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Sample records for evanescent field surrounding

  1. Non-linear evanescent-field imaging

    Energy Technology Data Exchange (ETDEWEB)

    Oheim, Martin [Laboratory of Neurophysiology and New Microscopies, CNRS FRE 2500, INSERM U 603, Ecole Superieure de Physique et Chimie Industrielles (ESPCI), 10 rue Vauquelin, F-75005 Paris (France); Schapper, Florian [Freie Universitaet Berlin, Institut fuer Experimentalphysik, Arbeitsgruppe Wolf, Arnimallee 14, D-14195 Berlin (Germany)

    2005-05-21

    Total internal reflection fluorescence (TIRF), a general term that embraces any spectroscopic or microscopic technique based on the evanescent field created by TIR of light, is further establishing itself as an important tool for studying near-surface phenomena. Impingement of a femtosecond-pulsed infrared beam on a reflecting interface creates the conditions for 'macroscopic' evanescent-field two-photon fluorescence excitation. The two-photon fluorescence excitation volume is confined by both the non-linearity of the multi-photon process and the spatial inhomogeneity of the evanescent field. The absence of scattered excitation resulting in a low background and the possibility of simultaneous multi-colour fluorescence excitation should make non-linear evanescent-field excitation particularly attractive for quantitative single-molecule observation and ultra-sensitive screening assays. In this topical review, we survey the requirements, present the current results and explore the potential of this novel non-linear microscopy. (topical review)

  2. An Evanescent Field Optical Microscope. Scanning probe Microscopy

    NARCIS (Netherlands)

    van Hulst, N.F.; Segerink, Franciscus B.; Bölger, B.; Bölger, B.; Wickramasinghe, H. Kumar

    1991-01-01

    An Evanescent Field Optical Microscope (EFOM) is presented, which employs frustrated total internal reflection on a highly localized scale by means of a sharp dielectric tip. The coupling of the evanescent field to the sub-micrometer probe as a function of probe-sample distance, angle of incidence

  3. TIRF microscopy evanescent field calibration using tilted fluorescent microtubules.

    Science.gov (United States)

    Gell, C; Berndt, M; Enderlein, J; Diez, S

    2009-04-01

    Total internal reflection fluorescence microscopy has become a powerful tool to study the dynamics of sub-cellular structures and single molecules near substrate surfaces. However, the penetration depth of the evanescent field, that is, the distance at which the excitation intensity has exponentially decayed to 1/e, is often left undetermined. This presents a limit on the spatial information about the imaged structures. Here, we present a novel method to quantitatively characterize the illumination in total internal reflection fluorescence microscopy using tilted, fluorescently labelled, microtubules. We find that the evanescent field is well described by a single exponential function, with a penetration depth close to theoretically predicted values. The use of in vitro reconstituted microtubules as nanoscale probes results in a minimal perturbation of the evanescent field; excitation light scattering is eliminated and the refractive index of the sample environment is unchanged. The presented method has the potential to provide a generic tool for in situ calibration of the evanescent field.

  4. Fiber-optic evanescent-field sensor for attitude measurement

    Science.gov (United States)

    Liu, Yun; Chen, Shimeng; Liu, Zigeng; Guang, Jianye; Peng, Wei

    2017-11-01

    We proposed a new approach to attitude measurement by an evanescent field-based optical fiber sensing device and demonstrated a liquid pendulum. The device consisted of three fiber-optic evanescent-filed sensors which were fabricated by tapered single mode fibers and immersed in liquid. Three fiber Bragg gratings were used to measure the changes in evanescent field. And their reflection peaks were monitored in real time as measurement signals. Because every set of reflection responses corresponded to a unique attitude, the attitude of the device could be measured by the three fiber-optic evanescent-filed sensors. After theoretical analysis, computerized simulation and experimental verification, regular responses were obtained using this device for attitude measurement. The measurement ranges of dihedral angle and direction angle were 0°–50° and 0°–360°. The device is based on cost-effective power-referenced scheme. It can be used in electromagnetic or nuclear radiation environment.

  5. Transfer function and near-field detection of evanescent waves

    DEFF Research Database (Denmark)

    Radko, Ylia P.; Bozhevolnyi, Sergey I.; Gregersen, Niels

    2006-01-01

    for the transfer function, which is derived by introducing an effective pointof (dipolelike) detection inside the probe tip. It is found to be possible to fit reasonably well both the experimental and the simulation data for evanescent field components, implying that the developed approximation of the near-field...... of collection and illumination modes. Making use of a collection near-field microscope with a similar fiber tip illuminated by an evanescent field, we measure the collected power as a function of the field spatial frequency in different polarization configurations. Considering a two-dimensional probe...... configuration, numerical simulations of detection efficiency based on the eigenmode expansion technique are carried out for different tip apex angles. The detection roll-off for high spatial frequencies observed in the experiment and obtained during the simulations is fitted using a simple expression...

  6. Suppression of sound radiation to far field of near-field acoustic communication system using evanescent sound field

    OpenAIRE

    Fujii, Ayaka; Wakatsuki, Naoto; Mizutani, Koichi

    2016-01-01

    A method of suppressing sound radiation to the far field of a near-field acoustic communication system using an evanescent sound field is proposed. The amplitude of the evanescent sound field generated from an infinite vibrating plate attenuates exponentially with increasing a distance from the surface of the vibrating plate. However, a discontinuity of the sound field exists at the edge of the finite vibrating plate in practice, which broadens the wavenumber spectrum. A sound wave radiates o...

  7. Optical theorem for electromagnetic field scattering by dielectric structures and energy emission from the evanescent wave.

    Science.gov (United States)

    Gulyaev, Yu V; Barabanenkov, Yu N; Barabanenkov, M Yu; Nikitov, S A

    2005-08-01

    We present an optical theorem for evanescent (near field) electromagnetic wave scattering by a dielectric structure. The derivation is based on the formalism of angular spectrum wave amplitudes and block scattering matrix. The optical theorem shows that an energy flux is emitted in the direction of the evanescent wave decay upon scattering. The energy emission effect from an evanescent wave is illustrated in two examples of evanescent wave scattering, first, by the electrical dipole and, second, one-dimensional grating with line-like rulings. Within the latter example, we show that an emitted energy flux upon evanescent wave scattering can travel through a dielectric structure even if the structure has a forbidden gap in the transmission spectrum of incident propagating waves.

  8. Resonant energy transfer under the influence of the evanescent field from the metal.

    Science.gov (United States)

    Poudel, Amrit; Chen, Xin; Ratner, Mark A

    2017-06-28

    We present a quantum framework based on a density matrix of a dimer system to investigate the quantum dynamics of excitation energy transfer (EET) in the presence of the evanescent field from the metal and the phonon bath. Due to the spatial correlation of the electric field in the vicinity of the metal, the spectral density of the evanescent field is similar to that of a shared phonon bath. However, the EET dynamics under the influence of the evanescent field is an open and a new problem. Here we use a thin metallic film to investigate the effect of the evanescent field on the excitation energy transfer in a dimer system based on a density matrix approach. Our results indicate that a thin metallic film enhances the energy transfer rate at the expense of absorbing energy during the process. Since the spectral density of the evanescent field is affected by the geometry of the medium and the distance of a dimer system from the medium, our results demonstrate the possibility to tune EET based on material geometry and distances. Our model also serves as an expansion to quantum heat engine models and provides a framework to investigate the EET in light harvesting molecular networks under the influence of the evanescent field.

  9. Resonant energy transfer under the influence of the evanescent field from the metal

    Science.gov (United States)

    Poudel, Amrit; Chen, Xin; Ratner, Mark A.

    2017-06-01

    We present a quantum framework based on a density matrix of a dimer system to investigate the quantum dynamics of excitation energy transfer (EET) in the presence of the evanescent field from the metal and the phonon bath. Due to the spatial correlation of the electric field in the vicinity of the metal, the spectral density of the evanescent field is similar to that of a shared phonon bath. However, the EET dynamics under the influence of the evanescent field is an open and a new problem. Here we use a thin metallic film to investigate the effect of the evanescent field on the excitation energy transfer in a dimer system based on a density matrix approach. Our results indicate that a thin metallic film enhances the energy transfer rate at the expense of absorbing energy during the process. Since the spectral density of the evanescent field is affected by the geometry of the medium and the distance of a dimer system from the medium, our results demonstrate the possibility to tune EET based on material geometry and distances. Our model also serves as an expansion to quantum heat engine models and provides a framework to investigate the EET in light harvesting molecular networks under the influence of the evanescent field.

  10. Fiber-optic evanescent-field laser sensor for in-situ gas diagnostics.

    Science.gov (United States)

    Willer, Ulrike; Scheel, Dirk; Kostjucenko, Irina; Bohling, Christian; Schade, Wolfgang; Faber, Eckhard

    2002-09-01

    A compact, rugged and portable fiber-optic evanescent-field laser sensor is developed for the detection of gaseous species in harsh environments such as volcano fumaroles or industrial combustion of glass furnaces. The sensor consists of an optical multi-mode fused silica fiber with jacket and cladding removed and the bare fiber core in direct contact with the surrounding molecules. The beam of a single-mode DFB diode laser with an emission wavelength centered at 1.5705 microm is coupled into the fiber. At the other end of the fiber an infrared detector is used to record the transmitted infrared laser light intensity. Due to the frustrated total reflection (FTR) and the attenuated total reflection (ATR) the laser intensity is attenuated when passing through the fiber. The FTR is related to a change of the index of refraction while the latter one is related to a change of the absorption coefficient. While tuning the DFB laser wavelength across absorption lines of molecules surrounding the fiber a spectral intensity profile is measured. Voigt functions are fitted to the recorded intensity profiles to estimate relative molecule concentrations. In this paper results from first field measurements at the volcano site 'Solfatara' in Italy are reported that use such a sensor device for simultaneous detection of H2S, CO2 and H2O directly in the gas stream of a volcano fumarole.

  11. Selective particle trapping and optical binding in the evanescent field of an optical nanofiber

    CERN Document Server

    Frawley, Mary C; Truong, Viet Giang; Sergides, Marios; Chormaic, Síle Nic

    2014-01-01

    The evanescent field of an optical nanofiber presents a versatile interface for the manipulation of micron-scale particles in dispersion. Here, we present a detailed study of the optical binding interactions of a pair of 3.13 $\\mu$m SiO$_2$ particles in the nanofiber evanescent field. Preferred equilibrium positions for the spheres as a function of nanofiber diameter and sphere size are discussed. We demonstrated optical propulsion and self-arrangement of chains of one to seven 3.13 $\\mu$m SiO$_2$ particles; this effect is associated with optical binding via simulated trends of multiple scattering effects. Incorporating an optical nanofiber into an optical tweezers setup facilitated the individual and collective introduction of selected particles to the nanofiber evanescent field for experiments. Computational simulations provide insight into the dynamics behind the observed behavior.

  12. Detection of surface-plasmon evanescent fields using a metallic probe tip covered with fluorescence

    CERN Document Server

    Wakamatsu, T; Shinbo, K; Kato, K; Kaneko, F

    1999-01-01

    A new experimental system has been constructed to detect evanescent fields of metal surface plasmons (SPs) using a metallic probe tip covered with fluorescence cadmium sulfide (CdS). The evanescent fields of the SPs sensitive to the metal interfaces were observed as fluorescent light from CdS on the tip. No additional lock-in detection technique with a vibrating probe tip is necessary in the system, in spite of the scattered light enhanced by SP due to the surface roughness. The fluorescent light measured for the Al film sample shows exponential decay with distance from the sample surface, indicating that the SP evanescent fields are detected with our apparatus. (10 refs).

  13. Yb:KYW planar waveguide laser Q-switched by evanescent-field interaction with carbon nanotubes

    NARCIS (Netherlands)

    Kim, Jun Wan; Choi, Sun Young; Yeom, Dong-Il; Aravazhi, S.; Pollnau, Markus; Griebner, Uwe; Petrov, Valentin; Rotermund, Fabian

    2013-01-01

    We report Q-switched operation of a planar waveguide laser by evanescent-field interaction with single-walled carbon nanotubes deposited on top of the waveguide. The saturable-absorber-integrated gain medium, which operates based on evanescent-field interaction, enables the realization of a

  14. Optical waveguides formed by silver ion exchange in Schott SG11 glass for waveguide evanescent field fluorescence microscopy: evanescent images of HEK293 cells.

    Science.gov (United States)

    Hassanzadeh, Abdollah; Nitsche, Michael; Armstrong, Souzan; Nabavi, Noushin; Harrison, Rene; Dixon, S Jeffrey; Langbein, Uwe; Mittler, Silvia

    2010-01-01

    Planar glass waveguides with a specific number of modes were fabricated by Ag(+)-Na(+) exchange in Schott SG11 glass. The effective refractive indices were determined using m-line spectroscopy in both s- and p-polarization. By using the reversed Wentzel-Kramers-Brillouin approximation, the index profiles were described by a nonlinear diffusion equation. The diffusion coefficients for Ag(+) were established, as well as the penetration depth of the evanescent field in an aqueous environment for the different modes. The integrals of \\E\\(2) fields for the evanescent-guided fields were investigated. These are important when evanescent fields are used for illumination in interface microscopy, an alternative method to total internal reflection fluorescence (TIRF) microscopy. The photoluminescent behavior of the waveguides was investigated as a function of ion exchange time and excitation wavelengths. Comparable images were obtained of fluorescently labeled HEK293 cells using TIRF microscopy and waveguide evanescent field fluorescence microscopy. Imaging was performed using HEK293 cells, delivering similar images and information.

  15. Near-field imaging of interference pattern of counterpropagating evanescent waves

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Bozhevolnaya, Elena A.

    1999-01-01

    It is generally accepted that measurement of of the contrast of the intensity interference pattern formed by two counterpropagating evanescent waves can be used to characterize the resolving power of a collection near-field microscope. We argue that, if the light collected by a fiber probe...

  16. High resolution imaging of dielectric surfaces with an evanescent field optical microscope

    NARCIS (Netherlands)

    van Hulst, N.F.; Segerink, Franciscus B.; Bölger, B.

    1992-01-01

    An evanescent field optical microscope (EFOM) is presented which employs frustrated total internal reflection o­n a localized scale by scanning a dielectric tip in close proximity to a sample surface. High resolution images of dielectric gratings and spheres containing both topographic and

  17. Simple algorithm for partial wave expansion of plasmonic and evanescent fields.

    Science.gov (United States)

    Yu, Xinning; Ye, Qian; Chen, Huajin; Liu, Shiyang; Lin, Zhifang

    2017-02-20

    Based on an expansion formula for unit dyadic in terms of the vector spherical wave functions, we derive explicit partial wave coefficients for a complex wave vector field that is characterized by a single wave vector with three Cartesian components being arbitrarily constant complex except subject to lossless background constraint and thus includes evanescent waves and simple plasmonic fields as its two special cases. A recurrence method is then proposed to evaluate the partial wave expansion coefficients numerically up to arbitrary order of expansion, offering an efficient tool for the scattering of generic electromagnetic fields that can be modelled by a superposition of the complex wave vector fields such as the evanescent and plasmonic waves. Our approach is validated by analytically working out the integration in the conventional, more cumbersome, projection approach. Comparison of optical forces on a particle in evanescent and plasmonic fields with previous results shows perfect agreement, thereby further corroborating our approach. As examples of its application, we calculate optical force and torque exerting on particles residing in a plasmonic field, with large particle size where the conventional projection method based on the direct numerical integration is unadapted due to the difficulty in convergence. It is found that the direction of optical torque stays parallel to the direction of spin of optical field for some field polarizations and changes for some other polarizations, as the particle radius R varies.

  18. Suppression of sound radiation to far field of near-field acoustic communication system using evanescent sound field

    Science.gov (United States)

    Fujii, Ayaka; Wakatsuki, Naoto; Mizutani, Koichi

    2016-01-01

    A method of suppressing sound radiation to the far field of a near-field acoustic communication system using an evanescent sound field is proposed. The amplitude of the evanescent sound field generated from an infinite vibrating plate attenuates exponentially with increasing a distance from the surface of the vibrating plate. However, a discontinuity of the sound field exists at the edge of the finite vibrating plate in practice, which broadens the wavenumber spectrum. A sound wave radiates over the evanescent sound field because of broadening of the wavenumber spectrum. Therefore, we calculated the optimum distribution of the particle velocity on the vibrating plate to reduce the broadening of the wavenumber spectrum. We focused on a window function that is utilized in the field of signal analysis for reducing the broadening of the frequency spectrum. The optimization calculation is necessary for the design of window function suitable for suppressing sound radiation and securing a spatial area for data communication. In addition, a wide frequency bandwidth is required to increase the data transmission speed. Therefore, we investigated a suitable method for calculating the sound pressure level at the far field to confirm the variation of the distribution of sound pressure level determined on the basis of the window shape and frequency. The distribution of the sound pressure level at a finite distance was in good agreement with that obtained at an infinite far field under the condition generating the evanescent sound field. Consequently, the window function was optimized by the method used to calculate the distribution of the sound pressure level at an infinite far field using the wavenumber spectrum on the vibrating plate. According to the result of comparing the distributions of the sound pressure level in the cases with and without the window function, it was confirmed that the area whose sound pressure level was reduced from the maximum level to -50 dB was

  19. Evanescent magnetic field effects on entropy generation at the onset ...

    Indian Academy of Sciences (India)

    MS received 29 November 2008; revised 14 October 2009; accepted 20 October. 2010. Abstract. This paper numerically investigates the effect of an externally evanes- cent magnetic field on total entropy generation in a fluid enclosed in a square cavity by using a control volume finite element method to solve the ...

  20. Dispersive optomechanical coupling between a SiN nanomechanical oscillator and evanescent fields of a silica optical resonator

    Science.gov (United States)

    Dong, Chunhua; Htay Oo, Thein; Fiore, Victor; Wang, Hailin

    2013-03-01

    Tensile stressed SiN nanostrings can feature a picogram effective mass and a mechanical Q-factor exceeding a million. These remarkable nanomechanical oscillators can be dispersively-coupled to an ultra-high finesse optical microresonator via its evanescent field. This composite optomechanical system can potentially lead to a cooperativity that far exceeds that of monolithic optomechanical resonators. Here, we report an experimental study coupling a SiN nanostring to evanescent fields of a whispering gallery mode (WGM) in a silica microsphere. The slight deformation of the microsphere enables us to use free-space optical excitation to probe the optomechanical coupling. The dispersive coupling between a nanostring and the evanescent field of a WGM is generally expected to lead to a red shift in the resonance frequency of the WGM. Our experiments, however, reveal a blue frequency shift of the WGM. Detailed experimental studies and possible physical mechanisms for the blue shift will be presented.

  1. Detection of C-reactive protein in evanescent wave field using microparticle-tracking velocimetry.

    Science.gov (United States)

    Fan, Yu-Jui; Sheen, Horn-Jiunn; Liu, Yi-Hsing; Tsai, Jing-Fa; Wu, Tzu-Heng; Wu, Kuang-Chong; Lin, Shiming

    2010-09-07

    A new technique is developed to measure the nanoparticles' brownian motions by employing microparticle-tracking velocimetry (micro-PTV) in evanescent wave field, which can provide high signal-to-noise ratio images for analyzing nanoparticles' movements. This method enables real-time detection of C-reactive proteins (CRPs) during the rapid interaction between CRPs and anti-CRP-coated nanobeads as CRP concentrations are related to the nanobeads' brownian velocity in the equilibrium state. The smallest observable nanobeads with 185 nm were utilized in this experiment to detect CRP concentrations as low as 0.1 microg/mL even in a high-viscosity solution. Further, the dissociation constant, K(D), can be evaluated based on the experimental results.

  2. Fluorometer with a quartz-rod waveguide-integrating sphere configuration to measure evanescent-field luminescence

    Science.gov (United States)

    A fluorometer was designed to measure evanescent-field luminescence. A quartz-rod waveguide (d = 2 mm) was installed coaxally inside a cylindrical flow-through cell (id = 2.3 mm, od = 6.3 mm, l = 116 mm). An excitation beam from a UV LED or a miniature xenon flashlamp was focused by a ball lens and ...

  3. Evanescent field phase shifting in a silicon nitride waveguide using a coupled silicon slab

    DEFF Research Database (Denmark)

    Jensen, Asger Sellerup; Oxenløwe, Leif Katsuo; Green, William M. J.

    2015-01-01

    An approach for electrical modulation of low-loss silicon nitride waveguides is proposed, using a silicon nitride waveguide evanescently loaded with a thin silicon slab. The thermooptic phase-shift characteristics are investigated in a racetrack resonator configuration.......An approach for electrical modulation of low-loss silicon nitride waveguides is proposed, using a silicon nitride waveguide evanescently loaded with a thin silicon slab. The thermooptic phase-shift characteristics are investigated in a racetrack resonator configuration....

  4. Optical response of magnetic fluorescent microspheres used for force spectroscopy in the evanescent field.

    Science.gov (United States)

    Bijamov, Alex; Shubitidze, Fridon; Oliver, Piercen M; Vezenov, Dmitri V

    2010-07-20

    Force spectroscopy based on magnetic tweezers is a powerful technique for manipulating single biomolecules and studying their interactions. The resolution in magnetic probe displacement, however, needs to be commensurate with molecular sizes. To achieve the desirable sensitivity in tracking displacements of the magnetic probe, some recent approaches have combined magnetic tweezers with total internal reflection fluorescence microscopy. In this situation, a typical force probe is a polymer microsphere containing two types of optically active components: a pure absorber (magnetic nanoparticles for providing the pulling force) and a luminophore (semiconducting nanoparticles or organic dyes for fluorescent imaging). To assess the system's capability fully with regard to tracking the position of the force probe with subnanometer accuracy, we developed a body-of-revolution formulation of the method of auxiliary sources (BOR-MAS) to simulate the absorption, scattering, and fluorescence of microscopic spheres in an evanescent electromagnetic field. The theoretical formulation uses the axial symmetry of the system to reduce the dimensionality of the modeling problem and produces excellent agreement with the reported experimental data on forward scattering intensity. Using the BOR-MAS numerical model, we investigated the probe detection sensitivity for a high numerical aperture objective. The analysis of both backscattering and fluorescence observation modes shows that the total intensity of the bead image decays exponentially with the distance from the surface (or the length of a biomolecule). Our investigations demonstrate that the decay lengths of observable optical power are smaller than the penetration depth of the unperturbed excitation evanescent wave. In addition, our numerical modeling results illustrate that the expected sensitivity for the decay length changes with the angle of incidence, tracking the theoretical penetration depth for a two-media model, and is

  5. Photonic crystal cavities for resonant evanescent field trapping of single bacteria

    Science.gov (United States)

    van Leest, Thijs; Heldens, Jeroen; van der Gaag, Bram; Caro, Jaap

    2012-06-01

    In monitoring the quality of drinking water with respect to the presence of hazardous bacteria there is a strong need for on-line sensors that allow quick identification of bacterium species at low cost. In this respect, the combination of photonics and microfluidics is promising for lab-on-a-chip sensing of these contaminants. Photonic crystal slabs have proven to form a versatile platform for controlling the flow of light and creating resonant cavities on a wavelength scale. The goal of our research is to use photonic crystal cavities for optical trapping of microorganisms in water, exploiting the enhanced evanescent field of the cavity mode. We optimize the H0, H1 and L3 cavities for optical trapping of bacteria in water, by reducing out-of-plane losses and taking into account the trapping-induced resonance shift and the in-plane coupling with photonic crystal waveguides. The cavities are fabricated on silicon-on-insulator material, using e-beam lithography and dry etching. A fluidic channel is created on top of the photonic crystal using dry film resist techniques. Transmission measurements show clear resonances for the cavities in water. In the present state of our research, we demonstrate optical trapping of 1 μm diameter polystyrene beads for the three cavities, with estimated trapping forces on the order of 0.7 pN.

  6. Influence of dsDNA fragment length on particle binding in an evanescent field biosensing system.

    Science.gov (United States)

    Koets, Marjo; van Ommering, Kim; Wang, Liqin; Testori, Emilie; Evers, Toon H; Prins, Menno W J

    2014-04-07

    Particle labels are widely used in affinity-based biosensing due to the high detection signal per label, the high stability, and the convenient biofunctionalization of particles. In this paper we address the question how the time-course of particle binding and the resulting signals depend on the length of captured target molecules. As a model system we used fragments of dsDNA with lengths of 105 bp (36 nm), 290 bp (99 nm) and 590 bp (201 nm), detected in an evanescent-field optomagnetic biosensing system. On both ends the fragments were provided with small-molecule tags to allow binding of the fragments to protein-coated particles and to the capture molecules at the sensor surface. For isolated single particles bound to the surface, we observe that the optical scattering signal per particle depends only weakly on the fragment length, which we attribute to the pivoting motion that allows the particles to get closer to the surface. Our data show a strong influence of the fragment length on the particle binding: the binding rate of particles to the sensor surface is an order of magnitude higher for the longest dsDNA fragments compared to the smallest fragment studied in this paper. We attribute the enhanced binding rate to the length and motional freedom of the fragments. These results generate a new dimension for the design of assays and systems in particle-based biosensing.

  7. Evanescent field Sensors Based on Tantalum Pentoxide Waveguides – A Review

    OpenAIRE

    Christian Hoffmann; Gerd Sulz; Kerstin Oehse; Katrin Schmitt

    2008-01-01

    Evanescent field sensors based on waveguide surfaces play an important rolewhere high sensitivity is required. Particularly tantalum pentoxide (Ta2O5) is a suitablematerial for thin-film waveguides due to its high refractive index and low attenuation.Many label-free biosensor systems such as grating couplers and interferometric sensors aswell as fluorescence-based systems benefit from this waveguide material leading toextremely high sensitivity. Some biosensor systems based on Ta2O5 waveguide...

  8. Evanescent field microscopy techniques for studying dynamics at the surface of living cells

    Science.gov (United States)

    Sund, Susan E.

    This thesis presents two distinct optical microscopy techniques for applications in cell biophysics: (a)the extension to living cells of an established technique, total internal reflection/fluorescence recovery after photobleaching (TIR/FRAP) for the first time in imaging mode; and (b)the novel development of polarized total internal reflection fluorescence (p- TIRF) to study membrane orientation in living cells. Although reversible chemistry is crucial to dynamical processes in living cells, relatively little is known about the relevant chemical kinetic rates in vivo. TIR/FRAP, an established technique which can measure reversible biomolecular kinetic rates at surfaces, is extended here to measure kinetic parameters of microinjected rhodamine actin at the cytofacial surface of the plasma membrane of living cultured smooth muscle cells. For the first time, spatial imaging (with a CCD camera) is used in conjunction with TIR/FRAP. TIR/FRAP imaging allows production of spatially resolved images of kinetic data, and calculation of correlation distances, cell-wide gradients, and kinetic parameter dependence on initial fluorescence intensity. In living cells, membrane curvature occurs both in easily imaged large scale morphological features, and also in less visualizable submicroscopic regions of activity such as endocytosis, exocytosis, and cell surface ruffling. A fluorescence microscopic method, p-TIRF, is introduced here to visualize such regions. The method is based on fluorescence of the oriented membrane probe diI- C18-(3) (diI) excited by evanescent field light polarized either perpendicular or parallel to the plane of the substrate coverslip. The excitation efficiency from each polarization depends on the membrane orientation, and thus the ratio of the observed fluorescence excited by these two polarizations vividly shows regions of microscopic and submicroscopic curvature of the membrane. A theoretical background of the technique and experimental verifications

  9. Evanescent field interaction of tapered fiber with graphene oxide in generation of wide-bandwidth mode-locked pulses

    Science.gov (United States)

    Ahmad, H.; Faruki, M. J.; Razak, M. Z. A.; Tiu, Z. C.; Ismail, M. F.

    2017-02-01

    Pulses with picosecond pulse widths are highly desired for high precision laser applications. A mode-locked pulse laser utilizing evanescent field interaction of a tapered fiber with graphene oxide (GO) is demonstrated. A homemade fabrication stage was used to fabricate the tapered fiber using systematic flame brushing and a GO solution was used to coat the microfiber using optical deposition technique. Pulse trains with a pulse width of 3.46 ps, a 3 dB optical bandwidth of 11.82 nm and a repetition rate of 920 kHz were obtained. The system has substantial potential for many crucial medical, communication, bio processing, military, and industrial applications.

  10. Evanescent field Sensors Based on Tantalum Pentoxide Waveguides – A Review

    Directory of Open Access Journals (Sweden)

    Christian Hoffmann

    2008-01-01

    Full Text Available Evanescent field sensors based on waveguide surfaces play an important rolewhere high sensitivity is required. Particularly tantalum pentoxide (Ta2O5 is a suitablematerial for thin-film waveguides due to its high refractive index and low attenuation.Many label-free biosensor systems such as grating couplers and interferometric sensors aswell as fluorescence-based systems benefit from this waveguide material leading toextremely high sensitivity. Some biosensor systems based on Ta2O5 waveguides alreadytook the step into commercialization. This report reviews the various detection systems interms of limit of detection, the applications, and the suitable surface chemistry.

  11. Evanescent gravitational mass

    OpenAIRE

    Bel, Lluis

    2009-01-01

    A simple and {\\it innocent} modification of Poisson's equation leads to a modified Newtonnian theory of gravitation where a localized and {\\it positive} energy density of the gravitational field contributes to its own source. The result is that the total {\\it active gravitational mass} of a compact object is the sum of its {\\it proper mass} and an {\\it evanescent gravitational mass} which is a mass equivalent to the gravitational energy.

  12. Superluminal advanced transmission of X waves undergoing frustrated total internal reflection: the evanescent fields and the Goos-Hänchen effect.

    Science.gov (United States)

    Shaarawi, Amr M; Tawfik, Bassem H; Besieris, Ioannis M

    2002-10-01

    A study of X waves undergoing frustrated total internal reflection at a planar slab is provided. This is achieved by choosing the spectral plane wave components of the incident X wave to fall on the upper interface at angles greater than the critical angle. Thus, evanescent fields are generated in the slab and the peak of the field tunneling through the slab appears to be transmitted at a superluminal speed. Furthermore, it is shown that for deep barrier penetration, the peak of the transmitted field emerges from the rear interface of the slab before the incident peak reaches the front interface. To understand this advanced transmission of the peak of the pulse, a detailed study of the behavior of the evanescent fields in the barrier region is undertaken. The difference in tunneling behavior between deep and shallow barrier penetrations is shown to be influenced by the sense of the Goos-Hänchen shift.

  13. Nonlinear force dependence on optically bound arrays of micro-particles trapped in the evanescent fields of fundamental and higher order microfibre modes

    CERN Document Server

    Maimaiti, Aili; Truong, Viet Giang; Ritsch, Helmut; Chormaic, Sile Nic

    2016-01-01

    Particles trapped in the evanescent field of an ultrathin optical fibre interact over very long distances via multiple scattering of the fibre-guided fields. In ultrathin fibres that support higher order modes these interactions are stronger and exhibit qualitatively new behaviour due to the coupling of different fibre modes, which have different propagation wave vectors, by the particles. Here, we study one dimensional longitudinal optical binding interactions of chains of 3 {\\mu}m polystyrene spheres under the influence of the evanescent fields of a two-mode microfibre. The observation of long-range interactions, self-ordering and speed variation of particle chains reveals strong optical binding effects between the particles, which can be well modelled by a tritter scattering-matrix approach. The optical forces, optical binding interactions and the velocity of bounded particle chains are calculated using this method. Results show good agreement with finite element numerical simulations. Experimental data an...

  14. Evanescent interferometric lithography.

    Science.gov (United States)

    Blaikie, R J; McNab, S J

    2001-04-01

    Simulation results are presented to illustrate the main features of what we believe is a new photolithographic technique, evanescent interferometric lithography (EIL). The technique exploits interference between resonantly enhanced, evanescently decaying diffracted orders to create a frequency-doubled intensity pattern in the near field of a metallic diffraction grating. It is shown that the intensity in a grating's near field can be enhanced significantly compared with conventional interferometric lithography. Contrast in the interference pattern is also increased, owing to a reduction in the zeroth-order transmission near resonance. The pattern's depth of field reduces as the wavelength is increased beyond cutoff of the first-order diffracted components, and results are presented showing the trade-offs that can be made between depth of field and intensity enhancement. Examples are given for a 270-nm-period grating embedded in material with refractive index n = 1.6 and illuminated with wavelengths near 450 nm. Under these conditions it is predicted that high-intensity, high-contrast patterns with 135-nm period can be formed in photoresists more than 50 nm thick.

  15. High-power graphene mode-locked Tm/Ho co-doped fiber laser with evanescent field interaction.

    Science.gov (United States)

    Li, Xiaohui; Yu, Xuechao; Sun, Zhipei; Yan, Zhiyu; Sun, Biao; Cheng, Yuanbing; Yu, Xia; Zhang, Ying; Wang, Qi Jie

    2015-11-16

    Mid-infrared ultrafast fiber lasers are valuable for various applications, including chemical and biomedical sensing, material processing and military applications. Here, we report all-fiber high-power graphene mode-locked Tm/Ho co-doped fiber laser at long wavelength with evanescent field interaction. Ultrafast pulses up to 7.8 MHz are generated at a center wavelength of 1879.4 nm, with a pulse width of 4.7 ps. A graphene absorber integrated with a side-polished fiber can increase the damage threshold significantly. Harmonics mode-locking can be obtained till to the 21(th) harmonics at a pump power of above 500 mW. By using one stage amplifier in the anomalous dispersion regime, the laser can be amplified up to 450 mW and the narrowest pulse duration of 1.4 ps can be obtained simultaneously. Our work paves the way to graphene Tm/Ho co-doped mode-locked all-fiber master oscillator power amplifiers as potentially efficient and economic laser sources for high-power laser applications, such as special material processing and nonlinear optical studies.

  16. Mode-locked, 1.94-μm, all-fiberized laser using WS₂ based evanescent field interaction.

    Science.gov (United States)

    Jung, Minwan; Lee, Junsu; Park, June; Koo, Joonhoi; Jhon, Young Min; Lee, Ju Han

    2015-07-27

    We demonstrate the use of an all-fiberized, mode-locked 1.94 μm laser with a saturable absorption device based on a tungsten disulfide (WS2)-deposited side-polished fiber. The WS2 particles were prepared via liquid phase exfoliation (LPE) without centrifugation. A series of measurements including Raman spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) revealed that the prepared particles had thick nanostructures of more than 5 layers. The prepared saturable absorption device used the evanescent field interaction mechanism between the oscillating beam and WS2 particles and its modulation depth was measured to be ~10.9% at a wavelength of 1925 nm. Incorporating the WS2-based saturable absorption device into a thulium-holmium co-doped fiber ring cavity, stable mode-locked pulses with a temporal width of ~1.3 ps at a repetition rate of 34.8 MHz were readily obtained at a wavelength of 1941 nm. The results of this experiment confirm that WS2 can be used as an effective broadband saturable absorption material that is suitable to passively generate pulses at 2 μm wavelengths.

  17. Evaluating a novel application of optical fibre evanescent field absorbance: rapid measurement of red colour in winegrape homogenates

    Science.gov (United States)

    Lye, Peter G.; Bradbury, Ronald; Lamb, David W.

    Silica optical fibres were used to measure colour (mg anthocyanin/g fresh berry weight) in samples of red wine grape homogenates via optical Fibre Evanescent Field Absorbance (FEFA). Colour measurements from 126 samples of grape homogenate were compared against the standard industry spectrophotometric reference method that involves chemical extraction and subsequent optical absorption measurements of clarified samples at 520 nm. FEFA absorbance on homogenates at 520 nm (FEFA520h) was correlated with the industry reference method measurements of colour (R2 = 0.46, n = 126). Using a simple regression equation colour could be predicted with a standard error of cross-validation (SECV) of 0.21 mg/g, with a range of 0.6 to 2.2 mg anthocyanin/g and a standard deviation of 0.33 mg/g. With a Ratio of Performance Deviation (RPD) of 1.6, the technique when utilizing only a single detection wavelength, is not robust enough to apply in a diagnostic sense, however the results do demonstrate the potential of the FEFA method as a fast and low-cost assay of colour in homogenized samples.

  18. Measuring nanolayer profiles of various materials by evanescent light technique.

    Science.gov (United States)

    Mirchin, Nina; Apter, Boris; Lapsker, Igor; Fogel, V; Gorodetsky, Uri; Popescu, Simona A; Peled, Aaron; Popescu-Pelin, Gianina; Dorcioman, Gabriela; Duta, Liviu; Popescu, Andrei; Mihailescu, Ion N

    2012-03-01

    The evanescent light photon extraction efficiency of insulator, semiconductor and conductor amorphous nanolayers deposited on glass waveguides was evaluated from Differential Evanescent Light Intensity measurements. The Differential Evanescent Light Intensity technique uses the evanescent field scattered by the deposited nanolayer, enabling nanometer thickness profiling due to the high inherent dark background contrast. The results show that the effective evanescent photon penetration depth increases from metal to semiconductor and then to insulating layers, establishing thus the effective photon-material interaction length for the various materials classes.

  19. A Study of the Flow Field Surrounding Interacting Line Fires

    Directory of Open Access Journals (Sweden)

    Trevor Maynard

    2016-01-01

    Full Text Available The interaction of converging fires often leads to significant changes in fire behavior, including increased flame length, angle, and intensity. In this paper, the fluid mechanics of two adjacent line fires are studied both theoretically and experimentally. A simple potential flow model is used to explain the tilting of interacting flames towards each other, which results from a momentum imbalance triggered by fire geometry. The model was validated by measuring the velocity field surrounding stationary alcohol pool fires. The flow field was seeded with high-contrast colored smoke, and the motion of smoke structures was analyzed using a cross-correlation optical flow technique. The measured velocities and flame angles are found to compare reasonably with the predicted values, and an analogy between merging fires and wind-blown flames is proposed.

  20. Wave rectification in plasma sheaths surrounding electric field antennas

    Science.gov (United States)

    Boehm, M. H.; Carlson, C. W.; Mcfadden, J. P.; Clemmons, J. H.; Ergun, R. E.; Mozer, F. S.

    1994-01-01

    Combined measurements of Langmuir or broadband whistler wave intensity and lower-frequency electric field waveforms, all at 10-microsecond time resolution, were made on several recent sounding rockets in the auroral ionosphere. It is found that Langmuir and whistler waves are partically rectified in the plasma sheaths surrounding the payload and the spheres used as antennas. This sheath rectification occurs whenever the high frequency (HF) potential across the sheath becomes of the same order as the electron temperature or higher, for wave frequencies near or above the ion plasma frequency. This rectification can introduce false low-frequency waves into measurements of electric field spectra when strong high-frequency waves are present. Second harmonic signals are also generated, although at much lower levels. The effect occurs in many different plasma conditions, primarily producing false waves at frequencies that are low enough for the antenna coupling to the plasma to be resistive.

  1. Evanescent waves in optics an introduction to plasmonics

    CERN Document Server

    Bertolotti, Mario; M Guzman, Angela

    2017-01-01

    This monograph provides an introductory discussion of evanescent waves and plasmons, describes their properties and uses, and shows how they are fundamental when operating with nanoscale optics. Far field optics is not suitable for the design, description, and operation of devices at this nanometre scale. Instead one must work with models based on near-field optics and surface evanescent waves. The new discipline of plasmonics has grown to encompass the generation and application of plasmons both as a travelling excitation in a nanostructure and as a stationary enhancement of the electrical field near metal nanosurfaces. The book begins with a brief review of the basic concepts of electromagnetism, then introduces evanescent waves through reflection and refraction, and shows how they appear in diffraction problems, before discussing the role that they play in optical waveguides and sensors. The application of evanescent waves in super-resolution devices is briefly presented, before plasmons are introduced. Th...

  2. Glycan profiling analysis using evanescent-field fluorescence-assisted lectin array: Importance of sugar recognition for cellular uptake of exosomes from mesenchymal stem cells.

    Science.gov (United States)

    Shimoda, Asako; Tahara, Yoshiro; Sawada, Shin-Ichi; Sasaki, Yoshihiro; Akiyoshi, Kazunari

    2017-09-23

    Studies involving the functional analysis of exosomal contents including proteins, DNA, and RNA have been reported. Most membrane proteins and lipids are glycosylated, which controls their physical properties and functions, but little is known about glycans on exosomes owing to the difficulty of analysing them. To shed light on these issues, we collected exosomes from mesenchymal stem cells (MSCs) derived from human adipose tissue for glycan profiling using evanescent-field fluorescence-assisted lectin array as well as analysis of their uptake in vivo. Initial analyses showed that the mean diameter of the collected exosomes was 178 nm and they presented with typical exosomal and MSC markers. Regarding the glycan profiling, exosomes interacted more strongly than the membrane of the original MSCs did with a range of lectins, especially sialic acid-binding lectins. The findings also showed that cellular exosome uptake involved recognition by HeLa cell-surface-bound sialic acid-binding immunoglobulin (Ig)-like lectins (siglecs). Confirming this siglec-related uptake, in vivo experiments involving subcutaneous injection of the fluorescently labelled exosomes into mice showed their transport into lymph nodes and internalization by antigen-presenting cells, particularly those expressing CD11b. Closer analysis revealed the colocalization of the exosomes with siglecs, indicating their involvement in the uptake. These findings provide us with an improved understanding of the importance of exosomal transport and targeting in relation to glycans on exosomal surfaces, potentially enabling us to standardize exosomes when using them for therapeutic purposes. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Analytical scanning evanescent microwave microscope and control stage

    Science.gov (United States)

    Xiang, Xiao-Dong; Gao, Chen; Duewer, Fred; Yang, Hai Tao; Lu, Yalin

    2009-06-23

    A scanning evanescent microwave microscope (SEMM) that uses near-field evanescent electromagnetic waves to probe sample properties is disclosed. The SEMM is capable of high resolution imaging and quantitative measurements of the electrical properties of the sample. The SEMM has the ability to map dielectric constant, loss tangent, conductivity, electrical impedance, and other electrical parameters of materials. Such properties are then used to provide distance control over a wide range, from to microns to nanometers, over dielectric and conductive samples for a scanned evanescent microwave probe, which enable quantitative non-contact and submicron spatial resolution topographic and electrical impedance profiling of dielectric, nonlinear dielectric and conductive materials. The invention also allows quantitative estimation of microwave impedance using signals obtained by the scanned evanescent microwave probe and quasistatic approximation modeling. The SEMM can be used to measure electrical properties of both dielectric and electrically conducting materials.

  4. Surround modulation characteristics of local field potential and spiking activity in primary visual cortex of cat.

    Science.gov (United States)

    Zhang, Li; Li, Bing

    2013-01-01

    In primary visual cortex, spiking activity that evoked by stimulus confined in receptive field can be modulated by surround stimulus. This center-surround interaction is hypothesized to be the basis of visual feature integration and segregation. Spiking output has been extensively reported to be surround suppressive. However, less is known about the modulation properties of the local field potential (LFP), which generally reflects synaptic inputs. We simultaneously recorded spiking activity and LFP in the area 17 of anesthetized cats to examine and compare their modulation characteristics. When the stimulus went beyond the classical receptive field, LFP exhibited decreased power along the gamma band (30-100 Hz) in most of our recording sites. Further investigation revealed that suppression of the LFP gamma mean power (gLFP) depended on the angle between the center and surround orientations. The strongest suppression was induced when center and surround orientations were parallel. Moreover, the surround influence of the gLFP exhibited an asymmetric spatial organization. These results demonstrate that the gLFP has similar but not identical surround modulation properties, as compared to the spiking activity. The spatiotemporal integration of LFP implies that the oscillation and synchronization of local synaptic inputs may have important functions in surround modulation.

  5. Evanescent excitation and emission in fluorescence microscopy.

    Science.gov (United States)

    Axelrod, Daniel

    2013-04-02

    Evanescent light-light that does not propagate but instead decays in intensity over a subwavelength distance-appears in both excitation (as in total internal reflection) and emission (as in near-field imaging) forms in fluorescence microscopy. This review describes the physical connection between these two forms as a consequence of geometrical squeezing of wavefronts, and describes newly established or speculative applications and combinations of the two. In particular, each can be used in analogous ways to produce surface-selective images, to examine the thickness and refractive index of films (such as lipid multilayers or protein layers) on solid supports, and to measure the absolute distance of a fluorophore to a surface. In combination, the two forms can further increase selectivity and reduce background scattering in surface images. The polarization properties of each lead to more sensitive and accurate measures of fluorophore orientation and membrane micromorphology. The phase properties of the evanescent excitation lead to a method of creating a submicroscopic area of total internal reflection illumination or enhanced-resolution structured illumination. Analogously, the phase properties of evanescent emission lead to a method of producing a smaller point spread function, in a technique called virtual supercritical angle fluorescence. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  6. Delayed maturation of receptive field center/surround mechanisms in V2

    OpenAIRE

    Zhang, Bin; Zheng, Jianghe; Watanabe, Ichiro; Maruko, Ichiro; Bi, Hua; Smith, Earl L.; Chino, Yuzo

    2005-01-01

    Neurons in the adult visual cortex are capable of integrating signals over a large area that surrounds their classic receptive field (RF), and this ability of cortical neurons is thought to be intimately involved in perceptual binding. It is not known, however, at what age these long-range signal interactions emerge. Here, we report that qualitatively adult-like center/surround interactions are already present in the primary visual cortex as early as postnatal day 14 in macaque monkeys. Howev...

  7. Music mixes for comparison of wave field synthesis, surround, and stereo

    OpenAIRE

    Hold, Christoph; Wierstorf, Hagen

    2016-01-01

    Four different music mixes are provided in the form of loudspeaker driving signals. Each mix was produced for wave field synthesis, surround, and stereo by the same mixing engineer. This allows a direct comparison of the different reproduction methods in listening tests.

  8. Delayed maturation of receptive field center/surround mechanisms in V2.

    Science.gov (United States)

    Zhang, Bin; Zheng, Jianghe; Watanabe, Ichiro; Maruko, Ichiro; Bi, Hua; Smith, Earl L; Chino, Yuzo

    2005-04-19

    Neurons in the adult visual cortex are capable of integrating signals over a large area that surrounds their classic receptive field (RF), and this ability of cortical neurons is thought to be intimately involved in perceptual binding. It is not known, however, at what age these long-range signal interactions emerge. Here, we report that qualitatively adult-like center/surround interactions are already present in the primary visual cortex as early as postnatal day 14 in macaque monkeys. However, the RF surrounds of visual area 2 (V2) neurons were largely absent until 4 weeks of age and, as late as 8 weeks of age, center/surround signal interactions in V2 neurons were immature. Our results suggest that the cortical circuits underlying the RF center/surround of individual neurons mature considerably later in V2 than in the primary visual cortex and give critical evidence for the hypothesis that the functional maturation of the primate visual brain proceeds in a hierarchical manner.

  9. Perfluorinated Plastic Optical Fiber Tapers for Evanescent Wave Sensing

    Directory of Open Access Journals (Sweden)

    Romeo Bernini

    2009-12-01

    Full Text Available In this work we describe the fabrication and the characterization of perfluorinated plastic-cladded optical fiber tapers. The heat-and-pull procedure has been used to fabricate symmetric tapers. Devices with different taper ratio have been produced and the repeatability of the process has been verified. The very low refractive indexes of the core-cladding perfluorinated polymers (n = 1.35–1.34 permit a strong enhancement of the evanescent wave power fraction in aqueous environments (n = 1.33, making them very attractive for evanescent wave sensing. The tapers have been characterized carrying out evanescent field absorbance measurements with different concentrations of methylene blue in water and fluorescence collection measurements in an aqueous solution containing Cy5 dye. A good sensitivity, tightly related to the low refractive index of the core-cladding materials and the geometrical profile, has been shown.

  10. Superluminal propagation of evanescent modes as a quantum effect

    Energy Technology Data Exchange (ETDEWEB)

    Xion, C.D. [School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); He, B. [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, NY 10021 (United States); Wang, Z.Y.

    2008-05-15

    Contrary to mechanical waves, the two-slit interference experiment of single photons shows that the behavior of classical electromagnetic waves corresponds to the quantum mechanical one of single photons, which is also different from the quantum-field-theory behavior such as the creations and annihilations of photons, the vacuum fluctuations, etc. Owing to a purely quantum effect, quantum tunneling particles including tunneling photons (evanescent modes) can propagate over a spacelike interval. With this picture we conclude that the superluminality of evanescent modes is a quantum mechanical rather than a classical phenomenon. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  11. Biochemical sensing application based on optical fiber evanescent wave sensor

    Science.gov (United States)

    Lv, Xiaoyi; Mo, Jiaqing; Xu, Liang; Jia, Zhenhong

    2015-08-01

    We have designed a novel evanescent field fiber optic biosensors with porous silicon dioxide cladding. The pore size of porous silicon dioxide cladding is about 100 nm in diameter. Biological molecules were immobilized to the porous silicon dioxide cladding used APTES and glutaraldehyde. Refractive index of cladding used Bruggemann's effective medium theory. We carried out simulations of changing in light intensity in optical fiber before and after chemical coupling of biomolecules. This novel optical fiber evanescent wave biosensor has a great potential in clinical chemistry for rapid and convenient determination of biological molecule.

  12. Evanescent-wave Johnson noise in small devices

    Science.gov (United States)

    Premakumar, Vickram N.; Vavilov, Maxim G.; Joynt, Robert

    2018-01-01

    In many quantum computer architectures, the qubits are in close proximity to metallic device elements. The fluctuating currents in the metal give rise to noisy electromagnetic fields that leak out into the surrounding region. These fields are known as evanescent-wave Johnson noise. The noise can decohere the qubits. We review and update the general theory of this effect for charge qubits subject to electric noise and for spin and magnetic qubits subject to magnetic noise. A mapping of the quantum-mechanical problem onto a problem in classical electrodynamics simplifies the calculations. The focus is on relatively simple geometries in which analytical calculations can be done. Results are presented for the local noise spectral density in the vicinity of cylindrical conductors such as small antennae, noise from objects that can be treated as dipoles, and noise correlation functions for several geometries. We summarize the current state of the comparison of theory with experimental results on decoherence times of qubits. Emphasis is placed on qualitative understanding of the basic concepts and phenomena.

  13. Watt-level, all-fiber, ultrafast Er/Yb-codoped double-clad fiber laser mode-locked by reduced graphene oxide interacting with a weak evanescent field

    CERN Document Server

    Gao, Lei; Li, Yujia

    2015-01-01

    We propose a Watt-level, all-fiber, ultrafast Er/Yb-codoped double-clad fiber laser passively mode-locked by reduced graphene oxide (rGO) interacting with a weak evanescent field of photonic crystal fiber (PCF). The rGO solution is filled into the cladding holes of the PCF based on total reflection, and after evaporation, the rGO flakes bear only 1/107 of the total energy in laser system, which enhances the thermal damage threshold and decreases the accumulated nonlinearity. By incorporating the saturable absorber into an Er/Yb-codoped fiber ring cavity, stable conventional soliton with a duration of 573 fs is generated, and a average output power up to 1.14 W is obtained.

  14. Evolution of scalar fields surrounding black holes on compactified constant mean curvature hypersurfaces

    CERN Document Server

    Morales, Manuel D

    2016-01-01

    Motivated by the goal for high accuracy modeling of gravitational radiation emitted by isolated systems, recently, there has been renewed interest in the numerical solution of the hyperboloidal initial value problem for Einstein's field equations in which the outer boundary of the numerical grid is placed at null infinity. In this article, we numerically implement the tetrad-based approach presented in [J.M. Bardeen, O. Sarbach, and L.T. Buchman, Phys. Rev. D 83, 104045 (2011)] for a spherically symmetric, minimally coupled, self-gravitating scalar field. When this field is massless, the evolution system reduces to a regular, first-order symmetric hyperbolic system of equations for the conformally rescaled scalar field which is coupled to a set of singular elliptic constraints for the metric coefficients. We show how to solve this system based on a numerical finite-difference approximation, obtaining stable numerical evolutions for initial black hole configurations which are surrounded by a spherical shell of...

  15. A case study of urban student and teacher experiences surrounding an outdoor environmental science field trip

    Science.gov (United States)

    Preusch, Peggy L.

    2009-12-01

    Field trips provide opportunities for students to experience many different contexts beyond the classroom, and are a popular choice of K-12 teachers in the US. Recent interest in learning that occurs at informal science education centers such as museums, zoos and aquariums has stimulated studies of the relationship between learning in and outside of schools. Although many studies focus on the teachers, the contexts, and/or the students during the field trip, only a few look at the entire process of learning by including the classroom setting before and after the field trip. This study was designed to develop understandings of the student process of learning during and surrounding an environmental science field trip to an outdoor setting. John Dewey's extensive writings on the relationship between experience and learning informed the analysis, creating a focus on active and passive elements of the experience, continuity within and across contexts, the interactive nature of the experience and the importance of subject matter. An exploration of environmental education (EE), environmental science (ES), and nature study as content revealed the complexities of the subject matter of the field trip that make its presentation problematic. An urban school was chosen to contribute to the research literature about urban student learning in outdoor environments. During the field trip, the students' active engagement with each other and the environment supported meaningful remembrances of the field trip experiences during interviews after the field trip. The students accurately described plants and animals they had observed in different habitats during the field trip. They also made connections with their home life and prior experiences in the outdoors as they discussed the field trip and drew pictures that represented their experiences. One student integrated his outdoor experience with a language arts assignment as he reflected deeply on the field trip. One implication of this

  16. No evidence for active human papillomavirus (HPV) in fields surrounding HPV-positive oropharyngeal tumors.

    Science.gov (United States)

    Rietbergen, Michelle M; Braakhuis, Boudewijn J M; Moukhtari, Nadia; Bloemena, Elisabeth; Brink, Arjen; Sie, Daoud; Ylstra, Bauke; Baatenburg de Jong, Robert J; Snijders, Peter J F; Brakenhoff, Ruud H; Leemans, C René

    2014-02-01

    Patients with human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinomas (OPSCCs) have a better prognosis than patients with HPV-negative OPSCCs. Important factors contributing to this better prognosis are relatively low numbers of local/regional recurrences (LRRs) and second primary tumors (SPTs) in patients with HPV-positive OPSCC. These low numbers may be explained in addition by the absence of a 'field cancerization' effect, which is a cause of LRRs and SPTs in patients with HPV-negative OPSCC. We aimed to detect a possible 'field effect' in patients with HPV-positive OPSCC. As HPV is involved in the early stage of carcinogenesis in OPSCCs, its presence is considered a reliable marker for the detection of such a field effect. Therefore, the presence of transcriptionally active HPV was analyzed in the mucosa surrounding HPV-positive OPSCCs. We included 20 patients who were surgically treated for an HPV-positive OPSCC in the period 2000-2006. Of each patient, the formalin-fixed paraffin-embedded tumor sample and all available resection margins were collected. In total, 97 resection margins were investigated with an average of five resection margins per tumor. All samples were analyzed for the presence of tumor and the presence of transcriptionally active HPV by HPV16-E6-mRNA detection. All tumors were HPV16-E6-mRNA positive. HPV16-E6-mRNA could be detected in the resection margins that contained tumor (n = 6). All tumor-negative resection margins (n = 91) scored negative for HPV16-E6-mRNA. In conclusion, transcriptional active HPV could not be detected in the mucosa surrounding an HPV-positive OPSCC, which suggests the absence of field effect. This observation may explain the lower number of LRRs and SPTs in HPV-positive patients. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Simultaneous measurement of 3D zooplankton trajectories and surrounding fluid velocity field in complex flows.

    Science.gov (United States)

    Adhikari, Deepak; Gemmell, Brad J; Hallberg, Michael P; Longmire, Ellen K; Buskey, Edward J

    2015-11-01

    We describe an automated, volumetric particle image velocimetry (PIV) and tracking method that measures time-resolved, 3D zooplankton trajectories and surrounding volumetric fluid velocity fields simultaneously and non-intrusively. The method is demonstrated for groups of copepods flowing past a wall-mounted cylinder. We show that copepods execute escape responses when subjected to a strain rate threshold upstream of a cylinder, but the same threshold range elicits no escape responses in the turbulent wake downstream. The method was also used to document the instantaneous slip velocity of zooplankton and the resulting differences in trajectory between zooplankton and non-inertial fluid particles in the unsteady wake flow, showing the method's capability to quantify drift for both passive and motile organisms in turbulent environments. Applications of the method extend to any group of organisms interacting with the surrounding fluid environment, where organism location, larger-scale eddies and smaller-scale fluid deformation rates can all be tracked and analyzed. © 2015. Published by The Company of Biologists Ltd.

  18. Field investigations of high stress soft surrounding rocks and deformation control

    Directory of Open Access Journals (Sweden)

    Weijian Yu

    2015-08-01

    Full Text Available Field investigations of high stress soft rock deformations show that the high stress soft rock roadway can slide with large deformation. Severe extrusion and floor heave can also be subsequently observed. The supported roadway can be locally damaged or completely fail, where the floor has a large deformation and/or is seriously damaged. The factors inducing large deformation of surrounding rocks in deep roadway are rock strengths, structure face cutting types, stress states, stress release, support patterns, and construction methods. Based on the deformation characteristics of high stress soft rock roadway, a comprehensive support scheme is proposed. The overall support technology of “step-by-step and joint, hierarchical reinforcement” for roadway is presented, and the anchor cable and bolt parameters to check the design methods are also given. Finally, the proposed comprehensive support method “bolt + metal mesh + U-steel arch + shortcrete + grouting and cable” is used in the extension section of east main haulage roadway at −850 m level of Qujiang coal mine. The 173-day monitoring results show that the average convergence of sidewalls reaches 208 mm, and the average relative convergence of roof and floor reaches 448 mm, suggesting that this kind of support technology for controlling large deformation of high stress soft surrounding rock roadway is effective.

  19. Evolution of scalar fields surrounding black holes on compactified constant mean curvature hypersurfaces

    Science.gov (United States)

    Morales, Manuel D.; Sarbach, Olivier

    2017-02-01

    Motivated by the goal for high accuracy modeling of gravitational radiation emitted by isolated systems, recently, there has been renewed interest in the numerical solution of the hyperboloidal initial value problem for Einstein's field equations in which the outer boundary of the numerical grid is placed at null infinity. In this article, we numerically implement the tetrad-based approach presented by Bardeen, Sarbach, and Buchman [Phys. Rev. D 83, 104045 (2011), 10.1103/PhysRevD.83.104045] for a spherically symmetric, minimally coupled, self-gravitating scalar field. When this field is massless, the evolution system reduces to a regular, first-order symmetric hyperbolic system of equations for the conformally rescaled scalar field which is coupled to a set of singular elliptic constraints for the metric coefficients. We show how to solve this system based on a numerical finite-difference approximation, obtaining stable numerical evolutions for initial black hole configurations which are surrounded by a spherical shell of scalar field, part of which disperses to infinity and part of which is accreted by the black hole. As a nontrivial test, we study the tail decay of the scalar field along different curves, including one along the marginally trapped tube, one describing the world line of a timelike observer at a finite radius outside the horizon, and one corresponding to a generator of null infinity. Our results are in perfect agreement with the usual power-law decay discussed in previous work. This article also contains a detailed analysis for the asymptotic behavior and regularity of the lapse, conformal factor, extrinsic curvature and the Misner-Sharp mass function along constant mean curvature slices.

  20. [Practical aspects of taking measurements of electromagnetic fields in the surrounding of overhead transmission lines].

    Science.gov (United States)

    Szuba, Marek

    2009-01-01

    Identification of electromagnetic fields in the vicinity of high voltage overhead transmission lines requires taking measurements and determining, on their basis, the maximum values of electric (Emax) and magnetic (Hmax) field strength, as well as the width of the area with electric field strength exceeding 1 kV/m. Measurements should be carried out in the places, where the distance between phase wires and the ground is smallest, and their results converted to conditions expected at the most disadvantageous parameters of the work of line in terms of their effect on the environment. This requires taking into consideration the maximum voltage of the transmission line, as well as the highest acceptable temperature of wires. In a single-circuit line, convertion of the measured values to expected maximum values of Emax and Hmax is not difficult, although it requires knowledge of cross-profiles in spans, in which measurements were taken. However, recounting the values of magnetic field strength produced by two-circuit lines creates a serious problem. Since in the majority of cases, the measurements in the surrounding of two-circuit lines are carried out at asymmetrical currents in both circuits, converting their results to symmetrical currents of the lines is practically impossible. Therefore, the results of the measurements of magnetic field strength carried out at the asymmetrical current of a two-circuit line cannot provide the basis for assessing the possibility of exceeding the allowable value of magnetic field intensity determined in the binding regulations. Such an assessment can only be done on the basis of the results of relevant calculations.

  1. PHYLOGENETIC ANALYSIS REVEALS GENETIC VARIATIONS OF DENSOVIRUS ISOLATED FROM FIELD MOSQUITOES IN BANGKOK AND SURROUNDING REGIONS.

    Science.gov (United States)

    Boonnak, Kobporn; Suttitheptumrong, Aroonroong; Jotekratok, Ubonwan; Pattanakitsakul, Sa-Nga

    2015-03-01

    Screening for densoviruses (DNVs) from Aedes, Culex and Toxorhynchites mosquitoes collected in Bangkok and surrounding regions identified two clades of Aedes DNV; Ae. aegypti DNV (AaeDNV) and Ae. albopictus DNV (AalDNV) by PCR-restriction fragment length polymorphism (PCR-RFLP). From nucleotide sequencing and phylogenetic analysis of PCR amplicons of a fragment of DNV capsid gene, these DNVs were shown to be new DNV genetic variations similar to AaeDNV. Isolation and identification of densoviruses from indigenous field mosquitoes reside in natural habitat should be helpful in monitoring the distribution of DNVs in important mosquitoes, especially Ae. aegypti and Ae. albopictus, vector for dengue and yellow fever viruses.

  2. Deformation-strain field in Sichuan and its surrounding areas based on GPS data

    Directory of Open Access Journals (Sweden)

    Fuchao Chen

    2015-05-01

    Full Text Available The strain rate in Sichuan and its surrounding areas, and the activity rate and strain rate in two block boundary fault zones were calculated according to the block movement parameters estimated using the station speed obtained from regional GPS station observation data in these areas for 2009–2011 and GPS continuous station data for 2011–2013. The movement field characteristics in these areas were analyzed with the Sichuan Basin as the reference. Results show that the principal strain rate and maximum shear strain rate of the Bayan Har block were the largest, followed by those of the Sichuan–Yunnan block and Sichuan Basin. The deep normal strain rate in the Longmenshan fault zone was compressive and large over the study period. The normal strain rate in the Xianshuihe fault zone was tensile.

