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1

Rotation-invariant scene matching with multi-sample parallel estimation in volume holographic correlator  

NASA Astrophysics Data System (ADS)

The volume holographic correlator can be used in the fast scene matching. However, the traditional volume holographic recognition method is unable to implement rotation-invariant scene matching. In the multi-sample parallel estimation method, the intensity of the multiple correlation spots can also reflect the information of the rotation angle between the target image and the template image. Thus it can be used to derive the rotation angle in the post processing and the rotation-invariant scene matching can be realized. The function between the rotation angle and the intensity value of the correlation spots is presented. The experimental results show the validity of the proposed method. The rotation angle of the target image can be precisely derived and the maximum rotation angle is as big as five degree. This method is able to save much capacity of the volume holographic correlator, enlarge the scene matching scope and improve the recognition accuracy.

Wang, Shunli; Cao, Liangcai; He, Qingsheng; Jin, Guofan

2010-11-01

2

Large range rotation distortion measurement for remote sensing images based on volume holographic optical correlator  

NASA Astrophysics Data System (ADS)

Volume holographic optical correlator can compute the correlation results between images at a super-high speed. In the application of remote imaging processing such as scene matching, 6,000 template images have been angularly multiplexed in the photorefractive crystal and the 6,000 parallel processing channels are achieved. In order to detect the correlation pattern of images precisely and distinguishingly, an on-off pixel inverted technology of images is proposed. It can fully use the CCD's linear range for detection and expand the normalized correlation value differences as the target image rotates. Due to the natural characteristics of the remote sensing images, the statistical formulas between the rotation distortions and the correlation results can be estimated. The rotation distortion components can be estimated by curve fitting method with the data of correlation results. The intensities of the correlation spots are related to the distortion between the two images. The rotation distortion could be derived from the intensities in the post processing procedure. With 18 rotations of the input image and sending them into the volume holographic system, the detection of the rotation variation in the range of 180° can be fulfilled. So the large range rotation distortion detection is firstly realized. It offers a fast, large range rotation measurement method for image distortions.

Zheng, Tianxiang; Cao, Liangcai; Zhao, Tian; He, Qingsheng; Jin, Guofan

2012-10-01

3

Influence of readout optical field variations on inner product calculation in volume holographic correlator  

NASA Astrophysics Data System (ADS)

The volume holographic correlator (VHC) can be employed as a multichannel inner product calculator and has the potential in parallel and massive computing applications. The inner product calculation accuracy of the VHC varies with the optical illumination field in the plane of the spatial light modulator during readout. A theoretical model of the VHC is presented to study the influence of the optical field variations. The simulation results are shown to examine the cases of illumination angle deviation and wavelength deviation. The influences of hologram thickness on the calculation are also discussed. Experiments are carried out to investigate illumination angle deviation of the VHC. The presented method is helpful to improve the inner product calculation accuracy in the VHC for parallel optical image processing.

Zhao, Tian; Cao, Liangcai; Qin, Shuang; He, Qingsheng; Jin, Guofan

2013-07-01

4

Polarized, phase-encoded and 2D angular multiplexed volume holographic correlator  

NASA Astrophysics Data System (ADS)

The volume holographic correlator (VHC) is a highly parallel processor. For an angularly multiplexed VHC, the processing speed is limited by the ratio of the maximum angle range and the minimum angle interval of the reference beam. Limited by the angle scanning range of the reference beam, the pure angular multiplexing in the reference beam of the VHC can only establish thousands of parallel correlation channels, which is far from the high parallelism demand for real-time applications. In this paper, the maximum multiplexing number of the VHC system is increased. The polarized and phase-encoded multiplexing methods are introduced into the object beam, with the angular multiplexing method in the reference beam. The mutual orthogonality of the polarization multiplexing, phase-encoded multiplexing and angular multiplexing methods are verified with experiment. This shows that the number of parallel channels can be increased with the object beam both polarized and phase-encoded multiplexed and with the reference beam still angularly multiplexed in the VHC. The optical setup is established and the feasibility of the proposed hybrid multiplexing method is experimentally verified. The two multiplexing methods extended to the object beam make it possible to establish more parallel correlation channels in the VHC. Although millions of parallel correlation channels can be realized with the proposed multiplexing method in theory, the paper presents some principal experimental results.

Zheng, Tianxiang; Cao, Liangcai; Li, Chengmingyue; He, Qingsheng; Jin, Guofan

2014-05-01

5

Imaging characteristics of a volume holographic lens  

NASA Astrophysics Data System (ADS)

A volume holographic grating lens can reconstruct the three-dimensional information by conducting multiple optical slicing of an object based on Bragg selectivity of the volume holographic grating. In this paper, we employ the point-spread function of volume holographic imaging system to theoretically analyze its imaging resolution. In the experiments, the volume holographic gratings are made with a spherical reference (SR) and a planar reference (PR), respectively, and used as volume holographic imaging lens in our imaging system. The longitudinal and lateral defocusing characteristics of volume holographic lens with SR and with PR are investigated experimentally by displacing the interested objects from original reference location, respectively. The effects of the parameters of the volume holographic lens on the longitudinal and lateral resolution are also discussed. The experimental results show that increasing the size of the volume holographic lens can improve the depth resolution, and in particular, it has greater influence on SR VHI. The lateral selectivity of SR VHI is more sensitive than that of PR VHI, and the Bragg degenerate diffraction of PR VHI on the y axis is obviously observed.

Yang, Jing; Jiang, Zhu-qing; Xu, Zhi-qiang; Liu, Shao-jie; Sun, Ya-jun; Tao, Shi-quan

2009-07-01

6

Multilayer Volume Holographic Optical Memory  

NASA Technical Reports Server (NTRS)

We demonstrate a scheme for volume holographic storage based on the features of shift selectivity of a speckle reference wave hologram. The proposed recording method allows more efficient use of the recording medium and increases the storage density in comparison with spherical or plane-wave reference beams. Experimental results of multiple hologram storage and replay in a photorefractive crystal of iron-doped lithium niobate are presented. The mechanism of lateral and longitudinal shift selectivity are described theoretically and shown to agree with experimental measurements.

Markov, Vladimir; Millerd, James; Trolinger, James; Norrie, Mark; Downie, John; Timucin, Dogan; Lau, Sonie (Technical Monitor)

1998-01-01

7

Holographic Grating Study. Volume 1.  

National Technical Information Service (NTIS)

The two primary goals of the study were to demonstrate the feasibility of fabricating low and high-efficiency ion-machined holographic gratings and, by means of optical analysis, to establish their suitability for use in practical high-energy laser system...

J. O. Garvey, R. J. Withrington, O. G. Ramer, A. A. Livanos, A. C. Livanos

1979-01-01

8

Sensitivity of volume holographic optical computing  

NASA Astrophysics Data System (ADS)

Volume holographic correlator (VHC) calculates the inner product between two data pages through parallel optical correlation. It has great potential in the field of information processing and real-time identification because of its high storage density, integration of storing and computing, and multi-channel parallel processing ability. Current studies on the improvements of VHC mainly focus on the processing speed and channel uniformity. However, the accuracy of the VHC is mainly related to the minimum output intensity varying with the spatial light modulator (SLM) pixel intensity, which is the sensitivity of the VHC. In this work, the Minimum Pixel Block Size (MPBS) is proposed to characterize the sensitivity of the VHC. The Effective Number of Pixels (ENP) is employed to evaluate the optical computing ability, which is more accurate compared with traditional calculating method based on the pixel number of the SLM. The theoretical and experimental results are instructive in the system design. Desired system performance can be achieved by optimizing the system parameters.

Yi, Yao; Cao, Liang-cai; Zheng, Tian-xiang; Guo, Wei; He, Qing-sheng; Jin, Guo-fan

2013-08-01

9

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

10

Correlation functions in the holographic replica method  

NASA Astrophysics Data System (ADS)

Disorder has long been a difficult subject in condensed matter systems and the The replica method is a well-known tool in this field. Implementing the replica method the AdS/CFT correspondence has been proposed and discussed in literatures. We point out, for any CFT that has a holographic dual and to the leading order of the large- N expansion, the corrections due to the presence of random disorder to any connected correlation functions vanish identically, provided that the disorder strength is normalized as discussed in literatures and that the symmetry among replicas is unbroken. Same must hold true to any observables that are determined by the connected correlation functions through a linear relation. This behavior resembles strongly that of a free theory where disorder is coupled to the fundamental field. We demonstrate this by both the means of holographic principle and field theory analysis in a toy model. We also propose ways of evaluating the non-zero sub-leading effects perturbatively in terms of the disorder strength and discuss a novel possibility of defining a new holographic dual if we adopt a different normalization for the disorder strength.

Shang, Yanwen

2012-12-01

11

Hybrid integrated optics in volume holographic photopolymer  

NASA Astrophysics Data System (ADS)

Traditional planar lightwave circuits fabricated from lithographically-patterned waveguides in glasses, semi-conductors or polymers cannot accommodate the wide range of materials required by typical optical devices. In addition, such waveguides are nearly always defined in the material surface and thus can support only a limited density of interconnects and suffer poor performance at waveguide crossings. Furthermore, the inflexibility of lithographic approaches - including both waveguides and "silicon-bench" methods - requires optical sub-components with unreasonable and expensive tolerances. We propose an alternative integrated optics platform based on 3D direct-write lithography into an optically addressable encapsulant. Arbitrary micro-optics are first embedded in a liquid monomer which is then cured into a semi-solid pre-polymer. It is essential that this step take place with minimal shrinkage to avoid stresses. A scanning confocal microscope then nondestructively identifies the component locations and their tolerances. The controller customizes the circuit design to accommodate these tolerances and then scans a 0.3 to 0.6 NA focus within the volume of the holographic polymer to create waveguides, lenses or other passive interconnects with one micron resolution. A final incoherent exposure cures and solidifies the polymer, finishing the process. The resulting hybrid optoelectronic circuits contain 3D routed waveguides interconnecting active and passive micro-optic devices in environmentally robust, hermetically sealed packages. A feature of particular interest is the ability to write waveguides directly off of the tips of embedded fibers, passively interfacing the circuits to fiber. We show that polymers developed for holographic data storage have the properties required for this application.

McLeod, Robert R.; Sullivan, Amy C.; Grabowski, Matthew W.; Scott, Timothy F.

2004-10-01

12

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

13

Volume polarization holographic recording in thick photopolymer for optical memory.  

PubMed

Based on a vector wave theory of volume holograms, dependence of holographic reconstruction on the polarization states of the writing and reading beams is discussed. It is found that under paraxial approximation the circular polarization holograms provide a better distinction of the reading beams. Characteristics of recording polarization holograms in thick phenanthrenequinone-doped poly(methyl methacrylate) (PQ/PMMA) photopolymer are experimentally investigated. It is found that the circular polarization holographic recording possesses better dynamic range and material sensitivity, and a uniform spatial frequency response over a wide range. The performance is comparable to that of the intensity holographic recording in PQ/PMMA. Based on theoretical analyses and the material properties, a polarization multiplexing holographic memory using circularly polarization recording configuration for increasing storage capacity has been designed and experimentally demonstrated. PMID:24977588

Lin, Shiuan Huei; Cho, Sheng-Lung; Chou, Shin-Fu; Lin, June Hua; Lin, Chih Min; Chi, Sien; Hsu, Ken Yuh

2014-06-16

14

Volume holographic storage demonstrator based on phase-coded multiplexing  

Microsoft Academic Search

We present the design and realization of a compact volume holographic memory based on phase-coded multiplexing. Due to the use of nonmechanical reference beam changes in this multiplexing technique, rapid access of the stored data pages is achieved. Our system can reach a maximum storage capacity up to 480 data pages with a resolution of 640×480 pixels in a single

Cornelia Denz; K.-O. Muller; T. Heimann; T. Tschudi

1998-01-01

15

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

16

Translation-invariant object recognition system using an optical correlator and a super-parallel holographic random access memory  

NASA Astrophysics Data System (ADS)

We demonstrate a translation-invariant VanderLugt correlator (VLC) for a set of images stored via holographic angle multiplexing of volume gratings in a polymeric substrate. The images read out from the volume gratings are optically correlated in a translation-invariant manner with a dc-suppressed holographic filter. The quality and efficiency of this correlator are observed to be nearly as good as that of another VLC with images directly from a spatial light modulator used as inputs. This experiment is the first step toward realizing a novel optical image recognition system capable of identifying a query image through an exhaustive search in a large database of filter images stored in an ultrahigh capacity superparallel holographic random access memory (SPHRAM). In this system, the identification of the query image is to be performed with a translation invariant, real-time VLC or a joint transform correlator (JTC).

Heifetz, Alexander; Shen, John T.; Lee, Jong-Kwon; Tripathi, Renu; Shahriar, M. S.

2006-02-01

17

Volume holographic imaging for surface metrology at long working distances  

NASA Astrophysics Data System (ADS)

We present an imaging scheme that takes advantage of the superior lateral resolution of volume holographic imaging (VHI)[1] and a-priori surface information about the object to build a profilometer that can resolve 50 µm longitudinal features at a working distance of Â¡Ö 50 cm with a single VHI camera. We discuss the scheme and present experimental results of surface profiles of MEMS devices.

Sinha, Arnab; Barbastathis, George

2003-12-01

18

Volume holographic imaging for surface metrology with long working distances  

NASA Astrophysics Data System (ADS)

Volume holographic imaging (VHI) utilizes the Bragg selectivity of volume holograms to achieve 3D optical slicing. The depth resolution of VHI degrades quadratically with increasing object distance like most 3D imaging systems. We have devised an imaging scheme that takes advantage of the superior lateral resolution of VHI and a-priori surface information about the object to build a profilometer that can resolve 50 ?m features at a working distance of ~ 50 cm. We discuss the scheme and present experimental results of surface profiles of MEMS devices.

Sinha, Arnab; Sun, Wenyang; Shih, Tina; Barbastathis, George

2004-02-01

19

Numerical simulations of volume holographic imaging system resolution characteristics  

NASA Astrophysics Data System (ADS)

Because of the Bragg selectivity of volume holographic gratings, it helps VHI system to optically segment the object space. In this paper, properties of point-source diffraction imaging in terms of the point-spread function (PSF) are investigated, and characteristics of depth and lateral resolutions in a VHI system is numerically simulated. The results show that the observed diffracted field obviously changes with the displacement in the z direction, and is nearly unchanged with displacement in the x and y directions. The dependence of the diffracted imaging field on the z-displacement provides a way to possess 3-D image by VHI.

Sun, Yajun; Jiang, Zhuqing; Liu, Shaojie; Tao, Shiquan

2009-05-01

20

Prism-coupled lenslet array for a super-parallel holographic correlator  

Microsoft Academic Search

We propose a design for a prism-coupled lenslet array (PCLLA) which is a key component in certain parallel-access holographic data processing systems. These systems, the super-parallel holographic optical correlator and the super-parallel holographic random access memory, have the potential to be useful in target tracking, identification, and optical information processing applications. We derive the phase transformation required by these architectures

J. T. Shen; A. Heifetz; G. S. Pati; M. S. Shahriar

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

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

23

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

24

SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Optical neural networks based on holographic correlators  

NASA Astrophysics Data System (ADS)

The three most important models of neural networks — a bidirectional associative memory, Hopfield networks, and adaptive resonance networks — are used as examples to show that a holographic correlator has its place in the neural computing paradigm.

Sokolov, V. K.; Shubnikov, E. I.

1995-10-01

25

Sparse Modulation Coding for Increased Capacity in Volume Holographic Storage  

NASA Astrophysics Data System (ADS)

In page-oriented memories, data pages commonly consist of comparable numbers of on and off pixels. Data-page sparsity is defined by reduction of the number of on pixels per page, leading to an increased diffracted power into each pixel. When page retrieval is dominated by a fixed noise floor, the number of pages in the memory is limited by the pixel diffraction efficiency. Sparsity increases the number of storable pages while reducing the amount of user information per page. A detailed analysis of sparsity in volume holographic memories shows that the total memory capacity can be increased by 15% by use of data pages that contain on average 25% on pixels. Sparsity also helps to reduce the effects of interpixel cross talk by strongly reducing the probability that worst-case pixel patterns (e.g., blocks of on pixels with a center off pixel) will occur in the data page. Enumeration block coding techniques provide construction of sparse-data pages with minimal overhead. In addition, enumeration coding offers maximum-likelihood detection with low encoding decoding latency. We discuss the theoretical advantages of data-page sparsity. We also present experimental results that demonstrate the proposed capacity gain. The experiment verifies that it is practical to construct and use sparse-data pages that result in an overall user capacity gain of 16% subject to a page retrieval bit-error rate of 10 4 .

King, Brian M.; Neifeld, Mark A.

2000-12-01

26

Optimization of light diffraction efficiency and its enhancement from a doped-PMMA volume holographic material  

NASA Astrophysics Data System (ADS)

In this paper, we study the diffraction efficiency from the volume gratings in holographic materials, PQ/PMMA, and their efficiency-enhancement in an optically dark environment (dark enhancement). We show that the diffraction efficiency is increased in real-time by light-exposure and then by a slow diffusion process in the dark after light-exposure. We observe strong correlations between the efficiency, the light-exposure energy and the dark-enhancement. Furthermore, we establish an optimum condition for light-exposure and dark-enhancement. Accordingly, we simultaneously achieve the best diffraction-efficiency of 82% for a 2 mm thick PQ/PMMA and an efficiency-enhancement of 3.1 times after exposure, approaching the theoretical limit of 4 times.

Hsieh, Mei-Li; Chenc, Wei-Cheng; Chen, Hong-Yu; Lin, Shawn-Yu

2013-11-01

27

Spatial-spectral volume holographic systems: resolution dependence on effective thickness.  

PubMed

The resolution dependence of spatial-spectral volume holographic imaging systems on angular and spectral bandwidth of nonuniform gratings is investigated. Modeling techniques include a combination of the approximate coupled-wave analysis and the transfer-matrix method for holograms recorded in absorptive media. The effective thickness of the holograms is used as an estimator of the resolution of the imaging systems. The methodology, which assists in the design and optimization of volume holographic simulation results based on our approach, are confirmed with experiments and show proof of consistency and usefulness of the proposed models. PMID:21364728

Castro, Jose M; Brownlee, John; Luo, Yuan; de Leon, Erich; Barton, Jennifer K; Barbastathis, George; Kostuk, Raymond K

2011-03-01

28

Real-time 3D particle manipulation visualized using volume holographic gratings.  

PubMed

Holographic optical tweezers (HOTs) extend optical trapping into three dimensions. Volume imaging then becomes a concern as trapped objects are easily moved out of focus of the imaging objective lens. Here we demonstrate a three-dimensional real-time interactive optical trapping, manipulating, and imaging system based on HOTs incorporated with volume holographic microscope. Intensity information about the trapped objects at multiple depths can be captured in a single measurement. This method is compatible with most imaging modes such as bright-field and fluorescence. PMID:24978278

Chen, Zhi; Chen, Wensheng; Lu, Hsin-yu; Chevallier, Yves; Chen, Nanguang; Barbastathis, George; Luo, Yuan

2014-05-15

29

A 6-beam combiner using superimposed volume index holographic gratings  

E-print Network

splitter, MR: mirror, NDF: neutral density filter?????.??.44 Figure 21. The fringe patterns by interference of each pair of beams. The number below the images notes the numbers of two input beams??.46 Figure 22. Schematic diagrams of ramp... reaches the optimum limit for holographic exposure, the number of interference fringes visible in the diffracted reach a maximum???...?????????????29 Table 2. Experimentally observed transmission and diffraction patterns for 4 superimposed gratings...

Yum, HoNam

2005-11-01

30

Associative memory in a volume holographic medium: a new approach based on operator theory  

NASA Astrophysics Data System (ADS)

In this article, we present a new method for holographic implementation of associative memories. In the current approach, the memory capacity is implemented in the form of spatial perturbation of refractive index within the volume of a three dimensional holographic material. We use operator theory to solve the inverse problem and compute a closed-form solution for the spatial distribution of the perturbation considering any arbitrary set of input-output prototype vectors. Simplicity of the hardware is the major advantage of the current method.

Pashaie, Ramin

2014-07-01

31

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

32

Simulations and experiments of aperiodic and multiplexed gratings in volume holographic imaging systems  

PubMed Central

A new methodology describing the effects of aperiodic and multiplexed gratings in volume holographic imaging systems (VHIS) is presented. The aperiodic gratings are treated as an ensemble of localized planar gratings using coupled wave methods in conjunction with sequential and non-sequential ray-tracing techniques to accurately predict volumetric diffraction effects in VHIS. Our approach can be applied to aperiodic, multiplexed gratings and used to theoretically predict the performance of multiplexed volume holographic gratings within a volume hologram for VHIS. We present simulation and experimental results for the aperiodic and multiplexed imaging gratings formed in PQ-PMMA at 488nm and probed with a spherical wave at 633nm. Simulation results based on our approach that can be easily implemented in ray-tracing packages such as Zemax® are confirmed with experiments and show proof of consistency and usefulness of the proposed models. PMID:20940823

Luo, Yuan; Castro, Jose; Barton, Jennifer K.; Kostuk, Raymond K.; Barbastathis, George

2010-01-01

33

Simulations and experiments of aperiodic and multiplexed gratings in volume holographic imaging systems.  

PubMed

A new methodology describing the effects of aperiodic and multiplexed gratings in volume holographic imaging systems (VHIS) is presented. The aperiodic gratings are treated as an ensemble of localized planar gratings using coupled wave methods in conjunction with sequential and non-sequential ray-tracing techniques to accurately predict volumetric diffraction effects in VHIS. Our approach can be applied to aperiodic, multiplexed gratings and used to theoretically predict the performance of multiplexed volume holographic gratings within a volume hologram for VHIS. We present simulation and experimental results for the aperiodic and multiplexed imaging gratings formed in PQ-PMMA at 488 nm and probed with a spherical wave at 633 nm. Simulation results based on our approach that can be easily implemented in ray-tracing packages such as Zemax® are confirmed with experiments and show proof of consistency and usefulness of the proposed models. PMID:20940823

Luo, Yuan; Castro, Jose; Barton, Jennifer K; Kostuk, Raymond K; Barbastathis, George

2010-08-30

34

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

35

Hidden-sector current-current correlators in holographic gauge mediation  

NASA Astrophysics Data System (ADS)

We discuss gauge mediation in the case where the hidden sector is strongly coupled but, via the gauge-gravity correspondence, admits a weakly-coupled description in terms of a warped higher-dimensional spacetime. In this framework, known as holographic gauge mediation, the visible-sector gauge group is realized in the gravitational description by probe D-branes and the nonsupersymmetric state by normalizable perturbations to the geometry. Using the formalism of general gauge mediation, supersymmetry-breaking soft terms in the visible sector can be related to the two-point functions of the hidden-sector current superfield that couples to the visible-sector gauge group. Such correlation functions cannot be directly calculated in the strongly coupled field theory but can be determined using the gauge-gravity correspondence and holographic renormalization. We explore this procedure by considering a toy geometry where such two-point functions can be explicitly calculated. Unlike previous implementations of holographic gauge mediation where sfermion masses were not calculable directly in a purely holographic framework, such terms are readily obtained via these correlators, while (due to the simplicity of the geometry considered) the visible-sector gauginos remain massless to leading order in the visible-sector coupling.

McGuirk, Paul

2012-02-01

36

Research of the file system of volume holographic storage based on virtual storage layer  

Microsoft Academic Search

Volume holographic storage (VHS) is currently the subject of widespread interest as a fast-readout-rate, high-capacity digital data-storage technology. To make need of characteristics of the VHS, the paper present the file system using a virtual storage layer (VSL) which can be compatible with the logic layer of the current used file system and accommodate the requirement of VHS in the

Fei Wu; Faling Yi; Changsheng Xie

2008-01-01

37

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

NASA Astrophysics Data System (ADS)

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; Yelin, S. F.

2011-09-01

38

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

39

Holographic volume gratings in dye-doped jelly-like gelatin  

NASA Astrophysics Data System (ADS)

Holographic characteristics of a thick self-developing photosensitive medium - dye-doped jelly-like gelatin are investigated by means of pulsed laser exposure. The experiments were performed using aqueous gelatin solutions of Rhodamin 6G with a layer thickness of 1 mm. The slanted holographic gratings were written with two crossed beams from a frequency-doubled (? = 532 nm) and Q-switched YAG:Nd laser (? 0.5 ~ 17 ns, f <= 50 Hz). In the course of recording the hologram was read with the beam from a single-mode He-Ne laser (? = 632.8 nm) which was not absorbed by the photosensitive medium. The real-time evolution of the grating diffraction efficiency was studied in dependence of the dye and gelatin concentration as well as the writing pulse fluence. It is shown that under appropriate choice of the medium composition and parameters of the recording radiation, it is possible to obtain phase volume holographic gratings with a diffraction efficiency of ~ 87 % and an angular selectivity of ~ 20'.

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

2007-06-01

40

Selective multimode excitation using volume holographic mode multiplexer.  

PubMed

We propose a mode multiplexer based on volume holograms to realize a simple and efficient mode-division-multiplexed transmission system that supports a large number of modes. Selective multiexcitation of three spatial modes into a conventional multimode fiber is experimentally demonstrated. This device could potentially multiplex 10 or more modes. Future perspectives of the mode multiplexer for application in mode-division multiplexing are also discussed. PMID:23455293

Aoki, Kohei; Okamoto, Atsushi; Wakayama, Yuta; Tomita, Akihisa; Honma, Satoshi

2013-03-01

41

Cryogenic tests of volume-phase holographic gratings: results at 100 K  

E-print Network

We present results from cryogenic tests of Volume-Phase Holographic(VPH) gratings at 100 K. The aims of these tests are to see whether the diffraction efficiency as a function of wavelength is significantly different at a low temperature from that at room temperature and to see how the performance of a VPH grating is affected by a number of thermal cycles. We have completed 10 cycles between room temperature and 100 $K$, and find no clear evidence that the diffraction efficiency changes with temperature or with successive thermal cycle.

Naoyuki Tamura; Graham J. Murray; Peter Luke; Colin Blackburn; David J. Robertson; Nigel A. Dipper; Ray M. Sharples; Jeremy R. Allington-Smith

2006-09-04

42

Volume displacement measurement via multi-wavelength digital holographic surface topography at the microscopic level  

NASA Astrophysics Data System (ADS)

In this work multiwavelength digital holography, originally applied to calculate the volume displacement of various macroscopic topographic surface features, is now extended to the case of microscopic objects. Accurate measurements of volume displacement for macroscopic surface features has been achieved using long synthetic wavelengths up to several millimeters, generated via tunable IR laser sources. Microscopic volume measurements are performed via digital holographic microscopy using HeNe and Ar+ ion lasers to generate very short synthetic wavelengths. Practical methods of implementation are considered, including wavelength selection error and the geometric effects of both Michelson and Mach-Zehnder recording configurations on phase measurement. Results include comparisons to standard metrology tools, including 1D profilometry and white light interferometry.

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

2014-02-01

43

Optimal resolution in Fresnel incoherent correlation holographic fluorescence microscopy  

PubMed Central

Fresnel Incoherent Correlation Holography (FINCH) enables holograms and 3D images to be created from incoherent light with just a camera and spatial light modulator (SLM). We previously described its application to microscopic incoherent fluorescence wherein one complex hologram contains all the 3D information in the microscope field, obviating the need for scanning or serial sectioning. We now report experiments which have led to the optimal optical, electro-optic, and computational conditions necessary to produce holograms which yield high quality 3D images from fluorescent microscopic specimens. An important improvement from our previous FINCH configurations capitalizes on the polarization sensitivity of the SLM so that the same SLM pixels which create the spherical wave simulating the microscope tube lens, also pass the plane waves from the infinity corrected microscope objective, so that interference between the two wave types at the camera creates a hologram. This advance dramatically improves the resolution of the FINCH system. Results from imaging a fluorescent USAF pattern and a pollen grain slide reveal resolution which approaches the Rayleigh limit by this simple method for 3D fluorescent microscopic imaging. PMID:21445140

Brooker, Gary; Siegel, Nisan; Wang, Victor; Rosen, Joseph

2011-01-01

44

Correlation between Voronoi volumes in disc packings  

E-print Network

We measure the two-point correlation of free Voronoi volumes in binary disc packings, where the packing fraction $\\phi_{\\rm avg}$ ranges from 0.8175 to 0.8380. We observe short-ranged correlations over the whole range of $\\phi_{\\rm avg}$ and anti-correlations for $\\phi_{\\rm avg}>0.8277$. The spatial extent of the anti-correlation increases with $\\phi_{\\rm avg}$ while the position of the maximum of the anti-correlation and the extent of the positive correlation shrink with $\\phi_{\\rm avg}$. We conjecture that the onset of anti-correlation corresponds to dilatancy onset in this system.

Song-Chuan Zhao; Stacy Sidle; Harry L. Swinney; Matthias Schröter

2011-09-05

45

Recording of incoherent reflective volume Fourier holograms for optical correlators  

NASA Astrophysics Data System (ADS)

The scheme of recording of reflective volume Fourier holograms in monochromatic light with partial spatial coherence is presented. The scheme contains posed on one optical axis an illuminated or self-luminous object, Fourier-objective, photosensitive medium and concave mirror. The light is proposed to be monochromatic with partial spatial coherence. The object is located in a front focal plane of the Fourier-objective. Photosensitive medium is placed in a back focal plane of the Fourier-objective, and the mirror is posed on a double focal length of the mirror from photosensitive medium. The light from input object is focused by the Fourier-objective in a volume of photosensitive medium, shaping a far field diffraction pattern of input object. This pattern is partial coherent analog of Fourier transform of input object. The light transmitted through the medium falls on the concave mirror and is reflected back, thus the mirror shapes the second copy of far field diffraction pattern of input object in the volume of photosensitive medium. Thus, these two light waves, propagating in the opposite directions, form the interference pattern in photosensitive medium, and a reflective volume Fourier hologram is recorded by monochromatic light with partial spatial coherence. The experiments on recording of these holograms and image reconstruction were realized. Patent by Russian Federation No2176099 on the device of recording of reflective volume holographic Fourier-filter in light with partial spatial coherence was taken out. Described reflective volume Fourier-holograms can be used in optical correlators as the spatial filters and spectral selectors at image recognition both in monochromatic and polychromatic light.

Rodin, Vladislav G.; Starikov, Sergey N.

2007-01-01

46

Pulse compression with volume holographic transmission gratings recorded in Slavich PFG-04 emulsion  

NASA Astrophysics Data System (ADS)

In this work we design and construct a pulse compressor with volume transmission holographic gratings, to compensate the second order dispersion in femtosecond laser pulses emitting at 794 nm with a spectral broadband of 10 nm. The gratings (730 lines/mm) are recorded in PFG-04 dichromated gelatine emulsion with a wavelength of 532 nm, reaching enough index modulation to use the gratings illuminated with 800 nm light source with high efficiency (around 80% of efficiency in each grating). This efficiency is expected to be increased with an antireflection coating. We measure the factor of compression as a function of the grating distance using an autocorrelator, finding a good agreement with theoretical curve. A dispersed pulse (580 fs) is reduced to the bandwidth limited value of 106 fs with the grating pair separated by 27 mm.

Villamarín, Ayalid; Sola, Íñigo; Atencia, J.; Collados, M. V.; Arias, I.; Mendez, C.; Varela, O.; Alonso, B.; Rodríguez, J.; Quintanilla, M.; Roso, L.

2009-08-01

47

Performance of volume phase holographic transmission grating recorded in DCG for PGP  

NASA Astrophysics Data System (ADS)

The volume phase holographic (VPH) transmission grating recorded in dichromate gelatin (DCG) with a specific spectral coverage from 420 nm to 760 nm is designed for a novel prism-grating-prism imaging spectrometer. Based on the Rigorous Coupled-Wave Analysis, its performances are predicted and analyzed. The grating is manufactured and its properties are measured experimentally. The diffraction efficiency over the spectral range, the bandwidth, and the angular selectivity of the grating is measured, analyzed and compared with that of the theoretical ones. The results show that by adjusting and controlling the preparation conditions of DCG plates, the exposure time and the post-processing technique of the grating, the VPH transmission grating with high diffraction efficiency approximate to the design requirement can be obtained. The measured peak diffraction efficiency reaches nearly 85% at central wavelength of 590 nm while the average diffraction efficiency is larger than 75% over the required spectral range from 420 nm to 760 nm.

Li, Ming; Tang, Minxue; Xia, Haohan; Fang, Chunhuan; Wu, Jianhong; Zhao, Xunjie

2010-11-01

48

Dual-grating confocal-rainbow volume holographic imaging system designs for high depth resolution.  

