These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Read-only high accuracy volume holographic optical correlator  

Microsoft Academic Search

A read-only volume holographic correlator (VHC) is proposed. After the recording of all of the correlation database pages by angular multiplexing, a stand-alone read-only high accuracy VHC will be separated from the VHC recording facilities which include the high-power laser and the angular multiplexing system. The stand-alone VHC has its own low power readout laser and very compact and simple

Tian Zhao; Jingming Li; Liangcai Cao; Qingsheng He; Guofan Jin

2011-01-01

2

Read-only high accuracy volume holographic optical correlator  

NASA Astrophysics Data System (ADS)

A read-only volume holographic correlator (VHC) is proposed. After the recording of all of the correlation database pages by angular multiplexing, a stand-alone read-only high accuracy VHC will be separated from the VHC recording facilities which include the high-power laser and the angular multiplexing system. The stand-alone VHC has its own low power readout laser and very compact and simple structure. Since there are two lasers that are employed for recording and readout, respectively, the optical alignment tolerance of the laser illumination on the SLM is very sensitive. The twodimensional angular tolerance is analyzed based on the theoretical model of the volume holographic correlator. The experimental demonstration of the proposed read-only VHC is introduced and discussed.

Zhao, Tian; Li, Jingming; Cao, Liangcai; He, Qingsheng; Jin, Guofan

2011-10-01

3

Optical Correlator With Complex Holographic Filter  

NASA Technical Reports Server (NTRS)

Experimental real-time optical correlator includes complex-valued holographic filter computed from one of two input scenes. Made more tolerant of errors in patterns to be recognized. Filter function essentially coded hologram computed by Burchhardt's method, in which complex value of each pixel of fast Fourier transform of image represented by three real, nonnegative numbers. In generating optical correlator according to method, phasor of each pixel in Fourier transform represented by intensities in three adjacent pixels.

Chao, Tien-Hsin

1992-01-01

4

Holographic memory with correlator based readout  

Microsoft Academic Search

The investigation of an inverted hybrid digital\\/optical VanderLugt type correlator based on a holographic memory is reported in this paper. A set of reference templates is stored in a photorefractive crystal (PRC) by angular hologram multiplexing. In the filter plane, a phase-modulating liquid crystal television (LCTV) serves as a phase-only input device. During the recognition process, which is based on

M. Duelli; A. R. Pourzand; N. Collings; R. Dandliker

1998-01-01

5

Laser threat discrimination based on volume holographic memory  

Microsoft Academic Search

Volume holographic memory offers a compact means of information storage through angle and wavelength multiplexing in three dimensions. As laser warning systems often use both angle-of-arrival and wavelength information in order to identify and\\/or discriminate among laser threats, volume holographic memory structures are ideally suited for consideration as laser warning receiver sensors. Holographic imaging in volume phase media is examined

Mark L. DeLong; Bradley D. Duncan

1995-01-01

6

Monopole correlations in holographically flavored liquids  

E-print Network

Many-body systems with a conserved U(1) current in (2+1) dimensions may be probed by weakly gauging this current and studying correlation functions of magnetic monopole operators in the resulting dynamical gauge theory. We study such monopole correlations in holographic liquids with fundamental flavor, where the monopole operator is dual to a magnetically charged particle in the bulk. In charge-gapped phases the monopole operator is expected to condense. We show that this condensation is holographically dual to the capping off of the bulk flavor brane and compute the monopole condensate. We argue that from the lower-dimensional point of view this may be understood as a simple example of confinement of a gauge field in the bulk. In a compressible finite-density phase we present a novel calculation of the monopole correlation in space and time: the correlation is power law in time but is Gaussian in space due to interaction with the background charge density.

Nabil Iqbal

2014-09-18

7

Random modulation in high-density holographic data storage and correlation recognition system  

NASA Astrophysics Data System (ADS)

In the holographic data storage system, a shifting diffuser is employed in the reference beam to realize dynamic speckle multiplexing, while another vibrating diffuser is placed in the object beam to realize speckle modulation. These two methods can enlarge the storage capacity with high signal-to-noise rate. Speckle multiplexing can suppress the crosstalk due to multiple longitudinal modes of the small DPL laser. And speckle modulation in volume holographic correlators can suppress the diffraction sidelobes of output correlation signal along both vertical and horizontal direction. Another advantage of the speckle multiplexing and the speckle modulation is that the angular selectivity and the correlation peak are not sensitive to the thickness of the hologram. Finally a demonstration platform of compact holographic storage and correlation recognition system is briefly introduced in this paper.

Jin, Guofan; Cao, Liangcai; He, Qingsheng; Wei, Haoyun; Wu, Minxian

2003-10-01

8

Volume holographic pupils in ray, wave, statistical optics, and Wigner space  

E-print Network

This thesis explores various aspects of the volume holographic pupils to better understand and implement multi-dimensional imaging. A full description and applications of volume holographic pupils are presented in ray, ...

Oh, Se Baek

2009-01-01

9

Doped photopolymers for volume holographic applications  

NASA Astrophysics Data System (ADS)

We fabricate two phenanthrenequinone-doped copolymers which can improve the holographic recording characteristics of phenanthrenequinone-doped poly(methyl-methacrylate) (PQ/PMMA) photopolymer. In these materials, the polymer matrix of PQ/PMMA is modified to be copolymers, which composed of either poly(methyl-methacrylate-co -trimethylolpropane-triacrylate) or poly(methyl-methacrylate-co-acrylic acid 2-phenoxyethyl ester), respectively. With the chemical analyses of these materials before and after light exposure, we investigate the physical mechanism of the holographic recording in those copolymer samples. In addition, the holographic characteristics of different samples, including dynamic range and sensitivity, have been measured. These experimental results demonstrate that modification of the monomers is an efficient method to improve the material properties.

Lin, Shiuan Huei; Lin, June-Hua; Hsiao, Yi-Nan; Hsu, Ken Y.

2006-08-01

10

Holographic associative memory with nonlinearities in the correlation domain.  

PubMed

We describe a shift-invariant all-optical holographic associative memory implemented using phase conjugate mirrors and Fourier transform holograms. A key feature of our system is the large storage capacity obtained through the use of nonlinearities in the correlation domain. The use of angularly multiplexed plane wave reference beams allows access to the correlation domain where nonlinearities in the phase conjugate mirrors can be used to reduce greatly crosstalk and correlation noise. PMID:20454419

Owechko, Y; Dunning, G J; Marom, E; Soffer, B H

1987-05-15

11

Second-harmonic diffraction from holographic volume grating.  

PubMed

The full polarization property of holographic volume-grating enhanced second-harmonic diffraction (SHD) is investigated theoretically. The nonlinear coefficient is derived from a simple atomic model of the material. By using a simple volume-grating model, the SHD fields and Mueller matrices are first derived. The SHD phase-mismatching effect for a thick sample is analytically investigated. This theory is justified by fitting with published experimental SHD data of thin-film samples. The SHD of an existing polymethyl methacrylate (PMMA) holographic 2-mm-thick volume-grating sample is investigated. This sample has two strong coupling linear diffraction peaks and five SHD peaks. The splitting of SHD peaks is due to the phase-mismatching effect. The detector sensitivity and laser power needed to measure these peak signals are quantitatively estimated. PMID:16985536

Nee, Tsu-Wei

2006-10-01

12

Hybrid surface-relief/volume one dimensional holographic gratings  

NASA Astrophysics Data System (ADS)

Many one dimensional optically patterned photopolymers exist as surface relief or volume phase gratings. However, as far as we know, holographically recorded acrylate-based gratings in which both configurations are present are not described in literature. In this work we report a two steps fabrication process in which a large-area high-resolution hybrid volume/surface relief grating phase gratings is created in a thin film of multiacrylate material spinned on a proper designed substrate. Optical and morphological investigations, made on the optically patterned area, confirm the presence of a one dimensional double (surface relief and Bragg volume phase) periodic structure.

Lucchetta, D. E.; Spegni, P.; Di Donato, A.; Simoni, F.; Castagna, R.

2015-04-01

13

Three-dimensional display based on volume holographic kinoform in photopolymer  

NASA Astrophysics Data System (ADS)

Holographic three-dimensional (3D) display is a promising technique since it can present a 3D scene with all characteristics of real-world objects. Volume holography provides big data capacity for high resolution 3D display. It has the advantages of good wavelength and angular multiplexing properties over planar holography because of the Bragg condition. 3D display can be realized by recording holographic kinoforms into a volume holographic polymer. The purephase wavefront of a 3D object is generated and uploaded by a phase-only spatial light modulator. The phase-modulated data page is recorded in the volume holographic photopolymer. The 3D object can be reconstructed at a designed distance behind the volume holographic polymer by illuminating with the reference beam. Volume holographic kinoform can realize high-resolution 3D display without any lens or glasses by improving the space-bandwidth product of the display system.

Wang, Zheng; Cao, Liangcai; Liu, Fanglin; Li, Chengmingyue; Zhang, Hao; Jin, Guofan

2014-09-01

14

Aspects of current correlators in holographic theories with hyperscaling violation  

NASA Astrophysics Data System (ADS)

We study the low-energy and low-momentum behavior of current correlators in a class of holographic zero-temperature, finite-density critical theories which do not respect the hyperscaling relation. The dual holographic description is assumed to be given by probe D-branes embedded in background geometries characterized by a dynamical critical exponent z and a hyperscaling violation exponent ?. We show that a subset of these theories with 1?z<2(1-?/d) exhibit a stable, linearly dispersing mode in their low-energy spectrum of excitations. This mode, which appears as a pole in the retarded correlators of charge density and longitudinal currents, has some characteristics similar to that of the zero sound in Fermi liquids. Given some reasonable assumptions, we argue that the class of theories with ?=d-1 that logarithmically violate the area law in the entanglement entropy in a manner reminiscent of theories with Fermi surfaces does not exhibit a zero-sound-like mode in the low-energy spectrum of the probe sector. Furthermore, utilizing the holographic Wilsonian approach, we explicitly show that such a mode has a natural interpretation as a Goldstone boson arising from the spontaneous breaking of a specific symmetry.

Edalati, Mohammad; Pedraza, Juan F.

2013-10-01

15

Dynamic speckle multiplexing scheme in volume holographic data storage and its realization  

NASA Astrophysics Data System (ADS)

Dynamic speckle multiplexing scheme in volume holographic data storage is proposed, since it offers a novel multiplexing geometry, and could be combined with other schemes to make the full use of the dynamic ranges. In this scheme, a random diffuser is added in the original reference path of the classical 90º setup. In this paper, we analyzed the propagation of the speckle field in the holographic system and established the related theoretical model based on the dynamic speckle auto-correlation function and diffraction theory. We successfully realized the dynamic speckle multiplexing in our experimental system and reached a storage density of 4.6 Gigapixels/cm3 based on the DPL laser source.

He, Qingsheng; Wang, Jinnan; Wang, Jiangang; Woo, Minxian; Jin, Guofan

2003-02-01

16

Multiquark Correlations in Light Mesons and Baryons from holographic QCD  

SciTech Connect

A hadron's multiquark content reflects itself in the quark composition of the interpolator with which it has maximal overlap. The AdS/CFT dictionary translates the anomalous dimension of this interpolator into a mass correction for the corresponding dual mode. Hence such bulk-mass corrections can carry specific information on multiquark correlations. Two prominent examples are studied by implementing this robust and universal holographic mechanism into AdS/QCD gravity duals. In the baryon sector bulk-mass corrections are used to describe systematic good (i.e. maximally attractive) diquark effects. The baryon sizes are predicted to decrease with increasing good-diquark content, and the masses of all 48 observed light-quark baryon states are reproduced with unprecedented accuracy. Our approach further provides the first holographic description of a dominant tetraquark component in the lowest-lying scalar mesons. The tetraquark ground state emerges naturally as the lightest scalar nonet whereas higher excitations become heavier than their quark--antiquark counterparts and are thus likely to dissolve into the multiparticle continuum.

Forkel, Hilmar [Institut fuer Physik, Humboldt-Universitaet zu Berlin, D-12489 Berlin (Germany)

2011-10-21

17

Application of phase-conjugate mirrors during recording of volume holographic memories.  

PubMed

We propose, demonstrate, and analyze the application of phase-conjugate mirrors during the recording of volume holographic memories. Our results show that using phase-conjugate mirrors during recording improves the uniformity of the holographic gratings and increases the recording speed. Theoretical simulations agree with experimental results. PMID:18305685

Yang, M; Gu, C

1999-02-10

18

Application of Phase-Conjugate Mirrors During Recording of Volume Holographic Memories  

NASA Astrophysics Data System (ADS)

We propose, demonstrate, and analyze the application of phase-conjugate mirrors during the recording of volume holographic memories. Our results show that using phase-conjugate mirrors during recording improves the uniformity of the holographic gratings and increases the recording speed. Theoretical simulations agree with experimental results.

Yang, Miao; Gu, Claire

1999-02-01

19

Laser-induced fluorescence imaging of subsurface tissue structures with a volume holographic  

E-print Network

Laser-induced fluorescence imaging of subsurface tissue structures with a volume holographic, 2008 A three-dimensional imaging system incorporating multiplexed holographic gratings to visualize such as a phenanthrenquinone poly(methyl methacrylate) photopolymer have narrowband angular and spectral transmittance

Barton, Jennifer K.

20

The Impact of Volume Phase Holographic Filters and Gratings on the Development of Raman Instrumentation  

ERIC Educational Resources Information Center

Volume phase holographic (VPH) optical elements have made a major contribution to Raman spectroscopy by providing notch filters, and VPH gratings that provide remarkable performance advantages over previous technologies. Holographic notch filters have eliminated Rayleigh scattered laser light from single monochromators, thereby contributing to the…

Owen, Harry

2007-01-01

21

Volume phase holographic gratings for astronomy based on solid photopolymers  

NASA Astrophysics Data System (ADS)

Volume Phase Holographic Gratings (VPHG) are gaining more and more interest as optical dispersing elements in new astronomical spectrographs at low and medium resolution. A key point is the development of new photosensitive materials suitable to produce VPHGs that match the stringent requirements of the astronomical environment. Here we report on the performances of VPHG based on Bayfol®HX solid photopolymer films developed by Bayer MaterialScience AG. Parameters affecting the grating efficiency (e. g. photopolymer film thickness and refractive index modulation) are measured and linked to the performances of VPHG working in the VIS-NIR region. Moreover, the behavior at low temperature and the aging properties of such materials/gratings are reported. Substantial efficiency gains on a new VPHG installed at the Asiago's spectrograph are shown and proven on the observation of a standard star (hr5501).

Zanutta, Alessio; Bianco, Andrea; Insausti, Maider; Garzón, Francisco

2014-07-01

22

Cryogenic Volume-Phase Holographic Grisms for MOIRCS  

NASA Astrophysics Data System (ADS)

We have developed high-dispersion VPH (volume phase holographic) grisms with zinc selenide (ZnSe) prisms for the cryogenic optical system of MOIRCS (Multi-Object near-InfraRed Camera and Spectrograph) for Y-, J-, H-, and K-band observations. We fabricated VPH gratings using a hologram resin. After several heat cycles at between room temperature and 120 K, the VPH gratings were assembled to grisms by gluing with two ZnSe prisms. Several heat cycles were also carried out for the grisms before being installed into MOIRCS. We measured the efficiencies of the VPH grisms in a laboratory, and found them to be 70%-82%. The performances obtained by observations of MOIRCS with the 8.2 m Subaru Telescope have been found to be very consistent with the results in the laboratory test. This is the first astronomical application of cryogenic VPH grisms.

Ebizuka, Noboru; Ichiyama, Kotaro; Yamada, Toru; Tokoku, Chihiro; Onodera, Masato; Hanesaka, Mai; Kodate, Kashiko; Katsuno Uchimoto, Yuka; Maruyama, Miyoko; Shimasaku, Kazuhiro; Tanaka, Ichi; Yoshikawa, Tomohiro; Kashikawa, Nobunari; Iye, Masanori; Ichikawa, Takashi

2011-03-01

23

Angle amplifier based on multiplexed volume holographic gratings  

NASA Astrophysics Data System (ADS)

Angle amplifier of laser beam scanner is a widely used device in optical systems. Volume holographic optical elements can be applied in the angle amplifier. Compared with the traditional angle amplifier, it has the advantages of high angle resolution, high diffraction efficiency, small size, and high angle magnification and flexible design. Bragg anglewavelength- compensating recording method is introduced. Because of the Bragg compensatory relation between angle and wavelength, this device could be recorded at another wavelength. The design of the angle amplifier recording at the wavelength of 514.2nm for the working wavelength of 632.8nm is described. An optical setup for recording the angle amplifier device is designed and discussed. Experimental results in the photorefractive crystal Fe:LiNbO 3 demonstrate the feasibility of the angle amplifier scheme.

Cao, Liangcai; Zhao, Yifei; He, Qingsheng; Jin, Guofan

2008-03-01

24

Real-time three-dimensional microscopy with volume holographic pupils  

E-print Network

Multiplex volume holographic pupils have been demonstrated in the capacity of imagers with optical slicing and real-time (scanning-free) three-dimensional imaging capability. We overview application to microscopy and ...

Kostuk, Raymond K.

25

Phase aberration correction by correlation in digital holographic adaptive optics  

PubMed Central

We present a phase aberration correction method based on the correlation between the complex full-field and guide-star holograms in the context of digital holographic adaptive optics (DHAO). Removal of a global quadratic phase term before the correlation operation plays an important role in the correction. Correlation operation can remove the phase aberration at the entrance pupil plane and automatically refocus the corrected optical field. Except for the assumption that most aberrations lie at or close to the entrance pupil, the presented method does not impose any other constraints on the optical systems. Thus, it greatly enhances the flexibility of the optical design for DHAO systems in vision science and microscopy. Theoretical studies show that the previously proposed Fourier transform DHAO (FTDHAO) is just a special case of this general correction method, where the global quadratic phase term and a defocus term disappear. Hence, this correction method realizes the generalization of FTDHAO into arbitrary DHAO systems. The effectiveness and robustness of this method are demonstrated by simulations and experiments. PMID:23669707

Liu, Changgeng; Yu, Xiao; Kim, Myung K.

2013-01-01

26

Volume holographic reflection endoscope for in-vivo ovarian cancer clinical studies  

NASA Astrophysics Data System (ADS)

We present the design for an endoscopic system capable of imaging tissues of the ovary at two selected imaging depths simultaneously. The method utilizes a multiplexed volume hologram to select wavefronts from different depths within the tissue. It is the first demonstration of an endoscopic volume holographic imaging system. The endoscope uses both gradient index (GRIN) optical components and off the shelf singlet lenses to relay an image from the distal tip to the proximal end. The endoscope has a minimum diameter of 3.75 mm. The system length is 30 cm which is connected to a handle that includes the holographic components and optics that relay the image to a camera. Preliminary evaluation of the endoscope was performed with tissue phantoms and calibrated targets, which shows lateral resolution ? 4 ?m at an operating wavelength of 660 nm. The hologram is recorded in phenanthraquinone doped poly methacrylate and is designed to produce images from two tissue depths. One image is obtained at the tissue surface and the second 70 ?m below the surface. This method requires no mechanical scanning and acquires an image at the camera frame rate. The preliminary ex-vivo results show good correlation with histology sections of the same tissue sections.

Howlett, I. D.; Gordon, M.; Brownlee, J. W.; Barton, J. K.; Kostuk, R. K.

2014-03-01

27

Volume Holographic Reflection Endoscope for In-Vivo Ovarian Cancer Clinical Studies  

PubMed Central

We present the design for an endoscopic system capable of imaging tissues of the ovary at two selected imaging depths simultaneously. The method utilizes a multiplexed volume hologram to select wavefronts from different depths within the tissue. It is the first demonstration of an endoscopic volume holographic imaging system. The endoscope uses both gradient index (GRIN) optical components and off the shelf singlet lenses to relay an image from the distal tip to the proximal end. The endoscope has a minimum diameter of 3.75 mm. The system length is 30 cm which is connected to a handle that includes the holographic components and optics that relay the image to a camera. Preliminary evaluation of the endoscope was performed with tissue phantoms and calibrated targets, which shows lateral resolution ? 4 ?m at an operating wavelength of 660 nm. The hologram is recorded in phenanthraquinone doped poly methacrylate and is designed to produce images from two tissue depths. One image is obtained at the tissue surface and the second 70 ?m below the surface. This method requires no mechanical scanning and acquires an image at the camera frame rate. The preliminary ex-vivo results show good correlation with histology sections of the same tissue sections. PMID:25009709

Howlett, I. D.; Gordon, M.; Brownlee, J. W.; Barton, J. K.; Kostuk, R. K.

2014-01-01

28

A 6-beam combiner using superimposed volume index holographic gratings  

E-print Network

In this thesis, a 6-beam combiner using multiplexed holograms in dye-doped polymer is investigated. It is realized by recording six superimposed holographic gratings, which show uniform diffraction efficiency. The coupled wave theory for N...

Yum, HoNam

2005-11-01

29

Passive quasi-monochromatic depth discrimination using a coherence imager with volume holographic pupil  

Microsoft Academic Search

We present a new passive depth detection method for quasi-monochromatic and spatially incoherent objects. We utilize the wavefront discrimination properties of a volume holographic pupil combined with a measurement of the degree of coherence of the diffracted field. Depth detection is posed as the Bayesian hypothesis testing on the outcome of the coherence measurement. We present the analysis of our

Se Baek Oh; George Barbastathis

2008-01-01

30

Photochromic polymers for making volume phase holographic gratings: between theory and practice  

NASA Astrophysics Data System (ADS)

Volume Phase Holographic Gratings (VPHGs) are dispersing elements which are finding wide spread in modern optical instrumentations, also in the astronomical field. Since photochromic materials show a change in the refractive index (?n) upon photoirradiation, in principle they can be conveniently applied to produce rewritable holographic devices for the near-IR region. Diarylethene-based photochromic films with ?n large enough to meet the basic requirements have been obtained. Photochromic VPHGs have been written by using a custom made holographic set-up, based on a Lloyd's mirror configuration. The efficiency of the photochromic gratings has been measured at different wavelength in the NIR region. A theoretical model to predict the refractive index profile as function of the substrate features has been developed. Finally, the efficiencies calculated by using the RCWA approach have been compared with the experimental values.

Bianco, Andrea; Pariani, Giorgio; Bertarelli, Chiara; Zerbi, Filippo M.

2010-07-01

31

Characterization of volume holographic recording in photopolymerizable nanoparticle-(thiol-ene) polymer composites at 404 nm  

NASA Astrophysics Data System (ADS)

We report on the photopolymerization dynamics and the volume holographic recording properties of a thiol-ene based nanoparticle-polymer composite (NPC) doped with a blue-sensitive photoinitiator, Darocur® TPO, by using a highly coherent blue diode laser operating at a wavelength of 404 nm. Our study indicates that volume gratings recorded in the NPC amount to meeting the material requirements of refractive index modulation and material recording sensitivity for holographic data storage media. It is also found that polymerization shrinkage of recorded NPC gratings is higher than that of the same thiol-ene based NPC with a green (523 nm)-sensitive photoinitiator, Irgacure® 784/BzO2. We attribute such a difference in shrinkage to the photopolymerization dynamics at these recording wavelengths. We show that this shrinkage increase at 404 nm can be mitigated to some extent by controlling the thiol-ene stoichiometry in the NPC.

Kawana, Masaru; Takahashi, Jun-ichiro; Yasui, Satoru; Tomita, Yasuo

2015-02-01

32

Position feedback system for volume holographic storage media  

DOEpatents

A method of holographic recording in a photorefractive medium wherein stored holograms may be retrieved with maximum signal-to noise ratio (SNR) is disclosed. A plurality of servo blocks containing position feedback information is recorded in the crystal and made non-erasable by heating the crystal. The servo blocks are recorded at specific increments, either angular or frequency, depending whether wavelength or angular multiplexing is applied, and each servo block is defined by one of five patterns. Data pages are then recorded at positions or wavelengths enabling each data page to be subsequently reconstructed with servo patterns which provide position feedback information. The method of recording data pages and servo blocks is consistent with conventional practices. In addition, the recording system also includes components (e.g. voice coil motor) which respond to position feedback information and adjust the angular position of the reference angle of a reference beam to maximize SNR by reducing crosstalk, thereby improving storage capacity.

Hays, Nathan J. (San Francisco, CA); Henson, James A. (Morgan Hill, CA); Carpenter, Christopher M. (Sunnyvale, CA); Akin, Jr.. William R. (Morgan Hill, CA); Ehrlich, Richard M. (Saratoga, CA); Beazley, Lance D. (San Jose, CA)

1998-07-07

33

Generation of tunable-volume transmission-holographic gratings at low light levels  

SciTech Connect

By utilizing giant Kerr nonlinearity obtained by electromagnetically induced transparency (EIT), tunable volume transmission holographic gratings for a weak probe field can be generated by means of a standing-wave signal field at low light levels in a four-level N-type ultracold atomic ensemble. The induced grating can be characterized as a mixed volume holographic grating with a strong phase modulation accompanied by a weak amplitude modulation. Based on Kogelnik's coupled-wave theory in optical holography, we find that high diffraction efficiency (up to 85%) and sensitive angular selectivity (up to {+-}0.000149 rad) can be achieved for the induced grating in the Bragg diffraction regime. And, both of them can be dynamically controlled by tuning the weak standing-wave signal field and the coupling field. Our study not only develops a fundamental understanding of volume diffraction effects in EIT media, but also provides a practical prototype of EIT-based holographic devices for all-optical classical and quantum information processing.

Zhao, L.; Duan, Wenhui [Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Yelin, S. F. [Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States); ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States)

2011-09-15

34

Four-point correlator of vector currents and electric current susceptibility in holographic QCD  

E-print Network

In this work we calculate the four-point correlation function of vector quark currents of QCD via holographic QCD model. Computing the correlator we take into account the exchange of vector and axial vector bosons and dilaton in the bulk. The result is used for calculation of the two-point correlator of electromagnetic currents in external magnetic field at zero momentum, related to RHIC experiments, chiral magnetic effect and lattice study. At zero temperature we find this quantity to be loosely connected with chiral symmetry breaking and strongly dependent on the confinement properties. Some features of the AdS/QCD models are also discussed.

Alexander Krikun

2010-03-15

35

Laser-induced fluorescence imaging of subsurface tissue structures with a volume holographic spatial-spectral imaging system.  

PubMed

A three-dimensional imaging system incorporating multiplexed holographic gratings to visualize fluorescence tissue structures is presented. Holographic gratings formed in volume recording materials such as a phenanthrenquinone poly(methyl methacrylate) photopolymer have narrowband angular and spectral transmittance filtering properties that enable obtaining spatial-spectral information within an object. We demonstrate this imaging system's ability to obtain multiple depth-resolved fluorescence images simultaneously. PMID:18794943

Luo, Yuan; Gelsinger-Austin, Paul J; Watson, Jonathan M; Barbastathis, George; Barton, Jennifer K; Kostuk, Raymond K

2008-09-15

36

Holographic volume displacement calculations via multiwavelength digital holography.  

PubMed

In this work multiwavelength digital holography is applied to calculate the volume displacement of various topographic surface features. To accurately measure the volume displacement of macroscopic features, long synthetic wavelengths up to several millimeters are generated using tunable IR laser sources. Practical methods of implementation are considered, including geometric effects of both Michelson and Mach-Zehnder recording configurations and error due to wavelength selection. PMID:24663416

Williams, L; Banerjee, P P; Nehmetallah, G; Praharaj, S

2014-03-10

37

Multiple stereoscopic pairs recording system based on volume holographic memory  

Microsoft Academic Search

The angular multiplexing method was used for multiple stereoscopic pair holograms within a common volume. When the reference beam with Bragg condition is illuminated for reconstruction, stereoscopic images are suitably projected on the left and right display plane for stereoscopic viewing

Seung-Hyun Lee; Sang-Yi Yi; Eun-Soo Kim

1999-01-01

38

Analysis of volume holographic storage allowing large-angle illumination  

NASA Astrophysics Data System (ADS)

Advanced technological developments have stimulated renewed interest in volume holography for applications such as information storage and wavelength multiplexing for communications and laser beam shaping. In these and many other applications, the information-carrying wave fronts usually possess narrow spatial-frequency bands, although they may propagate at large angles with respect to each other or a preferred optical axis. Conventional analytic methods are not capable of properly analyzing the optical architectures involved. For mitigation of the analytic difficulties, a novel approximation is introduced to treat narrow spatial-frequency band wave fronts propagating at large angles. This approximation is incorporated into the analysis of volume holography based on a plane-wave decomposition and Fourier analysis. As a result of the analysis, the recently introduced generalized Bragg selectivity is rederived for this more general case and is shown to provide enhanced performance for the above indicated applications. The power of the new theoretical description is demonstrated with the help of specific examples and computer simulations. The simulations reveal some interesting effects, such as coherent motion blur, that were predicted in an earlier publication.

Shamir, Joseph

2005-05-01

39

Generation of individually modulated femtosecond pulse string by multilayer volume holographic gratings.  

PubMed

A scheme to generate individually modulated femtosecond pulse string by multilayer volume holographic grating (MVHG) is proposed. Based on Kogelnik's coupled-wave theory and matrix optics, temporal and spectral expressions of diffracted field are given when a femtosecond pulse is diffracted by a MVHG. It is shown that the number of diffracted sub-pulses in the pulse string equals to the number of grating layers of the MVHG, peak intensity and duration of each diffracted sub-pulse depend on thickness of the corresponding grating layer, whereas pulse interval between adjacent sub-pulses is related to thickness of the corresponding buffer layer. Thus by modulating parameters of the MVHG, individually modulated femtosecond pulse string can be acquired. Based on Bragg selectivity of the volume grating and phase shift provided by the buffer layers, we give an explanation on these phenomena. The result is useful to design MVHG-based devices employed in optical communications, pulse shaping and processing. PMID:25401645

Yan, Xiaona; Gao, Lirun; Yang, Xihua; Dai, Ye; Chen, Yuanyuan; Ma, Guohong

2014-10-20

40

Three Dynamical Photorefractive Systems: a Novelty Filter, Volume Holographic Interconnection, and a Ring Resonator with Photorefractive Gain and Loss  

Microsoft Academic Search

This thesis addresses three dynamic photorefractive systems: a novelty filter, volume holographic interconnection, and a ring resonator with both photorefractive gain and loss. Our interest in dynamical systems is motivated by a desire to understand how to build optical processors for computations difficult for conventional computers. We choose optics as the medium because of the ease of parallelism, and photorefractive

Diana Marie Lininger

1990-01-01

41

Simulation and analysis of volume holographic gratings integrated in collimation optics for wavelength stabilization  

NASA Astrophysics Data System (ADS)

Integrating volume holographic gratings into micro-optical components such as cylindrical fast-axis collimation lenses (VHG-FAC) for diode lasers constitutes a promising concept for wavelength stabilization by forming an external cavity laser. Compared to standard wavelength stabilization configurations the integrated element reduces the alignment complexity and is furthermore insensitive to the smile-error of diode laser bars. In order to configure and optimize these components the diffraction of the divergent field distribution of a broad area semiconductor laser must be calculated. The present paper presents the extension of the coupled-mode theory in order to calculate the spectral distribution of the diffracted field and the coupling efficiency within the external cavity. The model was extended to three-dimensional space and supplemented to include surface effects, polarization dependency and wave-optical propagation. The asymmetric spectral distribution emitted by an external cavity laser with VBG-FAC is tracked back to the feedback of highly divergent radiation diffracted at the holographic grating. Power losses due to the coupling efficiency within the cavity are also calculated for various field distributions and compared with experimental data. In summary the mathematical model allows to estimate the minimum spectral width and the losses using a VHG-FAC in an external cavity. Thus the injection locking concept using the VHG-FAC can be compared to the spectral characteristics and estimated power losses of standard wavelength stabilization configurations, e.g. the alignment of the grating in the collimated beam.

Hengesbach, S.; Witte, U.; Traub, M.; Hoffmann, D.

2011-03-01

42

Volume phase holographic grating used for beams combination of RGB primary colors  

NASA Astrophysics Data System (ADS)

Volume phase holographic grating (VPHG) has the characteristics of high diffraction efficiency, high signal to noise ratio, high wavelength and angular selectivity, low scattering , low absorption and low cost. It has been widely used in high resolution spectrometer, wavelength division multiplexing and pulse compression technique. In this paper, a novel kind of RGB primary colors beams combiner which is consisted of a transmission VPHG and a reflection VPHG as core components is proposed. The design idea of the element is described in detail. Based on the principle of VPHG, the rigorous coupled wave analysis (RCWA) and Kogelnik's coupled wave theory, diffraction properties of the transmission and reflection VPHG are studied theoretically. As an example, three primary colors at wavelengths of 632.8nm, 532nm and 476.5nm are taken into account. Dichromated gelatin (DCG) is used as the holographic recording material. The grating parameters are determined by the Bragg conditions. The TE and TM wave diffraction efficiency, the wavelength selectivity and the angular selectivity of the transmission and reflection VPHG are calculated and optimized by setting the amplitude of the index modulation (?n) and the thickness of the gelatin layer (d) by applying Kogelnik's coupled wave theory and G-solver software, respectively. The theoretical calculating results give guidance for further manufacture of the element.

Liu, Hui; Zhang, Xizhao; Tang, Minxue

2013-12-01

43

Speckle-reduced three-dimensional volume holographic display by use of integral imaging.  

PubMed

We propose a method to implement a speckle-reduced coherent three-dimensional (3D) display system by a combination of integral imaging and photorefractive volume holographic storage. The 3D real object is imaged through the microlens array and stored in the photorefractive crystal. During the reconstruction process a phase conjugate reading beam is used to minimize aberration, and a rotating diffuser located on the imaging plane of the lens array is employed to reduce the speckle noise. The speckle-reduced 3D image with a wide viewing angle can be reconstructed by use of the proposed system. Experimental results are presented and optical parameters of the proposed system are discussed in detail. PMID:12022663

Shin, Seung-Ho; Javidi, Bahram

2002-05-10

44

Viewing-angle enhancement of speckle-reduced volume holographic three-dimensional display by use of integral imaging.  

PubMed

In a conventional integral imaging system the viewing angle is limited by the f-number of the microlens. To overcome this limitation we employ a phase-conjugate beam to read out elemental images, which are stored in photorefractive volume holographic storage, while the rotating diffuser reduces the speckle noise. In the proposed system the viewing angle can be enhanced over the f-number limitation. Experimental results and discussions of viewing parameters are presented. PMID:12224779

Shin, Seung-Ho; Javidi, Bahram

2002-09-10

45

Viewing-angle enhancement of speckle-reduced volume holographic three-dimensional display by use of integral imaging  

NASA Astrophysics Data System (ADS)

In a conventional integral imaging system the viewing angle is limited by the f-number of the microlens. To overcome this limitation we employ a phase-conjugate beam to read out elemental images, which are stored in photorefractive volume holographic storage, while the rotating diffuser reduces the speckle noise. In the proposed system the viewing angle can be enhanced over the f-number limitation. Experimental results and discussions of viewing parameters are presented.

Shin, Seung-Ho; Javidi, Bahram

2002-09-01

46

Insensitivity of Speckle Multiplexing to Multi-longitudinal Modes of Laser in Volume Holographic Storage  

Microsoft Academic Search

If a diode pumped solid state laser is used in a holographic storage system, its multi longitudinal modes may damage the angular selectivity of the hologram and introduce more cross talk in the system. By theoretical analysis, we found that with adopting the speckle multiplexing scheme, holographic systems are no longer sensitive to the multi longitudinal modes of the laser

Jin-Nan Wang; Shu-Rong He; Qing-Sheng He; Dong Huang; Guo-Fan Jin

2003-01-01

47

Wavelength stabilization of high power laser systems using volume holographic gratings  

NASA Astrophysics Data System (ADS)

We present our latest experimental results in wavelength stabilization of high power laser diode systems by using Volume Holographic (Bragg) Gratings. Such systems are used as optical pumps to increase the efficiency and brightness of Thin Disk Lasers. To achieve a wide locking range from threshold until maximum operation current (for example from 30A to 250A), careful control of laser system alignment is necessary to ensure effective feedback and locking, without using strong gratings which could reduce laser efficiency. For this purpose, we use wavefront correction optics to compensate for laser bar smile and Fast Axis Collimation pointing errors. We reduce the pointing errors from ~ 1 mrad to an average under 0.1 mrad across the bar and across the entire stack. Time resolved spectra are used to investigate the dynamic locking behavior with the goal of achieving a locking speed comparable to the rise time of the current (100 ?s). Experimental results for multi-kW laser systems are presented, both in CW and soft pulsed operation modes.

Negoita, Viorel C.; Li, Yufeng; Barnowski, Tobias; Jiang, John; An, Haiyan; Roff, Robert; Shih, Ming; Vethake, Thilo; Gottwald, Tina; Schad, Sven; Treusch, Georg

2014-03-01

48

Recombination Ghosts in Littrow Configuration: Implications for Spectrographs Using Volume Phase Holographic Gratings  

E-print Network

We report the discovery of optical ghosts generated when using Volume Phase Holographic (VPH) gratings in spectrographs employing the Littrow configuration. The ghost is caused by light reflected off the detector surface, recollimated by the camera, recombined by, and reflected from, the grating and reimaged by the camera onto the detector. This recombination can occur in two different ways. We observe this ghost in two spectrographs being developed by the University of Wisconsin - Madison: the Robert Stobie Spectrograph for the Southern African Large Telescope and the Bench Spectrograph for the WIYN 3.5m telescope. The typical ratio of the brightness of the ghost relative to the integrated flux of the spectrum is of order 10^-4, implying a recombination efficiency of the VPH gratings of order 10^-3 or higher, consistent with the output of rigorous coupled wave analysis. Any spectrograph employing VPH gratings, including grisms, in Littrow configuration will suffer from this ghost, though the general effect is not intrinsic to VPH gratings themselves and has been observed in systems with conventional gratings in non-Littrow configurations. We explain the geometric configurations that can result in the ghost as well as a more general prescription for predicting its position and brightness on the detector. We make recommendations for mitigating the ghost effects for spectrographs and gratings currently built. We further suggest design modifications for future VPH gratings to eliminate the problem entirely, including tilted fringes and/or prismatic substrates. We discuss the resultant implications on the spectrograph performance metrics.

Eric B. Burgh; Matthew A. Bershady; Kyle B. Westfall; Kenneth H. Nordsieck

2007-08-02

49

Progress in read-write fast-access volume holographic data storage  

NASA Astrophysics Data System (ADS)

We review recent progress made towards commercializable read-write, fast-access holographic data storage. This includes a recent demonstration of high areal density holographic storage, systems architectures for extending this high density to high capacity using phase-conjugate readout, and recent experimental progress along these lines. Other topics include using signal processing to relieve alignment and distortion constraints, optical elements for improving beam uniformity, and most importantly, requirements and prospects for improved photorefractive materials for two-color, gated nonvolatile holographic storage.

Burr, Geoffrey W.; Mecher, Erwin; Juchem, Thorsten; Coufal, Hans J.; Jefferson, C. Michael; Jurich, Mark C.; Gallego, Francisco; Meerholz, Klaus; Hampp, Norbert A.; Hoffnagle, John A.; Macfarlane, Roger M.; Shelby, Robert M.

2002-01-01

50

Optical design for a spatial-spectral volume holographic imaging system  

E-print Network

The spatial-spectral holographic imaging system (S[superscript 2]-VHIS) is a promising alternative to confocal microscopy due to its capabilities to simultaneously image several sample depths with high resolution. However, ...

Gelsinger-Austin, Paul J.

51

From the surface to volume: concepts for the next generation of optical-holographic data-storage materials.  

PubMed

Optical data storage has had a major impact on daily life since its introduction to the market in 1982. Compact discs (CDs), digital versatile discs (DVDs), and Blu-ray discs (BDs) are universal data-storage formats with the advantage that the reading and writing of the digital data does not require contact and is therefore wear-free. These formats allow convenient and fast data access, high transfer rates, and electricity-free data storage with low overall archiving costs. The driving force for development in this area is the constant need for increased data-storage capacity and transfer rate. The use of holographic principles for optical data storage is an elegant way to increase the storage capacity and the transfer rate, because by this technique the data can be stored in the volume of the storage material and, moreover, it can be optically processed in parallel. This Review describes the fundamental requirements for holographic data-storage materials and compares the general concepts for the materials used. An overview of the performance of current read-write devices shows how far holographic data storage has already been developed. PMID:21538730

Bruder, Friedrich-Karl; Hagen, Rainer; Rölle, Thomas; Weiser, Marc-Stephan; Fäcke, Thomas

2011-05-01

52

The infrared imaging spectrograph (IRIS) for TMT: volume phase holographic grating performance testing and discussion  

NASA Astrophysics Data System (ADS)

Maximizing the grating efficiency is a key goal for the first light instrument IRIS (Infrared Imaging Spectrograph) currently being designed to sample the diffraction limit of the TMT (Thirty Meter Telescope). Volume Phase Holographic (VPH) gratings have been shown to offer extremely high efficiencies that approach 100% for high line frequencies (i.e., 600 to 6000l/mm), which has been applicable for astronomical optical spectrographs. However, VPH gratings have been less exploited in the near-infrared, particularly for gratings that have lower line frequencies. Given their potential to offer high throughputs and low scattered light, VPH gratings are being explored for IRIS as a potential dispersing element in the spectrograph. Our team has procured near-infrared gratings from two separate vendors. We have two gratings with the specifications needed for IRIS current design: 1.51-1.82?m (H-band) to produce a spectral resolution of 4000 and 1.19-1.37?m (J-band) to produce a spectral resolution of 8000. The center wavelengths for each grating are 1.629?m and 1.27?m, and the groove densities are 177l/mm and 440l/mm for H-band R=4000 and J-band R=8000, respectively. We directly measure the efficiencies in the lab and find that the peak efficiencies of these two types of gratings are quite good with a peak efficiency of ~88% at the Bragg angle in both TM and TE modes at H-band, and 90.23% in TM mode, 79.91% in TE mode at J-band for the best vendor. We determine the drop in efficiency off the Bragg angle, with a 20-23% decrease in efficiency at H-band when 2.5° deviation from the Bragg angle, and 25%-28% decrease at J-band when 5° deviation from the Bragg angle.

Chen, Shaojie; Meyer, Elliot; Wright, Shelley A.; Moore, Anna M.; Larkin, James E.; Maire, Jerome; Mieda, Etsuko; Simard, Luc

2014-07-01

53

Combined volume phase holographic gratings used as a beam splitter in near-infrared waveband  

NASA Astrophysics Data System (ADS)

With the intrinsic advantages of high diffraction efficiency, signal to noise ratio, wavelength and angle selectivity, and low scattering and absorption, volume phase holographic gratings (VPHGs) have been widely used for spectroscopy, telecommunications, astronomy and ultra-fast sciences. In this paper, a novel kind of beam splitter which is consisted of a transmission VPHG and a reflection VPHG as core components and used in near-infrared waveband is proposed. The design idea of the device is described in detail. Based on the Bragg condition and the rigorous coupled wave analysis (RCWA), diffraction properties in near-infrared waveband of the transmission and reflection VPHGs recorded in dichromated gelatin (DCG) are studied theoretically. As an example, two wavebands that need to be separated in near infrared spectrum region are taken into account. One that from 1.574?m to 1.617?m centered at 1.596?m will be diffracted by the reflection grating, and the other that from 1.636?m to 1.682?m centered at 1.659?m will be diffracted by the transmission grating. The diffraction efficiencies of the gratings are calculated and optimized by applying Kogelnik's coupled wave theory and G-solver software, respectively. The recording setup is also designed for further experiments. The effects of the recording and reconstruction setup parameters, the amplitude of the index modulation (?n) and the thickness of the gelatin layer (d), and the polarization state of reconstruction beams on the diffraction efficiency properties of the gratings are calculated and analyzed. This kind of beam splitter is prospected to be used in spectrometers for greenhouse gases monitoring.

Zhang, Xizhao; Mei, Qijing; Tang, Minxue

2014-11-01

54

Locking and wavelength selection of an ultra-collimated single-mode diode laser bar by a volume holographic grating.  

PubMed

Wavelength-locking by a volume holographic grating (VHG) is reported for a diode laser bar with 49 single mode emitters, fitted with a dual-axis collimation phase-plate for smile elimination and excellent beam pointing correction. The much-improved VHG feedback with the ultra-collimated array beam gives 100% wavelength locking at 975 nm over a 17°C temperature range and external cavity lengths up to 110 mm. This enables a folded cavity configuration to provide a fully-locked array with wavelength selection into 200 pm channels over an 8 nm band, suitable for multi-bar dense wavelength-combining. PMID:23481984

Trela, Natalia; Baker, Howard J; Hall, Denis R

2013-02-25

55

Holographic explanation of wide-angle power correlation suppression in the Cosmic Microwave Background Radiation  

E-print Network

We investigate the question of the suppression of the CMB power spectrum for the lowest multipoles in closed Universes. The intrinsic reason for a lowest cutoff in closed Universes, connected with the discrete spectrum of the wavelength, is shown not to be enough to explain observations. We thus extend the holographic cosmic duality to closed universes by relating the dark energy equation of state and the power spectrum, showing a suppression behavior which describes the low l features extremely well. We also explore the possibility to disclose the nature of the dark energy from the observed small l CMB spectrum by employing the holographic idea.

Zhuo-Yi Huang; Bin Wang; Elcio Abdalla; Ru-Keng Su

2006-04-21

56

Synthesis of DMAW-PMMA photopolymer with high photosensitivity for volume holographic storage  

NASA Astrophysics Data System (ADS)

Holographic storage has been considered as a promising candidate for high density data storage because of its potential for terabyte capacity and high data transfer rate. However, lack of a suitable recording material obstructs further development of holographic storage. Photopolymer material has been demonstrated to be the most attractive recording media due to its advantages of high diffraction efficiency, large dynamic range and low cost. Phenanthraquinone (PQ) doped poly (methyl methacrylate) (PMMA) has attracted much attention due to negligible shrinkage and high refractive index modulation. However, the photosensitivity for holographic recording has been limited by the low solubility of the photosensitizer PQ in methyl methacrylate (MMA). Compared to PQ, (2E,5E)-2,5-bis[ 4-(dimethylamino)-phenyl]methylene]-cyclopentanone (DMAW) has a higher solubility and higher absorption at the wavelength of 532nm. By doping photosensitive system consisting of photosensitizer DMAW and photoinitiator 1,1',2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenyl-bisimidazole (o-cl-HABI) into PMMA, a novel photopolymer with high photo-sensitivity was fabricated by using injection molding technology. The properties of the spectral absorption and the holographic grating dynamic recording are presented. The results show that the photosensitivity of the photopolymer is greatly improved compared to PQ-PMMA with the largest concentration of PQ doped. The optimized concentration of photoinitiator is about 1 wt.%. The feasibility of applying this new photopolymer to holographic storage of images is experimentally demonstrated.

Li, Jingming; Cao, Liangcai; Li, Chengmingyue; He, Qingsheng; Jin, Guofan

2012-10-01

57

Optical memory development. Volume 2: Gain-assisted holographic storage media  

NASA Technical Reports Server (NTRS)

Thin deformable films were investigated for use as the storage medium in a holographic optical memory. The research was directed toward solving the problems of material fatigue, selective heat addressing, electrical charging of the film surface and charge patterning by light. A number of solutions to these problems were found but the main conclusion to be drawn from the work is that deformable media which employ heat in the recording process are not satisfactory for use in a high-speed random-access read/write holographic memory. They are, however, a viable approach in applications where either high speed or random-access is not required.

Gange, R. A.; Mezrich, R. S.

1972-01-01

58

Optimisation of a Stirred Bioreactor through the Use of a Novel Holographic Correlation Velocimetry Flow Measurement Technique  

PubMed Central

We describe a method for measuring three dimensional (3D) velocity fields of a fluid at high speed, by combining a correlation-based approach with in-line holography. While this method utilizes tracer particles contained within the flow, our method does not require the holographic reconstruction of 3D images. The direct flow reconstruction approach developed here allows for measurements at seeding densities in excess of the allowable levels for techniques based on image or particle reconstruction, thus making it suited for biological flow measurement, such as the flow in bioreactor. We outline the theory behind our method, which we term Holographic Correlation Velocimetry (HCV), and subsequently apply it to both synthetic and laboratory data. Moreover, because the system is based on in-line holography, it is very efficient with regard to the use of light, as it does not rely on side scattering. This efficiency could be utilized to create a very high quality system at a modest cost. Alternatively, this efficiency makes the system appropriate for high-speed flows and low exposure times, which is essential for imaging dynamic systems. PMID:23776534

Ismadi, Mohd-Zulhilmi; Higgins, Simon; Samarage, Chaminda R.; Paganin, David; Hourigan, Kerry; Fouras, Andreas

2013-01-01

59

Holographic and Speckle Interferometry  

NASA Astrophysics Data System (ADS)

Preface to the first edition; Preface to the second edition; 1. Basic optical principles; 2. Holographic interferometry; 3. Speckle pattern interferometry; 4. Electronic speckle pattern correlation interferometry; 5. Holographic and speckle pattern interferometry techniques for shape measurements; 6. Experimental design and technique; 7. Applications; Appendices; References; Index.

Jones, Robert; Wykes, Catherine

1989-01-01

60

Vector-axial vector correlators in weak electric field and the holographic dynamics of the chiral condensate  

NASA Astrophysics Data System (ADS)

The transverse part of the vector-axial vector flavor current correlator in the presence of weak external electric field is studied using holography. The correlator is calculated using a bottom-up model proposed recently , that includes both contributions of higher string states and the non-linear dynamics of the chiral condensate. It is shown that for low momenta the result agrees with the relation proposed by Son and Yamamoto motivated by a simpler holographic model. This suggests that the Son-Yamamoto relation is generically valid in the IR of models with the proper chiral symmetry breaking pattern.

Iatrakis, Ioannis; Kiritsis, Elias

2012-02-01

61

Associative recall in a volume holographic storage system based on phase-code multiplexing  

Microsoft Academic Search

.   We present two different techniques on how to realize a content-addressed holographic memory when using phase-code multiplexing,\\u000a relying on simple intensity measurements rather than phase distributions. Theoretical and experimental results of associative\\u000a recall in a phase-coded system designed for digital data storage will be presented and compared to the corresponding method\\u000a when using angular multiplexing.

G. Berger; C. Denz; S. S. Orlov; B. Phillips; L. Hesselink

2001-01-01

62

Signal Correlation with Phase-Conjugate Holographic Reconstruction Using a BaTiO3 Crystal  

NASA Astrophysics Data System (ADS)

An experimental demonstration is presented of a new optically implemented analog method which generates the correlation function of a reference rf signal and a continuous signal input. A reference signal input into an acousto-optic cell produces an index-of-refraction pattern. A coherent pulse input into the cell is modulated by the index pattern. This optical pulse, phase modulated by the index pattern, is directed into a BaTiO3 crystal and recorded there as a volume phase hologram. At this point a second input into the cell produces a second, moving, index-of-refraction pattern in the cell. A second optical input passing through the cell generates a phase-conjugate reconstruction of the original optical field, that of the pulse diffracted by the reference index pattern. The conjugate field propagates back through the cell, where it is diffracted by the moving pattern. The back-propagating cell output is collected by a spherical lens. There is a variation in intensity at the focus, as the moving index pattern shifts with respect to the stationary reconstruction. This variation, a function of the shift, is the correlation function of the two signals.

Brody, Philip S.

1986-06-01

63

Correlations between elastic moduli and molar volume in metallic glasses  

SciTech Connect

We report clear correlations between bulk modulus (K) and average molar volume V{sub m}, and between Poisson's ratio {nu} and V{sub m} for various bulk metallic glasses. The origin for the correlations between elastic moduli and V{sub m} are discussed. The established correlation, associated with Poisson's ratio {nu}, and since the {nu} correlates with plasticity of metallic glasses, indicates that the average molar volume is important factor to be considered for plastic metallic glasses searching. The found correlations also suggest a close relation between the mechanical properties and the short-range atomic bonding, and assist in understanding deformation behavior in metallic glasses.