  3. μ-PIV measurements of the ensemble flow fields surrounding a migrating semi-infinite bubble

    Science.gov (United States)

    Yamaguchi, Eiichiro; Smith, Bradford J.; Gaver, Donald P.

    2012-01-01

    Microscale particle image velocimetry (μ-PIV) measurements of ensemble flow fields surrounding a steadily-migrating semi-infinite bubble through the novel adaptation of a computer controlled linear motor flow control system. The system was programmed to generate a square wave velocity input in order to produce accurate constant bubble propagation repeatedly and effectively through a fused glass capillary tube. We present a novel technique for re-positioning of the coordinate axis to the bubble tip frame of reference in each instantaneous field through the analysis of the sudden change of standard deviation of centerline velocity profiles across the bubble interface. Ensemble averages were then computed in this bubble tip frame of reference. Combined fluid systems of water/air, glycerol/air, and glycerol/Si-oil were used to investigate flows comparable to computational simulations described in Smith and Gaver (2008) and to past experimental observations of interfacial shape. Fluorescent particle images were also analyzed to measure the residual film thickness trailing behind the bubble. The flow fields and film thickness agree very well with the computational simulations as well as existing experimental and analytical results. Particle accumulation and migration associated with the flow patterns near the bubble tip after long experimental durations are discussed as potential sources of error in the experimental method. PMID:23049158

  4. Combined evanescent-wave excitation and supercritical-angle fluorescence detection improves optical sectioning

    CERN Document Server

    Brunstein, Maia; Tourain, Christophe; Oheim, Martin

    2013-01-01

    Evanescent-wave microscopy achieves sub-diffraction axial sectioning by confining fluorescence excitation to a thin layer close to the cell/substrate interface. How thin this light sheet exactly is, however, is often unknown. Particularly in the popular objective-type total internal reflection fluorescence microscopy (TIRFM) configuration large deviations from the expected exponential intensity decay of the evanescent wave have been reported. Propagating, i.e., non-evanescent, excitation light diminishes the optical sectioning effect, reduces contrast and renders the quantification of TIRFM images uncertain. Here, we use a combination of azimuthal- and polar-angle beam scanning, dark-field scatter imaging, and atomic force microscopy to identify the sources of this unwanted background fluorescence excitation. We identify stray light originating from the microscope optics and the objective lens itself as the major sources of background, with minor contributions due to evanescent-wave scattering at the reflecti...

  5. Evanescent wave fluorescence biosensors: Advances of the last decade

    Science.gov (United States)

    Taitt, Chris Rowe; Anderson, George P.; Ligler, Frances S.

    2015-01-01

    Biosensor development has been a highly dynamic field of research and has progressed rapidly over the past two decades. The advances have accompanied the breakthroughs in molecular biology, nanomaterial sciences, and most importantly computers and electronics. The subfield of evanescent wave fluorescence biosensors has also matured dramatically during this time. Fundamentally, this review builds on our earlier 2005 review. While a brief mention of seminal early work will be included, this current review will focus on new technological developments as well as technology commercialized in just the last decade. Evanescent wave biosensors have found a wide array applications ranging from clinical diagnostics to biodefense to food testing; advances in those applications and more are described herein. PMID:26232145

  6. Axial Super-resolution Evanescent Wave Tomography

    CERN Document Server

    Pendharker, Sarang; Newman, Ward; Ogg, Stephen; Nazemifard, Neda; Jacob, Zubin

    2016-01-01

    Optical tomographic reconstruction of a 3D nanoscale specimen is hindered by the axial diffraction limit, which is 2-3 times worse than the focal plane resolution. We propose and experimentally demonstrate an axial super-resolution evanescent wave tomography (AxSET) method that enables the use of regular evanescent wave microscopes like Total Internal Reflection Fluorescence Microscope (TIRF) beyond surface imaging, and achieve tomographic reconstruction with axial super-resolution. Our proposed method based on Fourier reconstruction achieves axial super-resolution by extracting information from multiple sets of three-dimensional fluorescence images when the sample is illuminated by an evanescent wave. We propose a procedure to extract super-resolution features from the incremental penetration of an evanescent wave and support our theory by 1D (along the optical axis) and 3D simulations. We validate our claims by experimentally demonstrating tomographic reconstruction of microtubules in HeLa cells with an axi...

  7. Evanescent-wave mirror for ultracold diatomic polar molecules.

    Science.gov (United States)

    Kallush, S; Segev, B; Côté, R

    2005-10-14

    We describe the interaction of an ultracold diatomic polar molecule with an evanescent-wave mirror. Several features of this system are explored, such as the coupling between internal rovibrational states of the molecule and the laser field. Numerical simulations show quantum reflection and state selection under attainable physical conditions. Such molecular optics components will facilitate the manipulation and trapping of ultracold molecules, and might serve in future applications in several fields, e.g., as devices to filter and select a state for ultracold chemistry, to measure extremely low temperatures of molecules, or to manipulate states for quantum information processing.

  8. Design of novel architectures and field programmable gate arrays implementation of two dimensional gaussian surround function

    OpenAIRE

    Hanumantharaju, M. C; Gopalakrishna, M. T

    2014-01-01

    A new design and novel architecture suitable for FPGA/ASIC implementation of a 2D Gaussian surround function for image processing application is presented in this paper. The proposed scheme results in enormous savings of memory normally required for 2D Gaussian function implementation. In the present work, the Gaussian symmetric characteristics which quickly falls off toward plus/minus infinity has been used in order to save the memory. The 2D Gaussian function implementation is presented for...

  9. Nanotomography of Cell Surfaces with Evanescent Fields

    Directory of Open Access Journals (Sweden)

    Michael Wagner

    2008-01-01

    Full Text Available The technique of variable-angle total internal reflection fluorescence microscopy (TIRFM and its application to nanotomography of cell surfaces are described. Present applications include (1 3D imaging of chromosomes in their metaphase to demonstrate axial resolution in the nanometre range, (2 measurements of cell-substrate topology, which upon cholesterol depletion shows some loosening of cell-substrate contacts, and (3 measurements of cell topology upon photodynamic therapy (PDT, which demonstrate cell swelling and maintenance of focal contacts. The potential of the method for in vitro diagnostics, but also some requirements and limitations are discussed.

  10. Exploiting evanescent-wave amplification for subwavelength low-contrast particle detection

    Science.gov (United States)

    Roy, S.; Pereira, S. F.; Urbach, H. P.; Wei, Xukang; El Gawhary, O.

    2017-07-01

    The classical problem of subwavelength particle detection on a flat surface is especially challenging when the refractive index of the particle is close to that of the substrate. We demonstrate a method to improve the detection ability several times for such a situation, by enhancing the "forbidden" evanescent waves in the substrate using the principle of super-resolution with evanescent waves amplification. The working mechanism of the system and experimental validation from a design with a thin single dielectric layer is presented. The resulting system is a simple but complete example of evanescent-wave generation, amplification, and the consequent modulation of the far field. This principle can have far reaching impact in the field of particle detection in several applications ranging from contamination control to interferometric scattering microscopy for biological samples.

  11. Modeling of subthreshold characteristics of short channel junctionless cylindrical surrounding-gate nanowire metal-oxide-silicon field effect transistors

    Science.gov (United States)

    Jin, Xiaoshi; Liu, Xi; Lee, Jung-Hee; Lee, Jong-Ho

    2014-01-01

    A subthreshold model of short-channel junctionless field effect transistors with cylindrical surrounding-gate nanowire structure has been proposed. It was based on an approximated solution of two-dimensional Poisson's equation. The derivation of this model was introduced and the accuracy of the proposed models have been verified by comparison with both previous models and the SILVACO Atlas TCAD simulation results, which show good agreement.

  12. Sensitivity enhancement in evanescent optical waveguidesensors

    NARCIS (Netherlands)

    Veldhuis, G.J.; Parriaux, O.; Hoekstra, Hugo; Lambeck, Paul

    2000-01-01

    It is shown, that the sensitivity of the effective refractive index on the cladding index in evanescent optical waveguide sensors, can be larger than unity. This implies that the attenuation of a guided wave propagating in a waveguide immersed in an absorptive medium can be made larger than that of

  13. Bottle microresonator with actively stabilized evanescent coupling

    NARCIS (Netherlands)

    Junge, C.; Nickel, S.; O'Shea, D.; Rauschenbeutel, A.

    2011-01-01

    The evanescent coupling of light between a whispering-gallery-mode bottle microresonator and a subwavelength-diameter coupling fiber is actively stabilized by means of the Pound-Drever-Hall technique. We demonstrate the stabilization of a critically coupled resonator with a control bandwidth of 0.1

  14. Modeling distribution and abundance of soybean aphid in soybean fields using measurements from the surrounding landscape.

    Science.gov (United States)

    Bahlai, C A; Sikkema, S; Hallett, R H; Newman, J; Schaafsma, A W

    2010-02-01

    Soybean aphid (Aphis glycines Matsumura) is a severe pest of soybean in central North America. Outbreaks of the aphid in Ontario are often spotty in distribution, with some geographical areas affected severely and others with few or no aphid populations occurring in soybean for the duration of the season. A. glycines spend summers on soybean and overwinter on buckthorn, a shrub that is widespread in southern Ontario and is commonly found in agricultural hedgerows and at the margins of woodlots. A. glycines likely use both short distance migratory flights from buckthorn and longer distance dispersal flights in the search for acceptable summer hosts. This study aims to model colonization of soybean fields by A. glycines engaged in early-season migration from overwintering hosts. Akaike's information criterion (AIC) was used to rank numerous competing linear and probit models using field parameters to predict aphid presence, colonization, and density. The variable that best modeled aphid density in soybean fields in the early season was the ratio of buckthorn density to field area, although dramatic differences in relationships between the parameters were observed between study years. This study has important applications in predicting areas that are at elevated risk of developing economically damaging populations of soybean aphid and which may act as sources for further infestation.

  15. Investigations of Flare Gas Emissions in Taq Taq Oil Field on the Surrounding Land

    Directory of Open Access Journals (Sweden)

    Jafar A. Ali

    2014-11-01

    Full Text Available Environmental pollution caused by oil takes many different forms; one of the most damaging sources is simply the combustion of oil products, such as a well flare burn-off. This paper presents the results of a survey of the agriculture lands around the Taq Taq Oil Production Company. The aim of the survey was to determine the potential contamination caused by the gas emissions from the well flares. Taq Taq field is located in the Kurdistan Region of Iraq, 60 km north of the giant Kirkuk oil field, 85 km south-east of Erbil and 120 km north-west of Suleimani. Samples of soil were collected from several locations around the site and analyzed to determine the content of Polycyclic Aromatic Hydrocarbons PAH present. A gas chromatography linked to a mass spectrometry (GCMS machine was used for these measurements. The PAH contamination at each location of soil was determined and the 16-PAHs, as listed in the US Environmental Protection Agency (EPA documentation were investigated. The average content of total PAH in all samples of the agricultural soil was 0.654 mg·kg-1 with the concentrations ranging from 0.310 to 0.869 mg·kg-1. It was found that the PAH concentrations decreased with increasing distance from the TTOPCO oil field, indicating that pollution was evident, the area close to the field being more affected by the gas pollution.

  16. Mechanical and hydrological characterization of the near-field surrounding excavations in a geologic salt formation

    Energy Technology Data Exchange (ETDEWEB)

    Howard, Clifford L. [Sandia National Laboratories, Albuquerque, NM (United States)

    2014-09-01

    The technical basis for salt disposal of nuclear waste resides in salt’s favorable physical, mechanical and hydrological characteristics. Undisturbed salt formations are impermeable. Upon mining, the salt formation experiences damage in the near-field rock proximal to the mined opening and salt permeability increases dramatically. The volume of rock that has been altered by such damage is called the disturbed rock zone (DRZ).

  17. Assessment of electromagnetic field levels from surrounding high-tension overhead power lines for proposed land use.

    Science.gov (United States)

    Al-Bassam, E; Elumalai, A; Khan, A; Al-Awadi, L

    2016-05-01

    The surrounding outdoor environment for new development has a big effect on the indoor quality of life. The main aim of this work was to determine the suitability of the area for building new schools with reference to electromagnetic field (EMF) effects. The specific objective of this study was to detect the safe distance from the EMF posed by the high-tension overhead power lines in the vicinity of the specified area. The measurements were taken for both the electric and magnetic fields in different months in order to detect the highest EMF levels during the peak power load season. EMDEX II with E-probe and EMDEX II with Linda were used for the measurements. These instruments were all calibrated by ENERTECH Company in USA. The EMF associated with high tension transmission lines that surrounded the proposed site has to be below 0.2 μT (Italian EMF regulations are the most suitable regulations for the establishment of schools in Kuwait). The safety clearance distance from the existing 300-kV high-tension power line has been assigned as 200 m and from other existing 132-kV high-tension power line was 50 m. The proposed site with its predefined boundaries has a magnetic field below the Italian EMF regulations for the establishment of new schools.

  18. Influence of evanescent wave on birefringent microplates

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Hanson, Steen Grüner; Maksimyak, P. P.

    2017-01-01

    manifestations of optical forces, including the helicity-independent force caused by the transverse helicity-independent spin or vertical spin of a diagonally polarized wave, which was not observed and exploited up to recently. The main finding of our study consists in a direct experimental demonstration...... of the physical existence and mechanical action of this recently discovered extraordinary transverse component of the spin here arising in an evanescent light wave due to the total internal reflection of a linearly polarized probing beam with azimuthal angle 45(circle) at the interface between the birefringent...... plate and air, which is oriented perpendicularly to the wavevector of an evanescent wave and localized over the boundary of the transparent media with polarization-dependent refraction indices. (C) 2017 Optical Society of America...

  19. Evanescent escape from the dielectric ellipse

    Energy Technology Data Exchange (ETDEWEB)

    Creagh, Stephen C; White, Michael M, E-mail: stephen.creagh@nottingham.ac.u [School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom)

    2010-11-19

    The evanescent wave outside a whispering gallery mode of an elliptic dielectric cavity is described using the extension to complex phase space of the underlying family of rays. Evanescent waves outside dielectric cavities supporting whispering gallery modes are of practical importance in applications such as microlasers, wavelength filters and sensors. The elliptical case is interesting because it shares key topological features with generically deformed nonintegrable resonators but allows all the required ray data to be computed explicitly. This is in contrast to generic perturbations where natural boundaries can prevent direct computation of the required ray data for arbitrarily small deformations. It is found that while natural boundaries do intervene in the elliptical case, they do so at higher order in the short-wavelength approximations and only for sufficiently large deformations. Before natural boundaries intervene, complex WKB methods provide a good description of emission patterns.

  20. Substrate Integrated Evanescent Filters Employing Coaxial Stubs

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy

    2015-01-01

    is designed, fabricated, and tested. The filter exhibits a transmission zero due to the implemented stubs. The problem of evanescent mode filter analysis is formulated in terms of conventional network concepts. This formulation is then used for modelling of the filters. Strategies to further miniaturization...... and small height of the waveguide. In this work, one of the realization methods of evanescent mode waveguides using a single layer substrate is considered. The method is based on the use of coaxial stubs as capacitive susceptances externally connected to a SIW. A microwave filter based on these principles...... of the microwave filter are discussed. The approach is useful in applications where a sharp roll-off at the upper stop-band is required....

  1. On the propagation speed of evanescent modes

    Energy Technology Data Exchange (ETDEWEB)

    Barbero, A.P.L. [State Univ. of Campinas, Campinas (Brazil)]|[Universidad Federal Fluminense (Brazil); Hernandez Figueroa, H.E. [State Univ. of Campinas, Campinas (Brazil); Recami, E. [Istituto Nazionale di Fisica Nucleare, Milan (Italy)]|[Bergamo Univ., Bergamo (Italy). Fac. di Ingegneria]|[State Univ. of Campinas, Campinas (Brazil)

    2000-03-01

    The group velocity of evanescent waves (in undersized waveguides, for instance) was theoretically predicted, and has been experimentally verified, to be superluminal. By contrast, it is known that the precursor speed in vacuum cannot be larger than c. This paper, by computer simulations based on Maxwell equations only, shows the existence of both phenomena and verifies the actual possibility of superluminal group velocities, without violating the so-called (naive) Einstein causality.

  2. Bottle microresonator with actively stabilized evanescent coupling

    CERN Document Server

    Junge, C; O'Shea, D; Rauschenbeutel, A

    2011-01-01

    The evanescent coupling of light between a whispering-gallery-mode bottle microresonator and a sub-wavelength-diameter coupling fiber is actively stabilized by means of a Pound-Drever-Hall technique. We demonstrate the stabilization of a critically coupled resonator with a control bandwidth of 0.1 Hz, yielding a residual transmission of (9 \\pm 3) \\times 10^-3 for more than an hour. Simultaneously, the frequency of the resonator mode is actively stabilized.

  3. Evanescent Effects Can Alter Ultraviolet Divergences in Quantum Gravity without Physical Consequences

    CERN Document Server

    Bern, Zvi; Chi, Huan-Hang; Davies, Scott; Dixon, Lance; Nohle, Josh

    2015-01-01

    Evanescent operators such as the Gauss-Bonnet term have vanishing perturbative matrix elements in exactly D=4 dimensions. Similarly, evanescent fields do not propagate in D=4; a three-form field is in this class, since it is dual to a cosmological-constant contribution. In this Letter, we show that evanescent operators and fields modify the leading ultraviolet divergence in pure gravity. To analyze the divergence, we compute the two-loop identical-helicity four-graviton amplitude and determine the coefficient of the associated (non-evanescent) R^3 counterterm studied long ago by Goroff and Sagnotti. We compare two pairs of theories that are dual in D=4: gravity coupled to nothing or to three-form matter, and gravity coupled to zero-form or to two-form matter. Duff and van Nieuwenhuizen showed that, curiously, the one-loop conformal anomaly --- the coefficient of the Gauss-Bonnet operator --- changes under p-form duality transformations. We concur, and also find that the leading R^3 divergence changes under du...

  4. Temperature-independent polymer optical fiber evanescent wave sensor

    Science.gov (United States)

    Zhong, Nianbing; Liao, Qiang; Zhu, Xun; Zhao, Mingfu; Huang, Yun; Chen, Rong

    2015-06-01

    Although the numerous advantages of polymer optical fibers have been exploited in the fields of sensors and telecommunications, such fibers still experience a critical problem: the temperature dependency. Therefore, we explored the temperature-independent operation of a polymer fiber-optic evanescent wave sensor immersed in distilled water. We investigated variations in the surface morphology, deformation trajectory, refractive index, and weight of the fiber-sensing region with varying water temperature. We also examined the spectral transmission and transmitted light intensity of fibers subjected to a heating-cooling treatment. We observed that the light-transmission modes and sensitivity of the sensor were affected by changes in the surface morphology, diameter, and refractive index of the sensing region caused by changes in temperature. The transmitted light intensity of the sensor was maintained at a constant level after five cycles of the heating-cooling treatment, after which the fibers exhibited a smooth surface, low refractive index, and large fiber diameter. Consequently, we utilized the heating-cooling-treated fiber to realize a temperature-independent, U-shaped polymer fiber-optic evanescent wave sensor. The temperature independence was evaluated using glucose solutions in the range of 10 to 70 °C. The fabricated sensor showed significant temperature independence and high degree of consistency in measuring solutions.

  5. Evanescent ergosurfaces and ambipolar hyperkähler metrics

    Energy Technology Data Exchange (ETDEWEB)

    Niehoff, Benjamin E.; Reall, Harvey S. [DAMTP, Centre for Mathematical Sciences, University of Cambridge,Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2016-04-20

    A supersymmetric solution of 5d supergravity may admit an ‘evanescent ergosurface’: a timelike hypersurface such that the canonical Killing vector field is timelike everywhere except on this hypersurface. The hyperkähler ‘base space’ of such a solution is ‘ambipolar’, changing signature from (+ + + +) to (− − − −) across a hypersurface. In this paper, we determine how the hyperkähler structure must degenerate at the hypersurface in order for the 5d solution to remain smooth. This leads us to a definition of an ambipolar hyperkähler manifold which generalizes the recently-defined notion of a ‘folded’ hyperkähler manifold. We prove that such manifolds can be constructed from ‘initial’ data prescribed on the hypersurface. We present an ‘initial value’ construction of supersymmetric solutions of 5d supergravity, in which such solutions are determined by data prescribed on a timelike hypersurface, both for the generic case and for the case of an evanescent ergosurface.

  6. Sensitivity Analysis Of Evanescent Fiber Optic Sensors

    Science.gov (United States)

    Wang, Jinyu; Christensen, Douglas A.; Brynda, E.; Andrade, Joseph D.; Ives, Jeffrey T.; Lin, Jinnan

    1989-06-01

    Evanescent fiber optic sensors are being developed for remote in situ immunoassay. The single reflection total internal reflection fluorescence (TIRF) geometry can serve as a well-defined model against which evanescent waveguide devices can be compared and evaluated. This paper addresses the problem of optimizing the sensitivity of an evanescent fiber optic sensor (EFOS). Two aspects are discussed: (1) the modes of exciting laser light in the fiber have an effect on the sensor efficiency and signal-to-noise ratio; (2) in a fiber biosensor, there is generally a protein layer attached to the core surface; the thickness of the layer is at least 5nm. If the refractive index of the protein layer can be made equal to the refractive index of the core, we can get a new fiber waveguide in which the core also contains the protein layer. The fluorescent emission sources are thus inside the core region and generate the highest signal collection efficiency. We also discuss the situation when the refractive index of the protein layer is larger or smaller than that of the optical fiber core.

  7. Impact of different breathing conditions on the dose to surrounding normal structures in tangential field breast radiotherapy

    Directory of Open Access Journals (Sweden)

    Prabhakar Ramachandran

    2007-01-01

    Full Text Available Cardiac toxicity is an important concern in tangential field breast radiotherapy. In this study, the impact of three different breathing conditions on the dose to surrounding normal structures such as heart, ipsilateral lung, liver and contralateral breast has been assessed. Thirteen patients with early breast cancer who underwent conservative surgery (nine left-sided and four right-sided breast cancer patients were selected in this study. Spiral CT scans were performed for all the three breathing conditions, viz., deep inspiration breath-hold (DIBH, normal breathing phase (NB and deep expiration breath-hold (DEBH. Conventional tangential fields were placed on the 3D-CT dataset, and the parameters such as V30 (volume covered by dose> 30 Gy for heart, V20 (volume covered by dose> 20 Gy for ipsilateral lung and V50 (volume receiving> 50% of the prescription dose for heart and liver were studied. The average reduction in cardiac dose due to DIBH was 64% (range: 26.5-100% and 74% (range: 37-100% as compared to NB and DEBH respectively. For right breast cancer, DIBH resulted in excellent liver sparing. Our results indicate that in patients with breast cancer, delivering radiation in deep inspiration breath-hold condition can considerably reduce the dose to the surrounding normal structures, particularly heart and liver.

  8. Impact of different breathing conditions on the dose to surrounding normal structures in tangential field breast radiotherapy.

    Science.gov (United States)

    Prabhakar, Ramachandran; Tharmar, Ganesh; Julka, Pramod K; Rath, Goura K; Joshi, Rakesh C; Bansal, Anil K; Bisht, R K; Gopishankar, N; Pant, G S; Thulkar, S

    2007-01-01

    Cardiac toxicity is an important concern in tangential field breast radiotherapy. In this study, the impact of three different breathing conditions on the dose to surrounding normal structures such as heart, ipsilateral lung, liver and contralateral breast has been assessed. Thirteen patients with early breast cancer who underwent conservative surgery (nine left-sided and four right-sided breast cancer patients) were selected in this study. Spiral CT scans were performed for all the three breathing conditions, viz., deep inspiration breath-hold (DIBH), normal breathing phase (NB) and deep expiration breath-hold (DEBH). Conventional tangential fields were placed on the 3D-CT dataset, and the parameters such as V30 (volume covered by dose >30 Gy) for heart, V20 (volume covered by dose >20 Gy) for ipsilateral lung and V(50) (volume receiving >50% of the prescription dose) for heart and liver were studied. The average reduction in cardiac dose due to DIBH was 64% (range: 26.5-100%) and 74% (range: 37-100%) as compared to NB and DEBH respectively. For right breast cancer, DIBH resulted in excellent liver sparing. Our results indicate that in patients with breast cancer, delivering radiation in deep inspiration breath-hold condition can considerably reduce the dose to the surrounding normal structures, particularly heart and liver.

  9. Evanescent Waves Nuclear Magnetic Resonance

    DEFF Research Database (Denmark)

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order...

  10. Earthworm communities in arable fields and restored field margins, as related to management practices and surrounding landscape diversity

    NARCIS (Netherlands)

    Frazão, Joana; Goede, de Ron G.M.; Brussaard, Lijbert; Faber, Jack H.; Groot, Jeroen C.J.; Pulleman, Mirjam M.

    2017-01-01

    Agricultural intensification has negative impacts on biodiversity at spatial scales from field to landscape. Earthworms are important for soil functioning, so it is crucial to understand the responses of earthworm communities to agricultural management and land use. We aimed to: 1) investigate

  11. A Parameter Sensitivity Analysis of the Effect of Rebar Corrosion on the Stress Field in the Surrounding Concrete

    Directory of Open Access Journals (Sweden)

    Fangyuan Li

    2017-01-01

    Full Text Available Rebar corrosion results in a change in the stress field in the surrounding concrete, which in turn accelerates the deterioration of the concrete structure. In addition to the protective layer, the compressive stress under which concrete is prestressed also affects the effect of corrosion-induced rebar expansion on the stress field in the concrete. The present study simulates the effect of corrosion-induced rebar expansion on the stress field in the concrete using the finite element method (FEM by applying a virtual radial displacement to the product of corrosion-induced rebar expansion. Based on an analysis of the effect of multiple rebars on the stress field in ordinary concrete, stress distribution in the protective layer of the concrete is determined. Afterward, the locations where there is damage to the surface concrete caused by rebar corrosion are determined. After verifying the feasibility of the FEM analysis, the effect of corrosion-induced ordinary rebar expansion in a typical prestressed concrete segment is determined by analyzing the characteristics of corrosion-induced rebar expansion occurring in various prestressed concrete specimens.

  12. Evanescent-wave proton postaccelerator driven by intense THz pulse

    Directory of Open Access Journals (Sweden)

    L. Pálfalvi

    2014-03-01

    Full Text Available Hadron therapy motivates research dealing with the production of particle beams with ∼100  MeV/nucleon energy and relative energy fluctuation on the order of 1%. Laser-driven accelerators produce ion beams with only tens of MeV/nucleon energy and an extremely broad spectra. Here, a novel method is proposed for postacceleration and monochromatization of particles, leaving the laser-driven accelerator, by using intense THz pulses. It is based on further developing the idea of using the evanescent field of electromagnetic waves between a pair of dielectric crystals. Simple model calculations show that the energy of a proton bunch can be increased from 40 to 56 MeV in five stages and its initially broad energy distribution can be significantly narrowed down.

  13. Development of evanescent wave absorbance-based fibre-optic ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... Evanescent wave biosensor; U-bent fibre-optic probe; fibre-optic biosensor; evanescent wave absorbance; gold nanoparticles localized SPR biosensor; ... Department of Physics, Indian Institute of Technology Bombay, Mumbai 400 076, India; Department of Biosciences and Bioengineering, Indian Institute ...

  14. Varactor-tuned Substrate Integrated Evanescent Filter

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Acar, Öncel; Dong, Yunfeng

    Evanescent mode waveguides allow for more compact microwave component design in comparison to the traditional fundamental mode waveguide technology. Evanescent waveguides can be integrated into a dielectric substrate in order to further reduce the mass and volume. Unfortunately, traditional reali......, fabricated and tested in order to validate the developed filter models as well as the implemented realization method. The filter structure as well as its tuning are shown in Figure 1....... is considered. In contrast to other methods described in the literature, it avoids etching split ring resonators in the metal layer of the SIW. The filters presented here use varactors as tuning elements. The varactors (as well as DC decoupling circuits) are mounted on the surface of PCB bringing the lower...... metal layer of the waveguide to the top layer with metalized via holes. The present filters are analyzed using models based on impedance matrix representation. The developed models allow computationally efficient and relatively accurate prediction of the filter behavior in a wide frequency range (at...

  15. LiDAR, geophysical and field surveys at Ancient Epomanduodurum site and its surrounding country (Doubs, Eastern France)

    Science.gov (United States)

    Laplaige, Clement; Bossuet, Gilles; Thivet, Matthieu

    2010-05-01

    understand the connections, both in time and in space, between human occupation and the surrounding region, not only at the Roman period and the late Iron Age, but also during prehistoric, medieval and modern periods. In that way, we have defined a square window of 80 km², surrounding the Ancient site of Epomanduodurum This study is based on the LIDAR (Light Detection And Ranging) technology, particularly adapted for the detection and location of cultural resources (ancient fields, buried structures, graves) in forested environment and a multi-data crossing, including: - Geophysical prospecting (principally magnetic, electromagnetic and electric) - Studies of ancient maps, plans (18th and 19th) and archaeological inventories in order to spot the location of vestiges and the utilisation of former soils - Aerial and satellite picture analysis - Field walking and metal detector prospection in order to precise micro topographic anomalies obtained by LiDAR survey. We received first LiDAR results during August 2009 and the use of part of this data allows us to find new sites from different periods. We will present some results, mainly in an Ancient artisanal district built on a Latenian necropolis, on hilltop sites and also on mine plant.

  16. Enhancement of Resonant Energy Transfer Due to an Evanescent Wave from the Metal

    Energy Technology Data Exchange (ETDEWEB)

    Poudel, Amrit [Department; Chen, Xin [Center of Nanomaterials; Ratner, Mark A. [Department

    2016-02-29

    The high density of evanescent modes in the vicinity of a metal leads to enhancement of the near-field Förster resonant energy transfer (FRET) rate. We present a classical approach to calculate the FRET rate based on the dyadic Green’s function of an arbitrary dielectric environment and consider the nonlocal limit of material permittivity in the case of the metallic half-space and thin film. In a dimer system, we find that the FRET rate is enhanced due to shared evanescent photon modes bridging a donor and an acceptor. Furthermore, a general expression for the FRET rate for multimer systems is derived. The presence of a dielectric environment and the path interference effect enhance the transfer rate, depending on the combination of distance and geometry.

  17. Gas detection with evanescent-wave quartz-enhanced photoacoustic spectroscopy

    Science.gov (United States)

    Cao, Yingchun; Jin, Wei; Ho, Hoi Lut

    2012-02-01

    Evanescent-wave gas sensing with tapered optical fibers (TOFs) and quartz-enhanced photoacoustic spectroscopy (QEPAS) is reported. The evanescent field of TOFs with diameter down to sub-wavelength is utilized for photoacoustic excitation in photoacoustic spectroscopy. A quartz tuning fork (QTF) with resonant frequency about ~32.75 kHz is used to detect the generated pressure wave. A normalized noise equivalent absorption coefficient of 1.5×10-6 cm-1 W/√Hz is achieved for acetylene detection with a fiber taper with a waist diameter of 1.1 μm. It is found that QEPAS with TOFs of sub-wavelength diameters exhibit comparable sensitivities with open path QEPAS but with additional advantages of lower insertion loss, easier alignment, and multiplexing capability.

  18. Three types of crust: Inferred emplacement rates and styles of a megablocky flow field surrounding Sabancaya volcano, Peru

    Science.gov (United States)

    Gregg, T. K.; Bulmer, M.; Anderson, S. W.; Warner, N. H.; Goudy, C. L.; McColley, S.; Turner, I.

    2002-12-01

    Sabancaya volcano is a complex edifice located ~70 km NW of Arequipa, Peru. It is surrounded by a large (~64 km2 andesitic/trachyandesitic lava flow field comprising 39 identifiable lobes that were emplaced during the Holocene. Flow morphology is distinct from that observed on evolved lavas in North America, providing an important foil to these well studied examples. The Sabancaya flows are channeled, and are characterized by steep, thick (>120 m) margins. Underlying slopes range from 10° near the vent to generations, is common. Fold wavelengths and amplitudes are on the order of 25 m and 5 m, respectively. The flows are covered with angular blocks ranging in size from 40 cm to several meters. Preliminary data suggest that block-size distribution within a single lobe is more dependent on the proximity of fold crests than on distance from the vent. Fold amplitude (~5 m) suggests a minimum thickness for a ductile surface crust during emplacement; in contrast, the largest block size on the surface (>3 m) reveals the thickness of the brittley deforming surface crust. Hand-sample analyses reveal large (>>0.5 cm) plagioclase phenocrysts in a glassy, avesicular matrix with occasional cm-sized inclusions of basaltic andesite. Crystal-size distributions in the groundmass determined from samples collected along the flow length are essentially constant, suggesting that the lavas experienced little cooling during emplacement, consistent with a well insulated lava flow. Model results indicate that the flow lobe interior could have remained hot, and possibly molten, for thousands of years. Thus, the Sabancaya flows display 3 types of surface crust: a brittle, thin (3-5 m) surface layer that generated the large, angular blocks observed on the surface; a ductile, thicker (>5 m) layer that deformed during emplacement to generate the observed folds; and the thermal crust, which may have been several tens of meters thick. Morphologic, petrologic and geochemical evidence suggest that

  19. Integrated optical NIR-evanescent wave absorbance sensorfor chemical analysis.

    Science.gov (United States)

    Bürck, J; Zimmermann, B; Mayer, J; Ache, H J

    1996-01-01

    A new, long-path integrated optical (IO) sensor for the detection of non-polar organic substances is described. The sensing layer deposited on a planar multimode IO structure is built by a suitable silicone polymer with lower refractive index (RI). It acts as a hydrophobic matrix for the reversible enrichment of non-polar organic contaminants from water or air. Light from the near-infrared (NIR) range is coupled into the planar structure and the evanescent wave part of the light field penetrating into the silicone layer interacts with the enriched organic species. As a result, light is absorbed at the characteristic frequencies of the corresponding C-H, N-H or O-H overtone and combination band vibrations of the analytes. To perform evanescent field absorbance (EFA) measurements, the arc-shaped strip waveguide structure of 172 mm interaction length was adapted to a tungsten-halogen lamp and an InGaAs diode array spectrograph over gradient index fibers. Dimethyl-co-methly(phenyl)polysiloxanes with varying degrees of phenylation were prepared and used as sensitive coating materials for the IO structure. Light attenuation in the arc-shaped waveguides is high and typical insertion losses in the range of 14-18 dB were obtained. When the coated sensors were brought in contact with aqueous samples, the light transmission decreases, which is due to the formation of H(2)O micro-emulsions in the silicone superstrates. Nevertheless, after reaching constant light transmissions, absorbance spectra of aqueous trichloroethene samples were successfully collected. For gas measurements, where water cross sensitivity problems are absent, the sensitivity of the IO device for trichloroethene was tested as a function of the RI of the silicone superstrate. The slope of the TCE calibration function increases by a factor of 10 by using a poly(methylphenylsiloxane) layer with a RI of 1.449 instead of poly(dimethylsiloxane) (RI: 1.41). A comparison of the IO-EFA and an earlier developed fiber

  20. The fabrication of polymer-based evanescent optical waveguide for biosensing

    Science.gov (United States)

    Kwon, S. W.; Yang, W. S.; Lee, H. M.; Kim, W. K.; Son, G. S.; Yoon, D. H.; Lee, S.-D.; Lee, H.-Y.

    2009-03-01

    A polymer waveguide was fabricated to amplify the evanescent optical field for biosensing. The structure of waveguide was designed to propagate a normal single mode at the input and output regions for low loss beam coupling and propagation. A sensing region was formed in the middle of the waveguide to activate the evanescent mode and to induce high birefringence by depositing a thin dielectric film with a high refractive index on a single mode waveguide. A polymer waveguide with the dimensions of 7 μm-width and 2.5 μm-thickness was fabricated by photolithography and dry-etching. The active region of the TiO 2 thin film was fabricated with the dimensions of 20 mm-length, 20 nm-thickness and 2 mm-tapered tail. A polarimetric interference technique was used to evaluate the evanescent waveguide biosensor, and biomaterial such as glycerol was tested. The sensitivity of the sensor increased with increasing TiO 2 film thickness. For the fabricated waveguide with a 20 nm-thick TiO 2 film, the measured index change to the lead phase variation of 2 π was 1.8 × 10 -4.

  1. Use of analyte-modulated modal power distribution in multimode optical fibers for simultaneous single-wavelength evanescent-wave refractometry and spectrometry.

    Science.gov (United States)

    Potyrailo, R A; Ruddy, V P; Hieftje, G M

    1999-11-01

    A new method is described for the simultaneous determination of absorbance and refractive index of a sample medium. The method is based on measurement of the analyte-modulated modal power distribution (MPD) in a multimode waveguide. In turn, the MPD is quantified by the far-field spatial pattern and intensity of light, i.e., the Fraunhofer diffraction pattern (registered on a CCD camera), that emerges from a multimode optical fiber. Operationally, light that is sent down the fiber interacts with the surrounding analyte-containing medium by means of the evanescent wave at the fiber boundary. The light flux in the propagating beam and the internal reflection angles within the fiber are both affected by optical absorption connected with the analyte and by the refractive index of the analyte-containing medium. In turn, these angles are reflected in the angular divergence of the beam as it leaves the fiber. As a result, the Fraunhofer diffraction pattern of that beam yields two parameters that can, together, be used to deduce refractive index and absorbance. This MPD based detection offers important advantages over traditional evanescent-wave detection strategies which rely on recording only the total transmitted optical power or its lost fraction. First, simultaneous determination of sample refractive index and absorbance is possible at a single probe wavelength. Second, the sensitivity of refractometric and absorption measurements can be controlled simply, either by adjusting the distance between the end face of the fiber and the CCD detector or by monitoring selected modal groups at the fiber output. As a demonstration of these capabilities, several weakly absorbing solutions were examined, with refractive indices in the range from 1.3330 to 1.4553 and with absorption coefficients in the range 0-16 cm-1. The new detection strategy is likely to be important in applications in which sample coloration varies and when it is necessary to compensate for variations in the

  2. Evanescent wave induced fluorescence. A tool for quantitative interfacial analysis

    CERN Document Server

    Byrne, C D

    2000-01-01

    Time-resolved angle-resolved evanescent wave induced fluorescence spectroscopy (EWIFS) has been used, for the first time, to determine interfacial concentration distributions of molecular species. Theoretical calculations demonstrate that in dynamic systems the non-radiative fluorescence decay coefficients of molecular species are effected only in a minor way by the presence of a dielectric interface. Consequently, measurements of interfacial fluorescence decay times are used to probe variations in molecular fluorescence quantum efficiencies, caused by the presence of an interface. The understanding of these variations is combined with angle-resolved evanescent wave theory. Examination of derived theoretical models using simulated data demonstrates that angle-resolved EWIFS is capable of measuring interfacial interactions on a nanometer scale. An evanescent wave induced fluorescence spectrometer is designed and fabricated to allow the measurement of the time-integrated and time-resolved interfacial emission. ...

  3. A composite microcavity of diamond nanopillar and deformed silica microsphere with enhanced evanescent decay length

    National Research Council Canada - National Science Library

    Barbour, Russell J; Dinyari, Khodadad N; Wang, Hailin

    2010-01-01

    .... With the enhanced evanescent coupling, WGMs can in principle couple to NV centers that are 100 to 200 nm beneath the diamond pillar surface, providing a promising avenue for exploring evanescently...

  4. Dynamics of evanescent matter waves in negative-index media

    Science.gov (United States)

    Hamamda, M.; Bocvarski, V.; Perales, F.; Baudon, J.; Dutier, G.; Mainos, C.; Boustimi, M.; Ducloy, M.

    2010-11-01

    Semi-evanescent and evanescent matter waves produced by an atom wave packet impinging on a repulsive barrier can be back-refracted and reconstructed by the application of negative-index 'comoving' potential pulses. One shows that those collapses and revivals generate a matter wave confined on both sides of the barrier border ('surface matter wave') and should be observable via the retardation of atom reflection from the barrier interface. This property, joined to the possibility recently demonstrated of inducing negative refraction of atom waves, makes such potentials a matter-wave counterpart of negative-index materials or 'meta materials' well known in light optics.

  5. Evanescent wave mirror for cold atoms—A quasi-resonant case

    DEFF Research Database (Denmark)

    Fiutowski, Jacek; Bartoszek-Bober, Dobroslawa; Dohnalik, Tomasz

    2013-01-01

    The measurements of the inelastic photon scattering in the optical dipole mirror created by a quasi-resonant evanescent wave are presented. The momentum transfer between an evanescent wave and cold atoms accompanying the atom reflection are discussed for a single and double evanescent wave...

  6. Determination of the mineral stability field of evolving groundwater in the Lake Bosumtwi impact crater and surrounding areas

    Science.gov (United States)

    Loh, Yvonne Sena Akosua; Yidana, Sandow Mark; Banoeng-Yakubo, Bruce; Sakyi, Patrick Asamoah; Addai, Millicent Obeng; Asiedu, Daniel Kwadwo

    2016-09-01

    Conventional graphical techniques, mass balance geochemical modelling, and multivariate statistical methods were jointly applied to hydrogeochemical data of groundwater from the fractured rock aquifer system, and surface water in the Bosumtwi and surrounding areas to reveal evolutionary trends and the characteristics of evolving groundwater in the area. Four clusters distinguished from the Q-mode hierarchical cluster analysis (HCA) comprised three main groundwater associations and one surface water group (lake water). Although both water resources are of low mineralization (TDS principal component analyses (PCA) and other geochemical interpretations distinguished three sources of variations in the hydrochemistry. Saturation indices of possible reactive mineral phases show groundwater undersaturation relative to albite, anorthite, aragonite, barite, calcite, chlorite, chrysotile, dolomite, gypsum, k-felspar and talc, and supersaturation with respect to gibbsite, kaolinite, Ca-montmorillonite and k-mica in the area. The PCA and other geochemical interpretation identify weathering of feldspars and carbonate mineral dissolution as predominantly influencing the hydrochemistry of the groundwater. Hydrolysis of the aluminosilicates causes the groundwater to reach equilibrium with kaolinite. In addition to dissolution of silicates, the chemical composition of the lake water has been influenced by evaporation and consequent carbonate saturation.

  7. Infrared Evanescent-Absorption Spectroscopy with Chalcogenide Glass-Fibers

    OpenAIRE

    Sanghera, J S; Kung, F H; Pureza, P. C.; Nguyen, V Q; Miklos, R. E.; Aggarwal, I D

    1994-01-01

    We have used telluride glass fibers fabricated in house to measure the evanescent-absorption spectra of water, methanol, ethanol, isopropanol, acetone, ethanoic acid, hexane, and chloroform. Furthermore, detection limits of less than 2 vol. % solute were obtained for mixtures of water and methanol, ethanol, isopropanol, acetone, and ethanoic acid. Techniques to reduce the detection limits are discussed.

  8. Enhancement of evanescent waves inside media with extreme optical anisotropy

    OpenAIRE

    Belov, Pavel A.; Zhao, Yan; Hao, Yang; Parini, Clive

    2008-01-01

    Significant enhancement of evanescent spatial harmonics inside the slabs of media with extreme optical anisotropy is revealed. This phenomenon results from the pumping of standing waves and has the feature of being weakly sensitive to the material losses. Such characteristics may enable subwavelength imaging at considerable distances away from the objects.

  9. From the Somigliana waves to the evanescent waves

    Directory of Open Access Journals (Sweden)

    Pietro Caloi

    2010-02-01

    Full Text Available The Rayleigh equation has real coefficients; therefore, also the case of complex conjugated roots may be explained physically. The Author proves that the Somigliana waves may be formed for Poisson ratio values until 0.30543; for gradually less rigid media, they are missing altogether and degenerate into evanescent waves.

  10. Crustal strain fields in the surrounding areas of the Ordos Block, central China, estimated by the least-squares collocation technique

    Science.gov (United States)

    Qu, Wei; Lu, Zhong; Zhang, Ming; Zhang, Qin; Wang, Qingliang; Zhu, Wu; Qu, Feifei

    2017-05-01

    The Ordos Block and its surrounding areas play a special role in the kinetic pattern of current tectonic deformation in mainland China (East Asia). In order to better understand the recent crustal deformation and geodynamics of this region, we use GPS velocities and employ the least-squares collocation (LSC) technique to estimate the distribution of the crustal strain rate fields. We calculate the principal components of strains, such as the maximum shear strains, the plane strain gradients and the principal axes of strains. The strain fields obtained in this paper can well portray crustal deformation in the region. Our results show that the relatively higher maximum shearing strain rates are mainly distributed over region surrounding the Ordos Block, indicating these periphery areas have intense crustal activities. Indeed, these periphery areas encompass major active tectonic belts (e.g., the western edge of the Qilian Fold System, the northeastern margin of the Tibetan Plateau and the Taihang Mountain) and active grabens (e.g., Yinchuan, Hetao, Shanxi and Weihe Grabens). Significant plane strain gradients concentrated over the periphery areas of the Ordos Block, indicating that these areas have more intense crustal activity and are more prone to earthquakes. The principle strain rates also show the strain rates for the periphery of the Ordos Block are higher than other regions. The highest strain rates are along the southwestern side of the Ordos Block, indicating that the eastward extrusion dynamics from the Tibetan Plateau may still be the main cause of tectonic deformation in this region. The extensional strains are present in most parts of the Yinchuan, Hetao and Shanxi Grabens. Finally, the characteristics of the strain fields predicted by the LSC technique are discussed, and some interesting tectonic deformation information can be found through further comparison with the strain results predicted by other methods The detailed results and findings obtained

  11. Quantitative high-resolution sensing of DNA hybridization using magnetic tweezers with evanescent illumination

    Science.gov (United States)

    Oliver, Piercen M.; Park, Jin Seon; Vezenov, Dmitri

    2011-02-01

    We applied the combined approach of evanescent nanometry and force spectroscopy using magnetic tweezers to quantify the degree of hybridization of a single synthetic single-stranded DNA oligomer to a resolution approaching a single-base. In this setup, the 200 nucleotide long DNA was covalently attached to the surface of an optically transparent solid support at one end and to the surface of a superparamagnetic fluorescent microsphere (force probe) at the other end. The force was applied to the probes using an electromagnet. The end-to-end molecular distance (i.e. out-of-image-plane position of the force probe) was determined from the intensity of the probe fluorescence image observed with total-internal reflectance microscopy. An equation of state for single stranded DNA molecules under tension (extensible freely jointed chain) was used to derive the penetration depth of the evanescent field and to calibrate the magnetic properties of the force probes. The parameters of the magnetic response of the force probes obtained from the equation of state remained constant when changing the penetration depth, indicating a robust calibration procedure. The results of such a calibration were also confirmed using independently measured probe-surface distances for probes mounted onto cantilevers of an atomic force microscope. Upon hybridization of the complementary 50 nucleotide-long oligomer to the surface-bound 200-mer, the changes in the force-distance curves were consistent with the quantitative conversion of 25% of the original single-stranded DNA to its double-stranded form, which was modeled as an elastic rod. The method presented here for quantifying the hybridization state of the single DNA molecules has potential for determining the degree of hybridization of individual molecules in a single molecule array with high accuracy.We applied the combined approach of evanescent nanometry and force spectroscopy using magnetic tweezers to quantify the degree of hybridization

  12. Photonic Integration on the Hybrid Silicon Evanescent Device Platform

    Directory of Open Access Journals (Sweden)

    Hyundai Park

    2008-01-01

    Full Text Available This paper reviews the recent progress of hybrid silicon evanescent devices. The hybrid silicon evanescent device structure consists of III-V epitaxial layers transferred to silicon waveguides through a low-temperature wafer bonding process to achieve optical gain, absorption, and modulation efficiently on a silicon photonics platform. The low-temperature wafer bonding process enables fusion of two different material systems without degradation of material quality and is scalable to wafer-level bonding. Lasers, amplifiers, photodetectors, and modulators have been demonstrated with this hybrid structure and integration of these individual components for improved optical functionality is also presented. This approach provides a unique way to build photonic active devices on silicon and should allow application of silicon photonic integrated circuits to optical telecommunication and optical interconnects.

  13. Dynamics of evanescent matter waves in negative-index media

    Energy Technology Data Exchange (ETDEWEB)

    Hamamda, M; Bocvarski, V; Perales, F; Baudon, J; Dutier, G; Mainos, C; Boustimi, M; Ducloy, M, E-mail: jacques.baudon@univ-paris13.f [Laboratoire de Physique des Lasers, CNRS-UMR 7538, Universite Paris 13, 99 Av. J B Clement, 93430-Villetaneuse (France)

    2010-11-14

    Semi-evanescent and evanescent matter waves produced by an atom wave packet impinging on a repulsive barrier can be back-refracted and reconstructed by the application of negative-index 'comoving' potential pulses. One shows that those collapses and revivals generate a matter wave confined on both sides of the barrier border ('surface matter wave') and should be observable via the retardation of atom reflection from the barrier interface. This property, joined to the possibility recently demonstrated of inducing negative refraction of atom waves, makes such potentials a matter-wave counterpart of negative-index materials or 'meta materials' well known in light optics.

  14. Evanescent magnetic field effects on entropy generation at the onset ...

    Indian Academy of Sciences (India)

    The values of relaxation time of the magnetic field are chosen, so that the Lorentz force acts only in the transient state of entropy generation in natural convection. The total entropy generation was calculated for, fixed value of irreversibility distribution ratio, different relaxation time varying from 0 to 1/5 and Grashof number ...

  15. Evanescent optical trapping of nanoscale particles using slotted tapered optical fibres

    CERN Document Server

    Daly, Mark; Chormaic, Síle Nic

    2016-01-01

    While conventional optical trapping techniques can trap objects with submicron dimensions, the underlying limits imposed by the diffraction of light generally restrict their use to larger, or higher refractive index particles. As the index and diameter decrease, the trapping difficulty rapidly increases; hence, the power requirements for stable trapping become so large as to quickly denature the trapped objects in such diffraction-limited systems. Here, we present an evanescent field-based device capable of confining low index nanoscale particles using modest optical powers as low as 1.2 mW, with additional applications in the field of cold atom trapping. Our experiment uses a nanostructured optical micro-nanofibre to trap 200 nm, low-index, fluorescent particles within the structured region, thereby overcoming diffraction limitations. We analyse the trapping potential of this device both experimentally and theoretically, and show how strong optical traps are achieved with low input powers.

  16. More Gamma More Predictions: Gamma-Synchronization as a Key Mechanism for Efficient Integration of Classical Receptive Field Inputs with Surround Predictions.

    Science.gov (United States)

    Vinck, Martin; Bosman, Conrado A

    2016-01-01

    During visual stimulation, neurons in visual cortex often exhibit rhythmic and synchronous firing in the gamma-frequency (30-90 Hz) band. Whether this phenomenon plays a functional role during visual processing is not fully clear and remains heavily debated. In this article, we explore the function of gamma-synchronization in the context of predictive and efficient coding theories. These theories hold that sensory neurons utilize the statistical regularities in the natural world in order to improve the efficiency of the neural code, and to optimize the inference of the stimulus causes of the sensory data. In visual cortex, this relies on the integration of classical receptive field (CRF) data with predictions from the surround. Here we outline two main hypotheses about gamma-synchronization in visual cortex. First, we hypothesize that the precision of gamma-synchronization reflects the extent to which CRF data can be accurately predicted by the surround. Second, we hypothesize that different cortical columns synchronize to the extent that they accurately predict each other's CRF visual input. We argue that these two hypotheses can account for a large number of empirical observations made on the stimulus dependencies of gamma-synchronization. Furthermore, we show that they are consistent with the known laminar dependencies of gamma-synchronization and the spatial profile of intercolumnar gamma-synchronization, as well as the dependence of gamma-synchronization on experience and development. Based on our two main hypotheses, we outline two additional hypotheses. First, we hypothesize that the precision of gamma-synchronization shows, in general, a negative dependence on RF size. In support, we review evidence showing that gamma-synchronization decreases in strength along the visual hierarchy, and tends to be more prominent in species with small V1 RFs. Second, we hypothesize that gamma-synchronized network dynamics facilitate the emergence of spiking output that is

  17. Telomere shortening in mucosa surrounding the tumor: biosensor of field cancerization and prognostic marker of mucosal failure in head and neck squamous cell carcinoma.

    Science.gov (United States)

    Boscolo-Rizzo, Paolo; Rampazzo, Enrica; Perissinotto, Egle; Piano, Maria Assunta; Giunco, Silvia; Baboci, Lorena; Spinato, Giacomo; Spinato, Roberto; Tirelli, Giancarlo; Da Mosto, Maria Cristina; Del Mistro, Annarosa; De Rossi, Anita

    2015-05-01

    The aim of the present study was to investigate the pattern of telomere length and telomerase expression in cancer tissues and the surrounding mucosa (SM), as markers of field cancerization and clinical outcome in patients successfully treated for with head and neck squamous cell carcinoma (HNSCC). This investigation was a prospective cohort study. Telomere length and levels of telomerase reverse transcriptase (TERT) transcripts were quantified by real-time PCR in cancer tissues and SM from 139 and 90 patients with HNSCC, respectively. No correlation was found between age and telomere length in SM. Patients with short telomeres in SM had a higher risk of mucosal failure (adjusted HR=4.29). Patients with high TERT levels in cancer tissues had a higher risk of regional failure (HR=2.88), distant failure (HR=7.27), worse disease-specific survival (HR for related death=2.62) but not mucosal failure. High-risk patients having both short telomeres in SM and high levels of TERT in cancer showed a significantly lower overall survival (HR=2.46). Overall these findings suggest that telomere shortening in SM is a marker of field cancerization and may precede reactivation of TERT. Short telomeres in SM are strongly prognostic of mucosal failure, whereas TERT levels in cancer tissues increase with the aggressiveness of the disease and are prognostic of tumor spread. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Scattering of Evanescent Acoustic Waves by Regular and Irregular Objects

    Science.gov (United States)

    2006-12-01

    simulated bottom. This system of liquids is more suitable for long-term indoor use than the vegetable-oil/ glycerin system used in related studies by a...published [ 18,19]. X. Reference List for the Main Report [1] C. F. Osterhoudt, Ph. D. Thesis (in preparation). [2] P. L. Marston, Annual Report for...evanescent waves incident on targets in a simulated sediment," to be presented at the December 2006 ASA meeting. [9] C. F. Osterhoudt, Ph.D. thesis in

  19. S-matrix formulation of mesoscopic systems and evanescent modes.

    Science.gov (United States)

    Chowdhury, Sheelan Sengupta; Deo, P Singha; Jayannavar, A M; Manninen, M

    2010-01-13

    Validity of the Landauer-Buttiker formalism for studying linear transport in mesoscopic systems is well established theoretically as well as experimentally. Akkermans et al (1991 Phys. Rev. Lett. 66 76) have shown that the formalism can be extended to study thermodynamic properties like persistent currents. This extension was verified for simple one-dimensional systems. We study the applicability of Akkermans et al' s formula for quasi-one-dimensional systems with several conducting channels. In the case that all modes are propagating the formula is still valid but in the case of evanescent modes it requires reinterpretation.

  20. Evanescent waves and deaf bands in sonic crystals

    Directory of Open Access Journals (Sweden)

    V. Romero-García

    2011-12-01

    Full Text Available The properties of sonic crystals (SC are theoretically investigated in this work by solving the inverse problem k(ω using the extended plane wave expansion (EPWE. The solution of the resulting eigenvalue problem gives the complex band structure which takes into account both the propagating and the evanescent modes. In this work we show the complete mathematical formulation of the EPWE for SC and the supercell approximation for its use in both a complete SC and a SC with defects. As an example we show a novel interpretation of the deaf bands in a complete SC in good agreement with multiple scattering simulations.

  1. Analysis of specific absorption rate and internal electric field in human biological tissues surrounding an air-core coil-type transcutaneous energy transmission transformer.

    Science.gov (United States)

    Shiba, Kenji; Zulkifli, Nur Elina Binti; Ishioka, Yuji

    2017-06-01

    In this study, we analyzed the internal electric field E and specific absorption rate (SAR) of human biological tissues surrounding an air-core coil transcutaneous energy transmission transformer. Using an electromagnetic simulator, we created a model of human biological tissues consisting of a dry skin, wet skin, fat, muscle, and cortical bone. A primary coil was placed on the surface of the skin, and a secondary coil was located subcutaneously inside the body. The E and SAR values for the model representing a 34-year-old male subject were analyzed using electrical frequencies of 0.3-1.5 MHz. The transmitting power was 15 W, and the load resistance was 38.4 Ω. The results showed that the E values were below the International Commission on Non-ionizing Radiation Protection (ICNIRP) limit for the general public exposure between the frequencies of 0.9 and 1.5 MHz, and SAR values were well below the limit prescribed by the ICNIRP for the general public exposure between the frequencies of 0.3 and 1.2 MHz.

  2. Thermal transport contributed by the torsional phonons in cylindrical nanowires: Role of evanescent modes

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Zhong-Xiang [SZU-NUS Collaborative Innovation Center for Optoelectronic Science Technology, International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang 421002 (China); Zhang, Yong [Department of Mathematics and Physics, Hunan Institute of Technology, Hengyang 421002 (China); Zhang, Li-Fu, E-mail: zhanglifu68@hotmail.com [SZU-NUS Collaborative Innovation Center for Optoelectronic Science Technology, International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Fan, Dian-Yuan [SZU-NUS Collaborative Innovation Center for Optoelectronic Science Technology, International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China)

    2017-05-03

    Thermal transport contributed by the torsional phonons in cylindrical nanowires is investigated by using the isotropic elastic continuum theory. The numerical calculations for both the concavity-shaped and convexity-shaped cylindrical structures are made to reveal the role of the evanescent modes. Results show that the evanescent modes play an important role in influencing the thermal transport in such structures. For the concavity-shaped cylindrical nanowire, the evanescent modes can enhance the thermal conductance by about 20 percent, while for the convexity-shaped cylindrical nanowire, the evanescent modes can suppress the thermal conductance by 6 percent. It is also shown that the influence of the evanescent modes on the thermal conductance is strongly related to the attenuation length of the evanescent modes. A brief analysis of these results is given. - Highlights: • The evanescent modes play an important role in influencing thermal transport contributed by torsional phonons in cylindrical nanowires. • For the concavity-shaped cylindrical nanowire, the evanescent modes can enhance the thermal conductance by about 20 percent, while for the convexity-shaped cylindrical nanowire, they can suppress the thermal conductance by 6 percent.

  3. Survival probability of an immobile target in a sea of evanescent diffusive or subdiffusive traps: a fractional equation approach.

    Science.gov (United States)

    Abad, E; Yuste, S B; Lindenberg, Katja

    2012-12-01

    We calculate the survival probability of an immobile target surrounded by a sea of uncorrelated diffusive or subdiffusive evanescent traps (i.e., traps that disappear in the course of their motion). Our calculation is based on a fractional reaction-subdiffusion equation derived from a continuous time random walk model of the system. Contrary to an earlier method valid only in one dimension (d=1), the equation is applicable in any Euclidean dimension d and elucidates the interplay between anomalous subdiffusive transport, the irreversible evanescence reaction, and the dimension in which both the traps and the target are embedded. Explicit results for the survival probability of the target are obtained for a density ρ(t) of traps which decays (i) exponentially and (ii) as a power law. In the former case, the target has a finite asymptotic survival probability in all integer dimensions, whereas in the latter case there are several regimes where the values of the decay exponent for ρ(t) and the anomalous diffusion exponent of the traps determine whether or not the target has a chance of eternal survival in one, two, and three dimensions.

  4. Evanescent Wave Fiber Optic Biosensor for Salmonella Detection in Food

    Directory of Open Access Journals (Sweden)

    Arun K. Bhunia

    2009-07-01

    Full Text Available Salmonella enterica is a major food-borne pathogen of world-wide concern. Sensitive and rapid detection methods to assess product safety before retail distribution are highly desirable. Since Salmonella is most commonly associated with poultry products, an evanescent wave fiber-optic assay was developed to detect Salmonella in shell egg and chicken breast and data were compared with a time-resolved fluorescence (TRF assay. Anti-Salmonella polyclonal antibody was immobilized onto the surface of an optical fiber using biotin-avidin interactions to capture Salmonella. Alexa Fluor 647-conjugated antibody (MAb 2F-11 was used as the reporter. Detection occurred when an evanescent wave from a laser (635 nm excited the Alexa Fluor and the fluorescence was measured by a laser-spectrofluorometer at 710 nm. The biosensor was specific for Salmonella and the limit of detection was established to be 103 cfu/mL in pure culture and 104 cfu/mL with egg and chicken breast samples when spiked with 102 cfu/mL after 2–6 h of enrichment. The results indicate that the performance of the fiber-optic sensor is comparable to TRF, and can be completed in less than 8 h, providing an alternative to the current detection methods.

  5. Comparison of ASTER- and AVIRIS-Derived Mineraland Vegetation Maps of the White Horse Replacement Alunite Deposit and Surrounding Area, Marysvale Volcanic Field, Utah

    Science.gov (United States)

    Rockwell, Barnaby W.

    2009-01-01

    This report presents and compares mineral and vegetation maps of parts of the Marysvale volcanic field in west-central Utah that were published in a recent paper describing the White Horse replacement alunite deposit. Detailed, field-verified maps of the deposit were produced from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data acquired from a low-altitude Twin Otter turboprop airborne platform. Reconnaissance-level maps of surrounding areas including the central and northern Tushar Mountains, Pahvant Range, and portions of the Sevier Plateau to the east were produced from visible, near-infrared, and shortwave-infrared data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor carried aboard the Terra satellite platform. These maps are also compared to a previously published mineral map of the same area generated from AVIRIS data acquired from the high-altitude NASA ER-2 jet platform. All of the maps were generated by similar analysis methods, enabling the direct comparison of the spatial scale and mineral composition of surface geologic features that can be identified using the three types of remote sensing data. The high spatial (2-17 meter) and spectral (224 bands) resolution AVIRIS data can be used to generate detailed mineral and vegetation maps suitable for geologic and geoenvironmental studies of individual deposits, mines, and smelters. The lower spatial (15-30 meter) and spectral (9 bands) resolution ASTER data are better suited to less detailed mineralogical studies of lithology and alteration across entire hydrothermal systems and mining districts, including regional mineral resource and geoenvironmental assessments. The results presented here demonstrate that minerals and mineral mixtures can be directly identified using AVIRIS and ASTER data to elucidate spatial patterns of mineralogic zonation; AVIRIS data can enable the generation of maps with significantly greater detail and accuracy. The

  6. Evanescent channels and scattering in cylindrical nanowire heterostructures

    Science.gov (United States)

    Racec, P. N.; Racec, E. R.; Neidhardt, H.

