Loli, L N Serkovic; Ledieu, J; Fournée, V; Gille, P; Dubois, J-M; Gaudry, E

    2013-09-04

    Atomic oxygen adsorption on a pure aluminum terminated Al9Co2(001) surface is studied by first-principle calculations coupled with STM measurements. Relative adsorption energies of oxygen atoms have been calculated on different surface sites along with the associated STM images. The local electronic structure of the most favourable adsorption site is described. The preferential adsorption site is identified as a 'bridge' type site between the cluster entities exposed at the (001) surface termination. The Al-O bonding between the adsorbate and the substrate presents a covalent character, with s-p hybridization occurring between the states of the adsorbed oxygen atom and the aluminum atoms of the surface. The simulated STM image of the preferential adsorption site is in agreement with experimental observations. This work shows that oxygen adsorption generates important atomic relaxations of the topmost surface layer and that sub-surface cobalt atoms strongly influence the values of the adsorption energies. The calculated Al-O distances are in agreement with those reported in Al2O and Al2O3 oxides and for oxygen adsorption on Al(111).

  18. Deterministic Single Atom STM Tip Technology for Atomically Precise Manufacturing

    Science.gov (United States)

    Ballard, Joshua; Alexander, Justin; Radocea, Adrian; Bischof, Maia; Jaeger, David; Randall, John; Gorman, Brian; von Ehr, Jim; Reidy, Rick

    2011-03-01

    Deterministic tip fabrication for Scanning Tunneling Microscopy (STM) has long been an elusive goal, where the primary method of tip preparation usually includes significant ``tip conditioning'' once the tip has been incorporated into the STM. We have developed a process for generating reproducible single atom tips (SATs) with a small radius of curvature (r.o.c.) of less than 10nm. First, W(111) or W(110) tips are sputter sharpened using a self-limiting process to yield with r.o.c. of SAT is formed. Transmission Electron Microscopy is used to verify that after field evaporation the r.o.c. remains small. Correlations between FIM and tip performance in STM are determined, and long term STM stability is discussed.

  19. Single-layer ZnS supported on Au(111): A combined XPS, LEED, STM and DFT study

    Science.gov (United States)

    Deng, Xingyi; Sorescu, Dan C.; Lee, Junseok

    2017-04-01

    Single-layer of ZnS, consisting of one atomic layer of ZnS(111) plane, has been grown on Au(111) and characterized using X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). While the LEED measurement indicates a coincidence structure of ZnS-(3×3)/Au(111)-(4×4), high resolution STM images reveal hexagonal unit cells of 6.7×6.7 Å2 and 11.6×11.6 Å2, corresponding to √3 and 3 times the unit cell of the ideal zincblende ZnS-(1×1), respectively, depending on the tunneling conditions. Calculations based on density functional theory (DFT) indicate a significantly reconstructed non-planar structure of ZnS single-layer on Au(111) with 2/3 of the S anions being located nearly in the plane of the Zn cations and the rest 1/3 of the S anions protruding above the Zn plane. The calculated STM image shows similar characteristics to those of the experimental STM image. Additionally, the DFT calculations reveal the different bonding nature of the S anions in ZnS single-layer supported on Au(111).

  20. Body Dissatisfaction Revisited: On the Importance of Implicit Beliefs about Actual and Ideal Body Image

    National Research Council Canada - National Science Library

    Niclas Heider; Adriaan Spruyt; Jan De Houwer

    2018-01-01

    ...) and the desired ideal state of the body (i.e., ideal body image). We assessed implicit beliefs about these two aspects of the body image independently using two Relational Responding Tasks (RRT...

  1. Prototyping the HPDP Chip on STM 65 NM Process

    Science.gov (United States)

    Papadas, C.; Dramitinos, G.; Syed, M.; Helfers, T.; Dedes, G.; Schoellkopf, J.-P.; Dugoujon, L.

    2011-08-01

    Currently Astrium GmbH is involved in the of the High Performance Data Processor (HPDP) development programme for telecommunication applications under a DLR contract. The HPDP project targets the implementation of the commercially available reconfigurable array processor IP (XPP from the company PACT XPP Technologies) in a radiation hardened technology.In the current complementary development phase funded under the Greek Industry Incentive scheme, it is planned to prototype the HPDP chip in commercial STM 65 nm technology. In addition it is also planned to utilise the preliminary radiation hardened components of this library wherever possible.This abstract gives an overview of the HPDP chip architecture, the basic details of the STM 65 nm process and the design flow foreseen for the prototyping. The paper will discuss the development and integration issues involved in using the STM 65 nm process (also including the available preliminary radiation hardened components) for designs targeted to be used in space applications.

  2. Revisiting renovascular imaging for renal sympathetic denervation: current techniques and applications

    Energy Technology Data Exchange (ETDEWEB)

    Pua, Uei; Tan, Cher Heng [Tan Tock Seng Hospital, Department of Diagnostic Radiology, Singapore (Singapore); Ho, Hee Hwa; Tan, Julian Ko Beng; Ong, Paul Jau Leong [Tan Tock Seng Hospital, Department of Cardiology, Singapore (Singapore)

    2014-08-28

    Renal sympathetic denervation (RDN) is an emerging technique in the treatment of resistant hypertension, most commonly performed using an endovascular approach. Clinical and anatomical criteria for RDN are well established and imaging plays an integral role in selecting patients with suitable anatomy, procedural planning and device selection. Nevertheless, the current body of literature surrounding imaging related to RDN remains limited. The purpose of this article is to illustrate the expectations and limitations of various imaging techniques, including Doppler ultrasound, CT angiography, MR angiography and newer techniques such as non-contrast MR angiography, in the context of RDN. (orig.)

  3. Electronic properties of precious-metal coated W tips in STM: Role of spin-orbit coupling

    Science.gov (United States)

    Yamashita, T.; Akiyama, T.; Nakamura, K.; Ito, T.; Rhim, S. H.; Freeman, A. J.

    2013-03-01

    Scanning tunneling microscopy (STM) has proved a versatile tool invigorating many physics at an atomic scale, where chemical identity and shape of the probe tip greatly affect resolution and sensitivity. There have been many efforts to functionalize STM tips: coating W tips with organic molecules and 3d transition metals, which facilitate the selective imaging with enhanced tunneling current. In this work, we model W(110) tips coated by precious metals such as Au, Ag, and Pt, in which large spin-orbit coupling significantly influences the electronic structure of the STM probe. Furthermore, we argue that this spin-orbit coupling can be used as a spin detecting STM probe without additional bias switching. The stability of the W(110) apex atom for each metal coating is also discussed. Supported at N. U. by the DOE (DE-FG02-05ER45372), and at Mie U. by the Young Researcher Overseas Visits Program for Vitalizing Brain Circulation (R2214) from the Japan Society for the Promotion of Science.

  4. Design of Electronic Clock based on STM32

    Science.gov (United States)

    Huang, Jian

    2017-09-01

    This paper describes the design method of electronic clock based on STM32. The hardware circuit is designed, which uses the built-in RTC module of the STM32, and the backup battery is used to supply power. When first programming, the current date and time is wrote, after that the RTC module will automatically count. It also can be used to set the alarm time. Software programming can read the current time and conversion it, then it will be displayed on the LCD screen. The test results show that the design has the advantages of accurate timing, high reliability and long service life.

  5. Electrochemical etching of sharp tips for STM reveals singularity

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Oddershede, Lene

    2002-01-01

    Electrochemical etching of metal wires is widely used to produce atomically sharp tips for use in scanning tunneling microscopy (STM). In this letter we uncover the existence of a finite-time singularity in the process: Several of the physical parameters describing the system exhibit scaling...... towards and away from a particular singular point in time, exactly the time at which the wire breaks. The obtained scaling exponents coincide with exponents reported from other singular dynamical systems. The results also provide knowledge of how to control STM tip properties on the nano-scale....

  6. Body Dissatisfaction Revisited: On the Importance of Implicit Beliefs about Actual and Ideal Body Image

    Directory of Open Access Journals (Sweden)

    Niclas Heider

    2018-01-01

    Full Text Available Body dissatisfaction (i.e., a negative attitude towards one’s own physical appearance is assumed to originate from a perceived discrepancy between the actual physical appearance (i.e., actual body image and the desired ideal state of the body (i.e., ideal body image. We assessed implicit beliefs about these two aspects of the body image independently using two Relational Responding Tasks (RRT in a sample of participants who were either low or high in explicitly reported body dissatisfaction. As hypothesized, differences in body dissatisfaction exerted a differential influence on the two RRT scores. The implicit belief that one is thin was less pronounced in participants who were strongly dissatisfied with their body relative to participants who were more satisfied with their body. The implicit desire to be thin (i.e., thin ideal body image, in contrast, tended to be more pronounced in participants who exhibited a high degree of body dissatisfaction as compared to participants who exhibited a low degree of body dissatisfaction. Hierarchical regression analyses also revealed that the RRT scores were predictive of self-reported body dissatisfaction, even over and above the predictive validity of some (but not all explicit predictors of body dissatisfaction that were included in the present study. More generally, these findings contribute to the empirical validation of the RRT as a measure of implicit beliefs in the context of body dissatisfaction.

  7. How additives affect Cu electrodeposition : an electrochemical STM study

    NARCIS (Netherlands)

    Yanson, Yuriy Igorevich

    2012-01-01

    A study of the effect of chloride and sulfate anions, as well as of SPS molecules on Cu electrodeposition is presented in this thesis. The deposition process was analyzed by means of a home-built fast electrochemical STM in situ after and during deposition.

  8. Reverse Redistribution in Myocardial Perfusion Imaging: Revisited with 64-slice MDCT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min Kyung; Kim, Jeong Ho; Hwang, Kyung Hoon; Choi, In Suck; Choi, Soo Jin; Choe, Won Sick [Gachon University Gil Hospital, Incheon (Korea, Republic of); Yoon, Min Ki [Good Samaritan Hospital, Pohang (Korea, Republic of)

    2010-06-15

    The authors report myocardial perfusion imaging of a patient showing reverse redistribution (RR) and a 64-slice multidetector-row computed tomography (MDCT) with corresponding findings. The patient had subendocardial myocardial infarction (MI) with positive electrocardiogram (EMG) findings and elevated levels of cardiac isoenzymes. Experiencing this case emphasizes the importance of complementary correlation of a new diagnostic modality that helps us to understand the nature of RR.

  9. Van Wyk and Grumbach syndrome revisited: imaging and clinical findings in pre- and postpubertal girls

    Energy Technology Data Exchange (ETDEWEB)

    Browne, Lorna P.; Guillerman, R.P. [Texas Children' s Hospital, Department of Diagnostic Imaging, Houston, TX (United States); Boswell, Hillary B. [Texas Children' s Hospital, Department of Gynecology, Houston, TX (United States); Crotty, Eric J.; O' Hara, Sara M.; Birkemeier, Krista L. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2008-05-15

    In 1960 Van Wyk and Grumbach described a syndrome of juvenile hypothyroidism, precocious puberty and ovarian enlargement. These findings undergo complete regression with thyroid hormone replacement therapy. This diagnosis can be made on the basis of imaging findings and thyroid function analysis, avoiding surgery. To relate the distinctive clinical and imaging features and putative pathophysiological mechanism of a series of patients with Van Wyk and Grumbach syndrome (VWGS). Patients with VWGS diagnosed at two large children's hospitals over a 6-year period beginning in 1999 were retrospectively reviewed. A literature review was also conducted. Five female patients were diagnosed with cystic ovarian enlargement and hypothyroidism at ages ranging from 9 to 17 years. Isosexual precocious puberty was found in prepubescent patients. Associated findings included delayed bone age, ascites, and pleural and pericardial effusions. Ovarian cyst involution occurred following treatment of the hypothyroidism. The association of primary hypothyroidism with cystic ovarian enlargement and precocious puberty is important to recognize. In the absence of suspected ovarian torsion, surgery is unnecessary, as cyst regression occurs after appropriate thyroid hormone replacement. Noncompliance with hormone replacement therapy should be considered when cystic ovarian enlargement is noted in patients with a history of hypothyroidism. (orig.)

  10. {sup 18}F-FDOPA PET/CT imaging of insulinoma revisited

    Energy Technology Data Exchange (ETDEWEB)

    Imperiale, Alessio; Namer, Izzie-Jacques [University Hospitals of Strasbourg, Department of Biophysics and Nuclear Medicine, Strasbourg (France); University of Strasbourg/CNRS and FMTS, Faculty of Medicine, ICube - UMR 7357, Strasbourg (France); Sebag, Frederic [Aix-Marseille University, Department of Endocrine Surgery, La Timone University Hospital, Marseille (France); Vix, Michel [University of Strasbourg, Department of General, Digestive, and Endocrine Surgery, IRCAD-IHU, Strasbourg (France); Castinetti, Frederic [Aix-Marseille University, Department of Endocrinology, Diabetes and Metabolic Disorders, La Timone University Hospital, Marseille (France); Kessler, Laurence; Moreau, Francois [University of Strasbourg, Department of Diabetology, University Hospital of Strasbourg, Strasbourg (France); Bachellier, Philippe [University Hospitals of Strasbourg, Department of Visceral Surgery and Transplantation, Strasbourg (France); Guillet, Benjamin; Mundler, Olivier [Aix-Marseille University, Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Marseille (France); Taieb, David [Aix-Marseille University, Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Marseille (France); Aix-Marseille University, Biophysics and Nuclear Medecine, La Timone University Hospital, European Center for Research in Medical Imaging, Marseille (France)

    2014-11-01

    {sup 18}F-FDOPA PET imaging is increasingly used in the work-up of patients with neuroendocrine tumours. It has been shown to be of limited value in localizing pancreatic insulin-secreting tumours in adults with hyperinsulinaemic hypoglycaemia (HH) mainly due to {sup 18}F-FDOPA uptake by the whole pancreatic gland. The objective of this study was to review our experience with {sup 18}F-FDOPA PET/CT imaging with carbidopa (CD) premedication in patients with HH in comparison with PET/CT studies performed without CD premedication in an independent population. A retrospective study including 16 HH patients who were investigated between January 2011 and December 2013 using {sup 18}F-FDOPA PET/CT (17 examinations) in two academic endocrine tumour centres was conducted. All PET/CT examinations were performed under CD premedication (200 mg orally, 1 - 2 h prior to tracer injection). The PET/CT acquisition protocol included an early acquisition (5 min after {sup 18}F-FDOPA injection) centred over the upper abdomen and a delayed whole-body acquisition starting 20 - 30 min later. An independent series of eight consecutive patients with HH and investigated before 2011 were considered for comparison. All patients had a reference whole-body PET/CT scan performed about 1 h after {sup 18}F-FDOPA injection. In all cases, PET/CT was performed without CD premedication. In the study group, {sup 18}F-FDOPA PET/CT with CD premedication was positive in 8 out of 11 patients with histologically proven insulinoma (73 %). All {sup 18}F-FDOPA PET/CT-avid insulinomas were detected on early images and 5 of 11 (45 %) on delayed ones. The tumour/normal pancreas uptake ratio was not significantly different between early and delayed acquisitions. Considering all patients with HH, including those without imaging evidence of disease, the detection rate of the primary lesions using CD-assisted {sup 18}F-FDOPA PET/CT was 53 %, showing 9 insulinomas in 17 studies performed. In the control group (without

  11. Atomic resolution images of graphite in air

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, D.A.; Shedd, G.M.; Griffis, D.; Russell, P.E.

    1988-12-01

    One sample used for proof of operation for atomic resolution in STM is highly oriented pyrolytic graphite (HOPG). This sample has been imaged with many different STM`s obtaining similar results. Atomic resolution images of HOPG have now been obtained using an STM designed and built at the Precision Engineering Center. This paper discusses the theoretical predictions and experimental results obtained in imaging of HOPG.

  12. Fullerenes Revisited

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 2. Fullerenes Revisited: Materials Chemistry and Applications of C60 Molecules. Pradeep P Shanbogh Nalini G Sundaram. General Article Volume 20 Issue 2 February 2015 pp 123-135 ...

  13. The Big Five of Personality and structural imaging revisited: a VBM - DARTEL study.

    Science.gov (United States)

    Liu, Wei-Yin; Weber, Bernd; Reuter, Martin; Markett, Sebastian; Chu, Woei-Chyn; Montag, Christian

    2013-05-08

    The present study focuses on the neurostructural foundations of the human personality. In a large sample of 227 healthy human individuals (168 women and 59 men), we used MRI to examine the relationship between personality traits and both regional gray and white matter volume, while controlling for age and sex. Personality was assessed using the German version of the NEO Five-Factor Inventory that measures individual differences in the 'Big Five of Personality': extraversion, neuroticism, agreeableness, conscientiousness, and openness to experience. In contrast to most previous studies on neural correlates of the Big Five, we used improved processing strategies: white and gray matter were independently assessed by segmentation steps before data analysis. In addition, customized sex-specific diffeomorphic anatomical registration using exponentiated lie algebra templates were used. Our results did not show significant correlations between any dimension of the Big Five and regional gray matter volume. However, among others, higher conscientiousness scores correlated significantly with reductions in regional white matter volume in different brain areas, including the right insula, putamen, caudate, and left fusiformis. These correlations were driven by the female subsample. The present study suggests that many results from the literature on the neurostructural basis of personality should be reviewed carefully, considering the results when the sample size is larger, imaging methods are rigorously applied, and sex-related and age-related effects are controlled.

  14. Temporomandibular joint (TMJ) pain revisited with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

    Science.gov (United States)

    Tasali, N; Cubuk, R; Aricak, M; Ozarar, M; Saydam, B; Nur, H; Tuncbilek, N

    2012-03-01

    We aimed to assess the contrast enhancement patterns of the retrodiscal tissue with dynamic contrast-enhanced MR imaging (DCE-MRI) with respect to different temporomandibular joint disc pathologies. Additionally, we questioned the relationship between the temporomandibular joint (TMJ) pain and the contrast enhancement pattern of the retrodiscal tissue regardless of the TMJ disc position. 52 joints of 26 patients (4 males and 22 females) who have pain in at least at one of their TMJ were included in this study. For the qualitative analysis, the joints were divided into four groups in terms of their disc positions: normal (1), partially displaced with or without reduction (2), totally dislocated with reduction (3) and totally dislocated without reduction (4). Besides, two different joint groups were constituted, namely the painful group and painless group according to the clinical findings without taking the TMJ disc positions into account. Quantitative analyses were made by means of measuring signal intensity ratios (SI) ratio at the retrodiscal tissue (from internal side and external side of the each joint) using DCE-MRI and these measurements were analyzed with paired samples t test to define the difference between the measurements. At the second stage, the time-dependent arithmetical mean values of the SI ratios were calculated for each joint group and significant differences between the groups were questioned using analysis of variance (ANOVA) test. Besides, painful and painless groups which were classified on the basis of the clinical data were compared according to the mean SI ratios found for each joint and the significant differences between these two groups were assessed by means of Student's T test. The results were assessed in 95% confidence interval where the significance level was pjoints with partial displacement. Another significant difference was found between the average time versus SI ratio curves of the four groups. In consequence of the

  15. Creativity and positive symptoms in schizophrenia revisited: Structural connectivity analysis with diffusion tensor imaging.

    Science.gov (United States)

    Son, Shuraku; Kubota, Manabu; Miyata, Jun; Fukuyama, Hidenao; Aso, Toshihiko; Urayama, Shin-ichi; Murai, Toshiya; Takahashi, Hidehiko

    2015-05-01

    Both creativity and schizotypy are suggested to be manifestations of the hyperactivation of unusual or remote concepts/words. However, the results of studies on creativity in schizophrenia are diverse, possibly due to the multifaceted aspects of creativity and difficulties of differentiating adaptive creativity from pathological schizotypy/positive symptoms. To date, there have been no detailed studies comprehensively investigating creativity, positive symptoms including delusions, and their neural bases in schizophrenia. In this study, we investigated 43 schizophrenia and 36 healthy participants using diffusion tensor imaging. We used idea, design, and verbal (semantic and phonological) fluency tests as creativity scores and Peters Delusions Inventory as delusion scores. Subsequently, we investigated group differences in every psychological score, correlations between fluency and delusions, and relationships between these scores and white matter integrity using tract-based spatial statistics (TBSS). In schizophrenia, idea and verbal fluency were significantly lower in general, and delusion score was higher than in healthy controls, whereas there were no group differences in design fluency. We also found positive correlation between phonological fluency and delusions in schizophrenia. By correlation analyses using TBSS, we found that the anterior part of corpus callosum was the substantially overlapped area, negatively correlated with both phonological fluency and delusion severity. Our results suggest that the anterior interhemispheric dysconnectivity might be associated with executive dysfunction, and disinhibited automatic spreading activation in the semantic network was manifested as uncontrollable phonological fluency or delusions. This dysconnectivity could be one possible neural basis that differentiates pathological positive symptoms from adaptive creativity. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Structures of a CO adlayer on a Pt(100) electrode in HClO4 solution studied by in situ STM.

    Science.gov (United States)

    Wakisaka, Mitsuru; Ohkanda, Takaharu; Yoneyama, Toshiki; Uchida, Hiroyuki; Watanabe, Masahiro

    2005-06-07

    We have obtained the first in situ STM atomic images of a CO adlayer on a Pt(100)-(1 x 1) electrode in 0.1 M HClO(4) solution, exhibiting a phase transition from c(6 x 2)-10CO to c(4 x 2)-6CO at E > 0.3 V vs. RHE.

  17. NSS5/SP-STM2 Joint International Conference

    Energy Technology Data Exchange (ETDEWEB)

    Saw-Wai Hla

    2009-05-03

    The NSS5/SP-STM2 conference was held in Athens, Ohio July 15-19, 2008. The conference brought together a prestigious group of scientists from all over the globe to focus for 3 ½ days on a variety of nanoscience topics, particularly on nanoscale spectroscopy and spin-polarized scanning tunneling microscopy. The conference was attended by many young scientists as well as senior scientists. Attendees to the conference were drawn from more than 10 countries and included 28 invited speakers, who are the leading scientists in their respective research areas. Included among the invited speakers were 4 plenary speakers - eminent scientists in their fields. The conference was divided into two parallel sessions – the NSS5 session and the SP-STM2 session.

  18. Measurement of chirality of charge-density-waves in TiSe{sub 2} by using STM

    Energy Technology Data Exchange (ETDEWEB)

    Ishioka, J. [Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Hokkaido (Japan); Liu, Y.H. [Department of Physics and Astronomy, Clippinger Lab 251B, Athens, OH 45701 (United States); Shimatake, K. [Intellectual Property Headquarters, Nikon Corporation, 1-6-3, Nishi-ohi, Shinagawa-ku, Tokyo (Japan); Kurosawa, T. [Department of Physics, Hokkaido University, Sapporo 060-0810, Hokkaido (Japan); Ichimura, K.; Toda, Y. [Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Hokkaido (Japan); Oda, M. [Department of Physics, Hokkaido University, Sapporo 060-0810, Hokkaido (Japan); Tanda, S., E-mail: tanda@eng.hokudai.ac.j [Department of Applied Physics, Hokkaido University, Sapporo 060-8628, Hokkaido (Japan)

    2010-06-01

    We report the chirality of charge density waves (CDW) in 1T-TiSe{sub 2} by using scanning tunneling microscopy (STM) measurements. We found that the CDW intensity becomes Ia{sub 1}:Ia{sub 2}:Ia{sub 3}=1:0.7{+-}0.1:0.5{+-}0.1, where Ia{sub i} (i=1, 2, 3) is the amplitude of the tunneling current contributed by the CDWs. We found two states, in which the three intensity peaks of the CDW decrease clockwise and anticlockwise when we index each nesting vector in order of intensity in the Fourier transformation of the STM images. We found that this difference arises from CDW stacking along the c-axis at intervals of 2c{sub 0}/3. This chirality is attributed to the helical stacking such as cholesteric liquid crystals.

  19. Sensemaking Revisited

    DEFF Research Database (Denmark)

    Holt, Robin; Cornelissen, Joep

    2014-01-01

    We critique and extend theory on organizational sensemaking around three themes. First, we investigate sense arising non-productively and so beyond any instrumental relationship with things; second, we consider how sense is experienced through mood as well as our cognitive skills of manipulation...... research by revisiting Weick’s seminal reading of Norman Maclean’s book surrounding the tragic events of a 1949 forest fire at Mann Gulch, USA....

  20. Revisiting and Renegotiating Wars

    DEFF Research Database (Denmark)

    Gade, Solveig

    2014-01-01

    Anri Sala’s film 1395 Days Without Red (2011) provides a kind of reenactment of an accidental day during the 1992-95 siege of Sarajevo. Shot in today’s Sarajevo, the film revisits and embodies some of the widely circulated images of the siege, such as inhabitants sprinting across so-called Sniper...... Alley in order to avoid the bullets of the Bosnian Serbian snipers positioned around the city. Based on a close reading of Sala’s work, this article will scrutinize how subjectivating techniques of power, during times of war, affectively work to create boundaries between those excluded from and those...

  1. Physical Modeling of Contact Processes on the Cutting Tools Surfaces of STM When Turning

    Science.gov (United States)

    Belozerov, V. A.; Uteshev, M. H.

    2016-08-01

    This article describes how to create an optimization model of the process of fine turning of superalloys and steel tools from STM on CNC machines, flexible manufacturing units (GPM), machining centers. Creation of the optimization model allows you to link (unite) contact processes simultaneously on the front and back surfaces of the tool from STM to manage contact processes and the dynamic strength of the cutting tool at the top of the STM. Established optimization model of management of the dynamic strength of the incisors of the STM in the process of fine turning is based on a previously developed thermomechanical (physical, heat) model, which allows the system thermomechanical approach to choosing brands STM (domestic and foreign) for cutting tools from STM designed for fine turning of heat resistant alloys and steels.

  2. Dependence of electric field on STM tip preparation

    DEFF Research Database (Denmark)

    Huang, D.H.; Grey, Francois; Aono, M.

    1998-01-01

    Voltage pulses applied between an STM tip and a surface can modify the surface on the nanometer scale due to electric-field-induced evaporation. However, at present, different groups have achieved surface modification with quite different bias conditions, and it is still difficult to obtain high...... reproducibility in such experiments. In this paper, we measure the tip displacement during a pulse at constant tunnelling current, and deduce that the electric field produced by the pulse depends in a systematic way on tip preparation, The results show how differences in tip preparation can be a major source...

  3. Diffusion of anthracene derivatives on Cu(111) studied by STM and DFT

    Science.gov (United States)

    Wyrick, Jonathan; Bartels, Ludwig; Einstein, Theodore

    2014-03-01

    Substituted anthracenes have drawn attention due to their ability to diffuse uniaxially on a Cu(111) surface. We compare anthracene to three of its derivatives whose 9,10 hydrogens are replaced by elements of the chalcogen group that act as linkers binding the molecules to a Cu(111) substrate. DFT calculations shed light on STM imaging and diffusion studies on the three substituted species. We present an analysis of the DFT results in which energetic contributions to the diffusion barriers are partitioned among the Kohn-Sham orbitals, allowing us to make assignments as to how each orbital affects diffusion for each species and draw comparisons between them. Present address: Center for Nanoscale Science and Technology, NIST, Gaithersburg, MD.

  4. Two-probe STM experiments at the atomic level.

    Science.gov (United States)

    Kolmer, Marek; Olszowski, Piotr; Zuzak, Rafal; Godlewski, Szymon; Joachim, Christian; Szymonski, Marek

    2017-11-08

    Direct characterization of planar atomic or molecular scale devices and circuits on a supporting surface by multi-probe measurements requires unprecedented stability of single atom contacts and manipulation of scanning probes over large, nanometer scale area with atomic precision. In this work, we describe the full methodology behind atomically defined two-probe scanning tunneling microscopy (STM) experiments performed on a model system: dangling bond dimer wire supported on a hydrogenated germanium (0 0 1) surface. We show that 70 nm long atomic wire can be simultaneously approached by two independent STM scanners with exact probe to probe distance reaching down to 30 nm. This allows direct wire characterization by two-probe I-V characteristics at distances below 50 nm. Our technical results presented in this work open a new area for multi-probe research, which can be now performed with precision so far accessible only by single-probe scanning probe microscopy (SPM) experiments.

  5. Two-probe STM experiments at the atomic level

    Science.gov (United States)

    Kolmer, Marek; Olszowski, Piotr; Zuzak, Rafal; Godlewski, Szymon; Joachim, Christian; Szymonski, Marek

    2017-11-01

    Direct characterization of planar atomic or molecular scale devices and circuits on a supporting surface by multi-probe measurements requires unprecedented stability of single atom contacts and manipulation of scanning probes over large, nanometer scale area with atomic precision. In this work, we describe the full methodology behind atomically defined two-probe scanning tunneling microscopy (STM) experiments performed on a model system: dangling bond dimer wire supported on a hydrogenated germanium (0 0 1) surface. We show that 70 nm long atomic wire can be simultaneously approached by two independent STM scanners with exact probe to probe distance reaching down to 30 nm. This allows direct wire characterization by two-probe I-V characteristics at distances below 50 nm. Our technical results presented in this work open a new area for multi-probe research, which can be now performed with precision so far accessible only by single-probe scanning probe microscopy (SPM) experiments.

  6. Leed and STM Study of cs on Cu(211)

    Science.gov (United States)

    Caragiu, M.; Seyller, Tl.; Diehl, R. D.; Norris, A. G.; McGrath, R.; Muryn, C. A.

    A low-temperature (25 K) STM study of Cs adsorption on Cu(211) indicates that Cs forms variable-density structures which align along the step edges of the Cu(211) surface. The density of the overlayer increases with Cs coverage, forming a quasihexagonal c(2×2) structure at a coverage of 0.17. A dynamical LEED study of that structure at 130 K indicates that the Cs atoms are adsorbed on top of the Cu atoms in the center of the terraces, with a Cs-Cu nearest-neighbor distance of 3.56± 0.04 Å. This structure is accompanied by a significant rumpling of the Cu(211) surface.

  7. Synthesis, electrochemistry, STM investigation of oligothiophene self-assemblies with superior structural order and electronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Cheng-Yu [C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Liu, Yinghao; Yarotski, Dmitry [Center of Integrated Nanotechnologies, Materials Physics and Application Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Li, Hao [Theory Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Xu, Ping; Yen, Hung-Ju [C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Tretiak, Sergei, E-mail: serg@lanl.gov [Theory Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Wang, Hsing-Lin, E-mail: hwang@lanl.gov [C-PCS, Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2016-12-20

    Graphical abstract: STM imaging reveals differently oriented domains of self-assembled tetrathiophene molecules. - Highlights: • Optical and redox properties of oligothiophene derivatives are studied. • Packing pattern of self-assembly monolayer depends on the conjugation length. • Strong electronic coupling and three redox couples in cyclic voltamogram are observed in the hierarchical self-assembly. - Abstract: Three oligothiophene (terthiophene, tetrathiophene and pentathiophene) derivatives are synthesized and their monolayer self-assemblies on gold (Au) are prepared via Au–S covalent bond. Our UV–Vis experimental characterization of solution reveals the dependence of the optical properties on the conjugation length of the oligothiophenes, which compares well with Time-Dependent Density Functional Theory (TDDFT) simulations of spectra of individual chromophores. Photoluminescent spectra of thin films show pronounced red shifts compared to that of solutions, suggesting strong inter-oligomer interactions. The comparative studies of cyclic voltammograms of tetrathiophene from solution, cast film and self-assembled monolayer (SAM) indicate presence of one, two, and three oxidized species in these samples, respectively, suggesting a very strong electronic coupling between tetrathiophene molecules in the SAM. Scanning tunneling microscopy (STM) imaging of SAMs of the tetrathiophene on an atomically flat Au surface exhibits formation of monolayer assemblies with molecular order, and the molecular packing appears to show an overlay of oligothiophene molecules on top of another one. In contrast, the trimer and pentamer images show only aggregated species lacking long-range order on the molecular level. Such trends in going from disordered–ordered–disordered monolayer assemblies are mainly due to a delicate balance between inter-chromophore π–π couplings, hydrophobic interaction and the propensity to form Au–S covalent bond. Such hypothesis has been

  8. Direct observation of conformational changes of beta-substituted duodecithiophene on a Au(111)-(square root(3) x 22) substrate using in situ electrochemical STM in 0.1 M HClO4.

    Science.gov (United States)

    Tongol, Bernard John V; Wang, Li; Yau, Shueh-Lin; Otsubo, Tetsuo; Itaya, Kingo

    2010-01-19

    The adsorption of hexahexylduodecithiophene (12T) on a Au(111) electrode was investigated by using cyclic voltammetry (CV) and in situ electrochemical scanning tunneling microscopy (EC-STM) in 0.10 M HClO(4). Potential control at 0.20 V (vs RHE) revealed adlayer structures of mostly folded and rarely angular (oblique) and extended conformations on a reconstructed Au(111)-(square root(3) x 22) surface. The angular and extended conformations predominate when the electrode potential is increased to 0.35 and 0.60 V. Folded structures are still evident, but dynamic STM studies showed unfolding of this conformation. With molecular STM imaging of 12T adlayers, we address the packing arrangement and conformational changes of 12T admolecules on the reconstructed Au(111) electrode surface.

  9. Characterization of tungsten tips for STM by SEM/AES/XPS

    NARCIS (Netherlands)

    Lisowski, W.F.; van den Berg, A.H.J.; Kip, Gerhardus A.M.; Hanekamp, L.J.; Hanekamp, L.J.

    1991-01-01

    For the first time, both X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES) techniques were applied in analysis of surface contamination of electrochemically etched Scanning Tunneling Microscope (STM) tungsten tips. Carbon monoxide, graphite, tungsten carbide and tungsten

  10. Design of wireless video transmission system based on STM32 microcontroller

    Science.gov (United States)

    Yang, Fan; Ma, Chunting; Li, Haoyi

    2017-03-01

    The design of a wireless video transmission system based on STM32, the system uses the STM32F103VET6 microprocessor as the core, through the video acquisition module collects video data, video data will be sent to the receiver through the wireless transmitting module, receiving data will be displayed on the LCD screen. The software design process of receiver and transmitter is introduced. The experiment proves that the system realizes wireless video transmission function.

  11. Hydrogen absorption in epitaxial Nb-films. A STM-study; Wasserstoffabsorption in epitaktischen Niobschichten. Eine STM-Studie

    Energy Technology Data Exchange (ETDEWEB)

    Noerthemann, K.

    2006-07-01

    In this work the phase transition of the system Niobium Hydrogen in thin films was investigated. The epitaxial Niobium films were fabricated using ion sputtering on sapphire substrates. The changes due to the hydrogen loading were observed with the scanning tunnel microscope (STM). With this method it is possible to detect the changes in the nanometer scale. With help of theoretical models it was possible to establish volume changes through the measured surface data. This is possible due to the linear relationship between hydrogen concentration and volume expansion. Comparisons between experimental data and calculations, which were done using the 'finite element method', allows to establish that the hydride precipitates are of cylindrical form. Thereafter the time continuously measurements of nuclei formation and precipitations growth was investigated. The growth is described through a 'Johnson-Mehl-Avrami' kinetic. Whereas coherent precipitations at first stage were observed, afterwards at higher Hydrogen concentration these transformed to incoherent. This coherent - incoherent transition occur at precipitation sizes which shows a film thickness dependency. (orig.)

  12. In Situ Studies of Surface Mobility on Noble Metal Model Catalysts Using STM and XPS at Ambient Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, Derek Robert [Univ. of California, Berkeley, CA (United States)

    2010-06-01

    High Pressure Scanning Tunneling Microscopy (HP-STM) and Ambient Pressure X-ray Photoelectron Spectroscopy were used to study the structural properties and catalytic behavior of noble metal surfaces at high pressure. HP-STM was used to study the structural rearrangement of the top most atomic surface layer of the metal surfaces in response to changes in gas pressure and reactive conditions. AP-XPS was applied to single crystal and nanoparticle systems to monitor changes in the chemical composition of the surface layer in response to changing gas conditions. STM studies on the Pt(100) crystal face showed the lifting of the Pt(100)-hex surface reconstruction in the presence of CO, H2, and Benzene. The gas adsorption and subsequent charge transfer relieves the surface strain caused by the low coordination number of the (100) surface atoms allowing the formation of a (1 x 1) surface structure commensurate with the bulk terminated crystal structure. The surface phase change causes a transformation of the surface layer from hexagonal packing geometry to a four-fold symmetric surface which is rich in atomic defects. Lifting the hex reconstruction at room temperature resulted in a surface structure decorated with 2-3 nm Pt adatom islands with a high density of step edge sites. Annealing the surface at a modest temperature (150 C) in the presence of a high pressure of CO or H2 increased the surface diffusion of the Pt atoms causing the adatom islands to aggregate reducing the surface concentration of low coordination defect sites. Ethylene hydrogenation was studied on the Pt(100) surface using HP-STM. At low pressure, the lifting of the hex reconstruction was observed in the STM images. Increasing the ethylene pressure to 1 Torr, was found to regenerate the hexagonally symmetric reconstructed phase. At room temperature ethylene undergoes a structural rearrangement to form ethylidyne. Ethylidyne preferentially binds at the three-fold hollow sites, which

  13. Dithiocarbamate-protected ruthenium nanoparticles: Synthesis, spectroscopy, electrochemistry and STM studies

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wei; Ghosh, Debraj; Sun Jia; Tong, Moony C.; Deng Fengjun [Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Chen Shaowei [Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)], E-mail: schen@chemistry.ucsc.edu

    2007-12-20

    Stable ruthenium nanoparticles were synthesized in a biphasic system with a protecting monolayer of dithiocarbamate derivatives. The core size of the resulting Ru particles was found to vary with the initial ligand-metal feed ratio. UV-vis spectroscopic measurements showed a Mie scattering profile, with no obvious surface-plasmon resonance. The size and crystal structures of the particles were characterized by transmission electron microscopic (TEM) measurements. A significant fraction of the nanoparticles was found within the size range of 2-4 nm in diameter and of spherical shape from the TEM measurements. Clear lattice fringes could be observed in high-resolution TEM images with the fringe spacing consistent with the Ru(1 0 1) lattice planes. Electrochemical studies of Ru particles with different core size exhibited the solution-phase quantized charging of the particle double layers, analogous to those reported for gold and other transition-metal particles. The potential spacing between adjacent quantized charging peaks was found to vary with the particle core size, corresponding to the variation of the particle molecular capacitance. These charge-transfer properties were very consistent with the STM measurements of isolated nanoparticles which exhibit clear Coulomb blockade and staircase features.

  14. Dithiocarbamate-protected ruthenium nanoparticles: Synthesis, spectroscopy, electrochemistry and STM studies

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei; Ghosh, Debraj; Sun, Jia; Tong, Moony C.; Deng, Fengjun; Chen, Shaowei [Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2007-12-20

    Stable ruthenium nanoparticles were synthesized in a biphasic system with a protecting monolayer of dithiocarbamate derivatives. The core size of the resulting Ru particles was found to vary with the initial ligand-metal feed ratio. UV-vis spectroscopic measurements showed a Mie scattering profile, with no obvious surface-plasmon resonance. The size and crystal structures of the particles were characterized by transmission electron microscopic (TEM) measurements. A significant fraction of the nanoparticles was found within the size range of 2-4 nm in diameter and of spherical shape from the TEM measurements. Clear lattice fringes could be observed in high-resolution TEM images with the fringe spacing consistent with the Ru(1 0 1) lattice planes. Electrochemical studies of Ru particles with different core size exhibited the solution-phase quantized charging of the particle double layers, analogous to those reported for gold and other transition-metal particles. The potential spacing between adjacent quantized charging peaks was found to vary with the particle core size, corresponding to the variation of the particle molecular capacitance. These charge-transfer properties were very consistent with the STM measurements of isolated nanoparticles which exhibit clear Coulomb blockade and staircase features. (author)

  15. Revisiting the Potential of Alternating Repetition Time Balanced Steady-State Free Precession Imaging of the Abdomen at 3 T.

    Science.gov (United States)

    Gurney-Champion, Oliver J; Nederveen, Aart J; Klaassen, Remy; Engelbrecht, Marc R; Bel, Arjan; van Laarhoven, Hanneke W M; Stoker, Jaap; Goncalves, Sonia I

    2016-09-01

    The aim was to investigate the value of optimized 3-dimensional alternating repetition time balanced steady-state free precession (ATR-SSFP), as an alternative to conventional segmented balanced steady-state free precession (bSSFP) with fat suppression prepulse (FS-bSSFP), in single breath-hold abdominal magnetic resonance imaging at 3 T. Bloch simulations were performed to determine the optimal flip angle (FA = 1-90 degrees) and τ (1-3) with respect to signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) between abdominal organs for ATR-SSFP. These were corroborated by phantom measurements for different T1/T2 values (5-47) as well as in a healthy volunteer. In addition, fat suppression efficiency was studied using phantom and volunteer measurements. The effect of resolution on image quality was studied in a healthy volunteer. Using the optimal settings, ATR-SSFP images as well as FS-bSSFP images were obtained in 15 pancreatic cancer patients. For 10 structures of interest, the signal ratio with respect to the pancreas was computed and compared between both sequences. Finally, 10 items on image quality (fat suppression, artifacts, and sharpness) and tissue conspicuity (ducts, vessels, and duodenum) were scored by 2 abdominal radiologists for both image sequences. The results of simulations, phantom measurements, and volunteer measurements showed that, considering scan time, fat suppression, and clinical relevance, the ideal settings for ATR-SSFP were as follows: τ = 3; TR1 = 3.46 milliseconds; radiofrequency phase cycling 0, 180, 180, 0 degrees; and FA = 13-16 degrees (highest SNR) and 24-26 degrees (highest CNR). The optimized feasible additional settings implemented for patient scans were FA = 18 degrees and resolution = 1.4 × 1.4 × 1.4 mm. In patients, the signal ratios of both ATR-SSFP and FS-bSSFP were comparable and had a T2-like contrast behavior, although more accentuated in ATR-SSFP. The ATR-SSFP scored significantly higher than FS-bSSFP for 9

  16. Maximum usable thickness revisited: Imaging dislocations in Si by modern high-voltage scanning transmission electron microscopy

    Science.gov (United States)

    Sato, Kazuhisa; Yamashita, Yuki; Yasuda, Hidehiro; Mori, Hirotaro

    2017-10-01

    We have quantitatively evaluated the usable thickness of specimens in scanning transmission electron microscopy (STEM) at 1 MV using a wedge-shaped Si(110) single crystal including artificially introduced high-density dislocations. The width of dislocation images was employed as a criterion for the quantitative evaluation of usable thickness. Superior usable thickness in STEM than in TEM was found; the obtained results were 14.7 µm for STEM and 5.8 µm for TEM. In particular, in STEM, dislocations can be observed as thin lines with 10-15 nm width in the thickness range up to 10 µm. The latest high-voltage STEM is useful for imaging crystal defects in thick semiconductors.

  17. Synthesis, electrochemistry, STM investigation of oligothiophene self-assemblies with superior structural order and electronic properties

    Science.gov (United States)

    Kuo, Cheng-Yu; Liu, Yinghao; Yarotski, Dmitry; Li, Hao; Xu, Ping; Yen, Hung-Ju; Tretiak, Sergei; Wang, Hsing-Lin

    2016-12-01

    Three oligothiophene (terthiophene, tetrathiophene and pentathiophene) derivatives are synthesized and their monolayer self-assemblies on gold (Au) are prepared via Au-S covalent bond. Our UV-Vis experimental characterization of solution reveals the dependence of the optical properties on the conjugation length of the oligothiophenes, which compares well with Time-Dependent Density Functional Theory (TDDFT) simulations of spectra of individual chromophores. Photoluminescent spectra of thin films show pronounced red shifts compared to that of solutions, suggesting strong inter-oligomer interactions. The comparative studies of cyclic voltammograms of tetrathiophene from solution, cast film and self-assembled monolayer (SAM) indicate presence of one, two, and three oxidized species in these samples, respectively, suggesting a very strong electronic coupling between tetrathiophene molecules in the SAM. Scanning tunneling microscopy (STM) imaging of SAMs of the tetrathiophene on an atomically flat Au surface exhibits formation of monolayer assemblies with molecular order, and the molecular packing appears to show an overlay of oligothiophene molecules on top of another one. In contrast, the trimer and pentamer images show only aggregated species lacking long-range order on the molecular level. Such trends in going from disordered-ordered-disordered monolayer assemblies are mainly due to a delicate balance between inter-chromophore π-π couplings, hydrophobic interaction and the propensity to form Au-S covalent bond. Such hypothesis has been validated by our computational results suggesting different interaction patterns of oligothiophenes with odd numbered and even numbered thiophene repeat units placed in a dimer configuration. Observed correlations between oligomer geometry and structural order of monolayer assembly elucidate important structure-property relationships and have implications for these molecular structures in organic optoelectronic devices and energy

  18. Toward a robust workflow for deep crustal imaging by FWI of OBS data: The eastern Nankai Trough revisited

    Science.gov (United States)

    Górszczyk, Andrzej; Operto, Stéphane; Malinowski, Michał

    2017-06-01

    Crustal-scale imaging by the full-waveform inversion (FWI) of long-offset seismic data is inherently difficult because the large number of wavelengths propagating through the crust makes the inversion prone to cycle skipping. Therefore, efficient crustal-scale FWI requires an accurate starting model and a stable workflow minimizing the nonlinearity of the inversion. Here we attempt to reprocess a challenging 2-D ocean-bottom seismometer (OBS) data set from the eastern Nankai Trough. The starting model is built by first-arrival traveltime tomography (FAT), which is FWI assisted for tracking cycle skipping. We iteratively refine the picked traveltimes and then reiterate the FAT until the traveltime residuals remain below the cycle-skipping limit. Subsequently, we apply Laplace-Fourier FWI, in which progressive relaxation of time damping is nested within frequency continuation to hierarchically inject more data into the inversion. These two multiscale levels are complemented by a layer-stripping approach implemented through offset continuation. The reliability of the FWI velocity model is assessed by means of source wavelet estimation, synthetic seismogram modeling, ray tracing modeling, dynamic warping, and checkerboard tests. Although the viscoacoustic approximation is used for wave modeling, the synthetic seismograms reproduce most of the complexity of the data with a high traveltime accuracy. The revised FWI scheme produces a high-resolution velocity model of the entire crust that can be jointly interpreted with migrated images derived from multichannel seismic data. This study opens a new perspective on the design of OBS crustal-scale experiments amenable to FWI; however, a further assessment of the optimal OBS spacing is required for reliable FWI.

  19. A Versatile Molecular Beam Epitaxy System for Low-Temperature STM: Instrument Design and Initial Results

    Science.gov (United States)

    Bowman, Adam; Ding, Hao; Jeon, Sangjun; Yazdani, Ali

    Efficient combination of molecular beam epitaxy (MBE) with scanning tunneling microscopy (STM) is essential for engineering and studying new materials with topological and superconducting properties. Particularly valuable are the capabilities to grow clean material interfaces, single monolayer films, and 2D systems with proximitized superconductivity. A new MBE system designed for STM was constructed to allow reliable ultra-high vacuum sample transfer, growth between 77 K and 1500 K, direct current sample flashing, and RHEED surface monitoring. Six Knudsen cells and electron beam evaporators allow growth of a variety of superconducting, topological, and metallic films. UHV transfer from the MBE via a vacuum suitcase can be accomplished within an hour to preserve clean surfaces. Initial low-temperature STM results on bismuth and monolayer iron selenide (FeSe) films will be presented. This work is supported by the Moore Foundation, ONR, and NSF.

  20. Design and implementation of FIR filter based on STM32F103x

    Directory of Open Access Journals (Sweden)

    ZHENG Zhendong

    2013-08-01

    Full Text Available STM32F1 series processors are based on ST's new generation of ARM cortex-M3 processor core to meet the industrial control,medical,consumer and other areas of application requirements. At the same time,ST companies also launched a set of DSP function library for the STM32F10x series,enabling common digital signal processing. In this paper,a set of FIRfilter design and implementation is proposed for the STM32F10x series. Experiments show that the integer filter coefficients can replace the float coefficients in FIRfilter design. When the sampling rate is 256 samples per second,the FIRfilter is of the order of 128 and takes only 1.5ms to finish filtering 256 samples,fully meeting the design requirements for industrial control systems.

  1. Revisiting a historic human brain with magnetic resonance imaging – the first description of a divided central sulcus

    Directory of Open Access Journals (Sweden)

    Renate eSchweizer

    2014-05-01

    Full Text Available In 1860 and 1862, the German physiologist Wagner published two studies, in which he compared the cortical surfaces of brain specimens. This provided the first account of a rare anatomical variation – bridges across the central sulci in both hemispheres connecting the forward and backward facing central convolutions in one of the brains. The serendipitous rediscovery of the preserved historic brain specimen in the collections at Göttingen University, being mistaken as the brain of the mathematician C.F. Gauss, allowed us to further investigate the morphology of the bridges Wagner had described with magnetic resonance imaging (MRI. On the historic lithograph, current photographs and MRI surface reconstructions of the brain, a connection across the central sulcus can only be seen in the left hemisphere. In the right hemisphere, contrary to the description of Wagner, a connecting structure is only present across the postcentral sulcus. MRI reveals that the left-hemispheric bridge extends into the depth of the sulcus, forming a transverse connection between the two opposing gyri. This rare anatomical variation, generally not associated with neurological symptoms, would nowadays be categorized as a divided central sulcus. The left-hemispheric connection seen across the postcentral sulcus, represents the very common case of a segmented postcentral sulcus. MRI further disclosed a connection across the right-hemispheric central sulcus, which terminates just below the surface of the brain and is therefore not depicted on the historical lithography. This explains the apparent inconsistency between the bilateral description of bridges across the central sulci and the unilateral appearance on the brain surface. The results are discussed based on the detailed knowledge of anatomists of the late 19th century, who already recognized the divided central sulcus as an extreme variation of a deep convolution within the central sulcus.

  2. Revisiting a historic human brain with magnetic resonance imaging - the first description of a divided central sulcus.

    Science.gov (United States)

    Schweizer, Renate; Helms, Gunther; Frahm, Jens

    2014-01-01

    In 1860 and 1862, the German physiologist Wagner published two studies, in which he compared the cortical surfaces of brain specimens. This provided the first account of a rare anatomical variation - bridges across the central sulci in both hemispheres connecting the forward and backward facing central convolutions in one of the brains. The serendipitous rediscovery of the preserved historic brain specimen in the collections at Göttingen University, being mistaken as the brain of the mathematician C.F. Gauss, allowed us to further investigate the morphology of the bridges Wagner had described with magnetic resonance imaging (MRI). On the historic lithograph, current photographs and MRI surface reconstructions of the brain, a connection across the central sulcus can only be seen in the left hemisphere. In the right hemisphere, contrary to the description of Wagner, a connecting structure is only present across the post-central sulcus. MRI reveals that the left-hemispheric bridge extends into the depth of the sulcus, forming a transverse connection between the two opposing gyri. This rare anatomical variation, generally not associated with neurological symptoms, would nowadays be categorized as a divided central sulcus. The left-hemispheric connection seen across the post-central sulcus, represents the very common case of a segmented post-central sulcus. MRI further disclosed a connection across the right-hemispheric central sulcus, which terminates just below the surface of the brain and is therefore not depicted on the historical lithography. This explains the apparent inconsistency between the bilateral description of bridges across the central sulci and the unilateral appearance on the brain surface. The results are discussed based on the detailed knowledge of anatomists of the late 19th century, who already recognized the divided central sulcus as an extreme variation of a deep convolution within the central sulcus.

  3. Molecular assembly and electropolymerization of 3,4-ethylenedioxythiophene on Au(111) single crystal electrode as probed by in situ electrochemical STM in 0.10 M HClO4.

    Science.gov (United States)

    Lapitan, Lorico D S; Tongol, Bernard John V; Yau, Shueh-Lin

    2010-07-06

    We have used electrochemical scanning tunneling microscopy (EC-STM) to obtain molecular insights on the adlayer structures and electrochemical polymerization of 3,4-ethylenedioxythiophene (EDOT) on a bare Au(111) single crystal electrode in 0.1 M HClO(4) solution. Cyclic voltammetric (CV) studies showed an increase in anodic current at 0.90 V with the oxidation of EDOT monomer occurring at E = 1.10 V (vs reversible hydrogen electrode). In situ STM revealed, for the first time, that EDOT molecules can spontaneously form organized adlayers on a bare Au(111) surface with 18 muM concentration of EDOT in aqueous solution. Molecularly resolved STM images of the EDOT adlayer showed two domains consisting of disordered and ordered structures with the formation of vacancy islands or "etch pits". Several EDOT structures were observed at +0.60 V, namely, (4 x 7), (5 x square root(37)), and (square root(7) x 3) with calculated coverages of 0.107, 0.114, and 0.111 ML, respectively. Electropolymerization was also carried out using in situ STM in 0.10 M HClO(4) under potential control.