Wang, J. Q.; Wang, W. H.; Yu, H. B.; Bai, H. Y. [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2009-03-23

64

Imaging bacterial 3D motion using digital in-line holographic microscopy and correlation-based de-noising algorithm.  

PubMed

Better understanding of bacteria environment interactions in the context of biofilm formation requires accurate 3-dimentional measurements of bacteria motility. Digital Holographic Microscopy (DHM) has demonstrated its capability in resolving 3D distribution and mobility of particulates in a dense suspension. Due to their low scattering efficiency, bacteria are substantially difficult to be imaged by DHM. In this paper, we introduce a novel correlation-based de-noising algorithm to remove the background noise and enhance the quality of the hologram. Implemented in conjunction with DHM, we demonstrate that the method allows DHM to resolve 3-D E. coli bacteria locations of a dense suspension (>107 cells/ml) with submicron resolutions (<0.5 µm) over substantial depth and to obtain thousands of 3D cell trajectories. PMID:25607177

Molaei, Mehdi; Sheng, Jian

2014-12-29

65

Anatomical and functional correlates of human hippocampal volume asymmetry  

PubMed Central

Hemispheric asymmetry of the human hippocampus is well established, but poorly understood. We studied 110 healthy subjects with 3-Tesla MRI to explore the anatomical and functional correlates of the R>L volume asymmetry. We found that the asymmetry is limited to the anterior hippocampus (hemisphere × region interaction: F(1,109) = 42.6, p < .001). Anterior hippocampal volume was correlated strongly with the volumes of all four cortical lobes. In contrast, posterior hippocampal volume was correlated strongly only with occipital lobe volume, moderately with the parietal and temporal lobe volumes and not with the frontal lobe volume. The degree of R>L anterior hippocampal volume asymmetry predicted performance on a measure of basic cognitive abilities. This provides evidence for regional specificity and functional implications of the well-known hemispheric asymmetry of hippocampal volume. We suggest that the developmental profile, genetic mechanisms and functional implications of R>L anterior hippocampal volume asymmetry in the human brain deserve further study. PMID:22285719

Woolard, Austin; Heckers, Stephan

2011-01-01

66

Evaluation of spatial-spectral filtering in non-paraxial volume holographic imaging systems  

E-print Network

In this thesis, the properties of transmission-mode volume phase holograms as spatial-spectral filters in optical systems for microscopic medical imaging are evaluated. In experiment, the relationship between the angle of ...

Watson, Jonathan M

2008-01-01

67

Strongly correlated quantum fluids: ultracold quantum gases, quantum chromodynamic plasmas and holographic duality  

E-print Network

Strongly correlated quantum fluids are phases of matter that are intrinsically quantum mechanical and that do not have a simple description in terms of weakly interacting quasiparticles. Two systems that have recently ...

Adams, Allan

68

High-speed holographic correlation system for video identification on the internet  

NASA Astrophysics Data System (ADS)

Automatic video identification is important for indexing, search purposes, and removing illegal material on the Internet. By combining a high-speed correlation engine and web-scanning technology, we developed the Fast Recognition Correlation system (FReCs), a video identification system for the Internet. FReCs is an application thatsearches through a number of websites with user-generated content (UGC) and detects video content that violates copyright law. In this paper, we describe the FReCs configuration and an approach to investigating UGC websites using FReCs. The paper also illustrates the combination of FReCs with an optical correlation system, which is capable of easily replacing a digital authorization sever in FReCs with optical correlation.

Watanabe, Eriko; Ikeda, Kanami; Kodate, Kashiko

2013-12-01

69

Content-addressable holographic databases  

Microsoft Academic Search

Holographic data storage allows the simultaneous search of an entire database by performing multiple optical correlations between stored data pages and a search argument. We have recently developed fuzzy encoding techniques for this fast parallel search and demonstrated a holographic data storage system that searches digital data records with high fidelity. This content-addressable retrieval is based on the ability to

Felix Grawert; Sebastian Kobras; Geoffrey W. Burr; Hans J. Coufal; Holger Hanssen; Marc Riedel; C. M. Jefferson; Mark C. Jurich

2000-01-01

70

Holographic Calculations of Euclidean Wilson Loop Correlator in Euclidean anti-de Sitter Space  

E-print Network

The correlation functions of two or more Euclidean Wilson loops of various shapes in Euclidean anti-de Sitter space are computed by considering the minimal area surfaces connecting the loops. The surfaces are parametrized by Riemann theta functions associated with genus three hyperelliptic Riemann surfaces. In the case of two loops, the distance $L$ by which they are separated can be adjusted by continuously varying a specific branch point of the auxiliary Riemann surface. When $L$ is much larger than the characteristic size of the loops, then the loops are approximately regarded as local operators and their correlator as the correlator of two local operators. Similarly, when a loop is very small compared to the size of another loop, the small loop is considered as a local operator corresponding to a light supergravity mode.

Sannah Ziama

2015-01-12

71

Holographic Calculations of Euclidean Wilson Loop Correlator in Euclidean anti-de Sitter Space  

E-print Network

The correlation functions of two or more Euclidean Wilson loops of various shapes in Euclidean anti-de Sitter space are computed by considering the minimal area surfaces connecting the loops. The surfaces are parametrized by Riemann theta functions associated with genus three hyperelliptic Riemann surfaces. In the case of two loops, the distance $L$ by which they are separated can be adjusted by continuously varying a specific branch point of the auxiliary Riemann surface. When $L$ is much larger than the characteristic size of the loops, then the loops are approximately regarded as local operators and their correlator as the correlator of two local operators. Similarly, when a loop is very small compared to the size of another loop, the small loop is considered as a local operator corresponding to a light supergravity mode.

Ziama, Sannah

2015-01-01

72

Finite volume form factors and correlation functions at finite temperature  

E-print Network

In this thesis we investigate finite size effects in 1+1 dimensional integrable QFT. In particular we consider matrix elements of local operators (finite volume form factors) and vacuum expectation values and correlation functions at finite temperature. In the first part of the thesis we give a complete description of the finite volume form factors in terms of the infinite volume form factors (solutions of the bootstrap program) and the S-matrix of the theory. The calculations are correct to all orders in the inverse of the volume, only exponentially decaying (residual) finite size effects are neglected. We also consider matrix elements with disconnected pieces and determine the general rule for evaluating such contributions in a finite volume. The analytic results are tested against numerical data obtained by the truncated conformal space approach in the Lee-Yang model and the Ising model in a magnetic field. In a separate section we also evaluate the leading exponential correction (the $\\mu$-term) associated to multi-particle energies and matrix elements. In the second part of the thesis we show that finite volume factors can be used to derive a systematic low-temperature expansion for correlation functions at finite temperature. In the case of vacuum expectation values the series is worked out up to the third non-trivial order and a complete agreement with the LeClair-Mussardo formula is observed. A preliminary treatment of the two-point function is also given by considering the first nontrivial contributions.

Balázs Pozsgay

2009-07-24

73

Application of the fast-Fourier-transform-based volume integral equation method to model volume diffraction in shift-multiplexed holographic data storage  

NASA Astrophysics Data System (ADS)

Numerical simulation of diffraction on thick holographic gratings in shift-multiplexed optical data storage application is presented. The grating is generated by the interference of a spherical reference wave and a plane signal wave corresponding to a single pixel of the input data page. To describe diffraction on this weak-index-modulated grating, we use the volume integral equation in the first Born approximation. This description yields a convolution integral that can be efficiently evaluated by a 3D fast Fourier transform (FFT) technique. For a 51.2?m recording layer thickness, a serial-divided single personal computer code was built based on parallel FFT coding principles. Diffracted electric field and Poynting-vector distributions are calculated for probe beams spatially shifted with respect to the reference beams. The shift selectivity curves show significant differences from previous analytical calculations based on paraxial propagation and infinite gratings, as they have monotonic decrease in all three directions instead of sinclike functions with Bragg nulls. With the chosen numerical aperture of 0.6 and linear polarization, both the scalar and vector calculations provided similar results within 5%.

Gombköt?, Balázs; Koppa, Pál; Maák, Pál; L?rincz, Em?ke

2006-11-01

74

Performance analysis of the FDTD method applied to holographic volume gratings: Multi-core CPU versus GPU computing  

NASA Astrophysics Data System (ADS)

The finite-difference time-domain method (FDTD) allows electromagnetic field distribution analysis as a function of time and space. The method is applied to analyze holographic volume gratings (HVGs) for the near-field distribution at optical wavelengths. Usually, this application requires the simulation of wide areas, which implies more memory and time processing. In this work, we propose a specific implementation of the FDTD method including several add-ons for a precise simulation of optical diffractive elements. Values in the near-field region are computed considering the illumination of the grating by means of a plane wave for different angles of incidence and including absorbing boundaries as well. We compare the results obtained by FDTD with those obtained using a matrix method (MM) applied to diffraction gratings. In addition, we have developed two optimized versions of the algorithm, for both CPU and GPU, in order to analyze the improvement of using the new NVIDIA Fermi GPU architecture versus highly tuned multi-core CPU as a function of the size simulation. In particular, the optimized CPU implementation takes advantage of the arithmetic and data transfer streaming SIMD (single instruction multiple data) extensions (SSE) included explicitly in the code and also of multi-threading by means of OpenMP directives. A good agreement between the results obtained using both FDTD and MM methods is obtained, thus validating our methodology. Moreover, the performance of the GPU is compared to the SSE+OpenMP CPU implementation, and it is quantitatively determined that a highly optimized CPU program can be competitive for a wider range of simulation sizes, whereas GPU computing becomes more powerful for large-scale simulations.

Francés, J.; Bleda, S.; Neipp, C.; Márquez, A.; Pascual, I.; Beléndez, A.

2013-03-01

75

Weak correlation of starch and volume in synchronized photosynthetic cells.  

PubMed

In cultures of unicellular algae, features of single cells, such as cellular volume and starch content, are thought to be the result of carefully balanced growth and division processes. Single-cell analyses of synchronized photoautotrophic cultures of the unicellular alga Chlamydomonas reinhardtii reveal, however, that the cellular volume and starch content are only weakly correlated. Likewise, other cell parameters, e.g., the chlorophyll content per cell, are only weakly correlated with cell size. We derive the cell size distributions at the beginning of each synchronization cycle considering growth, timing of cell division and daughter cell release, and the uneven division of cell volume. Furthermore, we investigate the link between cell volume growth and starch accumulation. This work presents evidence that, under the experimental conditions of light-dark synchronized cultures, the weak correlation between both cell features is a result of a cumulative process rather than due to asymmetric partition of biomolecules during cell division. This cumulative process necessarily limits cellular similarities within a synchronized cell population. PMID:25679646

Rading, M Michael; Sandmann, Michael; Steup, Martin; Chiarugi, Davide; Valleriani, Angelo

2015-01-01

76

Cross-correlations between volume change and price change.  

PubMed

In finance, one usually deals not with prices but with growth rates R, defined as the difference in logarithm between two consecutive prices. Here we consider not the trading volume, but rather the volume growth rate R, the difference in logarithm between two consecutive values of trading volume. To this end, we use several methods to analyze the properties of volume changes |R|, and their relationship to price changes |R|. We analyze 14,981 daily recordings of the Standard and Poor's (S & P) 500 Index over the 59-year period 1950-2009, and find power-law cross-correlations between |R| and |R| by using detrended cross-correlation analysis (DCCA). We introduce a joint stochastic process that models these cross-correlations. Motivated by the relationship between |R| and |R|, we estimate the tail exponent alpha of the probability density function P(|R|) approximately |R|(-1-alpha) for both the S & P 500 Index as well as the collection of 1819 constituents of the New York Stock Exchange Composite Index on 17 July 2009. As a new method to estimate alpha, we calculate the time intervals tau(q) between events where R > q. We demonstrate that tau(q), the average of tau(q), obeys tau(q) approximately q(alpha). We find alpha approximately 3. Furthermore, by aggregating all tau(q) values of 28 global financial indices, we also observe an approximate inverse cubic law. PMID:20018772

Podobnik, Boris; Horvatic, Davor; Petersen, Alexander M; Stanley, H Eugene

2009-12-29

77

Amygdala volume correlates positively with fearfulness in normal healthy girls.  

PubMed

Research into the neural underpinnings of fear and fear-related pathology has highlighted the role of the amygdala. For instance, bilateral damage to the amygdaloid complex is associated with decreased appreciation of danger and recognition of fear in humans, whereas enlarged amygdala volume is associated with internalizing syndromes. It is unknown whether amygdala volume and fearfulness are related in the absence of pathology. We examined the correlation between normal fearfulness and amygdala morphology in 116 healthy children and adolescents (60 boys, 56 girls, age 7-17 years). Fearfulness was measured using the parent ratings on the Pediatric Behavior Scale and amygdala volumes were determined by manual tracing. We found a positive correlation between right amygdala volume in girls (r = 0.29). This relationship was more robust and present bilaterally when analyses were limited to girls with a positive nuclear family history of depression (for left r = 0.63; for right r = 0.58). In boys there was no significant relationship which may suggest that biological mechanisms differ between sexes. Given the role of enlarged amygdala volume in pathology, these findings may indicate that variation in amygdala morphology marks susceptibility to internalizing disorders. PMID:20150341

van der Plas, Ellen A A; Boes, Aaron D; Wemmie, John A; Tranel, Daniel; Nopoulos, Peg

2010-12-01

78

Heavy quark correlations and the effective volume for quarkonia production  

E-print Network

Using the Boltzmann transport approach, we study the effective volume of a correlated heavy quark pair in a partonic medium based on their collision rate. We find that the effective volume is finite and depends sensitively on the momentum of the heavy quark and the temperature of the medium. Generally, it increases linearly with time $t$ at the very beginning and the increase then becomes slower due to multiple scattering, and finally it increases linearly with respect to $t^{3/2}$. We further find that the colliding heavy quark pair has an effective temperature similar to that of the medium even though their initial transverse momentum spectra are far from thermal equilibrium.

Yunpeng Liu; Che Ming Ko; Feng Li

2014-06-25

79

Limitations of phase-conjugate replay in volume-holographic phase-disturbing media.  

PubMed

We examine the consequences of permanent phase distortions on the replay of transmission volume holograms with a phase-conjugated reference wave. In the absence of Bragg degeneracies and significant Bragg mismatch, for negligible dispersion in the spatial frequency response and for negligible variation in obliquity, phase-conjugated reference waves compensate for the effects of phase distortions and permit cross-talk-free multiplexing by using orthogonal reference waves. Spatial frequency dispersion, however, is a source of image distortion and cross talk. PMID:19802258

Bashaw, M C; Aharoni, A; Hesselink, L

1993-05-01

80

Volume phase holographic gratings for the Subaru Prime Focus Spectrograph: performance measurements of the prototype grating set  

NASA Astrophysics Data System (ADS)

The Prime Focus Spectrograph (PFS) is a major instrument under development for the 8.2 m Subaru telescope on Mauna Kea. Four identical, fixed spectrograph modules are located in a room above one Nasmyth focus. A 55 m fiber optic cable feeds light into the spectrographs from a robotic fiber positioner mounted at the telescope prime focus, behind the wide field corrector developed for Hyper Suprime-Cam. The positioner contains 2400 fibers and covers a 1.3 degree hexagonal field of view. Each spectrograph module will be capable of simultaneously acquiring 600 spectra. The spectrograph optical design consists of a Schmidt collimator, two dichroic beamsplitters to separate the light into three channels, and for each channel a volume phase holographic (VPH) grating and a dual- corrector, modified Schmidt reimaging camera. This design provides a 275 mm collimated beam diameter, wide simultaneous wavelength coverage from 380 nm to 1.26 µm, and good imaging performance at the fast f/1.1 focal ratio required from the cameras to avoid oversampling the fibers. The three channels are designated as the blue, red, and near-infrared (NIR), and cover the bandpasses 380-650 nm (blue), 630-970 nm (red), and 0.94-1.26 µm (NIR). A mosaic of two Hamamatsu 2k×4k, 15 µm pixel CCDs records the spectra in the blue and red channels, while the NIR channel employs a 4k×4k, substrate-removed HAWAII-4RG array from Teledyne, with 15 µm pixels and a 1.7 µm wavelength cutoff. VPH gratings have become the dispersing element of choice for moderate-resolution astronomical spectro- graphs due their potential for very high diffraction efficiency, low scattered light, and the more compact instru- ment designs offered by transmissive dispersers. High quality VPH gratings are now routinely being produced in the sizes required for instruments on large telescopes. These factors made VPH gratings an obvious choice for PFS. In order to reduce risk to the project, as well as fully exploit the performance potential of this technology, a set of three prototype VPH gratings (one each of the blue, red, and NIR designs) was ordered and has been recently delivered. The goal for these prototype units, but not a requirement, was to meet the specifications for the final gratings in order to serve as spares and also as early demonstration and integration articles. In this paper we present the design and specifications for the PFS gratings, the plan and setups used for testing both the prototype and final gratings, and results from recent optical testing of the prototype grating set.

Barkhouser, Robert H.; Arns, James; Gunn, James E.

2014-08-01

81

Holographic sundial.  

PubMed

A holographic sundial, to our knowledge the first sundial that does not use a gnomen or shadow-casting device, is designed and demonstrated. The accuracy of the device is measured and analyzed. PMID:19770955

Penland, R; Cormack, R; Carsten, J; Sayhun, S; Johnson, K M

1990-09-01

82

Gas-sensitive holographic sensors  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 4.38 Holographic response to atmospheric gases at different temperatures. 94 4.39 Holographic response versus temperature for all gaseous hydrocar- bons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 4.40 Correlation... in the stratosphere differ from those in other atmo- spheric layers [2–4]. In fact, with industrialization and increased consumption of gas products for daily use, certain gas molecules accumulate in cities and indoor environments [5]. Numerous human activities...

Martínez Hurtado, Juan Leonardo

2013-04-16

83

Holographic meson melting  

Microsoft Academic Search

The plasma phase at high temperatures of a strongly coupled gauge theory can be holographically modelled by an AdS black hole. Matter in the fundamental representation and in the quenched approximation is introduced through embedding D7-branes in the AdS-Schwarzschild background. Low spin mesons correspond to the fluctuations of the D7-brane world volume. As is well known by now, there are

Carlos Hoyos; Karl Landsteiner; Sergio Montero

2007-01-01

84

Soft limits in holographic cosmology  

NASA Astrophysics Data System (ADS)

We study the soft limits of cosmological correlators from a holographic perspective, showing how the inflationary consistency relations arise from the diffeomorphism invariance of the dual quantum field theory. Starting from the corresponding Ward identity, by taking moments we derive the leading and subleading behaviour of the stress tensor 3-point function in the limit as one momentum vanishes. These results are non-perturbative and valid in quantum field theories of a very general nature. Exploiting the known mapping of correlators in the dual quantum field theory to those of the cosmology, we then obtain the leading and subleading soft behaviour of all cosmological 3-point correlators of curvature perturbations and gravitons. Our results thus provide a holographic derivation of all leading and subleading consistency relations for cosmological 3-point functions, and our method is easily generalised. We verify our results explicitly for slow-roll inflation and for strongly coupled holographic cosmologies with a perturbative dual description.

McFadden, Paul

2015-02-01

85

Extreme-ultraviolet Bragg holographic structures: theory and experiments  

SciTech Connect

A theoretical analysis of extreme-ultraviolet (XUV) Bragg (volume) holographic diffraction structures with arbitrary periodic spatial-modulation profiles is presented, and two basic approaches for the fabrication of XUV holographic optical elements suggested by the theory are discussed. The theoretical results are compared with preliminary experimental observations from XUV Bragg holographic structures recently fabricated in the laboratory, and fairly good agreement is found. This comparison indicates that our holographic materials can reach very high refractive-index modulation ({Delta}n{similar to}0.4) and are thus good candidates for the production of high-efficiency XUV holographic optical elements.

Jannson, T.; Savant, G.; Wang, L. (Physical Optics Corporation, Suite 103, 20600 Gramercy Place, Torrance, California (USA))

1991-10-01

86

Holographic pomeron  

NASA Astrophysics Data System (ADS)

This thesis discusses the approach to hadronic scattering at high energies and the description of the pomeron within holographic QCD. Based on a stringy Schwinger mechanism in curved space, the pomeron emerges through the exchange of closed strings between two dipoles and yields Regge behavior for the elastic scattering amplitude. Our holographic result for the dipole-dipole cross section and the wee-dipole density in the conformal limit are shown to be identical in form to the BFKL pomeron result when the non-critical string transverse dimension is D_?=3. Thus, we have obtained an evolution for the wee-dipole density as a function of both rapidity, impact parameter and virtuality. The open string picture allows us to define a local Unruh temperature associated to the scattering process, which is large as the impact parameter is large but small compared to the Hagedorn temperature. Associated with the temperature on the boundary, the Unruh temperature allows us to define the free energy of the system. The induced instanton on the string world-sheet carries entropy for a dipole source of N-ality "k". This stringy entropy is neither coherent nor thermal. We argue that it is released promptly over a time that is solely determined by the impact parameter and the rapidity. It may explain the 3/2 jump in the total charged multiplicities at about 10 participants reported over a wide range of collider energies by PHOBOS. We predict the charged multiplicities in pp, pA and central AA collisions at LHC. The total dipole-dipole cross section is compared to DIS data from HERA and the holographic result for the differential cross section compared to proton-proton and deeply virtual Compton scattering data. With the holographic parameters close to QCD expectations, the holographic results are in reasonable agreement with the data for a variety of observables in the Regge regime.

Stoffers, Alexander

87

Fast fluorescence holographic microscopy  

PubMed Central

FINCHSCOPE is a new technology of fluorescence holographic microscopy. It has been successfully applied to recording high-resolution three-dimensional fluorescence images of biological specimens without the need for scanning. In this study, we revealed and analyzed an intrinsic phenomenon, called ghost lens effect, on spatial light modulator which is the core element enabling the incoherent correlation in the FINCHSCOPE. The ghost lens effect can degrade the imaging quality by introducing multiple spherical waves with different focal lengths into the correlation and thus increasing the noise in the recorded holograms.

Qin, Wan; Yang, Xiaoqi; Li, Yingying; Peng, Xiang; Qu, Xinghua; Yao, Hai; Gao, Bruce Z.

2015-01-01

88

The traveltime holographic principle  

NASA Astrophysics Data System (ADS)

Fermat's interferometric principle is used to compute interior transmission traveltimes ?pq from exterior transmission traveltimes ?sp and ?sq. Here, the exterior traveltimes are computed for sources s on a boundary B that encloses a volume V of interior points p and q. Once the exterior traveltimes are computed, no further ray tracing is needed to calculate the interior times ?pq. Therefore this interferometric approach can be more efficient than explicitly computing interior traveltimes ?pq by ray tracing. Moreover, the memory requirement of the traveltimes is reduced by one dimension, because the boundary B is of one fewer dimension than the volume V. An application of this approach is demonstrated with interbed multiple (IM) elimination. Here, the IMs in the observed data are predicted from the migration image and are subsequently removed by adaptive subtraction. This prediction is enabled by the knowledge of interior transmission traveltimes ?pq computed according to Fermat's interferometric principle. We denote this principle as the `traveltime holographic principle', by analogy with the holographic principle in cosmology where information in a volume is encoded on the region's boundary.

Huang, Yunsong; Schuster, Gerard T.

2015-01-01

89

Holographic photolysis of caged neurotransmitters  

PubMed Central

Stimulation of light-sensitive chemical probes has become a powerful tool for the study of dynamic signaling processes in living tissue. Classically, this approach has been constrained by limitations of lens–based and point-scanning illumination systems. Here we describe a novel microscope configuration that incorporates a nematic liquid crystal spatial light modulator (LC-SLM) to generate holographic patterns of illumination. This microscope can produce illumination spots of variable size and number and patterns shaped to precisely match user-defined elements in a specimen. Using holographic illumination to photolyse caged glutamate in brain slices, we demonstrate that shaped excitation on segments of neuronal dendrites and simultaneous, multi-spot excitation of different dendrites enables precise spatial and rapid temporal control of glutamate receptor activation. By allowing the excitation volume shape to be tailored precisely, the holographic microscope provides an extremely flexible method for activation of various photosensitive proteins and small molecules. PMID:19160517

Lutz, Christoph; Otis, Thomas S.; DeSars, Vincent; Charpak, Serge; DiGregorio, David A.; Emiliani, Valentina

2009-01-01

90

Holographic Vitrification  

E-print Network

We establish the existence of stable and metastable stationary black hole bound states at finite temperature and chemical potentials in global and planar four-dimensional asymptotically anti-de Sitter space. We determine a number of features of their holographic duals and argue they represent structural glasses. We map out their thermodynamic landscape in the probe approximation, and show their relaxation dynamics exhibits logarithmic aging, with aging rates determined by the distribution of barriers.

Anninos, Dionysios; Denef, Frederik; Peeters, Lucas

2013-01-01

91

Price-volume cross-correlation analysis of CSI300 index futures  

NASA Astrophysics Data System (ADS)

We investigate the cross-correlation between price returns and trading volumes for the China Securities Index 300 (CSI300) index futures, which are the only stock index futures traded on the China Financial Futures Exchange (CFFEX). The basic statistics suggest that distributions of these two time series are not normal but exhibit fat tails. Based on the detrended cross-correlation analysis (DCCA), we obtain that returns and trading volumes are long-range cross-correlated. The existence of multifractality in the cross-correlation between returns and trading volumes has been proven with the multifractal detrended cross-correlation analysis (MFDCCA) algorithm. The multifractal analysis also confirms that returns and trading volumes have different degrees of multifractality. We further perform a cross-correlation statistic to verify whether the cross-correlation significantly exists between returns and trading volumes for CSI300 index futures. In addition, results of the test for lead-lag effect demonstrate that contemporaneous cross-correlation of return and trading volume series is stronger than cross-correlations of leaded or lagged series.

Wang, Dong-Hua; Suo, Yuan-Yuan; Yu, Xiao-Wen; Lei, Man

2013-03-01

92

Holographic Optical Data Storage  

NASA Technical Reports Server (NTRS)

Although the basic idea may be traced back to the earlier X-ray diffraction studies of Sir W. L. Bragg, the holographic method as we know it was invented by D. Gabor in 1948 as a two-step lensless imaging technique to enhance the resolution of electron microscopy, for which he received the 1971 Nobel Prize in physics. The distinctive feature of holography is the recording of the object phase variations that carry the depth information, which is lost in conventional photography where only the intensity (= squared amplitude) distribution of an object is captured. Since all photosensitive media necessarily respond to the intensity incident upon them, an ingenious way had to be found to convert object phase into intensity variations, and Gabor achieved this by introducing a coherent reference wave along with the object wave during exposure. Gabor's in-line recording scheme, however, required the object in question to be largely transmissive, and could provide only marginal image quality due to unwanted terms simultaneously reconstructed along with the desired wavefront. Further handicapped by the lack of a strong coherent light source, optical holography thus seemed fated to remain just another scientific curiosity, until the field was revolutionized in the early 1960s by some major breakthroughs: the proposition and demonstration of the laser principle, the introduction of off-axis holography, and the invention of volume holography. Consequently, the remainder of that decade saw an exponential growth in research on theory, practice, and applications of holography. Today, holography not only boasts a wide variety of scientific and technical applications (e.g., holographic interferometry for strain, vibration, and flow analysis, microscopy and high-resolution imagery, imaging through distorting media, optical interconnects, holographic optical elements, optical neural networks, three-dimensional displays, data storage, etc.), but has become a prominent am advertising, and security medium as well. The evolution of holographic optical memories has followed a path not altogether different from holography itself, with several cycles of alternating interest over the past four decades. P. J. van Heerden is widely credited for being the first to elucidate the principles behind holographic data storage in a 1963 paper, predicting bit storage densities on the order of 1/lambda(sup 3) with source wavelength lambda - a fantastic capacity of nearly 1 TB/cu cm for visible light! The science and engineering of such a storage paradigm was heavily pursued thereafter, resulting in many novel hologram multiplexing techniques for dense data storage, as well as important advances in holographic recording materials. Ultimately, however, the lack of such enabling technologies as compact laser sources and high performance optical data I/O devices dampened the hopes for the development of a commercial product. After a period of relative dormancy, successful applications of holography in other arenas sparked a renewed interest in holographic data storage in the late 1980s and the early 1990s. Currently, with most of the critical optoelectronic device technologies in place and the quest for an ideal holographic recording medium intensified, holography is once again considered as one of several future data storage paradigms that may answer our constantly growing need for higher-capacity and faster-access memories.

Timucin, Dogan A.; Downie, John D.; Norvig, Peter (Technical Monitor)

2000-01-01

93

Holographic enhanced remote sensing system  

NASA Technical Reports Server (NTRS)

The Holographic Enhanced Remote Sensing System (HERSS) consists of three primary subsystems: (1) an Image Acquisition System (IAS); (2) a Digital Image Processing System (DIPS); and (3) a Holographic Generation System (HGS) which multiply exposes a thermoplastic recording medium with sequential 2-D depth slices that are displayed on a Spatial Light Modulator (SLM). Full-parallax holograms were successfully generated by superimposing SLM images onto the thermoplastic and photopolymer. An improved HGS configuration utilizes the phase conjugate recording configuration, the 3-SLM-stacking technique, and the photopolymer. The holographic volume size is currently limited to the physical size of the SLM. A larger-format SLM is necessary to meet the desired 6 inch holographic volume. A photopolymer with an increased photospeed is required to ultimately meet a display update rate of less than 30 seconds. It is projected that the latter two technology developments will occur in the near future. While the IAS and DIPS subsystems were unable to meet NASA goals, an alternative technology is now available to perform the IAS/DIPS functions. Specifically, a laser range scanner can be utilized to build the HGS numerical database of the objects at the remote work site.

Iavecchia, Helene P.; Gaynor, Edwin S.; Huff, Lloyd; Rhodes, William T.; Rothenheber, Edward H.

1990-01-01

94

Holographic Charge Oscillations  

E-print Network

The Reissner-Nordstrom black hole provides the prototypical description of a holographic system at finite density. We study the response of this system to the presence of a local, charged impurity. Below a critical temperature, the induced charge density, which screens the impurity, exhibits oscillations. These oscillations can be traced to the singularities in the density-density correlation function moving in the complex momentum plane. At finite temperature, the oscillations are very similar to the Friedel oscillations seen in Fermi liquids. However, at zero temperature the oscillations in the black hole background remain exponentially damped, while Friedel oscillations relax to a power-law

Mike Blake; Aristomenis Donos; David Tong

2014-12-05

95

Holographic turbulence.  

PubMed

We construct turbulent black holes in asymptotically AdS4 spacetime by numerically solving Einstein's equations. Using the AdS/CFT correspondence we find that both the dual holographic fluid and bulk geometry display signatures of an inverse cascade with the bulk geometry being well approximated by the fluid-gravity gradient expansion. We argue that statistically steady-state black holes dual to d dimensional turbulent flows have horizons whose area growth has a fractal-like structure with fractal dimension D=d+4/3. PMID:24785028

Adams, Allan; Chesler, Paul M; Liu, Hong

2014-04-18

96

Holographic movies  

NASA Astrophysics Data System (ADS)

A unique method for the construction and display of a 3D holographic movie is developed. An animated film is produced by rotating a 3D object in steps between successive holographic exposures. Strip holograms were made on 70-mm AGFA 8E75 Holotest roll film. Each hologram was about 11-mm high and 55-mm high and 55-mm wide. The object was rotated 2 deg between successive exposures. A complete cycle of the object motion was recorded on 180 holograms using the lensless Fourier transform construction. The ends of the developed film were spliced together to produce a continuous loop. Although the film moves continuously on playback and there is not shutter, there is no flicker or image displacement because of the Fourier transform hologram construction, as predicted by the theoretical analysis. The movie can be viewed for an unlimited time because the object motion is cyclical and the film is continuous. The film is wide enough such that comfortable viewing with both eyes is possible, enhancing the 3D effect. Viewers can stand comfortably away from the film since no viewing slit or aperture is necessary. Several people can simultaneously view the movie.

Palais, Joseph C.; Miller, Mark E.

1996-09-01

97

Holographic Aquaculture  

NASA Astrophysics Data System (ADS)

Proposed is an exploratory study to verify the feasibility of an inexpensive micro-climate control system for both marine and freshwater pond and tank aquaculture, offering good control over water temperature, incident light flux, and bandwidth, combined with good energy efficiency. The proposed control system utilizes some familiar components of passive solar design, together with a new holographic glazing system which is currently being developed by, and proprietary to Advanced Environmental Research Group (AERG). The use of solar algae ponds and tanks to warm and purify water for fish and attached macroscopic marine algae culture is an ancient and effective technique, but limited seasonally and geographically by the availability of sunlight. Holographic Diffracting Structures (HDSs) can be made which passively track, accept and/or reject sunlight from a wide range of altitude and azimuth angles, and redirect and distribute light energy as desired (either directly or indirectly over water surface in an enclosed, insulated structure), effectively increasing insolation values by accepting sunlight which would not otherwise enter the structure.

Ian, Richard; King, Elisabeth

1988-01-01

98

Preterm Infant Hippocampal Volumes Correlate with Later Working Memory Deficits  

ERIC Educational Resources Information Center

Children born preterm exhibit working memory deficits. These deficits may be associated with structural brain changes observed in the neonatal period. In this study, the relationship between neonatal regional brain volumes and working memory deficits at age 2 years were investigated, with a particular interest in the dorsolateral prefrontal…

Beauchamp, Miriam H.; Thompson, Deanne K.; Howard, Kelly; Doyle, Lex W.; Egan, Gary F.; Inder, Terrie E.; Anderson, Peter J.

2008-01-01

99

Hybrid holographic non-destructive test system  

NASA Technical Reports Server (NTRS)

An automatic hybrid holographic non-destructive testing (HNDT) method and system capable of detecting flaws or debonds contained within certain materials are described. This system incorporates the techniques of optical holography, acoustical/optical holography and holographic correlation in determining the structural integrity of a test object. An automatic processing system including a detector and automatic data processor is used in conjunction with the three holographic techniques for correlating and interpreting the information supplied by the non-destructive systems. The automatic system also includes a sensor which directly translates an optical data format produced by the holographic techniques into electrical signals and then transmits this information to a digital computer for indicating the structural properties of the test object. The computer interprets the data gathered and determines whether further testing is necessary as well as the format of this new testing procedure.

Kurtz, R. L. (inventor)

1978-01-01

100

Prediction of free-volume-type correlations in glassy chalcogenides from positron annihilation lifetime measurements  

NASA Astrophysics Data System (ADS)

A newly modified correlation equation between defect-related positron lifetime determined within two-state trapping model and radius of corresponding free-volume-type defects was proposed to describe compositional variations in atomic-deficient structure of covalent-bonded chalcogenides like binary As-S/Se glasses. Specific chemical environment of free-volume voids around neighboring network-forming polyhedrons was shown to play a decisive role in this correlation, leading to systematically enhanced volumes in comparison with typical molecular substrates, such as polymers.

Shpotyuk, O.; Ingram, A.; Shpotyuk, M.; Filipecki, J.

2014-11-01

101

Nonfeedback nonlinear holographic associative memories  

NASA Astrophysics Data System (ADS)

Several original versions of nonlinearly recorded hologram- based associative memories are summarized. All of them are realized using phase-conjugate properties of such holograms being associated just with nonlinear part of a holographic recoding. The photorefractive prototypes of some represented memories are pointed out. The introduced all-optical associative memories exhibit error-correcting properties, ability to edge enhancement into associative responses, and may be realized at arbitrary recording media (thin or volume, permanent or reversible).

Polyanskii, Peter V.

1998-08-01

102

Physical Exercise Habits Correlate with Gray Matter Volume of the Hippocampus in Healthy Adult Humans  

NASA Astrophysics Data System (ADS)

Physical activity facilitates neurogenesis of dentate cells in the rodent hippocampus, a brain region critical for memory formation and spatial representation. Recent findings in humans also suggest that aerobic exercise can lead to increased hippocampal volume and enhanced cognitive functioning in children and elderly adults. However, the association between physical activity and hippocampal volume during the period from early adulthood through middle age has not been effectively explored. Here, we correlated the number of minutes of self-reported exercise per week with gray matter volume of the hippocampus using voxel-based morphometry (VBM) in 61 healthy adults ranging from 18 to 45 years of age. After controlling for age, gender, and total brain volume, total minutes of weekly exercise correlated significantly with volume of the right hippocampus. Findings highlight the relationship between regular physical exercise and brain structure during early to middle adulthood.

Killgore, William D. S.; Olson, Elizabeth A.; Weber, Mareen

2013-12-01

103

Holographic Superconductors  

E-print Network

It has been shown that a gravitational dual to a superconductor can be obtained by coupling anti-de Sitter gravity to a Maxwell field and charged scalar. We review our earlier analysis of this theory and extend it in two directions. First, we consider all values for the charge of the scalar field. Away from the large charge limit, backreaction on the spacetime metric is important. While the qualitative behaviour of the dual superconductor is found to be similar for all charges, in the limit of arbitrarily small charge a new type of black hole instability is found. We go on to add a perpendicular magnetic field B and obtain the London equation and magnetic penetration depth. We show that these holographic superconductors are Type II, i.e., starting in a normal phase at large B and low temperatures, they develop superconducting droplets as B is reduced.

Sean A. Hartnoll; Christopher P. Herzog; Gary T. Horowitz

2008-10-09

104

Holographic SQUID  

E-print Network

We propose a holographic model of the SQUID (Superconducting QUantum Interference Device) composed of two Josephson junctions connected each other in a circle with the magnetic flux penetrating the circuit of the SQUID and the supercurrents flowing in both Josephson junction. The gravity in this paper is the Einstein-Maxwell-complex scalar field model on the four-dimensional Anti-de Sitter Schwarzschild black brane geometry in which one space direction is compactified into a circle, and we arrange the profile of the coefficient of the time component of the gauge field having the role for the chemical potential of the cooper pair. The magnetic flux is involved by the rewriting of the surface integral of the magnetic field to the contour integral of the gauge field.

Takeuchi, Shingo

2013-01-01

105

Digital volume correlation analyses of synchrotron tomographic images  

E-print Network

(enriched kinematics) E Young's modulus f picture of the reference conguration g picture of the deformed hal-00624446,version1-17Sep2011 #12;List of notations a constant ap amplitude associated with mode I strains dimensionless correlation residual angle Kolossov's constant µ Lamé's modulus Poisson's ratio

Paris-Sud XI, Université de

106

Holographic tachyon model  

E-print Network

We propose in this Letter a holographic model of tachyon dark energy. A connection between the tachyon scalar-field and the holographic dark energy is established, and accordingly, the potential of the holographic tachyon field is constructed. We show that the holographic evolution of the universe with $c\\geqslant 1$ can be described completely by the resulting tachyon model in a certain way.

Jingfei Zhang; Xin Zhang; Hongya Liu

2007-06-19

107

Holographic duality in nonlinear hyperbolic metamaterials  

E-print Network

According to the holographic principle, the description of a volume of space can be thought of as encoded on its boundary. Holographic principle establishes equivalence, or duality, between theoretical description of volume physics, which involves gravity, and the gravity-free field theory, which describes physics on its surface. While generally accepted as a theoretical framework, so far there was no known experimental system which would exhibit explicit holographic duality and be amenable to direct experimental testing. Here we demonstrate that nonlinear optics of hyperbolic metamaterials admits such a dual holographic description. Wave equation which describes propagation of extraordinary light through the volume of metamaterial exhibits 2+1 dimensional Lorentz symmetry. The role of time in the corresponding effective 3D Minkowski spacetime is played by the spatial coordinate aligned with the optical axis of the material. Nonlinear optical Kerr effect bends this spacetime resulting in effective gravitational interaction between extraordinary photons. On the other hand, a holographic dual theory may be formulated on the metamaterial surface, which describes its nonlinear optics via interaction of cylindrical surface plasmons possessing conserved charges proportional to their angular momenta. Potential implications of this duality for superconductivity of hyperbolic metamaterials are discussed.

Igor I. Smolyaninov

2014-05-13

108

Holographic heat engines  

NASA Astrophysics Data System (ADS)

It is shown that in theories of gravity where the cosmological constant is considered a thermodynamic variable, it is natural to use black holes as heat engines. Two examples are presented in detail using AdS charged black holes as the working substance. We notice that for static black holes, the maximally efficient traditional Carnot engine is also a Stirling engine. The case of negative cosmological constant supplies a natural realization of these engines in terms of the field theory description of the fluids to which they are holographically dual. We first propose a precise picture of how the traditional thermodynamic dictionary of holography is extended when the cosmological constant is dynamical and then conjecture that the engine cycles can be performed by using renormalization group flow. We speculate about the existence of a natural dual field theory counterpart to the gravitational thermodynamic volume.

Johnson, Clifford V.

2014-10-01

109

Holographic Heat Engines  

E-print Network

It is shown that in theories of gravity where the cosmological constant is considered a thermodynamic variable, it is natural to use black holes as heat engines. Two examples are presented in detail using AdS charged black holes as the working substance. We notice that for static black holes, the maximally efficient traditional Carnot engine is also a Stirling engine. The case of negative cosmological constant supplies a natural realization of these engines in terms of the field theory description of the fluids to which they are holographically dual. We first propose a precise picture of how the traditional thermodynamic dictionary of holography is extended when the cosmological constant is dynamical and then conjecture that the engine cycles can be performed by using renormalization group flow. We speculate about the existence of a natural dual field theory counterpart to the gravitational thermodynamic volume.

Johnson, Clifford V

2014-01-01

110

Holographic Heat Engines  

E-print Network

It is shown that in theories of gravity where the cosmological constant is considered a thermodynamic variable, it is natural to use black holes as heat engines. Two examples are presented in detail using AdS charged black holes as the working substance. We notice that for static black holes, the maximally efficient traditional Carnot engine is also a Stirling engine. The case of negative cosmological constant supplies a natural realization of these engines in terms of the field theory description of the fluids to which they are holographically dual. We first propose a precise picture of how the traditional thermodynamic dictionary of holography is extended when the cosmological constant is dynamical and then conjecture that the engine cycles can be performed by using renormalization group flow. We speculate about the existence of a natural dual field theory counterpart to the gravitational thermodynamic volume.

Clifford V. Johnson

2014-09-04

111

Holographic Superconductors with Various Condensates  

E-print Network

We extend earlier treatments of holographic superconductors by studying cases where operators of different dimension condense in both 2+1 and 3+1 superconductors. We also compute a correlation length. We find surprising regularities in quantities such as $\\omega_g/T_c$ where $\\omega_g$ is the gap in the frequency dependent conductivity. In special cases, new bound states arise corresponding to vector normal modes of the dual near-extremal black holes.

Gary T. Horowitz; Matthew M. Roberts

2008-11-04

112

Correlated Variability in the Breathing Pattern and End-Expiratory Lung Volumes in Conscious Humans  

PubMed Central

In order to characterize the variability and correlation properties of spontaneous breathing in humans, the breathing pattern of 16 seated healthy subjects was studied during 40 min of quiet breathing using opto-electronic plethysmography, a contactless technology that measures total and compartmental chest wall volumes without interfering with the subjects breathing. From these signals, tidal volume (VT), respiratory time (TTOT) and the other breathing pattern parameters were computed breath-by-breath together with the end-expiratory total and compartmental (pulmonary rib cage and abdomen) chest wall volume changes. The correlation properties of these variables were quantified by detrended fluctuation analysis, computing the scaling exponent?. VT, TTOT and the other breathing pattern variables showed ? values between 0.60 (for minute ventilation) to 0.71 (for respiratory rate), all significantly lower than the ones obtained for end-expiratory volumes, that ranged between 1.05 (for rib cage) and 1.13 (for abdomen) with no significant differences between compartments. The much stronger long-range correlations of the end expiratory volumes were interpreted by a neuromechanical network model consisting of five neuron groups in the brain respiratory center coupled with the mechanical properties of the respiratory system modeled as a simple Kelvin body. The model-based ? for VT is 0.57, similar to the experimental data. While the ? for TTOT was slightly lower than the experimental values, the model correctly predicted ? for end-expiratory lung volumes (1.045). In conclusion, we propose that the correlations in the timing and amplitude of the physiological variables originate from the brain with the exception of end-expiratory lung volume, which shows the strongest correlations largely due to the contribution of the viscoelastic properties of the tissues. This cycle-by-cycle variability may have a significant impact on the functioning of adherent cells in the respiratory system. PMID:25803710

Dellaca, Raffaele L.; Aliverti, Andrea; Lo Mauro, Antonella; Lutchen, Kenneth R.; Pedotti, Antonio; Suki, Bela

2015-01-01

113

Gray matter volume correlates of global positive alcohol expectancy in non-dependent adult drinkers.  

PubMed

Alcohol use and misuse is known to involve structural brain changes. Numerous imaging studies have examined changes in gray matter (GM) volumes in dependent drinkers, but there is little information on whether non-dependent drinking is associated with structural changes and whether these changes are related to psychological factors-such as alcohol expectancy-that influence drinking behavior. We used voxel-based morphometry (VBM) to examine whether the global positive scale of alcohol expectancy, as measured by the Alcohol Expectancy Questionnaire-3, is associated with specific structural markers and whether such markers are associated with drinking behavior in 113 adult non-dependent drinkers (66 women). Alcohol expectancy is positively correlated with GM volume of left precentral gyrus (PCG) in men and women combined and bilateral superior frontal gyri (SFG) in women, and negatively correlated with GM volume of the right ventral putamen in men. Furthermore, mediation analyses showed that the GM volume of PCG mediate the correlation of alcohol expectancy and the average number of drinks consumed per occasion and monthly total number of drinks in the past year. When recent drinking was directly accounted for in multiple regressions, GM volume of bilateral dorsolateral prefrontal cortices correlated positively with alcohol expectancy in the combined sample. To our knowledge, these results are the first to identify the structural brain correlates of alcohol expectancy and its mediation of drinking behaviors. These findings suggest that more studies are needed to investigate increased GM volume in the frontal cortices as a neural correlate of alcohol expectancy. PMID:23461484

Ide, Jaime S; Zhang, Sheng; Hu, Sien; Matuskey, David; Bednarski, Sarah R; Erdman, Emily; Farr, Olivia M; Li, Chiang-Shan R

2014-09-01

114

Unitary matrices for phase-coded holographic memories  

Microsoft Academic Search

Volume holographic data storage based on phase-code multiplexing is a promising technology for next generation optical storage devices. Volume holographic memories offer high storage capacities and short data access times through multiplexing and a page-oriented storage principle. Multiple holograms can be recorded in the storage media through various multiplexing techniques, such as angular, phase-code, wavelength or shift multiplexing. Among the

W. Horn; G. Berger; M. Dietz; X. Zhang; C. Denz

2007-01-01

115

Bragg holographic structures for XUV applications: a new approach  

SciTech Connect

We report a new technique for producing high-efficiency XUV Bragg (volume) holographic optical elements by recording interference patterns in a photosensitive coating in either the visible or XUV region. Theoretical calculations and analysis of experimental results have successfully demonstrated the significance of this new fabrication methodology for XUV holographic optical elements, with over 25% diffraction efficiency achieved. In addition, volume holographic optics offer high flexibility in conventional and nonconventional operations, high laser-damage threshold and temperature stability, low surface roughness, and cost effectiveness in mass production.

Jannson, T.; Savant, G.; Qiao, Y.

1989-04-01

116

Correlation between brain volume loss and clinical and MRI outcomes in multiple sclerosis  

PubMed Central

Objective: We investigated the determinants and clinical correlations of MRI-detected brain volume loss (BVL) among patients with relapsing-remitting multiple sclerosis from the phase 3 trials of fingolimod: FREEDOMS, FREEDOMS II, and TRANSFORMS. Methods: Post hoc analyses were conducted in the intent-to-treat populations from each trial and in a combined dataset of 3,635 patients from the trials and their extensions. The relationship between brain volume changes and demographic, clinical, and MRI parameters was studied in pairwise correlations (Pearson) and in multiple regression models. The relative frequency of confirmed disability progression was evaluated in the combined dataset by strata of concurrent BVL at up to 4 years. Results: Increasing age, disease duration, T2 lesion volume, T1-hypointense lesion volume, and disability were associated with reduced brain volume (p < 0.001, all). The strongest individual baseline predictors of on-study BVL were T2 lesion volume, gadolinium-enhancing lesion count, and T1-hypointense lesion volume (p < 0.01, all). During each study, BVL correlated most strongly with cumulative gadolinium-enhancing lesion count, new/enlarged T2 lesion count (p < 0.001, both), and number of confirmed on-study relapses (p < 0.01). Over 4 years in the combined dataset (mean exposure to study drug, 2.4 years), confirmed disability progression was most frequent in patients with greatest BVL. Conclusions: Rate of BVL in patients during the fingolimod trials correlated with disease severity at baseline and new disease activity on study, and was associated with worsening disability. PMID:25632085

Radue, Ernst-Wilhelm; Barkhof, Frederik; Sprenger, Till; Häring, Dieter A.; de Vera, Ana; von Rosenstiel, Philipp; Bright, Jeremy R.; Francis, Gordon; Cohen, Jeffrey A.

2015-01-01

117

RELAP5/MOD3 code manual. Volume 4, Models and correlations  

SciTech Connect

The RELAP5 code has been developed for best-estimate transient simulation of light water reactor coolant systems during postulated accidents. The code models the coupled behavior of the reactor coolant system and the core for loss-of-coolant accidents and operational transients such as anticipated transient without scram, loss of offsite power, loss of feedwater, and loss of flow. A generic modeling approach is used that permits simulating a variety of thermal hydraulic systems. Control system and secondary system components are included to permit modeling of plant controls, turbines, condensers, and secondary feedwater systems. RELAP5/MOD3 code documentation is divided into seven volumes: Volume I presents modeling theory and associated numerical schemes; Volume II details instructions for code application and input data preparation; Volume III presents the results of developmental assessment cases that demonstrate and verify the models used in the code; Volume IV discusses in detail RELAP5 models and correlations; Volume V presents guidelines that have evolved over the past several years through the use of the RELAP5 code; Volume VI discusses the numerical scheme used in RELAP5; and Volume VII presents a collection of independent assessment calculations.

NONE

1995-08-01

118

Correlation between Gray/White Matter Volume and Cognition in Healthy Elderly People  

ERIC Educational Resources Information Center

This study applied volumetric analysis and voxel-based morphometry (VBM) of brain magnetic resonance (MR) images to assess whether correlations exist between global and regional gray/white matter volume and the cognitive functions of semantic memory and short-term memory, which are relatively well preserved with aging, using MR image data from 109…

Taki, Yasuyuki; Kinomura, Shigeo; Sato, Kazunori; Goto, Ryoi; Wu, Kai; Kawashima, Ryuta; Fukuda, Hiroshi

2011-01-01

119

The correlation between brain gray matter volume and empathizing and systemizing quotients in healthy children.  

PubMed

The abilities to empathize and to systemize, two fundamental dimensions of cognitive style, are characterized by apparent individual differences. These abilities are typically measured using an empathizing quotient (EQ) and a systemizing quotient (SQ) questionnaire, respectively. The purpose of this study was to reveal any correlations between EQ and SQ scores and regional gray matter volumes in healthy children by applying voxel-based morphometry to magnetic resonance images. We collected MRIs of brain structure and administered children's versions of the EQ and SQ questionnaires (EQ-C and SQ-C, respectively) to 261 healthy children aged 5-15 years. Structural MRI data were segmented, normalized, and smoothed using an optimized voxel-based morphometric analysis. Next, we analyzed the correlation between regional gray matter volume and EQ-C and SQ-C scores adjusting for age, sex, and intracranial volume. The EQ-C scores showed significant positive correlations with the regional gray matter volumes of the left fronto-opercular and superior temporal cortices, including the precentral gyrus, the inferior frontal gyrus, the superior temporal gyrus, and the insula, which are functionally related to empathic processing. Additionally, SQ-C scores showed a significant negative correlation with the regional gray matter volume of the left posterior parietal cortex, which is functionally involved in selective attention processing. Our findings suggest that individual differences in cognitive style pertaining to empathizing or systemizing abilities could be explained by differences in the volume of brain structures that are functionally relevant to empathizing and systemizing. PMID:22369996

Sassa, Yuko; Taki, Yasuyuki; Takeuchi, Hikaru; Hashizume, Hiroshi; Asano, Michiko; Asano, Kohei; Wakabayashi, Akio; Kawashima, Ryuta

2012-05-01

120

Holographic entropy production  

NASA Astrophysics Data System (ADS)

The suspicion that gravity is holographic has been supported mainly by a variety of specific examples from string theory. In this paper, we propose that such a holography can actually be observed in the context of Einstein's gravity and at least a class of generalized gravitational theories, based on a definite holographic principle where neither is the bulk space-time required to be asymptotically AdS nor the boundary to be located at conformal infinity, echoing Wilson's formulation of quantum field theory. After showing the general equilibrium thermodynamics from the corresponding holographic dictionary, in particular, we provide a rather general proof of the equality between the entropy production on the boundary and the increase of black hole entropy in the bulk, which can be regarded as strong support to this holographic principle. The entropy production in the familiar holographic superconductors/superfluids is investigated as an important example, where the role played by the holographic renormalization is explained.