    2009-04-01

    We investigate the scattering phenomena produced by a general finite-range nonseparable potential in a multichannel two-probe cylindrical nanowire heterostructure. The multichannel current scattering matrix is efficiently computed using the R -matrix formalism extended for cylindrical coordinates. Considering the contribution of the evanescent channels to the scattering matrix, we are able to put in evidence the specific dips in the tunneling coefficient in the case of an attractive potential. The cylindrical symmetry cancels the “selection rules” known for Cartesian coordinates. If the attractive potential is superposed over a nonuniform potential along the nanowire then resonant transmission peaks appear. We can characterize them quantitatively through the poles of the current scattering matrix. Detailed maps of the localization probability density sustain the physical interpretation of the resonances (dips and peaks). Our formalism is applied to a variety of model systems such as a quantum dot, a core/shell quantum ring, or a double barrier embedded into the nanocylinder.

  7. Chemical detection demonstrated using an evanescent wave graphene optical sensor

    Energy Technology Data Exchange (ETDEWEB)

    Maliakal, Ashok; Reith, Leslie; Cabot, Steve [LGS Innovations, 15 Vreeland Rd., Florham Park, New Jersey 07932 (United States)

    2016-04-11

    Graphene devices have been constructed on silicon mirrors, and the graphene is optically probed through an evanescent wave interaction in an attenuated total reflectance configuration using an infrared spectrometer. The graphene is electrically biased in order to tune its optical properties. Exposure of the device to the chemicals iodine and ammonia causes observable and reversible changes to graphene's optical absorption spectra in the mid to near infrared range which can be utilized for the purpose of sensing. Electrical current measurements through the graphene are made simultaneously with optical measurements allowing for simultaneous sensing using two separate detection modalities. Our current results reveal sub-ppm detection limits for iodine and approximately 100 ppm detection limits for ammonia. We have also demonstrated that this approach will work at 1.55 μm, which opens up the possibility for graphene optical sensors that leverage commercial telecom light sources.

  8. Fiber optic evanescent wave (FOEW) microbial sensor for dental application

    Science.gov (United States)

    Kishen, Anil; John, M. S.; Chen, Jun-Wei; Lim, Chu S.; Hu, Xiao; Asundi, Anand K.

    2001-10-01

    In this work a new approach based on the fiber Optic Evanescent Wave (FOEW) Spectroscopy is developed for the effective determination of dental caries activity in human saliva. The biosensor design utilized the exponentially decaying wave that extends to the lower index region of the optical fiber's core-cladding interface. In order to achieve this, a short length of the cladding is removed and the fiber core surface is coated with a porous glass medium using sol-gel technique. The acidogenic profile resulting from the Streptococcus mutans activity in the human saliva is monitored using an indicator, which was encapsulated within the porous coating. These investigations display the potential benefits of FOEW based microbial sensor to monitor caries activity in human saliva.

  9. Nanoprofiles evaluation of ZnO thin films by an evanescent light method.

    Science.gov (United States)

    Mirchin, Nina; Peled, Aaron; Duta, Liviu; Popescu, Andrei C; Dorcioman, Gabriela; Mihailescu, Ion N

    2013-10-01

    The extraction efficiency of evanescent light from ZnO nanolayers and their thickness profiles in the range of (1-105) nm was evaluated by a new microscopy technique, differential evanescent light intensity imaging method. It is based on capturing the evanescent light scattered by the layer of the material deposited on glass substrates. The analyzed ZnO films were obtained by pulsed laser deposition at 27°C and 100°C, using a nanosecond UV laser source. Copyright © 2013 Wiley Periodicals, Inc.

  10. Possibility of high performance quantum computation by superluminal evanescent photons in living systems.

    Science.gov (United States)

    Musha, Takaaki

    2009-06-01

    Penrose and Hameroff have suggested that microtubules in living systems function as quantum computers by utilizing evanescent photons. On the basis of the theorem that the evanescent photon is a superluminal particle, the possibility of high performance computation in living systems has been studied. From the theoretical analysis, it is shown that the biological brain can achieve large quantum bits computation compared with the conventional processors at room temperature.

  11. Flow injection small-volume fiber-optic pH sensor based on evanescent wave excitation and fluorescence determination.

    Science.gov (United States)

    Xiong, Yan; Huang, Ying; Ye, Zhongbin; Guan, Yafeng

    2011-05-01

    A small-volume fiber-optic pH sensor (FOEWS) based on evanescent wave excitation is developed and evaluated. The sensor is simply fabricated by inserting a decladded optical fiber into a transparent capillary tube. A microchannel between the optical fiber and the capillary inner wall was formed and acted as flow cell for solution flowing through. The pH-sensitive fluorophore of fluorescein can be excited by the evanescent wave field produced on the fiber core surface to produce emission fluorescence. pH value was then sensed by its enhancing effect on the emission fluorescence intensity. The response range of the sensor is from pH 2.09 to pH 8.85 and the linear range is from pH 3.25 to 8.85. The proposed sensor has a small detection volume of 2.5 μL and a short response time of 8 s. It has been applied to measure pH values of real water samples and was in good agreement with the results obtained by commercial pH meter. © Springer Science+Business Media, LLC 2010

  12. Multi-parameter approximation of the stress field in a cracked body in the more distant surroundings of the crack tip

    Czech Academy of Sciences Publication Activity Database

    Veselý, V.; Sobek, J.; Frantík, P.; Seitl, Stanislav

    2016-01-01

    Roč. 89, AUG (2016), s. 20-35 ISSN 0142-1123. [International Conference on Characterisation of Crack Tip Fields /3./. Urbino, 20.04.2015-22.04.2015] Institutional support: RVO:68081723 Keywords : Crack-tip fields * Williams power series * Higher order terms * Stress field reconstruction * Multi-parameter approximation accuracy Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.899, year: 2016

  13. Fabrication and evaluation of evanescent wave absorption based polyaniline-cladding modified fiber optic urea biosensor

    Science.gov (United States)

    Botewad, S. N.; Pahurkar, V. G.; Muley, G. G.

    2018-01-01

    The fabrication and study of cladding modified intrinsic fiber optic urea biosensor has been reported in the present investigation. A simple cladding modification technique was used to construct the sensor by uncladding the small portion from optical fiber. Further bare core was decorated by supportive porous, chemically and optically sensitive matrix material polyaniline (PANI) as an active cladding for enzyme residency. Enzyme-urease (Urs) was cross-linked on the active cladding region via glutaraldehyde solution. Confirmation of the prepared PANI in proper form determined by ultraviolet-visible and Fourier transform infrared spectroscopic techniques. X-ray diffraction technique was employed for nature and compatibility examination of PANI. Sensor parameters such as sensitivity, selectivity, stability and lower detection limit have been analyzed by absorption variation study in evanescent wave field. The response of prepared sensor was studied towards urea in the wide concentration range 100 nM-100 mM and confirmed its lowest detection limit as 100 nM. The stability of sensor was found 28 days with little variation in response. The fabricated sensor has not shown any response towards interference species like glucose, ascorbic acid, L-alanine, L-arginine and their combination with urea solution and hence found selective for urea solution only.

  14. Compact drain-current model for undoped cylindrical surrounding-gate metal-oxide-semiconductor field effect transistors including short channel effects

    Science.gov (United States)

    Smaani, Billel; Latreche, Saida; Iñiguez, Benjamín

    2013-12-01

    In this paper, we present a compact model for undoped short-channel cylindrical surrounding-gate MOSFETs. The drain-current model is expressed as a function of the mobile charge density, which is calculated using the analytical expressions of the surface potential and the difference between surface and center potentials model. The short-channel effects are well incorporated in the drain-current model, such as the drain-induced barrier lowering, the charge sharing effect (VT Roll-off), the subthreshold slope degradation, and the channel length modulation. A comparison of the model results with 3D numerical simulations using Silvaco Atlas-TCAD presents a good agreement from subthreshold to strong inversion regime and for different bias voltages.

  15. Practices Surrounding Event Photos

    NARCIS (Netherlands)

    Vyas, Dhaval; Nijholt, Antinus; van der Veer, Gerrit C.; Kotzé, P.; Marsden, G.; Lindgaard, G.; Wesson, J.; Winckler, M.

    Sharing photos through mobile devices has a great potential for creating shared experiences of social events between co-located as well as remote participants. In order to design novel event sharing tools, we need to develop indepth understanding of current practices surrounding these so called

  16. Disposable photonic integrated circuits for evanescent wave sensors by ultra-high volume roll-to-roll method.

    Science.gov (United States)

    Aikio, Sanna; Hiltunen, Jussi; Hiitola-Keinänen, Johanna; Hiltunen, Marianne; Kontturi, Ville; Siitonen, Samuli; Puustinen, Jarkko; Karioja, Pentti

    2016-02-08

    Flexible photonic integrated circuit technology is an emerging field expanding the usage possibilities of photonics, particularly in sensor applications, by enabling the realization of conformable devices and introduction of new alternative production methods. Here, we demonstrate that disposable polymeric photonic integrated circuit devices can be produced in lengths of hundreds of meters by ultra-high volume roll-to-roll methods on a flexible carrier. Attenuation properties of hundreds of individual devices were measured confirming that waveguides with good and repeatable performance were fabricated. We also demonstrate the applicability of the devices for the evanescent wave sensing of ambient refractive index. The production of integrated photonic devices using ultra-high volume fabrication, in a similar manner as paper is produced, may inherently expand methods of manufacturing low-cost disposable photonic integrated circuits for a wide range of sensor applications.

  17. Determination of bacterial activity by use of an evanescent-wave fiber-optic sensor

    Science.gov (United States)

    John, M. Shelly; Kishen, Anil; Sing, Lim Chu; Asundi, Anand

    2002-12-01

    A novel technique based on fiber-optic evanescent-wave spectroscopy is proposed for the detection of bacterial activity in human saliva. The sensor determines the specific concentration of Streptococcus mutans in saliva, which is a major causative factor in dental caries. In this design, one prepares the fiber-optic bacterial sensor by replacing a portion of the cladding region of a multimode fiber with a dye-encapsulated xerogel, using the solgel technique. The exponential decay of the evanescent wave at the core-cladding interface of a multimode fiber is utilized for the determination of bacterial activity in saliva. The acidogenic profile of Streptococcus mutans is estimated by use of evanescent-wave absorption spectra at various levels of bacterial activity.

  18. Study on the propagation mechanism of evanescent waves in one-dimensional periodic photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying, E-mail: chenying@ysu.edu.cn [Hebei Province Key Laboratory of Test/Measurement Technology and Instrument, School of Electrical Engineering, Yanshan University, Qinhuangdao 066004 (China); Shi, Jia; Liu, Teng; Dong, Jing [Hebei Province Key Laboratory of Test/Measurement Technology and Instrument, School of Electrical Engineering, Yanshan University, Qinhuangdao 066004 (China); Zhu, Qiguang; Chen, Weidong [Key Laboratory of Special Fiber and Fiber Sensor of Hebei Province, School of Information Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2015-10-02

    Based on the evanescent waves theory, the formation condition and propagation mechanism of evanescent waves in one-dimensional periodic photonic crystal are studied. When the incident light travels through the periodic photonic crystal at a certain angle, the optical resonance will occur in the optically denser medium, and a unique photonic local feature will occur in photonic bandgap. Furthermore, the influences on transmission performance by the photonic crystal parameters are discussed respectively. The simulation results show that the structure mentioned above can achieve the performance of high transmission and high Q value, which can provide theoretical references for photonic crystal multi-channel filters.

  19. Development of evanescent wave absorbance-based fibre-optic ...

    Indian Academy of Sciences (India)

    ... measures for disease outbreak are necessary, because of the recent biothreat, continuous monitoring of surrounding environment such as air, water and food are crucial for timely detection of harmful micro-organisms. Apart from environmental monitoring, clinical diagnosis is important, where technological developments ...

  20. Surround 3-Dimensional Scanner

    Directory of Open Access Journals (Sweden)

    Karbowski Krzysztof

    2017-06-01

    Full Text Available The paper describes original 3-dimensional structured light scanner used for medical application. Scanner kinematics is similar to the gantry mechanism of computed tomography apparatus. The unique feature of the presented scanner is a glass table for capturing image of a human body part. The scanner can acquire an object through the table. It gives the chance for surround scanning of the human body, using only one scanning head, without changing the body position. It is more cost effective scanner solution than multihead scanner configuration.

  1. Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in aqueous solutions

    DEFF Research Database (Denmark)

    Jensen, Jesper Bo Damm; Pedersen, Lars H.; Hoiby, Poul E.

    2004-01-01

    We demonstrate highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber. The air-suspended silica structures located between three neighboring air holes in the cladding...

  2. Analysis and modeling of ducted and evanescent gravity waves observed in the Hawaiian airglow

    Directory of Open Access Journals (Sweden)

    D. B. Simkhada

    2009-08-01

    Full Text Available Short-period gravity waves of especially-small horizontal scale have been observed in the Maui, Hawaii airglow. Typical small-scale gravity wave events have been investigated, and intrinsic wave propagation characteristics have been calculated from simultaneous meteor radar wind measurements. Here we report specific cases where wave structure is significantly determined by the local wind structure, and where wave characteristics are consistent with ducted or evanescent waves throughout the mesopause region. Two of the documented events, exhibiting similar airglow signatures but dramatically different propagation conditions, are selected for simple numerical modeling case studies. First, a Doppler-ducted wave trapped within relatively weak wind flow is examined. Model results confirm that the wave is propagating in the 85–95 km region, trapped weakly by evanescence above and below. Second, an evanescent wave in strong wind flow is examined. Model results suggest an opposite case from the first case study, where the wave is instead trapped above or below the mesopause region, with strong evanescence arising in the 85–95 km airglow region. Distinct differences between the characteristics of these visibly-similar wave events demonstrate the need for simultaneous observations of mesopause winds to properly assess local propagation conditions.

  3. Areas to explore surrounding the Cerro Prieto geothermal field, BC; Areas para exploracion en los alrededores del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar Dumas, Alvaro [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: alvaro.aguilar@cfe.gob.mx

    2009-07-15

    Exploration plays an important role in tapping underground natural resources-whether water, oil, natural gas or minerals. Exploratory data allow us to learn reservoir conditions, increasing probable reserves and reservoir life span. Around the Cerro Prieto geothermal field, BC, and in the Mexicali Valley in general, exploration had almost stopped but recently was resumed by the Studies Division of Comision Federal de ELectricidad (CFE)'s Gerencia de Proyectos Geotermoelectricos. The division sent technical personnel to structurally map the northern and eastern portions of Laguna Salada. The paper offers a general outline of the main zones undergoing exploratory studies-studies perhaps culminating in siting exploratory wells to locate more geothermal resources (and ultimately producing them using binary power plants). CFE also wants to site injection wells west of the current production zone, and this is covered, as well. All activities are meant to increase the productive lifespan of the geothermal reservoir. [Spanish] Cuando se trata de la explotacion de recursos naturales del subsuelo, sea agua, gas, petroleo o minerales, la exploracion juega un papel muy importante, ya que permite conocer las condiciones del yacimiento que pudieran llevar a incrementar las reservas de los recursos explotados y extender su vida util. En las zonas aledanas al campo geotermico de Cerro Prieto, BC, y en general en el Valle de Mexicali, la exploracion estaba practicamente detenida habiendose reactivado a raiz de que la Subgerencia de Estudios de la Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad (CFE) envio personal para realizar mapeos estructurales en las porciones norte y oriente de la Laguna Salada. Este trabajo presenta un panorama general de las areas prioritarias para realizar estudios exploratorios y poder programar, con mas bases, pozos exploratorios enfocados a localizar mas recursos geotermicos, inclusive para generar energia por medio

  4. Photonic waveguides evanescently coupled with single NV-centers

    OpenAIRE

    Liebermeister, Lars

    2015-01-01

    The interaction of photons with individual quantum systems is a very fundamental process in physics. Thereby, the emission rate as well as the angular emission pattern of a quantum emitter are not only a function of intrinsic properties of the emitter itself, but are also strongly modified by its surrounding. For instance, by restricting the optical modes which are allowed at the position of the dipole, the emission rate can be strongly modified and the emitted photons can be directed into sp...

  5. Local Computation of Lightness on Articulated Surrounds

    Directory of Open Access Journals (Sweden)

    Masataka Sawayama

    2012-09-01

    Full Text Available Lightness of a grey target on a uniform light (or dark surround changes by articulating the surround (articulation effect. To elucidate the processing of lightness underlying the articulation effect, the present study introduced transparency over a dark surround and investigated its effects on lightness of the target. The transparency was produced by adding a contiguous external field to the dark surround while keeping local stimulus configuration constant. Results showed that the target lightness did not change on the articulated surround when a dark transparent filter was perceived over the target, although it did on the uniform surround. These results suggest that image decomposition into a transparent filter and an underlying surface does not necessarily change lightness of the surface if the surface is articulated. Moreover, the present study revealed that articulating the surround does not always enhance lightness contrast; it can reduce the contrast effect when the target luminance is not the highest within the surround. These findings are consistent with the theoretical view that lightness perception on articulated surfaces is determined locally within a spatially limited region, and they also place a constraint on how the luminance distribution within the limited region is scaled.

  6. Multichannel tunable filter properties of 1D magnetized ternary plasma photonic crystal in the presence of evanescent wave

    Science.gov (United States)

    Awasthi, Suneet Kumar; Panda, Ranjita; Shiveshwari, Laxmi

    2017-07-01

    The multichannel tunable filter properties of one-dimensional ternary plasma photonic crystal composed of magnetized plasma and lossless dielectric have been theoretically investigated using transfer matrix method in the microwave region. The proposed filters possess 2N - 2 comb-like sharp resonant peaks also called transmission channels for N > 1 in transmission spectra in the absence and presence of an external magnetic field. Due to the coupling between evanescent waves and propagating modes in plasma and dielectric layers, respectively, 2N - 2 transmission channels are found without the addition of any defect, enabling the structure to work as a multichannel filter. Next, the filter properties can be made tunable by the application of an external magnetic field, i.e., channel frequency can either be red or blue shifted depending upon the orientation of an external magnetic field. The number of channels and their positions can also be modulated by changing the number of periods (N) and the incident angle (θo), respectively, for both transverse electric (TE) and transverse magnetic (TM) modes besides other parameters such as plasma collision frequency, thickness of the plasma layer, plasma frequency, etc.

  7. Holographic View of the Brain Memory Mechanism Based on Evanescent Superluminal Photons

    Directory of Open Access Journals (Sweden)

    Takaaki Musha

    2012-08-01

    Full Text Available D. Pollen and M. Trachtenberg proposed the holographic brain theory to help explain the existence of photographic memories in some people. They suggested that such individuals had more vivid memories because they somehow could access a very large region of their memory holograms. Hameroff suggested in his paper that cylindrical neuronal microtubule cavities, or centrioles, function as waveguides for the evanescent photons for quantum signal processing. The supposition is that microtubular structures of the brain function as a coherent fiber bundle set used to store holographic images, as would a fiber-optic holographic system. In this paper, the author proposes that superluminal photons propagating inside the microtubules via evanescent waves could provide the access needed to record or retrieve a quantum coherent entangled holographic memory.

  8. Local complex permittivity measurements of porcine skin tissue in the frequency range from 1 GHz to 15 GHz by evanescent microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kleismit, Richard A; Kozlowski, Gregory; Foy, Brent D [Department of Physics, Wright State University, 3640 Col. Glenn Hwy, Dayton, OH 45435-0001 (United States); Hull, Barbara E [Department of Biological Sciences, Wright State University, 3640 Col. Glenn Hwy, Dayton, OH 45435-0001 (United States); Kazimierczuk, Marian [Department of Electrical Engineering, Wright State University, 3640 Col. Glenn Hwy, Dayton, OH 45435-0001 (United States)], E-mail: richard.kleismit@wright.edu

    2009-02-07

    The near-field evanescent microwave microscope is based on a coaxial transmission line resonator with a silver plated tungsten tip protruding through an end-wall aperture. The sensor is used to measure the local dielectric properties of porcine skin in the frequency range from 1 GHz to 15 GHz. The dielectric property of the skin within the near field of the tip frustrates the electric field and measurably changes the transmission line's resonant frequency and quality factor (Q). The shift of the resonator's frequency and Q is measured as a function of tip-sample separation, and a quantitative relationship between the real and imaginary parts of the local dielectric constant using the method of images is established. The associated changes in quality factor image scans of subsurface tissue structure and dielectric properties of skin surface lesions are presented.

  9. Comments on Musha's theorem that an evanescent photon in the microtubule is a superluminal particle.

    Science.gov (United States)

    Hari, Syamala D

    2014-07-01

    Takaaki Musha's research of high performance quantum computation in living systems is motivated by the theories of Penrose and Hameroff that microtubules in the brain function as quantum computers, and by those of Jibu and Yasue that the quantum states of microtubules depend upon boson condensates of evanescent photons. His work is based on the assumption that the evanescent photons described by Jibu et al. are superluminal and that they are tachyons defined and discussed by well-known physicists such as Sudarshan, Feinberg and Recami. Musha gives a brief justification for the assumption and sometimes calls it a theorem. However, the assumption is not valid because Jibu et al. stated that the evanescent photons have transmission speed smaller than that of light and that their mass is real and momentum is imaginary whereas a tachyon's mass is imaginary and momentum is real. We show here that Musha's proof of the "theorem" has errors and hence his theorem/assumption is not valid. This article is not meant to further discuss any biological aspects of the brain but only to comment on the consistency of the quantum-physical aspects of earlier work by Musha et al. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Compact 3D printed module for fluorescence and label-free imaging using evanescent excitation

    Science.gov (United States)

    Pandey, Vikas; Gupta, Shalini; Elangovan, Ravikrishnan

    2018-01-01

    Total internal reflection fluorescence (TIRF) microscopy is widely used for selective excitation and high-resolution imaging of fluorophores, and more recently label-free nanosized objects, with high vertical confinement near a liquid–solid interface. Traditionally, high numerical aperture objectives (>1.4) are used to simultaneously generate evanescent waves and collect fluorescence emission signals which limits their use to small area imaging (3D module called cTIRF that can generate evanescent waves in microscope glass slides via a planar waveguide illumination. The module can be attached as a fixture to any existing optical microscope, converting it into a TIRF and enabling high signal-to-noise ratio (SNR) fluorescence imaging using any magnification objective. As the incidence optics is perpendicular to the detector, label-free evanescent scattering-based imaging of submicron objects can also be performed without using emission filters. SNR is significantly enhanced in this case as compared to cTIRF alone, as seen through our model experiments performed on latex beads and mammalian cells. Extreme flexibility and the low cost of our approach makes it scalable for limited resource settings.

  11. Signatures of evanescent transport in ballistic suspended graphene-superconductor junctions

    Science.gov (United States)

    Kumaravadivel, Piranavan; Du, Xu

    2016-04-01

    In Dirac materials, the low energy excitations behave like ultra-relativistic massless particles with linear energy dispersion. A particularly intriguing phenomenon arises with the intrinsic charge transport behavior at the Dirac point where the charge density approaches zero. In graphene, a 2-D Dirac fermion gas system, it was predicted that charge transport near the Dirac point is carried by evanescent modes, resulting in unconventional “pseudo-diffusive” charge transport even in the absence of disorder. In the past decade, experimental observation of this phenomenon remained challenging due to the presence of strong disorder in graphene devices which limits the accessibility of the low carrier density regime close enough to the Dirac point. Here we report transport measurements on ballistic suspended graphene-Niobium Josephson weak links that demonstrate a transition from ballistic to pseudo-diffusive like evanescent transport below a carrier density of ~1010 cm-2. Approaching the Dirac point, the sub-harmonic gap structures due to multiple Andreev reflections display a strong Fermi energy-dependence and become increasingly pronounced, while the normalized excess current through the superconductor-graphene interface decreases sharply. Our observations are in qualitative agreement with the long standing theoretical prediction for the emergence of evanescent transport mediated pseudo-diffusive transport in graphene.

  12. Theory of Evanescent-Wave Johnson Noise in Qubit Devices

    Science.gov (United States)

    2015-05-28

    interaction with energy splitting 2.87 GHz between ms=0 and ms=+/-1, and a fluctuating magnetic field causes transition between spin states. Devices...Delaney, Fedor Jelezko, Joerg Wrachtrup, Lloyd C.L. Hollenberg, Physics Reports 528 , 1 (2013). 8. S. Kolkowitz, A. Safira, A. A. High, R. C. Devlin

  13. Surround articulation. II. Lightness judgments.

    Science.gov (United States)

    Schirillo, J A

    1999-04-01

    It has been hypothesized that to achieve color constancy, lightness judgments require an estimate of the illuminant. A companion paper [J. Opt. Soc. Am. A 16, 793 (1999)] suggests that surround articulation enhances the likelihood that a global luminance edge will be interpreted as being due to changes in illumination rather than in reflectance. Articulation is the process of adding equally spaced incremental and decremental patches within a surround while preserving the surround's space-average luminance. Such a process results in lightness judgments that correlate perfectly with equal local ratio matches. For decrements, lightness constancy does not require articulation. These findings help explain why Arend and Goldstein [J. Opt. Soc. Am. A 4, 2281 (1987)] obtained color constancy with complex Mondrian surrounds but not with simple center surrounds.

  14. Enhancement of Afterimage Colors by Surrounding Contours

    Directory of Open Access Journals (Sweden)

    Takao Sato

    2011-05-01

    Full Text Available Presenting luminance contours surrounding the adapted areas in test phase enhances color afterimages in both duration and color appearance. The presence of surrounding contour is crucial to some color phenomenon such as van Lier's afterimage, but the contour-effect itself has not been seriously examined. In this paper, we compared the contour-effect to color afterimages and to actually colored patches to examine the nature of color information subserving color-aftereffect. In the experiment, observers were adapted for 1 sec to a small colored square (red, green, yellow, or blue presented on a gray background. Then, a test field either with or without surrounding contour was presented. Observers matched the color of a test-patch located near the afterimage to the color of afterimage. It was found that the saturation of negative afterimage was almost doubled by the presence of surrounding contours. There was no effect of luminance contrast or polarity of contours. In contrast, no enhancement of saturation by surrounding contours was observed for actually colored patches even though the colors of patches were equalized to that of afterimage without contours. This dissociation in the contour-effect demonstrates the crucial difference between the color information for aftereffects and for ordinary bottom-up color perception.

  15. Energy modulation of nonrelativistic electrons in an optical near field on a metal microslit

    OpenAIRE

    R., Ishikawa; Jongsuck, Bae; K., Mizuno

    2001-01-01

    Energy modulation of nonrelativistic electrons with a laser beam using a metal microslit as an interaction circuit has been investigated. An optical near field is induced in the proximity of the microslit by illumination of the laser beam. The electrons passing close to the slit are accelerated or decelerated by an evanescent wave contained in the near field whose phase velocity is equal to the velocity of the electrons. The electron-evanescent wave interaction in the microslit has been analy...

  16. Large-scale characterization of silicon nitride-based evanescent couplers at 532nm wavelength

    Science.gov (United States)

    Claes, Tom; Jansen, Roelof; Neutens, Pieter; Du Bois, Bert; Helin, Philippe; Severi, Simone; Van Dorpe, Pol; Deshpande, Paru; Rottenberg, Xavier

    2014-05-01

    Recently, the photonics community has a renewed attention for silicon nitride.1-3 When deposited at temperatures below 650K with plasma-enhanced chemical vapor deposition (PECVD),4 it enables photonic circuits fabricated on-top of standard complementary metaloxidesemiconductor (CMOS) electronics. Silicon nitride is moreover transparent to wavelengths that are visible to the human eye and detectable with available silicon detectors, thus offering a photonics platform for a range of applications that is not accessible with the popular silicon-on-insulator platform. However, first-time-right design of large-scale circuits for demanding specifications requires reliable models of the basic photonic building blocks, like evanescent couplers (Figure 1), components that couple power between multiple waveguides. While these models typically exist for the silicon-on-insulator platform, they still lack maturity for the emerging silicon nitride platform. Therefore, we meticulously studied silicon nitride-based evanescent couplers fabricated in our 200mm-wafer facility. We produced the structures in a silicon nitride film deposited with low-temperature PECVD, and patterned it using optical lithography at a wavelength of 193nm and reactive ion etching. We measured the performance of as much as 250 different designs at 532nm wavelength, a central wavelength in the visible range for which laser sources are widespread. For each design, we measured the progressive transmission of up-to 10 cascaded identical couplers (Figure 2(a)), yielding very accurate figures for the coupling factor (Figure 2(b)). This paper presents the trends extracted from this vast data set (Figure 3), and elaborates on the impact of the couplers bend radius and gap on its coupling factors (Figure 4 and Figure 5). We think that the large- scale characterization of evanescent couplers presented in this paper, in excellent agreement with the simulated performance of the devices, forms the basis for a component

  17. Evanescent-coupling fiber optic pollution monitoring system using etched D-shape E-core fiber

    Science.gov (United States)

    Lee, Shing M.; Yang, Changjie; Pan, Wei P.

    1996-12-01

    Surface contamination of insulators in high voltage transmission and distribution systems may lead to troublesome flashovers which interrupt service. Insulator contamination may be monitored using direct measurement of equivalent salt deposit density (ESDD), which directly relates to the flashover voltage. A fiber-optic evanescent- coupling fiber-optic ESDD monitor is presented. The use of a piece of D-shape E-core fiber as sensor head can provide a sensitive and large area ESDD monitoring system. We have demonstrated the use of D-shape fiber in monitoring ESDD on insulator surfaces. A simple process has been developed to precisely etch the D-fiber. The polarimetric and evanescent loss sensors have been investigated. The evanescent loss sensor is particularly suitable for in-situ ESDD monitoring in power transmission lines and substations.

  18. Variation on the magnetic field profiles of transmission lines for various surrounding conditions calculated by the finite element method; Variacion de los perfiles de campo magnetico en lineas de transmision en diversas condiciones del entorno calculadas mediante el metodo de elementos finitos

    Energy Technology Data Exchange (ETDEWEB)

    Ponta, Fernando; Ferreira, Fabiana

    2001-07-01

    This paper applies the finite element method for the calculation of line magnetic field transversal profile using own routine calculation. Using a real case, simulations were performed under various conditions gathering distortion elements, obtaining the field profile. By analysing these results conclusions are drawing related to the changes produced by the distortions on the magnetic field configuration and evaluations of the surrounding elements influence are evaluated.

  19. Evanescent wave sensing and absorption analysis of herbal tea floral extracts in the presence of silver metal complexes

    Science.gov (United States)

    Priyamvada, V. C.; Radhakrishnan, P.

    2017-06-01

    Fiber optic evanescent wave sensors are used for studying the absorption properties of biochemical samples. The studies give precise information regarding the actual ingredients of the samples. Recent studies report the corrosion of silver in the presence glucose dissolved in water and heated to a temperature of 70°C. Based on this report evanescent absorption studies are carried out in hibiscus herbal tea floral extracts in the presence of silver metal complexes. These studies can also lead to the evaluation of the purity of the herbal tea extract.

  20. Multi-sample immunoassay inside optical fiber capillary enabled by evanescent wave detection

    Directory of Open Access Journals (Sweden)

    Chun-Wei Wang

    2016-03-01

    Full Text Available A novel evanescent wave-based (EW microfluidic capillary fiber-optic biosensor (MCFOB has been developed using capillaries as a transducer embedded in a multichannel device to enhance the collection efficiency of the fluorescence signal. The capillary serves dual roles as a waveguide and a container, enabling more straightforward, consistent, and compact biosensor packaging compared to conventional optical fiber biosensors and microfluidic systems. In order to detect multiple samples in one device, the biosensor incorporates a polydimethysiloxane (PDMS multi-channel device, which also serves as cladding for the biosensor. In addition, this biosensor only consumes 10 μl of a sample and does not require hydrofluoric acid etching in the fabrication process. The orientation for signal collection is optimized by comparing the lateral and normal signal directions for detected glyceraldehyde 3-phosphate dehydrogenase (GAPDH. C-reactive protein (CRP is used to validate the MCFOB, and the limit of detection (LOD for CRP in the MCFOB is 1.94 ng/ml (74 pM. Moreover, the real-time measurement is demonstrated to verify that the evanescent wave is the only exciting light source in the MCFOB, which gives the potential for real-time measurement applications.

  1. Propagating and evanescent properties of double-point defects in sonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Garcia, V; Sanchez-Perez, J V [Centro de tecnologIas fisicas: Acustica, Materiales y Astrofisica, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Garcia-Raffi, L M, E-mail: virogar1@mat.upv.e [Instituto Universitario de Matematica Pura y Aplicada, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

    2010-08-15

    Complex band structures and multiple scattering theory have been used in this paper to analyze the overlapping of the evanescent waves localized in point defects in sonic crystals (SCs). The extended plane wave expansion (EPWE) with supercell approximation gives the imaginary part of the Bloch vectors that produces the decay of the localized modes inside the periodic system. Double cavities can present a coupling between the evanescent modes localized in the defect, showing a symmetric or antisymmetric mode. When point defects are close, the complex band structures reveal a splitting of the frequencies of the localized modes. Both the real part and the imaginary values of k of the localized modes in the cavities present different values for each localized mode, which gives different properties for each mode. The novel measurements, in very good agreement with analytical data, show experimental evidence of the symmetric and antisymmetric localized modes for a double-point defect in SCs. The investigation of the localization phenomena and the coupling between defects in periodic systems has fundamental importance in both pure and applied physics.

  2. A scalable pathway to nanostructured sapphire optical fiber for evanescent-field sensing and beyond

    Czech Academy of Sciences Publication Activity Database

    Chen, H.; Tian, F.; Kaňka, Jiří; Du, H.

    2015-01-01

    Roč. 106, č. 11 (2015), s. 1111021-1111025 ISSN 0003-6951 R&D Projects: GA MŠk(CZ) LH11038 Institutional support: RVO:67985882 Keywords : Aluminum coating s * Nano-structured * Silver nanoparticles Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.142, year: 2015

  3. Tuberculosis related drug-lipid interactions demonstrated by evanescent field biosensor

    CSIR Research Space (South Africa)

    Lemmer, Yolandy

    2009-08-01

    Full Text Available ; (c) synthetic protected ?-MA, dotted line, *, grey bar or (d) PC liposomes, black bar. Error bars indicate the standard deviation, n = 5 for each set. Fig.4 AmB binding to immobilized (a) MA, thin line, grey bar; (b) cholesterol, thick line, black... bar and (c) 5BMF-MA, thin line, white bar. The error bars indicate the standard deviation, n = 3 for each set. Discussion and conclusion Fig.2 Sensorgram to determine the binding of soluble AmB (1 x 10-4 M) or cholesterol liposomes to either MA...

  4. Near-field examination of perovskite-based superlenses and superlens-enhanced probe-object coupling

    Science.gov (United States)

    Kehr, S.C.; Liu, Y.M.; Martin, L.W.; Yu, P.; Gajek, M.; Yang, S.-Y.; Yang, C.-H.; Wenzel, M.T.; Jacob, R.; von Ribbeck, H.-G.; Helm, M.; Zhang, X.; Eng, L.M.; Ramesh, R.

    2011-01-01

    A planar slab of negative-index material works as a superlens with sub-diffraction-limited resolution, as propagating waves are focused and, moreover, evanescent waves are reconstructed in the image plane. Here we demonstrate a superlens for electric evanescent fields with low losses using perovskites in the mid-infrared regime. The combination of near-field microscopy with a tunable free-electron laser allows us to address precisely the polariton modes, which are critical for super-resolution imaging. We spectrally study the lateral and vertical distributions of evanescent waves around the image plane of such a lens, and achieve imaging resolution of λ/14 at the superlensing wavelength. Interestingly, at certain distances between the probe and sample surface, we observe a maximum of these evanescent fields. Comparisons with numerical simulations indicate that this maximum originates from an enhanced coupling between probe and object, which might be applicable for multifunctional circuits, infrared spectroscopy and thermal sensors. PMID:21427720

  5. IMAGING WITH MULTIMODAL ADAPTIVE-OPTICS OPTICAL COHERENCE TOMOGRAPHY IN MULTIPLE EVANESCENT WHITE DOT SYNDROME: THE STRUCTURE AND FUNCTIONAL RELATIONSHIP.

    Science.gov (United States)

    Labriola, Leanne T; Legarreta, Andrew D; Legarreta, John E; Nadler, Zach; Gallagher, Denise; Hammer, Daniel X; Ferguson, R Daniel; Iftimia, Nicusor; Wollstein, Gadi; Schuman, Joel S

    2016-01-01

    To elucidate the location of pathological changes in multiple evanescent white dot syndrome (MEWDS) with the use of multimodal adaptive optics (AO) imaging. A 5-year observational case study of a 24-year-old female with recurrent MEWDS. Full examination included history, Snellen chart visual acuity, pupil assessment, intraocular pressures, slit lamp evaluation, dilated fundoscopic exam, imaging with Fourier-domain optical coherence tomography (FD-OCT), blue-light fundus autofluorescence (FAF), fundus photography, fluorescein angiography, and adaptive-optics optical coherence tomography. Three distinct acute episodes of MEWDS occurred during the period of follow-up. Fourier-domain optical coherence tomography and adaptive-optics imaging showed disturbance in the photoreceptor outer segments (PR OS) in the posterior pole with each flare. The degree of disturbance at the photoreceptor level corresponded to size and extent of the visual field changes. All findings were transient with delineation of the photoreceptor recovery from the outer edges of the lesion inward. Hyperautofluorescence was seen during acute flares. Increase in choroidal thickness did occur with each active flare but resolved. Although changes in the choroid and RPE can be observed in MEWDS, Fourier-domain optical coherence tomography, and multimodal adaptive optics imaging localized the visually significant changes seen in this disease at the level of the photoreceptors. These transient retinal changes specifically occur at the level of the inner segment ellipsoid and OS/RPE line. En face optical coherence tomography imaging provides a detailed, yet noninvasive method for following the convalescence of MEWDS and provides insight into the structural and functional relationship of this transient inflammatory retinal disease.

  6. Visual surround suppression in schizophrenia.

    Science.gov (United States)

    Tibber, Marc S; Anderson, Elaine J; Bobin, Tracy; Antonova, Elena; Seabright, Alice; Wright, Bernice; Carlin, Patricia; Shergill, Sukhwinder S; Dakin, Steven C

    2013-01-01

    Compared to unaffected observers patients with schizophrenia (SZ) show characteristic differences in visual perception, including a reduced susceptibility to the influence of context on judgments of contrast - a manifestation of weaker surround suppression (SS). To examine the generality of this phenomenon we measured the ability of 24 individuals with SZ to judge the luminance, contrast, orientation, and size of targets embedded in contextual surrounds that would typically influence the target's appearance. Individuals with SZ demonstrated weaker SS compared to matched controls for stimuli defined by contrast or size, but not for those defined by luminance or orientation. As perceived luminance is thought to be regulated at the earliest stages of visual processing our findings are consistent with a suppression deficit that is predominantly cortical in origin. In addition, we propose that preserved orientation SS in SZ may reflect the sparing of broadly tuned mechanisms of suppression. We attempt to reconcile these data with findings from previous studies.

  7. Evanescent-wave comb spectroscopy of liquids with strongly dispersive optical fiber cavities

    Science.gov (United States)

    Avino, S.; Giorgini, A.; Salza, M.; Fabian, M.; Gagliardi, G.; De Natale, P.

    2013-05-01

    We demonstrate evanescent-wave fiber cavity-enhanced spectroscopy in the liquid phase using a near-infrared frequency comb. Exploiting strong fiber-dispersion effects, we show that liquid absorption spectra can be recorded without any external dispersive element. The fiber cavity is used both as sensor and spectrometer. The resonance modes are frequency locked to the comb teeth while the cavity photon lifetime is measured over 155 nm, from 1515 nm to 1670 nm, where absorption bands of liquid polyamines are detected as a proof of concept. Our fiber spectrometer lends itself to in situ, real-time chemical analysis in environmental monitoring, biomedical assays, and micro-opto-fluidic systems.

  8. Near-infrared fundus autofluorescence in multiple evanescent white-dot syndrome.

    Science.gov (United States)

    Battaglia Parodi, Maurizio; Iacono, Pierluigi; Falcomatà, Bruno; Bolognesi, Gianluigi; Bandello, Francesco

    2015-01-01

    To report the near-infrared fundus autofluorescence (NIR-FAF) pattern in 2 cases of multiple evanescent white-dot syndrome (MEWDS). Three consecutive patients with MEWDS underwent a complete ophthalmologic examination, including color photograph, blue-light fundus autofluorescence, NIR-FAF, fluorescein angiography, and indocyanine green angiography (ICGA). Main outcome measure was the identification of NIR-FAF pattern. Fluorescein angiography showed patchy hyperfluorescence of the whitish dots. Indocyanine green angiography showed hypofluorescent spots throughout the examination. Blue-light fundus autofluorescence disclosed a speckled pattern without extension to the foveal area, whereas NIR-AF showed several hypoautofluorescent lesions involving also the fovea, which corresponded to the whitish dots visible on biomicroscopy and to the hypofluorescent lesions detectable on ICGA. Near-infrared fundus autofluorescence is characterized by hypoautofluorescent spots corresponding to the inflammatory lesions typical of MEWDS and can be considered as a valuable noninvasive technique to diagnose and monitor patients with MEWDS.

  9. Effects of surface roughness on optical properties and sensitivity of fiber-optic evanescent wave sensors.

    Science.gov (United States)

    Zhong, Nianbing; Zhu, Xun; Liao, Qiang; Wang, Yongzhong; Chen, Rong; Sun, Yahui

    2013-06-10

    The effects of surface roughness on the light transmission properties and sensitivity of fiber-optic evanescent wave sensors are investigated. A simple method of increasing the sensitivity based on the surface roughness (pit depth δ and diameter Δ) and incident angle U(i) of light rays on the fiber input end is proposed. We discovered that as 2δ/Δ increases, the transmitted light intensity decreases, but the sensitivity initially increases and then decreases. In sensors containing fibers of various roughnesses, the sensitivity to glucose solutions reached -11.7 mW/riu at 2δ/Δ=0.32 and increased further to -15.3 mW/riu with proper adjustment of U(i).

  10. Optomechanical Transduction and Characterization of a Silica Microsphere Pendulum via Evanescent Light

    CERN Document Server

    Madugani, Ramgopal; Ward, Jonathan M; Le, Vu H; Chormaic, Síle Nic

    2015-01-01

    Transduction of the motion of a micron- or nano-sized object to an optical signal is essential for optomechanical systems. Here, we study the optical response of a cantilever-like, silica, microsphere pendulum, evanescently coupled to a ?ber taper. In this system, the optical coupling element also acts as the mechanical motion transducer and the pendulum's oscillations modulate the optical whispering gallery modes (WGMs) both dispersively and dissipatively. This unique mechanism leads to an experimentally-observable, asymmetric response function of the transduction spectrum. This phenomenon is explained by using coupled mode theory with Fourier transforms. The optomechanical transduction and its relation to the external coupling gap is experimentally investigated in depth and shows good agreement with the theory. A deep understanding of this mechanism is necessary in order to explore cooling and trapping of a micropendulum system.

  11. A microvolume molecularly imprinted polymer modified fiber-optic evanescent wave sensor for bisphenol A determination.

    Science.gov (United States)

    Xiong, Yan; Ye, Zhongbin; Xu, Jing; Liu, Yucheng; Zhang, Hanyin

    2014-04-01

    A fiber-optic evanescent wave sensor for bisphenol A (BPA) determination based on a molecularly imprinted polymer (MIP)-modified fiber column was developed. MIP film immobilized with BPA was synthesized on the fiber column, and the sensor was then constructed by inserting the optical fiber prepared into a transparent capillary. A microchannel (about 2.0 μL) formed between the fiber and the capillary acted as a flow cell. BPA can be selectively adsorbed online by the MIP film and excited to produce fluorescence by the evanescent wave produced on the fiber core surface. The conditions for BPA enrichment, elution, and fluorescence detection are discussed in detail. The analytical measurements were made at 276 nm/306 nm (λ(ex)/λ(em)), and linearity of 3 × 10(-9)-5 × 10(-6) g mL(-1) BPA, a limit of detection of 1.7 × 10(-9) g mL(-1) BPA (3σ), and a relative standard deviation of 2.4% (n = 5) were obtained. The sensor selectivity and MIP binding measurement were also evaluated. The results indicated that the selectivity and sensitivity of the proposed fiber-optic sensor could be greatly improved by using MIP as a recognition and enrichment element. Further, by modification of the sensing and detection elements on the optical fiber, the proposed sensor showed the advantages of easy fabrication and low cost. The novel sensor configuration provided a platform for monitoring other species by simply changing the light source and sensing elements. The sensor presented has been successfully applied to determine BPA released from plastic products treated at different temperatures.

  12. Far-field optical superlens.

    Science.gov (United States)

    Liu, Zhaowei; Durant, Stéphane; Lee, Hyesog; Pikus, Yuri; Fang, Nicolas; Xiong, Yi; Sun, Cheng; Zhang, Xiang

    2007-02-01

    Far-field optical lens resolution is fundamentally limited by diffraction, which typically is about half of the wavelength. This is due to the evanescent waves carrying small scale information from an object that fades away in the far field. A recently proposed superlens theory offers a new approach by surface excitation at the negative index medium. We introduce a far-field optical superlens (FSL) that is capable of imaging beyond the diffraction limit. The FSL significantly enhances the evanescent waves of an object and converts them into propagating waves that are measured in the far field. We show that a FSL can image a subwavelength object consisting of two 50 nm wide lines separated by 70 nm working at 377 nm wavelength. The optical FSL promises new potential for nanoscale imaging and lithography.

  13. Opportunity's Surroundings on Sol 1818

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends. The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view. The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock. This view is presented as a cylindrical projection with geometric seam correction.

  14. Opportunity's Surroundings on Sol 1798

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top. The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock. This view is presented as a cylindrical projection with geometric seam correction.

  15. Stationary Schrödinger equation in the semi-classical limit: numerical coupling of oscillatory and evanescent regions.

    Science.gov (United States)

    Arnold, Anton; Negulescu, Claudia

    2018-01-01

    This paper is concerned with a 1D Schrödinger scattering problem involving both oscillatory and evanescent regimes, separated by jump discontinuities in the potential function, to avoid "turning points". We derive a non-overlapping domain decomposition method to split the original problem into sub-problems on these regions, both for the continuous and afterwards for the discrete problem. Further, a hybrid WKB-based numerical method is designed for its efficient and accurate solution in the semi-classical limit: a WKB-marching method for the oscillatory regions and a FEM with WKB-basis functions in the evanescent regions. We provide a complete error analysis of this hybrid method and illustrate our convergence results by numerical tests.

  16. Development of dithizone based fibre optic evanescent wave sensor for heavy metal ion detection in aqueous environments

    Science.gov (United States)

    Bhavsar, K.; Prabhu, R.; Pollard, P.

    2013-06-01

    Detection of highly toxic heavy metal ions requires rapid, simple, sensitive and selective detection methods in the environment. Optical fibre based sensing facilitates the remote, continuous and in-situ detection approaches in the environment. Herein, we report the development of a dithizone based fibre optic sensor with a simple procedure to detect heavy metal ions in the aqueous environment using an evanescent wave sensing approach. The chromogenic ligand dithizone and its spectral specificity with metal ions has been elaborated in this work.

  17. High-sensitivity four-layer polymer fiber-optic evanescent wave sensor.

    Science.gov (United States)

    Xin, Xin; Zhong, Nianbing; Liao, Qiang; Cen, Yanyan; Wu, Ruohua; Wang, Zhengkun

    2017-05-15

    We present a novel four-layer structure consisting of bottom, second, third, and surface layers in the sensing region, for a D-shaped step-index fiber-optic evanescent wave (FOEW) sensor. To reduce the background noise, the surface of the longitudinal section in the D-shaped region is coated with a light-absorbing film. We check the morphologies of the second and surface layers, examine the refractive indices (RIs) of the third and surface layers, and analyze the composition of the surface layer. We also investigate the effects of the thicknesses and RIs of the third and surface layers and the LA film on the light transmission and sensitivity of the FOEW sensors. The results highlight the very good sensitivity of the proposed FOEW sensor with a four-layer structure, which reached -0.077 (μg/l)(-1) in the detection of the target antibody; the sensitivity of the novel FOEW sensor was 7.60 and 1.52 times better than that of a conventional sensor with a core-cladding structure and an FOEW sensor with a three-layer structure doped with GeO2. The applications of this high-sensitivity FOEW sensor can be extended to biodefense, disease diagnosis, and biomedical and biochemical analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Evanescent wave absorption sensor based on tapered multimode fiber coated with monolayer graphene film

    Science.gov (United States)

    Qiu, Hengwei; Gao, Saisai; Chen, Peixi; Li, Zhen; Liu, Xiaoyun; Zhang, Chao; Xu, Yuanyuan; Jiang, Shouzhen; Yang, Cheng; Huo, Yanyan; Yue, Weiwei

    2016-05-01

    An evanescent wave absorption (EWA) sensor based on tapered multimode fiber (TMMF) coated with monolayer graphene film for the detection of double-stranded DNA (DS-DNA) is investigated in this work. The TMMF is a silica multimode fiber (nominally at 62.5 μm), which was tapered to symmetric taper with waist diameters of ~30 μm and total length of ~3 mm. Monolayer graphene film was grown on a copper foil via chemical vapor deposition (CVD) technology and transferred onto skinless tapered fiber core via dry transfer technology. All the components of the sensor are coupled together by fusion splicer in order to eliminate the external disturbance. DS-DNA is created by the assembly of two relatively complemented oligonucleotides. The measurements are obtained by using a spectrometer in the optical wavelength range of 400-900 nm. With the increase of DS-DNA concentration, the output light intensity (OPLI) arisen an obvious attenuation. Importantly, the absorbance (A) and the DS-DNA concentrations shown a reasonable linear variation in a wide range of 5-400 μM. Through a series of comparison, the accuracy of TMMF sensor with graphene (G-TMMF) is much better than that without graphene (TMMF), which can be attributed to the molecular enrichment of graphene by π-π stacking.

  19. Portable evanescent wave fiber biosensor for highly sensitive detection of Shigella

    Science.gov (United States)

    Xiao, Rui; Rong, Zhen; Long, Feng; Liu, Qiqi

    2014-11-01

    A portable evanescent wave fiber biosensor was developed to achieve the rapid and highly sensitive detection of Shigella. In this study, a DNA probe was covalently immobilized onto fiber-optic biosensors that can hybridize with a fluorescently labeled complementary DNA. The sensitivity of detection for synthesized oligonucleotides can reach 10-10 M. The surface of the sensor can be regenerated with 0.5% sodium dodecyl sulfate solution (pH 1.9) for over 30 times without significant deterioration of performance. The total analysis time for a single sample, including the time for measurement and surface regeneration, was less than 6 min. We employed real-time polymerase chain reaction (PCR) and compared the results of both methods to investigate the actual Shigella DNA detection capability of the fiber-optic biosensor. The fiber-optic biosensor could detect as low as 102 colony-forming unit/mL Shigella. This finding was comparable with that by real-time PCR, which suggests that this method is a potential alternative to existing detection methods.

  20. Self-referencing SPR-biosensors based on penetration difference of evanescent waves.

    Science.gov (United States)

    Nizamov, Shavkat; Mirsky, Vladimir M

    2011-10-15

    SPR based biosensors register binding of analytes to the surface with immobilized receptors by measuring changes of the refractive index near this surface. An important task in the improvement of this measurement technology is a separation of signals, corresponding to the changes in the chemosensitive layer, from undesired contributions of bulk phase, for example, due to fluctuations of temperature, concentrations of solutes, pressure. The wavelength of the incident light influences strongly the penetration depth of the corresponding evanescent wave. This dependence was exploited here for compensation of the contribution of the bulk refractive index. It was performed using differential SPR measurements at two wavelengths with differing penetration depths. Theoretical analysis and numerical optimization of the suggested approach, named a Penetration Difference Self-Referencing SPR (PDSR-SPR), were performed. Experimental test was performed using 658 and 980 nm laser diodes. Over 20 times suppression of variations of bulk refractive index with magnitude up to 1000 μRIU was observed. Finally, PDSR-SPR approach was applied for monitoring of antibodies binding to the immobilized antigens. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Binaural Rendering in MPEG Surround

    Science.gov (United States)

    Breebaart, Jeroen; Villemoes, Lars; Kjörling, Kristofer

    2008-12-01

    This paper describes novel methods for evoking a multichannel audio experience over stereo headphones. In contrast to the conventional convolution-based approach where, for example, five input channels are filtered using ten head-related transfer functions, the current approach is based on a parametric representation of the multichannel signal, along with either a parametric representation of the head-related transfer functions or a reduced set of head-related transfer functions. An audio scene with multiple virtual sound sources is represented by a mono or a stereo downmix signal of all sound source signals, accompanied by certain statistical (spatial) properties. These statistical properties of the sound sources are either combined with statistical properties of head-related transfer functions to estimate "binaural parameters" that represent the perceptually relevant aspects of the auditory scene or used to create a limited set of combined head-related transfer functions that can be applied directly on the downmix signal. Subsequently, a binaural rendering stage reinstates the statistical properties of the sound sources by applying the estimated binaural parameters or the reduced set of combined head-related transfer functions directly on the downmix. If combined with parametric multichannel audio coders such as MPEG Surround, the proposed methods are advantageous over conventional methods in terms of perceived quality and computational complexity.

  2. Binaural Rendering in MPEG Surround

    Directory of Open Access Journals (Sweden)

    Kristofer Kjörling

    2008-04-01

    Full Text Available This paper describes novel methods for evoking a multichannel audio experience over stereo headphones. In contrast to the conventional convolution-based approach where, for example, five input channels are filtered using ten head-related transfer functions, the current approach is based on a parametric representation of the multichannel signal, along with either a parametric representation of the head-related transfer functions or a reduced set of head-related transfer functions. An audio scene with multiple virtual sound sources is represented by a mono or a stereo downmix signal of all sound source signals, accompanied by certain statistical (spatial properties. These statistical properties of the sound sources are either combined with statistical properties of head-related transfer functions to estimate “binaural parameters” that represent the perceptually relevant aspects of the auditory scene or used to create a limited set of combined head-related transfer functions that can be applied directly on the downmix signal. Subsequently, a binaural rendering stage reinstates the statistical properties of the sound sources by applying the estimated binaural parameters or the reduced set of combined head-related transfer functions directly on the downmix. If combined with parametric multichannel audio coders such as MPEG Surround, the proposed methods are advantageous over conventional methods in terms of perceived quality and computational complexity.

  3. Reduced surround inhibition in musicians.

    Science.gov (United States)

    Shin, Hae-Won; Kang, Suk Y; Hallett, Mark; Sohn, Young H

    2012-06-01

    To investigate whether surround inhibition (SI) in the motor system is altered in professional musicians, we performed a transcranial magnetic stimulation (TMS) study in 10 professional musicians and 15 age-matched healthy non-musicians. TMS was set to be triggered by self-initiated flexion of the index finger at different intervals ranging from 3 to 1,000 ms. Average motor evoked potential (MEP) amplitudes obtained from self-triggered TMS were normalized to average MEPs of the control TMS at rest and expressed as a percentage. Normalized MEP amplitudes of the abductor digiti minimi (ADM) muscles were compared between the musicians and non-musicians with the primary analysis being the intervals between 3 and 80 ms (during the movement). A mixed-design ANOVA revealed a significant difference in normalized ADM MEPs during the index finger flexion between groups, with less SI in the musicians. This study demonstrated that the functional operation of SI is less strong in musicians than non-musicians, perhaps due to practice of movement synergies involving both muscles. Reduced SI, however, could lead susceptible musicians to be prone to develop task-specific dystonia.

  4. All-fiber mode-locked laser via short single-wall carbon nanotubes interacting with evanescent wave in photonic crystal fiber.

    Science.gov (United States)

    Li, Yujia; Gao, Lei; Huang, Wei; Gao, Cong; Liu, Min; Zhu, Tao

    2016-10-03

    We report an all-fiber passively mode-locked laser based on a saturable absorber fabricated by filling short single-wall carbon nanotubes into cladding holes of grapefruit-type photonic crystal fiber. The single-wall carbon nanotube is insensitive to polarization of light for its one-dimensional structure, which suppresses the polarization dependence loss. Carbon nanotubes interact with photonic crystal fiber with ultra-weak evanescent field, which enhances the damage threshold of the saturable absorber and improves the operating stability. In our experiment, conventional soliton with a pulse duration of 1.003 ps and center wavelength of 1566.36 nm under a pump power of 240 mW is generated in a compact erbium-doped fiber laser cavity with net anomalous dispersion of -0.4102 ps2. The signal to noise ratio of the fundamental frequency component is ~80 dB. The maximum average output power of the mode-locked laser reaches 9.56 mW under a pump power of 360 mW. The output power can be further improved by a higher pump power.

  5. Forest Fragments Surrounded by Sugar Cane Are More Inhospitable to Terrestrial Amphibian Abundance Than Fragments Surrounded by Pasture

    Directory of Open Access Journals (Sweden)

    Paula Eveline Ribeiro D’Anunciação

    2013-01-01

    Full Text Available In recent years, there has been increasing interest in matrix-type influence on forest fragments. Terrestrial amphibians are good bioindicators for this kind of research because of low vagility and high philopatry. This study compared richness, abundance, and species composition of terrestrial amphibians through pitfall traps in two sets of semideciduous seasonal forest fragments in southeastern Brazil, according to the predominant surrounding matrix (sugar cane and pasture. There were no differences in richness, but fragments surrounded by sugar cane had the lowest abundance of amphibians, whereas fragments surrounded by pastures had greater abundance. The most abundant species, Rhinella ornata, showed no biometric differences between fragment groups but like many other amphibians sampled showed very low numbers of individuals in fragments dominated by sugar cane fields. Our data indicate that the sugar cane matrix negatively influences the community of amphibians present in fragments surrounded by this type of land use.

  6. Near-field measurement of modal interference in optical nanofibers for sub-Angstrom radius sensitivity

    CERN Document Server

    Fatemi, Fredrik K; Solano, Pablo; Fenton, Eliot F; Beadie, Guy; Rolston, Steven L; Orozco, Luis A

    2016-01-01

    Optical nanofibers (ONF) of subwavelength dimensions confine light in modes with a strong evanescent field that can trap, probe, and manipulate nearby quantum systems. To measure the evanescent field and propagating modes, and to optimize ONF performance, a surface probe is desirable during fabrication. We demonstrate a nondestructive measurement of light propagation in ONFs by sampling the local evanescent field with a microfiber. This approach reveals the behavior of all propagating modes, and because the modal beat lengths in cylindrical waveguides depend strongly on radius, simultaneously provides exquisite sensitivity to the ONF radius. We show that our measured spatial frequencies provide a map of the average ONF radius (over a 600 micrometer window) along the 10 mm ONF waist with 40 picometer resolution and high signal-to-noise ratio. The measurements agree with scanning electron microscopy (SEM) to within SEM instrument resolution. This fast method is immune to polarization, intrinsic birefringence, m...

  7. Functionalization of embedded thiol-ene waveguides for evanescent wave induced fluorescence detection in a microfluidic device

    DEFF Research Database (Denmark)

    Feidenhans'l, Nikolaj Agentoft; Jensen, Thomas Glasdam; Lafleur, Josiane P.

    2013-01-01

    We demonstrate the use of functional surface groups inherently present on off-stoichiometric thiol−ene polymers, for site-specific immobilization of biomolecules and detection by evanescent wave-induced fluorescence. An optofluidic chip featuring an embedded thiol−ene waveguide was selectively...... functionalized with biotin using photografting. The biotin was used for immobilization of fluorescently labelled streptavidin, and experiments revealed a linear correlation between streptavidin concentration and fluorescent intensity. To further demonstrate the attractiveness of using thiol−ene for optofluidic...... devices, the optical properties of thiol−ene was evaluated by determining the transparency and refractive index of the cured polymer....

  8. Functionalization of embedded thiol-ene waveguides for evanescent wave-induced fluorescence detection in a microfluidic device

    DEFF Research Database (Denmark)

    Feidenhans, Nikolaj A.; Jensen, Thomas Glasdam; Lafleur, Josiane P.

    2013-01-01

    We demonstrate the use of functional surface groups inherently present on off-stoichiometric thiol-ene polymers, for site-specific immobilization of biomolecules and detection by evanescent wave-induced fluorescence. An optofluidic chip featuring an embedded thiol-ene waveguide was selectively...... functionalized with biotin using photografting. The biotin was used for immobilization of fluorescently labelled streptavidin, and experiments revealed a linear correlation between streptavidin concentration and fluorescent intensity. To further demonstrate the attractiveness of using thiol-ene for optofluidic...... devices, the optical properties of thiol-ene was evaluated by determining the transparency and refractive index of the cured polymer....