PubMed

Confocal microscopy rejects out-of-focus light from the object by scanning a pinhole through the image and reconstructing the image point by point. Volume holographic imaging systems with bright-field illumination have been proposed as an alternative to conventional confocal-type microscopes that does not require scanning of a pinhole or a slit. However, due to wavelength-position degeneracy of the hologram, the high Bragg selectivity of the volume hologram is not utilized and system performance is not optimized. Confocal-rainbow illumination has been proposed as a means to remove the degeneracy and improve optical sectioning in these systems. In prior work, two versions of this system were illustrated: the first version had a separate illumination and imaging grating and the second used a single grating to disperse the incident light and to separate wavelengths in the imaging path. The initial illustration of the dual-grating system has limited depth resolution due to the low selectivity of the illumination grating. The initial illustration of the single-grating system has high depth resolution but does not allow optimization of the illumination path and requires high optical quality of the holographic filters. In this paper we consider the design and tolerance requirements of the dual-grating system for high depth resolution and demonstrate the results with an experimental system. An experimental system with two 1.8 mm thick planar holograms achieved a depth resolution of 7 ?m with a field of view of 1.9 mm and a hologram dispersion matching tolerance of ±0.008°. PMID:23052072

de Leon, Erich E; Brownlee, Jonathan W; Gelsinger-Austin, Paul; Kostuk, Raymond K

2012-10-10

49

High-speed holographic correlation system by a time-division recording method for copyright content management on the internet  

NASA Astrophysics Data System (ADS)

Using a holographic disc memory on which a huge amount of data can be stored, we constructed an ultra-high-speed, all-optical correlation system. In this method, multiplex recording is, however, restricted to "one page" on "one spot." In addition, signal information must be normalized as data of the same size, even if the object data size is smaller. Therefore, this system is difficult to apply to part of the object data scene (i.e., partial scene searching and template matching), while maintaining high accessibility and programmability. In this paper, we develop a holographic correlation system by a time division recording method that increases the number of multiplex recordings on the same spot. Assuming that a four-channel detector is utilized, 15 parallel correlations are achieved by a time-division recording method. Preliminary correlation experiments with the holographic optical disc setup are carried out by high correlation peaks at a rotational speed of 300 rpm. We also describe the combination of an optical correlation system for copyright content management that searches the Internet and detects illegal contents on video sharing websites.

Watanabe, Eriko; Ikeda, Kanami; Kodate, Kashiko

2012-10-01

50

An investigation of the volume change associated with discharge of lithium\\/iodine batteries via holographic interferometric techniques  

Microsoft Academic Search

As part of an effort to delineate the rate-limiting mechanism in Li\\/Iâ (P2VP) batteries with pelletized cathodes, a holographic interferometric technique has been used to study the volume changes associated with the high rate discharge of these cells. This technique gives information on the changes in thickness of the hermetically sealed package, from which insights concerning the uniformity of, and

L. C. Phillips; R. G. Kelly; J. W. Wagner; P. J. Moran

1986-01-01

51

Compensation of second-order dispersion in femtosecond pulses after filamentation using volume holographic transmission gratings recorded in dichromated gelatin  

NASA Astrophysics Data System (ADS)

We have designed and developed a pulse compressor with volume transmission holographic gratings to be implemented in post-compression experiments based on filamentation in gases. Pulse compression down to 13 fs has been demonstrated. The gratings have been recorded in commercial PFG-04 dichromated gelatin emulsions with a recording wavelength of 532 nm, attaining sufficient index modulation to achieve high efficiency when they are illuminated by an 800-nm laser.

Villamarín, A.; Sola, I. J.; Collados, M. V.; Atencia, J.; Varela, O.; Alonso, B.; Méndez, C.; San Román, J.; Arias, I.; Roso, L.; Quintanilla, M.

2012-01-01

52

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

NASA Astrophysics Data System (ADS)

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 attracted a great deal of interest are the quark-gluon plasma, a plasma of strongly interacting quarks and gluons produced in relativistic heavy ion collisions, and ultracold atomic Fermi gases, very dilute clouds of atomic gases confined in optical or magnetic traps. These systems differ by 19 orders of magnitude in temperature, but were shown to exhibit very similar hydrodynamic flows. In particular, both fluids exhibit a robustly low shear viscosity to entropy density ratio, which is characteristic of quantum fluids described by holographic duality, a mapping from strongly correlated quantum field theories to weakly curved higher dimensional classical gravity. This review explores the connection between these fields, and also serves as an introduction to the focus issue of New Journal of Physics on ‘Strongly Correlated Quantum Fluids: From Ultracold Quantum Gases to Quantum Chromodynamic Plasmas’. The presentation is accessible to the general physics reader and includes discussions of the latest research developments in all three areas.

Adams, Allan; Carr, Lincoln D.; Schäfer, Thomas; Steinberg, Peter; Thomas, John E.

2012-11-01

53

Design of optical system for spectrometer involving a volume phase holographic transmission grating  

NASA Astrophysics Data System (ADS)

At present, spectrometer has popularly being used into varieties of fields including environment, food, medical health monitoring and metal industry because it has the advantages of noninvasive, high efficient and convenient etc. The performance of the spectrometer is determined by its optical system. Normally, according to the apparatus and principle of splitting-light, optical system of spectrometer can be classified into several categories, for example, filter-typed, dispersion typed, Fourier transform typed and acousto-optic tunable typed. The grating typed optical system has been popularly used into the spectrometer due to the features of higher diffraction efficiency, resolution and dispersion rate etc. In the grating-typed optical system, although the traditional plane and concave grating have usually been used into some spectrometers, some disadvantages of them still limit their applications, such as, large aberration, worse spectral flatness and low deficiency, etc. In this paper, to overcome these disadvantages of the traditional plane and concave grating, a novel optical system for spectrometer (OSS) based on volume phase holographic transmission (VPHT) grating was designed. For this novel grating, its manufacture and theories were investigated, and its diffraction efficiency was firstly numerically simulated according to different parameters. In order to prove the feasibility of this designed OSS, the spectral calibration experiment was performed and the spectral resolution reached 2nm.

Ren, Zhong; Liu, Guodong; Huang, Zhen

2014-08-01

54

Design and manufacture of transmission volume phase holographic grating used in VIS/NIR wave band  

NASA Astrophysics Data System (ADS)

Due to its uniform dispersion and higher diffraction efficiency, transmission volume phase holographic grating (VPHG) has been widely used for astronomical spectroscopy, ultrafast lasers compressors and wavelength division multiplexers. According to its application requirement and based on the Rigorous Coupled Wave Analysis (RCWA), a transmission VPHG with a frequency of 196lp/mm is designed and manufactured in this paper. The thickness of gelatin and the modulation of refraction index are optimized for high diffraction efficiency over a wavelength range from 420nm to 1000nm. The grating was recorded in dichromate gelatin (DCG) and in a symmetrical light path. By controlling the coating, exposure and post-processing conditions, the thickness of gelatin and the modulation of refraction index can be adjusted. The diffraction efficiency varied within the required wave band and the polarization property of the illumination wave were measured and compared with that of the theoretical ones. From the results, it can be seen that by adjusting and controlling the preparation conditions of DCG plates, the exposure value and post-processing technique, the peak diffraction efficiency of VPHG reaches to 47% and the average diffraction efficiency is above 35% in the spectral coverage, which is close to the theoretical values. This transmission VPHG can be applied in a prism-grating-prism (PGP) imaging spectrometer.

Fang, Chunhuan; Tang, Minxue; Wu, Jianhong

2011-11-01

55

New GRISMs for AFOSC based on volume phase holographic gratings in photopolymers  

NASA Astrophysics Data System (ADS)

Volume Phase Holographic Gratings (VPHG) can provide an improvement of diffraction efficiency and function- ality in already available astronomical instrumentation. Here, we present the design, manufacturing and testing of two GRISMs mounted on the AFOSC camera (at the 1.8 m Asiago telescope) based on VPHGs. Such diffrac- tion gratings have been written on a new solid and green sensitive photopolymer material produced by Bayer MaterialScience AG that show interesting performances (refractive index modulation, homogeneity, stability). The GRISMs have been designed according to the specific requests of astronomers. One GRISM consists in a very low dispersion VPHG (285 l/mm) that covers the range 500 - 1000 nm and suitable for observations of supernovae. The second one is a 600 l/mm VPHG for the Ha region. Both gratings show peak efficiency close to 90% and same diffraction efficiency is shown by the corresponding GRISMs. This high device's performances means that the coupling losses are very low, also thanks to the matching of the refractive index between sub- strates and prisms. Some observations have been finally carried out and the gain in terms of efficiency and signal to noise ratio have been calculated in order to compare the photopolymeric VPHGs with the classic GRISMs already mounted and used in the AFOSC spectrometer.

Zanutta, Alessio; Bianco, Andrea; Landoni, Marco; Tomasella, Lina; Benetti, Stefano; Giro, Enrico

2014-07-01

56

The Infrared Imaging Spectrograph (IRIS) for TMT: Volume phase holographic grating performance testing and discussion  

E-print Network

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{\\mu}m (H-band) to produce a spectral resolution of 4000 and 1.19- 1.37 {\\mu}m (J-band) to produce a spectral resolution of 8000....

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

2014-01-01

57

Periodical energy oscillation and pulse splitting in sinusoidal volume holographic grating.  

PubMed

This paper presents dynamical diffraction properties of a femtosecond pulse in a sinusoidal volume holographic grating (VHG). By the modified coupled-wave equations of Kogelnik, we show that the diffraction of a femtosecond pulse on the VHG gives rise to periodical energy oscillation and pulse splitting. In the initial stage of diffraction, one diffracted pulse and one transmitted pulse emerge, and energy of the transmitted pulse periodically transfers to the diffracted pulse and vice versa. In the latter stage, both the diffracted and transmitted pulses split into two spatially separated pulses. One pair of transmitted and diffracted pulses propagates in the same direction and forms the output diffracted dual pulses of the VHG, and the other pair of pulses forms the output transmitted dual pulses. The pulse interval between each pair of dual pulses is in linearly proportional to the refractive index modulation and grating thickness. By the interference effect and group velocity difference we give explanations on the periodical energy oscillation and pulse splitting respectively. PMID:25089472

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

2014-07-28

58

Mass production of volume phase holographic gratings for the VIRUS spectrograph array  

NASA Astrophysics Data System (ADS)

The Visible Integral-field Replicable Unit Spectrograph (VIRUS) is a baseline array of 150 copies of a simple, fiber-fed integral field spectrograph that will be deployed on the Hobby-Eberly Telescope (HET). VIRUS is the first optical astronomical instrument to be replicated on an industrial scale, and represents a relatively inexpensive solution for carrying out large-area spectroscopic surveys, such as the HET Dark Energy Experiment (HETDEX). Each spectrograph contains a volume phase holographic (VPH) grating with a 138 mm diameter clear aperture as its dispersing element. The instrument utilizes the grating in first-order for 350 < ? (nm) < 550. Including witness samples, a suite of 170 VPH gratings has been mass produced for VIRUS. Here, we present the design of the VIRUS VPH gratings and a discussion of their mass production. We additionally present the design and functionality of a custom apparatus that has been used to rapidly test the first-order diffraction efficiency of the gratings for various discrete wavelengths within the VIRUS spectral range. This device has been used to perform both in-situ tests to monitor the effects of adjustments to the production prescription as well as to carry out the final acceptance tests of the gratings' diffraction efficiency. Finally, we present the as-built performance results for the entire suite of VPH gratings.

Chonis, Taylor S.; Frantz, Amy; Hill, Gary J.; Clemens, J. Christopher; Lee, Hanshin; Tuttle, Sarah E.; Adams, Joshua J.; Marshall, J. L.; DePoy, D. L.; Prochaska, Travis

2014-07-01

59

Research of the file system of volume holographic storage based on virtual storage layer  

NASA Astrophysics Data System (ADS)

Volume holographic storage (VHS) is currently the subject of widespread interest as a fast-readout-rate, high-capacity digital data-storage technology. To make need of characteristics of the VHS, the paper present the file system using a virtual storage layer (VSL) which can be compatible with the logic layer of the current used file system and accommodate the requirement of VHS in the physical layer. The VSL which is made of the super block, directory area, the metadata area and dynamic file area can connect directly to the storage media one side and implement compatible to the existing file system by providing the operating interfaces for the above logical file system. We produce the two layer storage structure which effectively reduces the number of disk accessed and improves the speed of file read and write. The allocation mode of 'hybrid of block and zone' and allocation strategy of 'block priority' greatly improve the space utilization rate of storage device and enforce the storage adaptability in VHS.

Wu, Fei; Yi, Faling; Xie, Changsheng

2008-02-01

60

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

61

Methods for evaluating the performance of volume phase holographic gratings for the VIRUS spectrograph array  

NASA Astrophysics Data System (ADS)

The Visible Integral field Replicable Unit Spectrograph (VIRUS) is an array of at least 150 copies of a simple, fiber-fed integral field spectrograph that will be deployed on the Hobby-Eberly Telescope (HET) to carry out the HET Dark Energy Experiment (HETDEX). Each spectrograph contains a volume phase holographic grating as its dispersing element that is used in first order for 350 < ?(nm) < 550. We discuss the test methods used to evaluate the performance of the prototype gratings, which have aided in modifying the fabrication prescription for achieving the specified batch diffraction efficiency required for HETDEX. In particular, we discuss tests in which we measure the diffraction efficiency at the nominal grating angle of incidence in VIRUS for all orders accessible to our test bench that are allowed by the grating equation. For select gratings, these tests have allowed us to account for < 90% of the incident light for wavelengths within the spectral coverage of VIRUS. The remaining light that is unaccounted for is likely being diffracted into reflective orders or being absorbed or scattered within the grating layer (for bluer wavelengths especially, the latter term may dominate the others). Finally, we discuss an apparatus that will be used to quickly verify the first order diffraction efficiency specification for the batch of at least 150 VIRUS production gratings.

Chonis, Taylor S.; Hill, Gary J.; Clemens, J. Christopher; Dunlap, Bart; Lee, Hanshin

2012-09-01

62

Review of three-dimensional holographic imaging by Fresnel incoherent correlation holograms  

Microsoft Academic Search

Holographic imaging offers a reliable and fast method to capture the complete 3-D information of the scene from a single perspective.\\u000a We review our recently proposed single-channel optical system for generating digital Fresnel holograms of 3-D real-existing\\u000a objects illuminated by incoherent light. In this motionless holographic technique, light is reflected, or emitted, from a\\u000a 3-D object, propagates through a spatial

Joseph Rosen; Barak Katz; Gary Brooker

2010-01-01

63

Review of Three-Dimensional Holographic Imaging by Fresnel Incoherent Correlation Holograms  

Microsoft Academic Search

Holographic imaging offers a reliable and fast method to capture the complete 3-D information of the scene from a single perspective. We review our recently proposed single-channel optical system for generating digital Fresnel holograms of 3-D real-existing objects illuminated by incoherent light. In this motionless holographic technique, light is reflected, or emitted, from a 3-D object, propagates through a spatial

Joseph Rosen; Barak Katz; Gary Brooker

2009-01-01

64

Volume 96. number 5 CHEMICAL PHYSICS LETTERS 8 July 1983 HOLOGRAPHIC GENE&Vi-ION OF BUBBLE GRATINGS AT LIQUID-GLASS INTERFACES  

E-print Network

Volume 96. number 5 CHEMICAL PHYSICS LETTERS 8 July 1983 HOLOGRAPHIC GENE&Vi-ION OF BUBBLE GRATINGS-2614/83/0000-0000/S 03.00 0 1983 North-Holland #12;Volume 98, number 5 CHEMICAL PHYSICS LETTERS 8 July. 1983 are generated by 100 ps, 1.06 tin, pulses from .I Nd : YAG laser which are crossed at a liquid

Fayer, Michael D.

65

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

66

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

67

High-speed Reed-Solomon decoder using reformulation inversionless Berlekamp-Massey architecture for volume holographic storage  

NASA Astrophysics Data System (ADS)

Volume holography is currently the subject of widespread interest as a fast-readout-rate, high-capacity digital data-storage technology. However, due to the effect of cross-talk noise, scattering noise, noise gratings formed during a multiple exposure schedule, it brings a lot of burst errors and random errors in the system. Reed-Solomon error-correction codes have been widely used to defend digital data against errors, but the speed of Reed-Solomon decoder for volume holographic storage system application is a challenge. This paper presents a high-speed VLSI decoder architecture implementation for decoding (255,223) Reed-Solomon codes with the Modified Berlekamp-Massey algorithm for volume holographic storage. In contrast to conventional Berlekamp-Massey architectures, the speed bottleneck is eliminated via a series of algorithmic transformations that result in a fully systolic architecture in which a single array of processors computes both the error-locator and the error-evaluator polynomials. The proposed architecture requirs approximately 25% fewer multipliers and a simpler control structure than the architectures based on the popular extended Euclidean algorithm. By adopting high speed CPLD, a data processing rate over 200 Mbit/s is realized. Moreover, for block-interleaved Reed-Solomon codes, embedding the interleaver memory into the decoder results in a further increase of the throughput.

Hu, Diqing; Xie, Changsheng

2003-04-01

68

Conically Scanned Holographic LIDAR Telescope  

NASA Technical Reports Server (NTRS)

Holographic LIDAR telescope includes holographic disk, rotation of which sweeps collimated, monochromatic beam of light from laser through conical scan. Holographic disk diffracts light scattered back from target volume or area to focal point located at stationary photomultiplier detector. Two conical baffles prevent stray light from reaching detector.

Schwemmer, Geary

1993-01-01

69

Time-sequential autostereoscopic 3-D display with a novel directional backlight system based on volume-holographic optical elements.  

PubMed

A novel directional backlight system based on volume-holographic optical elements (VHOEs) is demonstrated for time-sequential autostereoscopic three-dimensional (3-D) flat-panel displays. Here, VHOEs are employed to control the direction of light for a time-multiplexed display for each of the left and the right view. Those VHOEs are fabricated by recording interference patterns between collimated reference beams and diverging object beams for each of the left and right eyes on the volume holographic recording material. For this, self-developing photopolymer films (Bayfol® HX) were used, since those simplify the manufacturing process of VHOEs substantially. Here, the directional lights are similar to the collimated reference beams that were used to record the VHOEs and create two diffracted beams similar to the object beams used for recording the VHOEs. Then, those diffracted beams read the left and right images alternately shown on the LCD panel and form two converging viewing zones in front of the user's eyes. By this he can perceive the 3-D image. Theoretical predictions and experimental results are presented and the performance of the developed prototype is shown. PMID:24787867

Hwang, Yong Seok; Bruder, Friedrich-Karl; Fäcke, Thomas; Kim, Seung-Cheol; Walze, Günther; Hagen, Rainer; Kim, Eun-Soo

2014-04-21

70

Polarization of holographic grating diffraction. II. Experiment.  

PubMed

The transmittance, ellipsometric parameters, and depolarization of transmission, diffraction, and reflection of two volume holographic gratings (VHGs) are measured at a wavelength of 632.8 nm. The measured data are in good agreement with the theoretical simulated results, which demonstrated the correlation between the diffraction strength and the polarization properties of a VHG. Vector electromagnetic theory and polarization characterization are necessary for complete interpretation of the diffraction property of a VHG. The diffraction efficiency is measured at 532 nm in a polarization-sensing experiment. The measured data and theoretical simulation have demonstrated the potential application of the holographic beam splitter for polarization-sensor technology. PMID:15078024

Nee, Tsu-Wei; Nee, Soe-Mie F; Kleinschmit, Mark W; Shahriar, M S

2004-04-01

71

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

72

Cross-talk in phase encoded volume holographic memories employing unitary matrices  

Microsoft Academic Search

The cross-talk noise in phase encoded holographic memories employing unitary matrices is theoretically investigated. After reviewing some earlier work in this area, we derive a relationship for the noise-to-signal ratio for phase-code multiplexing with unitary matrices. The noise-to-signal ratio rises in a zigzag way on increasing the storage capacity. Cross-talk is mainly caused by high-frequency phase codes. Unitary matrices of

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

2006-01-01

73

High-accuracy measurement of depth-displacement using a focus function and its cross- correlation in holographic PTV.  

PubMed

We propose a method using a focus function and its cross-correlation to measure depth-position and precise depth-displacement. The focus function provides acceptable results in the determination of depth-position of a transparent particle, an opaque particle, and a red blood cell. However, positional errors and a short time interval can cause unreliable results in identifying depth-displacement (?z) and depth-directional velocity in digital holographic particle tracking velocimetry (DHPTV). To minimize the errors in ?z, we propose a method that directly obtains depth displacement from the cross-correlation of focus values between consecutive holograms. The feasibility of this method is demonstrated by quantitatively visualizing a 3D flow using HPTV. PMID:24977812

Seo, Kyung Won; Lee, Sang Joon

2014-06-30

74

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

E-print Network

The Prime Focus Spectrograph (PFS) is a major instrument under development for the 8.2 m Subaru telescope. Four identical spectrograph modules are located in a room above one Nasmyth focus. A 55~m fiber optic cable feeds light to the spectrographs from a robotic positioner at the 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. The spectrograph optical design consists of a Schmidt collimator, two dichroic beamsplitters to split 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~\\textmu m, and good imaging performance at the fast f/1.05 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 co...

Barkhouser, Robert; Gunn, James E

2014-01-01

75

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

76

A floating type holographic display.  

PubMed

A floating image type holographic display which projects an electronically generated holographic image together with a background image displayed on a monitor/TV to enhance the visual effects of the former image is introduced. This display can display a holographic image with a spatial volume floating in the front space of the display with use of PDLC sheets as the focused plane of the image. This display can preserve and enhance the main property of holographic image from a display chip, i.e., a spatial image with a volume. This property had not been appealed by the previous holographic displays due to the much brighter active surface image accompanied with the reconstructed image and the diffuser used for viewing the image. PMID:24105588

Son, Jung-Young; Lee, Chun-Hae; Chernyshov, Oleksii O; Lee, Beom-Ryeol; Kim, Sung-Kyu

2013-08-26

77

Regional White Matter Volumes Correlate with Delay Discounting  

PubMed Central

A preference for immediate gratification is a central feature in addictive processes. However, the neural structures underlying reward delay tolerance are still unclear. Healthy participants (n?=?121) completed a delay discounting questionnaire assessing the extent to which they prefer smaller immediate rewards to larger delayed reward after undergoing magnetic resonance imaging (MRI) scanning. Whole brain voxel-based morphometric analysis shows that delay discounting severity was negatively correlated with right prefrontal subgyral white matter volume and positively correlated with white matter volume in parahippocampus/hippocampus, after whole brain correction. This study might better our understanding of the neural basis of impulsivity and addiction. PMID:22393420

Yu, Rongjun

2012-01-01

78

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

79

Volume holographic image storage and electro-optical readout in a polymer-dispersed liquid-crystal film  

NASA Astrophysics Data System (ADS)

We report storage and electrical switching of holographic image data in an economical polymer-dispersed liquid-crystal material. The hologram is recorded in a fast, single-step process and can be reversibly erased and restored repeatedly by the application of fields of approximately 10-15 V / mu m , with a response time of 22 mu s and a relaxation time of 42 mu s . Simple (quasi-sinusoidal) holographic transmission gratings also are studied with switching fields of <5 V / mu m and with response and relaxation times of 25 and 44 mu s , respectively.

Tondiglia, V. P.; Natarajan, L. V.; Sutherland, R. L.; Bunning, T. J.; Adams, W. W.

1995-06-01

80

Cross-correlations between volume change and price change  

E-print Network

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 $\\tilde R$, 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 $|\\tilde R|$, and their relationship to price changes $|R|$. We analyze $14,981$ daily recordings of the S\\&P 500 index over the 59-year period 1950--2009, and find power-law {\\it cross-correlations\\/} between $|R|$ and $|\\tilde R|$ using detrended cross-correlation analysis (DCCA). We introduce a joint stochastic process that models these cross-correlations. Motivated by the relationship between $| R|$ and $|\\tilde R|$, we estimate the tail exponent ${\\tilde\\alpha}$ of the probability density function $P(|\\tilde R|) \\sim |\\tilde R|^{-1 -\\tilde\\alpha}$ for both the S\\&P 500 index as well as the collection of 1819 consti...

Podobnik, Boris; Petersen, Alexander M; Stanley, H Eugene; 10.1073/pnas.0911983106

2010-01-01

81

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

82

Cross-correlations between volume change and price change  

PubMed Central

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 ?? of the probability density function P(|R?|) ? |R?|?1??? 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 ??, we calculate the time intervals ?q between events where R? > q. We demonstrate that ??q, the average of ?q, obeys ??q ? q??. We find ?? ? 3. Furthermore, by aggregating all ?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

2009-01-01

83

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

84

Defect Tolerance of an Optically Reconfigurable Gate Array with a One-time Writable Volume Holographic Memory  

Microsoft Academic Search

Optically reconfigurable gate arrays (ORGAs) have been developed as a type of multi-context field programmable gate array to realize fast reconfiguration and numerous reconfiguration contexts. Along with such advantages, ORGAs have high defect tolerance. They consist simply of a holographic memory, a laser diode array, and a gate array VLSI. Even if a gate array VLSI includes defective areas, the

Takayuki Mabuchi; Kenji Miyashiro; M. Watanabe; A. Ogiwara

2009-01-01

85

Holographic interferometry.  

NASA Technical Reports Server (NTRS)

Review of the techniques and applications of holographic interferometry. The recording of a 'reflected-light' hologram with a gas laser is described in order to illustrate the unique optical properties of a hologram. Special types of interferometric measurement, such as stored-beam holographic interferometry and double-exposure holographic interferometry, are then discussed. Applications of gas-laser holographic interferometry to the detection of internal flaws in steel tubing are cited, as well as applications involving the testing of aircraft and automotive tires and aircraft honeycomb composites for bond integrity and the prediction of failure in mechanical components. Finally, applications of the pulsed solid-state ruby laser in holographic interferometry are considered.

Wuerker, R. F.

1972-01-01

86

Measurement of absolute cell volume, osmotic membrane water permeability, and refractive index of transmembrane water and solute flux by digital holographic microscopy  

NASA Astrophysics Data System (ADS)

A dual-wavelength digital holographic microscope to measure absolute volume of living cells is proposed. The optical setup allows us to reconstruct two quantitative phase contrast images at two different wavelengths from a single hologram acquisition. When adding the absorbing dye fast green FCF as a dispersive agent to the extracellular medium, cellular thickness can be univocally determined in the full field of view. In addition to the absolute cell volume, the method can be applied to derive important biophysical parameters of living cells including osmotic membrane water permeability coefficient and the integral intracellular refractive index (RI). Further, the RI of transmembrane flux can be determined giving an indication about the nature of transported solutes. The proposed method is applied to cultured human embryonic kidney cells, Chinese hamster ovary cells, human red blood cells, mouse cortical astrocytes, and neurons.

Boss, Daniel; Kühn, Jonas; Jourdain, Pascal; Depeursinge, Christian; Magistretti, Pierre J.; Marquet, Pierre

2013-03-01

87

An Analytic Holographic Superconductor  

E-print Network

We investigate a holographic superconductor that admits an analytic treatment near the phase transition. In the dual 3+1 dimensional field theory, the phase transition occurs when a scalar operator of scaling dimension two gets a vacuum expectation value. We calculate current-current correlation functions along with the speed of second sound near the critical temperature. We also make some remarks about critical exponents. An analytic treatment is possible because an underlying Heun equation describing the zero mode of the phase transition has a polynomial solution. Amusingly, the treatment here may generalize for an order parameter with any integer spin, and we propose a Lagrangian for a spin two holographic superconductor.

Christopher P. Herzog

2010-03-17

88

Holographic movies  

Microsoft Academic Search

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

Joseph C. Palais; Mark E. Miller

1996-01-01

89

Intelligent holographic databases  

NASA Astrophysics Data System (ADS)

Memory is a key component of intelligence. In the human brain, physical structure and functionality jointly provide diverse memory modalities at multiple time scales. How could we engineer artificial memories with similar faculties? In this thesis, we attack both hardware and algorithmic aspects of this problem. A good part is devoted to holographic memory architectures, because they meet high capacity and parallelism requirements. We develop and fully characterize shift multiplexing, a novel storage method that simplifies disk head design for holographic disks. We develop and optimize the design of compact refreshable holographic random access memories, showing several ways that 1 Tbit can be stored holographically in volume less than 1 m3, with surface density more than 20 times higher than conventional silicon DRAM integrated circuits. To address the issue of photorefractive volatility, we further develop the two-lambda (dual wavelength) method for shift multiplexing, and combine electrical fixing with angle multiplexing to demonstrate 1,000 multiplexed fixed holograms. Finally, we propose a noise model and an information theoretic metric to optimize the imaging system of a holographic memory, in terms of storage density and error rate. Motivated by the problem of interfacing sensors and memories to a complex system with limited computational resources, we construct a computer game of Desert Survival, built as a high-dimensional non-stationary virtual environment in a competitive setting. The efficacy of episodic learning, implemented as a reinforced Nearest Neighbor scheme, and the probability of winning against a control opponent improve significantly by concentrating the algorithmic effort to the virtual desert neighborhood that emerges as most significant at any time. The generalized computational model combines the autonomous neural network and von Neumann paradigms through a compact, dynamic central representation, which contains the most salient features of the sensory inputs, fused with relevant recollections, reminiscent of the hypothesized cognitive function of awareness. The Declarative Memory is searched both by content and address, suggesting a holographic implementation. The proposed computer architecture may lead to a novel paradigm that solves 'hard' cognitive problems at low cost.

Barbastathis, George

90

Holographic microrefractometer  

NASA Astrophysics Data System (ADS)

In-line holographic microscopy of micrometer-scale colloidal spheres yields heterodyne scattering patterns that may be interpreted with Lorenz-Mie theory to obtain precise time-resolved information on the refractive index of the suspending medium. We demonstrate this approach to spatially resolved refractometry with measurements on calibrated refractive index standards and use it to monitor chemical concentration in a microfluidic channel. Using commercially available colloidal spheres as probe particles and a standard video camera for detection yields values for the fluid's refractive index at the position of each probe particle in each holographic snapshot with a demonstrated resolution of 2×10-3 refractive index units (RIU) and a potential resolution surpassing 10-4 RIU. The combination of spatial resolution, temporal resolution, multi-point in situ access, and technical simplicity recommends this technique for cost-effective lab-on-a-chip applications.

Shpaisman, Hagay; Jyoti Krishnatreya, Bhaskar; Grier, David G.

2012-08-01

91

Volume-Energy Correlations in the Slow Degrees of Freedom of Computer-Simulated Phospholipid Membranes  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations of phospholipid membranes reveals striking correlations between equilibrium fluctuations of volume and energy on the nanosecond time-scale. Volume-energy correlations have previously been observed experimentally at the phase transition between the L? phase and the L? phase, but not in the fluid L? phase. The correlations are investigated in four membranes, with correlation coefficients ranging between 0.81 and 0.89. An experimentally single parameter test is proposed.

Pedersen, Ulf R.; Peters, Günther H.; Schrøder, Thomas B.; Dyre, Jeppe C.

2008-02-01

92

Holographic Spacetime  

NASA Astrophysics Data System (ADS)

The theory of holographic spacetime (HST) generalizes both string theory and quantum field theory (QFT). It provides a geometric rationale for supersymmetry (SUSY) and a formalism in which super-Poincare invariance follows from Poincare invariance. HST unifies particles and black holes, realizing both as excitations of noncommutative geometrical variables on a holographic screen. Compact extra dimensions are interpreted as finite-dimensional unitary representations of super-algebras, and have no moduli. Full field theoretic Fock spaces, and continuous moduli are both emergent phenomena of super-Poincare invariant limits in which the number of holographic degrees of freedom goes to infinity. Finite radius de Sitter (dS) spaces have no moduli, and break SUSY with a gravitino mass scaling like ?1/4. In regimes where the Covariant Entropy Bound is saturated, QFT is not a good description in HST, and inflation is such a regime. Following ideas of Jacobson, the gravitational and inflaton fields are emergent classical variables, describing the geometry of an underlying HST model, rather than "fields associated with a microscopic string theory". The phrase in quotes is meaningless in the HST formalism, except in asymptotically flat and AdS spacetimes, and some relatives of these.

Banks, Tom

2012-10-01

93

Correlations between Regional Brain Volumes and Memory Performance in Anoxia  

Microsoft Academic Search

This study was aimed at investigating the quantitative relationship between regional brain volumes (hippocampus, amygdala, as well as cerebrum, frontal lobe, parietal lobe, temporal lobe) and performance on anterograde and retrograde memory tests in anoxic patients. We used high-resolution MRI to measure brain volumes in 13 anoxic patients. Neuropsychological testing was conducted contemporaneously with MRI. To control for age and

John S. Allen; Daniel Tranel; Joel Bruss; Hanna Damasio

2006-01-01

94

Regional Brain Volumes and Their Later Neurodevelopmental Correlates in Term and Preterm Infants  

E-print Network

groups. Measures of cognitive and motor develop- ment were acquired between 18 and 20 months of corRegional Brain Volumes and Their Later Neurodevelopmental Correlates in Term and Preterm Infants infants, and to correlate regional volumes with measures of neurodevel- opmental outcome. Methods. High

95

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

96

Holographic thermalization patterns  

E-print Network

We investigate the behaviour of various correlators in N=4 super Yang Mills theory, taking finite coupling corrections into account. In the thermal limit we investigate the flow of the quasinormal modes as a function of the 't Hooft coupling. Then by using a specific model of holographic thermalization we investigate the deviation of the spectral densities from their thermal limit in an out-of-equilibrium situation. The main focus lies on the thermalization pattern with which the various plasma constituents of different energies approach their final thermal distribution as the coupling constant decreases from the infinite coupling limit. All results point towards the weakening of the usual top down thermalization pattern.