  4. Techniques Use by Science, Technology and Mathematics (STM) Teachers for Controlling Undesirable Classroom Behaviours in Anambra State Secondary Schools

    Science.gov (United States)

    Chinelo, Okigbo Ebele; Nwanneka, Okoli Josephine

    2016-01-01

    This study investigated the techniques used by secondary school Science Technology and Mathematics (STM) teachers in controlling undesirable behaviours in their classrooms. It adopted descriptive survey design in which 178 Anambra State teachers teaching STM subjects in senior secondary were involved in the research. Two sections of questionnaire…

  5. STM and STS investigation of ultrathin tin phthalocyanine layers adsorbed on HOPG(0001) and Au(111)

    DEFF Research Database (Denmark)

    Walzer, Karsten; Hietschold, M.

    2001-01-01

    The initial adsorption of tin phthalocyanine (SnPc) on graphite and gold surfaces was studied by low-temperature UHV-STM. At submonolayer coverages on highly oriented pyrolytic graphite (HOPG), SnPc forms substrate-defined molecular chains, while SnPc monolayers reveal dense packed structures...

  6. Adaptation of Acoustic Model Experiments of STM via Smartphones and Tablets

    Science.gov (United States)

    Thees, Michael; Hochberg, Katrin; Kuhn, Jochen; Aeschlimann, Martin

    2017-01-01

    The importance of Scanning Tunneling Microscopy (STM) in today's research and industry leads to the question of how to include such a key technology in physics education. Manfred Euler has developed an acoustic model experiment to illustrate the fundamental measuring principles based on an analogy between quantum mechanics and acoustics. Based on…

  7. STM-induced light emission from vacuum-evaporated gold film

    Indian Academy of Sciences (India)

    Administrator

    1271. STM-induced light emission from vacuum-evaporated gold film. J U AHAMED1,*, S KATANO2 and Y UEHARA2. 1Department of Applied Physics, Electronics and Communication Engineering, University of Chittagong,. Chittagong 4331, Bangladesh. 2Research Institute of Electrical Communication, Tohoku University, ...

  8. Repetition and verbal STM in transcortical sensory aphasia: a case study.

    Science.gov (United States)

    Martin, N; Saffran, E M

    1990-08-01

    The repetition performance of a patient (S.T.) with transcortical sensory aphasia is examined in four experiments with particular emphasis on the STM capacities underlying her performance. S.T.'s repetition of word strings exceeding her span (two words) is characterized by good recall of the final items and a strong tendency to lose the initial items in the input string. This pattern contrasts with the serial position effects observed in a phonologically based STM impairment, and it is suggested that a lexical-semantic impairment, also evident in S.T.'s naming and lexical comprehension, contributes to her inability to retain the primacy portions of the input string. Lexical effects obtained in her reproduction of words and nonwords, as well as word strings (Experiments 1 and 2), indicate that under conditions of impaired semantics S.T. is relying on lexical phonological information to repeat. Priming by repeated exposure (Experiment 3) failed to improve her repetition performance, indicating that access to lexical information is brief and dependent on recent phonological input. In Experiment 4, the role of syntactic structure in S.T.'s sentence repetition was examined, and it was shown that syntactic structure affects the recall of order information, but not the number of items recalled. The repetition and verbal STM abilities of this patient, in light of her total language profile, are then evaluated in the context of a language-based view of verbal STM.

  9. Transistor effects and in situ STM of redox molecules at room temperature

    DEFF Research Database (Denmark)

    Albrecht, Tim; Guckian, A; Vos, JG

    2005-01-01

    Inorganic transition metal complexes were identified as potential candidates for transistor-like behavior in an electrochemical scanning tunnelling microscope (STM) configuration at room temperature. The theoretical background has been established based on condensed matter charge transfer theory...... resolution reveal detailed information on their surface structure and scanning tunnelling spectroscopy experiments have shown clear evidence of transistor-like behavior...

  10. Transistor Effects and in situ STM of Redox Molecules at Room Temperature

    DEFF Research Database (Denmark)

    Albrecht, T.; Guckian, A.; Ulstrup, Jens

    2004-01-01

    Inorganic transition metal complexes were identified as potential candidates for transistor-like behaviour in an electrochemical STM configuration at room temperature. The theoretical background has been established based on condensed matter charge transfer theory. It predicts a distinct increase...... into the surface structure. STS experiments are on the way to probe putative transistor-like behaviour....

  11. A method employing STM for the estimation of relative changes in ...

    Indian Academy of Sciences (India)

    – spectroscopy measurements using a scanning tunnelling microscope (STM) were carried out to determine the change in the work function of a W tip following one monolayer (1 ML) deposition of Ni and subsequent annealing at 700 K. The variation in the actual gap voltage obtained from the – data of the clean tip ...

  12. STM-electroluminescence from clustered C3N4 nanodomains synthesized via green chemistry process.

    Science.gov (United States)

    Andrade, E P; Costa, B B A; Chaves, C R; de Paula, A M; Cury, L A; Malachias, A; Safar, G A M

    2018-01-01

    A Scanning Tunneling Microscopy/Spectroscopy (STM/STS) and synchrotron X-ray diffraction study on clustered C3N4 nanoparticles (nanoflakes) is conducted on green-chemistry synthesized samples obtained from chitosan through high power sonication. Morphological aspects and the electronic characteristics are investigated. The observed bandgap of the nanoflakes reveals the presence of different phases in the material. Combining STM morphology, STS spectra and X-ray diffraction (XRD) results one finds that the most abundant phase is graphitic C3N4. A high density of defects is inferred from the XRD measurements. Additionally, STM-electroluminescence (STMEL) is detected in C3N4 nanoflakes deposited on a gold substrate. The tunneling current creates photons that are three times more energetic than the tunneling electrons of the STM sample. We ponder about the two most probable models to explain the observed photon emission energy: either a nonlinear optical phenomenon or a localized state emission. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Investigation of broken symmetry of Sb/Cu(111) surface alloys by VT-STM

    CSIR Research Space (South Africa)

    Ndlovu, GF

    2011-07-01

    Full Text Available This work present an in situ Variable Temperature Scanning Tunneling Microscopy (VT-STM) study of the Sb/Cu(111) system studied at various temperatures. The experimental data support a structural model in which Sb atoms displace up to 1...

  14. The Impact of Pointing on the Short-Term Memory (STM) of Heterophonic Homographs

    Science.gov (United States)

    Vaknin-Nusbaum, Vered; Miller, Paul

    2014-01-01

    This study entailed two short-term memory (STM) experiments investigating the importance of vowel diacritics for the temporary retention of three distinct Hebrew word list types: heterophonic homographs, non-homographs and homophonic homographs. Eighty university students participated in each experiment, with half of them tested with word lists…

  15. Recoding between Two Types of STM Representation Revealed by the Dynamics of Memory Search

    Science.gov (United States)

    Leszczynski, Marcin; Myers, Nicholas E.; Akyurek, Elkan G.; Schubo, Anna

    2012-01-01

    Visual STM (VSTM) is thought to be related to visual attention in several ways. Attention controls access to VSTM during memory encoding and plays a role in the maintenance of stored information by strengthening memorized content. We investigated the involvement of visual attention in recall from VSTM. In two experiments, we measured…

  16. Recoding between two types of STM representation revealed by the dynamics of memory search

    NARCIS (Netherlands)

    Leszczyński, Marcin; Myers, Nicolas E.; Akyürek, Elkan G.; Schubö, Anna

    Visual STM (VSTM) is thought to be related to visual attention in several ways. Attention controls access to VSTM during memory encoding and plays a role in the maintenance of stored information by strengthening memorized content. We investigated the involvement of visual attention in recall from

  17. High-throughput identification of conditionally essential genes in bacteria: from STM to TSM.

    Science.gov (United States)

    Bossé, J T; Zhou, L; Kroll, J S; Langford, P R

    2006-09-01

    Signature-tagged mutagenesis (STM) provided the first widely applicable high-throughput method for detecting conditionally essential genes in bacteria by using negative selection to screen large pools of transposon (Tn) mutants. STM requires no prior knowledge of the bacterium's genome sequence, and has been used to study a large number of Gram-positive and Gram-negative species, greatly expanding the repertoires of known virulence factors for these organisms. Originally, hybridization of radiolabelled probes to colony or dot blots was used to detect differences in populations of tagged mutants before and after growth under a selective condition. Modifications of the tag detection method involving polymerase chain reaction (PCR) amplification and visualisation by gel electrophoresis have been developed and can be automated through the use of robotics. Genetic footprinting is another negative selection technique that uses PCR amplification to detect loss of mutants from a pool. Unlike PCR-STM, this technique allows direct amplification of Tn-flanking sequences. However, it requires the bacterium's whole genome sequence in order to design specific primers for every gene of interest. More recently, a number of techniques have been described that combine the negative-selection principle of STM and genetic footprinting with the genome-wide screening power of DNA microarrays. These techniques, although also requiring whole genome sequences, use either a form of linker-mediated or semi-random PCR to amplify and label Tn-flanking regions for hybridization to microarrays. The superior sensitivity microarray detection allows greater numbers of mutants to be screened per pool, as well as determination of the coverage/distribution of insertions in the library prior to screening, two significant advantages over STM.

  18. STM, QCM, and the windshield wiper effect: a joint theoretical-experimental study of adsorbate mobility and lubrication at high sliding rates.

    Science.gov (United States)

    Abdelmaksoud, M; Lee, S M; Padgett, C W; Irving, D L; Brenner, D W; Krim, J

    2006-11-07

    We have observed that when mobile adsorbed films of benzene, tricresyl phosphate, and tertiary-butyl phenyl phosphate are present on the surface electrode of a quartz crystal microbalance (QCM), oscillation of the QCM produces clearer scanning tunneling microscope (STM) images of the electrode surface. This is in contrast to an immobile overlayer of iodobenzene, where oscillation of the QCM does not affect image quality. This observation is attributed to a "windshield wiper effect", where at MHz frequencies the tip motion maintains a region of the surface where the absorbate concentration is reduced, which leads to a clearer image. A straightforward model is presented that supports this conclusion and that provides guidelines for effective lubrication of contacts operating at MHz frequencies.

  19. Direct Fabrication of Carbon Nanotubes STM Tips by Liquid Catalyst-Assisted Microwave Plasma-Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Fa-Kuei Tung

    2009-01-01

    Full Text Available Direct and facile method to make carbon nanotube (CNT tips for scanning tunneling microscopy (STM is presented. Cobalt (Co particles, as catalysts, are electrochemically deposited on the apex of tungsten (W STM tip for CNT growth. It is found that the quantity of Co particles is well controlled by applied DC voltage, concentration of catalyst solution, and deposition time. Using optimum growth condition, CNTs are successfully synthesized on the tip apex by catalyst-assisted microwave-enhanced chemical vapor deposition (CA-MPECVD. A HOPG surface is clearly observed at an atomic scale using the present CNT-STM tip.

  20. Revisiting the Okun relationship

    NARCIS (Netherlands)

    Dixon, R. (Robert); Lim, G.C.; J.C. van Ours (Jan)

    2017-01-01

    textabstractOur article revisits the Okun relationship between observed unemployment rates and output gaps. We include in the relationship the effect of labour market institutions as well as age and gender effects. Our empirical analysis is based on 20 OECD countries over the period 1985–2013. We

  1. Revisiting Okun's Relationship

    NARCIS (Netherlands)

    Dixon, R.; Lim, G.C.; van Ours, Jan

    2016-01-01

    Our paper revisits Okun's relationship between observed unemployment rates and output gaps. We include in the relationship the effect of labour market institutions as well as age and gender effects. Our empirical analysis is based on 20 OECD countries over the period 1985-2013. We find that the

  2. Random eigenvalue problems revisited

    Indian Academy of Sciences (India)

    Several studies have been conducted on this topic since the mid-sixties. The. A list of .... Random eigenvalue problems revisited. 297 and various elements of Hij ,i ≤ j are statistically independent and Gaussian. The pdf of H can be expressed as, ...... Generality of this result however remains to be verified in future studies.

  3. Revisiting Professional Teacher Standards

    Science.gov (United States)

    Watson, Amanda

    2016-01-01

    The Australian Society for Music Education's (ASME) involvement in the development of professional standards for music educators was a significant and active research time in the history of the Society. As ASME celebrates its golden jubilee, it is appropriate to revisit that history and consider the future prospects of subject-specific standards.…

  4. Revisiting city connectivity

    NARCIS (Netherlands)

    Mans, U.

    2014-01-01

    This article introduces a new perspective on city connectivity in order to analyze non-hub cities and their position in the world economy. The author revisits the different approaches discussed in the Global Commodity Chains (GCC), Global Production Networks (GPN) and World City Network (WCN)

  5. The Faraday effect revisited

    DEFF Research Database (Denmark)

    Cornean, Horia; Nenciu, Gheorghe

    2009-01-01

    This paper is the second in a series revisiting the (effect of) Faraday rotation. We formulate and prove the thermodynamic limit for the transverse electric conductivity of Bloch electrons, as well as for the Verdet constant. The main mathematical tool is a regularized magnetic and geometric...

  6. Josephson STM at mK temperatures: Coupling to the electronic environment

    Science.gov (United States)

    Dreyer, Michael; Dana, Rami; Liao, Wan-Ting; Lobb, Cris; Wellstood, Fred; Anderson, Bob

    Ultra-small Josephson junctions can couple to modes in the electronic environment. This leads to sub-gap peaks in the I(V) curve in addition to the phase diffuse supercurrent. The I(V) curve can - in principle - be explained by P(E) theory which describes the probability of tunneling at energy E. A recent study showed that antenna modes of the STM tips could be responsible for the observed sideband structures. In our case the explanation appears to be less simple. We employ a dual tip STM at a temperature of 30 mK. The I(V) spectra of the two tips show distinct patterns with only one shared mode. While the supercurrent branch for the ''inner'' tip is visible, it is obscured by a resonance for the ``outer'' tip. Possible causes and applications to other systems will be discussed. Support from NSF (DMR- 0605763) and Laboratory for Physical Sciences.

  7. Automated extraction of single H atoms with STM: tip state dependency

    Science.gov (United States)

    Møller, Morten; Jarvis, Samuel P.; Guérinet, Laurent; Sharp, Peter; Woolley, Richard; Rahe, Philipp; Moriarty, Philip

    2017-02-01

    The atomistic structure of the tip apex plays a crucial role in performing reliable atomic-scale surface and adsorbate manipulation using scanning probe techniques. We have developed an automated extraction routine for controlled removal of single hydrogen atoms from the H:Si(100) surface. The set of atomic extraction protocols detect a variety of desorption events during scanning tunneling microscope (STM)-induced modification of the hydrogen-passivated surface. The influence of the tip state on the probability for hydrogen removal was examined by comparing the desorption efficiency for various classifications of STM topographs (rows, dimers, atoms, etc). We find that dimer-row-resolving tip apices extract hydrogen atoms most readily and reliably (and with least spurious desorption), while tip states which provide atomic resolution counter-intuitively have a lower probability for single H atom removal.

  8. Ethylene dissociation on flat and stepped Ni(111): A combined STM and DFT study

    DEFF Research Database (Denmark)

    Vang, R.T.; Honkala, Johanna Karoliina; Dahl, S.

    2006-01-01

    evaporation leads to a step flow growth of Ag islands, and a subsequent annealing at 800 K causes the Ag atoms to completely wet the step edges of Ni(111). The blocking of the step edges is shown to prevent all decomposition of ethylene at room temperature, whereas the terrace site decomposition at 500 K......The dissociative adsorption of ethylene (C(2)H(4)) on Ni(111) was studied by scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. The STM studies reveal that ethylene decomposes exclusively at the step edges at room temperature. However, the step edge sites...... are poisoned by the reaction products and thus only a small brim of decomposed ethylene is formed. At 500 K decomposition on the (111) facets leads to a continuous growth of carbidic islands, which nucleate along the step edges. DFT calculations were performed for several intermediate steps...

  9. Single-molecule vibrational spectroscopy of water molecules using an LT-STM

    Science.gov (United States)

    Matsumoto, Chikako; Kim, Yousoo; Motobayashi, Kenta; Kawai, Maki

    2006-03-01

    Single-molecule vibrational spectroscopy has attracted considerable attention as a powerful tool for nanoscale chemistry. The adsorption of water molecules on metal surfaces plays an important role in understanding many phenomena in nature, such as heterogeneous catalysis and corrosion, etc. The structure of water at low coverage has been investigated on a variety of transition-metal surfaces with various techniques. But the microscopic understanding of the adsorption feature of single water molecules is still unclear. We report molecular scale study of adsorption behaviors of water molecules on Pt (111) surface at 4.7 K by use of single-molecule vibrational spectroscopy with the scanning tunneling microscopy (STM). The Pt (111) surface was dosed with a small amount of water molecules (cherry blossom', which can be explained by one of the water molecules rotating around the other. Inelastic electron tunneling spectroscopy using the STM was utilized to determine vibrational modes of individual water dimers.

  10. Tip-Dependent Scanning Tunneling Microscopy Imaging of Ultrathin FeO Films on Pt(111)

    DEFF Research Database (Denmark)

    Merte, Lindsay Richard; Grabow, Lars C.; Peng, Guowen

    2011-01-01

    -vacancy dislocation loops in the FeO moiré structure. The experimental STM results are compared with the results of electronic structure calculations within the DFT+U scheme for a realistic (sqrt(91)xsqrt(91)R5.2 moiré unit cell supported on Pt(111) as well as with the results from previous studies. We find that one...... type of STM imaging mode, showing both Fe and O atoms, agrees well with simulated STM images, indicating that the simple Tersoff-Hamann theory is partially valid for this imaging mode. In addition, we identify other distinct, element-specific imaging modes which reveal a strong dependence...

  11. In-situ STM study of sulfide adsorption on Au(100) in alkaline solution

    DEFF Research Database (Denmark)

    Schlaup, Christian Georg; Wandelt, Klaus

    2015-01-01

    The adsorption of sulfide on a Au(100) electrode from a 0.01 M NaOH + 0.5 mM Na2S electrolyte was studied by in situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV). Starting with a sulfur free electrode surface at low potentials the subsequent formation of a p(2 × 2)-S, a c(2 × 6...

  12. Fabrication of tuning-fork based AFM and STM tungsten probe

    KAUST Repository

    Al-Falih, Hisham

    2011-12-01

    We compare the sharpness of tungsten probe tips produced by the single-step and two-step dynamic electrochemical etching processes. A small radius of curvature (RoC) of 25 nm or less was routinely obtained when the two-step electrochemical etching (TEE) process was adopted, while the smallest achievable RoC was ∼10 nm, rendering it suitable for atomic force microscopy (AFM) or scanning tunneling microscopy (STM) applications. © 2011 IEEE.

  13. Morphological analysis of stainless steel scale like surface morphology using STM and AFM

    Energy Technology Data Exchange (ETDEWEB)

    Vignal, V.; Olive, J.M.; Desjardins, D. [Univ. Bordeaux 1, Talence (France). Lab. de Mecanique-Physique; Roux, J.C.; Genton, V. [Univ. de Bordeaux-1, Pessac (France). Centre de Recherche Paul Pascal

    1997-12-19

    A combined atomic force microscopy (AFM) and scanning tunneling microscopy (STM) investigation of stainless steel like surface morphology formed either in electropolishing bath or in HNO{sub 3} medium is reported. A new numerical technique using the Nanoscope III software is proposed. The dimension, slope and orientation of scales can be easily determined. Moreover, grain boundaries structure and probable oxides present in the upper part of the film can be deduced.

  14. Design and Characterization of a millikelvin dual-tip Josephson STM

    Science.gov (United States)

    Roychowdhury, A.; Dreyer, M.; Anderson, J. R.; Lobb, C. J.; Wellstood, F. C.

    2014-03-01

    We describe the design and characterization of a dual-tip Josephson STM that operates at millikelvin temperatures. We report an effective noise temperature for the STM on the order of 200 mK. In addition to the expected phase diffusive super current in the ultra-small Nb-Nb junction formed by one tip and the sample, our high resolution spectroscopy at mK temperatures reveals resonant coupling between the STM junction and the electromagnetic environment it is embedded in, as predicted by P(E) theory. We have for the first time, observed Shapiro-like steps in this limit by measuring the response of the P(E) supercurrent to microwave radiation as a function of amplitude. Fits to theory indicate that the coupling of an ultra-small Josephson junction to its environment/circuit may be used to a) directly measure dissipation channels associated with circuit resonances and b) calibrate the frequency dependent microwave attenuation in cryogenic circuits as seen by the junction.

  15. Measuring exchange interactions between atomic spins using electron spin resonance STM

    Science.gov (United States)

    Yang, Kai; Paul, William; Natterer, Fabian; Choi, Taeyoung; Heinrich, Andreas; Lutz, Christopher

    Exchange interactions between neighboring atoms give rise to magnetic order in magnetic materials. As the size of the electronic device is miniaturized toward the limit of single atoms, magnetic nanostructures such as coupled atomic dimers and clusters are explored more as prototypes for possible data storage, spintronics as well as quantum computing applications. Characterizing inter-atom exchange interactions calls for increasing spatial resolution and higher energy sensitivity to better understand this fundamental interaction. Here, using spin-polarized scanning tunneling microscopy (STM), we studied a magnetically coupled atomic dimer consisting of two 3d transition metal atoms, with one adsorbed on an insulating layer (MgO) and the other attached to the STM tip. We demonstrate the ability to measure the short-range exchange interaction between the two atomic spins with orders-of-magnitude variation ranging from milli-eV all the way to micro-eV. This is realized by the successful combination of inelastic electron tunneling spectroscopy (IETS) and electron spin resonance (ESR) techniques in STM implemented at different energy scales. We unambiguously confirm the exponential decay behavior of the direct exchange interaction.

  16. Structure Determination of Au on Pt(111 Surface: LEED, STM and DFT Study

    Directory of Open Access Journals (Sweden)

    Katarzyna Krupski

    2015-05-01

    Full Text Available Low-energy electron diffraction (LEED, scanning tunneling microscopy (STM and density functional theory (DFT calculations have been used to investigate the atomic and electronic structure of gold deposited (between 0.8 and 1.0 monolayer on the Pt(111 face in ultrahigh vacuum at room temperature. The analysis of LEED and STM measurements indicates two-dimensional growth of the first Au monolayer. Change of the measured surface lattice constant equal to 2.80 Å after Au adsorption was not observed. Based on DFT, the distance between the nearest atoms in the case of bare Pt(111 and Au/Pt(111 surface is equal to 2.83 Å, which gives 1% difference in comparison with STM values. The first and second interlayer spacing of the clean Pt(111 surface are expanded by +0.87% and contracted by −0.43%, respectively. The adsorption energy of the Au atom on the Pt(111 surface is dependent on the adsorption position, and there is a preference for a hollow fcc site. For the Au/Pt(111 surface, the top interlayer spacing is expanded by +2.16% with respect to the ideal bulk value. Changes in the electronic properties of the Au/Pt(111 system below the Fermi level connected to the interaction of Au atoms with Pt(111 surface are observed.

  17. STM and AFM of bio/organic molecules and structures

    Science.gov (United States)

    Ikai, Atsushi

    Applications of scanning tunneling and atomic force microscopes in bio/organic researches are reviewed with a special emphasis on the types of researches that are expected to contribute to the creation of a new field of "single molecule biochemistry" in the near future. The reviewed articles within the scope as stated above actually include a fairly broad spectrum of researches. It is, therefore, a hope of the author that this review will be useful to those who are considering biological applications of the probe microscopy techniques but are not quite familiar with the types of experiments that have been done in the past. In the section on scanning tunneling microscopy, identification of chemically distinct functional groups by the difference in their tunneling properties will be discussed as a main focus because it is fundamental for biochemists to identify molecules by their shapes and properties. In the section on atomic force microscopy, recent progresses in the imaging techniques of proteins and DNAs are closely reviewed, and rapidly advancing technologies of single molecule measurements and manipulation of nanometer sized structures are given extensive coverage because the author considers that such new applications are extremely promising to open an entirely new field in biological sciences.

  18. Observation of the Gap Distribution on Multi-layered Cuprate Superconductor Ba2Ca4Cu5O10(O1-x, Fx)2 by STM/STS

    Science.gov (United States)

    Sugimoto, Akira; Ekino, Toshikazu; Tanaka, Katsuhiro; Mineta, Kyohei; Tanabe, Kenji; Tokiwa, Kazuyasu

    The nano-scale spatial gap distributions on apical-fluorine multi-layered cuprate superconductors Ba2Ca4Cu5O10(O1-x, Fx) (F0245, Tc = 70 K) are investigated by scanning tunneling microscopy/spectroscopy (STM/STS). The STM image shows randomly-distributed bright spot structures, which are assigned to the non-replaced apical oxygen. The dI/dV tunnel spectra show the coexistence of two kinds of the gap structures. The magnitudes of these gaps at 4.9 K are about ΔS ∼25 meV and ΔL ∼78 meV, respectively. The ΔL map shows the inhomogeneous distribution with the characteristic length of ∼1 nm. The smaller ΔL gap regions tend to locate at the bright-spot positions, indicating that the apical oxygen causes reduction of ΔL. These results are consistent with the well known relation between the carrier doping level and macroscopically observed gap size.

  19. Revisiting Lambert's Problem

    OpenAIRE

    Izzo, Dario

    2014-01-01

    The orbital boundary value problem, also known as Lambert Problem, is revisited. Building upon Lancaster and Blanchard approach, new relations are revealed and a new variable representing all problem classes, under L-similarity, is used to express the time of flight equation. In the new variable, the time of flight curves have two oblique asymptotes and they mostly appear to be conveniently approximated by piecewise continuous lines. We use and invert such a simple approximation to provide an...

  20. Deterministic Graphical Games Revisited

    DEFF Research Database (Denmark)

    Andersson, Daniel; Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro

    2008-01-01

    We revisit the deterministic graphical games of Washburn. A deterministic graphical game can be described as a simple stochastic game (a notion due to Anne Condon), except that we allow arbitrary real payoffs but disallow moves of chance. We study the complexity of solving deterministic graphical...... games and obtain an almost-linear time comparison-based algorithm for computing an equilibrium of such a game. The existence of a linear time comparison-based algorithm remains an open problem....

  1. Demographic Dividends Revisited

    OpenAIRE

    Jeffrey G. Williamson

    2013-01-01

    This paper revisits demographic dividend issues after almost 2 decades of debate. In 1998, David Bloom and I used a convergence model to estimate the impact of demographic-transition-driven age structure effects and calculated what the literature has come to call the “demographic dividend.” These early estimates seem to be similar to those coming from more recent overlapping generation models, when properly estimated. Research has shown that the demographic dividend is not simply a labor part...

  2. Clinical ethics revisited

    Directory of Open Access Journals (Sweden)

    Pellegrino Edmund D

    2001-04-01

    Full Text Available Abstract A decade ago, we reviewed the field of clinical ethics; assessed its progress in research, education, and ethics committees and consultation; and made predictions about the future of the field. In this article, we revisit clinical ethics to examine our earlier observations, highlight key developments, and discuss remaining challenges for clinical ethics, including the need to develop a global perspective on clinical ethics problems.

  3. Adaptation of acoustic model experiments of STM via smartphones and tablets

    Science.gov (United States)

    Thees, Michael; Hochberg, Katrin; Kuhn, Jochen; Aeschlimann, Martin

    2017-10-01

    The importance of Scanning Tunneling Microscopy (STM) in today's research and industry leads to the question of how to include such a key technology in physics education. Manfred Euler has developed an acoustic model experiment to illustrate the fundamental measuring principles based on an analogy between quantum mechanics and acoustics. Based on earlier work we applied mobile devices such as smartphones and tablets instead of using a computer to record and display the experimental data and thus converted Euler's experimental setup into a low-cost experiment that is easy to build and handle by students themselves.

  4. The Nature of Surface States on Vicinal Cu (775): An STM and Photoemission Study

    OpenAIRE

    Zaki, Nader; Knox, Kevin; Osgood, Richard M.; Johnson, Peter D.; Fujii, Jun; Vobornik, Ivana; Panaccione, Giancarlo

    2014-01-01

    We report ARPES and a set of in situ STM measurements on a narrow-terrace-width vicinal Cu(111) crystal surface, Cu(775), whose vicinal cut lies close to the transition between terrace and step modulation. These measurements show sharp zone-folding (or Umklapp) features with a periodicity in k||, indicating that the predominant reference plane is that of Cu(775), i.e. that the surface is predominately step-modulated. Our measurements also show variation in Umklapp intensity with photon energy...

  5. Bonding of anthracene derivatives to a Cu (111) surface: a combined STM and DFT study

    Science.gov (United States)

    Wyrick, Jonathan; Zhu, Yeming; Salib, Daniel; Holzke, Connor; Cheng, Zhihai; Bartels, Ludwig

    2013-03-01

    We compare and contrast three anthracene derivatives whose 9,10 hydrogens are replaced by the elements O, S, and Se respectively that act as ``feet'' binding the molecules to a Cu (111) substrate. DFT calculations are compared with and shed light on STM data for the three molecules. We analyze the three species in terms of their geometric and electronic structure upon adsorption, taking into account the competing effects that the ``feet'' have with the anthracene moiety in their interactions with the underlying Cu surface. At the time of contributed research, Zhihai was at University of California at Riverside

  6. In situ STM observation of the CO adlayer on a Pt(110) electrode in 0.1 M HClO4 solution.

    Science.gov (United States)

    Wakisaka, Mitsuru; Asizawa, Shuichi; Yoneyama, Toshiki; Uchida, Hiroyuki; Watanabe, Masahiro

    2010-06-15

    We have obtained the first in situ STM molecular image of a CO adlayer on a Pt(110)-(1 x 1) electrode surface in 0.1 M HClO(4) solution. The observed CO adlayer formed an ordered (2 x 1)-2CO structure at saturated coverage. The CO molecules were found to adsorb on top of each Pt surface atom; however, they were tilted with a zigzag configuration along the atomic rows because of the dipole-dipole repulsion of neighboring CO molecules. The high activity of the Pt(110) electrode for surface CO oxidation can be attributed to the low packing density of the adsorbed CO molecules as well as their tilted orientation.

  7. Water adsorption on O(2x2)/Ru(0001) from STM experiments andfirst-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera-Sanfelix, P.; Sanchez-Portal, D.; Mugarza, A.; Shimizu,T.K.; Salmeron, M.; Arnau, A.

    2007-10-15

    We present a combined theoretical and experimental study of water adsorption on Ru(0001) pre-covered with 0.25 monolayers (ML) of oxygen forming a (2 x 2) structure. Several structures were analyzed by means of Density Functional Theory calculations for which STM simulations were performed and compared with experimental data. Up to 0.25 monolayers the molecules bind to the exposed Ru atoms of the 2 x 2 unit cell via the lone pair orbitals. The molecular plane is almost parallel to the surface with its H atoms pointing towards the chemisorbed O atoms of the 2 x 2 unit cell forming hydrogen bonds. The existence of these additional hydrogen bonds increases the adsorption energy of the water molecule to approximately 616 meV, which is {approx}220 meV more stable than on the clean Ru(0001) surface with a similar configuration. The binding energy shows only a weak dependence on water coverage, with a shallow minimum for a row structure at 0.125 ML. This is consistent with the STM experiments that show a tendency of the molecules to form linear rows at intermediate coverage. Our calculations also suggest the possible formation of water dimers near 0.25 ML.

  8. Quantum dynamics of STM and laser induced desorption of atoms and molecules from surfaces

    CERN Document Server

    Boendgen, G

    2001-01-01

    The manipulation of atoms and molecules at solid surfaces by electronic excitations with electrons (or holes) emitted from the tip of a scanning tunneling microscope (STM) or with laser radiation is both of applied and fundamental interest, e.g. for micro- and nanostructuring of materials, the clarification of elementary (catalytic) reaction mechanisms and for the question of how to treat the quantum dynamics of a laser or STM driven 'system' (the adsorbate) in contact with a dissipative (energy-withdrawing) 'bath' (the substrate). Desorption induced by electronic transitions (DIET) and its variant DIMET (M = multiple) are among the simplest possible 'reactions' of adsorbate-surface systems; usually involving extremely short-lived electronically excited intermediates. In this thesis, the ultra-short dynamics of directly (localised to the adsorbate-substrate complex) and indirectly (i.e., through the substrate) stimulated DIET and DIMET processes was studied for Si(100)-(2x1):H(D) and Pt(111):NO. Isotope effec...

  9. Static Application-Level Race Detection in STM Haskell using Contracts

    Directory of Open Access Journals (Sweden)

    Romain Demeyer

    2013-12-01

    Full Text Available Writing concurrent programs is a hard task, even when using high-level synchronization primitives such as transactional memories together with a functional language with well-controlled side-effects such as Haskell, because the interferences generated by the processes to each other can occur at different levels and in a very subtle way. The problem occurs when a thread leaves or exposes the shared data in an inconsistent state with respect to the application logic or the real meaning of the data. In this paper, we propose to associate contracts to transactions and we define a program transformation that makes it possible to extend static contract checking in the context of STM Haskell. As a result, we are able to check statically that each transaction of a STM Haskell program handles the shared data in a such way that a given consistency property, expressed in the form of a user-defined boolean function, is preserved. This ensures that bad interference will not occur during the execution of the concurrent program.

  10. Irving Langmuir Prize in Chemical Physics Lecture: The Inner Machinery of Single Molecules: resolving the unresolved with the STM

    Science.gov (United States)

    Ho, Wilson

    2013-03-01

    The scanning tunneling microscope (STM) is a unique instrument that can probe and induce changes in a molecule with atomic scale resolution. Its operation is based on the current that flows between the tip and the substrate with the molecule sandwiched in between. Therefore, the STM can be used to understand the coupling of electrons to the different states and excitations in the molecule and to investigate the influence on them by its environment. From the spatial and energy dependences of the coupling to the charge, spin, and nuclear motions in the molecule, verification of and new insights into the quantum mechanical properties of molecules can be obtained, including the discovery of new conduction and energy transfer mechanisms. This understanding of electron-molecule interactions with the STM enables rational ways to control chemistry and the exploration of novel physical technologies based on molecules.

  11. Bottomonium spectrum revisited

    CERN Document Server

    Segovia, Jorge; Entem, David R.; Fernández, Francisco

    2016-01-01

    We revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model which has been applied to a wide range of hadronic observables from the light to the heavy quark sector and thus the model parameters are completely constrained. Beyond the spectrum, we provide a large number of electromagnetic, strong and hadronic decays in order to discuss the quark content of the bottomonium states and give more insights about the better way to determine their properties experimentally.

  12. Leukemia and ionizing radiation revisited

    Energy Technology Data Exchange (ETDEWEB)

    Cuttler, J.M. [Cuttler & Associates Inc., Vaughan, Ontario (Canada); Welsh, J.S. [Loyola University-Chicago, Dept. or Radiation Oncology, Stritch School of Medicine, Maywood, Illinois (United States)

    2016-03-15

    A world-wide radiation health scare was created in the late 19508 to stop the testing of atomic bombs and block the development of nuclear energy. In spite of the large amount of evidence that contradicts the cancer predictions, this fear continues. It impairs the use of low radiation doses in medical diagnostic imaging and radiation therapy. This brief article revisits the second of two key studies, which revolutionized radiation protection, and identifies a serious error that was missed. This error in analyzing the leukemia incidence among the 195,000 survivors, in the combined exposed populations of Hiroshima and Nagasaki, invalidates use of the LNT model for assessing the risk of cancer from ionizing radiation. The threshold acute dose for radiation-induced leukemia, based on about 96,800 humans, is identified to be about 50 rem, or 0.5 Sv. It is reasonable to expect that the thresholds for other cancer types are higher than this level. No predictions or hints of excess cancer risk (or any other health risk) should be made for an acute exposure below this value until there is scientific evidence to support the LNT hypothesis. (author)

  13. XPS and STM study of the growth and structure of passive films in high temperature water on a nickel-base alloy

    Energy Technology Data Exchange (ETDEWEB)

    Machet, A.; Galtayries, A.; Zanna, S.; Klein, L.; Maurice, V.; Jolivet, P.; Foucault, M.; Combrade, P.; Scott, P.; Marcus, P

    2004-09-15

    The early stages of passivation in high temperature water of a nickel-chromium-iron alloy (Alloy 600) have been investigated by X-ray Photoelectron Spectroscopy (XPS) and Scanning Tunneling Microscopy (STM). The samples (polycrystal Ni-16Cr-9Fe (wt. %) and single crystal Ni-17Cr-7Fe (1 1 1)) have been exposed for short time periods (0.4-8.2 min) to high temperature (325 deg. C) and high pressure water, under controlled hydrogen pressure, in a microautoclave designed to transfer the samples from and to the XPS spectrometer without air exposure. In the early stages of oxidation of the alloy (0.4-4 min), an ultra-thin oxide layer (about 1 nm) is formed, which consists of chromium oxide (Cr{sub 2}O{sub 3}), according to the Cr 2p{sub 3/2} core level spectrum. An outer layer of Cr(OH){sub 3} with a very small amount of Ni(OH){sub 2} is also revealed by the Cr 2p{sub 3/2}, Ni 2p{sub 3/2}, and O 1s core level spectra. At this early stage, there is a temporary blocking of the growth of Cr{sub 2}O{sub 3}. For longer exposures (4-8 min), the Cr{sub 2}O{sub 3} inner layer becomes thicker, at the expense of the outer Cr(OH){sub 3} layer. This implies the transport of Cr and Ni through the oxide layer, and release of Ni{sup 2+} in the solution. The structure of the ultra-thin oxide film formed on a single crystal Ni-17Cr-7Fe(1 1 1) alloy was analysed by STM in the constant current mode; STM images reveal that, in the early stages of oxidation, the oxide is crystalline, and the observed structure is consistent with the hexagonal structure of the oxygen sub-lattice in the basal plane (0 0 0 1) of {alpha}-Cr{sub 2}O{sub 3}.

  14. The Development of an Integrated Mechanical Skill Instructional Model (IMSIM in the Secondary Technology School (STM for the Improvement of Middle Level Skilled Worker

    Directory of Open Access Journals (Sweden)

    Riyanto Riyanto

    2016-02-01

    Full Text Available This study was conducted to develop an instructional model of mechanical skill learning for the STM students to improve their cognitive, psychomotoric skills, motivation, and creativity. To develop an adequate instructional model, 15 experts were consulted. Based on the result of consultation, the model was revised. The revised model was then tried-out to 20 students of the STM Bengkulu and 17 students of the STM Curup. The result of try-out showed that the developed test items had moderate validity and reliability. The revised instructional model was applied to 25 students of the STM Bengkulu and 30 students of the STM Curup. The result of the study showed that the integrated instructional model was effective to teach mechanical skill, highly effective to increase students' motivation, and moderate to develop creativity

  15. Vibrational spectra of nanowires measured using laser doppler vibrometry and STM studies of epitaxial graphene : an LDRD fellowship report.

    Energy Technology Data Exchange (ETDEWEB)

    Biedermann, Laura Butler

    2009-09-01

    MWNTs, their vibration spectra was more extensively studied. The thermal vibration spectra of Ag{sub 2}Ga nanoneedles was measured under both ambient and low-vacuum conditions. The operational deflection shapes of the vibrating Ag{sub 2}Ga nanoneedles was also measured, allowing confirmation of the eigenmodes of vibration. The modulus of the crystalline nanoneedles was 84.3 {+-} 1.0 GPa. Gas damping is the dominate mechanism of energy loss for nanowires oscillating under ambient conditions. The measured quality factors, Q, of oscillation are in line with theoretical predictions of air damping in the free molecular gas damping regime. In the free molecular regime, Q{sub gas} is linearly proportional to the density and diameter of the nanowire and inversely proportional to the air pressure. Since the density of the Ag{sub 2}Ga nanoneedles is three times that of the MWNTs, the Ag{sub 2}Ga nanoneedles have greater Q at atmospheric pressures. Our initial measurements of Q for Ag{sub 2}Ga nanoneedles in low-vacuum (10 Torr) suggest that the intrinsic Q of these nanoneedles may be on the order of 1000. The epitaxial carbon that grows after heating (000{bar 1}) silicon carbide (SiC) to high temperatures (1450-1600) in vacuum was also studied. At these high temperatures, the surface Si atoms sublime and the remaining C atoms reconstruct to form graphene. X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) were used to characterize the quality of the few-layer graphene (FLG) surface. The XPS studies were useful in confirming the graphitic composition and measuring the thickness of the FLG samples. STM studies revealed a wide variety of nanometer-scale features that include sharp carbon-rich ridges, moire superlattices, one-dimensional line defects, and grain boundaries. By imaging these features with atomic scale resolution, considerable insight into the growth mechanisms of FLG on the carbon-face of SiC is obtained.

  16. STM study on the self-assembly of oligothiophene-based organic semiconductors

    Directory of Open Access Journals (Sweden)

    Elena Mena-Osteritz

    2011-12-01

    Full Text Available The self-assembly properties of a series of functionalized regioregular oligo(3-alkylthiophenes were investigated by using scanning tunneling microscopy (STM at the liquid–solid interface under ambient conditions. The characteristics of the 2-D crystals formed on the (0001 plane of highly ordered pyrolitic graphite (HOPG strongly depend on the length of the π-conjugated oligomer backbone, on the functional groups attached to it, and on the alkyl substitution pattern on the individual thiophene units. Theoretical calculations were performed to analyze the geometry and electronic density of the molecular orbitals as well as to analyze the intermolecular interactions, in order to obtain models of the 2-D molecular ordering on the substrate.

  17. STM visualisation of counterions and the effect of charges on self-assembled monolayers of macrocycles

    Directory of Open Access Journals (Sweden)

    Tibor Kudernac

    2011-10-01

    Full Text Available Despite their importance in self-assembly processes, the influence of charged counterions on the geometry of self-assembled organic monolayers and their direct localisation within the monolayers has been given little attention. Recently, various examples of self-assembled monolayers composed of charged molecules on surfaces have been reported, but no effort has been made to prove the presence of counterions within the monolayer. Here we show that visualisation and exact localisation of counterions within self-assembled monolayers can be achieved with scanning tunnelling microscopy (STM. The presence of charges on the studied shape-persistent macrocycles is shown to have a profound effect on the self-assembly process at the liquid–solid interface. Furthermore, preferential adsorption was observed for the uncharged analogue of the macrocycle on a surface.

  18. STM observation of a box-shaped graphene nanostructure appeared after mechanical cleavage of pyrolytic graphite

    CERN Document Server

    Lapshin, Rostislav V

    2016-01-01

    A description is given of a three-dimensional box-shaped graphene (BSG) nanostructure formed/uncovered by mechanical cleavage of highly oriented pyrolytic graphite (HOPG). The discovered nanostructure is a multilayer system of parallel hollow channels located along the surface and having quadrangular cross-section. The thickness of the channel walls/facets is approximately equal to 1 nm. The typical width of channel facets makes about 25 nm, the channel length is 390 nm and more. The investigation of the found nanostructure by means of a scanning tunneling microscope (STM) allows us to draw a conclusion that it is possible to make spatial constructions of graphene similar to the discovered one by mechanical compression, bending, splitting, and shifting graphite surface layers. The distinctive features of such constructions are the following: simplicity of the preparation method, small contact area between graphene planes and a substrate, large surface area, nanometer cross-sectional sizes of the channels, lar...

  19. The High Precision Vibration Signal Data Acquisition System Based on the STM32

    Directory of Open Access Journals (Sweden)

    Zhu Hui-Ling

    2014-06-01

    Full Text Available Vibrating wire sensors are a class of sensors that are very popular used for strain measurements of structures in buildings and civil infrastructures. The use of frequency, rather than amplitude, to convey the signal means that vibrating wire sensors are relatively resistant signal degradation from electrical noise, long cable runs, and other changes in cable resistance. This paper proposed a high precision vibration signal acquisition with storage function based on STM32 microcontroller in order to promote safety in engineering construction. The instrument designed in this paper not only can directly collect vibrating signals, but also store data into SD card and communicate with computer so as to realize the real-time monitoring from point to point.

  20. Charge dependent asphaltene adsorption onto metal substrate : electrochemistry and AFM, STM, SAM, SEM analysis

    Energy Technology Data Exchange (ETDEWEB)

    Batina, N.; Morales-Martinez, J. [Univ. Autonoma Metropolitana-Iztapalapa (Mexico). Lab. de Nanotecnologia e Ingenieria Molecular; Ivar-Andersen, S. [Technical Univ. of Denmark (Denmark). Dept. Hem. Eng; Lira-Galeana, C. [Inst. Mexicano del Petroleo, Lazaro (Mexico). Molecular Simulation Research Program; De la Cruz-Hernandez, W.; Cota-Araiza, L.; Avalos-Borja, M. [Univ. Nacional Autonoma de Mexico (Mexico)

    2008-07-01

    Asphaltenes have been identified as the main component of pipeline molecular deposits that cause plugging of oil wells. In this study, Atomic Force Microscopy (AFM), Scanning Tunneling Microscopy (STM), Scanning Auger Microprobe Spectroscopy (SAM) and Scanning Electron Microscopy (SEM) were used to characterized molecular deposits of Mexican crude oil and asphaltenes formed at a charged metal surface. The qualitative and quantitative characterization involved determining the size and shape of adsorbed molecules and aggregates, and the elemental analysis of all components in molecular films. Samples were prepared by electrolytic deposition under galvanostatic or potentiostatic conditions directly from the crude oil or asphaltene in toluene solutions. The study showed that the formation of asphaltene deposit depends on the metal substrate charge. Asphaltenes as well as crude oil readily adsorbed at the negatively charged metal surface. Two elements were present, notably carbon and sulfur. Their content ratio varied depending on the metal substrate charge.

  1. A model of heat transfer in STM-based magnetic recording on CoNi/Pt multilayers

    NARCIS (Netherlands)

    Zhang, Li; Bain, James A.; Zhu, Jian-Gang; Abelmann, Leon; Onoue, T.

    2006-01-01

    A method of heat-assisted magnetic recording (HAMR) potentially suitable for probe-based storage systems is characterized. In this work, field emission current from a scanning tunneling microscope (STM) tip is used as the heating source. Pulse voltages of 3-7 V with a duration of 500 ns were applied

  2. Hardware-Software Complex for Functional and Parametric Tests of ARM Microcontrollers STM32F1XX

    Directory of Open Access Journals (Sweden)

    Egorov Aleksey

    2016-01-01

    Full Text Available The article presents the hardware-software complex for functional and parametric tests of ARM microcontrollers STM32F1XX. The complex is based on PXI devices by National Instruments and LabVIEW software environment. Data exchange procedure between a microcontroller under test and the complex hardware is describes. Some test results are also presented.

  3. In-situ STM study of phosphate adsorption on Cu(111), Au(111) and Cu/Au(111) electrodes

    DEFF Research Database (Denmark)

    Schlaup, Christian; Horch, Sebastian

    2013-01-01

    The interaction of Cu(111), Au(111) and Cu-covered Au(111) electrodes with a neutral phosphate buffer solution has been studied by means of cyclic voltammetry (CV) and in situ electrochemical scanning tunneling microscopy (EC-STM). Under low potential conditions, both the Cu(111) and the Au(111) ...

  4. Effects of Orthographic and Phonological Word Length on Memory for Lists Shown at RSVP and STM Rates

    Science.gov (United States)

    Coltheart, Veronika; Mondy, Stephen; Dux, Paul E.; Stephenson, Lisa

    2004-01-01

    This article reports 3 experiments in which effects of orthographic and phonological word length on memory were examined for short lists shown at rapid serial visual presentation (RSVP) and short-term memory (STM) rates. Only visual-orthographic length reduced RSVP serial recall, whereas both orthographic and phonological length lowered recall for…

  5. From first to latest imaging technology: Revisiting the first mummy investigated with X-ray in 1896 by using dual-source computed tomography

    Directory of Open Access Journals (Sweden)

    Stephanie Zesch

    2016-01-01

    Conclusion: Our results highlight the enormous progress achieved form earliest to latest imaging technology for advanced mummy research using the first human mummy investigated with X-ray. With the application of DSCT, detailed knowledge regarding age at death, sex, diseases, death, and mummification of a child from Ptolemaic Egypt are revealed while considering the temporary rites of body treatment and burial for children.

  6. Fabrication and in-situ STM investigation of growth dynamics of semiconductor nanostructures grown by MBE

    Energy Technology Data Exchange (ETDEWEB)

    Borisova, Svetlana

    2012-05-23

    Modern development of information technologies requires an introduction of new fundamental concepts, in order to create more efficient devices and to decrease their size. One of the most promising ways is to increase the functionality of silicon by integrating novel materials into Si-based production. This PhD thesis reports on the fabrication and investigation of the growth of semiconductor nanostructures on Si substrates by molecular beam epitaxy (MBE). In-situ scanning tunneling microscopy (STM) is a powerful technique in order to study morphological and electronic properties of the grown structures directly under ultra high vacuum (UHV) conditions. It is shown that the combination of MBE and in-situ STM enables the study of nucleation and growth dynamics at the atomic scale. It provides us with numerous information concerning the nucleation mechanism, the growth mode of the structures, adatom kinetics, influence of the lattice mismatch between the substrate and the grown structure as well as formation and morphology of crystal defects. The first part of the thesis focuses on the experimental realization based upon an existing setup. The construction of an in-situ UHV STM compatible with the MBE cluster and the technical improvement of the STM setup are described. Subsequently, test measurements are performed on the technologically most important surfaces, Ge (100) and Si (111). The second part of the thesis is dedicated to ordered small-period arrays of self-assembled Ge quantum dots (QDs) grown on pre-patterned Si (100) substrates. Small-period Ge QD crystals are highly interesting since band structure calculations indicate coupled electronic states of the QDs in the case of the small lateral period of approximately 30 nm. Small-period hole patterns with a period of 56 nm are fabricated by e-beam lithography on Si substrates. The evolution of the hole morphology during the in-situ pre-growth annealing and the Si buffer layer growth are studied. Deposition of 5

  7. Revisiting Lambert's problem

    Science.gov (United States)

    Izzo, Dario

    2015-01-01

    The orbital boundary value problem, also known as Lambert problem, is revisited. Building upon Lancaster and Blanchard approach, new relations are revealed and a new variable representing all problem classes, under L-similarity, is used to express the time of flight equation. In the new variable, the time of flight curves have two oblique asymptotes and they mostly appear to be conveniently approximated by piecewise continuous lines. We use and invert such a simple approximation to provide an efficient initial guess to an Householder iterative method that is then able to converge, for the single revolution case, in only two iterations. The resulting algorithm is compared, for single and multiple revolutions, to Gooding's procedure revealing to be numerically as accurate, while having a significantly smaller computational complexity.

  8. Logistics Innovation Process Revisited

    DEFF Research Database (Denmark)

    Gammelgaard, Britta; Su, Shong-Iee Ivan; Yang, Su-Lan

    2011-01-01

    Purpose – The purpose of this paper is to learn more about logistics innovation processes and their implications for the focal organization as well as the supply chain, especially suppliers. Design/methodology/approach – The empirical basis of the study is a longitudinal action research project...... that was triggered by the practical needs of new ways of handling material flows of a hospital. This approach made it possible to revisit theory on logistics innovation process. Findings – Apart from the tangible benefits reported to the case hospital, five findings can be extracted from this study: the logistics...... on internal stakeholders as on external relationships; and logistics innovation process may start out as a dialectic, conflict ridden process and end up in a well-ordered goal-oriented teleological process. Research limitations/implications – In general, the study contributes to the knowledge base...

  9. Deterministic Graphical Games Revisited

    DEFF Research Database (Denmark)

    Andersson, Klas Olof Daniel; Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro

    2012-01-01

    Starting from Zermelo’s classical formal treatment of chess, we trace through history the analysis of two-player win/lose/draw games with perfect information and potentially infinite play. Such chess-like games have appeared in many different research communities, and methods for solving them......, such as retrograde analysis, have been rediscovered independently. We then revisit Washburn’s deterministic graphical games (DGGs), a natural generalization of chess-like games to arbitrary zero-sum payoffs. We study the complexity of solving DGGs and obtain an almost-linear time comparison-based algorithm...... for finding optimal strategies in such games. The existence of a linear time comparison-based algorithm remains an open problem....

  10. Automated HAZOP revisited

    DEFF Research Database (Denmark)

    Taylor, J. R.

    2017-01-01

    Hazard and operability analysis (HAZOP) has developed from a tentative approach to hazard identification for process plants in the early 1970s to an almost universally accepted approach today, and a central technique of safety engineering. Techniques for automated HAZOP analysis were developed...... in the 1970s, but still have not displaced expensive manual approaches. Reasons for this were investigated and conclusions are drawn. The author's actual experience in applying automated HAZOP techniques over a period of more than 30 years is revisited, including results from several full-scale validation...... studies and many industrial applications. Automated techniques, when combined with manual approaches, were found to provide significant improvements in HAZOP quality and a limited but valuable improvement in efficiency....