  9. Chemical and isotopic characteristics of rainwater at Los Humeros geothermal field, Puebla, Mexico and surrounding areas; Caracteristicas quimicas e isotopicas del agua de lluvia en el campo geotermico de Los Humeros, Puebla, Mexico y zonas aledanas

    Energy Technology Data Exchange (ETDEWEB)

    Tovar Aguado, Rigoberto; Cruz Grajales, Irma [Comision Federal de Electricidad, Los Humeros, Puebla (Mexico)

    2000-12-01

    A study of chemical and isotopic characteristics of rainwater at Los Humeros geothermal field was undertaken for the second consecutive year. Samples were collected in seven stations-two inside the field and five on the periphery. In 1996, a total of 99 samples were collected and 104 were collected in 1997. Of these, 19-18.26% of the total-had a negative alkalinity. The Atempan (No.5) and Campamento (No.1) stations showed the highest number of anomalous samples (31.25 and 27.8%, respectively). Anomalous samples in Perote station were not observed a result that we attribute to the predominant wind direction. The results for the Campamento station are attributed to the thermal inversion phenomena occurring when the samples with negative alkalinity were obtained. Concentrations of cations in some samples were relatively high, with the maximum concentration of calcium in the Los Humeros station (79.7 ppm) . Other significantly high values were found in the Texcal station (34.8 ppm) and Perote (33.8 ppm) due to the presence of dust particles scattered in the air and because of the lack of pavement where the sampling stations are located. Another factor affecting these figures could be the presence of block and lime factories in the neighborhood. Although measured concentrations may seem high, reports exist with similar concentrations in nongeothermal areas. Oxygen-18 and deuterium contents were determined for each stations, mixing anomalous samples. The results show that the most enriched samples correspond to the San Juan Xiutetelco, Puebla (No. 6) station and the minimum to the Perote Veracruz (No. 7) station. The concentration of SO{sub 4} has marine and industrial origins, with a contribution of the first source ranging between 10 and 25 percent. [Spanish] En el campo geotermico de Los Humeros, Puebla se realizo, por segundo ano consecutivo, la caracterizacion quimica e isotopica de agua de lluvia en muestras colectadas en siete estaciones, dos localizadas dentro

  10. Near-field Moiré effect mediated by surface plasmon polariton excitation.

    Science.gov (United States)

    Liu, Zhaowei; Durant, Stéphane; Lee, Hyesog; Xiong, Yi; Pikus, Yuri; Sun, Cheng; Zhang, Xiang

    2007-03-15

    We have demonstrated a surface plasmon polariton mediated optical Moiré effect by inserting a silver slab between two subwavelength gratings. Enhancement of the evanescent fields by the surface plasmon excitations on the silver slab leads to a remarkable contrast improvement in the Moiré fringes from two subwavelength gratings. Numerical calculations, which agree very well with the experimental observation of evanescent-wave Moiré fringes, elucidate the crucial role of the surface plasmon polaritons. The near-field Moiré effect has potential applications to extend the existing Moiré techniques to subwavelength characterization of nanostructures.

  11. On the use of Indium ({sup 115}In) activation foils for the study of neutron radiation field surrounding a not shielded cyclotron; Sobre o uso de folhas de ativacao de Indio ({sup 115}In) para o estudo do campo de radiacao neutronica ao redor de um ciclotron nao blindado

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Adriana, E-mail: amgr@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Programa de Pos-Graduacao em Ciencia e Tecnologia das Radiacoes, Minerais e Materiais; Rodrigues, Sergio Luiz Moreira; Andrade, Ricardo Severino [Centro de Desenvolvimento da Tecnologia Nuclear (SECPRA/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Pesquisa e Producao de Radiofarmacos; Lacerda, Marco Aurelio de Sousa [Centro de Desenvolvimento da Tecnologia Nuclear (SEPRA/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Protecao Radiologica; Silva, Teogenes Augusto da [Centro de Desenvolvimento da Tecnologia Nuclear (SERAS/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico das Radiacoes Aplicadas a Saude

    2011-10-26

    Use activation foils of {sup 115}In were evaluated for study of neutron radiation field surrounding a non shielded 16.5 MeV cyclotron, during the production of fluorine-18. Two foils of {sup 115}In were used which were exposed to the neutron flux of target-chamber of the GEPETtrace-8 of CDTN/CNEN, Brazil. The first foil were positioned in front of cyclotron beam, and the second one in the diametral opposed position to the beam. It was possible to distinguish for the first foil the 417 keV photo peaks, attributed to the thermal and the 417 keV neutrons attributed to the fast neutrons. On the second foil it was only distinguished the 417 keV photopeak. The results had shown that it is possible to evaluate the fast and thermal neutron fraction surrounding the cyclotron by using indium foils. However, the short half life of the {sup 115}In makes unviable the simultaneous irradiation of a great number of foils

  12. Creating superfluid vortex rings in artificial magnetic fields

    CERN Document Server

    Sachdeva, Rashi

    2016-01-01

    Artificial gauge fields are versatile tools that allow to influence the dynamics of ultracold atoms in Bose-Einstein condensates. Here we discuss a method of artificial gauge field generation stemming from the evanescent fields of the curved surface of an optical nanofibre. The exponential decay of the evanescent fields leads to large gradients in the generalized Rabi frequency and therefore to the presence of geometric vector and scalar potentials. By solving the Gross-Pitaevskii equation in the presence of the artificial gauge fields originating from the fundamental HE$_{11}$ mode of the fibre, we show that vortex rings can be created in a controlled manner. We also calculate the magnetic fields resulting from the higher order HE$_{21}$, TE$_{01}$, and TM$_{01}$ modes and compare them to the fundamental HE$_{11}$ mode.

  13. A study of the flow field surrounding interacting line fires

    Science.gov (United States)

    Trevor Maynard; Marko Princevac; David R. Weise

    2016-01-01

    The interaction of converging fires often leads to significant changes in fire behavior, including increased flame length, angle, and intensity. In this paper, the fluid mechanics of two adjacent line fires are studied both theoretically and experimentally. A simple potential flow model is used to explain the tilting of interacting flames towards each other, which...

  14. Explaining preferences for home surroundings and locations

    Directory of Open Access Journals (Sweden)

    Hans Skifter Andersen

    2011-01-01

    Full Text Available This article is based on a survey carried out in Denmark that asked a random sample of the population about their preferences for home surroundings and locations. It shows that the characteristics of social surroundings are very important and can be divided into three independent dimensions: avoiding social nuisances, preferring social homogeneity and living close to one’s social network and place of origin. The study shows that most people have many detailed preferences, whereas some have very few. This confirms an earlier theory that some people are very connected to certain places with given characteristics and thus do not have priorities regarding home surroundings and locations. For others, mostly young people and singles, home is just a place to sleep and relax, whereas life is lived elsewhere. For this group, there are only preferences for location and there are few specific preferences for surroundings.

  15. Modeling grating contrast discrimination dippers: The role of surround suppression.

    Science.gov (United States)

    To, Michelle P S; Chirimuuta, Mazviita; Tolhurst, David J

    2017-10-01

    We consider the role of nonlinear inhibition in physiologically realistic multineuronal models of V1 to predict the dipper functions from contrast discrimination experiments with sinusoidal gratings of different geometries. The dip in dipper functions has been attributed to an expansive transducer function, which itself is attributed to two nonlinear inhibitory mechanisms: contrast normalization and surround suppression. We ran five contrast discrimination experiments, with targets and masks of different sizes and configurations: small Gabor target/small mask, small target/large mask, large target/large mask, small target/in-phase annular mask, and small target/out-of-phase annular mask. Our V1 modeling shows that the results for small Gabor target/small mask, small target/large mask, large target/large mask configurations are easily explained only if the model includes surround suppression. This is compatible with the finding that an in-phase annular mask generates only little threshold elevation while the out-of-phase mask was more effective. Surrounding mask gratings cannot be equated with surround suppression at the receptive-field level. We examine whether normalization and surround suppression occur simultaneously (parallel model) or sequentially (a better reflection of neurophysiology). The Akaike Criterion Difference showed that the sequential model was better than the parallel, but the difference was small. The large target/large mask dipper experiment was not well fit by our models, and we suggest that this may reflect selective attention for its uniquely larger test stimulus. The best-fit model replicates some behaviors of single V1 neurons, such as the decrease in receptive-field size with increasing contrast.

  16. Portabilidade, evanescências e rubricas: discussões em torno da literatura digital na sala de aula

    Directory of Open Access Journals (Sweden)

    Corrêa, Alamir Aquino

    2016-07-01

    Full Text Available This paper addresses three issues affecting the attempt to teach digital literary texts in the classroom by observing their implications for pedagogical practice in the preparation of future teachers. The integrity of the digital object and its reception, which I call portability, is discussed through the modes of engagement with the text and its unlikely or difficult reproducibility as an aesthetic experience in the classroom. In the case of evanescence, both the access to the aesthetic experience and the study as criticism become problematic due to obstacles like geo-referencing, copyright issues, object transience, and obsolescence of software and hardware. Finally, the guidelines for the reading experience not only organize but also impose a priori limits to the perception of the literary object.

  17. Near field optics and nanoscopy

    CERN Document Server

    Fillard, J P

    1996-01-01

    This book contains the most recent information on optical nanoscopy. Far-Field and Near-Field properties on e.m. waves are presented which illustrate how optical images can be obtained from sub-micron objects. Scanning Probe techniques and computer processing are covered here. An explanation is given on how propagating photons or evanescent waves can behave over distances shorter than the wavelength, taking into account the presence of small objects. Quantum tunneling of photons is explained comparatively with the electron mechanism. Technical details are given on photon tunneling microscopes.

  18. Enhanced sources of acoustic power surrounding AR 11429

    Science.gov (United States)

    Donea, Alina; Hanson, Christopher

    2013-06-01

    Multi-frequency power maps of the local acoustic oscillations show acoustic enhancements ("acoustic-power halos") at high frequencies surrounding large active region. Computational seismic holography reveals a high-frequency "acoustic-emission halo", or "seismic glory" surrounding large active regions. In this study, we have applied computational seismic holography to map the seismic seismic source density surrounding AR 11429. Studies of HMI/SDO Doppler data, shows that the "acoustic halos" and the "seismic glories" are prominent at high frequencies 5-8 mHz. We investigate morphological properties of acoustic-power and acoustic emission halos around an active region to see if they are spatially correlated. Details about the local magnetic field from vectormagnetograms of AR 11429 are included. We identify a 15" region of seismic deficit power (dark moat) shielding the white-light boundary of the active region. The size of the seismic moat is related to region of intermediate magnetic field strength. The acoustic moat is circled by the halo of enhanced seismic amplitude as well as enhanced seismic emission. Overall, the results suggest that features are related. However, if we narrow the frequency band to 5.5 - 6.5 mHz, we find that the seismic source density dominates over the local acoustic power, suggesting the existence of sources that emit more energy downward into the solar interior than upward toward the solar surface.

  19. Tailoring the Electromagnetic Near Field with Patterned Surfaces: Near-Field Plates

    Science.gov (United States)

    2014-12-10

    estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington...plates [9–16] and evanescent field lenses [9], and later as holographic screens [17], metascreens [18] and spatially beam shifted transmission screens...pattern, its spectral representation can be found E⃗focal(ky) = E0 π q0 Π(ky, q◦)x̂, (2) where Π(ky, q0) is the rectangular function with amplitude one

  20. Circuits and Mechanisms for Surround Modulation in Visual Cortex.

    Science.gov (United States)

    Angelucci, Alessandra; Bijanzadeh, Maryam; Nurminen, Lauri; Federer, Frederick; Merlin, Sam; Bressloff, Paul C

    2017-07-25

    Surround modulation (SM) is a fundamental property of sensory neurons in many species and sensory modalities. SM is the ability of stimuli in the surround of a neuron's receptive field (RF) to modulate (typically suppress) the neuron's response to stimuli simultaneously presented inside the RF, a property thought to underlie optimal coding of sensory information and important perceptual functions. Understanding the circuit and mechanisms for SM can reveal fundamental principles of computations in sensory cortices, from mouse to human. Current debate is centered over whether feedforward or intracortical circuits generate SM, and whether this results from increased inhibition or reduced excitation. Here we present a working hypothesis, based on theoretical and experimental evidence, that SM results from feedforward, horizontal, and feedback interactions with local recurrent connections, via synaptic mechanisms involving both increased inhibition and reduced recurrent excitation. In particular, strong and balanced recurrent excitatory and inhibitory circuits play a crucial role in the computation of SM.

  1. Comparative Analysis of Termiteria and Surrounding Soil

    African Journals Online (AJOL)

    Magashi

    2013-06-01

    Jun 1, 2013 ... Variations in the properties of termitaria and their surrounding soil properties within the University of ... and animals. Keywords: AAS, Heavy metals, Makurdi, Soils, Termites. INTRODUCTION. Termites are eusocial insects that live in colonies composed of individuals from ... Also, termite's effects resulted in.

  2. Agroforestry practice in villages surrounding Nyamure former ...

    African Journals Online (AJOL)

    cntaganda

    Abstract. An assessment of fuel wood situation and the contribution of agroforestry and woodlot resources to the supply of household fuel wood requirements were carried out in ten villages surrounding Nyamure former refugee camp, Nyanza District in the Southern. Province. A total of 158 households were surveyed in ...

  3. Agroforestry practice in villages surrounding Nyamure former ...

    African Journals Online (AJOL)

    An assessment of fuel wood situation and the contribution of agroforestry and woodlot resources to the supply of household fuel wood requirements were carried out in ten villages surrounding Nyamure former refugee camp, Nyanza District in the Southern Province. A total of 158 households were surveyed in February ...

  4. Surround-gated vertical nanowire quantum dots

    NARCIS (Netherlands)

    Van Weert, M.H.M.; Den Heijer, M.; Van Kouwen, M.P.; Algra, R.E.; Bakkers, E.P.A.M.; Kouwenhoven, L.P.; Zwiller, V.

    2010-01-01

    We report voltage dependent photoluminescence experiments on single indium arsenide phosphide (InAsP) quantum dots embedded in vertical surround-gated indium phosphide (InP) nanowires. We show that by tuning the gate voltage, we can access different quantum dot charge states. We study the

  5. Religion's relationship with social boundaries surrounding gender ...

    African Journals Online (AJOL)

    This paper examines the religious persuasion on the social boundaries surrounding gender. Gender has been a contentious issue that is associated with segregation, marginalization and differentiation between men and women. In the light of this, scholars' views on the subject matter were considered. Thus, this indicates ...

  6. The discrete dipole approximation with surface interaction for evanescent wave-based characterization of nanostructures on a surface with validation against experimental results

    Science.gov (United States)

    Short, Mitchell R.

    Nanotechnology has become so widely used it can be found in every aspect of life, from cell-phones and computers, to cars, and even athletic socks. As it permeates so many markets, the need for supplemental technologies has also increased. One such needed technology is in the area of nanoscale characterization. Current imaging methods are advanced; however, they do not have the capabilities to characterize the size, shape, composition, and arrangement of nanostructures and nanoparticles in a real-time, unobtrusive manner. The Polarized-Surface-Wave-Scattering system (PSWSS) is a method being researched at the University of Utah that can provide such characterization, although in order for the PSWSS to function accurately through inversion techniques, a predictive forward model must be developed and validated. This work explores the discrete dipole approximation with surface interaction (DDA-SI), an open source MATLAB toolbox, as a predictive model to calculate electromagnetic scattering by objects on a surface illuminated by an evanescent wave generated by total internal reflection (TIR). Far-field scattering predictions via DDA-SI are validated against scaled microwave experimental results for two objects on a surface: a sphere with a diameter of lambda/1.92 and a cube with a side length of lambda/1.785, where lambda refers to the wavelength. A good agreement between experiments and simulations is observed, especially when modified Fresnel reflection coefficients are employed by DDA-SI. Programs to calculate the amplitude scattering matrix and Mueller matrix elements have been also been created. Additionally, the sensitivity of four Mueller matrix elements (M11, M12, M21, and M22) to the particle size, material (gold and silver), shape (sphere and cube), and interparticle spacing, is analyzed. It is found that these four elements are sensitive to changes in shape and interparticle spacing, whereas prove insufficient to difference in material and sizes smaller than

  7. Identification of β-SiC surrounded by relatable surrounding diamond ...

    Indian Academy of Sciences (India)

    Abstract. It is difficult to detect β-SiC using micro-Raman scattering, if it is surrounded by carbon medium. Here, β-SiC is identified in the presence of a relatable surrounding diamond medium using subtle, but discernible Raman surface phonons. In this study, diamond/β-SiC nanocomposite thin film system is considered in ...

  8. Identification of β-SiC surrounded by relatable surrounding diamond ...

    Indian Academy of Sciences (India)

    In this study, diamond/-SiC nanocomposite thin film system is considered in which nanosized -SiC crystallites are surrounded by a relatable nanodiamond medium that leads to the appearance of a weak Raman surface phonon band at about 855 cm-1. Change in the nature of the surrounding material structure and its ...

  9. Multiterminal single-molecule-graphene-nanoribbon junctions with the thermoelectric figure of merit optimized via evanescent mode transport and gate voltage

    DEFF Research Database (Denmark)

    Saha, K.K.; Markussen, Troels; Thygesen, Kristian Sommer

    2011-01-01

    We propose thermoelectric devices where a single molecule is connected to two metallic zigzag graphene nanoribbons (ZGNRs) via highly transparent contacts that allow the injection of evanescent wave functions from ZGNRs. Their overlap generates a peak in the electronic transmission that is largely.......5 at room temperature and 0.5 Green's function formalism for multiterminal devices, we show how the transmission resonance can be manipulated by the voltage applied to a third ZGNR top-gate electrode...

  10. Cholinergic enhancement reduces orientation-specific surround suppression but not visual crowding

    Directory of Open Access Journals (Sweden)

    Anna A. Kosovicheva

    2012-09-01

    Full Text Available Acetylcholine (ACh reduces the spatial spread of excitatory fMRI responses in early visual cortex and the receptive field sizes of V1 neurons. We investigated the perceptual consequences of these physiological effects of ACh with surround suppression and crowding, two tasks that involve spatial interactions between visual field locations. Surround suppression refers to the reduction in perceived stimulus contrast by a high-contrast surround stimulus. For grating stimuli, surround suppression is selective for the relative orientations of the center and surround, suggesting that it results from inhibitory interactions in early visual cortex. Crowding refers to impaired identification of a peripheral stimulus in the presence of flankers and is thought to result from excessive integration of visual features. We increased synaptic ACh levels by administering the cholinesterase inhibitor donepezil to healthy human subjects in a placebo-controlled, double-blind design. In Exp. 1, we measured surround suppression of a central grating using a contrast discrimination task with three conditions: 1 surround grating with the same orientation as the center (parallel, 2 surround orthogonal to the center, or 3 no surround. Contrast discrimination thresholds were higher in the parallel than in the orthogonal condition, demonstrating orientation-specific surround suppression (OSSS. Cholinergic enhancement reduced thresholds only in the parallel condition, thereby reducing OSSS. In Exp. 2, subjects performed a crowding task in which they reported the identity of a peripheral letter flanked by letters on either side. We measured the critical spacing between the target and flanking letters that allowed reliable identification. Cholinergic enhancement had no effect on critical spacing. Our findings suggest that ACh reduces spatial interactions in tasks involving segmentation of visual field locations but that these effects may be limited to early visual cortical

  11. Mechanical characterization of protein L in the low-force regime by electromagnetic tweezers/evanescent nanometry.

    Science.gov (United States)

    Liu, Ruchuan; Garcia-Manyes, Sergi; Sarkar, Atom; Badilla, Carmen L; Fernández, Julio M

    2009-05-06

    Mechanical manipulation at the single molecule level of proteins exhibiting mechanical stability poses a technical challenge that has been almost exclusively approached by atomic force microscopy (AFM) techniques. However, due to mechanical drift limitations, AFM techniques are restricted to experimental recordings that last less than a minute in the high-force regime. Here we demonstrate a novel combination of electromagnetic tweezers and evanescent nanometry that readily captures the forced unfolding trajectories of protein L at pulling forces as low as 10-15 pN. Using this approach, we monitor unfolding and refolding cycles of the same polyprotein for a period of time longer than 30 min. From such long-lasting recordings, we obtain ensemble averages of unfolding step sizes and rates that are consistent with single-molecule AFM data obtained at higher stretching forces. The unfolding kinetics of protein L at low stretching forces confirms and extends the observations that the mechanical unfolding rate is exponentially dependent on the pulling force within a wide range of stretching forces spanning from 13 pN up to 120 pN. Our experiments demonstrate a novel approach for the mechanical manipulation of single proteins for extended periods of time in the low-force regime.

  12. Recurrent focal choroidal excavation following multiple evanescent white dot syndrome (MEWDS) associated with acute idiopathic blind spot enlargement.

    Science.gov (United States)

    Jabbarpoor Bonyadi, Mohammad Hossein; Hassanpour, Kiana; Soheilian, Masoud

    2017-04-03

    To present a recurrent case of conforming focal choroidal excavation (FCE) following multiple evanescent white dot syndrome (MEWDS) in a 25-year-old woman. Following spontaneous MEWDS sings resolution our patient noted a recurrent decrease in vision. Repeated OCT revealed elevation and mild disruption of RPE layer at fovea without previous angiographic MEWDS signs. At this time, short-term systemic steroid therapy was started and visual acuity became normal. Following quiescence of the new-onset phase, the conforming type of FCE located in inferior macula appeared in OCT. In the following next 2 years recurrence of presumptive focal subfoveal choriocapillaritis occurred for three times presenting with blurred vision. During every acute attack, above-mentioned FCE disappeared and returned back again after resolution of presumptive focal choriocapillaritis. This is the first and unique case of recurrent type of FCE following MEWDS. It seems to disappear during active phase of presumptive focal choriocapillaritis and then returns after the eye has become quiescent.

  13. Development of Embedded Fiber-Optic Evanescent Wave Sensors for Optical Characterization of Graphite Anodes in Lithium-Ion Batteries.

    Science.gov (United States)

    Ghannoum, AbdulRahman; Nieva, Patricia; Yu, Aiping; Khajepour, Amir

    2017-11-29

    The development, fabrication, and embedment of fiber-optic evanescent wave sensors (FOEWSs) to monitor the state of charge (SOC) and the state of health (SOH) of lithium-ion batteries (LIBs) are presented. Etching of FOEWSs is performed using a solution of 40 wt % ammonium fluoride (NH4F) and 49 wt % hydrofluoric acid (HF) (6:1), which is found to be superior to an etching solution containing just 49 wt % HF. FOEWSs were characterized using glycerol and found to have the highest sensitivity in a lithium-ion battery when they lose 92% of their transmittance in the presence of glycerol on their sensing region. The physical effect that the FOEWS has on the graphite anode is also investigated and is found to be much more significant in Swagelok cells compared to that in in-house-fabricated pouch cells, mainly due to pressure variation. The FOEWS was found to be most sensitive to the changes in the LIB when it was completely embedded using a slurry of graphite anode material within a pouch cell. The optimized fabrication process of the embedded FOEWS demonstrates the potential of using such sensors commercially for real-time monitoring of the SOC and SOH of LIBs while in operation.

  14. Spirit's Surroundings on 'West Spur,' Sol 305

    Science.gov (United States)

    2005-01-01

    This 360-degree panorama shows the terrain surrounding NASA's Mars Exploration Rover Spirit as of the rover's 305th martian day, or sol, (Nov. 11, 2004). At that point, Spirit was climbing the 'West Spur' of the 'Columbia Hills.' The rover had just finished inspecting a rock called 'Lutefisk' and was heading uphill toward an area called 'Machu Picchu.' Spirit used its navigational camera to take the images combined into this mosaic. The rover's location when the images were taken is catalogued as the mission's site 89, position 205. The view is presented here as a cylindrical projection with geometric seam correction.

  15. Explaining preferences for home surroundings and locations

    DEFF Research Database (Denmark)

    Andersen, Hans Skifter

    2011-01-01

    : avoiding social nuisances, preferring social homogeneity and living close to one’s social network and place of origin. The study shows that most people have many detailed preferences, whereas some have very few. This confirms an earlier theory that some people are very connected to certain places...... with given characteristics and thus do not have priorities regarding home surroundings and locations. For others, mostly young people and singles, home is just a place to sleep and relax, whereas life is lived elsewhere. For this group, there are only preferences for location and there are few specific...

  16. Opportunity's Surroundings on Sol 1818 (Vertical)

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends. This view is presented as a vertical projection with geometric seam correction. North is at the top. The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view. The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

  17. Opportunity's Surroundings on Sol 1818 (Polar)

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends. This view is presented as a polar projection with geometric seam correction. North is at the top. The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view. The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

  18. Towards Semantic Understanding of Surrounding Vehicular Maneuvers

    DEFF Research Database (Denmark)

    Kristoffersen, Miklas Strøm; Dueholm, Jacob Velling; Satzoda, Ravi K.

    2016-01-01

    This paper proposes the use of multiple low-cost visual sensors to obtain a surround view of the ego-vehicle for semantic understanding. A multi-perspective view will assist the analysis of naturalistic driving studies (NDS), by automating the task of data reduction of the observed sequences...... is tested on ten sequences of real-world data collected on U. S. highways. The results show the potential use of multiple low-cost visual sensors for semantic understanding around the ego-vehicle....

  19. Near-field observation of spatial phase shifts associated with Goos-Hänschen and surface plasmon resonance effects

    NARCIS (Netherlands)

    Jose, J.; Segerink, Franciscus B.; Korterik, Jeroen P.; Offerhaus, Herman L.

    2008-01-01

    We report the near-field observation of the phase shifts associated with total internal reflection on a glass-air interface and surface plasmon resonance on a glass-gold-air system. The phase of the evanescent waves on glass and gold surfaces, as a function of incident angle, is measured using a

  20. Manipulation and detection of atoms using plasmon-enhanced evanescent waves over dielectric waveguides

    Science.gov (United States)

    Yik, Johnathan

    Atom chip devices confine atoms by using the superposition of magnetic fields due to a current along with a uniform external field, generating a linear magnetic potential well along the line of the current. These devices are used in atomic physics experiments due to their ability to produce extremely tight confinements. In particular, the high phase-space densities made available by tight confinements allow rapid creation of Bose-Einstein condensates, while the strength of the transverse confinement compared to the weak axial confinement allows 1-dimensional states of matter to be created and studied. To achieve such tight confinements, atoms must be trapped very close to the chip surface. However, detection of atoms is difficult at small separations from the surface. Additionally, irregularities in the current-carrying wires produce corrugations in the trapping potential, causing fragmentation of trapped atoms, as well as undesired excitations out of the ground state. In this thesis, the integration of optical waveguides on the surface of atom chips is proposed, in order to address the previously-mentioned problems with atom confinement near the chip surface. (Abstract shortened by UMI.).

  1. Opportunity's Surroundings After Sol 1820 Drive (Polar)

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009). This view is presented as a polar projection with geometric seam correction. North is at the top. The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock.

  2. Opportunity's Surroundings on Sol 1798 (Vertical)

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top. This view is presented as a vertical projection with geometric seam correction. The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

  3. Opportunity's Surroundings on Sol 1798 (Polar)

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top. This view is presented as a polar projection with geometric seam correction. The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

  4. Opportunity's Surroundings After Sol 1820 Drive

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009). South is at the center; north at both ends. The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock. This view is presented as a cylindrical projection with geometric seam correction.

  5. Surround inhibition of mammalian AII amacrine cells is generated in the proximal retina.

    Science.gov (United States)

    Bloomfield, S A; Xin, D

    2000-03-15

    1. Intracellular recordings were obtained from neurons in the superfused retina-eyecup preparation of the rabbit under dark-adapted conditions. Neurotransmitter agonists and antagonists were applied exogenously via the superfusate to dissect the synaptic pathways pharmacologically and thereby determine those pathways responsible for the generation of the on-centre/off-surround receptive fields of AII amacrine cells. 2. Application of the metabotropic glutamate receptor agonist, APB, reversibly blocked both the on-centre and off-surround responses of AII cells. These data were consistent with the idea that both the centre- and surround-mediated responses are derived from inputs from the presynaptic rod bipolar cells. 3. Whereas rod bipolar cells showed on-receptive fields approximately 100 microm across, we found no evidence for an antagonistic off-surround response using light stimuli which effectively elicited the off-surrounds of AII amacrine cells. These results indicated that the surrounds of AII cells are not derived from rod bipolar cell inputs. 4. Application of the ionotropic glutamate receptor antagonists CNQX or DNQX enhanced the on-centre responses of AII cells but attenuated the off-surround responses. These data indicated that the centre- and surround-mediated responses could not both be derived from signals crossing the rod bipolar-to-AII cell synapse. 5. Application of the glycine antagonist, strychnine, had only minor and variable effects on AII cell responses. However, the GABA antagonists picrotoxin and bicuculline enhanced the on-centre response but attenuated or completely blocked the off-surround response of AII cells. The GABA antagonists had no effect on the responses of horizontal cells indicating that their effects on AII cell responses reflected actions on inner retinal circuitry rather than feedback circuitry in the outer plexiform layer. 6. Application of the voltage-gated sodium channel blocker TTX enhanced the on-centre responses of

  6. Global structure of static spherically symmetric solutions surrounded by quintessence

    Science.gov (United States)

    Cruz, Miguel; Ganguly, Apratim; Gannouji, Radouane; Leon, Genly; Saridakis, Emmanuel N.

    2017-06-01

    We investigate all static spherically symmetric solutions in the context of general relativity surrounded by a minimally-coupled quintessence field, using dynamical system analysis. Applying the 1  +  1  +  2 formalism and introducing suitable normalized variables involving the Gaussian curvature, we were able to reformulate the field equations as first order differential equations. In the case of a massless canonical scalar field we recovered all known black hole results, such as the Fisher solution, and we found that apart from the Schwarzschild solution all other solutions are naked singularities. Additionally, we identified the symmetric phase space which corresponds to the white hole part of the solution and in the case of a phantom field, we were able to extract the conditions for the existence of wormholes and define all possible classes of solutions such as cold black holes, singular spacetimes and wormholes such as the Ellis wormhole, for example. For an exponential potential, we found that the black hole solution which is asymptotically flat is unique and it is the Schwarzschild spacetime, while all other solutions are naked singularities. Furthermore, we found solutions connecting to a white hole through a maximum radius, and not a minimum radius (throat) such as wormhole solutions, therefore violating the flare-out condition. Finally, we have found a necessary and sufficient condition on the form of the potential to have an asymptotically AdS spacetime along with a necessary condition for the existence of asymptotically flat black holes.

  7. Opportunity's Surroundings on Sol 1798 (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11850 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11850 NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  8. The lithosphere-asthenosphere Italy and surroundings

    CERN Document Server

    Panza, G F; Chimera, G; Pontevivo, A; Raykova, R

    2003-01-01

    The velocity-depth distribution of the lithosphere-asthenosphere in the Italian region and surroundings is imaged, with a lateral resolution of about 100 km, by surface wave velocity tomography and non-linear inversion. Maps of the Moho depth, of the thickness of the lithosphere and of the shear-wave velocities, down to depths of 200 km and more, are constructed. A mantle wedge, identified in the uppermost mantle along the Apennines and the Calabrian Arc, underlies the principal recent volcanoes, and partial melting can be relevant in this part of the uppermost mantle. In Calabria a lithospheric doubling is seen, in connection with the subduction of the Ionian lithosphere. The asthenosphere is shallow in the Southern Tyrrhenian Sea. High velocity bodies, cutting the asthenosphere, outline the Adria-lonian subduction in the Tyrrhenian Sea and the deep-reaching lithospheric root in the Western Alps. Less deep lithospheric roots are seen in the Central Apennines. The lithosphere-asthenosphere properties delineat...

  9. Opportunity's Surroundings After Sol 1820 Drive (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11841 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11841 NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009). This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  10. Opportunity's Surroundings on Sol 1818 (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11846 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11846 NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view. The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  11. Ozone bioindication in Barcelona and surrounding area of Catalonia

    Energy Technology Data Exchange (ETDEWEB)

    Ribas, A.; Penuelas, J. [Univ. Autonoma de Barcelona, Barcelona (Spain). Ecophysiology Unit of CSIC

    2002-07-01

    A field study was conducted from July to September 2000 to assess ozone (O{sub 3}) phytotoxicity in Barcelona and surrounding areas of Catalonia (NE Spain) by using tobacco plants Bel-W3 and Populus nigra 'Brandaris' as bioindicators. The study was conducted simultaneously at eight sites where ozone concentrations and meteorological variables were continuously monitored. The ozone levels correlated well with ozone injury on the Bel-W3 cultivar, especially at stations established in the urban area of Barcelona, and in the first months of summer. In the second half of summer plants showed a decreasing efficiency in its biomonitoring capacity. The behaviour of Populus as bioindicator or biomonitor was less satisfactory. For both species it is necessary to improve cultivation conditions since water deficits seem to play an important role in bioindication in the Mediterranean region. (orig.)

  12. Synthesis of Passive Lossless Metasurfaces Using Auxiliary Fields for Reflectionless Beam Splitting and Perfect Reflection.

    Science.gov (United States)

    Epstein, Ariel; Eleftheriades, George V

    2016-12-16

    We introduce a paradigm for accurate design of metasurfaces for intricate beam manipulation, implementing functionalities previously considered impossible to achieve with passive lossless elements. The key concept involves self-generation of auxiliary evanescent fields which facilitate the required local power conservation, without interfering with the device performance in the far field. We demonstrate our scheme by presenting exact reactive solutions to the challenging problems of reflectionless beam splitting and perfect reflection, verified via full wave simulations.

  13. Dead discs, unstable discs and the stars they surround

    Directory of Open Access Journals (Sweden)

    D’Angelo Caroline

    2014-01-01

    Full Text Available Strong stellar magnetic fields significantly alter the behaviour of surrounding accretion discs. Recent work has demonstrated that at low accretion rates a large amount of mass can remain confined in the disc, contrary to the standard assumption that the magnetic field will expel the disc in an outflow (the “propeller regime”. These “dead discs” often become unstable, causing cycles of accretion onto the central star. Here I present the main predictions of this model, and argue that it provides a good explanation for the peculiar behaviour seen in several accreting sources with strong magnetic fields. I will focus in particular on three accreting millisecond X-ray pulsars: SAX J1808.4-3658, NGC 6440 X-2 and IGR J00291+5934. These sources all show low-frequency quasi-periodic oscillations consistent with a variable accretion rate, as well as unusual outburst patterns that suggest gas is confined in the inner disc regions during quiescence.

  14. Experimental studies of far-field superlens for sub-diffractional optical imaging.

    Science.gov (United States)

    Liu, Zhaowei; Durant, Stéphane; Lee, Hyesog; Pikus, Yuri; Xiong, Yi; Sun, Cheng; Zhang, Xiang

    2007-05-28

    Contrary to the conventional near-field superlensing, subwavelength superlens imaging is experimentally demonstrated in the far-field. The key element is termed as a Far-field SuperLens (FSL) which consists of a conventional superlens and a nanoscale coupler. The evanescent fields from the object are enhanced and then converted into propagating fields by the FSL. By only measuring the propagating field in the far-field, the object image can be reconstructed with subwavelength resolution. As an example of this concept, we design and fabricate a silver structured one dimensional FSL. Experimental results show that feature resolution of better than 50nm is possible using current FSL design.

  15. Invariant superoscillatory electromagnetic fields in 3D-space

    Science.gov (United States)

    Makris, K. G.; Papazoglou, D. G.; Tzortzakis, S.

    2017-01-01

    We derive exact solutions of Maxwell’s equations based on superoscillatory superpositions of vectorial Bessel beams. These novel beams are diffraction-free and can support subwavelength features in their transverse electromagnetic fields, without the presence of any evanescent waves. These features can be propagated into the far field. Approximate solutions in closed form are also derived based on asymptotic expansions of Bessel functions for simple prescribed subwavelength patterns. The superoscillatory characteristics of both electric, magnetic field components (transverse and longitudinal), and the Poynting vector, as well as, the effect of nonparaxiality are systematically investigated.

  16. Near-Field Optical Microscopy of Fractal Structures

    DEFF Research Database (Denmark)

    Coello, Victor; Bozhevolnyi, Sergey I.

    1999-01-01

    Using a photon scanning tunnelling microscope combined with a shear-force feedback system, we image both topographical and near-field optical images (at the wavelengths of 633 and 594 nm) of silver colloid fractals. Near-field optical imaging is calibrated with a standing evanescent wave pattern....... Near-field optical images exhibit spatially localized (within 150-250 nm) intensity enhancement (by up to 20 times) in the form of round bright spots, whose positions and brightness are found to be sensitive to the light wavelength, polarization and angle of incidence. The observed phenomenon...

  17. Transmission and Distribution of Optical Field in Prism Coupler

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C Q; Chen, M [College of Physics and Electronics Information, Hunan Institute of Science and Technology, Yueyang 414006 (China); Liu, J; Wan, Z M; Luo, Z M [College of Information and Communication Engineering, Hunan Institute of Science and Technology, Yueyang 414006 (China); Tian, P, E-mail: namecqh@yahoo.com.cn [College of Optoelectronic Science and Engineering, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074 (China)

    2011-02-01

    Transmission and distribution characteristics of optical field in prism coupler are studies, and the phase matching function of prism coupler is deduced based on coupled wave theory. It is shown that the stable light field distribution and mode pattern are determined by its own geometric and dielectric parameters, but have nothing to do with the categories of incident light sources. It is also found that the coupling effect would generate between waveguides through evanescent field. Our numerical simulation is based on the finite difference time domain method with perfectly matched layer absorbing boundary condition. The simulation program is compiled in MATLAB. The simulation results are analyzed carefully.

  18. Convection surrounding mesoscale ionospheric flow channels

    Science.gov (United States)

    Rinne, Y.; Moen, J.; Baker, J. B. H.; Carlson, H. C.

    2011-05-01

    We evaluate data from the European Incoherent Scatter (EISCAT) Svalbard radar (ESR) and Defense Meteorological Satellite Program (DMSP) spacecraft coupled with data from the Super Dual Auroral Radar Network (SuperDARN) polar cap convection patterns in order to study how the ionospheric convection evolves around a sequence of transient, mesoscale flow channel events in the duskside of the cusp inflow region. On a northwestward convection background for the interplanetary magnetic field (IMF) BY positive and BZ negative, a sequence of three eastward flow channels formed over the course of 1 hour in response to three sharp IMF rotations to IMF BY negative and IMF BZ positive. The first and third channels, due to IMF BY negative periods of ˜13 min and >30 min, respectively, develop in a similar manner: they span the entire ESR field of view and widen poleward with increasing time elapsed since their first appearance until the IMF rotates back. The convection patterns are consistent with the line-of-sight data from the ESR and DMSP within a 10 min adaption time. The flow lines form a twin-vortex flow, with the observed channel being the twin vortices' center flow. The fitting algorithm was pushed to its limits in terms of spatial resolution in this study. During portions of the channel events, the suggested twin-cell flow is not in agreement with our physical interpretation of the flow channels being reconnection events because cell closure is suggested across an anticipated nonreconnecting open-closed boundary. For these segments, we present simulated patterns which have been arrived at by a combination of looking at the raw data and examining the fitted convection patterns.

  19. Temporal properties of centre-surround interactions in human motion perception

    NARCIS (Netherlands)

    Perge, J.A.; Kanai, R.; Wezel, R.J.A. van; Lankheet, M.J.M.

    2003-01-01

    A recent electrophysiological study revealed that the response to the antagonistic surround of macaque area MT receptive fields is delayed (15 - 20 ms) relative to the centre (Perge et al, 2002 Investigative Ophthalmology & Visual Science 43 E-Abstract 3931). We investigated whether this phenomenon,

  20. P1-13: Color Induction from Surround Color under Interocular Suppression

    Directory of Open Access Journals (Sweden)

    Ichiro Kuriki

    2012-10-01

    Full Text Available The effect of surround colors on color appearance is known to subserve color constancy in humans, but how multiple mechanisms in the visual system are involved in this effect is controversial. We used an interocular-suppression technique to examine how the effect occurs at the level higher than the interaction of binocular information. A test color chip (1.7 × 1.7 deg visual angle was presented in a static surround either with continuous-flash suppression in the dominant eye (CFS condition to make the surround inperceptible or without the suppression (no-CFS condition. The surround stimulus was either a Mondrian or a uniform field of the same mean chromaticity. Stimuli were simulated OSA color chips under red, white (D65, or green illuminant color and were presented on a CRT display. Unique yellows were measured by asking the subjects to judge whether the test stimulus appeared reddish or greenish. Two sizes of the surround stimuli (widths of 1 deg and 4 deg were used. Results showed significant shifts in unique yellow even under the CFS conditions, except for the 1 deg uniform-surround condition. Under the no-CFS condition, the shifts showed remarkable difference between subjects, except for the 4 deg Mondrian-surround condition. Interestingly, trends of the shifts showed high consistency within each subject, across conditions. These results indicate that mechanisms at both higher and lower levels than the neuronal site of interocular suppression are involved, and that the color shifts follow each subject's strategy in the higher-order mechanisms when only insufficient clues are available in the surround to estimate illuminant color.

  1. Multi-step surface functionalization of polyimide based evanescent wave photonic biosensors and application for DNA hybridization by Mach-Zehnder interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Melnik, Eva [Health and Environment Department, Nano Systems, AIT Austrian Institute of Technology GmbH, Donau-City-Strasse 1, 1220 Vienna (Austria); Department of Analytical Chemistry, University of Vienna, Waehringer Strasse 38, 1090 Vienna (Austria); Bruck, Roman [Health and Environment Department, Nano Systems, AIT Austrian Institute of Technology GmbH, Donau-City-Strasse 1, 1220 Vienna (Austria); Hainberger, Rainer, E-mail: rainer.hainberger@ait.ac.at [Health and Environment Department, Nano Systems, AIT Austrian Institute of Technology GmbH, Donau-City-Strasse 1, 1220 Vienna (Austria); Laemmerhofer, Michael, E-mail: michael.laemmerhofer@univie.ac.at [Department of Analytical Chemistry, University of Vienna, Waehringer Strasse 38, 1090 Vienna (Austria)

    2011-08-12

    Highlights: {yields} We realize a biosensing platform for polyimide evanescent photonic wave sensors. {yields} We show that the surface functionalization via silanisation and biotinylation followed by streptavidin immobilization do not destroy or damage the thin polyimide film. {yields} A highly dense streptavidin layer enables the immobilisation of biotinylated ligands such as biotinylated ssDNA for the selective measurement of DNA hybridization. - Abstract: The process of surface functionalization involving silanization, biotinylation and streptavidin bonding as platform for biospecific ligand immobilization was optimized for thin film polyimide spin-coated silicon wafers, of which the polyimide film serves as a wave guiding layer in evanescent wave photonic biosensors. This type of optical sensors make great demands on the materials involved as well as on the layer properties, such as the optical quality, the layer thickness and the surface roughness. In this work we realized the binding of a 3-mercaptopropyl trimethoxysilane on an oxygen plasma activated polyimide surface followed by subsequent derivatization of the reactive thiol groups with maleimide-PEG{sub 2}-biotin and immobilization of streptavidin. The progress of the functionalization was monitored by using different fluorescence labels for optimization of the chemical derivatization steps. Further, X-ray photoelectron spectroscopy and atomic force microscopy were utilized for the characterization of the modified surface. These established analytical methods allowed to derive information like chemical composition of the surface, surface coverage with immobilized streptavidin, as well as parameters of the surface roughness. The proposed functionalization protocol furnished a surface density of 144 fmol mm{sup -2} streptavidin with good reproducibility (13.9% RSD, n = 10) and without inflicted damage to the surface. This surface modification was applied to polyimide based Mach-Zehnder interferometer

  2. Energy modulation of nonrelativistic electrons in an optical near field on a metal microslit

    Science.gov (United States)

    Ishikawa, R.; Bae, J.; Mizuno, K.

    2001-04-01

    Energy modulation of nonrelativistic electrons with a laser beam using a metal microslit as an interaction circuit has been investigated. An optical near field is induced in the proximity of the microslit by illumination of the laser beam. The electrons passing close to the slit are accelerated or decelerated by an evanescent wave contained in the near field whose phase velocity is equal to the velocity of the electrons. The electron-evanescent wave interaction in the microslit has been analyzed theoretically and experimentally. The theory has predicted that electron energy can be modulated at optical frequencies. Experiments performed in the infrared region have verified theoretical predictions. The electron-energy changes of more than ±5 eV with a 10 kW CO2 laser pulse at the wavelength of 10.6 μm has been successfully observed for an electron beam with an energy of less than 80 keV.

  3. Enhanced sources of acoustic power surrounding AR11429

    OpenAIRE

    Donea, Alina; Hanson, Christopher

    2013-01-01

    Multi-frequency power maps of the local acoustic oscillations show acoustic enhancements (\\acoustic-power halos") at high frequencies surrounding large active region. Computational seismic holography reveals a high-frequency \\acoustic-emission halo", or \\seismic glory" surrounding large active regions. In this study, we have applied computational seismic holography to map the seismic seismic source density surrounding AR 11429. Studies of HMI/SDO Doppler data, shows that the "acoustic halos" ...

  4. Teacher Leadership: Everyday Practices Surrounding Work- Related Stress

    National Research Council Canada - National Science Library

    Chiweshe Nigel

    2015-01-01

    This interpretivist study contributes to our scholarly understanding of how everyday practices surrounding work-related stress in education affect teacher leadership and successful learning outcomes...

  5. How A Black Hole Lights Up Its Surroundings

    Science.gov (United States)

    Kohler, Susanna

    2017-10-01

    How do the supermassive black holes that live at the centers of galaxies influence their environments? New observations of a distant active galaxy offer clues about this interaction.Signs of CoevolutionPlot demonstrating the m-sigma relation, the empirical correlation between the stellar velocity dispersion of a galactic bulge and the mass of the supermassive black hole at its center. [Msigma]We know that the centers of active galaxies host supermassive black holes with masses of millions to billions of suns. One mystery surrounding these beasts is that they are observed to evolve simultaneously with their host galaxies for instance, an empirical relationship is seen between the growth of a black hole and the growth of its host galaxys bulge. This suggests that there must be a feedback mechanism through which the evolution of a black hole is linked to that of its host galaxy.One proposed source of this coupling is the powerful jets emitted from the poles of these supermassive black holes. These jets are thought to be produced as some of the material accreting onto the black hole is flung out, confined by surrounding gas and magnetic fields. Because the jets of hot gas and radiation extend outward through the host galaxy, they provide a means for the black hole to influence the gas and dust of its surroundings.In our current model of a radio-loud active galactic nuclei,a region of hot, ionized gas the narrow-line region lies beyond the sphere of influence of the supermassive black hole. [C.M. Urry and P. Padovani]Clues in the Narrow-Line RegionThe region of gas thought to sit just outside of the black holes sphere of influence (at a distance of perhaps a thousand to a few thousand light-years) is known as the narrow line region so named because we observe narrow emission lines from this gas. Given its hot, ionized state, this gas must somehow be being pummeled with energy. In the canonical picture, radiation from the black hole heats the gas directly in a process

  6. A nebula of gases from Io surrounding Jupiter.

    Science.gov (United States)

    Krimigis, Stamatios M; Mitchell, Donald G; Hamilton, Douglas C; Dandouras, Jannis; Armstrong, Thomas P; Bolton, Scott J; Cheng, Andrew F; Gloeckler, George; Hsieh, K C; Keath, Edwin P; Krupp, Norbert; Lagg, Andreas; Lanzerotti, Louis J; Livi, Stefano; Mauk, Barry H; McEntire, Richard W; Roelof, Edmond C; Wilken, Berend; Williams, Donald J

    2002-02-28

    Several planetary missions have reported the presence of substantial numbers of energetic ions and electrons surrounding Jupiter; relativistic electrons are observable up to several astronomical units (au) from the planet. A population of energetic (>30[?]keV) neutral particles also has been reported, but the instrumentation was not able to determine the mass or charge state of the particles, which were subsequently labelled energetic neutral atoms. Although images showing the presence of the trace element sodium were obtained, the source and identity of the neutral atoms---and their overall significance relative to the loss of charged particles from Jupiter's magnetosphere---were unknown. Here we report the discovery by the Cassini spacecraft of a fast (>103[?]km[?]s-1) and hot magnetospheric neutral wind extending more than 0.5[?]au from Jupiter, and the presence of energetic neutral atoms (both hot and cold) that have been accelerated by the electric field in the solar wind. We suggest that these atoms originate in volcanic gases from Io, undergo significant evolution through various electromagnetic interactions, escape Jupiter's magnetosphere and then populate the environment around the planet. Thus a 'nebula' is created that extends outwards over hundreds of jovian radii.

  7. Saturated evanescent-wave absorption of few-layer graphene-covered side-polished single-mode fiber for all-optical switching

    Science.gov (United States)

    Peng, Kaung-Jay; Wu, Chun-Lung; Lin, Yung-Hsiang; Wang, Hwai-Yung; Cheng, Chih-Hsien; Chi, Yu-Chieh; Lin, Gong-Ru

    2018-01-01

    Using the evanescent-wave saturation effect of hydrogen-free low-temperature synthesized few-layer graphene covered on the cladding region of a side-polished single-mode fiber, a blue pump/infrared probe-based all-optical switch is demonstrated with specific wavelength-dependent probe modulation efficiency. Under the illumination of a blue laser diode at 405 nm, the few-layer graphene exhibits cross-gain modulation at different wavelengths covering the C- and L-bands. At a probe power of 0.5 mW, the L-band switching throughput power variant of 16 μW results in a probe modulation depth of 3.2%. Blue shifting the probe wavelength from 1580 to 1520 nm further enlarges the switching throughput power variant to 24 mW and enhances the probe modulation depth to 5%. Enlarging the probe power from 0.5 to 1 mW further enlarges the switching throughput power variant from 25 to 58 μW to promote its probe modulation depth of up to 5.8% at 1520 nm. In contrast, the probe modulation depth degrades from 5.1% to 1.2% as the pumping power reduces from 85 to 24 mW, which is attributed to the saturable absorption of the few-layer graphene-based evanescent-wave absorber. The modulation depth at wavelength of 1550 nm under a probe power of 1 mW increases from 1.2% to 5.1%, as more carriers can be excited when increasing the blue laser power from 24 to 85 mW, whereas it decreases from 5.1% to 3.3% by increasing the input probe power from 1 to 2 mW to show an easier saturated condition at longer wavelength.

  8. Comparative Analysis of Termiteria and Surrounding Soil Properties ...

    African Journals Online (AJOL)

    Comparative Analysis of Termiteria and Surrounding Soil Properties in the University of Agriculture, Makurdi, Nigeria. IS Eneji, R Sha'Ato, SE Ejembi. Abstract. Variations in the properties of termitaria and their surrounding soil properties within the University of Agriculture Makurdi were investigated using routine soil analysis ...

  9. The bird species of pandam wildlife park and the surrounding ...

    African Journals Online (AJOL)

    This study investigated the bird species abundance and diversity of the Pandam wildlife park and the surrounding farmlands. The effect of time of day as well as vegetation variables on bird species diversity in the park and surrounding farmlands was also conducted. 10 transects in each study site were surveyed twice ...

  10. HIV behavioural surveillance among refugees and surrounding host ...

    African Journals Online (AJOL)

    We used a standardised behavioural surveillance survey (BSS), modified to be directly relevant to populations in conflict and post-conflict settings as well as to their surrounding host populations, to survey the populations of a refugee settlement in south-western Uganda and its surrounding area. Two-stage probability ...

  11. Nanofocusing performance of the crescent-shaped cylinder for various surrounding media

    Directory of Open Access Journals (Sweden)

    Hong-Wei Wu

    2014-11-01

    Full Text Available In this work, adjustable broadband light harvesting and field enhancement on the surface of a crescent-shaped cylinder were achieved by considering the surrounding medium in conformal transformation theory. The continuous absorption spectrum shows that the broadband effect is quite robust to the surrounding media. By considering the material properties, we provide a comprehensive discussion of how the material properties of the nanosystem affect the field enhancement and nanofocusing. Furthermore, an optical gain medium is employed to compensate for the absorption losses in the materials. A considerable field enhancement and super-nanofocusing are thus expected. The presented results provide important guidance for optimizing such a nanosystem in experimental studies.

  12. Research of strain distribution and strain rate change in the fracture surroundings by the videoextensometric methode

    Directory of Open Access Journals (Sweden)

    M. Mihaliková

    2010-07-01

    Full Text Available The paper deals with the strain distribution and the strain rate of material in the surroundings of its fracture. Three steels applied in the automotive industry (DP - dual phase steel, microalloyed steel HR 45 and IF - interstitial free steel were used as the experimental material. The videoextensometric technique was used for sensing with CCD camera and computer. During the test, software records the coordinates of the centres of gravity of individual points, from which the respective strain values are then obtained. For individual steel grades, strain field maps in the fracture surroundings were plotted. The change in the strain rate in the fracture surroundings and at places more distant from the fracture was observed.

  13. Spatial sensitivity, responsivity, and surround suppression of LGN cell responses in the macaque.

    Science.gov (United States)

    Seim, Thorstein; Valberg, Arne

    2013-07-01

    Responses of cells in the lateral geniculate nucleus (LGN) of the macaque monkey have been measured for different sizes of chromatic and achromatic stimuli, with relative luminance spanning a range of 3-6 log units. Homogeneous illuminated test fields, centered on the receptive field, were used. Responses to these stimuli deviated from what is expected for the grating stimuli used to study the contrast-sensitive mechanisms in the visual pathway. For test fields smaller than the center of the receptive field, both the excitatory and the inhibitory cone-opponent components were present in the response, and the sensitivity to both components increased with the same factor when the test field increased in size (area summation). For test field areas extending into the suppressive surround of the extraclassical receptive field, the excitatory and the inhibitory cone opponents were both suppressed, again by the same factor. This suppression of the cell's responsiveness, as a function of test spot area, was described by a logarithmic function, and the spatial sensitivity of attenuation could therefore be described by a power function of radius. The logarithmic suppression was clear for parvocellular and koniocellular cells but was more prominent for magnocellular cells. The surround field suppression was also found for the prepotential inputs to LGN cells, indicating a retinal origin. The difference of Gaussian (DOG) model has been used successfully to describe the cells' contrast behavior for grating stimuli. However, this model fails to describe the constant excitatory/inhibitory response balance needed to obtain color (hue) stability for light stimuli of different sizes but with the same Commission Internationale de l'Eclairage (CIE) chromaticity and luminance factor. Neither the constant responsiveness found in the center of the receptive field nor the suppressive response in the surround can be described by the DOG model.

  14. On the transition to the normal phase for superconductors surrounded by normal conductors

    DEFF Research Database (Denmark)

    Fournais, Søren; Kachmar, Ayman

    2009-01-01

    critical fields coincide. In particular, when the conductivity ratio of the superconducting and the normal material is large, we show that the aforementioned critical magnetic fields coincide, thereby proving that the transition to the normal phase is sharp. One key-ingredient in the paper is the analysis......For a cylindrical superconductor surrounded by a normal material, we discuss transition to the normal phase of stable, locally stable and critical configurations. Associated with those phase transitions, we define critical magnetic fields and we provide a sufficient condition for which those...

  15. Rain Simulation for the Test of Automotive Surround Sensors

    Science.gov (United States)

    Hasirlioglu, Sinan; Riener, Andreas; Doric, Igor

    2017-04-01

    The WHO Global Health Observatory data indicates that over 1.25 million people die in traffic accidents annually. To save lives, car manufacturers spend lot of efforts on the development of novel safety systems aiming to avoid or mitigate accidents and provide maximum protection for vehicle occupants as well as vulnerable road users. All the safety features mainly rely on data from surround sensors such as radar, lidar and camera and intelligent vehicles today use these environmental data for instant decision making and vehicle control. As already small errors in sensor data measurements could lead to catastrophes like major injuries or road traffic fatalities, it is of utmost importance to ensure high reliability and accuracy of sensors and safety systems. This work focuses on the influence of environmental factors such as rain conditions, as it is known that rain drops scatter the electromagnetic waves. The result is incorrect measurements with a direct negative impact on environment detection. To identify potential problems of sensors under varying environmental conditions, systems are today tested in real-world settings with two main problems: First, tests are time-consuming and second, environmental conditions are not reproducible. Our approach to test the influence of weather on automotive sensors is to use an indoor rain simulator. Our artificial rain maker, installed at CARISSMA (Center of Automotive Research on Integrated Safety Systems and Measurement Area), is parametrized with rain characteristics measured in the field using a standard disdrometer. System behavior on artificial rain is compared and validated with natural rainfall. With this simulator it is finally possible to test environmental influence at various levels and under reproducible conditions. This saves lot of efforts required for the test process itself and furthermore has a positive impact on the reliability of sensor systems due to the fact that test driven development is enabled.

  16. Surrounding Moving Obstacle Detection for Autonomous Driving Using Stereo Vision

    Directory of Open Access Journals (Sweden)

    Hao Sun

    2013-06-01

    Full Text Available Detection and tracking surrounding moving obstacles such as vehicles and pedestrians are crucial for the safety of mobile robotics and autonomous vehicles. This is especially the case in urban driving scenarios. This paper presents a novel framework for surrounding moving obstacles detection using binocular stereo vision. The contributions of our work are threefold. Firstly, a multiview feature matching scheme is presented for simultaneous stereo correspondence and motion correspondence searching. Secondly, the multiview geometry constraint derived from the relative camera positions in pairs of consecutive stereo views is exploited for surrounding moving obstacles detection. Thirdly, an adaptive particle filter is proposed for tracking of multiple moving obstacles in surrounding areas. Experimental results from real-world driving sequences demonstrate the effectiveness and robustness of the proposed framework.

  17. Camouflaging in a complex environment--octopuses use specific features of their surroundings for background matching.

    Directory of Open Access Journals (Sweden)

    Noam Josef

    Full Text Available Living under intense predation pressure, octopuses evolved an effective and impressive camouflaging ability that exploits features of their surroundings to enable them to "blend in." To achieve such background matching, an animal may use general resemblance and reproduce characteristics of its entire surroundings, or it may imitate a specific object in its immediate environment. Using image analysis algorithms, we examined correlations between octopuses and their backgrounds. Field experiments show that when camouflaging, Octopus cyanea and O. vulgaris base their body patterns on selected features of nearby objects rather than attempting to match a large field of view. Such an approach enables the octopus to camouflage in partly occluded environments and to solve the problem of differences in appearance as a function of the viewing inclination of the observer.

  18. All-fiber Tm-doped soliton laser oscillator with 6 nJ pulse energy based on evanescent field interaction with monoloayer graphene saturable absorber.

    Science.gov (United States)

    Jeong, Hwanseong; Choi, Sun Young; Kim, Mi Hye; Rotermund, Fabian; Cha, Yong-Ho; Jeong, Do-Young; Lee, Sang Bae; Lee, Kwanil; Yeom, Dong-Il

    2016-06-27

    We demonstrate an all-fiber Tm-doped soliton laser with high power by using a monolayer graphene saturable absorber (SA). Large area, uniform monolayer graphene was transferred to the surface of the side-polished fiber (SPF) to realize an in-line graphene SA that operates around 2 μm wavelength. To increase the nonlinear interaction with graphene, we applied an over-cladding onto the SPF, where enhanced optical absorption at monolayer graphene was observed. All-fiber Tm-doped mode-locked laser was built including our in-line graphene SA, which stably delivered the soliton pulses with 773 fs pulse duration. The measured 3-dB spectral bandwidth was 5.14 nm at the wavelength of 1910 nm. We obtained the maximum average output power of 115 mW at a repetition rate of 19.31 MHz. Corresponding pulse energy was estimated to be 6 nJ, which is the highest value among all-fiber Tm-doped soliton oscillators using carbon-material-based SAs.

  19. Response of soil biota to vineyard interrow soil cultivation can be altered by the surrounding landscape

    Science.gov (United States)

    Zaller, Johann; Buchholz, Jacob; Querner, Pascal; Paredes, Daniel; Kratschmer, Sophie; Schwantzer, Martina; Winter, Silvia; Strauss, Peter; Bauer, Thomas; Burel, Françoise; Guernion, Muriel; Scimia, Jennifer; Nicolai, Annegret; Cluzeau, Daniel

    2017-04-01

    Ecosystem services provided by viticultural landscapes result from interactions between management intensity, soil properties, organisms inhabiting these landscapes, and the diversity and structure of the surrounding landscape. However, there is actually very little known to what extent these different factors influence the abundance and diversity of various soil biota. In this study we examined (i) to what extent different soil management intensities of interrows affect the activity and diversity of soil biota (earthworms, Collembola, litter decomposition), (ii) the role of soil properties in influencing these effects and (iii) whether the surrounding landscape structure is altering these interactions. We collected data in 16 vineyards in Austria embedded in landscapes with varying structure (i.e. from structurally simple to complex) and assessed earthworms (hand sorting), Collembola (pitfall trapping and soil coring), litter decomposition (tea bag method). Additionally, soil physical (water infiltration, aggregate stability, porosity, bulk density, soil texture) and chemical (pH, soil carbon content, cation exchange capacity, potassium, phosphorus) parameters were assessed. The landscape surrounding our vineyards within a radius of 750 m was assessed by field mapping using a geographical information system. Results showed that different soil biota/processes are differently affected by soil cultivation intensity and soil properties. Parameters describing the surrounding landscape interacted more with the responses of Collembola to soil cultivation than with earthworms or litter decomposition. These investigations are part of the transdisciplinary BiodivERsA project VineDivers (www.vinedivers.eu) and will ultimately lead into management recommendations for various stakeholders.

  20. Evaluation of thin discontinuities in planar conducting materials using the diffraction of electromagnetic field

    Science.gov (United States)

    Savin, A.; Novy, F.; Fintova, S.; Steigmann, R.

    2017-08-01

    The current stage of nondestructive evaluation techniques imposes the development of new electromagnetic (EM) methods that are based on high spatial resolution and increased sensitivity. In order to achieve high performance, the work frequencies must be either radifrequencies or microwaves. At these frequencies, at the dielectric/conductor interface, plasmon polaritons can appear, propagating between conductive regions as evanescent waves. In order to use the evanescent wave that can appear even if the slits width is much smaller that the wavwelength of incident EM wave, a sensor with metamaterial (MM) is used. The study of the EM field diffraction against the edge of long thin discontinuity placed under the inspected surface of a conductive plate has been performed using the geometrical optics principles. This type of sensor having the reception coils shielded by a conductive screen with a circular aperture placed in the front of reception coil of emission reception sensor has been developed and “transported” information for obtaining of magnified image of the conductive structures inspected. This work presents a sensor, using MM conical Swiss roll type that allows the propagation of evanescent waves and the electromagnetic images are magnified. The test method can be successfully applied in a variety of applications of maxim importance such as defect/damage detection in materials used in automotive and aviation technologies. Applying this testing method, spatial resolution can be improved.

  1. Eccrine syringofibroadenoma surrounding a squamous cell carcinoma: a case report.

    Science.gov (United States)

    Lele, S M; Gloster, E S; Heilman, E R; Chen, P C; Chen, C K; Anzil, A P; Pozner, J N; Reardon, M J

    1997-03-01

    A 91-year-old man presented with a 9.0 x 7.0 cm exophytic mass on the dorsum of the right foot, surrounded by a scaling hyperkeratotic plaque-like lesion that had been present for many years. He had similar long-standing hyperkeratotic plaque-like lesions on both legs. Histopathologic examination of the exophytic mass revealed a well-differentiated squamous cell carcinoma surrounded by an eccrine syringofibroadenoma (ESFA). Histochemistry, immunohistochemistry and electron microscopy support this diagnosis. To our knowledge, this is the only reported case of ESFA being intimately associated with a malignant neoplasm.