Tian, Yu; Wu, Xiao-Ning; Zhang, Hongbao

2014-10-01

121

Profilometry with volume holographic imaging  

E-print Network

High resolution, non-contact object profile measurement (profilometry) at long working distance is important in a number of application areas, such as precise parts manufacturing, optical element grounding and polishing, ...

Sun, Wenyang

2006-01-01

122

Holographic Meson Melting  

E-print Network

The plasma phase at high temperatures of a strongly coupled gauge theory can be holographically modelled by an AdS black hole. Matter in the fundamental representation and in the quenched approximation is introduced through embedding D7-branes in the AdS-Schwarzschild background. Low spin mesons correspond to the fluctuations of the D7-brane world volume. As is well known by now, there are two different kinds of embeddings, either reaching down to the black hole horizon or staying outside of it. In the latter case the fluctuations of the D7-brane world volume represent stable low spin mesons. In the plasma phase we do not expect mesons to be stable but to melt at sufficiently high temperature. We model the late stages of this meson melting by the quasinormal modes of D7-brane fluctuations for the embeddings that do reach down to the horizon. The inverse of the imaginary part of the quasinormal frequency gives the typical relaxation time back to equilibrium of the meson perturbation in the hot plasma. We briefly comment on the possible application of our model to quarkonium suppression.

Carlos Hoyos; Karl Landsteiner; Sergio Montero

2007-07-11

123

Holographic Meson Melting  

E-print Network

The plasma phase at high temperatures of a strongly coupled gauge theory can be holographically modelled by an AdS black hole. Matter in the fundamental representation and in the quenched approximation is introduced through embedding D7-branes in the AdS-Schwarzschild background. Low spin mesons correspond to the fluctuations of the D7-brane world volume. As is well known by now, there are two different kinds of embeddings, either reaching down to the black hole horizon or staying outside of it. In the latter case the fluctuations of the D7-brane world volume represent stable low spin mesons. In the plasma phase we do not expect mesons to be stable but to melt at sufficiently high temperature. We model this meson melting by the quasinormal modes of D7-brane fluctuations for the embeddings that do reach down to the horizon. The inverse of the imaginary part of the quasinormal frequency gives the lifetime of the meson in the hot plasma. We briefly comment on the possible application of our model to quarkonium s...

Hoyos, C; Montero, S; Hoyos, Carlos; Landsteiner, Karl; Montero, Sergio

2007-01-01

124

Holographic dark energy reexamined  

SciTech Connect

We have reexamined the holographic dark energy model by considering the spatial curvature. We have refined the model parameter and observed that the holographic dark energy model does not behave as phantom model. Comparing the holographic dark energy model to the supernova observation alone, we found that the closed Universe is favored. Combining with the Wilkinson microwave anisotropy probe (WMAP) data, we obtained the reasonable value of the spatial curvature of our Universe.

Gong Yungui; Wang Bin; Zhang Yuanzhong [College of Electronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Department of Physics, Fudan University, Shanghai 200433 (China); CCAST (World Laboratory), P.O. Box 8730, Beijing 100080, China and Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080 (China)

2005-08-15

125

Dynamical holographic QCD model  

NASA Astrophysics Data System (ADS)

We develop a dynamical holographic QCD model, which resembles the renormalization group from ultraviolet (UV) to infrared (IR). The dynamical holographic model is constructed in the graviton-dilaton-scalar framework with the dilaton background field ? and scalar field X responsible for the gluodynamics and chiral dynamics, respectively. We summarize the results on hadron spectra, QCD phase transition and transport properties including the jet quenching parameter and the shear/bulk viscosity in the framework of the dynamical holographic QCD model.

Li, Danning; Huang, Mei

2014-11-01

126

Multiwavefront digital holographic television.  

PubMed

This paper presents the full technology chain supporting wide angle digital holographic television from holographic capture of real world objects/scenes to holographic display with an extended viewing angle. The data are captured with multiple CCD cameras located around an object. The display system is based on multiple tilted spatial light modulators (SLMs) arranged in a circular configuration. The capture-display system is linked by a holographic data processing module, which allows for significant decoupling of the capture and display systems. The presented experimental results, based on the reconstruction of real world, variable in time scenes, illustrates imaging dynamics, viewing angle and quality. PMID:24663525

Kujawinska, Malgorzata; Kozacki, Tomasz; Falldorf, Claas; Meeser, Thomas; Hennelly, Bryan M; Garbat, Piotr; Zaperty, Weronika; Niemelä, Mikko; Finke, Grzegorz; Kowiel, Marcin; Naughton, Thomas

2014-02-10

127

Quantitative analysis of the corpus callosum in children with cerebral palsy and developmental delay: correlation with cerebral white matter volume  

Microsoft Academic Search

Background: The direct quantitative correlation between thickness of the corpus callosum and volume of cerebral white matter in children with cerebral palsy and developmental delay has not been demonstrated. Objective: This study was conducted to quantitatively correlate the thickness of the corpus callosum with the volume of cerebral white matter in children with cerebral palsy and developmental delay. Material and

Ashok Panigrahy; Patrick D. Barnes; Robert L. Robertson; Lynn A. Sleeper; James W. Sayre

2005-01-01

128

Beam shaping for holographic techniques  

NASA Astrophysics Data System (ADS)

Uniform intensity of laser radiation is very important in holographic and interferometry technologies, therefore transformation of typical Gaussian distribution of a TEM00 laser to flat-top (top hat) is an actual technical task, it is solved by applying beam shaping optics. Holography and interferometry have specific requirements to a uniform laser beam, most important of them are flatness of phase front and extended depth of field. There are different refractive and diffractive beam shaping approaches used in laser industrial and scientific applications, but only few of them are capable to fulfil the optimum conditions for beam quality demanding holography and interferometry. We suggest applying refractive field mapping beam shapers piShaper, which operational principle presumes almost lossless transformation of Gaussian to flat-top beam with flatness of output wavefront, conserving of beam consistency, providing collimated low divergent output beam, high transmittance, extended depth of field, negligible wave aberration, and achromatic design provides capability to work with several lasers with different wavelengths simultaneously. This approach is used in SLM-based technologies of Computer Generated Holography, Dot-Matrix mastering of security holograms, holographic data storage, holographic projection, lithography, interferometric recording of Volume Bragg Gratings. High optical quality of resulting flat-top beam allows applying additional optical components to vary beam size and shape, thus adapting an optical system to requirements of a particular application. This paper will describe design basics of refractive beam shapers and optical layouts of their applying in holographic systems. Examples of real implementations and experimental results will be presented as well.

Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei

2014-09-01

129

Improving the clinical correlation of multiple sclerosis black hole volume change by paired-scan analysis.  

PubMed

The change in T 1-hypointense lesion ("black hole") volume is an important marker of pathological progression in multiple sclerosis (MS). Black hole boundaries often have low contrast and are difficult to determine accurately and most (semi-)automated segmentation methods first compute the T 2-hyperintense lesions, which are a superset of the black holes and are typically more distinct, to form a search space for the T 1w lesions. Two main potential sources of measurement noise in longitudinal black hole volume computation are partial volume and variability in the T 2w lesion segmentation. A paired analysis approach is proposed herein that uses registration to equalize partial volume and lesion mask processing to combine T 2w lesion segmentations across time. The scans of 247 MS patients are used to compare a selected black hole computation method with an enhanced version incorporating paired analysis, using rank correlation to a clinical variable (MS functional composite) as the primary outcome measure. The comparison is done at nine different levels of intensity as a previous study suggests that darker black holes may yield stronger correlations. The results demonstrate that paired analysis can strongly improve longitudinal correlation (from -0.148 to -0.303 in this sample) and may produce segmentations that are more sensitive to clinically relevant changes. PMID:24179734

Tam, Roger C; Traboulsee, Anthony; Riddehough, Andrew; Li, David K B

2012-01-01

130

Prostate Volumes Derived From MRI and Volume-Adjusted Serum Prostate-Specific Antigen: Correlation With Gleason Score of Prostate Cancer  

PubMed Central

OBJECTIVE The purpose of this article is to study relationships between MRI-based prostate volume and volume-adjusted serum prostate-specific antigen (PSA) concentration estimates and prostate cancer Gleason score. MATERIALS AND METHODS The study included 61 patients with prostate cancer (average age, 63.3 years; range 52–75 years) who underwent MRI before prostatectomy. A semiautomated and MRI-based technique was used to estimate total and central gland prostate volumes, central gland volume fraction (central gland volume divided by total prostate volume), PSA density (PSAD; PSA divided by total prostate volume), and PSAD for the central gland (PSA divided by central gland volume). These MRI-based volume and volume-adjusted PSA estimates were compared with prostatectomy specimen weight and Gleason score by using Pearson (r) or Spearman (?) correlation coefficients. RESULTS The estimated total prostate volume showed a high correlation with reference standard volume (r = 0.94). Of the 61 patients, eight (13.1%) had a Gleason score of 6, 40 (65.6%) had a Gleason score of 7, seven (11.5%) had a Gleason score of 8, and six (9.8%) had a Gleason score of 9 for prostate cancer. The Gleason score was significantly correlated with central gland volume fraction (? = ?0.42; p = 0.0007), PSAD (? = 0.46; p = 0.0002), and PSAD for the central gland (? = 0.55; p = 0.00001). CONCLUSION Central gland volume fraction, PSAD, and PSAD for the central gland estimated from MRI examinations show a modest but significant correlation with Gleason score and have the potential to contribute to personalized risk assessment for significant prostate cancer. PMID:24147475

Karademir, Ibrahim; Shen, Dinggang; Peng, Yahui; Liao, Shu; Jiang, Yulei; Yousuf, Ambereen; Karczmar, Gregory; Sammet, Steffen; Wang, Shiyang; Medved, Milica; Antic, Tatjana; Eggener, Scott; Oto, Aytekin

2015-01-01

131

Finite Volume Corrections and Decay of Correlations in the Canonical Ensemble  

NASA Astrophysics Data System (ADS)

We consider a classical system of N particles confined in a box ? subset R^d interacting via a finite range pair potential. Given the validity of the cluster expansion in the canonical ensemble we compute the error between the finite and the infinite volume free energy and estimate it to be bounded by the area of the surface of the box's boundary over its volume. We also compute the truncated two-point correlation function and find that the contribution from the ideal gas case is of the order 1/|? | plus an exponentially small error with the distance.

Pulvirenti, Elena; Tsagkarogiannis, Dimitrios

2015-02-01

132

Holographic data storage systems  

Microsoft Academic Search

In this paper, we discuss fundamental issues underlying holographic data storage: grating formation, recording and readout of thick and thin holograms, multiplexing techniques, signal-to-noise ratio considerations, and readout techniques suitable for conventional, phase conjugate, and associative search data retrieval. Next, we consider holographic materials characteristics for digital data storage, followed by a discussion on photorefractive media, fixing techniques, and noise

LAMBERTUS HESSELINK; SERGEI S. ORLOV; MATTHEW C. BASHAW

2004-01-01

133

Hydrodynamics of holographic superconductors  

Microsoft Academic Search

We study the poles of the retarded Green functions of a holographic superconductor. The model shows a second order phase transition where a charged scalar operator condenses and a U(1) symmetry is spontaneously broken. The poles of the holographic Green functions are the quasinormal modes in an AdS black hole background. We study the spectrum of quasinormal frequencies in the

Irene Amado; Matthias Kaminski; Karl Landsteiner

2009-01-01

134

Cerebellar vermal volumes and behavioral correlates in children with autism spectrum disorder  

PubMed Central

Cerebellar histopathological abnormalities have been well documented in autism although findings of structural differences, as determined by magnetic resonance imaging, have been less consistent. This report explores specific cerebellar vermal structures and their relation with symptoms severity and cognitive functioning in young children with autism spectrum disorder (ASD). Children with ASD aged 3 to 4 years were compared with chronological age matched typically developing children (TD) and chronologic and mental age matched children with developmental delay (DD). Volumes of the cerebellum and midsagittal vermal areas were measured from 3-D T1-weighted MR images. Children with ASD had reduced total vermis volumes compared to children with TD after controlling for age, sex, and overall cerebral volume or cerebellum volume. In particular, the vermis lobe VI-VII area was reduced in children with ASD compared to TD children. Children with DD had smaller total vermis areas compared to children with ASD and TD. Within the ASD group, cerebellar measurements were not correlated with symptom severity, or verbal, non-verbal or full scale IQ. Within the DD group, larger cerebellar measurements were correlated with less impairments. The specific relation between altered cerebellar structure and symptom expression in autism remains unclear. PMID:19243924

Webb, Sara Jane; Sparks, Bobbi-Faun; Friedman, Seth D.; Shaw, Dennis W. W.; Giedd, Jay; Dawson, Geraldine; Dager, Steven R.

2009-01-01

135

Full Color Holographic Endoscopy  

NASA Astrophysics Data System (ADS)

The ability to produce color holograms from the human tissue represents a major medical advance, specifically in the areas of diagnosis and teaching. This has been achieved at Glyndwr University. In corporation with partners at Gooch & Housego, Moor Instruments, Vivid Components and peninsula medical school, Exeter, UK, for the first time, we have produced full color holograms of human cell samples in which the cell boundary and the nuclei inside the cells could be clearly focused at different depths - something impossible with a two-dimensional photographic image. This was the main objective set by the peninsula medical school at Exeter, UK. Achieving this objective means that clinically useful images essentially indistinguishable from the object human cells could be routinely recorded. This could potentially be done at the tip of a holo-endoscopic probe inside the body. Optimised recording exposure and development processes for the holograms were defined for bulk exposures. This included the optimisation of in-house recording emulsions for coating evaluation onto polymer substrates (rather than glass plates), a key step for large volume commercial exploitation. At Glyndwr University, we also developed a new version of our in-house holographic (world-leading resolution) emulsion.

Osanlou, A.; Bjelkhagen, H.; Mirlis, E.; Crosby, P.; Shore, A.; Henderson, P.; Napier, P.

2013-02-01

136

Digital holographic microscopy for the evaluation of human sperm structure.  

PubMed

The morphology of the sperm head has often been correlated with the outcome of in vitro fertilization, and has been shown to be the sole parameter in semen of value in predicting the success of intracytoplasmic sperm injection and intracytoplasmic morphologically selected sperm injection. In this paper, we have studied whether digital holographic microscopy (DHM) may be useful to obtain quantitative data on human sperm head structure and compared this technique with high-power digitally enhanced Nomarski optics. The main advantage of digital holography is that high-resolution three-dimensional quantitative sample imaging may be automatically produced by numerical refocusing of a two-dimensional image at different object planes without any mechanical scanning. We show that DHM generates useful information on the dimensions and structure of human sperm, not revealed by conventional phase-contrast microscopy, in particular the volume of vacuoles, and suggest its use as an additional prognostic tool in assisted reproduction technology. PMID:23469807

Coppola, G; Di Caprio, G; Wilding, M; Ferraro, P; Esposito, G; Di Matteo, L; Dale, R; Coppola, G; Dale, B

2014-11-01

137

Digital holographic microscopy for the evaluation of human sperm structure  

E-print Network

The morphology of the sperm head has often been correlated with the outcome of in vitro fertilization (IVF), and has been shown to be the sole parameter in semen of value in predicting the success of intracytoplasmic sperm injection (ICSI) and intracytoplasmic morphologically selected sperm injection (IMSI). In this paper, we have studied whether Digital Holographic (DH) microscopy may be useful to obtain quantitative data on human sperm head structure and compared this technique to high power digitally enhanced Nomarski microscope. The main advantage of DH is that a high resolution 3-D quantitative sample imaging may be obtained thorugh numerical refocusing at different object planes without any mechanical scanning. We show that DH can furnish useful information on the dimensions and structure of human spermatozoo, that cannot be revealed by conventional phase contrast microscopy. In fact, in this paper DH has been used to evaluate volume and indicate precise location of vacuoles, thus suggesting its use as ...

Coppola, Gianluca; Wilding, Martin; Ferraro, Pietro; Esposito, Giusy; Di Matteo, Loredana; Dale, Roberta; Coppola, Giuseppe; Dale, Brian

2013-01-01

138

PBMC telomerase activity, but not leukocyte telomere length, correlates with hippocampal volume in major depression.  

PubMed

Accelerated cell aging, indexed in peripheral leukocytes by telomere shortness and in peripheral blood mononuclear cells (PBMCs) by telomerase activity, has been reported in several studies of major depressive disorder (MDD). However, the relevance of these peripheral measures for brain indices that are presumably more directly related to MDD pathophysiology is unknown. In this study, we explored the relationship between PBMC telomerase activity and leukocyte telomere length and magnetic resonance imaging-estimated hippocampal volume in un-medicated depressed individuals and healthy controls. We predicted that, to the extent peripheral and central telomerase activity are directly related, PBMC telomerase activity would be positively correlated with hippocampal volume, perhaps due to hippocampal telomerase-associated neurogenesis, neuroprotection or neurotrophic facilitation, and that this effect would be clearer in individuals with increased PBMC telomerase activity, as previously reported in un-medicated MDD. We did not have specific hypotheses regarding the relationship between leukocyte telomere length and hippocampal volume, due to conflicting reports in the published literature. We found, in 25 un-medicated MDD subjects, that PBMC telomerase activity was significantly positively correlated with hippocampal volume; this relationship was not observed in 18 healthy controls. Leukocyte telomere length was not significantly related to hippocampal volume in either group (19 unmedicated MDD subjects and 17 healthy controls). Although the nature of the relationship between peripheral telomerase activity and telomere length and the hippocampus is unclear, these preliminary data are consistent with the possibility that PBMC telomerase activity indexes, and may provide a novel window into, hippocampal neuroprotection and/or neurogenesis in MDD. PMID:25773002

Wolkowitz, Owen M; Mellon, Synthia H; Lindqvist, Daniel; Epel, Elissa S; Blackburn, Elizabeth H; Lin, Jue; Reus, Victor I; Burke, Heather; Rosser, Rebecca; Mahan, Laura; Mackin, Scott; Yang, Tony; Weiner, Michael; Mueller, Susanne

2015-04-30

139

All-optical system based on holographic interconnections  

Microsoft Academic Search

Applications of holographic interconnections to all-optical systems are discussed. We demonstrated a full-optical fiber sensing system and an all-optical translation system based on random phase encoding in volume holograms. In, addition, an angle detection system using angular multiplexing in volume holograms is also proposed.

Ching-Cherng Sun; Wei-Chia Su; Chih-Yuan Hsu; Yi-Min Chen; Yuh Ouyang

2001-01-01

140

Characteristic free volumes of bulk metallic glasses: Measurement and their correlation with glass-forming ability  

SciTech Connect

A convenient method is proposed for the measurement of the characteristic free volumes, viz., the amount of excess free volume annihilation in structural relaxation V{sub f-sr} and the amount of new free volume production in glass transition V{sub f-gt} of bulk metallic glasses (BMGs) by thermal dilation (DIL) test. Through the DIL tests, the characteristic free volumes are found to be sensitive to the change of glass forming ability (GFA). The Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} BMG has a quite small V{sub f-sr}. For a series of Fe-Cr-Mo-C-B-(Er) BMGs, Fe{sub 48}Cr{sub 15}Mo{sub 14}C{sub 15}B{sub 6}Er{sub 2} with the largest GFA is identified to have the largest V{sub f-gt} and smallest V{sub f-sr}. The correlation between V{sub f-sr} and the squares of critical diameters of these iron-based BMGs can be fitted as a negative exponential function with high accuracy.

Hu Qiang [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072 (China); Zeng Xierong [College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060 (China) and Shenzhen Key Laboratory of Special Functional Materials, Shenzhen 518060 (China); Fu, M. W. [Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

2011-03-01

141

Correlation of neurocognitive function and brain parenchyma volumes in children surviving cancer  

NASA Astrophysics Data System (ADS)

This research builds on our hypothesis that white matter damage and associated neurocognitive symptoms, in children treated for cancer with cranial spinal irradiation, spans a continuum of severity that can be reliably probed using non-invasive MR technology. Quantitative volumetric assessments of MR imaging and psychological assessments were obtained in 40 long-term survivors of malignant brain tumors treated with cranial irradiation. Neurocognitive assessments included a test of intellect (Wechsler Intelligence Test for Children, Wechsler Adult Intelligence Scale), attention (Conner's Continuous Performance Test), and memory (California Verbal Learning Test). One-sample t-tests were conducted to evaluate test performance of survivors against age-adjusted scores from the test norms; these analyses revealed significant impairments in all apriori selected measures of intelligence, attention, and memory. Partial correlation analyses were performed to assess the relationships between brain tissues volumes (normal appearing white matter (NAWM), gray matter, and CSF) and neurocognitive function. Global intelligence (r = 0.32, p = 0.05) and global attentional (r = 0.49, p < 0.01) were significantly positively correlated with NAWM volumes, whereas global memory was significantly positively correlated with overall brain parenchyma (r = 0.38, p = 0.04). We conclude that quantitative assessment of MR examinations in survivors of childhood cancer treated with cranial irradiation reveal that loss of NAWM is associated with decreased intellectual and attentional deficits, whereas overall parenchyma loss, as reflected by increased CSF and decreased white matter, is associated with memory-related deficits.

Reddick, Wilburn E.; White, Holly A.; Glass, John O.; Mulhern, Raymond K.

2002-04-01

142

Finite volume corrections and decay of correlations in the canonical ensemble  

E-print Network

We consider a classical system of $N$ particles confined in a box $\\Lambda\\subset\\mathbb{R}^d$ interacting via a finite range pair potential. Given the validity of the cluster expansion in the canonical ensemble we compute the error between the finite and the infinite volume free energy and estimate it to be bounded by the area of the surface of the box's boundary over its volume. We also compute the truncated two-point correlation function and find that the contribution from the ideal gas case is of the order $1/N$ while the contribution of the interactions is of the order $1/|\\Lambda|$ plus an exponentially small error with the distance.

Elena Pulvirenti; Dimitrios Tsagkarogiannis

2015-02-16

143

Holographic particle image velocimetry measurements in a four-valve combustion engine  

NASA Astrophysics Data System (ADS)

This is a feasibility study to show that the nonreacting three-dimensional flow in the cylinder of a four-valve internal combustion engine at 160° after top dead center (atdc) at 1,500 rpm can be accurately measured by holographic particle image velocimetry. The results evidence the quality of holographic PIV measurements in engine flows and the capability of the holographic method to instantaneously capture the complete three-dimensional flow field in a large area of the highly intricate cylinder flow. The resolved measurement volume has a diameter of about 60 mm and a height of 80 mm with a vector spacing of 0.75 mm per vector. To validate the measurements, the flow structure as well as the turbulent kinetic energy of the flow field is compared with planar two-component/two-dimensional (2C/2D-PIV) measurements performed in the same engine (Dannemann et al., in Exp Fluids 2010). Furthermore, the spatial propagation of the flow field as well as the vortical structures is visualized by 3D streamlines and ? 2-contours. The current results confirm the existence of several large-scale flow structures, such as a counter-rotating ring-vortex pair below the inlet valve and the tumble vortex. The latter possesses a U-shaped propagation of the vortex core. The analysis of the two-point correlation shows the integral length scale to be in the range 2.5-6.1 mm, which is in agreement with literature data.

van Overbrüggen, Timo; Dannemann, Jan; Klaas, Michael; Schröder, Wolfgang

2014-01-01

144

Intracranial pressure pulse waveform correlates with aqueductal cerebrospinal fluid stroke volume  

PubMed Central

This study identifies a novel relationship between cerebrospinal fluid (CSF) stroke volume through the cerebral aqueduct and the characteristic peaks of the intracranial pulse (ICP) waveform. ICP waveform analysis has become much more advanced in recent years; however, clinical practice remains restricted to mean ICP, mainly due to the lack of physiological understanding of the ICP waveform. Therefore, the present study set out to shed some light on the physiological meaning of ICP morphological metrics derived by the morphological clustering and analysis of continuous intracranial pulse (MOCAIP) algorithm by investigating their relationships with a well defined physiological variable, i.e., the stroke volume of CSF through the cerebral aqueduct. Seven patients received both overnight ICP monitoring along with a phase-contrast MRI (PC-MRI) of the cerebral aqueduct to quantify aqueductal stroke volume (ASV). Waveform morphological analysis of the ICP signal was performed by the MOCAIP algorithm. Following extraction of morphological metrics from the ICP signal, nine temporal ICP metrics and two amplitude-based metrics were compared with the ASV via Spearman's rank correlation. Of the nine temporal metrics correlated with the ASV, only the width of the P2 region (ICP-Wi2) reached significance. Furthermore, both ICP pulse pressure amplitude and mean ICP did not reach significance. In this study, we showed the width of the second peak (ICP-Wi2) of an ICP pulse wave is positively related to the volume of CSF movement through the cerebral aqueduct. This finding is an initial step in bridging the gap between ICP waveform morphology research and clinical practice. PMID:22995390

Hamilton, Robert; Baldwin, Kevin; Fuller, Jennifer; Vespa, Paul; Hu, Xiao

2012-01-01

145

Intracranial pressure pulse waveform correlates with aqueductal cerebrospinal fluid stroke volume.  

PubMed

This study identifies a novel relationship between cerebrospinal fluid (CSF) stroke volume through the cerebral aqueduct and the characteristic peaks of the intracranial pulse (ICP) waveform. ICP waveform analysis has become much more advanced in recent years; however, clinical practice remains restricted to mean ICP, mainly due to the lack of physiological understanding of the ICP waveform. Therefore, the present study set out to shed some light on the physiological meaning of ICP morphological metrics derived by the morphological clustering and analysis of continuous intracranial pulse (MOCAIP) algorithm by investigating their relationships with a well defined physiological variable, i.e., the stroke volume of CSF through the cerebral aqueduct. Seven patients received both overnight ICP monitoring along with a phase-contrast MRI (PC-MRI) of the cerebral aqueduct to quantify aqueductal stroke volume (ASV). Waveform morphological analysis of the ICP signal was performed by the MOCAIP algorithm. Following extraction of morphological metrics from the ICP signal, nine temporal ICP metrics and two amplitude-based metrics were compared with the ASV via Spearman's rank correlation. Of the nine temporal metrics correlated with the ASV, only the width of the P2 region (ICP-Wi2) reached significance. Furthermore, both ICP pulse pressure amplitude and mean ICP did not reach significance. In this study, we showed the width of the second peak (ICP-Wi2) of an ICP pulse wave is positively related to the volume of CSF movement through the cerebral aqueduct. This finding is an initial step in bridging the gap between ICP waveform morphology research and clinical practice. PMID:22995390

Hamilton, Robert; Baldwin, Kevin; Fuller, Jennifer; Vespa, Paul; Hu, Xiao; Bergsneider, Marvin

2012-11-01

146

Making of a holographic movie on film: from holographic animation to holographic movie  

NASA Astrophysics Data System (ADS)

Throughout `EI' '92, '93, '94 and '95, we have been presenting an experimental holographic movie system as a tool to estimate the picture quality of moving holographic images as a step towards holographic TV. Therefore these presentations can be seen as experiments for holographic movie system. They present holographic move devices as well as instruction on how to make holographic movies on film. Holographic movies are possible as we will report in this presentation. Throughout holographic movie devices I, II, III and IV, the same equipment and technology has been used. This will be recognized and appreciated by holographic researchers. Nowadays to record holographic images, it is best to use holographic film (in the case of animation, there is no other method). Through this method in each new version, we have been trying to broaden our expressions and artist's image in using new technology and take a further step for better holographic movies on film. In the future holographic movies will become popular. But now in their research phase we are working on animated movies as not only an presentation of technique but also as an artist's expression as well. We are making these technology with the general concept and intention of appealing to the senses of all people. These are not only holographic animation pieces but also 3D sounds and a construction of images in time. We have approached this concept with a most positive attitude.

Hiyama, Shigeo; Higuchi, Kazuhito; Ishii, Ken'ichiro; Ishikawa, Jun; Ohara, Tomoko; Muraho, Shuji

1995-04-01

147

Simple holographic insulator  

NASA Astrophysics Data System (ADS)

We present a simple holographic model of an insulator. Unlike most previous holographic insulators, the zero temperature infrared geometry is completely nonsingular. Both the low temperature DC conductivity and the optical conductivity at zero temperature satisfy power laws with the same exponent, given by the scaling dimension of an operator in the IR. Changing a parameter in the model converts it from an insulator to a conductor with a standard Drude peak.

Mefford, Eric; Horowitz, Gary T.

2014-10-01

148

A Simple Holographic Insulator  

E-print Network

We present a simple holographic model of an insulator. Unlike most previous holographic insulators, the zero temperature infrared geometry is completely nonsingular. Both the low temperature DC conductivity and the optical conductivity at zero temperature satisfy power laws with the same exponent, given by the scaling dimension of an operator in the IR. Changing a parameter in the model converts it from an insulator to a conductor with a standard Drude peak.

Eric Mefford; Gary T. Horowitz

2014-07-11

149

Lippmann-Bragg broadband holographic mirrors  

SciTech Connect

Lippmann-Bragg broadband volume holographic mirrors, with chirp normal to the surface, represent an entirely new class of grating. These gratings are presented and analyzed theoretically by using a combination of the multiple-beam interference method and Kogelnik's local solution for uniform gratings. Particularly noteworthy is the new grating's combination of a very high Bragg diffraction efficiency (> 99.5%) with a large tunable bandwidth (from 5 to > 300 nm).

Jannson, T.; Tengara, I.; Qiao, Y.; Savant, G. (Physical Optics Corp., Torrance, CA (United States))

1991-01-01

150

Holographic rugate structures for x-ray optics applications  

SciTech Connect

XUV Bragg Holographic Optical Elements (HOEs), based on a single-step volume holographic recording, have been proposed by Physical Optic Corporation (POC), as an entirely new approach to x-ray optics. Their theory, as well as the first experimental proof-of-concept, have been demonstrated in Phase 1 of the DOE program. During the first year (exactly, 8-month duration) of the on-going Phase 2, the high-efficiency XUV Lippmann holographic mirrors have been fabricated and their optical, physical, and material properties have been investigated over the entire XUV region (1--100nm). The XUV Bragg HOEs, based on dichromated gelatin (DCG) and on DCG/polymer grafts, have been recorded in the visible region (using an Innova Argo laser) and reconstructed using twelve XUV wavelengths. In addition, these phase high-resolution holographic materials have been shown to be suitable to direct x-ray laser holographic recording (using Princeton's x-ray laser). The volume x-ray holographic recording will be realized within the second year of the program effort.

Jannson, T.; Savant, Gajendra.; Qiao, Yong.

1988-07-01

151

Reconstruction of the 3D representative volume element from the generalized two-point correlation function  

NASA Astrophysics Data System (ADS)

This paper presents the first application of three-dimensional (3D) cross-correlation microstructure reconstruction implemented for a representative volume element (RVE) to facilitate the microstructure engineering of materials. This has been accomplished by developing a new methodology for reconstructing 3D microstructure using experimental two-dimensional electron backscatter diffraction data. The proposed methodology is based on the analytical representation of the generalized form of the two-point correlation function—the distance-disorientation function (DDF). Microstructure reconstruction is accomplished by extending the simulated annealing techniques to perform three term reconstruction with a minimization of the DDF. The new 3D microstructure reconstruction algorithm is employed to determine the 3D RVE containing all of the relevant microstructure information for accurately computing the mechanical response of solids, especially when local microstructural variations influence the global response of the material as in the case of fracture initiation.

Staraselski, Y.; Brahme, A.; Mishra, R. K.; Inal, K.

2015-01-01

152

Power-law correlations in finance-related Google searches, and their cross-correlations with volatility and traded volume: Evidence from the Dow Jones Industrial components  

E-print Network

We study power-law correlations properties of the Google search queries for Dow Jones Industrial Average (DJIA) component stocks. Examining the daily data of the searched terms with a combination of the rescaled range and rescaled variance tests together with the detrended fluctuation analysis, we show that the searches are in fact power-law correlated with Hurst exponents between 0.8 and 1.1. The general interest in the DJIA stocks is thus strongly persistent. We further reinvestigate the cross-correlation structure between the searches, traded volume and volatility of the component stocks using the detrended cross-correlation and detrending moving-average cross-correlation coefficients. Contrary to the universal power-law correlations structure of the related Google searches, the results suggest that there is no universal relationship between the online search queries and the analyzed financial measures. Even though we confirm positive correlation for a majority of pairs, there are several pairs with insign...

Kristoufek, Ladislav

2015-01-01

153

High-Transfer-Rate High-Capacity Holographic Disk Data-Storage System  

Microsoft Academic Search

We describe the design and implementation of a high-data-rate high-capacity digital holographic storage disk system. Various system design trade-offs that affect density and data-rate performance are described and analyzed. In the demonstration system that we describe, high-density holographic recording is achieved by use of high-resolution short-focal-length optics and correlation shift multiplexing in photopolymer disk media. Holographic channel decoding at a

Sergei S. Orlov; William Phillips; Eric Bjornson; Yuzuru Takashima; Padma Sundaram; Lambertus Hesselink; Robert Okas; Darren Kwan; Raymond Snyder

2004-01-01

154

The techniques of holographic particle sizing  

NASA Technical Reports Server (NTRS)

Depending on the mechanism of particle production, the resultant particle size and velocity distribution may range over several orders of magnitude. In general, if particle size information is desired from a given type generator, one must resort to some form of experimental determination of the distribution. If the source of particle production is a dynamic one involving a reasonable volume, holography provides a tailor-made particle size and velocity distribution detector. This is evidenced by the fact that holography allows the entire volume to be recorded on one exposure without any interference with the volume of interest. Herein lies a very important characteristic of the holographic particle detection technique: It provides a holographic nondestructive testing technique in the fullest sense of the definition of nondestructive testing. This report provides a description of three different systems useful in this technique and includes the experimental results from one of the holographic systems which was used to detect particle size and velocity distribution from the Skylab waste tank.

Kurtz, R. L.

1973-01-01

155

Friedmann Propulsion in an Flat Holographic Universe  

NASA Astrophysics Data System (ADS)

Because of inversion symmetries in holographic systems, the spatial compression of lower-dimensional holographic memory leads to an expansion of the holographic image and vice versa (scaling duality), where the geometric mean between the small quantum memory and cosmic image scale defines the inversion scale, the unit scale to normalize the global holographic currents of momentum exchange. Assigning to the cosmic image (bulk) a 4d, to the quantum memory (baryon) a 2d, and to the inversion scale a 3d spherical topology, the cosmic critical density in the flat FRW cosmic test model corresponds to 1 memory unit (baryon). Otherwise, if we expect expansion driven by 3d Einstein gravity on all scales, we get the well known cosmic ``dark matter'' deficit of 96% or 0.04 baryons per unit volume. The cosmic deficit or quantum excess is assigned by Gauss law to the topological ratio 4d bulk surface S3 to 2d quantum surface S1, which dilutes gravity or the mass density by the dimensionless factor 0.04~S3/2/S13 = 1/(8?) leading to a theoretical Hubble parameter of 73.2 kms-1 Mpc-1. Regarding propulsion based on fractional linear transforms mapping the quantum compression by inversion to a cosmic expansion, the anisotropic transform resembles the Alcubierre mechanism if expansion is behind and the compression ahead of the spaceship.

Binder, Bernd

2008-01-01

156

Serotonergic, brain volume and attentional correlates of trait anxiety in primates.  

PubMed

Trait anxiety is a risk factor for the development and maintenance of affective disorders, and insights into the underlying brain mechanisms are vital for improving treatment and prevention strategies. Translational studies in non-human primates, where targeted neurochemical and genetic manipulations can be made, are critical in view of their close neuroanatomical similarity to humans in brain regions implicated in trait anxiety. Thus, we characterised the serotonergic and regional brain volume correlates of trait-like anxiety in the marmoset monkey. Low- and high-anxious animals were identified by behavioral responses to a human intruder (HI) that are known to be sensitive to anxiolytic drug treatment. Extracellular serotonin levels within the amygdala were measured with in vivo microdialysis, at baseline and in response to challenge with the selective serotonin reuptake inhibitor, citalopram. Regional brain volume was assessed by structural magnetic resonance imaging. Anxious individuals showed persistent, long-term fearful responses to both a HI and a model snake, alongside sustained attention (vigilance) to novel cues in a context associated with unpredictable threat. Neurally, high-anxious marmosets showed reduced amygdala serotonin levels, and smaller volumes in a closely connected prefrontal region, the dorsal anterior cingulate cortex. These findings highlight behavioral and neural similarities between trait-like anxiety in marmosets and humans, and set the stage for further investigation of the processes contributing to vulnerability and resilience to affective disorders. PMID:25586542

Mikheenko, Yevheniia; Shiba, Yoshiro; Sawiak, Stephen; Braesicke, Katrin; Cockcroft, Gemma; Clarke, Hannah; Roberts, Angela C

2015-05-01

157

Canonical correlation analysis of video volume tensors for action categorization and detection.  

PubMed

This paper addresses a spatiotemporal pattern recognition problem. The main purpose of this study is to find a right representation and matching of action video volumes for categorization. A novel method is proposed to measure video-to-video volume similarity by extending Canonical Correlation Analysis (CCA), a principled tool to inspect linear relations between two sets of vectors, to that of two multiway data arrays (or tensors). The proposed method analyzes video volumes as inputs avoiding the difficult problem of explicit motion estimation required in traditional methods and provides a way of spatiotemporal pattern matching that is robust to intraclass variations of actions. The proposed matching is demonstrated for action classification by a simple Nearest Neighbor classifier. We, moreover, propose an automatic action detection method, which performs 3D window search over an input video with action exemplars. The search is speeded up by dynamic learning of subspaces in the proposed CCA. Experiments on a public action data set (KTH) and a self-recorded hand gesture data showed that the proposed method is significantly better than various state-of-the-art methods with respect to accuracy. Our method has low time complexity and does not require any major tuning parameters. PMID:19542576

Kim, Tae-Kyun; Cipolla, Roberto

2009-08-01

158

GSTM1 Gene Expression Correlates to Leiomyoma Volume Regression in Response to Mifepristone Treatment  

PubMed Central

Progesterone receptor modulators, such as mifepristone are useful and well tolerated in reducing leiomyoma volume although with large individual variation. The objective of this study was to investigate the molecular basis for the observed leiomyoma volume reduction, in response to mifepristone treatment and explore a possible molecular marker for the selective usage of mifepristone in leiomyoma patients. Premenopausal women (N?=?14) were treated with mifepristone 50 mg, every other day for 12 weeks prior to surgery. Women were arbitrarily sub-grouped as good (N?=?4), poor (N?=?4) responders to treatment or intermediate respondents (N?=?3). Total RNA was extracted from leiomyoma tissue, after surgical removal of the tumour and the differential expression of genes were analysed by microarray. The results were analysed using Ingenuity Pathway Analysis software. The glutathione pathway was the most significantly altered canonical pathway in which the glutathione-s transferase mu 1 (GSTM1) gene was significantly over expressed (+8.03 folds) among the good responders compared to non responders. This was further confirmed by Real time PCR (p?=?0.024). Correlation of immunoreactive scores (IRS) for GSTM1 accumulation in leiomyoma tissue was seen with base line volume change of leiomyoma R?=??0.8 (p?=?0.011). Furthermore the accumulation of protein GSTM1 analysed by Western Blot correlated significantly with the percentual leiomyoma volume change R?=??0.82 (p?=?0.004). Deletion of the GSTM1 gene in leiomyoma biopsies was found in 50% of the mifepristone treated cases, with lower presence of the GSTM1 protein. The findings support a significant role for GSTM1 in leiomyoma volume reduction induced by mifepristone and explain the observed individual variation in this response. Furthermore the finding could be useful to further explore GSTM1 as a biomarker for tailoring medical treatment of uterine leiomyomas for optimizing the response to treatment. Clinical Trials identifier www.clinicaltrials.gov: NCT00579475, Protocol date: November 2004. http://clinicaltrials.gov/ct2/show/NCT00579475 PMID:24324590

Engman, Mikael; Varghese, Suby; Lagerstedt Robinson, Kristina; Malmgren, Helena; Hammarsjö, Anna; Byström, Birgitta; L Lalitkumar, Parameswaran Grace; Gemzell-Danielsson, Kristina

2013-01-01

159

Correlation between gall bladder fasting volume and postprandial emptying in patients with gall stones and healthy controls.  

PubMed Central

To evaluate whether the extent of postprandial gall bladder emptying is correlated with gall bladder fasting volume, gall bladder motility was studied in 56 patients with cholesterol gall stone and 19 control patients. Gall bladder volumes were determined sonographically, while cholecystokinin plasma values were measured radioimmunologically. Twenty three per cent of gall stone patients were classified as pathological contractors (residual fraction > mean +2SD of controls) and 77% as normal contractors. Normal but not pathological contractor patients exhibited larger gall bladder fasting volumes (mean (SEM)) (24.7 (1.7) ml) than controls (15.3 (1.2) ml, p < 0.001). In normal contractor patients and controls fasting volume was closely related with ejection volume (r = 0.97, p < 0.001) and residual volume (r = 0.80, p < 0.001). Although ejection volume was enlarged in normal contractor patients it did not compensate the increase in fasting volume. Thus, residual volumes were considerably increased not only in pathological contractors (12.7 (2.5) ml, p < 0.001) but also in normal contractor patients (7.0 (0.5) v 4.6 (0.6) ml, p < 0.001). Postprandial cholecystokinin secretion did not differ between patients and controls. It is concluded, that in normal contractor patients gall bladder fasting volume is closely correlated with ejection and residual volume. Thus, fasting volume may be an essential factor affecting postprandial gall bladder emptying. Large fasting volumes in cholesterol gall stone disease could thereby contribute to bile retention, which facilitates gall stone growth. PMID:8244118

Pauletzki, J; Cicala, M; Holl, J; Sauerbruch, T; Schafmayer, A; Paumgartner, G

1993-01-01

160

Holographic non-Fermi-liquid fixed points.  

PubMed

Techniques arising from string theory can be used to study assemblies of strongly interacting fermions. Via this 'holographic duality', various strongly coupled many-body systems are solved using an auxiliary theory of gravity. Simple holographic realizations of finite density exhibit single-particle spectral functions with sharp Fermi surfaces, of a form distinct from those of the Landau theory. The self-energy is given by a correlation function in an infrared (IR) fixed-point theory that is represented by a two-dimensional anti de Sitter space (AdS(2)) region in the dual gravitational description. Here, we describe in detail the gravity calculation of this IR correlation function. PMID:21422019

Faulkner, Tom; Iqbal, Nabil; Liu, Hong; McGreevy, John; Vegh, David

2011-04-28

161

Dynamic volume vs respiratory correlated 4DCT for motion assessment in radiation therapy simulation  

SciTech Connect

Purpose: Conventional (i.e., respiratory-correlated) 4DCT exploits the repetitive nature of breathing to provide an estimate of motion; however, it has limitations due to binning artifacts and irregular breathing in actual patient breathing patterns. The aim of this work was to evaluate the accuracy and image quality of a dynamic volume, CT approach (4D{sub vol}) using a 320-slice CT scanner to minimize these limitations, wherein entire image volumes are acquired dynamically without couch movement. This will be compared to the conventional respiratory-correlated 4DCT approach (RCCT). Methods: 4D{sub vol} CT was performed and characterized on an in-house, programmable respiratory motion phantom containing multiple geometric and morphological ''tumor'' objects over a range of regular and irregular patient breathing traces obtained from 3D fluoroscopy and compared to RCCT. The accuracy of volumetric capture and breathing displacement were evaluated and compared with the ground truth values and with the results reported using RCCT. A motion model was investigated to validate the number of motion samples needed to obtain accurate motion probability density functions (PDF). The impact of 4D image quality on this accuracy was then investigated. Dose measurements using volumetric and conventional scan techniques were also performed and compared. Results: Both conventional and dynamic volume 4DCT methods were capable of estimating the programmed displacement of sinusoidal motion, but patient breathing is known to not be regular, and obvious differences were seen for realistic, irregular motion. The mean RCCT amplitude error averaged at 4 mm (max. 7.8 mm) whereas the 4D{sub vol} CT error stayed below 0.5 mm. Similarly, the average absolute volume error was lower with 4D{sub vol} CT. Under irregular breathing, the 4D{sub vol} CT method provides a close description of the motion PDF (cross-correlation 0.99) and is able to track each object, whereas the RCCT method results in a significantly different PDF from the ground truth, especially for smaller tumors (cross-correlation ranging between 0.04 and 0.69). For the protocols studied, the dose measurements were higher in the 4D{sub vol} CT method (40%), but it was shown that significant mAs reductions can be achieved by a factor of 4-5 while maintaining image quality and accuracy. Conclusions: 4D{sub vol} CT using a scanner with a large cone-angle is a promising alternative for improving the accuracy with which respiration-induced motion can be characterized, particularly for patients with irregular breathing motion. This approach also generates 4DCT image data with a reduced total scan time compared to a RCCT scan, without the need for image binning or external respiration signals within the 16 cm scan length. Scan dose can be made comparable to RCCT by optimization of the scan parameters. In addition, it provides the possibility of measuring breathing motion for more than one breathing cycle to assess stability and obtain a more accurate motion PDF, which is currently not feasible with the conventional RCCT approach.

Coolens, Catherine; Bracken, John; Driscoll, Brandon; Hope, Andrew; Jaffray, David [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9 (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 (Canada) and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

2012-05-15

162

Holographic interferometry in radiation dosimetry, microprocessor assisted  

NASA Astrophysics Data System (ADS)

In this paper the applications of holographic interferometry to ionizing radiation dosimetry are presented. The determination of the accurate value of dose delivered by an ionizing radiation source (released energy per mass unit) is a complex problem which imposes different solutions depending on the experimental parameters and it is solved with a double exposure holographic interferometric method associated with an optoelectronic interface and Z-80 microprocessor. The method can determine the integral absorbed dose as well as the tridimensional distribution of dose in a given volume. The paper presents some results obtained in radiation dosimetry. Different transparent liquids were used as ionizing radiation transducers. Integral dose and spatial dose-distribution were recorded for equivalent tissue liquids and blood plasma. Boundary phenomena, during a irradiation of successive layers of liquids having different atomic numbers, were investigated.

Nicolau, Silvia; Sporea, Dan G.; Niculescu, V. I. R.

1999-08-01

163

Testicular volume is inversely correlated with nurturing-related brain activity in human fathers  

PubMed Central

Despite the well-documented benefits afforded the children of invested fathers in modern Western societies, some fathers choose not to invest in their children. Why do some men make this choice? Life History Theory offers an explanation for variation in parental investment by positing a trade-off between mating and parenting effort, which may explain some of the observed variance in human fathers’ parenting behavior. We tested this hypothesis by measuring aspects of reproductive biology related to mating effort, as well as paternal nurturing behavior and the brain activity related to it. Both plasma testosterone levels and testes volume were independently inversely correlated with paternal caregiving. In response to viewing pictures of one’s own child, activity in the ventral tegmental area—a key component of the mesolimbic dopamine reward and motivation system—predicted paternal caregiving and was negatively related to testes volume. Our results suggest that the biology of human males reflects a trade-off between mating effort and parenting effort, as indexed by testicular size and nurturing-related brain function, respectively. PMID:24019499

Mascaro, Jennifer S.; Hackett, Patrick D.; Rilling, James K.

2013-01-01

164

Computer generated holographic microtags  

DOEpatents

A microlithographic tag comprising an array of individual computer generated holographic patches having feature sizes between 250 and 75 nanometers is disclosed. The tag is a composite hologram made up of the individual holographic patches and contains identifying information when read out with a laser of the proper wavelength and at the proper angles of probing and reading. The patches are fabricated in a steep angle Littrow readout geometry to maximize returns in the -1 diffracted order. The tags are useful as anti-counterfeiting markers because of the extreme difficulty in reproducing them. 5 figs.

Sweatt, W.C.

1998-03-17

165

Precision Holographic Baryons  

SciTech Connect

We overview a holographic QCD based on the D4-D8 string theory model, with emphasis on baryons and nucleon-meson interactions thereof. Baryons are realized as holographic images of Skyrmions, but with much qualitative changes. This allows us to derive, without adjustable parameters, couplings of baryons to the entire tower of spin one mesons and also to pseudoscalar mesons. We find some surprisingly good match against empirical values for nucleons, in particular. Tensor couplings to all axial-vectors and iso-singlet vectors all vanish, while, for {rho} mesons, tensor couplings are found to be dominant. We close with various cautionary comments and speculations.

Yi Piljin [School of Physics, Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of)

2011-10-21

166

Computer generated holographic microtags  

DOEpatents

A microlithographic tag comprising an array of individual computer generated holographic patches having feature sizes between 250 and 75 nanometers. The tag is a composite hologram made up of the individual holographic patches and contains identifying information when read out with a laser of the proper wavelength and at the proper angles of probing and reading. The patches are fabricated in a steep angle Littrow readout geometry to maximize returns in the -1 diffracted order. The tags are useful as anti-counterfeiting markers because of the extreme difficulty in reproducing them.

Sweatt, William C. (Albuquerque, NM)

1998-01-01

167

Cosmological 3-point correlators from holography  

SciTech Connect

We investigate the non-Gaussianity of primordial cosmological perturbations using holographic methods. In particular, we derive holographic formulae that relate all cosmological 3-point correlation functions, including both scalar and tensor perturbations, to stress-energy correlation functions of a holographically dual three-dimensional quantum field theory. These results apply to general single scalar inflationary universes that at late times approach either de Sitter spacetime or accelerating power-law cosmologies. We further show that in Einstein gravity all 3-point functions involving tensors may be obtained from correlators containing only positive helicity gravitons, with the ratios of these to the correlators involving one negative helicity graviton being given by universal functions of momenta, irrespectively of the potential of the scalar field. As a by-product of this investigation, we obtain holographic formulae for the full 3-point function of the stress-energy tensor along general holographic RG flows. These results should have applications in a wider holographic context.

McFadden, Paul; Skenderis, Kostas, E-mail: P.L.McFadden@uva.nl, E-mail: K.Skenderis@uva.nl [Institute for Theoretical Physics, Science Park 904, 1090 GL Amsterdam (Netherlands)

2011-06-01

168

The Nucleon as a Holographic Cheshire Cat  

E-print Network

The Cheshire cat principle emerges naturally from the holographic approach of the nucleon in terms of a bulk instanton. The cat hides in the holographic direction. I briefly review the one-nucleon problem in the holographic limit.

Ismail Zahed

2014-03-13

169

The Nucleon as a Holographic Cheshire Cat  

E-print Network

The Cheshire cat principle emerges naturally from the holographic approach of the nucleon in terms of a bulk instanton. The cat hides in the holographic direction. I briefly review the one-nucleon problem in the holographic limit.

Zahed, Ismail

2014-01-01

170

Holographic Particle Image Velocimetry  

Microsoft Academic Search

The articles in this special feature of Measurement Science and Technology are devoted to an exciting area of fluid metrology pursuing the registration of flow velocities in three dimensions by particle holography—commonly termed holographic particle image velocimetry (HPIV) (Hinsch 2002). Already in 1993 this technique was considered to 'revolutionize the acquisition of velocity data in much the same way as

Klaus D Hinsch; Sven F Herrmann

2004-01-01

171

On inhomogeneous holographic superconductors  

E-print Network

We study a model describing a four-dimensional holographic superconductor whose properties depend non-trivially on a particular spatial direction, namely a Josephson junction. We analyze the parameter dependence of the condensate and compare it to the condensed matter expectations.