Stefan Stricker

2014-03-11

97

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

98

Holographic Gratings for Optical Processing  

NASA Technical Reports Server (NTRS)

Investigation of astronomical objects and tracking of man-made space objects lead to generation of huge amount of information for optical processing. Traditional big-size optical elements (such as optical telescopes) have a tendency for increasing aperture size in order to improve sensitivity. This tendency leads to increasing of weight and costs of optical systems and stimulate search for the new, more adequate technologies. One approach to meet these demands is based on developing of holographic optical elements using new polymeric materials. We have investigated possibility to use new material PQ-PMMA (phenantrenequinone-doped PMMA (Polymethyl Methacrylate)) for fabrication of highly selective optical filters and fast spatial-temporal light modulators. This material was originally developed in Russia and later was tested in CalTech as a candidate material for optical storage. Our theoretical investigation predicts the possibility of realization of fast spatial and temporal light modulation, using volume reflection-type spectral filter. We have developed also model of holographic-grating recording in PQ-PMMA material, based on diffusional amplification. This mechanism of recording allow to receive high diffraction efficiency during recording of reflection-type volume holographic grating (holographic mirror). We also investigated recording of dynamic gratings in the photorefractive crystals LiNbO3 (LN) for space-based spectroscopy and for adaptive correction of aberrations in the telescope's mirrors. We have shown, that specific 'photogalvanic' mechanism of holographic grating recording in LN allow to realize recording of blazed gratings for volume and surface gratings. Possible applications of dynamic gratings in LN for amplification of images, transmitted through an imaging fiber guide was also demonstrated.

Kukhtarev, Nickolai

2002-01-01

99

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

100

Holographic interferometry.  

PubMed

Since its inception three decades ago, holographic interferometry has proven to be a powerful nondestructive testing technique for the measurement of displacement and its derivatives. It is a whole-field, noncontact method which requires the use of a hologram to record three-dimensional information about the surface of an object. After a stress is applied to the object, its new surface geometry is compared with the previously recorded state. Changes of the surface of the object, which are manifest as a series of interference fringes superimposed on the image of the object, can be observed statically or in real time to reveal the displacement. Current state-of-the-art techniques such as heterodyne and digital phase shifting interferometry, which have extended the resolution of holographic interferometry far beyond fringe counting, are reviewed. Particular emphasis is placed upon applications in biomedical engineering and medicine, although potentially applicable techniques from other disciplines are examined. The paper is broken into two main parts. In the first part, the scope and potential limitations of this branch of metrology are presented. In the second part, a review of applications in biomedical engineering is presented. The references cited in the first section are the seminal papers in the field. The applications section, which relies upon the results of the first section, presents a critical review of the literature by analyzing the results of a few representative studies. PMID:2646067

Ovryn, B

1989-01-01

101

Recording of incoherent reflective volume Fourier holograms for optical correlators  

Microsoft Academic Search

The scheme of recording of reflective volume Fourier holograms in monochromatic light with partial spatial coherence is presented. The scheme contains posed on one optical axis an illuminated or self-luminous object, Fourier-objective, photosensitive medium and concave mirror. The light is proposed to be monochromatic with partial spatial coherence. The object is located in a front focal plane of the Fourier-objective.

Vladislav G. Rodin; Sergey N. Starikov

2007-01-01

102

The Effects of Varying the Correlation Volume on Strangeness Production in High Energy Collisions  

E-print Network

Preliminary results on strange particle production versus collision centrality are presented. STAR measurements from \\sqrts = 200 GeV heavy-ion and \\pp collisions are compared to SPS measurements. A systematic study of strange particle production is presented with the aim of establishing how the correlation volume of the produced source affects the scale of strange particle creation, including that of the multi-strange baryons. A linear increase of strangeness production with volume has been suggested by thermal models as an indication that the collision region has reached sufficient size such that small volume effects can be neglected. Analysis of preliminary results from STAR show that, using the assumption that the number of participants is linearly correlated with the volume, no such regime was obtained. This suggests that the correlation volume ''seen" by strange quarks is not merely that of the initial overlap.

Helen Caines

2006-01-10

103

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.

Shingo Takeuchi

2013-09-22

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

Numerical modeling of shift multiplexed holographic data storage  

Microsoft Academic Search

In this paper, we present a numerical modeling of shift multiplexed holographic data storage that can efficiently provide these parameters for transmissive or reflective gratings as well. The electromagnetic volume integral of perturbative scattering theory, can be used to simulate the holographic diffraction of weakly modulated finite sized gratings generated by the interference of a high NA wide-angle spherical beam

B. Gombkoto; P. Koppa; E. Lorincz; A. Suto

2007-01-01

106

Computer Generated Holographic Optics.  

National Technical Information Service (NTIS)

The goal of this research was to theoretically and experimentally investigate the use of computer-generated holograms in the design and fabrication of holographic optical elements (holographic lenses or diffraction optics). Conventional design of holograp...

J. R. Fienup

1980-01-01

107

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

2007-06-08

108

Correlation between MR imaging-derived nasopharyngeal carcinoma tumor volume and TNM system  

SciTech Connect

Purpose: To measure nasopharyngeal carcinoma tumor volume based on magnetic resonance images using a validated semiautomated measurement methodology and correlate tumor volume with TNM T classification. Methods and Materials: The study population consisted of 206 consecutive nasopharyngeal carcinoma patients who had magnetic resonance imaging staging scans. Tumor volume was measured using a semisupervised knowledge-based fuzzy clustering algorithm. Patients were divided into 4 groups according to TNM T classification. The difference in tumor volumes among the various TNM T-classification groups was examined. Results: The mean tumor volume in each T-classification group is as follows: T1, 8.6 mL {+-} 5.0 (standard deviation [SD]); T2, 18.1 mL {+-} 8.1 (SD); T3, 25.8 mL {+-} 14.1 (SD); and T4, 36.2 mL {+-} 18.9 (SD). The mean tumor volume increased significantly with advancing T classification (p < 0.0001). Tumor volume in a more advanced T group was significantly larger than that in an adjacent early T group (p < 0.01). Conclusion: Validated magnetic resonance imaging-based tumor volume shows positive correlation between tumor volume and advancing T-classification groups. It may be possible to incorporate tumor volume as an additional prognostic factor into the existing TNM system.

Chong, Vincent F.H. [Department of Diagnostic Radiology, Faculty of Medicine, National University of Singapore, Singapore (Singapore)]. E-mail: dnrcfhv@nus.edu.sg; Zhou, J.-Y. [Biomedical Engineering Research Centre, Nanyang Technological University, Singapore (Singapore); Khoo, James B.K. [Department of Oncologic Imaging, National Cancer Centre, Singapore (Singapore); Chan, K.-L. [Biomedical Engineering Research Centre, Nanyang Technological University, Singapore (Singapore); Huang Jing [Department of Oncologic Imaging, National Cancer Centre, Singapore (Singapore)

2006-01-01

109

Yet on statistical properties of traded volume: Correlation and mutual information at different value magnitudes  

NASA Astrophysics Data System (ADS)

In this article we analyse linear correlation and non-linear dependence of traded volume, v, of the 30 constituents of Dow Jones Industrial Average at different value scales. Specifically, we have raised v to some real value ? or ?, which introduces a bias for small (?, ?<0) or large (?, ?>1) values. Our results show that small values of v are regularly anti-correlated with values at other scales of traded volume. This is consistent with the high liquidity of the 30 equities analysed and the asymmetric form of the multi-fractal spectrum for traded volume which has supported the dynamical scenario presented by us.

Duarte Queirós, S. M.; Moyano, L. G.

2007-09-01

110

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

111

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

PubMed Central

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. PMID:24336512

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

2013-01-01

112

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

113

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

2014-04-23

114

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

115

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

116

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

2014-01-14

117

Holographic MQCD  

SciTech Connect

We study a brane configuration of D4-branes and NS5-branes in weakly coupled type IIA string theory, which describes in a particular limit d=4 N=1 SU(N+p) supersymmetric QCD with 2N flavors and a quartic superpotential. We describe the geometric realization of the supersymmetric vacuum structure of this gauge theory. We focus on the confining vacua of the gauge theory, whose holographic description is given by the MQCD brane configuration in the near-horizon geometry of N D4-branes. This description, which gives an embedding of MQCD into a field theory decoupled from gravity, is valid for 1<

Aharony, Ofer [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel); Kutasov, David [EFI and Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Lunin, Oleg [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States); Sonnenschein, Jacob; Yankielowicz, Shimon [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 69978 (Israel); Albert Einstein Minerva Center, Weizmann Institute of Science, Rehovot 76100 (Israel)

2010-11-15

118

Some New Applicational Possibilities of Holograph.  

National Technical Information Service (NTIS)

The report discusses possible applications of holography in the following areas: Holographic mass storage; Holographic film recording; Holographic television; Holographic X-ray microscope; Holographic supersonic camera; High frequency holography; Slant si...

S. Reichmann

1972-01-01

119

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

2008-10-07

120

Correlation of right and left ventricular ejection fraction and volume measurements  

SciTech Connect

First-pass radiocardiography and biplane angiocardiography were performed on 13 patients with left-sided regurgitant valvular disease (R+) and 7 patients without regurgitation but with coronary artery disease and/or cardiomyopathy (R-). Right and left ventricular volumes and ejection fractions were calculated and compared. In the R- group, corresponding right and left ventricular volumes and ejection fractions correlated highly with each other (r = 0.86-0.89, p approximately equal to 0.01). Ejection fractions in the R+ group correlated (r = 0.64, p less than 0.05) only because stroke volume correlation was very high (r = 0.93), with end-diastolic and end-systolic volumes showing no significant correlation. Right ventricular ejection fraction (RVEF) decreased significantly with increasing mean pulmonary artery pressure (PAP) in both R- and R+ groups. The correlation of RVEF and LVEF in the R- group appears to be multifactorial in origin, consisting of effects of increased PAP, the mechanical interference of an enlarged left ventricle on the right ventricle, and direct biventricular ischemic effects. In the R+ group, the correlation appears to be due to only increased PAP and its sequelae.

Benedetto, A.R.; Nusynowitz, M.L.

1988-06-01

121

Does Height to Width Ratio Correlate with Mean Volume in Gastropods?  

NASA Astrophysics Data System (ADS)

Marine organisms' shell shape and size show important biological information. For example, shape and size can dictate how the organism ranges for food and escapes predation. Due to lack of data and analysis, the evolution of shell size in marine gastropods (snails) remains poorly known. In this study, I attempt to find the relationship between height to width ratio and mean volume. I collected height and width measurements from primary literature sources and calculated volume from these measurements. My results indicate that there was no correlation between height to width ratio and mean volume between 500 to 200 Ma, but there was a correlation between 200 Ma to present where there is a steady increase in both height to width ratio and mean volume. This means that shell shape was not an important factor at the beginning of gastropod evolution but after 200 Ma body size evolution was increasingly driven by the height to width ratio.

Barriga, R.; Seixas, G.; Payne, J.

2012-12-01

122

Assessment of correlation between knee notch width index and the three-dimensional notch volume.  

PubMed

This study was done to determine whether there is a correlation between the notch volume and the notch width index (NWI) as measured on the three most frequently used radiographic views: the Holmblad 45 degrees, Holmblad 70 degrees, and Rosenberg view. The notch volume of 20 cadaveric knees was measured using Computed Tomography (CT). The Holmblad 45 degrees, Holmblad 70 degrees, and Rosenberg notch view radiographs were digitally re-created from the CT scans for each specimen, and the NWI was measured by two observers. The Pearson correlation coefficient between the NWI and notch volume was calculated, as well as between the three views. An independent t test was performed to determine the difference in NWI and notch volume between male and female specimens. The reliability for each view was also determined. There was no correlation between the NWI as measured on the Holmblad 45 degrees, Holmblad 70 degrees, or Rosenberg view and the notch volume. All three radiographic views proved reliable, but showed only a moderate correlation with each other. Men had larger notch volumes than women, but there was no difference in NWI. A knee with a small intercondylar notch is often considered an increased risk for ACL rupture. The NWI is a frequently used two-dimensional method to determine notch size. However, in the present study, this index was not positively correlated with the overall volume of the notch. Based on the results of the current study, the authors would advice to use caution when using notch view radiographs in a clinical setting to predict risk of ACL rupture. PMID:20376620

van Eck, Carola F; Martins, Cesar A Q; Lorenz, Stephan G F; Fu, Freddie H; Smolinski, P

2010-09-01

123

Correction for serial correlation in volume ratio models. Forest Service research paper  

SciTech Connect

Individual tree volume ratio models and associated taper functions are frequently used to estimate merchantable volume of trees to specific top diameters. However, little consideration has been given to the correlation between successive observations that exists in these models. An econometric procedure that corrects for this autocorrelation is presented. The corrected model is, in theory, closer to the 'true' model form and possesses confidence intervals that are more realistic than those given by uncorrected models.

Reams, G.A.

1994-03-01

124

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

125

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

126

Holographic interacting tachyon model  

NASA Astrophysics Data System (ADS)

We propose an interacting holographic tachyon model of dark energy. A correspondence between the tachyon energy density and the interacting holographic dark energy is established. As a result, we reconstruct the potential of the interacting holographic tachyon field and the dynamics of the tachyon field, in a flat Friedmann-Robertson-Walker background. We show that the evolution of the universe for -1 < w < 0 can be completely described by the resulting interacting tachyon model.

Rozas-Fernández, Alberto; Brizuela, David; Cruz, Norman

2010-05-01

127

Diffusion tensor imaging correlates with lesion volume in cerebral hemisphere infarctions  

PubMed Central

Background Both a large lesion volume and abnormalities in diffusion tensor imaging are independently associated with a poor prognosis after cerebral infarctions. Therefore, we assume that they are associated. This study assessed the associations between lesion volumes and diffusion tensor imaging in patients with a right-sided cerebral infarction. Methods The lesion volumes of 33 patients (age 65.9 ± 8.7, 26 males and 7 females) were imaged using computed tomography (CT) in the acute phase (within 3-4 hours) and magnetic resonance imaging (MRI) in the chronic phase (follow-up at 12 months, with a range of 8-27 months). The chronic-phase fractional anisotropy (FA) and mean diffusivity (MD) values were measured at the site of the infarct and selected white matter tracts. Neurological tests in both the acute and chronic phases, and DTI lateralization were assessed with the Wilcoxon signed-rank test. The effects of thrombolytic therapy (n = 10) were assessed with the Mann-Whitney U test. The correlations between the measured parameters were analysed with Spearman's rho correlation. Bonferroni post-hoc correction was used to compensate for the familywise error rate in multiple comparisons. Results Several MD values in the right hemisphere correlated positively and FA values negatively with the lesion volumes. These correlations included both lesion area and healthy tissue. The results of the mini-mental state examination and the National Institutes of Health Stroke Scale also correlated with the lesion volume. Conclusions A larger infarct volume is associated with more pronounced tissue modifications in the chronic stage as observed with the MD and FA alterations. PMID:20849612

2010-01-01

128

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

129

3D Digital Volume Correlation of Synchrotron Radiation Laminography images of ductile  

E-print Network

composition [2] and use of novel joining techniques such as friction stir welding [3] allows aluminium alloys concentration close to the notch tip. Aluminium alloy; Digital Volume Correlation; ductile fracture to reduce the weight of structures for transportation applications [1]. Recent progress in aluminium alloy

Paris-Sud XI, Université de

130

Three dimensional analysis of a tensile test on a propellant with digital volume correlation  

E-print Network

Three dimensional analysis of a tensile test on a propellant with digital volume correlation Fran;Abstract: A full three dimensional study of a tensile test on a sample made of polymer- bonded propellant, X-ray microtomography. 1 Introduction Propellant-like materials are a class of particulate

Paris-Sud XI, Université de

131

Sex, Ecology and the Brain: Evolutionary Correlates of Brain Structure Volumes in Tanganyikan Cichlids  

Microsoft Academic Search

Analyses of the macroevolutionary correlates of brain structure volumes allow pinpointing of selective pressures influencing specific structures. Here we use a multiple regression framework, including phylogenetic information, to analyze brain structure evolution in 43 Tanganyikan cichlid species. We analyzed the effect of ecological and sexually selected traits for species averages, the effect of ecological traits for each sex separately and

Alejandro Gonzalez-Voyer; Niclas Kolm

2010-01-01

132

Clinical Correlations of Diffusion and Perfusion Lesion Volumes in Acute Ischemic Stroke  

Microsoft Academic Search

The aim of this study was to describe the clinico-radiological correlations of magnetic resonance (MR) perfusion and diffusion-weighted imaging (DWI) abnormalities in ischemic stroke. Eighteen patients had undergone MR imaging and clinical evaluation within 24 h of symptom onset and at or after 7 days. During the first 24 h the volume of perfusion abnormality (measured on the relative mean

Alison E. Baird; Karl-Olof Lövblad; John F. Dashe; Ann Connor; Cara Burzynski; Gottfried Schlaug; Irina Straroselskaya; Robert R. Edelman; Steven Warach

2000-01-01

133

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

134

Incidence of radiation pneumonitis after thoracic irradiation: Dose-volume correlates  

SciTech Connect

Purpose: To define clinical and dosimetric parameters correlated with the risk of clinically relevant radiation pneumonitis (RP) after thoracic radiotherapy. Methods and Materials: Records of consecutive patients treated with definitive thoracic radiotherapy were retrospectively reviewed for the incidence of RP of Grade 2 or greater by the Common Toxicity Criteria. Dose-volume histograms using total lung volume (TL) and TL minus gross tumor volume (TL-G) were created with and without heterogeneity corrections. Mean lung dose (MLD), effective lung volume (V{sub eff}), and percentage of TL or TL-G receiving greater than or equal to 10, 13, 15, 20, and 30 Gy (V10-V30, respectively) were analyzed by logistic regression. Receiver operating characteristic (ROC) curves were generated to estimate RP predictive values. Results: Twelve cases of RP were identified in 92 eligible patients. Mean lung dose, V10, V13, V15, V20, and V{sub eff} were significantly correlated to RP. Combinations of MLD, V{sub eff}, V20, and V30 lost significance using TL-G and heterogeneity corrections. Receiver operating characteristic analysis determined V10 and V13 as the best predictors of RP risk, with a decrease in predictive value above those volumes. Conclusions: Intrathoracic radiotherapy should be planned with caution when using radiotherapy techniques delivering doses of 10 to 15 Gy to large lung volumes.

Schallenkamp, John M. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Miller, Robert C. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Brinkmann, Debra H. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Foote, Tyler [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Garces, Yolanda I. [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States)

2007-02-01

135

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

136

Holographic movie: the first step to holographic video  

Microsoft Academic Search

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

Kazuhito Higuchi; Jun Ishikawa; Shigeo Hiyama

1992-01-01

137

Modified Pediatric ASPECTS Correlates with Infarct Volume in Childhood Arterial Ischemic Stroke  

PubMed Central

Background and Purpose: Larger infarct volume as a percent of supratentorial brain volume (SBV) predicts poor outcome and hemorrhagic transformation in childhood arterial ischemic stroke (AIS). In perinatal AIS, higher scores on a modified pediatric version of the Alberta Stroke Program Early CT Score using acute MRI (modASPECTS) predict later seizure occurrence. The objectives were to establish the relationship of modASPECTS to infarct volume in perinatal and childhood AIS and to establish the interrater reliability of the score. Methods: We performed a cross sectional study of 31 neonates and 40 children identified from a tertiary care center stroke registry with supratentorial AIS and acute MRI with diffusion weighted imaging (DWI) and T2 axial sequences. Infarct volume was expressed as a percent of SBV using computer-assisted manual segmentation tracings. ModASPECTS was performed on DWI by three independent raters. The modASPECTS were compared among raters and to infarct volume as a percent of SBV. Results: ModASPECTS correlated well with infarct volume. Spearman rank correlation coefficients (?) for the perinatal and childhood groups were 0.76, p?correlation coefficients for the three raters for the neonates and children were 0.93 [95% confidence interval (CI) 0.89–0.97, p?volume as a percent of SBV with a high degree of validity and interrater reliability. PMID:23015799

Beslow, Lauren A.; Vossough, Arastoo; Dahmoush, Hisham M.; Kessler, Sudha Kilaru; Stainman, Rebecca; Favilla, Christopher G.; Wusthoff, Courtney J.; Zelonis, Sarah; Licht, Daniel J.; Ichord, Rebecca N.; Smith, Sabrina E.

2012-01-01

138

Athermal holographic filters  

Microsoft Academic Search

This letter presents the theory and experimental results of an athermal holographic filter design employing a thermally actuated microelectromechanical system mirror to compensate for the drift of Bragg wavelength due to changes of temperature. The center wavelength of our holographic filter is shown to remain constant from 21°C to 60°C.

Hung-Te Hsieh; G. Panotopoulos; M. Liger; Yu-Chong Tai; D. Psaltis

2004-01-01

139

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

140

The correlation between Emotional Intelligence and gray matter volume in university students.  

PubMed

A number of recent studies have investigated the neurological substrates of Emotional Intelligence (EI), but none of them have considered the neural correlates of EI that are measured using the Schutte Self-Report Emotional Intelligence Scale (SSREIS). This scale was developed based on the EI model of Salovey and Mayer (1990). In the present study, SSREIS was adopted to estimate EI. Meanwhile, magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) were used to evaluate the gray matter volume (GMV) of 328 university students. Results found positive correlations between Monitor of Emotions and VBM measurements in the insula and orbitofrontal cortex. In addition, Utilization of Emotions was positively correlated with the GMV in the parahippocampal gyrus, but was negatively correlated with the VBM measurements in the fusiform gyrus and middle temporal gyrus. Furthermore, Social Ability had volume correlates in the vermis. These findings indicate that the neural correlates of the EI model, which primarily focuses on the abilities of individuals to appraise and express emotions, can also regulate and utilize emotions to solve problems. PMID:25282329

Tan, Yafei; Zhang, Qinglin; Li, Wenfu; Wei, Dongtao; Qiao, Lei; Qiu, Jiang; Hitchman, Glenn; Liu, Yijun

2014-11-01

141

High speed optical object recognition processor with massive holographic memory  

NASA Technical Reports Server (NTRS)

Real-time object recognition using a compact grayscale optical correlator will be introduced. A holographic memory module for storing a large bank of optimum correlation filters, to accommodate the large data throughput rate needed for many real-world applications, has also been developed. System architecture of the optical processor and the holographic memory will be presented. Application examples of this object recognition technology will also be demonstrated.

Chao, T.; Zhou, H.; Reyes, G.

2002-01-01

142

Endothelial progenitor cells correlate with lesion volume and growth in acute stroke  

PubMed Central

Objectives: Circulating endothelial progenitor cells (EPC) are markers of vascular injury and their numbers decrease in acute stroke. However, the relation of EPC levels to stroke severity has not been quantified. MRI measurements of lesion volume provide an objective method for stroke severity assessment and outcome prediction. This cross-sectional study aims to determine whether EPC are correlated with lesion volume at baseline, lesion growth, and final lesion volume. Methods: Seventeen patients (median age 63 years, NIH Stroke Scale score 7) were selected from 175 patients with imaging-confirmed acute ischemic stroke. EPC were quantified by flow cytometry using CD34, CD133, and VEGFR2 surface markers. Brain MRI was performed at baseline and at days 1 and 5 after the stroke onset. Stroke lesion volumes were quantified. Results: Larger lesion volumes measured on diffusion-weighted images (DWI) at baseline were associated with low EPC levels, while smaller lesion volumes and less lesion growth were linked with high levels of EPC subsets (CD34+CD133+, CD133+VEGFR2+, and CD34+ CD133+VEGFR2+). Similar results were observed with DWI lesion volumes and EPC (CD34+CD133+) on day 1. Lesion growth volume, represented as a difference between final lesion volume and baseline DWI, was larger in patients with lower day 1 EPC (CD133+VEGFR2+). After adjustments for age and admission glucose (model 1), mean arterial pressure and white blood cells (model 2), INR and hematocrit (model 3), the CD34+CD133+ subset remained predictive of baseline and day 1 lesion volumes, while CD133+VEGFR2+ predicted baseline lesion volume and growth of lesion volume. Conclusions: Higher EPC levels were indicative of smaller volumes of acute lesion, final lesion, and lesion growth, and may serve as markers of acute phase stroke severity. However, a larger prospective study is needed to confirm our findings. GLOSSARY DBP = diastolic blood pressure; DWI = diffusion-weighted images; EPC = endothelial progenitor cells; FLAIR = fluid-attenuated inversion recovery; Hb = hemoglobin; INR = international normalized ratio; LSN = last seen normal; NIHSS = NIH Stroke Scale score; WBC = white blood cells; WHC = Washington Hospital Center. PMID:21135380

Bogoslovsky, T.; Chaudhry, A.; Latour, L.; Maric, D.; Luby, M.; Spatz, M.; Frank, J.; Warach, S.

2010-01-01

143

Possible Origin of Gravity and the Holographic Principle  

E-print Network

Assuming the holographic principle, the gravitational force can be formulated thermodynamically as an entropic force, but the mechanism by which the attraction between two masses occurs is not clear. The physical basis for the holographic principle is also unknown. My primary assumption is that empty space consists of discrete countable units that have on the order of one bit of entropy per cubic Planck unit. The basic idea here is simply that rather than matter just occupying empty space, the presence of matter excludes discrete units of space that have entropy. I argue that this volume exclusion of empty space leads to an attractive gravitational force and to the holographic principle.

Arnold Stein

2010-10-12

144

Holographic dual of free field theory  

SciTech Connect

We derive a holographic dual description of free quantum field theory in arbitrary dimensions, by reinterpreting the exact renormalization group to obtain a higher spin gravity theory of the general type which had been proposed and studied as a dual theory. We show that the dual theory reproduces all correlation functions.

Douglas, Michael R.; Mazzucato, Luca; Razamat, Shlomo S. [Simons Center for Geometry and Physics and YITP, Stony Brook University, Stony Brook, New York 11794 (United States)

2011-04-01

145

Fiber infrared holographic interferometer for nondestructive testing  

Microsoft Academic Search

In this paper, the optical set-up and construction of the portable hand held holographic camera is described. The high output power (150 mW) semiconductor pig tailed laser diode as light source was used. The wavelength of the emitted radiation is 980 nm. Optical fiber elements have been used. The interferometry correlation methods was used for testing the possibility to measure

V. A. Babenko; V. B. Konstantinov; A. F. Maliy

2003-01-01

146

Individual differences in posterior cortical volume correlate with proneness to pride and gratitude.  

PubMed

Proneness to specific moral sentiments (e.g. pride, gratitude, guilt, indignation) has been linked with individual variations in functional MRI (fMRI) response within anterior brain regions whose lesion leads to inappropriate behaviour. However, the role of structural anatomical differences in rendering individuals prone to particular moral sentiments relative to others is unknown. Here, we investigated grey matter volumes (VBM8) and proneness to specific moral sentiments on a well-controlled experimental task in healthy individuals. Individuals with smaller cuneus, and precuneus volumes were more pride-prone, whereas those with larger right inferior temporal volumes experienced gratitude more readily. Although the primary analysis detected no associations with guilt- or indignation-proneness, subgenual cingulate fMRI responses to guilt were negatively correlated with grey matter volumes in the left superior temporal sulcus and anterior dorsolateral prefrontal cortices (right >left). This shows that individual variations in functional activations within critical areas for moral sentiments were not due to grey matter volume differences in the same areas. Grey matter volume differences between healthy individuals may nevertheless play an important role by affecting posterior cortical brain systems that are non-critical but supportive for the experience of specific moral sentiments. This may be of particular relevance when their experience depends on visuo-spatial elaboration. PMID:24106333

Zahn, Roland; Garrido, Griselda; Moll, Jorge; Grafman, Jordan

2014-11-01

147

Philippine Trading volume and serial correlation in stock returns in an emerging market : a case study of Pakistan  

Microsoft Academic Search

This paper examines the relationship between aggregate stock market trading volume and serial correlation of daily stock returns from December 1991 to April 2006. The empirical results reveal that there is a first-order positive autocorrelation between future and present returns. The serial correlation becomes negative when present returns are weighted by a change in the trading volume. This indicates that

Mohammed Nishat; Khalid Mustafa

2008-01-01

148

Experimental approach toward holographic interferometric fringe interpretation  

NASA Technical Reports Server (NTRS)

Current literature concerning the measurement of small displacements by the laser holographic technique was reviewed. It was found that existing theories are extremely difficult, if not impossible, to apply to any realistic nondestructive testing conditions in which the geometries of the objects are complex and the three-dimensional displacements are irregular. An experimental approach was adopted for interpreting correlation between real time holographic fringe patterns and small displacements. Preliminary results show that the present method is feasible for the quantitative interpretation of the fringes as well as the calibration of the mobile HNDT system.

Liu, H. K.

1974-01-01

149

Temporal variations of serial correlations of trading volume in the US stock market  

NASA Astrophysics Data System (ADS)

Serial correlations in the trading volume of the US stock market are investigated in this paper. The use of the detrended fluctuation analysis implemented within a rolling window indicated that, for the period 1929-2011, the strength of correlations exhibits important temporal variations with a trend shift by the 1990s, and 4-year and 21-year cycles. These empirical findings are compared to those obtained for mature international stock markets (FTSE-100 and Nikkei) and discussed in terms of potential economic and financial implications.

Alvarez-Ramírez, José; Rodríguez, Eduardo

2012-08-01

150

Two-photon excitation fluorescence correlation spectroscopy of diffusion for Gaussian-Lorentzian volumes.  

PubMed

Fluorescence correlation spectroscopy (FCS) is valuable in many scientific domains where diffusion plays a fundamental role. One important experimental realization is based on fluorescence induced by two-photon excitation (TPE). In comparison with one-photon excitation (OPE), TPE-FCS defines better the interrogation volume and the background noise is sensibly reduced. Within this context and for overfilled objective lenses, the three-dimensional Gaussian (3DG) approximation, according to which the spectroscopic interaction is spatially defined by Gaussian profiles only, guarantees a simple analytical data interpretation. By contrast, the volume illuminated by the laser beam focused with partially filled objective lenses follows a Gaussian-Lorentzian (GL) distribution that is taken into account by means of numerical methods only. Here we show that contrary to common belief, the assumption of a GL volume does not hamper analytical treatment of TPE-FCS. Differences and similarities in comparison with the 3DG approximation are discussed. PMID:18380493

Marrocco, Michele

2008-05-01

151

Correlation between gray\\/white matter volume and cognition in healthy elderly people  

Microsoft Academic Search

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 community-dwelling healthy elderly individuals. We used the Information and Digit

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

2011-01-01

152

Correlations among Brain Gray Matter Volumes, Age, Gender, and Hemisphere in Healthy Individuals  

Microsoft Academic Search

To determine the relationship between age and gray matter structure and how interactions between gender and hemisphere impact this relationship, we examined correlations between global or regional gray matter volume and age, including interactions of gender and hemisphere, using a general linear model with voxel-based and region-of-interest analyses. Brain magnetic resonance images were collected from 1460 healthy individuals aged 20–69

Yasuyuki Taki; Benjamin Thyreau; Shigeo Kinomura; Kazunori Sato; Ryoi Goto; Ryuta Kawashima; Hiroshi Fukuda

2011-01-01

153

Holographic color schlieren.  

PubMed

A 20-in (51-cm) diam schlieren system was convereted to a genrualized holographic flow visualization system. The system has been used successfully in producing the following types of visualization from a single holographic plate: three-dimensional photography, variable focus shadowgraph, variable knife-edge position schlieren, color-schlieren, and interferometry. All of these except for holographic color schlieren have previously been reported with varying degrees of success. This paper presents a technique for producing color schlierent photographs from holograms formed in the above system and shows preliminary results of the application. The method possesses a number of advantages over conventional color schlieren photography. PMID:20072572

O'Hare, J E; Trolinger, J D

1969-10-01

154

Digital holographic microscopy for the evaluation of human sperm structure.  

PubMed

Summary 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

155

Interactive Holographic Cinema  

E-print Network

computer program performs stereoscopic reconstruction in real-time during presentation. Artists and computer users could then use a hardware device, such as the Microsoft Kinect, to explore the holographic cinematic form interactively....

Portales, Christopher

2012-07-16

156

Geochemical correlation of three large-volume ignimbrites from the Yellowstone hotspot track, Idaho, USA  

NASA Astrophysics Data System (ADS)

Three voluminous rhyolitic ignimbrites have been identified along the southern margin of the central Snake River Plain. As a result of wide-scale correlations, new volume estimates can be made for these deposits: ~350 km3 for the Steer Basin Tuff and Cougar Point Tuff XI, and ~1,000 km3 for Cougar Point Tuff XIII. These volumes exclude any associated regional ashfalls and correlation across to the north side of the plain, which has yet to be attempted. Each correlation was achieved using a combination of methods including field logging, whole rock and mineral chemistry, magnetic polarity, oxygen isotope signature and high-precision 40Ar/39Ar geochronology. The Steer Basin Tuff, Cougar Point Tuff XI and Cougar Point Tuff XIII have deposit characteristics typical of `Snake River (SR)-type' volcanism: they are very dense, intensely welded and rheomorphic, unusually well sorted with scarce pumice and lithic lapilli. These features differ significantly from those of deposits from the better-known younger eruptions of Yellowstone. The ignimbrites also exhibit marked depletion in ?18O, which is known to characterise the SR-type rhyolites of the central Snake River Plain, and cumulatively represent ~1,700 km3 of low ?18O rhyolitic magma (feldspar values 2.3-2.9‰) erupted within 800,000 years. Our work reduces the total number of ignimbrites recognised in the central Snake River Plain by 6, improves the link with the ashfall record of Yellowstone hotspot volcanism and suggests that more large-volume ignimbrites await discovery through detailed correlation work amidst the vast ignimbrite record of volcanism in this bimodal large igneous province.

Ellis, Ben S.; Branney, M. J.; Barry, T. L.; Barfod, D.; Bindeman, I.; Wolff, J. A.; Bonnichsen, B.