  2. Online sensing of volatile organic compounds in groundwater using mid-infrared fibre optic evanescent wave spectroscopy: a pilot scale test.

    Science.gov (United States)

    Steiner, H; Staubmann, K; Allabashi, R; Fleischmann, N; Katzir, A; Reichlin, Y; Milzaikoff, B

    2003-01-01

    A prototype sensing system for in-situ monitoring of volatile organic compounds in contaminated groundwater was tested at a pilot scale plant. The sensor consists of a commercially available Fourier transform infrared spectrometer, connected to a 6 m long infrared transparent silver halide fibre optic cable. A 10 cm long core-only section at the centre of the fibre is mounted on a sensor head and coated with a hydrophobic polymer layer, while the remaining fibre is protected by Teflon tubing and thus not in contact with the surrounding media. The sensor head was immersed into the monitoring wells of the pilot plant testing the sensor system under circumstances close to field conditions and typical for in-situ measurements. The pilot plant consists of a 1 m3 cubic tank filled with gravel. A pump is used to circulate water horizontally through the tank, simulating a natural aquifer. The evolution of the concentration of analytes injected into the system is monitored with time using the developed prototype sensing system. The results are validated by corresponding sampling and analysis with headspace gas chromatography.

  3. Confronting, Confirming, and Dispelling Myths Surrounding ERP-in-the-Cloud

    DEFF Research Database (Denmark)

    Beaulieu, Tanya; C. Martin, Todd; Sarker, Saonee

    2015-01-01

    understanding about the true challenges related to ERP cloud computing, it is important to examine these myths in an effort to dispel or support them. In this paper, we attempt to achieve that. Specifically, we explore eight myths related to cloud-based ERP systems through a study involving in-depth interviews......Although cloud computing is still in its infancy, it is rapidly becoming one of the most used buzzwords in the IS/IT field and ERP-systems are one of the fastest growing SaaS cloud applications. However, given the relative newness of ERP cloud computing, and the lack of empirical research...... on the topic, there is substantial uncertainty surrounding the benefits and challenges of ERP cloud computing. Consequently, as often is the case with new technologies, popular myths surrounding the technology are used to make adoption and implementation decisions. As a first step toward providing an informed...

  4. Real-time and low-cost embedded platform for car's surrounding vision system

    Science.gov (United States)

    Saponara, Sergio; Franchi, Emilio

    2016-04-01

    The design and the implementation of a flexible and low-cost embedded system for real-time car's surrounding vision is presented. The target of the proposed multi-camera vision system is to provide the driver a better view of the objects that surround the vehicle. Fish-eye lenses are used to achieve a larger Field of View (FOV) but, on the other hand, introduce radial distortion of the images projected on the sensors. Using low-cost cameras there could be also some alignment issues. Since these complications are noticeable and dangerous, a real-time algorithm for their correction is presented. Then another real-time algorithm, used for merging 4 camera video streams together in a single view, is described. Real-time image processing is achieved through a hardware-software platform

  5. A 500 PARSEC HALO SURROUNDING THE GALACTIC GLOBULAR NGC 1851

    NARCIS (Netherlands)

    Olszewski, Edward W.; Saha, Abhijit; Knezek, Patricia; Subramaniam, Annapurni; de Boer, Thomas; Seitzer, Patrick

    2009-01-01

    Using imaging that shows 4 mag of main-sequence stars, we have discovered that the Galactic globular cluster NGC 1851 is surrounded by a halo that is visible from the tidal radius of 700 arcsec (41 pc) to more than 4500 arcsec (> 250 pc). This halo is symmetric and falls in density as a power law of

  6. Influence of surroundings on photorefractive effect in lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Tarjanyi, Norbert, E-mail: tarjanyi@fyzika.uniza.sk [Department of Physics, Faculty of Electrical Engineering, University of Zilina, Univerzitna 1, Zilina, 01026 (Slovakia); Turek, Ivan [Berlinska 4, Zilina, 01008 (Slovakia)

    2012-11-01

    In the paper results of the investigation of the influence of electric properties of the environment surrounding LiNbO{sub 3} crystals on photorefractive effect induced in these crystals by Gaussian Ar{sup +} laser beam with various intensities are presented. We show spatial and temporal dependences of changes of the refractive index obtained experimentally in LiNbO{sub 3}: Fe and LiNbO{sub 3}: Fe:Mn samples surrounded by media with different electric conductivities and different permittivities (water, air, water solution of CaCl{sub 2}). The space and time dependences of the refractive index changes induced by the Ar{sup +} laser beam are observed by means of the Mach-Zehnder interferometer using light from HeNe laser. The experimentally obtained results are in a good agreement with those following from numerical calculations using the manifold mirroring method. The agreement between calculated and experimental results indicates that the polarization charge at the photorefractive crystal/surrounding medium boundary significantly influences the photorefractive process in the crystal. The experimentally observed slow spontaneous decrease of the refractive index change in a sample placed into a slightly conducting medium (air) after switching off the beam also indicates that the polarization charge in the sample's surroundings affects the photorefraction.

  7. Placental vascular responses are dependent on surrounding tissue

    DEFF Research Database (Denmark)

    Brøgger, Torbjørn Halle

    . Materials and methods. From fresh born placentas, stem villi arteries were carefully dissected. The artery branches were divided. The surrounding tissue was removed from one end and was left untouched in the other end.Then, using wire myography, they were investigated in terms of contractility...

  8. Acrylate in Phaeocystis colonies does not affect the surrounding bacteria

    NARCIS (Netherlands)

    Noordkamp, DJB; Gieskes, WWC; Gottschal, JC; Forney, LJ; van Rijssel, M

    Acrylate accumulates to concentrations of 1.3-6.5 mM in the mucus of Phaeocystis colonies and may have an effect on the surrounding bacterial community, either as an inhibitor or as a carbon source. Both in the held and in the laboratory, effects of acrylate on bacterial growth and on its

  9. Traditional Indian customs surrounding birth A review | Chalmers ...

    African Journals Online (AJOL)

    Since 1960, only a few studies have been made of traditional custOIns surrounding birth in Indian culture. Very few of these have described customs followed by Indians in South Africa. A review of these publications is presented here. Customs described include religious, social and psychological aspects of behaviour in ...

  10. Smart Signs: Showing the way in Smart Surroundings

    NARCIS (Netherlands)

    Lijding, M.E.M.; Benz, H.P.; Meratnia, Nirvana; Havinga, Paul J.M.

    This paper presents a context-aware guidance and messaging system for large buildings and surrounding venues. Smart Signs are a new type of electronic door- and way-sign based on wireless sensor networks. Smart Signs present in-situ personalized guidance and messages, are ubiquitous, and easy to

  11. Review of Ordered Anarchy: Jasay and his Surroundings

    Directory of Open Access Journals (Sweden)

    Aschwin de Wolf

    2009-02-01

    Full Text Available Anthony de Jasay is among the most important social thinkers of our time. His oeuvre offers a sustained critique of government and its defenders. In the book Ordered Anarchy: Jasay and His Surroundings, colleagues and friends pay tribute to the man in the form of an inspiring collection of essays.

  12. Polluted Alamuyo River: Impacts on surrounding wells, microbial ...

    African Journals Online (AJOL)

    Polluted Alamuyo River: Impacts on surrounding wells, microbial attributes and toxic effects on Allium cepa root cells. ... High microbial load was observed in river water samples compared to the well water samples throughout the sampling periods with overall highest value observed at Late Rainy Season upstream water ...

  13. Linking disadvantaged housing areas to the surrounding city

    DEFF Research Database (Denmark)

    Stender, Marie

    Several disadvantaged social housing areas in Denmark are currently undergo-ing thorough physical refurbishments, aiming to integrate them better with the surrounding city. The ambition is to attract new users and residents by opening up the borders of the area and establish attractive, new...

  14. Numerical Methods in Electromagnetics: Evanescent Nanometry for DNA Sequencing, and EM Induction for UXO Detection and Discrimination

    Science.gov (United States)

    Bijamov, Alex

    The main goals of this work are to extend forward and apply inverse EM numerical methods to enhance the fundamental understanding of ultra-wideband frequency range EM fields in complex geometries. The particular emphases are made on medical device development for whole human genome sequencing using force spectroscopy; and underwater target detection, and live sites UXO discrimination. Force spectroscopy is a powerful technique used to manipulate single biomolecules and study their interactions. In these experiments one end of a macromolecule is immobilized on a substrate, while its free end is attached to an externally-manipulated microscopic bead. Crucial to the application of force spectroscopy to DNA sequencing is the ability to apply pulling forces reaching hundreds of pico-Newtons and image molecular extensions with sub-nanometer resolution. To achieve both goals the behavior of EM fields in the vicinity of the beads and the associated far fields need to be investigated using numerical simulations. In recent years our group has developed a numerical technique---the Method of Auxiliary Sources---which was modified here for these problems. In this work the physics of bead scattering and fluorescent responses is studied for a variety of bead and substrate compositions and geometries, including layered structures, to understand their potential in increasing imaging sensitivity. This thesis also studies the inversion problems related to the underwater UXO detection and live-site UXO discrimination. Rigorous analysis of underlying physics of low-frequency EM field scattering from conducting objects in underwater environments is performed. The effects of seawater surface roughness on transmitted EM signals and the associated noise levels are analyzed. A new, magnetic field-based geolocation system is studied numerically for GPS-denied underwater environments. Finally, the performances of statistical and machine learning methods are analyzed for automatic

  15. HUBBLE FINDS THOUSANDS OF GASEOUS FRAGMENTS SURROUNDING DYING STAR

    Science.gov (United States)

    2002-01-01

    Resembling a bizarre setting from a science fiction movie, dramatic images sent back by NASA's Hubble Space Telescope have surprised astronomers by uncovering thousands of gigantic tadpole-shaped objects surrounding a dying star. Dubbed 'cometary knots' because their glowing heads and gossamer tails superficially resemble comets, they are probably the result of a dying star's final outbursts. Though ground-based telescopic observations have hinted at such objects, they have not previously been seen in such abundance, say researchers. The knots were detected by Hubble astronomer C. Robert O'Dell and graduate student Kerry P. Handron of Rice University in Houston, Texas, while exploring the Helix nebula, a ring of glowing gases blown off the surface of a sunlike star late in its life. O'Dell expects the gaseous knots, which are each several billion miles across, will eventually dissipate and vanish into the cold emptiness of interstellar space. However, he speculates that if the objects contract to form permanent solid bodies, they may contribute to a fraction (less than ten percent) of the missing mass of our galaxy, simply because of their sheer abundance around a typical dying star. (This so-called dark matter is a known source of gravity that affects the motions of stars in the galaxy). The mysterious 'space pods' came into view as O'Dell used Hubble's Wide Field Planetary Camera 2 to survey the Helix nebula, located 450 light-years away in the constellation Aquarius and the closest planetary nebula to Earth -- so close that its angular size is almost half that of the full Moon. The most visible cometary knots all lie along the inner edge of the ring, at a distance of trillions of miles from the central star. Their comet-like tails, each stretching a hundred billion miles, form a radial pattern around the star like the spokes on a wagon wheel. Though previous ground-based observations show a spoke pattern in the Helix, and some structure, O'Dell emphasizes that

  16. Fiber optic NIR evanescent wave absorption sensor systems for in-situ monitoring of hydrocarbon compounds in waste and ground water

    Science.gov (United States)

    Buerck, Jochen; Denter, P.; Mensch, M.; Kraemer, K.; Scholz, Michael

    1999-02-01

    In situ measurements with the prototype of a portable fiber- optic sensor system for the monitoring of nonpolar hydrocarbons (HC) in ground water or industrial waste water are presented. This sensor system can be used for quantitative in situ analysis of pollutants such as aromatic solvents, fuels, mineral oils or chlorinated HCs in a broad concentration range from around 200 (mu) g(DOT) L-1 up to a few 100 mg(DOT) L-1. The sensing principle is based on solid phase extraction of analyte molecules into a hydrophobic silicone cladding of a quartz glass optical fiber and the direct absorptiometric measurement of the extracted species in the polymer through the evanescent wave. The sensor can be connected via all-silica fibers with a length of up to 100 m to a filter photometer developed at the IFIA, thus allowing even remote analysis in monitoring wells. This instrument provides a sum concentration signal of the extracted organic compounds by measuring the integral absorption at the C-H overtone bands in the near-infrared spectral range. In situ measurements with the sensor system were performed in a ground water circulation well at the VEGAS research facility (Universitat Stuttgart). Here, the sensor proved to trace the HC sum concentration of xylene isomers in process water pumped from the well to a stripper column. In further experiments the sensor was combined with an oil sampling device and was tested with simulated waste waters of a commercial vehicle plant contaminated with different types of mineral oil. In this case the sensor system was able to detect the presence of mineral oil films floating on water or oil-in-water emulsions with concentrations greater than 20 ppm (v/v) within a few minutes.

  17. Kinetic theory of plasma sheaths surrounding electron-emitting surfaces.

    Science.gov (United States)

    Sheehan, J P; Hershkowitz, N; Kaganovich, I D; Wang, H; Raitses, Y; Barnat, E V; Weatherford, B R; Sydorenko, D

    2013-08-16

    A one-dimensional kinetic theory of sheaths surrounding planar, electron-emitting surfaces is presented which accounts for plasma electrons lost to the surface and the temperature of the emitted electrons. It is shown that ratio of plasma electron temperature to emitted electron temperature significantly affects the sheath potential when the plasma electron temperature is within an order of magnitude of the emitted electron temperature. The sheath potential goes to zero as the plasma electron temperature equals the emitted electron temperature, which can occur in the afterglow of an rf plasma and some low-temperature plasma sources. These results were validated by particle in cell simulations. The theory was tested by making measurements of the sheath surrounding a thermionically emitting cathode in the afterglow of an rf plasma. The measured sheath potential shrunk to zero as the plasma electron temperature cooled to the emitted electron temperature, as predicted by the theory.

  18. Trajectories and Maneuvers of Surrounding Vehicles with Panoramic Camera Arrays

    DEFF Research Database (Denmark)

    Dueholm, Jacob Velling; Kristoffersen, Miklas Strøm; Satzoda, Ravi K.

    2016-01-01

    of drive on US highways. The multiperspective tracker is tested in each view as well as for the ability to associate vehicles bet-ween views with a 92% recall score. A case study of vehicles approaching from the rear shows certain patterns in behavior that could potentially influence the ego-vehicle.......Vision-based research for intelligent vehicles have traditionally focused on specific regions around a vehicle, such as a front looking camera for, e.g., lane estimation. Traffic scenes are complex and vital information could be lost in unobserved regions. This paper proposes a framework that uses...... four visual sensors for a full surround view of a vehicle in order to achieve an understanding of surrounding vehicle behaviors. The framework will assist the analysis of naturalistic driving studies by automating the task of data reduction of the observed trajectories. To this end, trajectories...

  19. Belief and Attitudes surrounding Childhood Autism in Ghana

    OpenAIRE

    Manu, Naomi

    2012-01-01

    Autism is a life-long invisible impairment with an unknown etiology. Current literature shows an increase in the diagnosis of autism worldwide. This qualitative study explores the attitudes and beliefs which surround childhood autism in Ghana. In-depth interviews were conducted with four (4) parents whose children have autism and three (3) key informants; a Religious Leader, a Health Worker and an Administrator of a Special school in Accra, Ghana. A semi-structured interview guide was used fo...

  20. Tissue reaction surrounding miniscrews for orthodontic anchorage: An animal experiment

    Directory of Open Access Journals (Sweden)

    Stephanie Shih-Hsuan Chen

    2012-03-01

    Results and conclusions: (1 Tissue surrounding roots damaged by a miniscrew showed a significant inflammatory response. (2 Root resorption was occasionally observed after 3 weeks following insertion of a miniscrew even if the miniscrew was not in direct contact with the root. (3 Root repair was noted with a cementoblast lining along the resorption surface at as early as 3 weeks after miniscrew insertion. Alveolar bone filled in the lesion when the root damage was large so that the contour of the alveolar bone followed that of the damaged root, with the width of the periodontal ligament space being maintained. (4 Stable miniscrews were mainly those which did not contact adjacent roots, and for which the surrounding tissue showed only a small inflammatory response with some extent of direct bone contact around the miniscrew. On the contrary, most of the failed miniscrews were those which had direct contact with adjacent roots, and which exhibited severe tissue inflammation and were covered by thick layers of soft tissue. Failure was detected 3 weeks after insertion. Surprisingly, the epithelial lining surrounding the miniscrews might not have spontaneously resolved 6 weeks after screw removal. Persistent infection in the sinus tract was noted, and this would require attention.

  1. A Continuous Current Model of Accumulation Mode (Junctionless) Cylindrical Surrounding-Gate Nanowire MOSFETs

    Science.gov (United States)

    Jin, Xiao-Shi; Liu, Xi; Kwon, Hyuck-In; Lee, Jong-Ho

    2013-03-01

    A continuous current model of accumulation mode or so-called junctionless (JL) cylindrical surrounding-gate Si Nanowire metal-oxide-silicon field effect transistors (MOSFETs) is proposed. The model is based on an approximated solution of Poisson's equation considering both body doping and mobile charge concentrations. It is verified by comparing with three-dimensional simulation results using SILVACO Atlas TCAD which shows good agreement. Without any empirical fitting parameters, the proposed continuous current model of JL SRG MOSFETs is valid for all the operation regions.

  2. Design, fabrication and characterization of a Far-field Superlens

    Science.gov (United States)

    Lee, Hyesog; Liu, Zhaowei; Xiong, Yi; Sun, Cheng; Zhang, Xiang

    2008-05-01

    The fabrication process as well as the optical characterization of a Far-field Superlens (FSL) is presented in detail. A FSL is capable of optically imaging well below the diffraction limit and works by enhancing and scattering evanescent waves to the far field which is then used to numerically reconstruct the object image [S. Durant, J. Opt. Soc. Am. B. 23(2006) 2383; Z. Liu, S. Durant, H. Lee, Y. Pikus, N. Fang, Y. Xiong, C. Sun, X. Zhang, Nano Lett. 7 (2007) 403]. We demonstrate the resolution of 70 nm gap distance of a three-line object in the far field. Also, a full optical imaging scheme, without the need for numerical processing, for a direct real-time subdiffraction-limited imaging is presented. Such remarkable imaging capability of FSL will revolutionize the optical imaging technique in the field of bio-imaging and nanolithography.

  3. Numerical studies on surrounding rock deformation controlled by pressure relief groove in deep roadway

    Science.gov (United States)

    Liu, Chaoke; Ren, Jianxi; Zhang, Kun; Chen, Shaojie

    2017-05-01

    After entering deep mining, the roadway is in a high stress state, the deformation of surrounding rock becomes larger, and the roadway floor is particularly significant under unsupported state, which brings great difficulty to the safe production and support of the coal mine. Pressure relief method can change the stress field of surrounding rocks so that the surrounding rock can be in stress-reducing area. The present paper studied the deformation law of the roadway and the changes in the stress state and plastic zone of the surrounding rocks around the roadway before and after the excavation of pressure relief groove on the bottom floor of the high-stress roadway by using FLAC under the engineering background of one mine in Binchang, analyzed the influence of different groove depths and widths on the floor heave, convergence on both sides and roof subsidence. The simulation results show that: after the roadway floor was grooved in the high stress roadway, a larger stress-relaxed area will be formed near the roadway floor, the stress will be transferred to the deep roadway floor, and the pressure relief groove plays a better control effect on the deformation of the high-stress roadway. With the increase of the width and depth of the pressure relief groove, the convergence of the top and bottom of the roadway will be decreased accordingly, but the effect is not significant, while its influence on the convergence on both sides is relatively significant. After applying the simulation results to the engineering practice, the practice shows that: the combined support of anchor rod, anchor rope plus pressure relief groove can control the deformation of the roadway well and the conclusion obtained can provide some reference values for the study and design of the grooving pressure relief control technology.

  4. Summertime ozone formation in Xi'an and surrounding areas, China

    Directory of Open Access Journals (Sweden)

    T. Feng

    2016-04-01

    Full Text Available In this study, the ozone (O3 formation in China's northwest city of Xi'an and surrounding areas is investigated using the Weather Research and Forecasting atmospheric chemistry (WRF-Chem model during the period from 22 to 24 August 2013, corresponding to a heavy air pollution episode with high concentrations of O3 and PM2.5. The model generally performs well compared to measurements in simulating the surface temperature, relative humidity, and wind speed and direction, near-surface O3 and PM2.5 mass concentrations, and aerosol constituents. High aerosol concentrations in Xi'an and surrounding areas significantly decrease the photolysis frequencies and can reduce O3 concentrations by more than 50 µg m−3 (around 25 ppb on average. Sensitivity studies show that the O3 production regime in Xi'an and surrounding areas is complicated, varying from NOx to VOC (volatile organic compound-sensitive chemistry. The industrial emissions contribute the most to the O3 concentrations compared to biogenic and other anthropogenic sources, but neither individual anthropogenic emission nor biogenic emission plays a dominant role in the O3 formation. Under high O3 and PM2.5 concentrations, a 50 % reduction in all the anthropogenic emissions only decreases near-surface O3 concentrations by about 14 % during daytime. The complicated O3 production regime and high aerosol levels pose a challenge for O3 control strategies in Xi'an and surrounding areas. Further investigation regarding O3 control strategies will need to be performed, taking into consideration the rapid changes in anthropogenic emissions that are not reflected in the current emission inventories and the uncertainties in the meteorological field simulations.

  5. INTERACTIONS OF THE INFRARED BUBBLE N4 WITH ITS SURROUNDINGS

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hong-Li; Li, Jin-Zeng; Yuan, Jing-Hua; Huang, Maohai; Huang, Ya-Fang; Zhang, Si-Ju [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Wu, Yuefang [Department of Astronomy, Peking University, 100871 Beijing (China); Liu, Tie [Korea Astronomy and Space Science Institute 776, Daedeokdae-ro, Yuseong-gu, Daejeon, 305-348 (Korea, Republic of); Dubner, G.; Paron, S.; Ortega, M. E. [1Instituto de Astronomía y Física del Espacio (IAFE, CONICET-UBA), CC 67, Suc. 28, 1428 Buenos Aires (Argentina); Molinari, Sergio [Istituto di Astrofisica e Planetologia Spaziali—IAPS, Istituto Nazionale di Astrofisica—INAF, via Fosso del Cavaliere 100, I-00133 Roma (Italy); Zavagno, Annie; Samal, Manash R., E-mail: hlliu@nao.cas.cn [Aix Marseille Universit, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388, Marseille (France)

    2016-02-10

    The physical mechanisms that induce the transformation of a certain mass of gas in new stars are far from being well understood. Infrared bubbles associated with H ii regions have been considered to be good samples for investigating triggered star formation. In this paper we report on the investigation of the dust properties of the infrared bubble N4 around the H ii region G11.898+0.747, analyzing its interaction with its surroundings and star formation histories therein, with the aim of determining the possibility of star formation triggered by the expansion of the bubble. Using Herschel PACS and SPIRE images with a wide wavelength coverage, we reveal the dust properties over the entire bubble. Meanwhile, we are able to identify six dust clumps surrounding the bubble, with a mean size of 0.50 pc, temperature of about 22 K, mean column density of 1.7 × 10{sup 22} cm{sup −2}, mean volume density of about 4.4 × 10{sup 4} cm{sup −3}, and a mean mass of 320 M{sub ⊙}. In addition, from PAH emission seen at 8 μm, free–free emission detected at 20 cm, and a probability density function in special regions, we could identify clear signatures of the influence of the H ii region on the surroundings. There are hints of star formation, though further investigation is required to demonstrate that N4 is the triggering source.

  6. No evidence for active human papillomavirus (HPV) in fields surrounding HPV-positive oropharyngeal tumors

    NARCIS (Netherlands)

    Rietbergen, M.M.; Braakhuis, B.J.M.; Moukhtari, N.; Bloemena, E.; Brink, A.; Sie, D.; Ylstra, B.; Baatenburg de Jong, R.J.; Snijders, P.J.F.; Brakenhoff, R.H.; Leemans, C.R.

    2014-01-01

    Background Patients with human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinomas (OPSCCs) have a better prognosis than patients with HPV-negative OPSCCs. Important factors contributing to this better prognosis are relatively low numbers of local/regional recurrences (LRRs) and

  7. Extending results from agricultural fields with intensively monitored data to surrounding areas for water quality management

    Science.gov (United States)

    A 45% reduction in riverine total nitrogen flux from the 1980-1996 time period is needed to meet water quality goals in the Mississippi Basin and Gulf of Mexico. This paper addresses the goal of reducing nitrogen in the Mississippi River through three objectives. First, the paper outlines an approac...

  8. Spirit's Surroundings on 'West Spur,' Sol 305 (Vertical)

    Science.gov (United States)

    2005-01-01

    This 360-degree panorama shows the terrain surrounding NASA's Mars Exploration Rover Spirit as of the rover's 305th martian day, or sol, (Nov. 11, 2004). At that point, Spirit was climbing the 'West Spur' of the 'Columbia Hills.' The rover had just finished inspecting a rock called 'Lutefisk' and was heading uphill toward an area called 'Machu Picchu.' Spirit used its navigational camera to take the images combined into this mosaic. The rover's location when the images were taken is catalogued as the mission's site 89, position 205. The view is presented here as a vetical projection with geometric seam correction.

  9. Spirit's Surroundings on 'West Spur,' Sol 305 (Polar)

    Science.gov (United States)

    2005-01-01

    This 360-degree panorama shows the terrain surrounding NASA's Mars Exploration Rover Spirit as of the rover's 305th martian day, or sol, (Nov. 11, 2004). At that point, Spirit was climbing the 'West Spur' of the 'Columbia Hills.' The rover had just finished inspecting a rock called 'Lutefisk' and was heading uphill toward an area called 'Machu Picchu.' Spirit used its navigational camera to take the images combined into this mosaic. The rover's location when the images were taken is catalogued as the mission's site 89, position 205. The view is presented here as a polar projection with geometric seam correction.

  10. Induced radioactivity in a 4 MW target and its surroundings

    CERN Document Server

    Agosteo, Stefano; Otto, Thomas; Silari, Marco

    2003-01-01

    An important aspect of a future CERN Neutrino Factory is the material activation arising from a 2.2 GeV, 4 MW proton beam striking a mercury target. An estimation of the hadronic inelastic interactions and the production of residual nuclei in the target, the magnetic horn, the decay tunnel, the surrounding rock and a downstream dump was performed by the Monte Carlo hadronic cascade code FLUKA. The aim was both to assess the dose equivalent rate to be expected during maintenance work and to evaluate the amount of residual radioactivity, which will have to be disposed of after the facility has ceased operation.

  11. Current leakage for low altitude satellites. [to surrounding plasma sheath

    Science.gov (United States)

    Mccoy, J. E.; Konradi, A.; Garriott, O. K.

    1979-01-01

    Ionospheric plasma densities exceeding 1,000,000 per cu cm exist around satellites in low earth orbit. Operation of large solar arrays at high voltage may drive substantial leakage currents through this surrounding plasma. Power losses exceeding solar cell output have been observed for small arrays biased above +2,000 V. Estimates of these effects for very large power systems are developed. Recent large scale (10 meter) lab tests are reported. Estimates based on calculations of space charge limited sheath dimensions are identified as a good working model, leading to projected power losses for large arrays increasing much more slowly than for small arrays.

  12. The science and questions surrounding chronic traumatic encephalopathy.

    Science.gov (United States)

    Ban, Vin Shen; Madden, Christopher J; Bailes, Julian E; Hunt Batjer, H; Lonser, Russell R

    2016-04-01

    Recently, the pathobiology, causes, associated factors, incidence and prevalence, and natural history of chronic traumatic encephalopathy (CTE) have been debated. Data from retrospective case series and high-profile media reports have fueled public fear and affected the medical community's understanding of the role of sports-related traumatic brain injury (TBI) in the development of CTE. There are a number of limitations posed by the current evidence that can lead to confusion within the public and scientific community. In this paper, the authors address common questions surrounding the science of CTE and propose future research directions.

  13. Mutual seismic interaction between tunnels and the surrounding granular soil

    Directory of Open Access Journals (Sweden)

    Mohamed Ahmed Abdel-Motaal

    2014-12-01

    Study results show that the maximum exerted straining actions in tunnel lining are directly proportional to the relative stiffness between tunnel and surrounding soil (lining thickness and soil shear modulus. Moreover, it is highly affected by the peak ground acceleration and the tunnel location (embedment depth. A comprehensive study is performed to show the effect of tunnel thickness and tunnel diameter on both the induced bending moment and lining deformation. In general, it is concluded that seismic analysis should be considered in regions subjected to peak ground acceleration greater than 0.15g.

  14. Crustal structure beneath Beijing and its surrounding regions derived from gravity data

    Science.gov (United States)

    Jiang, Wenliang; Zhang, Jingfa; Lu, Xiaocui; Lu, Jing

    2011-06-01

    In this paper we use gravity data to study fine crustal structure and seismogenic environment beneath Beijing and its surrounding regions. Multi-scale wavelet analysis method is applied to separating gravity fields. Logarithmic power spectrum method is also used to calculate depth of gravity field source. The results show that the crustal structure is very complicated beneath Beijing and its surrounding areas. The crustal density exhibits laterally inhomogeneous. There are three large scale tectonic zones in North China, i.e., WNW-striking Zhangjiakou-Bohai tectonic zone (ZBTZ), NE-striking Taihang piedmont tectonic zone (TPTZ) and Cangxian tectonic zone (CTZ). ZBTZ and TPTZ intersect with each other beneath Beijing area and both of them cut through the lithosphere. The upper and middle crusts consist of many small-scale faults, uplifts and depressions. In the lower crust, these small-scale tectonic units disappear gradually, and they are replaced by large-scale tectonic units. In surrounding regions of Beijing, ZBTZ intersects with several other NE-striking tectonic units, such as Cangxian uplift, Jizhong depression and Shanxi Graben System (SGS). In west of Taihangshan uplift, gravity anomalies in upper and middle crusts are correlated with geological and topographic features on the surface. Compared with the crust, the structure is comparatively simple in uppermost mantle. Earthquakes mainly occurred in upper and middle crusts, especially in transitional regions between high gravity anomaly and low gravity anomaly. Occurrence of large earthquakes may be related to the upwelling of upper mantle and asthenosphere heat flow materials, such as Sanhe earthquake ( M S8.0) and Tangshan earthquake ( M S7.8).

  15. Effectively Communicating the Uncertainties Surrounding Ebola Virus Transmission.

    Science.gov (United States)

    Kilianski, Andy; Evans, Nicholas G

    2015-10-01

    The current Ebola virus outbreak has highlighted the uncertainties surrounding many aspects of Ebola virus virology, including routes of transmission. The scientific community played a leading role during the outbreak-potentially, the largest of its kind-as many of the questions surrounding ebolaviruses have only been interrogated in the laboratory. Scientists provided an invaluable resource for clinicians, public health officials, policy makers, and the lay public in understanding the progress of Ebola virus disease and the continuing outbreak. Not all of the scientific communication, however, was accurate or effective. There were multiple instances of published articles during the height of the outbreak containing potentially misleading scientific language that spurred media overreaction and potentially jeopardized preparedness and policy decisions at critical points. Here, we use articles declaring the potential for airborne transmission of Ebola virus as a case study in the inaccurate reporting of basic science, and we provide recommendations for improving the communication about unknown aspects of disease during public health crises.

  16. Microbial communities associated with ferromanganese nodules and the surrounding sediments

    Directory of Open Access Journals (Sweden)

    Benjamin John Tully

    2013-06-01

    Full Text Available The formation and maintenance of deep-sea ferromanganese/polymetallic nodules still remains a mystery 140 years after their discovery. The wealth of rare metals concentrated in these nodules has spurred global interest in exploring the mining potential of these resources. The prevailing theory of abiotic formation has been called into question and the role of microbial metabolisms in nodule development is now an area of active research. To understand the community structure of microbes associated with nodules and their surrounding sediment, we performed targeted sequencing of the V4 hypervariable region of the 16S rRNA gene from three nodules collected from the central South Pacific. Results have shown that the microbial communities of the nodules are significantly distinct from the communities in the surrounding sediments, and that the interiors of the nodules harbor communities different from the exterior. This suggests not only differences in potential metabolisms between the nodule and sediment communities, but also differences in the dominant metabolisms of interior and exterior communities. We identified several operational taxonomic units (OTUs unique to both the nodule and sediment environments. The identified OTUs were assigned putative taxonomic identifications, including two OTUs only found associated with the nodules, which were assigned to the α-Proteobacteria. Finally, we explored the diversity of the most assigned taxonomic group, the Thaumarchaea MG-1, which revealed novel OTUs compared to previous research from the region and suggests a potential role as a source of fixed carbon for ammonia oxidizing archaea in the environment.

  17. REMOTE SENSING EFFICIENCY FOR URBAN ANALYSIS OF MECCA AND SURROUNDS

    Directory of Open Access Journals (Sweden)

    A. Imam

    2016-06-01

    Full Text Available Situated in the southwest of Saudi Arabia, Mecca is considered the spiritual capital of one and a half billion worldwide Muslims. The city is visited by millions of pilgrims every year. It has undergone significant changes in land cover (LC since the government first embarked on a series of ambitious development projects 20 years ago to accommodate the growing number of pilgrims and citizens. The main objective of our study is to detect, identify, analyze and measure the evolving land cover and urban morphology composition from multi-temporal satellite images. To characterize the morphological change during a period of twenty years, four satellite images, acquired in 1998 by Landsat TM and in 2003, 2008 and 2013 by Landsat ETM+, were classified into five main categories: Urban, Street, Soil and Vegetation. In addition, DEM has been extracted and included as Mountain. Change detection (CD analysis is applied using post-classification comparison and GIS. As part of the study, morphological index, such as, Entropy is included for better understanding of urban structures behaviour. Mecca and its surroundings show a noticeable increase in urban and vegetation cover. Urban cover (UC changes were divided into five radial directions: Northeast, Southeast, Southwest, East, and Northwest. These changes are influenced by mountain ranges surrounding the city and the highways. These revelations can play a significant role towards future planning and development activities, which may further promote urban growth.

  18. Remote Sensing Efficiency for Urban Analysis of Mecca and Surrounds

    Science.gov (United States)

    Imam, Ayman; Alhaddad, Bahaa; Roca, Josep

    2016-06-01

    Situated in the southwest of Saudi Arabia, Mecca is considered the spiritual capital of one and a half billion worldwide Muslims. The city is visited by millions of pilgrims every year. It has undergone significant changes in land cover (LC) since the government first embarked on a series of ambitious development projects 20 years ago to accommodate the growing number of pilgrims and citizens. The main objective of our study is to detect, identify, analyze and measure the evolving land cover and urban morphology composition from multi-temporal satellite images. To characterize the morphological change during a period of twenty years, four satellite images, acquired in 1998 by Landsat TM and in 2003, 2008 and 2013 by Landsat ETM+, were classified into five main categories: Urban, Street, Soil and Vegetation. In addition, DEM has been extracted and included as Mountain. Change detection (CD) analysis is applied using post-classification comparison and GIS. As part of the study, morphological index, such as, Entropy is included for better understanding of urban structures behaviour. Mecca and its surroundings show a noticeable increase in urban and vegetation cover. Urban cover (UC) changes were divided into five radial directions: Northeast, Southeast, Southwest, East, and Northwest. These changes are influenced by mountain ranges surrounding the city and the highways. These revelations can play a significant role towards future planning and development activities, which may further promote urban growth.

  19. MAPPING THE SURROUNDINGS AS A REQUIREMENT FOR AUTONOMOUS DRIVING

    Directory of Open Access Journals (Sweden)

    M. Steininger

    2016-11-01

    Full Text Available Motivated by the hype around driverless cars and the challenges of the sensor integration and data processing, this paper presents a model for using a XBox One Microsoft Kinect stereo camera as sensor for mapping the surroundings. Today, the recognition of the environment of the car is mostly done by a mix of sensors like LiDAR, RADAR and cameras. In the case of the outdoor delivery challenge Robotour 2016 with model cars in scale 1:5, it is our goal to solve the task with one camera only. To this end, a three-stage approach was developed. The test results show that our approach can detect and locate objects at a range of up to eight meters in order to incorporate them as barriers in the navigation process.

  20. Thermodynamic stability of black holes surrounded by quintessence

    Science.gov (United States)

    Ma, Meng-Sen; Zhao, Ren; Ma, Ya-Qin

    2017-06-01

    We study the thermodynamic stabilities of uncharged and charged black holes surrounded by quintessence (BHQ) by means of effective thermodynamic quantities. When the state parameter of quintessence ω _q is appropriately chosen, the structures of BHQ are something like that of black holes in de Sitter space. Constructing the effective first law of thermodynamics in two different ways, we can derive the effective thermodynamic quantities of BHQ. Especially, these effective thermodynamic quantities also satisfy Smarr-like formulae. It is found that the uncharged BHQ is always thermodynamically unstable due to negative heat capacity, while for the charged BHQ there are phase transitions of the second order. We also show that there are several differences on the thermodynamic properties and critical behaviors of BHQ between the two ways we employed.

  1. Spirit's Surroundings on 'West Spur,' Sol 305 (3-D)

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 [figure removed for brevity, see original site] Figure 2 This 360-degree stereo panorama shows the terrain surrounding NASA's Mars Exploration Rover Spirit as of the rover's 305th martian day, or sol, (Nov. 11, 2004). At that point, Spirit was climbing the 'West Spur' of the 'Columbia Hills.' The rover had just finished inspecting a rock called 'Lutefisk' and was heading uphill toward an area called 'Machu Picchu.' Spirit used its navigational camera to take the images combined into this mosaic. The rover's location when the images were taken is catalogued as the mission's site 89, position 205. The stereo-anaglyph view presented here is a cylindrical projection with geometric seam correction. Figure 1 is the left-eye view of a stereo pair and Figure 2 is the right-eye view of a stereo pair.

  2. Progress and controversy surrounding vaccines against Lyme disease.

    Science.gov (United States)

    Hanson, Mark S; Edelman, Robert

    2003-10-01

    Less than 20 years elapsed between the 1982 report of the identification and isolation of Borrelia burgdorferi and the licensure and marketing in the USA of a prophylactic vaccine against this pathogen. However, the manufacturer removed the vaccine from the market under 4 years after its release. The low demand undoubtedly was the result of limited efficacy, need for frequent boosters, the high price of the vaccine, exclusion of children, fear of vaccine-induced musculoskeletal symptoms and litigation surrounding the vaccine. Second-generation polyvalent outer surface protein (Osp)C vaccines may overcome some of these concerns but the precise antigenic components required for efficacy are uncertain. The development of the next generation of Lyme disease vaccines is in its infancy.

  3. Controversies surrounding critical illness-related corticosteroid insufficiency in animals.

    Science.gov (United States)

    Creedon, Jamie M Burkitt

    2015-01-01

    To describe the controversies surrounding critical illness-related corticosteroid insufficiency (CIRCI) and the use of hydrocortisone in critically ill patients, and to present published diagnostic and therapeutic strategies in companion veterinary species. Critical illness-related corticosteroid insufficiency may be due to hypothalamic-pituitary-adrenal (HPA) axis dysfunction, alterations in cortisol-plasma protein binding, target cell enzymatic changes, changes in glucocorticoid receptor (GR) function, or a combination of these or other factors present during critical illness. Appropriate tests to diagnose CIRCI are unknown. The diagnosis in people is currently based on response to treatment with hydrocortisone. There is currently no consensus on appropriate diagnostic feature(s) in veterinary species. Low-dose hydrocortisone is the treatment of choice for patients with CIRCI. If the patient survives the critical illness, prognosis for resolution of CIRCI and hydrocortisone dependence is very good. © Veterinary Emergency and Critical Care Society 2014.

  4. Seismic anisotropy surrounding South China Sea and its geodynamic implications

    Science.gov (United States)

    Xue, Mei; Le, Khanh Phon; Yang, Ting

    2013-12-01

    Several mechanisms have been proposed for the opening of the South China Sea. Here, we use SKS splitting analysis to investigate the mantle flow surrounding the South China Sea. We use a total of 23 seismic stations and 87 events. We applied spectral analysis and cluster analysis to find a stable splitting solution for each event. The main conclusions are: (1) In northern Vietnam, the NW-SE fast direction is parallel to the absolute plate motion as well as GPS observations with splitting times larger than 1 s, indicating a coupled lithosphere and mantle. In contrast, in southern Vietnam, the NE-SW fast direction suggests that the lithosphere and asthenosphere are decoupled. (2) The fast directions beneath the South China Block and central Taiwan are NE-SW and NS respectively, both parallel to surface deformations with splitting times greater than 1 s, indicating that mantle flow and surface deformation are related. (3) The observed NW-SE fast directions beneath Hainan Island reflect the India-Eurasia collision, and show no signatures of an upwelling mantle plume directly underneath Hainan Island. This implies that Hainan Island is tectonically closely related to the Red River Fault, not the South China Block. (4) In Borneo, the observed NE-SW direction is parallel to the Palawan Trench, consistent with flow associated with the inactive proto-South China Sea subduction system. The SKS splitting observations surrounding South China Sea cannot be explained by a single geologic process, with either the collision-driven extrusion model or the slab pull model fitting the data presented here.

  5. Quasars Probing Quasars: the Circumgalactic Medium Surrounding z ~ 2 Quasars

    Science.gov (United States)

    Lau, Marie; Quasars Probing Quasars survey

    2018-01-01

    Understanding the circumgalactic medium--the gaseous halo surrounding a galaxy, is an integral part to understanding galaxy evolution. The z ~ 2-3 universe is interesting as this is when the star formation rate and AGN activity peak. My thesis concludes the decade-long Quasars Probing Quasars survey designed for studying massive galaxy formation and quasar feedback. I use background quasar sightlines that pass close to foreground quasars to study the circumgalactic medium of quasar-host galaxies in absorption. My sample of 149 quasar pairs involve spectra taken with 17 different optical and near IR instruments. I present results on the statistical and physical properties of the circumgalactic medium. The circumgalactic medium is enriched even beyond the virial radius. The alpha/Fe abundance ratio is enhanced, suggesting enrichment from core-collapse supernovae. The cool gas mass within the virial radius is enough to fuel star formation for another Gyr, and may account for 1/3 of the baryonic budget of the galaxy halo. The ionization state increases with projected distance from the quasar, which implies the quasar does not dominate the ionizing radiation flux. However, detection of fluorescent Lyman-alpha emission and NV absorption imply these transverse absorbers are partially illuminated by the quasar. In one peculiar case, the absorbing clump has density >100 cm^-3 and sub-parsec size. The average absorption in the circumgalactic medium exhibits large velocity widths, and is asymmetric about the systemic redshift of the galaxies. The widths are consistent with gravitational motions and Hubble flow, and outflows are not required to explain them. The asymmetry can be explained if the ionizing radiation from the quasar is anisotropic or intermittent and the gas is not in inflow. My results pose challenges for cosmological hydrodynamic simulations to produce a substantial cool gas reservoir surrounding quasars, that is also enriched and shows extreme kinematics.

  6. Axicon-based Bessel beams for flat-field illumination in total internal reflection fluorescence microscopy.

    Science.gov (United States)

    Schreiber, Benjamin; Elsayad, Kareem; Heinze, Katrin G

    2017-10-01

    Total internal reflection fluorescence microscopy (TIRF-M) provides low-invasive high-contrast surface imaging with optical sectioning of typically 100-200 nm. Thus, TIRF-M has become an established tool for imaging surfaces, including cell membranes. For TIRF-M, a homogenous evanescent field of excitation over the whole field of view is generally desired for quantitative microscopy; however, this is not necessarily straightforward to generate with Gaussian beams. In recent years, several improvements on TIRF-M have been developed that have addressed non-uniform scattering fringes and other artifacts. Here, we introduce a cost-effective TIRF setup with a very low degree of complexity and no moving parts, which provides a flattop-like excitation profile. The setup uses a tunable laser ring zoom focus system to generate a full 360° TIRF illumination. Two axicon lenses and one focus lens allow for generation and control of the ring diameter to tune the TIRF excitation angle. We show that 360° laser illumination in combination with a radial polarizer will generate an evanescent Bessel-beam excitation field that exhibits a flattop intensity over an extended part of the field of view, and demonstrate the advantages of this axicon-based Bessel beam illumination for live-cell imaging.

  7. Supersonic acoustic intensity with statistically optimized near-field acoustic holography

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn

    2011-01-01

    The concept of supersonic acoustic intensity was introduced some years ago for estimating the fraction of the flow of energy radiated by a source that propagates to the far field. It differs from the usual (active) intensity by excluding the near-field energy resulting from evanescent waves...... and circulating energy in the near-field of the source. This quantity is of concern because it makes it possible to identify the regions of a source that contribute to the far field radiation, which is often the ultimate concern in noise control. Therefore, this is a very useful analysis tool complementary...... to the information provided by the near-field acoustic holography technique. This study proposes a version of the supersonic acoustic intensity applied to statistically optimized near-field acoustic holography (SONAH). The theory, numerical results and an experimental study are presented. The possibility of using...

  8. An Index for Estimating the Stability of Brittle Surrounding Rock Mass: FAI and its Engineering Application

    Science.gov (United States)

    Zhang, C. Q.; Zhou, H.; Feng, X. T.

    2011-07-01

    Based on the geometric analysis of the relationship between the stress state at a point and the yield surface defined in the principal stress space, a coefficient ω is set up as an estimation index to describe the stress-induced yield risk. After yield, the equivalent plastic shear strains is usually used to characterize the failure degree (FD) of the material and adopted here as an index of the damage degree for the surrounding rock masses. Then, a unified variable combining ω and FD, named failure approaching index (FAI), is constructed to estimate the stability of rock mass which may be at different deformation stages. The formulas of FAI are derived for some popular yield criteria in geomechanics. Details for such development are addressed in the paper. Its rationality is verified by numerical simulation and comparative analysis of the conventional triaxial compression tests and typical tunnel projects. In addition, the method for applying FAI to the stability estimation of surrounding rock mass is proposed. As examples, the stability of the underground powerhouse, access tunnels and headrace tunnels at the Jinping II hydropower station are estimated by making use of the method we presented. The results indicate that not only is the index rational in mechanics, but the theory also has good expansibility, and the estimation methods are simple and practical as well. It is easier for field engineers to analyze and understand the numerical results.

  9. A numerical study of the nonlinear dynamics of a light, axially moving band in surrounding fluid

    Science.gov (United States)

    Koivurova, H.; Laukkanen, J.

    2009-07-01

    The vibration characteristics of a submerged axially moving band are investigated by a numerical study. A geometrically nonlinear axially moving band model is coupled to the acoustic fluid model and the periodic nonlinear problem is solved by the Fourier-Galerkin-Newton (FGN) method. The nonlinear dynamic behaviour is examined through the dependences between fundamental frequency, axial velocity and the amplitude of nonlinear free vibration. The results are compared with the behaviour of an axially moving band in a vacuum as considered in the companion paper [H. Koivurova, Journal of Sound and Vibration 320 (2009) 373-385]. In the subcritical speed range the system behaved as expected, in that the effect of the surrounding air field reduced the fundamental frequency to about one fifth of the vibration observed in a vacuum. In the supercritical speed range the effects of the surrounding air depended on the amplitude of vibration and its change with increasing geometrical nonlinearity. With linear vibrations the fundamental frequency grows faster as a function of axial velocity than in vacuum, but with nonlinear vibrations the increase in frequency is slower than in a vacuum at near-critical velocities, but with a tendency to increase faster at higher velocities.

  10. Tomography images of the Alpine roots and surrounding upper mantle

    Science.gov (United States)

    Plomerova, Jaroslava; Babuska, Vladislav

    2017-04-01

    Teleseismic body-wave tomography represents powerful tool to study regional velocity structure of the upper mantle and to image velocity anomalies, such as subducted lithosphere plates in collisional zones. In this contribution, we recapitulate 3D models of the upper mantle beneath the Alps, which developed at a collision zone of the Eurasian and African plates. Seismic tomography studies indicate a leading role of the rigid mantle lithosphere that functioned as a major stress guide during the plate collisions. Interactions of the European lithosphere with several micro-plates in the south resulted in an arcuate shape of this mountain range on the surface and in a complicated geometry of the Alpine subductions in the mantle. Early models with one bended lithosphere root have been replaced with more advanced models showing two separate lithosphere roots beneath the Western and Eastern Alps (Babuska et al., Tectonophysics 1990; Lippitsch et al., JGR 2003). The standard isotropic velocity tomography, based on pre-AlpArray data (the currently performed passive seismic experiment in the Alps and surroundings) images the south-eastward dipping curved slab of the Eurasian lithosphere in the Western Alps. On the contrary, beneath the Eastern Alps the results indicate a very steep northward dipping root that resulted from the collision of the European plate with the Adriatic microplate. Dando et al. (2011) interpret high-velocity heterogeneities at the bottom of their regional tomographic model as a graveyard of old subducted lithospheres. High density of stations, large amount of rays and dense ray-coverage of the volume studied are not the only essential pre-requisites for reliable tomography results. A compromise between the amount of pre-processed data and the high-quality of the tomography input (travel-time residuals) is of the high importance as well. For the first time, the existence of two separate roots beneath the Alps has been revealed from carefully pre

  11. Electromagnetic fields and their impacts

    Science.gov (United States)

    Prša, M. A.; Kasaš-Lažetić, K. K.

    2018-01-01

    The main goal of this paper is to briefly recall some different electromagnetic field definitions, some macroscopic sources of electromagnetic fields, electromagnetic fields classification regarding time dependences, and the ways of field determination in concrete cases. After that, all the mechanisms of interaction between electromagnetic field and substance, on atomic level, are described in details. Interaction between substance and electric field is investigated separately from the substance and magnetic field interaction. It is demonstrated that, in all cases of the unique electromagnetic field, total interaction can be treated as a superposition of two separated interactions. Finally, the main electromagnetic fields surrounding us is cited and discussed.

  12. Coastline Change Surround Sekampung River Estuary Estimated by Geographic Information System Technique

    Directory of Open Access Journals (Sweden)

    Fahri

    2011-05-01

    Full Text Available Surround a big river estuary coastline has a dynamic characteristic and change along a period of time, because of a natural process and/or it is accelerated by human activities. The surround Sekampung river estuary coastline located in Rawa Sragi area is one of the most dynamic coastlines in southern Lampung Province that has changed significantly from 1959 (as a natural process to year 1987 (as an accelerated process by human activities since the government of Indonesia has applied swamp drainage system for Rawa Sragi area. It is likely that the coastline has changed significantly in the period of 1987 to 2009 (as an increasing intensity of the human activities in the surrounding Rawa Sragi land. The objective of this research was to analyze the coastline change in the surrounding of Sekampung river estuary in two periods of time: (1 the change of the 1959 – 1987 period coastlines; and (2 the change of the 1987 – 2009 period coastlines. The method of this research was a GIS technique, the implementation was divided into three main steps: (1 the first analysis was conducted in laboratory include raster data source analysis and registration, coastline digitations, and overlaying and analysis of the coastline data; (2 field observation (ground check was conducted to observe and verify the ground existing coastline; and (3 the last analysis was conducted after ground check activity to improve and to verify the first coastline analysis results. The result of this research indicated that coastline change in the period of 1959 to 1987 increased the coast land as much as 717.19 hectares, but decreased the coast land as much as 308.51 hectares. Furthermore the coastline change in the period of 1987 to 2009 increased the coast land as much as 162.504 hectares, but decreased the coast land as much as 492.734 hectares. The 1959 – 1987 coastline change was a coast land increasing period, but the 1987 – 2009 coastline change was a coast land

  13. Transmission of ESBL/AmpC-producing Escherichia coli from broiler chicken farms to surrounding areas.

    Science.gov (United States)

    Laube, H; Friese, A; von Salviati, C; Guerra, B; Rösler, U

    2014-08-27

    Although previous studies have demonstrated high carriage of ESBL/AmpC-producing Escherichia coli in livestock, especially in broiler chickens, data on emission sources of these bacteria into the environment are still rare. Therefore, this study was designed to systematically investigate the occurrence of ESBL/AmpC-producing E. coli in slurry, air (inside animal houses), ambient air (outside animal houses) and on soil surfaces in the areas surrounding of seven ESBL/AmpC-positive broiler chicken fattening farms, including investigation of the possible spread of these bacteria via the faecal route and/or exhaust air into the environment. Seven German broiler fattening farms were each investigated at three points in time (3-36 h after restocking, 14-18 and 26-35 days after housing) during one fattening period. The occurrence of ESBL/AmpC genes in the investigated samples was confirmed by PCR, detecting blaCTX-M, blaSHV, blaTEM and blaCMY-genes, and, if necessary, by sequencing and/or the disc diffusion method. The results showed a wide spread of ESBL/AmpC-producing E. coli in broiler farms, as well as emissions into the surroundings. 12 out of 14 (86%) slurry samples were positive for ESBL/AmpC-producing E. coli. Additionally, 28.8% (n=23/80) of boot swabs taken from various surfaces in the areas surrounding of the farms as well as 7.5% (n=3/40) of the exhaust air samples turned out to be positive for these microorganisms. Moreover, a small proportion of air samples from inside the barns were ESBL/AmpC-positive. By comparing selected isolates using pulsed field gel electrophoresis, we proved that faecal and airborne transfer of ESBL/AmpC-producing microorganisms from broiler fattening farms to the surrounding areas is possible. Two isolates from farm G2 (slurry and boot swab 50 m downwind), two isolates from farm G3 (slurry and individual animal swab) as well as two isolates from farm G6 (air sample in the barn and air sample 50 m downwind) showed 100% similarity in

  14. Fluid Production Induced Stress Analysis Surrounding an Elliptic Fracture

    Science.gov (United States)

    Pandit, Harshad Rajendra

    Hydraulic fracturing is an effective technique used in well stimulation to increase petroleum well production. A combination of multi-stage hydraulic fracturing and horizontal drilling has led to the recent boom in shale gas production which has changed the energy landscape of North America. During the fracking process, highly pressurized mixture of water and proppants (sand and chemicals) is injected into to a crack, which fractures the surrounding rock structure and proppants help in keeping the fracture open. Over a longer period, however, these fractures tend to close due to the difference between the compressive stress exerted by the reservoir on the fracture and the fluid pressure inside the fracture. During production, fluid pressure inside the fracture is reduced further which can accelerate the closure of a fracture. In this thesis, we study the stress distribution around a hydraulic fracture caused by fluid production. It is shown that fluid flow can induce a very high hoop stress near the fracture tip. As the pressure gradient increases stress concentration increases. If a fracture is very thin, the flow induced stress along the fracture decreases, but the stress concentration at the fracture tip increases and become unbounded for an infinitely thin fracture. The result from the present study can be used for studying the fracture closure problem, and ultimately this in turn can lead to the development of better proppants so that prolific well production can be sustained for a long period of time.

  15. Beliefs and practices surrounding postpartum period among Myanmar women.

    Science.gov (United States)

    Sein, Kyi Kyi

    2013-11-01

    to examine the postpartum beliefs and practices among young women (15-24 years) both quantitative and qualitative approaches were used: a cross-sectional comparative study using a semi-structured questionnaire and focus group discussions (FGDs). Kyimyindaing Township in the western district of Yangon, Myanmar. young women (15-24 years) who had experience of at least one live birth were included. A total of 196 women for a quantitative survey and 31 women for FGDs were recruited. postpartum beliefs and practices at the last childbirth were explored by a pretested semi-structured questionnaire and four FGDs (two in urban and two in rural areas). The survey questionnaire covered socio-demographic data, food and behavioural restrictions and observances during the last postpartum period and underlying reasons for those practices. Majority of participants followed the traditional postpartum practices regardless of the area of residence and education level. Notion of 'dirty lochia' was identified. traditional beliefs and practices surrounding post partum were highly prevalent among young women. Variation in degree and duration of adherence to postpartum taboos was noted. These beliefs and practices were imparted and perpetuated by women's close social network. the findings point out the importance of awareness of postpartum beliefs and practices among health staff for providing culturally sensitive health care and gaining better co-operation and mutual understanding in giving health care. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Preliminary Analysis of Slope Stability in Kuok and Surrounding Areas

    Directory of Open Access Journals (Sweden)

    Dewandra Bagus Eka Putra

    2016-12-01

    Full Text Available The level of slope influenced by the condition of the rocks beneath the surface. On high level of slopes, amount of surface runoff and water transport energy is also enlarged. This caused by greater gravity, in line with the surface tilt from the horizontal plane. In other words, topsoil eroded more and more. When the slope becomes twice as steep, then the amount of erosion per unit area be 2.0 - 2.5 times more. Kuok and surrounding area is the road access between the West Sumatra and Riau which plays an important role economies of both provinces. The purpose of this study is to map the locations that have fairly steep slopes and potential mode of landslides. Based on SRTM data obtained,  the roads in Kuok area has a minimum elevation of + 33 m and a maximum  + 217.329 m. Rugged road conditions with slope ranging from 24.08 ° to 44.68 ° causing this area having frequent landslides. The result of slope stability analysis in a slope near the Water Power Plant Koto Panjang, indicated that mode of active failure is toppling failure or rock fall and the potential zone of failure is in the center part of the slope.

  17. Tuning structure and mobility of solvation shells surrounding tracer additives.

    Science.gov (United States)

    Carmer, James; Jain, Avni; Bollinger, Jonathan A; van Swol, Frank; Truskett, Thomas M

    2015-03-28

    Molecular dynamics simulations and a stochastic Fokker-Planck equation based approach are used to illuminate how position-dependent solvent mobility near one or more tracer particle(s) is affected when tracer-solvent interactions are rationally modified to affect corresponding solvation structure. For tracers in a dense hard-sphere fluid, we compare two types of tracer-solvent interactions: (1) a hard-sphere-like interaction, and (2) a soft repulsion extending beyond the hard core designed via statistical mechanical theory to enhance tracer mobility at infinite dilution by suppressing coordination-shell structure [Carmer et al., Soft Matter 8, 4083-4089 (2012)]. For the latter case, we show that the mobility of surrounding solvent particles is also increased by addition of the soft repulsive interaction, which helps to rationalize the mechanism underlying the tracer's enhanced diffusivity. However, if multiple tracer surfaces are in closer proximity (as at higher tracer concentrations), similar interactions that disrupt local solvation structure instead suppress the position-dependent solvent dynamics.

  18. Mercury's interior, surface, and surrounding environment latest discoveries

    CERN Document Server

    Clark, Pamela Elizabeth

    2015-01-01

    This SpringerBrief details the MESSENGER Mission, the findings of which present challenges to widely held conventional views and remaining mysteries surrounding the planet. The work answers the question of why Mercury is so dense, and the implications from geochemical data on its planetary formation. It summarizes imaging and compositional data from the terrestrial planet surface processes and explains the geologic history of Mercury.  It also discusses the lack of southern hemisphere coverage. Our understanding of the planet Mercury has been in a transitional phase over the decades since Mariner 10. The influx of new data from the NASA MESSENGER Mission since it was inserted into the orbit of Mercury in March of 2011 has greatly accelerated that shift. The combined compositional data of relatively high volatiles (S, K), relatively low refractories (Al, Ca), and low crustal iron, combined with an active, partially molten iron rich core, has major implications for Mercury and Solar System formation. From a s...

  19. Dilemmas surrounding passive euthanasia--a Malaysian perspective.

    Science.gov (United States)

    Talib, Norchaya

    2005-09-01

    In western societies where the principle of autonomy is jealously guarded, perhaps active euthanasia is more often the focus of public concern and debates rather than any other forms of euthanasia. However due to the advance in technology and its corresponding ability in prolonging life, in Malaysia passive euthanasia presents more of a dilemma. For those concerned and involved with end of life decision-making, it is generally agreed that this is an area fraught with not only medical but legal and ethical issues. In Malaysia where the society is not homogenous but is multi-cultural and multi-religious, in addition to medical, legal and ethical issues, religious principles and cultural norms further impact and play significant roles in end of life decision-making. This paper seeks to identify the issues surrounding the practice of passive euthanasia in Malaysia. It will be shown that despite applicable legal provisions, current practice of the medical profession combined with religious and cultural values together affect decision-making which involves the withholding and/or withdrawing of life-saving treatment.

  20. Democratizing rendering for multiple viewers in surround VR systems

    KAUST Repository

    Schulze, Jürgen P.

    2012-03-01

    We present a new approach for how multiple users\\' views can be rendered in a surround virtual environment without using special multi-view hardware. It is based on the idea that different parts of the screen are often viewed by different users, so that they can be rendered from their own view point, or at least from a point closer to their view point than traditionally expected. The vast majority of 3D virtual reality systems are designed for one head-tracked user, and a number of passive viewers. Only the head tracked user gets to see the correct view of the scene, everybody else sees a distorted image. We reduce this problem by algorithmically democratizing the rendering view point among all tracked users. Researchers have proposed solutions for multiple tracked users, but most of them require major changes to the display hardware of the VR system, such as additional projectors or custom VR glasses. Our approach does not require additional hardware, except the ability to track each participating user. We propose three versions of our multi-viewer algorithm. Each of them balances image distortion and frame rate in different ways, making them more or less suitable for certain application scenarios. Our most sophisticated algorithm renders each pixel from its own, optimized camera perspective, which depends on all tracked users\\' head positions and orientations. © 2012 IEEE.

  1. Issues surrounding lethal injection as a means of capital punishment.

    Science.gov (United States)

    Romanelli, Frank; Whisman, Tyler; Fink, Joseph L

    2008-12-01

    Lethal injection as a method of state-sanctioned capital punishment was initially proposed in the United States in 1977 and used for the first time in 1982. Most lethal injection protocols use a sequential drug combination of sodium thiopental, pancuronium bromide, and potassium chloride. Lethal injection was originally introduced as a more humane form of execution compared with existing mechanical methods such as electrocution, toxic gassing, hanging, or firing squad. Lethal injection has not, however, been without controversy. Several states are considering whether lethal injection meets constitutional scrutiny forbidding cruel and unusual punishment. Recently in the case of Ralph Baze and Thomas C. Bowling, Petitioners, v John D. Rees, Commissioner, Kentucky Department of Corrections et al, the United States Supreme Court upheld the constitutionality of the lethal injection protocol as carried out in the Commonwealth of Kentucky. Most of the debate has surrounded the dosing and procedures used in lethal injection and whether the drug combinations and measures for administering the drugs truly produce a timely, pain-free, and fail-safe death. Many have also raised issues regarding the "medicalization" of execution and the ethics of health care professionals' participation in any part of the lethal injection process. As a result of all these issues, the future of lethal injection as a means of execution in the United States is under significant scrutiny. Outcomes of ongoing legislative and judicial reviews might result in cessation of lethal injection in totality or in alterations involving specific drug combinations or administration procedures.