Massimo Siani

2011-04-22

172

Holographic recording medium  

NASA Technical Reports Server (NTRS)

A holographic recording medium comprising a conductive substrate, a photoconductive layer and an electrically alterable layer of a linear, low molecular weight hydrocarbon polymer has improved fatigue resistance. An acrylic barrier layer can be interposed between the photoconductive and electrically alterable layers.

Gange, Robert Allen (Inventor)

1977-01-01

173

Pulsed laser holographic video  

Microsoft Academic Search

A holographic video imaging system with acoustooptic media, operated by a pulsed laser is described. The use of a pulse laser allows to get rid of a rotating polygon or a galvano scanner. For angular multiplexing of AOM, a specially designed combination of an acoustooptic scanner and a stripe mirror set (`still polygon') is used. The loading time of CGH

Jung-Young Son; Sergey A. Shestak; Seong-Keun Lee; Hyung-Wook Jeon

1996-01-01

174

Beyond DVD: Holographic Storage  

NSDL National Science Digital Library

InPhase Technologies is exploring holographic storage; however, its goal is to create a device that could be the successor to the DVD. In this article, the potential capabilities and specifications of such a device are discussed. A working prototype has already been demonstrated, paving the way for future commercially viable drives based on the technology.

Whitmer, Clair

175

Multiplexed holographic memory by use of fiber bundle referencing  

Microsoft Academic Search

We propose a volume holographic storage technique, in which a fiber bundle is used to guide the reference beam. Multiplexing is implemented by changing the incident direction of the laser beam upon the fiber bundle in the reference arm. In the technique, we make the system more compact by using a wedge prism to change the direction of the laser

Jiasen Zhang; Tadashi Aruga

2005-01-01

176

Correlation between arterial blood volume obtained by arterial spin labelling and cerebral blood volume in intracranial tumours  

Microsoft Academic Search

Objective To compare measurements of the arterial blood volume (aBV), a perfusion parameter calculated from arterial spin labelling (ASL), and cerebral blood volume (CBV), calculated from dynamic susceptibility contrast (DSC) MRI. In the clinic, CBV is used for grading of intracranial tumours. Materials and methods Estimates of aBV from the model-free ASL technique quantitative STAR labelling of arterial regions (QUASAR)

Danielle van Westen; Esben T. Petersen; Ronnie Wirestam; Roger Siemund; Karin Markenroth Bloch; Freddy Ståhlberg; Isabella M. Björkman-Burtscher; Linda Knutsson

2011-01-01

177

Striatal Volume Increases in Active Methamphetamine-Dependent Individuals and Correlation with Cognitive Performance  

PubMed Central

The effect of methamphetamine (MA) dependence on the structure of the human brain has not been extensively studied, especially in active users. Previous studies reported cortical deficits and striatal gains in grey matter (GM) volume of abstinent MA abusers compared with control participants. This study aimed to investigate structural GM changes in the brains of 17 active MA-dependent participants compared with 20 control participants aged 18–46 years using voxel-based morphometry and region of interest volumetric analysis of structural magnetic resonance imaging data, and whether these changes might be associated with cognitive performance. Significant volume increases were observed in the right and left putamen and left nucleus accumbens of MA-dependent compared to control participants. The volumetric gain in the right putamen remained significant after Bonferroni correction, and was inversely correlated with the number of errors (standardised z-scores) on the Go/No-go task. MA-dependent participants exhibited cortical GM deficits in the left superior frontal and precentral gyri in comparison to control participants, although these findings did not survive correction for multiple comparisons. In conclusion, consistent with findings from previous studies of abstinent users, active chronic MA-dependent participants showed significant striatal enlargement which was associated with improved performance on the Go/No-go, a cognitive task of response inhibition and impulsivity. Striatal enlargement may reflect the involvement of neurotrophic effects, inflammation or microgliosis. However, since it was associated with improved cognitive function, it is likely to reflect a compensatory response to MA-induced neurotoxicity in the striatum, in order to maintain cognitive function. Follow-up studies are recommended to ascertain whether this effect continues to be present following abstinence. Several factors may have contributed to the lack of more substantial cortical and subcortical GM changes amongst MA-dependent participants, including variability in MA exposure variables and difference in abstinence status from previous studies. PMID:24961260

Jan, Reem K.; Lin, Joanne C.; Miles, Sylvester W.; Kydd, Rob R.; Russell, Bruce R.

2012-01-01

178

Holoscopy--holographic optical coherence tomography.  

PubMed

Scanning optical coherence tomography (OCT) is limited in sensitivity and resolution by the restricted focal depth of the confocal detection scheme. Holoscopy, a combination of holography and Fourier-domain full-field OCT, is proposed as a way to detect photons from all depths of a sample volume simultaneously with uniform sensitivity and lateral resolution, even at high NAs. By using the scalar diffraction theory, as frequently applied in digital holographic imaging, we fully reconstruct the object field with depth-invariant imaging quality. In vivo imaging of human skin is demonstrated with an image quality comparable to conventionally scanned OCT. PMID:21725421

Hillmann, Dierck; Lührs, Christian; Bonin, Tim; Koch, Peter; Hüttmann, Gereon

2011-07-01

179

Assembling a holographic scene  

NASA Astrophysics Data System (ADS)

A series of art projects that use multiplex holography as a medium to combine and spatially animate multiple photographic perspectives are presented. Through the process of image collection and compilation into holograms, several concepts are explored. The animate spatial qualities of multiplex holograms are used to express an urban gaze of moving through cites and the multiplicity of perceptual experience. A question of how we understand ourselves to be located and the complexity of this sense is also addressed. The ability to assemble multiple photographic views together into a scene is considered as a method to document the collective experience of event. How these holographic scenes are viewed is compared to the compositional activity, showing both how the holographic medium inspired the compositions and is used as a means of expression.

Mrongovius, Martina

2013-03-01

180

Holographic p -wave superfluid  

NASA Astrophysics Data System (ADS)

In the probe limit, we numerically construct a holographic p -wave superfluid model in the four-dimensional (4D) and five-dimensional (5D) anti-de Sitter black holes coupled to a Maxwell-complex vector field. We find that, for the condensate with the fixed superfluid velocity, the results are similar to the s -wave cases in both 4D and 5D spacetimes. In particular, the Cave of Winds and the phase transition, always being of second order, take place in the 5D case. Moreover, we find that the translating superfluid velocity from second order to first order S/y? increases with the mass squared. Furthermore, for the supercurrent with fixed temperature, the results agree with the Ginzburg-Landau prediction near the critical temperature. In addition, this complex vector superfluid model is still a generalization of the SU(2) superfluid model, and it also provides a holographic realization of the H e3 superfluid system.

Wu, Ya-Bo; Lu, Jun-Wang; Zhang, Wen-Xin; Zhang, Cheng-Yuan; Lu, Jian-Bo; Yu, Fang

2014-12-01

181

Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing (PHASERS)  

NASA Technical Reports Server (NTRS)

A ground-based atmospheric lidar system that utilizes a Holographic Optical Telescope and Scanner has been developed and successfully operated to obtain atmospheric backscatter profiles. The Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing is built around a volume phase reflection Holographic Optical Element. This single optical element both directs and collimates the outgoing laser beam as well as collects, focuses, and filters the atmospheric laser backscatter, while offering significant weight savings over existing telescope mirror technology. Conical scanning is accomplished as the HOE rotates on a turntable sweeping the 1.2 mrad field of view around a 42deg cone. During this technology demonstration, atmospheric aerosol and cloud return signals have been received in both stationary and scanning modes. The success of this program has led to the further development of this technology for integration into airborne and eventually satellite earth observing scanning lidar telescopes.

Guerra, David V.; Schwemmer, Geary K.; Wooten, Albert D., Jr.; Chaudhuri, Sandipan S.; Wilkerson, Thomas D.

1995-01-01

182

Application of holographic optical techniques to bulk memory.  

NASA Technical Reports Server (NTRS)

Current efforts to exploit the spatial redundancy and built-in imaging of holographic optical techniques to provide high information densities without critical alignment and tight mechanical tolerances are reviewed. Read-write-erase in situ operation is possible but is presently impractical because of limitations in available recording media. As these are overcome, it should prove feasible to build holographic bulk memories with mechanically replaceable hologram plates featuring very fast (less than 2 microsec) random access to large (greater than 100 million bit) data blocks and very high throughput (greater than 500 Mbit/sec). Using volume holographic storage it may eventually be possible to realize random-access mass memories which require no mechanical motion and yet provide very high capacity.

Anderson, L. K.

1971-01-01

183

Holographic Neutron Stars  

E-print Network

We construct in the context of the AdS/CFT correspondence degenerate composite operators in the conformal field theory that are holographically dual to degenerate stars in anti de Sitter space. We calculate the effect of the gravitational back-reaction using the Tolman-Oppenheimer-Volkoff equations, and determine the "Chandrasekhar limit" beyond which the star undergoes gravitational collapse towards a black hole.

Jan de Boer; Kyriakos Papadodimas; Erik Verlinde

2009-07-23

184

Flowing holographic anyonic superfluid  

NASA Astrophysics Data System (ADS)

We investigate the flow of a strongly coupled anyonic superfluid based on the holographic D3-D7' probe brane model. By analyzing the spectrum of fluctuations, we find the critical superfluid velocity, as a function of the temperature, at which the flow stops being dissipationless when flowing past a barrier. We find that at a larger velocity the flow becomes unstable even in the absence of a barrier.

Jokela, Niko; Lifschytz, Gilad; Lippert, Matthew

2014-10-01

185

Baryons in holographic QCD  

SciTech Connect

We study baryons in holographic QCD with D4/D8/D8 multi-D-brane system. In holographic QCD, the baryon appears as a topologically nontrivial chiral soliton in a four-dimensional effective theory of mesons. We call this topological soliton brane-induced Skyrmion. Some review of D4/D8/D8 holographic QCD is presented from the viewpoints of recent hadron physics and QCD phenomenologies. A four-dimensional effective theory with pions and {rho} mesons is uniquely derived from the non-Abelian Dirac-Born-Infeld (DBI) action of D8 brane with D4 supergravity background at the leading order of large N{sub c}, without small amplitude expansion of meson fields to discuss chiral solitons. For the hedgehog configuration of pion and {rho}-meson fields, we derive the energy functional and the Euler-Lagrange equation of brane-induced Skyrmion from the meson effective action induced by holographic QCD. Performing the numerical calculation, we obtain the soliton solution and figure out the pion profile F(r) and the {rho}-meson profile G-tilde(r) of the brane-induced Skyrmion with its total energy, energy density distribution, and root-mean-square radius. These results are compared with the experimental quantities of baryons and also with the profiles of standard Skyrmion without {rho} mesons. We analyze interaction terms of pions and {rho} mesons in brane-induced Skyrmion, and find a significant {rho}-meson component appearing in the core region of a baryon.

Nawa, Kanabu; Suganuma, Hideo; Kojo, Toru [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2007-04-15

186

Holographic Plossl Retroreflectors  

NASA Technical Reports Server (NTRS)

Holographic retroreflectors that function equivalently to Plossl eyepieces have been developed and used in free-space optical communication systems that utilize laser beams. Plossl eyepieces are well known among telescope designers. They have been adopted for use a retroreflectors and as focusing elements (for reception) and collimating elements (for transmission) in optical communication systems. A retro-reflector that incorporates a Plossl eyepiece is termed a cat's-eye retroreflector.

Waluschka, Eugene

2006-01-01

187

Holographic phase transition in a noncritical holographic model  

SciTech Connect

We consider a holographic model constructed from the intersecting brane configuration D4-D4/D4 in noncritical string theory. We study the chiral phase diagram of this holographic QCD-like model with a finite baryon chemical potential through the supergravity dual approximation.

Cui Shengliang; Gao Yihong [Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Science, P.O. Box 2735, Beijing 100080 (China); Xu Weishui [Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of); Center for Quantum Spacetime, Sogang University, Seoul 121-742 (Korea, Republic of)

2010-01-15

188

Hydrodynamics of Holographic Superconductors  

E-print Network

We study the poles of the retarded Green functions of a holographic superconductor. The model shows a second order phase transition where a charged scalar operator condenses and a U(1) symmetry is spontaneously broken. The poles of the holographic Green functions are the quasinormal modes in an AdS black hole background. We study the spectrum of quasinormal frequencies in the broken phase, where we establish the appearance of a massless or hydrodynamic mode at the critical temperature as expected for a second order phase transition. In the broken phase we find the pole representing second sound. We compute the speed of second sound and its attenuation length as function of the temperature. In addition we find a pseudo diffusion mode, whose frequencies are purely imaginary but with a non-zero gap at zero momentum. This gap goes to zero at the critical temperature. As a technical side result we explain how to calculate holographic Green functions and their quasinormal modes for a set of operators that mix under the RG flow.

Irene Amado; Matthias Kaminski; Karl Landsteiner

2009-06-17

189

Hydrodynamics of Holographic Superconductors  

E-print Network

We study the poles of the retarded Green functions of a holographic superconductor. The model shows a second order phase transition where a charged scalar operator condenses and a U(1) symmetry is spontaneously broken. The poles of the holographic Green functions are the quasinormal modes in an AdS black hole background. We study the spectrum of quasinormal frequencies in the broken phase, where we establish the appearance of a massless or hydrodynamic mode at the critical temperature as expected for a second order phase transition. In the broken phase we find the pole representing second sound. We compute the speed of second sound and its attenuation length as function of the temperature. In addition we find a pseudo diffusion mode, whose frequencies are purely imaginary but with a non-zero gap at zero momentum. This gap goes to zero at the critical temperature. As a technical side result we explain how to calculate holographic Green functions and their quasinormal modes for a set of operators that mix under...

Amado, Irene; Landsteiner, Karl

2009-01-01

190

Correlation  

NSDL National Science Digital Library

This chapter will discuss the concept of correlation , which is used in later chapters that will explain the concepts of validity and reliability. Here, the authors introduce the Pearson correlation coefficient, a statistic that is used with ratio

Edwin P. Christmann

2008-11-01

191

Holographic portrait of Ronald Reagan  

Microsoft Academic Search

The first holographic portrait of a President of the United States of America was recorded on 24 May 1991 in Santa Barbara, Calif. Ronald Reagan was the subject. The event was the first in a project that began some five years ago with the aim of producing an archive of Presidential pulsed holographic portraits. The authors discuss the inception and

Hans I. Bjelkhagen; Rebecca E. Deem; John Landry; Michel E. Marhic; Fred D. Unterseher

1992-01-01

192

Determination of correlation between backflow volume and mitral valve leaflet young modulus from two dimensional echocardiogram images  

NASA Astrophysics Data System (ADS)

Mitral valve prolapse without proper monitoring might lead to a severe mitral valve failure which eventually leads to a sudden death. Additional information on the mitral valve leaflet condition against the backflow volume would be an added advantage to the medical practitioner for their decision on the patients' treatment. A study on two dimensional echocardiography images has been conducted and the correlations between the backflow volume of the mitral regurgitation and mitral valve leaflet Young modulus have been obtained. Echocardiogram images were analyzed on the aspect of backflow volume percentage and mitral valve leaflet dimensions on different rates of backflow volume. Young modulus values for the mitral valve leaflet were obtained by using the principle of elastic deflection and deformation on the mitral valve leaflet. The results show that the backflow volume increased with the decrease of the mitral valve leaflet Young modulus which also indicate the condition of the mitral valve leaflet approaching failure at high backflow volumes. Mitral valve leaflet Young modulus values obtained in this study agreed with the healthy mitral valve leaflet Young modulus from the literature. This is an initial overview of the trend on the prediction of the behaviour between the fluid and the structure of the blood and the mitral valve which is extendable to a larger system of prediction on the mitral valve leaflet condition based on the available echocardiogram images.

Jong, Rudiyanto P.; Osman, Kahar; Adib, M. Azrul Hisham M.

2012-06-01

193

Characteristics of a dynamic holographic sensor for shape control of a large reflector  

NASA Technical Reports Server (NTRS)

Design of a distributed holographic interferometric sensor for measuring the surface displacement of a large segmented reflector is proposed. The reflector's surface is illuminated by laser light of two wavelengths and volume holographic gratings are formed in photorefractive crystals of the wavefront returned from the surface. The sensor is based on holographic contouring with a multiple frequency source. It is shown that the most stringent requirement of temporal stability affects both the temporal resolution and the dynamic range. Principal factor which limit the sensor performance include the response time of photorefractive crystal, laser power required to write a hologram, and the size of photorefractive crystal.

Welch, Sharon S.; Cox, David E.

1991-01-01

194

Holographic rugate structures for x-ray optics applications  

SciTech Connect

Physical Optics Corporation (POC) has proposed and investigated a novel approach to x-ray optics during this DOE-sponsored three-year program, based on our well-established technologies in volume holography and holographic materials. With these technologies, a majority of conventional XUV optical elements, such as uniform and nonuniform gratings/multilayers, lenses, slanted (non-Snellian) mirrors, Fresnel zone-plates, concentrators/collimators, beam splitters, Fabry-Perot etalons, and binary optical elements, can be fabricated using a unified, low cost process. Furthermore, volume holography offer nonconventional optical elements, such as x-ray holographic optical elements (HOEs) with any desirable wavefront formation characteristics and multiple gratings multiplexed in the same volume to perform different operations for different wavelengths, that are difficult or even impossible to produce with the existing technologies.

Jannson, T.; Savant, G.

1990-03-19

195

Does Low Individual Operator Coronary Interventional Procedural Volume Correlate With Worse Institutional Procedural Outcome?  

Microsoft Academic Search

Objectives. To assess the relation between individual operator coronary interventional volume and incidence of complications, the in-hospital outcome at a single, moderate volume urban academic center was prospectively collected over a 3-year period.Background. A minimum of 75 coronary interventions\\/operator per year may be required in the future to obtain formal certification. However, few data exist regarding individual operator volumes and

Lloyd W Klein; Gary L Schaer; James E Calvin; Brian Palvas; Jill Allen; Joshua Loew; Eugene Uretz; Joseph E Parrillo

1997-01-01

196

Son-Yamamoto relation and holographic renormalization group flows  

NASA Astrophysics Data System (ADS)

Motivated by the Son-Yamamoto (SY) relation, which connects the three-point and two-point correlators, we consider the holographic renormalization group (RG) flows in the bottom-up approach to holographic QCD via the Hamilton-Jacobi equation with respect to the radial coordinate. It is shown that the SY relation is diagonal with respect to the RG flow in the 5D Yang-Mills-Chern-Simons model, while the RG equation acquires an inhomogeneous term in the model with an additional scalar field, which encodes the chiral condensate.

Dubinkin, O.; Gorsky, A.; Milekhin, A.

2015-03-01

197

Correlation of the Peach Springs Tuff, a large-volume Miocene ignimbrite sheet in California and Arizona ( USA).  

USGS Publications Warehouse

The Peach Springs Tuff is a distinctive early Miocene ignimbrite deposit that was first recognized in western Arizona. Recent field studies and phenocryst analyses indicate that adjacent outcrops of similar tuff in the central and eastern Mojave Desert may be correlative. This proposed correlation implies that outcrops of the tuff are scattered over an area of at least 35 000 km2 from the western Colorado Plateau to Barstow, California, and that the erupted volume, allowing for posteruption crustal extension, was at least several hundred cubic kilometres. Thus, the Peach Springs Tuff may be a regional stratigraphic marker, useful for determining regional paleogeography and the time and extent of Tertiary crustal extension. -Authors

Glazner, A.F.; Nielson, J.E.; Howard, K.A.; Miller, D.M.

1986-01-01

198

Elastic stiffness characterization using three-dimensional full-field deformation obtained with optical coherence tomography and digital volume correlation.  

PubMed

This paper presents a methodology for stiffness identification from depth-resolved three-dimensional (3-D) full-field deformation fields. These were obtained by performing digital volume correlation on optical coherence tomography volume reconstructions of silicone rubber phantoms. The effect of noise and reconstruction uncertainties on the performance of the correlation algorithm was first evaluated through stationary and rigid body translation tests to give an indication of the minimum strain that can be reliably measured. The phantoms were then tested under tension, and the 3-D deformation fields were used to identify the elastic constitutive parameters using a 3-D manually defined virtual fields method. The identification results for the cases of uniform and heterogeneous strain fields were compared with those calculated analytically through the constant uniaxial stress assumption, showing good agreement. PMID:24346854

Fu, Jiawei; Pierron, Fabrice; Ruiz, Pablo D

2013-12-01

199

Elastic stiffness characterization using three-dimensional full-field deformation obtained with optical coherence tomography and digital volume correlation  

NASA Astrophysics Data System (ADS)

This paper presents a methodology for stiffness identification from depth-resolved three-dimensional (3-D) full-field deformation fields. These were obtained by performing digital volume correlation on optical coherence tomography volume reconstructions of silicone rubber phantoms. The effect of noise and reconstruction uncertainties on the performance of the correlation algorithm was first evaluated through stationary and rigid body translation tests to give an indication of the minimum strain that can be reliably measured. The phantoms were then tested under tension, and the 3-D deformation fields were used to identify the elastic constitutive parameters using a 3-D manually defined virtual fields method. The identification results for the cases of uniform and heterogeneous strain fields were compared with those calculated analytically through the constant uniaxial stress assumption, showing good agreement.

Fu, Jiawei; Pierron, Fabrice; Ruiz, Pablo D.

2013-12-01

200

Holographic diffraction gratings with enhanced sensitivity based on epoxy-resin photopolymers  

Microsoft Academic Search

Photopolymers are interesting materials to obtain high-quality performance for the volume holographic data storage with a low noise and high diffraction efficiency. In this paper, the recording of holographic diffraction gratings with a spatial frequency of 1285lines\\/mm in photopolymerizable epoxy resin materials is experimentally demonstrated. Diffraction efficiency near 92% and an energetic sensitivity of 11.7 x 10-3cm2\\/J are achieved by

Yong-Cheol Jeong; Seungwoo Lee; Jung-Ki Park

2007-01-01

201

High-density recording of full-color full-parallax holographic stereogram  

Microsoft Academic Search

We demonstrate a high quality 3D image reproduced by a full-color, full-parallax holographic stereogram (HS) with high-density light-ray recording. The full-parallax HS is produced by a holographic 3D printer, which is an electronic controlled optical system for automatic recording. The HS consists of a 2D array structure of volume type elementary holograms, and full-parallax 3D image can be observed under

Shingo Maruyama; Yuji Ono; Masahiro Yamaguchi

2008-01-01

202

Phase-conjugate holographic system for high-resolution particle-image velocimetry  

NASA Astrophysics Data System (ADS)

A holographic particle-image velocimeter is proposed for 3-D fluids velocity fields study. A low-f-number optical arrangement is used that records two views of flow volume at two times on a single holographic plate, and one at a time reconstructs those views using phase-conjugate multiplexed image reconstruction. Improvements in depth of focus, signal-to-noise ratio, and image resolution are reported.

Barnhart, Donald H.; Adrian, Ronald J.; Papen, George C.

1994-10-01

203

Water-soluble gases as partitioning tracers to investigate the pore volume–transmissivity correlation in a fracture  

Microsoft Academic Search

Hydraulically equivalent fractures may show striking differences when a gas-migration experiment is performed because of the different correlations between transmissivity, pore volume and entry pressure. We numerically simulate gas migration between injection and extraction boreholes in a parallel plate fracture with a heterogeneous fault gouge, in a rough-walled fracture filled with homogeneous material, and in a rough-walled empty fracture. The

Ivan Lunati; Wolfgang Kinzelbach

2004-01-01

204

Holographic movie: the first step to holographic video  

NASA Astrophysics Data System (ADS)

Holographic movies can be seen as a tool to estimate the picture quality of moving holographic images as a step towards holographic television. With this in mind, we have developed an experimental holographic movie system and produced a short duration 3D movie. A number of dolls and moving objects were positioned within a background and illuminated with a He-Ne laser (632.8 nm). Conventional film-making techniques were used during holographic recording to create a more attractive sequence. The techniques included stop-motion, tracking, enhanced depth perception, up-shots, and overlaps. A series of 300 Fresnel type holograms was recorded on standard holographic films. An interesting technical point is that the film was 10 mm high by 200 mm wide. After developing, the films were sandwiched between two rigid acrylic drums (about 1 m in diameter). The drum is rotated and the films illuminated with the He-Ne laser. The display speed can be varied from 6 to 24 frames per second. The films are viewed through a window. Even though this prototype is relatively primitive the resulting holographic movie is quite effective. Several interesting effects were noted. For example, it was found that objects in the movie must not rapidly shift their depth because the human eye cannot track them is they do.

Higuchi, Kazuhito; Ishikawa, Jun; Hiyama, Shigeo

1992-05-01

205

Holographic Labeling And Reading Machine For Authentication And Security Appications  

DOEpatents

A holographic security label and automated reading machine for marking and subsequently authenticating any object such as an identification badge, a pass, a ticket, a manufactured part, or a package is described. The security label is extremely difficult to copy or even to read by unauthorized persons. The system comprises a holographic security label that has been created with a coded reference wave, whose specification can be kept secret. The label contains information that can be extracted only with the coded reference wave, which is derived from a holographic key, which restricts access of the information to only the possessor of the key. A reading machine accesses the information contained in the label and compares it with data stored in the machine through the application of a joint transform correlator, which is also equipped with a reference hologram that adds additional security to the procedure.

Weber, David C. (Rancho Santa Margarita, CA); Trolinger, James D. (Costa Mesa, CA)

1999-07-06

206

Anatomical structural network analysis of human brain using partial correlations of gray matter volumes  

Microsoft Academic Search

Structural connectivity in human brain has been studied by modeling the statistical dependence between features of cortical regions, such as gray matter thickness. Statistical correlations between gray matter thickness have been mainly used as a metric to study this dependence. In this paper, we propose the use of partial correlations instead of Pearson correlation for inferring the brain structural connectivity

Anand A. Joshi; Shantanu H. Joshi; Ivo D. Dinov; David W. Shattuck; Richard M. Leahy; Arthur W. Toga

2010-01-01

207

Correcting Correlations When Predicting Success in College. IR Applications. Volume 31  

ERIC Educational Resources Information Center

Critics of testing for admission purposes cite the moderate correlations of admissions test scores with success in college. In response, this study applies formulas from classical measurement theory to observed correlations to correct for restricted variances in predictor and success variables. Estimates of the correlations in the population of…

Saupe, Joe L.; Eimers, Mardy T.

2011-01-01

208

Holographic SIS Josephson Junction  

E-print Network

We construct a holographic model for the superconductor-insulator-superconductor (SIS) Josephson junction at zero temperature by considering a complex scalar field coupled with a Maxwell field in the four-dimensional anti-de Sitter soliton background. From the gravity side we reproduce the sine relation between the Josephson current and the phase difference across the junction. We also study the dependence of the maximal current on the dimension of the condensate operator and on the width of the junction, and obtain expected results.

Yong-Qiang Wang; Yu-Xiao Liu; Rong-Gen Cai; Shingo Takeuchi; Hai-Qing Zhang

2012-09-23

209

Exploring colourful holographic superconductors  

E-print Network

We explore a class of holographic superconductors built using non-abelian condensates on probe branes in conformal and non-conformal backgrounds. These are shown to exhibit behaviour of the specific heat which resembles that of heavy fermion compounds in the superconducting phase. Instead of showing BCS-like exponential behaviour, the specific heat is polynomial in the temperature. It exhibits a jump at the critical temperature, in agreement with real-world superconductors. We also analyse the behaviour of the energy gap and the AC and DC conductivities, and find that the systems can be either semi-conducting or metallic just above the critical temperature.

Kasper Peeters; Jonathan Powell; Marija Zamaklar

2009-07-09

210

Introduction to Holographic Superconductors  

E-print Network

These lectures give an introduction to the theory of holographic superconductors. These are superconductors that have a dual gravitational description using gauge/gravity duality. After introducing a suitable gravitational theory, we discuss its properties in various regimes: the probe limit, the effects of backreaction, the zero temperature limit, and the addition of magnetic fields. Using the gauge/gravity dictionary, these properties reproduce many of the standard features of superconductors. Some familiarity with gauge/gravity duality is assumed. A list of open problems is included at the end.

Gary T. Horowitz

2010-02-17

211

Models of Holographic superconductivity  

E-print Network

We construct general models for holographic superconductivity parametrized by three couplings which are functions of a real scalar field and show that under general assumptions they describe superconducting phase transitions. While some features are universal and model independent, important aspects of the quantum critical behavior strongly depend on the choice of couplings, such as the order of the phase transition and critical exponents of second-order phase transitions. In particular, we study a one-parameter model where the phase transition changes from second to first order above some critical value of the parameter and a model with tunable critical exponents.

Francesco Aprile; Jorge G. Russo

2010-01-21

212

Holographic Charged Renyi Entropies  

E-print Network

We construct a new class of entanglement measures by extending the usual definition of Renyi entropy to include a chemical potential. These charged Renyi entropies measure the degree of entanglement in different charge sectors of the theory and are given by Euclidean path integrals with the insertion of a Wilson line encircling the entangling surface. We compute these entropies for a spherical entangling surface in CFT's with holographic duals, where they are related to entropies of charged black holes with hyperbolic horizons. We also compute charged Renyi entropies in free field theories.

Alexandre Belin; Ling-Yan Hung; Alexander Maloney; Shunji Matsuura; Robert C. Myers; Todd Sierens

2015-01-20

213

Introduction to Holographic Superconductor Models  

E-print Network

In the last years it has been shown that some properties of strongly coupled superconductors can be potentially described by classical general relativity living in one higher dimension, which is known as holographic superconductors. This paper gives a quick and introductory overview of some holographic superconductor models with s-wave, p-wave and d-wave orders in the literature from point of view of bottom-up, and summarizes some basic properties of these holographic models in various regimes. The competition and coexistence of these superconductivity orders are also studied in these superconductor models.

Rong-Gen Cai; Li Li; Li-Fang Li; Run-Qiu Yang

2015-02-02

214

Introduction to Holographic Superconductor Models  

E-print Network

In the last years it has been shown that some properties of strongly coupled superconductors can be potentially described by classical general relativity living in one higher dimension, which is known as holographic superconductors. This paper gives a quick and introductory overview of some holographic superconductor models with s-wave, p-wave and d-wave orders in the literature from point of view of bottom-up, and summarizes some basic properties of these holographic models in various regimes. The competition and coexistence of these superconductivity orders are also studied in these superconductor models.

Rong-Gen Cai; Li Li; Li-Fang Li; Run-Qiu Yang

2015-03-12

215

Conically scanned holographic lidar telescope  

NASA Technical Reports Server (NTRS)

An optical scanning device utilizing a source of optical energy such as laser light backscattered from the earth's atmosphere or transmitted outward as in a lidar, a rotating holographic optical element having an axis of rotation perpendicular to the plane of its substrate, and having a stationary focus which may or may not be located on its axis of rotation, with the holographic optical element diffracting the source of optical energy at an angle to its rotation axis enabling a conical scanning area and a motor for supporting and rotating the rotating holographic optical element, is described.

Schwemmer, Geary (inventor)

1993-01-01

216

Introduction to Holographic Superconductor Models  

E-print Network

In the last years it has been shown that some properties of strongly coupled superconductors can be potentially described by classical general relativity living in one higher dimension, which is known as holographic superconductors. This paper gives a quick and introductory overview of some holographic superconductor models with s-wave, p-wave and d-wave orders in the literature from point of view of bottom-up, and summarizes some basic properties of these holographic models in various regimes. The competition and coexistence of these superconductivity orders are also studied in these superconductor models.

Cai, Rong-Gen; Li, Li-Fang; Yang, Run-Qiu

2015-01-01

217

Engineering holographic graphene  

SciTech Connect

We present a top-down string theory holographic model of strongly interacting relativistic 2 + 1-dimensional fermions, paying careful attention to the discrete symmetries of parity and time reversal invariance. Our construction is based on probe D7-branes in AdS{sub 5} Multiplication-Sign S{sup 5}, stabilized by internal fluxes. We find three solutions, a parity and time reversal invariant conformal field theory which can be viewed as a particular deformation of Coulomb interacting graphene, a parity and time reversal violating but gapless field theory and a system with a parity and time reversal violating charge gap. We show that the Chern-Simons-like electric response function, which is generated perturbatively at one-loop order by parity violating fermions and which is protected by a no-renormalization theorem at orders beyond one loop, indeed appears with the correctly quantized coefficient in the charge gapped theory. In the gapless parity violating solution, the Chern-Simons response function obtains quantum corrections which we compute in the holographic theory.

Semenoff, Gordon W. [Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T 1Z1 (Canada)

2012-09-24

218

Holographic Solar Photon Thrusters  

NASA Technical Reports Server (NTRS)

A document discusses a proposal to incorporate holographic optical elements into solar photon thrusters (SPTs). First suggested in 1990, SPTs would be systems of multiple reflective, emissive, and absorptive surfaces (solar sails) that would be attached to spacecraft orbiting the Earth to derive small propulsive forces from radiation pressures. An SPT according to the proposal would include, among other things, a main sail. One side of the sail would be highly emissive and would normally face away from the Earth. The other side would be reflective and would be covered by white-light holographic images that would alternately become reflective, transmissive, and absorptive with small changes in the viewing angle. When the spacecraft was at a favorable orbital position, the main sail would be oriented to reflect sunlight in a direction to maximize the solar thrust; when not in a favorable position, the main sail would be oriented to present a substantially absorptive/emissive aspect to minimize the solar drag. By turning the main sail slightly to alternate between the reflective and absorptive/ emissive extremes, one could achieve nearly a doubling or halving of the radiational momentum transfer and, hence, of the solar thrust.

Johnson, Les; Matloff, Greg

2006-01-01

219

Generalized Holographic Dark Energy  

E-print Network

In the original holographic dark energy (HDE) model, the dark energy density is proposed to be $\\rho_{de} = 3c^2M^2_{pl}L^{-2}$, with $c$ is a dimensionless constant characterizing the properties of the HDE. In this work, we propose the generalized holographic dark energy (GHDE) model by considering the parameter $c$ as a redshift-dependent function $c(z)$. We derive all the physical quantities of the GHDE model analytically, and fit the $c(z)$ by trying four kinds of parametrizations. The cosmological constraints of the $c(z)$ are obtained from the joint analysis of the present SNLS3+BAO+CMB+$H_0$ data. We find that, compared with the original HDE model, the GHDE models can provide a better fit to the data. For example, the GHDE model with JBP-type $c(z)$ can reduce the $\\chi^2_{min}$ of the HDE model by 2.16. We also find that, unlike the original HDE model with a phantom-like behavior in the future, the GHDE models can present many more different possibilities, i.e., it allows the GHDE in the future to be ...

Zhang, Zhenhui; Li, Xiao-Dong; Wang, Shuang; Zhang, Wen-Shuai

2012-01-01

220

Engineering holographic graphene  

NASA Astrophysics Data System (ADS)

We present a top-down string theory holographic model of strongly interacting relativistic 2 + 1-dimensional fermions, paying careful attention to the discrete symmetries of parity and time reversal invariance. Our construction is based on probe D7-branes in AdS5 × S5, stabilized by internal fluxes. We find three solutions, a parity and time reversal invariant conformal field theory which can be viewed as a particular deformation of Coulomb interacting graphene, a parity and time reversal violating but gapless field theory and a system with a parity and time reversal violating charge gap. We show that the Chern-Simons-like electric response function, which is generated perturbatively at one-loop order by parity violating fermions and which is protected by a no-renormalization theorem at orders beyond one loop, indeed appears with the correctly quantized coefficient in the charge gapped theory. In the gapless parity violating solution, the Chern-Simons response function obtains quantum corrections which we compute in the holographic theory.

Semenoff, Gordon W.

2012-10-01

221

Reduced volume in the anterior internal capsule but its maintained correlation with the frontal gray matter in subjects at ultra-high risk for psychosis.  

PubMed

The anterior limb of the internal capsule (ALIC), which interconnects with the frontal cortex and thalamus, is volumetrically altered in schizophrenia patients. However, it is unclear whether an abnormal ALIC volume is apparent prior to the onset of schizophrenia and whether this aberrant ALIC volume is related to the frontal gray matter in individuals at ultra-high risk (UHR) for psychosis. We used magnetic resonance imaging of 43 UHR subjects, 36 schizophrenia patients, and 42 healthy controls to investigate manually traced ALIC volumes. Additionally, we evaluated the correlation between the ALIC volume and the frontal gray matter. Significantly reduced ALIC volumes were observed in the UHR and schizophrenia groups compared to the healthy controls. However, the volume of the frontal gray matter was decreased only in the schizophrenia group. A positive correlation between the volumes in the ALIC and frontal gray matter found in healthy controls was maintained only in UHR subjects. In addition, a negative correlation between the total scores on the Positive and Negative Syndrome Scale and the ALIC volumes was observed only in schizophrenia patients. An aberrant ALIC volume but its maintained correlation with the interconnecting frontal lobe was present prior to the onset of full psychosis, indicating the prodromal phase of psychosis. PMID:23217576

Han, Hyun Jung; Jung, Wi Hoon; Jang, Joon Hwan; Hwang, Jae Yeon; Kim, Sung Nyun; Byun, Min Soo; Lee, Yoon Joo; Choi, Chi-Hoon; Kwon, Jun Soo

2012-11-30

222

Sub-50nm extreme ultraviolet holographic imaging  

NASA Astrophysics Data System (ADS)

Imaging tools for nanoscicence involving sub-100-nm scale objects have been dominated by atomic force microscopy (AFM), scanning tunneling microscopy (STM), and electron microscopy (SEM, TEM). These imaging techniques have contributed substantially to the development of nanoscience, providing a very powerful diagnostic tool capable of obtaining images with atomic resolution or as a subsidiary mechanism to arrange or modify surfaces also at the atomic scale [1,2]. However, some important problems have persisted traditional nanoscale imaging techniques. For example when scanning a nanometer size object that is not attached rigidly to a surface the interaction with the tip significantly perturbs the specimen degrading or eventually precluding the image acquisition. Electron microscopy often requires surface preparation, consisting of metallization of the sample to avoid surface charging. Additionally the metallization of the sample may alter its characteristics and also limits the resolution. In both cases, if the sample is large (millimeters in size) due to the limited field of view, the image obtained with these conventional methods is only representative of a very small portion of the object. Wavelength-limited holographic imaging using carbon nanotubes as the test object with a table-top extreme ultraviolet (EUV) laser operating at 46.9 nm will be discussed. The resolution achieved in this imaging is evaluated with a rigorous correlation image analysis and confirmed with the conventional knife-edge test. The nano-holography presented requires no optics or critical beam alignment; thus the hologram recording scheme is very simple and does not need special sample preparation. In holography, image contrast requires absorption to provide scattering by the illuminating beam. The EUV laser wavelength employed in this experiment (46.9nm) is advantageous because carbon based materials typically exhibit very small attenuation lengths, around 25 nm. The high absorption of even small object volumes produces high optical contrasts. The short attenuation length thus enables nearly full contrast for most objects without applying forces to the imaged objects, no charge buildup, and without the need for complicated sample preparation. Additionally this simple technique allows to image macroscopic size objects, several millimeters square with arbitrary shape while simultaneously sustaining across the image sub-50 nm spatial resolution. This characteristic is equivalent to storing data at a density rate of ~0.3 Tbit per square inch over large areas, and represents a simple demonstration of a method that allows permanently dense storage of a large amount of data.

Wachulak, P. W.; Marconi, M. C.; Bartels, R. A.; Menoni, C. S.; Rocca, J. J.

2009-05-01

223

Adventures in Holographic Dimer Models  

SciTech Connect

We abstract the essential features of holographic dimer models, and develop several new applications of these models. Firstly, semi-holographically coupling free band fermions to holographic dimers, we uncover novel phase transitions between conventional Fermi liquids and non-Fermi liquids, accompanied by a change in the structure of the Fermi surface. Secondly, we make dimer vibrations propagate through the whole crystal by way of double trace deformations, obtaining nontrivial band structure. In a simple toy model, the topology of the band structure experiences an interesting reorganization as we vary the strength of the double trace deformations. Finally, we develop tools that would allow one to build, in a bottom-up fashion, a holographic avatar of the Hubbard model.

Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Karch, Andreas; /Washington U., Seattle; Yaida, Sho; /Stanford U., Phys. Dept.

2011-08-12

224

Holographic microscopy studies of emulsions  

NASA Technical Reports Server (NTRS)

A holographic microscopy system that records and observes the dynamic properties of separation of dispersed immiscible fluids is described. The holographic construction system and reconstruction system that were used to obtain particle size and distribution information from the holograms are discussed. The holographic microscopy system is used to observed the phase separating processes in immiscible fluids that were isothermally cooled into the two phase region. Nucleation, growth rates, coalescence, and particle motion are successfully demonstrated with this system. Thus a holographic particle sizing system with a resolution of 2 micrometers and a field of view of 100 cu cm was developed that provides the capability of testing the theories of separating immiscible fluids for particle number densities in the range of 10 to 10 to the 7th power particles.

Witherow, W. K.

1981-01-01

225

Modelflow Estimates of Stroke Volume Do Not Correlate With Doppler Ultrasound Estimates During Upright Posture  

NASA Technical Reports Server (NTRS)

Orthostatic intolerance affects 60-80% of astronauts returning from long-duration missions, representing a significant risk to completing mission-critical tasks. While likely multifactorial, a reduction in stroke volume (SV) represents one factor contributing to orthostatic intolerance during stand and head up tilt (HUT) tests. Current measures of SV during stand or HUT tests use Doppler ultrasound and require a trained operator and specialized equipment, restricting its use in the field. BeatScope (Finapres Medical Systems BV, The Netherlands) uses a modelflow algorithm to estimate SV from continuous blood pressure waveforms in supine subjects; however, evidence supporting the use of Modelflow to estimate SV in subjects completing stand or HUT tests remain scarce. Furthermore, because the blood pressure device is held extended at heart level during HUT tests, but allowed to rest at the side during stand tests, changes in the finger arterial pressure waveform resulting from arm positioning could alter modelflow estimated SV. The purpose of this project was to compare Doppler ultrasound and BeatScope estimations of SV to determine if BeatScope can be used during stand or HUT tests. Finger photoplethysmography was used to acquire arterial pressure waveforms corrected for hydrostatic finger-to-heart height using the Finometer (FM) and Portapres (PP) arterial pressure devices in 10 subjects (5 men and 5 women) during a stand test while simultaneous estimates of SV were collected using Doppler ultrasound. Measures were made after 5 minutes of supine rest and while subjects stood for 5 minutes. Next, SV estimates were reacquired while each arm was independently raised to heart level, a position similar to tilt testing. Supine SV estimates were not significantly different between all three devices (FM: 68+/-20, PP: 71+/-21, US: 73+/-21 ml/beat). Upon standing, the change in SV estimated by FM (-18+/-8 ml) was not different from PP (-21+/-12), but both were significantly less than US (-37+/-16 ml, p<.05). Raising finger BP devices to heart level caused no significant change in SV measured with any of the devices (FM: 1.5+/-19, PP: 1.7+/-26, US: 0.5+/-6), although variability was 3-6x greater as assessed by both blood pressure devices compared to US. Retrospective analysis of blood pressure data to assess SV in 11 supine subjects revealed significantly different estimates between methods (FM: 95+/-17, US: 75+/-32, p<.05), but the change in SV resulting from HUT was similar between methods (FM: -37+/-9, US: -40+/-18 ml). However, the correlation coefficient determined from pairs of SV estimated by US and FM was weak (r2=0.03). These data suggest Modelflow cannot be used in lieu of Doppler ultrasound to estimate SV during stand or HUT tests. Further investigation should focus on identifying factors contributing to differences between these measurement techniques in order to make use of a simple method for assessing beat-by-beat changes in SV during postural changes, especially during field testing.

Ferguson, Connor R.; Lee, Stuart M. C.; Stenger, Michael B.; Platts, Steven H.; Laurie, Steven S.

2014-01-01

226

Onboard utilization of ground control points for image correction. Volume 4: Correlation analysis software design  

NASA Technical Reports Server (NTRS)

The software utilized for image correction accuracy measurement is described. The correlation analysis program is written to allow the user various tools to analyze different correlation algorithms. The algorithms were tested using LANDSAT imagery in two different spectral bands. Three classification algorithms are implemented.

1981-01-01

227

Holographic framework for eternal inflation  

Microsoft Academic Search

In this paper we provide some circumstantial evidence for a holographic duality between bubble nucleation in an eternally inflating universe and a Euclidean conformal field theory (CFT). The holographic correspondence (which is different than Strominger's de Sitter (dS)\\/CFT duality) relates the decay of (3+1)-dimensional de Sitter space to a two-dimensional CFT. It is not associated with pure de Sitter space,

Ben Freivogel; Yasuhiro Sekino; Leonard Susskind; Chen-Pin Yeh

2006-01-01

228

Induction of morphological changes in death-induced cancer cells monitored by holographic microscopy.  

PubMed

We are using the label-free technique of holographic microscopy to analyze cellular parameters including cell number, confluence, cellular volume and area directly in the cell culture environment. We show that death-induced cells can be distinguished from untreated counterparts by the use of holographic microscopy, and we demonstrate its capability for cell death assessment. Morphological analysis of two representative cell lines (L929 and DU145) was performed in the culture flasks without any prior cell detachment. The two cell lines were treated with the anti-tumour agent etoposide for 1-3days. Measurements by holographic microscopy showed significant differences in average cell number, confluence, volume and area when comparing etoposide-treated with untreated cells. The cell volume of the treated cell lines was initially increased at early time-points. By time, cells decreased in volume, especially when treated with high doses of etoposide. In conclusion, we have shown that holographic microscopy allows label-free and completely non-invasive morphological measurements of cell growth, viability and death. Future applications could include real-time monitoring of these holographic microscopy parameters in cells in response to clinically relevant compounds. PMID:25637284

El-Schich, Zahra; Mölder, Anna; Tassidis, Helena; Härkönen, Pirkko; Falck Miniotis, Maria; Gjörloff Wingren, Anette

2015-03-01

229

Volume flow calculations on gas leaks imaged with infrared gas-correlation.  

PubMed

Two methods for volume flow calculation from images of methane leakages to the atmosphere are presented. The images contain calibrated gas concentration × path length pixel information, and are processed with a block matching method and a theoretical velocity field method. Results from known methane flow in two laboratory setups and one unknown real leakage from a gas processing plant are compared with the image processing methods. The methods are generic and can be implemented in common infrared systems for gas visualization. This work provides a new tool for estimating and reporting volume flow emissions from gas processing plants to the authorities. PMID:23037083

Sandsten, Jonas; Andersson, Martin

2012-08-27

230

Inhomogeneous holographic thermalization  

NASA Astrophysics Data System (ADS)

The sudden injection of energy in a strongly coupled conformal field theory and its subsequent thermalization can be holographically modeled by a shell falling into anti-de Sitter space and forming a black brane. For a homogeneous shell, Bhattacharyya and Minwalla were able to study this process analytically using a weak field approximation. Motivated by event-by-event fluctuations in heavy ion collisions, we include inhomogeneities in this model, obtaining analytic results in a long wavelength expansion. In the early-time window in which our approximations can be trusted, the resulting evolution matches well with that of a simple free streaming model. Near the end of this time window, we find that the stress tensor approaches that of second-order viscous hydrodynamics. We comment on possible lessons for heavy ion phenomenology.

Balasubramanian, V.; Bernamonti, A.; de Boer, J.; Craps, B.; Franti, L.; Galli, F.; Keski-Vakkuri, E.; Müller, B.; Schäfer, A.

2013-10-01

231

A Rotating Holographic Superconductor  

E-print Network

In this paper we initiate the study of SSB in 3+1 dimensional rotating, charged, asymptotically AdS black holes. The theory living on their boundary, R x S^2, has the interpretation of a 2+1 dimensional rotating holographic superconductor. We study the appearance of a marginal mode of the condensate as the temperature is decreased. We find that the transition temperature depends on the rotation. At temperatures just below T_c, the transition temperature at zero rotation, there exists a critical value of the rotation, which destroys the superconducting order. This behaviour is analogous to the emergence of a critical applied magnetic field and we show that the superconductor in fact produces the expected London field in the planar limit.

Julian Sonner

2009-03-31

232

Holographic Recording Materials Development  

NASA Technical Reports Server (NTRS)

Organic photorefractive materials were evaluated for application in a reversible holographic memory system. Representative indigo and thioindigo derivatives and several stilbene derivatives were studied as well as 15, 16-dialkyldihydropyrene derivatives the following goals were achieved: (1) the successful writing of phase holograms in a thioindigo/polymer gel system, (2) the successful writing and erasing of phase holograms in a variety of indigo/polymer gel and indigo/solid polymer systems, and (3) the identification of indigoid dyes and 15, 16-dialkyldihydropyrene derivatives as materials potentially suitable for utilization in an operational system. Photochemical studies of the stilbene, indigo, thioindigo, and dialkyldihydropyrene derivatives in solution and in a variety of polymer matrix materials were conducted with the goal of optimizing the photorefractive behavior of the chemical system as a whole. The spectroscopic properties required of optimal photorefractive materials were identified, and it was shown that both the indigoid dyes and the dialkyldihydropyrenes closely match the required properties.

Verber, C. M.; Schwerzel, R. E.; Perry, P. J.; Craig, R. A.

1976-01-01

233

Stability of holographic superconductors  

SciTech Connect

We study the dynamical stability of holographic superconductors. We first classify perturbations around black hole background solutions into vector and scalar sectors by means of a 2-dimensional rotational symmetry. We prove the stability of the vector sector by explicitly constructing the positive definite Hamiltonian. To reveal a mechanism for the stabilization of a superconducting phase, we construct a quadratic action for the scalar sector. From the action, we see the stability of black holes near a critical point is determined by the equation of motion for a charged scalar field. We show the effective mass of the charged scalar field in hairy black holes is always above the Breitenlohner-Freedman bound near the critical point due to the backreaction of a gauge field. It implies the stability of the superconducting phase. We also argue that the stability continues away from the critical point.

Kanno, Sugumi [Centre for Particle Theory, Department of Mathematical Sciences, Durham University, Science Laboratories, South Road, Durham, DH1 3LE (United Kingdom); Soda, Jiro [Department of Physics, Kyoto University, Kyoto, 606-8501 (Japan)

2010-10-15

234

Holographic Vortex Coronagraph  

NASA Technical Reports Server (NTRS)

A holographic vortex coronagraph (HVC) has been proposed as an improvement over conventional coronagraphs for use in high-contrast astronomical imaging for detecting planets, dust disks, and other broadband light scatterers in the vicinities of stars other than the Sun. Because such light scatterers are so faint relative to their parent stars, in order to be able to detect them, it is necessary to effect ultra-high-contrast (typically by a factor of the order of 1010) suppression of broadband light from the stars. Unfortunately, the performances of conventional coronagraphs are limited by low throughput, dispersion, and difficulty of satisfying challenging manufacturing requirements. The HVC concept offers the potential to overcome these limitations.

Palacios, David

2010-01-01

235

Rotating holographic superconductor  

SciTech Connect

In this paper we initiate the study of spontaneous symmetry breaking in 3+1 dimensional rotating, charged, asymptotically AdS black holes. The theory living on their boundary, RxS{sup 2}, has the interpretation of a 2+1 dimensional rotating holographic superconductor. We study the appearance of a marginal mode of the condensate as the temperature is decreased. We find that the transition temperature depends on the rotation. At temperatures just below T{sub c}, the transition temperature at zero rotation, there exists a critical value of the rotation, which destroys the superconducting order. This behavior is analogous to the emergence of a critical applied magnetic field and we show that the superconductor in fact produces the expected London field in the planar limit.