  11. Revisiting the schism.

    Science.gov (United States)

    Litsios, Socrates

    2014-01-01

    The schism between medicine and public health has deep historical roots. The Rockefeller Foundation's Clinical Epidemiology program, initiated in the late 1970s, was seen by Kerr White, its director, as the means to heal the schism. This article revisits the role that the Foundation played in creating that schism before reviewing post-World War II efforts on the part of both the Foundation and the World Health Organization to incorporate the teaching of preventive medicine in medical education curricula. White labeled these efforts as failures, but a closer look at the history raises questions concerning what evidence he used to make this judgment and whether clinical epidemiology has not instead widened the gap between cure and prevention.

  12. Reframing in dentistry: Revisited

    Directory of Open Access Journals (Sweden)

    Sivakumar Nuvvula

    2013-01-01

    Full Text Available The successful practice of dentistry involves a good combination of technical skills and soft skills. Soft skills or communication skills are not taught extensively in dental schools and it can be challenging to learn and at times in treating dental patients. Guiding the child′s behavior in the dental operatory is one of the preliminary steps to be taken by the pediatric dentist and one who can successfully modify the behavior can definitely pave the way for a life time comprehensive oral care. This article is an attempt to revisit a simple behavior guidance technique, reframing and explain the possible psychological perspectives behind it for better use in the clinical practice.

  13. Where are we? The anatomy of the murine cortical meninges revisited for intravital imaging, immunology, and clearance of waste from the brain.

    Science.gov (United States)

    Coles, Jonathan A; Myburgh, Elmarie; Brewer, James M; McMenamin, Paul G

    2017-09-01

    Rapid progress is being made in understanding the roles of the cerebral meninges in the maintenance of normal brain function, in immune surveillance, and as a site of disease. Most basic research on the meninges and the neural brain is now done on mice, major attractions being the availability of reporter mice with fluorescent cells, and of a huge range of antibodies useful for immunocytochemistry and the characterization of isolated cells. In addition, two-photon microscopy through the unperforated calvaria allows intravital imaging of the undisturbed meninges with sub-micron resolution. The anatomy of the dorsal meninges of the mouse (and, indeed, of all mammals) differs considerably from that shown in many published diagrams: over cortical convexities, the outer layer, the dura, is usually thicker than the inner layer, the leptomeninx, and both layers are richly vascularized and innervated, and communicate with the lymphatic system. A membrane barrier separates them and, in disease, inflammation can be localized to one layer or the other, so experimentalists must be able to identify the compartment they are studying. Here, we present current knowledge of the functional anatomy of the meninges, particularly as it appears in intravital imaging, and review their role as a gateway between the brain, blood, and lymphatics, drawing on information that is scattered among works on different pathologies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Absolut Revolution: Revisiting the Cuban image of the sixties (1959-1969 Absolut Revolution: Revisitando la imagen cubana de los años 60 (1959-1969

    Directory of Open Access Journals (Sweden)

    Grethel Morell Otero

    2009-04-01

    Full Text Available This paper focuses on the photographic images produced in Cuba between 1959 and 1969, analyses the formation in the advertising world for most photographers that reflect the revolution, compares their visions with the prospects offered by photographers who visited Cuba in mentioned period, traces the subsequent uses of these photos on the poster, the policy graph and international exhibitions, and puts into perspective the hegemonic historiographical discourses on the image “revolutionary.” El ensayo está enfocado sobre las imágenes fotográficas producidas en Cuba entre 1959 y 1969, analiza la formación en el mundo publicitario de la mayoría de los fotógrafos que reflejan la Revolución, compara sus visiones con las perspectivas ofrecidas por fotógrafos que visitaron Cuba en el período mencionado, traza los usos posteriores de estas fotos en el cartel, la gráfica política y las exposiciones internacionales, y sitúa en perspectiva los discursos historiográficos hegemónicos sobre la imagen “revolucionaria”.

  15. From first to latest imaging technology: Revisiting the first mummy investigated with X-ray in 1896 by using dual-source computed tomography.

    Science.gov (United States)

    Zesch, Stephanie; Panzer, Stephanie; Rosendahl, Wilfried; Nance, John W; Schönberg, Stefan O; Henzler, Thomas

    2016-01-01

    The aim of this study was to systematically reinvestigate the first human mummy that was ever analyzed with X-ray imaging in 1896, using dual-source computed tomography (DSCT) in order to compare the earliest and latest imaging technologies, to estimate preservation, age at death, sex, anatomical variants, paleopathological findings, mummification, embalming and wrapping of the child mummy from ancient Egypt. Radiocarbon dating was used to determine the mummy's age and to specify the child's living period in the Egyptian chronology. The ancient Egyptian child mummy is kept in the Senckenberg Museum of Natural History in Frankfurt am Main, Germany. An accelerator mass spectrometer (MICADAS) was used for radiocarbon dating. DSCT was performed using a 2 × 64 slice dual-source CT system (Siemens Healthineers, Forchheim, Germany). A thorough visual examination of the mummy, a systematic radiological evaluation of the DICOM datasets, and established methods in physical anthropology were applied to assess the bio-anthropological data and the post mortem treatment of the body. Radiocarbon dating yielded a calibrated age between 378 and 235 cal BC (95.4% confidence interval), corresponding with the beginning of the Ptolemaic period. The mummy was a male who was four to five years old at the time of death. Remnants of the brain and inner organs were preserved by the embalmers, which is regularly observed in ancient Egyptian child mummies. Skin tissue, inner organs, tendons and/or musculature, cartilage, nerves and vasculature could be identified on the DSCT dataset. The dental health of the child was excellent. Anatomical variants and pathological defects included a congenital Pectus excavatum deformity, hepatomegaly, Harris lines, and longitudinal clefts in the ventral cortices of both femora. Our results highlight the enormous progress achieved form earliest to latest imaging technology for advanced mummy research using the first human mummy investigated with X

  16. The Sentinel-3 Surface Topography Mission (S-3 STM): Level 2 SAR Ocean Retracker

    Science.gov (United States)

    Dinardo, S.; Lucas, B.; Benveniste, J.

    2015-12-01

    The SRAL Radar Altimeter, on board of the ESA Mission Sentinel-3 (S-3), has the capacity to operate either in the Pulse-Limited Mode (also known as LRM) or in the novel Synthetic Aperture Radar (SAR) mode. Thanks to the initial results from SAR Altimetry obtained exploiting CryoSat-2 data, lately the interest by the scientific community in this new technology has significantly increased and consequently the definition of accurate processing methodologies (along with validation strategies) has now assumed a capital importance. In this paper, we present the algorithm proposed to retrieve from S-3 STM SAR return waveforms the standard ocean geophysical parameters (ocean topography, wave height and sigma nought) and the validation results that have been so far achieved exploiting the CryoSat-2 data as well as the simulated data. The inversion method (retracking) to extract from the return waveform the geophysical information is a curve best-fitting scheme based on the bounded Levenberg-Marquardt Least-Squares Estimation Method (LEVMAR-LSE). The S-3 STM SAR Ocean retracking algorithm adopts, as return waveform’s model, the “SAMOSA” model [Ray et al, 2014], named after the R&D project SAMOSA (led by Satoc and funded by ESA), in which it has been initially developed. The SAMOSA model is a physically-based model that offers a complete description of a SAR Altimeter return waveform from ocean surface, expressed in the form of maps of reflected power in Delay-Doppler space (also known as stack) or expressed as multilooked echoes. SAMOSA is able to account for an elliptical antenna pattern, mispointing errors in roll and yaw, surface scattering pattern, non-linear ocean wave statistics and spherical Earth surface effects. In spite of its truly comprehensive character, the SAMOSA model comes with a compact analytical formulation expressed in term of Modified Bessel functions. The specifications of the retracking algorithm have been gathered in a technical document (DPM

  17. Revisiting the relationship of three-dimensional fluid attenuation inversion recovery imaging and hearing outcomes in adults with idiopathic unilateral sudden sensorineural hearing loss

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Wen-Huei [School of Medicine, National Yang Ming University, Taipei, 11221, Taiwan (China); Department of Otolaryngology, Taipei Veterans General Hospital, Taipei, 11217, Taiwan (China); Wu, Hsiu-Mei [School of Medicine, National Yang Ming University, Taipei, 11221, Taiwan (China); Department of Radiology, Taipei Veterans General Hospital, Taipei, 11217, Taiwan (China); Wu, Hung-Yi [Department of Radiology, Taipei Veterans General Hospital, Taipei, 11217, Taiwan (China); Tu, Tzong-Yang; Shiao, An-Suey [School of Medicine, National Yang Ming University, Taipei, 11221, Taiwan (China); Department of Otolaryngology, Taipei Veterans General Hospital, Taipei, 11217, Taiwan (China); Castillo, Mauricio [Department of Radiology, University of North Carolina, Chapel Hill, NC, 27599-7510 (United States); Hung, Sheng-Che, E-mail: hsz829@gmail.com [School of Medicine, National Yang Ming University, Taipei, 11221, Taiwan (China); Department of Radiology, Taipei Veterans General Hospital, Taipei, 11217, Taiwan (China); Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, 11221, Taiwan (China)

    2016-12-15

    Background and purpose: Three-dimensional fluid attenuation inversion recovery (3D FLAIR) may demonstrate high signal in the inner ears of patients with idiopathic sudden sensorineural hearing loss (ISSNHL), but the correlations of this finding with outcomes are still controversial. Here we compared 4 3D MRI sequences with the outcomes of patients with ISSNHL. Materials and methods: 77 adult patients with ISSNHL underwent MRI with pre contrast FLAIR, fast imaging employing steady-state acquisition images (FIESTA-C), post contrast T1WI and post contrast FLAIR. The extent and degree of high signal in both cochleas were evaluated in all patients, and asymmetry ratios between the affected ears and the normal ones were calculated. The relationships among MRI findings, including extent and asymmetry of abnormal cochlear high signals, degree of FLAIR enhancement, and clinical information, including age, vestibular symptoms, baseline hearing loss, and final hearing outcomes were analyzed. Results: 54 patients (28 men; age, 52.1 ± 15.5 years) were included in our study. Asymmetric cochlear signal intensities were more frequently observed in pre contrast and post contrast FLAIR (79.6% and 68.5%) than in FIESTA-C (61.1%) and T1WI (51.9%) (p < 0.001). Age, baseline hearing loss, extent of high signal and asymmetry ratios of pre contrast and post contrast FLAIR were all correlated with final hearing outcomes. In multivariate analysis, age and the extent of high signals were the most significant predictors of final hearing outcomes. Conclusion: 3D FLAIR provides a higher sensitivity in detecting the asymmetric cochlear signal abnormality. The more asymmetric FLAIR signals and presence of high signals beyond cochlea indicated a poorer prognosis.

  18. Tantalum induced butterfly-like clusters on Si (111)-7 × 7 surface: STM/STS study at low coverage

    Science.gov (United States)

    Shukrynau, Pavel; Mutombo, Pingo; Švec, Martin; Hietschold, Michael; Cháb, Vladimír

    2012-02-01

    The adsorption of the small amounts of tantalum on Si (111)-7 × 7 reconstructed surface is investigated systematically using scanning tunneling microscopy and tunneling spectroscopy combined with first-principles density functional theory calculations. We find out that the moderate annealing of the Ta covered surface results in the formation of clusters of the butterfly-like shape. The clusters are sporadically distributed over the surface and their density is metal coverage dependent. Filled and empty state STM images of the clusters differ strongly suggesting the existence of covalent bonds within the cluster. Tunneling spectroscopy measurements reveal small energy gap, showing semiconductor-like behavior of the constituent atoms. The cluster model based on experimental images and theoretical calculations has been proposed and discussed. Presented results show that Ta joins the family of adsorbates, that are known to form magic clusters on Si (111)-7 × 7, but its magic cluster has the structural and electronic properties that are different from those reported before.

  19. Lorentz violation naturalness revisited

    Energy Technology Data Exchange (ETDEWEB)

    Belenchia, Alessio; Gambassi, Andrea; Liberati, Stefano [SISSA - International School for Advanced Studies, via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste, via Valerio 2, 34127 Trieste (Italy)

    2016-06-08

    We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-energy percolation also in this case.

  20. Revisiting keratoconus diagnosis and progression classification based on evaluation of corneal asymmetry indices, derived from Scheimpflug imaging in keratoconic and suspect cases

    Directory of Open Access Journals (Sweden)

    Kanellopoulos AJ

    2013-07-01

    Full Text Available Anastasios John Kanellopoulos,1,2 George Asimellis1 1Laservision.gr Eye Institute, Athens, Greece; 2New York University School of Medicine, New York, NY, USA Purpose: To survey the standard keratoconus grading scale (Pentacam®-derived Amsler–Krumeich stages compared to corneal irregularity indices and best spectacle-corrected distance visual acuity (CDVA. Patients and methods: Two-hundred and twelve keratoconus cases were evaluated for keratoconus grading, anterior surface irregularity indices (measured by Pentacam imaging, and subjective refraction (measured by CDVA. The correlations between CDVA, keratometry, and the Scheimpflug keratoconus grading and the seven anterior surface Pentacam-derived topometric indices – index of surface variance, index of vertical asymmetry, keratoconus index, central keratoconus index, index of height asymmetry, index of height decentration, and index of minimum radius of curvature – were analyzed using paired two-tailed t-tests, coefficient of determination (r2, and trendline linearity. Results: The average ± standard deviation CDVA (expressed decimally was 0.626 ± 0.244 for all eyes (range 0.10–1.00. The average flat meridian keratometry was (K1 46.7 ± 5.89 D; the average steep keratometry (K2 was 51.05 ± 6.59 D. The index of surface variance and the index of height decentration had the strongest correlation with topographic keratoconus grading (P< 0.001. CDVA and keratometry correlated poorly with keratoconus severity. Conclusion: It is reported here for the first time that the index of surface variance and the index of height decentration may be the most sensitive and specific criteria in the diagnosis, progression, and surgical follow-up of keratoconus. The classification proposed herein may present a novel benchmark in clinical work and future studies. Keywords: diagnosis and classification, Pentacam topometric indices, Amsler–Krumeich keratoconus grading, surface variance, vertical asymmetry

  1. Anisotropic superconductivity in {beta}-(BDA-TTP){sub 2}SbF{sub 6}: STM spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, K. [Department of Physics, Hokkaido University, Sapporo 060-0810 (Japan)], E-mail: knmr@phys.sci.hokudai.ac.jp; Muraoka, R.; Matsunaga, N. [Department of Physics, Hokkaido University, Sapporo 060-0810 (Japan); Ichimura, K. [Division of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Yamada, J. [Division of Material Science, University of Hyogo, Hyogo 678-1297 (Japan)

    2009-03-01

    We have investigated the gap symmetry in the superconducting phase of {beta}-(BDA-TTP){sub 2}SbF{sub 6} with use of the scanning tunneling microscope (STM). The tunneling spectra obtained on the conducting surface show a clear superconducting gap structure. Its functional form is of V-shaped similarly to {kappa}-(BEDT-TTF){sub 2}X and suggests the anisotropic superconducting gap with line nodes. For lateral surfaces the shape of tunneling spectra varies from the U-shape with relatively large gap to the V-shape with small gap depending on the tunneling direction alternately twice between directional angle 0 and {pi}. From the analysis of conductance curve taking the k dependence of the tunneling probability into account, it is found that the gap has maximum near the a* and c* axes and the nodes appear along near a*+c* and the a-c* directions. These indicate that the d{sub x{sup 2}-y{sup 2}} like superconducting pair is formed in this system as the case of {kappa}-(BEDT-TTF){sub 2}X. This node direction is consistent with the theoretical prediction based on the spin fluctuation mechanism. However, the zero-bias conductance peak has not been observed yet.

  2. Implementasi Analog Front End Pada Sensor Kapasitif Untuk Pengaturan Kelembaban Menggunakan Mikrokontroller STM32

    Directory of Open Access Journals (Sweden)

    Rendy Setiawan

    2017-01-01

    Full Text Available Sensor kapasitif merupakan jenis sensor yang mengubah stimulus fisik menjadi perubahan kapasitansi. Pada sensor kapasitif, adanya stray capacitance atau kapasitansi parasitik pada sensor dapat menyebabkan kesalahan dalam pengukuran. Dalam aplikasi pengaturan kelembaban, dibutuhkan sistem pengukuran kelembaban dengan kesalahan minimum untuk mendapatkan nilai setting point dengan galat minimum. Maka diperlukan implementasi analog front end yang dapat meminimalisir kesalahan akibat stray capacitance pada sensor kapasitif untuk pengukuran kelembaban relatif. Pada sistem pengukuran sensor kapasitif ini, sensor dieksitasi dengan sinyal AC yang dihasilkan oleh generator sinyal pada frekuensi 10 KHz, kemudian diimplementasikan analog front end untuk mengondisikan sinyal dari sensor. Keluaran dari analog front end dikonversi menjadi sinyal DC menggunakan demodulator sinkron dan filter low pass lalu dikonversi menjadi data digital menggunakan ADC di mikrokontroller STM32. Hasil pengukuran yang didapatkan dengan implementasi analog front end kemudian kemudian gunakan untuk mengatur kelembaban pada sebuah plant growth chamber. Berdasarkan hasil dari pengujian, rangkaian analog front end dapat mengompensasi stray capacitance dengan kesalahan pembacaan nilai kapasitansi maksimal sebesar 4.2% pada kondisi stray capacitance sebesar 236,6pF, 174,3pF dan 115,7pF. Implementasi analog front end pada pengaturan kelembaban menghasilkan galat pada setting point maksimal sebesar 8.8% untuk nilai RH 75% dan 33%.

  3. Titanium dioxide surfaces and interfaces studied using ESDIAD, LEED and STM

    CERN Document Server

    Cocks, I D

    1998-01-01

    resolved into two contributions: H atoms bonded at the oxide substrate, and the rupture of the C-H bonds of the acetate. It is proposed that acetates are bridge bonded with five-fold coordinated Ti sup 4 sup + ions, with their molecular plane perpendicular to the surface. Decomposition of acetate at room temperature occurs under electron beam radiation, desorbing CH sub 2 CO and CH sub 3 /CH sub 4. Adsorption of benzoic acid at the TiO sub 2 (110) surface is dissociative, forming benzoate and surface hydroxyls. Adsorbed benzoate is bonded with the five-fold coordinated Ti sup 4 sup + cations, forming a pseudo (2x1) overlayer at a saturation coverage of 0.5 ML. Attractive interactions between benzoate aromatic rings leads to the formation of dimerised benzoate rows along the [001] direction. TiO sub 2 surfaces have been studied by electron stimulated desorption ion angular distribution (ESDIAD), low energy electron diffraction (LEED) and scanning tunnelling microscopy (STM). The TiO sub 2 (100) surface was stu...

  4. Supramolecular order and structural dynamics: A STM study of 2H-tetraphenylporphycene on Cu(111)

    Science.gov (United States)

    Stark, Michael; Träg, Johannes; Ditze, Stefanie; Brenner, Wolfgang; Jux, Norbert; Steinrück, Hans-Peter; Marbach, Hubertus

    2015-03-01

    The adsorption of 2H-tetraphenylporphycene (2HTPPc) on Cu(111) was investigated by scanning tunneling microscopy (STM). At medium coverages, supramolecular ordered islands are observed. The individual 2HTPPc molecules appear as two pairs of intense protrusions which are separated by an elongated depression. In the islands, the molecules are organized in rows oriented along one of the close packed Cu(111) substrate rows; the structure is stabilized by T-type interactions of the phenyl substituents of neighboring molecules. Two types of rows are observed, namely, highly ordered rows in which all molecules exhibit the same orientation, and less ordered rows in which the molecules exhibit two perpendicular orientations. Altogether, three different azimuthal orientations of 2HTPPc are observed within one domain, all of them rotated by 15° ± 1° relative to one closed packed Cu direction. The highly ordered rows are always separated by either one or two less ordered rows, with the latter structure being the thermodynamically more stable one. The situation in the islands is highly dynamic, such that molecules in the less ordered rows occasionally change orientation, also complete highly ordered rows can move. The supramolecular order and structural dynamics are discussed on the basis of the specific molecule-substrate and molecule-molecule interactions.

  5. The "Mushroom Cloud" Demonstration Revisited

    Science.gov (United States)

    Panzarasa, Guido; Sparnacci, Katia

    2013-01-01

    A revisitation of the classical "mushroom cloud" demonstration is described. Instead of aniline and benzoyl peroxide, the proposed reaction involves household chemicals such as alpha-pinene (turpentine oil) and trichloroisocyanuric acid ("Trichlor") giving an impressive demonstration of oxidation and combustion reactions that…

  6. Leadership and Management Theories Revisited

    DEFF Research Database (Denmark)

    Madsen, Mona Toft

    2001-01-01

    The goal of the paper is to revisit and analyze key contributions to the understanding of leadership and management. As a part of the discussion a role perspective that allows for additional and/or integrated leader dimensions, including a change-centered, will be outlined. Seemingly, a major...

  7. Revisiting Inter-Genre Similarity

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Gouyon, Fabien

    2013-01-01

    We revisit the idea of ``inter-genre similarity'' (IGS) for machine learning in general, and music genre recognition in particular. We show analytically that the probability of error for IGS is higher than naive Bayes classification with zero-one loss (NB). We show empirically that IGS does...

  8. A remote coal deposit revisited

    DEFF Research Database (Denmark)

    Bojesen-Kofoed, Jørgen A.; Kalkreuth, Wolfgang; Petersen, Henrik I.

    2012-01-01

    In 1908, members of the “Danmark Expedition” discovered a coal deposit in a very remote area in western Germania Land, close to the margin of the inland ice in northeast Greenland. The deposit was, however, neither sampled nor described, and was revisited in 2009 for the first time since its...

  9. Benjamin Franklin and Mesmerism, revisited.

    Science.gov (United States)

    McConkey, Kevin M; Perry, Campbell

    2002-10-01

    The authors revisit and update their previous historiographical note (McConkey & Perry, 1985) on Benjamin Franklin's involvement with and investigation of animal magnetism or mesmerism. They incorporate more recent literature and offer additional comment about Franklin's role in and views about mesmerism. Franklin had a higher degree of personal involvement with and a more detailed opinion of mesmerism than has been previously appreciated.

  10. Classical electricity analysis of the coupling mechanisms between admolecule vibrations and localized surface plasmons in STM for vibration detectability

    Science.gov (United States)

    Inaoka, Takeshi; Uehara, Yoich

    2017-08-01

    The presence of a dynamic dipole moment in the gap between the tip of a scanning tunneling microscope (STM) and a substrate, both of which are made of metal, produces a large dynamic dipole moment via the creation of localized surface plasmons (LSPLs). With regard to the vibration-induced structures that have been experimentally observed in STM light emission spectra, we have incorporated the effect of the phonon vibrations of an admolecule below the STM tip into the local response theory, and we have evaluated the enhancement of the dynamic dipole involving phonon vibrations. Our analysis shows how effectively this vibration becomes coupled with the LSPLs. This was shown using three mechanisms that considered the vibrations of a dipole-active molecule and the vibrations of a charged molecule emitting and receiving tunneling electrons. In each of the mechanisms, phonon vibrations with angular frequency ωp shifted each LSPL resonance by ℏωp or by a multiple of ℏωp . The phonon effect was negligibly small when the position of the dipole-active molecule vibrated with ωp, but it was largest and most detectable when the point charge corresponding to the admolecule at the surface of the tip vibrated with ωp. It was found that a series of LSPL resonances with or without phonon-energy shifts can be characterized by a few dominant orders of multipole excitations, and these orders become higher as the resonance energy increases.

  11. Adsorption of the ionic liquid [BMP][TFSA] on Au(111 and Ag(111: substrate effects on the structure formation investigated by STM

    Directory of Open Access Journals (Sweden)

    Benedikt Uhl

    2013-12-01

    Full Text Available In order to resolve substrate effects on the adlayer structure and structure formation and on the substrate–adsorbate and adsorbate–adsorbate interactions, we investigated the adsorption of thin films of the ionic liquid (IL 1-butyl-1-methylpyrrolidinium-bis(trifluoromethylsulfonylimide [BMP][TFSA] on the close-packed Ag(111 and Au(111 surfaces by scanning tunneling microscopy, under ultra high vacuum (UHV conditions in the temperature range between about 100 K and 293 K. At room temperature, highly mobile 2D liquid adsorbate phases were observed on both surfaces. At low temperatures, around 100 K, different adsorbed IL phases were found to coexist on these surfaces, both on silver and gold: a long-range ordered (‘2D crystalline’ phase and a short-range ordered (‘2D glass’ phase. Both phases exhibit different characteristics on the two surfaces. On Au(111, the surface reconstruction plays a major role in the structure formation of the 2D crystalline phase. In combination with recent density functional theory calculations, the sub-molecularly resolved STM images allow to clearly discriminate between the [BMP]+ cation and [TFSA]− anion.

  12. Revisiting the Yummy Mummy

    DEFF Research Database (Denmark)

    Nikolajsen, Helene; Prinds, Christina Lange; Folmann, Birgitte

    2016-01-01

    To explore Danish new fathers’ perceptions of their partners’ post partum body and how fathers’ perspective influence the post partum body identity and body image of the new mother.......To explore Danish new fathers’ perceptions of their partners’ post partum body and how fathers’ perspective influence the post partum body identity and body image of the new mother....

  13. Revisiting the Yummy Mummy

    DEFF Research Database (Denmark)

    Prinds, Christina; Folmann, Birgitte; Nikolajsen, Helene

    To explore Danish new fathers’ perceptions of their partners’ post partum body and how fathers’ perspective influence the post partum body identity and body image of the new mother.......To explore Danish new fathers’ perceptions of their partners’ post partum body and how fathers’ perspective influence the post partum body identity and body image of the new mother....

  14. Remembered Experiences and Revisit Intentions

    DEFF Research Database (Denmark)

    Barnes, Stuart; Mattsson, Jan; Sørensen, Flemming

    2016-01-01

    Tourism is an experience-intensive sector in which customers seek and pay for experiences above everything else. Remembering past tourism experiences is also crucial for an understanding of the present, including the predicted behaviours of visitors to tourist destinations. We adopt a longitudinal...... approach to memory data collection from psychological science, which has the potential to contribute to our understanding of tourist behaviour. In this study, we examine the impact of remembered tourist experiences in a safari park. In particular, using matched survey data collected longitudinally and PLS...... path modelling, we examine the impact of positive affect tourist experiences on the development of revisit intentions. We find that longer-term remembered experiences have the strongest impact on revisit intentions, more so than predicted or immediate memory after an event. We also find that remembered...

  15. Leadership and Management Theories Revisited

    OpenAIRE

    Madsen, Mona Toft

    2001-01-01

    The goal of the paper is to revisit and analyze key contributions to the understanding of leadership and management. As a part of the discussion a role perspective that allows for additional and/or integrated leader dimensions, including a change-centered, will be outlined. Seemingly, a major challenge on the substantive level is the integration of soft and hard managerial functions, while the concepts used in presenting these should at least in transition be able to contain a distinction bet...

  16. Revisiting Nursing Research in Nigeria

    OpenAIRE

    Emelonye A.U; Pitkäaho T; Aregbesola A; Vehviläinen- Julkunen K

    2016-01-01

    Background: Evidence from a nursing conference convened in Nigeria in 1973 amongst other things implied that Nigerian nurses are not adequately educated and ill-equipped with prerequisite research skills. Four decades after the first and only initiative that examined the capacity and contribution of Nigerian Nurses to health care research, it is therefore pertinent to revisit the state of nursing research in the country. Aim: To review the academic and research preparedness of ...

  17. Nuclear fear revisited

    Science.gov (United States)

    Crease, Robert P.

    2010-10-01

    In 1988 the science historian Spencer Weart published a groundbreaking book called Nuclear Fear: A History of Images, which examined visions of radiation damage and nuclear disaster in newspapers, television, film, literature, advertisements and popular culture.

  18. Binocularity and visual search-Revisited.

    Science.gov (United States)

    Zou, Bochao; Utochkin, Igor S; Liu, Yue; Wolfe, Jeremy M

    2017-02-01

    Binocular rivalry is a phenomenon of visual competition in which perception alternates between two monocular images. When two eye's images only differ in luminance, observers may perceive shininess, a form of rivalry called binocular luster. Does dichoptic information guide attention in visual search? Wolfe and Franzel (Perception & Psychophysics, 44(1), 81-93, 1988) reported that rivalry could guide attention only weakly, but that luster (shininess) "popped out," producing very shallow Reaction Time (RT) × Set Size functions. In this study, we have revisited the topic with new and improved stimuli. By using a checkerboard pattern in rivalry experiments, we found that search for rivalry can be more efficient (16 ms/item) than standard, rivalrous grating (30 ms/item). The checkerboard may reduce distracting orientation signals that masked the salience of rivalry between simple orthogonal gratings. Lustrous stimuli did not pop out when potential contrast and luminance artifacts were reduced. However, search efficiency was substantially improved when luster was added to the search target. Both rivalry and luster tasks can produce search asymmetries, as is characteristic of guiding features in search. These results suggest that interocular differences that produce rivalry or luster can guide attention, but these effects are relatively weak and can be hidden by other features like luminance and orientation in visual search tasks.

  19. Hybrid image potential states in molecular overlayers on graphene

    Science.gov (United States)

    Wella, Sasfan Arman; Sawada, Hiroyuki; Kawaguchi, Nana; Muttaqien, Fahdzi; Inagaki, Kouji; Hamada, Ikutaro; Morikawa, Yoshitada; Hamamoto, Yuji

    2017-11-01

    The structural and electronic properties of naphthalene adsorbed on graphene are studied from first principles using the van der Waals density functional method. It is shown that naphthalene molecules are stabilized by forming a superstructure with the periodicity of (2 √{3 }×2 √{3 }) and a tilted molecular adsorption geometry on graphene, in good agreement with the scanning tunneling microscopy (STM) experiments on highly oriented pyrolytic graphite. Our results predict that image potential states (IPSs) are induced by intermolecular interaction on the naphthalene overlayer, hybridizing with the IPSs derived from graphene. The resultant hybrid IPSs are characterized by anisotropic effective mass reflecting the molecular structure of naphthalene. By means of STM simulations, we reveal that one of the hybrid IPSs manifests itself as an oval protrusion distinguishable from naphthalene molecular orbitals, which identifies the origin of an experimental STM image previously attributed to the lowest unoccupied molecular orbital of naphthalene.

  20. Bi surfactant mediated growth for fabrication of Si/Ge nanostructures and investigation of Si/Ge intermixing by STM

    Energy Technology Data Exchange (ETDEWEB)

    Paul, N.

    2007-10-26

    In the thesis work presented here, we show that Bi is more promising surfactant material than Sb. We demonstrate that by using Bi as a terminating layer on Ge/Si surface, it is possible to distinguish between Si and Ge in Scanning tunnelling microscope (STM). Any attempt to utilize surfactant mediated growth must be preceded by a thorough study of its effect on the the system being investigated. Thus, the third chapter of this thesis deals with an extensive study of the Bi surfactant mediated growth of Ge on Si(111) surface as a function of Ge coverage. The growth is investigated from the single bilayer Ge coverage till the Ge coverage of about 15 BL when the further Ge deposition leads to two-dimensional growth. In the fourth chapter, the unique property of Bi terminating layer on Ge/Si surface to result in an STM height contrast between Si and Ge is explained with possible explanations given for the reason of this apparent height contrast. The controlled fabrication of Ge/Si nanostructures such as nanowires and nanorings is demonstrated. A study on Ge-Si diffusion in the surface layers by a direct method such as STM was impossible previously because of the similar electronic structure of Ge and Si. Since with the Bi terminating surface layer, one is able to distinguish between Ge and Si, the study of intermixing between them is also possible using STM. This method to distinguish between Si and Ge allows one to study intermixing on the nanoscale and to identify the fundamental diffusion processes giving rise to the intermixing. In Chapter 5 we discuss how this could prove useful especially as one could get a local probe over a very narrow Ge-Si interface. A new model is proposed to estimate change in the Ge concentration in the surface layer with time. The values of the activation energies of Ge/Si exchange and Si/Ge exchange are estimated by fitting the experimental data with the model. The Ge/Si intermixing has been studied on a surface having 1 ML Bi ({radical

  1. A previously uncharacterized gene stm0551 plays a repressive role in the regulation of type 1 fimbriae in Salmonella enterica serotype Typhimurium

    Directory of Open Access Journals (Sweden)

    Wang Ke-Chuan

    2012-06-01

    Full Text Available Abstract Background Salmonella enterica serotype Typhimurium produces surface-associated fimbriae that facilitate adherence of the bacteria to a variety of cells and tissues. Type 1 fimbriae with binding specificity to mannose residues are the most commonly found fimbrial type. In vitro, static-broth culture favors the growth of S. Typhimurium with type 1 fimbriae, whereas non-type 1 fimbriate bacteria are obtained by culture on solid-agar media. Previous studies demonstrated that the phenotypic expression of type 1 fimbriae is the result of the interaction and cooperation of the regulatory genes fimZ, fimY, fimW, and fimU within the fim gene cluster. Genome sequencing revealed a novel gene, stm0551, located between fimY and fimW that encodes an 11.4-kDa putative phosphodiesterase specific for the bacterial second messenger cyclic-diguanylate monophosphate (c-di-GMP. The role of stm0551 in the regulation of type 1 fimbriae in S. Typhimurium remains unclear. Results A stm0551-deleted stain constructed by allelic exchange constitutively produced type 1 fimbriae in both static-broth and solid-agar medium conditions. Quantative RT-PCR revealed that expression of the fimbrial major subunit gene, fimA, and one of the regulatory genes, fimZ, were comparably increased in the stm0551-deleted strain compared with those of the parental strain when grown on the solid-agar medium, a condition that normally inhibits expression of type 1 fimbriae. Following transformation with a plasmid possessing the coding sequence of stm0551, expression of fimA and fimZ decreased in the stm0551 mutant strain in both culture conditions, whereas transformation with the control vector pACYC184 relieved this repression. A purified STM0551 protein exhibited a phosphodiesterase activity in vitro while a point mutation in the putative EAL domain, substituting glutamic acid (E with alanine (A, of STM0551 or a FimY protein abolished this activity. Conclusions The finding that the

  2. Unexpected deformations induced by surface interaction and chiral self-assembly of Co(II)-tetraphenylporphyrin (Co-TPP) adsorbed on Cu(110): a combined STM and periodic DFT study.

    Science.gov (United States)

    Donovan, Philip; Robin, Abel; Dyer, Matthew S; Persson, Mats; Raval, Rasmita

    2010-10-11

    In a combined scanning tunnelling microscopy (STM) and periodic density functional theory (DFT) study, we present the first comprehensive picture of the energy costs and gains that drive the adsorption and chiral self-assembly of highly distorted Co(II)-tetraphenylporphyrin (Co-TPP) conformers on the Cu(110) surface. Periodic, semi-local DFT calculations reveal a strong energetic preference for Co-TPP molecules to adsorb at the short-bridge site when organised within a domain. At this adsorption site, a substantial chemical interaction between the molecular core and the surface causes the porphyrin macrocycle to accommodate close to the surface and in a flat geometry, which induces considerable tilting distortions in the phenyl groups. Experimental STM images can be explained in terms of these conformational changes and adsorption-induced electronic effects. For the ordered structure we unambiguously show that the substantial energy gain from the molecule–surface interaction recuperates the high cost of the induced molecular and surface deformations as compared with gas phase molecules. Conversely, singly adsorbed molecules prefer a long-bridge adsorption site and adopt a non-planar, saddle-shape conformation. By using a van der Waals density functional correction scheme, we found that the intermolecular π–π interactions make the distorted conformer more stable than the saddle conformer within the organic assembly. These interactions drive supramolecular assembly and also generate chiral expression in the system, pinning individual molecules in a propeller-like conformation and directing their assembly along non-symmetric directions that lead to the coexistence of mirror-image chiral domains. Our observations reveal that a strong macrocycle–surface interaction can trigger and stabilise highly unexpected deformations of the molecular structure and thus substantially extend the range of chemistries possible within these systems. Copyright © 2010 WILEY

  3. Images

    Data.gov (United States)

    National Aeronautics and Space Administration — Images for the website main pages and all configurations. The upload and access points for the other images are: Website Template RSW images BSCW Images HIRENASD...

  4. MEG source detection revisited

    Science.gov (United States)

    Lei, Tianhu; Roberts, Timothy P. L.

    2010-04-01

    Magnetoencephalography (MEG) is a multi-channel imaging technique. It uses an array composed of a large number of Superconducting Quantum Interference Device (SQUID) to measure the magnetic fields produced by the primary electric currents inside the brain. The measured spatio-temporal magnetic fields are then used to estimate the locations and strengths of these electric currents, often known as MEG sources. The estimated quantities are finally superimposed with the images generated by magnetic resonance imaging (MRI). The combination of information from MEG and MRI forms the magnetic source image (MSI). A great variety of signal processing and modeling techniques such as Inverse problem, Subspace approach, Independent component analysis (ICA) method, and Beamforming (BF) are used to estimate these sources. The first three approaches require the number of sources be detected a priori. Several shortcomings exist in the currently used methods for detecting the source number. First, the source detection is completed only after - not before - MSI is generated. Secondly, the detection methods are somewhat subjective. In order to provide a solution to the problem of detecting MEG source number for all these approaches, a novel method is developed. The covariance matrix of MEG measurements over all channels is decomposed into the signal and the noise subspaces. The number of sources is shown to be equal to the dimension of the signal subspace. The selection of this dimension is translated into a problem of determining the order of the underlying statistics. This statistical identification is resolved by using Information theoretic criteria which are derived based on Kullback-Leibler divergence. Because the method utilizes originally acquired MEG measurements and implemented before magnetic source images are generated, it is an entirely data-driven approach, more efficient, and less likely to be subjective.

  5. Current oscillations in ultra-small superconducting Nb-Nb junctions formed by STM at mK temperatures

    Science.gov (United States)

    Dreyer, Michael; Roychowdhury, Anita; Dana, Rami

    2014-03-01

    Using etched Nb STM tips we formed ultra-small tunnel junctions on a Nb crystal at an effective temperature of ~ 200 mK using an Oxford dilution refrigerator. The Nb crystal was prepared in UHV and then transferred into the mK STM. The resulting superconductor-insulator-superconductor (SIS) junction displayed several sub-gap features from multiple Andreev reflections to a zero bias conductance peak. The latter showed features of a Josephson junction in the phase diffusion limit with side structures due to the electrical environment. Upon microwave irradiation the peak split into multiple peaks in accordance with theory, verifying Josephson tunneling. In addition we observed bias dependent oscillations of the tunneling current. The oscillations where recorded at a rate of 10 kS/s while acquiring conventional dI/dV or I(V) spectroscopic curves. Histograms of the current for each bias voltage step then reveal the nature of the oscillation. It ranges from multiple states in certain bias regions through pure oscillations to supercurrent-normal switching. Fourier transform of the current show in some cases a bias dependence of the main frequencies. Possible causes will be discussed.

  6. Mn$_3$O$_4$(001) film growth on Ag(001) - a systematic study using NEXAFS, STM, and LEED

    CERN Document Server

    Gillmeister, Konrad; Shantyr, Roman; Trautmann, Martin; Meinel, Klaus; Chassé, Angelika; Schindler, Karl-Michael; Neddermeyer, Henning; Widdra, Wolf

    2015-01-01

    The film growth of Mn$_3$O$_4$(001) films on Ag(001) up to film thicknesses of almost seven unit cells of Mn$_3$O$_4$ has been monitored using a complementary combination of near-edge X-ray absorption fine structure spectroscopy (NEXAFS), scanning tunneling microscopy (STM), and low-energy electron diffraction (LEED). The oxide films have been prepared by molecular beam epitaxy. Using NEXAFS, the identity of the Mn oxide has clearly been determined as Mn$_3$O$_4$. For the initial stages of growth, oxide islands with p(2$\\times$1) and p(2$\\times$2) structures are formed, which are embedded into the substrate. For Mn$_3$O$_4$ coverages up to 1.5 unit cells a p(2$\\times$1) structure of the films is visible in STM and LEED. Further increase of the thickness leads to a phase transition of the oxide films resulting in an additional c(2$\\times$2) structure with a 45$^\\circ$ rotated atomic pattern. The emerging film structures are discussed on the basis of a sublayer model of the Mn$_3$O$_4$ spinel unit cell. While t...

  7. A new recipe for preparing oxidized TiO2(1 1 0) surfaces: An STM study

    Science.gov (United States)

    Hansen, Jonas Ø.; Matthiesen, Jesper; Lira, Estephania; Lammich, Lutz; Wendt, Stefan

    2017-12-01

    Using high-resolution scanning tunneling microscopy (STM), we have studied the oxidation of rutile TiO2(1 1 0)-(1 × 1) surfaces with Had species at room temperature. We followed the evolution of various stable species as function of the O2 exposure, and the nature of the ultimately dominating species in the Ti troughs is described. When O2 saturation was accomplished using a glass-capillary array doser, we found that on-top O (Oot) adatoms are the predominant surface species. In contrast, when O2 was supplied via backfilling of the chamber the predominant surface species are tentatively assigned to terminal OH groups. We argue that unintended reactions with the chamber walls have a strong influence on the formed surface species, explaining scattered results in the literature. On the basis of our STM data we propose an alternative, easy way of preparing oxidized TiO2(1 1 0) surfaces with Oot adatoms (o-TiO2). It is certain that o-TiO2(1 1 0) surfaces prepared according to this recipe do not have any residual surface O vacancies. This contradicts the situation when oxidizing reduced TiO2(1 1 0) surfaces with O vacancies, where some O vacancies persist.

  8. Repositorien: Der grüne Weg zu Open Access Publishing aus der Perspektive der International Association of Scientific, Technical & Medical Publishers (STM: 10 Fragen von Bruno Bauer an Barbara Kalumenos, Director of Public Affairs bei STM / Repository: The Green Road to Open Access Publishing and the International Association of Scientific, Technical & Medical Publishers' (STM point of view: 10 questions to Barbara Kalumenos, Director of Public Affairs at STM, by Bruno Bauer

    Directory of Open Access Journals (Sweden)

    Bauer, Bruno

    2009-06-01

    Full Text Available Advocates of Open Access call to substitute the established scholarly publication model, in particular subscriptions and licences, by an Open Access Publishing model. Scholarly papers should be immediately accessible without paying and leave the copyright to the author.At the beginning the Open Access movement focused on and demanded for the publication of original scientific articles in Open Access journals. Meanwhile they moved on to support a form of secondary publication, the self-archiving of sholarly papers in institutional repositories. The current interview with Barbara Kalumenos gives an account of the International Association of Scientific, Technical & Medical Publishers (STM; http://www.stm-assoc.org/ and their point of view towards Open Access. The interview hits the Golden Road as well as the Green Road to open access and their costs. Preconditions for a paradigm shift towards Open Access Publishing are brought up and prospects of sholarly publishing in 2020 were discussed with a look on libraries and their possible role within this setting.

  9. Análisis de la Transmisión de Tramas STM-N sobre un Enlace de Fibra Óptica DWDM

    Directory of Open Access Journals (Sweden)

    Julio C. Agudelo-Ramirez

    2010-12-01

    Full Text Available In this work, we present an analysis of physical layer performance of a DWDM-link of 66 km of single-mode optical fiber on which is implemented a SDH system to send STM-1 at 155 Mbps. We show the computational simulation in Optisystem 7.0 (Evaluation Version to analyze the DWDM system characteristic at 2.5 Gbps equivalent to a STM-16 frame. The results of the eye diagram and BER show that is possible to distinguish between bits when the detector thermal-noise is less than 1x10-19 W/Hz. We analyze experimental measurements of jitter and its corresponding comparison with the value normalized by the ITU-T for a STM-1 frame. The use of more wavelengths is proposed to maximize the transmission capacity of fiber optics or installation of interfaces with high capacity for increasing the available bandwidth.

  10. Knowledge Extraction from Atomically Resolved Images.

    Science.gov (United States)

    Vlcek, Lukas; Maksov, Artem; Pan, Minghu; Vasudevan, Rama K; Kalinin, Sergei V

    2017-10-24

    Tremendous strides in experimental capabilities of scanning transmission electron microscopy and scanning tunneling microscopy (STM) over the past 30 years made atomically resolved imaging routine. However, consistent integration and use of atomically resolved data with generative models is unavailable, so information on local thermodynamics and other microscopic driving forces encoded in the observed atomic configurations remains hidden. Here, we present a framework based on statistical distance minimization to consistently utilize the information available from atomic configurations obtained from an atomically resolved image and extract meaningful physical interaction parameters. We illustrate the applicability of the framework on an STM image of a FeSe x Te 1-x superconductor, with the segregation of the chalcogen atoms investigated using a nonideal interacting solid solution model. This universal method makes full use of the microscopic degrees of freedom sampled in an atomically resolved image and can be extended via Bayesian inference toward unbiased model selection with uncertainty quantification.

  11. Cube search, revisited

    Science.gov (United States)

    Zhang, Xuetao; Huang, Jie; Yigit-Elliott, Serap; Rosenholtz, Ruth

    2015-01-01

    Observers can quickly search among shaded cubes for one lit from a unique direction. However, replace the cubes with similar 2-D patterns that do not appear to have a 3-D shape, and search difficulty increases. These results have challenged models of visual search and attention. We demonstrate that cube search displays differ from those with “equivalent” 2-D search items in terms of the informativeness of fairly low-level image statistics. This informativeness predicts peripheral discriminability of target-present from target-absent patches, which in turn predicts visual search performance, across a wide range of conditions. Comparing model performance on a number of classic search tasks, cube search does not appear unexpectedly easy. Easy cube search, per se, does not provide evidence for preattentive computation of 3-D scene properties. However, search asymmetries derived from rotating and/or flipping the cube search displays cannot be explained by the information in our current set of image statistics. This may merely suggest a need to modify the model's set of 2-D image statistics. Alternatively, it may be difficult cube search that provides evidence for preattentive computation of 3-D scene properties. By attributing 2-D luminance variations to a shaded 3-D shape, 3-D scene understanding may slow search for 2-D features of the target. PMID:25780063

  12. Penile Doppler ultrasonography revisited

    Directory of Open Access Journals (Sweden)

    Dae Chul Jung

    2018-01-01

    Full Text Available Penile Doppler ultrasonography is a high-performing, noninvasive or minimally-invasive imaging modality that allows the depiction of the normal anatomy and macroscopic pathologic changes in real time. Moreover, functional changes in penile blood flow, as seen in erectile dysfunction (ED, can be analyzed using color Doppler ultrasonography (CDUS. This review article describes the normal sonographic anatomy of the penis, the sonographic technique for evaluating ED, the normal phases of erection, and the various causes of ED. Additionally, we describe the interpretation of different parameters and findings on penile CDUS for the diagnosis and classification of ED, priapism, and Peyronie disease.

  13. Wire chambers revisited.

    Science.gov (United States)

    Ott, R J

    1993-04-01

    Detectors used for radioisotope imaging have, historically, been based on scintillating crystal/photomultiplier combinations in various forms. From the rectilinear scanner through to modern gamma cameras and positron cameras, the basic technology has remained much the same. Efforts to overcome the limitations of this form of technology have foundered on the inability to reproduce the required sensitivity, spatial resolution and sensitive area at acceptable cost. Multiwire proportional chambers (MWPCs) have long been used as position-sensitive charged particle detectors in nuclear and high-energy physics. MWPCs are large-area gas-filled ionisation chambers in which large arrays of fine wires are used to measure the position of ionisation produced in the gas by the passage of charged particles. The important properties of MWPCs are high-spatial-resolution, large-area, high-count-rate performance at low cost. For research applications, detectors several metres square have been built and small-area detectors have a charged particle resolution of 0.4 mm at a count rate of several million per second. Modification is required to MWPCs for nuclear medicine imaging. As gamma rays or X-rays cannot be detected directly, they must be converted into photo- or Compton scatter electrons. Photon-electron conversion requires the use of high atomic number materials in the body of the chamber. Pressurised xenon is the most useful form of "gas only" photon-electron convertor and has been used successfully in a gamma camera for the detection of gamma rays at energies below 100 keV. This camera has been developed specifically for high-count-rate first-pass cardiac imaging. This high-pressure xenon gas MWPC is the key to a highly competitive system which can outperform scintillator-based systems. The count rate performance is close to a million counts per second and the intrinsic spatial resolution is better than the best scintillator-based camera. The MWPC camera produces quantitative

  14. CORPORATIONS AND THE 99%: TEAM PRODUCTION REVISITED

    National Research Council Canada - National Science Library

    Shlomit Azgad-Tromer

    2015-01-01

    .... Revisiting team production analysis, this Article redefines the corporate team and argues that while several constituencies indeed form part of the corporate team, others are exogenous to the corporate enterprise...

  15. Stereo Hysteresis Revisited

    Directory of Open Access Journals (Sweden)

    Christopher Tyler

    2012-05-01

    Full Text Available One of the most fascinating phenomena in stereopsis is the profound hysteresis effect reported by Fender and Julesz (1967, in which the depth percept persisted with increasing disparity long past the point at which depth was recovered with decreasing disparity. To control retinal disparity without vergence eye movements, they stabilized the stimuli on the retinas with an eye tracker. I now report that stereo hysteresis can be observed directly in printed stereograms simply by rotating the image. As the stereo image rotates, the horizontal disparities rotate to become vertical, then horizontal with inverted sign, and then vertical again before returning to the original orientation. The depth shows an interesting popout effect, almost as though the depth was turning on and off rapidly, despite the inherently sinusoidal change in the horizontal disparity vector. This stimulus was generated electronically in a circular format so that the random-dot field could be dynamically replaced, eliminating any cue to cyclorotation. Noise density was scaled with eccentricity to fade out the stimulus near fixation. For both the invariant and the dynamic noise, profound hysteresis of several seconds delay was found in six observers. This was far longer than the reaction time to respond to changes in disparity, which was less than a second. Purely horizontal modulation of disparity to match the horizontal vector component of the disparity rotation did not show the popout effect, which thus seems to be a function of the interaction between horizontal and vertical disparities and may be attributable to depth interpolation processes.

  16. Revisiting Risk in the 21st Century. Forum Focus. Volume 3, Issue 1, January-February 2005

    Science.gov (United States)

    Forum for Youth Investment, 2005

    2005-01-01

    Over the past year, dozens of articles have been published about excessive youth borrowing and spending (leading to high amounts of debt), new reactions to negative body image (such as plastic surgery), as well as more familiar risks like premarital sex and smoking. In Forum Focus: Revisiting Risk in the 21st Century, we explore these challenges…

  17. Electric field effects in scanning tunneling microscope imaging

    DEFF Research Database (Denmark)

    Stokbro, Kurt; Quaade, Ulrich; Grey, Francois

    1998-01-01

    We present a high-voltage extension of the Tersoff-Hamann theory of scanning tunneling microscope (STM) images, which includes the effect of the electric field between the tip and the sample. The theoretical model is based on first-principles electronic structure calculations and has no adjustable...

  18. New approach towards imaging λ-DNA using scanning tunneling ...

    Indian Academy of Sciences (India)

    Wintec

    Abstract. A new methodology to anchor λ-DNA to silanized n-Si(111) surface using Langmuir Blodget trough was developed. The n-Si (111) was silanized by treating it with low molecular weight octyltrichlorosi- lane in toluene. Scanning tunneling microscopy (STM) image of λ-DNA on octyltrichlorosilane deposited Si.

  19. New approach towards imaging λ-DNA using scanning tunneling ...

    Indian Academy of Sciences (India)

    A new methodology to anchor -DNA to silanized -Si(111) surface using Langmuir Blodget trough was developed. The -Si (111) was silanized by treating it with low molecular weight octyltrichlorosilane in toluene. Scanning tunneling microscopy (STM) image of -DNA on octyltrichlorosilane deposited Si substrate ...

  20. The furcal nerve revisited

    Directory of Open Access Journals (Sweden)

    Nanjundappa S. Harshavardhana

    2014-10-01

    Full Text Available Atypical sciatica and discrepancy between clinical presentation and imaging findings is a dilemma for treating surgeon in management of lumbar disc herniation. It also constitutes ground for failed back surgery and potential litigations thereof. Furcal nerve (Furcal = forked is an independent nerve with its own ventral and dorsal branches (rootlets and forms a link nerve that connects lumbar and sacral plexus. Its fibers branch out to be part of femoral and obturator nerves in-addition to the lumbosacral trunk. It is most commonly found at L4 level and is the most common cause of atypical presentation of radiculopathy/sciatica. Very little is published about the furcal nerve and many are unaware of its existence. This article summarizes all the existing evidence about furcal nerve in English literature in an attempt to create awareness and offer insight about this unique entity to fellow colleagues/ professionals involved in spine care.