  2. A composite mineralogical map of Ganges Chasma and surroundings, Valles Marineris, Mars

    Science.gov (United States)

    Cull-Hearth, Selby; Clark, M. Caroline

    2017-08-01

    Ganges Chasma is a mineralogically diverse canyon in the far-eastern portion of the Valles Marineris system. It exposes bedrock outcrops of olivine, large dune fields enriched in olivine, a central Interior Layered Deposit with monohydrated sulfates, and Fe/Mg-phyllosilicates on the plateaus surrounding the canyon and in the canyon walls. The co-existence of hydrated minerals with unaltered olivine makes this an excellent location to study the timing of aqueous processes in this region. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and the High-Resolution Imaging Science Experiment (HiRISE), synthesizing them with previous data sets to produce a composite mineralogical map of Ganges Chasma. We then produce a timeline of mineralogic deposition for the Ganges area, relating it to regional geologic events.

  3. NATURAL VALUES OF THE VEGETATION OF SPRINGS IN USTROŃ SURROUNDINGS AND ITS IMPORTANCE TO ECOTOURISM

    Directory of Open Access Journals (Sweden)

    Zbigniew Wilczek

    2014-11-01

    Full Text Available Ustroń is a spa town in Southern Poland in area of the Western Carpathians (attitude range: 360–480 m a.s.l.. It is very popular with tourists due to its proximity to biggest urban area of Poland – Upper Silesian Metropolis (about 50 km. The objects of study were surroundings of 3 popular mineral springs in Ustroń: Karol Spring, Ferruginous Spring and Spring on Równica Hill. Field research concerned vegetation and florawithin 100 m of each spring. Results show occurrence of 21 different vegetation types from 8 vegetation classes and 167 vascular species. Many of them are rare and legal protected. Natural values of study area could be use in promotion of ecotourism in Ustroń. What more, each plant community have specific influence to a human health and local bioclimatic properties, so it is necessary to recognize vegetation of spa towns.

  4. Compact Modeling of Qunatum Effects in Undoped Long- Channel Cylindrical Surrounding-Gate MOSFETs

    Science.gov (United States)

    Bimo, Christoforus; Noor, Fatimah A.; Khairurrijal

    2016-08-01

    Quantum effects have been incorporated in the analytic potential model for cylindrical surrounding-gate or gate-all-around metal oxide semiconductor field effect transistors (MOSFETs). By extracting some constants parameter from the self-consistent Schrodinger and Poisson equations, two physical parameters, threshold voltage shift and inversion layer centroid, are expressed as closed form function of device radius and charge density. The quantum version of inversion charge density is obtained by incorporating of those parameters into the classical procedure as modifications for gate work function and inversion layer capacitance. The model represented here has been able to reproduce simulation data obtained from self-consistent calculation. The calculated results show that the model fits well with the self-consistent calculation.

  5. The properties of surround antagonism elicited by spinning windmill patterns in the mudpuppy retina.

    Science.gov (United States)

    Thibos, L N; Werblin, F S

    1978-05-01

    1. A truncated spinning windmill pattern, illuminating only the receptive field surround, shown previously to activate amacrine cells, was used to elicit activity at the inner plexiform layer and to reduce the response of ganglion cells to test flashes at the receptive field centre. 2. The spinning windmill pattern reduced the ganglion cell response over its entire graded range by a fixed amount, and reduced the domain of test intensities required for graded activity. 3. The windmill effect was graded for windmill intensities over a domain of about 1000 to 1. The effect was constant for windmill velocities from about 0.05 to 0.5 rev/sec, and diminished beyond these velocities. 4. The windmill effect varied with windmill area as though each retinal point contributed to the reduction of ganglion cell response with a weighting which fell exponentially from the receptive field centre. The space constant was 0.35 mm. 5. The graded reduction in ganglion cell response was closely correlated with the graded increase in amacrine cell activity when the windmill intensity, area, and velocity were varied. It is inferred that amacrine cells, activated by the windmill, act to reduce the response range of the ganglion cells, primarily through a feed-forward pathway.

  6. Morphological Segregation in the Surroundings of Cosmic Voids

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardelli, Elena; Tamone, Amelie [Laboratoire d’Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), 1290 Sauverny (Switzerland); Cava, Antonio [Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Versoix (Switzerland); Varela, Jesus, E-mail: elena.ricciardelli@epfl.ch [Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza San Juan 1, E-44001 Teruel (Spain)

    2017-09-01

    We explore the morphology of galaxies living in the proximity of cosmic voids, using a sample of voids identified in the Sloan Digital Sky Survey Data Release 7. At all stellar masses, void galaxies exhibit morphologies of a later type than galaxies in a control sample, which represent galaxies in an average density environment. We interpret this trend as a pure environmental effect, independent of the mass bias, due to a slower galaxy build-up in the rarefied regions of voids. We confirm previous findings about a clear segregation in galaxy morphology, with galaxies of a later type being found at smaller void-centric distances with respect to the early-type galaxies. We also show, for the first time, that the radius of the void has an impact on the evolutionary history of the galaxies that live within it or in its surroundings. In fact, an enhanced fraction of late-type galaxies is found in the proximity of voids larger than the median void radius. Likewise, an excess of early-type galaxies is observed within or around voids of a smaller size. A significant difference in galaxy properties in voids of different sizes is observed up to 2 R {sub void}, which we define as the region of influence of voids. The significance of this difference is greater than 3 σ for all the volume-complete samples considered here. The fraction of star-forming galaxies shows the same behavior as the late-type galaxies, but no significant difference in stellar mass is observed in the proximity of voids of different sizes.

  7. Morphological Segregation in the Surroundings of Cosmic Voids

    Science.gov (United States)

    Ricciardelli, Elena; Cava, Antonio; Varela, Jesus; Tamone, Amelie

    2017-09-01

    We explore the morphology of galaxies living in the proximity of cosmic voids, using a sample of voids identified in the Sloan Digital Sky Survey Data Release 7. At all stellar masses, void galaxies exhibit morphologies of a later type than galaxies in a control sample, which represent galaxies in an average density environment. We interpret this trend as a pure environmental effect, independent of the mass bias, due to a slower galaxy build-up in the rarefied regions of voids. We confirm previous findings about a clear segregation in galaxy morphology, with galaxies of a later type being found at smaller void-centric distances with respect to the early-type galaxies. We also show, for the first time, that the radius of the void has an impact on the evolutionary history of the galaxies that live within it or in its surroundings. In fact, an enhanced fraction of late-type galaxies is found in the proximity of voids larger than the median void radius. Likewise, an excess of early-type galaxies is observed within or around voids of a smaller size. A significant difference in galaxy properties in voids of different sizes is observed up to 2 R void, which we define as the region of influence of voids. The significance of this difference is greater than 3σ for all the volume-complete samples considered here. The fraction of star-forming galaxies shows the same behavior as the late-type galaxies, but no significant difference in stellar mass is observed in the proximity of voids of different sizes.

  8. GIANT Hα NEBULA SURROUNDING THE STARBURST MERGER NGC 6240

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Michitoshi [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Yagi, Masafumi; Komiyama, Yutaka; Kashikawa, Nobunari [Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Ohyama, Youichi [Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, AS/NTU No.1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan, R.O.C. (China); Tanaka, Hisashi [Department of Physical Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Okamura, Sadanori, E-mail: yoshidam@hiroshima-u.ac.jp [Department of Advanced Sciences, Faculty of Science and Engineering, Hosei University, Koganei, Tokyo 184-8584 (Japan)

    2016-03-20

    We revealed the detailed structure of a vastly extended Hα-emitting nebula (“Hα nebula”) surrounding the starburst/merging galaxy NGC 6240 by deep narrow-band imaging observations with the Subaru Suprime-Cam. The extent of the nebula is ∼90 kpc in diameter and the total Hα luminosity amounts to L{sub Hα} ≈ 1.6 × 10{sup 42} erg s{sup −1}. The volume filling factor and the mass of the warm ionized gas are ∼10{sup −4}–10{sup −5} and ∼5 × 10{sup 8} M{sub ⊙}, respectively. The nebula has a complicated structure, which includes numerous filaments, loops, bubbles, and knots. We found that there is a tight spatial correlation between the Hα nebula and the extended soft-X-ray-emitting gas, both in large and small scales. The overall morphology of the nebula is dominated by filamentary structures radially extending from the center of the galaxy. A large-scale bipolar bubble extends along the minor axis of the main stellar disk. The morphology strongly suggests that the nebula was formed by intense outflows—superwinds—driven by starbursts. We also found three bright knots embedded in a looped filament of ionized gas that show head-tail morphologies in both emission-line and continuum, suggesting close interactions between the outflows and star-forming regions. Based on the morphology and surface brightness distribution of the Hα nebula, we propose the scenario that three major episodes of starburst/superwind activities, which were initiated ∼10{sup 2} Myr ago, formed the extended ionized gas nebula of NGC 6240.

  9. Behavioural aspects surrounding medicine purchases from pharmacies in Australia

    Directory of Open Access Journals (Sweden)

    Emmerton L

    2008-09-01

    Full Text Available Objective: This study aimed to produce current data regarding behavioural aspects of non-prescription (over-the-counter medicine purchases, in light of changes in the pharmaceutical market and increasing provision of professional services in pharmacies.Methods: Data were collected in 15 community pharmacies in South-East Queensland, Australia, over 540 hours in five days in August, 2006. The method, previously validated, involved documentation of both observational and interview data. Fifteen trained researchers were stationed in a selected pharmacy each to unobtrusively observe all eligible sales of non-prescription medicines, and, where possible, interview the purchasers post-sale. Non-response was supplemented by observational data and recall by the salesperson. The data included details of the purchase and purchasing behaviour, while new questions addressed issues of topical importance, including customers’ privacy concerns. A selection of the analyses is reported here.Results: In total, 3470 purchases were documented (135-479 per pharmacy, with customers of 67.5% of purchases (74.7% excluding an outlier pharmacy participating in the survey. Customers averaged 1.2 non-prescription medicines per transaction. Two-thirds (67.2% of customers were female, and 38.8% of the customers were aged 31-45 years. Analgesics and respiratory medicines accounted for two-thirds of the sales data (33.4% and 32.4%, respectively. Intended-brand purchases comprised 71% of purchases (2004/2824; in-store substitution then occurred in 8.8% of these cases, mainly following recommendations by pharmacy staff. Medicines intended for self-use comprised 62.9% of purchases (1752/2785. First-time purchases (30.8%, 799/2594 were more commonly influenced by pharmacy staff than by advertising.Conclusions: This study used validated methods adapted to a changing marketplace, thus providing data that both confirm and add to knowledge surrounding medicine purchases. Despite the

  10. Circumstances surrounding dying in the paediatric intensive care unit

    Directory of Open Access Journals (Sweden)

    Plötz Frans B

    2006-08-01

    Full Text Available Abstract Background Death is inevitable in the paediatric intensive care unit (PICU. We aimed to describe the circumstances surrounding dying in a PICU. Method The chart records of all patients less than 18 years of age who died at the PICU between January first 2000 and July first 2005 were retrospectively analyzed. Information regarding sex, age, length of stay, admission, diagnosis, and the way a patient died was registered. Post mortem information regarding natural versus unnatural death, autopsy and donation was obtained. Non-survivors were allocated in five groups: do-not-resuscitate (DNR, withholding and/or withdrawal of therapy (W/W, failed cardiopulmonary resuscitation (failed CPR, brain death (BD, and terminal organ failure (TOF. Results During the study period 87 (4.4% of the 1995 admitted patients died. Non-survivors were more often admitted during the day (54% and the week (68%. W/W was found in 27.6%, TOF in 26.4%, BD in 23.0%, failed CPR in 18.4%, and DNR in 4.6%. Forty-three percent died in the first two days, of which BD (40.5% and failed CPR (37.8% were most common. Seventy-five children (86% died due to a natural cause. Autopsy permission was obtained in 19 of 54 patients (35%. The autopsies confirmed the clinical diagnosis in 11 patients, revealed new information in 5 patients, and in 3 patients the autopsy did not provide additional information. Nine patients were medically suitable for organ donation and 24 patients for tissue donation, whereas consent was only obtained in 2 cases in both groups. Conclusion We observed that 43% of the patients died within the first two days of admission due to BD and failed CPR, whereas after 4 days most patients died after W/W. Autopsy remains an useful tool to confirm clinical diagnoses or to provide new information. Only a small percentage of the deceased children is suitable for organ donation.

  11. Chandra Uncovers New Evidence For Event Horizons Surrounding Black Holes

    Science.gov (United States)

    2001-01-01

    SAN DIEGO -- Astronomers have used NASA's Chandra X-ray Observatory to study some of the darkest black holes yet observed. Their work strongly confirms the reality of the "event horizon," the one-way membrane around black holes predicted by Einstein's theory of relativity. The findings were presented today at the American Astronomical Society meeting by Drs. Michael Garcia, Jeffrey McClintock, Ramesh Narayan, and Stephen Murray of the Harvard-Smithsonian Center for Astrophysics and Dr. Paul Callanan of University College, Cork, Ireland. With results that fundamentally differ from earlier black hole studies, Garcia and his colleagues have shown that some recently discovered black holes are not only ultra-dense, but actually possess event horizons that "vacuum up" energy from their surroundings. "It is a bit odd to say we've discovered something by seeing almost nothing at all -- less than the smile of the Cheshire cat, so to speak," said Garcia, lead author on a paper submitted to the Astrophysical Journal, "but, in essence, this is what we have done." Using data from Chandra and previous X-ray satellites like ROSAT, the Chandra team studied a dozen "X-ray novas," so named because they occasionally erupt as brilliant X-ray sources then settle into decades of dormancy. The great outpouring of X rays is due to a stream of gas that is pulled from the surface of a Sun-like companion star onto a compact object, either a black hole or a neutron star. By comparing the energy output from the dormant X-ray novas, the team discovered that the sources with black holes emitted only one percent as much energy while dormant as did the X-ray novae with neutron stars. "The most straightforward explanation of these observations is that the black hole candidates we have studied have event horizons that swallow just about all of the energy that surrounds them," said Murray. "Indeed, one could even say that this work shows why black holes deserve to be called ‘black.’" "The event

  12. Magnetic map of the Irish Hills and surrounding areas, San Luis Obispo County, central California

    Science.gov (United States)

    Langenheim, V.E.; Watt, J.T.; Denton, K.M.

    2012-01-01

    A magnetic map of the Irish Hills and surrounding areas was created as part of a cooperative research and development agreement with the Pacific Gas and Electric Company and is intended to promote further understanding of the areal geology and structure by serving as a basis for geophysical interpretations and by supporting geological mapping, mineral and water resource investigations, and other topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on magnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals can be related to either lithologic or structural boundaries. Magnetic susceptibility measurements from the area indicate that bodies of serpentinite and other mafic and ultramafic rocks tend to produce the most intense magnetic anomalies, but such generalizations must be applied with caution because some sedimentary units also can produce measurable magnetic anomalies. Remanent magnetization does not appear to be a significant source for magnetic anomalies because it is an order of magnitude less than the induced magnetization. The map is a mosaic of three separate surveys collected by (1) fixed-wing aircraft at a nominal height of 305 m, (2) by boat with the sensor at sea level, and (3) by helicopter. The helicopter survey was flown by New-Sense Geophysics in October 2009 along flight lines spaced 150-m apart and at a nominal terrain clearance of 50 to 100 m. Tie lines were flown 1,500-m apart. Data were adjusted for lag error and diurnal field variations. Further processing included microleveling using the tie lines and subtraction of the reference field defined by International Geomagnetic Reference Field (IGRF) 2005 extrapolated to August 1, 2008.

  13. Robust computation of dipole electromagnetic fields in arbitrarily anisotropic, planar-stratified environments.

    Science.gov (United States)

    Sainath, Kamalesh; Teixeira, Fernando L; Donderici, Burkay

    2014-01-01

    We develop a general-purpose formulation, based on two-dimensional spectral integrals, for computing electromagnetic fields produced by arbitrarily oriented dipoles in planar-stratified environments, where each layer may exhibit arbitrary and independent anisotropy in both its (complex) permittivity and permeability tensors. Among the salient features of our formulation are (i) computation of eigenmodes (characteristic plane waves) supported in arbitrarily anisotropic media in a numerically robust fashion, (ii) implementation of an hp-adaptive refinement for the numerical integration to evaluate the radiation and weakly evanescent spectra contributions, and (iii) development of an adaptive extension of an integral convergence acceleration technique to compute the strongly evanescent spectrum contribution. While other semianalytic techniques exist to solve this problem, none have full applicability to media exhibiting arbitrary double anisotropies in each layer, where one must account for the whole range of possible phenomena (e.g., mode coupling at interfaces and nonreciprocal mode propagation). Brute-force numerical methods can tackle this problem but only at a much higher computational cost. The present formulation provides an efficient and robust technique for field computation in arbitrary planar-stratified environments. We demonstrate the formulation for a number of problems related to geophysical exploration.

  14. Electromagnetic scattering of a polarized plane wave from an ellipsoidal particle in the near field

    Science.gov (United States)

    Chen, Feinan; Li, Jia

    2017-06-01

    Within the validity of the first-order Born approximation, we study the near-zone evanescent wave properties for a polarized plane wave scattering upon an ellipsoidal particle. Integral expressions are obtained for the three-dimensional electromagnetic field of the near-zone scattered evanescent wave, and the dependences of the scattered intensity distributions on the degree of polarization of the incident wave and the scattering potential profile of the particle are presented. The scattered intensity from the particle can exhibit a focused pattern concentrated around the central scattering region, but the scattered intensity generated from a circularly polarized wave shows a smooth distribution for different scattering angles. Moreover, the scattered intensity also enhances when either the summation index or the effective radius of the particle increases. Our results can be utilized to generate near-field focused scattered patterns that can be tuned flexibly by controlling the degree of the polarization of the plane wave and the scattering potential parameters of the ellipsoidal particle.

  15. Investigation of roadside fine particulate matter concentration surrounding major arterials in five Southern Californian cities.

    Science.gov (United States)

    Pan, Hansheng; Bartolome, Christian; Gutierrez, Eric; Princevac, Marko; Edwards, Rufus; Boarnet, Marlon G; Houston, Douglas

    2013-04-01

    The built environment surrounding arterials affects the dispersion of vehicular emissions in urban areas, modifying the potential risks to public health. In order to study the influence of urban morphometry on flow and dispersion of vehicular fine particulate matter emissions, in the summer of 2008 field measurements were performed in major arterials located in five Southern Californian cities with different building geometries. In each city, local mean wind, turbulence, virtual temperature, roadside DustTrak Fine Particles (DTFP) concentration, and traffic flow data were collected in 2-hr measurement periods during morning and evening rush hours and lighter midday traffic, over a period of 3 days. The calculated Monin-Obukhov length, L, suggests that near-neutral and slightly unstable conditions were present at both street and roof levels. The nondimensional forms of turbulent wind and temperature fluctuations show,that the data at street level within the urban canopy can be represented using the Monin-Obukhov similarity theory. Generalized additive models were applied to analyze the impact of meteorological and traffic-related variables on fine particle concentrations at street level Compared to other variables, urban-scale background concentrations were the most important variables in all five models. The results confirmed that turbulent mixing in urban areas dominated the variation of roadside particle concentrations regardless of urban geometry. The distance from the local sites to the nearby monitoring stations affected model performance when urban-scale concentrations were used to predict middle-scale concentrations by generalized additive models (GAMs). A radius ofinfluence for background concentrations was 6-10 km. There were also relationships between concentration and other variables affecting the local components of the concentrations, such as wind direction, sensible heat flux, and vertical wind fluctuation, although the influences were much weaker

  16. Effectiveness of vegetation buffers surrounding playa wetlands at contaminant and sediment amelioration.

    Science.gov (United States)

    Haukos, David A; Johnson, Lacrecia A; Smith, Loren M; McMurry, Scott T

    2016-10-01

    Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30-60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands. Published by Elsevier Ltd.

  17. Submillimetre observations of WISE-selected high-redshift, luminous AGN and their surrounding overdense environments

    Science.gov (United States)

    Jones, Suzy F.

    2016-08-01

    We present JCMT SCUBA-2 850 μm submillimetre (submm) observations of 10 mid-infrared (mid-IR) luminous active galactic nuclei (AGNs), detected by the Wide-field Infrared Survey Explorer (WISE) all-sky IR survey and 30 that have also been detected by the NVSS/FIRST radio survey. These rare sources are selected by their extremely red mid-IR spectral energy distributions (SEDs). Further investigations show that they are highly obscured, have abundant warm AGN-heated dust and are thought to be experiencing intense AGN feedback. When comparing the number of submm galaxies detected serendipitously in the surrounding 1.5 arcmin to those in blank-field submm surveys, there is a very significant overdensity, of order 3-5, but no sign of radial clustering centred at our primary objects. The WISE-selected AGN thus reside in 10-Mpc-scale overdense environments that could be forming in pre-viralized clusters of galaxies. WISE-selected AGNs appear to be the strongest signposts of high-density regions of active, luminous and dusty galaxies. SCUBA-2 850 μm observations indicate that their submm fluxes are low compared to many popular AGN SED templates, hence the WISE/radio-selected AGNs have either less cold and/or more warm dust emission than normally assumed for typical AGN. Most of the targets have total IR luminosities ≥1013 L⊙, with known redshifts of 20 targets between z ˜ 0.44-4.6.

  18. P3-23: Center/Surround Motion Interactions Measured Using a Nulling Procedure

    Directory of Open Access Journals (Sweden)

    Soo Hyun Park

    2012-10-01

    Full Text Available Many direction-selective neurons have a receptive field structure that promotes suppressive interactions between center and surround regions. These interactions sculpt the overall pattern of activity among those neurons and, therefore, presumably impact perceived direction of motion. To test this conjecture, we have assessed the effect of motion signals produced by a moving stimulus on perceived motion within a neighboring region. On each trial a vertical bar (inducer appeared at 8 eccentricity in the upper visual field, moving either leftward or rightward, and a circular shaped random dot kinematogram (test appeared at 4 eccentricity. The test dots moved randomly except when the inducer passed nearby the test, at which time a pulse of coherent motion occurred in one of the two directions within the test. Coherence strength was adjusted by QUEST to maintain equal likelihood (point of subjective equality: PSE of leftward and rightward reports of perceived direction during this motion pulse. The inducer caused a substantial shift in PSE: it was necessary for the test to contain 50% coherent motion in the same direction as that of the inducer to nullify the illusory motion within the test caused by the inducer. The effect of the inducer could also be offset by simultaneously presenting a second inducer moving in the opposite direction. This pattern of results implies substantial suppressive interactions between neighboring moving stimuli, interactions whose strength and direction can be assessed psychophysically using nulling procedures.

  19. Thermal conditions for geothermal energy exploitation in the Transcarpathian depression and surrounding units

    Science.gov (United States)

    Majcin, Dušan; Kutas, Roman; Bilčík, Dušan; Bezák, Vladimír; Korchagin, Ignat

    2016-03-01

    The contribution presents the results acquired both by direct cognitive geothermic methods and by modelling approaches of the lithosphere thermal state in the region of the Transcarpathian depression and surrounding units. The activities were aimed at the determination of the temperature field distribution and heat flow density distribution in the upper parts of the Earth's crust within the studied area. Primary new terrestrial heat flow density map was constructed from values determined for boreholes, from their interpretations and from newest outcomes of geothermal modelling methods based on steady-state and transient approaches, and also from other recently gained geophysical and geological knowledge. Thereafter we constructed the maps of temperature field distribution for selected depth levels of up to 5000 m below the surface. For the construction we have used measured borehole temperature data, the interpolation and extrapolation methods, and the modelling results of the refraction effects and of the influences of source type anomalies. New maps and other geothermic data served for the determination of depths with rock temperatures suitable for energy utilization namely production of electric energy minimally by the binary cycles. Consequently the thermal conditions were used to identify the most perspective areas for geothermal energy exploitation in the region under study.

  20. Near field optical and spectroscopic imaging of InN nanostructures

    Science.gov (United States)

    Madapu, Kishore K.; Sivadasan, A. K.; Dhara, Sandip

    2017-05-01

    Conventional optical spectroscopy is limited by the diffraction limit which impose the condition of spatial resolution to be achieved ≤ λ/2. Near field optical microscopic techniques such as near field scanning optical microscopy (NSOM) and tip enhanced Raman spectroscopy (TERS) improves the spatial resolution by utilizing the evanescent field. Here, we studied the near field light matter interaction of InN nanostructures using the NSOM technique and achieved a spatial resolution of 50 nm with 150 nm aperture tip and 532 nm light source. The optical contrast in the NSOM images is attributed to the local variation of dielectric constant of individual nanostructures. TERS imaging is performed with an atomic force microscopy (AFM) tip attached with a 300 nm Au particle to achieve a sub-diffraction spatial resolution of ˜200 nm using 785 nm laser excitation.

  1. Feedback inhibition in the inner plexiform layer underlies the surround-mediated responses of AII amacrine cells in the mammalian retina.

    Science.gov (United States)

    Völgyi, Béla; Xin, Daiyan; Bloomfield, Stewart A

    2002-03-01

    Intracellular recordings were made from narrow-field, bistratified AII amacrine cells in the isolated, superfused retina-eyecup of the rabbit. Pharmacological agents were applied to neurons to dissect the synaptic pathways subserving AII cells so as to determine the circuitry generating their off-surround responses. Application of the GABA antagonists, picrotoxin, bicuculline and 1,2,5,6-tetrahydropyridine-4-yl methylphosphinic acid (TPMPA) all increased the on-centre responses of AII amacrine cells, but attenuated the off-surround activity. At equal concentrations, picrotoxin was approximately twice as effective as bicuculline or TPMPA in modifying the response activity of AII amacrine cells. These results indicate that the mechanism underlying surround inhibition of AII amacrine cells includes activation of both GABA(A) and GABA(C) receptors in an approximately equal ratio. Application of the GABA antagonists also increased the size of on-centre receptive fields of AII amacrine cells. Again, picrotoxin was most effective, producing, on average, a 54 % increase in the size of the receptive field, whereas bicuculline and TPMPA produced comparable 34 and 33 % increases, respectfully. Application of the voltage-gated sodium channel blocker TTX produced effects on AII amacrine cells qualitatively similar to those of the GABA blockers. Intracellular application of the chloride channel blocker 4,4'-dinitro-stilbene-2,2'-disulphonic acid (DNDS) abolished the direct effects of GABA on AII amacrine cells. Moreover, DNDS increased the amplitude of both the on-centre and off-surround responses. The failure of DNDS to block the off-surround activity indicates that it is not mediated by direct GABAergic inhibition. Taken together, our results suggest that surround receptive fields of AII amacrine cells are generated indirectly by the GABAergic, reciprocal feedback synapses from S1/S2 amacrine cells to the axon terminals of rod bipolar cells.

  2. TSAR modeling of a TEM horn and surrounding structure

    Science.gov (United States)

    Ng, W. C.; Pennock, S. T.

    1993-11-01

    Modeling of a TEM horn was performed with the TSAR FDTD electromagnetics code. The modeling was done in stages, beginning with the simplest case, the bare antenna itself. Complexity was added in the form of a dielectric lens, an enclosing cylinder, a layer of absorber inside the cylinder, resistive terminations between the horn and cylinder, and a flat plate over all, electrically separate from the cylinder. The final configuration included all of the above, plus a ring of ferrite inside the cylinder, just ahead of the horn. Predictions of the far-field were made at roughly ten degree increments, more closely spaced near boresight, in both vertical and horizontal planes, through the antenna's centerline. Time histories at those points were evaluated, and from the time histories power densities were calculated. Both time histories and power densities will be presented for the configurations modeled.

  3. Particle flows to shape and voltage surface discontinuities in the electron sheath surrounding a high voltage solar array in LEO

    Science.gov (United States)

    Metz, Roger N.

    1991-01-01

    This paper discusses the numerical modeling of electron flows from the sheath surrounding high positively biased objects in LEO (Low Earth Orbit) to regions of voltage or shape discontinuity on the biased surfaces. The sheath equations are derived from the Two-fluid, Warm Plasma Model. An equipotential corner and a plane containing strips of alternating voltage bias are treated in two dimensions. A self-consistent field solution of the sheath equations is outlined and is pursued through one cycle. The electron density field is determined by numerical solution of Poisson's equation for the electrostatic potential in the sheath using the NASCAP-LEO relation between electrostatic potential and charge density. Electron flows are calculated numerically from the electron continuity equation. Magnetic field effects are not treated.

  4. Potential Roles of the Interaction Between Model V1 Neurons with Orientation-Selective and Non-selective Surround Inhibition in Contour Detection

    Directory of Open Access Journals (Sweden)

    Kai-Fu eYang

    2015-06-01

    Full Text Available Both the neurons with orientation-selective and with non-selective surround inhibition have been observed in the primary visual cortex (V1 of primates and cats. Though the inhibition coming from the surround region (named as non-classical receptive field, nCRF has been considered playing critical role in visual perception, the specific role of orientation-selective and non-selective inhibition in the task of contour detection is less known. To clarify above question, we first carried out computational analysis of the contour detection performance of V1 neurons with different types of surround inhibition, on the basis of which we then proposed two integrated models to evaluate their role in this specific perceptual task by combining the two types of surround inhibition with two different ways. The two models were evaluated with synthetic images and a set of challenging natural images, and the results show that both of the integrated models outperform the typical models with orientation-selective or non-selective inhibition alone. The findings of this study suggest that V1 neurons with different types of center-surround interaction work in cooperative and adaptive ways at least when extracting organized structures from cluttered natural scenes. This work is expected to inspire efficient phenomenological models for engineering applications in field of computational machine-vision.

  5. Issues surrounding the health economic evaluation of genomic technologies.

    Science.gov (United States)

    Buchanan, James; Wordsworth, Sarah; Schuh, Anna

    2013-11-01

    Genomic interventions could enable improved disease stratification and individually tailored therapies. However, they have had a limited impact on clinical practice to date due to a lack of evidence, particularly economic evidence. This is partly because health economists are yet to reach consensus on whether existing methods are sufficient to evaluate genomic technologies. As different approaches may produce conflicting adoption decisions, clarification is urgently required. This article summarizes the methodological issues associated with conducting economic evaluations of genomic interventions. A structured literature review was conducted to identify references that considered the methodological challenges faced when conducting economic evaluations of genomic interventions. Methodological challenges related to the analytical approach included the choice of comparator, perspective and timeframe. Challenges in costing centered around the need to collect a broad range of costs, frequently, in a data-limited environment. Measuring outcomes is problematic as standard measures have limited applicability, however, alternative metrics (e.g., personal utility) are underdeveloped and alternative approaches (e.g., cost-benefit analysis) underused. Effectiveness data quality is weak and challenging to incorporate into standard economic analyses, while little is known about patient and clinician behavior in this context. Comprehensive value of information analyses are likely to be helpful. Economic evaluations of genomic technologies present a particular challenge for health economists. New methods may be required to resolve these issues, but the evidence to justify alternative approaches is yet to be produced. This should be the focus of future work in this field.

  6. Study and Application on Stability Classification of Tunnel Surrounding Rock Based on Uncertainty Measure Theory

    Directory of Open Access Journals (Sweden)

    Hujun He

    2014-01-01

    Full Text Available Based on uncertainty measure theory, a stability classification and order-arranging model of surrounding rock was established. Considering the practical engineering geologic condition, 5 factors that influence surrounding rock stability were taken into account and uncertainty measure function was obtained based on the in situ data. In this model, uncertainty influence factors were analyzed quantitatively and qualitatively based on the real situation; the weight of index was given based on information entropy theory; surrounding rock stability level was judged based on credible degree recognition criterion; and surrounding rock was ordered based on order-arranging criterion. Furthermore, this model was employed to evaluate 5 sections surrounding rock in Dongshan tunnel of Huainan. The results show that uncertainty measure method is reasonable and can have significance for surrounding rock stability evaluation in the future.

  7. Mineralogical and microstructural investigations of fractures in Permian z2 potash seam and surrounding salt rocks

    Science.gov (United States)

    Mertineit, Michael; Grewe, Wiebke; Schramm, Michael; Hammer, Jörg; Blanke, Hartmut; Patzschke, Mario

    2017-04-01

    Fractures occur locally in the z2 potash seam (Kaliflöz Staßfurt). Most of them extend several centimeter to meter into the surrounding salt rocks. The fractures are distributed on all levels in an extremely deformed area of the Morsleben salt mine, Northern Germany. The sampling site is located within a NW-SE trending synclinal structure, which was reverse folded (Behlau & Mingerzahn 2001). The samples were taken between the -195 m and - 305 m level at the field of Marie shaft. In this area, more than 200 healed fractures were mapped. Most of them show opening widths of only a few millimeters to rarely 10 cm. The fractures in rock salt are filled with basically polyhalite, halite and carnallite. In the potash seam, the fractures are filled with kainite, halite and minor amounts of carnallite and polyhalite. In some cases the fracture infill changes depending on the type of surrounding rocks. There are two dominant orientations of the fractures, which can be interpreted as a conjugated system. The main orientation is NE-SW trending, the dip angles are steep (ca. 70°, dip direction NW and SE, respectively). Subsequent deformation of the filled fractures is documented by a strong grain shape fabric of kainite, undulatory extinction and subgrain formation in kainite, and several mineral transformations. Subgrain formation in halite occurred in both, the fracture infill and the surrounding salt rocks. The results correlate in parts with investigations which were carried out at the close-by rock salt mine Braunschweig-Lüneburg (Horn et al. 2016). The development of the fractures occurred during compression of clayey salt rocks. However, the results are only partly comparable due to different properties (composition, impurities) of the investigated stratigraphic units. Further investigations will focus on detailed microstructural and geochemical analyses of the fracture infill and surrounding salt rocks. Age dating of suitable minerals, e.g. polyhalite (Leitner et al

  8. Controversy surrounding the increased expression of TGFβ1 in asthma

    Directory of Open Access Journals (Sweden)

    Rola-Pleszczynski Marek

    2007-09-01

    Full Text Available Abstract Asthma is a waxing and waning disease that leads to structural changes in the airways, such as subepithelial fibrosis, increased mass of airway smooth muscle and epithelial metaplasia. Such a remodeling of the airways futher amplifies asthma symptoms, but its etiology is unknown. Transforming growth factor β1 is a pleiotropic cytokine involved in many fibrotic, oncologic and immunologic diseases and is believed to play an essential role in airway remodeling that occurs in asthmatic patients. Since it is secreted in an inactive form, the overall activity of this cytokine is not exclusively determined by its level of expression, but also by extensive and complex post-translational mechanisms, which are all importanin modulating the magnitude of the TGFβ1 response. Even if TGFβ1 upregulation in asthma is considered as a dogma by certain investigators in the field, the overall picture of the published litterature is not that clear and the cellular origin of this cytokine in the airways of asthmatics is still a contemporaneous debate. On the other hand, it is becoming clear that TGFβ1 signaling is increased in the lungs of asthmatics, which testifies the increased activity of this cytokine in asthma pathogenesis. The current work is an impartial and exhaustive compilation of the reported papers regarding the expression of TGFβ1 in human asthmatics. For the sake of comparison, several studies performed in animal models of the disease are also included. Inconsistencies observed in human studies are discussed and conclusions as well as trends from the current state of the litterature on the matter are proposed. Finally, the different points of regulation that can affect the amplitude of the TGFβ1 response are briefly revised and the possibility that TGFβ1 is disregulated at another level in asthma, rather than simply in its expression, is highlighted.

  9. Comparison of Socioeconomic Factors between Surrounding and Non-Surrounding Areas of the Qinghai–Tibet Railway before and after Its Construction

    Directory of Open Access Journals (Sweden)

    Shicheng Li

    2016-08-01

    Full Text Available As the world’s highest railway, and the longest highland railway, the Qinghai–Tibet Railway (QTR has been paid considerable attention by researchers. However, most attention has been paid to the ecological and environmental issues affecting it, and sustainable ecological, social, and economic development-related studies of the QTR are rare. In this study, by analyzing the passenger traffic, freight traffic, passenger-kilometers, and freight-kilometers of the QTR for the period 1982–2013 and the transport structure of the Tibetan Plateau (TP for 1990–2013, the evolutionary process of the transport system in the TP following the construction of the QTR has been revealed. Subsequently, by comparing Gross Domestic Product (GDP, population, industrial structure, and urbanization level at the county and 1 km scales between surrounding and non-surrounding areas of the QTR, the differences in socioeconomic performance before and after its construction were detected. The results show that (1 in the TP, the highway-dominated transport system will break up and an integrated and sustainable transport system will form; (2 at the county scale, the annual growth rates of GDP of counties surrounding the QTR were greater than those of non-surrounding counties for the period 2000–2010. At the 1 km scale, following the opening of the completed line, the GDP of surrounding areas had a greater growth rate than before; (3 analysis at the county and 1 km scales indicated that population was not aggregated into the surrounding areas of the QTR in the period 2000–2010; (4 in terms of industrial structure, the proportion of primary industry decreased continuously, while the proportion of secondary and tertiary industries increased overall in the period 1984–2012. The QTR had no obvious impact on changes in the urbanization level of its surrounding areas.

  10. Information support of territorial wildlife management of Lake Baikal and the surrounding areas (Russia)

    Science.gov (United States)

    Lesnykh, Svetlana

    2013-04-01

    The UNESCO World Heritage Committee inscribed Lake Baikal in the World Heritage List under all four natural criteria as the most outstanding example of a freshwater ecosystem. It is the oldest and deepest lake in the world, which is the main freshwater reserve surrounded by a system of protected areas that have high scientific and natural values. However, there is a conflict between three main interests within the territory: the preservation of the unique ecosystem of the lake and its surrounding areas, the need for regional economic development, and protection of interests of the population, living on the shores of Lake Baikal. Solutions to the current challenges are seen in the development of control mechanisms for the wildlife management to ensure sustainable development and conservation of lake and the surrounding regions. For development mechanisms of territorial management of the complex and valuable area it is necessary to analyze features of its functioning and self-control (adaptable possibilities), allowing ecosystems to maintain their unique properties under influence of various external factors: anthropogenic (emissions, waste water, streams of tourists) and natural (climate change) load. While determining the direction and usage intensity of the territory these possibilities and their limits should be considered. Also for development of management strategy it is necessary to consider the relation of people to land and water, types of wildlife management, ownership, rent, protection from the negative effects, and etc. The relation of people to the natural area gives a chance to prioritize the direction in the resource use and their protection. Results of the scientific researches (reaction of an ecosystem on influence of various factors and system of relations to wildlife management objects) are the basis for the nature protection laws in the field of wildlife management and environmental protection. The methodology of legal zoning of the territory was

  11. Dark-field hyperlens for high-contrast sub-wavelength imaging

    DEFF Research Database (Denmark)

    Repän, Taavi; Zhukovsky, Sergei; Lavrinenko, Andrei

    2016-01-01

    By now superresolution imaging using hyperbolic metamaterial (HMM) structures – hyperlenses – has been demonstrated both theoretically and experimentally. The hyperlens operation relies on the fact that HMM allows propagation of waves with very large transverse wavevectors, which would be evanesc......By now superresolution imaging using hyperbolic metamaterial (HMM) structures – hyperlenses – has been demonstrated both theoretically and experimentally. The hyperlens operation relies on the fact that HMM allows propagation of waves with very large transverse wavevectors, which would...... be evanescent in common isotropic media (thus giving rise to the diffraction limit). However, nearly all hyperlenses proposed so far have been suitable only for very strong scatterers – such as holes in a metal film. When weaker scatterers, dielectric objects for example, are imaged then incident light forms...... a very strong background, and weak scatterers are not visible due to a poor contrast. We propose a so-called dark-field hyperlens, which would be suitable for imaging of weakly scattering objects. By designing parameters of the HMM, we managed to obtain its response in such way that the hyperlens...

  12. Motion transduction in nanoelectromechanical systems (NEMS) arrays using near-field optomechanical coupling.

    Science.gov (United States)

    Basarir, O; Bramhavar, S; Ekinci, K L

    2012-02-08

    Development of efficient and sensitive motion transducers for arrays of nanoelectromechanical systems (NEMS) is important for fundamental research as well as for technological applications. Here, we report a single-wire nanomechanical transducer interface, which relies upon near-field optomechanical interactions. This multiplexed transducer interface comes in the form of a single-mode fiber taper on a fiber-optic cable. When the fiber taper is positioned sufficiently close to the NEMS array such that it can attain evanescent optical coupling with the array, individual NEMS resonances can be actuated using optical dipole forces. In addition, sensitive detection of nanomechanical motion can be realized when the evanescent waves confined around the taper are scattered by the motion. We have measured resonances from an array of 63 NEMS resonators with a displacement sensitivity of 2-8 pm·Hz(-1/2) at a detection power of ~100 μW (incident on the entire array). © 2012 American Chemical Society

  13. Shaded relief magnetic anomaly map of Italy and surrounding marine areas

    Directory of Open Access Journals (Sweden)

    C. Carmisciano

    2000-06-01

    Full Text Available Magnetic observations made onshore the Italian Peninsula, and across the adjacent seas, have been compiled in a new digital database that provides the first complete regional scale view of the crustal scale magnetic anomalies of the region at sea level. The offshore data were acquired between 1965-1972 by the Osservatorio Geofisico Sperimentale (OGS while the ground measurements were performed within the framework of the Progetto Finalizzato Geodinamica of the Consiglio Nazionale delle Ricerche (PFG-CNR between 1977 and 1981. The new shaded relief magnetic anomaly map of total intensity of the Earth's magnetic field for Italy and the surrounding seas has been produced at sea level, for the geomagnetic epoch 1979.0. The most remarkable result of this new map, with respect to the previous compilations and to the aeromagnetic map of Italy, is an unprecedented view of the magnetic signature of the major tectonic elements in their regional setting. There is good correlation between known structural geology and the magnetic anomalies, and now that the longer wavelength signatures have been corrected, deeper interpretations are possible.

  14. Effects of the surroundings and conformerisation of n-dodecane molecules on evaporation/condensation processes

    Energy Technology Data Exchange (ETDEWEB)

    Gun’ko, Vladimir M. [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, Kiev 03164 Ukraine (Ukraine); Sir Harry Ricardo Laboratories, School of Computing, Engineering and Mathematics, University of Brighton, Cockcroft Building, Lewes Road, Brighton BN2 4GJ (United Kingdom); Nasiri, Rasoul; Sazhin, Sergei S., E-mail: S.Sazhin@brighton.ac.uk [Sir Harry Ricardo Laboratories, School of Computing, Engineering and Mathematics, University of Brighton, Cockcroft Building, Lewes Road, Brighton BN2 4GJ (United Kingdom)

    2015-01-21

    The evaporation/condensation coefficient (β) and the evaporation rate (γ) for n-dodecane vs. temperature, gas pressure, gas and liquid density, and solvation effects at a droplet surface are analysed using quantum chemical density functional theory calculations of several ensembles of conformers of n-dodecane molecules in the gas phase (hybrid functional ωB97X-D with the cc-pVTZ and cc-pVDZ basis sets) and in liquid phase (solvation method: SMD/ωB97X-D). It is shown that β depends more strongly on a number of neighbouring molecules interacting with an evaporating molecule at a droplet surface (this number is estimated through changes in the surface Gibbs free energy of solvation) than on pressure in the gas phase or conformerisation and cross-conformerisation of molecules in both phases. Thus, temperature and the surrounding effects at droplet surfaces are the dominant factors affecting the values of β for n-dodecane molecules. These values are shown to be similar (at reduced temperatures T/T{sub c} < 0.8) or slightly larger (at T/T{sub c} > 0.8) than the values of β calculated by the molecular dynamics force fields (MD FF) methods. This endorses the reliability of the previously developed classical approach to estimation of β by the MD FF methods, except at temperatures close to the critical temperature.

  15. Mapping soils in two watersheds using legacy data and extrapolation for similar surrounding areas

    Directory of Open Access Journals (Sweden)

    Marcelo Henrique Procópio Pelegrino

    Full Text Available ABSTRACT Existing soil maps (legacy data associated with digital mapping techniques are alternatives to obtain information at lower costs, however, tests are required to do it more efficiently. This study had as objectives to compare different methods to extract information from detailed scale soil maps using decision trees for mapping soil classes at two watersheds in Minas Gerais, validate these maps in the field and use the best method to extrapolate information to larger areas, also validating these maps of larger areas. Detailed soil maps of Vista Bela creek (VBW and Marcela creek (MCW watersheds were used as source of information. Seven methods to extract information from maps were compared: the whole polygon, eliminating 20 and 40 m from the polygon boundaries, and with buffers around the sampled points with radii of 25 m, 50 m, 75 m, and 100 m. The Classification and Regression Trees (CART algorithm was employed to create decision trees and enable creation of soil maps. Accuracy was assessed through overall accuracy and kappa index. The best method was used to extrapolate information to larger areas and maps were validated. The best methods for VCW and MCW were, respectively, eliminating 20 m from polygon edges and buffer of 25 m of radii from points. Maps for larger areas were obtained using these methods. Removing uncertainty areas from legacy soil maps contribute to better modeling and prediction of soil classes. Information generated in this work allowed for validated extrapolation of soil maps for regions surrounding the watersheds.

  16. Animals and their products utilized as medicines by the inhabitants surrounding the Ranthambhore National Park, India

    Directory of Open Access Journals (Sweden)

    Jaroli DP

    2006-11-01

    Full Text Available Abstract The present ethnozoological study describes the traditional knowledge related to the use of different animals and animal-derived products as medicines by the inhabitants of villages surrounding the Ranthambhore National Park of India (Bawaria, Mogya, Meena, which is well known for its very rich biodiversity. The field survey was conducted from May to July 2005 by performing interviews through structured questionnaires with 24 informants (16 men and 8 women, who provided information regarding therapeutic uses of animals. A total of 15 animals and animal products were recorded and they are used for different ethnomedical purposes, including tuberculosis, asthma, paralysis, jaundice, earache, constipation, weakness, snake poisoning. The zootherapeutic knowledge was mostly based on domestic animals, but some protected species like the collared dove (Streptopelia sp., hard shelled turtle (Kachuga tentoria, sambhar (Cervus unicolor were also mentioned as important medicinal resources. We would suggest that this kind of neglected traditional knowledge should be included into the strategies of conservation and management of faunistic resources in the investigated area.

  17. Properties of Schist Extracted in the City of Denizli Surroundings as Construction Material

    Directory of Open Access Journals (Sweden)

    Saffet Yağız

    2011-03-01

    Full Text Available There are various type of building stone extracted at stone quarries in the city of Denizli surroundings. Travertine, limestone and schist quarries are the most common in the area. Schist that is one of the units of Menderes massive is the main natural stone sources in Çal, Bekilli and Baklan Triangle in the northeast of the City. The aim of this study is to investigate the usability of schist stone as building stone quarried in the area. To obtain the aim, geological investigations were conducted in the field and representative samples were collected from the quarries. On the samples, petrograpical, mineralogical (XRD, chemical (XRF analysis and geomechanical test (i.e., uniaxial compressive strength, Schmidt hardness, water absorption by weight, effective porosity, fullness ratio, flexural strength, sonic wave velocity, modulus of elasticity, natural and saturated unit weight were conducted and the usability of schist stone as building stone have been studied by evaluating obtained findings. Analysis and relevant tests were conducted in accordance with international standards and procedures. Concluding remark is that quarried schist stone in the area are acceptably good as building stone to be used for both interior and exterior of construction building and outdoors as coverage material.

  18. Irradiation of Population in the Surrounding Area of Nuclear Power Plant Temelin

    Science.gov (United States)

    Thinova, Lenka; Kluson, Jaroslav

    2008-08-01

    In monitoring the impact of nuclear facilities operation on ecosystem, it is necessary to consider, what part of biota irradiation can be caused by an artificial source. For the estimation of an effective dose from natural sources were used measurements of dosimetric and gamma spectrometric characteristics of photon fields, (performed in the area of NPP Temelin since year 2000) and data from the Czech Republic radiometric chart, including the results from radon volume activity measurements in dwellings. For gamma spectrometric measurements in situ were selected two methodologies and for measurement were used corresponding types of equipment (Tesla NB3201 and spectrometer NaI(TI) 3"x3") at selected locations within the monitored area: i) determination of air kerma rate (through direct measurement and by calculationfrom spectrometric data); ii) measurement of photon spectra by an scintillating spectrometer. For a dose assessment from artificial sources resulting from past or present operation of NPP Temelin, were used records from all so far performed laboratory and field measurements of NPP releases, food baskets and also results of a 6 year ecosystem monitoring in the surrounding area of NPP Temelin. The ecosystem monitoring is based on studying the contamination of the following bioindicators: forest humus, Pine bark, Schreber's Moss, the Bay Bolete (mushroom) and forest berries. Each year 220 samples are collected and mass activity (Bq/kg) for eventual contaminants is determined using laboratory gamma spectroscopy. For measurements is used a coaxial HPGe detector, with samples in the geometry of "Marinelli" container. For evaluation of the laboratory results obtained is used trend analysis. The above described monitoring has been performed from the year 2000 until now (the year 2000 is pre-operational). In all measured laboratory spectra, of all analyzed samples, were not identified any non-natural radionuclides, with the exception of 137Cs, for which maesured

  19. The Effect of Integrated Hearing Protection Surround Levels on Sound Localization

    Science.gov (United States)

    2015-02-01

    Carmichael, E.L., Harris, F.P., Story, B.H.: Effects of binaural electronic hearing protectors on localization and response time to sounds in the horizontal...The effect of integrated hearing protection surround levels on sound localization Sharon M. Abel, Craig Burrell, Douglas...The effect of integrated hearing protection surround levels on sound localization Sharon M. Abel, Craig

  20. 75 FR 82407 - Submission for OMB Review; Comment Request; Testing Successful Health Communications Surrounding...

    Science.gov (United States)

    2010-12-30

    ... Successful Health Communications Surrounding Aging-Related Issues From the National Institute on Aging (NIA... number. Proposed Collection: Title: Testing successful health communications surrounding aging-related.../development of health messages and communications strategies; Pre-test health messages and outreach strategies...

  1. 3DCRT for posterior fossa: Sparing of surrounding organs at risk ...

    African Journals Online (AJOL)

    ... adequate coverage of the target volume while sparing of the cochlea and other surrounding organs at risk (OARs) at same time inevitable. Aim of the work: To compare the coverage of posterior fossa and the dose to surrounding OARs including non-posterior fossa brain, pituitary, cochlea, eyes, optic nerves, optic chiasm, ...

  2. Different surrounding landscapes may result in different fish assemblages in East African seagrass beds

    NARCIS (Netherlands)

    Dorenbosch, M.; Grol, M.G.G.; Nagelkerken, I.; Velde, G. van der

    2006-01-01

    Few studies have considered how seagrass fish assemblages are influenced by surrounding habitats. This information is needed for a better understanding of the connectivity between tropical coastal ecosystems. To study the effects of surrounding habitats on the composition, diversity and densities of

  3. Electrophysiological evidence for the action of a center-surround mechanism on semantic processing in the left hemisphere

    Directory of Open Access Journals (Sweden)

    Diana eDeacon

    2013-12-01

    Full Text Available Physiological evidence was sought for a center-surround attentional mechanism (CSM, which has been proposed to assist in the retrieval of weakly activated items from semantic memory. The CSM operates by facilitating strongly related items in the center of the weakly activated area of semantic memory, and inhibiting less strongly related items in its surround. In this study weak activation was created by having subjects acquire the meanings of new words to a recall criterion of only 50%. Subjects who attained this approximate criterion level of performance were subsequently included in a semantic priming task, during which ERPs were recorded. Primes were newly learned rare words, and targets were either synonyms, nonsynonymously related words, or unrelated words. All stimuli were presented to the RVF/LH (right visual field/left hemisphere or the LVF/RH (left visual field/right hemisphere. Under RVF/LH stimulation the newly learned word primes produced facilitation on N400 for synonym targets, and inhibition for related targets. No differences were observed under LVF/RH stimulation. The LH thus, supports a CSM, whereby a synonym in the center of attention focused on the newly learned word is facilitated, whereas a related word in the surround is inhibited. The data are consistent with the view of this laboratory that semantic memory is subserved by a spreading activation system in the LH. Also consistent with our view, there was no evidence of spreading activation in the RH. The findings are discussed in the context of additional recent theories of semantic memory. Finally, the adult right hemisphere may require more learning than the LH in order to demonstrate evidence of meaning acquisition.

  4. Hydromagnetic Waves in a Compressed Dipole Field via Field-Aligned Klein-Gordon Equations

    CERN Document Server

    Zheng, Jinlei; McKenzie, J F; Webb, G M

    2014-01-01

    Hydromagnetic waves, especially those of frequencies in the range of a few milli-Hz to a few Hz observed in the Earth's magnetosphere, are categorized as Ultra Low Frequency (ULF) waves or pulsations. They have been extensively studied due to their importance in the interaction with radiation belt particles and in probing the structures of the magnetosphere. We developed an approach in examining the toroidal standing Aflv\\'{e}n waves in a background magnetic field by recasting the wave equation into a Klein-Gordon (KG) form along individual field lines. The eigenvalue solutions to the system are characteristic of a propagation type when the corresponding eigen-frequency is greater than a cut-off frequency and an evanescent type otherwise. We apply the approach to a compressed dipole magnetic field model of the inner magnetosphere, and obtain the spatial profiles of relevant parameters and the spatial wave forms of harmonic oscillations. We further extend the approach to poloidal mode standing Alfv\\'{e}n waves...

  5. Activity and population dynamics of heterotrophic and ammonia-oxidizing microorganisms in soil surrounding sludge bands spiked with linear alkylbenzene sulfonate

    DEFF Research Database (Denmark)

    Brandt, K. K.; Sørensen, J.; Krogh, P. H.

    2003-01-01

    in a sandy soil surrounding well-defined sludge bands spiked with high but realistic LAS levels (7.1 or 31.3 g/kg). Surprisingly, LAS had no effect on heterotrophic respiration in the sludge compartment per se but stimulated activity and metabolic quotient (microbial activity per unit of biomass......Recent research has documented soil microorganisms to be rather sensitive to linear alkylbenzene sulfonates (LAS), which may enter the soil environment in considerable quantities following sewage sludge disposal. We here report field effects of LAS on selected microbial populations present......) in the surrounding soil. By contrast, autotrophic ammonia oxidation was initially inhibited in the LAS-spiked sludge. This led to dramatic transient increases of NH+4 availability in the sludge and surrounding soil, subsequently stimulating soil ammonia oxidizers. As judged from a Nitrosomonas europaea...

  6. Varieties of Quest and the Religious Openness Hypothesis within Religious Fundamentalist and Biblical Foundationalist Ideological Surrounds

    Directory of Open Access Journals (Sweden)

    P. J. Watson

    2013-12-01

    Full Text Available According to the Religious Openness Hypothesis, the religious and psychological openness of American Christians is obscured by a defensive ghettoization of thought associated with a Religious Fundamentalist Ideological Surround and can be discovered instead within a Biblical Foundationalist Ideological Surround. A test of this claim examined Religious Fundamentalism, Biblical Foundationalism, Quest, and Multidimensional Quest Scales in 432 undergraduates. Christian Religious Reflection, Religious Schema, and Religious Orientation measures clarified these two ideological surrounds. Partial correlations controlling for Biblical Foundationalism described a Religious Fundamentalist Ideological Surround that more strongly rejected Quest and that more generally displayed a failure to integrate faith with intellect. Partial correlations controlling for Religious Fundamentalism revealed a Biblical Foundationalist Ideological Surround that was more open to Quest and that offered numerous demonstrations of an ability to unite faith with intellect. These data supplemented previous investigations in demonstrating that Christianity and other traditional religions have ideological resources for promoting a faithful intellect.

  7. Dipole force free optical control and cooling of nanofiber trapped atoms

    DEFF Research Database (Denmark)

    Østfeldt, Christoffer; Béguin, Jean-Baptiste Sylvain; Pedersen, Freja Thilde

    2017-01-01

    The evanescent field surrounding nanoscale optical waveguides offers an efficient interface between light and mesoscopic ensembles of neutral atoms. However, the thermal motion of trapped atoms, combined with the strong radial gradients of the guided light, leads to a time-modulated coupling betw...

  8. Investigating effects of surrounding landscape composition and complexity on populations of two polyphagous insect pest groups in Iowa soybean

    Science.gov (United States)

    Kuntz, Cody Daniel

    The composition and complexity of agro-ecosystems are important factors influencing the population dynamics of insect pests. Understanding these interactions may improve our ability to predict the spatial occurrence of pest outbreaks, thereby informing scouting and management decisions. In 2012 and 2013, two concurrent studies were conducted to examine the relationship between landscapes surrounding Iowa soybean, Glycine max [L.] Merrill, fields and two polyphagous pest groups; Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), and stink bugs (Hemiptera: Pentatomidae). Population densities were monitored in soybean within simple and complex agricultural landscapes to determine the response of these pests to landscape complexity. Results revealed P. japonica populations were significantly greater in soybean fields within complex landscapes and were positively associated with area of uncultivated land. The specific compositions of surrounding landscapes were also analyzed to determine the landscape features that explain the greatest variation in P. japonica and stink bug population densities. Results suggested that the area of wooded and grass habitat around fields accounted for the greatest variation in P. japonica populations; however, no discernable relationships were observed with stink bug populations. Sampling also sought to survey the community of stink bugs present in Iowa soybean. The community was predominantly comprised of stink bugs in the genus Euschistus, comprising a combined 91.04% of all captures. Additional species included the green stink bug, Acrosternum hilare (Say) (4.48%); spined soldier bug, Podisus maculiventris (Say) (2.99%); and red shouldered stink bug, Thyanta custator accerra (McAtee) (1.49%). Future work will be needed to determine if the landscape effects on P. japonica in soybean reported here are representative of other similar polyphagous pests of soybean and if they extend to other host plants as well

  9. Characterization of the Capsule Surrounding Smooth and Textured Tissue Expanders and Correlation with Contracture

    Directory of Open Access Journals (Sweden)

    Erika Kuriyama, MD

    2017-07-01

    Full Text Available Background:. Capsular contracture is a common complication after breast augmentation surgery. This study pathologically evaluated the soft-tissue response to surface modifications in both smooth and textured tissue expander prostheses. Methods:. Smooth tissue expanders and textured tissue expanders in 5 cases each were used for breast reconstruction after mastectomy. Histological samples were harvested from the capsules when the tissue expanders were replaced by silicone implants. Collagen orientation and cellular responses were assessed histologically. Capsular contracture was evaluated using the Baker classification 6 months and 2 years after the removal of the tissue expander. Results:. The capsules surrounding the smooth tissue expanders tended to produce more contracture than those surrounding the textured tissue expanders. The collagen architecture of the capsules of the smooth tissue expanders showed random orientation with fragmentation. Conversely, the capsules of the textured tissue expanders showed parallel orientation with collagen bundles of almost normal structure. Significantly more fibrils of elastin and myofibroblasts were found in the capsules surrounding the smooth tissue than in those surrounding the textured ones. Conclusions:. The collagen fibers surrounding the smooth tissue expanders could be cracked during expansion, which may lead to scarring and contracture. Conversely, the collagen orientation surrounding the textured tissue expanders was excellent. Moreover, the increase in elastic fibers and myofibroblasts in the capsules surrounding the smooth tissue expanders may be associated with in vivo contraction patterns. Therefore, the surface type of tissue expanders affects capsular contraction after replacement with definitive implants.

  10. THE EMISSION NEBULA Sh 2-174: A RADIO INVESTIGATION OF THE SURROUNDING REGION

    Energy Technology Data Exchange (ETDEWEB)

    Ransom, R. R. [Department of Physics and Astronomy, Okanagan College, 583 Duncan Avenue West, Penticton, BC V2A 8E1 (Canada); Kothes, R.; Geisbuesch, J.; Landecker, T. L. [National Research Council Herzberg, Dominion Radio Astrophysical Observatory, P.O. Box 248, Penticton, BC V2A 6J9 (Canada); Reich, W., E-mail: RRansom@okanagan.bc.ca [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2015-02-01

    Sh 2-174 is believed to be either a planetary nebula (PN) or ionized, ambient interstellar medium (ISM). We present in this paper 1420 MHz polarization, 1420 MHz total intensity (Stokes-I), and neutral hydrogen (H I) images of the region around Sh 2-174. The radio images address not only the nature of the object, but also the history of the relationship between Sh 2-174 and its surrounding environment. The H I images show that Sh 2-174 sits presently at the center of a ∼1.°2 × ∼0.°4 cloud (with peak hydrogen density n {sub H} = 4 ± 2 cm{sup –3}). The Stokes-I image shows thermal-emission peaks (with electron densities n{sub e} = 11 ± 3 cm{sup –3}) coincident with the R-band optical nebula, as well as low-surface-brightness emission from an ionized ''halo'' around Sh 2-174 and from an ionized ''plateau'' extending southeast from the cloud. The polarization images reveal Faraday-rotation structures along the projected trajectory of Sh 2-174, including a high-contrast structure with ''arms'' that run precisely along the eastern edge of the H I cloud and a wide central region that merges with the downstream edge of Sh 2-174. The high-contrast structure is consistent with an ionized tail that has both early-epoch (before Sh 2-174 entered the cloud) and present-epoch (after Sh 2-174 entered the cloud) components. Furthermore, our rotation-measure analysis indicates that the ISM magnetic field is deflected at the leading edge of Sh 2-174. The downstream tail and upstream field deflection point to a PN-ISM interaction. Our estimated space velocity for the host white dwarf (GD 561) demonstrates that Sh 2-174 entered the cloud ∼27,000 yr ago, and gives a PN-ISM interaction timescale ≲ 2.0 × 10{sup 5} yr. We estimate an ambient magnetic field in the cloud of 11 ± 3 μG.