Sonner, Julian [Blackett Laboratory, Imperial College, London, SW7 2AZ (United Kingdom) and Trinity College, University of Cambridge, Cambridge, CB2 1TQ (United Kingdom)

2009-10-15

236

Creatine Kinase Activity Weakly Correlates to Volume Completed Following Upper Body Resistance Exercise  

ERIC Educational Resources Information Center

In the current study, we examined the relationship between serum creatine kinase (CK) activity following upper body resistance exercise with a 1- or 3-min rest between sets. Twenty men performed two sessions, each consisting of four sets with a 10-repetition maximum load. The results demonstrated significantly greater volume for the 3-min…

Machado, Marco; Willardson, Jeffrey M.; Silva, Dailson P.; Frigulha, Italo C.; Koch, Alexander J.; Souza, Sergio C.

2012-01-01

237

Maternal Iodine Status and Thyroid Volume during Pregnancy: Correlation with Neonatal Iodine Intake  

Microsoft Academic Search

Differences in pregnancy-associated alterations in thyroid vol- ume and urinary iodine (UI) excretion have been attributed to geographical variations in dietary iodine intake. In this study, ultrasound-measured thyroid volume and UI excretion were as- sessed during the 3 trimesters of pregnancy, at delivery, and at 6 weeks postpartum. Urine specimens also were obtained from moth- ers and both breast- and

P. P. A. Smyth; A. M. T. HETHERTON; D. F. SMITH; M. RADCLIFF; C. O'HERLIHY

1997-01-01

238

Serotonergic, brain volume and attentional correlates of trait anxiety in primates  

E-print Network

throughout each region to measure regional volumes in each subject. Statistics Statistical analysis was performed in SPSS 22.0. The data were checked for normality and homoscedasticity, and one-sample t-tests, ANOVA with Sidak or Fisher’s LSD pair...

Mikheenko, Yevheniia; Shiba, Yoshiro; Sawiak, Stephen; Braesicke, Katrin; Cockcroft, Gemma; Clarke, Hannah; Roberts, Angela C.

2015-01-14

239

Relative Wulst volume is correlated with orbit orientation and binocular visual field in birds  

Microsoft Academic Search

In mammals, species with more frontally oriented orbits have broader binocular visual fields and relatively larger visual\\u000a regions in the brain. Here, we test whether a similar pattern of correlated evolution is present in birds. Using both conventional\\u000a statistics and modern comparative methods, we tested whether the relative size of the Wulst and optic tectum (TeO) were significantly\\u000a correlated with

Andrew N. Iwaniuk; Christopher P. Heesy; Margaret I. Hall; Douglas R. W. Wylie

2008-01-01

240

Local shear stress and its correlation with local volume fraction in concentrated non-Brownian suspensions: Lattice Boltzmann simulation  

NASA Astrophysics Data System (ADS)

The local shear stress of non-Brownian suspensions was investigated using the lattice Boltzmann method coupled with the smoothed profile method. Previous studies have only focused on the bulk rheology of complex fluids because the local rheology of complex fluids was not accessible due to technical limitations. In this study, the local shear stress of two-dimensional solid particle suspensions in Couette flow was investigated with the method of planes to correlate non-Newtonian fluid behavior with the structural evolution of concentrated particle suspensions. Shear thickening was successfully captured for highly concentrated suspensions at high particle Reynolds number, and both the local rheology and local structure of the suspensions were analyzed. It was also found that the linear correlation between the local particle stress and local particle volume fraction was dramatically reduced during shear thickening. These results clearly show how the change in local structure of suspensions influences the local and bulk rheology of the suspensions.

Lee, Young Ki; Ahn, Kyung Hyun; Lee, Seung Jong

2014-12-01

241

Local shear stress and its correlation with local volume fraction in concentrated non-Brownian suspensions: lattice Boltzmann simulation.  

PubMed

The local shear stress of non-Brownian suspensions was investigated using the lattice Boltzmann method coupled with the smoothed profile method. Previous studies have only focused on the bulk rheology of complex fluids because the local rheology of complex fluids was not accessible due to technical limitations. In this study, the local shear stress of two-dimensional solid particle suspensions in Couette flow was investigated with the method of planes to correlate non-Newtonian fluid behavior with the structural evolution of concentrated particle suspensions. Shear thickening was successfully captured for highly concentrated suspensions at high particle Reynolds number, and both the local rheology and local structure of the suspensions were analyzed. It was also found that the linear correlation between the local particle stress and local particle volume fraction was dramatically reduced during shear thickening. These results clearly show how the change in local structure of suspensions influences the local and bulk rheology of the suspensions. PMID:25615103

Lee, Young Ki; Ahn, Kyung Hyun; Lee, Seung Jong

2014-12-01

242

3D holographic printer: fast printing approach.  

PubMed

This article describes the general operation principles of devices for synthesized holographic images such as holographic printers. Special emphasis is placed on the printing speed. In addition, various methods to increase the printing process are described and compared. PMID:24663511

Morozov, Alexander V; Putilin, Andrey N; Kopenkin, Sergey S; Borodin, Yuriy P; Druzhin, Vladislav V; Dubynin, Sergey E; Dubinin, German B

2014-02-10

243

Depolarization volume and correlation length in the homogenization of anisotropic dielectric composites  

Microsoft Academic Search

In conventional approaches to the homogenization of random particulate\\u000acomposites, both the distribution and size of the component phase particles are\\u000aoften inadequately taken into account. Commonly, the spatial distributions are\\u000acharacterized by volume fraction alone, while the electromagnetic response of\\u000aeach component particle is represented as a vanishingly small depolarization\\u000avolume. The strong-permittivity-fluctuation theory (SPFT) provides an\\u000aalternative approach

Tom G. Mackay; James Clerk

2004-01-01

244

Cerebral blood volume in Alzheimer's disease and correlation with tissue structural integrity  

Microsoft Academic Search

A vascular component is increasingly recognized as important in Alzheimer's disease (AD). We measured cerebral blood volume (CBV) in patients with probable AD or Mild Cognitive Impairment (MCI) and in elderly non-demented subjects using a recently developed Vascular-Space-Occupancy (VASO) MRI technique. While both gray and white matters were examined, significant CBV deficit regions were primarily located in white matter, specifically

Jinsoo Uh; Kelly Lewis-Amezcua; Kristin Martin-Cook; Yamei Cheng; Myron Weiner; Ramon Diaz-Arrastia; Michael Devous Sr.; Dinggang Shen; Hanzhang Lu

2010-01-01

245

Significant correlations between the flow volume of patent ductus venosus and early neonatal liver function: possible involvement of patent ductus venosus in postnatal liver function  

PubMed Central

Background The biochemical features of portosystemic venous shunt with high flow volume are hypergalactosaemia, hyperammonaemia, prolonged blood coagulation time, and raised serum bile acid concentration. The ductus venosus remains open with shunt flow in most neonates for a certain period after birth. However, the effects of blood flow through the ductus venosus on neonatal liver function remain unclear. Objective To elucidate the effect of patency of the ductus venosus on liver function in early neonates. Methods Subjects were divided into three groups by gestational age (group I, 29–32?weeks; group II, 33–36?weeks; group III, 37–41?weeks). The shunt flow volume through the ductus venosus was examined serially using ultrasonography, and correlations between flow volume and liver function in the respective groups were calculated during the first week after birth. Results Group I had a higher flow volume and later functional closure than the other two groups. Plasma ammonia and serum total bile acid concentrations correlated with flow volume in groups I and II, and blood galactose and galactose 1?phosphate concentrations correlated significantly with flow volume in group III. Percentage hepaplastin also correlated significantly with flow volume in all groups, but plasma vitamin K concentration did not in any group. Conclusions Patent ductus venosus has a considerable effect on crucial liver functions such as ammonia detoxification, blood coagulation, and regulation of serum total bile acid concentration in early neonates. PMID:16449256

Murayama, K; Nagasaka, H; Tate, K; Ohsone, Y; Kanazawa, M; Kobayashi, K; Kohno, Y; Takayanagi, M

2006-01-01

246

Holographic Aspects of Electric-Magnetic Dualities  

E-print Network

We review recent work on holographic aspects of electric-magnetic dualities in theories that involve conformally coupled scalars and abelian gauge fields in asymptotically AdS4 spaces. Such models are relevant for the holographic description of M-theory. We also briefly comment on some new results on the holographic properties of generalized electric-magnetic duality in gravity.

Sebastian de Haro; Anastasios C. Petkou

2007-10-04

247

Holographic optical elements: Fabrication and testing  

NASA Technical Reports Server (NTRS)

The basic properties and use of holographic optical elements were investigated to design and construct wide-angle, Fourier-transform holographic optical systems for use in a Bragg-effect optical memory. The performance characteristics are described along with the construction of the holographic system.

Zech, R. G.; Shareck, M.; Ralston, L. M.

1974-01-01

248

Correlation  

NSDL National Science Digital Library

Three hypothetical rock sections along an East-West transect are provided. Students correlate the three sections using the biostratigraphy of planktic forams (as a proxy for age), benthic forams (as a proxy of depth), and lithology (as a proxy of environment). Students are asked to provide an interpretation of the history of this depositional basin. An ash bed of known age is added and students are asked to determine if this new information affects their interpretation. Finally, an interesting lithologic feature is added, and students are asked to provide a geological explanation.

Pennilyn Higgins

249

The cosmic X-ray background-IRAS galaxy correlation and the local X-ray volume emissivity  

NASA Technical Reports Server (NTRS)

We have cross-correlated the galaxies from the IRAS 2 Jy redshift survey sample and the 0.7 Jy projected sample with the all-sky cosmic X-ray background (CXB) map obtained from the High Energy Astronomy Observatory (HEAO) 1 A-2 experiment. We have detected a significant correlation signal between surface density of IRAS galaxies and the X-ray background intensity, with W(sub xg) = (mean value of ((delta I)(delta N)))/(mean value of I)(mean value of N)) of several times 10(exp -3). While this correlation signal has a significant implication for the contribution of the local universe to the hard (E greater than 2 keV) X-ray background, its interpretation is model-dependent. We have developed a formulation to model the cross-correlation between CXB surface brightness and galaxy counts. This includes the effects of source clustering and the X-ray-far-infrared luminosity correlation. Using an X-ray flux-limited sample of active galactic nuclei (AGNs), which has IRAS 60 micrometer measurements, we have estimated the contribution of the AGN component to the observed CXB-IRAS galaxy count correlations in order to see whether there is an excess component, i.e., contribution from low X-ray luminosity sources. We have applied both the analytical approach and Monte Carlo simulations for the estimations. Our estimate of the local X-ray volume emissivity in the 2-10 keV band is rho(sub x) approximately = (4.3 +/- 1.2) x 10(exp 38) h(sub 50) ergs/s/cu Mpc, consistent with the value expected from the luminosity function of AGNs alone. This sets a limit to the local volume emissivity from lower luminosity sources (e.g., star-forming galaxies, low-ionization nuclear emission-line regions (LINERs)) to rho(sub x) less than or approximately = 2 x 10(exp 38) h(sub 50) ergs/s/cu Mpc.

Miyaji, Takamitsu; Lahav, Ofer; Jahoda, Keith; Boldt, Elihu

1994-01-01

250

Right Anterior Cingulate Cortical Thickness and Bilateral Striatal Volume Correlate with CBCL Aggressive Behavior Scores in Healthy Children  

PubMed Central

Background The anterior cingulate cortex (ACC), orbito-frontal cortex (OFC) and basal ganglia have been implicated in pathological aggression. This study aimed at identifying neuroanatomical correlates of impulsive aggression in healthy children. Methods Data from 193 representative 6–18 year-old healthy children were obtained from the NIH MRI Study of Normal Brain Development after a blinded quality control (1). Cortical thickness and subcortical volumes were obtained with automated software. Aggression levels were measured with the Aggressive Behavior scale (AGG) of the Child Behavior Checklist (CBCL). AGG scores were regressed against cortical thickness and basal ganglia volumes using first and second-order linear models while controlling for age, gender, scanner site and total brain volume. ‘Gender by AGG’ interactions were analyzed. Results There were positive associations between bilateral striatal volumes and AGG scores (right: r=0.238, p=0.001; left: r=0.188, p=0.01). A significant association was found with right ACC and subgenual ACC cortical thickness in a second-order linear model (p<0.05, corrected). High AGG scores were associated with a relatively thin right ACC cortex. An ‘AGG by gender’ interaction trend was found in bilateral OFC and ACC associations with AGG scores. Conclusion This study shows the existence of relationships between impulsive aggression in healthy children and the structure of the striatum and right ACC. It also suggests the existence of gender specific patterns of association in OFC/ACC grey matter. These results may guide research on oppositional-defiant and conduct disorders. PMID:21531391

Ducharme, Simon; Hudziak, James J; Botteron, Kelly N; Ganjavi, Hooman; Lepage, Claude; Collins, D Louis; Albaugh, Matthew D.; Evans, Alan C; Karama, Sherif

2011-01-01

251

Holographic framework for eternal inflation  

NASA Astrophysics Data System (ADS)

In this paper we provide some circumstantial evidence for a holographic duality between bubble nucleation in an eternally inflating universe and a Euclidean conformal field theory (CFT). The holographic correspondence (which is different than Strominger’s de Sitter (dS)/CFT duality) relates the decay of (3+1)-dimensional de Sitter space to a two-dimensional CFT. It is not associated with pure de Sitter space, but rather with Coleman-De Luccia bubble nucleation. Alternatively, it can be thought of as a holographic description of the open, infinite, Friedmann-Robertson-Walker (FRW) cosmology that results from such a bubble. The conjectured holographic representation is of a new type that combines holography with the Wheeler-DeWitt formalism to produce a Wheeler-DeWitt theory that lives on the spatial boundary of a k=-1 FRW cosmology. We also argue for a more ambitious interpretation of the Wheeler-DeWitt CFT as a holographic dual of the entire Landscape.

Freivogel, Ben; Sekino, Yasuhiro; Susskind, Leonard; Yeh, Chen-Pin

2006-10-01

252

Holographic framework for eternal inflation  

SciTech Connect

In this paper we provide some circumstantial evidence for a holographic duality between bubble nucleation in an eternally inflating universe and a Euclidean conformal field theory (CFT). The holographic correspondence (which is different than Strominger's de Sitter (dS)/CFT duality) relates the decay of (3+1)-dimensional de Sitter space to a two-dimensional CFT. It is not associated with pure de Sitter space, but rather with Coleman-De Luccia bubble nucleation. Alternatively, it can be thought of as a holographic description of the open, infinite, Friedmann-Robertson-Walker (FRW) cosmology that results from such a bubble. The conjectured holographic representation is of a new type that combines holography with the Wheeler-DeWitt formalism to produce a Wheeler-DeWitt theory that lives on the spatial boundary of a k=-1 FRW cosmology. We also argue for a more ambitious interpretation of the Wheeler-DeWitt CFT as a holographic dual of the entire Landscape.

Freivogel, Ben [Center for Theoretical Physics, Department of Physics, University of California, Berkeley, California (United States); Lawrence Berkeley National Laboratory, Berkeley, California (United States); Sekino, Yasuhiro [Department of Physics, Stanford University, Stanford, California (United States); Okayama Institute for Quantum Physics, 1-9-1 Kyoyama, Okayama 700-0015 (Japan); Susskind, Leonard; Yeh, Chen-Pin [Department of Physics, Stanford University, Stanford, California (United States)

2006-10-15

253

Tumor Volume Reduction Rate Measured by Magnetic Resonance Volumetry Correlated With Pathologic Tumor Response of Preoperative Chemoradiotherapy for Rectal Cancer  

SciTech Connect

Purpose: To determine whether the tumor volume reduction rate (TVRR) measured using three-dimensional region-of-interest magnetic resonance volumetry correlates with the pathologic tumor response after preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer. Methods and Materials: The study included 405 patients with locally advanced rectal cancer (cT3-T4) who had undergone preoperative CRT and radical proctectomy. The tumor volume was measured using three-dimensional region-of-interest magnetic resonance volumetry before and after CRT but before surgery. We analyzed the correlation between the TVRR and the pathologic tumor response in terms of downstaging and tumor regression grade (TRG). Downstaging was defined as ypStage 0-I (ypT0-T2N0M0), and the TRG proposed by Dworak et al. was used. Results: The mean TVRR was 65.0% {+-} 22.3%. Downstaging and complete regression occurred in 167 (41.2%) and 58 (14.3%) patients, respectively. The TVRRs according to ypT classification (ypT0-T2 vs. ypT3-T4), ypN classification (ypN0 vs. ypN1-N2), downstaging (ypStage 0-I vs. ypStage II-III), good regression (TRG 3-4 vs. TRG 1-2), and complete regression (TRG 4 vs. TRG 1-3) were all significantly different (p <.05). When the TVRR was categorized into three groups (<60%, 60-80%, and >80%), the rates of ypT0-T2, ypN0, downstaging, and good regression were all significantly greater for patients with a TVRR of {>=}60%, as was the complete regression rate for patients with a TVRR >80% (p <.05). Conclusion: The TVRR measured using three-dimensional region-of-interest magnetic resonance volumetry correlated significantly with the pathologic tumor response in terms of downstaging and TRG after preoperative CRT for locally advanced rectal cancer.

Yeo, Seung-Gu [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Department of Radiation Oncology, Soon Chun Hyang University College of Medicine, Cheonan (Korea, Republic of); Kim, Dae Yong, E-mail: radiopiakim@hanmail.ne [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Kim, Tae Hyun [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Jung, Kyung Hae; Hong, Yong Sang [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Department of Medical Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Chang, Hee Jin; Park, Ji Won [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Lim, Seok-Byung [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Department of Colon and Rectal Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Choi, Hyo Seong [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Jeong, Seung-Yong [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang (Korea, Republic of); Department of Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of)

2010-09-01

254

Holographic Adaptive Optics  

NASA Astrophysics Data System (ADS)

For the last two decades adaptive optics has been used as a technique for correcting imaging applications and directed energy/laser targeting and laser communications systems affected by atmospheric turbulence. Typically these systems are bulky and limited to <10 kHz due to large computing overhead and limited photon efficiencies. Moreover most use zonal wavefront sensors which cannot easily handle extreme scintillation or unexpected obscuration of a pre-set aperture. Here we present a compact, lightweight adaptive optics system with the potential to operate at speeds of MHz. The system utilizes a hologram to perform an all-optical wavefront analysis that removes the need for any computer. Finally, the sensing is made on a modal basis so it is largely insensitive to scintillation and obscuration. We have constructed a prototype device and will present experimental results from our research. The holographic adaptive optics system begins with the creation of a multiplexed hologram. This hologram is created by recording the maximum and minimum response functions of every actuator in the deformable mirror against a unique focused reference beam. When a wavefront of some arbitrary phase is incident on the processed hologram, a number of focal spots are created -- one pair for each actuator in the DM. The absolute phase error at each particular actuator location is simply related to the ratio of the intensity of each pair of spots. In this way we can use an array of photodetectors to give a direct readout of phase error without the need for any calculations. The advantages of holographic adaptive optics are many. To begin with, the measurement of phase error is made all optically, so the wavefront sensor directly controls the actuators in the DM without any computers. Using fast, photon counting photodetectors allows for closed loop correction limited only by the speed of the deformable mirror which in the case of MEMS devices can be 100 kHz or more. All this can be achieved in an extremely compact and lightweight package making it perfectly suited to applications such as UAV surveillance imagery and free space optical communications systems. Lastly, since the correction is made on a modal basis instead of zonal, it is virtually insensitive to scintillation and obscuration.

Andersen, G.

255

Nonvolatile Rad-Hard Holographic Memory  

NASA Technical Reports Server (NTRS)

We are investigating a nonvolatile radiation-hardened (rad-hard) holographic memory technology. Recently, a compact holographic data storage (CHDS) breadboard utilizing an innovative electro-optic scanner has been built and demonstrated for high-speed holographic data storage and retrieval. The successful integration of this holographic memory breadboard has paved the way for follow-on radiation resistance test of the photorefractive (PR) crystal, Fe:LiNbO3. We have also started the investigation of using two-photon PR crystals that are doubly doped with atoms of iron group (Ti, Cr, Mn, Cu) and of rare-earth group (Nd, Tb) for nonvolatile holographic recordings.

Chao, Tien-Hsin; Zhou, Han-Ying; Reyes, George; Dragoi, Danut; Hanna, Jay

2001-01-01

256

Chiral Ground States in a Frustrated Holographic Superconductor  

E-print Network

Frustration is an important phenomenon in condensed matter physics because it can introduce a new order parameter such as chirality. Towards understanding a mechanism of the frustration in strongly correlated systems, we study a holographic superconductor model with three scalar fields and an interband Josephson coupling, which is important for the frustration. We analyze free energy of solutions of the model to determine ground states. We find chiral ground states, which have nonzero chirality.

Mitsuhiro Nishida

2015-02-28

257

Chiral Ground States in a Frustrated Holographic Superconductor  

E-print Network

Frustration is an important phenomenon in condensed matter physics because it can introduce a new order parameter such as chirality. Towards understanding a mechanism of the frustration in strongly correlated systems, we study a holographic superconductor model with three scalar fields and an interband Josephson coupling, which is important for the frustration. We analyze free energy of solutions of the model to determine ground states. We find chiral ground states, which have nonzero chirality.

Nishida, Mitsuhiro

2015-01-01

258

3D deformation and strain analysis in compacted sugar using x-ray microtomography and digital volume correlation  

NASA Astrophysics Data System (ADS)

Understanding the displacement of granular beds under compaction is important for a range of industrial, geological and civil engineering applications. Such materials exhibit inhomogeneous internal displacements including strain localization, which mean that a method for the in situ evaluation of internal 3D displacement fields at high spatial resolutions would be a major development. This paper presents results from the compaction of a cylindrical bed of sugar, with diameter 7.0 mm and height 8.2 mm, using x-ray microtomography to evaluate the internal structure and digital volume correlation to calculate 3D displacement information from these data. In contrast to previous studies, which generally track a small number of marker particles, the research here uses the natural structure of the sugar to provide a random pattern for 3D image correlation, allowing full-field information to be captured. The results show good agreement when compared with a well-established 2D image correlation technique; moreover, they indicate structural features associated with deformation of granular materials that would not necessarily be observed in a 2D slice.

Forsberg, F.; Siviour, C. R.

2009-09-01

259

Pollen size evolution: correlation between pollen volume and pistil length in Asteraceae  

Microsoft Academic Search

Based on the assumptions that pollen tube length is predetermined by provisions in the pollen and that it is a function of\\u000a pistil length, I hypothesise that species with longer pistils will have larger pollen grains than species with shorter pistils,\\u000a and that pistil length and pollen size will be positively correlated in a linear manner. To test this hypothesis,

Carolina Torres

2000-01-01

260

Holographic films from carotenoid pigments  

NASA Astrophysics Data System (ADS)

Carotenoids pigments presents in pineapple can be more than just natural dyes, which is one of the applications that now at day gives the chemical industry. In this research shown that can be used in implementing of holographic recording Films. Therefore we describe the technique how to obtain this kind of pigments trough spay drying of natural pineapple juice, which are then dissolved with water in a proportion of 0.1g to 1mL. The obtained sample is poured into glass substrates using the gravity method, after a drying of 24 hours in laboratory normal conditions the films are ready. The films are characterized by recording transmission holographic gratings (LSR 445 NL 445 nm) and measuring the diffraction efficiency holographic parameter. This recording material has good diffraction efficiency and environmental stability.

Toxqui-López, S.; Lecona-Sánchez, J. F.; Santacruz-Vázquez, C.; Olivares-Pérez, A.; Fuentes-Tapia, I.

2014-02-01

261

Hard-gapped Holographic Superconductors  

E-print Network

In this work we discuss the zero temperature limit of a "p-wave" holographic superconductor. The bulk description consists of a non-Abelian SU(2) gauge fields minimally coupled to gravity. We numerically construct the zero temperature solution which is the gravity dual of the superconducting ground state of the "p-wave" holographic superconductors. The solution is a smooth soliton with zero horizon size and shows an emergent conformal symmetry in the IR. We found the expected superconducting behavior. Using the near horizon analysis we show that the system has a "hard gap" for the relevant gauge field fluctuations. At zero temperature the real part of the conductivity is zero for an excitation frequency less than the gap frequency. This is in contrast with what has been observed in similar scalar- gravity-gauge systems (holographic superconductors). We also discuss the low but finite temperature behavior of our solution.

Pallab Basu; Jianyang He; Anindya Mukherjee; Hsien-Hang Shieh

2009-12-05

262

Holographic indeterminacy and neutron stars  

E-print Network

The holographic indeterminacy resulting from the quantization of spacetime leads to an inherent uncertainty (lpL)1/2 in the relative positions of two events, separated by a distance L, in a direction transverse to a null ray connecting the events, where lP is the Planck length. The new indeterminacy principle leads to a critical condition in which the holographic uncertainty in the relative transverse positions of two diametrically opposed particles on the surface a body becomes greater than the average distance between particles in the body. The Chandrasekhar mass and the characteristic nuclear density emerge as the minimum mass and density of a baryonic body that could meet the critical criteria. Neutron stars are therefore identified as a class of bodies in which holographic indeterminacy may have physical consequences.

Scott Funkhouser

2009-02-16

263

Universality in holographic entropy production  

E-print Network

We consider the time evolution of two entropy-like quantities, the holographic entanglement entropy and causal holographic information, in a model of holographic thermalization dual to the gravitational collapse of a thin planar shell. Unlike earlier calculations valid in different limits, we perform a full treatment of the dynamics of the system, varying both the shell's equation of state and initial position. In all cases considered, we find that between an early period related to the acceleration of the shell and a late epoch of saturation towards the thermal limit, the entanglement entropy exhibits universal linear growth in time in accordance with the prediction of Liu and Suh. As intermediate steps of our analysis, we explicitly construct a coordinate system continuous at the location of an infinitely thin shell and derive matching conditions for geodesics and extremal surfaces traversing this region.

Ville Keranen; Hiromichi Nishimura; Stefan Stricker; Olli Taanila; Aleksi Vuorinen

2014-06-04

264

Holographic holes in higher dimensions  

NASA Astrophysics Data System (ADS)

We extend the holographic construction of [1] from AdS3 to higher dimensions. In particular, we show that the Bekenstein-Hawking entropy of codimension-two surfaces in the bulk with planar symmetry can be evaluated in terms of the `differential entropy' in the boundary theory. The differential entropy is a certain quantity constructed from the entanglement entropies associated with a family of regions covering a Cauchy surface in the boundary geometry. We demonstrate that a similar construction based on causal holographic information fails in higher dimensions, as it typically yields divergent results. We also show that our construction extends to holographic backgrounds other than AdS spacetime and can accommodate Lovelock theories of higher curvature gravity.

Myers, Robert C.; Rao, Junjie; Sugishita, Sotaro

2014-06-01

265

A supersymmetric holographic dual of a fractional topological insulator  

E-print Network

We construct a supersymmetric generalization of the holographic dual of a fractional topological insulator found in \\cite{HoyosBadajoz:2010ac}. This is accomplished by introducing a nontrivial gauge field on the world volume of the probe D7 brane. The BPS equations are derived from the $\\kappa$-symmetry transformation of the probe brane. The BPS equations are shown to reduce to two first oder nonlinear partial differential equations. Solutions of the BPS equations correspond to a probe brane configuration which preserves four of the thirty-two supersymmetries of the $AdS_5\\times S^5$ background. Solutions of the BPS equations which correspond to a holographic fractional topological insulator are obtained numerically.

Martin Ammon; Michael Gutperle

2012-04-10

266

Polymer electrolyte membranes with exceptional conductivity anisotropy via holographic polymerization  

NASA Astrophysics Data System (ADS)

Polymer electrolyte membranes using an ionic liquid as electrolyte with an ionic conductivity anisotropy of ?5000 have been fabricated using a holographic polymerization nanomanufacturing technique. The resultant structure is referred to as holographic polymer electrolyte membranes (hPEMs), which are comprised of alternating nanolayers of a room temperature ionic liquid and crosslinked polymer resin, confirmed under TEM imaging. These hPEMs also show no reduction in room temperature conductivity with respect to the loaded ionic liquid when characterized in the plane of ionic liquid nanolayers. At elevated temperatures with the optimal electrolyte volume loading, calculation shows that the free ion concentration is higher than the pure ionic liquid, suggesting that the photopolymer dual-functionalizes as a loadbearing scaffold and an ion-complexing agent, allowing for more ions to participate in charge transfer. These hPEMs provide a promising solution to decoupling mechanical enhancement and ion transport in polymer electrolyte membranes.

Smith, Derrick M.; Cheng, Shan; Wang, Wenda; Bunning, Timothy J.; Li, Christopher Y.

2014-12-01

267

Advances with holographic DESA emulsions  

NASA Astrophysics Data System (ADS)

DESA emulsions represent layer systems based on ultra-fine grained silver halide (AgX) technology. The new layers have an excellent performance for holographic application. The technology has been presented repeatedly in recent years, including the emulsion characterization and topics of chemical and spectral sensitization. The paper gives a survey of actual results referring to panchromatic sensitization and other improvements like the application of silver halide sensitized gelatine (SHSG) procedure. These results are embedded into intensive collaborations with small and medium enterprises (SME's) to commercialize DESA layers. Predominant goals are innovative products with holographic components and layers providing as well as cost effectiveness and high quality.

Dünkel, Lothar; Eichler, Jürgen; Schneeweiss, Claudia; Ackermann, Gerhard

2006-02-01

268

Holographic Chern–Simons Theories  

NASA Astrophysics Data System (ADS)

Chern-Simons theories in three dimensions are topological field theories that may have a holographic interpretation for suitable chosen gauge groups and boundary conditions on the fields. Conformal Chern-Simons gravity is a topological model of three-dimensional gravity that exhibits Weyl invariance and allows various holographic descriptions, including Anti-de Sitter, Lobachevsky and flat space holography. The same model also allows to address some aspects that arise in higher spin gravity in a considerably simplified setup, since both types of models have gauge symmetries other than diffeomorphisms. In these lectures we summarize briefly recent results.

Afshar, H.; Bagchi, A.; Detournay, S.; Grumiller, D.; Prohazka, S.; Riegler, M.

269

Go with the Flow, Average Holographic Universe  

E-print Network

Gravity is a macroscopic manifestation of a microscopic quantum theory of space-time, just as the theories of elasticity and hydrodynamics are the macroscopic manifestation of the underlying quantum theory of atoms. The connection of gravitation and thermodynamics is long and deep. The observation that space-time has a temperature for accelerating observers and horizons is direct evidence that there are underlying microscopic degrees of freedom. The equipartition of energy, meaning of temperature, in these modes leads one to anticipate that there is also an entropy associated. When this entropy is maximized on a volume of space-time, then one retrieves the metric of space-time (i.e. the equations of gravity, e.g. GR). Since the metric satisfies the extremum in entropy on the volume, then the volume integral of the entropy can readily be converted to surface integral, via Gauss's Theorem. This surface integral is simply an integral of the macroscopic entropy flow producing the mean entropy holographic principle. This approach also has the added value that it naturally dispenses with the cosmological constant/vacuum energy problem in gravity except perhaps for second order quantum effects on the mean surface entropy.

George F. Smoot

2010-03-31

270

Cerebellar gray matter and lobular volumes correlate with core autism symptoms  

PubMed Central

Neuroanatomical differences in the cerebellum are among the most consistent findings in autism spectrum disorder (ASD), but little is known about the relationship between cerebellar dysfunction and core ASD symptoms. The newly-emerging existence of cerebellar sensorimotor and cognitive subregions provides a new framework for interpreting the functional significance of cerebellar findings in ASD. Here we use two complementary analyses — whole-brain voxel-based morphometry (VBM) and the SUIT cerebellar atlas — to investigate cerebellar regional gray matter (GM) and volumetric lobular measurements in 35 children with ASD and 35 typically-developing (TD) children (mean age 10.4 ± 1.6 years; range 8–13 years). To examine the relationships between cerebellar structure and core ASD symptoms, correlations were calculated between scores on the Autism Diagnostic Observation Schedule (ADOS) and Autism Diagnostic Interview (ADI) and the VBM and volumetric data. Both VBM and the SUIT analyses revealed reduced GM in ASD children in cerebellar lobule VII (Crus I/II). The degree of regional and lobular gray matter reductions in different cerebellar subregions correlated with the severity of symptoms in social interaction, communication, and repetitive behaviors. Structural differences and behavioral correlations converged on right cerebellar Crus I/II, a region which shows structural and functional connectivity with fronto-parietal and default mode networks. These results emphasize the importance of the location within the cerebellum to the potential functional impact of structural differences in ASD, and suggest that GM differences in cerebellar right Crus I/II are associated with the core ASD profile. PMID:25844317

D'Mello, Anila M.; Crocetti, Deana; Mostofsky, Stewart H.; Stoodley, Catherine J.

2015-01-01

271

Multilayered poly(vinylidene fluoride) composite membranes with improved interfacial compatibility: correlating pervaporation performance with free volume properties.  

PubMed

A spin-coating process integrated with an ozone-induced graft polymerization technique was applied in this study. The purpose was to improve the poor interfacial compatibility between a selective layer of poly(2-hydroxyethyl methacrylate) (PHEMA) and the surface of a poly(vinylidene fluoride) (PVDF) substrate. The composite membranes thus fabricated were tested for their pervaporation performance in dehydrating an ethyl acetate/water mixture. Furthermore, the composite membranes were characterized by field emission scanning electron microscopy (FE-SEM) for morphological change observation and by Fourier transform infrared spectroscopy equipped with attenuated total reflectance (ATR-FTIR) for surface chemical composition analysis. Effects of grafting density and spin-coating speed on pervaporation performance were examined. The composite membrane pervaporation performance was elucidated by means of free volume and depth profile data obtained with the use of a variable monoenergy slow positron beam (VMSPB). Results indicated that a smaller free volume was correlated with a higher pervaporation performance of a composite membrane consisting of a selective layer of spin-coated PHEMA on a PHEMA-grafted PVDF substrate (S-PHEMA/PHEMA-g-PVDF). The composite membrane depth profile illustrated that an S-PHEMA layer spin-coated at a higher revolutions per minute (rpm) was thinner and denser than that at a lower rpm. PMID:21740064

An, Quanfu; Chen, Jung-Tsai; De Guzman, Manuel; Hung, Wei-Song; Lee, Kueir-Rarn; Lai, Juin-Yih

2011-09-01

272

Universal properties of cold holographic matter  

E-print Network

We study the collective excitations of holographic quantum liquids formed in the low energy theory living at the intersection of two sets of D-branes. The corresponding field theory dual is a supersymmetric Yang-Mills theory with massless matter hypermultiplets in the fundamental representation of the gauge group which generically live on a defect of the unflavored theory. Working in the quenched (probe) approximation, we focus on determining the universal properties of these systems. We analyze their thermodynamics, the speed of first sound, the diffusion constant, and the speed of zero sound. We study the influence of temperature, chemical potential, and magnetic field on these quantities, as well as on the corresponding collisionless/hydrodynamic crossover. We also generalize the alternative quantization for all conformally $AdS_4$ backgrounds and study the anyonic correlators.

Jokela, Niko

2015-01-01

273

Universal properties of cold holographic matter  

E-print Network

We study the collective excitations of holographic quantum liquids formed in the low energy theory living at the intersection of two sets of D-branes. The corresponding field theory dual is a supersymmetric Yang-Mills theory with massless matter hypermultiplets in the fundamental representation of the gauge group which generically live on a defect of the unflavored theory. Working in the quenched (probe) approximation, we focus on determining the universal properties of these systems. We analyze their thermodynamics, the speed of first sound, the diffusion constant, and the speed of zero sound. We study the influence of temperature, chemical potential, and magnetic field on these quantities, as well as on the corresponding collisionless/hydrodynamic crossover. We also generalize the alternative quantization for all conformally $AdS_4$ cases and study the anyonic correlators.

Niko Jokela; Alfonso V. Ramallo

2015-04-07

274

Correlation between brain volume change and T2 relaxation time induced by dehydration and rehydration: Implications for monitoring atrophy in clinical studies  

PubMed Central

Brain volume change measured from magnetic resonance imaging (MRI) provides a widely used and useful in vivo measure of irreversible tissue loss. These measurements, however, can be influenced by reversible factors such as shifts in brain water content. Given the strong effect of water on T2 relaxation, we investigated whether an estimate of T2 relaxation time would correlate with brain volume changes induced by physiologically manipulating hydration status. We used a clinically feasible estimate of T2 (“pseudo-T2”) computed from a dual turbo spin-echo MRI sequence and correlated pseudo-T2 changes to percent brain volume changes in 12 healthy subjects after dehydration overnight (16-hour thirsting) and rehydration (drinking 1.5 L of water). We found that the brain volume significantly increased between the dehydrated and rehydrated states (mean brain volume change = 0.36%, p = 0.0001) but did not change significantly during the dehydration interval (mean brain volume change = 0.04%, p = 0.57). The changes in brain volume and pseudo-T2 significantly correlated with each other, with marginal and conditional correlations (R2) of 0.44 and 0.65, respectively. Our results show that pseudo-T2 may be used in conjunction with the measures of brain volume to distinguish reversible water fluctuations and irreversible brain tissue loss (atrophy) and to investigate disease mechanisms related to neuro-inflammation, e.g., in multiple sclerosis, where edema-related water fluctuations may occur with disease activity and anti-inflammatory treatment. PMID:25379428

Nakamura, Kunio; Brown, Robert A.; Araujo, David; Narayanan, Sridar; Arnold, Douglas L.

2014-01-01

275

Acoustic Treatment Design Scaling Methods. Volume 5; Analytical and Experimental Data Correlation  

NASA Technical Reports Server (NTRS)

The primary purpose of the study presented in this volume is to present the results and data analysis of in-duct transmission loss measurements. Transmission loss testing was performed on full-scale, 1/2-scale, and 115-scale treatment panel samples. The objective of the study was to compare predicted and measured transmission loss for full-scale and subscale panels in an attempt to evaluate the variations in suppression between full- and subscale panels which were ostensibly of equivalent design. Generally, the results indicated an unsatisfactory agreement between measurement and prediction, even for full-scale. This was attributable to difficulties encountered in obtaining sufficiently accurate test results, even with extraordinary care in calibrating the instrumentation and performing the test. Test difficulties precluded the ability to make measurements at frequencies high enough to be representative of subscale liners. It is concluded that transmission loss measurements without ducts and data acquisition facilities specifically designed to operate with the precision and complexity required for high subscale frequency ranges are inadequate for evaluation of subscale treatment effects.

Chien, W. E.; Kraft, R. E.; Syed, A. A.

1999-01-01

276

Efficient generation of holographic news ticker in holographic 3DTV  

NASA Astrophysics Data System (ADS)

News ticker is used to show breaking news or news headlines in conventional 2-D broadcasting system. For the case of the breaking news, the fast creation is need, because the information should be sent quickly. In addition, if holographic 3- D broadcasting system is started in the future, news ticker will remain. On the other hands, some approaches for generation of CGH patterns have been suggested like the ray-tracing method and look-up table (LUT) method. However, these methods have some drawbacks that needs much time or needs huge memory size for look-up table. Recently, a novel LUT (N-LUT) method for fast generation of CGH patterns of 3-D objects with a dramatically reduced LUT without the loss of computational speed was proposed. Therefore, we proposed the method to efficiently generate the holographic news ticker in holographic 3DTV or 3-D movies using N-LUT method. The proposed method is largely consisted of five steps: construction of the LUT for each character, extraction of characters in news ticker, generation and shift of the CGH pattern for news ticker using the LUT for each character, composition of hologram pattern for 3-D video and hologram pattern for news ticker and reconstruct the holographic 3D video with news ticker. To confirm the proposed method, moving car in front of the castle is used as a 3D video and the words 'HOLOGRAM CAPTION GENERATOR' is used as a news ticker. From this simulation results confirmed the feasibility of the proposed method in fast generation of CGH patterns for holographic captions.

Kim, Seung-Cheol; Kim, Eun-Soo

2009-08-01

277

LCTV Holographic Imaging  

NASA Technical Reports Server (NTRS)

Astronauts are required to interface with complex systems that require sophisticated displays to communicate effectively. Lightweight, head-mounted real-time displays that present holographic images for comfortable viewing may be the ideal solution. We describe an implementation of a liquid crystal television (LCTV) as a spatial light modulator (SLM) for the display of holograms. The implementation required the solution of a complex set of problems. These include field calculations, determination of the LCTV-SLM complex transmittance characteristics and a precise knowledge of the signal mapping between the LCTV and frame grabbing board that controls it. Realizing the hologram is further complicated by the coupling that occurs between the phase and amplitude in the LCTV transmittance. A single drive signal (a gray level signal from a framegrabber) determines both amplitude and phase. Since they are not independently controllable (as is true in the ideal SLM) one must deal with the problem of optimizing (in some sense) the hologram based on this constraint. Solutions for the above problems have been found. An algorithm has been for field calculations that uses an efficient outer product formulation. Juday's MEDOF 7 (Minimum Euclidean Distance Optimal Filter) algorithm used for originally for filter calculations has been successfully adapted to handle metrics appropriate for holography. This has solved the problem of optimizing the hologram to the constraints imposed by coupling. Two laboratory methods have been developed for determining an accurate mapping of framegrabber pixels to LCTV pixels. A friendly software system has been developed that integrates the hologram calculation and realization process using a simple set of instructions. The computer code and all the laboratory measurement techniques determining SLM parameters have been proven with the production of a high quality test image.

Knopp, Jerome

1996-01-01

278

Direct view Holographic Autostereoscopic Displays  

E-print Network

@augustin.demon.co.uk We describe a new autostereoscopic display technology based on direct view Liquid Crystal Display (LCD) and Holographic Optical Elements (HOEs). The display uses a composite HOE to control interlaced spatially multiplexed stereo images displayed on the LCD to provide an easy to viewed

Bowden, Richard

279

Music holographic physiotherapy by laser  

NASA Astrophysics Data System (ADS)

Based on the relationship between music and nature, the paper compares laser and light with music sound on the principles of synergetics, describes music physically and objectively, and proposes a music holographic therapy by laser. Maybe it will have certain effects on mechanism study and clinical practice of the music therapy.

Liao, Changhuan

1996-09-01

280

A Holographic Fractional Topological Insulator  

E-print Network

We give a holographic realization of the recently proposed low energy effective action describing a fractional topological insulator. In particular we verify that the surface of this hypothetical material supports a fractional quantum Hall current corresponding to half that of a Laughlin state.

Carlos Hoyos-Badajoz; Kristan Jensen; Andreas Karch

2010-07-19

281

Universality class of holographic superconductors  

E-print Network

We study "holographic superconductors" in various spacetime dimensions. We compute most of the static critical exponents in the linear perturbations and show that they take the standard mean-field values. We also consider the dynamic universality class for these models and show that they belong to model A with dynamic critical exponent z=2.

Kengo Maeda; Makoto Natsuume; Takashi Okamura

2010-05-14

282

Holographic superconductivity in M theory.  

PubMed

Using seven-dimensional Sasaki-Einstein spaces we construct solutions of D=11 supergravity that are holographically dual to superconductors in three spacetime dimensions. Our numerical results indicate a new zero temperature solution dual to a quantum critical point. PMID:19905619

Gauntlett, Jerome P; Sonner, Julian; Wiseman, Toby

2009-10-01

283

Universality class of holographic superconductors  

SciTech Connect

We study ''holographic superconductors'' in various spacetime dimensions. We compute most of the static critical exponents in the linear perturbations and show that they take the standard mean-field values. We also consider the dynamic universality class for these models and show that they belong to model A with dynamic critical exponent z=2.

Maeda, Kengo; Natsuume, Makoto; Okamura, Takashi [Department of Engineering, Shibaura Institute of Technology, Saitama, 330-8570 (Japan); Theory Division, Institute of Particle and Nuclear Studies, KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801 (Japan); Department of Physics, Kwansei Gakuin University, Sanda, Hyogo, 669-1337 (Japan)

2009-06-15

284

Holographic dark-energy models  

NASA Astrophysics Data System (ADS)

Different holographic dark-energy models are studied from a unifying point of view. We compare models for which the Hubble scale, the future event horizon or a quantity proportional to the Ricci scale are taken as the infrared cutoff length. We demonstrate that the mere definition of the holographic dark-energy density generally implies an interaction with the dark-matter component. We discuss the relation between the equation-of-state parameter and the energy density ratio of both components for each of the choices, as well as the possibility of noninteracting and scaling solutions. Parameter estimations for all three cutoff options are performed with the help of a Bayesian statistical analysis, using data from supernovae type Ia and the history of the Hubble parameter. The ?CDM model is the clear winner of the analysis. According to the Bayesian information criterion (BIC), all holographic models should be considered as ruled out, since the difference ?BIC to the corresponding ?CDM value is >10. According to the Akaike information criterion (AIC), however, we find ?AIC<2 for models with Hubble-scale and Ricci-scale cutoffs, indicating, that they may still be competitive. As we show for the example of the Ricci-scale case, also the use of certain priors, reducing the number of free parameters to that of the ?CDM model, may result in a competitive holographic model.

Del Campo, Sergio; Fabris, Júlio. C.; Herrera, Ramón; Zimdahl, Winfried

2011-06-01

285

Generalized Holographic Dark Energy Model  

E-print Network

In this paper, the model of holographic Chaplygin gas has been extended to two general cases: first is the case of modified variable Chaplygin gas and secondly of the viscous generalized Chaplygin gas. The dynamics of the model are expressed by the use of scalar fields and the scalar potentials.

Mubasher Jamil; M. Umar Farooq; Muneer Ahmad Rashid

2009-05-28

286

Holographic diagnostics of biological microparticles  

NASA Astrophysics Data System (ADS)

Problem of studies of biological microojects is actual one for ecology, medicine, biology. Holographic techniques are useful to solve the problem. The above microojects are transparent or semitransparent ones in a visible light rather often. The case of an optically soft particle, (that is of a particle whose substance has the refractive index close to that of the surrounding medium) is quite probable in biological water suspensions. Some peculiarities of holographing optically soft microparticles are analyzed in this paper. We propose a technique to calculate a light intensity distribution in the plane of a hologram and in the plane of a holographic image of a particle of an arbitrary shape at an arbitrary distance from the latter plane. The efficiency of the approach proposed is demonstrated by calculational results obtained analytically for some simple cases. In a more complicated cases the technique can make a basis for numerical computations. The method of determining of refractive index of transparent and semitransparent microparticles is proposed. We also present in this paper some experimental results on holographic detection of the water drops and such optically soft particles as ovums of helmints in human jaundice.

Dyomin, Victor V.; Sokolov, Vladimir V.

1996-05-01

287

Holographic nondestructive testing of laminates  

NASA Technical Reports Server (NTRS)

Very small differences in laminate thickness result in interference fringes in holograph image. These indicate presence of unbonded area. Theoretical knowledge of membrane deflection may be used in conjunction with reduced number of pretest experiments to determine number of optical fringes that should appear for given laminate.

Stuckenberg, F. H.

1973-01-01

288

Measuring local volume fraction, long-wavelength correlations and fractionation in a phase-separating polydisperse fluid  

E-print Network

We dynamically simulate fractionation (partitioning of particle species) during spinodal gas-liquid separation of a size-polydisperse colloid, using polydispersity up to ~40% and a skewed parent size distribution. We introduce a novel coarse-grained Voronoi method to minimise size bias in measuring local volume fraction, along with a variety of spatial correlation functions which detect fractionation without requiring a clear distinction between the phases. These can be applied whether or not a system is phase separated, to determine structural correlations in particle size, and generalise easily to other kinds of polydispersity (charge, shape, etc.). We measure fractionation in both mean size and polydispersity between the phases, its direction differing between model interaction potentials which are identical in the monodisperse case. These qualitative features are predicted by a perturbative theory requiring only a monodisperse reference as input. The results show that intricate fractionation takes place almost from the start of phase separation, so can play a role even in nonequilibrium arrested states. The methods for characterisation of inhomogeneous polydisperse systems could in principle be applied to experiment as well as modelling.

John J. Williamson; R. Mike L. Evans

2014-09-23

289

Measuring local volume fraction, long-wavelength correlations, and fractionation in a phase-separating polydisperse fluid  

NASA Astrophysics Data System (ADS)

We dynamically simulate fractionation (partitioning of particle species) during spinodal gas-liquid separation of a size-polydisperse colloid, using polydispersity up to ˜40% and a skewed parent size distribution. We introduce a novel coarse-grained Voronoi method to minimise size bias in measuring local volume fraction, along with a variety of spatial correlation functions which detect fractionation without requiring a clear distinction between the phases. These can be applied whether or not a system is phase separated, to determine structural correlations in particle size, and generalise easily to other kinds of polydispersity (charge, shape, etc.). We measure fractionation in both mean size and polydispersity between the phases, its direction differing between model interaction potentials which are identical in the monodisperse case. These qualitative features are predicted by a perturbative theory requiring only a monodisperse reference as input. The results show that intricate fractionation takes place almost from the start of phase separation, so can play a role even in nonequilibrium arrested states. The methods for characterisation of inhomogeneous polydisperse systems could in principle be applied to experiment as well as modelling.

Williamson, J. J.; Evans, R. M. L.

2014-10-01

290

Measuring local volume fraction, long-wavelength correlations, and fractionation in a phase-separating polydisperse fluid  

SciTech Connect

We dynamically simulate fractionation (partitioning of particle species) during spinodal gas-liquid separation of a size-polydisperse colloid, using polydispersity up to ?40% and a skewed parent size distribution. We introduce a novel coarse-grained Voronoi method to minimise size bias in measuring local volume fraction, along with a variety of spatial correlation functions which detect fractionation without requiring a clear distinction between the phases. These can be applied whether or not a system is phase separated, to determine structural correlations in particle size, and generalise easily to other kinds of polydispersity (charge, shape, etc.). We measure fractionation in both mean size and polydispersity between the phases, its direction differing between model interaction potentials which are identical in the monodisperse case. These qualitative features are predicted by a perturbative theory requiring only a monodisperse reference as input. The results show that intricate fractionation takes place almost from the start of phase separation, so can play a role even in nonequilibrium arrested states. The methods for characterisation of inhomogeneous polydisperse systems could in principle be applied to experiment as well as modelling.

Williamson, J. J., E-mail: johnjosephwilliamson@gmail.com [Department of Physics, Institute for Soft Matter Synthesis and Metrology, Georgetown University, 37th and O Streets, N.W., Washington, D.C. 20057 (United States); Evans, R. M. L. [School of Mathematics, University of Leeds, Leeds LS2 9JT (United Kingdom)

2014-10-28

291

Nonlinear bivariate dependency of price-volume relationships in agricultural commodity futures markets: A perspective from Multifractal Detrended Cross-Correlation Analysis  

NASA Astrophysics Data System (ADS)

Nonlinear dependency between characteristic financial and commodity market quantities (variables) is crucially important, especially between trading volume and market price. Studies on nonlinear dependency between price and volume can provide practical insights into market trading characteristics, as well as the theoretical understanding of market dynamics. Actually, nonlinear dependency and its underlying dynamical mechanisms between price and volume can help researchers and technical analysts in understanding the market dynamics by integrating the market variables, instead of investigating them in the current literature. Therefore, for investigating nonlinear dependency of price-volume relationships in agricultural commodity futures markets in China and the US, we perform a new statistical test to detect cross-correlations and apply a new methodology called Multifractal Detrended Cross-Correlation Analysis (MF-DCCA), which is an efficient algorithm to analyze two spatially or temporally correlated time series. We discuss theoretically the relationship between the bivariate cross-correlation exponent and the generalized Hurst exponents for time series of respective variables. We also perform an empirical study and find that there exists a power-law cross-correlation between them, and that multifractal features are significant in all the analyzed agricultural commodity futures markets.