2012-01-01

157

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

158

Characterization of a real-time high-sensitivity photopolymer for holographic display and holographic interferometry  

NASA Astrophysics Data System (ADS)

In this paper, a red-sensitive photopolymer based on multiple polymerizable monomers is developed for holographic applications. The detailed quantitative experiments on the reagent concentrations, the exposure, the thickness of the photosensitive layer, are conducted to determine an optimum recipe, and bright volume phase holograms with high diffraction efficiency are obtained in our experiments at the exposure level of 4mJ/cm2. This photopolymer also has higher resolution and self-development capacity. This makes it very convenient and useful for the applications of both real-time and double exposure holographic interferometry, some preliminary experiments of holographic interferometry are demonstrated in this paper for the nondestructive testing and measurement of minor distortion and displacement.

Guo, Xiaowei; Zhu, Jianhua; Xia, Chuanqin; Li, Jianfeng; Chen, Li

2005-02-01

159

Stochastic rank correlation for slice-to-volume registration of fluoroCT/CT imaging  

NASA Astrophysics Data System (ADS)

Slice-to-Volume registration is a special case of 2D/3D registration where a single slice obtained using a stationary scanner geometry is registered to a pre-interventional diagnostic volume scan. Examples include interventional magnetic resonance imaging (IMRI) or fluoroscopic computed tomography (CT). In a recent study in FluoroCT/ CT registration, we have shown that conventional cross correlation (CC), together with repeated use of conventional local optimization algorithms, provides an optimum measure for slice-to-volume registration for monoenergetic CT imaging data. If the required linear relationship between corresponding pixel pairs is offended (e. g. by using X-rays of different energy or by varying detector characteristics), CC becomes an unreliable measure of image similarity. A more general merit function like normalized mutual information (NMI) serves better in such a case but is stricken with local minima caused by sparse population of joint histograms. We present a novel merit function for 2D/3D registration named stochastic rank correlation (SRC), which is well-suited for intramodal dual-energy imaging. A first evaluation of SRC is given on a set of simulated and clinical FluoroCT/CT scan image data sets.

Birkfellner, Wolfgang; Figl, Michael; Bergmann, Helmar

2007-03-01

160

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

161

Lower Hemoglobin Correlates with Larger Stroke Volumes in Acute Ischemic Stroke  

PubMed Central

Background Hemoglobin tetramers are the major oxygen-carrying molecules within the blood. We hypothesized that a lower hemoglobin level and its reduced oxygen-carrying capacity would associate with larger infarction in acute ischemic stroke patients. Methods We studied 135 consecutive patients with acute ischemic stroke and perfusion brain MRI. We explored the association of admission hemoglobin with initial infarct volumes on acute images and the volume of infarct expansion on follow-up images. Multivariable linear regression was performed to analyze the independent effect of hemoglobin on imaging outcomes. Results Bivariate analyses showed a significant inverse correlation between hemoglobin and initial volume in diffusion-weighted imaging (r = ?0.20, p = 0.02) and absolute infarct growth (r = ?0.20, p = 0.02). Multivariable linear regression modeling revealed that hemoglobin remained independently predictive of larger infarct volumes acutely (p < 0.005) and with greater infarct expansion (p < 0.01) after adjusting for known covariates. Conclusions Hemoglobin level at the time of acute ischemic stroke associates with larger infarcts and increased infarct growth. Clarification of the mechanism of this effect may yield novel insights for therapy. PMID:22566982

Kimberly, W. Taylor; Wu, Ona; Arsava, E. Murat; Garg, Priya; Ji, Ruijun; Vangel, Mark; Singhal, Aneesh B.; Ay, Hakan; Sorensen, A. Gregory

2011-01-01

162

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

163

Confined detection volume of fluorescence correlation spectroscopy by bare fiber probes.  

PubMed

A fiber-tip-based near-field fluorescence correlation spectroscopy (FCS) has been developed for confining the detection volume to sub-diffraction-limited dimensions. This near-field FCS is based on near-field illumination by coupling a scanning near-field optical microscope (SNOM) to a conventional confocal FCS. Single-molecule FCS analysis at 100 nM Rhodamine 6G has been achieved by using bare chemically etched, tapered fiber tips. The detection volume under control of the SNOM system has been reduced over one order of magnitude compared to that of the conventional confocal FCS. Related factors influencing the near-field FCS performance are investigated and discussed in detail. In this proof-of-principle study, the preliminary experimental results suggest that the fiber-tip-based near-field FCS might be a good alternative to realize localized analysis at the single-molecule level. PMID:19575194

Lu, Guowei; Lei, Franck H; Angiboust, Jean-François; Manfait, Michel

2010-04-01

164

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

165

Digital data storage in a phase-encoded holographic memory system: data quality and security  

Microsoft Academic Search

ABSTRACT We review the crucial properties of a phase-encoded volume holographic storage system in terms of data quality and security, which are the key issues of any bulk memory system. Two major problems which need to be tackled in holographic storage systems in terms of data quality are the hologram erasure during readout and the data encoding schemes for error-free

G. Berger; K.-O. Muller; C. Denz; I. Foldvari; A. Peter

166

Enhancement of the resolving power of holographic selectors of laser radiation based on dichromated gelatin  

Microsoft Academic Search

It is shown that the resolving power of dichromated gelatin (DG) volume phase gratings is limited most significantly by changes in layer parameters occurring under processing during development. The recording characteristics of holographic grazing-incidence gratings are examined, and factors leading to the appearance of optical defects in DG holographic gratings are investigated. Inhomogeneous transverse deformations of the layer are shown

B. Iu. Bazhenov; N. M. Burykin; M. V. Vasnetsov; M. S. Soskin; V. B. Taranenko

1983-01-01

167

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

168

Local fluctuations and spatial correlations in granular flows under constant-volume quasistatic shear.  

PubMed

We investigate the local fluctuations in dense granular media subjected to athermal, quasistatic shearing, based on three-dimensional discrete element method simulations. By shearing granular assemblies of different polydispersities under constant-volume constraint, we quantify the characteristics of local structures (in terms of local volume and local anisotropy) and local deformation (using local shear strain and nonaffine displacement). The distribution of the local volume in a granular medium is found unchanged during the entire shearing process, which indicates a constant temperaturelike compactivity for the material. The compactivity is not, however, equilibrated among different particle groups in a polydisperse assembly. The local structures of a disordered granular assembly are inherently anisotropic. The fluctuations in local anisotropy can be well captured by a gamma or mixed-gamma distribution function, which is also unchanged during the shear. The local anisotropic orientation evolves towards the coaxial direction of the stress anisotropy with shear. The deformation characteristics of a jammed granular medium have their origins in the structural amorphousness. The local shear strain field depicts clear shear transformation zones which act as plasticity carriers. The spatial correlation of the local shear strains exhibits a fourfold pattern which is stronger in the stress deviatoric planes than in the stress isotropic plane. The fluctuations of nonaffine displacement suggest an isotropic granular temperature and an isotropic spatial correlation independent of the stress state. Both the local strain and the nonaffine displacement exhibit a power-law decayed distribution with a long-range correlation. We further modify the shear-transformation-zone theory to predict the pressure-dependent constitutive behavior of a sheared granular material and compare its prediction with our simulation data. PMID:24827242

Guo, Ning; Zhao, Jidong

2014-04-01

169

Fluctuations and correlations of conserved charges in an excluded-volume hadron resonance gas model  

NASA Astrophysics Data System (ADS)

We present temperature and baryonic chemical potential dependence of higher-order fluctuations and the correlation between conserved charges in an excluded-volume hadron resonance gas model. Products of moments, such as the ratio of variance to mean, product of skewness and standard deviation, product of kurtosis and variance, for the net proton, net kaon, and net charge have been evaluated on the phenomenologically determined freeze-out curve. Further, products of moments for net proton and net charge have been compared with the experimental data measured by the STAR experiment. The dependence of the model result on the hadronic radius parameter has also been discussed.

Bhattacharyya, Abhijit; Das, Supriya; Ghosh, Sanjay K.; Ray, Rajarshi; Samanta, Subhasis

2014-09-01

170

Correlation between intra-abdominal pressure and pulmonary volumes after superior and inferior abdominal surgery  

PubMed Central

OBJECTIVE: Patients undergoing abdominal surgery are at risk for pulmonary complications. The principal cause of postoperative pulmonary complications is a significant reduction in pulmonary volumes (FEV1 and FVC) to approximately 65-70% of the predicted value. Another frequent occurrence after abdominal surgery is increased intra-abdominal pressure. The aim of this study was to correlate changes in pulmonary volumes with the values of intra-abdominal pressure after abdominal surgery, according to the surgical incision in the abdomen (superior or inferior). METHODS: We prospectively evaluated 60 patients who underwent elective open abdominal surgery with a surgical time greater than 240 minutes. Patients were evaluated before surgery and on the 3rd postoperative day. Spirometry was assessed by maximal respiratory maneuvers and flow-volume curves. Intra-abdominal pressure was measured in the postoperative period using the bladder technique. RESULTS: The mean age of the patients was 56±13 years, and 41.6% 25 were female; 50 patients (83.3%) had malignant disease. The patients were divided into two groups according to the surgical incision (superior or inferior). The lung volumes in the preoperative period showed no abnormalities. After surgery, there was a significant reduction in both FEV1 (1.6±0.6 L) and FVC (2.0±0.7 L) with maintenance of FEV1/FVC of 0.8±0.2 in both groups. The maximum intra-abdominal pressure values were similar (p?=?0.59) for the two groups. There was no association between pulmonary volumes and intra-abdominal pressure measured in any of the groups analyzed. CONCLUSIONS: Our results show that superior and inferior abdominal surgery determines hypoventilation, unrelated to increased intra-abdominal pressure. Patients at high risk of pulmonary complications should receive respiratory care even if undergoing inferior abdominal surgery. PMID:25029580

de Cleva, Roberto; de Assumpcao, Marianna Siqueira; Sasaya, Flavia; Chaves, Natalia Zuniaga; Santo, Marco Aurelio; Flo, Claudia; Lunardi, Adriana C.; Filho, Wilson Jacob

2014-01-01

171

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

172

Bifocal-polarization holographic lens  

Microsoft Academic Search

We present a holographic lens with novel features recorded in an azopolymer film. Two holographic modulations, bulk birefringence and surface relief, are induced in the medium at the same time. The resultant holographic element has two focal planes, and the polarization of light in the focal points depends on the polarization of the incident light. Applications of this device for

Geminiano Martinez-Ponce; Tsveta Petrova; Natalia Tomova; Violeta Dragostinova; Todor Todorov; Ludmila Nikolova

2004-01-01

173

Introductory notes on holographic superconductors  

E-print Network

The purpose of these lecture notes is to give a quick and introductory overview of holographic superconductors. Besides the actual description of the standard holographic superconductor, attention is paid to the motivations and the relation with the previous, non-holographic context.

Musso, Daniele

2014-01-01

174

Introductory notes on holographic superconductors  

E-print Network

The purpose of these lecture notes is to give a quick and introductory overview of holographic superconductors. Besides the actual description of the standard holographic superconductor, attention is paid to the motivations and the relation with the previous, non-holographic context.

Daniele Musso

2014-01-07

175

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; Hammarsjo, Anna; Bystrom, Birgitta; L Lalitkumar, Parameswaran Grace; Gemzell-Danielsson, Kristina

2013-01-01

176

Causal holographic information  

NASA Astrophysics Data System (ADS)

We propose a measure of holographic information based on a causal wedge construction. The motivation behind this comes from an attempt to understand how boundary field theories can holographically reconstruct spacetime. We argue that given the knowledge of the reduced density matrix in a spatial region of the boundary, one should be able to reconstruct at least the corresponding bulk causal wedge. In attempt to quantify the `amount of information' contained in a given spatial region in field theory, we consider a particular bulk surface (specifically a co-dimension two surface in the bulk spacetime which is an extremal surface on the boundary of the bulk causal wedge), and propose that the area of this surface, measured in Planck units, naturally quantifies the information content. We therefore call this area the causal holographic information. We also contrast our ideas with earlier studies of holographic entanglement entropy. In particular, we establish that the causal holographic information, whilst not being a von Neumann entropy, curiously enough agrees with the entanglement entropy in all cases where one has a microscopic understanding of entanglement entropy.

Hubeny, Veronika E.; Rangamani, Mukund

2012-06-01

177

Correlation of volume, position of stone, and hydronephrosis with microhematuria in patients with solitary urolithiasis  

PubMed Central

Background The aim of this study was to determine the relationship between hematuria and volume, position of stone, and hydronephrosis in patients with a solitary stone, using unenhanced multidetector computed tomography (MDCT). Material/Methods This retrospective study evaluated the clinical and radiological records of 83 patients undergoing MDCT for the evaluation of acute flank pain and suspected renal colic, who also underwent a microscopic urinalysis at the emergency department of our hospital during a 1-year period. Inclusion criteria of the MDCT study were solitary urolithiasis and cumulative stone diameter under 1 cm. Results A total of 83 patients were included in the study, with a mean age of 42.1±14.4 years; 48 (57.8%) were females and 35 (42.2%) were males. Detection of 5 or more red cells on urinalysis was regarded as microscopic hematuria, and was positive in 46 patients (55.4%). There was a positive correlation between the position of the stone (especially upper two-thirds ureteral stones) and microhematuria rate (r: 0.28, p=0.009). There was a statistically significant difference in presence of hydronephrosis between the microhematuria (36 patients, 78%) and non-microhematuria (12 patients, 32%) groups (p<0.001). The median stone volume between the microhematuria and non-microhematuria groups were not statistically different, 37.5 mm3 (range 5–425) and 28 mm3 (range 4–412), respectively (p=0.39). Conclusions Although stone volume is one of the best indicators of stone burden, it was not correlated with microhematuria. However, in patients with renal colic, microhematuria requires ultrasound examination whether hydronephrosis and ureteral stones are present or not. Further studies with larger sample sizes are warranted. PMID:23612123

Inci, Mehmet Fatih; Ozkan, Fuat; Bozkurt, Selim; Sucakli, Mustafa Haki; Altunoluk, Bulent; Okumus, Mehmet

2013-01-01

178

Full-color holographic 3D printer  

NASA Astrophysics Data System (ADS)

A holographic 3D printer is a system that produces a direct hologram with full-parallax information using the 3-dimensional data of a subject from a computer. In this paper, we present a proposal for the reproduction of full-color images with the holographic 3D printer. In order to realize the 3-dimensional color image, we selected the 3 laser wavelength colors of red (?=633nm), green (?=533nm), and blue (?=442nm), and we built a one-step optical system using a projection system and a liquid crystal display. The 3-dimensional color image is obtained by synthesizing in a 2D array the multiple exposure with these 3 wavelengths made on each 250mm elementary hologram, and moving recording medium on a x-y stage. For the natural color reproduction in the holographic 3D printer, we take the approach of the digital processing technique based on the color management technology. The matching between the input and output colors is performed by investigating first, the relation between the gray level transmittance of the LCD and the diffraction efficiency of the hologram and second, by measuring the color displayed by the hologram to establish a correlation. In our first experimental results a non-linear functional relation for single and multiple exposure of the three components were found. These results are the first step in the realization of a natural color 3D image produced by the holographic color 3D printer.

Takano, Masami; Shigeta, Hiroaki; Nishihara, Takashi; Yamaguchi, Masahiro; Takahashi, Susumu; Ohyama, Nagaaki; Kobayashi, Akihiko; Iwata, Fujio

2003-05-01

179

Correlation between Serum D-Dimer Level and Volume in Acute Ischemic Stroke  

PubMed Central

Objective D-dimer is a breakdown product of fibrin mesh after factor XIII stabilization. Previously, many authors have demonstrated a relationship between D-dimer level and stroke progression or type. This study aimed to investigate the relationship between D-dimer level and stroke volume. Methods Between January 2008 and December 2009, we analyzed the D-dimer levels of 59 acute ischemic stroke patients in our neurosurgical department both upon admission and after seven days of initial treatment. Each patient's National Institute of Health Stroke Scale score, modified Rankin Scales score, Glasgow outcome score, and infarction volume were also evaluated. Results Mean D-dimer level at admission was 626.6 µg/L (range, 77-4,752 µg/L) and the mean level measured after seven days of treatment was 238.3 µg/L (range, 50-924 µg/L). Mean D-dimer level at admission was 215.3 µg/L in patients with focal infarctions, 385.7 µg/L in patients with multiple embolic infarctions, 566.2 µg/L in those with 1-19 cc infarctions, 668.8 µg/L in 20-49 cc infarctions, 702.5 µg/L in 50-199 cc infarctions, and 844.0 µg/L in >200 cc infarctions (p=0.044). On the 7th day of treatment, the D-dimer levels had fallen to 201.0 µg/L, 293.2 µg/L, 272.0 µg/L, 232.8 µg/L, 336.6 µg/L, and 180.0 µg/L, respectively (p=0.530). Conclusion Our study shows that D-dimer level has the positive correlation with infarction volume and can be use to predict infarction-volume. PMID:22053225

Park, Young-Woo; Choi, Ha-Young

2011-01-01

180

Periodically driven holographic superconductor  

NASA Astrophysics Data System (ADS)

As a first step towards our holographic investigation of the far-from-equilibrium physics of periodically driven systems at strong coupling, we explore the real time dynamics of holographic superconductor driven by a monochromatically alternating electric field with various frequencies. As a result, our holographic superconductor is driven to the final oscillating state, where the condensate is suppressed and the oscillation frequency is controlled by twice of the driving frequency. In particular, in the large frequency limit, the three distinct channels towards the final steady state are found, namely under damped to superconducting phase, over damped to superconducting and normal phase, which can be captured essentially by the low lying spectrum of quasi-normal modes in the time averaged approximation, reminiscent of the effective field theory perspective.

Li, Wei-Jia; Tian, Yu; Zhang, Hongbao

2013-07-01

181

Holographic inflation and the conservation of ?  

NASA Astrophysics Data System (ADS)

In a holographic description of inflation, cosmological time evolution in the bulk is expected to correspond to the renomalization group (RG) flow in a dual boundary theory. Here, we analyze this expectation by computing the correlation functions of the curvature perturbation ? holographically. For this purpose, we use a deformed conformal field theory at the boundary, with a single deformation operator. In standard single field models of inflation, ? is known to be conserved at large scales under very general conditions. However, we find that this is not generically the case in the dual description. The requirement that higher correlators of ? should be conserved severely restricts the possibilities for the RG flow. With such restriction, the power spectrum P ? must follow an exact power law, at least within the regime of validity of conformal perturbation theory.

Garriga, Jaume; Urakawa, Yuko

2014-06-01

182

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

183

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

184

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

185

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

186

Deriving particle distributions from in-line Fraunhofer holographic data  

NASA Astrophysics Data System (ADS)

Holographic data are acquired during hydrodynamic experiments at the Pegasus Pulsed Power Facility at the Los Alamos National Laboratory. These experiments produce a fine spray of fast-moving particles. Snapshots of the spray are captured using in-line Fraunhofer holographic techniques. Roughly one cubic centimeter is recorded by the hologram. Minimum detectable particle size in the data extends down to 2 microns. In a holography reconstruction system, a laser illuminates the hologram as it rests in a three- axis actuator, recreating the snapshot of the experiment. A computer guides the actuators through an orderly sequence programmed by the user. At selected intervals, slices of this volume are captured and digitized with a CCD camera. Intermittent on-line processing of the image data and computer control of the camera functions optimizes statistics of the acquired image data for off-line processing. Tens of thousands of individual data frames (30 to 40 gigabytes of data) are required to recreate a digital representation of the snapshot. Throughput of the reduction system is 550 megabytes per hour (MB/hr). Objects and associated features from the data are subsequently extracted during off-line processing. Discrimination and correlation tests reject noise, eliminate multiple-counting of particles, and build an error model to estimate performance. Objects surviving these tests are classified as particles. The particle distributions are derived from the data base formed by these particles, their locations and features. Throughput of the off-line processing exceeds 500 MB/hr. This paper describes the reduction system, outlines the off-line processing procedure, summarizes the discrimination and correlation tests, and reports numerical results for a sample data set.

Tunnell, Thomas W.; Malone, Robert M.; Frederickson, Rosmarie H.; DeLanoy, Albert D.; Johnson, Douglas E.; Ciarcia, Christopher A.; Sorenson, Danny S.

1997-10-01

187

Deriving particle distributions from in-line Fraunhofer holographic data  

SciTech Connect

Holographic data are acquired during hydrodynamic experiments at the Pegasus Pulsed Power Facility at the Los Alamos National Laboratory. These experiments produce a fine spray of fast-moving particles. Snapshots of the spray are captured using in-line Fraunhofer holographic techniques. Roughly one cubic centimeter is recorded by the hologram. Minimum detectable particle size in the data extends down to 2 microns. In a holography reconstruction system, a laser illuminates the hologram as it rests in a three axis actuator, recreating the snapshot of the experiment. A computer guides the actuators through an orderly sequence programmed by the user. At selected intervals, slices of this volume are captured and digitized with a CCD camera. Intermittent on-line processing of the image data and computer control of the camera functions optimizes statistics of the acquired image data for off-line processing. Tens of thousands of individual data frames (30 to 40 gigabytes of data) are required to recreate a digital representation of the snapshot. Throughput of the reduction system is 550 megabytes per hour (MB/hr). Objects and associated features from the data are subsequently extracted during off-line processing. Discrimination and correlation tests reject noise, eliminate multiple particles, and build an error model to estimate performance. Objects surviving these tests are classified as particles. The particle distributions are derived from the data base formed by these particles, their locations and features. Throughput of the off-line processing exceeds 500 MB/hr. This paper describes the reduction system, outlines the off-line processing procedure, summarizes the discrimination and correlation tests, and reports numerical results for a sample data set.

Tunnell, T.W.; Malone, R.M.; Fredericson, R.H.; DeLanoy, A.D.; Johnson, D.E.; Ciarcia, C.A. [Bechtel Nevada, Los Alamos Operations, Los Alamos, NM (United States); Sorenson, D.S. [Los Alamos National Lab., NM (United States)

1997-07-01

188

Deriving Particle Distributions from In-Line Fraunhofer Holographic Data  

SciTech Connect

Holographic data are acquired during hydrodynamic experiments at the Pegasus Pulsed Power Facility at the Los Alamos National Laboratory. These experiments produce a fine spray of fast-moving particles. Snapshots of the spray are captured using in-line Fraunhofer holographic techniques. Roughly one cubic centimeter is recorded by the hologram. Minimum detectable particle size in the data extends down to 2 microns. In a holography reconstruction system, a laser illuminates the hologram as it rests in a three-axis actuator, recreating the snapshot of the experiment. A computer guides the actuators through an orderly sequence programmed by the user. At selected intervals, slices of this volume are captured and digitized with a CCD camera. Intermittent on-line processing of the image data and computer control of the camera functions optimizes statistics of the acquired image data for off-line processing. Tens of thousands of individual data frames (30 to 40 gigabytes of data) are required to recreate a digital representation of the snapshot. Throughput of the reduction system is 550 megabytes per hour (MB/hr). Objects and associated features from the data are subsequently extracted during off-line processing. Discrimination and correlation tests reject noise, eliminate multiple counting of particles, and build an error model to estimate performance. Objects surviving these tests are classified as particles. The particle distributions are derived from the data base formed by these particles, their locations and features. Throughput of the off-line processing exceeds 500 MB/hr. This paper describes the reduction system, outlines the off-line processing procedure, summarizes the discrimination and correlation tests, and reports numerical results for a sample data set.

C.A. Ciarcia; D.E. Johnson; D.S. Sorenson; R.H. Frederickson, A.D. Delanoy; R.M. Malone; T.W. Tunnel

1997-08-01

189

Polarization of holographic grating diffraction. I. General theory.  

PubMed

The full polarization property of volume holographic grating diffraction is investigated theoretically. With a simple volume grating model, the diffracted fields and Mueller matrices are first derived from Maxwell's equations by using the Green's function algorithms. The formalism is derived for the general case that the diffraction beam and the grating wave vector are not in the plane of incidence, where s waves and p waves are not decoupled. The derived photon-momentum relations determine the Bragg angle selectivity. The parameters of diffraction strength related to the hologram-writing process and material are defined and are not necessarily small in general. The diffracted-beam profiles are analytically calculated by using the known grating shape function. This theory has provided a fundamental understanding of the polarization phenomena of a real holographic diffraction grating device. The derived algorithm would provide a simulation-analysis tool for the engineering design of real holographic beam combiner/splitter devices. PMID:15078023

Nee, Tsu-Wei; Nee, Soe-Mie F

2004-04-01

190

A funny thing happened on the way to the scanner: humor detection correlates with gray matter volume.  

PubMed

The detection and appreciation of humor is a complex cognitive process that remains poorly understood. Although functional neuroimaging studies have begun to map the brain systems involved in humor appreciation, there are virtually no data on the structural correlates between gray matter volume and this capacity. Using voxel-based morphometry, the present study examined the association between gray matter volume and the ability to detect and appreciate humor. Fifty-nine healthy adults aged 18-45 years (30 men) underwent structural MRI and completed the University of Pennsylvania Humor Appreciation Test (HAT). After controlling for age and sex, gray matter volume of the left inferior frontal gyrus, left temporal pole, and left insula correlated positively with the appreciation of visual and verbal humor on the HAT, whereas the gray matter volume of the right inferior frontal gyrus correlated only with verbal humor appreciation scores. There were no negative correlations between gray matter volume and HAT performance. These data support a neurobiological basis for humor appreciation, particularly involving left-hemispheric cortical systems, and further suggest that individual differences in humor appreciation may be related to differences in regional gray matter volume. PMID:23108043

Kipman, Maia; Weber, Mareen; Schwab, Zachary J; DelDonno, Sophie R; Killgore, William D S

2012-12-19

191

On the correlation between droplet volume and irradiation conditions in the laser forward transfer of liquids  

NASA Astrophysics Data System (ADS)

The analysis of the morphology of droplets printed through laser-induced forward transfer (LIFT) of liquid films shows that: (i) the droplet volume is linearly related with the energy of the laser pulse that originated it, (ii) the liquid ejection process is activated by an energy density threshold F 0, and (iii) the droplet volume can be correlated with a dimensional parameter of the laser beam through an oversimple model that states that the amount of printed liquid equals the liquid contained in the cylindrical portion of an irradiated film whose base corresponds to the cross-sectional area of the beam with energy density higher than F 0. Although these issues seem to describe correctly the LIFT process, some problematic instances arise from them. Thus, the linear relation between droplet volume and laser pulse energy seems to be inconsistent with the existence of the threshold F 0. On the other hand, the compatibility between the model and the aforementioned linear relation requires to be explained. Finally, the model is based on the idea that transfer takes place in a way analogous to the LIFT of solid films, but time-resolved imaging studies have demonstrated that liquid ejection follows a dynamics which seems quite unsuited with that idea. In this work previous results are re-analyzed and new experiments are performed in an attempt to clarify these questions. It is then shown that the inconsistencies pointed out are only apparent, and that the validity of the model is limited to irradiation conditions where the beam dimensions are significantly larger than the thickness of the liquid film. Furthermore, an explanation is provided for the dependence of the success and failure of the model on those irradiation conditions in terms of the diverse liquid ejection dynamics taking place.

Duocastella, M.; Patrascioiu, A.; Fernández-Pradas, J. M.; Morenza, J. L.; Serra, P.

2012-10-01

192

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

PubMed

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

2013-09-24

193

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

194

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

195

Scanning holographic lidar telescope  

Microsoft Academic Search

We have developed a unique telescope for lidar using a holographic optical element (HOE) as the primary optic. The HOE diffracts 532 nm laser backscatter making a 43 deg angle with a normal to its surface to a focus located 130 cm along the normal. The field of view scans a circle as the HOE rotates about the normal. The

Geary K. Schwemmer; Thomas D. Wilkerson

1993-01-01

196

Holographic fractional topological insulators  

SciTech Connect

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.

Hoyos, Carlos; Jensen, Kristan; Karch, Andreas [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States)

2010-10-15

197

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

198

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

2008-02-15

199

Holographic spectral selectors  

Microsoft Academic Search

The paper presents an analysis of hologram parameters required to obtain highly selective holographic spectral filers, both reflective and transmissive. For two particular cases of spectral filters recorded and operating at the wavelengths of 488 nm and 633 nm grating parameters were analyzed as functions of the recording geometry. The spectral selectivity as a function of layer thickness was also

Irina V. Semenova; Nadya O. Reinhand

1998-01-01

200

Holographic nondestructive testing  

Microsoft Academic Search

Holographic nondestructive testing (HNDT) is a high sensitivity, full field, noncontact, optical technique for observing the changes in the surface of a part as it deforms under stress. The stress can arise from the minute application of heat, pressure, torque, or vibration. The information obtained can be used as a design aid to locate and quantify areas undergoing strain and

D. Rosenthal; J. Trolinger

1995-01-01

201

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

202

Correlation between red blood cell transfusion volume and mortality in patients with massive blood transfusion: A large multicenter retrospective study  

PubMed Central

This study aimed to explore the correlation between red blood cell (RBC) transfusion volume and patient mortality in massive blood transfusion. A multicenter retrospective study was carried out on 1,601 surgical inpatients who received massive blood transfusion in 20 large comprehensive hospitals in China. According to RBC transfusion volume and duration, the patients were divided into groups as follows: 0–4, 5–9, 10–14, 15–19, 20–24, 25–29, 30–39 and ?40 units within 24 or 72 h. Mortality in patients with different RBC transfusion volumes was analyzed. It was found that patient mortality increased with the increase in the volume of RBC transfusion when the total RBC transfusion volume was ?10 units within 24 or 72 h. Survival analysis revealed significant differences in mortality according to the RBC transfusion volume (?2=72.857, P<0.001). Logistic regression analysis revealed that RBC transfusion volume is an independent risk factor [odds ratio (OR) = 0.52; confidence interval (CI): 0.43–0.64; P<0.01] for the mortality of patients undergoing a massive blood transfusion. When RBCs were transfused at a volume of 5–9 units within 24 and 72 h, the mortality rate was the lowest, at 3.7 and 2.3% respectively. It is concluded that during massive blood transfusion in surgical inpatients, there is a correlation between RBC transfusion volume within 24 or 72 h and the mortality of the patients. Patient mortality increases with the increase in the volume of RBC transfusion. RBC transfusion volume, the length of stay at hospital and intensive care unit stay constitute the independent risk factors for patient mortality.

YANG, JIANG-CUN; SUN, YANG; XU, CUI-XIANG; DANG, QIAN-LI; LI, LING; XU, YONG-GANG; SONG, YAO-JUN; YAN, HONG

2015-01-01

203

Ultra-High Density Holographic Memory Module with Solid-State Architecture  

NASA Technical Reports Server (NTRS)

NASA's terrestrial. space, and deep-space missions require technology that allows storing. retrieving, and processing a large volume of information. Holographic memory offers high-density data storage with parallel access and high throughput. Several methods exist for data multiplexing based on the fundamental principles of volume hologram selectivity. We recently demonstrated that a spatial (amplitude-phase) encoding of the reference wave (SERW) looks promising as a way to increase the storage density. The SERW hologram offers a method other than traditional methods of selectivity, such as spatial de-correlation between recorded and reconstruction fields, In this report we present the experimental results of the SERW-hologram memory module with solid-state architecture, which is of particular interest for space operations.

Markov, Vladimir B.

2000-01-01

204

Diffusion-weighted imaging in uterine artery embolisation: do findings correlate with contrast enhancement and volume reduction?  

PubMed Central

Objectives The objective of this study was to determine the role of diffusion-weighted imaging (DWI) in uterine artery embolisation (UAE), and to assess the apparent diffusion coefficient (ADC) of the dominant fibroid and its relationship to contrast enhancement and fibroid volume reduction. Methods We carried out a retrospective study of 15 patients who underwent UAE. Calculations were performed at baseline and 6 months post-embolisation. Fibroid ADC (expressed in 10?3 mm2 s?1) was calculated using b=0 and b=1000 DWI values. Fibroid enhancement was compared with background myometrium by measuring signal-difference-to-noise ratio (SDNR). Fibroid volume was calculated using a prolate ellipse formula. Results There was a significant reduction (p<0.001) in fibroid ADC at 6 months (0.48; standard deviation, SD=0.26) as compared with baseline (1.01; SD=0.39). No significant change (p=0.07) was identified in 6-month myometrial ADC (1.09; SD=0.28) as compared with baseline (1.24; SD=0.20). Moderately strong and significant positive correlation was identified between baseline ADC and 6-month percentage volume reduction of the fibroid (correlation=0.66, p=0.007). No correlation was identified between SDNR and ADC at baseline or 6 months (r=0.01, p=0.97 and r=?0.13, p=0.64, respectively) or SDNR and percentage volume reduction at 6 months (correlation r=0.18, p=0.51). Conclusion Baseline ADC of dominant fibroids shows a moderately strong correlation with subsequent volume reduction at 6 months following UAE. No correlation was identified between ADC values and contrast enhancement on the baseline or 6-month scans. Further prospective evaluation is needed before DWI can be utilised in clinical practice. Advances in knowledge DWI imaging may provide additional information about UAE and possibly help to predict uterine volume reduction. PMID:22898156

Ananthakrishnan, G; Macnaught, G; Hinksman, L; Gilmour, H; Forbes, K P; Moss, J G

2012-01-01

205

Holographic probes of collapsing black holes  

NASA Astrophysics Data System (ADS)

We continue the programme of exploring the means of holographically decoding the geometry of spacetime inside a black hole using the gauge/gravity correspondence. To this end, we study the behaviour of certain extremal surfaces (focusing on those relevant for equal-time correlators and entanglement entropy in the dual CFT) in a dynamically evolving asymptotically AdS spacetime, specifically examining how deep such probes reach. To highlight the novel effects of putting the system far out of equilibrium and at finite volume, we consider spherically symmetric Vaidya-AdS, describing black hole formation by gravitational collapse of a null shell, which provides a convenient toy model of a quantum quench in the field theory. Extremal surfaces anchored on the boundary exhibit rather rich behaviour, whose features depend on dimension of both the spacetime and the surface, as well as on the anchoring region. The main common feature is that they reach inside the horizon even in the post-collapse part of the geometry. In 3-dimensional spacetime, we find that for sub-AdS-sized black holes, the entire spacetime is accessible by the restricted class of geodesics whereas in larger black holes a small region near the imploding shell cannot be reached by any boundary-anchored geodesic. In higher dimensions, the deepest reach is attained by geodesics which (despite being asymmetric) connect equal time and antipodal boundary points soon after the collapse; these can attain spacetime regions of arbitrarily high curvature and simultaneously have smallest length. Higher-dimensional surfaces can penetrate the horizon while anchored on the boundary at arbitrarily late times, but are bounded away from the singularity. We also study the details of length or area growth during thermalization. While the area of extremal surfaces increases monotonically, geodesic length is neither monotonic nor continuous.