  11. Empathic surroundings

    NARCIS (Netherlands)

    Mihelj, M.; van den Broek, Egon

    2008-01-01

    In his new book (2007), Marvin Minsky states that Artificial Intelligence (AI) needs empathy to become truly smart, as is illustrated through human-human interaction. The latter also holds for Virtual Reality (VR), where the interest increases to unravel the emotional state of users has to be

  12. Automobile Optimal Driving Control Using Surrounding Information Based on Model Predictive Control

    Science.gov (United States)

    Wu, Dongmei; Xia, Yang; Ogawa, Masatoshi; Ogai, Harutoshi; Kawabe, Taketoshi

    In this paper, an optimal driving control system based on model predictive control (MPC) is developed for the purpose of processing more surrounding information which is essential for improving the current intelligent driving assistance and further dealing with traffic issues caused by automobiles. The proposed system provides a method of calculating a desirable driving path based on surrounding traffic environments. The performance of this system is evaluated through simulations which are carried out with introduction of surrounding information such as traffic jams, traffic signal changes, and fuel consumption. Simulation results reveal that the proposed system as a driving assist system has a potential of finding optimal driving paths for drivers.

  13. Dark-field hyperlens: Super-resolution imaging of weakly scattering objects

    DEFF Research Database (Denmark)

    Repän, Taavi; Lavrinenko, Andrei; Zhukovsky, Sergei

    2015-01-01

    : We propose a device for subwavelength optical imaging based on a metal-dielectric multilayer hyperlens designed in such a way that only large-wavevector (evanescent) waves are transmitted while all propagating (small-wavevector) waves from the object area are blocked by the hyperlens. We numeri...... to enhance the subwavelength image contrast by more than two orders of magnitude. These findings are essential for optical imaging of weakly scattering subwavelength objects, such as real-time dynamic nanoscopy of label-free biological objects....... numerically demonstrate that as the result of such filtering, the image plane only contains scattered light from subwavelength features of the objects and is completely free from background illumination. Similar in spirit to conventional dark-field microscopy, the proposed dark-field hyperlens is shown...

  14. Photonic forces in the near field of statistically homogeneous fluctuating sources

    CERN Document Server

    Aunon, Juan Miguel

    2012-01-01

    Electromagnetic sources, as e.g. lasers, antennas, diffusers or thermal sources, produce a wavefield that interacts with objects to transfer them its momentum. We show that the photonic force exerted on a small particle in the near field of a planar statistically homogeneous fluctuating source uniquely depends and acts along the coordinate perpendicular to its surface. The gradient part of this force is contributed by only the evanescent components of the emitted field, its sign being opposite to that of the real part of the particle polarizability. The non-conservative force part is uniquely due to the propagating components, being repulsive and constant. Also, the source coherence length adds a degree of freedom since it largely affects these forces. The excitation of plasmons in the source surface drastically enhances the gradient force. Hence, partially coherent wavefields from fluctuating sources constitute new concepts for particle manipulation at the subwavelength scale

  15. Graphene-based photovoltaic cells for near-field thermal energy conversion

    Science.gov (United States)

    Messina, Riccardo; Ben-Abdallah, Philippe

    2013-01-01

    Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat. PMID:23474891

  16. Control of radial propagation and polarity in a plasma jet in surrounding Ar

    Science.gov (United States)

    Gong, W.; Yue, Y.; Ma, F.; Yu, F.; Wan, J.; Nie, L.; Bazaka, K.; Xian, Y.; Lu, X.; Ostrikov, K.

    2018-01-01

    In recent years, the use of shielding gas to prevent the diffusion of the ambient air, particularly oxygen and nitrogen species, into the effluent of the atmospheric pressure plasma jet, and thus control the nature of chemical species used in the plasma treatment has increased. In this paper, the radial propagation of a plasma jet in ambient Ar is examined to find the key determinants of the polarity of plasma jets. The dynamics of the discharge reveal that the radial diffusion discharge is a special phenomenon observed only at the falling edge of the pulses. The radial transport of electrons, which is driven by the radial component of the applied electric field at the falling edge of the pulse, is shown to play an important role in increasing the seed electron density in the surrounding Ar. This result suggests a method to provide seed electrons at atmospheric pressure with a negative discharge. The polarity of the plasma jet is found to be determined by the pulse width rather than the polarity of the applied voltage, as it dictates the relative difference in the intensity of the two discharges in a single pulse, where the stronger discharge in a pulse dominates the behavior of the plasma jet. Accordingly, a method to control the polarity of a plasma jet through varying the pulse width is developed. Since plasma jets of different polarities differ remarkably in terms of their characteristics, the method to control the polarity reported in this paper will be of use for such applications as plasma-enhanced processing of materials and plasma biomedicine.

  17. Analysing land cover and land use change in the Ruma National Park and surroundings in Kenya

    Science.gov (United States)

    Scharsich, Valeska; Ochuodho Otieno, Dennis; Bogner, Christina

    2017-04-01

    The change of land use and land cover (LULC) is often driven by the growth of human population. In the Lambwe valley, Kenya, the most important reason for accelerated settlement in the last decades was the control of the tsetse fly, the biological vector of trypanosomes. Since the huge efforts of tsetse control in the 1970s, the population of the Lambwe valley in Kenya increased rapidly and therefore the cultivated area expanded. This amplified the pressure on the forested areas at higher elevations and the Ruma National Park which occupies one third of the Lambwe valley. Here, we investigate possible effects of this pressure on the land cover in the Lambwe valley and in particular in the Ruma National Park. To answer this question, we analysed the surface reflectance of three Landsat images of Ruma National Park and its surroundings from 1984, 2002 and 2014. To compensate for the lack of ground data we inferred past land use and land cover from recent observations combining Google Earth images and change detection. By supervised classification with Random Forests, we identified four land use and land cover types, namely the forest dominant at the high elevation; dense shrub land; savanna; and sparsely covered soil including bare light soils with little vegetation, fields and settlements. Subsequently, we compared the three classifications and identified LULC changes that occurred between 1984 and 2014. We observed an increase of agricultural area in the western part of the Lambwe valley, where high elevation vegetation was dominant. This goes hand in hand with farming on higher slopes and a decrease of forest. In the National Park itself the savanna increased by about 8% and the proportion of sparsely covered soil decreased by about 10%. This might be due to the fire management in the park and the recovering of burned areas.

  18. Control of radial propagation and polarity in a plasma jet in surrounding Ar

    KAUST Repository

    Gong, W.

    2018-01-08

    In recent years, the use of shielding gas to prevent the diffusion of the ambient air, particularly oxygen and nitrogen species, into the effluent of the atmospheric pressure plasma jet, and thus control the nature of chemical species used in the plasma treatment has increased. In this paper, the radial propagation of a plasma jet in ambient Ar is examined to find the key determinants of the polarity of plasma jets. The dynamics of the discharge reveal that the radial diffusion discharge is a special phenomenon observed only at the falling edge of the pulses. The radial transport of electrons, which is driven by the radial component of the applied electric field at the falling edge of the pulse, is shown to play an important role in increasing the seed electron density in the surrounding Ar. This result suggests a method to provide seed electrons at atmospheric pressure with a negative discharge. The polarity of the plasma jet is found to be determined by the pulse width rather than the polarity of the applied voltage, as it dictates the relative difference in the intensity of the two discharges in a single pulse, where the stronger discharge in a pulse dominates the behavior of the plasma jet. Accordingly, a method to control the polarity of a plasma jet through varying the pulse width is developed. Since plasma jets of different polarities differ remarkably in terms of their characteristics, the method to control the polarity reported in this paper will be of use for such applications as plasma-enhanced processing of materials and plasma biomedicine.

  19. Effect of Stresses and Strains of Roadway Surrounding Rocks on Borehole Airtightness

    Directory of Open Access Journals (Sweden)

    WU Wei

    2016-02-01

    Full Text Available At present, many high gas and outburst mines have poor gas drainage effects. An important reason influencing the gas drainage effect is a poor hole-sealing effect. Most studies on gas drainage borehole sealing focus on local and foreign borehole sealing methods, borehole sealing equipment, and borehole sealing materials. Numerical simulations of initial drilling sealing depth are insufficient because studies on this subject are few. However, when the initial sealing depth of the borehole is not chosen reasonably, air can enter the gas drainage drill hole through the circumferential crack of roadway surrounding rocks under the influence of suction pressure of the drainage system. This phenomenon ultimately affects the hole-sealing effect. To improve the drilling hole sealing of gas drainage boring, we deduced the expression formulas of the crushing zone, plastic zone, and elastic zone around the coal-seam floor stone drift and conducted a stress–strain analysis of the coal-seam floor stone drift of the 2145 working surfaces of the Sixth Coal Mine of Hebi Coal Mine Group Company by using theoretical analysis, numerical simulation, and on-scene verification. Finally, we obtain the initial drilling sealing depth, which is a main contribution of this study. The results prove the following. The performed hole-sealing process with an initial drilling sealing depth of 8 m has a gas drainage efficiency of 55%. Compared with the previous 6.8 m initial drilling sealing depth with a gas drainage efficiency of less than 30%, which was adopted by the mine, the initial sealing depth of 8 m chosen in the numerical simulation is reasonable and conforms to the actual situation on the spot. Therefore, the initial drilling sealing depth chosen in the numerical simulation will produce practical and effective guidance to study the field hole-sealing depth.

  20. Young stars and brown dwarfs surrounding Alnilam (ɛ Orionis) and Mintaka (δ Orionis)

    Science.gov (United States)

    Caballero, J. A.; Solano, E.

    2008-07-01

    Aims: We look for new regions to search for substellar objects. Methods: Two circular areas, 45 arcmin-radius each, centred on the young massive star systems Alnilam and Mintaka in the Orion Belt, were explored. The regions are very young (less than 10 Ma), have low extinction, and are neighbours to σ Orionis (~3 Ma), a young open cluster very rich in brown dwarfs and planetary-mass objects. We used Virtual Observatory tools, the astro-photometric Tycho-2, DENIS and 2MASS catalogues, 10 control fields at similar galactic latitudes, as well as X-ray, mid-infrared, and spectroscopic data from the literature. Results: We compiled exhaustive lists of known young stars and new candidate members in the Ori OB1b association and of fore- and background sources. A total of 136 stars display features of extreme youth, like early spectral types, lithium in absorption, or mid-infrared flux excess. Other two young brown dwarf and 289 star candidates have been identified from an optical/near-infrared colour-magnitude diagram. We list another 74 known objects that might belong to the association. This catalogue can serve as input for characterising the stellar and high-mass substellar populations in the Orion Belt. Finally, we investigated the surface densities and radial distributions of young objects surrounding Alnilam and Mintaka and compared them with those in the σ Orionis cluster. We report on a new open cluster centred on Mintaka. Conclusions: Both regions can be analogues to the σ Orionis cluster, but more massive, more extended, slightly older, and less radially concentrated. Tables A.1 to A.18 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/485/931

  1. Effect of surface contamination on osseointegration of dental implants surrounded by circumferential bone defects.

    LENUS (Irish Health Repository)

    Mohamed, Seif

    2010-05-01

    This study was designed to evaluate the effect of surface contamination on osseointegration of dental implants surrounded by a circumferential bone defect and to compare osseointegration around Osseotite with that around Nanotite implants.

  2. Hurricane Dennis Aerial Photography: Draft Image Mosaics of the Florida Panhandle and Surrounding Regions After Landfall

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The imagery posted on this site is of the Florida panhandle and surrounding regions after Hurricane Dennis made landfall. The regions photographed range from...

  3. The relation between residential property and its surroundings and day- and night-time residential burglary

    NARCIS (Netherlands)

    Montoya, Lorena; Junger, Marianne; Ongena, Yfke

    This article examines how residential property and its surroundings influence day- and night-time residential burglary. Crime Prevention Through Environmental Design (CPTED) principles of territoriality, surveillance, access control, target hardening, image maintenance, and activity support underpin

  4. Tropical Storm Ernesto Aerial Photography: Rapid Response Imagery of the Surrounding Regions After Landfall

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The imagery posted on this site is of the surrounding regions after Tropical Storm Ernesto made landfall. The aerial photography missions were conducted by the NOAA...

  5. A deformation mechanism of hard metal surrounded by soft metal during roll forming

    National Research Council Canada - National Science Library

    Yu, Hailiang; Tieu, A Kiet; Lu, Cheng; Liu, Xiong; Godbole, Ajit; Li, Huijun; Kong, Charlie; Qin, Qinghua

    2014-01-01

    .... The experimental results lead us to propose a new deformation mechanism for a hard metal surrounded by a soft metal during rolling of a laminated foil, particularly when the thickness of hard metal foil (Ti, 25 μm...

  6. Weakened Center-Surround Interactions in Visual Motion Processing in Schizophrenia

    National Research Council Canada - National Science Library

    Tadin, Duje; Kim, Jejoong; Doop, Mikisha L; Gibson, Crystal; Lappin, Joseph S; Blake, Randolph; Park, Sohee

    2006-01-01

    .... Center-surround suppression has been implicated in a range of visual functions, including figure-ground segregation and pursuit eye movements, visual functions that are impaired in schizophrenia...

  7. Hurricane Ike Aerial Photography: Rapid ResponseImagery of the Surrounding Regions After Landfall

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The imagery posted on this site is of the surrounding regionsafter Hurricane Ike made landfall. The aerial photography missions wereconducted by the NOAA Remote...

  8. Modelling of the effect of discontinuities on the extent of the fracture zone surrounding deep tunnels

    CSIR Research Space (South Africa)

    Sellers, EJ

    2000-10-01

    Full Text Available A series of physical and numerical model tests were performed to investigate the behaviour of the rock surrounding circular excavations under high confining pressures. The aim was to provide information on the formation of fractures around deep...

  9. Particulate capture efficiency of a vegetative environmental buffer surrounding an animal feeding operation

    Science.gov (United States)

    Particulate matter emitted from tunnel-ventilated animal feeding operations (AFOs) is known to transport malodorous compounds. As a mitigation strategy, vegetative environmental buffers (VEBs) are often installed surrounding AFOs to capture particulates and induce lofting and dispersion. Currently, ...

  10. Reduced visual surround suppression in schizophrenia shown by measuring contrast detection thresholds

    Science.gov (United States)

    Serrano-Pedraza, Ignacio; Romero-Ferreiro, Verónica; Read, Jenny C. A.; Diéguez-Risco, Teresa; Bagney, Alexandra; Caballero-González, Montserrat; Rodríguez-Torresano, Javier; Rodriguez-Jimenez, Roberto

    2014-01-01

    Visual perception in schizophrenia is attracting a broad interest given the deep knowledge that we have about the visual system in healthy populations. One example is the class of effects known collectively as visual surround suppression. For example, the visibility of a grating located in the visual periphery is impaired by the presence of a surrounding grating of the same spatial frequency and orientation. Previous studies have suggested abnormal visual surround suppression in patients with schizophrenia. Given that schizophrenia patients have cortical alterations including hypofunction of NMDA receptors and reduced concentration of GABA neurotransmitter, which affect lateral inhibitory connections, then they should be relatively better than controls at detecting visual stimuli that are usually suppressed. We tested this hypothesis by measuring contrast detection thresholds using a new stimulus configuration. We tested two groups: 21 schizophrenia patients and 24 healthy subjects. Thresholds were obtained using Bayesian staircases in a four-alternative forced-choice detection task where the target was a grating within a 3∘ Butterworth window that appeared in one of four possible positions at 5∘ eccentricity. We compared three conditions, (a) target with no-surround, (b) target embedded within a surrounding grating of 20∘ diameter and 25% contrast with same spatial frequency and orthogonal orientation, and (c) target embedded within a surrounding grating with parallel (same) orientation. Previous results with healthy populations have shown that contrast thresholds are lower for orthogonal and no-surround (NS) conditions than for parallel surround (PS). The log-ratios between parallel and NS thresholds are used as an index quantifying visual surround suppression. Patients performed poorly compared to controls in the NS and orthogonal-surround conditions. However, they performed as well as controls when the surround was parallel, resulting in significantly

  11. The Effect of Aging and Attention on Visual Crowding and Surround Suppression of Perceived Contrast Threshold.

    Science.gov (United States)

    Malavita, Menaka S; Vidyasagar, Trichur R; McKendrick, Allison M

    2017-02-01

    The purpose of this study was to study how, in midperipheral vision, aging affects visual processes that interfere with target detection (crowding and surround suppression) and to determine whether the performance on such tasks are related to visuospatial attention as measured by visual search. We investigated the effect of aging on crowding and suppression in detection of a target in peripheral vision, using different types of flanking stimuli. Both thresholds were also obtained while varying the position of the flanker (placed inside or outside of target, relative to fixation). Crowding thresholds were also estimated with spatial uncertainty (jitter). Additionally, we included a visual search task comprising Gabor stimuli to investigate whether performance is related to top-down attention. Twenty young adults (age, 18-32 years; mean age, 26.1 years; 10 males) and 19 older adults (age, 60-74 years; mean age, 70.3 years; 10 males) participated in the study. Older adults showed more surround suppression than the young (F[1,37] = 4.21; P attentional efficiency measured in the visual search task. There was also no significant correlation between crowding and surround suppression. We show that aging does not affect visual crowding but does increase surround suppression of contrast, suggesting that crowding and surround suppression may be distinct visual phenomena. Furthermore, strengths of crowding and surround suppression did not correlate with each other nor could they be predicted by efficiency of visual search.

  12. Study on the Optimal Equivalent Radius in Calculating the Heat Dissipation of Surrounding Rock

    Directory of Open Access Journals (Sweden)

    H. T. Song

    2015-11-01

    Full Text Available The heat dissipation of surrounding rock of a non-circular roadway is computed using an equivalent circular roadway approach under three circumstances when the area, perimeter, or hydraulic diameter of the circular roadway is equal to the non-circular roadway to obtain the optimal equivalent radius. The differential equations of heat conduction for unstable surrounding rock are established in cylindrical and rectangular coordinate systems using dimensionless analysis method. The calculation formulas of heat dissipation capacity and heat transfer resistance are derived from differential equations. Based on the method of equivalent radius, the similarities and differences between non-circular and circular roadways in calculating the heat dissipation of surrounding rock are discussed. Using the finite volume method, the calculation models for non-circular and circular roadways in the heat dissipation of surrounding rock are also established, among the non-circular roadways including three circumstances, namely, trapezoid, rectangle, and arch. The relation errors of heat dissipation of the surrounding rock of the three equivalent circular roadway methods are investigated for the three non-circular roadways. Results show that the calculation approach with equal perimeters is the best for the heat dissipation of surrounding rock of non-circular roadways.

  13. Damage to formation surrounding flooding wells: modelling of suspension filtration with account of particle trapping and mobilization

    Science.gov (United States)

    Boronin, S. A.; Tolmacheva, K. I.; Osiptsov, A. A.; Sitnikov, A. N.; Yakovlev, A. A.; Belozerov, B. V.; Belonogov, E. V.; Galeev, R. R.

    2017-11-01

    We consider the filtration of raw water in a formation surrounding injection wells in oilfields of Western Siberia. The mathematical model for suspension filtration developed earlier on the basis of tree-continua approach allows to describe the permeability damage and recovery due to trapping and mobilization of externally-introduced fines. As compared to classical deep-bed filtration models, the proposed model takes into account the filtration of the carrier fluid through the pack of trapped fines and uses only two free parameters to describe the particle trapping and mobilization rates. It has gone through a thorough validation campaign against experimental data with contamination of porous samples by external fines and mobilization of pre-seeded particles in sand packs. Simulations of permeability dynamics in the zone surrounding injection wells are carried out using the values of free parameters obtained by tuning the model against available lab experiments. Both continuous and periodic water flooding/cleanup is modelled. It is found that there are periodic regimes of water injection, in which the permeability of the rock is not damaged. The study will be continued after the calibration of the model against thorough laboratory tests with natural cores and field tests of injection rate dynamics in flooding wells.

  14. ZnO nanowires for the modification of evanescence-field sensors and the development of novel solar cells; ZnO-Nanodraehte zur Modifizierung von Evaneszenzfeldsensoren und der Entwicklung neuartiger Solarzellen

    Energy Technology Data Exchange (ETDEWEB)

    Boerner, Susanne

    2008-10-02

    The photoluminescence of single structures and the nanowire ensemble were analyzed and compared. This pursued in dependence on the excitation density and the sample temperature. The excitonic emission contributes essentially to the near-band-edge photoluminescence. The ZnO nanowire ensemble exhibits a laser threshold of 500 kW/cm{sup 2} at room temperature. To the photoluminescence spectra the single exciton processes were assigned. The wave-guiding properties were practically detected by means of optical microscopy and micromanipulation. While the main topic of this thesis lied in the analysis of the optical properties of the ZnO nanowires in the last part the implementation of nanostructures in hybrid solar cells was discussed and first results of the characterization of the material complex of p-conducting polymer (Clevios P) and ZnO nanowires presented.

  15. Purification of Body and Soul for the Next Journey. Practices Surrounding Death and Dying Among Muslim Women.

    Science.gov (United States)

    Ahaddour, Chaïma; Van den Branden, Stef; Broeckaert, Bert

    2017-01-01

    This study aims, first, to compare normative Islamic practices toward death and dying and actual practices of Moroccan Muslim women. Second, it seeks to compare the views and practices of middle-aged and elderly women. Qualitative empirical research was conducted with 30 middle-aged and elderly Moroccan Muslim women living in Antwerp (Belgium) and with 15 experts in the field. Our study shows that religious beliefs and worldview have a great impact on Muslims' practices surrounding death and dying. More specifically, practices are strongly shaped by their eschatological beliefs. The rituals are perceived as preparations for the hereafter, entailing purification of both soul and body, and demonstrate the belief in a continued existence of the soul. We found striking similarities between our participants' views and normative Islamic views. We did not find a more secular understanding of death and dying among the middle-aged women.

  16. Response Suppression in V1 Agrees with Psychophysics of Surround Masking

    Science.gov (United States)

    Zenger-Landolt, Barbara; Heeger, David J.

    2008-01-01

    When a target stimulus is embedded in a high contrast surround, the target appears reduced in contrast and is harder to detect, and neural responses in visual cortex are suppressed. We used functional magnetic resonance imaging (fMRI) and psychophysics to quantitatively compare these physiological and perceptual effects. Observers performed a contrast discrimination task on a contrast-reversing sinusoidal target grating. The target was either presented in isolation or embedded in a high-contrast surround. While observers performed the task, we also measured fMRI responses as a function of target contrast, both with and without a surround. We found that the surround substantially increased the psychophysical thresholds while reducing fMRI responses. The two data sets were compared, on the basis of the assumption that a fixed response difference is required for correct discrimination, and we found that the psychophysics accounted for 96.5% of the variance in the measured V1 responses. The suppression in visual areas V2 and V3 was stronger, too strong to agree with psychophysics. The good quantitative agreement between psychophysical thresholds and V1 responses suggests V1 as a plausible candidate for mediating surround masking. PMID:12890783

  17. Effects of Surrounding Information and Line Length on Text Comprehension from the Web

    Directory of Open Access Journals (Sweden)

    Jess McMullin

    2002-02-01

    Full Text Available The World Wide Web (Web is becoming a popular medium for transmission of information and online learning. We need to understand how people comprehend information from the Web to design Web sites that maximize the acquisition of information. We examined two features of Web page design that are easily modified by developers, namely line length and the amount of surrounding information, or whitespace. Undergraduate university student participants read text and answered comprehension questions on the Web. Comprehension was affected by whitespace; participants had better comprehension for information surrounded by whitespace than for information surrounded by meaningless information. Participants were not affected by line length. These findings demonstrate that reading from the Web is not the same as reading print and have implications for instructional Web design.

  18. The particulate environment surrounding the space station: Estimates from the PACS data

    Science.gov (United States)

    Green, Byron David

    1988-01-01

    The objectives of the Particle Analysis Cameras for Shuttle (PACS) experiment (flown on STS-61C) are described and the experiment results are discussed in reference to the expected Space Station environment. Estimates of the sources of particulates surrounding the Space Station were made based on the existing orbital observations data base. Particulates surrounding the shuttle are mostly event related or from the residual release of mass (dust) brought to orbit from the ground. The particulates surrounding the Space Station are likely to arise from additional sources such as operations, docking, erosion, and abrasion. Thus, scaling of the existing data base to long-duration missions in low-Earth orbit requires analysis, modeling, and simulation testing.

  19. Physical cell interactions with their surrounding materials: Mechanics and geometrical factors using microfluidic platforms

    Science.gov (United States)

    Lopez Garcia, Maria Del Carmen

    Microfluidics platforms are employed in: "sperm motion in a microfluidic device" and "mechanical interactions of mammary gland cells with their surrounding three dimensional extra-cellular matrix". Microfluidics has shown promise as a new platform for assisted reproduction. Sperm and fluid motion in microchannels was studied to understand the flow characteristics in the device, how sperm interacted with this flow, and how sperm-oocyte attachment occurs in the device. A threshold fluid velocity was found where sperm transition from traveling with the fluid to a regime in which they can move independently. A population of sperm remained in the inlet well area. There was also the tendency of sperm to travel along surface contours. These observations provide an improved understanding of sperm motion in microchannels and a basis for improved device designs. The effort to understand the development of breast cancer motivates the study of mammary gland cells and their interactions with the extra-cellular matrix. Mammographic density is a risk factor for breast cancer which correlates with collagen density affects cell behavior. Collagen gels with concentrations of 1.3, 2, and 3 mg/mL, were tensile tested to obtain the Young's modulus, E, at low displacement rates of 0.01, 0.1, and 1 mm/min. Local strain measurement in the gage section were used for both strain and strain rate determination. Local strain rates were on the order of cellular generated strain rate. A power law fitting described the relationship between Young's modulus and local strain rate. Mammary gland cells were seeded with collagen and fluorescent beads into microchannels and observed via four-dimensional imaging. The displacements of the beads were used to calculate strains. The Young's modulus due to the rate at which the cell was straining the collagen was obtained from the aforementioned fittings. Three-dimensional elastic theory for an isotropic material was employed to calculate the stress. The

  20. Vectorial near-field imaging of a GaN based photonic crystal cavity

    Energy Technology Data Exchange (ETDEWEB)

    La China, F., E-mail: lachina@lens.unifi.it; Intonti, F.; Caselli, N.; Lotti, F.; Vinattieri, A.; Gurioli, M. [European Laboratory for Non-linear Spectroscopy, 50019 Sesto Fiorentino (Italy); Department of Physics and Astronomy, University of Florence, 50019 Sesto Fiorentino (Italy); Vico Triviño, N.; Carlin, J.-F.; Butté, R.; Grandjean, N. [Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland)

    2015-09-07

    We report a full optical deep sub-wavelength imaging of the vectorial components of the electric local density of states for the confined modes of a modified GaN L3 photonic crystal nanocavity. The mode mapping is obtained with a scanning near-field optical microscope operating in a resonant forward scattering configuration, allowing the vectorial characterization of optical passive samples. The optical modes of the investigated cavity emerge as Fano resonances and can be probed without the need of embedded light emitters or evanescent light coupling into the nanocavity. The experimental maps, independently measured in the two in-plane polarizations, turn out to be in excellent agreement with numerical predictions.

  1. Cryogenic apparatus for study of near-field heat transfer.

    Science.gov (United States)

    Kralik, T; Hanzelka, P; Musilova, V; Srnka, A; Zobac, M

    2011-05-01

    For bodies spaced in vacuum at distances shorter than the wavelength of the thermal radiation, radiative heat transfer substantially increases due to the contribution of evanescent electromagnetic waves. Experimental data on heat transfer in near-field regime are scarce. We have designed a cryogenic apparatus for the study of heat transfer over microscopic distances between metallic and non-metallic surfaces. Using a mechanical positioning system, a planeparallel gap between the samples, concentric disks, each 35 mm in diameter, is set and varied from 10(0) to 10(3) μm. The heat transferred from the hot (10 - 100 K) to the cold sample (∼5 K) sinks into a liquid helium bath through a thermal resistor, serving as a heat flux meter. Transferred heat power within ∼2 nW∕cm(2) and ∼30 μW∕cm(2) is derived from the temperature drop along the thermal resistor. For tungsten samples, the distance of the near-field effect onset was inversely proportional to temperature and the heat power increase was observed up to three orders of magnitude greater than the power of far-field radiative heat transfer.

  2. Light distribution analysis of optical fibre probe-based near-field optical tweezers using FDTD

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B H; Yang, L J; Wang, Y [School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Heilongjiang, Harbin, 150001 (China)], E-mail: richelaw@163.com

    2009-09-01

    Optical fibre probe-based near-field optical tweezers overcomes the diffraction limit of conventional optical tweezers, utilizing strong mechanical forces and torque associated with highly enhanced electric fields to trap and manipulate nano-scale particles. Near-field evanescent wave generated at optical fibre probe decays rapidly with the distance that results a significant reduced trapping volume, thus it is necessary to analyze the near-field distribution of optical fibre probe. The finite difference time domain (FDTD) method is applied to characterize the near-field distribution of optical fibre probe. In terms of the distribution patterns, depolarization and polarization, the near-field distributions in longitudinal sections and cross-sections of tapered metal-coated optical fibre probe are calculated. The calculation results reveal that the incident polarized wave becomes depolarized after exiting from the nano-scale aperture of probe. The near-field distribution of the probe is unsymmetrical, and the near-field distribution in the cross-section vertical to the incident polarized wave is different from that in the cross-section parallel to the incident polarized wave. Moreover, the polarization of incident wave has a great impact on the light intensity distribution.

  3. Visual field

    Science.gov (United States)

    Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... Confrontation visual field exam. This is a quick and basic check of the visual field. The health care provider ...

  4. Spectroscopic study of the elusive globular cluster ESO452-SC11 and its surroundings

    Science.gov (United States)

    Koch, Andreas; Hansen, Camilla Juul; Kunder, Andrea

    2017-08-01

    Globular clusters (GCs) have long been recognized as being amongst the oldest objects in the Galaxy. As such, they have the potential of playing a pivotal role in deciphering the Milky Way's early history. Here we present the first spectroscopic study of the low-mass system ESO452-SC11 using the AAOmega multifibre spectrograph at medium resolution. Given the stellar sparsity of this object and the high degree of foreground contamination due to its location toward the Galactic bulge, very few details are known for this cluster - there is no consensus, for instance, about its age, metallicity, or its association with the disk or bulge. We identify five member candidates based on common radial velocity, calcium-triplet metallicity, and position within the GC. Using spectral synthesis, the measurement of accurate Fe-abundances from Fe-lines, and abundances of several α-, Fe-peak, and neutron-capture elements (Si, Ca, Ti,Cr, Co, Ni, Sr, and Eu) is carried out, albeit with large uncertainties. We find that two of the five cluster candidates are likely non-members, as they have deviating iron abundances and [α/Fe] ratios. The cluster mean heliocentric velocity is 19 ± 2 km s-1 with a velocity dispersion of 2.8 ± 3.4 km s-1, a low value in line with its sparse nature and low mass. The mean Fe-abundance from spectral fitting is -0.88 ± 0.03 dex, where the spread is driven by observational errors. Furthermore, the α-elements of the GC candidates are marginally lower than expected for the bulge at similar metallicities. As spectra of hundreds of stars were collected in a 2-degree field centered on ESO452-SC11, a detailed abundance study of the surrounding field was also enabled. The majority of the non-members have slightly higher [α/Fe] ratios, in line with the typical nearby bulge population. A subset of the spectra with measured Fe-peak abundance ratios shows a large scatter around solar values, albeit with large uncertainties. Furthermore, our study provides the

  5. Stratigraphy and tectonics of Permo-Triassic basins in the Netherlands and surrounding areas

    NARCIS (Netherlands)

    Geluk, M.C.

    2005-01-01

    This thesis addresses different aspects of the geological development during the Permian and Triassic (300 to 200 Ma) of the Netherlands and surrounding areas. The study area encompasses the Southern Permian Basin (SPB), a large intracratonic basin stretched out from the United Kingdom in the west

  6. Do personal conditions and circumstances surrounding partner loss explain loneliness in newly bereaved older adults?

    NARCIS (Netherlands)

    van Baarsen, B.; Smit, J.H.; Snijders, T.A.B.; Knipscheer, C.P.M.

    1999-01-01

    This longitudinal study aims to explain loneliness in newly bereaved older adults, taking into account personal and circumstantial conditions surrounding the partner's death. A distinction is made between emotional and social loneliness. Data were gathered both before and after partner loss. Results

  7. Numerical bifurcation analysis of distance-dependent on-center off-surround shunting neural networks.

    NARCIS (Netherlands)

    Molenaar, P.C.M.; Raijmakers, M.E.J.; van der Maas, H.L.J.

    1996-01-01

    On-center off-surround shunting neural networks are often applied as models for content-addressable memory (CAM), the equilibria being the stored memories. One important demand of biological plausible CAMs is that they function under a broad range of parameters, since several parameters vary due to

  8. Do personal conditions and circumstances surrounding partner loss explain loneliness in newly bereaved older adults?

    NARCIS (Netherlands)

    van Baarsen, B.; Smit, J.H; Snijders, T.A.B.; Knipscheer, K.P.M.

    This longitudinal study aims to explain loneliness in newly bereaved older adults, taking into account personal and circumstantial conditions surrounding the partner's death. A distinction is made between emotional and social loneliness. Data were gathered both before and after partner loss. Results

  9. Homogamy and Intermarriage of Japanese and Japanese Americans with Whites Surrounding World War II

    Science.gov (United States)

    Ono, Hiromi; Berg, Justin

    2010-01-01

    Although some sociologists have suggested that Japanese Americans quickly assimilated into mainstream America, scholars of Japanese America have highlighted the heightened exclusion that the group experienced. This study tracked historical shifts in the exclusion level of Japanese and Japanese Americans in the United States surrounding World War…

  10. Socio-economic impact of ox skidding project to the surrounding ...

    African Journals Online (AJOL)

    Results indicate that the ox skidding project has been a reliable and valuable source of income besides offering employment to young people with only limited ... in this area is likely to continue since farmers surrounding these plantations keep cattle and there are not many alternative job opportunities for the young people.

  11. Thermal and mechanical stability of retained austenite surrounded by martensite with different degrees of tempering

    NARCIS (Netherlands)

    Hidalgo Garcia, J.; Findley, K.O.; Santofimia Navarro, M.J.

    2017-01-01

    The mechanical and thermal stability of austenite in multiphase advanced high strength steels are influenced by the surrounding microstructure. The mechanisms underlying and the relations between thermal and mechanical stability are still dubious due to the difficulty of isolating other factors

  12. Can Centre Surround Model Explain the Enhancement of Visual Perception through Stochastic Resonance?

    CERN Document Server

    Kundu, Ajanta

    2010-01-01

    We demonstrate the ability of centre surround model for simulating the enhancement of contrast sensitivity through stochastic resonance observed in psychophysical experiments. We also show that this model could be used to simulate the contrast sensitivity function through stochastic resonance. The quality of the fit of measured contrast sensitivity function to the simulated data is very good.

  13. Evaluating the effect of the space surrounding the condenser of a household refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Bassiouny, Ramadan [Dept. of Mech. Power Eng. and Energy, Faculty of Engineering, Minia University, Minia 61111 (Egypt)

    2009-11-15

    The paper presents an analytical and computational modeling of the effect of the space surrounding the condenser of a household refrigerator on the rejected heat. The driving force for rejecting the heat carried by the refrigerant from the interior of a refrigerator is the temperature difference between the condenser outer surface and surrounding air. The variation of this difference, because of having an insufficient space, increasing the room air temperature, or blocking this space, is of interest to quantify its effect The results showed that having an enough surrounding space width (s > 200 mm) leads to a decrease in the temperature of the air flowing vertically around the condenser coil. Accordingly, this would significantly increase the amount of heat rejected. Moreover, blocking this space retards the buoyant flow up the condenser surface, and hence increases the air temperature around the condenser. This would also decrease the heat rejected from the condenser. Predicted temperature contours are displayed to visualize the air plumes' variation surrounding the condenser in all cases. (author)

  14. Evaluation of the impact of mine activity on surrounding soils of Draa ...

    African Journals Online (AJOL)

    Evaluation of the impact of mine activity on surrounding soils of Draa Lasfar mine in Marrakech- Morocco. ... African Journal of Environmental Science and Technology ... The aim of the present study was to evaluate the spatial distribution of heavy metals in Draa Lasfar mine area in Marrakech city and understand the ...

  15. The collective action on governing the commons in the surroundings of protected areas

    NARCIS (Netherlands)

    Araújo Pereira, de Márcio; Schneider, Sérgio; Ploeg, van der Jandouwe; Souza, de Marcelino

    2016-01-01

    This work has as its theme the common natural resources and the management models that allow new governance systems in the rural areas in the surrounding of protected areas. In this sense, this paper aims to discuss the collective action of social actors in the management of common natural

  16. Perils to pregnancies: On social sorrows and strategies surrounding pregnancy loss in Cameroon

    NARCIS (Netherlands)

    Sijpt, E. van der; Notermans, C.D.

    2010-01-01

    This article explores the local perceptions and practices surrounding pregnancy loss in Cameroon-a topic that has long been neglected in international reproductive health debates. Based on extended periods of anthropological fieldwork in an urban and a rural setting in the East province of the

  17. Greenhouse Effect: Temperature of a Metal Sphere Surrounded by a Glass Shell and Heated by Sunlight

    Science.gov (United States)

    Nguyen, Phuc H.; Matzner, Richard A.

    2012-01-01

    We study the greenhouse effect on a model satellite consisting of a tungsten sphere surrounded by a thin spherical, concentric glass shell, with a small gap between the sphere and the shell. The system sits in vacuum and is heated by sunlight incident along the "z"-axis. This development is a generalization of the simple treatment of the…

  18. Students' Inventory of Social Actors Concerned by the Controversy Surrounding Cellular Telephones: A Case Study

    Science.gov (United States)

    Pouliot, Chantal

    2008-01-01

    The present article scrutinizes the manner with which a group of three postsecondary students (in Quebec, Canada) describe the social actors concerned by the controversy surrounding cellular telephones. The study was conducted on the basis of an ethnographic approach. Participant observation was performed by the researcher for 3 hours during each…

  19. The aerodynamic effects of passing trains to surrounding objects and people

    Science.gov (United States)

    2009-04-01

    Two safety issues are raised on the aerodynamic effects of a passing train on its surroundings. First, a high-speed train passing other trains on an adjacent track exerts aerodynamic pressure that can affect the structural integrity of window mount a...

  20. Children's Perception of Surroundings in an Unfamiliar Environment

    Science.gov (United States)

    Hergan, Irena

    2018-01-01

    This article presents the results of research on how ten-year-old children in an unfamiliar environment perceive the surroundings of the route during their wayfinding when they focus on the task of successfully orienting themselves with two different sources of cartographic support: a mobile navigator and a paper map. The results show that the…

  1. Brief Report: Service Implementation and Maternal Distress Surrounding Evaluation Recommendations for Young Children Diagnosed with Autism

    Science.gov (United States)

    Warren, Zachary; Vehorn, Alison; Dohrmann, Elizabeth; Newsom, Cassandra; Taylor, Julie Lounds

    2013-01-01

    There is limited evidence surrounding the ability of families of children with autism spectrum disorders to access and implement recommended interventions following diagnosis. The distress a family may encounter with regard to inability to access recommended services is also poorly understood. In this study, we present preliminary data regarding…

  2. Gas Flux and Density Surrounding a Cylindrical Aperture in the Free Molecular Flow Regime

    Science.gov (United States)

    Soulas, George C.

    2011-01-01

    The equations for rigorously calculating the particle flux and density surrounding a cylindrical aperture in the free molecular flow regime are developed and presented. The fundamental equations for particle flux and density from a reservoir and a diffusely reflecting surface will initially be developed. Assumptions will include a Maxwell-Boltzmann speed distribution, equal particle and wall temperatures, and a linear flux distribution along the cylindrical aperture walls. With this information, the equations for axial flux and density surrounding a cylindrical aperture will be developed. The cylindrical aperture will be divided into multiple volumes and regions to rigorously determine the surrounding axial flux and density, and appropriate limits of integration will be determined. The results of these equations will then be evaluated. The linear wall flux distribution assumption will be assessed. The axial flux and density surrounding a cylindrical aperture with a thickness-to-radius ratio of 1.25 will be presented. Finally, the equations determined in this study will be verified using multiple methods.

  3. On the Optimal Radiation Bandwidth of Printed Slot Antennas Surrounded by EBGs

    NARCIS (Netherlands)

    Neto, A.; Llombart, N.; Gerini, G.; Maagt, P. de

    2006-01-01

    This paper describes a design strategy to achieve the maximum bandwidth and efficiency for a printed slot antenna surrounded by EBGs. First the dielectric constant and the thickness of the dielectric slab that guarantees an acceptable front to back radiation ratio is identified. Then electromagnetic

  4. Guest replacement in a flexible single-crystal host by mixing the surrounding gas.

    Science.gov (United States)

    Takamizawa, Satoshi; Miyake, Ryosuke

    2009-07-21

    The adsorption behavior of a single-crystal host [Cu2(bza)4(pyz)]n under vapor was studied by adsorption measurements and single-crystal X-ray analyses, demonstrating the sharp replacement of the included guest by mixing the surrounding vapor.

  5. Developmental Changes during Childhood in Single-Letter Acuity and Its Crowding by Surrounding Contours

    Science.gov (United States)

    Jeon, Seong Taek; Hamid, Joshua; Maurer, Daphne; Lewis, Terri L.

    2010-01-01

    Crowding refers to impaired target recognition caused by surrounding contours. We investigated the development of crowding in central vision by comparing single-letter and crowding thresholds in groups of 5-year-olds, 8-year-olds, 11-year-olds, and adults. The task was to discriminate the orientation of a Sloan letter E. Single-letter thresholds,…

  6. Climate change impacts on terrestrial ecosystems in metropolitan Chicago and its surrounding, multi-state region

    Science.gov (United States)

    Jessica J. Hellmann; Knute J. Nadelhoffer; Louis R. Iverson; Lewis H. Ziska; Stephen N. Matthews; Philip Myers; Anantha M. Prasad; Matthew P. Peters

    2010-01-01

    This paper describes the potential impacts of warming temperatures and changing precipitation on plants, wildlife, invasive species, pests, and agricultural ecosystems across the multi-state region centered on Chicago, Illinois. We examine a geographic area that captures much of Lake Michigan, including a complex mosaic of urbanization and agriculture surrounding...

  7. Difference of hydrological cycle between Islands and surrounding oceans over the Indonesian maritime continent

    Science.gov (United States)

    Kanamori, H.; Yasunari, T.

    2011-12-01

    The climate of the maritime continent is characterized by huge amounts of precipitation throughout the year and plays an essential role as a major atmospheric heat source of the Earth's climate system. The unique environment in this region with complex distribution of islands and warm pool favors the development of deep and frequent convection. The deep convection accompanied by heavy precipitation is generally observed over islands and its surrounding ocean rather than open seas. Major islands combined with surrounding warm seas, therefore, are most likely to play an important part in the energy and water cycle processes driving the complex atmospheric circulation pattern. To understand the time-space characteristics of the hydro-climate in Borneo, and its surrounding ocean, we examined the climatological hydrological cycle on monthly mean basis by using TRMM and JRA25/JCDAS reanalysis data from 1999-2010. The interactive nature between the hydro-climate and the tropical rainforest were also discussed. Seasonal variation of precipitation over Borneo and the surrounding ocean is very small compared with it in other tropics. The vertically- integrated moisture flux from surface to 100 hPa shows divergence throughout the year over the Borneo, suggesting that this island plays moisture source to atmosphere. In contrast, other major islands in the maritime continent, such as New Guina and Sumatra, seasonal cycle of the moisture flux convergence is clearly observed. The evapotranspiration, as defined by residual from precipitation and moisture flux convergence, contributes to precipitation over Borneo throughout the year. On the other hand, the contribution of moisture flux convergence for precipitation is noticeable over the surrounding ocean of Borneo, particularly during the boreal winter. The seasonal cycle of circulation pattern influences water budget over coastal area. These results strongly suggest that precipitation in the Borneo is basically occupied by

  8. Spontaneous magnetic alignment by yearling snapping turtles: rapid association of radio frequency dependent pattern of magnetic input with novel surroundings.

    Science.gov (United States)

    Landler, Lukas; Painter, Michael S; Youmans, Paul W; Hopkins, William A; Phillips, John B

    2015-01-01

    We investigated spontaneous magnetic alignment (SMA) by juvenile snapping turtles using exposure to low-level radio frequency (RF) fields at the Larmor frequency to help characterize the underlying sensory mechanism. Turtles, first introduced to the testing environment without the presence of RF aligned consistently towards magnetic north when subsequent magnetic testing conditions were also free of RF ('RF off → RF off'), but were disoriented when subsequently exposed to RF ('RF off → RF on'). In contrast, animals initially introduced to the testing environment with RF present were disoriented when tested without RF ('RF on → RF off'), but aligned towards magnetic south when tested with RF ('RF on → RF on'). Sensitivity of the SMA response of yearling turtles to RF is consistent with the involvement of a radical pair mechanism. Furthermore, the effect of RF appears to result from a change in the pattern of magnetic input, rather than elimination of magnetic input altogether, as proposed to explain similar effects in other systems/organisms. The findings show that turtles first exposed to a novel environment form a lasting association between the pattern of magnetic input and their surroundings. However, under natural conditions turtles would never experience a change in the pattern of magnetic input. Therefore, if turtles form a similar association of magnetic cues with the surroundings each time they encounter unfamiliar habitat, as seems likely, the same pattern of magnetic input would be associated with multiple sites/localities. This would be expected from a sensory input that functions as a global reference frame, helping to place multiple locales (i.e., multiple local landmark arrays) into register to form a global map of familiar space.

  9. Pattern of elevational distribution and richness of non volant mammals in Itatiaia National Park and its surroundings, in Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    L. Geise

    Full Text Available Itatiaia National Park (PNI and its surroundings present a unique fauna due to different forest formations with well-defined climatic and vegetation bands. The Itatiaia massif has four vegetation types that follow an altitudinal gradient: lower montane forest, montane forest, upper montane forest, and Campos de Altitude. Hence, this region is ideal for studying geographical variation in biological diversity. The main objectives of this study were to report on nonvolant mammal species known to occur in Itatiaia National Park and its surroundings and to determine if their distributional pattern is related to elevation. A review of the literature and a complete survey of specimens deposited in museums, as well as small-mammal trapping were carried out in order to obtain a complete record of the species from the region. Precise locality data were obtained for all specimens recorded, allowing the inclusion of each collected or observed individual in an altitude and vegetational class. We made a direct ordination gradient of marsupial, primate, and rodent species abundance with the altitude. Sixty-nine mammal species were collected or reported for the Itatiaia massif, belonging to seven orders and 20 families. Of these, 33 species (47.8% are included in the official list of threatened or believed-to-be threatened species in Rio de Janeiro State. The orders Rodentia, Carnivora, and Didelphimorphia had the highest species richness, with 25, 14, and 13 species respectively. When species were grouped according to the vegetation, 16 species occured in the lower montane, 56 in the montane forest, five in the upper montane, and 21 in the high-altitude fields (Campos de Altitude. The communities of marsupials, primates, and rodents have an ordination pattern related to the altitude. Species richness was higher between 500 m and 1,500 m above sea level in montane forest, which is in agreement with recent studies showing that species richness can reach its

  10. Field Plot Points for Badlands National Park Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This metadata is for the field data associated with the vegetation land cover and land use geospatial database for Badlands National Park and surrounding areas. The...

  11. Mode-locked silicon evanescent lasers

    National Research Council Canada - National Science Library

    Brian R. Koch; Alexander W. Fang; Oded Cohen; John E. Bowers

    2007-01-01

    .... The mode locked lasers generate 4 ps pulses with low jitter and extinction ratios above 18 dB, making them suitable for data and telecommunication transmitters and for clock generation and distribution...

  12. Planar Optical Sensors and Evanescent Wave Effects

    Science.gov (United States)

    Burke, Conor S.; Stránik, Ondrej; McEvoy, Helen M.; MacCraith, Brian D.

    Recent developments in microsystems technology have led to the widespread application of microfabrication techniques for the production of sensor platforms. These techniques have had a major impact on the development of so-called "Lab-on-a-Chip" devices. The major application areas for theses devices are biomedical diagnostics, industrial process monitoring, environmental monitoring, drug discovery, and defence. In the context of biomedical diagnostic applications, for example, such devices are intended to provide quantitative chemical or biochemical information on samples such as blood, sweat and saliva while using minimal sample volume.

  13. Evanescent Waveguide Sensors for Biomedical Applications

    NARCIS (Netherlands)

    Purniawan, A.

    2014-01-01

    The American Cancer Society reported that the major public health problem is cancer. Based on the report, colonic cancer is the major cancer type in the digestive system. In addition, the percentage of death rate due to this cancer is 50%. Surgery to remove the part of the colon infected by the

  14. Can texture of tissue surrounding microcalcifications in mammography be used for breast cancer diagnosis?

    Energy Technology Data Exchange (ETDEWEB)

    Karahaliou, A.; Boniatis, I.; Sakellaropoulos, P.; Skiadopoulos, S.; Panayiotakis, G. [Department of Medical Physics, School of Medicine, University of Patras, Patras 265 00 (Greece); Costaridou, L. [Department of Medical Physics, School of Medicine, University of Patras, Patras 265 00 (Greece)], E-mail: costarid@upatras.gr

    2007-10-01

    This study investigates whether texture properties of the tissue surrounding microcalcifications (MCs) can contribute to breast cancer diagnosis. A case sample of 100 MC clusters (46 benign, 54 malignant) from 85 dense mammographic images included in the Digital Database for Screening Mammography, is analyzed. Regions of interest containing clusters are processed using wavelet-based enhancement and individual MCs are segmented by local thresholding. The segmented MCs are removed from original image data and the surrounding tissue area is subjected to texture analysis. The feasibility of four texture feature sets (first-order statistics, gray level co-occurrence matrices, gray level run length matrices and Laws' texture energy measures) in discriminating malignant from benign tissue was investigated using a k-nearest neighbor classifier. Laws' texture energy measures achieved the best classification accuracy 89% (sensitivity 90.74% and specificity 86.96%)

  15. Stability Evaluation on Surrounding Rocks of Underground Powerhouse Based on Microseismic Monitoring

    Directory of Open Access Journals (Sweden)

    Feng Dai

    2015-01-01

    Full Text Available To study the stability of underground powerhouse at Houziyan hydropower station during excavation, a microseismic monitoring system is adopted. Based on the space-time distribution characteristics of microseismic events during excavation of the main powerhouse, the correlation between microseismic events and blasting construction is established; and the microseismic clustering areas of the underground powerhouse are identified and delineated. The FLAC3D code is used to simulate the deformation of main powerhouse. The simulated deformation characteristics are consistent with that recorded by microseismic monitoring. Finally, the correlation between the macroscopic deformation of surrounding rock mass and microseismic activities is also revealed. The results show that multiple faults between 1# and 3# bus tunnels are activated during excavation of floors V and VI of the main powerhouse. The comprehensive method combining microseismic monitoring with numerical simulation as well as routine monitoring can provide an effective way to evaluate the surrounding rock mass stability of underground caverns.

  16. Effects of fluorine emission on agricultural products surrounding an aluminum factory

    Energy Technology Data Exchange (ETDEWEB)

    Muramoto, S.; Nishizaki, H.; Aoyama, I. (Research Institute for Bioresources, Okayama University, Kurashiki (Japan))

    1991-06-01

    The F concentrations of precipitate dust, agricultural products, and fingernail and hair at the surrounding Al factory were investigated. The F content of dust ranged from 15400 to 42500 micrograms/g dry weight, 190,000 to 380,000 micrograms/g Al. Rice grain contained about 3.4 times more F than that in the control area, but some kinds of agricultural products, egg plants (S. melongena L.), mulberry plants (M. japonica Bailey non Sieb.), and soy beans (G. max (L.) Merrill) were almost equal to that of controls. Also, the high F concentration in the hair and nails of some workers was affected by available F contents in the emission from the factory as well as food and water surrounding the aluminum factory compared with those of control area.

  17. The Effects of GH Transgenic Goats on the Microflora of the Intestine, Feces and Surrounding Soil.

    Directory of Open Access Journals (Sweden)

    Zekun Bao

    Full Text Available The development of genetically engineered animals has brought with it increasing concerns about biosafety issues. We therefore evaluated the risks of growth hormone from transgenic goats, including the probability of horizontal gene transfer and the impact on the microbial community of the goats' gastrointestinal tracts, feces and the surrounding soil. The results showed that neither the GH nor the neoR gene could be detected in the samples. Moreover, there was no significant change in the microbial community of the gastrointestinal tracts, feces and soil, as tested with PCR-denaturing gradient gel electrophoresis and 16S rDNA sequencing. Finally, phylogenetic analysis showed that the intestinal content, feces and soil samples all contained the same dominant group of bacteria. These results demonstrated that expression of goat growth hormone in the mammary of GH transgenic goat does not influence the microflora of the intestine, feces and surrounding soil.

  18. Surrounding control of nonlinear multi-agent systems with non-identical agents.

    Science.gov (United States)

    Shoja, Shamisa; Baradarannia, Mahdi; Hashemzadeh, Farzad; Badamchizadeh, Mohammadali; Bagheri, Peyman

    2017-09-01

    In this paper, the surrounding control problem of a group of non-identical agents is considered, where a team of followers achieves an equidistant distributed formation to surround a team of moving leaders. An adaptive design method is presented for multi-agent systems where the dynamics of agents are supposed to be nonlinear with unknown parameters. First, an estimator for the center of the leaders is introduced. Then, two distributed adaptive controllers based on the estimated center are proposed for each follower. The stability and parameter convergence of the proposed protocols are shown by using algebraic graph theory and Lyapunov theory. Finally, a numerical example is provided to validate the theoretical results. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  19. The effect of wind direction and building surroundings on a marina bay in the Black Sea

    Science.gov (United States)

    Katona, Cosmin; Safta, Carmen Anca

    2017-01-01

    The wind effect has usually a major importance in the marina bay. These environmental sites are an interplay between tourist and commercial activities, requiring a high-detailed and definition studies of the dynamic fluid in the harbor. Computational Fluid Dynamics (CFD) has been used elaborately in urban surroundings research. However, most CFD studies were performed for harbors for only a confined number of wind directions and/or without considering the building surroundings effects. This paper presents the results of different simulations based on various wind flows and the CFD simulation of coupled urban wind flow and general wind directions upon a semi-closed area. Thus the importance of wind effects on the evaluation of the marina bay will be pointed out to achieve a safe and secure mooring at the berth and eventually a good potential of renewable energy for an impending green harbor.

  20. [Parasitic infections of coyote, Canis latrans (Carnivora: Canidae) in a Costa Rican National Park and a surrounding agricultural area].

    Science.gov (United States)

    Niehaus, Carmen; Valerio, Idalia; Blanco, Kinndle; Chinchilla, Misael

    2012-06-01

    As human populations expand into wild habitats with their pets and livestock, the potential spread of disease to wildlife or vice versa increases. Because, wild and domestic canids may pose as reservoirs or disseminators of infectious diseases (including parasites), coyotes (Canis latrans) may also serve as indicators of ecological health. In Costa Rica, little information exists on coyote parasites, making research necessary to identify potential zoonotic interactions. For this reason, a survey of the coyote parasites was performed in a mixed area of protected woodland and agricultural land, surrounding Irazú Volcano National Park (IVNP) in Cartago, Costa Rica. Over a one-year period, 209 fecal samples were collected directly from the ground. Collection took place on a monthly basis in a trail sectioned into three sub-areas named Irazú (closest to the volcano), potato fields (where potatoes were cultivated), and Prusia (a protected sector of IVNP). Sectioning the trail allowed separate collection and analysis of the samples, where 99 were obtained from Irazú, 11 from potato fields and 99 from Prusia. Using direct examination and mechanical concentration 36.84% positive samples containing at least one helminth were found. The presence of parasites was similar for both woodland areas (33.3% in Prusia and 37.4% in Irazú), but differed from the 63.6% observed in the potato fields. Hookworm parasites (probably Ancylostoma caninum), threadworms (possibly Strongyloides sp.), Toxocara canis, Trichuris sp. and Taenia pisiformis were identified, as well as Hymenolepis diminuta, possible spurious parasite resulting from the ingestion of rodents by coyotes. Seasonal details are discussed, concluding that wet and dry seasons affect presence of parasites. Some remarks are made on the importance of these first findings for Costa Rica, especially considering the systematic way in which the collection of samples was carried out.

  1. Systematic variation of population receptive field properties across cortical depth in human visual cortex

    NARCIS (Netherlands)

    Fracasso, Alessio; Petridou, N; Dumoulin, Serge O

    2016-01-01

    Receptive fields (RFs) in visual cortex are organized in antagonistic, center-surround, configurations. RF properties change systematically across eccentricity and between visual field maps. However, it is unknown how center-surround configurations are organized in human visual cortex across lamina.

  2. Perceived differences between natural and convolution reverberation types in 5.0 surround sound

    OpenAIRE

    Shriram, Alluri R.

    2011-01-01

    This Graduate Thesis investigates the perceived differences between natural and convolution reverberation in surround sound. Two spaces with distinct reverberation times were used for this study. Initially three musical excerpts from three instruments (Cello, Oboe, and Piano) were recorded in a dry studio environment. Then the Impulse Response (IR) of the spaces was captured using two methods: balloon burst and sine sweep. The dry excerpts were then recorded in the spaces to captu...

  3. Fat deposition surrounding intracerebral hemorrhage in a patient suffering from Zieve-syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Hilz, M.J.; Druschky, K.F.; Erbguth, F.; Huk, W.

    1989-03-01

    In a 42-year-old man, admitted a few hours after an acute cerebrovascular event, CT demonstrated a hyperdense hemorrhage surrounded by a hypodense rim similar to perifocal edema or liquefying blood, thus raising doubts about the acuteness of the event. Laboratory findings revealed Zieve-syndrome (alcoholic hyperlipemia, hemolytic anemia, and alcoholic fatty liver) and negative Hounsfield Unit measurement of the hypodense rim finally identified it as a layer of fat around the clot.

  4. Increased levels of oxidative and carbonyl stress markers in normal ovarian cortex surrounding endometriotic cysts.

    Science.gov (United States)

    Di Emidio, Giovanna; D'Alfonso, Angela; Leocata, Pietro; Parisse, Valentina; Di Fonso, Adina; Artini, Paolo Giovanni; Patacchiola, Felice; Tatone, Carla; Carta, Gaspare

    2014-11-01

    Many evidence support the view that endometriotic cyst may exert detrimental effect on the surrounding ovarian microenvironment so representing a risk to functionality of adjacent follicles. Patients with benign ovarian cyst (endometriotic, follicular and dermoid cysts) subjected to laparoscopic cystectomy were enrolled in the present retrospective study in order to analyze whether endometriotic tissue could negatively affect the surrounding normal ovarian cortex more severely than other ovarian cysts. To this end we carried out immunohistochemistry analysis and comparative determination of the transcription factor FOXO3A, oxidized DNA adduct 8-OHdG (8-hydroxy-2'-deoxyguanosine) and damaged proteins known as AGEs (Advanced Glycation End products) as markers of ovarian stress response and molecular damage. Our results show that all the markers analyzed were present in normal ovarian tissue surrounding benign cysts. We observed higher levels of FOXO3A (15.90 ± 0.28), 8-OHdG (13.33 ± 2.07) and AGEs (12.58 ± 4.34) staining in normal ovarian cortex surrounding endometriotic cysts in comparison with follicular cysts (9.04 ± 0.29, 2.67 ± 2.67, 11.31 ± 2.95, respectively) and dermoid cysts (2.02 ± 0.18, 4.33 ± 2.58 and 10.56 ± 4.03, respectively). These results provide evidence that ovarian endometrioma is responsible for more severe alterations to cellular biomolecules than follicular and dermoid cysts.

  5. A new compact subthreshold behavior model for dual-material surrounding gate (DMSG) MOSFETs

    Science.gov (United States)

    Chiang, T. K.

    2009-05-01

    On the basis of exact resultant solution of two-dimensional Poisson equation, a new compact subthreshold behavior model comprising two-dimensional potential, threshold voltage, subthreshold current and subthreshold swing for the dual-material surrounding gate (DMSG) MOSFETs is successfully developed. The model shows its validity by a good agreement with the simulated results from published device simulation software MEDICI. Besides offering the physical insight into device physics, the model provides the basic designing guidance for the DMSG MOSFETs.

  6. A moving line in the sand: a review of obstetric management surrounding periviability.

    Science.gov (United States)

    Arora, Kavita S; Miller, Emily S

    2014-06-01

    Periviable birth poses numerous clinical and ethical challenges for the practicing clinician. We review the data surrounding the administration of corticosteroids for fetal lung maturity, antibiotics in the case of preterm premature rupture of membranes, magnesium sulfate for cerebral palsy prophylaxis, fetal monitoring, and cesarean delivery. The ethical complexities of patient counseling are also reviewed with a recommendation toward shared decision making between patient and physician.

  7. Between Identity and Crisis : Discourse surrounding peace operations and reactions to discourse challenges

    OpenAIRE

    Hojem, Petter

    2010-01-01

    This thesis looks at how key actors hold certain expectations on how their country and its representatives should act, and that these expectations are formed on the basis of their collective foreign policy identity, which in turn is a product of historical and ideological experiences. More specifically the thesis looks at what discourses surrounds Sweden's participation in EU-led peace operations in Africa, and how key actors reacted to facts and information that challenge their expectations....

  8. The Nexus between Analyst Forecast Dispersion and Expected Returns Surrounding Stock Market Crashes

    Directory of Open Access Journals (Sweden)

    Terence Tai-Leung Chong

    2009-12-01

    Full Text Available The performance of analysts’ forecasts has attracted increasing attention in recent years. However, as yet, no empirical study has investigated the nexus between the analyst forecast dispersion (AFD and excess returns surrounding stock market crashes in any depth. This paper attempts to fill this void by estimating a Fama-French model regression with AFD as a factor. Instead of an expected linear relationship, a nonlinear U-shape relationship between the AFD and excess returns is found.