He, Ling-Yun; Chen, Shu-Peng

2011-01-01

292

Correlating anterior insula gray matter volume changes in young people with clinical and neurocognitive outcomes: an MRI study  

PubMed Central

Background The anterior insula cortex is considered to be both the structural and functional link between experience, affect, and behaviour. Magnetic resonance imaging (MRI) studies have shown changes in anterior insula gray matter volume (GMV) in psychosis, bipolar, depression and anxiety disorders in older patients, but few studies have investigated insula GMV changes in young people. This study examined the relationship between anterior insula GMV, clinical symptom severity and neuropsychological performance in a heterogeneous cohort of young people presenting for mental health care. Methods Participants with a primary diagnosis of depression (n?=?43), bipolar disorder (n?=?38), psychosis (n?=?32), anxiety disorder (n?=?12) or healthy controls (n?=?39) underwent structural MRI scanning, and volumetric segmentation of the bilateral anterior insula cortex was performed using the FreeSurfer application. Statistical analysis examined the linear and quadratic correlations between anterior insula GMV and participants’ performance in a battery of clinical and neuropsychological assessments. Results Compared to healthy participants, patients had significantly reduced GMV in the left anterior insula (t?=?2.05, p?=?.042) which correlated with reduced performance on a neuropsychological task of attentional set-shifting (??=?.32, p?=?.016). Changes in right anterior insula GMV was correlated with increased symptom severity (r?=?.29, p?=?.006) and more positive symptoms (r?=?.32, p?=?.002). Conclusions By using the novel approach of examining a heterogeneous cohort of young depression, anxiety, bipolar and psychosis patients together, this study has demonstrated that insula GMV changes are associated with neurocognitive deficits and clinical symptoms in such young patients. PMID:22607202

2012-01-01

293

Correlation between mean platelet volume and fasting plasma glucose levels in prediabetic and normoglycemic individuals  

PubMed Central

Background Prediabetes is an independent risk factor for cardiovascular diseases. Mean platelet volume (MPV) can reflect platelet activity, and high MPV is associated with thrombogenic activation and an increased risk of cardiovascular disease. In diabetic patients, MPV is higher when compared with normal subjects. However, the relationship between MPV and prediabetes is poorly understood. The purpose of the present study was to compare MPV in prediabetic and normoglycemic subjects, and to evaluate the relationship between MPV and fasting plasma glucose (FPG) levels in these two groups. Methods We retrospectively studied 1876 Japanese subjects who had undergone health checks at Iida Municipal Hospital. Age, sex, body mass index (BMI), blood pressure, medical history, smoking habits, alcohol intake, lipid profiles, FPG levels, and MPV were evaluated. Subjects were categorized into four groups according to FPG: Q1 (70 mg/dL ? FPG < 90 mg/dL, n = 467), Q2 (90 mg/dL ? FPG < 95 mg/dl, n = 457), Q3 (95 mg/dL ? FPG < 100 mg/dL, n = 442), and Q4 (100 mg/dL ? FPG < 126 mg/dL, n = 512). Q1, Q2, and Q3 were defined as normal FPG groups and Q4 was defined as prediabetic group. Results The MPV increased with the increasing FPG levels, in the following order: Q1 (9.89 ± 0.68 fl), Q2 (9.97 ± 0.69 fl), Q3 (10.02 ± 0.72 fl), and Q4 (10.12 ± 0.69 fl). After adjusting for the confounding parameters, MPV of the prediabetic group was higher than that in other groups (P < 0.001 for Q4 vs. Q1 and Q2, and P < 0.05 for Q4 vs. Q3). MPV in the high-normal glucose group (Q3) was significantly higher than in the low-normal glucose group (Q1). MPV was independently and positively associated with FPG, not only in prediabetic subjects but also in normal FPG subjects (? = 0.020 and ? = 0.006, respectively). Conclusions MPV in patients with prediabetes was higher than that in normal subjects, and was positively associated with FPG levels in prediabetic and normal subjects. PMID:23311535

2013-01-01

294

Label-Free Cytotoxicity Screening Assay by Digital Holographic Microscopy  

PubMed Central

Abstract We introduce a label-free technology based on digital holographic microscopy (DHM) with applicability for screening by imaging, and we demonstrate its capability for cytotoxicity assessment using mammalian living cells. For this first high content screening compatible application, we automatized a digital holographic microscope for image acquisition of cells using commercially available 96-well plates. Data generated through both label-free DHM imaging and fluorescence-based methods were in good agreement for cell viability identification and a Z?-factor close to 0.9 was determined, validating the robustness of DHM assay for phenotypic screening. Further, an excellent correlation was obtained between experimental cytotoxicity dose–response curves and known IC50 values for different toxic compounds. For comparable results, DHM has the major advantages of being label free and close to an order of magnitude faster than automated standard fluorescence microscopy. PMID:23062077

Kühn, Jonas; Shaffer, Etienne; Mena, Julien; Breton, Billy; Parent, Jérôme; Rappaz, Benjamin; Chambon, Marc; Emery, Yves; Magistretti, Pierre; Depeursinge, Christian; Marquet, Pierre

2013-01-01

295

Pattern-Recognition Processor Using Holographic Photopolymer  

NASA Technical Reports Server (NTRS)

proposed joint-transform optical correlator (JTOC) would be capable of operating as a real-time pattern-recognition processor. The key correlation-filter reading/writing medium of this JTOC would be an updateable holographic photopolymer. The high-resolution, high-speed characteristics of this photopolymer would enable pattern-recognition processing to occur at a speed three orders of magnitude greater than that of state-of-the-art digital pattern-recognition processors. There are many potential applications in biometric personal identification (e.g., using images of fingerprints and faces) and nondestructive industrial inspection. In order to appreciate the advantages of the proposed JTOC, it is necessary to understand the principle of operation of a conventional JTOC. In a conventional JTOC (shown in the upper part of the figure), a collimated laser beam passes through two side-by-side spatial light modulators (SLMs). One SLM displays a real-time input image to be recognized. The other SLM displays a reference image from a digital memory. A Fourier-transform lens is placed at its focal distance from the SLM plane, and a charge-coupled device (CCD) image detector is placed at the back focal plane of the lens for use as a square-law recorder. Processing takes place in two stages. In the first stage, the CCD records the interference pattern between the Fourier transforms of the input and reference images, and the pattern is then digitized and saved in a buffer memory. In the second stage, the reference SLM is turned off and the interference pattern is fed back to the input SLM. The interference pattern thus becomes Fourier-transformed, yielding at the CCD an image representing the joint-transform correlation between the input and reference images. This image contains a sharp correlation peak when the input and reference images are matched. The drawbacks of a conventional JTOC are the following: The CCD has low spatial resolution and is not an ideal square-law detector for the purpose of holographic recording of interference fringes. A typical state-of-the-art CCD has a pixel-pitch limited resolution of about 100 lines/mm. In contrast, the holographic photopolymer to be used in the proposed JTOC offers a resolution > 2,000 lines/mm. In addition to being disadvantageous in itself, the low resolution of the CCD causes overlap of a DC term and the desired correlation term in the output image. This overlap severely limits the correlation signal-to-noise ratio. The two-stage nature of the process limits the achievable throughput rate. A further limit is imposed by the low frame rate (typical video rates) of low- and medium-cost commercial CCDs.

Chao, Tien-Hsin; Cammack, Kevin

2006-01-01

296

TASI lectures on the Holographic Principle  

Microsoft Academic Search

These TASI lectures review the Holographic principle. The first lecture\\u000adescribes the puzzle of black hole information loss that led to the idea of\\u000aBlack Hole Complementarity and subsequently to the Holographic Principle\\u000aitself. The second lecture discusses the holographic entropy bound in general\\u000aspace-times. The final two lectures are devoted to the ADS\\/CFT duality as a\\u000aspecial case of

Daniela Bigatti; Leonard Susskind

2000-01-01

297

Holographic gravitational anomaly and chiral vortical effect  

Microsoft Academic Search

We analyze a holographic model with a pure gauge and a mixed gauge-gravitational Chern-Simons term in the action. These are the holographic implementations of the usual chiral and the mixed gauge-gravitational anomalies in four dimensional field theories with chiral fermions. We discuss the holographic renormalization and show that the gauge-gravitational Chern-Simons term does not induce new divergences. In order to

Karl Landsteiner; Eugenio Megías; Luis Melgar; Francisco Pena-Benitez

2011-01-01

298

Holographic entanglement entropy in general holographic superconductor models  

E-print Network

We study the entanglement entropy of general holographic dual models both in AdS soliton and AdS black hole backgrounds with full backreaction. We find that the entanglement entropy is a good probe to explore the properties of the holographic superconductors and provides richer physics in the phase transition. We obtain the effects of the scalar mass, model parameter and backreaction on the entropy, and argue that the jump of the entanglement entropy may be a quite general feature for the first order phase transition. In strong contrast to the insulator/superconductor system, we note that the backreaction coupled with the scalar mass can not be used to trigger the first order phase transition if the model parameter is below its bottom bound in the metal/superconductor system.

Yan Peng; Qiyuan Pan

2014-04-07

299

Holographic entanglement entropy in general holographic superconductor models  

NASA Astrophysics Data System (ADS)

We study the entanglement entropy of general holographic dual models both in AdS soliton and AdS black hole backgrounds with full backreaction. We find that the entanglement entropy is a good probe to explore the properties of the holographic superconductors and provides richer physics in the phase transition. We obtain the effects of the scalar mass, model parameter and backreaction on the entropy, and argue that the jump of the entanglement entropy may be a quite general feature for the first order phase transition. In strong contrast to the insulator/superconductor system, we note that the backreaction coupled with the scalar mass can not be used to trigger the first order phase transition if the model parameter is below its bottom bound in the metal/superconductor system.

Peng, Yan; Pan, Qiyuan

2014-06-01

300

Character process model for semen volume in AI rams: evaluation of correlation structures for long and short-term environmental effects  

Microsoft Academic Search

The objective of this study was to build a character process model taking into account serial correlations for the analysis of repeated measurements of semen volume in AI rams. For each ram, measurements were repeated within and across years. Therefore, we considered a model including three environmental effects: the long-term environmental effect, which is a random year* subject effect, the

Ingrid David; Loys Bodin; Gilles Lagriffoul; Eduardo Manfredi; Christèle Robert-Granié

2007-01-01

301

Frame-independent holographic conserved charges  

NASA Astrophysics Data System (ADS)

We propose the modified form of the conventional holographic conserved charges which provides us the frame-independent expressions for charges. This form is also shown to be independent of the holographic renormalization scheme. We show the frame and scheme independence through the matching of our holographic expression to the covariant bulk expression of conserved charges. As an explicit example, we consider five-dimensional Anti-de Sitter Kerr black holes and show that our form of holographic conserved charges gives us the identical expressions in the rotating and nonrotating frames.

Hyun, Seungjoon; Jeong, Jaehoon; Park, Sang-A.; Yi, Sang-Heon

2015-03-01

302

Serum vitamin D3 level inversely correlates with uterine fibroid volume in different ethnic groups: a cross-sectional observational study  

PubMed Central

Purpose Currently there is no effective medicinal treatment for uterine fibroids (UFs), a common health disorder that affects women of reproductive age. Identification of modifiable risk factors such as vitamin D (Vit D) deficiency could help develop novel strategies for the prevention and/or treatment of UFs. The purpose of this study was to identify whether low serum Vit D3 levels correlate with increased risk of UFs. Methods A total of 154 premenopausal women were recruited for this cross-sectional study. The control group comprised 50 subjects with a normal, fibroid-free uterine structure, confirmed by transvaginal ultrasonography. The 104 case subjects had at least one fibroid lesion that was 2 cm3 in volume or larger, confirmed by transvaginal ultrasonography. For each case subject, total uterine volume and total volume of all existing fibroids were measured in three perpendicular planes, with volume determined according to the prolate ellipse formula (a × b × c × 0.523), where a is height, b is width, and c is depth. Serum Vit D [25(OH) D3] levels were measured by radioimmunoassay. The independent t-test was used to compare serum Vit D levels across groups. Correlations were assessed by Spearman’s rank correlation test. Results Lower serum 25-(OH) Vit D levels were significantly associated with the occurrence of UFs (P = 0.01). A statistically significant inverse correlation was also observed between serum 25-(OH) Vit D levels and total UF volume (r = ?0.31; P = 0.002) within the case cohort. Subjects with larger fibroid volumes had lower serum Vit D levels and vice versa. Data stratified for ethnicity showed a statistically significant inverse correlation between serum 25-(OH) Vit D levels and total fibroid volume in black subjects (r = ?0.42; P = 0.001). An inverse correlation was also evident in white subjects (r = ?0.86; P = 0.58) but this did not reach statistical significance. Conclusion Lower serum Vit D levels are inversely correlated with UF burden in different ethnic groups. Vit D deficiency is a possible risk factor for the occurrence of UFs. PMID:23467803

Sabry, Mohamed; Halder, Sunil K; Allah, Abdou S Ait; Roshdy, Eman; Rajaratnam, Veera; Al-Hendy, Ayman

2013-01-01

303

Use Of A Holographic Lens For Producing Cylindrical Holographic Stereograms  

NASA Astrophysics Data System (ADS)

The production of cylindrical holographic stereograms, or multiplex holograms, requires the use of a large, low f/number cylindrical lens to form a line image on the holographic film. To have an image of reasonable size for display purposes, the f/number of the lens must be quite small, on the order of f/1, and the dimensions of the lens must be reasonably large, on the order of eight inches in width and height. The optical quality of the lens must also be quite good to prevent interference fringes in the image and to minimize the number of multiple exposures in the multiplexing process. For economic reasons, adjustable, oil-filled plastic lenses are commonly used for this purpose instead of conventional optics. Considerable difficulty is usually encountered, however, in adjusting the oil lens to minimize aberrations. Making the oil lens adequately adjustable, while at the same time maintaining the oil seal, also presents mechanical difficulties. We have eliminated these problems with the use of an off-axis, holographic cylindrical lens. The lens is easy to make, requires no adjustment, and has excellent optical quality. Techniques for producing this lens and its use in making multiplex holograms are described.

Fusek, Richard L.; Huff, Lloyd

1980-05-01

304

Use Of A Holographic Lens For Producing Cylindrical Holographic Stereograms  

NASA Astrophysics Data System (ADS)

The production of cylindrical holographic stereograms, or multiplex holograms, requires the use of a large, low f/number cylindrical lens to form a line image on the holographic film. To have an image of reasonable size for display purposes, the f/number of the lens must be quite small, on the order of f/1, and the dimensions of the lens must be reasonably large, on the order of eight inches in width and height. The optical quality of the lens must also be quite good to prevent interference fringes in the image and to minimize the number of multiple exposures in the multiplexing process. For economic rea-sons, adjustable, oil-filled plastic lenses are commonly used for this purpose instead of conventional optics. Considerable difficulty is usually encountered, however, in adjusting the oil lens to minimize aberrations. Making the oil lens adequately adjustable, while at the same time maintaining the oil seal, also presents mechanical difficUlties. We have eliminated these problems with the use of an off-axis, holographic cylindrical lens. The lens is easy to make, requires no adjustment, and has excellent optical quality. Techniques for producing this lens and its use in making multiplex holograms are described.

Fusek, Richard L.; Huff, Lloyd

1981-04-01

305

Holographic Jet Quenching  

NASA Astrophysics Data System (ADS)

In this dissertation we study the phenomenon of jet quenching in quark-gluon plasma using the AdS/CFT correspondence. We start with a weakly coupled, perturbative QCD approach to energy loss, and present a Monte Carlo code for computation of the DGLV radiative energy loss of quarks and gluons at an arbitrary order in opacity. We use the code to compute the radiated gluon distribution up to n=9 order in opacity, and compare it to the thin plasma (n=1) and the multiple soft scattering (n=infinity) approximations. We furthermore show that the gluon distribution at finite opacity depends in detail on the screening mass mu and the mean free path lambda. In the next part, we turn to the studies of how heavy quarks, represented as "trailing strings" in AdS/CFT, lose energy in a strongly coupled plasma. We study how the heavy quark energy loss gets modified in a "bottom-up" non-conformal holographic model, constructed to reproduce some properties of QCD at finite temperature and constrained by fitting the lattice gauge theory results. The energy loss of heavy quarks is found to be strongly sensitive to the medium properties. We use this model to compute the nuclear modification factor RAA of charm and bottom quarks in an expanding plasma with Glauber initial conditions, and comment on the range of validity of the model. The central part of this thesis is the energy loss of light quarks in a strongly coupled plasma. Using the standard model of "falling strings", we present an analytic derivation of the stopping distance of light quarks, previously available only through numerical simulations, and also apply it to the case of Gauss-Bonnet higher derivative gravity. We then present a general formula for computing the instantaneous energy loss in non-stationary string configurations. Application of this formula to the case of falling strings reveals interesting phenomenology, including a modified Bragg-like peak at late times and an approximately linear path dependence. Based on these results, we develop a phenomenological model of light quark energy loss and use it compute the nuclear modification factor RAA of light quarks in an expanding plasma. Comparison with the LHC pion suppression data shows that, although RAA has the right qualitative structure, the overall magnitude is too low, indicating that the predicted jet quenching is too strong. In the last part of the thesis we consider a novel idea of introducing finite momentum at endpoints of classical (bosonic and supersymmetric) strings, and the phenomenological consequences of this proposal on the energy loss of light quarks. We show that in a general curved background, finite momentum endpoints must propagate along null geodesics and that the distance they travel in an AdS5-Schwarzschild background is greater than in the previous treatments of falling strings. We also argue that this leads to a more realistic description of energetic quarks, allowing for an unambiguous way of distinguishing between the energy in the dual hard probe and the energy in the color fields surrounding it. This proposal also naturally allows for a clear and simple definition of the instantaneous energy loss. Using this definition and the "shooting string" initial conditions, we develope a new formula for light quark energy loss. Finally, we apply this formula to compute the nuclear modification factor RAA of light hadrons at RHIC and LHC, which, after the inclusion of the Gauss-Bonnet quadratic curvature corrections to the AdS5 geometry, shows a reasonably good agreement with the recent data.

Ficnar, Andrej

306

Compact, integrated dynamic holographic memory with refreshed holograms.  

PubMed

An innovative architecture for compact, integrated volume holographic memories is described. It is based on phase-conjugate readout and on a modulator-detector-memory array implemented in a silicon integrated circuit. The lensless memory module sustains dynamic read-write holograms by periodic refreshing. The integrated circuit is described and experimentally characterized. Holograms were stored in a prototype storage module that uses a 30 degrees -cut BaTiO(3) crystal and the 90 degrees recording geometry. As many as three angularly multiplexed holograms were periodically refreshed and subjected to >40% decay from exposure to the reference beam over 50 to 100 cycles. Experimental data are presented. PMID:18183264

Drolet, J J; Chuang, E; Barbastathis, G; Psaltis, D

1997-04-15

307

Holographic lattices, dimers, and glasses  

SciTech Connect

We holographically engineer a periodic lattice of localized fermionic impurities within a plasma medium by putting an array of probe D5-branes in the background produced by N D3-branes. Thermodynamic quantities are computed in the large N limit via the holographic dictionary. We then dope the lattice by replacing some of the D5-branes by anti-D5-branes. In the large N limit, we determine the critical temperature below which the system dimerizes with bond ordering. Finally, we argue that for the special case of a square lattice our system is glassy at large but finite N, with the low temperature physics dominated by a huge collection of metastable dimerized configurations without long-range order, connected only through tunneling events.

Kachru, Shamit; Karch, Andreas; Yaida, Sho [Kavli Institute for Theoretical Physics and Department of Physics, University of California, Santa Barbara, California 93106 (United States); Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States)

2010-01-15

308

Entropy balance in holographic superconductors  

E-print Network

In systems undergoing second order phase transitions, the temperature integral of the specific heat over temperature from zero to the critical temperature is the same in both the normal and ordered phases. This entropy balance relates the critical temperature to the distribution of degrees of freedom in the normal and ordered states. Quantum criticality and fractionalization can imply an increased number of low energy degrees of freedom in both the normal and ordered states. We explore the role of entropy balance in holographic models of superconductivity, focussing on the interplay between quantum criticality and superconductivity. We consider models with and without a ground state entropy density in the normal phase; the latter models are a new class of holographic superconductors. We explain how a normal phase entropy density manifests itself in the stable superconducting phase.

Sean A. Hartnoll; Razieh Pourhasan

2012-05-07

309

Holographic Type II Goldstone bosons  

E-print Network

The Goldstone theorem implies the appearance of an ungapped mode whenever a continuous global symmetry is spontaneously broken. In general it does not say anything about the precise form of the dispersion relation nor does it imply that there is one massless mode for each broken symmetry generator. It is a well-established fact that even for relativistic field theories in the presence of a chemical potential Goldstone modes with quadratic dispersion relation, the type II Goldstone bosons, appear in the spectrum. We develop two holographic models that feature type II Goldstone modes as part of the quasinormal mode spectrum. The models are based on simple generalizations with U(2) symmetry of the well-studied holographic s-wave superfluid. Our results include Goldstone modes without broken generators but with unusual realization of symmetries and a frequency dependent conductivity of striking resemblance to the one of Graphene.

Amado, Irene; Jimenez-Alba, Amadeo; Landsteiner, Karl; Melgar, Luis; Landea, Ignacio Salazar

2013-01-01

310

Holographic Type II Goldstone bosons  

E-print Network

The Goldstone theorem implies the appearance of an ungapped mode whenever a continuous global symmetry is spontaneously broken. In general it does not say anything about the precise form of the dispersion relation nor does it imply that there is one massless mode for each broken symmetry generator. It is a well-established fact that even for relativistic field theories in the presence of a chemical potential Goldstone modes with quadratic dispersion relation, the type II Goldstone bosons, appear in the spectrum. We develop two holographic models that feature type II Goldstone modes as part of the quasinormal mode spectrum. The models are based on simple generalizations with U(2) symmetry of the well-studied holographic s-wave superfluid. Our results include Goldstone modes without broken generators but with unusual realization of symmetries and a frequency dependent conductivity of striking resemblance to the one of Graphene.

Irene Amado; Daniel Arean; Amadeo Jimenez-Alba; Karl Landsteiner; Luis Melgar; Ignacio Salazar Landea

2013-03-20

311

Instantaneous Thermalization in Holographic Plasmas  

E-print Network

Thin-shell AdS-Vaidya spacetimes can be considered as holographic models of the thermalization process in strongly-coupled conformal field theories following a rapid injection of energy from an external source. While the expected thermalization time is the inverse temperature, Bhattacharyya and Minwalla have pointed out that bulk causality implies that expectation values of local field-theory observables actually take on their thermal values immediately following the injection. In this paper we study two-point functions, for which the causality argument does not apply. Specifically, we study the Brownian motion of a "quark" represented by a string stretching from the boundary to the horizon of an AdS_3-Vaidya spacetime. Surprisingly, we find that the two-point function also thermalizes instantly. Since Brownian motion is a 1/N effect, our result shows that, at least in certain cases, the rapid thermalization property of holographic plasmas persists beyond leading order in 1/N.

Hajar Ebrahim; Matthew Headrick

2011-03-15

312

Excluded volume and ion-ion correlation effects on the ionic atmosphere around B-DNA: Theory, simulations, and experiments  

NASA Astrophysics Data System (ADS)

The ionic atmosphere around a nucleic acid regulates its stability in aqueous salt solutions. One major source of complexity in biological activities involving nucleic acids arises from the strong influence of the surrounding ions and water molecules on their structural and thermodynamic properties. Here, we implement a classical density functional theory for cylindrical polyelectrolytes embedded in aqueous electrolytes containing explicit (neutral hard sphere) water molecules at experimental solvent concentrations. Our approach allows us to include ion correlations as well as solvent and ion excluded volume effects for studying the structural and thermodynamic properties of highly charged cylindrical polyelectrolytes. Several models of size and charge asymmetric mixtures of aqueous electrolytes at physiological concentrations are studied. Our results are in good agreement with Monte Carlo simulations. Our numerical calculations display significant differences in the ion density profiles for the different aqueous electrolyte models studied. However, similar results regarding the excess number of ions adsorbed to the B-DNA molecule are predicted by our theoretical approach for different aqueous electrolyte models. These findings suggest that ion counting experimental data should not be used alone to validate the performance of aqueous DNA-electrolyte models.

Ovanesyan, Zaven; Medasani, Bharat; Fenley, Marcia O.; Guerrero-García, Guillermo Iván; Olvera de la Cruz, Mónica; Marucho, Marcelo

2014-12-01

313

Excluded volume and ion-ion correlation effects on the ionic atmosphere around B-DNA: theory, simulations, and experiments.  

PubMed

The ionic atmosphere around a nucleic acid regulates its stability in aqueous salt solutions. One major source of complexity in biological activities involving nucleic acids arises from the strong influence of the surrounding ions and water molecules on their structural and thermodynamic properties. Here, we implement a classical density functional theory for cylindrical polyelectrolytes embedded in aqueous electrolytes containing explicit (neutral hard sphere) water molecules at experimental solvent concentrations. Our approach allows us to include ion correlations as well as solvent and ion excluded volume effects for studying the structural and thermodynamic properties of highly charged cylindrical polyelectrolytes. Several models of size and charge asymmetric mixtures of aqueous electrolytes at physiological concentrations are studied. Our results are in good agreement with Monte Carlo simulations. Our numerical calculations display significant differences in the ion density profiles for the different aqueous electrolyte models studied. However, similar results regarding the excess number of ions adsorbed to the B-DNA molecule are predicted by our theoretical approach for different aqueous electrolyte models. These findings suggest that ion counting experimental data should not be used alone to validate the performance of aqueous DNA-electrolyte models. PMID:25494770

Ovanesyan, Zaven; Medasani, Bharat; Fenley, Marcia O; Guerrero-García, Guillermo Iván; de la Cruz, Mónica Olvera; Marucho, Marcelo

2014-12-14

314

Increasing the Accuracy of Volume and ADC Delineation for Heterogeneous Tumor on Diffusion-Weighted MRI: Correlation with PET/CT  

SciTech Connect

Purpose: To improve the accuracy of volume and apparent diffusion coefficient (ADC) measurements in diffusion-weighted magnetic resonance imaging (MRI), we proposed a method based on thresholding both the b0 images and the ADC maps. Methods and Materials: In 21 heterogeneous lesions from patients with metastatic gastrointestinal stromal tumors (GIST), gross lesion were manually contoured, and corresponding volumes and ADCs were denoted as gross tumor volume (GTV) and gross ADC (ADC{sub g}), respectively. Using a k-means clustering algorithm, the probable high-cellularity tumor tissues were selected based on b0 images and ADC maps. ADC and volume of the tissues selected using the proposed method were denoted as thresholded ADC (ADC{sub thr}) and high-cellularity tumor volume (HCTV), respectively. The metabolic tumor volume (MTV) in positron emission tomography (PET)/computed tomography (CT) was measured using 40% maximum standard uptake value (SUV{sub max}) as the lower threshold, and corresponding mean SUV (SUV{sub mean}) was also measured. Results: HCTV had excellent concordance with MTV according to Pearson's correlation (r=0.984, P<.001) and linear regression (slope = 1.085, intercept = ?4.731). In contrast, GTV overestimated the volume and differed significantly from MTV (P=.005). ADC{sub thr} correlated significantly and strongly with SUV{sub mean} (r=?0.807, P<.001) and SUV{sub max} (r=?0.843, P<.001); both were stronger than those of ADC{sub g}. Conclusions: The proposed lesion-adaptive semiautomatic method can help segment high-cellularity tissues that match hypermetabolic tissues in PET/CT and enables more accurate volume and ADC delineation on diffusion-weighted MR images of GIST.

Gong, Nan-Jie [Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Wong, Chun-Sing, E-mail: drcswong@gmail.com [Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Chu, Yiu-Ching [Department of Radiology, Kwong Wah Hospital, Hong Kong (China); Guo, Hua [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing (China); Huang, Bingsheng [Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Chan, Queenie [Philips Healthcare, Hong Kong (China)

2013-10-01

315

Sound modes in holographic superfluids  

E-print Network

Superfluids support many different types of sound waves. We investigate the relation between the sound waves in a relativistic and a non-relativistic superfluid by using hydrodynamics to calculate the various sound speeds. Then, using a particular holographic scalar gravity realization of a strongly interacting superfluid, we compute first, second and fourth sound speeds as a function of the temperature. The relativistic low temperature results for second sound differ from Landau's well known prediction for the non-relativistic, incompressible case.

Christopher P. Herzog; Amos Yarom

2009-06-26

316

Advances in holographic particle velocimetry  

NASA Astrophysics Data System (ADS)

Holographic particle velocimetry (HPV) is a promising technique for 3D flow velocity and hence vorticity measurements to study turbulence, coherent structures and vortex interactions. We discuss various aspects in the development of this technique ranging from hologram recording configurations such as in-line, off-axis and multibeam to data processing. Difficulties in implementation are analyzed and solutions are discussed. We also present preliminary measurement results in a 3D vortex flow using one of our prototype HPV systems.

Simmons, Scott; Meng, Hui; Hussain, Fazle; Liu, David

1993-12-01

317

Gauss-Bonnet Holographic Superconductors  

NASA Astrophysics Data System (ADS)

We study a class of holographic superconductors dual to Einstein-Gauss-Bonnet AdS gravity coupled to nonlinear matter fields. We find an exact formula for the free energy of this system in any dimension and an approximate formula in terms of the thermodynamic quantities. We provide a simple method to select the couplings that admit charged black hole solutions in the bulk and have phase transitions on the boundary.

Miskovic, Olivera; Aranguiz, Ligeia

2015-01-01

318

Holographic bound and protein linguistics  

E-print Network

The holographic bound in physics constrains the complexity of life. The finite storage capability of information in the observable universe requires the protein linguistics in the evolution of life. We find that the evolution of genetic code determines the variance of amino acid frequencies and genomic GC content among species. The elegant linguistic mechanism is confirmed by the experimental observations based on all known entire proteomes.

Dirson Jian Li; Shengli Zhang

2007-04-10

319

Holographic system for nondestructive testing  

NASA Technical Reports Server (NTRS)

A description is given of a holographic system for nondestructive testing. The system is comprised of a mirror which illuminates the test object surface; the mirror is positionable to direct illumination on an object at varying angles with respect to a line normal to the surface of the object. In this manner holograms may be produced with varying degrees of sensitivity enabling optimum observation of dimensions of deformation of an object occurring between test exposures.

Kurtz, R. L. (inventor)

1975-01-01

320

Holographic description of gravitational anomalies  

NASA Astrophysics Data System (ADS)

The holographic duality can be extended to include quantum theories with the broken coordinate invariance leading to the appearance of the gravitational anomalies. On the gravity side one adds the gravitational Chern-Simons term to the bulk action which is gauge invariant only up to the boundary terms. We analyze in detail how the gravitational anomalies originate from the modified Einstein equations in the bulk. As a side observation, we find that the gravitational Chern-Simons functional has the interesting conformal properties. It is invariant under the conformal transformations. Moreover, its metric variation produces a conformal tensor which is a generalization of the Cotton tensor to dimension d+1 = 4k-1, kinZ. We calculate the modification of the holographic stress-energy tensor that is due to the Chern-Simons term and use the bulk Einstein equations to find its divergence and thus reproduce the gravitational anomaly. The explicit calculation of the anomaly is carried out in dimensions d = 2 and d = 6. The result of the holographic calculation is compared with that of the descent method and an agreement is found. The gravitational Chern-Simons term originates by the Kaluza-Klein mechanism from a one-loop modification of M-theory action. This modification is discussed in the context of the gravitational anomaly in the six-dimensional (2,0) theory. The agreement with the earlier conjectured anomaly is found.

Solodukhin, Sergey N.

2006-07-01

321

RGB digital lensless holographic microscopy  

NASA Astrophysics Data System (ADS)

The recent introduction of color digital lensless holographic microscopy (CDLHM) has shown the possibility of imaging microscopic specimens at full color without the need of lenses. Owing to the simplicity, robustness, and compactness of the digital lensless holographic microscopes (DLHM), they have been presented as the ideal candidates to being developed into portable holographic microscopes. However, in the case of CDLHM the utilization of three independent lasers hinders the portability option for this microscope. In this contribution an alternative to reduce the complexity of CDLHM aimed to recover the portability of this microscopy technology is presented. A super-bright white-light light-emitting diode (LED) is spectrally and spatially filtered to produce the needed illumination by CDLHM to work. CDLHM with LED illumination is used to image at full color a section of the head of a drosophila melanogaster fly (fruit fly). The LED-CDLHM method shows the capability of imaging objects of 2?m size in comparison with the micrometer resolution reported for LASER-CDLHM.

Garcia-Sucerquia, Jorge

2013-11-01

322

Linear and curvilinear correlations of brain gray matter volume and density with age using voxel-based morphometry with the Akaike information criterion in 291 healthy children.  

PubMed

We examined linear and curvilinear correlations of gray matter volume and density in cortical and subcortical gray matter with age using magnetic resonance images (MRI) in a large number of healthy children. We applied voxel-based morphometry (VBM) and region-of-interest (ROI) analyses with the Akaike information criterion (AIC), which was used to determine the best-fit model by selecting which predictor terms should be included. We collected data on brain structural MRI in 291 healthy children aged 5-18 years. Structural MRI data were segmented and normalized using a custom template by applying the diffeomorphic anatomical registration using exponentiated lie algebra (DARTEL) procedure. Next, we analyzed the correlations of gray matter volume and density with age in VBM with AIC by estimating linear, quadratic, and cubic polynomial functions. Several regions such as the prefrontal cortex, the precentral gyrus, and cerebellum showed significant linear or curvilinear correlations between gray matter volume and age on an increasing trajectory, and between gray matter density and age on a decreasing trajectory in VBM and ROI analyses with AIC. Because the trajectory of gray matter volume and density with age suggests the progress of brain maturation, our results may contribute to clarifying brain maturation in healthy children from the viewpoint of brain structure. PMID:22505237

Taki, Yasuyuki; Hashizume, Hiroshi; Thyreau, Benjamin; Sassa, Yuko; Takeuchi, Hikaru; Wu, Kai; Kotozaki, Yuka; Nouchi, Rui; Asano, Michiko; Asano, Kohei; Fukuda, Hiroshi; Kawashima, Ryuta

2013-08-01

323

Monitoring by holographic radar systems  

NASA Astrophysics Data System (ADS)

Nowadays, radar technology represents a significant opportunity to collect useful information for the monitoring and conservation of critical infrastructures. Radar systems exploit the non-invasive interaction between the matter and the electromagnetic waves at microwave frequencies. Such an interaction allows obtaining images of the region under test from which one can infer the presence of potential anomalies such as deformations, cracks, water infiltrations, etc. This information turns out to be of primary importance in practical scenarios where the probed structure is in a poor state of preservation and renovation works must be planned. In this framework, the aim of this contribution is to describe the potentialities of the holographic radar Rascan 4/4000, a holographic radar developed by Remote Sensing Laboratory of Bauman Moscow State Technical University, as a non-destructive diagnostic tool capable to provide, in real-time, high resolution subsurface images of the sounded structure [1]. This radar provides holograms of hidden anomalies from the amplitude of the interference signal arising between the backscattered signal and a reference signal. The performance of the holographic radar is appraised by means of several experiments. Preliminary tests concerning the imaging below the floor and inside wood structures are carried out in controlled conditions at the Electromagnetic Diagnostic Laboratory of IREA-CNR. After, with reference to bridge monitoring for security aim, the results of a measurement campaign performed on the Musmeci bridge are presented [2]. Acknowledgments This research has been performed in the framework of the "Active and Passive Microwaves for Security and Subsurface imaging (AMISS)" EU 7th Framework Marie Curie Actions IRSES project (PIRSES-GA-2010-269157). REFERENCES [1] S. Ivashov, V. Razevig, I. Vasilyev, A. Zhuravlev, T. Bechtel, L. Capineri, The holographic principle in subsurface radar technology, International Symposium to Commemorate the 60th Anniversary of the Invention of Holography, Springfield, Massachusetts USA, October 27-29, pp. 183-197, 2008. [2] I. Catapano, L. Crocco, A. F. Morabito, F. Soldovieri, "Tomographic imaging of holographic GPR data for non-invasive structural assessment: the Musmeci bridge investigation", Nondestructive testing and evaluation, vol. 27, pp. 229-237, 2012.

Catapano, Ilaria; Crocco, Lorenzo; Affinito, Antonio; Gennarelli, Gianluca; Soldovieri, Francesco

2013-04-01

324

Web service for digital holographic video processing  

NASA Astrophysics Data System (ADS)

A web-service for digital video hologram processing based on Berkeley Open Infrastructure for Network Computing (BOINC) is proposed. Proof-of-concept is confirmed for broad spectrum of applications such as digital holographic particle image velocimetry, water biomonitoring by means zooplankton analysis and digital holographic disdrometry. The snapshots presented in this paper were reconstructed using the proposed web-service.

Ekimov, Dmitry; Mäkynen, Anssi

2013-05-01

325

Holographic Estimate of Muon g-2  

E-print Network

I present recent calculations of the hadronic contributions to muon anomalous magnetic moment in holographic QCD, based on gauge/gravity duality. The holographic estimates are compared well with the analysis based on recently revised BaBar measurements of e+ e- -> pi+ pi- cross-sections and also with other model calculations for the light-by-light scattering contributions.

Deog Ki Hong

2010-04-05

326

Anticounterfeit holographic marks with secret codes  

NASA Astrophysics Data System (ADS)

The paper introduces the methods of making secret codes in the holograms for the purpose of anti-counterfeiting, especially the production of two kinds of visual holographic secret codes. The optical arrangements for recording are presented, and the effective results from using the visual secret codes into holographic trade marks are reported.

Liu, Shou; Zhang, Xiangsu; Lai, Hongkai

1993-11-01

327

Universal Resistivity from Holographic Massive Gravity  

E-print Network

Massive gravity provides a holographic model for theories exhibiting momentum dissipation. We provide an analytic expression for the DC conductivity. The result is universal, depending only on properties of the infra-red horizon, and holds at finite temperature and charge density. In addition, we provide a derivation of black hole thermodynamics in holographic massive gravity and show that the resulting physics is sensible.

Mike Blake; David Tong

2013-12-09

328

Holographic Three Dimensional Printer Using Galvanometer Scanners  

Microsoft Academic Search

To make holograms from computer graphic (CG) in a short time, a new holographic three dimensional (3D) printer is proposed here. This printer consists of galvanometer scanners, a micro computer and a laser, and uses a holographic contact duplicating method. Experiments have shown that a hologram of 39 × 41 mm can be obtained in 4 min.

Masahide Monde; Tsuyoshi Uematsu; Toshiki Toda; Kazuhiko Ohnuma; Yoshizumi Yasuda

1995-01-01

329

On quark masses in holographic QCD  

Microsoft Academic Search

Recently certain nonlocal operators were proposed to provide quark masses for the holographic model of QCD developed by Sakai and Sugimoto. The properties of these operators at strong coupling are examined in detail using holographic techniques. We find the renormalization procedure for these operators is modified by the running of the five-dimensional gauge coupling. We explicitly evaluate the chiral condensate

Robert McNees; Aninda Sinha

2008-01-01

330

Self-imaging chirped holographic optical waveguides.  

PubMed

To manipulate light propagation in optical waveguides, we have studied holographic, chirped structures within the waveguide's core. The holographic structures were embedded along the wave propagation direction and extended throughout the entire guide. Various self-imaging guides have been analyzed and realized to demonstrate the effect of different structures. PMID:18264499

Grebel, H; Graziani, J L; Vijayalakshmi, S; Shacklette, L W; Stengel, K M; Eldada, L; Norwood, R; Yardley, J T

1997-12-20

331

Self-Imaging Chirped Holographic Optical Waveguides  

Microsoft Academic Search

To manipulate light propagation in optical waveguides, we have studied holographic, chirped structures within the waveguide s core. The holographic structures were embedded along the wave propagation direction and extended throughout the entire guide. Various self-imaging guides have been analyzed and realized to demonstrate the effect of different structures.

Haim Grebel; Jean-Luc Graziani; Sankaran Vijayalakshmi; Lawrence W. Shacklette; Kelly M. T. Stengel; Louay Eldada; Robert Norwood; James T. Yardley

1997-01-01

332

Holographic recording of laser-induced plasma  

Microsoft Academic Search

We report on a holographic probing technique that allows for measurement of free-electron distribution with fine spatial detail. Plasma is generated by focusing a femtosecond pulse in air. We also demonstrate the capability of the holographic technique of capturing the time evolution of the plasma-generation process.

Martin Centurion; Ye Pu; Zhiwen Liu; Demetri Psaltis; Theodor W. Hänsch

2004-01-01

333

In-line FINCH super resolution digital holographic fluorescence microscopy using a high  

E-print Network

In-line FINCH super resolution digital holographic fluorescence microscopy using a high efficiency-efficiency, high-quality Fresnel incoherent correlation holography (FINCH) holograms using polarization sensitive (FINCH) [1] showed its potential for fluorescence microscopy [2], we have sought to perfect the technique

Rosen, Joseph

334

Application of self-developing dichromated gelatin for holographic data storage with speckle shift multiplexing  

Microsoft Academic Search

THe hologram multiplexing method for the 3D data storage with speckle reference wave is considered. It permits to multiplex holograms by shifting of the speckle wave on the value equal to the its correlation radius. The limit of the number of information units presented by this type of holographics storage exceeds the same value for the spectral or angular multiplexed

Nadya O. Reinhand; Yuri N. Denisyuk; Nina M. Ganzherli; Irina A. Maurer; Svetlana A. Pisarevskaya; V. B. Markov

1998-01-01

335

Holographic recording characteristics and applications of single-layer panchromatic dichromated gelatin material  

NASA Astrophysics Data System (ADS)

A high-quality single-layer panchromatic dichromated gelatin material is achieved successfully by employing new types of multi-color photosensitizers and photochemical promoters to conventional photo-crosslinking gelatin system. Its holographic recording characteristics such as spectral response, the photosensitivity of three primary colors, spectral selectivity of volume reflection hologram, angular and wavelength selectivity of volume transmission hologram, are studied in detail. Using red, green and blue lasers, namely three primary colors, the bright volume transmission and reflection holograms can be recorded on the panchromatic material at the exposure level of 30 mJ/cm2. Some preliminary results of space, angle and wavelength multiplexing holographic storage for storing multiple binary and grey-tone optical images, are also reported in this paper.

Zhu, Jianhua; Xu, Min; Chen, Ligong; Guo, Yongkang; Guo, Lurong

2005-09-01

336

A Holographic Framework for Eternal Inflation  

E-print Network

In this paper we provide some circumstantial evidence for a holographic duality between bubble nucleation in an eternally inflating universe and a Euclidean conformal field theory. The holographic correspondence (which is different than Strominger's dS/CFT duality) relates the decay of (3+1)-dimensional de Sitter space to a two-dimensional CFT. It is not associated with pure de Sitter space, but rather with Coleman-De Luccia bubble nucleation. Alternatively, it can be thought of as a holographic description of the open, infinite, FRW cosmology that results from such a bubble. The conjectured holographic representation is of a new type that combines holography with the Wheeler-DeWitt formalism to produce a Wheeler-DeWitt theory that lives on the spatial boundary of a k=-1 FRW cosmology. We also argue for a more ambitious interpretation of the Wheeler-DeWitt CFT as a holographic dual of the entire Landscape.

Freivogel, B; Susskind, L; Yeh, C P; Freivogel, Ben; Sekino, Yasuhiro; Susskind, Leonard; Yeh, Chen-Pin

2006-01-01

337

Periadolescent ethanol vapor exposure produces reductions in hippocampal volume that are correlated with deficits in prepulse inhibition of the startle  

PubMed Central

BACKGROUND Epidemiological studies suggest that excessive alcohol consumption is prevalent among adolescents and may have lasting neurobehavioral consequences. The use of animal models allows for the separation of the effects of adolescent ethanol exposure from genetic background and other environmental insults. In the present study the effects of moderate ethanol vapor exposure, during adolescence, on structural diffusion tensor imaging (DTI) and behavioral measures were evaluated in adulthood. METHODS A total of 53 Wistar rats were received at postnatal day (PD) 21, and were randomly assigned to ethanol vapor (14 hrs on/10 hrs off/day) or air exposure for 35 days from PD 23-PD 58 (average blood ethanol concentration (BEC): 169 mg%). Animals were received in two groups that were subsequently sacrificed at two time points following withdrawal from ethanol vapor: (1) at 72 days of age, 2 weeks following withdrawal or (2) at day 128, 10 weeks following withdrawal. In the second group, behavior in the light/dark box and prepulse inhibition of the startle (PPI) were also evaluated. Fifteen animals in each group were scanned, post mortem, for structural DTI. RESULTS There were no significant differences in body weight between ethanol and control animals. Volumetric data, demonstrated that total brain, hippocampal, corpus callosum but not ventricular volume was significantly larger in the 128 day sacrificed animals as compared to the 72 day animals. The hippocampus was smaller and the ventricles larger at 128 days as compared to 72 days, in the ethanol exposed animals, leading to a significant group × time effect. Ethanol exposed animals sacrificed at 128 days also had diminished PPI and more rears in the light box that were significantly correlated with hippocampal size. CONCLUSIONS These studies demonstrate that DTI volumetric measures of hippocampus are significantly impacted by age and periadolescent ethanol exposure and withdrawal in Wistar rats. PMID:23578102

Ehlers, Cindy L.; Oguz, Ipek; Budin, Francois; Wills, Derek N.; Crews, Fulton T.

2013-01-01

338

Digital holographic microscopy for microalgae biovolume assessment  

NASA Astrophysics Data System (ADS)

The relative amount of biomass in a body of water is one of the various indicators widely used in water quality evaluation. This implies complex tasks such as identification and characterization of microorganisms and measurement of their biovolume. Particularly, the latter is estimated by assuming simple geometrical shapes for the microorganism and by calculating its dimensions from images taken with a conventional microscope. In order to have a more precise and automatic method for biovolume evaluation, a hybrid methodology based on digital holographic microscopy and image processing is proposed. The whole volume of a specimen under study is obtained combining the phase contrast image of an off-axis hologram with the thickness-profile data of the specimen extracted from the cell silhouette. This technique has been used for determining the biovolume of Ceratium Hirundinella cells in water samples. The methodology proposed also shows that it is possible to estimate accurately an effective refractive index of the microorganism. Experimental results have shown that this technique is not only an efficient and fast alternative, but also suitable for automatizing the entire process.

Monaldi, Andrea C.; Romero, Gladis G.; Alanís, Elvio E.; Cabrera, Carlos M.

2015-02-01

339

Holographic Quantum States  

SciTech Connect

We show how continuous matrix product states of quantum fields can be described in terms of the dissipative nonequilibrium dynamics of a lower-dimensional auxiliary boundary field by demonstrating that the spatial correlation functions of the bulk field correspond to the temporal statistics of the boundary field. This equivalence (1) illustrates an intimate connection between the theory of continuous quantum measurement and quantum field theory, (2) gives an explicit construction of the boundary field allowing the extension of real-space renormalization group methods to arbitrary dimensional quantum field theories without the introduction of a lattice parameter, and (3) yields a novel interpretation of recent cavity QED experiments in terms of quantum field theory, and hence paves the way toward observing genuine quantum phase transitions in such zero-dimensional driven quantum systems.

Osborne, Tobias J.; Eisert, Jens [Wissenschaftskolleg zu Berlin, Berlin 14193 (Germany); Verstraete, Frank [University of Vienna, Faculty of Physics, Boltzmanngasse 5, A-1090 Wien (Austria)

2010-12-31

340

50 years of holographic interferometry  

NASA Astrophysics Data System (ADS)

Fifty years ago, Robert L. Powell and I discovered holographic interferometry while working at the Radar Laboratory of the University of Michigan's Institute of Science and Technology. I have worked in this field for this entire time span, watched it grow from an unexplored technology to become a widespread industrial testing method, and I have contributed to these developments. In this paper, I will trace my history in this field from our discovery to my involvement in its theory and applications. I will conclude with a discussion of digital holography, which is currently replacing photographic holography for most research and industrial applications.

Stetson, Karl A.

2015-01-01

341

Holographic recording of fast phenomena  

NASA Astrophysics Data System (ADS)

We report on a holographic method for recording fast events whose speed is limited by the laser pulse duration if the recording material has sufficient sensitivity to reliably record a frame of the fast event with a single pulse. The method we describe uses the angular selectivity of thick holograms to resolve frames that are recorded with adjacent pulses. Two specially designed cavities are used to generate the signal and reference pulse trains. We experimentally demonstrate the system by recording laser induced shock waves with a temporal resolution of 5.9 ns, limited by the pulse width of the Q-switched Nd:yttrium-aluminum-garnet laser used in the experiments.

Liu, Zhiwen; Steckman, Gregory J.; Psaltis, Demetri

2002-02-01

342

Fourth sound of holographic superfluids  

E-print Network

We compute fourth sound for superfluids dual to a charged scalar and a gauge field in an AdS_4 background. For holographic superfluids with condensates that have a large scaling dimension (greater than approximately two), we find that fourth sound approaches first sound at low temperatures. For condensates that a have a small scaling dimension it exhibits non-conformal behavior at low temperatures which may be tied to the non-conformal behavior of the order parameter of the superfluid. We show that by introducing an appropriate scalar potential, conformal invariance can be enforced at low temperatures.

Amos Yarom

2009-05-08

343

Holographic Estimate of Electromagnetic Mass  

E-print Network

Using the gauge/gravity duality, we calculate the electromagnetic contributions to hadron masses, where mass generates dynamically by strong QCD interactions. Based on the Sakai-Sugimoto model of holographic QCD we find that the electromagnetic mass of proton is 0.48 MeV larger than that of neutron, which is in agreement with recent lattice results. Similarly for pions we obtain $m_{\\pi^{\\pm}}-m_{\\pi^0}$=3.6 ~ 7.2 MeV, close to the experimental value, taking a ultraviolet cutoff $\\Lambda\\simeq 4M_{\\rm KK}$.

Deog Ki Hong

2015-01-26

344

Type IIB Holographic Superfluid Flows  

E-print Network

We construct fully backreacted holographic superfluid flow solutions in a five-dimensional theory that arises as a consistent truncation of low energy type IIB string theory. We construct a black hole with scalar and vector hair in this theory, and study the phase diagram. As expected, the superfluid phase ceases to exist for high enough superfluid velocity, but we show that the phase transition between normal and superfluid phases is always second order. We also analyze the zero temperature limit of these solutions. Interestingly, we find evidence that the emergent IR conformal symmetry of the zero-temperature domain wall is broken at high enough velocity.

Arean, Daniel; Krishnan, Chethan; Prochazka, Tomas

2010-01-01

345

Type IIB holographic superfluid flows  

NASA Astrophysics Data System (ADS)

We construct fully backreacted holographic superfluid flow solutions in a five-dimensional theory that arises as a consistent truncation of low energy type IIB string theory. We construct a black hole with scalar and vector hair in this theory, and study the phase diagram. As expected, the superfluid phase ceases to exist for high enough superfluid velocity, but we show that the phase transition between normal and superfluid phases is always second order. We also analyze the zero temperature limit of these solutions. Interestingly, we find evidence that the emergent IR conformal symmetry of the zero-temperature domain wall is broken at high enough velocity.

Areán, Daniel; Bertolini, Matteo; Krishnan, Chethan; Procházka, Tomáš

2011-03-01

346

Type IIB Holographic Superfluid Flows  

E-print Network

We construct fully backreacted holographic superfluid flow solutions in a five-dimensional theory that arises as a consistent truncation of low energy type IIB string theory. We construct a black hole with scalar and vector hair in this theory, and study the phase diagram. As expected, the superfluid phase ceases to exist for high enough superfluid velocity, but we show that the phase transition between normal and superfluid phases is always second order. We also analyze the zero temperature limit of these solutions. Interestingly, we find evidence that the emergent IR conformal symmetry of the zero-temperature domain wall is broken at high enough velocity.

Daniel Arean; Matteo Bertolini; Chethan Krishnan; Tomas Prochazka

2011-04-20

347

Generalized Superconductors and Holographic Optics  

E-print Network

We study generalized holographic s-wave superconductors in four dimensional R-charged black hole and Lifshitz black hole backgrounds, in the probe limit. We first establish the superconducting nature of the boundary theories, and then study their optical properties. Numerical analysis indicates that a negative Depine-Lakhtakia index may appear at low frequencies in the theory dual to the R-charged black hole, for certain temperature ranges, for specific values of the charge parameter. The corresponding cut-off values for these are numerically established in several cases. Such effects are seen to be absent in the Lifshitz background where this index is always positive.