  1. Electronic structure and properties of highly ordered C60 nano arrays on Au (111): STM & DFT study

    Science.gov (United States)

    Win, Zaw-Myo; HUANG, Chao; ZHANG, Rui-Qin

    2017-06-01

    Template assisted assembly of molecular nano arrays is one of the key steps towards molecular electronics and fullerene is one of the potential structural building blocks in fabrication of identical molecular nano arrays for miniature devices such as photovoltaic devices and single-molecule transistors. In this report, the reconstructed Au (111) with defect areas (steps) has been used as a template to assemble the highly ordered C60 nano array at low coverage studied with scanning tunnelling microscopy (STM) in conjunction with density functional theory (DFT). The interaction between the substrate and C60 nano arrays is strong enough to change the geometrical shape of C60. As a result of strong interaction, the C60 molecule appears to be deformed into ellipsoidal shape which causes the reduction of C60 nano arrays on step sites of Au (111).

  2. Ordering of Zn-centered porphyrin and phthalocyanine on TiO2(011: STM studies

    Directory of Open Access Journals (Sweden)

    Piotr Olszowski

    2017-01-01

    Full Text Available Zn(IIphthalocyanine molecules (ZnPc were thermally deposited on a rutile TiO2(011 surface and on Zn(IImeso-tetraphenylporphyrin (ZnTPP wetting layers at room temperature and after elevated temperature thermal processing. The molecular homo- and heterostructures were characterized by high-resolution scanning tunneling microscopy (STM at room temperature and their geometrical arrangement and degree of ordering are compared with the previously studied copper phthalocyanine (CuPc and ZnTPP heterostructures. It was found that the central metal atom may play some role in ordering and growth of phthalocyanine/ZnTPP heterostructures, causing differences in stability of upright standing ZnPc versus CuPc molecular chains at given thermal annealing conditions.

  3. Use of Local Electrochemical Methods (SECM, EC-STM) and AFM to Differentiate Microstructural Effects (EBSD) on Very Pure Copper

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Lombardia, Esther; Graeve, Iris De; Terryn, Herman [Vrije Universiteit Brussel, Brussels (Belgium); Lapeire, Linsey; Verbeken, Kim; Kestens, Leo [Ghent University, Zwijnaarde (Ghent) (Belgium); Maurice, Vincent; Klein, Lorena; Marcus, Philippe [Institut de Recherche de Chimie Paris, Paris (France); Gonzalez-Garcia, Yaiza; Mol, Arjan [Delft University of Technology, Delft (Netherlands)

    2017-02-15

    When aiming for an increased and more sustainable use of metals a thorough knowledge of the corrosion phenomenon as function of the local metal microstructure is of crucial importance. In this work, we summarize the information presented in our previous publications and present an overview of the different local (electrochemical) techniques that have been proven to be effective in studying the relation between different microstructural variables and their different electrochemical behavior. Atomic force microscopy (AFM), scanning electrochemical microscopy (SECM), and electrochemical scanning tunneling microscopy (EC-STM) were used in combination with electron backscatter diffraction (EBSD). Consequently, correlations could be identified between the grain orientation and grain boundary characteristics, on the one hand, and the electrochemical behavior on the other hand. The grain orientation itself has an influence on the corrosion, and the orientation of the neighboring grains also seems to play a decisive role in the dissolution rate. With respect to intergranular corrosion, only coherent twin boundaries seem to be resistant.

  4. Clusters of interstitial carbon atoms near the graphite surface as a possible origin of dome-like features observed by STM

    OpenAIRE

    Elesin, V. F.; Openov, L. A.

    1999-01-01

    Formation of clusters of interstitial carbon atoms between the surface and second atomic layers of graphite is demonstrated by means of molecular dynamics simulations. It is shown that interstitial clusters result in the dome-like surface features that may be associated with some of the hillocks observed by STM on the irradiated graphite surface.

  5. Oxygen vacancies on TiO2(110) and their interaction with H2O and O2: A combined high-resolution STM and DFT study

    DEFF Research Database (Denmark)

    Wendt, Stefan; Schaub, Renald; Matthiesen, Jesper

    2005-01-01

    From an interplay between high-resolution scanning tunneling microscopy (STM) and density functional theory (DFT) we discuss the origin of various point defects on reduced rutile TiO2(110)–(1 × 1) surfaces. By means of adsorption and desorption experiments using water and oxygen as probe molecule...

  6. Thermomyces lanuginosus STm: a source of thermostable hydrolytic enzymes for novel application in extraction of high-quality natural rubber from Taraxacum kok-saghyz (rubber dandelion)

    Science.gov (United States)

    Hydrolytic enzymes from a newly isolated strain of the thermophilic fungus Thermomyces lanuginosus were used to extract rubber from Taraxacum kok-saghyz commonly known as rubber (or Russian or Kazak(h)) dandelion. The fungus was isolated from garden soil and identified as Thermomyces lanuginosus STm...

  7. Estudio de la modificación de la microestructura de polímeros porosos por metalización mediante STM y AFM

    Directory of Open Access Journals (Sweden)

    Arranz, G.

    2004-04-01

    Full Text Available The results of the characterization of microfiltration membranes by different microscopic techniques: Scanning Electron Microscopy (SEM, Scanning Tunnelling Microscopy (STM and Atomic Force Microscopy (AFM, have been compared. Pore size distribution on the surface and the surface roughness have been determine for each studied membrane. The results show that the effect of the gold layer, needed in SEM and STM, does not affect significatively the pore size distribution for these membranes. However, the effect of this layer decreases the surface roughnes.

    En este trabajo se ha comparado los resultados de caracterización de membranas de microfiltración por diversas técnicas microscópicas: Microscopía Electrónica de Barrido (SEM, Microscopía de Efecto Túnel (STM y Microscopía de Fuerza Atómica (AFM. Se ha determinado la distribución superficial de tamaños de poro y la rugosidad superficial de cada una de las membranas estudiadas. Los resultados muestran que el efecto de la capa de recubrimiento de oro, necesaria en SEM y STM, no afecta significativamente a la distribución de tamaños de poro en este tipo de membranas. Sin embargo el efecto de la capa de recubrimiento disminuye de forma general la rugosidad de la superficie.

  8. Analysis of an ordered, comprehensive STM mutant library in infectious Borrelia burgdorferi: insights into the genes required for mouse infectivity.

    Directory of Open Access Journals (Sweden)

    Tao Lin

    Full Text Available The identification of genes important in the pathogenesis of Lyme disease Borrelia has been hampered by exceedingly low transformation rates in low-passage, infectious organisms. Using the infectious, moderately transformable B. burgdorferi derivative 5A18NP1 and signature-tagged versions of the Himar1 transposon vector pGKT, we have constructed a defined transposon library for the efficient genome-wide investigation of genes required for wild-type pathogenesis, in vitro growth, physiology, morphology, and plasmid replication. To facilitate analysis, the insertion sites of 4,479 transposon mutants were determined by sequencing. The transposon insertions were widely distributed across the entire B. burgdorferi genome, with an average of 2.68 unique insertion sites per kb DNA. The 10 linear plasmids and 9 circular plasmids had insertions in 33 to 100 percent of their predicted genes. In contrast, only 35% of genes in the 910 kb linear chromosome had incapacitating insertions; therefore, the remaining 601 chromosomal genes may represent essential gene candidates. In initial signature-tagged mutagenesis (STM analyses, 434 mutants were examined at multiple tissue sites for infectivity in mice using a semi-quantitative, Luminex-based DNA detection method. Examples of genes found to be important in mouse infectivity included those involved in motility, chemotaxis, the phosphoenolpyruvate phosphotransferase system, and other transporters, as well as putative plasmid maintenance genes. Availability of this ordered STM library and a high-throughput screening method is expected to lead to efficient assessment of the roles of B. burgdorferi genes in the infectious cycle and pathogenesis of Lyme disease.

  9. Whey protein isolate improves acid and bile tolerances of Streptococcus thermophilus ST-M5 and Lactobacillus delbrueckii ssp. bulgaricus LB-12.

    Science.gov (United States)

    Vargas, Luis A; Olson, Douglas W; Aryana, Kayanush J

    2015-04-01

    Acid tolerance and bile tolerance are important probiotic characteristics. Whey proteins contain branched-chain amino acids, which play a role in muscle building and are popular among athletes. Increasing emphasis is being placed on diets containing less carbohydrate, less fat, and more protein. The effect of incremental additions of whey protein isolate (WPI) on probiotic characteristics of pure cultures is not known. The objective of this study was to determine the influence of added WPI on acid tolerance and bile tolerance of pure cultures of Streptococcus thermophilus ST-M5 and Lactobacillus bulgaricus LB-12. The WPI was used at 0 (control), 1, 2 and 3% (wt/vol). Assessment of acid tolerance was conducted on pure cultures at 30-min intervals for 2h of acid exposure and bile tolerance at 1-h intervals for 5h of bile exposure. Use of 1, 2, and 3% WPI improved acid tolerance of Strep. thermophilus ST-M5 and Lb. bulgaricus LB-12. The highest counts for acid tolerance of Strep. thermophilus ST-M5 and Lb. bulgaricus LB-12 were obtained when 3% WPI was used. Use of 2 and 3% WPI improved bile tolerance of Strep. thermophilus ST-M5 and Lb. bulgaricus LB-12 over 5h of bile exposure. The use of WPI is recommended to improve acid and bile tolerance of the yogurt culture bacteria Strep. thermophilus ST-M5 and Lb. bulgaricus LB-12. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  10. The power reinforcement framework revisited

    DEFF Research Database (Denmark)

    Nielsen, Jeppe; Andersen, Kim Normann; Danziger, James N.

    2016-01-01

    Whereas digital technologies are often depicted as being capable of disrupting long-standing power structures and facilitating new governance mechanisms, the power reinforcement framework suggests that information and communications technologies tend to strengthen existing power arrangements within...... public organizations. This article revisits the 30-yearold power reinforcement framework by means of an empirical analysis on the use of mobile technology in a large-scale programme in Danish public sector home care. It explores whether and to what extent administrative management has controlled decision......-making and gained most benefits from mobile technology use, relative to the effects of the technology on the street-level workers who deliver services. Current mobile technology-in-use might be less likely to be power reinforcing because it is far more decentralized and individualized than the mainly expert...

  11. Road-Mapping the Way Forward for Sentinel-3 STM SAR-Mode Waveform Retracking over Water Surfaces

    Science.gov (United States)

    Benveniste, Jérôme; Cotton, David; Dinardo, Salvatore; Lucas, Bruno Manuel; Martin-Puig, Cristina; Ray, Chris; Clarizia, Maria Paola; Gommenginger, Christine

    2013-04-01

    . However, since the ultimate goal of the SAMOSA project is to deliver to the Sentinel-3 Surface Topography Mission Product and Algorithm Development (S-3 STM PAD) a Detailed Processing Model of a SAR ocean waveform re-tracker based on the best SAMOSA model to operationally re-track Sentinel-3 STM SAR-Mode L1b waveforms, the need for the full mathematical complexity of the SAMOSA2 model was re-evaluated. With this in mind, the SAMOSA team assessed a number of simplifications that can transform the SAMOSA2 model into a lighter, computationally more efficient, purely analytical formulation for input into the SAR re-tracker scheme for the Sentinel-3 STM PAD. The simplifications that have been considered involve the omission in the model of second order effects such as non-linear terms in the model, ocean surface skewness, and electromagnetic bias. Their impact has been evaluated. This SAMOSA3 model has the advantage to be a pure analytical solution, expressed by means of modified Bessel functions of first and second kind and returns no singularities for the full range of the gate bins. An extensive validation was performed. First equivalence between SAMOSA3, SAMOSA2 & SAMOSA1 models was confirmed and then a a sensitivity study on the input parameters and the re-tracking approach was carried out. Finally, the SAMOSA3 Model and re-tracker was applied to Cryosat-2 L1B SAR waveforms and the performance was studied as well as the sensitivity to mispointing. Two areas were chosen as representative of the high and low ocean dynamics regions, respectively the South Norwegian Sea and the Caspian Sea. Finally the SAMOSA3 output was validated against in situ wave buoy measurements. An overview of these results will be shown here.

  12. Observation of Quantum-Size Effects at Room Temperature on Metal Surfaces With STM.

    Science.gov (United States)

    Avouris, P; Lyo, I W

    1994-05-13

    Surface steps act as confining barriers for electrons in metal-surface states. Thus, narrow terraces and small single-atom-high metal islands act as low-dimensional, electron-confining structures. In sufficiently small structures, quantum-size effects are observable even at room temperature. Scanning tunneling spectroscopy is used to image the probability amplitude distributions and discrete spectra of the confined states. Examination of the electronic structure of the steps provides evidence for electron-density smoothing and the formation of step-edge states. Estimates of the electron-confining barriers are obtained.

  13. Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

    KAUST Repository

    Sun, Tiancheng

    2017-12-25

    Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

  14. Revisiting tourist behavior via destination brand worldness

    Directory of Open Access Journals (Sweden)

    Murat Kayak

    2016-11-01

    Full Text Available Taking tourists’ perspective rather than destination offerings as its core concept, this study introduces “perceived destination brand worldness” as a variable. Perceived destination brand worldness is defined as the positive perception that a tourist has of a country that is visited by tourists from all over the world. Then, the relationship between perceived destination brand worldness and intention to revisit is analyzed using partial least squares regression. This empirical study selects Taiwanese tourists as its sample, and the results show that perceived destination brand worldness is a direct predictor of intention to revisit. In light of these empirical findings and observations, practical and theoretical implications are discussed.

  15. Issues of Page Representation and Organisation in Web Browser's Revisitation Tools

    Directory of Open Access Journals (Sweden)

    Andy Cockburn

    2000-05-01

    Full Text Available Many commercial and research WWW browsers include a variety of graphical revisitation tools that let users return to previously seen pages. Examples include history lists, bookmarks and site maps. In this paper, we examine two fundamental design and usability issues that all graphical tools for revisitation must address. First, how can individual pages be represented to best support page identification? We discuss the problems and prospects of various page representations: the pages themselves, image thumbnails, text labels, and abstract page properties. Second, what display organisation schemes can be used to enhance the visualisation of large sets of previously visited pages? We compare temporal organisations, hub-and spoke dynamic trees, spatial layouts and site maps.

  16. STM Studies of TbTe3: Evidence for a Fully Incommensurate Charge Density Wave

    Energy Technology Data Exchange (ETDEWEB)

    Fang, A.; Ru, N.; Fisher, I.R.; /Stanford U., Appl. Phys. Dept.; Kapitulnik, A.; /Stanford U., Appl. Phys. Dept. /Stanford U., Phys. Dept.

    2010-02-15

    We observe unidirectional charge density wave ordering on the cleaved surface of TbTe{sub 3} with a Scanning Tunneling Microscope at {approx}6 K. The modulation wave-vector q{sub CDW} as determined by Fourier analysis is 0.71 {+-} 0.02 x2{pi}/c. Where c is one edge of the in-plane 3D unit cell. Images at different tip-sample voltages show the unit cell doubling effects of dimerization and the layer below. Our results agree with bulk X-ray measurements, with the addition of (1/3) x2{pi}/a ordering perpendicular to the CDW. Our analysis indicates that the CDW is incommensurate.

  17. STM Studies of Spin-­Orbit Coupled Phases in Real-­ and Momentum-­Space

    Energy Technology Data Exchange (ETDEWEB)

    Madhavan, Vidya [Univ. of Illinois, Urbana, IL (United States)

    2016-10-17

    The recently discovered class of spin-orbit coupled materials with interesting topological character are fascinating both from fundamental as well as application point of view. Two striking examples are 3D topological insulators (TIs) and topological crystalline insulators (TCIs). These materials host linearly dispersing (Dirac like) surface states with an odd number of Dirac nodes and are predicted to carry a quantized half-integer value of the axion field. The non-trivial topological properties of TIs and TCIs arise from strong spin-orbit coupling leading to an inverted band structure; which also leads to the chiral spin texture in momentum space. In this project we used low temperature scanning tunneling microscopy (STM) and spectroscopy (STS) to study materials with topological phases in real- and momentum-space. We studied both single crystals and thin films of topological materials which are susceptible to being tuned by doping, strain or gating, allowing us to explore their physical properties in the most interesting regimes and set the stage for future technological applications. .

  18. In situ coherent x-ray scattering and STM studies of hexagonally reconstructed Au(001) in Electrolytes

    Science.gov (United States)

    Pierce, Michael S.; Komanicky, Vladimir; Barbour, Andi; Hennessy, Daniel; Su, Jun-Dar; Sandy, Alec; You, Hoydoo

    2011-03-01

    We have studied the dynamics of Au(001) and Au(111) surfaces in situ in 0.1 M HClO4 electrolyte solution using coherent x-ray scattering experiments and STM microscopy. Our coherent x-ray scattering experiments measure a correlation time for the surface as a function of applied potentials. Coherent x-ray scattering differs from the ordinary x-ray diffraction in sensitivity to the structural and temporal details. The correlation times were obtained from measurements conducted while the surface is in equilibrium and the ordinary surface scattering intensity is constant. The correlation time changes from high 103 seconds to low 102 seconds. The correlation times of reconstructed surfaces at low potential are at least an order of magnitude smaller than those measured at the reconstructed surfaces in vacuum. The correlation times also change dramatically in response to the applied potential. These experiments also represent the first successful application of coherent x-ray scattering to the study of electrochemical interfaces in situ. Work at ANL is supported by DOE-BES and work at SU by VEGA.

  19. An Investigation into the Modality Specificity of L2 Learners' STM Abilities in Learning Vocabulary via PDAs

    Directory of Open Access Journals (Sweden)

    Saeed Khazaie

    2012-09-01

    Full Text Available Parallel with the rapid growth of wireless technology and potentials of mobile learning for language teaching/learning, employing mobile devices in language learning seems indispensable. To this end, designing learning materials suitable for different types of mobile devices regarding dual coding (DCT and cognitive load (CLT theories seems inevitable. In this study, multimedia were employed for designing two types of learning materials. Since short-term memory plays an important role in language learning, learners’ visual and verbal short-term memories were taken into consideration, too. 161 L2 Learners aged 19 and 23 years old participated in the major phases of an experiment via personal digital assistant (PDA. Based on their scores on the English vocabulary recognition and recall (EVRR tests and the statistical analysis of the results, it was revealed that delivery of learning materials with pictorial and written annotations combined rather than delivery of learning materials without such annotations to learners with high-visual and high-verbal abilities, learners with high-visual but low-verbal ability, and learners with low-visual but high-verbal ability results in better vocabulary learning outcomes. However, this was not the case for learners with low-visual and low-verbal abilities. This study acknowledges the relation between STM and the relevant modalities of materials presentation.

  20. STM/STS study of superconducting properties in Ca10(Pt4As8)(Fe2As2)5

    Science.gov (United States)

    Kim, Jisun; Nam, Hyoungdo; Li, Guorong; Karki, Amar; Shih, Chih-Kang; Zhang, Jiandi; Jin, Rongying; Plummer, E. W.

    2014-03-01

    Newly discovered iron-based superconductor, Ca10(Pt4As8)(Fe2As2)5 (Tc = 34 K) is studied using scanning tunneling microscopy/spectroscopy (STM/S). Given the symmetry of the crystal structure, several surface terminations are expected with roughly same probability: 1) Ca or partial Ca layer on top Fe2As2; 2) Ca or partial Ca layer on top Pt4As8 layer; 3) A Fe2As2 layer, and; 4) A Pt4As8layer.Surprisingly,Fe2As2 related layers (1 & 3) are rarely observed (less than 1%). Instead, we observe Pt4As8 layers separated by unit-cell-high (~ 1 nm) steps accompanied with Ca or partial Ca layer on top Pt4As8 layer (1 - 2 Å step height). Scanning tunneling spectroscopy reveals different spectra for each surface, with superconducting coherence peaks seen only on Ca layers. We argue that intermediary layers are proximity-coupled to superconducting Fe2As2 layers. The results from Ca10(Pt4As8)(Fe2As2)5 are discussed with the properties observed in other iron-based superconductors. Funded by NSF

  1. A combined STM and SPA-LEED study of the "explosive" nucleation and collective diffusion in Pb/Si(111)

    Science.gov (United States)

    Hattab, H.; Hupalo, M.; Hershberger, M. T.; Horn von Hoegen, M.; Tringides, M. C.

    2016-04-01

    A novel type of very fast nucleation was recently found in Pb/Si(111) with 4- to 7-layer high islands becoming crystalline in an "explosive" way, when the Pb deposited amount in the wetting layer is compressed to θc 1.22 ML, well above the metallic Pb(111) density. This "explosive" nucleation is very different from classical nucleation when island growth is more gradual and islands grow in size by single adatom aggregation [8]. In order to identify the key parameters that control the nucleation we used scanning tunneling microscopy (STM) and spot profile analysis low energy electron diffraction (SPA-LEED). It was found that the number and duration of steps in iterative deposition used to approach θc and the flux rate have dramatic effects on the crystallization process. Larger depositions over shorter times induce greater spatial coverage fluctuations, so local areas can reach the critical coverage θc easier. This can trigger the collective motion of the wetting layer from far away to build the Pb islands "explosively". The SPA-LEED experiments show that even low flux experiments in iterative deposition experiments can trigger transfer of material to the superstable 7-layer islands, as seen from the stronger satellite rings close to the (00) spot.

  2. Design and Implement of Pyroelectric Energy Harvester Experimental Measurement System Based on STM32F103VET6

    Directory of Open Access Journals (Sweden)

    Honghua Liao

    2016-01-01

    Full Text Available A design scheme of the pyroelectric energy harvesting and conversion experimental measurement system was proposed. It can be used to evaluate the harvesting and conversion properties of pyroelectric energy harvester. The STM32F103VET6 microcontroller is used as control core, and the variation temperature filed can be generated by using semiconductor chilling plate, which is controlled by Fuzzy-PID temperature module, to achieve the temperature rapid heating or cooling. In system, using DS18B20 to achieve the temperature real-time data acquisition, using TF TLCD 2.8 LCD to set the initial parameters and display the related real-time parameters. The measurement principle, system hardware and software architecture of experiment measurement system are specially described in article. Simultaneously, the energy conversion and harvesting properties of novel pyroelectric energy harvester, which is prepared by Pb[(MnxNb1-x1/2(MnxSb1-x1/2]y(ZrzTi1-z1-yO3 (PMnN-PMS-PZT ceramics, is discussed. The experiment results show that it can quickly realize the system temperature heating or cooling, and also can satisfy the experiment needs of the properties of pyroelectric energy harvesting and conversion characteristics measurement.

  3. Thirty per cent contrast in secondary-electron imaging by scanning field-emission microscopy.

    Science.gov (United States)

    Zanin, D A; De Pietro, L G; Peter, Q; Kostanyan, A; Cabrera, H; Vindigni, A; Bähler, Th; Pescia, D; Ramsperger, U

    2016-11-01

    We perform scanning tunnelling microscopy (STM) in a regime where primary electrons are field-emitted from the tip and excite secondary electrons out of the target-the scanning field-emission microscopy regime (SFM). In the SFM mode, a secondary-electron contrast as high as 30% is observed when imaging a monoatomic step between a clean W(110)- and an Fe-covered W(110)-terrace. This is a figure of contrast comparable to STM. The apparent width of the monoatomic step attains the 1 nm mark, i.e. it is only marginally worse than the corresponding width observed in STM. The origin of the unexpected strong contrast in SFM is the material dependence of the secondary-electron yield and not the dependence of the transported current on the tip-target distance, typical of STM: accordingly, we expect that a technology combining STM and SFM will highlight complementary aspects of a surface while simultaneously making electrons, selected with nanometre spatial precision, available to a macroscopic environment for further processing.

  4. Personality-relationship transactions revisited.

    Science.gov (United States)

    Neyer, Franz J; Mund, Marcus; Zimmermann, Julia; Wrzus, Cornelia

    2014-12-01

    The transactional paradigm states that people create, maintain, and change their environments according to their personalities. At the same time, the environment reacts back on personality. As social relationships are part of an individual's environment, this likewise implies that there are reciprocal transactions between personality and relationships. However, earlier studies have concluded that adult personality traits are so stable that they have a stronger effect on later relationships, but that relationship effects on personality are negligible. In this article, we contend that personality-relationship transactions should be revisited. We submit that the relative powers of personality versus relationship effects depend on the type of life transition during which the effects take place: Relationship effects on personality development are more likely to emerge in the context of rather normative and highly scripted life transitions, whereas personality effects on relationship development are more likely to occur in the context of rather non-normative life transitions that are less regulated by social expectations. We illustrate these assumptions with examples from our own work and other findings reported in the literature. Furthermore, we theorize that effects of personality-relationship transactions on health also vary with the normativeness of the eliciting life transition. © 2013 Wiley Periodicals, Inc.

  5. Individualist Biocentrism vs. Holism Revisited

    Directory of Open Access Journals (Sweden)

    Katie McShane

    2014-06-01

    Full Text Available While holist views such as ecocentrism have considerable intuitive appeal, arguing for the moral considerability of ecological wholes such as ecosystems has turned out to be a very difficult task. In the environmental ethics literature, individualist biocentrists have persuasively argued that individual organisms—but not ecological wholes—are properly regarded as having a good of their own . In this paper, I revisit those arguments and contend that they are fatally flawed. The paper proceeds in five parts. First, I consider some problems brought about by climate change for environmental conservation strategies and argue that these problems give us good pragmatic reasons to want a better account of the welfare of ecological wholes. Second, I describe the theoretical assumptions from normative ethics that form the background of the arguments against holism. Third, I review the arguments given by individualist biocentrists in favour of individualism over holism. Fourth, I review recent work in the philosophy of biology on the units of selection problem, work in medicine on the human biome, and work in evolutionary biology on epigenetics and endogenous viral elements. I show how these developments undermine both the individualist arguments described above as well as the distinction between individuals and wholes as it has been understood by individualists. Finally, I consider five possible theoretical responses to these problems.

  6. The mycorrhiza helper bacteria revisited.

    Science.gov (United States)

    Frey-Klett, P; Garbaye, J; Tarkka, M

    2007-01-01

    In natural conditions, mycorrhizal fungi are surrounded by complex microbial communities, which modulate the mycorrhizal symbiosis. Here, the focus is on the so-called mycorrhiza helper bacteria (MHB). This concept is revisited, and the distinction is made between the helper bacteria, which assist mycorrhiza formation, and those that interact positively with the functioning of the symbiosis. After considering some examples of MHB from the literature, the ecological and evolutionary implications of the relationships of MHB with mycorrhizal fungi are discussed. The question of the specificity of the MHB effect is addressed, and an assessment is made of progress in understanding the mechanisms of the MHB effect, which has been made possible through the development of genomics. Finally, clear evidence is presented suggesting that some MHB promote the functioning of the mycorrhizal symbiosis. This is illustrated for three critical functions of practical significance: nutrient mobilization from soil minerals, fixation of atmospheric nitrogen, and protection of plants against root pathogens. The review concludes with discussion of future research priorities regarding the potentially very fruitful concept of MHB.

  7. A high-stability scanning tunneling microscope achieved by an isolated tiny scanner with low voltage imaging capability

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qi; Wang, Junting; Lu, Qingyou, E-mail: qxl@ustc.edu.cn [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China); Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hou, Yubin [High Magnetic Field Laboratory, Chinese Academy of Sciences and University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2013-11-15

    We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d{sub 31} coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.

  8. A high-stability scanning tunneling microscope achieved by an isolated tiny scanner with low voltage imaging capability

    Science.gov (United States)

    Wang, Qi; Hou, Yubin; Wang, Junting; Lu, Qingyou

    2013-11-01

    We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d31 coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.

  9. New sub-family of lysozyme-like proteins shows no catalytic activity: crystallographic and biochemical study of STM3605 protein from Salmonella Typhimurium

    Energy Technology Data Exchange (ETDEWEB)

    Michalska, Karolina; Brown, Roslyn N.; Li, Hui; Jedrzejczak, Robert; Niemann, George; Heffron, Fred; Cort, John R.; Adkins, Joshua N.; Babnigg, Gyorgy; Joachimiak, Andrzej

    2013-03-01

    Phage viruses that infect prokaryotes integrate their genome into the host chromosome; thus, microbial genomes typically contain genetic remnants of both recent and ancient phage infections. Often phage genes occur in clusters of atypical G+C content that reflect integration of the foreign DNA. However, some phage genes occur in isolation without other phage gene neighbors, probably resulting from horizontal gene transfer. In these cases, the phage gene product is unlikely to function as a component of a mature phage particle, and instead may have been co-opted by the host for its own benefit. The product of one such gene from Salmonella enterica serovar Typhimurium, STM3605, encodes a protein with modest sequence similarity to phage-like lysozyme (N-acetylmuramidase) but appears to lack essential catalytic residues that are strictly conserved in all lysozymes. Close homologs in other bacteria share this characteristic. The structure of the STM3605 protein was characterized by X-ray crystallography, and functional assays showed that it is a stable, folded protein whose structure closely resembles lysozyme. However, this protein is unlikely to hydrolyze peptidoglycan. Instead, STM3605 is presumed to have evolved an alternative function because it shows some lytic activity and partitions to micelles.

  10. Molecular images and vibrational spectroscopy of sorbic acid with the scanning tunneling microscope

    Science.gov (United States)

    Smith, Douglas P. E.; Kirk, Michael D.; Quate, Calvin F.

    1987-06-01

    Images of sorbic acid molecules absorbed onto graphite have been taken with a scanning tunneling microscope (STM) operating in liquid helium. Molecular clusters were clearly observed, as was the atomic structure of the graphite substrate. The molecules were seen to diffuse across the substrate at a rate of about 1 Å/min. When dI/dV vs V was measured with the STM probe directly over a sorbic acid molecule, a well-defined spectrum of peaks was obtained whose energies corresponded to the vibrational resonances of the molecule. Large changes in the spectra occurred if the tip was moved a lateral distance of 5 Å.

  11. Unusual island formations of Ir on Ge (111) studied by STM

    Science.gov (United States)

    van Zijll, M.; Huffman, E.; Lovinger, D. J.; Chiang, S.

    2017-12-01

    Island formation on the Ir/Ge(111) surface is studied using ultrahigh vacuum scanning tunneling microscopy. Ir was deposited at room temperature onto a Ge (111) substrate with coverages between 0.5 and 2.0 monolayers (ML). The samples were annealed to temperatures between 550 and 800 K, and then cooled prior to imaging. With 1.0 ML Ir coverage, at annealing temperatures 650-750 K, round islands form at locations where domain boundaries of the substrate reconstruction intersect. Both the substrate and the islands display a (√{ 3} x√{ 3}) R30∘ reconstruction. Additionally, a novel surface formation is observed where the Ir gathers along the antiphase domain boundaries between competing surface domains of the Ge surface reconstruction. This gives the appearance of the Ir in the domain boundaries forming pathways between different islands. The islands formed at higher annealing temperatures resulted in larger island sizes, which is evidence of Ostwald ripening. We present a model for the islands and the pathways which is consistent with our observations.

  12. The Future of Engineering Education--Revisited

    Science.gov (United States)

    Wankat, Phillip C.; Bullard, Lisa G.

    2016-01-01

    This paper revisits the landmark CEE series, "The Future of Engineering Education," published in 2000 (available free in the CEE archives on the internet) to examine the predictions made in the original paper as well as the tools and approaches documented. Most of the advice offered in the original series remains current. Despite new…

  13. Revisiting separation properties of convex fuzzy sets

    Science.gov (United States)

    Separation of convex sets by hyperplanes has been extensively studied on crisp sets. In a seminal paper separability and convexity are investigated, however there is a flaw on the definition of degree of separation. We revisited separation on convex fuzzy sets that have level-wise (crisp) disjointne...

  14. The Evil of Banality: Arendt Revisited

    Science.gov (United States)

    Minnich, Elizabeth

    2014-01-01

    "The banality of evil" (Arendt) remains controversial and useful. Ironically, the concept is now itself a banality. To revisit and extend it, we consider the "evil of banality", the profound dangers of cliched thoughtlessness. A distinction is proposed: "intensive" versus "extensive evils". The former takes…

  15. Natural Language Processing concepts and methods revisited

    OpenAIRE

    IJSMI,EDITOR

    2017-01-01

    The paper starts with the history of Natural Language Processing (NLP) and revisits the concepts and methods involved in the NLP. It provides overview of different classifiers and language modelling techniques. The paper also lists the different fields where NLP is used and also the software available to carry out NLP.

  16. The methodology of corpus cavernosum electromyography revisited

    NARCIS (Netherlands)

    Jiang, X. G.; Wijkstra, H.; Meuleman, E. J. H.; Wagner, G.

    2004-01-01

    Objective: The methodology of corpus cavernosum electromyography (CC-EMG) was revisited, in order to overcome current methodological difficulties that hinder its clinical application. Materials and methods: Using an 8-channel device, CC-EMG was performed in 12 healthy volunteers. Surface electrodes

  17. Covalently Immobilised Cytochrome C Imaged by In Situ Scanning Tunnelling Microscopy

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Olesen, Klaus G.; Danilov, Alexey I.

    1997-01-01

    In situ scanning tunnelling microscopy (STM) imaging of cytochrome c (cyt c) on polycrystalline Pt surfaces and on Au(lll) was achieved first by covalent immobilisation of 3-aminopropyltriethoxysilane (3-APTS) brought to react with oxide present on the Pt surfaces. Covalently bound 3-APTS forms a...

  18. Ambulatory thyroidectomy: a multistate study of revisits and complications.

    Science.gov (United States)

    Orosco, Ryan K; Lin, Harrison W; Bhattacharyya, Neil

    2015-06-01

    Determine rates and reasons for revisits after ambulatory adult thyroidectomy. Cross-sectional analysis of multistate ambulatory surgery and hospital databases. Ambulatory surgery data from the State Ambulatory Surgery Databases of California, Florida, Iowa, and New York for calendar years 2010 and 2011. Ambulatory thyroidectomy cases were linked to state ambulatory, emergency, and inpatient databases for revisit encounters occurring within 30 days. The numbers of revisits, mortality, and associated diagnoses were analyzed. A total of 25,634 cases of ambulatory thyroid surgery were identified: 44.2% total thyroidectomy (TT) and 55.8% partial thyroidectomy (PT). Common indications for surgery included goiter/cyst (39.5%), benign/uncertain neoplasm (24.2%), and malignant neoplasm (24.0%). The 30-day revisit rate was 7.2% (n = 1858; 61.8% emergency department, 22.4% inpatient admission, and 15.8% ambulatory surgery center). The most common diagnosis at revisit was hypocalcemia (20.8% of revisits), followed by wound hematoma/seroma/bleeding (7.1%). Higher rates of revisit, hypocalcemia, and hematoma/seroma/bleeding were seen in patients undergoing TT (P ambulatory thyroidectomy demonstrates a good postoperative morbidity and mortality profile. Common reasons for revisits included hypocalcemia and bleeding/seroma/hematoma, which occurred with relatively high frequencies as late as a week after surgery. Quality improvement measures should be targeted at lowering revisit rates and safely managing complications. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  19. The Global Precipitation Measurement (GPM) Microwave Imager (GMI) Instrument: Role, Performance, and Status

    National Research Council Canada - National Science Library

    Bidwell, S. W; Flaming, G. M; Durning, J. F; Smith, E. A

    2005-01-01

    The Global Precipitation Measurement (GPM) Microwave Imager (GMI) instrument is a multi-channel, conical-scanning, microwave radiometer serving an essential role in the near-global-coverage and frequent-revisit-time requirements of GPM...

  20. Revisiting the 1761 Transatlantic Tsunami

    Science.gov (United States)

    Baptista, Maria Ana; Wronna, Martin; Miranda, Jorge Miguel

    2016-04-01

    The tsunami catalogs of the Atlantic include two transatlantic tsunamis in the 18th century the well known 1st November 1755 and the 31st March 1761. The 31st March 1761 earthquake struck Portugal, Spain, and Morocco. The earthquake occurred around noontime in Lisbon alarming the inhabitants and throwing down ruins of the past 1st November 1755 earthquake. According to several sources, the earthquake was followed by a tsunami observed as far as Cornwall (United Kingdom), Cork (Ireland) and Barbados (Caribbean). The analysis of macroseismic information and its compatibility with tsunami travel time information led to a source area close to the Ampere Seamount with an estimated epicenter circa 34.5°N 13°W. The estimated magnitude of the earthquake was 8.5. In this study, we revisit the tsunami observations, and we include a report from Cadiz not used before. We use the results of the compilation of the multi-beam bathymetric data, that covers the area between 34°N - 38°N and 12.5°W - 5.5°W and use the recent tectonic map published for the Southwest Iberian Margin to select among possible source scenarios. Finally, we use a non-linear shallow water model that includes the discretization and explicit leap-frog finite difference scheme to solve the shallow water equations in the spherical or Cartesian coordinate to compute tsunami waveforms and tsunami inundation and check the results against the historical descriptions to infer the source of the event. This study received funding from project ASTARTE- Assessment Strategy and Risk Reduction for Tsunamis in Europe a collaborative project Grant 603839, FP7-ENV2013 6.4-3

  1. The Generalized Image

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    2017-01-01

    the abstract and figurative has ever been qualified, an unlimited number of images after 1900 – whether painted, printed or screen-based – have significantly obscured any clear distinction between the two. Hence, if one wishes to understand the very nature of modern images it is indispensable to ask what...... the issue by revisiting a series of iconic images in early 1920s avant-garde film by the artists Man Ray and Fernand Léger. On this background, and in dialogue with film theorists and philosophers such as Malcolm Le Grice and Gilles Deleuze, I outline the basic properties and aesthetic potentials of what I...

  2. Images.

    Science.gov (United States)

    Barr, Catherine, Ed.

    1997-01-01

    The theme of this month's issue is "Images"--from early paintings and statuary to computer-generated design. Resources on the theme include Web sites, CD-ROMs and software, videos, books, and others. A page of reproducible activities is also provided. Features include photojournalism, inspirational Web sites, art history, pop art, and myths. (AEF)

  3. Revisiting Cementoblastoma with a Rare Case Presentation

    Directory of Open Access Journals (Sweden)

    Vijayanirmala Subramani

    2017-01-01

    Full Text Available Cementoblastoma is a rare benign odontogenic neoplasm which is characterized by the proliferation of cellular cementum. Diagnosis of cementoblastoma is challenging because of its protracted clinical, radiographic features, and bland histological appearance; most often cementoblastoma is often confused with other cementum and bone originated lesions. The aim of this article is to overview/revisit, approach the diagnosis of cementoblastoma, and also present a unique radiographic appearance of a cementoblastoma lesion associated with an impacted tooth.

  4. The Faraday effect revisited: General theory

    OpenAIRE

    Cornean, Horia Decebal; Nenciu, Gheorghe; Pedersen, Thomas Garm

    2005-01-01

    This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. For free electrons, the transverse conductivity can be explicitly computed and coincides with the classical result. In the general case, using magnetic perturbation theory, the conductivity tensor is expanded in powers of the strength of th...

  5. A safe vaccine (DV-STM-07) against Salmonella infection prevents abortion and confers protective immunity to the pregnant and new born mice.

    Science.gov (United States)

    Negi, Vidya Devi; Nagarajan, Arvindhan G; Chakravortty, Dipshikha

    2010-02-10

    Pregnancy is a transient immuno-compromised condition which has evolved to avoid the immune rejection of the fetus by the maternal immune system. The altered immune response of the pregnant female leads to increased susceptibility to invading pathogens, resulting in abortion and congenital defects of the fetus and a subnormal response to vaccination. Active vaccination during pregnancy may lead to abortion induced by heightened cell mediated immune response. In this study, we have administered the highly attenuated vaccine strain DeltapmrG-HM-D (DV-STM-07) in female mice before the onset of pregnancy and followed the immune reaction against challenge with virulent S. Typhimurium in pregnant mice. Here we demonstrate that DV-STM-07 vaccine gives protection against Salmonella in pregnant mice and also prevents Salmonella induced abortion. This protection is conferred by directing the immune response towards Th2 activation and Th1 suppression. The low Th1 response prevents abortion. The use of live attenuated vaccine just before pregnancy carries the risk of transmission to the fetus. We have shown that this vaccine is safe as the vaccine strain is quickly eliminated from the mother and is not transmitted to the fetus. This vaccine also confers immunity to the new born mice of vaccinated mothers. Since there is no evidence of the vaccine candidate reaching the new born mice, we hypothesize that it may be due to trans-colostral transfer of protective anti-Salmonella antibodies. These results suggest that our vaccine DV-STM-07 can be very useful in preventing abortion in the pregnant individuals and confer immunity to the new born. Since there are no such vaccine candidates which can be given to the new born and to the pregnant women, this vaccine holds a very bright future to combat Salmonella induced pregnancy loss.

  6. A safe vaccine (DV-STM-07 against Salmonella infection prevents abortion and confers protective immunity to the pregnant and new born mice.

    Directory of Open Access Journals (Sweden)

    Vidya Devi Negi

    Full Text Available Pregnancy is a transient immuno-compromised condition which has evolved to avoid the immune rejection of the fetus by the maternal immune system. The altered immune response of the pregnant female leads to increased susceptibility to invading pathogens, resulting in abortion and congenital defects of the fetus and a subnormal response to vaccination. Active vaccination during pregnancy may lead to abortion induced by heightened cell mediated immune response. In this study, we have administered the highly attenuated vaccine strain DeltapmrG-HM-D (DV-STM-07 in female mice before the onset of pregnancy and followed the immune reaction against challenge with virulent S. Typhimurium in pregnant mice. Here we demonstrate that DV-STM-07 vaccine gives protection against Salmonella in pregnant mice and also prevents Salmonella induced abortion. This protection is conferred by directing the immune response towards Th2 activation and Th1 suppression. The low Th1 response prevents abortion. The use of live attenuated vaccine just before pregnancy carries the risk of transmission to the fetus. We have shown that this vaccine is safe as the vaccine strain is quickly eliminated from the mother and is not transmitted to the fetus. This vaccine also confers immunity to the new born mice of vaccinated mothers. Since there is no evidence of the vaccine candidate reaching the new born mice, we hypothesize that it may be due to trans-colostral transfer of protective anti-Salmonella antibodies. These results suggest that our vaccine DV-STM-07 can be very useful in preventing abortion in the pregnant individuals and confer immunity to the new born. Since there are no such vaccine candidates which can be given to the new born and to the pregnant women, this vaccine holds a very bright future to combat Salmonella induced pregnancy loss.

  7. In situ video-STM studies of methyl thiolate surface dynamics and self-assembly on Cu(100) electrodes.

    Science.gov (United States)

    Yang, Yaw-Chia; Taranovskyy, Andriy; Magnussen, Olaf M

    2012-10-09

    The atomic-scale surface dynamic behavior of adsorbed methyl thiolate on Cu(100) electrodes, prepared via the dissociative adsorption of dimethyl disulfide, was studied in 0.01 M HCl solution over a wide regime of coverages. Using video-rate in situ STM, we directly observed the motion of the adsorbates within the c(2 × 2) lattice of the chloride coadsorbates with high spatial and temporal resolution, revealing complex mutual interactions of the organic adsorbates as well as pronounced interactions with Cu adatoms, which significantly affect the thiolate self-assembly. Quantitative measurements of the tracer diffusion of isolated thiolates reveal a 35 meV lower diffusion barrier as compared to that of sulfide adsorbates with a linear potential dependence of 0.5 eV/V. The effective intermolecular interactions between the thiolates resemble those between adsorbed sulfide and are repulsive at the nearest-neighbor distance of a(0) within the c(2 × 2) lattice, attractive at the next-nearest-neighbor distance of √2a(0) and again repulsive at a distance of 2a(0). Thiolates at these small spacings are found to exhibit characteristic collective properties, which are significant for the self-assembly of these species: First, their mobility is greatly enhanced relative to that of isolated thiolates. Second, Cu adatoms can be transiently trapped in between the two thiolates of a metastable dimer with an intermolecular spacing of √2a(0). With increasing coverage, small, highly mobile molecular clusters and subsequently the formation of ordered adlayer domains with a c(2 × 6) structure are observed. Common structural elements of the clusters and c(2 × 6) domains are stripes of thiolate dimers, which are oriented in the [011] direction, spaced at distances of √2a(0) and of which a large fraction is occupied by Cu adatoms. The c(2 × 6) phase can be rationalized as a close-packed arrangement of these dimer stripes. Because of the self-acceleration of the thiolate

  8. Cannabidiol-2',6'-dimethyl ether stimulates body weight gain in apolipoprotein E-deficient BALB/c. KOR/Stm Slc-Apoe(shl) mice.

    Science.gov (United States)

    Takeda, Shuso; Hirota, Rena; Teradaira, Sari; Takeda-Imoto, Masumi; Watanabe, Kazuhito; Toda, Akihisa; Aramaki, Hironori

    2015-12-01

    The biological activities of cannabidiol (CBD), a major non-psychotropic constituent of the fiber-type cannabis plant, have been examined in detail (e.g., CBD modulation of body weight in mice and rats). However, few studies have investigated the biological activities of cannabidiol-2',6'-dimethyl ether (CBDD), a dimethyl ether derivative of the parent CBD. We herein focused on the effects of CBDD on body weight changes in mice, and demonstrated that it stimulated body weight gain in apolipoprotein E (ApoE)-deficient BALB/c. KOR/Stm Slc-Apoe(shl) mice, especially between 10 and 20 weeks of age.

  9. Recent STM, DFT and HAADF-STEM studies of sulfide-based hydrotreating catalysts: Insight into mechanistic, structural and particle size effects

    DEFF Research Database (Denmark)

    Besenbacher, Flemming; Brorson, M.; Clausen, B.S.

    2008-01-01

    -angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) studies which have provided insight into the detailed atomic structure. In accordance with earlier theoretical studies, the experimental studies show that the Ni-Mo-S structures may in some instances differ from the Co...... and support effects which play an important role in practical HDS. Recent STM studies have shown that MoS2 clusters below 2-3 nm may exhibit new structural and electronic properties, and a large variety of size-dependent structures have been identified. In view of the large structure sensitivity...

  10. Estágios iniciais da eletrodeposição de cobalto e níquel acompanhados por EC-STM e EC-AGFM

    OpenAIRE

    Carmem Rosane Isse Gomes

    2003-01-01

    Neste trabalho foram eletrodepositados filmes ultrafinos de cobalto e níquel sobre substrato de Au/mica. Os estágios iniciais da deposição foram acompanhados in-situ pelo uso das técnicas de EC-STM (microscopia de varredura por tunelamento – modo eletroquímico) e EC-AGFM (magnetome tria de força de gradiente de campo alternado – modo eletroquímico), que se constitui em uma nova técnica para avaliação de propriedades magnéticas de filmes ultrafinos eletrodepositados. Como resultado, foi obtido...

  11. A combined UHV-STM-flow cell set-up for electrochemical/electrocatalytic studies of structurally well-defined UHV prepared model electrodes

    DEFF Research Database (Denmark)

    Schnaidt, J.; Beckord, S.; Engstfeld, Albert Kilian

    2017-01-01

    We describe the construction and discuss the performance of a novel combined ultrahigh vacuum (UHV)-electrochemistry set-up, allowing the controlled preparation and structural characterization of complex nanostructured electrode surfaces by high resolution scanning tunnelling microscopy (STM) under...... collector electrode or by differential electrochemical mass spectrometry (DEMS). The potential of the set-up will be illustrated in two electrocatalytic reactions on complex, but structurally well-defined bimetallic electrode surfaces, O-2 reduction on PtxAg1-x/Pt(111) monolayer surface alloys and bulk CO...

  12. Apparent Barrier Height in Scanning Tunneling Microscopy Revisited

    DEFF Research Database (Denmark)

    Olesen, L.; Brandbyge, Mads; Sørensen, Mads Reinholdt

    1996-01-01

    The apparent barrier height phi(ap), that is, the rate of change of the logarithm of the conductance with tip-sample separation in a scanning tunneling microscope (STM), has been measured for Ni, Pt, and Au single crystal surfaces. The results show that phi(ap) is constant until point contact is ...

  13. Measuring hospital quality using pediatric readmission and revisit rates.

    Science.gov (United States)

    Bardach, Naomi S; Vittinghoff, Eric; Asteria-Peñaloza, Renée; Edwards, Jeffrey D; Yazdany, Jinoos; Lee, Henry C; Boscardin, W John; Cabana, Michael D; Dudley, R Adams

    2013-09-01

    To assess variation among hospitals on pediatric readmission and revisit rates and to determine the number of high- and low-performing hospitals. In a retrospective analysis using the State Inpatient and Emergency Department Databases from the Healthcare Cost and Utilization Project with revisit linkages available, we identified pediatric (ages 1-20 years) visits with 1 of 7 common inpatient pediatric conditions (asthma, dehydration, pneumonia, appendicitis, skin infections, mood disorders, and epilepsy). For each condition, we calculated rates of all-cause readmissions and rates of revisits (readmission or presentation to the emergency department) within 30 and 60 days of discharge. We used mixed logistic models to estimate hospital-level risk-standardized 30-day revisit rates and to identify hospitals that had performance statistically different from the group mean. Thirty-day readmission rates were low (1% of hospitals labeled as different from the mean on 30-day risk-standardized revisit rates was mood disorders (4.2% of hospitals [n = 15], range of hospital performance 6.3%-15.9%). We found that when comparing hospitals' performances to the average, few hospitals that care for children are identified as high- or low-performers for revisits, even for common pediatric diagnoses, likely due to low hospital volumes. This limits the usefulness of condition-specific readmission or revisit measures in pediatric quality measurement.

  14. Early Development Economics Debates Revisited

    OpenAIRE

    Alacevich, Michele

    2007-01-01

    Development economics in its early years created the image of a fierce fight between advocates of contrasting theories or approaches- "balanced growth" vs. "unbalanced growth" or "program loans" vs. "project loans." This view has the merit to highlight such conflicts in great detail; yet it fails to take into account the reality of development economics as it was practiced in the field. Th...

  15. Gastric schwannomas revisited: has precise preoperative diagnosis become feasible?

    Science.gov (United States)

    Fujiwara, Shinichi; Nakajima, Kiyokazu; Nishida, Toshirou; Takahashi, Tsuyoshi; Kurokawa, Yukinori; Yamasaki, Makoto; Miyata, Hiroshi; Takiguchi, Shuji; Mori, Masaki; Doki, Yuichiro

    2013-07-01

    Gastric schwannomas are not common but are clinically important in terms of differential diagnosis from other submucosal lesions. The precise preoperative diagnosis, however, has been challenging mainly owing to the lack of specific findings in conventional imaging studies. The aim of this study was to revisit the possibilities and limitations of modern preoperative diagnostic modalities for gastric schwannomas. Fourteen consecutive patients with a final pathological diagnosis of gastric schwannoma were retrospectively analyzed. Data included demographics, preoperative imaging studies/diagnosis, surgery, histopathology, and follow-up results. The series included 6 males and 8 females, with a median age of 49 years (range 26-68 years). No symptoms were presented, except for 1 patient with epigastric pain. The tumors were located in the upper (n = 5), middle (3), and lower stomach (6), with a median size of 41 mm (range 20-75 mm). Twelve schwannomas (86%) showed homogeneous enhancement on computed tomography. Ulceration was seen on endoscopy in 4 of 12 available cases (33%). Positron emission tomography was performed in the last 4 patients, showing fluorodeoxy-glucose uptake in all cases (100%). A preoperative diagnosis of schwannoma was not obtained in the majority of cases (13/14, 93%); only 1 case was correctly diagnosed, by endoscopic aspiration cytology. Laparoscopic partial gastrectomy was attempted and completed in 13 cases. The patients have been followed up for 4.7 years (range 2.1-20.3 years), with no recurrencesor metastases and acceptable gastrointestinal function. The precise preoperative diagnosis of gastric schwannomas remains difficult even with modern imaging studies. Surgery, therefore, should be positively considered for patients without a conclusive preoperative diagnosis.

  16. Sloan Digital Sky Survey Photometric Calibration Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Marriner, John; /Fermilab

    2012-06-29

    The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

  17. Ozone measurements with meteors: a revisit

    Science.gov (United States)

    Ye, Quan-Zhi; Han, Summer Xia

    2017-11-01

    Understanding the role of ozone in the mesosphere/lower thermosphere (MLT) region is essential for understanding the atmospheric processes in the upper atmosphere. Earlier studies have shown that it is possible to use overdense meteor trails to measure ozone concentration in the meteor region. Here, we revisit this topic by comparing a compilation of radar observations to satellite measurements. We observe a modest agreement between the values derived from these two methods, which confirm the usefulness of the meteor trail technique for measuring ozone content at certain heights in the MLT region. Future simultaneous measurements will help quantifying the performance of this technique.

  18. Large J expansion in ABJM theory revisited.

    Science.gov (United States)

    Dimov, H; Mladenov, S; Rashkov, R C

    Recently there has been progress in the computation of the anomalous dimensions of gauge theory operators at strong coupling by making use of the AdS/CFT correspondence. On the string theory side they are given by dispersion relations in the semiclassical regime. We revisit the problem of a large-charge expansion of the dispersion relations for simple semiclassical strings in an [Formula: see text] background. We present the calculation of the corresponding anomalous dimensions of the gauge theory operators to an arbitrary order using three different methods. Although the results of the three methods look different, power series expansions show their consistency.