Hubeny, Veronika E.; Maxfield, Henry

2014-03-01

206

Conically scanned lidar telescope using holographic optical elements  

Microsoft Academic Search

Holographic optical elements (HOE) using volume phase holograms make possible a new class of lightweight scanning telescopes having advantages for lidar remote sensing instruments. So far, the only application of HOE's to lidar has been a non-scanning receiver for a laser range finder. We introduce a large aperture, narrow field of view (FOV) telescope used in a conical scanning configuration,

Geary K. Schwemmer; Thomas D. Wilkerson

1992-01-01

207

Glueball correlators as holograms  

E-print Network

We investigate the dynamical content of both hard- and soft-wall approximations to holographic QCD by deriving the corresponding glueball correlation functions and by confronting them with a variety of QCD results. We further calculate the glueball decay constants in both holographic duals, discuss emerging limitations and improvement strategies, and comment on a recent attempt to generalize the glueball correlator in the soft-wall background.

Forkel, Hilmar

2008-01-01

208

Glueball correlators as holograms  

E-print Network

We investigate the dynamical content of both hard- and soft-wall approximations to holographic QCD by deriving the corresponding glueball correlation functions and by confronting them with a variety of QCD results. We further calculate the glueball decay constants in both holographic duals, discuss emerging limitations and improvement strategies, and comment on a recent attempt to generalize the glueball correlator in the soft-wall background.

Hilmar Forkel

2008-08-03

209

Instant holographic portrait printing system  

Microsoft Academic Search

An instant holographic portrait printing system has been developed. The system consists of a capturing camera, a high-speed image processing device, and a desktop one-step holographic stereogram printer. It takes less than 3 minutes to obtain a horizontal parallax 3D image 78 mm X 59 mm on DuPont photopolymer film HRF700X071-20, including capturing and image processing time. Since the holographic

Akira Shirakura; Nobuhiro Kihara; Shigeyuki Baba

1998-01-01

210

High power holographic masks for beam shaping  

NASA Astrophysics Data System (ADS)

A new class of optically generated holographic projection masks is reported that shapes a high power laser beam into any number of image forming sub-beams. Unlike computer generated holograms or TIR volume holography approaches, the work reported here involves a phase only transmission in-line optical hologram to shape beams and image patterns on a workpiece. By combining the functions of beam homogenizer, mask and projection lens into a single in-line optical element, this approach yields a highly efficient but greatly simplified lithography system for ablation patterning. A lower cost ablation process tool with throughput 10-100 times that of existing tools is one result. This report examines the use of high power holographic projection masks to replace traditional reflective photomasks and the associated projection imaging optics currently used in laser ablation systems. A holographic projection mask also exhibits image redundancy, reducing the need for beam homogenization and increasing its resistance to print defects produced by contamination or damage.

Parker, William

2007-09-01

211

Development of high-efficiency holographic optical element for LED display  

NASA Astrophysics Data System (ADS)

In this paper, we present the development of full color holographic optical element for light-emitting diodes display application using a photopolymer. The reflection HOE was evaluated by measuring the diffraction efficiencies of holographic volume gratings recorded individually at 633 nm, 532 nm, and 473nm wavelengths. The spectral characterization of the holographic optical element, recorded using a combined single beam, and recorded using sequential beam, was carried out. Practical methods for fabrication of high efficiency holographic optical element by single layer photopolymer were developed. As the reconstruction light source of the hologram, light-emitting diodes of 632nm, 523nm and 465nm in wavelength was used. The results represent a strong confirmation that the special recording method using photopolymer can be employed in future commercial holographic applications.

Piao, Meilan; Gil, Sang-Keun; Lee, Kwon-Yeon; Kim, Nam

2014-02-01

212

Correlation Between Biomechanical Responses of Posterior Sclera and IOP Elevations During Micro Intraocular Volume Change  

PubMed Central

Purpose. This study tested the hypothesis that intraocular pressure (IOP) elevations, induced by controlled increase of intraocular volume, are correlated with the biomechanical responses of the posterior sclera. Methods. Porcine globes were tested within 48 hours postmortem. The first group of globes (n = 11) was infused with 15 ?L of phosphate-buffered saline at three different rates to investigate rate-dependent IOP elevations. The second group (n = 16) was first infused at the fast rate and then underwent inflation tests to investigate the relationship between IOP elevations (?IOP) and scleral strains. The strains in the superotemporal region of the posterior sclera were measured by ultrasound speckle tracking. Linear regression was used to examine the association between ?IOP due to micro-volumetric infusion and the scleral strains at a specific inflation pressure. Results. The average ?IOP was 14.9 ± 4.3 mm Hg for the infusion of 15 ?L in 1 second. The ?IOP was greater for the faster infusion rates but highly correlated across different rates (P < 0.001). A significant negative association was found between the ?IOP and the tangential strains in both the circumferential (R2 = 0.54, P = 0.003) and meridian (R2 = 0.53, P = 0.002) directions in the posterior sclera. Conclusions. This study showed a substantial increase in IOP, with a large intersubject variance during micro-volumetric change. A stiffer response of the sclera was associated with larger IOP spikes, providing experimental evidence linking corneoscleral biomechanics to IOP fluctuation. In vivo measurement of corneoscleral biomechanics may help better predict the dynamic profile of IOP. PMID:24130185

Morris, Hugh J.; Tang, Junhua; Cruz Perez, Benjamin; Pan, Xueliang; Hart, Richard T.; Weber, Paul A.; Liu, Jun

2013-01-01

213

Holographic in-line imaging setup for measuring the solid content of fluids  

NASA Astrophysics Data System (ADS)

Digital in-line holographic microscopy is a captivating imaging method for industrial applications where large volumes of fluids are to be imaged with microscopic resolution. The lensless holographic in-line imaging setup with a point light source, also known as the Gabor setup, can be built up with just a few, fairly low cost, components. In-line holography is well suited for imaging large volumes with a low concentration of scattering particles as most of the light emitted from the point source should pass through the image volume unscattered. The large depth of field of in-line holographic microscopy makes it possible to image larger volumes with comparable resolutions than what can be achieved with traditional light microscopy methods using low magnification objectives. Despite the many advantages gained over traditional microscopic methods by the use of holographic imaging for large volumes, so far it has only been widely utilized in biological and particle image velocimetry studies. The large depth of field of the holographic microscope permits simultaneous imaging of particles located at different depths without the need for mechanical scanning, and allows the use of large diameter fluidic channels which are not as prone to clogging and enable higher flow rates than smaller fluidic channels. In this paper, we present a digital in-line holographic microscope based measurement principle for measuring the solid particle content of fluids. The method proposed is demonstrated on bio-oil samples whose solid contents are less than 0.01 weight percentage.

Kaikkonen, Ville A.; Mäkynen, Anssi J.

2013-05-01

214

Worldline holographic Schwinger effect  

NASA Astrophysics Data System (ADS)

The decay of the vacuum due to the presence of an electric field is expected to be delayed by a confining force. We demonstrate that this feature is captured by our model for hadrons based on the worldline formalism. Our model, while based entirely in four-dimensional quantum field theory, shares many features with holographic approaches: it appears intrinsically quantum mechanical; as an auxiliary fifth dimension Schwinger's proper time combines with the physical four spacetime dimensions into an AdS5 geometry; conformal-symmetry breaking contributions lead to warping; hidden local symmetry emerges; four-dimensional sources are extended to five-dimensional fields by a Wilson flow (gradient flow); and a variational principle for this flow reproduces the corresponding holographic calculation. The approach also yields the higher-dimensional description in the nonrelativistic case.

Dietrich, Dennis D.

2014-08-01

215

Holographic Q-lattices  

NASA Astrophysics Data System (ADS)

We introduce a new framework for constructing black hole solutions that are holographically dual to strongly coupled field theories with explicitly broken translation invariance. Using a classical gravitational theory with a continuous global symmetry leads to constructions that involve solving ODEs instead of PDEs. We study in detail D = 4 Einstein-Maxwell theory coupled to a complex scalar field with a simple mass term. We construct black holes dual to metallic phases which exhibit a Drude-type peak in the optical conductivity, but there is no evidence of an intermediate scaling that has been reported in other holographic lattice constructions. We also construct black holes dual to insulating phases which exhibit a suppression of spectral weight at low frequencies. We show that the model also admits a novel AdS 3 × solution.

Donos, Aristomenis; Gauntlett, Jerome P.

2014-04-01

216

Holographic telescope arrays.  

PubMed

A typical job in optical computing is to illuminate an array of small nonlinear optical components, separated by wide gaps to avoid crosstalk. We do this by letting a wide uniform beam fall onto a densely packed array of minifying telescopes. Each telescope produces a narrow bundle of parallel rays which illuminates one of the nonlinear optical components. The holographic telescopes can do more than change the width of the bundles of parallel rays. Their image forming capability allows the transmission of many pixels per channel in parallel. The pair of lenslets of a single holographic telescope (Kepler or Galilean) is produced in rigid coupling. The monolithic production avoids adjusting the two lenslets later on. PMID:20531877

Lohmann, A W; Sauer, F

1988-07-15

217

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

218

Initiation of the transcriptional response to hyperosmotic shock correlates with the potential for volume recovery.  

PubMed

The control of activity and localization of transcription factors is critical for appropriate transcriptional responses. In eukaryotes, signal transduction components such as mitogen-activated protein kinase (MAPK) shuttle into the nucleus to activate transcription. It is not known in detail how different amounts of nuclear MAPK over time affect the transcriptional response. In the present study, we aimed to address this issue by studying the high osmolarity glycerol (HOG) system in Saccharomyces cerevisiae. We employed a conditional osmotic system, which changes the period of the MAPK Hog1 signal independent of the initial stress level. We determined the dynamics of the Hog1 nuclear localization and cell volume by single-cell analysis in well-controlled microfluidics systems and compared the responses with the global transcriptional output of cell populations. We discovered that the onset of the initial transcriptional response correlates with the potential of cells for rapid adaptation; cells that are capable of recovering quickly initiate the transcriptional responses immediately, whereas cells that require longer time to adapt also respond later. This is reflected by Hog1 nuclear localization, Hog1 promoter association and the transcriptional response, but not Hog1 phosphorylation, suggesting that a presently uncharacterized rapid adaptive mechanism precedes the Hog1 nuclear response. Furthermore, we found that the period of Hog1 nuclear residence affects the amplitude of the transcriptional response rather than the spectrum of responsive genes. PMID:23758973

Geijer, Cecilia; Medrala-Klein, Dagmara; Petelenz-Kurdziel, Elzbieta; Ericsson, Abraham; Smedh, Maria; Andersson, Mikael; Goksör, Mattias; Nadal-Ribelles, Mariona; Posas, Francesc; Krantz, Marcus; Nordlander, Bodil; Hohmann, Stefan

2013-08-01

219

SPDC correlated photon source filtered for narrowed bandwidth using volume Bragg grating  

NASA Astrophysics Data System (ADS)

A Volume Bragg Grating (VBG) can be used to efficiently extract a narrow bandwidth, highly collimated beam from an otherwise broad spectrum beam. We use a VBG to extract a narrow bandwidth of signal spectrum from a broadband Spontaneous Parametric Down-Conversion source to optimally match the narrow detection bandwidth of our idler upconversion detector. Improved coincidence count rates and visibility can be achieved when limiting signal-spectrum detection to the narrow signal bandwidth whose photons are correlated with a narrow idler-spectrum bandwidth that has been selected by the up-conversion detector. We compare coincidence count rate and visibility for when the entire signal spectrum is detected and when the spectrum has been filtered by the VBG. We further relax the collection techniques and show that following the VBG, the coincidence count rate improves with minimal loss in visibility compared to when the entire spectrum is detected. We introduce our initial efforts at using the VBG to further narrow the signal spectrum by placing it inside a multipass cavity. Additionally, we further adapt the single photon level up-conversion spectrometer, previously developed for idler spectrum measurement, to indirectly measure the single photon level signal spectrum. We verify its capability for several different wavelength and linewidth selections.

Slattery, Oliver; Kuo, Paulina; Kim, Yong-Su; Ma, Lijun; Tang, Xiao

2012-10-01

220

SABER NO+(v) Volume Emission Rates and Magnetic Indices Correlation Comparisons for Magnetic Storm Events  

NASA Astrophysics Data System (ADS)

The TIMED/SABER instrument is a broadband emission radiometer with ten channels that measure limb emission from the MLTI region. Of particular interest for this study is the use of nighttime auroral 4.3 um limb emission, which is primarily due to vibrationally excited NO+, caused by ion-neutral chemical reactions. From the SABER 4.3 um limb emission measurements, the NO+(v) Volume Emission Rate (VER) is derived by removing the background CO2 radiance contribution using SABER-based non-LTE radiation transfer models, and by performing a standard Abel inversion on the residual radiance. SABER observations show that NO+(v) VER is significantly enhanced during magnetic storms and can be used as a proxy to correct the International Reference Ionosphere (IRI) model E-region electron density for magnetic storm events. The correction procedure uses an impulse response function which is convolved with an appropriate geomagnetic driver index. The result in a correction factor that will scale the nominal IRI model E-region electron density. In order to determine the appropriate magnetic driver index, we study the cross correlations between SABER NO+(v) VER and different geomagnetic driver indices such as HP, Kp, Ap, AE, and Dst for different magnetic storm events.

Fernandez, J. R.; Mertens, C. J.; Bilitza, D.; Xu, X.; Russell, J. M.; Mlynczak, M. G.

2008-05-01

221

Holographic subsonic flow visualization.  

PubMed

A pulsed ruby laser holographic interferometer was used to detect density gradients in the airflow around an airfoil at subsonic speeds in a low speed wind tunnel. These experiments proved that vibration of the optical components or object between exposures of the interferometric hologram does not destroy the detection of density gradients but actually can aid in the flow visualization. The density gradients determined from the fringe pattern analysis are consistent with the anticipated flow pattern. PMID:20094197

Reinheimer, C J; Wiswall, C E; Schmiege, R A; Harris, R J; Dueker, J E

1970-09-01

222

Holographic glucose sensors  

Microsoft Academic Search

A novel holographic sensor system capable of detecting dynamic changes in glucose concentration has been developed. The hologram is recorded within a bio-compatible hydrogel matrix containing phenylboronic acid derivatives. On binding glucose, the colour of the hologram red-shifts to longer wavelengths as the hydrogel expands and this colour change is used to quantify glucose concentration. However, phenylboronic acids are non-selective

Satyamoorthy Kabilan; Alexander J. Marshall; Felicity K. Sartain; Mei-Ching Lee; Abid Hussain; Xiaoping Yang; Jeff Blyth; Njeri Karangu; Karen James; Jimmy Zeng; Dawn Smith; Angelika Domschke; Christopher R. Lowe

2005-01-01

223

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

2009-07-16

224

Sediment Core Correlation and Mapping of Sediment Accumulation Rates in Lake Geneva (Switzerland, France) Using Volume Magnetic Susceptibility  

Microsoft Academic Search

Studies of the relation between a lake and its watershed often need an accurate knowledge of sediment accumulation rates over large areas. We report here the combined method of sediment core correlation through Volume Magnetic Susceptibility profiles and sediment absolute dating, which permits drawing sediment accumulation rate maps. The Rhone River is the principal tributary to Lake Geneva, both in

Jean-Luc Loizeau; Janusz Dominik; Tiziana Luzzi; Jean-Pierre Vernet

1997-01-01

225

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

226

MINACE filter: variants of realization in 4-f correlator  

NASA Astrophysics Data System (ADS)

Minimum Noise And Correlation Energy (MINACE) filters application provides good ability to recognize in case of grayscale input images of an object with background noises. For fast correlation matching MINACE filters can be used in 4-f correlators as a computer generated hologram (holographic filters). In this paper different variants of holographic filters realization were discussed. The results of correlation recognition with holographic MINACE filters are presented.

Shaulskiy, Dmitry V.; Evtikhiev, Nikolay N.; Starikov, Rostislav S.; Starikov, Sergey N.; Zlokazov, Evgeny Y.

2014-04-01

227

Correlation  

Microsoft Academic Search

Reviews 16 publications (1913-1914) based on the problem of correlations. Correlation is viewed as a means of solving the problem of development and the traits that are affected. The uses of correlations are also discussed. A high correlation does not signify good quality of the two factors. A more intensive study of the factors influencing correlation is recommended. Cites a

James Burt Miner

1914-01-01

228

Correlation  

Microsoft Academic Search

Reviews 38 studies on statistical correlation (1913-1916). Several studies have tried to explain and investigate Spearman's theory of general and specific mental factors in terms of correlation. The interpretation of correlation through heredity has also been discussed by investigators. A number of methods such as partial and multiple correlations, variant difference correlation method, and several others have been devised. The

James Burt Miner

1916-01-01

229

Method and apparatus for holographic wavefront diagnostics  

DOEpatents

A wavefront diagnostic apparatus has an optic and a measuring system. The optic forms a holographic image in response to a beam of light striking a hologram formed on a surface of the optic. The measuring system detects the position of the array of holographic images and compares the positions of the array of holographic images to a reference holographic image.

Toeppen, John S. (Livermore, CA)

1995-01-01

230

Method and apparatus for holographic wavefront diagnostics  

DOEpatents

A wavefront diagnostic apparatus has an optic and a measuring system. The optic forms a holographic image in response to a beam of light striking a hologram formed on a surface of the optic. The measuring system detects the position of the array of holographic images and compares the positions of the array of holographic images to a reference holographic image. 3 figs.

Toeppen, J.S.

1995-04-25

231

Potential and limits of holographic reconstruction algorithms  

SciTech Connect

For the purpose of ultrasonic nondestructive testing of materials, holography in connection with digital reconstruction algorithms has been proposed as a modern tool to extract crack sizes from ultrasonic scattering data. DEfining the typical holographic reconstruction algoithm as the application of the scalar Kirchhoff diffraction theory to backward wave propagation, we demonstrate its general incapability of reconstructing equivalent sources, and hence, geometries of scattering bodies. Only the special case of a planar measurement recording surface, that is to say, a hologram plane, and a planar crack with perfectly rigid boundary conditions parallel to the hologram plane and perpendicular to the incident field yields a nearly perfect correlation between rack, size and reconstructed image; the reconstruction algorithm is then referred to as the Rayleigh-Sommerfeld formula; it therefore represents the optimal case matched to that special geometrical situation and, hence, may be interpreted as a quasi-matched spatial filter. Using integral equation theory and physical optics, we compute synthetic holographic data for a linear cracklike scarterer for both plane and spherical wave incidence, the latter case simulating a synthetic aperture impulse echo situation, thus illustrating how the Rayleigh-Sommerfeld algorithm or its Fresnel approximation increasingly fail for cracks inclined to the hologram plane and excited nonperpendicularly. Furthermore, we point out how the physical data recording process may additionally influence the reconstruction accuracy, and, finally, guidelines for a careful and serious application of these holographic reconstruction algorithms are given. The theroretical results are supported by measurements.

Berger, M.; Bruck, D.; Fiocher, M.; Langenberg, K.J.; Oberst, J.; Schmitz, V.

1981-06-01

232

Nondestructive testing by holographic interferometry  

Microsoft Academic Search

Conditions for the application of holographic interferometry as a means of nondestructive evaluation are discussed. Following a brief review of the principles of holographic interferometry, factors influencing the quality of the hologram are examined, with attention given to the parameters of the laser light source, the photographic plates, image reconstruction, the optical elements and the mechanical stability of the apparatus.

A. Piodi

1979-01-01

233

Digital color management in full-color holographic three-dimensional printer.  

PubMed

We propose a new method of color management for a full-color holographic, three-dimensional (3D) printer, which produces a volume reflection holographic stereogram using red, green, and blue three-color lasers. For natural color management in the holographic 3D printer, we characterize its color reproduction characteristics based on the spectral measurement of reproduced light. Then the color conversion formula, which comprises a one-dimensional lookup table and a 3×3 matrix, was derived from the measurement data. The color reproducibility was evaluated by printing a color chart hologram, and the average CIELAB ?E=13.19 is fairly small. PMID:22772106

Yang, Fei; Murakami, Yuri; Yamaguchi, Masahiro

2012-07-01

234

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

235

Correlation  

Microsoft Academic Search

Reviews 7 studies in the area of interpretation of correlation from the psychological point of view. The limitations and meanings of correlation methods have also been given. The statistical methods of calculating correlation, as given by 8 psychologists have been reported. Presents 22 reports, given by various psychologists, who have evaluated the tests using various correlation methods. Six studies were

James Burt Miner

1919-01-01

236

Two-step phase-shifting fluorescence incoherent holographic microscopy.  

PubMed

Fluorescence holographic microscope (FINCHSCOPE) is a motionless fluorescence holographic imaging technique based on Fresnel incoherent correlation holography (FINCH) that shows promise in reconstructing three-dimensional fluorescence images of biological specimens with three holograms. We report a developing two-step phase-shifting method that reduces the required number of holograms from three to two. Using this method, we resolved microscopic fluorescent beads that were three-dimensionally distributed at different depths with two interferograms captured by a CCD camera. The method enables the FINCHSCOPE to work in conjunction with the frame-straddling technique and significantly enhance imaging speed. PMID:24972355

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

2014-06-01

237

Two-step phase-shifting fluorescence incoherent holographic microscopy  

NASA Astrophysics Data System (ADS)

Fluorescence holographic microscope (FINCHSCOPE) is a motionless fluorescence holographic imaging technique based on Fresnel incoherent correlation holography (FINCH) that shows promise in reconstructing three-dimensional fluorescence images of biological specimens with three holograms. We report a developing two-step phase-shifting method that reduces the required number of holograms from three to two. Using this method, we resolved microscopic fluorescent beads that were three-dimensionally distributed at different depths with two interferograms captured by a CCD camera. The method enables the FINCHSCOPE to work in conjunction with the frame-straddling technique and significantly enhance imaging speed.

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

2014-06-01

238

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

239

Plasma vascular endothelial but not fibroblast growth factor levels correlate with colorectal liver metastasis vascularity and volume  

PubMed Central

The extent to which plasma levels of angiogenic factors in healthy individuals and tumour volume-related variations in colorectal cancer affect the accuracy of circulating angiogenic factors as predictors of colorectal cancer vascularity is unknown. We used enzyme-linked immunosorbant assay to measure plasma vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) levels in colorectal liver metastasis (CLM) patients, and ‘no cancer’ controls. CLM volume was determined from computerized tomography scans, and tumour vessel count and vessel volume from anti-endothelial antibody-stained biopsies. There was a significant (P = 0.03) increase in plasma VEGF level in 29 CLM patients (median 180.3 pg ml?1, iqr 132.5–284.8 pg ml?1) compared with 19 controls (median 125.8 pg ml?1, iqr 58.2–235.9 pg ml?1). There were significant correlations between plasma VEGF and tumour vessel count (r = 0.66, P = 0.03), tumour vessel volume (r = 0.59, P = 0.03), and CLM volume (r = 0.53, P = 0.03). A VEGF level in the upper quartile of the plasma VEGF distribution had a 70% sensitivity and 75% specificity in predicting an upper quartile liver metastasis tumour vessel count. No relation was identified between CLM and plasma bFGF levels. Plasma VEGF level predicted CLM vascularity, despite an overlap with normal levels and tumour volume-related variations. © 2000 Cancer Research Campaign PMID:10737380

Davies, M M; Jonas, S K; Kaur, S; Allen-Mersh, T G

2000-01-01

240

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

241

Holographic model of hadronization.  

PubMed

We study hadronization of the final state in a particle-antiparticle annihilation using a holographic gravity dual description of QCD. At the point of hadronization we match the events to a simple (Gaussian) energy distribution in the five dimensional theory. The final state multiplicities are then modeled by calculating the overlap between the Gaussian and a set of functions in the fifth dimension which represent each hadron. We compare our results to those measured in e(+)e(-) collisions. Hadron production numbers over a range of 4 orders of magnitude are reproduced well. PMID:18518189

Evans, Nick; Tedder, Andrew

2008-04-25

242

Holographic surveillance radar  

NASA Astrophysics Data System (ADS)

Since the 1940s, radar development has focused on narrow-beam, scanning sensors. A wide field of view has advantages in terms of extended acquisition time for any target, and when combined with a high Doppler sampling frequency can yield high-resolution Doppler spectra. Unambiguous range and Doppler can be achieved under certain circumstances, resulting in enhanced ability to evaluate the characteristics of targets and clutter. Holographic radar has a range of applications in which the ability to discriminate targets among clutter is key. An example of such an application is in mitigation of wind farm interference with Air Traffic Control radar.

Oswald, Gordon K. A.

2009-05-01

243

Holographic s +p superconductors  

NASA Astrophysics Data System (ADS)

We study the phase diagram of a holographic model realizing a U(2) global symmetry on the boundary and show that at low temperature a phase with both scalar s and vector p condensates exists. This is the s +p-wave phase where the global U(2) symmetry and also the spatial rotational symmetry are spontaneously broken. By studying the free energy we show that this phase is preferred when it exists. We also consider unbalanced configurations where a second chemical potential is turned on. They present a rich phase diagram characterized by the competition and coexistence of the s and p order parameters.

Amado, Irene; Areán, Daniel; Jimenez-Alba, Amadeo; Melgar, Luis; Salazar Landea, Ignacio

2014-01-01

244

Holographic quantum computing.  

PubMed

We propose to use a single mesoscopic ensemble of trapped polar molecules for quantum computing. A "holographic quantum register" with hundreds of qubits is encoded in collective excitations with definite spatial phase variations. Each phase pattern is uniquely addressed by optical Raman processes with classical optical fields, while one- and two-qubit gates and qubit readout are accomplished by transferring the qubit states to a stripline microwave cavity field and a Cooper pair box where controllable two-level unitary dynamics and detection is governed by classical microwave fields. PMID:18764313

Tordrup, Karl; Negretti, Antonio; Mølmer, Klaus

2008-07-25

245

Biopolymer holographic diffraction gratings  

NASA Astrophysics Data System (ADS)

Surface-relief diffraction gratings are holographically recorded in dextran sensitized with ammonium dichromate (DCD). DCD was exposed with single-frequency 200 mW diode pumped ND-YAG laser, at 532 nm. The diffraction grating profiles were analyzed by atomic force microscopy (AFM). It was found that different surface profiles could be obtained. Gratings with 330 lines/mm spatial frequencies were made. Existence of higher harmonics in Fourier Transform of non-sinusoidal profiles shows that DCD is capable of recording spatial frequencies up to 1320 lines/mm (four times fundamental frequency). The measured maximum relief depth of the DCD grating is 402 nm.

Savi? Ševi?, Svetlana; Panteli?, Dejan

2008-03-01

246

Holographic nondestructive testing  

SciTech Connect

Holographic nondestructive testing (HNDT) is a high sensitivity, full field, noncontact, optical technique for observing the changes in the surface of a part as it deforms under stress. The stress can arise from the minute application of heat, pressure, torque, or vibration. The information obtained can be used as a design aid to locate and quantify areas undergoing strain and as a quality control aid to identify structural flaws such as internal flaws or delaminations. HNDT is also used to identify and measure vibrational modes.

Rosenthal, D.; Trolinger, J. [MetroLaser, Irvine, CA (United States)

1995-12-01

247

Holographic models for undoped Weyl semimetals  

E-print Network

We continue our recently proposed holographic description of single-particle correlation functions for four-dimensional chiral fermions with Lifshitz scaling at zero chemical potential, paying particular attention to the dynamical exponent z = 2. We present new results for the spectral densities and dispersion relations at non-zero momenta and temperature. In contrast to the relativistic case with z = 1, we find the existence of a quantum phase transition from a non-Fermi liquid into a Fermi liquid in which two Fermi surfaces spontaneously form, even at zero chemical potential. Our findings show that the boundary system behaves like an undoped Weyl semimetal.

Umut Gursoy; Vivian Jacobs; Erik Plauschinn; Henk Stoof; Stefan Vandoren

2012-09-12

248

A simple holographic model of momentum relaxation  

NASA Astrophysics Data System (ADS)

We consider a holographic model consisting of Einstein-Maxwell theory in d + 1 bulk spacetime dimensions with d - 1 massless scalar fields. Momentum relaxation is realised simply through spatially dependent sources for operators dual to the neutral scalars, which can be engineered so that the bulk stress tensor and resulting black brane geometry are homogeneous and isotropic. We analytically calculate the DC conductivity, which is finite. In the d = 3 case, both the black hole geometry and shear-mode currentcurrent correlators are those of a sector of massive gravity.

Andrade, Tomás; Withers, Benjamin

2014-05-01

249

Holographic models for undoped Weyl semimetals  

NASA Astrophysics Data System (ADS)

We continue our recently proposed holographic description of single-particle correlation functions for four-dimensional chiral fermions with Lifshitz scaling at zero chemical potential, paying particular attention to the dynamical exponent z = 2. We present new results for the spectral densities and dispersion relations at non-zero momenta and temperature. In contrast to the relativistic case with z = 1, we find the existence of a quantum phase transition from a non-Fermi liquid into a Fermi liquid in which two Fermi surfaces spontaneously form, even at zero chemical potential. Our findings show that the boundary system behaves like an undoped Weyl semimetal.

Gürsoy, Umut; Jacobs, Vivian; Plauschinn, Erik; Stoof, Henk; Vandoren, Stefan

2013-04-01

250

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

251

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

252

Titers of herpes simplex virus type 1 antibodies positively correlate with grey matter volumes in Alzheimer's disease.  

PubMed

HSV-1 infection of the central nervous system targets the same brain regions most affected in Alzheimer's disease (AD) and could play a pathogenic role in AD. HSV-1 serum IgG titers were analyzed in patients with mild AD (n = 83) and healthy controls (HC, n = 51); results were correlated with cortical grey matter (GM) volumes as analyzed by MRI. Seroprevalence and antibody (Ab) titers were comparable between AD and HC; elevated Ab titers (>75th percentile) were nevertheless significantly more frequent in AD and were positively correlated with cortical bilateral temporal and orbitofrontal GM volumes. HSV-1-specific-Ab could possibly play a protective role in the early stages of AD. PMID:24072067

Mancuso, Roberta; Baglio, Francesca; Cabinio, Monia; Calabrese, Elena; Hernis, Ambra; Nemni, Raffaello; Clerici, Mario

2014-01-01

253

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

254

Do skeletal cephalometric characteristics correlate with condylar volume, surface and shape? A 3D analysis  

PubMed Central

Objective The purpose of this study was to determine the condylar volume in subjects with different mandibular divergence and skeletal class using cone-beam computed tomography (CBCT) and analysis software. Materials and methods For 94 patients (46 females and 48 males; mean age 24.3?±?6.5?years), resultant rendering reconstructions of the left and right temporal mandibular joints (TMJs) were obtained. Subjects were then classified on the base of ANB angle the GoGn-SN angle in three classes (I, II, III) . The data of the different classes were compared. Results No significant difference was observed in the whole sample between the right and the left sides in condylar volume. The analysis of mean volume among low, normal and high mandibular plane angles revealed a significantly higher volume and surface in low angle subjects (p?volume and surface than class I and class II subjects, although the difference was not significant. Conclusions Higher condylar volume was a common characteristic of low angle subjects compared to normal and high mandibular plane angle subjects. Skeletal class also appears to be associated to condylar volume and surface. PMID:22587445

2012-01-01

255

Baryonic matter in holographic QCD  

E-print Network

We study baryons and baryonic matter in holographic QCD with $D4/D8/\\bar{D8}$ multi-$D$ brane system. In large-$N_c$ holographic QCD, the baryon appears as a topologically non-trivial chiral soliton, which is called ``brane-induced Skyrmion''. We also analyze the features of the baryonic matter in holographic QCD by investigating the system of single brane-induced Skyrmion on a three-dimensional closed manifold $S^3$. We propose a new interesting picture of ``pion dominance'' near the critical density.

Kanabu Nawa; Hideo Suganuma; Toru Kojo

2008-06-18

256

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

257

Dual wavelength holographic interferometry system  

NASA Technical Reports Server (NTRS)

A two-wave holographic interferometry system and method is described. In such systems, a reference beam holographic is superimposed on an object beam, the object beam being an image obtained by passing a beam through an object regarding which some parameter (e.g., temperature gradient) is to be measured. A photograph of the superimposed beams is taken. This invention employs two object and two reference beams and the invention is particularly concerned with the use of a prism assembly which causes the two different wavelengths of the object beams to emerge from the prism at slightly different angles, thereby providing two holographic images which are slightly displaced from each other.