Subhash Mahapatra; Prabwal Phukon; Tapobrata Sarkar

2014-03-31

348

Holographic Superconductors with Lifshitz Scaling  

E-print Network

Black holes in asymptotically Lifshitz spacetime provide a window onto finite temperature effects in strongly coupled Lifshitz models. We add a Maxwell gauge field and charged matter to a recently proposed gravity dual of 2+1 dimensional Lifshitz theory. This gives rise to charged black holes with scalar hair, which correspond to the superconducting phase of holographic superconductors with z > 1 Lifshitz scaling. Along the way we analyze the global geometry of static, asymptotically Lifshitz black holes at arbitrary critical exponent z > 1. In all known exact solutions there is a null curvature singularity in the black hole region, and, by a general argument, the same applies to generic Lifshitz black holes.

E. J. Brynjolfsson; U. H. Danielsson; L. Thorlacius; T. Zingg

2010-03-27

349

Holographic bounds and finite inflation  

NASA Astrophysics Data System (ADS)

We compare two holographic arguments that impose especially strong bounds on the amount of inflation. One comes from the de Sitter equilibrium cosmology and the other from the work of Banks and Fischler. We find that simple versions of these two approaches yield the same bound on the number of e-foldings. A careful examination reveals that while these pictures are similar in spirit, they are not necessarily identical prescriptions. We apply the two pictures to specific cosmologies which expose potentially important differences and which also demonstrate ways these seemingly simple proposals can be tricky to implement in practice.

Phillips, Daniel; Scacco, Andrew; Albrecht, Andreas

2015-02-01

350

Holographic Viscosity of Fundamental Matter  

E-print Network

A holographic dual of a finite-temperature SU(N_c) gauge theory with a small number of flavours N_f viscosity to entropy ratio in these theories saturates the conjectured universal bound eta/s >= 1/4\\pi. The contribution of the fundamental matter eta_fund is therefore enhanced at strong 't Hooft coupling lambda; for example, eta_fund ~ lambda N_c N_f T^3 in four dimensions. Other transport coefficients are analogously enhanced. These results hold with or without a baryon number chemical potential.

David Mateos; Robert C. Myers; Rowan M. Thomson

2006-10-16

351

Raman and Rayleigh holographic lidar.  

PubMed

We have designed a novel rotational Raman and Rayleigh lidar system that incorporates a simple holographic optical element. The hologram simultaneously disperses and focuses the backscattered signal light so that narrow spectral features can be isolated and detected with high efficiency. By measuring the relative strength of several nitrogen rotational Raman lines, we can obtain an accurate temperature of the atmosphere at a given altitude without the need for external calibration. Simultaneous photon counting of the Rayleigh backscatter signal permits temperature measurements at much higher altitudes. PMID:11921811

Andersen, Geoff; Brasseur, Jason K; Knize, Randall J; Haris, Paul

2002-03-20

352

Holographic superconducting quantum interference device  

NASA Astrophysics Data System (ADS)

We present a holographic model of the SQUID (Superconducting QUantum Interference Device) in the external magnetic field. The model of the gravitational theory considered in this paper is the Einstein-Maxwell-complex scalar model on the four-dimensional anti-de Sitter Schwarzschild black brane geometry, where one space direction is compacted into a circle and we arrange the coefficient of the time components profile so that we can model the SQUID, where the profile plays the role of the chemical potential for the Cooper pair.

Takeuchi, Shingo

2015-03-01

353

A holographic model of SQUID  

E-print Network

We construct a holographic model of superconducting quantum interference device (SQUID) in the Einstein-Maxwell-complex scalar theory with a negative cosmological constant. The SQUID ring consists of two Josephson junctions which sit on two sides of a compactified spatial direction of a Schwarzschild-AdS black brane. These two junctions interfere with each other and then result in a total current depending on the magnetic flux, which can be deduced from the phase differences of the two Josephson junctions. The relation between the total current and the magnetic flux is obtained numerically.

Rong-Gen Cai; Yong-Qiang Wang; Hai-Qing Zhang

2013-12-16

354

A holographic model of SQUID  

E-print Network

We construct a holographic model of superconducting quantum interference device (SQUID) in the Einstein-Maxwell-complex scalar theory with a negative cosmological constant. The SQUID ring consists of two Josephson junctions which sit on two sides of a compactified spatial direction of a Schwarzschild-AdS black brane. These two junctions interfere with each other and then result in a total current depending on the magnetic flux, which can be deduced from the phase differences of the two Josephson junctions. The relation between the total current and the magnetic flux is obtained numerically.

Cai, Rong-Gen; Zhang, Hai-Qing

2013-01-01

355

On Holographic Insulators and Supersolids  

E-print Network

We obtain holographic realisations for systems that have strong similarities to Mott insulators and supersolids, after examining the ground states of Einstein-Maxwell-scalar systems. The real part of the AC conductivity has a hard gap and a discrete spectrum only. We add momentum dissipation to resolve the delta function in the conductivity due to translational invariance. We develop tools to directly calculate the Drude weight for a large class of solutions and to support our claims. Numerical RG flows are also constructed to verify that such saddle points are IR fixed points of asymptotically AdS_4 geometries.

Kiritsis, Elias

2015-01-01

356

Impact of the radiotherapy technique on the correlation between dose-volume histograms of the bladder wall defined on MRI imaging and dose-volume/surface histograms in prostate cancer patients  

NASA Astrophysics Data System (ADS)

The aim of this study was to evaluate the correlation between the ‘true’ absolute and relative dose-volume histograms (DVHs) of the bladder wall, dose-wall histogram (DWH) defined on MRI imaging and other surrogates of bladder dosimetry in prostate cancer patients, planned both with 3D-conformal and intensity-modulated radiation therapy (IMRT) techniques. For 17 prostate cancer patients, previously treated with radical intent, CT and MRI scans were acquired and matched. The contours of bladder walls were drawn by using MRI images. External bladder surfaces were then used to generate artificial bladder walls by performing automatic contractions of 5, 7 and 10 mm. For each patient a 3D conformal radiotherapy (3DCRT) and an IMRT treatment plan was generated with a prescription dose of 77.4 Gy (1.8 Gy/fr) and DVH of the whole bladder of the artificial walls (DVH-5/10) and dose-surface histograms (DSHs) were calculated and compared against the DWH in absolute and relative value, for both treatment planning techniques. A specific software (VODCA v. 4.4.0, MSS Inc.) was used for calculating the dose-volume/surface histogram. Correlation was quantified for selected dose-volume/surface parameters by the Spearman correlation coefficient. The agreement between %DWH and DVH5, DVH7 and DVH10 was found to be very good (maximum average deviations below 2%, SD < 5%): DVH5 showed the best agreement. The correlation was slightly better for absolute (R = 0.80-0.94) compared to relative (R = 0.66-0.92) histograms. The DSH was also found to be highly correlated with the DWH, although slightly higher deviations were generally found. The DVH was not a good surrogate of the DWH (R < 0.7 for most of parameters). When comparing the two treatment techniques, more pronounced differences between relative histograms were seen for IMRT with respect to 3DCRT (p < 0.0001).

Maggio, Angelo; Carillo, Viviana; Cozzarini, Cesare; Perna, Lucia; Rancati, Tiziana; Valdagni, Riccardo; Gabriele, Pietro; Fiorino, Claudio

2013-04-01

357

Pixel size limit in holographic memories.  

PubMed

The bandwidth of holographic recording in LiNbO(3) (Fe doped) in the 90 degrees geometry is studied theoretically and experimentally. The wide holographic bandwidth of LiNbO(3) makes it possible to record submicrometer pixels and reconstruct them by phase conjugation in a holographic memory system. This approach reduces the system cost and increases the system storage density. We demonstrate the recording and the phase-conjugate reconstruction of various pixel sizes down to 1 mumx1 mum . The signal-noise ratio and the bit-error rate are examined. PMID:18079797

Liu, W; Psaltis, D

1999-10-01

358

TASI lectures on the Holographic Principle  

E-print Network

These TASI lectures review the Holographic principle. The first lecture describes the puzzle of black hole information loss that led to the idea of Black Hole Complementarity and subsequently to the Holographic Principle itself. The second lecture discusses the holographic entropy bound in general space-times. The final two lectures are devoted to the ADS/CFT duality as a special case of the principle. The presentation is self contained and emphasizes the physical principles. Very little technical knowledge of string theory or supergravity is assumed.

Daniela Bigatti; Leonard Susskind

2000-02-05

359

Holographic Monopole Catalysis of Baryon Decay  

E-print Network

We study how monopole catalysis of baryon decay is realized in holographic QCD. Physics of monopole catalysis becomes much simpler in holographic description as it occurs due to the violation of the Bianchi identity for the 5D gauge symmetry when magnetic monopole is present. In holographic QCD we find a unified picture of the baryon number violation under magnetic monopole or electroweak sphaleron, giving a new mechanism of baryon number violation. We also embed our set-up in the string theory model by Sakai and Sugimoto.

Deog Ki Hong; Ki-Myeong Lee; Cheonsoo Park; Ho-Ung Yee

2008-04-22

360

Effects of wavelength change in holographic reconstructions  

NASA Astrophysics Data System (ADS)

Holographic imaging is necessary in some particulate measurements in test facilities at AEDC. Additionally, projection of holographic images of infrared (IR) test objects is being considered to enhance the IR sensor test capability at AEDC. Lasers of different wavelengths often are necessary in the recording and reconstruction of the required holograms. As a result, a study of the effects of a wavelength change between the recording and reconstruction illumination on the aberration, resolution, and location of holographically reconstructed images was experimentally undertaken. Control of aberration and resolution degradation, to the extent possible, is described.

Menzel, R. W.

1981-08-01

361

a Realization of the Holographic Entropy  

NASA Astrophysics Data System (ADS)

The entropy bound for the conventional quantum field theory is known as A3/4. Thus, there is an entropy gap from A3/4 to the holographic entropy A. In this paper, we show that the entropy gap can be overcome by introducing internal degrees of freedom to the system. Using a state counting method, we show explicitly how the familiar holographic thermodynamics with area entropy can be realized. It may help in the understanding of the microscopic origin of the holographic entropy.

Xiao, Yong; Yang, Guang

2013-04-01

362

Holographic holes and differential entropy  

NASA Astrophysics Data System (ADS)

Recently it has been shown that the Bekenstein-Hawking entropy formula evaluated on certain closed surfaces in the bulk of a holographic spacetime has an interpretation as the differential entropy of a particular family of intervals (or strips) in the boundary theory [1, 2]. We first extend this construction to bulk surfaces which vary in time. We then give a general proof of the equality between the gravitational entropy and the differential entropy. This proof applies to a broad class of holographic backgrounds possessing a generalized planar symmetry and to certain classes of higher-curvature theories of gravity. To apply this theorem, one can begin with a bulk surface and determine the appropriate family of boundary intervals by considering extremal surfaces tangent to the given surface in the bulk. Alternatively, one can begin with a family of boundary intervals; as we show, the differential entropy then equals the gravitational entropy of a bulk surface that emerges from the intersection of the neighboring entanglement wedges, in a continuum limit.

Headrick, Matthew; Myers, Robert C.; Wien, Jason

2014-10-01

363

Holographic opto-fluidic microscopy  

PubMed Central

Over the last decade microfluidics has created a versatile platform that has significantly advanced the ways in which micro-scale organisms and objects are controlled, processed and investigated, by improving the cost, compactness and throughput aspects of analysis. Microfluidics has also expanded into optics to create reconfigurable and flexible optical devices such as reconfigurable lenses, lasers, waveguides, switches, and on-chip microscopes. Here we present a new opto-fluidic microscopy modality, i.e., Holographic Opto-fluidic Microscopy (HOM), based on lensless holographic imaging. This imaging modality complements the miniaturization provided by microfluidics and would allow the integration of microscopy into existing on-chip microfluidic devices with various functionalities. Our imaging modality utilizes partially coherent in-line holography and pixel super-resolution to create high-resolution amplitude and phase images of the objects flowing within micro-fluidic channels, which we demonstrate by imaging C. elegans, Giardia lamblia, and Mulberry pollen. HOM does not involve complicated fabrication processes or precise alignment, nor does it require a highly uniform flow of objects within microfluidic channels. PMID:21197025

Bishara, Waheb; Zhu, Hongying; Ozcan, Aydogan

2010-01-01

364

A Holographic Twin Higgs Model  

E-print Network

We present a UV completion of the twin Higgs idea in the framework of holographic composite Higgs. The SM contribution to the Higgs potential is effectively cut off by the SM-singlet mirror partners at the sigma-model scale f, naturally allowing for m_{KK} beyond the LHC reach. The bulk symmetry is SU(7) X SO(8), broken on the IR brane into SU(7) X SO(7) and on the UV brane into (SU(3) X SU(2) X U(1))^{SM} X (SU(3) X SU(2) X U(1))^{mirror} X Z2. The field content on the UV brane is the SM, extended by a sector transforming under the mirror gauge group, with the Z2 exchanging the two sectors. An additional Z2 breaking term is holographically generated to reproduce the Higgs mass and VEV, with a mild O(10%) tuning. This model has no trace at the LHC, but can by probed by precision Higgs measurements at future lepton colliders, and by direct searches for KK excitations at a 100 TeV collider.

Michael Geller; Ofri Telem

2014-11-11

365

Analyticity and the Holographic S-Matrix  

SciTech Connect

We derive a simple relation between the Mellin amplitude for AdS/CFT correlation functions and the bulk S-Matrix in the flat spacetime limit, proving a conjecture of Penedones. As a consequence of the Operator Product Expansion, the Mellin amplitude for any unitary CFT must be a meromorphic function with simple poles on the real axis. This provides a powerful and suggestive handle on the locality vis-a-vis analyticity properties of the S-Matrix. We begin to explore analyticity by showing how the familiar poles and branch cuts of scattering amplitudes arise from the holographic description. For this purpose we compute examples of Mellin amplitudes corresponding to 1-loop and 2-loop Witten diagrams in AdS. We also examine the flat spacetime limit of conformal blocks, implicitly relating the S-Matrix program to the Bootstrap program for CFTs. We use this connection to show how the existence of small black holes in AdS leads to a universal prediction for the conformal block decomposition of the dual CFT.

Fitzpatrick, A.Liam; /Stanford U., Phys. Dept.; Kaplan, Jared; /SLAC

2012-04-03

366

Unitarity and the Holographic S-Matrix  

SciTech Connect

The bulk S-Matrix can be given a non-perturbative definition in terms of the flat space limit of AdS/CFT. We show that the unitarity of the S-Matrix, ie the optical theorem, can be derived by studying the behavior of the OPE and the conformal block decomposition in the flat space limit. When applied to perturbation theory in AdS, this gives a holographic derivation of the cutting rules for Feynman diagrams. To demonstrate these facts we introduce some new techniques for the analysis of conformal field theories. Chief among these is a method for conglomerating local primary operators O{sub 1} and O{sub 2} to extract the contribution of an individual primary O{sub {Delta},{ell}} in their OPE. This provides a method for isolating the contribution of specific conformal blocks which we use to prove an important relation between certain conformal block coefficients and anomalous dimensions. These techniques make essential use of the simplifications that occur when CFT correlators are expressed in terms of a Mellin amplitude.

Fitzpatrick, A.Liam; /Stanford U., Phys. Dept.; Kaplan, Jared; /SLAC

2012-08-28

367

Planck Constraints on Holographic Dark Energy  

E-print Network

We perform a detailed investigation on the cosmological constraints on the holographic dark energy (HDE) model by using the Planck data. HDE can provide a good fit to Planck high-l (l>40) temperature power spectrum, while the discrepancy at l=20-40 found in LCDM remains unsolved in HDE. The Planck data alone can lead to strong and reliable constraint on the HDE parameter c. At 68% CL, we get c=0.508+-0.207 with Planck+WP+lensing, favoring the present phantom HDE at > 2sigma CL. Comparably, by using WMAP9 alone we cannot get interesting constraint on c. By combining Planck+WP with the BAO measurements from 6dFGS+SDSS DR7(R)+BOSS DR9, the H0 measurement from HST, the SNLS3 and Union2.1 SNIa data sets, we get 68% CL constraints c=0.484+-0.070, 0.474+-0.049, 0.594+-0.051 and 0.642+-0.066. Constraints can be improved by 2%-15% if we further add the Planck lensing data. Compared with the WMAP9 results, the Planck results reduce the error by 30%-60%, and prefer a phantom-like HDE at higher CL. We find no evident tension between Planck and BAO/HST. Especially, the strong correlation between Omegam h^3 and dark energy parameters is helpful in relieving the tension between Planck and HST. The residual chi^2_{Planck+WP+HST}-chi^2_{Planck+WP} is 7.8 in LCDM, and is reduced to 1.0 or 0.3 if we switch dark energy to the w model or the holographic model. We find SNLS3 is in tension with all other data sets; for Planck+WP, WMAP9 and BAO+HST, the corresponding Delta chi^2 is 6.4, 3.5 and 4.1, respectively. Comparably, Union2.1 is consistent with these data sets, but the combination Union2.1+BAO+HST is in tension with Planck+WP+lensing, corresponding to a Delta chi^2 8.6 (1.4% probability). Thus, it is not reasonable to perform an all-combined (CMB+SNIa+BAO+HST) analysis for HDE when using the Planck data. Our tightest self-consistent constraint is c=0.495+-0.039 obtained from Planck+WP+BAO+HST+lensing.

Miao Li; Xiao-Dong Li; Yin-Zhe Ma; Xin Zhang; Zhenhui Zhang

2013-10-01

368

NOTE Thyroid volume measurement in external beam radiotherapy patients using CT imaging: correlation with clinical and anthropometric characteristics  

NASA Astrophysics Data System (ADS)

The aim of this study is to define criteria for accurate representation of the thyroid in human models used to represent external beam radiotherapy (EBRT) patients and evaluate the relationship between the volume of this organ and clinical and anthropometric characteristics. From CT images, we segmented the thyroid gland and calculated its volume for a population of 188 EBRT patients of both sexes, with ages ranging from 1 to 89 years. To evaluate uncertainties linked to measured volumes, experimental studies on the Livermore anthropomorphic phantom were performed. For our population of EBRT patients, we observed that in children, thyroid volume increased rapidly with age, from about 3 cm3 at 2 years to about 16 cm3 at 20. In adults, the mean thyroid gland volume was 23.5 ± 9 cm3 for males and 17.5 ± 8 cm3 for females. According to anthropometric parameters, the best fit for children was obtained by modeling the log of thyroid volume as a linear function of body surface area (BSA) (p < 0.0001) and age (p = 0.04) and for adults, as a linear function of BSA (p < 0.0001) and gender (p = 0.01). This work enabled us to demonstrate that BSA was the best indicator of thyroid volume for both males and females. These results should be taken into account when modeling the volume of the thyroid in human models used to represent EBRT patients for dosimetry in retrospective studies of the relationship between the estimated dose to the thyroid and long-term follow-up data on EBRT patients.

Veres, C.; Garsi, J. P.; Rubino, C.; Pouzoulet, F.; Bidault, F.; Chavaudra, J.; Bridier, A.; Ricard, M.; Ferreira, I.; Lefkopoulos, D.; de Vathaire, F.; Diallo, I.

2010-11-01

369

Holographic properties of SiO2-nanoparticle dispersed PVA/AA photopolymer  

NASA Astrophysics Data System (ADS)

Hydrophilic SiO2-nanoperticals dispersed polyvinyl alcohol /acrylamide (PVA/AA) binder-based volume holographic recording photoloymers are fabricated. In this photopolymer, monomer-nanoparticle counter diffusion plays a fundamental and key role in hologram formation. The experimental results indicate that nearly 20% increase of diffraction efficiency together with refractive index modulation photopolymer films containing SiO2-nanoperticals contrast with traditional samples. The optimum concentration of SiO2-nanoperticals and the origin of diffraction efficiency enhancement are investigated. It is shown that the nanoparticles are uniformly dispersed in the sol-gel photopolymer and significantly influence on the grating formation. Additionally, the incorporation of inorganic nanoparticles into photopolymer leads to the substantive suppression of the volume shrinkage during holographic exposure.

Wang, Yan; Wang, Sulian; Li, Ruoping; Huang, Mingju

2009-08-01

370

Free volume of mixed cation borosilicate glass sealants elucidated by positron annihilation lifetime spectroscopy and its correlation with glass properties  

NASA Astrophysics Data System (ADS)

The role of La+3/Sr+2 ratios, which is varied from 0.08 to 5.09, on density, molar volume, packing fraction, free volume, thermal and electrical properties in strontium lanthanum aluminoborosilicate based glass sealants intended for solid oxide fuel cell (SOFC) applications is evaluated. The studies reveal expansion of the glass network evident from increasing molar volume and decreasing packing fraction of glasses with progressive La+3 substitutions. The molecular origin of these macroscopic structural features can be accounted for by the free volume parameters measured from positron annihilation lifetime spectroscopy (PALS). The La+3 induced expanded glass networks show increased number of subnanoscopic voids with larger sizes, as revealed from the ortho-positronium (o-Ps) lifetime and its intensity. A remarkably direct correspondence between the molar volume and fractional free volume trend is established with progressive La2O3 substitution in the glasses. The effect of these structural changes on the glass transition temperature, softening temperature, coefficient of thermal expansion, thermal stability as well as electrical conductivity has been studied.

Ojha, Prasanta K.; Rath, Sangram K.; Sharma, Sandeep K.; Sudarshan, Kathi; Pujari, Pradeep K.; Chongdar, Tapas K.; Gokhale, Nitin M.

2015-01-01

371

Dose-Volume Parameters of the Corpora Cavernosa Do Not Correlate With Erectile Dysfunction After External Beam Radiotherapy for Prostate Cancer: Results From a Dose-Escalation Trial  

SciTech Connect

Purpose: To analyze the correlation between dose-volume parameters of the corpora cavernosa and erectile dysfunction (ED) after external beam radiotherapy (EBRT) for prostate cancer. Methods and Materials: Between June 1997 and February 2003, a randomized dose-escalation trial comparing 68 Gy and 78 Gy was conducted. Patients at our institute were asked to participate in an additional part of the trial evaluating sexual function. After exclusion of patients with less than 2 years of follow-up, ED at baseline, or treatment with hormonal therapy, 96 patients were eligible. The proximal corpora cavernosa (crura), the superiormost 1-cm segment of the crura, and the penile bulb were contoured on the planning computed tomography scan and dose-volume parameters were calculated. Results: Two years after EBRT, 35 of the 96 patients had developed ED. No statistically significant correlations between ED 2 years after EBRT and dose-volume parameters of the crura, the superiormost 1-cm segment of the crura, or the penile bulb were found. The few patients using potency aids typically indicated to have ED. Conclusion: No correlation was found between ED after EBRT for prostate cancer and radiation dose to the crura or penile bulb. The present study is the largest study evaluating the correlation between ED and radiation dose to the corpora cavernosa after EBRT for prostate cancer. Until there is clear evidence that sparing the penile bulb or crura will reduce ED after EBRT, we advise to be careful in sparing these structures, especially when this involves reducing treatment margins.

Wielen, Gerard J. van der [Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands)], E-mail: g.vanderwielen@erasmusmc.nl; Hoogeman, Mischa S. [Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Dohle, Gert R. [Department of Urology, Erasmus MC, Rotterdam (Netherlands); Putten, Wim L.J. van [Department of Biostatistics, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Incrocci, Luca [Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam (Netherlands)

2008-07-01

372

Entanglement Tsunami: Universal Scaling in Holographic Thermalization  

E-print Network

We consider the time evolution of entanglement entropy after a global quench in a strongly coupled holographic system, whose subsequent equilibration is described in the gravity dual by the gravitational collapse of a thin ...

Liu, Hong

373

Holographic superconductivity in M-Theory  

E-print Network

Using seven-dimensional Sasaki-Einstein spaces we construct solutions of D=11 supergravity that are holographically dual to superconductors in three spacetime dimensions. Our numerical results indicate a new zero temperature solution dual to a quantum critical point.

Jerome P. Gauntlett; Julian Sonner; Toby Wiseman

2009-10-09

374

Holographic tachyon model of dark energy  

E-print Network

In this paper we consider a correspondence between the holographic dark energy density and tachyon energy density in FRW universe. Then we reconstruct the potential and the dynamics of the tachyon field which describe tachyon cosmology.

M R Setare

2007-09-11

375

Black hole and holographic dark energy  

E-print Network

We discuss the connection between black hole and holographic dark energy. We examine the issue of the equation of state (EOS) for holographic energy density as a candidate for the dark energy carefully. This is closely related to the EOS for black hole, because the holographic dark energy comes from the black hole energy density. In order to derive the EOS of a black hole, we may use its dual (quantum) systems. Finally, a regular black hole without the singularity is introduced to describe an accelerating universe inside the cosmological horizon. Inspired by this, we show that the holographic energy density with the cosmological horizon as the IR cutoff leads to the dark energy-dominated universe with $\\omega_{\\rm \\Lambda}=-1$.

Yun Soo Myung

2007-04-11

376

Digital holographic imaging of aquatic species  

E-print Network

The aim of this thesis is to design, develop and implement a digital holographic imaging (DHI) system, capable of capturing three-dimensional (3D) images of aquatic species. The images produced by this system are used in ...

Domínguez-Caballero, José Antonio

2006-01-01

377

Optimization methods in hierarchical holographic modeling  

NASA Astrophysics Data System (ADS)

The mathematical formulation of the hierarchical holographic modeling and solution methodology are explored. The hierarchical multiobjective optimization (HMO) methods that have been developed so far are useful mostly for the analysis of large scale systems which are controlled and managed by one planning group only. The mathematical representation of the HHM in a generic case and the effects of multiple decompositions on the decision vectors, multiobjective vectors and constraints vectors in three HHSubmodel cases are explored. The solution methodology of two hierarchical holographic submodels (HHS) is considered. Two algorithms, namely the Hierarchical Holographic Overlapping Coordination algorithm and the Hierarchical Holographic Feasible scheme are proposed for generating pareto optimal solutions of the HHSs. The coupling resource allocation problem faced by the upper level group, between two HHSs is addressed. The applicability of the HHM scheme to a hypothetical river basin related land resource management problem is explored.

Thadathil, J.

378

G-corrected holographic dark energy model  

E-print Network

Here we investigate the holographic dark energy model in the framework of FRW cosmology where the Newtonian gravitational constant,$G$, is varying with cosmic time. Using the complementary astronomical data which support the time dependency of $G$, the evolutionary treatment of EoS parameter and energy density of dark energy model are calculated in the presence of time variation of $G$. It has been shown that in this case, the phantom regime can be achieved at the present time. We also calculate the evolution of $G$- corrected deceleration parameter for holographic dark energy model and show that the dependency of $G$ on the comic time can influence on the transition epoch from decelerated expansion to the accelerated phase. Finally we perform the statefinder analysis for $G$- corrected holographic model and show that this model has a shorter distance from the observational point in $s-r$ plane compare with original holographic dark energy model.

Malekjani, M

2013-01-01

379

G-corrected holographic dark energy model  

NASA Astrophysics Data System (ADS)

Here we investigate the holographic dark energy model in the framework of FRW cosmology where the Newtonian gravitational constant, G, is varying with cosmic time. Using the complementary astronomical data which support the time dependency of G, the evolutionary treatment of EoS parameter and energy density of dark energy model are calculated in the presence of time variation of G. It has been shown that in this case, the phantom regime can be achieved at the present time. We also calculate the evolution of G-corrected deceleration parameter for holographic dark energy model and show that the dependency of G on the comic time can influence on the transition epoch from decelerated expansion to the accelerated phase. Finally we perform the statefinder analysis for G-corrected holographic model and show that this model has a shorter distance from the observational point in s- r plane compare with original holographic dark energy model.

Malekjani, M.; Honari-Jafarpour, M.

2013-08-01

380

Emergence in Holographic Scenarios for Gravity  

E-print Network

'Holographic' relations between theories have become an important theme in quantum gravity research. These relations entail that a theory without gravity is equivalent to a gravitational theory with an extra spatial dimension. The idea of holography was first proposed in 1993 by Gerard 't Hooft on the basis of his studies of evaporating black holes. Soon afterwards the holographic 'AdS/CFT' duality was introduced, which since has been intensively studied in the string theory community and beyond. Recently, Erik Verlinde has proposed that even Newton's law of gravitation can be related holographically to the 'thermodynamics of information' on screens. We discuss these scenarios, with special attention to the status of the holographic relation in them and to the question of whether they make gravity and spacetime emergent. We conclude that only Verlinde's scheme straightfowardly instantiates emergence. However, assuming a non-standard interpretation of AdS/CFT may create room for the emergence of spacetime and ...

Dieks, Dennis; de Haro, Sebastian

2015-01-01

381

Holographic Interferometry--A Laboratory Experiment.  

ERIC Educational Resources Information Center

Explains the problem of analyzing a phase object, separating the contribution due to thickness variations and that due to refractive index variations. Discusses the design of an interferometer and some applications. Provides diagrams and pictures of holographic images. (YP)

de Frutos, A. M.; de la Rosa, M. I.

1988-01-01

382

Modular digital holographic fringe data processing system  

NASA Technical Reports Server (NTRS)

A software architecture suitable for reducing holographic fringe data into useful engineering data is developed and tested. The results, along with a detailed description of the proposed architecture for a Modular Digital Fringe Analysis System, are presented.

Downward, J. G.; Vavra, P. C.; Schebor, F. S.; Vest, C. M.

1985-01-01

383

Changes in Hippocampal Volume are Correlated with Cell Loss but Not with Seizure Frequency in Two Chronic Models of Temporal Lobe Epilepsy  

PubMed Central

Kainic acid (KA) or pilocarpine (PILO) have been used in rats to model human temporal lobe epilepsy (TLE) but the distribution and severity of structural lesions between these two models may differ. Magnetic resonance imaging (MRI) studies have used quantitative measurements of hippocampal T2 (T2HP) relaxation time and volume, but simultaneous comparative results have not been reported yet. The aim of this study was to compare the MRI T2HP and volume with histological data and frequency of seizures in both models. KA- and PILO-treated rats were imaged with a 2?T MRI scanner. T2HP and volume values were correlated with the number of cells, mossy fiber sprouting, and spontaneous recurrent seizures (SRS) frequency over the 9?months following status epilepticus (SE). Compared to controls, KA-treated rats had unaltered T2HP, pronounced reduction in hippocampal volume and concomitant cell reduction in granule cell layer, CA1 and CA3 at 3?months post SE. In contrast, hippocampal volume was unchanged in PILO-treated animals despite detectable increased T2HP and cell loss in granule cell layer, CA1 and CA3. In the following 6?months, MRI hippocampal volume remained stable with increase of T2HP signal in the KA-treated group. The number of CA1 and CA3 cells was smaller than age-matched CTL group. In contrast, PILO group had MRI volumetric reduction accompanied by reduction in the number of CA1 and CA3 cells. In this group, T2HP signal was unaltered at 6 or 9?months after status. Reductions in the number of cells were not progressive in both models. Notably, the SRS frequency was higher in PILO than in the KA model. The volumetry data correlated well with tissue damage in the epileptic brain, suggesting that MRI may be useful for tracking longitudinal hippocampal changes, allowing the assessment of individual variability and disease progression. Our results indicate that the temporal changes in hippocampal morphology are distinct for both models of TLE and that these are not significantly correlated to the frequency of SRS. PMID:25071699

Polli, Roberson S.; Malheiros, Jackeline M.; dos Santos, Renan; Hamani, Clement; Longo, Beatriz M.; Tannús, Alberto; Mello, Luiz E.; Covolan, Luciene

2014-01-01

384

Holographic Superconductors in Horava-Lifshitz Gravity  

E-print Network

We consider holographic superconductors related to the Schwarzschild black hole in the low energy limit of Ho\\v{r}ava-Lifshitz spacetime. The non-relativistic electromagnetic and scalar fields are introduced to construct a holographic superconductor model in Ho\\v{r}ava-Lifshitz gravity and the results show that the $\\alpha_2$ term plays an important role, modifying the conductivity curve line by means of an attenuation the conductivity.

Kai Lin; Elcio Abdalla; Anzhong Wang

2014-06-18

385

Holographic Optical Elements as Scanning Lidar Telescopes  

NASA Technical Reports Server (NTRS)

We have investigated and developed the use of holographic optical elements (HOE) and holographic transmission gratings for scanning lidar telescopes. By rotating a flat HOE in its own plane with the focal spot on the rotation axis, a very simple and compact conical scanning telescope is possible. We developed and tested transmission and reflection HOES for use with the first three harmonics of Nd:YAG lasers, and designed, built, and tested two lidar systems based on this technology.

Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.

2003-01-01

386

Holographic Mutual Information at small separations  

E-print Network

The holographic mutual information for the small separation of two circles and two strips in 2+1 dimensional space-time is considered based on the known exact minimal surfaces spanning the boundaries on AdS4. The results suggest a universality for the leading term in the short-distance expansion of holographic mutual information. A conjecture for a similar result for d > 2 is also presented, as well as comments about the analogous expansion in conformal field theory.

Agon, Cesar A

2015-01-01

387

Holographic Mutual Information at small separations  

E-print Network

The holographic mutual information for the small separation of two circles and two strips in 2+1 dimensional space-time is considered based on the known exact minimal surfaces spanning the boundaries on AdS4. The results suggest a universality for the leading term in the short-distance expansion of holographic mutual information. A conjecture for a similar result for d > 2 is also presented, as well as comments about the analogous expansion in conformal field theory.

Cesar A. Agon; Howard J. Schnitzer

2015-02-10

388

Shift-multiplexed holographic memory using the two-lambda method  

Microsoft Academic Search

Shift multiplexing1,2 is a method for holographic storage that uses nonplanar reference beams. A volume hologram recorded with a spherical-wave refer- ence becomes Bragg mismatched when it is translated with respect to the readout beam. This effect can be used to multiplex holograms in the same recording medium.1,3 The required amount of translation d between holograms is called shift selectivity

George Barbastathis; Demetri Psaltis

1996-01-01

389

Radiologic-pathologic correlation of three-dimensional shear-wave elastographic findings in assessing the liver ablation volume after radiofrequency ablation  

PubMed Central

AIM: To evaluate the usefulness of three-dimensional (3D) shear-wave elastography (SWE) in assessing the liver ablation volume after radiofrequency (RF) ablation. METHODS: RF ablation was performed in vivo in 10 rat livers using a 15-gauge expandable RF needle. 3D SWE as well as B-mode ultrasound (US) were performed 15 min after ablation. The acquired 3D volume data were rendered as multislice images (interslice distance: 1.10 mm), and the estimated ablation volumes were calculated. The 3D SWE findings were compared against digitized photographs of gross pathological and histopathological specimens of the livers obtained in the same sectional planes as the 3D SWE multislice images. The ablation volumes were also estimated by gross pathological examination of the livers, and the results were then compared with those obtained by 3D SWE. RESULTS: In B-mode US images, the ablation zone appeared as a hypoechoic area with a peripheral hyperechoic rim; however, the findings were too indistinct to be useful for estimating the ablation area. 3D SWE depicted the ablation area and volume more clearly. In the images showing the largest ablation area, the mean kPa values of the peripheral rim, central zone, and non-ablated zone were 13.1 ± 1.5 kPa, 59.1 ± 21.9 kPa, and 4.3 ± 0.8 kPa, respectively. The ablation volumes depicted by 3D SWE correlated well with those estimated from gross pathological examination (r2 = 0.9305, P = 0.00001). The congestion and diapedesis of red blood cells observed in histopathological examination were greater in the peripheral rim of the ablation zone than in the central zone. CONCLUSION: 3D SWE outperforms B-mode US in delineating ablated areas in the liver and is therefore more reliable for spatially delineating thermal lesions created by RF ablation. PMID:25206291

Sugimoto, Katsutoshi; Oshiro, Hisashi; Ogawa, Saori; Honjo, Mitsuyoshi; Hara, Takeshi; Moriyasu, Fuminori

2014-01-01

390

History Of Holographic Display In Japan  

NASA Astrophysics Data System (ADS)

The first exhibition of holographic display was held at Seibu Museum of Art in Tokyo in 1975 and played a role of opening of the holographic era in Japan. This exhibition and the next big exhibition of holography held at Isetan department store 3 years later in 1978 were really epoch-making facts on holographic display in Japan. Since these two exhibitions, holographic display in Japan has come to attract attention of a lot of people to the new display media, holography. At that time, mass production technology of holograms had not been fully developed yet, and the hologram was so expensive that they were found only at the big event. Some companies and universities still continued research and development to have holograms get into practical applications of display media. Few years later, people became interested in 3-D displays and sometimes many peoples took an interest in holographic display, mainly mass produced embossed type holograms applied to the field of publications, book and magazine, etc. 3-D display booms occurred in the year of Tsukuba Science Expo'85 in 1985 and embossed type hologram became much popular. History of holographic display of Japan in terms of technical development and practical use on laser reconstruction hologram, rainbow hologram, multiplex hologram and lippmann hologram will be introduced.

Iwata, Fujio

1987-06-01

391

Correlation of Choroidal Thickness and Volume Measurements with Axial Length and Age Using Swept Source Optical Coherence Tomography and Optical Low-Coherence Reflectometry  

PubMed Central

Purpose. To report choroidal thickness and volume in healthy eyes using swept source optical coherence tomography (SS-OCT). Methods. A prospective observational study of 122 patients examined with swept source OCT (DRI-OCT, Topcon, Japan). In each eye, we performed 256 horizontal scans, 12?mm in length and centered on the fovea. We calculated choroidal thickness manually with a built-in caliper and automatically using DRI-OCT mapping software. Choroidal volume was also automatically calculated. We measured axial length with optical low-coherence reflectometry (Lenstar LS 900, Haag-Streit, Switzerland). Results. The choroid has focally increased thickness under the fovea. Choroid was thinnest in the outer nasal quadrant. In stepwise regression analysis, age was estimated as the most significant factor correlating with decreased choroidal thickness (F = 23.146, P < 0.001) followed by axial length (F = 4.902, P = 0.03). Refractive error was not statistically significant (F = 1.16, P = 0.28). Conclusions. SS-OCT is the first commercially available system that can automatically create choroidal thickness and volume maps. Choroidal thickness is increased at the fovea and is thinnest nasally. Age and axial length are critical for the estimation of choroidal thickness and volume. Choroidal measurements derived from SS-OCT images have potential value for objectively documenting disease-related choroidal thickness abnormalities and monitoring progressive changes over time. PMID:25013793

Michalewski, Janusz; Nawrocka, Zofia; Bednarski, Maciej; Nawrocki, Jerzy

2014-01-01

392

Cosmological constraints from the redshift dependence of the Alcock-Paczynski test and volume effect: galaxy two-point correlation function  

E-print Network

We propose a method using the redshift dependence of the Alcock-Paczynski (AP) test and volume effect to measure the cosmic expansion history. The galaxy two-point correlation function as a function of angle, $\\xi(\\mu)$, is measured at different redshifts. Assuming an incorrect cosmological model to convert galaxy redshifts to distances, the shape of $\\xi(\\mu)$ appears anisotropic due to the AP effect, and the amplitude shifted by the change in comoving volume. Due to the redshift dependence of the AP and volume effect, both the shape and amplitude of $\\xi(\\mu)$ exhibit redshift dependence. Similar to Li et.al (2014), we find the redshift-space distortions (RSD) caused by galaxy peculiar velocities, although significantly distorts $\\xi(\\mu)$, exhibit much less redshift evolution compared to the AP and volume effects. By focusing on the redshift dependence of $\\xi(\\mu)$, we can correctly recover the cosmological parameters despite the contamination of RSD. The method is tested by using the Horizon Run 3 N-body...

Li, Xiao-Dong; Sabiu, Cristiano G; Kim, Juhan

2015-01-01

393

Advantages of holographic optical tweezers  

NASA Astrophysics Data System (ADS)

In the last decade optical tweezers became an important tool in microbiology. However, the setup becomes very complex if more than one trap needs to be moved. Holographic tweezers offer a very simple and cost efficient way of manipulating several traps independently in all three dimensions with an accuracy of less 100 nm. No mechanically moving parts are used therefore making them less vulnerable to vibration. They use computer-generated holograms (CGHs) written into a spatial light modulator (SLM) to control the position of each trap in space and to manipulate their shape. The ability to change the shape of the optical trap makes it possible to adapt the light field to a specific particle shape or in the case of force measurements to adjust the trapping potential. Furthermore the SLM can be used to correct for aberrations within the optical setup.

Reicherter, Marcus; Liesener, Jan; Haist, Tobias; Tiziani, Hans J.

2003-10-01

394

Automatic analysis of holographic interferograms  

NASA Astrophysics Data System (ADS)

A technique for producing infinite fringe background holographic interferograms is described. A heat transfer study using fringes to represent isotherms investigated the temperature field and heat transfer distribution over several geometries in a wind tunnel. The fringes represented isotherms. The interferograms were investigated along scan lines that lay essentially perpendicular to the general orientation of the isotherms, and the fringe coordinates were extracted using either a bucket-bin technique or a gradient change algorithm. Results were compared with those of a Large Eddy Simulation, (LES). A compressible flow study investigated the influence of blade incidence upon the flow within low pressure transonic steam turbine blading. Here fringes represented isobars. To simplify the interferograms, a two-dimensional automatic fringe analysis system was devised, involving binarization of the fringe field, followed by detection and tracing of the fringe edges. Fringe coordinates than can by used to produce a map of the complete density distribution.

Hunter, J. C.

395

Holographic Dark Matter and Higgs  

E-print Network

We identify possible dark matter candidates within the class of strongly interacting models where electroweak symmetry breaking is triggered by a light composite Higgs boson. In these models, the Higgs boson emerges as a Holographic pseudo-goldstone boson, while dark matter can be identified as a fermionic composite state X^0, which is made stable through a conserved (``dark'') quantum number. An effective lagrangian description of both the Higgs and dark matter is proposed, that includes higher-dimensional operators suppressed by an scale \\Lambda_i. These operators will induce deviations from the standard Higgs properties that could be meassured at future colliders (LHC,ILC), and thus provide information on the dark matter scale. The dark matter X^0, is expected to have a mass of order O(TeV), which is in agreement with the values extracted from the cosmological bounds and the experimental searches for dark matter.

J. Lorenzo Diaz-Cruz

2007-11-04

396

Holographic Cosmology from BIonic Solutions  

E-print Network

In this paper, we will use a BIonic solution for analysing the holographic cosmology. A BIonic solution is a configuration of a D-brane and an anti-D-brane connected by a wormhole. A BIonic configuration can form due to a transition of fundamental black strings. After the BIon has formed, the wormhole in the BIon will act act as a channel for the energy to flow into the D3-brane. This will increase the degrees of freedom of the D3-brane causing inflation. The inflation will end when the wormhole gets annihilated. However, as the distance between the D3-brane and the anti-D3-brane reduces, tachyonic states get created. These tachyonic states will lead to the formation of a new wormhole. This new wormhole will again increasing the degrees of freedom on the D3-brane causing late time acceleration.

Sepehri, Alireza; Setare, Mohammad Reza; Ali, Ahmed Farag

2015-01-01

397

Holographic Cosmology from BIonic Solutions  

E-print Network

In this paper, we will use a BIonic solution for analysing the holographic cosmology. A BIonic solution is a configuration of a D-brane and an anti-D-brane connected by a wormhole. A BIonic configuration can form due to a transition of fundamental black strings. After the BIon has formed, the wormhole in the BIon will act act as a channel for the energy to flow into the D3-brane. This will increase the degrees of freedom of the D3-brane causing inflation. The inflation will end when the wormhole gets annihilated. However, as the distance between the D3-brane and the anti-D3-brane reduces, tachyonic states get created. These tachyonic states will lead to the formation of a new wormhole. This new wormhole will again increasing the degrees of freedom on the D3-brane causing late time acceleration.

Alireza Sepehri; Mir Faizal; Mohammad Reza Setare; Ahmed Farag Ali

2015-02-17

398

Pulsed lasers for holographic interferometry  

NASA Astrophysics Data System (ADS)

Optical holography has been successfully utilized for a wide variety of applications in such areas as structural analysis, flow visualization, biomechanics, and analysis of particle fields. Pulsed lasers capable of delivering multijoule pulses of holographic quality with pulse widths of the order of 10 ns play an important role in such applications where the phenomena under study are inherently transient or where it is difficult to isolate the experimental apparatus from ambient vibrations. This paper reviews the design, performance characteristics, and selection criteria for the two most popular pulsed lasers used in holography, ruby and frequency-doubled Nd:YAG lasers. In addition, two other lasers, alexandrite and CO2 lasers, which are not commonly used in this area but which offer great potential, are briefly discussed.

Pitlak, R. T.; Page, R.

1985-08-01

399

Casting Shadows on Holographic Reconstruction  

E-print Network

In the context of the AdS/CFT correspondence, we study several holographic probes that relate information about the bulk spacetime to CFT data. The best-known example is the relation between minimal surfaces in the bulk and entanglement entropy of a subregion in the CFT. Building on earlier work, we identify "shadows" in the bulk: regions that are not illuminated by any of the bulk probes we consider, in the sense that the bulk surfaces do not pass through these regions. We quantify the size of the shadow in the near horizon region of a black hole and in the vicinity of a sufficiently dense star. The existence of shadows motivates further study of the bulk-boundary dictionary in order to identify CFT quantities that encode information about the shadow regions in the bulk. We speculate on the interpretation of our results from a dual field theory perspective.

Freivogel, Ben; Kabir, Laurens; Mosk, Benjamin; Yang, I-Sheng

2014-01-01

400

Excited Baryons in Holographic QCD  

SciTech Connect

The light-front holographic QCD approach is used to describe baryon spectroscopy and the systematics of nucleon transition form factors. Baryon spectroscopy and the excitation dynamics of nucleon resonances encoded in the nucleon transition form factors can provide fundamental insight into the strong-coupling dynamics of QCD. The transition from the hard-scattering perturbative domain to the non-perturbative region is sensitive to the detailed dynamics of confined quarks and gluons. Computations of such phenomena from first principles in QCD are clearly very challenging. The most successful theoretical approach thus far has been to quantize QCD on discrete lattices in Euclidean space-time; however, dynamical observables in Minkowski space-time, such as the time-like hadronic form factors are not amenable to Euclidean numerical lattice computations.

de Teramond, Guy F.; /Costa Rica U.; Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins

2011-11-08

401

Character process model for semen volume in AI rams: evaluation of correlation structures for long and short-term environmental effects  

PubMed Central

The objective of this study was to build a character process model taking into account serial correlations for the analysis of repeated measurements of semen volume in AI rams. For each ram, measurements were repeated within and across years. Therefore, we considered a model including three environmental effects: the long-term environmental effect, which is a random year* subject effect, the short-term environmental effect, which is a random within year subject* collection effect, and the classical measurement error. We used a four-step approach to build the model. The first step explored graphically the serial correlations. The second step compared four models with different correlation structures for the short-term environmental effect. We selected fixed effects in the third step. In the fourth step, we compared four correlation structures for the long-term environmental effect. The model, which fitted best the data, used a spatial power correlation structure for the short-term environmental effect and a first order autoregressive process for the long-term environmental effect. The heritability estimate was 0.27 (0.04), the within year repeatability decreased from 0.56 to 0.44 and the repeatability across years decreased from 0.43 to 0.37. PMID:17212948

David, Ingrid; Bodin, Loys; Lagriffoul, Gilles; Manfredi, Eduardo; Robert-Granié, Christèle

2007-01-01

402

Novel computational approach for studying ph effects, excluded volume and ion-ion correlations in electrical double layers around polyelectrolytes and nanoparticles  

NASA Astrophysics Data System (ADS)

Highly charged cylindrical and spherical objects (macroions) are probably the simplest structures for modeling nucleic acids, proteins and nanoparticles. Their ubiquitous presence within biophysical systems ensures that Coulomb forces are among the most important interactions that regulate the behavior of these systems. In these systems, ions position themselves in a strongly correlated manner near the surface of a macroion and form electrical double layers (EDLs). These EDLs play an important role in many biophysical and biochemical processes. For instance, the macroion's net charge can change due to the binding of many multivalent ions to its surface. Thus, proper description of EDLs near the surface of a macroion may reveal a counter-intuitive charge inversion behavior, which can generate attraction between like-charged objects. This is relevant for the variety of fields such as self-assembly of DNA and RNA folding, as well as for protein aggregation and neurodegenerative diseases. Certainly, the key factors that contribute to these phenomena cannot be properly understood without an accurate solvation model. With recent advancements in computer technologies, the possibility to use computational tools for fundamental understanding of the role of EDLs around biomolecules and nanoparticles on their physical and chemical properties is becoming more feasible. Establishing the impact of the excluded volume and ion-ion correlations, ionic strength and pH of the electrolyte on the EDL around biomolecules and nanoparticles, and how changes in these properties consequently affect the Zeta potential and surface charge density are still not well understood. Thus, modeling and understanding the role of these properties on EDLs will provide more insights on the stability, adsorption, binding and function of biomolecules and nanoparticles. Existing mean-field theories such as Poisson Boltzmann (PB) often neglect the ion-ion correlations, solvent and ion excluded volume effects, which are important details for proper description of EDL properties. In this thesis, we implement an efficient and accurate classical solvation density functional theory (CDSFT) for EDLs of spherical macroions and cylindrical polyelectrolytes embedded in aqueous electrolytes. This approach extends the capabilities of mean field approximations by taking into account electrostatic ion-ion correlations, size asymmetry and excluded volume effects without compromising the computational cost. We apply the computational tool to study the structural and thermodynamic properties of the ionic atmosphere around B-DNA and spherical nanoparticles. We demonstrate that the presence of solvent molecules at experimental concentration and size values has a significant impact on the layering of ions. This layering directly influences the integrated charge and mean electrostatic potential in the diffuse region of the spherical electrical double layer (SEDL) and have a noticeable impact on the behavior of zeta potential (ZP). Recently, we have extended the aforementioned CSDFT to account for the charge-regulated mechanisms of the macroion surface on the structural and thermodynamic properties of spherical EDLs. In the approach, the CSDFT is combined with a surface complexation model to account for ion correlation and excluded volume effects on the surface titration of spherical macroions. We apply the proposed computational approach to describe the role that the ion size and solvent excluded volume play on the surface titration properties of silica nanoparticles. We analyze the effects of the nanoparticle size, pH and salt concentration of the aqueous solution on the nanoparticle's surface charge and zeta potential. The results reveal that surface charge density and zeta potential significantly depend on excluded volume and ion-ion correlation effects as well as on pH for monovalent ion species at high salt concentrations. Overall, our results are in good agreement with Monte Carlo simulations and available experimental data. We discuss future directions of this work, which incl

Ovanesyan, Zaven

403

Three-dimensional placental volume and mean grey value: Normal ranges in a Turkish population and correlation with maternal serum biochemistry and Doppler parameters.  

PubMed

The aim of this study is to evaluate the relationship between three-dimensional (3D) ultrasound measurements of placenta at 11-13(6) weeks' gestation and maternal serum levels of pregnancy associated plasma protein-A (PAPP-A), free beta human chorionic gonadotrophin (f?hCG), Doppler parameters in early pregnancy. This prospective study consisted of 334 singleton pregnancies at 11-13(6) weeks' gestation. Placental volume and placental volumetric mean grey values were evaluated. The placental volume (cm(3)) was analysed using the Virtual Organ Computer-aided AnaLysis (VOCAL) imaging program and 3D histogram was used to calculate the volumetric mean grey value (%). Mean maternal age was 28.35 ± 7.55. Mean gestational age was 12.29 ± 0.68 weeks. Placental volume was 77.04 ± 35.74 cm(3). Mean grey value of the placenta was 34.38 ± 8.02%. Correlation analysis revealed that placental volume was significantly correlated with the crown-rump length (r = 0.173, p = 0.002), gestational week (r = 0.116, p = 0.036), ductus venosus pulsatility index (r = -0.101, p = 0.04) and maternal weight (r = 0.099, p = 0.037). There was a significant relation between the mean grey value of the placenta and maternal age (r = 0.131, p = 0.02), nuchal translucency (r = -0.109, p = 0.048), PAPP-A (r = 0.108, p = 0.04) and f?hCG (r = 0.104, p = 0.042). Volumetry of the placenta can be carried out with a high percentage of 1st trimester pregnancies. Volumetry during the 1st trimester could be helpful because of the less advanced state of placentation. This examination is easy to perform and the measurements can be acquired correctly and quickly. PMID:25254419

Pala, H G; Artunc Ulkumen, B; Uyar, Y; Koyuncu, F M; Bulbul Baytur, Y

2014-09-25

404

Stability of the holographic description of the Universe  

E-print Network

We investigate the stability of the holographic description of the universe. By treating the perturbation globally, we discover that this description is stable, which is support for the holographic description of the universe.