  19. Revisiting the texture zero neutrino mass matrices

    Science.gov (United States)

    Singh, Madan; Ahuja, Gulsheen; Gupta, Manmohan

    2016-12-01

    In the light of refined and large measurements of the reactor mixing angle θ, we have revisited the texture three- and two-zero neutrino mass matrices in the flavor basis. For Majorana neutrinos, it has been explicitly shown that all the texture three-zero mass matrices remain ruled out. Further, for both normal and inverted mass ordering, for the texture two-zero neutrino mass matrices one finds interesting constraints on the Dirac-like CP-violating phase δ and Majorana phases ρ and σ.

  20. Revisiting fifth forces in the Galileon model

    Energy Technology Data Exchange (ETDEWEB)

    Burrage, Clare [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie; Seery, David [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy

    2010-05-15

    A Galileon field is one which obeys a spacetime generalization of the non- relativistic Galilean invariance. Such a field may possess non-canonical kinetic terms, but ghost-free theories with a well-defined Cauchy problem exist, constructed using a finite number of relevant operators. The interactions of this scalar with matter are hidden by the Vainshtein effect, causing the Galileon to become weakly coupled near heavy sources. We revisit estimates of the fifth force mediated by a Galileon field, and show that the parameters of the model are less constrained by experiment than previously supposed. (orig.)

  1. Working School Children in a Nigerian Community: Revisiting the ...

    African Journals Online (AJOL)

    Working School Children in a Nigerian Community: Revisiting the Issues. ... work on school performance and health consequences of child labour among school children in a rapidly ... The academic records of the students were also reviewed.

  2. Containment Revisited: An Old Approach to Future Challenges

    National Research Council Canada - National Science Library

    Lindamood, Brian

    2002-01-01

    .... The global nature of the new world order provides a grand setting for a revisit to Kennan's thoughts, giving America an unprecedented opportunity to secure itself and her allies without the 'rapid...

  3. Perspectives for in situ Scanning Tunnel Microscopic Imaging of Proteins at HOPG surfaces

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Thuesen, Marianne Hallberg; Møller, Per

    1996-01-01

    potentials on in situ potentiostatic control and releases nm size HOPG scrap bits. These are clearly different in shape from the ex situ imaged molecular-size structures. Laccase could not, however, be imaged by in situ STM, most likely due to structural incompatibility between hydrophobic HOPG surface......We have investigated the behaviour of the four-copper fungal metalloenzyme laccase (MW~68kDa) at highly oriented pyrolytic graphite (HOPG) surfaces by ex situ and in situ STM. The four copper atoms ar suited to stimulate long-range inelastic tunnel modes through the protein. The proteins forms...... crystalline or amorphous structures of micro-meter lateral extension during evaporation of aqueous laccase solution at low ionic strength. Individual molecular-size structures distinct from the HOPG background, and possibly arising from tip dislodging can also be imaged. The HOPG surface cracks at certain...

  4. Ground Zero revisits shape outbreaks: Zika and beyond

    CERN Document Server

    Manrique, Pedro D; Johnson, Neil F

    2016-01-01

    During an infection outbreak, many people continue to revisit Ground Zero - such as the one square mile of Miami involved in the current Zika outbreak- for work, family or social reasons. Public health planning must account for the counterintuitive ways in which this human flow affects the outbreak's duration, severity and time-to-peak. Managing this flow of revisits can allow the outbreak's evolution to be tailored.

  5. Kanter revisited: Gender, power and (in)visibility

    OpenAIRE

    Lewis, P.; Simpson, R

    2012-01-01

    This is the accepted version of the following article: Lewis, P. and Simpson, R. (2012), Kanter Revisited: Gender, Power and (In)Visibility. International Journal of Management Reviews, 14: 141–158., which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/j.1468-2370.2011.00327.x/abstract. This paper revisits Kanter's (1977) seminal work Men and Women of the Corporation, rereading her account of numerical advantage and disadvantage through a poststructuralist l...

  6. The Association Between Use of Brain CT for Atraumatic Headache and 30-Day Emergency Department Revisitation.

    Science.gov (United States)

    Patterson, Brian W; Pang, Peter S; AlKhawam, Lora; Hamedani, Azita G; Mendonca, Eneida A; Zhao, Ying-Qi; Venkatesh, Arjun K

    2016-12-01

    The purpose of this article is to describe the association between initial CT for atraumatic headache and repeat emergency department (ED) visitation within 30 days of ED discharge. A retrospective observational study was performed at an academic urban ED with more than 85,000 annual visits. All adult patients with a chief complaint of headache from January through December 2010 who were discharged after ED evaluation were included in the analysis. Patients were excluded if they were transferred, died in the ED, or had a diagnosis indicating a traumatic mechanism. A propensity score-matched logistic regression model was used to determine whether the use of brain CT was associated with the primary outcome of ED revisitation within 30 days, controlling for potential confounding variables. Of 80,619 total patient visits to the ED during the study period, 922 ED discharges with a chief complaint of headache were included. A total of 139 (15.1%) patients revisited within 30 days. The return rate was 11.2% among patients who underwent CT at their initial visit and 21.1% among those who did not. In the adjusted analysis, controlling for age, race, sex, insurance status, triage vital signs, laboratory values, and triage pain level, the odds ratio for revisitation given CT performance was 0.49 (95% CI, 0.27-0.86). After adjustment for clinical factors, we found that patients who underwent a brain CT examination for atraumatic headache at an initial ED visit were less likely to return to the ED within 30 days. Future appropriate use quality metrics regarding ED imaging use may need to incorporate downstream health care use.

  7. Revisit rates and associated costs after an emergency department encounter: a multistate analysis.

    Science.gov (United States)

    Duseja, Reena; Bardach, Naomi S; Lin, Grace A; Yazdany, Jinoos; Dean, Mitzi L; Clay, Theodore H; Boscardin, W John; Dudley, R Adams

    2015-06-02

    Return visits to the emergency department (ED) or hospital after an index ED visit strain the health system, but information about rates and determinants of revisits is limited. To describe revisit rates, variation in revisit rates by diagnosis and state, and associated costs. Observational study using the Healthcare Cost and Utilization Project databases. 6 U.S. states. Adults with ED visits between 2006 and 2010. Revisit rates and costs. Within 3 days of an index ED visit, 8.2% of patients had a revisit; 32% of those revisits occurred at a different institution. Revisit rates varied by diagnosis, with skin infections having the highest rate (23.1% [95% CI, 22.3% to 23.9%]). Revisit rates also varied by state. For skin infections, Florida had higher risk-adjusted revisit rates (24.8% [CI, 23.5% to 26.2%]) than Nebraska (10.6% [CI, 9.2% to 12.1%]). In Florida, the only state with complete cost data, total revisit costs for the 19.8% of patients with a revisit within 30 days were 118% of total index ED visit costs for all patients (including those with and without a revisit). Whether a revisit reflects inadequate access to primary care, a planned revisit, the patient's nonadherence to ED recommendations, or poor-quality care at the initial ED visit remains unknown. Revisits after an index ED encounter are more frequent than previously reported, in part because many occur outside the index institution. Among ED patients in Florida, more resources are spent on revisits than on index ED visits. Agency for Healthcare Research and Quality.

  8. Complete Genome sequence of Burkholderia phymatum STM815, a broad host range and efficient nitrogen-fixing symbiont of Mimosa species

    Energy Technology Data Exchange (ETDEWEB)

    Moulin, Lionel [UMR, France; Klonowska, Agnieszka [UMR, France; Caroline, Bournaud [UMR, France; Booth, Kristina [University of Massachusetts; Vriezen, Jan A.C. [University of Massachusetts; Melkonian, Remy [UMR, France; James, Euan [James Hutton Institute, Dundee, United Kingdom; Young, Peter W. [University of York, United Kingdom; Bena, Gilles [UMR, France; Hauser, Loren John [ORNL; Land, Miriam L [ORNL; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Bruce, David [Los Alamos National Laboratory (LANL); Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); Copeland, A [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Lizotte-Waniewski, Michelle [University of Massachusetts; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Riley, Monica [Woods Hole Oceanographic Institution (WHOI), Woods Hole

    2014-01-01

    Burkholderia phymatum is a soil bacterium able to develop a nitrogen-fixing symbiosis with species of the legume genus Mimosa, and is frequently found associated specifically with Mimosa pudica. The type strain of the species, STM 815T, was isolated from a root nodule in French Guiana in 2000. The strain is an aerobic, motile, non-spore forming, Gram-negative rod, and is a highly competitive strain for nodulation compared to other Mimosa symbionts, as it also nodulates a broad range of other legume genera and species. The 8,676,562 bp genome is composed of two chromosomes (3,479,187 and 2,697,374 bp), a megaplasmid (1,904,893 bp) and a plasmid hosting the symbiotic functions (595,108 bp).

  9. "Ant-egg" cataract revisited

    DEFF Research Database (Denmark)

    Clemmensen, Kåre; Enghild, Jan J; Ivarsen, Anders

    2017-01-01

    PURPOSE: Hereditary congenital cataract varies immensely concerning location and form of the lens opacities. A specific and very rare phenotype is called "ant-egg" cataract first described in 1900. "Ant-eggs" have previously been examined using light microscopy, backscattered electron imaging and X......-ray scans and electron microscopy. The purpose of this study was to further characterize "ant-egg" cataract using modern technology and display the history of the "ant-eggs" after cataract extraction. METHODS: "Ant-eggs" were examined using Heidelberg SPECTRALIS Optical Coherence Tomography (OCT......-egg" structures in "ant-egg" cataract. Eighteen of these proteins are not natively found in the human lens. Moreover, "ant-eggs" do not vary over time, after cataract extraction, regarding size and location....

  10. "Ant-egg" cataract revisited.

    Science.gov (United States)

    Clemmensen, Kåre; Enghild, Jan J; Ivarsen, Anders; Riise, Ruth; Vorum, Henrik; Heegaard, Steffen

    2017-01-01

    Hereditary congenital cataract varies immensely concerning location and form of the lens opacities. A specific and very rare phenotype is called "ant-egg" cataract first described in 1900. "Ant-eggs" have previously been examined using light microscopy, backscattered electron imaging and X-ray scans and electron microscopy. The purpose of this study was to further characterize "ant-egg" cataract using modern technology and display the history of the "ant-eggs" after cataract extraction. "Ant-eggs" were examined using Heidelberg SPECTRALIS Optical Coherence Tomography (OCT)(Heidelberg Engineering, Heidelberg, Germany). Ten "ant-eggs" were extracted; four of these as well as control tissue were analyzed by mass spectrometry (AB Sciex). Proteins were identified and their approximate abundances were determined. Immunohistochemical staining was carried out on the remaining "ant-eggs" for cytokeratin and S100. In anterior OCT-images, the "ant-egg" structures are localized on the iris. Comparative pictures showed that they stayed in the same location for more than 45 years. Mass spectrometry of "ant-eggs" yielded a proteome of 56 different proteins. Eighteen of the 56 "ant-egg" proteins (32 %) were neither present in our controls nor in a known fetal lens proteome. Among these were cytokeratin and Matrix-Gla protein. Immunohistochemical reactions were positive for cytokeratin and S100. This study demonstrates the previously unknown protein composition of the "ant-egg" structures in "ant-egg" cataract. Eighteen of these proteins are not natively found in the human lens. Moreover, "ant-eggs" do not vary over time, after cataract extraction, regarding size and location.

  11. Epitaxial deposition of silver ultrafine nano-clusters on defect-free surfaces of HOPG-derived few-layer graphene in a UHV multi-chamber by in-situ STM, ex-situ XPS and ab initio calculations

    CSIR Research Space (South Africa)

    Ndlovu, GF

    2012-03-01

    Full Text Available ) in conjunction with X-ray photoelectron spectroscopy. The energetics of the Ag clusters was determined by DFT simulations. The Ag clusters appeared spherical with size distribution averaging approximately 2 nm in diameter. STM revealed the preferred site...

  12. Faster than "g", Revisited with High-Speed Imaging

    Science.gov (United States)

    Vollmer, Michael; Mollmann, Klaus-Peter

    2012-01-01

    The introduction of modern high-speed cameras in physics teaching provides a tool not only for easy visualization, but also for quantitative analysis of many simple though fast occurring phenomena. As an example, we present a very well-known demonstration experiment--sometimes also discussed in the context of falling chimneys--which is commonly…

  13. The NRT2.5 and NRT2.6 genes are involved in growth promotion of Arabidopsis by the plant growth-promoting rhizobacterium (PGPR) strain Phyllobacterium brassicacearum STM196.

    Science.gov (United States)

    Kechid, Maya; Desbrosses, Guilhem; Rokhsi, Wafaa; Varoquaux, Fabrice; Djekoun, Abdelhamid; Touraine, Bruno

    2013-04-01

    The Phyllobacterium brassicacearum STM196 strain stimulates Arabidopsis thaliana growth and antagonizes high nitrate inhibition of lateral root development. A previous study identified two STM196-responsive genes, NRT2.5 and NRT2.6 (Mantelin et al., 2006, Planta 223: 591-603). We investigated the role of NRT2.5 and NRT2.6 in the plant response to STM196 using single and double Arabidopsis mutants. The single mutants were also crossed with an nrt2.1 mutant, lacking the major nitrate root transporter, to distinguish the effects of NRT2.5 and NRT2.6 from potential indirect effects of nitrate pools. The nrt2.5 and nrt2.6 mutations abolished the plant growth and root system architecture responses to STM196. The determination of nitrate content revealed that NRT2.5 and NRT2.6 do not play an important role in nitrate distribution between plant organs. Conversely, NRT2.5 and NRT2.6 appeared to play a role in the plant response independent of nitrate uptake. Using a nitrate reductase mutant, it was confirmed that the NRT2.5/NRT2.6-dependent plant signalling pathway is independent of nitrate-dependent regulation of root development. Our findings demonstrate that NRT2.5 and NRT2.6, which are preferentially expressed in leaves, play an essential role in plant growth promotion by the rhizospheric bacterium STM196. No claim to original US government works. New Phytologist © 2013 New Phytologist Trust.

  14. The Holstein polaron problem revisited

    Science.gov (United States)

    Tayebi, Amin; Zelevinsky, Vladimir

    2016-06-01

    The Holstein Hamiltonian was proposed half a century ago; since then, decades of research have come up empty handed in the pursuit of a closed-form solution. An exact solution to the two-site Holstein model is presented in this paper. The obtained results provide a clear image of the Hamiltonian structure and allow for the investigation of the symmetry, energy level crossings and polaronic characteristics of the system. The main mathematical tool is a three-term recurrence relation between the wave function amplitudes, which was obtained using the properties of a family of orthogonal functions, namely the Poisson-Charlier polynomials. It is shown that, with the appropriate choice of basis, the eigenfunctions of the problem naturally fall into two families (parities) associated with the discrete {{{Z}}}2 symmetry of the Hamiltonian. The asymptotic solution to the recurrence relation is found by using the Birkhoff expansion. The asymptotic sets the truncation criterion for the wave function, which ensures the accurate calculation of the energy levels for any strength of electron-phonon interaction. The level crossing of states with different parities is discussed and the exact points of broken symmetry are found analytically. The results are used as the building blocks for studying a four-site system. The inherited symmetries lead to the formation of a sparse matrix that is convenient for numerical calculations.

  15. Resolution of Reflection Seismic Data Revisited

    DEFF Research Database (Denmark)

    Hansen, Thomas Mejer; Mosegaard, Klaus; Zunino, Andrea

    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...... wavelength of the wavelet within the thin layer. Using a simple thin-layer parameterization Widess (1973) demonstrated that thin layers with thickness less that around λb/8 cannot be resolved from seismic data independent of the noise level. This has results since been widely adopted as a commonly accepted....... In general, we discuss that the resolution of reflection seismic data is controlled by the noise level and the a priori information available...

  16. Revisiting kaon physics in general Z scenario

    Directory of Open Access Journals (Sweden)

    Motoi Endo

    2017-08-01

    Full Text Available New physics contributions to the Z penguin are revisited in the light of the recently-reported discrepancy of the direct CP violation in K→ππ. Interference effects between the standard model and new physics contributions to ΔS=2 observables are taken into account. Although the effects are overlooked in the literature, they make experimental bounds significantly severer. It is shown that the new physics contributions must be tuned to enhance B(KL→π0νν¯, if the discrepancy of the direct CP violation is explained with satisfying the experimental constraints. The branching ratio can be as large as 6×10−10 when the contributions are tuned at the 10% level.

  17. Electrostatic instabilities in a mirror trap revisited

    Science.gov (United States)

    Kotelnikov, Igor A.; Chernoshtanov, Ivan S.; Prikhodko, Vadim V.

    2017-12-01

    The conditions for the stabilization of the Drift-Cyclotron Loss-Cone (DCLC) and Double-Humped (DH) microinstabilities in a mirror trap are critically revisited assuming the plasma is confined in the kinetic regime, which is characterized by an empty loss cone. The temperature of warm ions, necessary for stabilization of the DH instability, is calculated. The fraction of warm ions necessary to stabilize the DCLC instability at a given radial density gradient is calculated. Assuming the wavelength is much shorter than the Larmor radius, a simple criterion for the stability of drift-cyclotron loss-cone oscillations is derived whose accuracy is verified by comparison with the solution of the exact dispersion equation and with known experimental data obtained in the past decades in PR-6, 2XII, 2XIIB, TMX, and TMX-U devices for plasma confinement.

  18. The Faraday effect revisited General theory

    CERN Document Server

    Cornean, H D; Pedersen, T G

    2005-01-01

    This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. For free electrons, the transverse conductivity can be explicitly computed and coincides with the classical result. In the general case, using magnetic perturbation theory, the conductivity tensor is expanded in powers of the strength of the magnetic field $B$. Then the linear term in $B$ of this expansion is written down in terms of the zero magnetic field Green function and the zero field current operator. In the periodic case, the linear term in $B$ of the conductivity tensor is expressed in terms of zero magnetic field Bloch functions and energies. No derivatives with respect to the quasimomentum appear and thereby all ambiguities are removed, in contrast to earlier work.

  19. Revisiting monotop production at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Boucheneb, Idir [Université de Lyon, Université Lyon 1,F-69622 Villeurbanne (France); Cacciapaglia, Giacomo; Deandrea, Aldo [Université de Lyon, Université Lyon 1,F-69622 Villeurbanne (France); Institut de Physique Nucléaire de Lyon, CNRS/IN2P3, UMR5822,F-69622 Villeurbanne Cedex (France); Fuks, Benjamin [CERN, PH-TH,CH-1211 Geneva 23 (Switzerland); Institut Pluridisciplinaire Hubert Curien/Département Recherches Subatomiques,Université de Strasbourg/CNRS-IN2P3, 23 rue du Loess, F-67037 Strasbourg (France)

    2015-01-07

    Scenarios of new physics where a single top quark can be produced in association with large missing energy (monotop) have been recently studied both from the theoretical point of view and by experimental collaborations. We revisit the originally proposed monotop setup by embedding the effective couplings of the top quark in an SU(2){sub L} invariant formalism. We show that minimality selects one model for each of the possible production mechanisms: a scalar field coupling to a right-handed top quark and an invisible fermion when the monotop system is resonantly produced, and a vector field mediating the interactions of a dark sector to right-handed quarks for the non-resonant production mode. We study in detail constraints on the second class of scenarios, originating from contributions to standard single top processes when the mediator is lighter than the top quark and from the dark matter relic abundance when the mediator is heavier than the top quark.

  20. Post-Inflationary Gravitino Production Revisited

    CERN Document Server

    Ellis, John; Nanopoulos, Dimitri V.; Olive, Keith A.; Peloso, Marco

    2016-01-01

    We revisit gravitino production following inflation. As a first step, we review the standard calculation of gravitino production in the thermal plasma formed at the end of post-inflationary reheating when the inflaton has completely decayed. Next we consider gravitino production prior to the completion of reheating, assuming that the inflaton decay products thermalize instantaneously while they are still dilute. We then argue that instantaneous thermalization is in general a good approximation, and also show that the contribution of non-thermal gravitino production via the collisions of inflaton decay products prior to thermalization is relatively small. Our final estimate of the gravitino-to-entropy ratio is approximated well by a standard calculation of gravitino production in the post-inflationary thermal plasma assuming total instantaneous decay and thermalization at a time $t \\simeq 1.2/\\Gamma_\\phi$. Finally, in light of our calculations, we consider potential implications of upper limits on the gravitin...

  1. Damage caps and defensive medicine, revisited.

    Science.gov (United States)

    Paik, Myungho; Black, Bernard; Hyman, David A

    2017-01-01

    Does tort reform reduce defensive medicine and thus healthcare spending? Several (though not all) prior studies, using a difference-in-differences (DiD) approach, find lower Medicare spending for hospital care after states adopt caps on non-economic or total damages ("damage caps"), during the "second" reform wave of the mid-1980s. We re-examine this issue in several ways. We study the nine states that adopted caps during the "third reform wave," from 2002 to 2005. We find that damage caps have no significant impact on Medicare Part A spending, but predict roughly 4% higher Medicare Part B spending. We then revisit the 1980s caps, and find no evidence of a post-adoption drop (or rise) in spending for these caps. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. The size of the sync basin revisited

    Science.gov (United States)

    Delabays, Robin; Tyloo, Melvyn; Jacquod, Philippe

    2017-10-01

    In dynamical systems, the full stability of fixed point solutions is determined by their basins of attraction. Characterizing the structure of these basins is, in general, a complicated task, especially in high dimensionality. Recent works have advocated to quantify the non-linear stability of fixed points of dynamical systems through the relative volumes of the associated basins of attraction [Wiley et al., Chaos 16, 015103 (2006) and Menck et al. Nat. Phys. 9, 89 (2013)]. Here, we revisit this issue and propose an efficient numerical method to estimate these volumes. The algorithm first identifies stable fixed points. Second, a set of initial conditions is considered that are randomly distributed at the surface of hypercubes centered on each fixed point. These initial conditions are dynamically evolved. The linear size of each basin of attraction is finally determined by the proportion of initial conditions which converge back to the fixed point. Armed with this algorithm, we revisit the problem considered by Wiley et al. in a seminal paper [Chaos 16, 015103 (2006)] that inspired the title of the present manuscript and consider the equal-frequency Kuramoto model on a cycle. Fixed points of this model are characterized by an integer winding number q and the number n of oscillators. We find that the basin volumes scale as (1-4 q /n ) n , contrasting with the Gaussian behavior postulated in the study by Wiley et al.. Finally, we show the applicability of our method to complex models of coupled oscillators with different natural frequencies and on meshed networks.

  3. The Lumbar Lordosis in Males and Females, Revisited.

    Directory of Open Access Journals (Sweden)

    Ori Hay

    Full Text Available Whether differences exist in male and female lumbar lordosis has been debated by researchers who are divided as to the nature of variations in the spinal curve, their origin, reasoning, and implications from a morphological, functional and evolutionary perspective. Evaluation of the spinal curvature is constructive in understanding the evolution of the spine, as well as its pathology, planning of surgical procedures, monitoring its progression and treatment of spinal deformities. The aim of the current study was to revisit the nature of lumbar curve in males and females.Our new automated method uses CT imaging of the spine to measure lumbar curvature in males and females. The curves extracted from 158 individuals were based on the spinal canal, thus avoiding traditional pitfalls of using bone features for curve estimation. The model analysis was carried out on the entire curve, whereby both local and global descriptors were examined in a single framework. Six parameters were calculated: segment length, curve length, curvedness, lordosis peak location, lordosis cranial peak height, and lordosis caudal peak height.Compared to males, the female spine manifested a statistically significant greater curvature, a caudally located lordotic peak, and greater cranial peak height. As caudal peak height is similar for males and females, the illusion of deeper lordosis among females is due partially to the fact that the upper part of the female lumbar curve is positioned more dorsally (more backwardly inclined.Males and females manifest different lumbar curve shape, yet similar amount of inward curving (lordosis. The morphological characteristics of the female spine were probably developed to reduce stress on the vertebral elements during pregnancy and nursing.

  4. Superresolution Imaging Using Resonant Multiples

    KAUST Repository

    Guo, Bowen

    2017-12-22

    A resonant multiple is defined as a multiple reflection that revisits the same subsurface location along coincident reflection raypaths. We show that resonant first-order multiples can be migrated with either Kirchhoff or wave-equation migration methods to give images with approximately twice the spatial resolution compared to post-stack primary-reflection images. A moveout-correction stacking method is proposed to enhance the signal-to-noise ratios (SNRs) of the resonant multiples before superresolution migration. The effectiveness of this procedure is validated by synthetic and field data tests.

  5. A two-step dilution tris-egg yolk extender containing Equex STM significantly improves sperm cryopreservation in the African wild dog (Lycaon pictus).

    Science.gov (United States)

    Van den Berghe, Femke; Paris, Monique Christina Johanna; Briggs, Michael Brent; Farstad, Wenche Kristin; Paris, Damien Boyd Bertrand Paul

    2017-12-27

    Conservation management of endangered African wild dogs (AWD; Lycaon pictus) can benefit greatly from development of sperm freezing and artificial insemination. Previous freezing attempts yielded nearly 0% motile sperm within 2 h of thawing. In this study, two canine freezing protocols were tested: Protocol 1: a one-step dilution in TRIS-20% egg yolk containing 8% glycerol; and Protocol 2: a two-step dilution in TRIS-20% egg yolk containing a final extender concentration of 5% glycerol and 0.5% Equex STM, coupled with a TRIS-citrate-fructose thawing solution. Semen was collected by electroejaculation from n = 24 AWDs, of which eight ejaculates of sufficient quality (four good quality with initial sperm motility of 75.0 ± 4.4% and four poor quality; showing rapid decrease in sperm motility to 3.3 ± 3.3% prior to freezing) were frozen. For good quality samples, motility and sperm motility index persisted for up to 8 h for Protocol 2, and was higher between 2 and 6 h after thawing with a decrease from 4 h of incubation. Motility dropped to nearly 0% after 2 h incubation for Protocol 1. Viability was higher for Protocol 2 throughout the 8 h of incubation, with a decrease after 6 h, compared to 4 h for Protocol 1. Acrosome integrity was higher for Protocol 2 throughout post-thaw incubation, with a decrease after 2 h for both protocols. Protocols did not differ in normal sperm morphology or DNA integrity. Poor quality samples yielded similar results, except for acrosome integrity, which declined for Protocol 2. In conclusion, a two-step dilution in TRIS-egg yolk-glycerol extender containing Equex STM yields significantly improved post-thaw quality and longevity of AWD spermatozoa, making it suitable for sperm banking and artificial insemination initiatives. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Nanoscopic platinum particles on TiO{sub 2}(110). STM and point-contact studies on the chemical and photosensitivity; Nanoskopische Platin-Teilchen auf TiO{sub 2}(110). STM- und Punktkontaktuntersuchungen zur chemischen und Photosensitivitaet

    Energy Technology Data Exchange (ETDEWEB)

    Koelbach, Johannes Micha

    2009-06-23

    In the ultra high vacuum produced nanoscopical platinum particles on TiO{sub 2}(110)- single crystal surfaces are contacted with the tunneltip of a raster tunnel microscope, and the chemical as well as photo sensitivity of an individual hetero contact are determined. For the experiments a UHV equipment was developed, equipped with methods to the controlled preparation and surface-analytic techniques (LEED, AES and STM). Platinum is resistively evaporated and thus small platinum particles with a size of about 8nm are generated on the pure titanium dioxide surface and characterized by STM and STS. A new developed oxygen source based on zirconoxide ceramics enables in-situ experiments for undisturbed determination of current-voltage characteristics in the tunneling and contact mode. A special preamplifier with controllable range of amplification is applied. Applying a voltage to the ceramic oxygen can be let into the UHV chamber by the oxygen source and the partial pressure can be adjusted within the range of 1.10{sup -10} mbar to 1.10{sup -5} mbar. The effect of the oxygen on the electrical characteristics of the Pt/TiO{sub 2}-contacts was proven. The clear dependence of the current-voltage characteristics on the oxygen partial pressure can be explained as a result of interface states due to the dissociation and adsorption of the oxygen, which determine the electrical characteristic of the contact. Schottky barriere heights and quality parameters were determined and compared with values of macroscopic surface contacts. For the investigations of the photo sensitivity a special STM head was developed, which enables the coupling of laser light with a wavelength of 413.1 nm. Irradiation of the nanoscopical Pt/TiO{sub 2}-contacts changes the current-voltage characteristics as well. The results of the power-dependent measurements refer to a temperature effect, that dominates the photoelectric effect. The combined power-and oxygen partial pressure dependent measurements are

  7. Revisit laser scanning fluorescence microscopy performance under fluorescence-lifetime-limited regime

    Science.gov (United States)

    Chan, Antony C.; Wong, Terence T. W.; Wong, Kenneth K. Y.; Lam, Edmund Y.; Tsia, Kevin K.

    2014-03-01

    Continuing desire for higher-speed laser scanning fluorescence microscopy (LSFM) and progressive advancement in ultrafast and sensitive photodetectors might imply that our conventional understanding of LSFM is not adequate when approaching to the intrinsic speed limit — fluorescence lifetime. In this regard, we here revisit the theoretical framework of LSFM and evaluate its general performance in lifetime-limited and noise-limited regimes. Our model suggests that there still exists an order-of-magnitude gap between the current LSFM speed and the intrinsic limit. An imaging frame rate of > 100 kHz could be viable with the emerging laser-scanning techniques using ultrafast wavelength-swept sources, or optical time-stretch.

  8. Temperature-induced structural evolution of Sm nanoparticles on Al2O3 thin film: An in-situ investigation using SRPES, XPS and STM

    Science.gov (United States)

    Xu, Qian; Hu, Shanwei; Wang, Weijia; Wang, Yan; Ju, Huanxin; Zhu, Junfa

    2018-02-01

    The structural evolution of Sm nanoclusters on ultrathin film of Al2O3 epitaxially grown on Ni3Al(111) substrate at elevated temperatures was investigated in-situ using synchrotron radiation photoemission spectroscopy (SRPES), X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). The vapor-deposited metallic Sm onto the Al2O3 thin film at 300 K is partially oxidized, leading to the appearance of both Sm2+ and Sm3+ states at low coverages, due to the charge transfer from Sm to oxide film. The complete oxidation of the Sm, i.e., all Sm2+ converted to Sm3+, occurs when the sample is annealed to 500 K. Further annealing results in the diffusion of Sm into the Al2O3 lattice. At ∼900 K, the formation of a SmAlO3 complex is observed. However, this complex starts to decompose and desorb from the surface at temperature higher than 1200 K. Interestingly, it is found that Sm can promote the oxidation of Ni3Al substrate and thicken the alumina film when Sm is deposited at room temperature onto the Al2O3/Ni3Al(111) substrate followed by annealing in oxygen environment at ∼800 K.

  9. Pump-probe STM light emission spectroscopy for detection of photo-induced semiconductor-metal phase transition of VO2

    Science.gov (United States)

    Sakai, Joe; Katano, Satoshi; Kuwahara, Masashi; Uehara, Yoichi

    2017-10-01

    We attempted to observe pump-probe scanning tunneling microscopy (STM)-light emission (LE) from a VO2 thin film grown on a rutile TiO2(0 0 1) substrate, with an Ag tip fixed over a semiconducting domain. Laser pulses from a Ti:sapphire laser (wavelength 920 nm pulse width less than 1.5 ps) irradiated the tip-sample gap as pump and probe light sources. With a photon energy of 2.7 eV, suggesting phase transition from semiconducting monoclinic (M) to metallic rutile (R) phases in relation to the electronic band structure, faint LE was observed roughly 30 ps after the irradiation of the pump pulse, followed by retention for roughly 20 ps. The incident energy fluence of the pump pulse at the gap was five orders of magnitude lower than the threshold value for reported photo-induced M-R phase transition. The mechanism that makes it possible to reduce the threshold fluence is discussed.

  10. The Super-GUT CMSSM Revisited

    CERN Document Server

    Ellis, John

    2016-01-01

    We revisit minimal supersymmetric SU(5) grand unification (GUT) models in which the soft supersymmetry-breaking parameters of the minimal supersymmetric Standard Model (MSSM) are universal at some input scale, $M_{in}$, above the supersymmetric gauge coupling unification scale, $M_{GUT}$. As in the constrained MSSM (CMSSM), we assume that the scalar masses and gaugino masses have common values, $m_0$ and $m_{1/2}$ respectively, at $M_{in}$, as do the trilinear soft supersymmetry-breaking parameters $A_0$. Going beyond previous studies of such a super-GUT CMSSM scenario, we explore the constraints imposed by the lower limit on the proton lifetime and the LHC measurement of the Higgs mass, $m_h$. We find regions of $m_0$, $m_{1/2}$, $A_0$ and the parameters of the SU(5) superpotential that are compatible with these and other phenomenological constraints such as the density of cold dark matter, which we assume to be provided by the lightest neutralino. Typically, these allowed regions appear for $m_0$ and $m_{1/...

  11. Searle's"Dualism Revisited"

    Energy Technology Data Exchange (ETDEWEB)

    P., Henry

    2008-11-20

    A recent article in which John Searle claims to refute dualism is examined from a scientific perspective. John Searle begins his recent article 'Dualism Revisited' by stating his belief that the philosophical problem of consciousness has a scientific solution. He then claims to refute dualism. It is therefore appropriate to examine his arguments against dualism from a scientific perspective. Scientific physical theories contain two kinds of descriptions: (1) Descriptions of our empirical findings, expressed in an every-day language that allows us communicate to each other our sensory experiences pertaining to what we have done and what we have learned; and (2) Descriptions of a theoretical model, expressed in a mathematical language that allows us to communicate to each other certain ideas that exist in our mathematical imaginations, and that are believed to represent, within our streams of consciousness, certain aspects of reality that we deem to exist independently of their being perceived by any human observer. These two parts of our scientific description correspond to the two aspects of our general contemporary dualistic understanding of the total reality in which we are imbedded, namely the empirical-mental aspect and the theoretical-physical aspect. The duality question is whether this general dualistic understanding of ourselves should be regarded as false in some important philosophical or scientific sense.

  12. Pair Production Constraints on Superluminal Neutrinos Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.; /SLAC; Gardner, Susan; /Kentucky U.

    2012-02-16

    We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p{sup 2} can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

  13. Revisiting the survival mnemonic effect in children.

    Science.gov (United States)

    Pand eirada, Josefa N S; Pires, Luísa; Soares, Sandra C

    2014-04-29

    The survival processing paradigm is designed to explore the adaptive nature of memory functioning. The mnemonic advantage of processing information in fitness-relevant contexts, as has been demonstrated using this paradigm, is now well established, particularly in young adults; this phenomenon is often referred to as the "survival processing effect." In the current experiment, we revisited the investigation of this effect in children and tested it in a new cultural group, using a procedure that differs from the existing studies with children. A group of 40 Portuguese children rated the relevance of unrelated words to a survival and a new moving scenario. This encoding task was followed by a surprise free-recall task. Akin to what is typically found, survival processing produced better memory performance than the control condition (moving). These data put on firmer ground the idea that a mnemonic tuning to fitness-relevant encodings is present early in development. The theoretical importance of this result to the adaptive memory literature is discussed, as well as potential practical implications of this kind of approach to the study of memory in children.

  14. Revisiting the Survival Mnemonic Effect in Children

    Directory of Open Access Journals (Sweden)

    Josefa N. S. Pand Eirada

    2014-04-01

    Full Text Available The survival processing paradigm is designed to explore the adaptive nature of memory functioning. The mnemonic advantage of processing information in fitness-relevant contexts, as has been demonstrated using this paradigm, is now well established, particularly in young adults; this phenomenon is often referred to as the “survival processing effect.” In the current experiment, we revisited the investigation of this effect in children and tested it in a new cultural group, using a procedure that differs from the existing studies with children. A group of 40 Portuguese children rated the relevance of unrelated words to a survival and a new moving scenario. This encoding task was followed by a surprise free-recall task. Akin to what is typically found, survival processing produced better memory performance than the control condition (moving. These data put on firmer ground the idea that a mnemonic tuning to fitness-relevant encodings is present early in development. The theoretical importance of this result to the adaptive memory literature is discussed, as well as potential practical implications of this kind of approach to the study of memory in children.

  15. Revisiting CMB constraints on warm inflation

    Science.gov (United States)

    Arya, Richa; Dasgupta, Arnab; Goswami, Gaurav; Prasad, Jayanti; Rangarajan, Raghavan

    2018-02-01

    We revisit the constraints that Planck 2015 temperature, polarization and lensing data impose on the parameters of warm inflation. To this end, we study warm inflation driven by a single scalar field with a quartic self interaction potential in the weak dissipative regime. We analyse the effect of the parameters of warm inflation, namely, the inflaton self coupling λ and the inflaton dissipation parameter QP on the CMB angular power spectrum. We constrain λ and QP for 50 and 60 number of e-foldings with the full Planck 2015 data (TT, TE, EE + lowP and lensing) by performing a Markov-Chain Monte Carlo analysis using the publicly available code CosmoMC and obtain the joint as well as marginalized distributions of those parameters. We present our results in the form of mean and 68 % confidence limits on the parameters and also highlight the degeneracy between λ and QP in our analysis. From this analysis we show how warm inflation parameters can be well constrained using the Planck 2015 data.

  16. The super-GUT CMSSM revisited

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, John [King' s College London, Theoretical Physics and Cosmology Group, Department of Physics, London (United Kingdom); CERN, Theoretical Physics Department, Geneva (Switzerland); Evans, Jason L. [KIAS, School of Physics, Seoul (Korea, Republic of); Mustafayev, Azar; Nagata, Natsumi; Olive, Keith A. [University of Minnesota, William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, Minneapolis, MN (United States)

    2016-11-15

    We revisit minimal supersymmetric SU(5) grand unification (GUT) models in which the soft supersymmetry-breaking parameters of the minimal supersymmetric Standard Model (MSSM) are universal at some input scale, M{sub in}, above the supersymmetric gauge-coupling unification scale, M{sub GUT}. As in the constrained MSSM (CMSSM), we assume that the scalar masses and gaugino masses have common values, m{sub 0} and m{sub 1/2}, respectively, at M{sub in}, as do the trilinear soft supersymmetry-breaking parameters A{sub 0}. Going beyond previous studies of such a super-GUT CMSSM scenario, we explore the constraints imposed by the lower limit on the proton lifetime and the LHC measurement of the Higgs mass, m{sub h}. We find regions of m{sub 0}, m{sub 1/2}, A{sub 0} and the parameters of the SU(5) superpotential that are compatible with these and other phenomenological constraints such as the density of cold dark matter, which we assume to be provided by the lightest neutralino. Typically, these allowed regions appear for m{sub 0} and m{sub 1/2} in the multi-TeV region, for suitable values of the unknown SU(5) GUT-scale phases and superpotential couplings, and with the ratio of supersymmetric Higgs vacuum expectation values tanβ

  17. Hyperinflation in Brazil, Israel, and Nicaragua revisited

    Science.gov (United States)

    Szybisz, Martín A.; Szybisz, Leszek

    2017-01-01

    The aim of the present work is to address the description of hyperinflation regimens in economy. The spirals of hyperinflation developed in Brazil, Israel, and Nicaragua are revisited. This new analysis of data indicates that the episodes occurred in Brazil and Nicaragua can be understood within the frame of the model available in the literature, which is based on a nonlinear feedback (NLF) characterized by an exponent β > 0. In the NLF model the accumulated consumer price index carries a finite time singularity of the type 1 /(tc - t) (1 - β) / β determining a critical time tc at which the economy would crash. It is shown that in the case of Brazil the entire episode cannot be described with a unique set of parameters because the time series was strongly affected by a change of policy. This fact gives support to the ;so called; Lucas critique, who stated that model's parameters usually change once policy changes. On the other hand, such a model is not able to provide any tc in the case of the weaker hyperinflation occurred in Israel. It is shown that in this case the fit of data yields β → 0. This limit leads to the linear feedback formulation which does not predict any tc. An extension for the NLF model is suggested.

  18. Early-Transition Output Decline Revisited

    Directory of Open Access Journals (Sweden)

    Crt Kostevc

    2016-05-01

    Full Text Available In this paper we revisit the issue of aggregate output decline that took place in the early transition period. We propose an alternative explanation of output decline that is applicable to Central- and Eastern-European countries. In the first part of the paper we develop a simple dynamic general equilibrium model that builds on work by Gomulka and Lane (2001. In particular, we consider price liberalization, interpreted as elimination of distortionary taxation, as a trigger of the output decline. We show that price liberalization in interaction with heterogeneous adjustment costs and non-employment benefits lead to aggregate output decline and surge in wage inequality. While these patterns are consistent with actual dynamics in CEE countries, this model cannot generate output decline in all sectors. Instead sectors that were initially taxed even exhibit output growth. Thus, in the second part we consider an alternative general equilibrium model with only one production sector and two types of labor and distortion in a form of wage compression during the socialist era. The trigger for labor mobility and consequently output decline is wage liberalization. Assuming heterogeneity of workers in terms of adjustment costs and non-employment benefits can explain output decline in all industries.

  19. Meta-analysis in clinical trials revisited.

    Science.gov (United States)

    DerSimonian, Rebecca; Laird, Nan

    2015-11-01

    In this paper, we revisit a 1986 article we published in this Journal, Meta-Analysis in Clinical Trials, where we introduced a random-effects model to summarize the evidence about treatment efficacy from a number of related clinical trials. Because of its simplicity and ease of implementation, our approach has been widely used (with more than 12,000 citations to date) and the "DerSimonian and Laird method" is now often referred to as the 'standard approach' or a 'popular' method for meta-analysis in medical and clinical research. The method is especially useful for providing an overall effect estimate and for characterizing the heterogeneity of effects across a series of studies. Here, we review the background that led to the original 1986 article, briefly describe the random-effects approach for meta-analysis, explore its use in various settings and trends over time and recommend a refinement to the method using a robust variance estimator for testing overall effect. We conclude with a discussion of repurposing the method for Big Data meta-analysis and Genome Wide Association Studies for studying the importance of genetic variants in complex diseases. Published by Elsevier Inc.

  20. Revisiting the argument from fetal potential

    Directory of Open Access Journals (Sweden)

    Manninen Bertha

    2007-05-01

    Full Text Available Abstract One of the most famous, and most derided, arguments against the morality of abortion is the argument from potential, which maintains that the fetus' potential to become a person and enjoy the valuable life common to persons, entails that its destruction is prima facie morally impermissible. In this paper, I will revisit and offer a defense of the argument from potential. First, I will criticize the classical arguments proffered against the importance of fetal potential, specifically the arguments put forth by philosophers Peter Singer and David Boonin, by carefully unpacking the claims made in these arguments and illustrating why they are flawed. Secondly, I will maintain that fetal potential is morally relevant when it comes to the morality of abortion, but that it must be accorded a proper place in the argument. This proper place, however, cannot be found until we first answer a very important and complex question: we must first address the issue of personal identity, and when the fetus becomes the type of being who is relevantly identical to a future person. I will illustrate why the question of fetal potential can only be meaningfully addressed after we have first answered the question of personal identity and how it relates to the human fetus.

  1. Revisiting the relaxation dynamics of isolated pyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Montero, Raúl; Ovejas, Virginia; Fernández-Fernández, Marta; Longarte, Asier, E-mail: asier.longarte@ehu.es [Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao (Spain); Peralta Conde, Álvaro [Centro de Láseres Pulsados (CLPU), Edificio M3, Parque Científico, 37185 Villamayor (Spain)

    2014-07-07

    Herein, the interpretation of the femtosecond-scale temporal evolution of the pyrrole ion signal, after excitation in the 267–217 nm interval, recently published by our group [R. Montero, A. Peralta Conde, V. Ovejas, M. Fernández-Fernández, F. Castaño, J. R. Vázquez de Aldana, and A. Longarte, J. Chem. Phys.137, 064317 (2012)] is re-visited. The observation of a shift in the pyrrole{sup +} transient respect to zero delay reference, initially attributed to ultrafast dynamics on the πσ{sup *} type state (3s a{sub 1} ← π 1a{sub 2}), is demonstrated to be caused by the existence of pump + probe populated states, along the ionization process. The influence of these resonances in pump-prone ionization experiments, when multi-photon probes are used, and the significance of a proper zero-time reference, is discussed. The possibility of preparing the πσ{sup *} state by direct excitation is investigated by collecting 1 + 1 photoelectron spectra, at excitation wavelengths ranging from 255 to 219 nm. No conclusive evidences of ionization through this state are found.

  2. Titmuss and the gift relationship: altruism revisited.

    Science.gov (United States)

    Rapport, F L; Maggs, C J

    2002-12-01

    This paper revisits Richard Titmuss' 1970s blood donation model in the light of its 1997 reprint in order to consider whether we are justified in continuing to accept that the main reason for blood donation (and other donation types) is an altruistic desire to help others. This paper explores how others have examined the notion of altruism, before concentrating on two major elements of Titmuss' work: blood donors' motives to donate and the social implications of gift-giving in relation to the uniqueness of blood donation. Donor motivation is discussed in detail with particular reference to questions 4 and 5 of Titmuss' blood donor survey and through a critical appraisal approach to his work. Methodological inconsistencies are revealed in the design and implementation of the survey, as well as in Titmuss' list of blood donation's unique attributes, bringing into question the rigour of his findings. It may be that blood donors are altruistically motivated, but such conclusions cannot be drawn from this work. It is also unclear if 'altruism' can be shown in the example of blood donation or other donation types. We should reconsider the motivation behind gifting in health care in the light of these findings and ensure that evidence-based practice is consistent with methodological rigour. Nurses and other health professionals need to have a clearer understanding of concepts such as altruism in order to appreciate why people seek to donate.

  3. Revisiting Twomey's approximation for peak supersaturation

    Directory of Open Access Journals (Sweden)

    B. J. Shipway

    2015-04-01

    Full Text Available Twomey's seminal 1959 paper provided lower and upper bound approximations to the estimation of peak supersaturation within an updraft and thus provides the first closed expression for the number of nucleated cloud droplets. The form of this approximation is simple, but provides a surprisingly good estimate and has subsequently been employed in more sophisticated treatments of nucleation parametrization. In the current paper, we revisit the lower bound approximation of Twomey and make a small adjustment that can be used to obtain a more accurate calculation of peak supersaturation under all potential aerosol loadings and thermodynamic conditions. In order to make full use of this improved approximation, the underlying integro-differential equation for supersaturation evolution and the condition for calculating peak supersaturation are examined. A simple rearrangement of the algebra allows for an expression to be written down that can then be solved with a single lookup table with only one independent variable for an underlying lognormal aerosol population. While multimodal aerosol with N different dispersion characteristics requires 2N+1 inputs to calculate the activation fraction, only N of these one-dimensional lookup tables are needed. No additional information is required in the lookup table to deal with additional chemical, physical or thermodynamic properties. The resulting implementation provides a relatively simple, yet computationally cheap, physically based parametrization of droplet nucleation for use in climate and Numerical Weather Prediction models.

  4. The Einstein-Boltzmann equations revisited

    Science.gov (United States)

    Nadkarni-Ghosh, Sharvari; Refregier, Alexandre

    2017-10-01

    The linear Einstein-Boltzmann (E-B) equations describe the evolution of perturbations in the universe and its numerical solutions play a central role in cosmology. We revisit this system of differential equations and present a detailed investigation of its mathematical properties. For this purpose, we focus on a simplified set of equations aimed at describing the broad features of the matter power spectrum. We first perform an eigenvalue analysis and study the onset of oscillations in the system signalled by the transition from real to complex eigenvalues. We then provide a stability criterion of different numerical schemes for this linear system and estimate the associated step size. We elucidate the stiffness property of the E-B system and show how it can be characterized in terms of the eigenvalues. While the parameters of the system are time dependent making it non-autonomous, we define an adiabatic regime where the parameters vary slowly enough for the system to be quasi-autonomous. We summarize the different regimes of the system for these different criteria as function of wavenumber k and scalefactor a. We also provide a compendium of analytic solutions for all perturbation variables in six limits on the k-a plane and express them explicitly in terms of initial conditions. These results are aimed to help the further development and testing of numerical cosmological Boltzmann solvers.

  5. High-Resolution Imaging of Polyethylene Glycol Coated Dendrimers via Combined Atomic Force and Scanning Tunneling Microscopy

    Directory of Open Access Journals (Sweden)

    Shawn Riechers

    2015-01-01

    Full Text Available Dendrimers have shown great promise as drug delivery vehicles in recent years because they can be synthesized with designed size and functionalities for optimal transportation, targeting, and biocompatibility. One of the most well-known termini used for biocompatibility is polyethylene glycol (PEG, whose performance is affected by its actual conformation. However, the conformation of individual PEG bound to soft materials such as dendrimers has not been directly observed. Using atomic force microscopy (AFM and scanning tunneling microscopy (STM, this work characterizes the structure adopted by PEGylated dendrimers with the highest resolution reported to date. AFM imaging enables visualization of the individual dendrimers, as well as the differentiation and characterization of the dendrimer core and PEG shell. STM provides direct imaging of the PEG extensions with high-resolution. Collectively, this investigation provides important insight into the structure of coated dendrimers, which is crucial for the design and development of better drug delivery vehicles.

  6. Analysis and Calibration of in situ scanning tunnelling microscopy Images with atomic Resolution Influenced by Surface Drift Phenomena

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Møller, Per

    1994-01-01

    The influence of surface drift velocities on in situ scanning tunnelling microscopy (STM) experiments with atomic resolution is analysed experimentally and mathematically. Constant drift velocities much smaller than the speed of scanning can in many in situ STM experiments with atomic resolution...... result in an apparent surface reconstruction. It is shown that a surface atomic structure can be distorted and observed as another atomic structure entirely owing to a constant drift velocity in the plane of the surface. The image can be resolved mathematically and the components of the drift velocity...... as well as the vectors of the non-distorted surface lattice can be determined. The calibration of distances can thus be carried out also when the image is influenced by drift. Results with gold surfaces and graphite surfaces are analysed and discussed....

  7. Submolecular Electronic Mapping of Single Cysteine Molecules by in Situ Scanning Tunneling Imaging

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Chi, Qijin; Nazmutdinov, R. R.

    2009-01-01

    based on a slab model for the metal surface. The ordered monolayer offers a platform for submolecular scale electronic mapping that is an issue of fundamental interest but remains a challenge in STM imaging science and surface chemistry. Single Cys molecules were mapped as three electronic subunits......We have used L-Cysteine (Cys) as a model system to study the surface electronic structures of single molecules at the submolecular level in aqueous buffer solution by a combination of electrochemical scanning tunneling microscopy (in situ STM), electrochemistry including voltammetry...... contributed mainly from three chemical moieties: thiol (-SH), carboxylic (-COOH), and amine (-NH2) groups. The contrasts of the three subunits depend on the environment (e.g., pH), which affects the electronic structure of adsorbed species. From the DFT computations focused on single molecules, rational...

  8. Educational Administration and the Management of Knowledge: 1980 Revisited

    Science.gov (United States)

    Bates, Richard

    2013-01-01

    This paper revisits the thesis of a 1980 paper that suggested a new approach to educational administration based upon the New Sociology of Education. In particular it updates answers to the six key questions asked by that paper: what counts as knowledge; how is what counts as knowledge organised; how is what counts as knowledge transmitted; how is…

  9. Revisiting Jack Goody to Rethink Determinisms in Literacy Studies

    Science.gov (United States)

    Collin, Ross

    2013-01-01

    This article revisits Goody's arguments about literacy's influence on social arrangements, culture, cognition, economics, and other domains of existence. Whereas some of his arguments tend toward technological determinism (i.e., literacy causes change in the world), other of his arguments construe literacy as a force that shapes and is shaped by…

  10. Revisiting the Role of Communication in Adolescent Intimate Partner Violence

    Science.gov (United States)

    Messinger, Adam M.; Rickert, Vaughn I.; Fry, Deborah A.; Lessel, Harriet; Davidson, Leslie L.

    2012-01-01

    A growing literature suggests that communication strategies can promote or inhibit intimate partner violence (IPV). Research on communication is still needed on a group ripe for early IPV intervention: high school-aged adolescents. This article revisits our previous analyses of young female reproductive clinic patients (Messinger, Davidson, &…

  11. Revisiting the Gramscian Legacy on Counter-Hegemony, the ...

    African Journals Online (AJOL)

    This article seeks to revisit Gramsci‟s legacy on counter-hegemony, the subaltern and affectivity, by focusing on the implications of his cutting-edge position on the role of subaltern feelings in the formation of an „emotional pedagogy‟ of activism in the context of higher education. Three insights follow from this analysis.