  9. MicroCT Bone Densitometry: Context Sensitivity, Beam Hardening Correction and the Effect of Surrounding Media

    Directory of Open Access Journals (Sweden)

    Philip L. Salmon

    2014-12-01

    Full Text Available The context-sensitivity of microCT bone densitometry due to beam hardening artefacts was assessed. Bones and teeth are scanned with varying thickness of surrounding media (water, alcohol, biological tissue and it is important to understand how this affects reconstructed attenuation (“density” of the mineralized tissue. Aluminium tubes and rods with thickness 0.127mm–5mm were scanned both in air or surrounded by up to 2cm of water. Scans were performed with different energy filters and degrees of software beam hardening correction (BHC. Also tested were the effects of signal-to-noise ratio, magnification and truncation. The thickness of an aluminium tube significantly affected its mean reconstructed attenuation. This effect of thickness could be reduced substantially by BHC for scans in air, but not for scans in water. Varying thickness of surrounding water also changed the mean attenuation of an aluminium tube. This artefact could be almost eliminated by an optimal BHC value. The “cupping” artefact of heterogeneous attenuation (elevated at outer surfaces could be corrected if aluminium was scanned in air, but in water BHC was much less effective. Scan truncation, changes to magnification and signal-to-noise ratio also caused artificial changes to measured attenuation. Measurement of bone mineral density by microCT is highly context sensitive. A surrounding layer of liquid or biological tissue reduces the ability of software BHC to remove bone density artefacts. Sample thickness, truncation, magnification and signal to noise ratio also affect reconstructed attenuation. Thus it is important for densitometry that sample and calibration phantom dimensions and mounting materials are standardised.

  10. DIDACTIC PROPOSAL FOR THE INTERPRETATION OF THE GEOGRAPHIC SPACE: THE CITY OF SEGOVIA AND ITS SURROUNDINGS

    Directory of Open Access Journals (Sweden)

    LUIS CARLOS MARTÍNEZ FERNÁNDEZ

    2015-12-01

    Full Text Available  PRESENTATION AND WORKING APPROACH This work is motivated by the interest in developing a useful tool for primary school teachers who want to innovate in the teaching of geography and their teaching methodology. From today’s perspective, didactics of the geography school is founded on the participation of children in the construction of their own knowledge and the acquisition of basic skills through interaction with the environment that surrounds them. 

  11. Impact of mechanical stretch on the cell behaviors of bone and surrounding tissues

    OpenAIRE

    Yu, Hye-Sun; Kim, Jung-Ju; Kim, Hae-Won; Lewis, Mark P; Wall, Ivan

    2016-01-01

    Mechanical loading is recognized to play an important role in regulating the behaviors of cells in bone and surrounding tissues in vivo. Many in vitro studies have been conducted to determine the effects of mechanical loading on individual cell types of the tissues. In this review, we focus specifically on the use of the Flexercell system as a tool for studying cellular responses to mechanical stretch. We assess the li...

  12. Influence of the personal and social surrounding on the tobacco consumption in Spanish adolescents

    Directory of Open Access Journals (Sweden)

    Blanca Martínez Abadía

    2010-03-01

    Full Text Available Tobacco addiction is the main problem of public health in the developed countries. The prevalence in our country is elevated among adolescent children and. The factors that influence in the acquisition and maintenance of the conduct to smoke are complex. Next to personal factors the importance of the personal and social surroundings of the adolescent is had underlining, the availability of this drug and the socioeconomic situation of the potentials consumers.

  13. Natural radionuclides in soil profiles surrounding the largest coal-fired power plant in Serbia

    OpenAIRE

    Tanić Milan N.; Janković-Mandić Ljiljana J.; Gajić Boško A.; Daković Marko Z.; Dragović Snežana D.; Bačić Goran G.

    2016-01-01

    This study evaluates the influence of the largest Serbian coal-fired power plant on radionuclide concentrations in soil profiles up to 50 cm in depth. Thirty soil profiles were sampled from the plant surroundings (up to 10 km distance) and analyzed using standard methods for soil physicochemical properties and gamma ray spectrometry for specific activities of natural radionuclides (40K, 226Ra and 232Th). Spatial and vertical distribution of radionuclides wa...

  14. Linking student performance in Massachusetts elementary schools with the "greenness" of school surroundings using remote sensing.

    Science.gov (United States)

    Wu, Chih-Da; McNeely, Eileen; Cedeño-Laurent, J G; Pan, Wen-Chi; Adamkiewicz, Gary; Dominici, Francesca; Lung, Shih-Chun Candice; Su, Huey-Jen; Spengler, John D

    2014-01-01

    Various studies have reported the physical and mental health benefits from exposure to "green" neighborhoods, such as proximity to neighborhoods with trees and vegetation. However, no studies have explicitly assessed the association between exposure to "green" surroundings and cognitive function in terms of student academic performance. This study investigated the association between the "greenness" of the area surrounding a Massachusetts public elementary school and the academic achievement of the school's student body based on standardized tests with an ecological setting. Researchers used the composite school-based performance scores generated by the Massachusetts Comprehensive Assessment System (MCAS) to measure the percentage of 3rd-grade students (the first year of standardized testing for 8-9 years-old children in public school), who scored "Above Proficient" (AP) in English and Mathematics tests (Note: Individual student scores are not publically available). The MCAS results are comparable year to year thanks to an equating process. Researchers included test results from 2006 through 2012 in 905 public schools and adjusted for differences between schools in the final analysis according to race, gender, English as a second language (proxy for ethnicity and language facility), parent income, student-teacher ratio, and school attendance. Surrounding greenness of each school was measured using satellite images converted into the Normalized Difference Vegetation Index (NDVI) in March, July and October of each year according to a 250-meter, 500-meter, 1,000-meter, and 2000-meter circular buffer around each school. Spatial Generalized Linear Mixed Models (GLMMs) estimated the impacts of surrounding greenness on school-based performance. Overall the study results supported a relationship between the "greenness" of the school area and the school-wide academic performance. Interestingly, the results showed a consistently positive significant association between the

  15. Surrounding greenness and exposure to air pollution during pregnancy: an analysis of personal monitoring data.

    Science.gov (United States)

    Dadvand, Payam; de Nazelle, Audrey; Triguero-Mas, Margarita; Schembari, Anna; Cirach, Marta; Amoly, Elmira; Figueras, Francesc; Basagaña, Xavier; Ostro, Bart; Nieuwenhuijsen, Mark

    2012-09-01

    Green spaces are reported to improve health status, including beneficial effects on pregnancy outcomes. Despite the suggestions of air pollution-related health benefits of green spaces, there is no available evidence on the impact of greenness on personal exposure to air pollution. We investigated the association between surrounding greenness and personal exposure to air pollution among pregnant women and to explore the potential mechanisms, if any, behind this association. In total, 65 rounds of sampling were carried out for 54 pregnant women who resided in Barcelona during 2008-2009. Each round consisted of a 2-day measurement of particulate matter with aerodynamic diameter ≤ 2.5 μm (PM₂.₅) and a 1-week measurement of nitric oxides collected simultaneously at both the personal and microenvironmental levels. The study participants were also asked to fill out a time-microenvironment-activity diary during the sampling period. We used satellite retrievals to determine the surrounding greenness as the average of Normalized Difference Vegetation Index (NDVI) in a buffer of 100 m around each maternal residential address. We estimated the impact of surrounding greenness on personal exposure levels, home-outdoor and home-indoor pollutant levels, and maternal time-activity. Higher residential surrounding greenness was associated with lower personal, home-indoor, and home-outdoor PM₂.₅ levels, and more time spent at home-outdoor. We found lower levels of personal exposure to air pollution among pregnant women residing in greener areas. This finding may be partly explained by lower home-indoor pollutant levels and more time spent in less polluted home-outdoor environment by pregnant women in greener areas.

  16. Production and zooplankton community structure in the lagoon and surrounding sea at Kavaratti atoll (Lakshadweep)

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    .6 degrees C, 35.7 x 10/3, ml.l/1 and 0.8, 1.5 and 3.6 mu g-at.l/1 respectively. Fluctuations in the secondary production were greater in the surrounding sea (19.9 to 44.8 mgC.m/2.d/1) than at lagoon (6.6 to 15.7 mgC.m/2 d/1). Zooplankton community structure...

  17. The analysis of creep characteristics of the surrounding rock of the carbonaceous rock tunnel based on Singh-Mitchell model

    Science.gov (United States)

    Luo, Junhui; Mi, Decai; Ye, Qiongyao; Deng, Shengqiang; Zeng, Fuquan; Zeng, Yongjun

    2018-01-01

    Carbonaceous rock has the characteristics of easy disintegration, softening, swelling and environmental sensitivity, which belongs to soft surrounding rock, and the deformation during excavation and long-term stability of the surrounding rock of carbonaceous rock tunnel are common problems in the construction of carbonaceous rock tunnel. According to the above, the Monitor and measure the displacement, temperature and osmotic pressure of the surrounding carbonaceous rock of the tunnel of Guangxi Hebai highway. Then it based on the obtaining data to study the creep mechanism of surrounding rock using Singh-Mitchell model and predict the deformation of surrounding rock before the tunnel is operation. The results show that the Singh-Mitchell creep model can effectively analyse and predict the deformation development law of surrounding rock of tunnel without considering temperature and osmotic pressure, it can provide reference for the construction of carbonaceous rock tunnel and the measures to prevent and reinforce it..

  18. Integrity of the hippocampus and surrounding white matter is correlated with language training success in aphasia.

    Science.gov (United States)

    Meinzer, Marcus; Mohammadi, Siawoosh; Kugel, Harald; Schiffbauer, Hagen; Flöel, Agnes; Albers, Johannes; Kramer, Kira; Menke, Ricarda; Baumgärtner, Annette; Knecht, Stefan; Breitenstein, Caterina; Deppe, Michael

    2010-10-15

    Aphasia after middle cerebral artery (MCA) stroke shows highly variable degrees of recovery. One possible explanation may be offered by the variability of the occlusion location. Branches from the proximal portion of the MCA often supply the mesial temporal lobe including parts of the hippocampus, a structure known to be involved in language learning. Therefore, we assessed whether language recovery in chronic aphasia is dependent on the proximity of the MCA infarct and correlated with the integrity of the hippocampus and its surrounding white matter. Language reacquisition capability was determined after 2weeks of intensive language therapy and 8months after treatment in ten chronic aphasia patients. Proximity of MCA occlusion relative to the internal carotid artery was determined by magnetic resonance imaging (MRI) based on the most proximal anatomical region infarcted. Structural damage to the hippocampus was assessed by MRI-based volumetry, regional microstructural integrity of hippocampus adjacent white matter by fractional anisotropy. Language learning success for trained materials was correlated with the proximity of MCA occlusion, microstructural integrity of the left hippocampus and its surrounding white matter, but not with lesion size, overall microstructural brain integrity and a control region outside of the MCA territory. No correlations were found for untrained language materials, underlining the specificity of our results for training-induced recovery. Our results suggest that intensive language therapy success in chronic aphasia after MCA stroke is critically dependent on damage to the hippocampus and its surrounding structures. Copyright 2010 Elsevier Inc. All rights reserved.

  19. Effects of surrounding land use on metal accumulation in environments and submerged plants in subtropical ponds.

    Science.gov (United States)

    Liu, Hui; Bu, Hongmei; Liu, Guihua; Wang, Zhixiu; Liu, Wenzhi

    2015-12-01

    Ponds are widely used as stormwater treatment facilities to retain contaminants, including metals, and to improve water quality throughout the world. However, there is still a limited understanding of the effects of surrounding land use on metal accumulation in pond environments and organisms. To address this gap, we measured the concentrations of nine metals (i.e., Al, Ba, Ca, K, Li, Mg, Na, Se, and Sr) in water, sediments, and submerged plants collected from 37 ponds with different surrounding land uses in southwestern China and assessed the metal accumulation capacity of four dominant submerged plant species. Our results showed that Al, Ca, and K concentrations in the water were above drinking water standards. In the sediments, the average concentrations of Ca and Sr were higher than the corresponding soil background values. Ceratophyllum demersum L. could accumulate more K in aboveground biomass than Myriophyllum spicatum L. and Potamogeton maackianus A. Benn. The K concentration in submerged plants was positively influenced by the corresponding metal concentration in the water and negatively influenced by water temperature. Among the nine studied metals, only the water K concentration in ponds receiving agricultural runoff was significantly higher than that for ponds receiving urban and forested runoff. This result suggests that surrounding land use types have no significant effect on metal accumulation in sediments and submerged plants in the studied ponds. A large percentage of the metals in these ponds may be derived from natural sources such as the weathering of rocks.

  20. Human ovarian tissue from cortex surrounding benign cysts: a model to study ovarian tissue cryopreservation.

    Science.gov (United States)

    Schubert, Benoît; Canis, Michel; Darcha, Claude; Artonne, Christine; Pouly, Jean-Luc; Déchelotte, Pierre; Boucher, Daniel; Grizard, Geneviève

    2005-07-01

    The scarcity of human ovarian tissue is a major problem in developing research on ovarian cryopreservation. We were interested in ovarian cortex surrounding benign ovarian cysts harvested during their requisite operations. Ovarian tissue was collected from 25 women (mean age = 27.7 +/- 1.0 SEM) and frozen in serum-free cryoprotective medium. Histological and viability analysis were performed on fresh and frozen-thawed slices of tissue. Dermoid (n = 7), endometriosis (n = 13) and serous (n = 5) cysts were observed. Follicular densities (expressed per mm3) in ovarian cortex surrounding dermoid cysts were higher than in endometriosis and serous cysts for both histological (median of follicular densities: 13.04, 0.31 and 0.89 respectively) and viability analysis (2.93, 0.05 and 0.71 respectively). Freezing-thawing did not result in gross abnormality of follicle population either in number or morphology (80% of follicles preserved a normal pattern). However, a slight decrease of the density of living follicles (expressed per mm2) was reported. Ovarian cortex surrounding ovarian cysts, especially dermoid cysts, could be considered a source of ovarian tissue for future research. In our study, the cryopreservation procedure resulted in high follicular survival assessed by both histological and viability analysis. Nevertheless, further studies of in vivo and in vitro follicular maturation are needed to strengthen this model.

  1. INTERACTION OF A LONG PILE OF FINITE STIFFNESS WITH SURROUNDING SOIL AND FOUNDATION CAP

    Directory of Open Access Journals (Sweden)

    Ter-Martirosyan Zaven Grigor’evich

    2015-09-01

    Full Text Available The article presents the formulation and analytical solution to a quantification of stress strain state of a two-layer soil cylinder enclosing a long pile, interacting with the cap. The solution of the problem is considered for two cases: with and without account for the settlement of the heel and the underlying soil. In the first case, the article is offering equations for determining the stresses of pile’s body and the surrounding soil according to their hardness and the ratio of radiuses of the pile and the surrounding soil cylinder, as well as formulating for determining equivalent deformation modulus of the system “cap-pile-surrounding soil” (the system. Assessing the carrying capacity of the soil under pile’s heel is of great necessity. In the second case, the article is solving a second-order differential equation. We gave the formulas for determining the stresses of the pile at its top and heel, as well as the variation of stresses along the pile’s body. The article is also formulating for determining the settlement of the foundation cap and equivalent deformation modulus of the system. It is shown that, pushing the pile into underlying layer results in the reducing of equivalent modulus of the system.

  2. Biogeography of Timor and Surrounding Wallacean Islands: Endemism in Ants of the Genus Polyrhachis Fr. Smith

    Directory of Open Access Journals (Sweden)

    Colin R. Trainor

    2013-03-01

    Full Text Available The Wallacean island of Timor is of particular biological interest due to its relatively large size and transitional location between the Indo-Malayan and Australasian biogeographic realms. However, the origins and levels of endemism of its invertebrate fauna are poorly known. A recent study of Timorese ants revealed a diverse fauna with predominantly Indo-Malayan affinities, but species-level taxonomy was considered to be too poorly understood for an analysis of levels of endemism. The highly diverse Old World tropical genus Polyrhachis represents a notable exception, and here we analyse levels of endemism in the Polyrhachis fauna of Timor and surrounding islands. We supplement the species listed in the previous study with additional collections to record a total of 35 species of Polyrhachis from Timor and surrounding islands. Only 14 (40% of the 35 species could be named (P. constricta, P. costulata, P. gab, P. sokolova, P. hera, P. illaudata, P. rixosa, P. acantha chrysophanes, P. saevissima, P. bicolor, P. cryptoceroides, P. dives, P. longipes and P. olybria, and the large majority of the remaining species have not previously been collected. These are very likely to be endemic to Timor and surrounding islands, and point to remarkably high levels (>50% of endemism in the regional ant fauna.

  3. Virtual AM Stereo and Surround Sound to setup AM/FM Radio Theatre

    Directory of Open Access Journals (Sweden)

    Selvakumaran Vadivelmurugan

    2003-08-01

    Full Text Available Introduction of virtual surround sound and stereo to AM radio has been proposed in this study. This technology can be further applied to aid the construction of an AM radio theatre. Adding to the advantages of AM, the lower bandwidth, higher range and simpler circuitry, AM can now offer excellent sound effect with the post-transmission process. The motivation for the introduction of virtual surround sound is the poor quality of AM sound. In this study, the response by human ear has been thoroughly investigated and the methodology to create virtual surround sound has been developed. The elements essential to setup audio theatre such as the components of audio chain, multiple unit audio speaker, inner section of the ear, psychological effect of different ranges of frequency and radio theatre design have been extensively studied on the basis of Helmholtz audition theory. The vital changes include the different frequency division multiplexing of message at the transmitting end, three phases of the process, resulting in the vertical and horizontal digital connection, espresso program and the 3x12 speaker design theatre.

  4. Determination of the chemical composition of human renal stones with MDCT: influence of the surrounding media

    Science.gov (United States)

    Grosjean, Romain; Sauer, Benoît; Guerra, Rui; Kermarrec, Isabelle; Ponvianne, Yannick; Winninger, Daniel; Daudon, Michel; Blum, Alain; Felblinger, Jacques; Hubert, Jacques

    2007-03-01

    The selection of the optimal treatment method for urinary stones diseases depends on the chemical composition of the stone and its corresponding fragility. MDCT has become the most used modality to determine rapidly and accurately the presence of stones when evaluating urinary lithiasis treatment. That is why several studies have tempted to determine the chemical composition of the stones based on the stone X-ray attenuation in-vitro and invivo. However, in-vitro studies did not reproduce the normal abdominal wall and fat, making uncertain the standardization of the obtained values. The aim of this study is to obtain X-ray attenuation values (in Hounsfield Units) of the six more frequent types of human renal stones (n=217) and to analyze the influence of the surrounding media on these values. The stones were first placed in a jelly, which X-ray attenuation is similar to that of the human kidney (30 HU at 120 kV). They were then stuck on a grid, scanned in a water tank and finally scanned in the air. Significant differences in CT-attenuation values were obtained with the three different surrounding media (jelly, water, air). Furthermore there was an influence of the surrounding media and consequently discrepancies in determination of the chemical composition of the renal stones. Consequently, CT-attenuation values found in in-vitro studies cannot really be considered as a reference for the determination of the chemical composition except if the used phantom is an anthropomorphic one.

  5. Combined Visibility and Surrounding Triangles Method for Simulation of Crack Discontinuities in Meshless Methods

    Directory of Open Access Journals (Sweden)

    H. Pirali

    2012-01-01

    Full Text Available In this paper a combined node searching algorithm for simulation of crack discontinuities in meshless methods called combined visibility and surrounding triangles (CVT is proposed. The element free Galerkin (EFG method is employed for stress analysis of cracked bodies. The proposed node searching algorithm is based on the combination of surrounding triangles and visibility methods; the surrounding triangles method is used for support domains of nodes and quadrature points generated at the vicinity of crack faces and the visibility method is used for points located on the crack faces. In comparison with the conventional methods, such as the visibility, the transparency, and the diffraction method, this method is simpler with reasonable efficiency. To show the performance of this method, linear elastic fracture mechanics analyses are performed on number of standard test specimens and stress intensity factors are calculated. It is shown that the results are in good agreement with the exact solution and with those generated by the finite element method (FEM.

  6. Cadmium triggers Elodea canadensis to change the surrounding water pH and thereby Cd uptake.

    Science.gov (United States)

    Javed, M Tariq; Greger, Maria

    2011-01-01

    This study was aimed to investigate the influence of Elodea canadensis shoots on surrounding water pH in the presence of cadmium and the effect of plant-induced pH on cadmium uptake. The pH change in the surrounding nutrient solution and Cd uptake by Elodea shoots were investigated after cultivation of various plant densities (1, 3, 6 plants per 500 ml) in hydroponics at a starting pH of 4.0 and in the presence of different concentrations of cadmium (0, 0.1, 0.5 microM). Cadmium uptake was also investigated at different constant pH (4.0, 4.5, 5.5 and 6.5). To investigate if the pH change arose from photosynthetic activities, plants were grown under light, darkness or in the presence of a photosynthetic inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and 0.5 microM cadmium in the solution. Elodea had an ability to increase the surrounding water pH, when the initial pH was low, which resulted in increased accumulation of Cd. The higher the plant density, the more pronounced was the pH change. The pH increase was not due to the photosynthetic activity since the pH rise was more pronounced under darkness and in the presence of DCMU. The pH increase by Elodea was triggered by cadmium.

  7. [Diversity of crenarchaeota in terrestrial hot springs and their surrounding environments in Kamchatka, Russia].

    Science.gov (United States)

    Song, Zhaoqi; Wang, Li; Chen, Jinquan; Zhou, Enmin; Zhang, Chuanlun; Li, Wenjun

    2013-06-04

    Crenarchaeota is a major archaeal lineage in terrestrial hot springs and important in biogeochemical cycles of life-essential elements. In this study, we investigated the diversity of Crenarchaeota in hot springs and the surrounding environments in Kamchatka, Russia. In addition, we compared crenarchaeotal community structures in Kamchatka, Russia and Yunnan province, China. Crenarchaeal 16S rRNA gene clone libraries were constructed and the sequences and abundances of representational clone were obtained. Phylogenetic analysis was then performed and the community structures in different samples were compared. The high temperature spring Burlyashi Liza (BSL, 89 degrees C) comprised Thermoprotei. The moderate temperature spring TF Vent 2 (TFV, 49 degrees C) harbored unidentified Thermoprotei group, unidentified crenarchaeal group, HWCG-II (hot water crenarchaeotal group II), and Group1. 1b (one thaumarchaeotal subgroup). Most of sequences that obtained from surrounding environments ( Crenarchaeota in Kamchatka hot springs are somewhat different from those in Yunnan province. Terrestrial hot springs obviously affect the crenarchaeotal communities in surrounding environments. Temperature is the major factor controlling the community structure in terrestrial hot springs.

  8. Lead identification in soil surrounding a used lead acid battery smelter area in Banten, Indonesia

    Science.gov (United States)

    Adventini, N.; Santoso, M.; Lestiani, D. D.; Syahfitri, W. Y. N.; Rixson, L.

    2017-06-01

    A used lead acid battery smelter generates particulates containing lead that can contaminate the surrounding environment area. Lead is a heavy metal which is harmful to health if it enters the human body through soil, air, or water. An identification of lead in soil samples surrounding formal and informal used lead acid battery smelters area in Banten, Indonesia using EDXRF has been carried out. The EDXRF accuracy and precision evaluated from marine sediment IAEA 457 gave a good agreement to the certified value. A number of 16 soil samples from formal and informal areas and 2 soil samples from control area were taken from surface and subsurface soils. The highest lead concentrations from both lead smelter were approximately 9 folds and 11 folds higher than the reference and control samples. The assessment of lead contamination in soils described in Cf index was in category: moderately and strongly polluted by lead for formal and informal lead smelter. Daily lead intake of children in this study from all sites had exceeded the recommended dietary allowance. The HI values for adults and children living near both lead smelter areas were greater than the value of safety threshold 1. This study finding confirmed that there is a potential health risk for inhabitants surrounding the used lead acid battery smelter areas in Banten, Indonesia.

  9. Symptoms and Cognitive Effects of Exposure to Magnetic Stray Fields of MRI Scanners

    NARCIS (Netherlands)

    Vocht, Frank Gérard de

    2006-01-01

    People working routinely with magnetic resonance imaging (MRI) systems report a number of symptoms related to their presence in the inhomogeneous static magnetic fields (the stray field) surrounding these scanners. Experienced symptoms and neurobehavioral performance among engineers manufacturing

  10. The Process Of Disclosing A Gays Personal Status To His Surrounding In Medan North Sumatera Province Indonesia A Study On Interpersonal Communication By Using Self-Disclosure Approach

    Directory of Open Access Journals (Sweden)

    Dwianita

    2017-06-01

    Full Text Available The title of the research was The Process of Disclosing A Gays Personal Status to His Surroundings in Medan North Sumatera Province Indonesia A Study on Interpersonal Communication by Using Self-Disclosure Approach. The purpose of this research was to find out the process of self-disclosure of gays to family friends and his surrounding about his status as gay. The method used is descriptive research method qualitative approach. Theories used are Inter-Personal Communication Self Disclosure Social Penetration Theory. Data collection technique is done by in depth interview with a gay and added with archives and documentation. Stages of data processing starting from field research and library research. Through this study found that there are differences in the process of gay self-disclosure in the family and friends. Self-disclosure begins with gay acceptance of how he can accept his sexual orientation as a gay. After being able to accept his condition he then discloses himself in a different way to his family friends and his surrounding. There are also obstacles experienced in self-disclosure to the family namely the fear of disappointing the family.

  11. Tobacco retailer density surrounding schools and youth smoking behaviour: a multi-level analysis

    Directory of Open Access Journals (Sweden)

    Leatherdale Scott T

    2011-07-01

    Full Text Available Abstract Background Youth smoking prevention should be a public health priority. It is not only vital to prevent youth from smoking but also to prevent non-smoking youth from becoming susceptible to smoking. Past research has examined factors associated with youth's susceptibility to become a future smoker, but research has yet to examine tobacco retailer density and susceptibility to smoking among never smokers. The objectives of this study are to examine how tobacco retailer density surrounding schools and social smoking influences are associated with smoking susceptibility among youth of never smokers, and occasional and daily smoking among youth of current smokers. Methods Data were collected in 2005-2006 from grade 9 to 12 students attending 76 secondary schools in Ontario, Canada, as part of the SHAPES-On study. A series of multi-level logistic regression analyses were performed to understand how student- and school-level factors are associated with three smoking behaviour outcomes: smoking susceptibility among never smokers, occasional smoking, and daily smoking. Results The number of tobacco retailers surrounding a school was found to be associated with the likelihood of a never smoker being susceptible to future smoking (OR 1.03, 95CI% 1.01, 1.05. We also identified that being surrounded by smoking social influences, specifically family and close friends, can substantially increase the likelihood that never smokers are at risk for future smoking or that youth are already occasional or daily smokers. Conclusions We identified that the number of tobacco retailers surrounding a school was associated with an increased odds of being susceptible to future smoking among male never smokers. Smoking social models surrounding youth also appears to have an important impact on their smoking behaviour regardless of their smoking status. It is important for youth smoking prevention programs to begin early, interrupt youths' susceptibility to future

  12. Changing carbonate chemistry in ocean waters surrounding coral reefs in the CMIP5 ensemble

    Science.gov (United States)

    Ricke, K.; Schneider, K.; Cao, L.; Caldeira, K.

    2012-12-01

    Coral reefs comprise some of the most biodiverse ecosystems in the world. Today they are threatened by a number of stressors, including pollution, bleaching from global warming and ocean acidification. In this study, we focus on the implications of ocean acidification for the open ocean chemistry surrounding coral reefs. We use results from 13 Earth System Models included in the Coupled Model Intercomparison Project 5 (CMIP5) to examine the changing aragonite saturations (Ωa) of open ocean waters surrounding approximately 6,000 coral reefs. These 13 Earth System Models participating in CMIP5 each have interactive ocean biogeochemistry models that output state variables including DIC, alkalinity, SST, and salinity. Variation in these values were combined with values from the GLODAP database to calculate aragonite, the form of calcium carbonate that corals use to make their skeletons. We used reef locations from ReefBase that were within one degree (in latitude or longitude) of water masses represented both in the GLODAP database and in the climate models. Carbonate chemistry calculations were performed by Dr. James C. Orr (IPSL) as part of a separate study. We find that in preindustrial times, 99.9 % of coral reefs were located in regions of the ocean with aragonite saturations of 3.5 or more. The saturation threshold for viable reef ecosystems in uncertain, but the pre-industrial distribution of water chemistry surrounding coral reefs may nevertheless provide some indication of viability. We examine the fate of coral reefs in the context of several potential aragonite saturation thresholds, i.e., when Ωa_crit equals 3, 3.25, or 3.5. We show that under a business-as-usual scenario Representative Concentration Pathway (RCP) 8.5, the specific value of Ωa_crit does not affect the long-term fate of coral reefs -- by the end of the 21st century, no coral reef considered is surrounded by water with Ωa> 3. However, under scenarios with significant CO2 emissions

  13. Disparities in the food environment surrounding US middle and high schools.

    Science.gov (United States)

    Sturm, Roland

    2008-07-01

    Disparities in the type and density of food retail outlets have been hypothesized as a possible cause of differential obesity rates across racial/ethnic and income groups. Several local studies have documented differences in business environments by sociodemographic neighbourhood characteristics, but no data specific for youth have been published. This study analyses the food environment surrounding all public middle and high schools in the USA. Buffers were calculated with a radius of 400 and 800 m from the main entrance of public secondary schools in the USA (n=31,622), and business establishments within those buffers were identified using InfoUSA proprietary business listings. Indicators of any convenience store, limited-service restaurant, snack store or off-licences/liquor store and counts of businesses were regressed on the proportion of students eligible for free school meals, Title I eligibility of the school, racial/ethnic composition, location and student/teacher ratio. Hispanic youth are particularly likely to attend schools that are surrounded by convenience stores, restaurants, snack stores or off-licences. This effect is independent and in addition to poverty (i.e. students eligible for free school meals or schools that are Title I eligible) or location (urban core, suburban, town, rural). The association between other racial groups and nearby businesses is weaker, with the exception of off-licences, where a higher proportion of minority groups increases the probability of off-licences in close proximity to the school. Middle schools have fewer surrounding businesses than high schools, and larger schools have fewer surrounding businesses than smaller schools. Easy availability of snacks, sodas and fast food in the immediate vicinity of a school could easily negate school food policies, especially among students who can leave campus. Surrounding food outlets could also lower the effectiveness of health education in the classroom by setting a highly

  14. Mixed Rabi Jaynes-Cummings model of a three-level atom interacting with two quantized fields

    Science.gov (United States)

    Torosov, Boyan T.; Longhi, Stefano; Della Valle, Giuseppe

    2015-07-01

    The quantum Rabi model describes the ultrastrong interaction of a two-level atom coupled to a single quantized bosonic mode. As compared to the Jaynes-Cummings model, in the Rabi model the absorption and emission processes do not need to satisfy energy conservation and the usual rotating wave approximation (RWA) breaks down. As a result, the atom-field dynamics in the Hilbert space splits into two independent parity chains, exhibiting a collapse-revival pattern and exact periodic dynamics in the limit of degenerate atomic levels. Here we introduce a mixed Rabi Jaynes-Cummings model by considering a three-level atom interacting with two quantized bosonic fields, in which the RWA is made for one transition (with a weak atom-field coupling) but not for the other one (with an ultrastrong atom-field coupling). As a result, we show that the field in the weak coupled atomic transition can be used as a tool to control the atom-field dynamics of the other (strong coupled) transition, thus realizing an effective two-level quantum Rabi model with a controllable field. In particular, a periodic temporal dynamics of the atom-field state can be realized by appropriate tuning of the weak control field, even for non-degenerate atomic levels. A photonic simulator of the mixed Rabi Jaynes-Cummings model, based on light transport in evanescently coupled optical waveguide lattices, is also briefly discussed.

  15. Phase Field

    Science.gov (United States)

    Koyama, Toshiyuki

    The term phase field has recently become known across many fields of materials science. The meaning of phase field is the spatial and temporal order parameter field defined in a continuum-diffused interface model. By using the phase field order parameters, many types of complex microstructure changes observed in materials science are described effectively. This methodology has been referred to as the phase field method, phase field simulation, phase field modeling, phase field approach, etc. In this chapter, the basic concept and theoretical background for the phase field approach is explained in Sects. 21.1 and 21.2. The overview of recent applications of the phase field method is demonstrated in Sects. 21.3 to 21.6.

  16. Study on the Reinforcement Measures and Control Effect of the Surrounding Rock Stability Based on the Shield Tunneling Under Overpass Structure

    Directory of Open Access Journals (Sweden)

    Qian-cheng Fang

    2016-04-01

    Full Text Available To study the stability of surrounding rocks for shield tunneling under overpass structures and the safety of existing bridge structures, a practical example of the method was cited through a shield tunneling project under the overpass structure between K1+110 and K1+700 on Line 2 of Shenyang Subway, China. The sub-area reinforcement was proposed according to surrounding rock deformation characteristics during shield tunnel excavation. The bridge foundation (i.e., the clear spacing to the shield tunnel is less than 2 m was reinforced by steel support, the bridge foundation (the clear spacing is about 2~7m used “jet grouting pile” reinforcement, whereas the bridge foundation (the clear spacing is greater than 7 m did not adopt any reinforcement measures for the moment. For this study, the mean value and material heterogeneity models were established to evaluate the reinforcement effect from several aspects, such as surrounding rock deformation, plastic zone development, and safety factor. The simulation results were consistent with those of field monitoring. After reinforcement, the maximum deformation values of the surrounding rock were reduced by 4.9%, 12.2%, and 48.46%, and the maximum values of surface subsidence were decreased by 5.6%, 72.2%, and 88.64%. By contrast, the overall safety factor was increased by 4.1%, 55.46%, and 55.46%. This study posited that this reinforcement method can be adopted to solve tunnel construction problems in engineering-geological conditions effectively. References for evaluating similar projects are provided.

  17. Practical system for recording spatially lifelike 5.1 surround sound and 3D fully periphonic reproduction

    Science.gov (United States)

    Miller, Robert E. (Robin)

    2005-04-01

    In acoustic spaces that are played as extensions of musical instruments, tonality is a major contributor to the experience of reality. Tonality is described as a process of integration in our consciousness over the reverberation time of the room of many sonic arrivals in three dimensions, each directionally coded in a learned response by the listeners unique head-related transfer function (HRTF). Preserving this complex 3D directionality is key to lifelike reproduction of a recording. Conventional techniques such as stereo or 5.1-channel surround sound position the listener at the apex of a triangle or the center of a circle, not the center of the sphere of lifelike hearing. A periphonic reproduction system for music and movie entertainment, Virtual Reality, and Training Simulation termed PerAmbio 3D/2D (Pat. pending) is described in theory and subjective tests that capture the 3D sound field with a microphone array and transform the periphonic signals into ordinary 6-channel media for either decoderless 2D replay on 5.1 systems, or lossless 3D replay with decoder and five additional speakers. PerAmbio 3D/2D is described as a practical approach to preserving the spatial perception of reality, where the listening room and speakers disappear, leaving the acoustical impression of the original venue.

  18. Analysis of current density and specific absorption rate in biological tissue surrounding transcutaneous transformer for an artificial heart.

    Science.gov (United States)

    Shiba, Kenji; Nukaya, Masayuki; Tsuji, Toshio; Koshiji, Kohji

    2008-01-01

    This paper reports on the current density and specific absorption rate (SAR) analysis of biological tissue surrounding an air-core transcutaneous transformer for an artificial heart. The electromagnetic field in the biological tissue is analyzed by the transmission line modeling method, and the current density and SAR as a function of frequency, output voltage, output power, and coil dimension are calculated. The biological tissue of the model has three layers including the skin, fat, and muscle. The results of simulation analysis show SARs to be very small at any given transmission conditions, about 2-14 mW/kg, compared to the basic restrictions of the International Commission on nonionizing radiation protection (ICNIRP; 2 W/kg), while the current density divided by the ICNIRP's basic restrictions gets smaller as the frequency rises and the output voltage falls. It is possible to transfer energy below the ICNIRP's basic restrictions when the frequency is over 250 kHz and the output voltage is under 24 V. Also, the parts of the biological tissue that maximized the current density differ by frequencies; in the low frequency is muscle and in the high frequency is skin. The boundary is in the vicinity of the frequency 600-1000 kHz.

  19. Prototypical components of honeybee homing flight behaviour depend on the visual appearance of objects surrounding the goal

    Directory of Open Access Journals (Sweden)

    Elke eBraun

    2012-01-01

    Full Text Available Honeybees use visual cues to relocate profitable food sources and their hive. What bees see while navigating, depends on the appearance of the cues, the bee’s current position, orientation and movement relative to them. Here we analyse the detailed flight behaviour during the localisation of a goal surrounded by cylinders that are characterised either by a high contrast in luminance and texture or by mostly motion contrast relative to the background. By relating flight behaviour to the nature of the information available from these landmarks, we aim to identify behavioural strategies that facilitate the processing of visual information during goal localisation. We decompose flight behaviour into prototypical movements using clustering algorithms in order to reduce the behavioural complexity. The determined prototypical movements reflect the honeybee’s saccadic flight pattern that largely separates rotational from translational movements. During phases of translational movements between fast saccadic rotations, the bees can gain information about the three dimensional layout of their environment from the translational optic flow. The prototypical movements reveal the prominent role of sideways and up- or downward movements, which can help bees to gather information about objects, particularly in the frontal visual field. We find that the occurrence of specific prototypes depends on the bees’ distance from the landmarks and the feeder and that changing the texture of the landmarks evokes different prototypical movements. The adaptive use of different behavioural prototypes shapes the visual input and can facilitate information processing in the bees’ visual system during local navigation.

  20. Geodatabase and characteristics of springs within and surrounding the Trinity aquifer outcrops in northern Bexar County, Texas, 2010--11

    Science.gov (United States)

    Clark, Allan K.; Pedraza, Diana E.; Morris, Robert R.; Garcia, Travis J.

    2013-01-01

    The U.S. Geological Survey, in cooperation with the Trinity Glen Rose Groundwater Conservation District, the Edwards Aquifer Authority, and the San Antonio River Authority, developed a geodatabase of springs within and surrounding the Trinity aquifer outcrops in a 331-square-mile study area in northern Bexar County, Texas. The data used to develop the geodatabase were compiled from existing reports and databases, along with spring data collected between October 2010 and September 2011. Characteristics including the location, discharge, and water-quality properties were collected for known springs and documented in the geodatabase. A total of 141 springs were located within the study area, and 46 springs were field verified. The discharge at springs with flow ranged from 0.003 to 1.46 cubic feet per second. The specific conductance of the water discharging from the springs ranged from 167 to 1,130 microsiemens per centimeter at 25 degrees Celsius with a majority of values in the range of 500 microsiemens per centimeter at 25 degrees Celsius.

  1. Slow relaxation dynamics of a mononuclear Er(iii) complex surrounded by a ligand environment with anisotropic charge density.

    Science.gov (United States)

    Lim, Kwang Soo; Kang, Dong Won; Song, Jeong Hwa; Lee, Han Geul; Yang, Mino; Hong, Chang Seop

    2017-01-17

    Two sets of isostructural mononuclear compounds, [Ln(LOMe)2(H2O)2](PF6) [1, Ln = Er; 3, Ln = Gd; LOMe = CpCo{P(O)(O(CH3))2}3] and Ln(LOMe)2(NO3) (2, Ln = Er and 4, Ln = Gd), are synthesized by self-assembly of the respective lanthanide ions and tripodal chelate ligands. The Ln ions are encircled by two LOMe ligands, and two water molecules or one nitrate anion. Each octacoordinated Ln center adopts a distorted square antiprism geometry. The Er complex (2) chelated by a nitrate anion shows slow dynamics in magnetic relaxation, diagnostic of a single-ion magnet. Quantum tunneling in 2 is effectively blocked by application of an external field. Weak intermolecular magnetic interactions occur in 2, and are supported by the magnetic behavior of 4. Chemical dilution of Er with the diamagnetic Y ion can nullify magnetic interactions and suppress quantum tunneling. Generation of slow relaxation dynamics in the Er system is related to the anisotropic charge distribution supplied by the coordination of ligands with different charge densities, as observed in the Dy analogue. This suggests that magnetic anisotropy arises in a coordination system when an anisotropic lanthanide ion (Dy and Er) is surrounded by a ligand environment with anisotropic charge density, resulting in slow magnetic relaxation.

  2. Influence of Surrounding Soil Conditions and Joint Sealing on Seepage Resistance of a Sheet Pile Wall, Three Dimensional Numerical Analyses

    Science.gov (United States)

    Sawicki, Eugeniusz; Wyjadlowski, Marek

    2017-12-01

    The aim of this article is to present 3D numerical calculations results of the seepage resistance of sheet pile (SP) wall with sealed joints. In the present work the leakage through SP wall was determined for one joint of full length. In the analysed example, the SP wall passed through one kind of soil but some conditions (permeability of joint and of surrounding soil) changed depending on the adopted assumptions. To find the distribution of the total head in the calculation area Laplace equation was used. To determine the velocity field Darcy's law was adopted. In the first step, the discharge flowing through the single joint of SP wall based on 3D numerical simulations was determined. In the next step, the joint resistance was estimated and the discharge was found analytically. The results obtained using these two methods were compared. And the conclusions are as follows: it seems possible to estimate the „joint permeability” coefficient using numerical methods, in some conditions the analytical results are far away from numerical ones, due to the nonlinear pressure distribution along the joint, it is necessary to collect in-situ data to confirm the usefulness and reliability of obtained solutions and to proposed more complete methods of determination of SP wall seepage resistance.

  3. Urban land use in Natura 2000 surrounding areas in Vilnius Region, Lithuania.

    Science.gov (United States)

    Pereira, Paulo; Misiūnė, Ieva; Depellegrin, Daniel

    2015-04-01

    Urban development is one of the major causes of land degradation and pressure on protected areas. (Hansen and DeFries, 2007; Salvati and Sabbi, 2011). The urban areas in the fringe of the protected areas are a source of pollutants considered a negative disturbance to the ecosystems services and biodiversity within the protected areas. The distance between urban and protected areas is decreasing and in the future it is estimated that 88% of the world protected areas will be affected by urban growth (McDonald et al., 2008). The surrounding or buffer areas, are lands adjacent to the Natura 2000 territories, which aim to reduce the human influence within the protected areas. Presently there is no common definition of buffer area it is not clear among stakeholders (Van Dasselaar, 2013). The objective of this work is to identify the urban land use in the Natura 2000 areas in Vilnius region, Lithuania. Data from Natura 2000 areas and urban land use (Corine Land Cover 2006) in Vilnius region were collected in the European Environmental Agency website (http://www.eea.europa.eu/). In the surroundings of each Natura 2000 site, we identified the urban land use at the distances of 500, 1000 and 1500 m. The Natura 2000 sites and the urban areas occupied a total of 13.2% and 3.4% of Vilnius region, respectively. However, the urban areas are very dispersed in the territory, especially in the surroundings of Vilnius, which since the end of the XX century is growing (Pereira et al., 2014). This can represent a major threat to Natura 2000 areas ecosystem services quality and biodiversity. Overall, urban areas occupied approximately 50 km2, in the buffer area of 500 m, 95 km2 in buffer area of 1000 m and 131 km2 in the buffer area of 1500 km2. This shows that Natura 2000 surrounding areas in Vilnius region are subjected to a high urban pressure. This is especially evident in the Vilnius city and is a consequence of the uncontrolled urban development. The lack of a clear legislation

  4. Near-field thermal radiation between homogeneous dual uniaxial electromagnetic metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jui-Yung; Basu, Soumyadipta; Yang, Yue; Wang, Liping, E-mail: liping.wang@asu.edu [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States)

    2016-06-07

    Recently, near-field thermal radiation has attracted much attention in several fields since it can exceed the Planck blackbody limit through the coupling of evanescent waves. In this work, near-field radiative heat transfer between two semi-infinite dual uniaxial electromagnetic metamaterials with two different material property sets is theoretically analyzed. The near-field radiative heat transfer is calculated using fluctuational electrodynamics incorporated with anisotropic wave optics. The underlying mechanisms, namely, magnetic hyperbolic mode, magnetic surface polariton, electrical hyperbolic mode, and electrical surface polariton, between two homogeneous dual uniaxial electromagnetic metamaterials are investigated by examining the transmission coefficient and the spectral heat flux. The effect of vacuum gap distance is also studied, which shows that the enhancement at smaller vacuum gap is mainly due to hyperbolic mode and surface plasmon polariton modes. In addition, the results show that the contribution of s-polarized waves is significant and should not be excluded due to the strong magnetic response regardless of vacuum gap distances. The fundamental understanding and insights obtained here will facilitate the finding and application of novel materials for near-field thermal radiation.

  5. Proposing local trees diversity for rehabilitation of degraded lowland areas surrounding springs

    Directory of Open Access Journals (Sweden)

    SOEJONO

    2013-04-01

    Full Text Available Soejono, Budiharta S, Arisoesilaningsih E. 2013. Proposing local trees diversity for rehabilitation of degraded lowland areas surrounding water spring. Biodiversitas 14: 37-42. This study was aimed to propose alternative trees diversity for rehabilitation of degraded lowland area surrounding spring. Data were collected by vegetation analysis of three sampling sites (1st. Cowek, 2nd Gajahrejo, 3rd Parerejo to determine density, frequency, dominancy, diversity index and Important Value Index (IVI. The lists of plants in three sites were then compiled into an integrated list and used as reference for developing questionnaire. The questionnaire was then distributed to respondents who were chosen randomly. We recorded their preferences of tree species in rehabilitation program based on socio-economical and ecological aspects. Selected species were then proposed as alternative plants for rehabilitation of degraded spring area based on landscape topography and remaining vegetation coverage. The results showed that species diversity of Moracecae family was the highest than other families. In term of ecological aspect, Ficus racemosa, Artocarpus elasticus, Bambusa blumeana, Dendrocalamus asper, Gigantochloa atter, Ficus benjamina, Syzygium samarangensis and Ficus virens showed high Important Value Index. On the other hand, based on socio-economic aspects, Ficus benjamina, Artocarpus elasticus, Artocarpus altilis, Artocarpus altilis “Seedless”, Durio zbethinus, Ficus drupacea, Pangium edule, Ficus varigata, Michelia champaca, Aleurites moluccana and Ficus racemosa were the most preferred species by local community. Based on topography and vegetation coverage, spring surrounding areas were were classified into four: steep and open, flat and open, steep and dense, and flat and dense. Therefore among of 120 species found in all sampling sites, there were respectively 63.3%, 95%, 25% and 44.16% species to be proposed and planted for rehabilitation in the

  6. The surrounding landscape influences the diversity of leaf-litter ants in riparian cloud forest remnants.

    Science.gov (United States)

    García-Martínez, Miguel Á; Valenzuela-González, Jorge E; Escobar-Sarria, Federico; López-Barrera, Fabiola; Castaño-Meneses, Gabriela

    2017-01-01

    Riparian vegetation is a distinctive and ecologically important element of landscapes worldwide. However, the relative influence of the surrounding landscape on the conservation of the biodiversity of riparian remnants in human-modified tropical landscapes is poorly understood. We studied the surrounding landscape to evaluate its influence on leaf-litter-ant alpha and beta diversity in riparian remnants in the tropical montane cloud forest region of central Veracruz, Mexico. Sampling was carried out in 12 sites with riparian vegetation during both rainy (2011) and dry (2012) seasons. Ten leaf-litter samples were collected along a 100-m transect per site and processed with Berlese-Tullgren funnels and Winkler sacks. Using remotely-sensed and ground-collected data, we characterized the landscape around each site according to nine land cover types and computed metrics of landscape composition and configuration. We collected a total of 8,684 ant individuals belonging to 53 species, 22 genera, 11 tribes, and 7 subfamilies. Species richness and the diversity of Shannon and Simpson increased significantly in remnants immersed in landscapes with a high percentage of riparian land cover and a low percentage of land covers with areas reforested with Pinus, cattle pastures, and human settlements and infrastructure. The composition of ant assemblages was a function of the percentage of riparian land cover in the landscape. This study found evidence that leaf-litter ants, a highly specialized guild of arthropods, are mainly impacted by landscape composition and the configuration of the focal remnant. Maintaining or improving the surrounding landscape quality of riparian vegetation remnants can stimulate the movement of biodiversity among forest and riparian remnants and foster the provision of ecosystem services by these ecosystems. Effective outcomes may be achieved by considering scientific knowledge during the early stages of riparian policy formulation, in addition to

  7. Conserving Prairie Pothole Region wetlands and surrounding grasslands: evaluating effects on amphibians

    Science.gov (United States)

    Mushet, David M.; Neau, Jordan L.

    2014-01-01

    The maintenance of viable and genetically diverse populations of amphibians in the Prairie Pothole Region of the United States depends on upland as well as wetland over-wintering and landscape level habitat features.Prairie pothole wetlands provide important amphibian breeding habitat while grasslands surrounding these wetlands provide foraging habitat for adults, overwintering habitat for some species, and important connectivity among breeding wetlands.Grasslands surrounding wetlands were found to be especially important for wood frogs and northern leopard frogs, while croplands dominated habitat utilized by Great Plains toads and Woodhouse’s toads.Habitat suitability mapping highlighted (1) the influence of deep-water overwintering wetlands on suitable habitat for four of five anuran species encountered; (2) the lack of overlap between areas of core habitat for both the northern leopard frog and wood frog compared to the core habitat for both toad species; and (3) the importance of conservation programs in providing grassland components of northern leopard frog and wood frog habitat.Currently, there are approximately 7.2 million acres (2.9 million hectares, ha) of habitat in the PPR identified as suitable for amphibians. WRP and CRP wetland and grassland habitats accounted for approximately 1.9 million acres (0.75 million ha) or 26 percent of this total area.Continued loss of amphibian habitat resulting from an ongoing trend of returning PPR conservation lands to crop production, will likely have significant negative effects on the region’s ability to maintain amphibian biodiversity. Conversely, increases in conservation wetlands and surrounding grasslands on the PPR landscape have great potential to positively influence the region’s amphibian populations.

  8. The surrounding landscape influences the diversity of leaf-litter ants in riparian cloud forest remnants

    Science.gov (United States)

    Valenzuela-González, Jorge E.; Escobar-Sarria, Federico; López-Barrera, Fabiola; Castaño-Meneses, Gabriela

    2017-01-01

    Riparian vegetation is a distinctive and ecologically important element of landscapes worldwide. However, the relative influence of the surrounding landscape on the conservation of the biodiversity of riparian remnants in human-modified tropical landscapes is poorly understood. We studied the surrounding landscape to evaluate its influence on leaf-litter-ant alpha and beta diversity in riparian remnants in the tropical montane cloud forest region of central Veracruz, Mexico. Sampling was carried out in 12 sites with riparian vegetation during both rainy (2011) and dry (2012) seasons. Ten leaf-litter samples were collected along a 100-m transect per site and processed with Berlese-Tullgren funnels and Winkler sacks. Using remotely-sensed and ground-collected data, we characterized the landscape around each site according to nine land cover types and computed metrics of landscape composition and configuration. We collected a total of 8,684 ant individuals belonging to 53 species, 22 genera, 11 tribes, and 7 subfamilies. Species richness and the diversity of Shannon and Simpson increased significantly in remnants immersed in landscapes with a high percentage of riparian land cover and a low percentage of land covers with areas reforested with Pinus, cattle pastures, and human settlements and infrastructure. The composition of ant assemblages was a function of the percentage of riparian land cover in the landscape. This study found evidence that leaf-litter ants, a highly specialized guild of arthropods, are mainly impacted by landscape composition and the configuration of the focal remnant. Maintaining or improving the surrounding landscape quality of riparian vegetation remnants can stimulate the movement of biodiversity among forest and riparian remnants and foster the provision of ecosystem services by these ecosystems. Effective outcomes may be achieved by considering scientific knowledge during the early stages of riparian policy formulation, in addition to

  9. Contamination of nebulisers and surrounding air at the bedside of mechanically ventilated patients

    Directory of Open Access Journals (Sweden)

    L Van Heerden

    2017-07-01

    Full Text Available Background. The delivery of aerosolised medication, as performed by nurses and physiotherapists in intensive care units (ICUs, forms an important component of patient care. Objectives. To determine the presence of contamination of nebulisers used within a ventilator circuit; to describe the protocol and clinical practice regarding decontamination and storage of these devices; and to identify micro-organisms colonising contaminated nebulisers and the surrounding air at patients’ bedsides. Methods. A cross-sectional multicentre observational study was conducted, including site and equipment sampling to determine contamination. ICU managers were interviewed to determine the decontamination and storage protocols used for nebulisers in their units. Swabs were taken from nebuliser chambers and streaked onto blood agar plates (BAPs. An air sampler was used to collect air samples from the surrounding bedside environment. The BAPs were incubated for bacterial and fungal contamination. Species of colonies observed in these samples were identified. Results. Sixty-one nebulisers from seven ICUs were sampled (Micro Mist n=37; Aeroneb n=24. Half of the nebulisers (Micro Mist (n=19, 51.4%;Aeroneb (n=12, 50% and most air samples (n=60, 98% presented with contamination. All participating ICUs reported decontamination and storage protocols, but visual inspection of nebulisers suggested that the protocols were not observed. Nebulisers rinsed with alcohol and left open to the environment to dry had the lowest contamination rates. Coagulase-negative Staphylococcus species (spp. were mostly found in the surrounding air and Aeroneb samples, and Enterococcus spp. were mostly found in the Micro Mist nebulisers. Conclusion. Although decontamination and storage protocols for nebulisers were in place, nebuliser and air contamination was high, possibly due to poor staff adherence

  10. 33 CFR 165.1411 - Security zone; waters surrounding U.S. Forces vessel SBX-1, HI.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security zone; waters surrounding U.S. Forces vessel SBX-1, HI. 165.1411 Section 165.1411 Navigation and Navigable Waters COAST GUARD... § 165.1411 Security zone; waters surrounding U.S. Forces vessel SBX-1, HI. (a) Location. The following...

  11. Properties of Schist Extracted in the City of Denizli Surroundings as Construction Material

    OpenAIRE

    Saffet Yağız

    2011-01-01

    There are various type of building stone extracted at stone quarries in the city of Denizli surroundings. Travertine, limestone and schist quarries are the most common in the area. Schist that is one of the units of Menderes massive is the main natural stone sources in Çal, Bekilli and Baklan Triangle in the northeast of the City. The aim of this study is to investigate the usability of schist stone as building stone quarried in the area. To obtain the aim, geological investigations were cond...

  12. Challenges of the Modeling Methods for Investigating the Interaction between the CNT and the Surrounding Polymer

    Directory of Open Access Journals (Sweden)

    Roham Rafiee

    2013-01-01

    Full Text Available The interaction between the carbon nanotubes (CNT and the polymer is a key factor for determining the mechanical, thermal, and electrical properties of the CNT/polymer nanocomposite. However, it is difficult to measure experimentally the interfacial bonding properties between the CNT and the surrounding polymer. Therefore, computational modeling is used to predict the interaction properties. Different scale models, from atomistic to continuum, are critically reviewed addressing the advantages, the disadvantages, and the future challenges. Various methods of improvement for measuring the interaction properties are described. Finally, it is concluded that the semicontinuum modeling may be the best candidate for modeling the interaction between the CNT and the polymer.

  13. THE RECORDS OF HYDRACARINA (ARACHNIDA, ACARINA FROM ESKİŞEHİR AND ITS SURROUNDINGS

    Directory of Open Access Journals (Sweden)

    Sevgi ÜNAL ULUKÜTÜK

    2012-08-01

    Full Text Available This work was done between August 1995 and August 1996 to determine the systematic of Hydracarina fauna in Eskişehir and in its surroundings where also include the Sakarya River. The other aim of this work is to make a contribution to Turkish water-mites fauna.In this study, from 9 families, 4 genuses and 14 species which belong to Hydracarina fauna was determined; identifıcation keys pertaining to the species were organized and explanations supported with pictures and diagrams were illustrated.

  14. Heritability of the morphology of optic nerve head and surrounding structures: The Healthy Twin Study.

    Directory of Open Access Journals (Sweden)

    Jong Chul Han

    Full Text Available Optic nerve head (ONH and surrounding structures such as β-zone peripapillary atrophy (PPA are important structures in glaucomatous pathogenesis. Thus, for understanding genetic components in glaucoma pathogenesis, it is necessary to evaluate the heritability of ONH and surrounding structures. The present study investigated the genetic influences on ONH and surrounding structures such as β-zone PPA and retinal vessels.A total of 1,205 adult twins and their family members (362 monozygotic (MZ twin subjects (181 pairs, 64 dizygotic (DZ twin subjects (32 pairs, and 779 singletons from 261 families, were part of the Korean Healthy Twin Study. ONH parameters including the vertical cup-to-disc ratio, the presence, the area and the location of β-zone PPA and the angular location of retinal vein were measured. The genetic influences on the structures were evaluated using variance-component methods.The intraclass correlation coefficient (ICC values of axial length were highest among the parameters. The ICCs of the area and location of PPA were similar to those of vertical cup-to-disc ratio. However, retinal vessel angular locations showed low ICC values even in MZ twins. After age and sex adjustment, for axial length, vertical cup-to-disc ratio, the presence, area and location of PPA, the estimated narrow-sense heritability was 0.85, 0.48, 0.76, 0.50 and 0.65 in the right eye and 0.84, 0.47, 0.72, 0.46 and 0.72 in the left eye, respectively. The estimated narrow-sense heritability of angular location of the superior and inferior vein was 0.17 and 0.12 in the right eye and 0.13 and 0.05 in the left eye, respectively.ONH and surrounding structures such as vertical cup-to-disc ratio and the presence, the area and the location of β-zone PPA seemed to be determined by the substantial genetic influence, whereas the venous angular location did not.

  15. Parameter studies to determine sensitivity of slug impact loads to properties of core surrounding structures

    Energy Technology Data Exchange (ETDEWEB)

    Gvildys, J.

    1985-01-01

    A sensitivity study of the HCDA slug impact response of fast reactor primary containment to properties of core surrounding structures was performed. Parameters such as the strength of the radial shield material, mass, void, and compressibility properties of the gas plenum material, mass of core material, and mass and compressibility properties of the coolant were used as variables to determine the magnitude of the slug impact loads. The response of the reactor primary containment and the partition of energy were also given. A study was also performed using water as coolant to study the difference in slug impact loads.

  16. Solar Proton Transport within an ICRU Sphere Surrounded by a Complex Shield: Combinatorial Geometry

    Science.gov (United States)

    Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

    2015-01-01

    The 3DHZETRN code, with improved neutron and light ion (Z (is) less than 2) transport procedures, was recently developed and compared to Monte Carlo (MC) simulations using simplified spherical geometries. It was shown that 3DHZETRN agrees with the MC codes to the extent they agree with each other. In the present report, the 3DHZETRN code is extended to enable analysis in general combinatorial geometry. A more complex shielding structure with internal parts surrounding a tissue sphere is considered and compared against MC simulations. It is shown that even in the more complex geometry, 3DHZETRN agrees well with the MC codes and maintains a high degree of computational efficiency.

  17. Overview of the issues surrounding thermal discharges in the Des Plaines River

    Energy Technology Data Exchange (ETDEWEB)

    1979-04-01

    This review effort was undertaken to clarify and, if possible, quantify the issues surrounding the thermal input into the lower Des Plaines River from the Commonwealth Edison Joliet Electrical Generation Facility. The central issue is whether or not a reduction of the thermal discharge from the facility would produce beneficial environmental effects. This issue is clouded due to the fact of a number of environmental problems. These problems include: the river water quality, sediment quality, and barge traffic impacts. These variables, coupled with the uncertain future stream volume and conflicting data, prevent any simplistic conclusions from being drawn. Thus, any short-term study can only result in an overview of the situation.

  18. Centre-surround organization of fast sensorimotor integration in human motor hand area

    DEFF Research Database (Denmark)

    Dubbioso, Raffaele; Raffin, Estelle; Karabanov, Anke

    2017-01-01

    Using the short-latency afferent inhibition (SAI) paradigm, transcranial magnetic stimulation (TMS) of the primary motor hand area (M1HAND) can probe how sensory input from limbs modulates corticomotor output in humans. Here we applied a novel TMS mapping approach to chart the spatial representat...... in M1HAND. Like homotopic SAI, heterotopic SAF was somatotopically expressed in M1HAND. Together, the results provide first-time evidence that fast sensorimotor integration involves centre-inhibition and surround-facilitation in human M1HAND....

  19. Linking student performance in Massachusetts elementary schools with the "greenness" of school surroundings using remote sensing.

    Directory of Open Access Journals (Sweden)

    Chih-Da Wu

    Full Text Available Various studies have reported the physical and mental health benefits from exposure to "green" neighborhoods, such as proximity to neighborhoods with trees and vegetation. However, no studies have explicitly assessed the association between exposure to "green" surroundings and cognitive function in terms of student academic performance. This study investigated the association between the "greenness" of the area surrounding a Massachusetts public elementary school and the academic achievement of the school's student body based on standardized tests with an ecological setting. Researchers used the composite school-based performance scores generated by the Massachusetts Comprehensive Assessment System (MCAS to measure the percentage of 3rd-grade students (the first year of standardized testing for 8-9 years-old children in public school, who scored "Above Proficient" (AP in English and Mathematics tests (Note: Individual student scores are not publically available. The MCAS results are comparable year to year thanks to an equating process. Researchers included test results from 2006 through 2012 in 905 public schools and adjusted for differences between schools in the final analysis according to race, gender, English as a second language (proxy for ethnicity and language facility, parent income, student-teacher ratio, and school attendance. Surrounding greenness of each school was measured using satellite images converted into the Normalized Difference Vegetation Index (NDVI in March, July and October of each year according to a 250-meter, 500-meter, 1,000-meter, and 2000-meter circular buffer around each school. Spatial Generalized Linear Mixed Models (GLMMs estimated the impacts of surrounding greenness on school-based performance. Overall the study results supported a relationship between the "greenness" of the school area and the school-wide academic performance. Interestingly, the results showed a consistently positive significant association

  20. A groundwater-flow model for the Treasure Valley and surrounding area, southwestern Idaho

    Science.gov (United States)

    Bartolino, James R.; Vincent, Sean

    2017-04-17

    The U.S. Geological Survey (USGS), in partnership with the Idaho Department of Water Resources (IDWR) and Idaho Water Resource Board (IWRB), will construct a numerical groundwater-flow model of the Treasure Valley and surrounding area. Resource managers will use the model to simulate potential anthropogenic and climatic effects on groundwater for water-supply planning and management. As part of model construction, the hydrogeologic understanding of the aquifer system will be updated with information collected during the last two decades, as well as new data collected for the study.