Peng Huang; Yong-chang Huang

2013-04-01

405

Tracking the Roots of Reading Ability: White Matter Volume and Integrity Correlate with Phonological Awareness in Prereading and Early-Reading Kindergarten Children  

PubMed Central

Developmental dyslexia, an unexplained difficulty in learning to read, has been associated with alterations in white matter organization as measured by diffusion-weighted imaging. It is unknown, however, whether these differences in structural connectivity are related to the cause of dyslexia or if they are consequences of reading difficulty (e.g., less reading experience or compensatory brain organization). Here, in 40 kindergartners who had received little or no reading instruction, we examined the relation between behavioral predictors of dyslexia and white matter organization in left arcuate fasciculus, inferior longitudinal fasciculus, and the parietal portion of the superior longitudinal fasciculus using probabilistic tractography. Higher composite phonological awareness scores were significantly and positively correlated with the volume of the arcuate fasciculus, but not with other tracts. Two other behavioral predictors of dyslexia, rapid naming and letter knowledge, did not correlate with volumes or diffusion values in these tracts. The volume and fractional anisotropy of the left arcuate showed a particularly strong positive correlation with a phoneme blending test. Whole-brain regressions of behavioral scores with diffusion measures confirmed the unique relation between phonological awareness and the left arcuate. These findings indicate that the left arcuate fasciculus, which connects anterior and posterior language regions of the human brain and which has been previously associated with reading ability in older individuals, is already smaller and has less integrity in kindergartners who are at risk for dyslexia because of poor phonological awareness. These findings suggest a structural basis of behavioral risk for dyslexia that predates reading instruction. PMID:23946384

Osher, David E.; Beach, Sara D.; Cyr, Abigail B.; Ozernov-Palchik, Ola; Yendiki, Anastasia; Fischl, Bruce; Gaab, Nadine; Gabrieli, John D.E.

2013-01-01

406

Quantitative 3D strain analysis in analogue experiments simulating tectonic deformation: Integration of X-ray computed tomography and digital volume correlation techniques  

NASA Astrophysics Data System (ADS)

The combination of scaled analogue experiments, material mechanics, X-ray computed tomography (XRCT) and Digital Volume Correlation techniques (DVC) is a powerful new tool not only to examine the 3 dimensional structure and kinematic evolution of complex deformation structures in scaled analogue experiments, but also to fully quantify their spatial strain distribution and complete strain history. Digital image correlation (DIC) is an important advance in quantitative physical modelling and helps to understand non-linear deformation processes. Optical non-intrusive (DIC) techniques enable the quantification of localised and distributed deformation in analogue experiments based either on images taken through transparent sidewalls (2D DIC) or on surface views (3D DIC). X-ray computed tomography (XRCT) analysis permits the non-destructive visualisation of the internal structure and kinematic evolution of scaled analogue experiments simulating tectonic evolution of complex geological structures. The combination of XRCT sectional image data of analogue experiments with 2D DIC only allows quantification of 2D displacement and strain components in section direction. This completely omits the potential of CT experiments for full 3D strain analysis of complex, non-cylindrical deformation structures. In this study, we apply digital volume correlation (DVC) techniques on XRCT scan data of "solid" analogue experiments to fully quantify the internal displacement and strain in 3 dimensions over time. Our first results indicate that the application of DVC techniques on XRCT volume data can successfully be used to quantify the 3D spatial and temporal strain patterns inside analogue experiments. We demonstrate the potential of combining DVC techniques and XRCT volume imaging for 3D strain analysis of a contractional experiment simulating the development of a non-cylindrical pop-up structure. Furthermore, we discuss various options for optimisation of granular materials, pattern generation, and data acquisition for increased resolution and accuracy of the strain results. Three-dimensional strain analysis of analogue models is of particular interest for geological and seismic interpretations of complex, non-cylindrical geological structures. The volume strain data enable the analysis of the large-scale and small-scale strain history of geological structures.

Adam, J.; Klinkmüller, M.; Schreurs, G.; Wieneke, B.

2013-10-01

407

The Compact and Inexpensive "Arrowhead" Setup for Holographic Interferometry  

ERIC Educational Resources Information Center

Hologram recording and holographic interferometry are intrinsically sensitive to phase changes, and therefore both are easily perturbed by minuscule optical path perturbations. It is therefore very convenient to bank on holographic setups with a reduced number of optical components. Here we present a compact off-axis holographic setup that…

Ladera, Celso L.; Donoso, Guillermo

2011-01-01

408

Future of photorefractive based holographic 3D display  

Microsoft Academic Search

The very first demonstration of our refreshable holographic display based on photorefractive polymer was published in Nature early 20081. Based on the unique properties of a new organic photorefractive material and the holographic stereography technique, this display addressed a gap between large static holograms printed in permanent media (photopolymers) and small real time holographic systems like the MIT holovideo. Applications

P.-A. Blanche; A. Bablumian; R. Voorakaranam; C. Christenson; D. Lemieux; J. Thomas; R. A. Norwood; M. Yamamoto; N. Peyghambarian

2010-01-01

409

Holographic Dark Energy Model with Modified Variable Chaplygin Gas  

E-print Network

In this letter we consider a correspondence between holographic dark energy and variable modified Chaplygin gas to obtain a holographic dark energy model of the universe. The corresponding potential of the scalar field has been reconstructed which describes the modified variable Chaplygin gas. The stability of the holographic dark energy in this case is also discussed.

B. C. Paul

2010-06-17

410

Brain Tissue Volumes and Perfusion Change with the Number of Optic Neuritis Attacks in Relapsing Neuromyelitis Optica: A Voxel-Based Correlation Study  

PubMed Central

Recent neuroimaging studies show that brain abnormalities in neuromyelitis optica (NMO) are more frequent than earlier described. Yet, more research considering multiple aspects of NMO is necessary to better understand these abnormalities. A clinical feature of relapsing NMO (RNMO) is that the incremental disability is attack-related. Therefore, association between the attack-related process and neuroimaging might be expected. On the other hand, the immunopathological analysis of NMO lesions has suggested that CNS microvasculature could be an early disease target, which could alter brain perfusion. Brain tissue volume changes accompanying perfusion alteration could also be expected throughout the attack-related process. The aim of this study was to investigate in RNMO patients, by voxel-based correlation analysis, the assumed associations between regional brain white (WMV) and grey matter volumes (GMV) and/or perfusion on one side, and the number of optic neuritis (ON) attacks, myelitis attacks and/or total attacks on the other side. For this purpose, high resolution T1-weighted MRI and perfusion SPECT imaging were obtained in 15 RNMO patients. The results showed negative regional correlations of WMV, GMV and perfusion with the number of ON attacks, involving important components of the visual system, which could be relevant for the comprehension of incremental visual disability in RNMO. We also found positive regional correlation of perfusion with the number of ON attacks, mostly overlapping the brain area where the WMV showed negative correlation. This provides evidence that brain microvasculature is an early disease target and suggests that perfusion alteration could be important in the development of brain structural abnormalities in RNMO. PMID:23824339

Sánchez-Catasús, Carlos A.; Cabrera-Gomez, José; Almaguer Melián, William; Giroud Benítez, José Luis; Rodríguez Rojas, Rafael; Bayard, Jorge Bosch; Galán, Lídice; Sánchez, Reinaldo Galvizu; Fuentes, Nancy Pavón; Valdes-Sosa, Pedro

2013-01-01

411

Event-by-event analysis of baryon-strangeness correlations: Pinning down the critical temperature and volume of quark-gluon-plasma formation  

SciTech Connect

The recently proposed baryon-strangeness correlation (C{sub BS}) is studied with a string-hadronic transport model (UrQMD) for various energies from E{sub lab}=4A GeV to {radical}(s)=200A GeV. It is shown that rescattering among secondaries cannot mimic the predicted correlation pattern expected for a quark-gluon-plasma. However, we find a strong increase of the C{sub BS} correlation function with decreasing collision energy for p+p and Au+Au and/or Pb+Pb reactions. For Au+Au reactions at the top BNL Relativistic Heavy Ion Collider energy ({radical}(s)=200A GeV), the C{sub BS} correlation is constant for all centralities and compatible with the p+p result. With increasing width of the rapidity window, C{sub BS} follows roughly the shape of the baryon rapidity distribution. We suggest studying the energy and centrality dependence of C{sub BS} to gain information on the onset of the deconfinement transition in temperature and volume.

Haussler, Stephane [Frankfurt Institute for Advanced Studies (FIAS), Johann Wolfgang Goethe Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt (Germany); Stoecker, Horst [Frankfurt Institute for Advanced Studies (FIAS), Johann Wolfgang Goethe Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt (Germany); Institut fuer Theoretische Physik, Johann Wolfgang Goethe Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt (Germany); Bleicher, Marcus [Institut fuer Theoretische Physik, Johann Wolfgang Goethe Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt (Germany)

2006-02-15

412

Instanton bags, high density holographic QCD, and chiral symmetry restoration  

NASA Astrophysics Data System (ADS)

We describe the simplest example of an instanton bag in Euclidean space. It consists of a monopole wall and a Kaluza-Klein monopole wall, lifted to one higher dimension, trapping the instanton charge in the middle. This object has finite instanton density in a three-dimensional volume. Baryon physics in holographic QCD models gets translated into a multi-instanton problem in the bulk, and a state with a high density baryonic charge consists of a nondiluted multi-instanton solution. The instanton bag is a good candidate for this high-density state. We compute its parameters via moduli stabilization. Chiral symmetry restoration is exhibited by this state, and it is a direct consequence of its nondiluted features.

Bolognesi, S.

2014-11-01

413

Instanton Bags, High Density Holographic QCD and Chiral Symmetry Restoration  

E-print Network

We describe the simplest example of an instanton bag in Euclidean space. It consists of a monopole wall and a Kaluza-Klein monopole wall, lifted to one higher dimension, trapping the instanton charge in the middle. This object has finite instanton density in a three-dimensional volume. Baryon physics in holographic QCD models gets translated into a multi-instanton problem in the bulk, and a state with a high density baryonic charge consists of a non-diluted multi-instanton solution. The instanton bag is a good candidate for this high-density state. We compute its parameters via moduli stabilization. Chiral symmetry restoration is exhibited by this state, and it is a direct consequence of its non-diluted features.

S. Bolognesi

2014-10-16

414

Holographic memory module with ultra-high capacity and throughput  

SciTech Connect

High capacity, high transfer rate, random access memory systems are needed to archive and distribute the tremendous volume of digital information being generated, for example, the human genome mapping and online libraries. The development of multi-gigabit per second networks underscores the need for next-generation archival memory systems. During Phase I we conducted the theoretical analysis and accomplished experimental tests that validated the key aspects of the ultra-high density holographic data storage module with high transfer rate. We also inspected the secure nature of the encoding method and estimated the performance of full-scale system. Two basic architectures were considered, allowing for reversible compact solid-state configuration with limited capacity, and very large capacity write once read many memory system.

Vladimir A. Markov, Ph.D.

2000-06-04

415

Multiplexed holographic memory by use of fiber bundle referencing  

NASA Astrophysics Data System (ADS)

We propose a volume holographic storage technique, in which a fiber bundle is used to guide the reference beam. Multiplexing is implemented by changing the incident direction of the laser beam upon the fiber bundle in the reference arm. In the technique, we make the system more compact by using a wedge prism to change the direction of the laser beam. This method has a large accessible angular scanning range and a large geometric storage bandwidth. Multiple images are stored in a LiNbO3:Fe crystal with an angular separation of 0.05° between successive holograms using a wedge prism with a deviation angle of 8°. This method is useful as a new image storage technique because of its compactness and simplicity.

Zhang, Jiasen; Aruga, Tadashi

2005-04-01

416

Hybrid Catadioptric System for Holographic and Disk Application  

NASA Astrophysics Data System (ADS)

In this paper, we reveal a new device for use as an optical data storage system. The system is made up of Cassegrain-like structures. The volume (35× 20× 20 mm3) of the system is the size of a pickup head used in conventional optical storage. It has compatibility with several conventional optical disk technologies. Namely, the system provides a platform for integration with compact disc (CD), digital versatile disc (DVD), Blu-ray disc (BD) and holographic systems. The full width half maximums (FWHMs) of the spot size for a CD have been measured in this system and are 0.98 and 0.95 ?m in the tangential and radial directions, respectively.

Lan, Yung-Sung; Tien, Chung-Hao

2007-06-01

417

Holographic Operator Mixing and Quasinormal Modes on the Brane  

E-print Network

We provide a framework for calculating holographic Green's functions from general bilinear actions and fields obeying coupled differential equations in the bulk. The matrix-valued spectral function is shown to be independent of the radial bulk coordinate. Applying this framework we improve the analysis of fluctuations in the D3/D7 system at finite baryon density, where the longitudinal perturbations of the world-volume gauge field couple to the scalar fluctuations of the brane embedding. We compute the spectral function and show how its properties are related to the quasinormal mode spectrum. We study the crossover from the hydrodynamic diffusive to the reactive regime and the movement of quasinormal modes as functions of temperature and density. We also compute their dispersion relations and find that they asymptote to the lightcone for large momenta.

Kaminski, Matthias; Mas, Javier; Shock, Jonathan P; Tarrio, Javier

2009-01-01

418

Holographic Operator Mixing and Quasinormal Modes on the Brane  

E-print Network

We provide a framework for calculating holographic Green's functions from general bilinear actions and fields obeying coupled differential equations in the bulk. The matrix-valued spectral function is shown to be independent of the radial bulk coordinate. Applying this framework we improve the analysis of fluctuations in the D3/D7 system at finite baryon density, where the longitudinal perturbations of the world-volume gauge field couple to the scalar fluctuations of the brane embedding. We compute the spectral function and show how its properties are related to the quasinormal mode spectrum. We study the crossover from the hydrodynamic diffusive to the reactive regime and the movement of quasinormal modes as functions of temperature and density. We also compute their dispersion relations and find that they asymptote to the lightcone for large momenta.

Matthias Kaminski; Karl Landsteiner; Javier Mas; Jonathan P. Shock; Javier Tarrio

2009-11-18

419

Wavefront analysis and optimization from conventional liquid crystal displays for low-cost holographic optical tweezers and digital holographic microscopy  

Microsoft Academic Search

In different study fields the manipulation and imaging of micro-sized particles is essential. The use of holographic optical tweezers (HOT) and digital holographic microscopy (DHM) facilitates this task in a non-mechanical way by providing the proper computer generated hologram and the required amount of light. Electrically addressed spatial light modulators (EASLM) found in holographic optical tweezers are typically of the

Andreas Weber; Valentin Ortega Clavero; Werner Schröder

2011-01-01

420

Phase structures of holographic screen thermodynamics  

NASA Astrophysics Data System (ADS)

Holographic screens are the generalization of the event horizon of a black hole in entropic force scheme, which are defined by setting Newton potential ? constant, i.e. e2? = c = const. We demonstrate that the integrated first law of thermodynamics is equivalent to the (r-r) component of Einstein equations, so that we strengthen the correspondence between thermodynamics and gravity. We show that there are not only the first law of thermodynamics, but also kinds of phase transitions of holographic screens. These phase transitions are characterized by the discontinuity of their heat capacities. In (n+1)-dimensional Reissner-Nordström-anti-de Sitter (RN-AdS) spacetime, we analyze three kinds of phase transitions, which are of the holographic screens with Q = 0 (charge), constant ? (electrostatic potential) and nonzero constant Q. In the Q = 0 case, only the holographic screens with 0?c<1 can undergo phase transition. In the constant ? case, the constraints become as 0<= c+16˜ {? }2? 2<1, where ˜ {? } is a dimensional-dependent parameter. By verifying the Ehrenfest equations, we show that the phase transitions in this case are all second order phase transitions. In the constant Q case, there might be two, or one, or no phase transitions of holographic screens, depending on the values of Q and c.

Jiang, Wei-Jian; Chen, Yi-Xin; Li, Jian-Long

2014-07-01

421

Plasma fibrin D-dimer levels correlate with tumour volume, progression rate and survival in patients with metastatic breast cancer  

PubMed Central

Plasma levels of D-dimer are elevated in cancer patients. Activation of the extrinsic coagulation system and the fibrinolytic cascade within a tumour is thought to be related with growth, invasion and metastasis. We have investigated the relationship between these markers of fibrin metabolism, standard clinicopathological variables and serum levels of angiogenic cytokines in three cohorts: group A (n=30) consisted of 30 healthy female volunteers, group B (n=23) of consecutive patients with operable breast cancer and group C (n=84) of patients with untreated or progressive metastatic breast cancer. Plasma D-dimers, fibrinogen, IL-6, vascular endothelial growth factor and calculated vascular endothelial growth factor load in platelets are clearly increased in patients with breast cancer. D-dimers were increased in nearly 89% of patients with progressive metastatic disease. The level of D-dimers was positively correlated with tumour load (P<0.0001), number of metastatic sites (P=0.002), progression kinetics (P<0.0001) and the cytokines related to angiogenesis: serum vascular endothelial growth factor (P=0.0016, Spearman correlation=0.285), calculated vascular endothelial growth factor load in platelets (P<0.0001, Spearman correlation=0.37) and serum interleukin-6 (P<0.0001, Spearman correlation=0.59). Similarly increased D-dimer levels were positively correlated with increased fibrinogen levels (P<0.0001, Spearman correlation=0.38). The association between markers of fibrin degradation in patients with progressive breast cancer suggests that the D-dimer level is a clinically important marker for progression and points towards a relation between haemostasis and tumour progression. A role of interleukin-6, by influencing both angiogenesis and haemostasis, is suggested by these observations. British Journal of Cancer (2002) 86, 389–395. DOI: 10.1038/sj/bjc/6600069 www.bjcancer.com © 2002 The Cancer Research Campaign PMID:11875705

Dirix, L Y; Salgado, R; Weytjens, R; Colpaert, C; Benoy, I; Huget, P; van Dam, P; Prové, A; Lemmens, J; Vermeulen, P

2002-01-01

422

Correlation of Stroke Volume Measurement between Sonosite Portable Echocardiogram and Edwards Flotrac Sensor-Vigileo Monitor in an Intensive Care Unit  

PubMed Central

Purpose Stroke volume (SV) is a parameter that is being recognized as an endpoint in fluid resuscitation algorithms. Its role is now being realized as an important variable in hemodynamic assessment in various clinical scenarios such as septic and cardiogenic shocks. Direct measurement of stroke volume (SV) and its novel corollary, stroke volume variation (SVV) derived by proprietary software, are preferred over mean cardiac output (CO) measurements because they render a more accurate reflection of hemodynamic status independent of heart rate. Flotrac-Vigileo monitor (FTV) (Edwards Lifesciences, Irvine, CA, USA) is a system that uses a complex algorithm analyzing arterial waveform to calculate SV, SVV, and CO. We assessed the feasibility of obtaining SV measurements with a portable echocardiogram and validated its accuracy with the FTV system in mechanically ventilated patients in our intensive care unit (ICU). Furthermore, we emphasized the importance of hemodynamic measurements and familiarity with critical care echocardiography for the intensivists. Methods Ten patients who were on mechanical ventilation were studied. A femoral arterial line was connected to the FTV system monitoring SV and CO. A portable echocardiogram (M-Turbo; Sonosite, Bothell, WA) was used to measure SV. CO was calculated by multiplying SV by heart rate. No patient had arrhythmia. We used biplane Simpson’s method of discs to calculate SV in which subtraction of end-systolic volume from end-diastolic volume yields the SV. Results The comparison of simultaneous SV and CO measurements by echocardiography with FTV showed a strong correlation between the 2. (For SV, y = 0.9545x + 3.3, R2 = 0.98 and for CO, y = 0.9104x + 7.7074, R2 = 0.97). Conclusions In our small cohort, the SV and CO measured by a portable echocardiogram (Sonosite M-Turbo) appears to be closely correlated with their respective values measured by FTV. Portable echocardiography is a reliable noninvasive tool for the hemodynamic assessment of the critically ill. Its results need further validation with gold standard measures in a larger cohort of patients. However, our results suggest portable echocardiography could be an attractive tool in assessment of different hemodynamic scenarios in the critically ill. PMID:24052694

Behnia, Mehrdad; Powell, Sherry; Fallen, Linda; Tamaddon, Houman; Behnia, Masud

2013-01-01

423

Volume hologram multiplexing in dye-doped jelly-like gelatin  

Microsoft Academic Search

A thick-layer selfdeveloping photosensitive medium - dye-doped jelly-like gelatin was earlier proposed and investigated by us. It provides optical recording of the stationary volume phase gratings with high values of diffraction efficiency and angular selectivity. For a wide range of scientific and technical applications including holographic data storage, holographic optical elements, photonic crystals etc. multiplexed volume holograms are required. In

T. Sh. Efendiev; V. M. Katarkevich; A. N. Rubinov

2009-01-01

424

Holographic techniques applied to the solution of aerospace problems  

NASA Technical Reports Server (NTRS)

The use of conventional holographic methods including: (1) routine time-average holographic vibration analysis for determining mode shapes and location of cracks and disbonds, and (2) standard double-exposure holographic interferometry for measuring small displacements and locating flaws is described. Advances in holographic applications and techniques, including real-time motion-picture vibration analysis, contour holography, bleaching to increase diffraction efficiency, and a method for determining holographic system performance, are also presented. A description is given of anticipated future applications of holography such as computer synthesis and redesign of engine components, pulsed ruby holography for flow visualization, and online quality assurance inspection techniques.

Way, F. C.

1973-01-01

425

The underlying anatomical correlates of long-term meditation: Larger hippocampal and frontal volumes of gray matter  

E-print Network

The underlying anatomical correlates of long-term meditation: Larger hippocampal and frontal: Thalamus Orbital Hippocampus MRI Plasticity VBM Although the systematic study of meditation is still in its infancy, research has provided evidence for meditation-induced improvements in psychological

Gaser, Christian

426

On the Son-Yamamoto relation in the soft-wall holographic model of QCD  

NASA Astrophysics Data System (ADS)

We study the vertex function of two vector and one axial-vector operators in the soft-wall holographic model of QCD. In particular, we discuss the possible relation, introduced by Son and Yamamoto, between one of the structure functions, wT, describing such a vertex when one of the two vector currents represents an on-shell soft photon and the two-point ??VV-??AA correlator.

Nicotri, Stefano

2012-10-01

427

Holographic bulk viscosity: GPR vs EO  

E-print Network

Recently Eling and Oz (EO) proposed a formula for the holographic bulk viscosity, in arXiv:1103.1657, derived from the null horizon focusing equation. This formula seems different from that obtained earlier by Gubser, Pufu and Rocha (GPR) in arXiv:0806.0407 calculated from the IR limit of the two-point function of the trace of the stress tensor. The two were shown to agree only for some simple scaling cases. We point out that the two formulae agree in two non-trivial holographic theories describing RG flows. The first is the strongly coupled N=2* gauge theory plasma. The second is the semi-phenomenological model of Improved Holographic QCD.

Buchel, Alex; Kiritsis, Elias

2011-01-01

428

Holographic bulk viscosity: GPR vs EO  

E-print Network

Recently Eling and Oz (EO) proposed a formula for the holographic bulk viscosity, in arXiv:1103.1657, derived from the null horizon focusing equation. This formula seems different from that obtained earlier by Gubser, Pufu and Rocha (GPR) in arXiv:0806.0407 calculated from the IR limit of the two-point function of the trace of the stress tensor. The two were shown to agree only for some simple scaling cases. We point out that the two formulae agree in two non-trivial holographic theories describing RG flows. The first is the strongly coupled N=2* gauge theory plasma. The second is the semi-phenomenological model of Improved Holographic QCD.

Alex Buchel; Umut Gursoy; Elias Kiritsis

2011-04-11

429

Exact holographic mapping in free fermion systems  

E-print Network

In this paper, we shall perform a detailed analysis of the Exact Holographic Mapping first introduced in arXiv:1309.6282, which was proposed as an explicit example of holographic duality between quantum many-body systems and gravitational theories. We obtain analytic results for free-fermion systems that not only confirm previous numerical results, but also elucidate the exact relationships between the various physical properties of the bulk and boundary systems. Our analytic results allow us to study the asymptotic properties that are difficult to probe numerically, such as the near horizon regime of the black hole geometry. We shall also explore a few interesting but hitherto unexplored bulk geometries, such as that corresponding to a boundary critical fermion with nontrivial dynamic critical exponent. Our analytic framework also allows us to study the holographic mapping of some of these boundary theories in dimensions 2+1 or higher.

Lee, Ching Hua

2015-01-01

430

Exact holographic mapping in free fermion systems  

E-print Network

In this paper, we shall perform a detailed analysis of the Exact Holographic Mapping first introduced in arXiv:1309.6282, which was proposed as an explicit example of holographic duality between quantum many-body systems and gravitational theories. We obtain analytic results for free-fermion systems that not only confirm previous numerical results, but also elucidate the exact relationships between the various physical properties of the bulk and boundary systems. Our analytic results allow us to study the asymptotic properties that are difficult to probe numerically, such as the near horizon regime of the black hole geometry. We shall also explore a few interesting but hitherto unexplored bulk geometries, such as that corresponding to a boundary critical fermion with nontrivial dynamic critical exponent. Our analytic framework also allows us to study the holographic mapping of some of these boundary theories in dimensions 2+1 or higher.

Ching Hua Lee; Xiao-Liang Qi

2015-03-30

431

Scanning the Parameter Space of Holographic Superconductors  

E-print Network

We study various physical quantities associated with holographic s-wave superconductors as functions of the scaling dimensions of the dual condensates. A bulk scalar field with negative mass squared $m^2$, satisfying the Breitenlohner-Freedman stability bound and the unitarity bound, and allowed to vary in $0.5$ unit intervals, were considered. We observe that all the physical quantities investigated are sensitive to the scaling dimensions of the dual condensates. For all the $m^2$, the characteristic lengths diverge at the critical temperature in agreement with the Ginzburg-Landau theory. The Ginzburg-Landau parameter, obtained from these length scales indicates that the holographic superconductors can be type I or type II depending on the charge and the scaling dimensions of the dual condensates. For a fixed charge, there exists a critical scaling dimension, above which a holographic superconductor is type I, below which it becomes a type II.

Obinna C. Umeh

2009-07-17

432

Holographic entanglement entropy beyond coherent states  

E-print Network

We study entanglement entropy for a class of states in quantum field theory that are entangled superpositions of coherent states with well-separated supports, analogous to Einstein-Podolsky-Rosen or Bell states. We calculate the contributions beyond the area law in a simple model. In the case of strongly coupled conformal field theories, we argue that these states are holographically dual to superpositions of bulk geometries. We note that for these states one can use the Ryu-Takayanagi holographic entanglement entropy formula to calculate some terms in the entanglement entropy, but that there can be additional O(N^2) contributions. We argue that this class of states includes those generated by local quenches and thus that these cannot be described by a classical dual geometry. These considerations may be important for more fine grained treatments of holographic thermalization.

Curtis T. Asplund

2012-05-25

433

Collapse and Revival in Holographic Quenches  

E-print Network

We study holographic models related to global quantum quenches in finite size systems. The holographic set up describes naturally a CFT, which we consider on a circle and a sphere. The enhanced symmetry of the conformal group on the circle motivates us to compare the evolution in both cases. Depending on the initial conditions, the dual geometry exhibits oscillations that we holographically interpret as revivals of the initial field theory state. On the sphere, this only happens when the energy density created by the quench is small compared to the system size. However on the circle considerably larger energy densities are compatible with revivals. Two different timescales emerge in this latter case. A collapse time, when the system appears to have dephased, and the revival time, when after rephasing the initial state is partially recovered. The ratio of these two times depends upon the initial conditions in a similar way to what is observed in some experimental setups exhibiting collapse and revivals.

Emilia da Silva; Esperanza Lopez; Javier Mas; Alexandre Serantes

2014-12-18

434

Holographic stereograms using new geometrical sampling method  

NASA Astrophysics Data System (ADS)

Sampling method for making 3D animation using computer animation data is presented. Computer animation data has 3D information and displayed with 2D images on the screen or CRT. We divide these 3D animation data into several aspect of views (2D images) and synthesize onto holographic film. After chemical processing we can see 3D images the same as what they have when they are made. Also, using the TFT LCD (liquid crystal device), holographic stereograms can be made easily. In this paper, geometrical method is used in order to easily calculate the sampling angles and TFT LCD to display the 2D images. Experimental results show that this method is very tolerable to be shown with 17 degree for several people. In addition, with these series of stereograms and holographic screen, the 3D movie will be possible.

Kim, Eun-Seok; Choi, Yoon-Sun; Kim, Nam

1998-02-01

435

Charged Rényi entropies and holographic superconductors  

NASA Astrophysics Data System (ADS)

Charged Rényi entropies were recently introduced as a measure of entanglement between different charge sectors of a theory. We investigate the phase structure of charged Rényi entropies for CFTs with a light, charged scalar operator. The charged Rényi entropies are calculated holographically via areas of charged hyperbolic black holes. These black holes can become unstable to the formation of scalar hair at sufficiently low temperature; this is the holographic superconducting instability in hyperbolic space. This implies that the Rényi entropies can be non-analytic in the Rényi parameter n. We find the onset of this instability as a function of the charge and dimension of the scalar operator. We also comment on the relation between the phase structure of these entropies and the phase structure of a holographic superconductor in flat space.

Belin, Alexandre; Hung, Ling-Yan; Maloney, Alexander; Matsuura, Shunji

2015-01-01

436

Correlation between tumor size and blood volume in lung tumors: a prospective study on dual-energy gemstone spectral CT imaging.  

PubMed

The purpose of this study was to investigate the relationship between tumor size and blood volume for patients with lung tumors, using dual-energy computed tomography (DECT) and a gemstone spectral imaging (GSI) viewer. During the period from March 2011 to March 2013, 50 patients with 57 medically inoperable lung tumors underwent DECT before stereotactic body radiotherapy (SBRT) of 50-60 Gy in 5-6 fractions. DECT was taken for pretreatment evaluation. The region-of-interest for a given spatial placement of the tumors was set, and averages for CT value, water density and iodine density were compared with tumor size. The average values for iodine density in tumors of ? 2 cm, 2-3 cm, and >3 cm maximum diameter were 24.7, 19.6 and 16.0 (100 µg/cm(3)), respectively. The average value of the iodine density was significantly lower in larger tumors. No significant correlation was detected between tumor size and average CT value or between tumor size and average water density. Both the average water density and the average CT value were affected by the amount of air in the tumor, but the average iodine density was not affected by air in the tumor. The average water density and the average CT value were significantly correlated, but the average iodine density and the average CT value showed no significant correlation. The blood volume of tumors can be indicated by the average iodine density more accurately than it can by the average CT value. The average iodine density as assessed by DECT might be a non-invasive and quantitative assessment of the radio-resistance ascribable to the hypoxic cell population in a tumor. PMID:24829253

Aoki, Masahiko; Takai, Yoshihiro; Narita, Yuichiro; Hirose, Katsumi; Sato, Mariko; Akimoto, Hiroyoshi; Kawaguchi, Hideo; Hatayama, Yoshiomi; Miura, Hiroyuki; Ono, Shuichi

2014-09-01

437

Correlation between tumor size and blood volume in lung tumors: a prospective study on dual-energy gemstone spectral CT imaging  

PubMed Central

The purpose of this study was to investigate the relationship between tumor size and blood volume for patients with lung tumors, using dual-energy computed tomography (DECT) and a gemstone spectral imaging (GSI) viewer. During the period from March 2011 to March 2013, 50 patients with 57 medically inoperable lung tumors underwent DECT before stereotactic body radiotherapy (SBRT) of 50–60 Gy in 5–6 fractions. DECT was taken for pretreatment evaluation. The region-of-interest for a given spatial placement of the tumors was set, and averages for CT value, water density and iodine density were compared with tumor size. The average values for iodine density in tumors of ?2 cm, 2–3 cm, and >3 cm maximum diameter were 24.7, 19.6 and 16.0 (100 µg/cm3), respectively. The average value of the iodine density was significantly lower in larger tumors. No significant correlation was detected between tumor size and average CT value or between tumor size and average water density. Both the average water density and the average CT value were affected by the amount of air in the tumor, but the average iodine density was not affected by air in the tumor. The average water density and the average CT value were significantly correlated, but the average iodine density and the average CT value showed no significant correlation. The blood volume of tumors can be indicated by the average iodine density more accurately than it can by the average CT value. The average iodine density as assessed by DECT might be a non-invasive and quantitative assessment of the radio-resistance ascribable to the hypoxic cell population in a tumor. PMID:24829253

Aoki, Masahiko; Takai, Yoshihiro; Narita, Yuichiro; Hirose, Katsumi; Sato, Mariko; Akimoto, Hiroyoshi; Kawaguchi, Hideo; Hatayama, Yoshiomi; Miura, Hiroyuki; Ono, Shuichi

2014-01-01

438

Phase-imaging holographic microscope  

NASA Astrophysics Data System (ADS)

A real-time holographic microscope for phase imaging is described. The image-formation process is based on the aberration-correcting capability of phase-conjugate illumination. After it has passed through a phase object, the light from a laser beam is recorded as a reflection hologram within a crystal of barium titanate by the self-pumping process. Such a reflection hologram, when illuminated, returns the phase conjugate of the incident distorted optical field. The object is then displaced slightly, and the phase conjugate of the field produced by the undisplaced object now passes through the displaced object. This produces in the object plane an intensity pattern that is an image of gradients in phase retardation. A microscope (objective and ocular) creates a magnified image of the pattern. A digital processor grabs video frames, subtracting from the gradient image the initial optical field acquired before the shift. The subtractive processing results in a final image free of coherent noise and artifacts. We describe the microscope and its operation and show representative images.

Brody, Philip S.; Garvin, Charles G.; Gillman, Arthur W.; Shentu, Lian

1994-05-01

439

Holographic entropy and Calabi's diastasis  

NASA Astrophysics Data System (ADS)

The entanglement entropy for interfaces and junctions of two-dimensional CFTs is evaluated on holographically dual half-BPS solutions to six-dimensional Type 4b supergravity with m anti-symmetric tensor supermultiplets. It is shown that the moduli space for an N-junction solution projects to N points in the Kähler manifold SO(2 , m) / (SO(2) × SO( m)). For N =2 the interface entropy is expressed in terms of the central charge and Calabi's diastasis function on SO(2 , m) / (SO(2) × SO( m)), thereby lending support from holography to a proposal of Bachas, Brunner, Douglas, and Rastelli. For N =3, the entanglement entropy for a 3-junction decomposes into a sum of diastasis functions between pairs, weighed by combinations of the three central charges, provided the flux charges are all parallel to one another or, more generally, provided the space of flux charges is orthogonal to the space of unattracted scalars. Under similar assumptions for N ?4, the entanglement entropy for the N -junction solves a variational problem whose data consist of the N central charges, and the diastasis function evaluated between pairs of N asymptotic AdS 3 × S 3 regions.

D'Hoker, Eric; Gutperle, Michael

2014-10-01

440

Light-Front Holographic QCD  

SciTech Connect

The relation between the hadronic short-distance constituent quark and gluon particle limit and the long-range confining domain is yet one of the most challenging aspects of particle physics due to the strong coupling nature of Quantum Chromodynamics, the fundamental theory of the strong interactions. The central question is how one can compute hadronic properties from first principles; i.e., directly from the QCD Lagrangian. The most successful theoretical approach thus far has been to quantize QCD on discrete lattices in Euclidean space-time. Lattice numerical results follow from computation of frame-dependent moments of distributions in Euclidean space and dynamical observables in Minkowski spacetime, such as the time-like hadronic form factors, are not amenable to Euclidean lattice computations. The Dyson-Schwinger methods have led to many important insights, such as the infrared fixed point behavior of the strong coupling constant, but in practice, the analyses are limited to ladder approximation in Landau gauge. Baryon spectroscopy and the excitation dynamics of nucleon resonances encoded in the nucleon transition form factors can provide fundamental insight into the strong-coupling dynamics of QCD. New theoretical tools are thus of primary interest for the interpretation of the results expected at the new mass scale and kinematic regions accessible to the JLab 12 GeV Upgrade Project. The AdS/CFT correspondence between gravity or string theory on a higher-dimensional anti-de Sitter (AdS) space and conformal field theories in physical space-time has led to a semiclassical approximation for strongly-coupled QCD, which provides physical insights into its nonperturbative dynamics. The correspondence is holographic in the sense that it determines a duality between theories in different number of space-time dimensions. This geometric approach leads in fact to a simple analytical and phenomenologically compelling nonperturbative approximation to the full light-front QCD Hamiltonian 'Light-Front Holography'. Light-Front Holography is in fact one of the most remarkable features of the AdS/CFT correspondence. The Hamiltonian equation of motion in the light-front (LF) is frame independent and has a structure similar to eigenmode equations in AdS space. This makes a direct connection of QCD with AdS/CFT methods possible. Remarkably, the AdS equations correspond to the kinetic energy terms of the partons inside a hadron, whereas the interaction terms build confinement and correspond to the truncation of AdS space in an effective dual gravity approximation. One can also study the gauge/gravity duality starting from the bound-state structure of hadrons in QCD quantized in the light-front. The LF Lorentz-invariant Hamiltonian equation for the relativistic bound-state system is P{sub {mu}}P{sup {mu}}|{psi}(P)> = (P{sup +}P{sup -} - P{sub {perpendicular}}{sup 2})|{psi}(P)> = M{sup 2}|{psi}(P)>, P{sup {+-}} = P{sup 0} {+-} P{sup 3}, where the LF time evolution operator P{sup -} is determined canonically from the QCD Lagrangian. To a first semiclassical approximation, where quantum loops and quark masses are not included, this leads to a LF Hamiltonian equation which describes the bound-state dynamics of light hadrons in terms of an invariant impact variable {zeta} which measures the separation of the partons within the hadron at equal light-front time {tau} = x{sup 0} + x{sup 3}. This allows us to identify the holographic variable z in AdS space with an impact variable {zeta}. The resulting Lorentz-invariant Schroedinger equation for general spin incorporates color confinement and is systematically improvable. Light-front holographic methods were originally introduced by matching the electromagnetic current matrix elements in AdS space with the corresponding expression using LF theory in physical space time. It was also shown that one obtains identical holographic mapping using the matrix elements of the energy-momentum tensor by perturbing the AdS metric around its static solution. A gravity dual to QCD is not known, but th

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.; /Costa Rica U.

2012-02-16

441

Off-axis full-field swept-source optical coherence tomography using holographic refocusing  

NASA Astrophysics Data System (ADS)

We demonstrate a full-field swept-source OCT using an off-axis geometry of the reference illumination. By using holographic refocusing techniques, a uniform lateral resolution is achieved over the measurement depth of approximately 80 Rayleigh lengths. Compared to a standard on-axis setup, artifacts and autocorrelation signals are suppressed and the measurement depth is doubled by resolving the complex conjugate ambiguity. Holographic refocusing was done efficiently by Fourier-domain resampling as demonstrated before in inverse scattering and holoscopy. It allowed to reconstruct a complete volume with about 10?m resolution over the complete measurement depth of more than 10mm. Off-axis full-field swept-source OCT enables high measurement depths, spanning many Rayleigh lengths with reduced artifacts.

Hillmann, Dierck; Franke, Gesa; Hinkel, Laura; Bonin, Tim; Koch, Peter; Hüttmann, Gereon

2013-03-01

442

Planck constraints on holographic dark energy  

SciTech Connect

We perform a detailed investigation on the cosmological constraints on the holographic dark energy (HDE) model by using the Plank data. We find that HDE can provide a good fit to the Plank high-l (l ?> 40) temperature power spectrum, while the discrepancy at l ? 20-40 found in the ?CDM model remains unsolved in the HDE model. The Plank data alone can lead to strong and reliable constraint on the HDE parameter c. At the 68% confidence level (CL), we obtain c = 0.508 ± 0.207 with Plank+WP+lensing, favoring the present phantom behavior of HDE at the more than 2? CL. By combining Plank+WP with the external astrophysical data sets, i.e. the BAO measurements from 6dFGS+SDSS DR7(R)+BOSS DR9, the direct Hubble constant measurement result (H{sub 0} = 73.8 ± 2.4 kms{sup ?1}Mpc{sup ?1}) from the HST, the SNLS3 supernovae data set, and Union2.1 supernovae data set, we get the 68% CL constraint results c = 0.484 ± 0.070, 0.474 ± 0.049, 0.594 ± 0.051, and 0.642 ± 0.066, respectively. The constraints can be improved by 2%-15% if we further add the Plank lensing data into the analysis. Compared with the WMAP-9 results, the Plank results reduce the error by 30%-60%, and prefer a phantom-like HDE at higher significant level. We also investigate the tension between different data sets. We find no evident tension when we combine Plank data with BAO and HST. Especially, we find that the strong correlation between ?{sub m}h{sup 3} and dark energy parameters is helpful in relieving the tension between the Plank and HST measurements. The residual value of ?{sup 2}{sub Plank+WP+HST}??{sup 2}{sub Plank+WP} is 7.8 in the ?CDM model, and is reduced to 1.0 or 0.3 if we switch the dark energy to w model or the holographic model. When we introduce supernovae data sets into the analysis, some tension appears. We find that the SNLS3 data set is in tension with all other data sets; for example, for the Plank+WP, WMAP-9 and BAO+HST, the corresponding ??{sup 2} is equal to 6.4, 3.5 and 4.1, respectively. As a comparison, the Union2.1 data set is consistent with these three data sets, but the combination Union2.1+BAO+HST is in tension with Plank+WP+lensing, corresponding to a large ??{sup 2} that is equal to 8.6 (1.4% probability). Thus, combining internal inconsistent data sets (SNIa+BAO+HST with Plank+WP+lensing) can lead to ambiguous results, and it is necessary to perform the HDE data analysis for each independent data sets. Our tightest self-consistent constraint is c = 0.495 ± 0.039 obtained from Plank+WP+BAO+HST+lensing.

Li, Miao; Zhang, Zhenhui [Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Li, Xiao-Dong [Korea Institute for Advanced Study, Hoegiro 87, Dongdaemun-Gu, Seoul 130-722 (Korea, Republic of); Ma, Yin-Zhe [Department of Physics and Astronomy, University of British Columbia, Vancouver, V6T 1Z1, BC Canada (Canada); Zhang, Xin, E-mail: mli@itp.ac.cn, E-mail: xiaodongli@kias.re.kr, E-mail: mayinzhe@phas.ubc.ca, E-mail: zhangxin@mail.neu.edu.cn, E-mail: zhangzhh@itp.ac.cn [College of Sciences, Northeastern University, Shenyang 110004 (China)

2013-09-01

443

Area Operators in Holographic Quantum Gravity  

E-print Network

We argue that the holographic formula relating entanglement entropy and the area of a minimal surface is the key to define the area of surfaces in the (emergent) spacetime from the dual theory on the boundary. So we promote the entropy/area relation to operators to define the "area" observable in a holographic formulation of quantum gravity, then we find a suitable geometric representation for the states, and show that the Ryu-Takayanagi proposal is recovered in the approximation of semi-classical gravity. Finally, we discuss this picture in the example of a AdS-Black hole.

Marcelo Botta Cantcheff

2014-04-11

444

On the Holographic Nature Of Rindler Energy  

E-print Network

We show that the dimensionless Rindler energy of a black hole, $E_R$, is exactly the surface Hamiltonian obtained from the Einstein--Hilbert action evaluated on the horizon. Therefore, $E_R$ is given by a surface integral over the horizon and manifestly holographic. In the context of the AdS/CFT duality, Rindler energy corresponds, on the boundary, to a dimensionless energy given by the product of the AdS radius and the extensive part of the CFT energy. We find that, beyond General Relativity, $E_R$ is still holographic but not necessarily given by the surface Hamiltonian of the theory.

Edi Halyo

2014-06-22

445

Holographic superconductors from the massive gravity  

E-print Network

A holographic superconductor is constructed in the background of a massive gravity theory. In the normal state without condensation, the conductivity exhibits a Drude peak that approaches a delta function in the massless gravity limit as studied by David Vegh. In the superconducting state, besides the infinite DC conductivity, the AC conductivity has Drude behavior at low frequency followed by a power law-fall. These results are in agreement with that found earlier by Horowitz and Santos, who studied a holographic superconductor with an implicit periodic potential beyond the probe limit. The results also agree with measurements on some cuprates.

Hua Bi Zeng; Jian-Pin Wu

2014-09-24

446

Impurity effect in a holographic superconductor  

E-print Network

We consider a holographic superconductor with homogeneous impurities added. We start with the holographic Abelian-Higgs model for s-wave superconductivity, and turn on a coupling between the gauge field and a new massive gauge field that is introduced for impurities, whose effect is examined in the probe limit. We find that the condensation of the massive gauge field is induced in the superconducting phase. When the coupling is sufficiently large, the mass gap in the optical conductivity disappears. A resonance peak is found in the conductivity for the massive vector field.

Takaaki Ishii; Sang-Jin Sin

2013-01-30

447

Vortex lattice for a holographic superconductor  

E-print Network

We investigate the vortex lattice solution in a (2+1)-dimensional holographic model of superconductors constructed from a charged scalar condensate. The solution is obtained perturbatively near the second-order phase transition and is a holographic realization of the Abrikosov lattice. Below a critical value of magnetic field, the solution has a lower free energy than the normal state. Both the free energy density and the superconducting current are expressed by nonlocal functions, but they reduce to the expressions in the Ginzburg-Landau (GL) theory at long wavelength. As a result, a triangular lattice becomes the most favorable solution thermodynamically as in the GL theory of type II superconductors.

Kengo Maeda; Makoto Natsuume; Takashi Okamura

2009-12-17

448

Real-time wideband holographic surveillance system  

DOEpatents

A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm.

Sheen, David M. (1917 Hood, Richland, WA 99352); Collins, H. Dale (1751 Duluth, Richland, WA 99352); Hall, Thomas E. (8301 W. Entiat Pl., Kennewick, WA 99336); McMakin, Douglas L. (2173 Shasta Ave., Richland, WA 99352); Gribble, R. Parks (1215 Cottonwood Dr., Richland, WA 99352); Severtsen, Ronald H. (1803 Birch Ave., Richland, WA 99352); Prince, James M. (3029 W. 2nd Ave., Apt. F95, Kennewick, WA 99336); Reid, Larry D. (Rt. 1, Box 1291B, Benton City, WA 99320)

1996-01-01

449

Shape of mesons in holographic QCD  

SciTech Connect

Based on the expectation that the constituent quark model may capture the right physics in the large N limit, we point out that the orbital angular momentum of the quark-antiquark pair inside light mesons of low spins in the constituent quark model may provide a clue for the holographic dual string model of large N QCD. Our discussion, relying on a few suggestive assumptions, leads to a necessity of world-sheet fermions in the bulk of dual strings that can incorporate intrinsic spins of fundamental QCD degrees of freedom. We also comment on the interesting issue of the size of mesons in holographic QCD.

Torabian, Mahdi; Yee, Ho-Ung [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34014, Trieste (Italy)

2009-10-15

450

The Shape of Mesons in Holographic QCD  

E-print Network

Based on the expectation that constituent quark model may capture right physics in the large N limit, we point out that orbital angular momentum of the quark-antiquark pair inside light mesons of low spins in the constituent quark model may provide a clue for the holographic dual string model of large N QCD. Our discussion, relying on a few suggestive assumptions, leads to a necessity of world-sheet fermions in the bulk of dual strings that can incorporate intrinsic spins of fundamental QCD degrees of freedom. We also comment on an interesting issue of the size of mesons in the context of holographic QCD.

Mahdi Torabian; Ho-Ung Yee

2009-10-07

451

Holographic Dark Energy Model: State Finder Parameters  

E-print Network

In this work, we have studied interacting holographic dark energy model in the background of FRW model of the universe. The interaction is chosen either in linear combination or in product form of the matter densities for dark matter and dark energy. The IR cut off for holographic dark energy is chosen as Ricci's length scale or radius of the future event horizon. The analysis is done using the state finder parameter and coincidence problem has been graphically presented. Finally, universal thermodynamics has been studied using state finder parameters.

Nairwita Mazumder; Ritabrata Biswas; Subenoy Chakraborty

2011-10-30

452

Interacting holographic dark energy with logarithmic correction  

SciTech Connect

The holographic dark energy (HDE) is considered to be the most promising candidate of dark energy. Its definition is motivated from the entropy-area relation which depends on the theory of gravity under consideration. Recently a new definition of HDE is proposed with the help of quantum corrections to the entropy-area relation in the setup of loop quantum cosmology. Employing this new definition, we investigate the model of interacting dark energy and derive its effective equation of state. Finally we establish a correspondence between generalized Chaplygin gas and entropy-corrected holographic dark energy.

Jamil, Mubasher; Farooq, M. Umar, E-mail: mjamil@camp.nust.edu.pk, E-mail: mufarooq@yahoo.com [Center for Advanced Mathematics and Physics, National University of Sciences and Technology, Rawalpindi, 46000 (Pakistan)

2010-03-01

453

Holographic Projection Technology: The World is Changing  

E-print Network

This research papers examines the new technology of Holographic Projections. It highlights the importance and need of this technology and how it represents the new wave in the future of technology and communications, the different application of the technology, the fields of life it will dramatically affect including business, education, telecommunication and healthcare. The paper also discusses the future of holographic technology and how it will prevail in the coming years highlighting how it will also affect and reshape many other fields of life, technologies and businesses.

Elmorshidy, Ahmed

2010-01-01

454

Interacting holographic dark energy with logarithmic correction  

E-print Network

The holographic dark energy (HDE) is considered to be the most promising candidate of dark energy. Its definition is originally motivated from the entropy-area relation which depends on the theory of gravity under consideration. Recently a new definition of HDE is proposed with the help of quantum corrections to the entropy-area relation in the setup of loop quantum cosmology. Using this new definition, we investigate the model of interacting dark energy and derive its effective equation of state. Finally we establish a correspondence between generalized Chaplygin gas and entropy-corrected holographic dark energy.

Mubasher Jamil; M. Umar Farooq

2010-03-01

455

Holographic RG flows with nematic IR phases  

E-print Network

We construct zero-temperature geometries that interpolate between a Lifshitz fixed point in the UV and an IR phase that breaks spatial rotations but preserves translations. We work with a simple holographic model describing two massive gauge fields coupled to gravity and a neutral scalar. Our construction can be used to describe RG flows in non-relativistic, strongly coupled quantum systems with nematic order in the IR. In particular, when the dynamical critical exponent of the UV fixed point is z=2 and the IR scaling exponents are chosen appropriately, our model realizes holographically the scaling properties of the bosonic modes of the quadratic band crossing model.

Sera Cremonini; Xi Dong; Junchen Rong; Kai Sun

2015-01-22

456

Real-time holographic surveillance system  

DOEpatents

A holographic surveillance system is disclosed including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm. 21 figs.

Collins, H.D.; McMakin, D.L.; Hall, T.E.; Gribble, R.P.

1995-10-03

457

Real-time holographic surveillance system  

DOEpatents

A holographic surveillance system including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm.

Collins, H. Dale (Richland, WA); McMakin, Douglas L. (Richland, WA); Hall, Thomas E. (Kennewick, WA); Gribble, R. Parks (Richland, WA)

1995-01-01

458

Real-time wideband holographic surveillance system  

DOEpatents

A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm. 28 figs.

Sheen, D.M.; Collins, H.D.; Hall, T.E.; McMakin, D.L.; Gribble, R.P.; Severtsen, R.H.; Prince, J.M.; Reid, L.D.

1996-09-17