  12. The Legacy of Daantjie Oosthuizen: Revisiting the Liberal Defence ...

    African Journals Online (AJOL)

    canberry

    The Legacy of Daantjie Oosthuizen: Revisiting the Liberal Defence of. Academic Freedom. André du Toit. De part ment of Po lit i cal Studies. Uni ver sity of Cape Town. Cape Town. Intro duction. The classic formu la tions of the liberal notion of academic freedom in the South. African context date from the period of the late ...

  13. A different kind of reformation : Revisiting the Lynn White Thesis

    NARCIS (Netherlands)

    Jedan, Christoph

    2017-01-01

    This commentary revisits Lynn White’s article, ‘The Historical Roots of Our Ecologic Crisis’ (1967), and questions the assumption that there is a unified ‘Lynn White thesis’. Instead, it proposes a complex narrative in which four key elements can be identified: (1) the long history of human impact

  14. Coagulation revisited : Special focus on Prothrombotic states and ...

    African Journals Online (AJOL)

    Adele

    clot . We now have greater insight than ever before on the. Coagulation revisited : Special focus on. Prothrombotic states and anticoagulation. S Mayet degradation of clot and how the different mediators like thrombin , antithrombin and protein C and S act on the cascade. This review aims to provide an overview of the “new”.

  15. Revisiting the teaching of specific language structures in the ...

    African Journals Online (AJOL)

    Revisiting the teaching of specific language structures in the nominal group and the verbal group in English in a second language learning environment. ... nominal group and the verbal group results in the acquisition of knowledge of how ideas can be accessed in the reading of texts, specific reference to academic prose.

  16. Lemba origins revisited: Tracing the ancestry of Y chromosomes in ...

    African Journals Online (AJOL)

    Background. Previous historical, anthropological and genetic data provided overwhelming support for the Semitic origins of the Lemba, a Bantu-speaking people in southern Africa. Objective. To revisit the question concerning genetic affinities between the Lemba and Jews. Methods. Y-chromosome variation was examined ...

  17. Jesus and the law revisited | Loader | HTS Teologiese Studies ...

    African Journals Online (AJOL)

    This article revisited the issue of Jesus' attitude towards the Torah on the basis of a critical discussion of the most recent extensive treatment of the theme by Meier in his A marginal Jew: Rethinking the historical Jesus: Volume four: Law and love (2009). It engaged Meier's contribution in the light of contemporary research, ...

  18. Coccolithophores in Polar Waters: Papposphaera arctica HET and HOL revisited

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Heldal, Mikal; Østergaard, Jette B.

    2016-01-01

    It has been generally accepted based on the finding of combination coccospheres in field samples that Turrisphaera arctica and Papposphaera sarion are alternate life-cycle phases of a single species. However, while recently revisiting P. sarion it became evident that the Turrisphaera phase of thi...

  19. "An analysis of the classical Doppler Effect"[1] revisited

    OpenAIRE

    Rothenstein, Bernhard; Nafornita, Corina

    2004-01-01

    After having shown that the formula which describes the Doppler effect in the general case holds only in the case of the "very high" frequency assumption, we derive free of assumptions Doppler formulas for two scenarios presented in the revisited paper.

  20. Thorbecke Revisited : The Role of Doctrinaire Liberalism in Dutch Politics

    NARCIS (Netherlands)

    Drentje, Jan

    2011-01-01

    Thorbecke Revisited: The Role of Doctrinaire Liberalism in Dutch Politics In the political history of the nineteenth century Thorbecke played a crucial role. As the architect of the 1848 liberal constitutional reform he led three cabinets. In many ways he dominated the political discourse during the

  1. Frederick Herzberg\\'s motivation-hygiene theory revisited: The ...

    African Journals Online (AJOL)

    Frederick Herzberg\\'s motivation-hygiene theory revisited: The concept and its applicability to clergy (A study of fulltime stipendiary clergy of the global ... of Wood's (1973) “Faculty Job Satisfaction/Dissatisfaction Scale” was used to measure the satisfaction of clergy relative to Herzberg's satisfier and dissatisfier factors.

  2. Faraday effect revisited: sum rules and convergence issues

    DEFF Research Database (Denmark)

    Cornean, Horia; Nenciu, Gheorghe

    2010-01-01

    This is the third paper of a series revisiting the Faraday effect. The question of the absolute convergence of the sums over the band indices entering the Verdet constant is considered. In general, sum rules and traces per unit volume play an important role in solid-state physics, and they give...

  3. Sleeping sickness in Uganda: revisiting current and historical ...

    African Journals Online (AJOL)

    Sleeping sickness in Uganda: revisiting current and historical distributions. L Berrang-Ford, M Odiit, F Maiso, D Waltner-Toews, J McDermott. Abstract. Background: Sleeping sickness is a parasitic, vector-borne disease, carried by the tsetse fly and prevalent in sub-Saharan Africa. The disease continues to pose a public ...

  4. Living the myth: Revisiting Okigbo's art and commitment

    African Journals Online (AJOL)

    Living the myth: Revisiting Okigbo's art and commitment. This is a study of the nature and sources of the persona's quest in Christopher Okigbo's poetry. The protagonist in Okigbo's writing explores the fluid borders between aesthetic and spiritual states, with language and social action as instruments of the self's aspiration ...

  5. The military glider revisited | Heitman | Scientia Militaria: South ...

    African Journals Online (AJOL)

    Scientia Militaria: South African Journal of Military Studies. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 12, No 3 (1982) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. The military glider revisited.

  6. Revisiting Public Health Challenges in the New Millennium | Anish ...

    African Journals Online (AJOL)

    The current article briefly narrates the burden and complexities of challenges faced by the present global health. Revisiting the concept of PHC and reaffirming our solidarity to this philosophy is the need of this hour. Keywords: Asia, Development goals, Millennium, Public health, Public health challenges, Primary healthcare ...

  7. Revisited sunspot numbers and prediction of solar cycle 25

    Science.gov (United States)

    Pishkalo, M.

    2016-06-01

    Parameteres of solar cycles are found usind revisited sunspot numbers in 2015. Correlations between cycle parameters were studied. Solar cycle 25 was predicted using regression equations obtained. I was predicted that minimum and maximum of the cycle (8.3 and 166.7) will occur in May of 2020 and November 2024 to February 2025 respectively.49

  8. Threshold Concepts and Student Engagement: Revisiting Pedagogical Content Knowledge

    Science.gov (United States)

    Zepke, Nick

    2013-01-01

    This article revisits the notion that to facilitate quality learning requires teachers in higher education to have pedagogical content knowledge. It constructs pedagogical content knowledge as a teaching and learning space that brings content and pedagogy together. On the content knowledge side, it suggests that threshold concepts, akin to a…

  9. Revisiting the relevance of economic theory to hotel revenue ...

    African Journals Online (AJOL)

    Revisiting the relevance of economic theory to hotel revenue management education and practice in the era of Big Data. ... Research in Hospitality Management ... This paper explores the role of economics in hospitality education and industry practice, with a particular focus on revenue management, and puts forward an ...

  10. Assesment of mucoadhesion using small deformation rheology revisited

    DEFF Research Database (Denmark)

    Harloff-Helleberg, Stine; Vissing, Karina Juul; Nielsen, Hanne Mørck

    2017-01-01

    This work revisits the commonly used approach to assess mucoadhesion in drug delivery by small deformation rheology. The results show that biosimilar mucus serves as a more predictive mucus model system when compared to mucin suspensions. Data is fitted including error propagation, different from...

  11. Literary Origins of the Term "School Psychologist" Revisited

    Science.gov (United States)

    Fagan, Thomas K.

    2005-01-01

    Previous research on the literary origins of the term "school psychologist" is revisited, and conclusions are revised in light of new evidence. It appears that the origin of the term in the American literature occurred as early as 1898 in an article by Hugo Munsterberg, predating the usage by Wilhelm Stern in 1911. The early references to the…

  12. Revisiting the issue of elite capture in participatory initiatives

    DEFF Research Database (Denmark)

    Lund, Jens Friis; Saito-Jensen, Moeko

    2013-01-01

    Based on case studies of two communities implementing participatory forestry in Tanzania and India, we revisit the issue of elite capture of participatory initiatives. Our cases illustrate how initial elite capture of the participatory initiatives is circumvented over time through various forms...

  13. Revisiting the Continua of Biliteracy: International and Critical Perspectives.

    Science.gov (United States)

    Hornberger, Nancy H.; Skilton-Sylvester, Ellen

    2000-01-01

    The continua model of biliteracy offers a framework to situate research, teaching, and language planning in linguistically diverse settings. The continua model is revisited from the perspective of international cases of educational policy and practice in linguistically diverse settings, and from a critical perspective that seeks to make explicit…

  14. Revisiting deforestation in Africa (1990–2010): One more lost ...

    African Journals Online (AJOL)

    This spotlight revisits the dynamics and prognosis outlined in the late 1980's published in Déforestation en Afrique. This book on deforestation in Africa utilized available statistical data from the 1980's and was a pioneering self - styled attempt to provide a holistic viewpoint of the ongoing trends pertaining to deforestation in ...

  15. Rereading Albert B. Lord's The Singer of Tales . Revisiting the ...

    African Journals Online (AJOL)

    Access to a fresh set of video-recordings of Sesotho praise-poetry made in the year 2000 enabled the author to revisit his adaptation of Albert Lord's definition of the formula as a dynamic compositional device that the oral poet utilizes during delivery. The basic adaptation made in 1983 pertains to heroic praises (dithoko tsa ...

  16. Revisiting the importance of childhood activity | van Rensburg ...

    African Journals Online (AJOL)

    This article revisits the risks of physical inactivity in childhood and provides the latest recommendations for exercise prescription in the paediatric population. Inactive children have a higher risk of developing chronic diseases, such as obesity, type 2 diabetes, high blood cholesterol and hypertension. Other undesirable ...

  17. Stuck Schools Revisited: Beneath the Averages. K-12 Policy

    Science.gov (United States)

    Ushomirsky, Natasha

    2011-01-01

    "Stuck Schools Revisited: Beneath the Averages" shows why a national focus on turning around the lowest performing schools, while needed, is not enough to raise achievement and close gaps. The report analyzes student achievement data from Maryland and Indiana, which reflect the outcomes seen in other states. The results confirm a…

  18. Environmental Education and Politics: Snakes and Ladders Revisited

    Science.gov (United States)

    Chapman, David

    2004-01-01

    This paper revisits the history of environmental education in Australia in the 1970s and 1980s and draws parallels between these and current events in four countries, including Australia. It is argued that little has changed and that few environmental educators confront the inherently political nature of their work. It is concluded that…

  19. Downlink Transmission of Short Packets: Framing and Control Information Revisited

    DEFF Research Database (Denmark)

    Trillingsgaard, Kasper Fløe; Popovski, Petar

    2017-01-01

    Cellular wireless systems rely on frame-based transmissions. The frame design is conventionally based on heuristics, consisting of a frame header and a data part. The frame header contains control information that provides pointers to the messages within the data part. In this paper, we revisit t...

  20. Revisiting Constructivist Teaching Methods in Ontario Colleges Preparing for Accreditation

    Science.gov (United States)

    Schultz, Rachel A.

    2015-01-01

    At the time of writing, the first community colleges in Ontario were preparing for transition to an accreditation model from an audit system. This paper revisits constructivist literature, arguing that a more pragmatic definition of constructivism effectively blends positivist and interactionist philosophies to achieve both student centred…

  1. Bohr’s ‘Light and Life’ revisited

    Science.gov (United States)

    Nussenzveig, H. M.

    2015-11-01

    I revisit Niels Bohr’s famous 1932 ‘Light and Life’ lecture, confronting it with current knowledge. Topics covered include: life origin and evolution, quantum mechanics and life, brain and mind, consciousness and free will, and light as a tool for biology, with special emphasis on optical tweezers and their contributions to biophysics. Specialized knowledge of biology is not assumed.

  2. Local structure and morphological evolution of ZnTPP molecules grown on Fe(001)-p(1 × 1)O studied by STM and NEXAFS

    Science.gov (United States)

    Picone, Andrea; Giannotti, Dario; Brambilla, Alberto; Bussetti, Gianlorenzo; Calloni, Alberto; Yivlialin, Rossella; Finazzi, Marco; Duò, Lamberto; Ciccacci, Franco; Goldoni, Andrea; Verdini, Alberto; Floreano, Luca

    2018-03-01

    When used as substrates, thin metal-oxide (MO) layers can perturb the physical and chemical properties of molecules in contact with the surface. To study the molecule-MO layer interaction, we focused our investigation on a prototypical interface, namely zinc tetraphenylporphyrin (ZnTPP) film on Fe(001)-p(1 × 1)O. In a previous study, we found that no significant change of the electronic structure takes place at the monolayer (ML) coverage either in the core level photoemission spectra or in the highest occupied molecular orbitals (HOMOs). However, molecules showed the occurrence of a commensurate (5 × 5) diffraction pattern that indicates a certain degree of interaction with the substrate. In order to better understand the effective molecule/metal decoupling operated by the FeO layer, we performed a combined investigation based on a scanning tunneling microscopy (STM) study of the self-assembled ZnTPP molecular layer and on a near edge X-ray absorption fine structure spectroscopy (NEXAFS). Molecules are found to lie almost parallel to the substrate, even if the central macrocycle displays a characteristic small saddle-like distortion (symmetry from D4h to D2h drives the azimuthal orientation with respect to the substrate and determines the co-existence of four equivalent (5 × 5) ZnTPP domains, following the substrate four-fold symmetry. The comparison with films of increasing thickness shows that, beyond the second layer, the molecules gradually tilt-off the surface (by at least 40°) ordering into 3D islands. The NEXAFS resonances of the lowest unoccupied orbitals (LUMOs) do not display significant changes from the monolayer to the multilayer thickness range, apart from minor modification of the LUMOs relative intensity. The latter variation may be associated with the change of spatial spread of the molecular orbitals in the contact layer due to the saddle-like distortion.

  3. N = 2 S-duality revisited

    Science.gov (United States)

    Buican, Matthew; Laczko, Zoltan; Nishinaka, Takahiro

    2017-09-01

    Using the chiral algebra bootstrap, we revisit the simplest Argyres-Douglas (AD) generalization of Argyres-Seiberg S-duality. We argue that the exotic AD superconformal field theory (SCFT), T_{3,3/2} , emerging in this duality splits into a free piece and an interacting piece, T_X , even though this factorization seems invisible in the Seiberg-Witten (SW) curve derived from the corresponding M5-brane construction. Without a Lagrangian, an associated topological field theory, a BPS spectrum, or even an SW curve, we nonetheless obtain exact information about T_X by bootstrapping its chiral algebra, {}_X(T_X) , and finding the corresponding vacuum character in terms of Affine Kac-Moody characters. By a standard 4D/2D correspondence, this result gives us the Schur index for T_X and, by studying this quantity in the limit of small S 1, we make contact with a proposed S 1 reduction. Along the way, we discuss various properties of T_X : as an N = 1 theory, it has flavor symmetry SU(3) × SU(2) × U(1), the central charge of {}_X(T_X) matches the central charge of the bc ghosts in bosonic string theory, and its global SU(2) symmetry has a Witten anomaly. This anomaly does not prevent us from building conformal manifolds out of arbitrary numbers of T_X theories (giving us a surprisingly close AD relative of Gaiotto's T N theories), but it does lead to some open questions in the context of the chiral algebra/4D N =2SCFT correspondence.

  4. Solar system anomalies: Revisiting Hubble's law

    Science.gov (United States)

    Plamondon, R.

    2017-12-01

    This paper investigates the impact of a new metric recently published [R. Plamondon and C. Ouellet-Plamondon, in On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics, and Relativistic Field Theories, edited by K. Rosquist, R. T. Jantzen, and R. Ruffini (World Scientific, Singapore, 2015), p. 1301] for studying the space-time geometry of a static symmetric massive object. This metric depends on a complementary error function (erfc) potential that characterizes the emergent gravitation field predicted by the model. This results in two types of deviations as compared to computations made on the basis of a Newtonian potential: a constant and a radial outcome. One key feature of the metric is that it postulates the existence of an intrinsic physical constant σ , the massive object-specific proper length that scales measurements in its surroundings. Although σ must be evaluated experimentally, we use a heuristic to estimate its value and point out some latent relationships between the Hubble constant, the secular increase in the astronomical unit, and the Pioneers delay. Indeed, highlighting the systematic errors that emerge when the effect of σ is neglected, one can link the Hubble constant H 0 to σ Sun and the secular increase V AU to σ Earth . The accuracy of the resulting numerical predictions, H 0 = 74 . 42 ( 0 . 02 ) ( km / s ) / Mpc and V AU ≅ 7.8 cm yr-1 , calls for more investigations of this new metric by specific experts. Moreover, we investigate the expected impacts of the new metric on the flyby anomalies, and we revisit the Pioneers delay. It is shown that both phenomena could be partly taken into account within the context of this unifying paradigm, with quite accurate numerical predictions. A correction for the osculating asymptotic velocity at the perigee of the order of 10 mm/s and an inward radial acceleration of 8 . 34 × 10 - 10 m / s 2 affecting the Pioneer ! space crafts could be explained by this new model.

  5. Systematic imaging review: Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Aparna Katdare

    2015-01-01

    Full Text Available Multiple sclerosis (MS is a chronic, inflammatory disease of the central nervous system characterised by immune-mediated demyelination, and is a leading cause of neurological disability worldwide. It has a wide spectrum of clinical presentations which overlap with other neurological conditions many times. Further, the radiological array of findings in MS can also be confused for multiple other conditions, leading to the need to look for the more typical findings, and interpret these in close conjunction with the clinical picture including temporal evolution. This review aims to revisit the MRI findings in MS, including recent innovations in imaging, and to help distinguish MS from its mimics.

  6. Two types of representation in visual memory: evidence from the effects of stimulus contrast on image combination.

    Science.gov (United States)

    Hitch, G J; Brandimonte, M A; Walker, P

    1995-03-01

    An imagery task was used to explore the distinction between visual memory representations that preserve surface features and more abstract descriptions. Subjects were shown two line drawings and were then asked to combine a visual image of each drawing in order to identify a novel figure. The main experimental manipulation concerned the contrast in which each drawing was shown, which was either normal or reversed. Experiment 1 showed that image combination was more efficient when the contrasts of the two drawings were congruent with each other, but only when the imagery task was performed under conditions emphasizing short-term memory (STM). There was no effect of congruity when one of the images was generated from long-term memory (LTM). These results are consistent with the idea that the surface characteristics of a stimulus are preserved in visual STM, but a more abstract description is stored in visual LTM. In Experiment 2 we explored the influence of verbal recoding on performance of the imagery task by requiring subjects to suppress articulation. Under LTM conditions, performance of the imagery task was improved by suppression and became sensitive to contrast congruity. Under STM conditions, imagery was unaffected by suppression. Overall, these results support the distinction between surface and abstract descriptions in visual memory. However, they suggest that this distinction does not map onto that between STM and LTM in any simple way. It is suggested that short-term visual memory maintains surface descriptions and long-term visual memory preserves both surface and abstract descriptions. Verbal coding of visual stimuli appears to encourage the use of abstract visual descriptions.

  7. IMAGES, IMAGES, IMAGES

    Energy Technology Data Exchange (ETDEWEB)

    Marcus, A.

    1980-07-01

    The role of images of information (charts, diagrams, maps, and symbols) for effective presentation of facts and concepts is expanding dramatically because of advances in computer graphics technology, increasingly hetero-lingual, hetero-cultural world target populations of information providers, the urgent need to convey more efficiently vast amounts of information, the broadening population of (non-expert) computer users, the decrease of available time for reading texts and for decision making, and the general level of literacy. A coalition of visual performance experts, human engineering specialists, computer scientists, and graphic designers/artists is required to resolve human factors aspects of images of information. The need for, nature of, and benefits of interdisciplinary effort are discussed. The results of an interdisciplinary collaboration are demonstrated in a product for visualizing complex information about global energy interdependence. An invited panel will respond to the presentation.

  8. The role of brand destination experience in determining revisit intention

    DEFF Research Database (Denmark)

    Mattsson, Jan; Barnes, Stuart; Sørensen, Flemming

    experience, which provides a more holistic and unified view of the brand destination. The research uses a logistic regression model to determine the role of satisfaction and brand experience in determining revisit intentions. The study also examines differences among subgroups and four brand experience sub......-constructs. The findings suggest that brand experience is an important determinant of revisit intentions, but that there is variation among respondent groups. The paper rounds off with conclusions and implications for research and practice.......Destination branding has developed considerably as a topic area in the last decade with numerous conceptualizations focusing on different aspects of the brand. However, a unified view has not yet emerged. This paper examines destination branding via a new conceptualization, brand destination...

  9. The significance test controversy revisited the fiducial Bayesian alternative

    CERN Document Server

    Lecoutre, Bruno

    2014-01-01

    The purpose of this book is not only to revisit the “significance test controversy,”but also to provide a conceptually sounder alternative. As such, it presents a Bayesian framework for a new approach to analyzing and interpreting experimental data. It also prepares students and researchers for reporting on experimental results. Normative aspects: The main views of statistical tests are revisited and the philosophies of Fisher, Neyman-Pearson and Jeffrey are discussed in detail. Descriptive aspects: The misuses of Null Hypothesis Significance Tests are reconsidered in light of Jeffreys’ Bayesian conceptions concerning the role of statistical inference in experimental investigations. Prescriptive aspects: The current effect size and confidence interval reporting practices are presented and seriously questioned. Methodological aspects are carefully discussed and fiducial Bayesian methods are proposed as a more suitable alternative for reporting on experimental results. In closing, basic routine procedures...

  10. Submolecular resolution in scanning probe images of Sn-phthalocyanines on Cu(1 0 0) using metal tips

    Science.gov (United States)

    Buchmann, Kristof; Hauptmann, Nadine; Foster, Adam S.; Berndt, Richard

    2017-10-01

    Single Sn-phthalocyanine (SnPc) molecules adsorb on Cu(1 0 0) with the Sn ion above (Sn-up) or below (Sn-down) the molecular plane. Here we use a combination of atomic force microscopy (AFM), scanning tunnelling microscopy (STM) and first principles calculations to understand the adsorption configuration and origin of observed contrast of molecules in the Sn-down state. AFM with metallic tips images the pyrrole nitrogen atoms in these molecules as attractive features while STM reveals a chirality of the electronic structure of the molecules close to the Fermi level E_F, which is not observed in AFM. Using density functional theory calculations, the origin of the submolecular contrast is analysed and, while the electrostatic forces turn out to be negligible, the van der Waals interaction between the phenyl rings of SnPc and the substrate deform the molecule, push the pyrrole nitrogen atoms away from the substrate and thus induce the observed submolecular contrast. Simulated STM images reproduce the chirality of the electronic structure near E_F.

  11. Complexity Measure Revisited: A New Algorithm for Classifying Cardiac Arrhythmias

    Science.gov (United States)

    2001-10-25

    Complexity Measure Revisited: A New Algorithm for Classifying Cardiac Arrhythmias Contract Number Grant Number Program Element Number Author(s) Project...to set-up the acquisition and processing characteristics of ECG signal. REFERENCES [1] Special Issue on Electrical Therapy of Cardiac Arrhythmias , 3URFHHGLQJV...JM Jenkins, LA DiCarlo. “Detection and Identification of Cardiac Arrhythmias Using an adaptive, Linear-Predictive Filter”, ,((( &RPSXWHUV LQ

  12. Quark matter revisited with non-extensive MIT bag model

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Pedro H.G.; Nunes da Silva, Tiago; Menezes, Debora P. [Universidade Federal de Santa Catarina, Departamento de Fisica, CFM, Florianopolis (Brazil); Deppman, Airton [Instituto de Fisica da Universidade de Sao Paulo, Sao Paulo (Brazil)

    2017-10-15

    In this work we revisit the MIT bag model to describe quark matter within both the usual Fermi-Dirac and the Tsallis statistics. We verify the effects of the non-additivity of the latter by analysing two different pictures: the first order phase transition of the QCD phase diagram and stellar matter properties. While the QCD phase diagram is visually affected by the Tsallis statistics, the resulting effects on quark star macroscopic properties are barely noticed. (orig.)

  13. Serotype-specific mortality from invasive Streptococcus pneumoniae disease revisited

    DEFF Research Database (Denmark)

    Martens, Pernille; Worm, Signe Westring; Lundgren, Bettina

    2004-01-01

    Serotype-specific mortality from invasive Streptococcus pneumoniae disease revisited.Martens P, Worm SW, Lundgren B, Konradsen HB, Benfield T. Department of Infectious Diseases 144, Hvidovre University Hospital, DK-2650 Hvidovre, Denmark. pernillemartens@yahoo.com BACKGROUND: Invasive infection...... with Streptococcus pneumoniae (pneumococci) causes significant morbidity and mortality. Case series and experimental data have shown that the capsular serotype is involved in the pathogenesis and a determinant of disease outcome. METHODS: Retrospective review of 464 cases of invasive disease among adults diagnosed...

  14. Deja vu: The Unified Command Plan of the Future Revisited

    Science.gov (United States)

    2011-05-19

    Approved for Public Release; Distribution is Unlimited Déjà vu : The Unified Command Plan of the Future Revisited A Monograph by Lieutenant...DD-MM-YYYY) 19-05-2011 2. REPORT TYPE Monograph 3. DATES COVERED (From - To) JUL 2010 – MAY 2011 4. TITLE AND SUBTITLE Déjà vu : The Unified...i SCHOOL OF ADVANCED MILITARY STUDIES MONOGRAPH APPROVAL Lieutenant Colonel Edward Francis Martignetti Title of Monograph: Déjà vu : The Unified

  15. Brand extensions: brand concept congruency and feedback effects revisited

    OpenAIRE

    Thorbjørnsen, Helge

    2005-01-01

    -This is the author's version of the article:"Brand extensions: brand concept congruency and feedback effects revisited" Journal of Product & Brand Management, Vol. 14 Iss: 4, pp.250 - 257, Abstract Purpose – The aim of this research is to examine the effects of congruent and incongruent brand concept extensions on consumer attitudes towards the extended product and feedback effects on the parent brand. Moreover, brand familiarity is proposed as an important mo...

  16. Revisiting the Response Mechanism of Polymeric Membrane Based Heparin Electrodes

    OpenAIRE

    Bell, Andrea K.; Höfler, Lajos; Meyerhoff, Mark E.

    2011-01-01

    Potentiometric membrane electrodes that respond to heparin and other polyanions were introduced in the early 1990s. Herein, the mechanism of polymer membrane electrode type heparin sensors is revisited. The extraction/diffusion of heparin is studied via both potentiometric and impedance spectroscopic techniques using a pre-fractionated heparin preparation that contains polyanionic species > 10000 Daltons. The reversal in EMF response using this heparin preparation indicates diffusion of highe...

  17. Dispute Resolution and Technology: Revisiting the Justification of Conflict Management

    OpenAIRE

    Koulu, Riikka

    2016-01-01

    This study, Dispute Resolution and Technology: Revisiting the Justification of Conflict Management, belongs to the fields of procedural law, legal theory and law and technology studies. In this study the changes in dispute resolution caused by technology are evaluated. The overarching research question of this study is how does implementing technology to dispute resolution challenge the justification of law as a legitimised mode of violence? Before answering such an abstract research question...

  18. Place attachment and social legitimacy: Revisiting the sustainable entrepreneurship journey

    OpenAIRE

    Kibler, Ewald; Fink, Matthias; Lang, R.; Munoz, P.

    2015-01-01

    This paper revisits the sustainable entrepreneurship journey by introducing a ‘place- based’ sustainable venture path model. We suggest that distinguishing between emo- tional (‘caring about the place’) and instrumental (‘using the place’) place attachment of sustainable entrepreneurs deepens our understanding of how place-based challenges of sustainable venture legitimacy are managed over time. We conclude with avenues for future sustainable entrepreneurship research.

  19. Indoor air and human health revisited: A recent IAQ symposium

    Energy Technology Data Exchange (ETDEWEB)

    Gammage, R.B.

    1994-12-31

    Indoor Air and Human Health Revisited was a speciality symposium examining the scientific underpinnings of sensory and sensitivity effects, allergy and respiratory disease, neurotoxicity and cancer. An organizing committee selected four persons to chain the sessions and invite experts to give state-of-the-art presentations that will be published as a book. A summary of the presentations is made and some critical issues identified.

  20. Digital Subtraction Radiography - A Technique Revisited

    Directory of Open Access Journals (Sweden)

    Anshul Mehra

    2007-01-01

    Full Text Available Digital imaging has changed the scenario of medical and dental imaging as it has been able to address many limitations associated with traditional film based radiograph. However, subtle changes on the image are still difficult to appreciate by the human eye because the changes are buried in a background of normal anatomic structures, and are not clearly evident. Digital subtraction radiography is one of the image enhancing technique which addresses this problem and has found its use in various fields of dentistry in the recent past. However, there is lack of review in the literature regarding this widely used technique. The purpose of this article is to present an overview of this technique and its uses in various fields of dentistry.

  1. Thinking beyond the block: block matching for copy-move forgery detection revisited

    Science.gov (United States)

    Kirchner, Matthias; Schöttle, Pascal; Riess, Christian

    2015-03-01

    Detection of copy{move forgeries is one of the most actively researched topics in image forensics. It has been shown that so-called block-based methods give the highest pixel-wise accuracy for detecting copy{move forgeries. However, matching of block-based features can be computationally extremely demanding. Hence, the current predominant line of thought is that block-based algorithms are too slow to be applicable in practice. In this paper, we revisit the matching stage of block-based copy{move forgery detection methods. We propose an efficient approach for finding duplicate patterns of a given size in integer-valued input data. By design, we focus on the spatial relation of potentially duplicated elements. This allows us to locate copy{move forgeries via bit-wise operations, without expensive block comparisons in the feature space. Experimental investigation of different matching strategies shows that the proposed method has its benefits. However, on a broader scale, our experiments demonstrate that the performance of matching by lexicographic sorting might have been underestimated in previous work, despite its remarkable speed benefit on large images. In fact, in a practical setting, where accuracy and computational efficiency have to be balanced, lexicographic sorting may be considered the method of choice.

  2. Galactic rings revisited - I. CVRHS classifications of 3962 ringed galaxies from the Galaxy Zoo 2 Database

    Science.gov (United States)

    Buta, Ronald J.

    2017-11-01

    Rings are important and characteristic features of disc-shaped galaxies. This paper is the first in a series that re-visits galactic rings with the goals of further understanding the nature of the features and for examining their role in the secular evolution of galaxy structure. The series begins with a new sample of 3962 galaxies drawn from the Galaxy Zoo 2 citizen science data base, selected because zoo volunteers recognized a ring-shaped pattern in the morphology as seen in Sloan Digital Sky Survey colour images. The galaxies are classified within the framework of the Comprehensive de Vaucouleurs revised Hubble-Sandage system. It is found that zoo volunteers cued on the same kinds of ring-like features that were recognized in the 1995 Catalogue of Southern Ringed Galaxies. This paper presents the full catalogue of morphological classifications, comparisons with other sources of classifications and some histograms designed mainly to highlight the content of the catalogue. The advantages of the sample are its large size and the generally good quality of the images; the main disadvantage is the low physical resolution that limits the detectability of linearly small rings such as nuclear rings. The catalogue includes mainly inner and outer disc rings and lenses. Cataclysmic (`encounter-driven') rings (such as ring and polar ring galaxies) are recognized in less than 1 per cent of the sample.

  3. Reverse redistribution. Revisited with myocardial contrast echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Wonsick; Kwan, Jun; Kim, Sungeun [Inha Univ., Inchon (Korea, Republic of). Hospital

    2000-02-01

    The aim of this study is to better understand the pattern and nature of reverse redistribution (RR) in myocardial perfusion imaging. In 20 consecutive acute myocardial infarction (MI) patients, frequency of RR was correlated with that of subendocardial MI that was detected by myocardial contrast echocardiography (MCE). RR was judged to be present when there was more than one grade of worsening in perfusion on 24 hr delayed images compared with the initial rest images. MCE evaluated no opacification in the subendocardial myocardium to suggest subendocardial MI. Kendall's nonparametric correlation coefficiency was calculated. Concordant cases were 15 of 20 (75%) and correlation was statistically significant (p=0.0285). Our results suggested that RR was correlated with MCE-detected nontransmural MI. (author)

  4. Revisiting Metaphors for Education: A Student's Perspective

    Science.gov (United States)

    Nikitina, Larisa; Furuoka, Fumitaka

    2011-01-01

    This study examines metaphors about learning produced by a group of eighteen students at a big public university in Malaysia. The learner perspective is placed within a wider discourse on education in order to explore whether the images employed by the learners to describe their learning reflect the dominant conception of education as…

  5. Circular revisit orbits design for responsive mission over a single target

    Science.gov (United States)

    Li, Taibo; Xiang, Junhua; Wang, Zhaokui; Zhang, Yulin

    2016-10-01

    The responsive orbits play a key role in addressing the mission of Operationally Responsive Space (ORS) because of their capabilities. These capabilities are usually focused on supporting specific targets as opposed to providing global coverage. One subtype of responsive orbits is repeat coverage orbit which is nearly circular in most remote sensing applications. This paper deals with a special kind of repeating ground track orbit, referred to as circular revisit orbit. Different from traditional repeat coverage orbits, a satellite on circular revisit orbit can visit a target site at both the ascending and descending stages in one revisit cycle. This typology of trajectory allows a halving of the traditional revisit time and does a favor to get useful information for responsive applications. However the previous reported numerical methods in some references often cost lots of computation or fail to obtain such orbits. To overcome this difficulty, an analytical method to determine the existence conditions of the solutions to revisit orbits is presented in this paper. To this end, the mathematical model of circular revisit orbit is established under the central gravity model and the J2 perturbation. A constraint function of the circular revisit orbit is introduced, and the monotonicity of that function has been studied. The existent conditions and the number of such orbits are naturally worked out. Taking the launch cost into consideration, optimal design model of circular revisit orbit is established to achieve a best orbit which visits a target twice a day in the morning and in the afternoon respectively for several days. The result shows that it is effective to apply circular revisit orbits in responsive application such as reconnoiter of natural disaster.

  6. A practical method of predicting client revisit intention in a hospital setting.

    Science.gov (United States)

    Lee, Kyun Jick

    2005-01-01

    Data mining (DM) models are an alternative to traditional statistical methods for examining whether higher customer satisfaction leads to higher revisit intention. This study used a total of 906 outpatients' satisfaction data collected from a nationwide survey interviews conducted by professional interviewers on a face-to-face basis in South Korea, 1998. Analyses showed that the relationship between overall satisfaction with hospital services and outpatients' revisit intention, along with word-of-mouth recommendation as intermediate variables, developed into a nonlinear relationship. The five strongest predictors of revisit intention were overall satisfaction, intention to recommend to others, awareness of hospital promotion, satisfaction with physician's kindness, and satisfaction with treatment level.

  7. Revisiting Ectopic Pregnancy: A Pictorial Essay

    Directory of Open Access Journals (Sweden)

    Artemis Petrides

    2014-01-01

    Full Text Available Ectopic pregnancies occur in approximately 1.4% of all pregnancies and account for 15% of pregnancy-related deaths. Considering the high degree of mortality, recognizing an ectopic pregnancy is important. Signs and symptoms of an ectopic pregnancy are nonspecific and include pain, vaginal bleeding, and an adnexal mass. Therefore, imaging can play a critical role in diagnosis. There are different types of ectopic pregnancies, which are tubal, cornual, cesarean scar, cervical, heterotopic, abdominal, and ovarian. Initial imaging evaluation of pregnant patients with pelvic symptoms is by ultrasonography, transabdominal, transvaginal or both. We review the sonographic appearance of different types of ectopic pregnancies that will aid in accurate and prompt diagnosis.

  8. Emergency department revisits for patients with kidney stones in California.

    Science.gov (United States)

    Scales, Charles D; Lin, Li; Saigal, Christopher S; Bennett, Carol J; Ponce, Ninez A; Mangione, Carol M; Litwin, Mark S

    2015-04-01

    Kidney stones affect nearly one in 11 persons in the United States, and among those experiencing symptoms, emergency care is common. In this population, little is known about the incidence of and factors associated with repeat emergency department (ED) visits. The objective was to identify associations between potentially mutable factors and the risk of an ED revisit for patients with kidney stones in a large, all-payer cohort. This was a retrospective cohort study of all patients in California initially treated and released from EDs for kidney stones between February 2008 and November 2009. A multivariable regression model was created to identify associations between patient-level characteristics, area health care resources, processes of care, and the risk of repeat ED visits. The primary outcome was a second ED visit within 30 days of the initial discharge from emergent care. Among 128,564 patients discharged from emergent care, 13,684 (11%) had at least one additional emergent visit for treatment of their kidney stone. In these patients, nearly one in three required hospitalization or an urgent temporizing procedure at the second visit. On multivariable analysis, the risk of an ED revisit was associated with insurance status (e.g., Medicaid vs. private insurance; odds ratio [OR] = 1.52, 95% confidence interval [CI] = 1.43 to 1.61; p kidney stones. Access to urologic care and processes of care are associated with lower risk of repeat emergent encounters. Efforts are indicated to identify preventable causes of ED revisits for kidney stone patients and design interventions to reduce the risk of high-cost, high-acuity, repeat care. © 2015 by the Society for Academic Emergency Medicine.

  9. Small-angle scattering theory revisited: Photocurrent and spatial localization

    DEFF Research Database (Denmark)

    Basse, N.P.; Zoletnik, S.; Michelsen, Poul

    2005-01-01

    In this paper theory on collective scattering measurements of electron density fluctuations in fusion plasmas is revisited. We present the first full derivation of the expression for the photocurrent beginning at the basic scattering concepts. Thereafter we derive detailed expressions for the auto......- and crosspower spectra obtained from measurements. These are discussed and simple simulations made to elucidate the physical meaning of the findings. In this context, the known methods of obtaining spatial localization are discussed and appraised. Where actual numbers are applied, we utilize quantities from two...... laser based two-volume collective scattering instrument for spatially localized turbulence measurements,"Rev. Sci. Instrum. 72, 2579-2592 (2001)]....

  10. Revisiting a classic: the Parker-Moffatt problem

    CERN Document Server

    Pezzi, O; Servidio, S; Valentini, F; Vasconez, C L; Yang, Y; Malara, F; Matthaeus, W H; Veltri, P

    2016-01-01

    The interaction of two colliding Alfv\\'en wave packets is here described by means of magnetohydrodynamics (MHD) and hybrid kinetic numerical simulations. The MHD evolution revisits the theoretical insights described by Moffatt, Parker, Kraichnan, Chandrasekhar and Els\\"asser in which the oppositely propagating large amplitude wave packets interact for a finite time, initiating turbulence. However, the extension to include compressive and kinetic effects, while maintaining the gross characteristics of the simpler classic formulation, also reveals intriguing features which go beyond the pure MHD treatment.

  11. Revisiting the Level Scheme of the Proton Emitter 151Lu

    Science.gov (United States)

    Wang, F.; Sun, B. H.; Liu, Z.; Scholey, C.; Ashley, S. F.; Bianco, L.; Cullen, D. M.; Cullen, I. J.; Darby, I. G.; Eeckhaudt, S.; Garnsworthy, A. B.; Gelletly, W.; Gomez-Hornillos, M. B.; Grahn, T.; Greenlees, P. T.; Jenkins, D. G.; Jones, G. A.; Jones, P.; Joss, D. T.; Julin, R.; Juutinen, S.; Kettelhut, S.; Khan, S.; Kishada, A.; Leino, M.; Niikura, M.; Nyman, M.; Page, R. D.; Pakarinen, J.; Pietri, S.; Podolyak, Z.; Rahkila, P.; Rigby, S.; Saren, J.; Seweryniak, D.; Shizuma, T.; Simpson, J.; Sorri, J.; Steer, S.; Thompson, N. J.; Uusitalo, J.; Walker, P. M.; Williams, S.

    An experiment aiming to search for new isomers in the region of proton emitter 151Lu was performed at the Accelerator Laboratory of the University of Jyväskylä (JYFL), by combining the high resolution γ-ray array JUROGAM, gas-filled RITU separator and GREAT detectors with the triggerless total data readout acquisition (TDR) system. In this proceeding, we revisit the level scheme of 151Lu by using the proton-tagging technique. A level scheme consistent with the latest experimental results is obtained, and 3 additional levels are identified at high excitation energies.

  12. A control center design revisited: learning from users’ appropriation

    DEFF Research Database (Denmark)

    Souza da Conceição, Carolina; Cordeiro, Cláudia

    2014-01-01

    This paper aims to present the lessons learned during a control center design project by revisiting another control center from the same company designed two and a half years before by the same project team. In light of the experience with the first project and its analysis, the designers...... and researchers had important feedback already used to suggest changes for the second project. The opportunity to learn from a previous project was unique, but the knowledge gotten out of it shows the importance of having this feedback from project to project instead of just ‘repeating’ previously used design...

  13. Dissipation in relativistic pair-plasma reconnection: revisited

    Science.gov (United States)

    Zenitani, Seiji

    2018-01-01

    Basic properties of relativistic magnetic reconnection in electron–positron pair plasmas are investigated by using a particle-in-cell (PIC) simulation. We first revisit a problem by Hesse and Zenitani (2007 Phys. Plasmas 14 112102), who examined the kinetic Ohm’s law across the X line. We formulate a relativistic Ohm’s law by decomposing the stress–energy tensor. Then, the role of the new term, called the heat-flow inertial term, is examined in the PIC simulation data. We further evaluate the energy balance in the reconnection system. These analyses demonstrate physically transparent ways to diagnose relativistic kinetic data.

  14. REVISITING A CLASSIC: THE PARKER–MOFFATT PROBLEM

    Energy Technology Data Exchange (ETDEWEB)

    Pezzi, O.; Servidio, S.; Valentini, F.; Malara, F.; Veltri, P. [Dipartimento di Fisica, Università della Calabria, 87036 Rende (CS) (Italy); Parashar, T. N.; Yang, Y.; Matthaeus, W. H. [Department of Physics and Astronomy, University of Delaware, DE 19716 (United States); Vásconez, C. L. [Departamento de Física, Escuela Politécnica Nacional, Quito (Ecuador)

    2017-01-10

    The interaction of two colliding Alfvén wave packets is described here by means of magnetohydrodynamics (MHD) and hybrid kinetic numerical simulations. The MHD evolution revisits the theoretical insights described by Moffatt, Parker, Kraichnan, Chandrasekhar, and Elsässer in which the oppositely propagating large-amplitude wave packets interact for a finite time, initiating turbulence. However, the extension to include compressive and kinetic effects, while maintaining the gross characteristics of the simpler classic formulation, also reveals intriguing features that go beyond the pure MHD treatment.

  15. Sampling the equilibrium: the j-walking algorithm revisited

    CERN Document Server

    Rimas, Zilvinas

    2016-01-01

    The j-walking Monte-Carlo algorithm is revisited and updated to study the equilibrium properties of a system exhibiting broken ergodicity. The updated algorithm is tested on the Ising model and applied to the lattice-gas model for sorption in aerogel at low temperatures, when dynamics of the system is critically slowed down. It is demonstrated that the updated j-walking simulations are able to produce equilibrium isotherm which are typically hidden by the hysteresis effect within the standard single-flip simulations.

  16. The Determinants of Visitor’s Revisit Intention: A Lesson from Ijen Car Free Day

    Directory of Open Access Journals (Sweden)

    Cesya Rizkika Parahiyanti

    2015-09-01

    Full Text Available Event industry currently is considered as one of interesting business opportunity in contributing major positive economic impact. Event could be categorized into some activities conducted by an event management or event organizer in the case of achieving some specific outcomes. An event is also recognized as an essential marketing tool in branding of particular destination. It has a powerful function to make a differentiation between one destination and others. This study aims to establish a theoretical event brand equity for which the key components of the brand equity were evaluated from visitor perspective in the tourism context. Brand equity is constructed by four multidimensions which are event brand awareness (EBA, event brand image (EBI, event brand quality (EBQ, and event revisit intention (ERI. By using convenience sampling, 205 visitors of Ijen Car Free Day (ICFD as the event object were used as respondents to obtain the data. This study uses Partial Least Square (PLS to analyze the data both in outer model and inner model measurements. The finding of this study indicate that EBA has positive and significant influence to EBI, EBQ, and ERI. Then, EBI is also proven giving positive and significant influence to EBQ and ERI. In contrary, EBQ does not show significant influence to ERI. The significance movement of this study could be useful measurement in assessing event brand equity management in the future.

  17. The enigma of Gerstmann's syndrome revisited: a telling tale of the vicissitudes of neuropsychology.

    Science.gov (United States)

    Rusconi, Elena; Pinel, Philippe; Dehaene, Stanislas; Kleinschmidt, Andreas

    2010-02-01

    Eighty years ago, the Austrian neurologist Josef Gerstmann observed in a few patients a concomitant impairment in discriminating their own fingers, writing by hand, distinguishing left from right and performing calculations. He claimed that this tetrad of symptoms constituted a syndromal entity, assigned it to a lesion of the dominant parietal lobe and suggested that it was due to damage of a common functional denominator. Ever since, these claims have been debated and an astute synopsis and sceptical discussion was presented 40 years ago by MacDonald Critchley in this journal. Nonetheless, Gerstmann's syndrome has continued to intrigue both clinical neurologists and researchers in neuropsychology, and more frequently than not is described in textbooks as an example of parietal lobe damage. In this review, we revisit the chequered history of this syndrome, which can be seen as a case study of the dialectic evolution of concepts in neuropsychology. In light of several modern era findings of pure cases we conclude that it is legitimate to label the conjunction of symptoms first described by Gerstmann as a 'syndrome', but that it is very unlikely that damage to the same population of cortical neurons should account for all of the four symptoms. Instead, we propose that a pure form of Gerstmann's syndrome might arise from disconnection, via a lesion, to separate but co-localized fibre tracts in the subcortical parietal white matter, a hypothesis for which we have recently provided evidence using combined imaging of functional and structural organization in the healthy brain.

  18. Global Observations of the Wave Field Direction: Revisiting an old idea

    Science.gov (United States)

    Flampouris, Stylianos

    2017-04-01

    The direction of the wave field propagation is one of the most important wave field properties. But in global scale, the directional measurements are mainly satellite products from synthetic aperture radar and therefore have limited spatial and temporal resolution. In the last five years, there is a significant increase of commercial and public constellations of satellites which provide high resolution (up to 0.3m) panchromatic images and/or High Definition videos. This presents an opportunity to accumulate a high volume of wave directional information by revisiting the analysis of sea surface photography. In this paper, data from panchromatic sensors are analyzed using a targeted multistep approach. These steps include, but are not limited to: filtering according to cloud coverage, linear detrending and smoothing in physical space, 2D spectral analysis and filtering to calculate the directional information of the wave field. Landsat-8 datasets from two different locations (mid-Atlantic and Hawaii) are analyzed and validated with in-situ and SAR wave spectra. Additionally, the method is demonstrated with high resolution data from WorldView-4 satellite.

  19. Revisiting the ‘Low BirthWeight paradox’ using a model-based definition

    National Research Council Canada - National Science Library

    Juárez, Sol; Ploubidis, George B; Clarke, Lynda

    2014-01-01

    ...) babies in comparison to Spaniards (LBW paradox). This study aimed at revisiting this finding by applying a model-based threshold as an alternative to the conventional definition of LBW. Methods...

  20. Revisiting Chinese Cultural Issues in Peer Feedback in EFL Writing: Insights from a Multiple Case Study

    National Research Council Canada - National Science Library

    Yu, Shulin; Lee, Icy; Mak, Pauline

    2016-01-01

    The present case study aims to revisit the role of Chinese traditional cultural issues in group peer feedback by examining how Chinese EFL students respond to several typical Chinese cultural issues...

  1. Model-based satellite image fusion

    DEFF Research Database (Denmark)

    Aanæs, Henrik; Sveinsson, J. R.; Nielsen, Allan Aasbjerg

    2008-01-01

    A method is proposed for pixel-level satellite image fusion derived directly from a model of the imaging sensor. By design, the proposed method is spectrally consistent. It is argued that the proposed method needs regularization, as is the case for any method for this problem. A framework for pixel...... neighborhood regularization is presented. This framework enables the formulation of the regularization in a way that corresponds well with our prior assumptions of the image data. The proposed method is validated and compared with other approaches on several data sets. Lastly, the intensity......-hue-saturation method is revisited in order to gain additional insight of what implications the spectral consistency has for an image fusion method....

  2. Surface morphology and in-plane-epitaxy of SmBa2Cu3O7-δ films on SrTiO3 (001) substrates studied by STM and grazing incidence x-ray diffraction

    DEFF Research Database (Denmark)

    Jiang, Q.D.; Smilgies, D.M.; Feidenhans'l, R.

    1996-01-01

    The surface morphology and in-plane epitaxy of thin films of SmBa(2)Cu3O(7-delta) (Sm-BCO) grown on SrTiO3 (001) substrates with various thicknesses have been investigated by scanning tunneling microscopy (STM) and grazing incidence x-ray diffraction (GIXRD). As revealed by GIXRD, SmBCO films...... as thick as 500 Angstrom grow pseudomorphically on SrTiO3 (001) surfaces, in comparison with a maximum of 130 Angstrom for YBCO. This is probably due to a better lattice match of SmBCO (epsilon(alpha) = 1.2%, epsilon(b)=-0.5%) compared to YBCO (epsilon(alpha)=2.0%, epsilon(b)=0.5%) with the SrTiO3...

  3. Balancing Officer Community Manpower through Decentralization: Granular Programming Revisited (1REV)

    Science.gov (United States)

    2017-08-01

    Decentralization: Granular Programming Revisited Amanda Kraus, Jared Huff, and Elliot Lee August 2017 This work was performed under...Exchange Program or by other means. 8/28/2017 Request additional copies of this document through inquiries@cna.org. Approved by: August 2017...Officer Community Manpower through 5a. CONTRACT NUMBER N00014-16-D-5003 Decentralization: Granular Programming Revisited 5b. GRANT NUMBER 5c. PROGRAM

  4. Association of emergency department albuterol dispensing with pediatric asthma revisits and readmissions.

    Science.gov (United States)

    Hall, A Brad; Novotny, April; Bhisitkul, Donna M; Melton, James; Regan, Tim; Leckie, Maureen

    2017-06-01

    Although pediatric asthma continues to be a highly studied disease, data to suggest clear strategies to decrease asthma related revisits or readmissions is lacking. The purpose of our study was to assess the effect of emergency department (ED) direct dispensing of beta-agonist metered dose inhalers on pediatric asthma ED revisit and readmission rates. We conducted a retrospective cohort study of pediatric patients discharged from the pediatric ED with a diagnosis of asthma. Our primary outcome measured the rate of asthma revisits to the ED or admissions to the hospital within 28 days. Logistic regression analysis was used to assess ED beta-agonist MDI dispensing and revisit and/or readmission as the outcome. A total of 853 patients met eligibility for inclusion in the study, with 657 enrolled in the Baseline group and 196 enrolled in the ED-MDI group. The Baseline group experienced a revisit and readmission rate of 7.0% (46/657) versus 2.6% (5/196) in the ED-MDI group, (p = 0.026). ED direct dispensing of MDIs was found to be independently associated with a decreased risk of revisit or readmission (odds ratio 0.37; 95% confidence interval 0.14-0.95). In our study, ED direct dispensing of beta-agonist MDIs resulted in a reduction in 28-day revisit and readmission to the hospital. Further studies should be performed to evaluate the economic impact of reducing these revisits and readmissions against the costs of maintaining a dispensing program. Our findings may support modification of asthma programs to include dispensing MDIs from the emergency department.

  5. Revisiting the Decision of Death in Hurst v. Florida.

    Science.gov (United States)

    Cooke, Brian K; Ginory, Almari; Zedalis, Jennifer

    2016-12-01

    The United States Supreme Court has considered the question of whether a judge or a jury must make the findings necessary to support imposition of the death penalty in several notable cases, including Spaziano v. Florida (1984), Hildwin v. Florida (1989), and Ring v. Arizona (2002). In 2016, the U.S. Supreme Court revisited the subject in Hurst v. Florida Florida Statute § 921.141 allows the judge, after weighing aggravating and mitigating circumstances, to enter a sentence of life imprisonment or death. Before Hurst, Florida's bifurcated sentencing proceedings included an advisory sentence from jurors and a separate judicial hearing without juror involvement. In Hurst, the Court revisited the question of whether Florida's capital sentencing scheme violates the Sixth Amendment, which requires a jury, not a judge, to find each fact necessary to impose a sentence of death in light of Ring In an eight-to-one decision, the Court reversed the judgment of the Florida Supreme Court, holding that the Sixth Amendment requires a jury to find the aggravating factors necessary for imposing the death penalty. The role of Florida juries in capital sentencing proceedings was thereby elevated from advisory to determinative. We examine the Court's decision and offer commentary regarding this shift from judge to jury in the final imposition of the death penalty and the overall effect of this landmark case. © 2016 American Academy of Psychiatry and the Law.