Witherow, William K. (inventor); Ecker, Andreas (inventor)

1988-01-01

258

Correlation  

NSDL National Science Digital Library

The applets, created by Virginia Tech's Department of Statistics, allow you to see how different bivariate data look under different correlation structures. The "Movie" applet either creates data for a particular correlation or animates a multitude data sets ranging correlations from -1 to 1. The "Creation" applet allows the user to create a data set by adding or deleting points from the screen.

Anderson-Cook, C.; Dorai-Raj, S.; Robinson, T.

2009-09-14

259

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

260

New holographic overlays  

NASA Astrophysics Data System (ADS)

This paper discusses a new type of holographic overlay, FLASHPRINT, which may be used in both security and packaging applications. Unlike the more common embossed holograms currently used, FLASHPRINT leads to reduced set-up costs and offers a simpler process. This reduces the long lead times characteristic of the existing technology and requires the customer to provide only two-dimensional artwork. The overlay material contains a covert 2-D image. The image may be switched on or off by simply tilting the overlay in a light source. The overlay is replayed in the 'on' position to reveal the encoded security message as a highly saturated gold colored image. This effect is operable for a wide range of lighting conditions and viewing geometries. In the 'off' position the overlay is substantially transparent. These features make the visual effect of the overlay attractive to incorporate into product design. They may be laminated over complex printed artwork such as labels and security passes without masking the printed message. When switched 'on' the image appears both sharp and more than seven times brighter than white paper. The image remains sharp and clear even in less favorable lighting conditions. Although the technique offers a low set-up cost for the customer, through its simplicity, it remains as technically demanding and difficult to counterfeit as any holographic process.

Hopwood, Anthony I.

1991-10-01

261

The correlation of the spraying volume with herbicide adherence and herbicide penetration in glyphosate treatments.  

PubMed

The relationship between the spraying volume and glyphosate effectiveness has been widely studied over the years. Likewise, the effect of different adjuvants on glyphosate leaf adherence/penetration is currently well understood. However, not much is known about the way spraying volumes may influence these two herbicide properties or, in other words, which factor (adherence or penetration) is the limiting factor when spraying at low or high volumes of treatment. Using grass-weed Lolium rigidum and broad-leaved weed Portulaca oleracea as experimental systems, the effect of low (200 L ha(-1)) and high (800 L ha(-1)) spraying volumes and six commercial adjuvants (poly-l-p-menthene, a mixture of methyl oleate and palmitate, alkylglycol ester, dodecylbenzene ammonium sulphonate, and two paraffinic oils) plus ammonium sulfate on the effectiveness of five commercial glyphosate formulations has been studied under laboratory controlled conditions. Dose-response assays showed significant differences between low and high spraying volume treatments as expected, the former being much more effective than the latter. However, and in all commercial formulations and weed species tested, the best results at low spraying volumes were always obtained when formulating glyphosate with oils or their derivatives, with a minimal improvement observed in glyphosate/surfactant mixtures. On the contrary, both the use of ionic or non-ionic surfactants as glyphosate adjuvants gave the best results at high spraying volumes, with only a marginal success observed on paraffinic oils and fatty acidesters. Data point out glyphosate absorption as being a two-step process made up of adherence first and then penetration, both events being essential for glyphosate effectiveness. Under these terms, high performance glyphosate-rich low spraying volumes succeed by themselves in soaking leaf surfaces, penetration therefore being the main and only limiting factor, while low performance glyphosate-poor high spraying volumes fail to either soak or penetrate leaf cuticles. The use of penetrative agents such as oils is therefore advised as a single method to increase glyphosate effectiveness at low spraying volumes, whereas glyphosate treatments at high spraying volumes are better improved by using surfactant agents or surfactant + oil mixtures. PMID:15756875

Menéndez, J; Bastida, F

2004-01-01

262

Adventures in holographic dimer models  

NASA Astrophysics Data System (ADS)

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; Karch, Andreas; Yaida, Sho

2011-03-01

263

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

264

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

265

Digital holographic imaging of microorganisms  

E-print Network

Imaging aquatic microorganisms in 3D space is of interest to biologists and ocean scientists seeking to understand the behavior of these organisms in their natural environments. In this research, digital holographic imaging ...

Wolf, Michael Trevor

2006-01-01

266

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

267

A holographic charged preon model  

E-print Network

The Standard Model (SM) is a successful approach to particle physics calculations. However, there are indications that the SM is only a good approximation to an underlying non-local reality involving fundamental entities (preons) that are not point particles. Furthermore, our universe seems to be dominated by a vacuum energy/cosmological constant. The holographic principle then indicates only a finite number of bits of information will ever be available to describe the observable universe, and that requires a holographic preon model linking the (0,1) holographic bits to SM particles. All SM particles have charges 0, 1/3, 2/3 or 1 in units of the electron charge, so the bits in a holographic preon model must be identified with fractional electric charge. Such holographic charged preon models require baryon asymmetry and also suggest a mechanism for stationary action. This paper outlines a holographic charged preon model where preons are strands with finite energy density specified by bits of information identifying the charge on each end. In the model, SM particles consist of three strands with spin states corresponding to wrapped states of the strands. SM particles in this wrapped preon model can be approximated by preon bound states in non-local dynamics based on three-preon Bethe-Salpeter equations with instantaneous three-preon interactions. The model can be falsified by data from the Large Hadron Collider because it generates baryon asymmetry without axions, and does not allow more than three generations of SM fermions.

T. R. Mongan

2008-01-23

268

Correlation between volume change and cell voltage variation with composition for lithium intercalated amorphous films.  

PubMed

Interactions between the intercalant and the host have been studied in homogeneous amorphous Li(x)WO3 prepared by electron beam evaporation, using electrochemical experiments with films of different thickness (100-400 nm). We have related the intercalation thermodynamics, described previously by us [Solid State Ionics 2005, 176, 1701] with other models that take into account film volume dilatation along the intercalation. A distinct behavior of cell voltage variation with composition and volume change is observed for the thinnest (100 nm) films: cell voltage follows ideal insertion thermodynamics and no deformation was detected using profilometry techniques. In contrast, thicker films exhibited both volume changes and, correspondingly, cell voltage departs from ideality due to contributions to the chemical potential arising from elastic distortions of the host matrix. PMID:16526675

Garcia-Belmonte, Germà; García-Cañadas, Jorge; Bisquert, Juan

2006-03-16

269

Correlation  

Microsoft Academic Search

Reviews 32 papers on correlation its methods, interpretation and application. Highlights the contributions of K. Pearson, B. Hart and C. Spearman, and W. H. Winch. W. Betz's publications concludes that correlation alone does not demonstrate a functional connection and serves the purpose of (1) describing educational or social descriptions of Large groups, and (2) discovering functional connections when used with

James Burt Miner

1912-01-01

270

Correlation  

Microsoft Academic Search

Discusses: (1) the need for a general factor to explain the correlation between tested psychophysical processes and (2) the importance of multiple correlation in solving the complex problems. Reports the contributions of Thurstone, Ruml and Kelley to the methods of calculation of coefficients. Doll offers new ways of using corrections. Applications of this method in new fields other than applied

James Burt Miner

1917-01-01

271

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

272

Holographic versatile disc system  

NASA Astrophysics Data System (ADS)

A Holographic Versatile Disc (HVD) system, using Collinear Technologies for a high capacity and high data transfer rates storage system, is proposed. With its unique configuration the optical pickup can be designed as small as a DVD's, and can be placed on one side of the disc. With the HVD's special structure, the system can servo the focus/track and locate reading/writing address. A unique selectable capacity recording format of HVD and its standardization activity are also introduced. Experimental and theoretical studies suggest that the tilt, wavelength, defocus and de-track margins are wide enough to miniaturize the HVD system at a low cost. HVD systems using Collinear Technologies will be compatible with existing disc storage systems, like CD and DVD, and will enable us to expand its applications into other optical information storage systems.

Horimai, Hideyoshi; Tan, Xiaodi

2005-09-01

273

On holographic defect entropy  

NASA Astrophysics Data System (ADS)

We study a number of (3 + 1)- and (2 + 1)-dimensional defect and boundary conformal field theories holographically dual to supergravity theories. In all cases the defects or boundaries are planar, and the defects are codimension-one. Using holography, we compute the entanglement entropy of a (hemi-)spherical region centered on the defect (boundary). We define defect and boundary entropies from the entanglement entropy by an appropriate background subtraction. For some (3 + 1)-dimensional theories we find evidence that the defect/boundary entropy changes monotonically under certain renormalization group flows triggered by operators localized at the defect or boundary. This provides evidence that the g-theorem of (1 + 1)-dimensional field theories generalizes to higher dimensions.

Estes, John; Jensen, Kristan; O'Bannon, Andy; Tsatis, Efstratios; Wrase, Timm

2014-05-01

274

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

2009-03-03

275

Shifted reference holographic interferometry.  

PubMed

Conventional holographic interferometry of vibrating objects yields reconstructed images in which the radiance of each point is proportional to the square of the zero-order Bessel function of an argument proportional to the vibration amplitude. Therefore, the vibration pattern appears as a dark outline on the bright background of the nonvibrating points. By appropriately shifting the frequency of the reference radiation used in the recording of the hologram, the radiance of each image point can be made proportional to the square of the first-order Bessel function of the above argument. Nonvibrating points are therefore black and vibrating points appear bright on a black background. A quantitative analysis of the technique is reviewed and extended and shows the shifted-reference method to be almost one order of magnitude more sensitive than the conventional method. Experimental verification of the theory is presented and some possible future applications are indicated. PMID:20125577

Zambuto, M H; Fischer, W K

1973-07-01

276

MRI Features in a Canine Model of Ischemic Stroke: Correlation between Lesion Volume and Neurobehavioral Status during the Subacute Stage  

PubMed Central

The purpose of this study was to evaluate the diagnostic value of magnetic resonance imaging (MRI) and assess the correlation between the volume of the ischemic lesion and neurobehavioral status during the subacute stage of ischemic stroke. Ischemic stroke was induced in 6 healthy laboratory beagles through permanent occlusion of the middle cerebral artery (MCAO). T2-weighted and fluid-attenuated inversion recovery (FLAIR) imaging, diffusion-weighted imaging (DWI), measurement of the apparent diffusion coefficient (ADC) ratio, and neurobehavioral evaluation were performed 3 times serially by using a 1.5-T MR system: before and 3 and 10 d after MCAO. Ischemic lesions demonstrated T2 hyperintensity, FLAIR hyperintensity, and DWI hyperintensity. The ADC ratio was decreased initially but then was increased at 10 d after MCAO. Ischemic lesion volumes on T2-weighted and FLAIR imaging were not significantly different from those on DWI. The lesion volume and neurobehavioral score showed strong correlation. Our results suggest that conventional MRI may be a reliable diagnostic tool during the subacute stage of canine ischemic stroke. PMID:19887030

Kang, Byeong-Teck; Jang, Dong-Pyo; Gu, Su-Hyun; Lee, Jong-Hwan; Jung, Dong-In; Lim, Chae-Young; Kim, Ha-Jung; Kim, Young-Bo; Kim, Hyung-Joong; Woo, Eung-Je; Cho, Zang-Hee; Park, Hee-Myung

2009-01-01

277

Compact Holographic Data Storage  

NASA Technical Reports Server (NTRS)

NASA's future missions would require massive high-speed onboard data storage capability to Space Science missions. For Space Science, such as the Europa Lander mission, the onboard data storage requirements would be focused on maximizing the spacecraft's ability to survive fault conditions (i.e., no loss in stored science data when spacecraft enters the 'safe mode') and autonomously recover from them during NASA's long-life and deep space missions. This would require the development of non-volatile memory. In order to survive in the stringent environment during space exploration missions, onboard memory requirements would also include: (1) survive a high radiation environment (1 Mrad), (2) operate effectively and efficiently for a very long time (10 years), and (3) sustain at least a billion write cycles. Therefore, memory technologies requirements of NASA's Earth Science and Space Science missions are large capacity, non-volatility, high-transfer rate, high radiation resistance, high storage density, and high power efficiency. JPL, under current sponsorship from NASA Space Science and Earth Science Programs, is developing a high-density, nonvolatile and rad-hard Compact Holographic Data Storage (CHDS) system to enable large-capacity, high-speed, low power consumption, and read/write of data in a space environment. The entire read/write operation will be controlled with electrooptic mechanism without any moving parts. This CHDS will consist of laser diodes, photorefractive crystal, spatial light modulator, photodetector array, and I/O electronic interface. In operation, pages of information would be recorded and retrieved with random access and high-speed. The nonvolatile, rad-hard characteristics of the holographic memory will provide a revolutionary memory technology meeting the high radiation challenge facing the Europa Lander mission. Additional information is contained in the original extended abstract.

Chao, T. H.; Reyes, G. F.; Zhou, H.

2001-01-01

278

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

279

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

280

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

281

Unequal a priori probabilities for holographic storage  

NASA Astrophysics Data System (ADS)

Volume holographic memories (VHMs) can deliver high aggregate data rates at a slow page rate by placing on the order of one million pixels per holographic page. By reducing the number of 'on' pixels per VHM data page we may increase the diffracted power into each pixel and therefore increase the number of pages we can store in our memory; although by doing so we have reduced the amount of user information per page. A detailed analysis shows that the information capacity can be increased by 15% with proper adjustment of the binary pixel priors such that a page contains about 25% 'on' pixels. Enumeration block coding techniques allow us to adjust the data priors appropriately with a code rate near the entropy bound for long block lengths. The sparsity of 'on' pixels also helps to reduce the effects of inter-pixel crosstalk by strongly reducing the probability that worst-case pixel patterns (e.g., blocks of 'on' pixels with the center pixel 'off') will occur in the data page. In addition, enumeration coding offers low encoding/decoding latency that scales linearly with the number of pixels per page. In this paper we discuss the theoretical advantage of optimum prior selection, as well as experimental results in achieving this capacity gain. The experiments verify that it is practical to adjust the priors and that an overall capacity gain of around 17% can be achieved for a realistic VHM system.

King, Brian M.; Neifeld, Mark A.

1999-11-01

282

Viscosity and specific volume of bulk metallic glass-forming alloys and their correlation with glass forming ability  

Microsoft Academic Search

The trends in glass formation among bulk metallic glass-forming alloys are investigated within the framework of viscosity and specific volume measurements. This investigation was carried out using four alloys (Zr41.2Ti13.8Cu12.5Ni10Be22.5, Zr57Cu15.4Ni12.6Al10Nb5, Zr52.5Cu17.9Ni14.6Al10Ti5 and Ni59.5Nb40.5) that have widely different glass forming abilities (GFAs). This study shows that the viscosity at the melting temperature is correlated with volume change upon crystallization in

S Mukherjee; J Schroers; Z Zhou; W. L Johnson; W.-K Rhim

2004-01-01

283

Correlation  

Microsoft Academic Search

Examines the use of various methods of correlations, for determining the diagnostic value of tests, used in analysis of abilities, in business psychology, mental development and school records. Also reviews a number of studies done in this regard.

James Burt Miner

1918-01-01

284

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

285

Holographic Information Storage and Retrieval. Final Report.  

ERIC Educational Resources Information Center

A four-month investigation was made of holographic information storage and retrieval. After an extensive review of the state of the art of various holographic systems, it was concluded that digital holographic storage techniques hold the greatest promise for commercial development, especially since they are particularly well suited to computer…

Spencer, J. R.

286

Three-Dimensional TV Using Holographic Stereogram  

Microsoft Academic Search

Computer holographic stereogram (CHS) is useful for holographic 3D TV because it is constructed from the multi camera horizontal viewpoint plane images and is compatible to the multi holographic stereogram image. Each hologram is recorded as a slit hologram (element hologram) but total viewing area and the number of the element holograms have been limited to some extent by the

Koki Sato; Masataka Tozuka; Makoto Ohki; Kunihiko Takano

2010-01-01

287

Correlation between target volume and electron transport effects affecting heterogeneity corrections in stereotactic body radiotherapy for lung cancer.  

PubMed

Recently, stereotactic body radiotherapy (SBRT) for lung cancer is conducted with heterogeneity-corrected treatment plans, as the correction greatly affects the dose delivery to the lung tumor. In this study, the correlation between the planning target volume (PTV) and the dose delivery is investigated by separation of the heterogeneity correction effects into photon attenuation and electron transport. Under Institutional Review Board exemption status, 74 patients with lung cancer who were treated with SBRT were retrospectively evaluated. All treatment plans were generated using an anisotropic analytical algorithm (AAA) of an Eclipse (Varian Medical Systems, Palo Alto, CA) treatment planning system. Two additional plans were created using the same treatment parameters (monitor units, beam angles and energy): a plan with no heterogeneity correction (NC), and a plan calculated with a pencil beam convolution algorithm (PBC). Compared with NC, AAA and PBC isocenter doses were on average 13.4% and 21.8% higher, respectively. The differences in the isocenter dose and the dose coverage for 95% of the PTV (D95%) between PBC and AAA were correlated logarithmically (? = 0.78 and ? = 0.46, respectively) with PTV. Although D95% calculated with AAA was in general 2.9% larger than that for NC, patients with a small PTV showed a negative ?D95% for AAA due to the significant effect of electron transport. The PTV volume shows logarithmic correlation with the effects of the lateral electron transport. These findings indicate that the dosimetric metrics and prescription, especially in clinical trials, should be clearly evaluated in the context of target volume characteristics and with proper heterogeneity correction. PMID:24522269

Akino, Yuichi; Das, Indra J; Cardenes, Higinia R; Desrosiers, Colleen M

2014-07-01

288

Correlations between Moelwyn–Hughes parameter, available volume and intermolecular free-lengths in liquid systems  

Microsoft Academic Search

Thermo-acoustical parameters of liquid mixtures viz., Acetone, Methyl Iodide and Acetone+Methyl Iodide have been evaluated at different temperatures in terms of the coefficient of volume expansion, on the assumption that the Moelwyn–Hughes parameter has been utilized to establish some simple relations between the lattice Gruneisen parameter, Beyer's non-linearity parameter, the Anderson–Gruneisen parameter and the Sharma constant. A relationship among the

R. R. Reddy; K. Rama Gopal; K. Narasimhulu; L. Siva Sankara Reddy; K. Raghavendra Kumar; A. Venkatesulu; C. V. Krishna Reddy

2008-01-01

289

Cerebellar Gray Matter Volume Correlates with Duration of Cocaine Use in Cocaine-Dependent Subjects  

Microsoft Academic Search

This study was conducted to explore differences in gray and white matter volume between cocaine-dependent and healthy comparison subjects using optimized voxel-based morphometry (VBM). Brain magnetic resonance imaging (MRI) and neuropsychological function tests were performed for 40 cocaine-dependent subjects (41.4±6.9 years, 27 men) and 41 healthy age- and sex-matched comparison subjects (38.7±8.8 years, 26 men). Optimally normalized whole brain MR

Minyoung E Sim; In Kyoon Lyoo; Chris C Streeter; Julie Covell; Ofra Sarid-Segal; Domenic A Ciraulo; Minue J Kim; Marc J Kaufman; Deborah A Yurgelun-Todd; Perry F Renshaw

2007-01-01

290

Alternative automatic alignment method for specimen tilt-series images based on back-projected volume data cross-correlations.  

PubMed

We devised a new automatic image alignment method for a specimen tilt series; this method is based on the volume data cross-correlation among 3-D cross-sections reconstructed from different sets of projection images (including a single image) for tilt-series alignment or tilt-axis search purposes. This method requires neither markers nor image feature points traceable through the tilt series, and it was examined through simulations and applied to biological thin sections. The method automatically aligned tilt series centred at the correctly detected tilt axis with a precision sufficient for practical applications. PMID:24815505

Tomonaga, Sachihiko; Baba, Misuzu; Baba, Norio

2014-08-01

291

Measuring fractionation, long-wavelength correlations and local volume fraction 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 large polydispersity up to $\\sim 40\\%$ and a skewed parent size distribution. We introduce a novel coarse-grained Voronoi method which minimises size bias in measuring local volume fraction to identify the phases. Second, a variety of spatial correlation functions are developed which do not require a clear distinction between the phases. These can be applied whether or not a system is phase separated, to determine the presence of 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 $\\textit{direction}$ differing between two interaction potentials which are identical in the monodisperse case. These qualitative features are predicted by a perturbative theory, which only requires a monodisperse reference as input. T...

Williamson, John J

2014-01-01

292

Holographic lithography for biomedical applications  

NASA Astrophysics Data System (ADS)

Fabrication of scaffolds for cell growth with appropriate mechanical characteristics is top-most important for successful creation of tissue. Due to ability of fast fabrication of periodic structures with a different period, the holographic lithography technique is a suitable tool for scaffolds fabrication. The scaffolds fabricated by holographic lithography can be used in various biomedical investigations such as the cellular adhesion, proliferation and viability. These investigations allow selection of the suitable material and geometry of scaffolds which can be used in creation of tissue. Scaffolds fabricated from di-acrylated poly(ethylene glycol) (PEG-DA-258) over a large area by holographic lithography technique are presented in this paper. The PEG-DA scaffolds fabricated by holographic lithography showed good cytocompatibility for rabbit myogenic stem cells. It was observed that adult rabbit muscle-derived myogenic stem cells grew onto PEG-DA scaffolds. They were attached to the pillars and formed cell-cell interactions. It demonstrates that the fabricated structures have potential to be an interconnection channel network for cell-to-cell interactions, flow transport of nutrients and metabolic waste as well as vascular capillary ingrowth. These results are encouraging for further development of holographic lithography by improving its efficiency for microstructuring three-dimensional scaffolds out of biodegradable hydrogels

Stankevicius, E.; Balciunas, E.; Malinauskas, M.; Raciukaitis, G.; Baltriukiene, D.; Bukelskiene, V.

2012-06-01

293

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

294

Correlation  

Microsoft Academic Search

A spirit of conservatism and caution in regard to intelligence test correlations animates numerous papers. Several writers urge the use of units of rank orders, in the estimating of mental abilities. (See, Boring, McEwen, Michael and the Scott Laboratory). Several others like Ruml, Myers, Mitchell, Thorndike and Thompson hold various views in favor of or in criticism against numerous concepts

J. B. Miner

1920-01-01

295

Holographic Photolysis for Multiple Cell Stimulation in Mouse Hippocampal Slices  

PubMed Central

Background Advanced light microscopy offers sensitive and non-invasive means to image neural activity and to control signaling with photolysable molecules and, recently, light-gated channels. These approaches require precise and yet flexible light excitation patterns. For synchronous stimulation of subsets of cells, they also require large excitation areas with millisecond and micrometric resolution. We have recently developed a new method for such optical control using a phase holographic modulation of optical wave-fronts, which minimizes power loss, enables rapid switching between excitation patterns, and allows a true 3D sculpting of the excitation volumes. In previous studies we have used holographic photololysis to control glutamate uncaging on single neuronal cells. Here, we extend the use of holographic photolysis for the excitation of multiple neurons and of glial cells. Methods/Principal Findings The system combines a liquid crystal device for holographic patterned photostimulation, high-resolution optical imaging, the HiLo microscopy, to define the stimulated regions and a conventional Ca2+ imaging system to detect neural activity. By means of electrophysiological recordings and calcium imaging in acute hippocampal slices, we show that the use of excitation patterns precisely tailored to the shape of multiple neuronal somata represents a very efficient way for the simultaneous excitation of a group of neurons. In addition, we demonstrate that fast shaped illumination patterns also induce reliable responses in single glial cells. Conclusions/Significance We show that the main advantage of holographic illumination is that it allows for an efficient excitation of multiple cells with a spatiotemporal resolution unachievable with other existing approaches. Although this paper focuses on the photoactivation of caged molecules, our approach will surely prove very efficient for other probes, such as light-gated channels, genetically encoded photoactivatable proteins, photoactivatable fluorescent proteins, and voltage-sensitive dyes. PMID:20195547

Papagiakoumou, Eirini; Ventalon, Cathie; Angulo, Maria Cecilia; Emiliani, Valentina

2010-01-01

296

A Critical Examination of Relative Concentrations of Volume-correlated and Surface-correlated Submicron Globules of Pure Fe-0 in Lunar Soils  

NASA Technical Reports Server (NTRS)

Impacts on lunar soils produce melt and vapor in an approximate proportion of 7:1. The melt scavenges soil grains of diverse size, quenches and forms agglutinates, thereby converting surface correlated components of soil grains as volume correlated components; simultaneously, parts of the vapor may condense or escape. Cumulative small impacts increase the maturity of the soils, increase the abundance of agglutinates, and increase the concentration of vapor condensated material. Since the discovery of vapor deposited crystalline Fe-0 in vugs of regolith breccias and the theoretical anticipation of amorphous vapor deposits of diverse composition coating lunar soils grains, empirical evidence is gathering in support of such deposits, now commonly called vapor deposited patina (VDP). In addition, submicron globules of Fe-0 are seen to be ubiquitous in VDP. The amorphous VDP lowers the albedo of lunar soils, affects magnetic properties of soils, changes the slopes of uv-vis-ir reflectance spectra, and potentially also alters the gamma and x-ray spectra of lunar soils, compromising compositional inferences from remote sensing.

Basu, A.; McKay, D. S.; Wentworth, S. J.

2003-01-01

297

Holographic wavefront sensor for fast defocus measurement  

NASA Astrophysics Data System (ADS)

Atmospheric effects significantly influence the propagation of light. Conventional adaptive optics systems, based on Shack-Hartmann sensors (SHS), work well for vertical-path propagation. However, for more challenging scenarios like horizontal-path imaging or free-space laser communications through extended-volume turbulence and strong scintillation, the bandwidth of SHS is insufficient. A promising alternative is the holographic wavefront sensor (HWFS). Our paper deals with some dependencies and limitations of the HWFS. First, we show that the sensitivity of the HWFS is highly dependent on the detector size. The smaller the detector, the more sensitive is the sensor. This has consequences in the photon-starved regime, which would naturally occur when the sensor is operated at the intended MHz speed. Second, we show that uncorrected (or residual) tip/tilt has a large impact on the accuracy of the measurement. We present experimental results of measuring an important and also easily correctable aberration, defocus, with the HWFS.

Zepp, Andreas; G?adysz, Szymon; Stein, Karin

2013-12-01

298

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

2009-11-26

299

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

2008-09-20

300

Holographic anatomy of fuzzballs  

E-print Network

We present a comprehensive analysis of 2-charge fuzzball solutions, that is, horizon-free non-singular solutions of IIB supergravity characterized by a curve on R^4. We propose a precise map that relates any given curve to a specific superposition of R ground states of the D1-D5 system. To test this proposal we compute the holographic 1-point functions associated with these solutions, namely the conserved charges and the vacuum expectation values of chiral primary operators of the boundary theory, and find perfect agreement within the approximations used. In particular, all kinematical constraints are satisfied and the proposal is compatible with dynamical constraints although detailed quantitative tests would require going beyond the leading supergravity approximation. We also discuss which geometries may be dual to a given R ground state. We present the general asymptotic form that such solutions must have and present exact solutions which have such asymptotics and therefore pass all kinematical constraints. Dynamical constraints would again require going beyond the leading supergravity approximation.

I. Kanitscheider; K. Skenderis; M. Taylor

2006-11-15

301

Digital holographic display  

NASA Astrophysics Data System (ADS)

This paper describes how a Digital Holographic Projector is designed and implemented to project two-dimension virtual images onto the volumetric display media. In this research, we focus on the method to create 3D models, diffractive algorithm and the display media. A 3D model is generated based on the 360° view with views at every 10° interval from a 3D perspective view software. The hologram interference fringes are re-producing from the Fraunhofer algorithm. In order to make more flexible and portable, a Compact Vision System is introduced to storage multiply interference fringes. At the same time, the fringes are sent out at 30 Hz frame by frame continually to the digital micro-mirror1. With the presence of Nd: YVO4 green laser and various optical components, the 3D 360° hologram images are dynamically reconstructed and projected onto the high speed rotating diffuser forming a 3D model at any viewing angle on the volumetric display media. Both volumetric display media, wet and dry methods are demonstrated to show their feasibility and convenience. Finally, the dry volumetric technique with vertical projection mounting is adopted and as the result shown that the speckle noise is significance reduced.

Lee, Cheok Peng; Chia, Yong Poo; Singh, Vijay Raj; Asundi, A.; Khoo, Xuan Jie; Tay, Kiat Long; Zhou, Junxiang

2010-03-01

302

Digital holographic display  

NASA Astrophysics Data System (ADS)

This paper describes how a Digital Holographic Projector is designed and implemented to project two-dimension virtual images onto the volumetric display media. In this research, we focus on the method to create 3D models, diffractive algorithm and the display media. A 3D model is generated based on the 360° view with views at every 10° interval from a 3D perspective view software. The hologram interference fringes are re-producing from the Fraunhofer algorithm. In order to make more flexible and portable, a Compact Vision System is introduced to storage multiply interference fringes. At the same time, the fringes are sent out at 30 Hz frame by frame continually to the digital micro-mirror1. With the presence of Nd: YVO4 green laser and various optical components, the 3D 360° hologram images are dynamically reconstructed and projected onto the high speed rotating diffuser forming a 3D model at any viewing angle on the volumetric display media. Both volumetric display media, wet and dry methods are demonstrated to show their feasibility and convenience. Finally, the dry volumetric technique with vertical projection mounting is adopted and as the result shown that the speckle noise is significance reduced.

Lee, Cheok Peng; Chia, Yong Poo; Singh, Vijay Raj; Asundi, A.; Khoo, Xuan Jie; Tay, Kiat Long; Zhou, Junxiang

2009-12-01

303

Holographic image archive.  

PubMed

This paper presents an associative technique for content-based retrieval into image archive, based on a computing paradigm called Multidimensional Holographic Associative Computing (MHAC). Unlike any prior Artificial Associative Memory (AAM), MHAC has the unique ability fo focus on any subject of pixels in the sample image and retrieve learned images based on the similarity of the visual objects. In addition, MHAC is adaptive, graciously accommodative of imprecision, efficient, parallelizable, scalable and optically realizable. Together, these excellent properties of MHAC offer a promising novel approach to a content-based search into massive image archives. The paper presents the necessary transformational steps to incorporate this new mechanism into a complete image archival and retrieval system. This is the first associative search approach for content-based retrieval in image repository. The results show that this search system is capable of retrievals by using pattern objects as small as 10-15% of the query image frame at better than 90% accuracy. This demonstrates the potential of MHAC for handing contest-based image applications far beyond the capability of current associative memories. The design, methodology and performance of this system have been illustrated in this paper through its application in managing a Medical Image Archive (MEDIA). PMID:8954232

Khan, J I; Yun, D Y

1996-01-01

304

Scanning holographic lidar telescope  

NASA Technical Reports Server (NTRS)

We have developed a unique telescope for lidar using a holographic optical element (HOE) as the primary optic. The HOE diffracts 532 nm laser backscatter making a 43 deg angle with a normal to its surface to a focus located 130 cm along the normal. The field of view scans a circle as the HOE rotates about the normal. The detector assembly and baffling remain stationary, compared to conventional scanning lidars in which the entire telescope and detector assembly require steering, or which use a large flat steerable mirror in front of the telescope to do the pointing. The spectral bandpass of our HOE is 50 nm (FWHM). Light within that bandpass is spectrally dispersed at 0.6 nm/mm in the focal plane. An aperture stop reduces the bandpass of light reaching the detector from one direction to 1 nm while simultaneously reducing the field of view to 1 mrad. Wavelengths outside the 50 nm spectral bandpass pass undiffracted through HOE to be absorbed by a black backing. Thus, the HOE combines three functions into one optic: the scanning mirror, the focusing mirror, and a narrowband filter.

Schwemmer, Geary K.; Wilkerson, Thomas D.

1993-01-01

305

Synaptic vesicle exocytosis in hippocampal synaptosomes correlates directly with total mitochondrial volume.  

PubMed

Synaptic plasticity in many regions of the central nervous system leads to the continuous adjustment of synaptic strength, which is essential for learning and memory. In this study, we show by visualizing synaptic vesicle release in mouse hippocampal synaptosomes that presynaptic mitochondria and, specifically, their capacities for ATP production are essential determinants of synaptic vesicle exocytosis and its magnitude. Total internal reflection microscopy of FM1-43 loaded hippocampal synaptosomes showed that inhibition of mitochondrial oxidative phosphorylation reduces evoked synaptic release. This reduction was accompanied by a substantial drop in synaptosomal ATP levels. However, cytosolic calcium influx was not affected. Structural characterization of stimulated hippocampal synaptosomes revealed that higher total presynaptic mitochondrial volumes were consistently associated with higher levels of exocytosis. Thus, synaptic vesicle release is linked to the presynaptic ability to regenerate ATP, which itself is a utility of mitochondrial density and activity. PMID:22772899

Ivannikov, Maxim V; Sugimori, Mutsuyuki; Llinás, Rodolfo R

2013-01-01

306

Invisible engineering of holographic illusion  

NASA Astrophysics Data System (ADS)

Recent developments in production techniques of pulsed holograms and holographic stereograms have ameliorated to provide high quality three dimensional illusions that echo the apparently innate need of society to replicate itself through artificial means. A commercial platform has been found for these archetypical illusions through the mass production and distribution of embossed stereograms that depict popular celebrities from the music industry. As pulse recordings of the rich and famous become better known, and as former presidents queue to join the holographic hall of fame, the author asks `is it documentation or entertainment that is shaping the future of holography?'

Richardson, Martin J.

1993-03-01

307

Optimal complex field holographic projection.  