  6. [Twentieth-century Penelopes: popular culture revisited].

    Science.gov (United States)

    Favaro, Cleci Eulalia

    2010-01-01

    During their settlement of the so-called Old Italian Colonies of Rio Grande do Sul, immigrants constructed a set of positive values that were to serve as an emotional support and a means of outside communication. When women immigrants embroidered images and sayings on wall hangings or kitchen towels made of rustic fabric, they helped nourish the dream of a better life, sought by all and achieved by some. The objects crafted by these twentieth-century Penelopes bear witness to a way of doing, thinking, and acting. Local museums and exhibits have fostered the recovery of old-time embroidery techniques and themes; sold at open-air markets and regional festivals, these products represent income for women whose age excludes them from the formal labor market.

  7. Imaging and manipulation of a polar molecule on Ag(111)

    DEFF Research Database (Denmark)

    Lin, R.; Braun, K.F.; Tang, H.

    2001-01-01

    A scanning tunneling microscope (STM) was applied to image and laterally manipulate isolated phosphangulene molecules on Ag(111) at 6 K. Atomic-resolution images clearly revealed three characteristic types of appearances (three-lobed, fish and bump shape) for the adsorbed molecules, which could...... correspond to three distinct binding configurations. From a detailed analysis of the relative distance between neighboring three-lobed molecules we determine the adsorption site. Applying the lateral manipulation technique ws demonstrate that the molecule can be pulled, slid or pushed by the tip...... on the surface. Accompanying with the reposition, molecular rotation and/or changing of binding configurations can also be induced. It is found that the dipole moment of the molecule has minor effects on its lateral movement. The results demonstrate that due to many degrees of freedom for large molecules...

  8. Anterior Commissure-posterior commissure revisited

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sang Han; Chi, Je Geun; Kim, Young Bo; Cho, Zang Hee [Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon (Korea, Republic of)

    2013-08-15

    The anterior commissure (AC) and posterior commissure (PC) are the two distinct anatomic structures in the brain which are difficult to observe in detail with conventional MRI, such as a 1.5T MRI system. However, recent advances in ultra-high resolution MRI have enabled us to examine the AC and PC directly. The objective of the present study is to standardize the shape and size of the AC and PC using a 7.0T MRI and to propose a new brain reference line. Thirty-four, 21 males and 13 females, healthy volunteers were enrolled in this study. After determining the center of each AC and PC, we defined the connection of these centers as the central intercommissural line (CIL). We compared the known extra- and intra-cerebral reference lines with the CIL to determine the difference in the angles. Additionally, we obtained horizontal line from flat ground line of look front human. The difference in angle of the CIL and the tangential intercommissural line (TIL) from the horizontal line was 8.7 ± 5.1 (11 ± 4.8) and 17.4 ± 5.2 (19.8 ± 4.8) degrees in males and females, respectively. The difference in angle between the CIL and canthomeatal line was 10.1 in both male and female, and there was no difference between both sexes. Likewise, there was no significant difference in angle between the CIL and TIL between both sexes (8.3 +/- 1.1 in male and 8.8 +/- 0.7 in female). In this study, we have used 7.0T MRI to define the AC and PC quantitatively and in a more robust manner. We have showed that the CIL is a reproducible reference line and serves as a standard for the axial images of the human brain.

  9. Self-recognition in pigeons revisited.

    Science.gov (United States)

    Uchino, Emiko; Watanabe, Shigeru

    2014-11-01

    Recognition of a self-image in a mirror is investigated using the mark test during which a mark is placed onto a point on the body that is not directly visible, and the presence or absence of self-directed behaviors is evaluated for the mirror-observing subjects. Great apes, dolphins, possibly elephants, and magpies have all passed the mark test, that is, displayed self-directed behaviors, whereas monkeys, crows, and other animals have failed the test even though they were able to use a mirror to find a not-directly-visible object. Self-directed behavior and mirror use are prerequisites of a successful mark test, and the absence of these behaviors may lead to false negative results. Epstein, Lanza, and Skinner (1981) reported self-directed behavior of pigeons in front of a mirror after explicit training of self-directed pecking and of pecking an object with the aid of a mirror, but certain other researchers could not confirm the results. The aim of the present study was to conduct the mark test with two pigeons that had received extensive training of the prerequisite behaviors. Crucial points of the training were identical topography (pecking) and the same reinforcement (food) in the prerequisite behaviors as well as sufficient training of these behaviors. After training for the prerequisite behaviors, both pigeons spontaneously integrated the learned self-directed and mirror-use behavior and displayed self-directed behavior in a mark test. This indicates that pigeons display mirror self-recognition after training of suitable ontogenetic contingency. © Society for the Experimental Analysis of Behavior.

  10. Revisiting the Effectiveness of Large Optical Telescopes

    Directory of Open Access Journals (Sweden)

    V. V. Sychev

    2015-01-01

    . Once again the conclusion drawn by the author in March, 2000 [11] is confirmed: there is no common sense to create telescopes of land basing with a diameter of the main mirror more than 25 m to register images of extremely remote astronomical objects. And creation of telescopes with diameters from 30 to 100 m, as it is seen from calculations, does not give any advantages over telescopes of smaller diameter, and only extremely complicates and raises the price of a problem.It is shown that introduction of new concept of an invariant of informational content for large-size optical telescopes will allow to have a new look at the development process of complicated optic-electronic complexes. The informational content invariant as a criterion of efficiency enables an assessment and comparison of various technical solutions at the stage of search for optimum ways of increasing informational content of telescopes.Besides, and it is quite essential, the invariant of informational content will disable the misapprehension regarding a possibility to increase amount of information by increasing a mirror diameter of the telescope and will prevent the scientific-and technological community from unsuccessful projects and unjustified material inputs.In the early 1990’s when design and implementation of the fourth generation of optical telescopes of a 10-meter class were under development scientists and engineers already started being engaged in problems of creating the super telescopes of the 5-th generation (25-meter and more. In recent years of the XX century when implementation of the main projects of telescopes of the fourth generation entered the finishing phase, these researches started extending and going deep. Despite the complicated problems the offers of 25-meter telescopes were followed by the avant-projects of telescopes with an aperture of 50 meters, and even 100 meters:- influence of laser radiation on design elements and propagation medium and, as consequence, the

  11. Stimulated Brillouin scattering revisited: Strong coupling regime and Rabi splitting

    CERN Document Server

    Huy, Kien Phan; Tchahame, Joel Cabrel; Sylvestre, Thibaut

    2015-01-01

    Stimulated Brillouin scattering in optical waveguides is a fundamental interaction between light and acoustic waves mediated by electrostriction and photoelasticity. In this paper, we revisit the usual theory of this inelastic scattering process to get a joint system in which the acoustic wave is strongly coupled to the interference pattern between the optical waves. We show in particular that, when the optoacoustic coupling rate is comparable to the phonon damping rate, the system enters in the strong coupling regime, giving rise to avoided crossing of the dispersion curve and Rabi-like splitting. We further find that optoacoustic Rabi splitting could in principle be observed using backward stimulated Brillouin scattering in sub-wavelength diameter tapered optical fibers with moderate peak pump power.

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

    Directory of Open Access Journals (Sweden)

    Hirokazu Takahashi

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

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

    Science.gov (United States)

    Takahashi, Hirokazu; Yokota, Ryo; Kanzaki, Ryohei

    2013-01-01

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

  14. Energy in synthetic fertilizers and pesticides: Revisited. Final project report

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, M.G.; English, B.C.; Turhollow, A.F.; Nyangito, H.O. [Tennessee Univ., Knoxville, TN (United States). Dept. of Agricultural Economics and Rural Sociology

    1994-01-01

    Agricultural chemicals that are derived from fossil-fuels are the major energy intensive inputs in agriculture. Growing scarcity of the world`s fossil resources stimulated research and development of energy-efficient technology for manufacturing these chemicals in the last decade. The purpose of this study is to revisit the energy requirements of major plant nutrients and pesticides. The data from manufacturers energy survey conducted by The Fertilizer Institute are used to estimate energy requirements of fertilizers. Energy estimates for pesticides are developed from consulting previously published literature. The impact of technical innovation in the fertilizer industry to US corn, cotton, soybean and wheat producers is estimated in terms of energy-saving.

  15. Revisiting the Response Mechanism of Polymeric Membrane Based Heparin Electrodes.

    Science.gov (United States)

    Bell, Andrea K; Höfler, Lajos; Meyerhoff, Mark E

    2012-01-01

    Potentiometric membrane electrodes that respond to heparin and other polyanions were introduced in the early 1990s. Herein, the mechanism of polymer membrane electrode type heparin sensors is revisited. The extraction/diffusion of heparin is studied via both potentiometric and impedance spectroscopic techniques using a pre-fractionated heparin preparation that contains polyanionic species > 10000 Daltons. The reversal in EMF response using this heparin preparation indicates diffusion of higher MW heparin fragments to the backside of the membrane. Diffusion coefficients are calculated using a novel formula derived from the phase boundary potential model and Fick's second law of diffusion. Impedance spectroscopy is also employed to show that high MW heparin species are extracted and diffuse across the PVC membranes.

  16. Revisiting the thermodynamic relations in AdS /CMT models

    Science.gov (United States)

    Hyun, Seungjoon; Park, Sang-A.; Yi, Sang-Heon

    2017-03-01

    Motivated by the recent unified approach to the Smarr-like relation of anti-de Sitter (AdS) planar black holes in conjunction with the quasilocal formalism on conserved charges, we revisit the quantum statistical and thermodynamic relations of hairy AdS planar black holes. By extending the previous results, we identify the hairy contribution in the bulk and show that the holographic computation can be improved so that it is consistent with the bulk computation. We argue that the first law can be retained in its universal form and that the relation between the on-shell renormalized Euclidean action and its free energy interpretation in gravity may also be undeformed even with the hairy contribution in hairy AdS black holes.

  17. Revisiting Johnson and Jackson boundary conditions for granular flows

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tingwen; Benyahia, Sofiane

    2012-07-01

    In this article, we revisit Johnson and Jackson boundary conditions for granular flows. The oblique collision between a particle and a flat wall is analyzed by adopting the classic rigid-body theory and a more realistic semianalytical model. Based on the kinetic granular theory, the input parameter for the partial-slip boundary conditions, specularity coefficient, which is not measurable in experiments, is then interpreted as a function of the particle-wall restitution coefficient, the frictional coefficient, and the normalized slip velocity at the wall. An analytical expression for the specularity coefficient is suggested for a flat, frictional surface with a low frictional coefficient. The procedure for determining the specularity coefficient for a more general problem is outlined, and a working approximation is provided.

  18. The General Motor Ability Hypothesis: An Old Idea Revisited.

    Science.gov (United States)

    Hands, Beth; McIntyre, Fleur; Parker, Helen

    2018-01-01

    While specific motor abilities have become a popular explanation for motor performance, the older, alternate notion of a general motor ability should be revisited. Current theories lack consensus, and most motor assessment tools continue to derive a single composite score to represent motor capacity. In addition, results from elegant statistical procedures such as higher order factor analyses, cluster analyses, and Item Response Theory support a more global motor ability. We propose a contemporary model of general motor ability as a unidimensional construct that is emergent and fluid over an individual's lifespan, influenced by both biological and environmental factors. In this article, we address the implications of this model for theory, practice, assessment, and research. Based on our hypothesis and Item Response Theory, our Lifespan Motor Ability Scale can identify motor assessment tasks that are relevant and important across varied phases of lifespan development.

  19. Gospel, culture and mission: Revisiting an enduring problem

    Directory of Open Access Journals (Sweden)

    O.U. Kalu

    1998-08-01

    Full Text Available Gospel, culture and mission: Revisiting an enduring problem This article reflects on the 1996 Conference on World Mission and Evangelism. The relation between gospel, culture and mission is considered, especially from an Africa perspective, but not reserved to it in application. Apart from considering the problem of appropriate terminology to express the intricacies concerning the subject, a deeper search is conducted into the complex relationship between the believer, his mission to, and his distancing from divergent cultural sources and manifestations. Emerging perspectives are considered, which help to formulate mission strategies and historic viewpoints and attitudes. Knowledge of these perspectives is essential for a more responsible answering to the call made to all believers.

  20. Simulation of Two-Way Pushdown Automata Revisited

    Directory of Open Access Journals (Sweden)

    Robert Glück

    2013-09-01

    Full Text Available The linear-time simulation of 2-way deterministic pushdown automata (2DPDA by the Cook and Jones constructions is revisited. Following the semantics-based approach by Jones, an interpreter is given which, when extended with random-access memory, performs a linear-time simulation of 2DPDA. The recursive interpreter works without the dump list of the original constructions, which makes Cook's insight into linear-time simulation of exponential-time automata more intuitive and the complexity argument clearer. The simulation is then extended to 2-way nondeterministic pushdown automata (2NPDA to provide for a cubic-time recognition of context-free languages. The time required to run the final construction depends on the degree of nondeterminism. The key mechanism that enables the polynomial-time simulations is the sharing of computations by memoization.

  1. Revisiting a Classic Study of the Molecular Clock.

    Science.gov (United States)

    Robinson, Lauren M; Boland, Joseph R; Braverman, John M

    2016-03-01

    A constant rate of molecular evolution among homologous proteins and across lineages is known as the molecular clock. This concept has been useful for estimating divergence times. Here, we revisit a study by Richard Dickerson (J Mol Evol 1:26-45, 1971), wherein he provided striking visual evidence for a constant rate of amino acid changes among various evolutionary branch points. Dickerson's study is commonly cited as support of the molecular clock and a figure from it is often reproduced in textbooks. Since its publication, however, there have been updates made to dates of common ancestors based on the fossil record that should be considered. Additionally, collecting the accession numbers and carefully outlining Dickerson's methods serves as a resource to students of the molecular clock hypothesis.

  2. Dynamics of Shape Fluctuations of Quasi-spherical Vesicles Revisited

    DEFF Research Database (Denmark)

    Miao, L.; Lomholt, Michael Andersen; Kleis, J.

    2002-01-01

    of the phenomenological constants in a canonical continuum description of fluid lipid-bilayer membranes and shown the consequences of this new interpretation in terms of the characteristics of the dynamics of vesicle shape fluctuations. Moreover, we have used the systematic formulation of our theory as a framework...... against which we have discussed the previously existing theories and their discrepancies. Finally, we have made a systematic prediction about the system-dependent characteristics of the relaxation dynamics of shape fluctuations of quasi-spherical vesicles with a view of experimental studies......In this paper, the dynamics of spontaneous shape fluctuations of a single, giant quasi-spherical vesicle formed from a single lipid species is revisited theoretically. A coherent physical theory for the dynamics is developed based on a number of fundamental principles and considerations...

  3. Revisiting lowest possible surface energy of a solid

    Science.gov (United States)

    Chen, Zhou; Nosonovsky, Michael

    2017-12-01

    The solid–vapor surface energy cannot be determined directly from the contact angle data because the Young equation includes three unknown interfacial energies. While the liquid–vapor energy is usually known, different theories can be used to exclude the solid–liquid energy, such as Antonoff, Zisman, Fowkes, and Owens and Wendt theories. These theories yield significantly different results for the solid–vapor surface energy. We revisit the claim that the lowest surface energy is 6.7 mJ m‑2 of C20F42, while polytetrafluoroethylene’s surface energy is 22 mJ m‑2. These numbers can change significantly if a different theory is used.

  4. Online haemodiafiltration: definition, dose quantification and safety revisited.

    Science.gov (United States)

    Tattersall, James E; Ward, Richard A

    2013-03-01

    The general objective assigned to the EUropean DIALlysis (EUDIAL) Working Group by the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) was to enhance the quality of dialysis therapies in Europe in the broadest possible sense. Given the increasing interest in convective therapies, the Working Group has started by focusing on haemodiafiltration (HDF) therapies. Several reports suggest that those therapies potentially improve the outcomes for end-stage renal disease patients. Europe is the leader in the field, having introduced the concept of ultra-purity for water and dialysis fluids and with notified bodies of the European Community having certified water treatment systems and online HDF machines. The prevalence of online HDF-treated patients is steadily increasing in Europe, averaging 15%. A EUDIAL consensus conference was held in Paris on 13 October 2011 to revisit terminology, safety and efficacy of online HDF. This is the first report of the expert group arising from that conference.

  5. Revisiting Black Holes as Dark Matter

    Science.gov (United States)

    Kohler, Susanna

    2017-02-01

    Could dark matter be made of intermediate-mass black holes formed in the beginning of the universe? A recent study takes a renewed look at this question.Galactic LurkersThe nature of dark matter has long been questioned, but the recent discovery of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) has renewed interest in the possibility that dark matter could consist of primordial black holes in the mass range of 101000 solar masses.The relative amounts of the different constituents of the universe. Dark matter makes up roughly 27%. [ESA/Planck]According to this model, the extreme density of matter present during the universes early expansion led to the formation of a large number of intermediate-mass black holes. These black holes now hide in the halos of galaxies, constituting the mass that weve measured dynamically but remains unseen.LIGOs first gravitational-wave detection revealed the merger of two black holes that were both tens of solar masses in size. If primordial black holes are indeed a major constituent of dark matter, then LIGOs detection is consistent with what we would expect to find: occasional mergers of the intermediate-mass black holes that formed in the early universe and now lurk in galactic halos.Quasar MicrolensingTheres a catch, however. If there truly were a large number of intermediate-mass primordial black holes hiding in galactic halos, they wouldnt go completely unnoticed: we would see signs of their presence in the gravitational microlensing of background quasars. Unseen primordial black holes in a foreground galaxy could cause an image of a background quasar to briefly brighten which would provide us with clear evidence of such black holes despite our not being able to detect them directly.A depiction of quasar microlensing (click for a closer look!). The microlensing object in the foreground galaxy could be a star (as depicted), a primordial black hole, or any other compact object. [NASA

  6. Electron standing waves on the GaN(0001)-pseudo (1 × 1) surface: a FT-STM study at room temperature.

    Science.gov (United States)

    Sun, G F; Liu, Y; Qi, Y; Jia, J F; Xue, Q K; Weinert, M; Li, L

    2010-10-29

    We report the direct imaging of standing waves on a GaN(0001)-pseudo (1 × 1) metallic surface, which consists of two atomic Ga layers with the top layer incommensurate. Two types of periodic oscillation are observed by scanning tunneling microscopy at room temperature. The longer wavelength standing waves are due to electron scattering by dislocation-induced steps and two-dimensional InN islands. The localized shorter wavelength waves are attributed to a structural transition of the incommensurate Ga bilayer to a tetrahedral Ga bilayer after the growth of the InN islands.

  7. Non-invasive assessment of bone quantity and quality in human trabeculae using scanning ultrasound imaging

    Science.gov (United States)

    Xia, Yi

    Fractures and associated bone fragility induced by osteoporosis and osteopenia are widespread health threat to current society. Early detection of fracture risk associated with bone quantity and quality is important for both the prevention and treatment of osteoporosis and consequent complications. Quantitative ultrasound (QUS) is an engineering technology for monitoring bone quantity and quality of humans on earth and astronauts subjected to long duration microgravity. Factors currently limiting the acceptance of QUS technology involve precision, accuracy, single index and standardization. The objective of this study was to improve the accuracy and precision of an image-based QUS technique for non-invasive evaluation of trabecular bone quantity and quality by developing new techniques and understanding ultrasound/tissue interaction. Several new techniques have been developed in this dissertation study, including the automatic identification of irregular region of interest (iROI) in bone, surface topology mapping (STM) and mean scattering spacing (MSS) estimation for evaluating trabecular bone structure. In vitro results have shown that (1) the inter- and intra-observer errors in QUS measurement were reduced two to five fold by iROI compared to previous results; (2) the accuracy of QUS parameter, e.g., ultrasound velocity (UV) through bone, was improved 16% by STM; and (3) the averaged trabecular spacing can be estimated by MSS technique (r2=0.72, prisk by monitoring of bone's quality. The developed QUS imaging technique can be used to assess bone's quantity and quality with improved accuracy and precision.

  8. Coherent interferometric imaging, time gating and beamforming

    Science.gov (United States)

    Borcea, Liliana; Garnier, Josselin; Papanicolaou, George; Tsogka, Chrysoula

    2011-06-01

    Coherent interferometric imaging is based on the backpropagation of local spacetime cross-correlations of array data and was introduced in order to improve images when the medium between the array and the object to be imaged is inhomogeneous and unknown (Borcea et al 2005 Inverse Problems 21 1419). Although this method has been shown to be effective and is well founded theoretically, the coherent interferometric imaging function is computationally expensive and therefore difficult to use. In this paper, we show that this function is equivalent to a windowed beamformer energy function, that is, a quadratic function that involves only time gating and time delaying signals in emission and in reception. In this form the coherent interferometric imaging can be implemented efficiently both in hardware and software, that is, at a computational cost that is comparable to the usual beamforming and migration imaging methods. We also revisit the trade-off between enhanced image stability and loss of resolution in coherent interferometry from the point of view of its equivalence to a windowed beamformer energy imaging function.

  9. Final Technical Report for SISGR: Ultrafast Molecular Scale Chemical Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hersam, Mark C. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Guest, Jeffrey R. [Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials; Guisinger, Nathan P. [Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials; Hla, Saw Wai [Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials; Schatz, George C. [Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Seideman, Tamar [Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Van Duyne, Richard P. [Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry

    2017-04-10

    The Northwestern-Argonne SISGR program utilized newly developed instrumentation and techniques including integrated ultra-high vacuum tip-enhanced Raman spectroscopy/scanning tunneling microscopy (UHV-TERS/STM) and surface-enhanced femtosecond stimulated Raman scattering (SE-FSRS) to advance the spatial and temporal resolution of chemical imaging for the study of photoinduced dynamics of molecules on plasmonically active surfaces. An accompanying theory program addressed modeling of charge transfer processes using constrained density functional theory (DFT) in addition to modeling of SE-FSRS, thereby providing a detailed description of the excited state dynamics. This interdisciplinary and highly collaborative research resulted in 62 publications with ~ 48% of them being co-authored by multiple SISGR team members. A summary of the scientific accomplishments from this SISGR program is provided in this final technical report.

  10. Powell’s Leadership Principles -- Time for State Department to Revisit

    Science.gov (United States)

    2009-01-20

    Richard L. Daft and Karl E. Weick, “Toward a Model of Organizations as Interpretation Systems,” Academy of Management Review, IX, no. 2 (1984), reprinted...St ra te gy Re se ar ch Pr oj ec t POWELL’S LEADERSHIP PRINCIPLES – TIME FOR STATE DEPARTMENT TO REVISIT BY MICHELLE L. STEFANICK United States...TITLE AND SUBTITLE Powell’s Leadership Principles- Time for State Department to Revisit 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  11. The Effects of Korean Medical Service Quality and Satisfaction on Revisit Intention of the United Arab Emirates Government Sponsored Patients.

    Science.gov (United States)

    Lee, Seoyoung; Kim, Eun-Kyung

    2017-06-01

    The purpose of this study was to investigate medical service quality, satisfaction and to examine factors influencing hospital revisit intention of the United Arab Emirates government sponsored patients in Korea. A total of 152 UAE government sponsored patients who visited Korean hospitals participated in the questionnaire survey from August to November 2016. Stepwise multiple regression was used to identify the factors that affected the revisit intention of the participants. The mean scores of medical service quality, satisfaction, and revisit intention were 5.72 out of 7, 88.88 out of 100, 4.59 out of 5, respectively. Medical service quality and satisfaction, Medical service quality and revisit intention, satisfaction and revisit intention were positively correlated. Medical service of physician, visiting routes and responsiveness of medical service quality explained about 23.8% of revisit intention. There are needs for physicians to communicate with patients while ensuring sufficient consultation time based on excellent medical skills and nurses to respond immediately for the patients' needs through an empathic encounter in order to improve medical service quality and patient satisfaction so that to increase the revisit intention of the United Arab Emirates government sponsored patients. Further, it is necessary for the hospitals to have support plans for providing country specialized services in consideration of the UAE culture to ensure that physicians' and nurses' competencies are not undervalued by non-medical service elements such as interpreters and meals. Copyright © 2017. Published by Elsevier B.V.

  12. Revisit Frequency and Its Association with Quality of Care among Diabetic Patients: Translating Research Into Action for Diabetes (TRIAD)

    Science.gov (United States)

    Asao, Keiko; McEwen, Laura N.; Crosson, Jesse C.; Waitzfelder, Beth; Herman, William H.

    2014-01-01

    Objective To describe patient and provider characteristics associated with outpatient revisit frequency and to examine the associations between the revisit frequency and the processes and intermediate outcomes of diabetes care. Research Design and Methods We analyzed data from Translating Research Into Action for Diabetes (TRIAD), a prospective, multicenter, observational study of diabetes care in managed care. Results Our analysis included 6,040 eligible adult participants with type 2 diabetes (42.6% ≥ 65 years of age, 54.1% female) whose primary care providers were the main provider of the participants’ diabetes care. The median (interquartile range) revisit frequency was 4.0 (3.7, 6.0) visits per year. Being female, having lower education, lower income, more complex diabetes treatment, cardiovascular disease, higher Charlson comorbidity index, and impaired mobility were associated with higher revisit frequency. The proportion of participants who had annual assessments of HbA1c and LDL-cholesterol, foot examinations, advised or documented aspirin use, and influenza immunizations were higher for those with higher revisit frequency. The proportion of participants who met HbA1c (frequency. The predicted probabilities of achieving more aggressive goals, HbA1c frequency. Conclusions Revisit frequency was highly variable and was associated with both sociodemographic characteristics and disease severity. A higher revisit frequency was associated with better processes of diabetes care, but the association with intermediate outcomes was less clear. PMID:25044233

  13. Franklin Delano Roosevelt: The Diagnosis of Poliomyelitis Revisited.

    Science.gov (United States)

    Ditunno, John F; Becker, Bruce E; Herbison, Gerald J

    2016-09-01

    Revisiting the ailments of famous historical persons in light of contemporary medical understanding has become a common academic hobby. Public discussion of Franklin Delano Roosevelt's (FDR) diagnosis of poliomyelitis after his sudden onset of paralysis in 1921 has received just such a revisitation. Recently, this 2003 historical analysis has been referenced widely on the Internet and in biographies, raising speculation that his actual diagnosis should have been Guillain-Barré Syndrome, a noncontagious disease of the peripheral nervous system rather than poliomyelitis. The authors of that 2003 analysis used a statistical analysis of his case by selectively choosing some of his reported symptoms. FDR's diagnosis of poliomyelitis, however, was fully supported by the findings of leading expert physicians of that time, who were very knowledgeable in the then-common disease and who periodically examined him during the period of 1921-1924. The most significant diagnostic features of polio are the absence of objective sensory findings in the presence of flaccid motor paralysis. These features are consistent with diagnostic criteria extant during the periods of major poliomyelitis epidemics as well as those of the Center for Disease Control 90 years later. Additional findings of fever, prodromal hyperesthesia, more severe residual proximal muscle weakness, and extensive lower extremity impairment requiring mobility with long leg braces or a wheelchair give further evidence for the diagnosis in FDR's case. Nonbulbar Guillain-Barré Syndrome, which shares the features of a flaccid paralysis and thus mimicking the initial presentation of poliomyelitis, has more than an 80% complete recovery with no reported cases of eventual wheelchair use. The most severe cases of Guillain-Barré Syndrome often have persistent objective sensory loss, associated with greater weakness in the feet and hands, which show no resemblance to FDR's impairment and disability. In light of the expert

  14. Spectroscopic properties of photosystem II reaction center revisited

    Science.gov (United States)

    Gelzinis, Andrius; Abramavicius, Darius; Ogilvie, Jennifer P.; Valkunas, Leonas

    2017-09-01

    Photosystem II (PSII) is the only biological system capable of splitting water to molecular oxygen. Its reaction center (RC) is responsible for the primary charge separation that drives the water oxidation reaction. In this work, we revisit the spectroscopic properties of the PSII RC using the complex time-dependent Redfield (ctR) theory for optical lineshapes [A. Gelzinis et al., J. Chem. Phys. 142, 154107 (2015)]. We obtain the PSII RC model parameters (site energies, disorder, and reorganization energies) from the fits of several spectra and then further validate the model by calculating additional independent spectra. We obtain good to excellent agreement between theory and calculations. We find that overall our model is similar to some of the previous asymmetric exciton models of the PSII RC. On the other hand, our model displays differences from previous work based on the modified Redfield theory. We extend the ctR theory to describe the Stark spectrum and use its fit to obtain the parameters of a single charge transfer state included in our model. Our results suggest that C h lD1 +P h e oD1 - is most likely the primary charge transfer state, but that the Stark spectrum of the PSII RC is probably also influenced by other states.

  15. Biogas from Macroalgae: is it time to revisit the idea?

    Directory of Open Access Journals (Sweden)

    Hughes Adam D

    2012-11-01

    Full Text Available Abstract The economic and environmental viability of dedicated terrestrial energy crops is in doubt. The production of large scale biomass (macroalgae for biofuels in the marine environment was first tested in the late 1960’s. The culture attempts failed due to the engineering challenges of farming offshore. However the energy conversion via anaerobic digestion was successful as the biochemical composition of macroalgae makes it an ideal feedstock. The technology for the mass production of macroalgae has developed principally in China and Asia over the last 50 years to such a degree that it is now the single largest product of aquaculture. There has also been significant technology transfer and macroalgal cultivation is now well tried and tested in Europe and America. The inherent advantage of production of biofuel feedstock in the marine environment is that it does not compete with food production for land or fresh water. Here we revisit the idea of the large scale cultivation of macroalgae at sea for subsequent anaerobic digestion to produce biogas as a source of renewable energy, using a European case study as an example.

  16. ISLAM, ADAT, AND THE STATE: Matrifocality in Aceh Revisited

    Directory of Open Access Journals (Sweden)

    Eka Srimulyani

    2010-08-01

    Full Text Available Matrifocality has been a rooted tradition in the social history of the community in Aceh. The principles of matrifocality have also affected on how women are positioned in the community, and the socio-gender relation within the community. The fact that Aceh has strongly associated to the Islamic values that claimed to support the paternal traditions. Apparently, the Islamic values and the local matrifocality practices juxtaposed through the roles of adat, which considered as inseparable to Islamic law or teaching, or in local term known as zat ngeun sifeut. Another point in revisiting matrifocality in Aceh in Aceh is an examination of how gender state ideology, particularly during the New Order Regime disregarded some local gender practices across some ethnics in the archipelago. Meanwhile, the state also hegemonied and promoted particular gender state ideology such as state ibuism. Nonetheless, the modernity and social changes have also contributed to the shifting of some matrifocality practices in contemporary Acehnese society. However, since the matrifocality has a strong root in the social life of the community, the principles of the matrifocality still survived until currently, although it transformed into ‘new matrifocality’ practices. Keywords: matrifocality, Aceh, gender, shari‘a law

  17. The interaction of atoms with LiF(001) revisited

    CERN Document Server

    Miraglia, J E

    2016-01-01

    Pairwise additive potentials for multielectronic atoms interacting with a LiF(001) surface are revisited by including an improved description of the electron density associated with the different lattice sites, as well as non-local electron density contributions. Within this model, the electron distribution around each ionic site of the crystal is described by means of an onion approach that accounts for the influence of the Madelung potential. From such densities, binary interatomic potentials are then derived by using well-known non-local functionals for the kinetic, exchange and correlation terms. Rumpling and long-range contributions due to projectile polarization and van der Waals forces are also included in an analogous fashion. We apply this pairwise additive approximation to evaluate the interaction potential between closed-shell - He, Ne, Ar, Kr, and Xe - and open-shell - N, S, and Cl - atoms and the LiF surface, analyzing the relative importance of the different contributions. The performance of the...

  18. Revisiting the monoamine hypothesis of depression: a new perspective.

    Science.gov (United States)

    Goldberg, Joel S; Bell, Clifton E; Pollard, David A

    2014-01-01

    As the incidence of depression increases, depression continues to inflict additional suffering to individuals and societies and better therapies are needed. Based on magnetic resonance spectroscopy and laboratory findings, gamma aminobutyric acid (GABA) may be intimately involved in the pathophysiology of depression. The isoelectric point of GABA (pI = 7.3) closely approximates the pH of cerebral spinal fluid (CSF). This may not be a trivial observation as it may explain preliminary spectrophotometric, enzymatic, and HPLC data that monoamine oxidase (MAO) deaminates GABA. Although MAO is known to deaminate substrates such as catecholamines, indoleamines, and long chain aliphatic amines all of which contain a lipophilic moiety, there is very good evidence to predict that a low concentration of a very lipophilic microspecies of GABA is present when GABA pI = pH as in the CSF. Inhibiting deamination of this microspecies of GABA could explain the well-established successful treatment of refractory depression with MAO inhibitors (MAOI) when other antidepressants that target exclusively levels of monoamines fail. If further experimental work can confirm these preliminary findings, physicians may consider revisiting the use of MAOI for the treatment of non-intractable depression because the potential benefits of increasing GABA as well as the monoamines may outweigh the risks associated with MAOI therapy.

  19. An Adaptive and Hybrid Approach for Revisiting the Visibility Pipeline

    Directory of Open Access Journals (Sweden)

    Ícaro Lins Leitão da Cunha

    2016-04-01

    Full Text Available We revisit the visibility problem, which is traditionally known in Computer Graphics and Vision fields as the process of computing a (potentially visible set of primitives in the computational model of a scene. We propose a hybrid solution that uses a dry structure (in the sense of data reduction, a triangulation of the type J1a, to accelerate the task of searching for visible primitives. We came up with a solution that is useful for real-time, on-line, interactive applications as 3D visualization. In such applications the main goal is to load the minimum amount of primitives from the scene during the rendering stage, as possible. For this purpose, our algorithm executes the culling by using a hybrid paradigm based on viewing-frustum, back-face culling and occlusion models. Results have shown substantial improvement over these traditional approaches if applied separately. This novel approach can be used in devices with no dedicated processors or with low processing power, as cell phones or embedded displays, or to visualize data through the Internet, as in virtual museums applications.

  20. Whistler oscillitons revisited: the role of charge neutrality?

    Directory of Open Access Journals (Sweden)

    F. Verheest

    2004-01-01

    Full Text Available When studying transverse modes propagating parallel to a static magnetic field, an apparent contradiction arises between the weakly nonlinear results obtained from the derivative nonlinear Schrödinger equation, predicting envelope solitons (where the amplitude is stationary in the wave frame, but the phase is not, and recent results for whistler oscillitons, indicating that really stationary structures of large amplitude are possible. Revisiting this problem in the fluid dynamic approach, care has been taken not to introduce charge neutrality from the outset, because this not only neglects electric stresses compared to magnetic stresses, which is reasonable, but could also imply from Poisson's equation a vanishing of the wave electric field. Nevertheless, the fixed points of the remaining equations are the same, whether charge neutrality is assumed from the outset or not, so that the solitary wave solutions at not too large amplitudes will be very similar. This is borne out by numerical simulations of the solutions under the two hypotheses, showing that the lack of correspondence with the DNLS envelope solitons indicates the limitations of the reductive perturbation approach, and is not a consequence of assuming charge neutrality.

  1. The Determination of $\\alpha_s$ from Tau Decays Revisited

    CERN Document Server

    Davier, M; Höcker, A; Malaescu, B; Zhang, Z

    2008-01-01

    We revisit the determination of alpha_s(m_tau) using a fit to inclusive tau hadronic spectral moments in light of (1) the recent calculation of the fourth-order perturbative coefficient K_4 in the expansion of the Adler function, (2) new precision measurements from BABAR of e+e- annihilation cross sections, which decrease the uncertainty in the separation of vector and axial-vector spectral functions, and (3) improved results from BABAR and Belle on tau branching fractions involving kaons. We estimate that the fourth-order perturbative prediction reduces the theoretical uncertainty, introduced by the truncation of the series, by 20% with respect to earlier determinations. We discuss to some detail the perturbative prediction and show that the effect of the incomplete knowledge of the series is reduced by using the so-called contour-improved calculation, as opposed to fixed-order perturbation theory which manifests convergence problems. The corresponding theoretical uncertainties are studied at the tau and Z m...

  2. Revisiting reflexology: Concept, evidence, current practice, and practitioner training

    Directory of Open Access Journals (Sweden)

    Nurul Haswani Embong

    2015-10-01

    Full Text Available Reflexology is basically a study of how one part of the human body relates to another part of the body. Reflexology practitioners rely on the reflexes map of the feet and hands to all the internal organs and other human body parts. They believe that by applying the appropriate pressure and massage certain spots on the feet and hands, all other body parts could be energized and rejuvenated. This review aimed to revisit the concept of reflexology and examine its effectiveness, practices, and the training for reflexology practitioners. PubMed, SCOPUS, Google Scholar, and SpringerLink databases were utilized to search the following medical subject headings or keywords: foot massage, reflexology, foot reflexotherapy, reflexological treatment, and zone therapy. The articles published for the last 10 years were included. Previous systematic reviews failed to show concrete evidence for any specific effect of reflexology in any conditions. Due to its non-invasive, non-pharmacological complementary nature, reflexology is widely accepted and anecdotal evidence of positive effect reflexology in a variety of health conditions are available. Adequate training for practitioners is necessary to ensure the consistency of service provided.

  3. Pyrochlore Oxide Superconductor Cd2Re2O7 Revisited

    Science.gov (United States)

    Hiroi, Zenji; Yamaura, Jun-ichi; Kobayashi, Tatsuo C.; Matsubayashi, Yasuhito; Hirai, Daigorou

    2018-02-01

    The superconducting pyrochlore oxide Cd2Re2O7 is revisited with a particular emphasis on the sample-quality issue. The compound has drawn attention as the only superconductor (Tc = 1.0 K) that has been found in the family of α-pyrochlore oxides since its discovery in 2001. Moreover, it exhibits two characteristic structural transitions from the cubic pyrochlore structure, with the inversion symmetry broken at the first one at 200 K. Recently, it has attracted increasing attention as a candidate spin-orbit coupled metal (SOCM), in which specific Fermi liquid instability is expected to lead to an odd-parity order with spontaneous inversion-symmetry breaking [L. Fu, Phys. Rev. Lett. 115, 026401 (2015)] and parity-mixing superconductivity [V. Kozii and L. Fu, Phys. Rev. Lett. 115, 207002 (2015); Y. Wang et al., Phys. Rev. B 93, 134512 (2016)]. We review our previous experimental results in comparison with those of other groups in the light of the theoretical prediction of the SOCM, which we consider meaningful and helpful for future progress in understanding this unique compound.

  4. Resonance effect in the allyl cation and anion: a revisit.

    Science.gov (United States)

    Mo, Yirong

    2004-08-20

    The interest over the magnitude of the conjugation effect in the allyl cation (1) and anion (2) has been revived recently by Barbour and Karty (J. Org. Chem. 2004, 69, 648-654), who derived the resonance energies of 20-22 and 17-18 kcal/mol for 1 and 2, respectively, using an empirical extrapolation approximation. This paper revisits the case by explicitly calculating the Pauling-Wheland resonance energy, which measures the stabilization from the most stable resonance structure to the delocalized energy-minimum state of a conjugated system, using our newly developed block-localized wave function (BLW) method. This BLW method has the geometrical optimization capability. The computations result in adiabatic resonance energies of 37 kcal/mol for 1 and 38 kcal/mol for 2. The significant disagreement between these values and Barbour and Karty's results originates from the neglect of structural and electronic variations in their derivation which are energy costing. Copyright 2004 American Chemical Society

  5. Sex combs reduced (Scr) regulatory region of Drosophila revisited.

    Science.gov (United States)

    Calvo-Martín, Juan M; Papaceit, Montserrat; Segarra, Carmen

    2017-08-01

    The Hox gene Sex combs reduced (Scr) is responsible for the differentiation of the labial and prothoracic segments in Drosophila. Scr is expressed in several specific tissues throughout embryonic development, following a complex path that must be coordinated by an equally complex regulatory region. Although some cis-regulatory modules (CRMs) have been identified in the Scr regulatory region (~75 kb), there has been no detailed and systematic study of the distinct regulatory elements present within this region. In this study, the Scr regulatory region was revisited with the aim of filling this gap. We focused on the identification of Initiator elements (IEs) that bind segmentation factors, Polycomb response elements (PREs) that are recognized by the Polycomb and Trithorax complexes, as well as insulators and tethering elements. To this end, we summarized all currently available information, mainly obtained from high throughput ChIP data projects. In addition, a bioinformatic analysis based on the evolutionary conservation of regulatory sequences using the software MOTEVO was performed to identify IE and PRE candidates in the Scr region. The results obtained by this combined strategy are largely consistent with the CRMs previously identified in the Scr region and help to: (i) delimit them more accurately, (ii) subdivide two of them into different independent elements, (iii) identify a new CRM, (iv) identify the composition of their binding sites and (v) better define some of their characteristics. These positive results indicate that an approach that integrates functional and bioinformatic data might be useful to characterize other regulatory regions.

  6. Revisiting the master-signifier, or, Mandela and repression

    Directory of Open Access Journals (Sweden)

    Derek eHook

    2016-01-01

    Full Text Available The concept of the master-signifier has been subject to a variety of applications in Lacanian forms of political discourse theory and ideology critique. While there is much to be commended in literature of this sort, it often neglects salient issues pertaining to the role of master signifiers in the clinical domain of (individual psychical economy. The popularity of the concept of the master (or ‘empty’ signifier in political discourse analysis has thus proved a double-edged sword. On the one hand it demonstrates how crucial psychical processes are performed via the operations of the signifier, extending thus the Lacanian thesis that identification is as much the outcome of linguistic and symbolic as opposed to merely psychological processes. On the other, the use of the master signifier concept within the political realm to track discursive formations tends to distance the term from the dynamics of the unconscious and operation of repression. Accordingly, this paper revisits the master signifier concept, and does so within the socio-political domain, yet while paying particular attention to the functioning of unconscious processes of fantasy and repression. More specifically, it investigates how Nelson Mandela operates as a master signifier in contemporary South Africa, as a vital means of knitting together diverse elements of post-apartheid society, enabling the fantasy of the post-apartheid nation, and holding at bay a whole series of repressed and negated undercurrents.

  7. Revisiting the Master-Signifier, or, Mandela and Repression.

    Science.gov (United States)

    Hook, Derek; Vanheule, Stijn

    2015-01-01

    The concept of the master-signifier has been subject to a variety of applications in Lacanian forms of political discourse theory and ideology critique. While there is much to be commended in literature of this sort, it often neglects salient issues pertaining to the role of master signifiers in the clinical domain of (individual) psychical economy. The popularity of the concept of the master (or "empty") signifier in political discourse analysis has thus proved a double-edged sword. On the one hand it demonstrates how crucial psychical processes are performed via the operations of the signifier, extending thus the Lacanian thesis that identification is the outcome of linguistic and symbolic as opposed to merely psychological processes. On the other, the use of the master signifier concept within the political realm to track discursive formations tends to distance the term from the dynamics of the unconscious and operation of repression. Accordingly, this paper revisits the master signifier concept, and does so within the socio-political domain, yet while paying particular attention to the functioning of unconscious processes of fantasy and repression. More specifically, it investigates how Nelson Mandela operates as a master signifier in contemporary South Africa, as a vital means of knitting together diverse elements of post-apartheid society, enabling the fantasy of the post-apartheid nation, and holding at bay a whole series of repressed and negated undercurrents.

  8. Psychological Well-Being Revisited: Advances in Science and Practice

    Science.gov (United States)

    Ryff, Carol D.

    2014-01-01

    This article reviews the research and interventions that have grown up around a model of psychological well-being (Ryff, 1989) generated more than two decades ago to address neglected aspects of positive functioning, such as purposeful engagement in life, realization of personal talents and capacities, and enlightened self-knowledge. The conceptual origins of this formulation are revisited and scientific products emerging from six thematic areas are examined: (1) how well-being changes across adult development and later life, (2) what are the personality correlates of well-being, (3) how well-being is linked with experiences in family life, (4) how well-being relates to work and other community activities, (5) what are the connections between well-being and health, including biological risk factors, (6) and via clinical and intervention studies, how psychological well-being can be promoted for ever greater segments of society. Together, these topics illustrate flourishing interest across diverse scientific disciplines in understanding adults as striving, meaning-making, proactive organisms who are actively negotiating the challenges of life. A take-home message is that increasing evidence supports the health protective features of psychological well-being in reducing risk for disease and promoting length of life. A recurrent and increasingly important theme is resilience – the capacity to maintain or regain well-being in the face of adversity. Implications for future research and practice are considered. PMID:24281296

  9. Revisiting reflexology: Concept, evidence, current practice, and practitioner training.

    Science.gov (United States)

    Embong, Nurul Haswani; Soh, Yee Chang; Ming, Long Chiau; Wong, Tin Wui

    2015-10-01

    Reflexology is basically a study of how one part of the human body relates to another part of the body. Reflexology practitioners rely on the reflexes map of the feet and hands to all the internal organs and other human body parts. They believe that by applying the appropriate pressure and massage certain spots on the feet and hands, all other body parts could be energized and rejuvenated. This review aimed to revisit the concept of reflexology and examine its effectiveness, practices, and the training for reflexology practitioners. PubMed, SCOPUS, Google Scholar, and SpringerLink databases were utilized to search the following medical subject headings or keywords: foot massage, reflexology, foot reflexotherapy, reflexological treatment, and zone therapy. The articles published for the last 10 years were included. Previous systematic reviews failed to show concrete evidence for any specific effect of reflexology in any conditions. Due to its non-invasive, non-pharmacological complementary nature, reflexology is widely accepted and anecdotal evidence of positive effect reflexology in a variety of health conditions are available. Adequate training for practitioners is necessary to ensure the consistency of service provided.

  10. Advanced Single-Aisle Transport Propulsion Design Options Revisited

    Science.gov (United States)

    Guynn, Mark D.; Berton, Jeffrey J.; Tong, Michael T.; Haller, William J.

    2013-01-01

    Future propulsion options for advanced single-aisle transports have been investigated in a number of previous studies by the authors. These studies have examined the system level characteristics of aircraft incorporating ultra-high bypass ratio (UHB) turbofans (direct drive and geared) and open rotor engines. During the course of these prior studies, a number of potential refinements and enhancements to the analysis methodology and assumptions were identified. This paper revisits a previously conducted UHB turbofan fan pressure ratio trade study using updated analysis methodology and assumptions. The changes incorporated have decreased the optimum fan pressure ratio for minimum fuel consumption and reduced the engine design trade-offs between minimizing noise and minimizing fuel consumption. Nacelle drag and engine weight are found to be key drivers in determining the optimum fan pressure ratio from a fuel efficiency perspective. The revised noise analysis results in the study aircraft being 2 to 4 EPNdB (cumulative) quieter due to a variety of reasons explained in the paper. With equal core technology assumed, the geared engine architecture is found to be as good as or better than the direct drive architecture for most parameters investigated. However, the engine ultimately selected for a future advanced single-aisle aircraft will depend on factors beyond those considered here.

  11. Background frequencies for residue variability estimates: BLOSUM revisited

    Directory of Open Access Journals (Sweden)

    Reš I

    2007-12-01

    Full Text Available Abstract Background Shannon entropy applied to columns of multiple sequence alignments as a score of residue conservation has proven one of the most fruitful ideas in bioinformatics. This straightforward and intuitively appealing measure clearly shows the regions of a protein under increased evolutionary pressure, highlighting their functional importance. The inability of the column entropy to differentiate between residue types, however, limits its resolution power. Results In this work we suggest generalizing Shannon's expression to a function with similar mathematical properties, that, at the same time, includes observed propensities of residue types to mutate to each other. To do that, we revisit the original construction of BLOSUM matrices, and re-interpret them as mutation probability matrices. These probabilities are then used as background frequencies in the revised residue conservation measure. Conclusion We show that joint entropy with BLOSUM-proportional probabilities as a reference distribution enables detection of protein functional sites comparable in quality to a time-costly maximum-likelihood evolution simulation method (rate4site, and offers greater resolution than the Shannon entropy alone, in particular in the cases when the available sequences are of narrow evolutionary scope.

  12. Single-shot work extraction in quantum thermodynamics revisited

    Science.gov (United States)

    Wang, Shang-Yung

    2018-01-01

    We revisit the problem of work extraction from a system in contact with a heat bath to a work storage system, and the reverse problem of state formation from a thermal system state in single-shot quantum thermodynamics. A physically intuitive and mathematically simple approach using only elementary majorization theory and matrix analysis is developed, and a graphical interpretation of the maximum extractable work, minimum work cost of formation, and corresponding single-shot free energies is presented. This approach provides a bridge between two previous methods based respectively on the concept of thermomajorization and a comparison of subspace dimensions. In addition, a conceptual inconsistency with regard to general work extraction involving transitions between multiple energy levels of the work storage system is clarified and resolved. It is shown that an additional contribution to the maximum extractable work in those general cases should be interpreted not as work extracted from the system, but as heat transferred from the heat bath. Indeed, the additional contribution is an artifact of a work storage system (essentially a suspended ‘weight’ that can be raised or lowered) that does not truly distinguish work from heat. The result calls into question the common concept that a work storage system in quantum thermodynamics is simply the quantum version of a suspended weight in classical thermodynamics.

  13. Reprogramming and the mammalian germline: the Weismann barrier revisited.

    Science.gov (United States)

    Sabour, Davood; Schöler, Hans R

    2012-12-01

    The germline represents a unique cell type that can transmit genetic material to the next generation. During early embryonic development, somatic cells give rise to a small population of cells known as germ cells, which eventually differentiate into mature gametes. Germ cells undergo a process of removing and resetting relevant epigenetic information, mainly by DNA demethylation. This extensive epigenetic reprogramming leads to the conversion of germ cells into immortal cells that can pass on the genome to the next generation. In the absence of germline-specific reprogramming, germ cells would preserve the old, parental epigenetic memory, which would prevent the transfer of heritable information to the offspring. On the contrary, somatic cells cannot reset epigenetic information by preserving the full methylation pattern on imprinting genes. In this review, we focus on the capacity of germ cells and somatic cells (soma) to transfer genetic information to the next generation, and thus revisit the Weismann theory of heredity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Air embolus revisited - a diagnostic and interventional radiological ...

    African Journals Online (AJOL)

    bubble trouble and the dynamic Mercedes Benz sign) ... The article also includes images relating to the depiction of air embolus, with attention drawn to a commonly encountered imaging appearance or sign. South African Journal of Radiology ...

  15. Revisiting Individual Creativity Assessment: Triangulation in Subjective and Objective Assessment Methods

    Science.gov (United States)

    Park, Namgyoo K.; Chun, Monica Youngshin; Lee, Jinju

    2016-01-01

    Compared to the significant development of creativity studies, individual creativity research has not reached a meaningful consensus regarding the most valid and reliable method for assessing individual creativity. This study revisited 2 of the most popular methods for assessing individual creativity: subjective and objective methods. This study…

  16. Revisiting "The Widget Effect": Teacher Evaluation Reforms and the Distribution of Teacher Effectiveness

    Science.gov (United States)

    Kraft, Matthew A.; Gilmour, Allison F.

    2017-01-01

    In 2009, the New Teacher Project's "The Widget Effect" documented the failure of U.S. public school districts to recognize and act on differences in teacher effectiveness. We revisit these findings by compiling teacher performance ratings across 24 states that adopted major reforms to their teacher evaluation systems. In the vast…

  17. Revisiting Interpretation of Canonical Correlation Analysis: A Tutorial and Demonstration of Canonical Commonality Analysis

    Science.gov (United States)

    Nimon, Kim; Henson, Robin K.; Gates, Michael S.

    2010-01-01

    In the face of multicollinearity, researchers face challenges interpreting canonical correlation analysis (CCA) results. Although standardized function and structure coefficients provide insight into the canonical variates produced, they fall short when researchers want to fully report canonical effects. This article revisits the interpretation of…

  18. The metric theory of tensor products (grthendieck's résumé revisited ...

    African Journals Online (AJOL)

    The metric theory of tensor products (grthendieck's résumé revisited) part 2: Bilinear forms and linear operators of type α. ... Mathematics Subject Classification (2000): 46B28, 46B07, 46B10. Key words: α-forms;α-integral operators; (metric) accessibility; α-nuclear forms (operators). Quaestiones Mathematicae 25 (2002), 73- ...