PubMed

We describe a technique that uses complex field holograms to project three-dimensional light patterns. Holographic projection commonly uses phase-only encoding since accurately representing complex holograms using both amplitude and phase spatial light modulators reduces the optical throughput significantly. Here, we use a lossless projection via the generalized phase contrast method to produce the necessary amplitude pattern required for complex field holographic projection. We numerically evaluate the technique and demonstrate high optical throughput with reduced undesired high diffraction orders. PMID:21847164

Go, Mary Ann; Ng, Ping-Fung; Bachor, Hans A; Daria, Vincent Ricardo

2011-08-15

308

Hadron physics in holographic QCD  

NASA Astrophysics Data System (ADS)

Hadron physics deals with the study of strongly interacting subatomic particles such as neutrons, protons, pions and others, collectively known as baryons and mesons. Physics of strong interaction is difficult. There are several approaches to understand it. However, in the recent years, an approach called, holographic QCD, based on string theory (or gauge-gravity duality) is becoming popular providing an alternative description of strong interaction physics. In this article, we aim to discuss development of strong interaction physics through QCD and string theory, leading to holographic QCD.

Santra, A. B.; Lombardo, U.; Bonanno, A.

2012-07-01

309

Holographic grating formation in photopolymers  

NASA Astrophysics Data System (ADS)

We introduce a model describing real-time grating formation in holographic photopolymers, assuming that the diffusion of free monomers is much faster than the grating formation. This model, which combines polymerization kinetics with results from coupled-wave theory, indicates that the grating formation time depends sublinearly on the average holographic recording intensity and the beam intensity ratio controls the grating index modulation at saturation. We validate the model by comparing its predictions with the results of experiments in which DuPont HRF-150X001 photopolymer was used.

Piazzolla, Sabino; Jenkins, B. Keith

1996-07-01

310

Coherence-controlled holographic microscope.  

PubMed

Transmitted-light coherence-controlled holographic microscope (CCHM) based on an off-axis achromatic interferometer allows us to use light sources of arbitrary degree of temporal and spatial coherence. Besides the conventional DHM modes such as quantitative phase contrast imaging and numerical 3D holographic reconstruction it provides high quality (speckle-free) imaging, improved lateral resolution and optical sectioning by coherence gating. Optical setup parameters and their limits for a technical realization are derived and described in detail. To demonstrate the optical sectioning property of the microscope a model sample uncovered and then covered with a diffuser was observed using a low-coherence light source. PMID:20941100

Kolman, Pavel; Chmelík, Radim

2010-10-11

311

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

312

Holographic DC conductivities from the open string metric  

E-print Network

We study the DC conductivities of various holographic models using the open string metric (OSM), which is an effective metric geometrizing density and electromagnetic field effect. We propose a new way to compute the nonlinear conductivity using OSM. As far as the final conductivity formula is concerned, it is equivalent to the Karch-O'Bannon's real-action method. However, it yields a geometrical insight and technical simplifications. Especially, a real-action condition is interpreted as a regular geometry condition of OSM. As applications of the OSM method, we study several holographic models on the quantum Hall effect and strange metal. By comparing a Lifshitz background and the Light-Cone AdS, we show how an extra parameter can change the temperature scaling behavior of conductivity. Finally we discuss how OSM can be used to study other transport coefficients, such as diffusion constant, and effective temperature induced by the effective world volume horizon.

Keun-Young Kim; Da-Wei Pang

2011-08-18

313

Dynamic holographic imaging of the beating human heart  

PubMed

Background--Currently, the reporting and archiving of echocardiographic data suffer from the difficulty of representing heart motion on printable 2-dimensional (2D) media. Methods and Results--We studied the capability of holography to integrate motion into 2D echocardiographic prints. Images of normal human hearts and of a variety of mitral valve function abnormalities (mitral valve prolapse, systolic anterior motion of the mitral leaflets, and obstruction of the mitral valve by a myxoma) were acquired digitally on standard echocardiographic machines. Images were processed into a data format suitable for holographic printing. Angularly multiplexed holograms were then printed on a prototype holographic "laser" printer, with integration of time in vertical parallax, so that heart motion became visible when the hologram was tilted up and down. The resulting holograms displayed the anatomy with the same resolution as the original acquisition and allowed detailed study of valve motion with side-by-side comparison of normal and abnormal findings. Comparison of standard echocardiographic measurements in original echo frames and corresponding hologram views showed an excellent correlation of both methods (P<0.0001, r2=0.979, mean bias=2.76 mm). In this feasibility study, both 2D and 3D holographic images were produced. The equipment needed to view these holograms consists of only a simple point-light source. Conclusions--Holographic representation of myocardial and valve motion from echocardiographic data is feasible and allows the printing on a 2D medium of the complete heart cycle. Combined with the recent development of online holographic printing, this novel technique has the potential to improve reporting, visualization, and archiving of echocardiographic imaging. PMID:9950651

Hunziker; Smith; Scherrer-Crosbie; Liel-Cohen; Levine; Nesbitt; Benton; Picard

1999-02-01

314

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

315

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

316

Holographic disk for data storage  

Microsoft Academic Search

Prospects of development of a holographic system for recording and reproduction of digital signals are considered and basic principles of the design of these systems are discussed. Devices for recording and reproduction are described and some results of experimental investigations of these devices are reported. Possible applications are identified on the basis of the parameters already achieved.

A L Mikaélyan; Anatolii F Vanin; É Kh Gulanyan; S A Prokopenko

1987-01-01

317

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

318

Large holographically corrected space telescopes  

Microsoft Academic Search

The next generation optical space telescopes with apertures > 10 m for imaging, lidar, communications and directed energy focusing will be unable to use conventional technologies which are impractical or too costly. Our solution is to construct a telescope from a lightweight, low-quality primary, which is holographically corrected for surface distortions, in situ. This scheme makes it possible to correct

Geoff Andersen; W. R. White; Randall J. Knize

1998-01-01

319

Integraf - Holographic Film and Supplies  

NSDL National Science Digital Library

Integraf is an international supplier of holographic film and materials. The instructional web site has a detailed index of links to other web sites with information on how to make holograms. You can also learn how to make holograms on-line.

Integraf

2003-10-10

320

Holographic system for nondestructive testing  

Microsoft Academic Search

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

R. L. Kurtz

1975-01-01

321

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

322

Serum YKL-40 Levels Correlate with Infarct Volume, Stroke Severity, and Functional Outcome in Acute Ischemic Stroke Patients  

PubMed Central

Background and Purpose YKL-40 is associated with various neurological disorders. However, circulatory YKL-40 levels early after onset of acute ischemic stroke (AIS) have not been systematically assessed. We aimed to identify the temporal changes and clinical usefulness of measuring serum YKL-40 immediately following AIS. Methods Serum YKL-40 and C-reactive protein (CRP) levels were monitored over time in AIS patients (n?=?105) and compared with those of stroke-free controls (n?=?34). Infarct volume and stroke severity (National Institutes of Health Stroke Scale; NIHSS) were measured within 48 hours of symptom onset, and functional outcome (modified Rankin Scale; mRS) was measured 3 months after AIS. Results Within 12 hours of symptom onset, levels of YKL-40 (251 vs. 41 ng/mL) and CRP (1.50 vs. 0.96 µg/mL) were elevated in AIS patients compared to controls. The power of YKL-40 for discriminating AIS patients from controls was superior to that of CRP (area under the curve 0.84 vs. 0.64) and YKL-40 (r?=?0.26, P<0.001) but not CRP levels were correlated with mRS. On day 2 of admission (D2), YKL-40 levels correlated with infarct volume and NIHSS. High YKL-40 levels predicted poor functional outcome (odds ratio 5.73, P?=?0.03). YKL-40 levels peaked on D2 and declined on D3, whereas CRP levels were highest on D3. Conclusions Our results demonstrate serial changes in serum YKL-40 levels immediately following AIS and provide the first evidence that it is a valid indicator of AIS extent and an early predictor of functional outcome. PMID:23272150

Park, Hyun Young; Jun, Chang-Duk; Jeon, Se-Jeong; Choi, See-Sung; Kim, Hak-Ryul; Choi, Dan-Bee; Kwak, Seongae; Lee, Hak-Seung; Cheong, Jin Sung; So, Hong-Seob; Lee, Young-Jin; Park, Do-Sim

2012-01-01

323

Post-traumatic stress symptoms correlate with smaller subgenual cingulate, caudate, and insula volumes in unmedicated combat veterans  

PubMed Central

Prior studies have examined differences in brain volume between PTSD and control subjects. Convergent findings include smaller hippocampus and medial prefrontal cortex volumes in PTSD. However, post-traumatic stress symptoms (PTSS) exist on a spectrum, and neural changes may occur beyond the diagnostic threshold of PTSD. We examined the relationship between PTSS and gray matter among combat-exposed U.S. military veterans. Structural brain MRI was obtained on 28 combat veterans from Operations Enduring and Iraqi Freedom. PTSS were assessed using the Clinician-Administered PTSD Scale (CAPS). Thirteen subjects met criteria for PTSD. Subjects were unmedicated, and free of major comorbid psychiatric disorders. Images were analyzed using voxel-based morphometry, and regressed against the total CAPS score and trauma load. Images were subsequently analyzed by diagnosis of PTSD vs. non-PTSD. CAPS scores were inversely correlated with subgenual cingulate (sgACC), caudate, hypothalamus, insula, and left middle temporal gyrus (MTG). Group contrast revealed smaller sgACC, caudate, hypothalamus, left insula, left MTG, and right MFG in the PTSD group. PTSS are associated with abnormalities in limbic structures that may underlie the pathophysiology of PTSD. These abnormalities exist on a continuum with PTSS, beyond a diagnosis of PTSD. PMID:23021615

Herringa, Ryan; Phillips, Mary; Almeida, Jorge; Insana, Salvatore; Germain, Anne

2012-01-01

324

Holographic characteristics of citrate ion modified gold nano-particles dispersed photopolymer  

NASA Astrophysics Data System (ADS)

Hydrophilic photopolymers with AA as the monomer are versatile materials for use as holographic recording media. It has demonstrated a possibility to improve the refractive index modulation by doping inorganic nanoparticles into the polymer matrix. But the agglomerate effect of inorganic nanoparticles always deteriorate the holographic storage characteristics of the inorganic nanoparticle dispersed photopolymer compound materials. monodisperse hydrophilic gold nanoparticles are fabricated by the method of sodium citrate reduction, and then were dispersed into the PVA/AA photopolymer. Our results indicate that citrate ions coated on the surface of gold nanoparticles can effectively prevent the agglomerate effect, so that the gold nanoparticles can uniformly dispersed in the sol-gel photopolymer. The permanent refractive index grating can be formed owing to a spatial distribution of the effective refractive index with periodically distributed nanoparticles and polymerized monomers during the holographic recording. Furthermore, the citrate ion modified gold nanoparticles and polymer chain can induce the formation of hydrogen bonds which can prevent the material from distortion and at the same time improve the stability of the material by the coordination effect of carboxylate. Therefore, the incorporation of gold nanoparticles leads to a significantly improvement in the holographic properties of the materials, so that the volume shrinkage during the holographic exposure can be well suppressed. Additionally, there exists the optimum concentration of gold nanoparticles, at which the maximum diffraction efficiency can be as high as 90% and the volume shrinkage can be reduced to 0.8%.

Xue, Xiao-yu; Hai, Fu-Sheng; Gao, Li-Zhen; He, Fei; Li, Chun-Liu; Li, Yun-Xi; Huang, Ming-Ju

325

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

326

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

2014-07-24

327

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

PubMed

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. PMID:25362335

Williamson, J J; Evans, R M L

2014-10-28

328

April 1, 2000 / Vol. 25, No. 7 / OPTICS LETTERS 499 Multiplexed phase-conjugate holographic  

E-print Network

reference angle or wavelength the system would have to wait while the PCM reflectivity built up, decreasing holographic storage system in which a phase-conjugate object beam is reconstructed by the same reference beam into the desired volume hologram for long-term storage. This method combines the immunity to lens aberrations

Rey Juan Carlos, Universidad

329

Experimental investigation of a page-oriented Lippmann holographic data storage system  

E-print Network

Polytechnique, RD 128, 91127 Palaiseau cedex, France ABSTRACT Lippmann photography is a more than one century feature some hints to apply this technique to high density data storage by wavelength multiplexing holography. Keywords: Optical data storage, holographic and volume memories, Lippmann photography 1

Boyer, Edmond

330

High power CW Tm:YLF laser with a holographic output Alex Dergachev, Peter F. Moulton  

E-print Network

High power CW Tm:YLF laser with a holographic output coupler Alex Dergachev, Peter F. Moulton Q, 32816 E-mail: lbglebov@creol.ucf.edu Abstract: We report a diode-pumped, CW Tm:YLF laser, with a volume position for operation as a resonant reflector in the resonator of a CW Tm:YLF laser. From the experiments

Glebov, Leon

331

Holographic interaction effects on transport in Dirac semimetals  

E-print Network

Strongly interacting Dirac semimetals are investigated using a holographic model especially geared to compute the single-particle correlation function for this case, including both interaction effects and nonzero temperature. We calculate the (homogeneous) electrical conductivity at zero chemical potential, and show that it consists of two contributions. The interband contribution scales as a power law either in frequency or in temperature for low frequency. The precise power is related to a critical exponent of the dual holographic theory, which is a parameter in the model. On top of that we find for nonzero temperatures a Drude peak corresponding to intraband transitions. A behavior similar to Coulomb interactions is recovered as a special limiting case.

V. P. J. Jacobs; S. J. G. Vandoren; H. T. C. Stoof

2014-03-14

332

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

333

Anatomy of new SUSY breaking holographic RG flows  

E-print Network

We find and thoroughly study new supergravity domain wall solutions which are holographic realizations of supersymmetry breaking strongly coupled gauge theories. We set ourselves in an N=2 gauged supergravity with a minimal content in order to reproduce a dual N=1 effective SCFT which has a U(1)_R symmetry, a chiral operator whose components are responsible for triggering the RG flow, and an additional U(1)_F symmetry. We present a full three dimensional parameter space of solutions, which generically break supersymmetry. Some known solutions are recovered for specific sets of values of the parameters, with the new solutions interpolating between them. The generic backgrounds being singular, we provide a stability test of their dual theories by showing that there are no tachyonic resonances in the two point correlators. We compute the latter by holographic renormalization. We also carefully analyze the appearance of massless modes, such as the dilaton and the R axion, when the respective symmetries are sponta...

Argurio, Riccardo; Redigolo, Diego

2014-01-01

334

Label-free cytotoxicity screening assay by digital holographic microscopy.  

PubMed

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; Turcatti, Gerardo

2013-03-01

335

Cerebral Blood Volume Calculated by Dynamic Susceptibility Contrast-Enhanced Perfusion MR Imaging: Preliminary Correlation Study with Glioblastoma Genetic Profiles  

PubMed Central

Purpose To evaluate the usefulness of dynamic susceptibility contrast (DSC) enhanced perfusion MR imaging in predicting major genetic alterations in glioblastomas. Materials and Methods Twenty-five patients (M:F?=?13?12, mean age: 52.1±15.2 years) with pathologically proven glioblastoma who underwent DSC MR imaging before surgery were included. On DSC MR imaging, the normalized relative tumor blood volume (nTBV) of the enhancing solid portion of each tumor was calculated by using dedicated software (Nordic TumorEX, NordicNeuroLab, Bergen, Norway) that enabled semi-automatic segmentation for each tumor. Five major glioblastoma genetic alterations (epidermal growth factor receptor (EGFR), phosphatase and tensin homologue (PTEN), Ki-67, O6-methylguanine-DNA methyltransferase (MGMT) and p53) were confirmed by immunohistochemistry and analyzed for correlation with the nTBV of each tumor. Statistical analysis was performed using the unpaired Student t test, ROC (receiver operating characteristic) curve analysis and Pearson correlation analysis. Results The nTBVs of the MGMT methylation-negative group (mean 9.5±7.5) were significantly higher than those of the MGMT methylation-positive group (mean 5.4±1.8) (p?=?.046). In the analysis of EGFR expression-positive group, the nTBVs of the subgroup with loss of PTEN gene expression (mean: 10.3±8.1) were also significantly higher than those of the subgroup without loss of PTEN gene expression (mean: 5.6±2.3) (p?=?.046). Ki-67 labeling index indicated significant positive correlation with the nTBV of the tumor (p?=?.01). Conclusion We found that glioblastomas with aggressive genetic alterations tended to have a high nTBV in the present study. Thus, we believe that DSC-enhanced perfusion MR imaging could be helpful in predicting genetic alterations that are crucial in predicting the prognosis of and selecting tailored treatment for glioblastoma patients. PMID:23977117

Ryoo, Inseon; Choi, Seung Hong; Kim, Ji-Hoon; Sohn, Chul-Ho; Kim, Soo Chin; Shin, Hwa Seon; Yeom, Jeong A.; Jung, Seung Chai; Lee, A. Leum; Yun, Tae Jin; Park, Chul-Kee; Park, Sung-Hye

2013-01-01

336

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

337

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

PubMed

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 (R (2)) 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

338

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

339

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

340

Investigation of uses of holographic optical elements  

NASA Technical Reports Server (NTRS)

The data represent a thorough study of the aberrations and imaging properties of holographic optical elements. Principle studies include (1) the indepth experimental investigation of single holographic optical elements, (2) the verification of the accuracy of the theoretical computer-based description of hologram behavior, (3) the computer-generation of interferograms that are characteristic of a prescribed aberrated imaging condition, (4) the experimental verification of wavelength optimization, (5) the experimental determination of the space bandwidth product of single holographic optical elements as a function of bending and field angle, and (6) the first experimental study of the aberration properties of holographic optical elements constructed in very thick (750 microns) recording media.

Zech, R. G.; Latta, J. N.

1973-01-01

341

Instability of holographic dark energy models  

E-print Network

We investigate the difference between holographic dark energy, Chaplygin gas, and tachyon model with constant potential. For this purpose, we examine their squared speeds of sound which are evaluated to zeroth order in perturbation theory and hence depends only on time. We find that the squared speed for holographic dark energy is always negative when choosing the future event horizon as the IR cutoff, while those for Chaplygin gas and tachyon are non-negative. This means that the perfect fluid for holographic dark energy is classically unstable. Hence the holographic interpretation for Chaplygin gas and tachyon is problematic.

Yun Soo Myung

2007-06-26

342

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

343

Correlation between Volume Fraction of Silicon Clusters in Amorphous Silicon Films and Optical Emission Properties of Si* and SiH*  

NASA Astrophysics Data System (ADS)

The volume fraction of silicon clusters in amorphous silicon (a-Si:H) films has been investigated using specially designed quartz crystal microbalances (QCMs) together with optical emission spectroscopy (OES). The optical emission intensities of Si* and SiH* and their intensity ratios are selected for comparison with the QCM results. We show that the volume fraction of silicon clusters strongly correlates with not only the electron temperature but also the SiH* intensity. This suggests that the ratios of Si*/SiH* and SiH* can be used to predict the volume fraction of Si clusters in a-Si:H films.

Kim, Yeonwon; Hatozaki, Kosuke; Hashimoto, Yuji; Uchida, Giichiro; Kamataki, Kunihiro; Itagaki, Naho; Seo, Hyunwoong; Koga, Kazunori; Shiratani, Masaharu

2013-11-01

344

Influence of fabrication conditions on characteristics of phenanthrenequinone-doped poly(methyl methacrylate) photopolymer for holographic memory  

NASA Astrophysics Data System (ADS)

In this paper, we experimentally investigate the influence of the fabrication conditions on holographic characteristics in phenanthrenequinone-doped poly(methyl methacrylate) (PQ:PMMA) bulk photopolymer. In our investigation, the PQ:PMMA bulk samples are fabricated by use of a two-step thermo-polymerization method. We firstly propose to monitor relative viscosity of the monomer solution during the sample preparation to obtain a reliable criterion for material fabrication. We then compare experimentally characteristics of 2-mm thick samples fabricated with different conditions for holographic memory. The results show that the conditions in the first step play a important rule for fabricating bulk PQ:PMMA samples with good optical uniformity. In addition, the conditions in the second step play the rule for controlling the concentration of residual monomer and determine holographic characteristics. These results can provide a useful rule for fabricating bulk PQ:PMMA photopolymers for further applications on volume holographic data storage.

Lin, Shiuan Huei; Cho, Sheng-Lung; Lin, June-Hua; Hsu, Ken Y.; Chi, Sien

2014-06-01

345

Characterization of an acrylamide-based photopolymer for data storage utilizing holographic angular multiplexing  

NASA Astrophysics Data System (ADS)

An acrylamide-based photopolymer formulated in the Centre for Industrial and Engineering Optics has been investigated with a view to further optimization for holographic data storage. Series of 18-30 gratings were angularly multiplexed in a volume of photopolymer layer at a spatial frequency of 1500 lines mm-1. Since the photopolymer is a saturable material, an exposure scheduling method was used to exploit the entire dynamic range of the material and allow equal strength holographic gratings to be recorded. This investigation yielded the photopolymer M/# for moderately thin layers. Photopolymer temporal stability was also studied by measuring variations of material shrinkage, Bragg selectivity curve, and diffraction efficiency.

Sherif, Hosam; Naydenova, Izabela; Martin, Suzanne; McGinn, Colm; Toal, Vincent

2005-05-01

346

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

347

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

2010-10-26

348

Holographic multiverse and conformal invariance  

NASA Astrophysics Data System (ADS)

We consider a holographic description of the inflationary multiverse, according to which the wave function of the universe is interpreted as the generating functional for a lower dimensional Euclidean theory. We analyze a simple model where transitions between inflationary vacua occur through bubble nucleation, and the inflating part of spacetime consists of de Sitter regions separated by thin bubble walls. In this model, we present some evidence that the dual theory is conformally invariant in the UV.

Garriga, Jaume; Vilenkin, Alexander

2009-11-01

349

Sound modes in holographic superfluids  

SciTech Connect

Superfluids support many different types of sound waves. We investigate the relation between the sound waves in a relativistic and a nonrelativistic 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 nonrelativistic, incompressible case.

Herzog, Christopher P.; Yarom, Amos [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)

2009-11-15

350

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

351

Optical Conductivity with Holographic Lattices  

E-print Network

We add a gravitational background lattice to the simplest holographic model of matter at finite density and calculate the optical conductivity. With the lattice, the zero frequency delta function found in previous calculations (resulting from translation invariance) is broadened and the DC conductivity is finite. The optical conductivity exhibits a Drude peak with a cross-over to power-law behavior at higher frequencies. Surprisingly, these results bear a strong resemblance to the properties of some of the cuprates.

Gary T. Horowitz; Jorge E. Santos; David Tong

2012-04-02

352

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

353

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

354

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

355

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

356

Highly effective dynamic holographic gratings in doped bismuth titanate crystals and applications to metrology  

NASA Astrophysics Data System (ADS)

Highly efficient volume reflective, dynamical holographic gratings in doped Ti12TiO20 crystals have been observed. We demonstrated doped Ti12TiO20 single, electro-optical crystal and experimental set up, which combines high reversibility, small response time, high diffraction efficiency and practically unlimited number of cycles hologram recording, readout and erasing. It allows using doped Ti12TiO20 crystal as an attractive diffractive optical element in Dynamical Holographic Sensor -DHS for metrology applications. The high image contrast of the real time dynamical holographic interferograms without application of external electric field has been obtained for non transparent diffuse reflective objects using commercial available CW He-Ne laser. DHS applications for nondestructive test of the most vital parts engineering constructions to prevent premature failure have has been demonstrated. DHS application for visualization of cryogenic fields in the near zone of cryoultrasonic cancer tissue destructor has been presented.

Dovgalenko, George E.; Wu, Ying

2009-05-01

357

Correlation of intracystic pressure with cyst volume, length of common channel, biochemical changes in bile and histopathological changes in liver in choledochal cyst  

PubMed Central

Aims: This study was undertaken to establish correlation between intracholedochal cystic pressure (ICCP) with biochemical changes in bile, liver histology, cyst wall histology, length of common channel, and cyst volume. Materials and Methods: In this cross-sectional study, ICCP was measured after surgical access before any mobilization by direct cyst cannulation. Bile was then aspirated for biochemical estimation (bilirubin, amylase, lipase, pH, and electrolytes). Common channel length and cyst volume were determined by preoperative magnetic resonance cholangiopancreatography (MRCP). Liver histology was assessed under parenchymal, bile duct, and portal parameters. Cyst wall was examined for ulceration, inflammation, fibrosis, and metaplasia. Results: ICCP was recorded in 31 patients; mean and median ICCP were 15.64 and 14 mmHg, respectively (range = 6-30 mmHg). Cases with median ICCP < 14 had median cyst volume of 48 cc (range = 36-115) and amylase 2052 IU/L (range = 190-5052) whereas those with ICCP ? 15 had volume of 20 cc (range = 10-100) (P = 0.004) and amylase 36 IU/L (range = 0-2806) (P = 0.0004) suggesting inverse correlation. No significant correlation was found with bilirubin and electrolytes. ICCP directly correlated with parenchymal changes like hepatocellular damage (P = 0.002) and cholestasis (P = 0.001). It also correlated with bile duct changes. ICCP inversely correlated with cyst wall changes (P = 0.003, 0.0001, 0.023, 0.0013, respectively). High pressure cysts had normal pancreaticobiliary junction. Conclusion: High-pressure cysts tend to be smaller but have more severe backpressure changes in liver parenchyma. Low-pressure cysts have high volume and higher levels of amylase and lipase and therefore have more severe cyst wall changes. PMID:24604978

Sharma, Nitin; Bhatnagar, Veereshwar; Srinivas, M.; Agarwala, Sandeep; Singh, Manoj Kumar; Sharma, Raju

2014-01-01

358

Photoinduced electrokinetic redistribution of nano/microparticles during holographic grating recording in the ferroelectric crystal  

NASA Astrophysics Data System (ADS)

We have investigated photoinduced redistribution of metal nanoparticles, placed on the surface of the ferroelectric photorefractive crystal during recording of dynamic holograms. Motivations for this study were improvement of sensitivity for recording of dynamic holographic gratings, for application in nondestructive testing of materials. The home- made biosynthesized gold and silver colloidal solutions were spread as a thin layer on the ferroelectric photorefractive crystal surface. Holographic gratings were recorded in photorefractive crystal of Fe:LiNbO3(Fe:LN) by the HeNe laser (?=633nm) to avoid direct influence of laser light on nanoparticles. Photorefractive holographic grating initially recorded in the crystal volume produce spatially modulated electric field on the crystal surface. This field led to electrophoretic redistribution of the nanoparicles on the crystal surface that result also in additional contribution to the electric field pattern and also change diffraction efficiency of hologram. In addition, we have recorded holographic grating in Fe:LN placed in 5mm cuvette with silver nanoparticles nanofluid and observed nanoparticles distribution along grating line. We have calculated electrophoretic (EP) and dielectrophoretic (DEP) forces on the crystal surface with holographic photorefractive grating, recorded in the crystal. It is shown that longitudinal (along the crystal surface) components of the DEP-force can be described only with high-contrast approach.

Kukhtarev, N.; Kukhtareva, T.; Wang, J.

2011-10-01

359

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

360

Holographic optical elements as scanning lidar telescopes  

Microsoft Academic Search

We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. Rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed transmission and reflection HOEs for use at the first three harmonic wavelengths of

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

2006-01-01

361

Instability of holographic dark energy models  

Microsoft Academic Search

We investigate the difference between holographic dark energy, Chaplygin gas, and tachyon model with constant potential. For this purpose, we examine their squared speeds of sound which are evaluated to zeroth order in perturbation theory and hence depends only on time. We find that the squared speed for holographic dark energy is always negative when choosing the future event horizon

Yun Soo Myung; Hyung Won Lee

2007-01-01

362

Interacting Holographic Tachyon Model of Dark Energy  

Microsoft Academic Search

We propose a holographic tachyon model of dark energy with interaction between the components of the dark sector. The correspondence between the tachyon field and the holographic dark energy densities allows the reconstruction of the potential and the dynamics of the tachyon scalar field in a flat Friedmann-Robertson-Walker universe. We show that this model can describe the observed accelerated expansion

Alberto Rozas-Fernández; David Brizuela; Norman Cruz

2010-01-01

363

Electron beam generated holographic optical element research  

Microsoft Academic Search

This report describes progress of the e-beam generated holographic optical element research program during 1981. We investigated partitioned computer generated holographic masks for optical matrix-vector multiplication. These masks are partitioned into separate areas for each channel, with each of these areas containing a linear grating to diffract light to its designated detector. A single lens completes the optical system. The

S. M. Arnold

1982-01-01

364

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

365

Real time calculation for holographic video display  

Microsoft Academic Search

For practical holographic video system, it is important to generated holographic fringe as fast as possible. We have proposed an approximation method that can calculate the hologram faster. However, for the full parallax Fresnel hologram, the speed is not enough for real-time calculation. In this paper, we change the type of hologram from Fresnel to image. Since the object points

Takeshi Yamaguchi; Hiroshi Yoshikawa

2006-01-01

366

Fast hologram calculation for holographic video display  

Microsoft Academic Search

For practical holographic video system, it is important to generated holographic fringe as fast as possible. We have proposed an approximation method that can calculate the Fresnel hologram fast. With the proposed method, a hologram with more than one million pixels can be calculated less than one second with a personal computer. To compute the hologram, an object is assumed

Hiroshi Yoshikawa; Takeshi Yamaguchi

2006-01-01

367

The holographic screen at low temperatures  

E-print Network

A permissible spectrum of transverse vibrations for the holographic screen modifies both a distribution of thermal energy over bits at low temperatures and the law of gravitation at small accelerations of free fall in agreement with observations of flat rotation curves in spiral galaxies. This modification relates holographic screen parameters in de Sitter space-time with the Milgrom acceleration in MOND.

V. V. Kiselev; S. A. Timofeev

2010-09-07

368

Holographic techniques for nondestructive testing of tires  

Microsoft Academic Search

Holographic interferometric techniques were used to evaluate the feasibility of the technique in the nondestructive testing (NDT) of commercial automobile tires. Passenger tires with built-in defects were holographically inspected to determine the types of tire defects that can be detected using this method. Separations and voids were located reliably. Defects other than separations and voids were detected in some cases.

H. L. Ceccon

1972-01-01

369

Thermal waves visualized by holographic interferometry.  

PubMed

The propagation of long thermal waves induced in thin aluminum plates by a slowly modulated heat source was investigated by stroboscopic holographic interferometry. The effect of different modulation frequencies on the visualization of such waves is shown. Experimental results confirm analytical thermoelastic predictions. The application of long thermal waves to holographic nondestructive testing is demonstrated. PMID:20489963

Kaufmann, G H; Vest, C M

1987-07-15

370

Disordered holographic systems: Marginal relevance of imperfection  

NASA Astrophysics Data System (ADS)

We continue our study of quenched disorder in holographic systems, focusing on the effects of mild electric disorder. By studying the renormalization group evolution of the disorder distribution at subleading order in perturbations away from the clean fixed point, we show that electric disorder is marginally relevant in (2+1)-dimensional holographic conformal field theories.

Adams, Allan; Yaida, Sho

2014-08-01

371

Holographic memory based on computer generated Fourier-holograms  

NASA Astrophysics Data System (ADS)

Classic holographic memory systems use two-beam approach based on fixation of interference pattern between object and reference coherent beams on holographic recording medium. The size of single pattern is about several micrometers. High precision optical set up is required to form such a microhologram, that is the reason of excessive price for holographic recording devices. Methods of computer holographic synthesis allow to calculate holographic patterns numerically as 2D images. These images can be realized with the use of spatial light modulator, then reduced in optical projection system and exposed on holographic medium. In this paper we represent the research of holographic memory system based on computer generated Fourier holograms projection.

Odinokov, Sergey; Bobrinev, Vladimir; Verenikina, Nina; Zherdev, Alexander; Lushnikov, Dmitriy; Markin, Vladimir; Betin, Aleksander; Zlokazov, Evgeny; Starikov, Rostislav; Evtikhiev, Nikolay; Starikov, Sergey

2013-05-01

372

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

373

Iodine status and its correlations with age, blood pressure, and thyroid volume in South Indian women above 35 years of age (Amrita Thyroid Survey)  

PubMed Central

Background: Thyroid disorders are more commonly seen among females and the prevalence increases with age. There is no population data from India focusing on iodine levels and their correlations with thyroid volume and other factors in adult women. Aim: This study was designed to establish the iodine status and its relation with various factors including thyroid volume measured by ultrasound among the females of Kerala. Materials and Methods: This was a cross sectional house to house survey among the females above 35 years of age in a randomly selected urban area in Cochin Corporation, Kerala State, India. Selected subjects were interviewed, examined and blood and urine tests were done. Thyroid volume was calculated using ultrasound. Results: Among the 508 subjects who participated in the checkup, 471 subjects were included for analysis. Mean age was 50.3 + 10.7 years and 53.2% were postmenopausal. A total of 98% of the subjects were using iodized salt and median urinary iodine excretion (UIE) was 162.6 mcg/l. UIE had negative correlation with age and systolic blood pressure (BP), but had no correlation with thyroid volume (TV), thyroid nodularity, free thyroxine 4 (FT4), thyroid stimulating hormone (TSH) or anti thyroid peroxidase (TPO) levels. Iodine deficiency was more commonly seen in subjects with hypertension and also among postmenopausal females. Conclusions: This study showed that females > 35 years were iodine sufficient, though one third of the subjects had UIE levels less than the recommended level. Iodine levels had significant negative correlation with age and systolic BP and no correlation with thyroid volume or biochemical parameters. Iodine deficiency was significantly higher in subjects with new and known hypertension and this relation merits further evaluation. PMID:22029002

Menon, Vadayath Usha; Chellan, Gopi; Sundaram, Karimassery Ramaiyar; Murthy, Srikanth; Kumar, Harish; Unnikrishnan, Ambika Gopalakrishnan; Jayakumar, Rohinivilasam Vasukutty

2011-01-01

374

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

375

Artist Projects at Holographics North  

NASA Astrophysics Data System (ADS)

The New York Times has declared the concept of holography in art as "laughably dated". And yet fine art remains one of the most durable applications of the medium. Holographics North Inc. has produced work for over 50 artists in 28 years. In many cases, new techniques and systems were required in order to implement the client's vision. The technical and conceptual challenges involved in several of these projects will be discussed, including photos of the work and the systems built to produce it. Among the artists addressed will be James Turrell, Michael Snow, Frank Stella, Michael Hayden, Harriet Casdin-Silver and Chris Levine.