  19. The Best and the Rest: Revisiting the Norm of Normality of Individual Performance

    Science.gov (United States)

    O'Boyle, Ernest, Jr.; Aguinis, Herman

    2012-01-01

    We revisit a long-held assumption in human resource management, organizational behavior, and industrial and organizational psychology that individual performance follows a Gaussian (normal) distribution. We conducted 5 studies involving 198 samples including 633,263 researchers, entertainers, politicians, and amateur and professional athletes.…

  20. Revisiting Evidence for Modularity and Functional Equivalence across Verbal and Spatial Domains in Memory

    Science.gov (United States)

    Guerard, Katherine; Tremblay, Sebastien

    2008-01-01

    The authors revisited evidence in favor of modularity and of functional equivalence between the processing of verbal and spatial information in short-term memory. This was done by investigating the patterns of intrusions, omissions, transpositions, and fill-ins in verbal and spatial serial recall and order reconstruction tasks under control,…

  1. My First CMC Article Revisited: A Window on Spanish L2 Interlanguage

    Science.gov (United States)

    Blake, Robert

    2016-01-01

    The computer-assisted language learning (CALL) field seems to change overnight with new technological affordances. Blake revisits his 2000 "LLT" article on computer-mediation communication (CMC) in order to reflect on how the field has examined this topic over the past decade or so. While the Interaction Hypothesis continues to guide…

  2. Trade Unions, immigration and immigrants in Europe revisited: Unions’ attitudes and actions under new conditions

    NARCIS (Netherlands)

    Marino, S.; Penninx, R.; Roosblad, J.

    2015-01-01

    This paper revisits the comparative approach used by Penninx and Roosblad (Trade Unions, Immigration and Immigrants in Europe, 1960-1993. New York: Berghahn Books) to study trade unions’ attitudes and actions in relation to immigrant workers in seven Western European countries. It reassesses that

  3. Considerations of the Social, Individual, and Embodied: A Response to Comments on "Schema Theory Revisited"

    Science.gov (United States)

    McVee, Mary B.; Gavelek, James R.; Dunsmore, Kailonnie L.

    2007-01-01

    This article presents the authors' response and clarifications to the comments of Margaret E. Gredler and of Karen A. Krasny, Mark Sadoski, and Allan Paivio on their article "Schema Theory Revisited." The authors first respond to Gredler's criticism contending that they "transmogrified" Harre's (1984) "ignominiously named...Vygotsky space" in…

  4. Re-Visit to the School Nurse and Adolescents' Medicine Use

    Science.gov (United States)

    Borup, Ina K.; Andersen, Anette; Holstein, Bjorn E.

    2011-01-01

    Objective: To examine if students who re-visit the school nurse use medicines differently than other students when exposed to aches and psychological problems. Methods: The study includes all 11-, 13- and 15-year-old students from a random sample of schools in Denmark, response rate 87 per cent, n = 5,205. The data collection followed the…

  5. DNA as Genetic Material: Revisiting Classic Experiments through a Simple, Practical Class

    Science.gov (United States)

    Malago, Wilson, Jr.; Soares-Costa, Andrea; Henrique-Silva, Flavio

    2009-01-01

    In 1928, Frederick Griffith demonstrated a transmission process of genetic information by transforming "Pneumococcus". In 1944, Avery et al. demonstrated that Griffith's transforming principle was DNA. We revisited these classic experiments in a practical class for undergraduate students. Both experiments were reproduced in simple, adapted forms.…

  6. Paleosol at the Archean–Proterozoic contact in NW India revisited ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 117; Issue 3. Paleosol at the Archean–Proterozoic contact in NW India revisited – Evidence for oxidizing conditions during paleo-weathering? Manoj K Pandit Helga de Wall Narendra K Chauhan. Volume 117 Issue 3 June 2008 pp 201-209 ...

  7. Hell revisited: A socio-critical enquiry into the roots and relevance of ...

    African Journals Online (AJOL)

    p1243322

    “Hell revisited: A socio-critical enquiry into the roots and relevance of hell for the church today”, in the ... leaders (Van Holten 2003:457). One rarely hears ..... So this theory contends that all will not be saved, but neither will any be in conscious torment forever – God resurrects the wicked to judge them, after which they are.

  8. The solution of an open XXZ chain with arbitrary spin revisited

    OpenAIRE

    Murgan, Rajan; Silverthorn, Christopher

    2014-01-01

    The Bethe ansatz solutions for an open XXZ spin chain with arbitrary spin with N sites and nondiagonal boundary terms are revisited. The anisotropy parameter, for cases considered here, has values \\eta = i \\pi r/q, where r and q are positive integers with q restricted to odd integers. Numerical results are presented to support the solutions.

  9. “Be active!” Revisiting the South African food-based dietary ...

    African Journals Online (AJOL)

    “Be active!” Revisiting the South African food-based dietary guideline for activity. CR Botha, SJ Moss, TL Kolbe-Alexander. Abstract. The objective of this paper was to review current evidence on physical activity for health in order to support the foodbased dietary guideline (FBDG) “Be active!”. Physical activity, defined as at ...

  10. Strong and weak family ties revisited: reconsidering European family structures from a network perspective.

    NARCIS (Netherlands)

    Mönkediek, B.; Bras, H.

    2014-01-01

    Family systems appear to be an important factor framing people's individual behavior. Thus far, family systems have been primarily addressed on a macro regional level with indirect measures. Revisiting Reher (1998) and the family ties criterion, the main question of this paper is to examine to what

  11. Service-Learning in Crisis Communication Education: Revisiting Coombs' Objectives for the Crisis Communication Course

    Science.gov (United States)

    Maresh-Fuehrer, Michelle M.

    2015-01-01

    The purpose of this study was to revisit Coombs' suggestions for teaching the crisis communication course using service-learning as a framework. The author sought to assess the effectiveness of using this method in terms of the benefits to both students and the partnering organization and students' perceptions of whether they met the learning…

  12. A revisit of the mode of interaction of small transcription inhibitors ...

    Indian Academy of Sciences (India)

    A revisit of the mode of interaction of small transcription inhibitors with genomic DNA. Dipak Dasgupta Parijat ... the associated histone(s). Structural effects of the DNA-binding molecules upon chromatin in light of the above broad categories and the associated biological implications of the two types of binding are discussed.

  13. Revisiting the Gun Ownership and Violence Link; a multi- level analysis of victimisation survey data.

    NARCIS (Netherlands)

    van Kesteren, J.N.

    2014-01-01

    The link between gun ownership victimisation by violent crime remains one of the most contested issues in criminology. Some authors claim that high gun availability facilitates serious violence. Others claim that gun ownership prevents crime. This article revisits these issues using individual and

  14. Hypothermic machine preservation in liver transplantation revisited : Concepts and criteria in the new millennium

    NARCIS (Netherlands)

    van der Plaats, A; t'Hart, NA; Verkerke, GJ; Leuvenink, HGD; Ploeg, RJ; Rakhorst, G

    To overcome the present shortage of liver donors by expansion of the existing donor pool and possibly lengthening of the storage time, hypothermic machine perfusion of the liver as a dynamic preservation method is revisited. The three most important aspects are defined to be the type of preservation

  15. Understanding Emergency Department 72-Hour Revisits Among Medicaid Patients Using Electronic Healthcare Records.

    Science.gov (United States)

    Ryan, James; Hendler, James; Bennett, Kristin P

    2015-12-01

    Electronic Healthcare Records (EHRs) have the potential to improve healthcare quality and to decrease costs by providing quality metrics, discovering actionable insights, and supporting decision-making to improve future outcomes. Within the United States Medicaid Program, rates of recidivism among emergency department (ED) patients serve as metrics of hospital performance that help ensure efficient and effective treatment within the ED. We analyze ED Medicaid patient data from 1,149,738 EHRs provided by a hospital over a 2-year period to understand the characteristics of the ED return visits within a 72-hour time frame. Frequent flyer patients with multiple revisits account for 47% of Medicaid patient revisits over this period. ED encounters by frequent flyer patients with prior 72-hour revisits in the last 6 months are thrice more likely to result in a readmit than those of infrequent patients. Statistical L1-logistic regression and random forest analyses reveal distinct patterns of ED usage and patient diagnoses between frequent and infrequent patient encounters, suggesting distinct opportunities for interventions to improve efficacy of care and streamline ED workflow. This work forms a foundation for future development of predictive models, which could flag patients at high risk of revisiting.

  16. “Be active!” Revisiting the South African food-based dietary ...

    African Journals Online (AJOL)

    2013-04-08

    Apr 8, 2013 ... “Be active!” Revisiting the South African food-based dietary guideline for activity. Botha CR, PhD, BSc, HMS, Senior Lecturer; Wright HH, PhD, Senior Lecturer. Centre of Excellence for Nutrition, North-West University. Moss SJ, PhD, MSc, BSc, HMS, MBA, Professor, Physical Activity, Sport and Recreation, ...

  17. The Myth of Meeting Needs Revisited: The Case of Educational Research

    Science.gov (United States)

    Lawy, Robert; Armstrong, Paul

    2009-01-01

    Our primary objective in this paper is revisit a debate that was articulated 25 years ago in this journal in which it was argued that the idea of meeting needs in adult and continuing education is a myth. We extend the original analysis of need and apply it to the case of educational research. We look at the policy context, which has, in the…

  18. Teacher Communication Concerns Revisited: Calling into Question the Gnawing Pull towards Equilibrium

    Science.gov (United States)

    Dannels, Deanna P.

    2015-01-01

    This study revisits the long-standing teacher communication concerns framework originating over three decades ago. Analysis of 10 years of contemporary GTA teacher communication concerns reveals a typology of 10 concerns, which taken together construct teaching as a process of negotiating relationships, managing identities, and focusing attention.…

  19. The Peter Effect Revisited: Reading Habits and Attitudes of College Students

    Science.gov (United States)

    Applegate, Anthony J.; Applegate, Mary DeKonty; Mercantini, Martha A.; McGeehan, Catherine M.; Cobb, Jeanne B.; DeBoy, Joanne R.; Modla, Virginia B.; Lewinski, Kimberly E.

    2014-01-01

    Certainly a primary goal of literacy education is the creation of avid, enthusiastic, and highly motivated readers. However, in this article revisiting the Peter Effect (Applegate & Applegate, 2004), researchers surveyed more than 1,000 college sophomores and found strikingly low levels of enthusiasm for reading. Only 46.6% of surveyed…

  20. The skeptical green consumer revisited: testing the relationship between green consumerism and skepticism toward advertising

    NARCIS (Netherlands)

    Matthes, J.; Wonneberger, A.

    2014-01-01

    This article revisits the widely believed notion of the skeptical green consumer, in other words, that green consumers tend to distrust green advertising. Study 1, a survey of U.S. consumers, found no positive relationship between green consumerism and general ad skepticism. However, green

  1. Revisiting First-Year College Students' Mattering: Social Support, Academic Stress, and the Mattering Experience

    Science.gov (United States)

    Rayle, Andrea Dixon; Chung, Kuo-Yi

    2008-01-01

    In this study, Nancy Schlossberg's (1989) theory of college students' mattering to others was revisited. Mattering is the experience of others depending on us, being interested in us, and being concerned with our fate. The relationships of gender, mattering to college friends and the college environment, and friend and family social support with…

  2. Imaging Hindered Rotations of Alkoxy Species on TiO2(110)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhenrong; Rousseau, Roger J.; Gong, Jinlong; Kay, Bruce D.; Dohnalek, Zdenek

    2009-12-16

    We present the first study of the rotational dynamics of organic species on any oxide surface. Specifically, variable-temperature scanning tunneling microscopy (STM) and dispersion-corrected density functional theory are used to study the alkyl chain conformational disorder and dynamics of 1-, 2-, 3- and 4-octoxy on rutile TiO2(110). Initially, the geminate pairs of the octoxy and bridging hydroxyl species are created via octanol dissociation on bridging-oxygen (Ob) vacancy defects. The STM images provide time averaged snapshots of octoxy species rotating among multiple energetically nearly-degenerate configurations accessible at a given temperature. In the calculations we find that the underlying corrugated potential energy surface is a result of the interplay between attractive Van der Waals dispersion forces leading to weak attractive C...Ti and repulsive C...Ob interactions which lead to large barriers of 50-70kJmol-1 for the rotation of the octoxy alkyl chains across the Ob rows. In the presence of the germinal hydroxyl groups we find that the relative populations of the various conformations as well as the rotational barriers are perturbed by the presence of geminate hydroxyl due to additional C...hydroxyl repulsions.

  3. DMPD: TLR signalling and activation of IRFs: revisiting old friends from the NF-kappaBpathway. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16006187 TLR signalling and activation of IRFs: revisiting old friends from the NF-...kappaBpathway. Moynagh PN. Trends Immunol. 2005 Sep;26(9):469-76. (.png) (.svg) (.html) (.csml) Show TLR signalling and activation... of IRFs: revisiting old friends from the NF-kappaBpathway. PubmedID 16006187 Title TLR signalling and activati...on of IRFs: revisiting old friends from the NF-kappaBpat

  4. Ecological caring-Revisiting the original ideas of caring science.

    Science.gov (United States)

    Dahlberg, Helena; Ranheim, Albertine; Dahlberg, Karin

    2016-01-01

    The aim of this empirically grounded philosophical paper is to explore the notion of holistic care with the intention to expand it into a notion of ecological care and in such a way revisit the original ideas of caring science. The philosophical analysis, driven by lifeworld theory and especially Merleau-Ponty's philosophy, is firmly rooted in contemporary clinical care. We used interview data from patients in a study at an anthroposophic clinic in Sweden, which forms part of an ecological community with, for example, ecological agriculture. The empirical study is analysed according to reflective lifeworld research. Starting from the fact that illness can be defined as a loss of homelikeness in the body and in the familiar world, our findings illustrate how ecological care helps the patient to once again find one's place in a world that is characterized by interconnectedness. The task of ecological care is thus not only to see the patient within a world of relationships but to help the patient find his/her place again, to understand himself/herself and the world anew . Ecological care is not only about fighting an illness, but also recognizes a patient from inside a world that s/he is affected by and affects, that s/he is understood and understands from. Such care tries to restore this connection by making possible the rhythmical movement as well as the space in-between activity and rest, between being cared for and actively involving oneself in one's recovery and between closing oneself off from the world and once again going out into it.

  5. Ecological caring—Revisiting the original ideas of caring science

    Science.gov (United States)

    Dahlberg, Helena; Ranheim, Albertine; Dahlberg, Karin

    2016-01-01

    The aim of this empirically grounded philosophical paper is to explore the notion of holistic care with the intention to expand it into a notion of ecological care and in such a way revisit the original ideas of caring science. The philosophical analysis, driven by lifeworld theory and especially Merleau-Ponty's philosophy, is firmly rooted in contemporary clinical care. We used interview data from patients in a study at an anthroposophic clinic in Sweden, which forms part of an ecological community with, for example, ecological agriculture. The empirical study is analysed according to reflective lifeworld research. Starting from the fact that illness can be defined as a loss of homelikeness in the body and in the familiar world, our findings illustrate how ecological care helps the patient to once again find one's place in a world that is characterized by interconnectedness. The task of ecological care is thus not only to see the patient within a world of relationships but to help the patient find his/her place again, to understand himself/herself and the world anew. Ecological care is not only about fighting an illness, but also recognizes a patient from inside a world that s/he is affected by and affects, that s/he is understood and understands from. Such care tries to restore this connection by making possible the rhythmical movement as well as the space in-between activity and rest, between being cared for and actively involving oneself in one's recovery and between closing oneself off from the world and once again going out into it. PMID:27914196

  6. Revisiting the sequencing of the first tree genome: Populus trichocarpa.

    Science.gov (United States)

    Wullschleger, Stan D; Weston, D J; DiFazio, S P; Tuskan, G A

    2013-04-01

    Ten years ago, it was announced that the Joint Genome Institute with funds provided by the Department of Energy, Office of Science, Biological and Environmental Research would sequence the black cottonwood (Populus trichocarpa Torr. & Gray) genome. This landmark decision was the culmination of work by the forest science community to develop Populus as a model system. Since its public release in late 2006, the availability of the Populus genome has spawned research in plant biology, morphology, genetics and ecology. Here we address how the tree physiologist has used this resource. More specifically, we revisit our earlier contention that the rewards of sequencing the Populus genome would depend on how quickly scientists working with woody perennials could adopt molecular approaches to investigate the mechanistic underpinnings of basic physiological processes. Several examples illustrate the integration of functional and comparative genomics into the forest sciences, especially in areas that target improved understanding of the developmental differences between woody perennials and herbaceous annuals (e.g., phase transitions). Sequencing the Populus genome and the availability of genetic and genomic resources has also been instrumental in identifying candidate genes that underlie physiological and morphological traits of interest. Genome-enabled research has advanced our understanding of how phenotype and genotype are related and provided insights into the genetic mechanisms whereby woody perennials adapt to environmental stress. In the future, we anticipate that low-cost, high-throughput sequencing will continue to facilitate research in tree physiology and enhance our understanding at scales of individual organisms and populations. A challenge remains, however, as to how genomic resources, including the Populus genome, can be used to understand ecosystem function. Although examples are limited, progress in this area is encouraging and will undoubtedly improve as

  7. Memory Revisited in Julian Barnes's The Sense of an Ending

    Directory of Open Access Journals (Sweden)

    Maricel Oró Piqueras

    2014-02-01

    Full Text Available An accumulation of years brings with it an accumulation of experiences. The revision of such experiences usually becomes more recurrent after retirement, a transition time from one period of life to another and, as such, a time in which we, human beings, have a tendency to take stock of our lives. This is actually one of the main issues present in Julian Barnes's last novel The Sense of an Ending (2011. When the main protagonist, a retired man quite comfortable and contented with his present life, receives an unexpected inheritance from the mother of a girlfriend from his university years, he is forced to track down a part of his life that he had left at the back of his mind a long time ago. As he explains his story, the protagonist and narrator of the novel raises a number of questions related to the quality and function of memory as one gets into old age. He experiments the unreliability of memory and questions to what extent memory is constructed through the remembered emotions that invaded him over that episode of his life rather than through the events as they actually took place. On the other hand, the act of revisiting and revising that specific episode, brings with it feelings of guilt and remorse as the protagonist realises that his past acts were not as noble as he remembered them to be. However, these acts are part of the past and they cannot be changed; thus, another question that the novel raises is how to account for those actions of which one does not feel proud and, more importantly, how to manage those bad memories as one gets older

  8. Practical Considerations for Perforator Flap Thinning Procedures Revisited

    Directory of Open Access Journals (Sweden)

    Theddeus OH Prasetyono

    2014-11-01

    Full Text Available BackgroundA thin perforator flap is one of the best methods for covering defects. This study aimed to revisit and further test the rapidly advancing field of flap thinning techniques.MethodsWe performed two cadaveric studies to test the known flap thinning methods, and then applied these methods to a clinical series. In the first study, five cadavers were used to observe the anatomical relation of the perforator with the subdermal plexuses and the subcutaneous fat layer by injecting a colored latex solution. The second study was done on four cadavers independently from the first study. Last, a clinical series was performed on 15 patients.ResultsThe areolar fat lobules of 10 anterolateral thigh perforator (ALT, seven deep inferior epigastric artery perforator (DIEAP, and six thoracodorsal artery perforator (TAP flaps were dissected to reduce the flap thickness guided by the colored vascular pattern. On average, the ALT, DIEAP, and TAP flaps were reduced to 32.76%±9.76%, 37.01%±9.21%, and 35.42%±9.41%, respectively. In the second study, the areolar fat lobules were directly dissected in six ALT, six TAP, and four MSAP flaps, and an average reduction in flap thickness of 53.41%±5.64%, 52.30%±2.88%, and 47.87%±6.41%, respectively, was found. In the clinical series, 13 out of the 15 cases yielded satisfactory outcomes with an average thickness reduction of 37.91%±7.15%.ConclusionsThese multiple studies showed that the deep fat layer could be safely removed to obtain a thin yet viable perforator flap. This evidence suggests that the macroscopic flap thinning technique can achieve thin flaps. Surgeons should consider this technique before embracing the latest technique of supermicrosurgery.

  9. "Research on Infertility: Definition Makes a Difference" Revisited.

    Science.gov (United States)

    Jacobson, Melanie H; Chin, Helen B; Mertens, Ann C; Spencer, Jessica B; Fothergill, Amy; Howards, Penelope P

    2018-02-01

    In a 1989 paper, Marchbanks et al. (Am J Epidemiol. 1989;130(2):259-267) noted inconsistent definitions of infertility across research and clinical practice and examined differences in prevalence estimates across definitions. Since their study, there have been substantial changes in society, technology, and clinical practice related to female reproductive health. In response, we revisited the original paper using data from a recent study among reproductive-aged women. Internal comparisons across various definitions of infertility were made by assessing how many and which women were classified as infertile, their age at infertility, and the probability of spontaneous pregnancy after infertility. Results were also compared with Marchbanks et al. Black women were more likely to be classified as infertile than white women based on the definition "12 months of unprotected intercourse" (40.1% vs. 33.7%) but less likely by "12 months of attempting pregnancy" (14.3% vs. 21.8%) and "visiting a doctor for help getting pregnant" (8.4% vs. 19.7%). After unprotected intercourse for 12 months, 36.1% of women who were attempting pregnancy spontaneously conceived by 6 months compared with 13.5% of women who were not attempting pregnancy. While our results for most infertility definitions were similar to those of Marchbanks et al., prevalence estimates continued to differ across demographic groups by definition. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Guarana: revisiting a highly caffeinated plant from the Amazon.

    Science.gov (United States)

    Schimpl, Flávia Camila; da Silva, José Ferreira; Gonçalves, José Francisco de Carvalho; Mazzafera, Paulo

    2013-10-28

    Guarana (Paullinia cupana Kunth var. sorbilis (Mart.) Ducke) has been traditionally consumed by indigenous communities of the Amazon region. It is valued mainly for its stimulant property because of its high content of caffeine, which can be up to 6% in the seeds. The purpose of this review is to revisit this typically Brazilian plant, addressing economic considerations, the chemical makeup of the seeds and pharmacological properties so far investigated. Guarana is primarily produced in the Brazilian states of Amazonas and Bahia, and approximately 70% of the production is used by the industry of soft and energy drinks. The other 30% becomes guarana powder for direct consumption in capsules or dilution in water, or it serves as a raw material for the pharmaceutical and cosmetics industries. In addition to its stimulant property, guarana has other therapeutic properties, which have aroused the interest of the scientific community. This review shows that other guarana properties may be explored and how scarce are the studies regarding agronomic, plant pathology, physiology and breeding. So far, caffeine has been the main reason to study guarana and still will lead the researches because the demand for this alkaloid by food and pharmaceutical industry, and a strongly growing market related with beauty products. However, guarana has other components and there is great interest in studies designed to elucidate the effects of guarana's bioactive components and their potential pharmacological applications. Significant part of the guarana production in Brazil still comes from Indians tribes in the Amazon State, and any improvement in this plant, in any aspect, may propitiate a positive economic impact in their lives. © 2013 Elsevier Ireland Ltd. All rights reserved.

  11. The Benevolent Leader Revisited: Children's Images of Political Leaders in Three Democracies

    Science.gov (United States)

    Greenstein, Fred I.

    1975-01-01

    Describes 10- to 14-year old children's responses to open-ended questions about political leaders in Britain, France, and United States in light of political socialization literature. For journal availability see SO 504 327. (ND)

  12. Revisiting Age-of-Acquisition Effects in Spanish Visual Word Recognition: The Role of Item Imageability

    Science.gov (United States)

    Wilson, Maximiliano A.; Cuetos, Fernando; Davies, Rob; Burani, Cristina

    2013-01-01

    Word age-of-acquisition (AoA) affects reading. The mapping hypothesis predicts AoA effects when input--output mappings are arbitrary. In Spanish, the orthography-to-phonology mappings required for word naming are consistent; therefore, no AoA effects are expected. Nevertheless, AoA effects have been found, motivating the present investigation of…

  13. Designing and implementing a PACS-aware DICOM image object for digital x-ray, mammography, and intraoral applications

    Science.gov (United States)

    Clunie, David A.

    1999-07-01

    The introduction of new digital detector technology for projection radiography created an opportunity to revisit the support for x-ray images in the DICOM standard. A new family of digital x-ray objects has been developed with greater emphasis on the productivity and workflow requirements of PACS and soft copy reading on workstations. The use of these DX objects present new design challenges for acquisition and display systems.

  14. Body Image

    Science.gov (United States)

    ... Blog About Us Contact Us Text size | Print | Body Image Developing a positive body image and a healthy mental attitude is crucial ... Read on for tips to have a healthy body image. Â Topics About body image When you ...

  15. Speculations on the Origin of STM

    Directory of Open Access Journals (Sweden)

    Joachim Hoffmann

    2010-10-01

    Full Text Available Memory generally is understood as being “a system for storing and retrieving information” (e.g. Baddeley, 1997, p.9. Accordingly, memory has been investigated almost exclusively by presenting some stimulus materials to the participants, such as a list of words or a series of pictures, and by testing the ability of the participants to retrieve the stimuli after some time. However, memory is more than the ability to reproduce earlier presented word lists or to recognize earlier presented pictures. In some sense memory is involved in any activity we perform. Already perceiving is in essence recognition. When we see a birch, the visual stimulus activates what we know about birches: how they look like, the features they possess, and how they are called. Likewise, acting is also in essence recall. When we sign a document, we have to recall how to move our hand in order to produce the signature; the same is true for walking, speaking, and every other activity we are familiar with. We always have to reproduce what to do in order to attain the intended goal. Under this broader perspective, memory not only refers to storing and retrieving information but to the preservation of experiences in general. In other words, memory underlies aftereffects of current experiences on future behaviour. This general description resembles very much the definition typically used for learning. Thus, it appears that learning and memory are not distinct processes but rather two different sides of one and the same coin.

  16. PENDEKATAN SAINS TEKNOLOGI MASYARAKAT (STM DALAM PEMBELAJARAN

    Directory of Open Access Journals (Sweden)

    Roni Faslah

    2013-08-01

    Full Text Available Influences of globalization are getting felt together with the increasing of variety kinds of information providers in the form of press released or unreleased, broadcast or not broadcast, electronic or not electronic information providers, such as, newspaper, magazine, radio television, facsimiles, computer, internet, communication satellite. Improvement of technology of communication and information inclined to influence the condition of social aspect, economic aspect, culture, and also the condition of education. The applications of communication and information are giving the possibility to create global learning condition which is connected to the link that put students in the central of learning process and surrounded by many kinds of electronic learning source. Base on all of that, conventional education should be softer by accepting new style of learning which is completed by improved technology. We really need human beings, who can get along with the improvement of technology, who have knowledge of tools, source and process where knowledge is put as the central of the soul, comprehended and used in their live to increase the quality of work in the purpose of getting better prosperity in their life. The elements of human which are improved in the aspect of technology are power of thinking, power of heart, and physical power.

  17. STM investigation on single, physisorbed dendrimers

    NARCIS (Netherlands)

    Merz, L.; Hitz, J.; Hubler, U.; Weyermann, P.; Diederich, F.; Murer, P.; Seebach, D.; Widmer, I.; Stöhr, Meike; Güntherodt, H.-J.; Hermann, B.A.

    2002-01-01

    Porphyrin dendrimers were synthesized to mimic naturally occurring proteins, which catalyze a number of biochemically important reactions. In addition, chiral dendrimers were prepared as model compounds for the study of nanoscopic chirality. The structures of these dendrimers cannot be characterized

  18. Mucoid Degeneration of the Anterior Cruciate Ligament: Magnetic Resonance Imaging Findings of an Underdiagnosed Entity

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, J.L.; Viana, S.L.; Mendonca, J.L.F.; Freitas, F.M.O.; Bezerra, A.S.A.; Lima, G.A.S.; Matos, V.L.; Cunha, N.F.; Martins, R.R.; Freitas, R.M.O. (Magnetic Resonance Dept., Clinica Radiologica Vila Rica, Brasilia (Brazil))

    2008-02-15

    Although imaging and clinical criteria are already established for the diagnosis of mucoid degeneration of the anterior cruciate ligament (ACL), many radiologists remain unaware of their existence. Once regarded as a rare occurrence, it has been recently suggested that its incidence is in fact very much higher than previously thought, and that it is probably underdiagnosed or misdiagnosed as partial ruptures of the ACL or as cystic ganglia. In this review, the authors revisit the literature concerning this subject and present their personal experience with it, stressing the paramount importance of magnetic resonance imaging and correlation with clinical data for a correct diagnosis

  19. Diffusion Monte Carlo Study of Para-Diiodobenzene Polymorphism Revisited.

    Science.gov (United States)

    Hongo, Kenta; Watson, Mark A; Iitaka, Toshiaki; Aspuru-Guzik, Alán; Maezono, Ryo

    2015-03-10

    We revisit our investigation of the diffusion Monte Carlo (DMC) simulation of para-diiodobenzene (p-DIB) molecular crystal polymorphism. [See J. Phys. Chem. Lett. 2010, 1, 1789-1794.] We perform, for the first time, a rigorous study of finite-size effects and choice of nodal surface on the prediction of polymorph stability in molecular crystals using fixed-node DMC. Our calculations are the largest that are currently feasible using the resources of the K-computer and provide insights into the formidable challenge of predicting such properties from first principles. In particular, we show that finite-size effects can influence the trial nodal surface of a small (1 × 1 × 1) simulation cell considerably. Therefore, we repeated our DMC simulations with a 1 × 3 × 3 simulation cell, which is the largest such calculation to date. We used a density functional theory (DFT) nodal surface generated with the PBE functional, and we accumulated statistical samples with ∼6.4 × 10(5) core hours for each polymorph. Our final results predict a polymorph stability that is consistent with experiment, but they also indicate that the results in our previous paper were somewhat fortuitous. We analyze the finite-size errors using model periodic Coulomb (MPC) interactions and kinetic energy corrections, according to the CCMH scheme of Chiesa, Ceperley, Martin, and Holzmann. We investigate the dependence of the finite-size errors on different aspect ratios of the simulation cell (k-mesh convergence) in order to understand how to choose an appropriate ratio for the DMC calculations. Even in the most expensive simulations currently possible, we show that the finite size errors in the DMC total energies are much larger than the energy difference between the two polymorphs, although error cancellation means that the polymorph prediction is accurate. Finally, we found that the T-move scheme is essential for these massive DMC simulations in order to circumvent population explosions and

  20. Recycling Revisited: Where did all the Subducted Sediments go?

    Science.gov (United States)

    Hofmann, A. W.; Chauvel, C.; Lewin, E.; Kelemen, P. B.; Hacker, B. R.

    2016-12-01

    Several lines of reasoning have revived the idea [1] that subduction has recycled continent-derived sediments into the mantle on a massive scale. For example, well-known peaks in zircon ages have been reinterpreted as reflecting variable rates of crust destruction via erosion and sediment subduction [2]. In addition, assessment of the trace element budgets of subducted sediments and arc volcanics, as well as geological and geophysical studies of accretionary wedges have led to estimates that about one mass of present-day continental crust has been returned to the mantle [3]. If these ideas are correct, then recycled sedimentary components should be present in MORB and OIB sources. As previously established, Nb/U and 87Sr/86Sr are negatively correlated in all EM2-type OIBs, clearly indicating continental/sedimentary input. However, the MORB source reservoir, being depleted in incompatible elements, is particularly susceptible to "pollution" by subducted sediments. Chauvel et al. [4] modeled the Hf-Nd isotopic array of MORBs+OIBs and concluded that it requires the addition of up to 6 % subducted sediment. We revisit this issue and show that global MORBs show no decrease in Nb/U with increasing 87Sr/86Sr, ruling out extensive addition of recycled sediment into global MORB sources. Instead, the Hf-Nd array can be obtained by recycled alkali basalts derived from subducted seamounts and ocean islands, rather than sediments. Moreover, mantle plumes with clearly identifiable sediment input contribute less than 20% of the total plume flux. We conclude that most of the subducted sediment flux is not returned to the convecting mantle. Instead, its most plausible fate is to be underplated beneath existing continental crust via "relamination" [5]. These results imply that continental recycling is subordinate and the growth of the continental crust has been largely irreversible. [1] Armstrong, 1968, Rev. Geophys. 6, 175. [2] Hawkesworth et al., 2009, Science 323, 49. [3] Porter

  1. Revisiting Scaling Relations for Giant Radio Halos in Galaxy Clusters

    Science.gov (United States)

    Cassano, R.; Ettori, S.; Brunetti, G.; Giacintucci, S.; Pratt, G. W.; Venturi, T.; Kale, R.; Dolag, K.; Markevitch, Maxim L.

    2013-01-01

    Many galaxy clusters host megaparsec-scale radio halos, generated by ultrarelativistic electrons in the magnetized intracluster medium. Correlations between the synchrotron power of radio halos and the thermal properties of the hosting clusters were established in the last decade, including the connection between the presence of a halo and cluster mergers. The X-ray luminosity and redshift-limited Extended GMRT Radio Halo Survey provides a rich and unique dataset for statistical studies of the halos. We uniformly analyze the radio and X-ray data for the GMRT cluster sample, and use the new Planck Sunyaev-Zel'dovich (SZ) catalog to revisit the correlations between the power of radio halos and the thermal properties of galaxy clusters. We find that the radio power at 1.4 GHz scales with the cluster X-ray (0.1-2.4 keV) luminosity computed within R(sub 500) as P(sub 1.4) approx. L(2.1+/-0.2) - 500). Our bigger and more homogenous sample confirms that the X-ray luminous (L(sub 500) > 5 × 10(exp 44) erg/s)) clusters branch into two populations-radio halos lie on the correlation, while clusters without radio halos have their radio upper limits well below that correlation. This bimodality remains if we excise cool cores from the X-ray luminosities. We also find that P(sub 1.4) scales with the cluster integrated SZ signal within R(sub 500), measured by Planck, as P(sub 1.4) approx. Y(2.05+/-0.28) - 500), in line with previous findings. However, contrary to previous studies that were limited by incompleteness and small sample size, we find that "SZ-luminous" Y(sub 500) > 6×10(exp -5) Mpc(exp 2) clusters show a bimodal behavior for the presence of radio halos, similar to that in the radio-X-ray diagram. Bimodality of both correlations can be traced to clusters dynamics, with radio halos found exclusively in merging clusters. These results confirm the key role of mergers for the origin of giant radio halos, suggesting that they trigger the relativistic particle acceleration.

  2. Facial clefts and facial dysplasia: revisiting the classification.

    Science.gov (United States)

    Mazzola, Riccardo F; Mazzola, Isabella C

    2014-01-01

    Most craniofacial malformations are identified by their appearance. The majority of the classification systems are mainly clinical or anatomical, not related to the different levels of development of the malformation, and underlying pathology is usually not taken into consideration. In 1976, Tessier first emphasized the relationship between soft tissues and the underlying bone stating that "a fissure of the soft tissue corresponds, as a general rule, with a cleft of the bony structure". He introduced a cleft numbering system around the orbit from 0 to 14 depending on its relationship to the zero line (ie, the vertical midline cleft of the face). The classification, easy to understand, became widely accepted because the recording of the malformations was simple and communication between observers facilitated. It represented a great breakthrough in identifying craniofacial malformations, named clefts by him. In the present paper, the embryological-based classification of craniofacial malformations, proposed in 1983 and in 1990 by us, has been revisited. Its aim was to clarify some unanswered questions regarding apparently atypical or bizarre anomalies and to establish as much as possible the moment when this event occurred. In our opinion, this classification system may well integrate the one proposed by Tessier and tries at the same time to find a correlation between clinical observation and morphogenesis.Terminology is important. The overused term cleft should be reserved to true clefts only, developed from disturbances in the union of the embryonic facial processes, between the lateronasal and maxillary process (or oro-naso-ocular cleft); between the medionasal and maxillary process (or cleft of the lip); between the maxillary processes (or cleft of the palate); and between the maxillary and mandibular process (or macrostomia).For the other types of defects, derived from alteration of bone production centers, the word dysplasia should be used instead. Facial

  3. Mountain Wave-Induced Turbulence - "Lower Turbulent Zones" Revisited

    Science.gov (United States)

    Strauss, Lukas; Grubišić, Vanda; Serafin, Stefano; Mühlgassner, Rita

    2014-05-01

    In their seminal 1974 paper on "Lower Turbulent Zones Associated with Mountain Lee Waves" P. F. Lester and W. A. Fingerhut attempted to characterize regions of low-level turbulence in the lee of mountain ranges that are commonly associated with large-amplitude mountain waves aloft. For their study, they made extensive use of airborne measurements with small research aircraft that penetrated into the "lower turbulent zone" (LTZ). The Lester and Fingerhut study complemented previous work on wave-induced LTZs by J. P. Kuettner and others in the 1950s who were among the first to employ sailplanes as scientific measurement platforms. Given the limitations of scientific instrumentation on research aircraft in the 1970s (e.g., no GPS) and, in particular, on sailplanes in the 1950s, credit has to be given to these authors for their remarkably detailed account and classification of LTZs. Ever since then, scientists have been trying to refine the conceptual model of the LTZ and shed more light on the origin of turbulence therein. The Terrain-Induced Rotor Experiment (T-REX, Sierra Nevada, California, 2006) is the most recent, major effort organized to investigate the characteristics of LTZs by studying the coupled mountain-wave, rotor, and boundary-layer system. During T-REX, comprehensive ground-based and airborne, in situ and remote sensing measurements were collected during 15 Intensive Observation Periods (IOPs). In this study, we make use of the extensive T-REX datasets to revisit the LTZ concept. During T-REX IOPs, the University of Wyoming King Air (UWKA) research aircraft flew straight-and-level legs aligned with the mean wind direction to document the variation of flow and turbulence over and downwind of the Sierra Nevada. In order to characterize the structure and intensity of turbulence within the LTZ, turbulent kinetic energy (TKE) and eddy-dissipation rate (EDR) were computed from UWKA research flights. In contrast to the rough average values of TKE and EDR

  4. The Angular Momentum of Baryons and Dark Matter Halos Revisited

    Science.gov (United States)

    Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated

  5. Cameras and settings for optimal image capture from UAVs

    Science.gov (United States)

    Smith, Mike; O'Connor, James; James, Mike R.

    2017-04-01

    Aerial image capture has become very common within the geosciences due to the increasing affordability of low payload (markets. Their application to surveying has led to many studies being undertaken using UAV imagery captured from consumer grade cameras as primary data sources. However, image quality and the principles of image capture are seldom given rigorous discussion which can lead to experiments being difficult to accurately reproduce. In this contribution we revisit the underpinning concepts behind image capture, from which the requirements for acquiring sharp, well exposed and suitable imagery are derived. This then leads to discussion of how to optimise the platform, camera, lens and imaging settings relevant to image quality planning, presenting some worked examples as a guide. Finally, we challenge the community to make their image data open for review in order to ensure confidence in the outputs/error estimates, allow reproducibility of the results and have these comparable with future studies. We recommend providing open access imagery where possible, a range of example images, and detailed metadata to rigorously describe the image capture process.

  6. Novel response function resolves by image deconvolution more details of surface nanomorphology

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    2010-01-01

    A novel method of image processing is presented which relies on deconvolution of data using the response function of the apparatus. It is revealed that all the surface structures observed by digital imaging are generated by a convolution of the response function of the apparatus with the surfaces...... of distances, correction for drift phenomena and rotation in the plane of the surface. The technology may subsequently reveal more details of molecular adsorbents. The impact of in situ STM at atomic and lower resolution on imaging is discussed in the paper.......A novel method of image processing is presented which relies on deconvolution of data using the response function of the apparatus. It is revealed that all the surface structures observed by digital imaging are generated by a convolution of the response function of the apparatus with the surfaces......’ nanomorphology, which provided images of convoluted physical structures rather than images of real physical structures. In order to restore the genuine physical information on surface structures, a deconvolution using a novel response function of the feedback circuitry is required. At the highest resolution...

  7. MRI findings of Wernicke encephalopathy revisited due to hunger strike.

    Science.gov (United States)

    Unlu, Ercument; Cakir, Bilge; Asil, Talip

    2006-01-01

    The purpose of this study was to determine the characteristic magnetic resonance imaging (MRI) findings among a group of patients who presented with Wernicke encephalopathy (WE) due to the neurological complications of a long-term hunger strike (HS). MRI studies also including the fluid-attenuated inversion recovery (FLAIR) sequence and diffusion-weighted imaging (DWI) of six male patients with WE aged from 25 to 38 years (mean age 31 years) were evaluated. In all subjects, T2-weighted sequences, FLAIR and DWI revealed a signal hyperintensity within the posteromedial thalami and surrounding the third ventricle. In particular, on coronal images, the hyperintense areas around the third ventricle showed a suggestive "double wing" configuration. We observed an increased signal on proton-density and T2-weighted images in the mamillary bodies of three patients. Four patients demonstrated additional hyperintensities within the periaqueductal region and/or the tectal plate. At least one lesion area in five of six patients demonstrated contrast enhancement. The consistent imaging findings of our study suggest that MRI is a reliable means of diagnosing WE. Acute WE is sometimes underdiagnosed, yet early diagnosis and treatment of WE is crucial in order to avoid persistent brain damage. MRI, including postcontrast T1-weighted imaging, DWI beneath standardized T2-weighted imaging, and FLAIR sequences may prove to be a valuable adjunct to clinical diagnosis and to provide additional information in acute and/or subacute WE.

  8. MRI findings of Wernicke encephalopathy revisited due to hunger strike

    Energy Technology Data Exchange (ETDEWEB)

    Unlu, Ercument [Department of Radiology, Trakya University School of Medicine, Mimar Sinan m, Muammer Aksoy c, Yorulmaz apt, No 50, D-1 22030 Edirne (Turkey)]. E-mail: drercument@yahoo.com; Cakir, Bilge [Department of Radiology, Trakya University School of Medicine, Mimar Sinan m, Muammer Aksoy c, Yorulmaz apt, No 50, D-1 22030 Edirne (Turkey); Asil, Talip [Department of Neurology, Trakya University School of Medicine, Edirne (Turkey)

    2006-01-15

    Background and Purpose: The purpose of this study was to determine the characteristic magnetic resonance imaging (MRI) findings among a group of patients who presented with Wernicke encephalopathy (WE) due to the neurological complications of a long-term hunger strike (HS). Methods: MRI studies also including the fluid-attenuated inversion recovery (FLAIR) sequence and diffusion-weighted imaging (DWI) of six male patients with WE aged from 25 to 38 years (mean age 31 years) were evaluated. Results: In all subjects, T2-weighted sequences, FLAIR and DWI revealed a signal hyperintensity within the posteromedial thalami and surrounding the third ventricle. In particular, on coronal images, the hyperintense areas around the third ventricle showed a suggestive 'double wing' configuration. We observed an increased signal on proton-density and T2-weighted images in the mamillary bodies of three patients. Four patients demonstrated additional hyperintensities within the periaqueductal region and/or the tectal plate. At least one lesion area in five of six patients demonstrated contrast enhancement. Conclusion: The consistent imaging findings of our study suggest that MRI is a reliable means of diagnosing WE. Acute WE is sometimes underdiagnosed, yet early diagnosis and treatment of WE is crucial in order to avoid persistent brain damage. MRI, including postcontrast T1-weighted imaging, DWI beneath standardized T2-weighted imaging, and FLAIR sequences may prove to be a valuable adjunct to clinical diagnosis and to provide additional information in acute and/or subacute WE.

  9. In situ scanning tunneling microscope tip treatment device for spin polarization imaging

    Science.gov (United States)

    Li, An-Ping [Oak Ridge, TN; Jianxing, Ma [Oak Ridge, TN; Shen, Jian [Knoxville, TN

    2008-04-22

    A tip treatment device for use in an ultrahigh vacuum in situ scanning tunneling microscope (STM). The device provides spin polarization functionality to new or existing variable temperature STM systems. The tip treatment device readily converts a conventional STM to a spin-polarized tip, and thereby converts a standard STM system into a spin-polarized STM system. The tip treatment device also has functions of tip cleaning and tip flashing a STM tip to high temperature (>2000.degree. C.) in an extremely localized fashion. Tip coating functions can also be carried out, providing the tip sharp end with monolayers of coating materials including magnetic films. The device is also fully compatible with ultrahigh vacuum sample transfer setups.

  10. Not all incentives wash out the warm glow: the case of blood donation revisited

    OpenAIRE

    Costa-Font, J.; Jofre-Bonet, M.; Yen, S.

    2012-01-01

    The issue of the nature of the altruism inherent in blood donation and the perverse effects of financial rewards for blood and/or organ donation has been recently revisited in the economic literature with limited consensus. As Titmuss (1970) famously pointed out, providing monetary incentives to blood donors may crowd out blood supply as purely altruistic donors may feel less inclined to donate if a reward is involved - in addition to having the effect of reducing blood quality. In this paper...

  11. Revisiting the Capture of Mercury into Its 3:2 Spin-orbit Resonance

    Science.gov (United States)

    2014-01-01

    well before differentiation. Keywords. celestial mechanics, planets and satellites: individual ( Mercury ) 1. Previous studies In the literature hitherto...2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Revisiting the capture of Mercury into its 3:2 spin-orbit...PERFORMING ORGANIZATION NAME (S) AND ADDRESS(ES) United States Naval Observatory,,Washington,,DC,20392 8. PERFORMING ORGANIZATION REPORT NUMBER 9

  12. Re-visiting RHIC snakes: OPERA fields, n0 dance

    Energy Technology Data Exchange (ETDEWEB)

    Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gupta, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-09-22

    In this Tech. Note RHIC snakes and stable spin direction $\\vector{n}$0(s) are re-visited, based on OPERA-computed field maps of the former. The numerical simulations so undertaken provide various outcomes regarding RHIC optics and spin dynamics, in relation with orbital and focusing effects resulting from the use of this realistic 3-D representation of the snakes.

  13. Revisiting the ‘Low BirthWeight paradox’ using a model-based definition

    OpenAIRE

    Juárez, Sol; Ploubidis, George B.; Clarke, Lynda

    2014-01-01

    Introduction: Immigrant mothers in Spain have a lower risk of delivering Low BirthWeight (LBW) babies in comparison to Spaniards (LBW paradox). This study aimed at revisiting this finding by applying a model-based threshold as an alternative to the conventional definition of LBW. Methods: Vital information data from Madrid was used (2005–2006). LBW was defined in two ways (less than 2500 g and Wilcox's proposal). Logistic and linear regression models were run. Results: According to comm...

  14. Clostridium sticklandii, a specialist in amino acid degradation:revisiting its metabolism through its genome sequence

    OpenAIRE

    Fonknechten, Nuria; Chaussonnerie, Sébastien; Tricot, Sabine; Lajus, Aurélie; Andreesen, Jan R; Perchat, Nadia; Pelletier, Eric; Gouyvenoux, Michel; Barbe, Valérie; Salanoubat, Marcel; Le Paslier, Denis; Weissenbach, Jean; Cohen, Georges N; Kreimeyer, Annett

    2010-01-01

    Abstract Background Clostridium sticklandii belongs to a cluster of non-pathogenic proteolytic clostridia which utilize amino acids as carbon and energy sources. Isolated by T.C. Stadtman in 1954, it has been generally regarded as a "gold mine" for novel biochemical reactions and is used as a model organism for studying metabolic aspects such as the Stickland reaction, coenzyme-B12- and selenium-dependent reactions of amino acids. With the goal of revisiting its carbon, nitrogen, and energy m...

  15. Revisiting the fundamental physical chemistry in heterogeneous photocatalysis: its thermodynamics and kinetics.

    Science.gov (United States)

    Ohtani, Bunsho

    2014-02-07

    Although the history of photocatalysis research is not so long, many researchers have studied photocatalysis and a large number of papers on photocatalysis have been published. The objectives of this review paper are to revisit the fundamentals of photocatalysis, especially its thermodynamics and kinetics, which have not been reexamined in recent studies, to clarify the problems, if any, that prevent developments in the field of photocatalysis, and to present insights for future progress.

  16. Revisiting the fundamental physical chemistry in heterogeneous photocatalysis : its thermodynamics and kinetics

    OpenAIRE

    Ohtani, Bunsho

    2014-01-01

    Although the history of photocatalysis research is not so long, many researchers have studied photocatalysis and a large number of papers on photocatalysis have been published. The objectives of this review paper are to revisit the fundamentals of photocatalysis, especially its thermodynamics and kinetics, which have not been reexamined in recent studies, to clarify the problems, if any, that prevent developments in the field of photocatalysis, and to present insights for future progress.

  17. Revisit boundary conditions for the self-adjoint angular flux formulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yaqi [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gleicher, Frederick N. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    We revisit the boundary conditions for SAAF. We derived the equivalent parity variational form ready for coding up. The more rigorous approach of evaluating odd parity should be solving the odd parity equation coupled with the even parity. We proposed a symmetric reflecting boundary condition although neither positive definiteness nor even-odd decoupling is achieved. A simple numerical test verifies the validity of these boundary conditions.

  18. Taï chimpanzees anticipate revisiting high-valued fruit trees from further distances.

    Science.gov (United States)

    Ban, Simone D; Boesch, Christophe; Janmaat, Karline R L

    2014-11-01

    The use of spatio-temporal memory has been argued to increase food-finding efficiency in rainforest primates. However, the exact content of this memory is poorly known to date. This study investigated what specific information from previous feeding visits chimpanzees (Pan troglodytes verus), in Taï National Park, Côte d'Ivoire, take into account when they revisit the same feeding trees. By following five adult females for many consecutive days, we tested from what distance the females directed their travels towards previously visited feeding trees and how previous feeding experiences and fruit tree properties influenced this distance. To exclude the influence of sensory cues, the females' approach distance was measured from their last significant change in travel direction until the moment they entered the tree's maximum detection field. We found that chimpanzees travelled longer distances to trees at which they had previously made food grunts and had rejected fewer fruits compared to other trees. In addition, the results suggest that the chimpanzees were able to anticipate the amount of fruit that they would find in the trees. Overall, our findings are consistent with the hypothesis that chimpanzees act upon a retrieved memory of their last feeding experiences long before they revisit feeding trees, which would indicate a daily use of long-term prospective memory. Further, the results are consistent with the possibility that positive emotional experiences help to trigger prospective memory retrieval in forest areas that are further away and have fewer cues associated with revisited feeding trees.

  19. RNS derivation of N-point disk amplitudes from the revisited S-matrix approach

    Energy Technology Data Exchange (ETDEWEB)

    Barreiro, Luiz Antonio, E-mail: luiz.a.barreiro@gmail.com [Departamento de Física, UNESP, Rio Claro, São Paulo (Brazil); Instituto de Matemática e Computação, Universidade Federal de Itajubá, Itajubá, Minas Gerais (Brazil); Medina, Ricardo, E-mail: rmedina50@gmail.com [Instituto de Matemática e Computação, Universidade Federal de Itajubá, Itajubá, Minas Gerais (Brazil)

    2014-09-15

    Recently, in [7] we proposed a revisited S-matrix approach to efficiently find the bosonic terms of the open superstring low energy effective lagrangian (OSLEEL). This approach allows to compute the α{sup ′N} terms of the OSLEEL using open superstring n-point amplitudes in which n is considerably lower than (N+2) (which is the order of the required amplitude to obtain those α{sup ′N} terms by means of the conventional S-matrix approach). In this work we use our revisited S-matrix approach to examine the structure of the scattering amplitudes, arriving at a closed form for them. This is a RNS derivation of the formula first found by Mafra, Schlotterer and Stieberger [21], using the pure spinor formalism. We have succeeded doing this for the 5, 6 and 7-point amplitudes. In order to achieve these results we have done a careful analysis of the kinematical structure of the amplitudes, finding as a by-product a purely kinematical derivation of the BCJ relations (for N=4,5,6 and 7). Also, following the spirit of the revisited S-matrix approach, we have found the α{sup ′} expansions for these amplitudes up to α{sup ′6} order in some cases, by only using the well known open superstring 4-point amplitude, cyclic symmetry and tree level unitarity: we have not needed to compute any numerical series or any integral involving polylogarithms, at any moment.

  20. The SAPHO syndrome revisited with an emphasis on spinal manifestations

    Energy Technology Data Exchange (ETDEWEB)

    Leone, Antonio; Casale, Roberto; Magarelli, Nicola; Semprini, Alessia; Colosimo, Cesare [Catholic University, School of Medicine, Department of Radiological Sciences, Rome (Italy); Cassar-Pullicino, Victor N. [The Robert Jones and Agnes Hunt Orthopaedic and District Hospital, Department of Diagnostic Imaging, Shropshire, England (United Kingdom)

    2015-01-15

    The synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome includes a group of chronic, relapsing, inflammatory musculoskeletal disorders with similar manifestations, in particular synovitis, hyperostosis, and osteitis, which may or may not be associated with neutrophilic skin eruptions such as palmoplantar pustulosis and acne conglobata. The syndrome occurs at any age, can involve any skeletal site, and its imaging appearances are variable, depending on the stage/age of the lesion and imaging method. The diagnosis is difficult if there is no skin disease. Awareness of the imaging appearances, especially in the spine, may help the radiologist in avoiding misdiagnosis (e.g., infection, tumor) and unnecessary invasive procedures, while facilitating early diagnosis and selection of an effective treatment. In this article, we provide an overview of the radiological appearances of SAPHO syndrome, focusing on the magnetic resonance imaging findings of vertebral involvement, and present relevant clinical and pathological features that assist early diagnosis. (orig.)