Perry, John, Dr

2013-02-01

376

Holographic bounds and finite inflation  

E-print Network

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; Albrecht, Andreas

2014-01-01

377

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

2009-03-09

378

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

2013-05-27

379

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 $m_{\\pi^{\\pm}}-m_{\\pi^0}$=4.1 ~ 5.4 MeV, close to the experimental value.

Hong, Deog Ki

2014-01-01

380

Holographic superconductors with hyperscaling violation  

NASA Astrophysics Data System (ADS)

We investigate holographic superconductors in asympototically geometries with hyperscaling violation. The mass of the scalar field decouples from the UV dimension of the dual scalar operator and can be chosen as negative as we want, without disturbing the Breitenlohner-Freedman bound. We first numerically find that the scalar condenses below a critical temperature and a gap opens in the real part of the conductivity, indicating the onset of superconductivity. We further analytically explore the effects of the hyperscaling violation on the superconducting transition temperature. We find that the critical temperature increases with the increasing of hyperscaling violation.

Fan, ZhongYing

2013-09-01

381

Moving through a multiplex holographic scene  

NASA Astrophysics Data System (ADS)

This paper explores how movement can be used as a compositional element in installations of multiplex holograms. My holographic images are created from montages of hand-held video and photo-sequences. These spatially dynamic compositions are visually complex but anchored to landmarks and hints of the capturing process - such as the appearance of the photographer's shadow - to establish a sense of connection to the holographic scene. Moving around in front of the hologram, the viewer animates the holographic scene. A perception of motion then results from the viewer's bodily awareness of physical motion and the visual reading of dynamics within the scene or movement of perspective through a virtual suggestion of space. By linking and transforming the physical motion of the viewer with the visual animation, the viewer's bodily awareness - including proprioception, balance and orientation - play into the holographic composition. How multiplex holography can be a tool for exploring coupled, cross-referenced and transformed perceptions of movement is demonstrated with a number of holographic image installations. Through this process I expanded my creative composition practice to consider how dynamic and spatial scenes can be conveyed through the fragmented view of a multiplex hologram. This body of work was developed through an installation art practice and was the basis of my recently completed doctoral thesis: 'The Emergent Holographic Scene — compositions of movement and affect using multiplex holographic images'.

Mrongovius, Martina

2013-02-01

382

Holographic Brownian motion in dimensional hairy black holes  

NASA Astrophysics Data System (ADS)

In this paper, we investigate the dynamics of a heavy quark for plasmas corresponding to three dimensional hairy black holes. We utilize the AdS/CFT correspondence to study the holographic Brownian motion of this particle with different kinds of hairy black holes. For an uncharged black hole in the low frequency limit we derive analytic expressions for the correlation functions and the response functions and verify that the fluctuation-dissipation theorem holds in the presence of a scalar field against a metric background. In the case of a charged black hole, we think that the results are similar to that derived for an uncharged black hole.

Sadeghi, J.; Pourhassan, B.; Pourasadollah, F.

2014-03-01

383

Fast autonomous holographic adaptive optics  

NASA Astrophysics Data System (ADS)

We present an adaptive optics system incorporating a holographic wavefront sensor with the autonomous closed-loop control of a MEMS deformable mirror. HALOS incorporates a multiplexed holographic recording of the response functions of each actuator in a deformable mirror. On reconstruction with an arbitrary input beam, multiple focal spots are produced. By measuring the relative intensities of these spots a full measurement of the absolute phase can be constructed. Using fast photodiodes, direct feedback correction can be applied to the actuators.In this talk we will present the results from an all-optical, ultra-compact system that runs in closed-loop without the need for a computer. The 32-actuator HALOS runs at a 100kHz bandwidth, but the speed is independent of the number of actuators and should run equally fast with 32 million. Additionally, the system is largely insensitive to obscuration unlike the more conventional Shack-Hartmann WFS. We will present information on how HALOS can be used for image correction and beam propagation as well as several other novel applications.

Andersen, Geoff; Ghebremichael, Fassil; Gelsinger-Austin, Paul; MacDonald, Ken; Gaddipati, Ravi; Gaddipati, Phani

2013-12-01

384

Holographic QCD with Dynamical Flavors  

E-print Network

Gravity solutions describing the Witten-Sakai-Sugimoto model of holographic QCD with dynamical flavors are presented. The field theory is studied in the Veneziano limit, at first order in the ratio of the number of flavors and colors. The gravity solutions are analytic and dual to the field theory either in the confined, low temperature phase or in the deconfined, high temperature phase with small baryonic charge density. The phase diagram and the flavor contributions to vacuum (e.g. string tension and hadron masses) and thermodynamical properties of the dual field theory are then deduced. The phase diagram of the model at finite temperature and imaginary chemical potential, as well as that of the unflavored theory at finite theta angle are also discussed in turn, showing qualitative similarities with recent lattice studies. Interesting degrees of freedom in each phase are discussed. Covariant counterterms for the Witten-Sakai-Sugimoto model are provided both in the probe approximation and in the backreacted case, allowing for a standard holographic renormalization of the theory.

Francesco Bigazzi; Aldo L. Cotrone

2014-10-09

385

Unbalanced holographic superconductors and spintronics  

NASA Astrophysics Data System (ADS)

We present a minimal holographic model for s-wave superconductivity with unbalanced Fermi mixtures, in 2 + 1 dimensions at strong coupling. The breaking of a U(1) A "charge" symmetry is driven by a non-trivial profile for a charged scalar field in a charged asymptotically AdS 4 black hole. The chemical potential imbalance is implemented by turning on the temporal component of a U(1) B "spin" field under which the scalar field is uncharged. We study the phase diagram of the model and comment on the eventual (non) occurrence of LOFF-like inhomogeneous superconducting phases. Moreover, we study "charge" and "spin" transport, implementing a holographic realization (and a generalization thereof to superconducting setups) of Mott's two-current model which provides the theoretical basis of modern spintronics. Finally we comment on possible string or M-theory embeddings of our model and its higher dimensional generalizations, within consistent Kaluza-Klein truncations and brane-anti brane setups.

Bigazzi, Francesco; Cotrone, Aldo L.; Musso, Daniele; Fokeeva, Natalia Pinzani; Seminara, Domenico

2012-02-01

386

Holographic opto-fluidic microscopy.  

PubMed

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

2010-12-20

387

Holographic description of vacuum bubbles  

E-print Network

We discuss a holographic description of vacuum bubbles, with possible implications for a consistent description of the multiverse. In particular, we elaborate on the recent observation by Maldacena, that the interior of AdS bubbles can be described in terms of CFT degrees of freedom living on the worldsheet of the bubble wall. We consider the scattering of bulk gravitons in the ambient parent vacuum, off the bubble wall. In the dual description, the transmission coefficient is interpreted as the probability that a graviton is absorbed by the worldsheet CFT degrees of freedom. The result is in agreement with intuitive expectations. Conformal invariance is not exact in this setup, and the leading corrections due to the IR and UV cut-offs are displayed. Aside from bulk scattering states, we find that when a bubble nucleates within a parent dS vacuum, there is a zero mode of the graviton which describes lower dimensional gravity with a finite Newton's constant. This massless graviton lives within one Hubble radius away from the bubble wall. Possible implications for a fully holographic description of the inflating multiverse are briefly discussed.

Jaume Garriga

2010-12-29

388

Holographic duals of boundary CFTs  

NASA Astrophysics Data System (ADS)

New families of regular half-BPS solutions to 6-dimensional Type 4b supergravity with m tensor multiplets are constructed exactly. Their space-time consists of AdS 2 × S 2 warped over a Riemann surface with an arbitrary number of boundary components, and arbitrary genus. The solutions have an arbitrary number of asymptotic AdS 3 × S 3 regions. In addition to strictly single-valued solutions to the supergravity equations whose scalars live in the coset SO(5 , m) /SO(5) × SO( m), we also construct stringy solutions whose scalar fields are single-valued up to transformations under the U -duality group SO(5 , m; Z), and live in the coset SO(5 , m; Z)SO(5 , m) /SO(5) × SO( m). We argue that these Type 4b solutions are holographically dual to general classes of interface and boundary CFTs arising at the juncture of the end-points of 1+1-dimensional bulk CFTs. We evaluate their corresponding holographic entanglement and boundary entropy, and discuss their brane interpretation. We conjecture that the solutions for which ? has handles and multiple boundaries correspond to the near-horizon limit of half-BPS webs of dyonic strings and three-branes.

Chiodaroli, Marco; D'Hoker, Eric; Gutperle, Michael

2012-07-01

389

Volume holograms in photochromic materials.  

PubMed

Theoretical expressions are derived describing the process of writing volume (or thick) hologram gratings in photochromic materials. The theory includes the effects of the saturation of the material response, scattering of the writing beams by the partially written hologram, and the refractive index changes that accompany the photoinduced absorption changes. Results of representative numerical calculations are presented and interpreted in terms of simpler models and approximations. Use of the results is illustrated by the calculation of the holographic characteristics of an actual material. The results are also related to model photochromic systems to estimate the range of achievable holographic characteristics and to obtain an approximate procedure to estimate the absorption spectra of materials that would give specified holographic characteristics. PMID:20155041

Tomlinson, W J

1975-10-01

390

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

391

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.  

PubMed

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). PMID:23475338

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

2013-04-01

392

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

393

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

394

Holographic tachyon model of dark energy  

Microsoft Academic Search

In this Letter 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

2007-01-01

395

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

2007-02-06

396

Entanglement growth during thermalization in holographic systems  

E-print Network

We derive in detail several universal features in the time evolution of entanglement entropy and other nonlocal observables in quenched holographic systems. The quenches are such that a spatially uniform density of energy ...

Liu, Hong

397

Holographic non-Fermi-liquid fixed points  

E-print Network

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 ...

Faulkner, Tom

398

Meson wave function from holographic approaches  

SciTech Connect

We discuss the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence. We consider two kinds of wave functions obtained in different holographic Soft-Wall approaches.

Vega, Alfredo; Schmidt, Ivan [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Kepler Center for Astro and Particle Physics, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

2010-08-04

399

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

400

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

401

Review of the holographic Lifshitz theory  

NASA Astrophysics Data System (ADS)

We review interesting results achieved in recent studies on the holographic Lifshitz field theory. The holographic Lifshitz field theory at finite temperature is described by a Lifshitz black brane geometry. The holographic renormalization together with the regularity of the background metric allows to reproduce thermodynamic quantities of the dual Lifshitz field theory where the Bekenstein-Hawking entropy appears as the renormalized thermal entropy. All results satisfy the desired black brane thermodynamics. In addition, hydrodynamic properties are further reviewed in which the holographic retarded Green functions of the current and momentum operators are studied. In a nonrelativistic Lifshitz field theory, intriguingly, there exists a massive quasinormal mode at finite temperature whose effective mass is linearly proportional to temperature. Even at zero temperature and in the nonzero momentum limit, a quasinormal mode still remains unlike the dual relativistic field theory. Finally, we account for how adding impurity modifies the electric property of the nonrelativistic Lifshitz theory.

Park, Chanyong

2014-09-01

402

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

2007-05-24

403

Holographic Vortex Liquids and Superfluid Turbulence  

E-print Network

Superfluid turbulence is a fascinating phenomenon for which a satisfactory theoretical framework is lacking. Holographic duality provides a systematic approach to studying such quantum turbulence by mapping the dynamics ...

Chesler, Paul M.

404

Airborne Digital In-Line Holographic System for 3-D Imaging of Cloud Particles  

Microsoft Academic Search

We have developed an airborne holographic instrument for obtaining cloud particle sizes and shapes and their three-dimensional spatial distribution. The primary scientific motivation for the instrument is to provide in-situ measurements of cloud particle spatial correlations, conditioned on particle size. Accurate quantification of spatial correlations at cm-scales and below has been elusive, in part because only one-dimensional spacing data have

J. P. Fugal; E. Saw; A. V. Sergeyev; R. A. Shaw

2003-01-01

405

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

406

Mesoporous silica films with varying porous volume fraction: direct correlation between ortho-positronium annihilation decay and escape yield  

E-print Network

-positronium annihilation decay and escape yield into vacuum L. Liszkay1a , C. Corbel1 , L. Raboin2 , J.-P. Boilot2 , P that permits the determination of the yield and rate of escape of o-Ps into vacuum as well as the annihilation at a threshold porous volume fraction, above which the o-Ps escape rate to vacuum varies linearly with volume

Boyer, Edmond

407

Iron (III)/multiacrylate-based holographic mixtures  

NASA Astrophysics Data System (ADS)

We propose an holographic mixture, based on a nonconventional photoinitiator mixed with an acrylate monomer, in which high resolution thick holographic gratings are written. The used mixture that preferably works at UV and Blue-visible wavelengths shows many interesting features, such as high post-polymerization transparency, high writing resolution, and high angular selectivity. The information is permanently storable. Standard experimental techniques have been used to characterize the physical properties of the written gratings.

Lucchetta, D. E.; Nucara, L.; Criante, L.; Simoni, F.; Boni, A.; Xu, Ji-Hua; Bizzarri, R.; Castagna, R.

2013-11-01

408

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

409

Comparative holographic moire interferometry for nondestructive testing - Comparison with conventional holographic interferometry  

Microsoft Academic Search

The development of comparative holographic moire interferometry is accelerated by the need for nondestructive testing. This paper describes a holographic moire technique for the detection of defects that is based on a comparison of the responses of two macroscopically identical specimens. At identical loading of the master and test objects, the moire fringes obtained are areas of equal differences in

Elly S. Simova; Ventseslav C. Sainov

1989-01-01

410

Retro-Nasal Aroma Release Is Correlated with Variations in the In-Mouth Air Cavity Volume after Empty Deglutition  

PubMed Central

We hypothesized that interindividual differences in motor activities during chewing and/or swallowing were determining factors for the transfer of volatile aroma from the in-mouth air cavity (IMAC) toward the olfactory mucosa. In our first experiment, we looked for changes in IMAC volume after saliva deglutition in 12 healthy subjects. The mean IMAC volume was measured after empty deglutition using an acoustic pharyngometer device. Based on the time course of the IMAC volume after swallowing, we discerned two groups of subjects. The first group displayed a small, constant IMAC volume (2.26 mL ±0.62) that corresponded to a high tongue position. The second group displayed a progressive increase in IMAC (from 6.82 mL ±2.37 to 22.82 mL ±3.04) that corresponded to a progressive lowering of the tongue to its resting position. In our second experiment, we investigated the relationship between IMAC volume changes after deglutition and the level of aroma release at the nostril. For this purpose, the release of menthone was measured at the nostril level in 25 subjects who consumed similar amounts of a mint tablet. The subjects were separated into two groups corresponding to two levels of menthone release: high (H) and low (L). The mean volume of IMAC was measured during and after empty deglutition. Group H displayed a small, constant amplitude of IMAC volume change after deglutition, while Group L displayed a progressive increase in IMAC. It is likely that Group H continuously released the aroma through the veloglossal isthmus as the mint was consumed, while Group L trapped the aroma in the oral cavity and then released it into the nasal cavity upon swallowing. These results show that the in vivo aroma release profile in humans depends closely on the different motor patterns at work during empty deglutition. PMID:22815986

Mishellany-Dutour, Anne; Woda, Alain; Laboure, Helene; Bourdiol, Pierre; Lachaze, Pauline; Guichard, Elisabeth; Feron, Gilles

2012-01-01

411

Defect CFTs and holographic multiverse  

NASA Astrophysics Data System (ADS)

We investigate some aspects of a recent proposal for a holographic description of the multiverse. Specifically, we focus on the implications on the suggested duality of the fluctuations of a bubble separating two universes with different cosmological constants. We do so by considering a similar problem in a 2+1 CFT with a codimension one defect, obtained by an M5-brane probe embedding in AdS4 × S7, and studying its spectrum of fluctuations. Our results suggest that the kind of behavior required by the spectrum of bubble fluctuations is not likely to take place in defect CFTs with an AdS dual, although it might be possible if the defect supports a non-unitary theory.

Fiol, Bartomeu

2010-07-01

412

Holographic QCD with Dynamical Flavors  

E-print Network

Gravity solutions describing the Witten-Sakai-Sugimoto model of holographic QCD with dynamical flavors are presented. The field theory is studied in the Veneziano limit, at first order in the ratio of the number of flavors and colors. The gravity solutions are analytic and dual to the field theory either in the confined, low temperature phase or in the deconfined, high temperature phase with small baryonic charge density. The phase diagram and the flavor contributions to vacuum (e.g. string tension and hadron masses) and thermodynamical properties of the dual field theory are then deduced. The phase diagram of the model at finite temperature and imaginary chemical potential, as well as that of the unflavored theory at finite theta angle are also discussed in turn, showing qualitative similarities with recent lattice studies. Interesting degrees of freedom in each phase are discussed. Covariant counterterms for the Witten-Sakai-Sugimoto model are provided both in the probe approximation and in the backreacted ...

Bigazzi, Francesco

2014-01-01

413

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

414

Information capacity of 3-D holographic data storage  

Microsoft Academic Search

Capacities for angular and wavelength multiplexed holographic data storage systems are considered. Limitations due to the spatial resolution of the recording and reconstructing fields and to the holographic recording process are derived.

D. Brady; D. Psaltis

1993-01-01

415

Holographic recording and light amplification in doped polymer film  

NASA Astrophysics Data System (ADS)

We reported an experimental study of holographic recording and signal light amplification through higher-order diffracted waves from holographic gratings recorded in an acceptor-donor-substituted azobenzene-doped poly(methyl methacrylate) thin film.

Xu, Jingjun; Zhang, Guangyin; Wu, Qiang; Liang, Yumin; Liu, Simin; Sun, Qian; Chen, Xiaobo; Shen, Yuquan

1995-03-01

416

Holographic polymer materials with diffusion development: Principles, arrangement, investigation, and applications  

NASA Astrophysics Data System (ADS)

We present a review of information that has been published in the scientific literature on the mechanism of formation (development, enhancement) of holograms at the expense of the photochemical attachment of phenanthrenequinone molecules and other compounds to polymer chains and diffusion mixing of unreacted molecules, on different types of light-sensitive materials that realize this mechanism, on the application of these materials to create volume holographic elements, on recording of information, and for research purposes.

Veniaminov, A. V.; Mahilny, U. V.

2013-12-01

417

A Note on Holographic Principle in models of Extended Inflation type  

E-print Network

We present a simple derivation of an upper bound on the average size of the true vacuum bubbles at the end of inflation, in models of extended inflation type. The derivation uses the inequality that the total energy inside a given volume must be less than its linear dimensions. The above bound is the same as that obtained earlier, by applying the holographic principle according to Fischler-Susskind prescription. Such a bound leads to a lower bound on the denisty fluctuations.

S. Kalyana rama

1999-08-08

418

A Note on Holographic Principle in models of Extended Inflation type  

E-print Network

We present a simple derivation of an upper bound on the average size of the true vacuum bubbles at the end of inflation, in models of extended inflation type. The derivation uses the inequality that the total energy inside a given volume must be less than its linear dimensions. The above bound is the same as that obtained earlier, by applying the holographic principle according to Fischler-Susskind prescription. Such a bound leads to a lower bound on the denisty fluctuations.

Kalyanaraman, S

1999-01-01

419

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

420

Development of integral holographic motion pictures  

NASA Astrophysics Data System (ADS)

In 1985 Anne-Marie Christakis selected me to make the first pulse holographic feature-fiction movie. Up to that time, the process had only been used for laboratory tests. The running time for the movie was to be 1 minute 20 seconds. Apparently quite long compared with previous tests, but an extremely short time in which to tell a story. I chose the characters of Beauty and the Beast. A lot of time was spent in preparatory work: triple distilling the scenario to get it down to 80 seconds; paintings and masks, and I extracted the music from a suite I had already written in medieval style. The movie was made in 1986 in the laboratory of Professeur Smigielsky, which was located in the Franco-German Defense Research Establishment, at St. Louis in France. Prof. Smigielsky's staff operated all the equipment and Anne-Marie Christakis coordinated everything, as she had done throughout the project. As soon as we arrived at the laboratory, we were told not to look beyond a certain angle towards the laser, otherwise we could be blinded for life. With all that dangerous power however, it was only possible to illuminate a volume for the set of half a meter wide by half a meter deep by one third of a meter high. Such a set gives real meaning to the expression `cramp one's style.' The layout used was, in principle, the same as for making a simple hologram. A pulsed YAG laser was used and each pulse was synchronized with a new frame to be exposed in the camera. When the movie was finished, it was not very bright, and one had to look through a small aperture to view it.

Alexander, P.

1995-02-01

421

Research activities on digital holographic displays in Japan  

Microsoft Academic Search

Recently, researches on digital holographic 3D display are getting very active as well as the digital holography for 3D image acquisition. This paper reviews recent research activities in Japan, including digital holographic 3D video displays, digital holographic fringe printers and computer-generated holograms. The holographic video display includes 100 megapixel full-color full-parallax display, horizontal scanning display, enlarged viewing angle display. For

Hiroshi Yoshikawa

2011-01-01

422

Comparing holographic dark energy models with statefinder  

E-print Network

We apply the statefinder diagnostic to the holographic dark energy models, including the original holographic dark energy (HDE) model, the new holographic dark energy model, the new agegraphic dark energy (NADE) model, and the Ricci dark energy model. In the low-redshift region the holographic dark energy models are degenerate with each other and with the $\\Lambda$CDM model in the $H(z)$ and $q(z)$ evolutions. In particular, the HDE model is highly degenerate with the $\\Lambda$CDM model, and in the HDE model the cases with different parameter values are also in strong degeneracy. Since the observational data are mainly within the low-redshift region, it is very important to break this low-redshift degeneracy in the $H(z)$ and $q(z)$ diagnostics by using some quantities with higher order derivatives of the scale factor. It is shown that the statefinder diagnostic $r(z)$ is very useful in breaking the low-redshift degeneracies. By employing the statefinder diagnostic the holographic dark energy models can be differentiated efficiently in the low-redshift region. The degeneracy between the holographic dark energy models and the $\\Lambda$CDM model can also be broken by this method. Especially for the HDE model, all the previous strong degeneracies appearing in the $H(z)$ and $q(z)$ diagnostics are broken effectively. But for the NADE model, the degeneracy between the cases with different parameter values cannot be broken, even though the statefinder diagnostic is used. A direct comparison of the holographic dark energy models in the $r$--$s$ plane is also made, in which the separations between the models (including the $\\Lambda$CDM model) can be directly measured in the light of the current values $\\{r_0,s_0\\}$ of the models.

Jing-Lei Cui; Jing-Fei Zhang

2014-02-08

423

Estimating the aboveground biomass and wood volume of savanna woodlands in Brazil's Pantanal wetlands based on allometric correlations  

Microsoft Academic Search

The quantity and distribution of vegetal biomass are important aspects to consider in ecosystem studies. However, little information is available about Brazil's Pantanal woodland savannas. This work involved the development of regression equations of the aerial biomass and wood volume of native tree species in a region of woodland savanna on Rio Negro farm in the Pantanal of Nhecolandia, Brazil.

Suzana M. Salis; Marco A. Assis; Patrícia P. Mattos; Antonio C. S. Pião

2006-01-01

424

3-D finite element modeling of human spinal discs and correlation with volume-pressure relation due to loading  

Microsoft Academic Search

A 3-D finite element model has been developed and is being used to analyse the effect of alteration in the nucleus fluid content on the overall mechanics of a lumbar motion segment. The results show that a change in the nucleus volume directly affected the intradiscal pressure. Similar results are also obtained in an experimental study where intradiscal pressures are

A. Shirazi-Adl; H. S. Ranu

1995-01-01

425

Statefinder diagnosis for the interacting model of holographic dark energy  

Microsoft Academic Search

In this Letter, we investigate the holographic dark energy model with interaction between dark energy and dark matter, from the statefinder viewpoint. We plot the trajectories of the interacting holographic dark energy model for different interaction cases as well as for different values of the parameter c in the statefinder-plane. The statefinder diagrams characterize the properties of the holographic dark

Jingfei Zhang; Xin Zhang; Hongya Liu

2008-01-01

426

Multidimensional spatial-spectral holographic interpretation of NMR photography  

Microsoft Academic Search

A spectral holographic interpretation arises naturally in nuclear magnetic resonance (NMR) photography from either the intrinsic chemical shift anisotropy of the spin system or the field inhomogeneity due to the applied spatial encoding gradients. We can thus think of NMR photography as arising from a “diffraction” off a spatial-spectral holographic grating. The spatial holographic component arises from a high dielectric

Andrew J. M. Kiruluta

2006-01-01

427

Multidimensional spatial-spectral holographic interpretation of NMR photography  

Microsoft Academic Search

A spectral holographic interpretation arises naturally in nuclear magnetic resonance (NMR) photography from either the intrinsic chemical shift anisotropy of the spin system or the field inhomogeneity due to the applied spatial encoding gradients. We can thus think of NMR photography as arising from a ``diffraction'' off a spatial-spectral holographic grating. The spatial holographic component arises from a high dielectric

Andrew J. M. Kiruluta

2006-01-01

428

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

429

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

430

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

431

New generation holographic measurement system for industrial nondestructive testing  

Microsoft Academic Search

Advanced achievements in holographic and speckle interferometry, physics of solid-state lasers, digital recording and image processing have created real precondistions for a rising of holographic methods of diagnostics to qualitatively new level. In the present work the general concept of universal holographic system for nondestructive researches in industrial environment is considered and results of tests of some units of this

V. S. Gurevich; M. E. Gusev; V. I. Redkorechev; V. E. Gaponov; I. V. Alexeseenko; A. M. Isaev; A. N. Malov; Yu. N. Zaharov

2005-01-01

432

Nondestructive testing of composite materials by holographic interferometry  

Microsoft Academic Search

Techniques for the nondestructive testing of composites by holographic interferometry are discussed, and results from tests analyzing carbon\\/epoxy composites for two types of defects, resulting from the impact of steel rods and the introduction of mylar inhomogeneities, are presented. Holographic techniques for the interferometric real-time observation of the superposition of the object and the holographic image, and for the recording

J. Ebbeni; M.-A. de Smet

1987-01-01

433

Review of holographic nondestruction evaluation at Lawrence Livermore National Laboratory  

SciTech Connect

At Lawrence Livermore National Laboratory two holographic facilities have been established for the technology transfer of holographic interferometry. This report is a review of the principles of holographic interferometry (HI) and the application of this technique to nondestructive evaluation. Simplified quantitative analysis using a coincident viewing and illumination optical arrangement are described.

Boyd, D.M.

1983-01-01

434

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

435

Parametric study of CHF data. Volume 2. A generalized subchannel CHF correlation for PWR and BWR fuel assemblies. Final report  

SciTech Connect

The primary objective of this research was to develop a generalized subchannel CHF correlation based on the local fluid conditions obtained with the COBRA-IIIC thermal hydraulic subchannel code and covering PWR and BWR normal operating conditions as well as hypothetical loss-of-coolant accident (LOCA) conditions. In view of the importance of the local conditions predicted by the COBRA-IIIC code in the development of CHR correlation, the secondary objective was to improve the predictive capability of the COBRA-IIIC subchannel code. In the first phase of this study, the sensitivity of local enthalpies and local mass fluxes predicted by the COBRA-IIIC subchannel code to subcooled void correlation, bulk void correlation, two-phase friction multiplier correlation and turbulent mixing parameter was determined. In the second phase, based on the local conditions obtained with the COBRA-IIIC subchannel code, an accurate generalized subchannel CHF correlation was developed utilizing 3607 CHF data points from 65 test sections simulating PWR and BWR fuel assemblies.

Reddy, D.G.; Fighetti, C.F.

1983-01-01

436

Universality of Holographic Phase Transitions and Holographic Quantum Liquids  

E-print Network

We explore the phase structure for defect theories in full generality using the gauge/gravity correspondence. On the gravity side, the systems are constructed by introducing M (probe) D(p+4-2k)-branes in a background generated by N Dp-branes to obtain a codimension-k intersection. The dual gauge theory is a U(N) Supersymmetric Yang-Mills theory on a (1+p-k)-dimensional defect with both adjoint and fundamental degrees of freedom. We focus on the phase structure in the chemical potential versus temperature plane. We observe the existence of two universality classes for holographic gauge theories, which are identified by the order of the phase transition in the interior of the chemical potential/temperature plane. Specifically, all the sensible systems with no defect show a third order phase transition. Gauge theories on a defect with (p-1)-spatial directions are instead characterised by a second order phase transition. One can therefore state that the order of this phase transition is intimately related to the codimensionality of the defect. We also discuss the massless hypermultiplet at low temperature, where a thermodynamical instability seems to appear for $p<3$. Finally, we comment on such an instability.

Paolo Benincasa

2009-10-31

437

Didactical Holographic Exhibit Including Holo TV (holographic Television)  

NASA Astrophysics Data System (ADS)

Our Institute of Physics exposes since 1980 didactical exhibitions of holography in Brazil where nice holograms are shown altogether with basic experiments of geometric and wave optics. This experiments lead to the understanding of the phenomenon of images of an ample way. Thousands of people have been present at them, in their majority of the Universidade Estadual de Campinas, where since 2002 they have taken the format of a course without formal evaluation. This way the exhibition has been divided in four modules, in each one of them are shown different holograms, experiments of optics and applications of diffractive images with white light developed in the Institute of Physics. The sequence of the learning through the modules begins with the geometric optics, later we explain the wave optics and finally holography. The phenomenon of the diffraction in daily elements is shown experimentally from the beginning. As well as the application of the holographic screens in white light: the television images that appear in front of the screen and the spectator can try to experience the reality illusion. Put something so exclusive (that only exists in the laboratory) to the public is a way to approximate the persons to an investigation in course. The vision of images that seem to be of holograms, but in movement, and size of until a square meter completes this exhibition of an exclusive way in the world.

Lunazzi, José J.; Magalhães, Daniel S. F.; Rivera, Noemí I. R.

2008-04-01

438

The energy performance of prototype holographic glazings  

NASA Astrophysics Data System (ADS)

We report on the simulation of the energy performance of prototype holographic glazings in commercial office buildings in a California climate. These prototype glazings, installed above conventional side windows, are designed to diffract the transmitted solar radiation and reflect it off the ceiling, providing adequate daylight illumination for typical office tasks up to 10m from the window. In this study, we experimentally determined a comprehensive set of solar-optical properties and characterized the contribution of the prototype holographic glazings to workplane illuminance in a scale model of a typical office space. We then used the scale model measurements to simulate the energy performance of the holographic glazings over the course of an entire year for four window orientations (North, East, South and West) for the inland Los Angeles climate, using the DOE-2.lD building energy analysis computer program. The results of our experimental analyses indicate that these prototype holographic glazings diffract only a small fraction of the incident light. The results of this study indicate that these prototype holographic glazings will not save energy in commercial office buildings. Their performance is very similar to that of clear glass, which, through side windows, cannot efficiently illuminate more than a 4-6 m depth of a building's perimeter, because the cooling penalties due to solar heat gain are greater than the electric lighting savings due to daylighting.

Papamichael, K.; Beltran, L.; Furler, R.; Lee, E. S.; Selkowitz, S.; Rubin, M.

1993-02-01

439

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

440

Tracking the roots of reading ability: white matter volume and integrity correlate with phonological awareness in prereading and early-reading kindergarten children.  

PubMed

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

Saygin, Zeynep M; Norton, Elizabeth S; Osher, David E; Beach, Sara D; Cyr, Abigail B; Ozernov-Palchik, Ola; Yendiki, Anastasia; Fischl, Bruce; Gaab, Nadine; Gabrieli, John D E

2013-08-14

441

Structure-function relationships in the stem cell's mechanical world B: emergent anisotropy of the cytoskeleton correlates to volume and shape changing stress exposure.  

PubMed

In the preceding study (Part A), we showed that prescribed seeding conditions as well as seeding density can be used to subject multipotent stem cells (MSCs) to volume changing stresses and that changes in volume of the cell are associated with changes in shape, but not volume, of the cell nucleus. In the current study, we aim to control the mechanical milieu of live cells using these prescribed seeding conditions concomitant to delivery of shape changing stresses via fluid flow, while observing adaptation of the cytoskeleton, a major cellular transducer that modulates cell shape, stiffness and remodeling. We hypothesize that the spatiotemporal organization of tubulin and actin elements of the cytoskeleton changes in response to volume and shape changing stresses emulating those during development, prior to the first beating of the heart or twitching of muscle. Our approach was to quantify the change over baseline in spatiotemporal distribution of actin and tubulin in live C3H/10T1/2 model stem cells subjected to volume changing stresses induced by seeding at density as well as low magnitude, short duration, shape changing (shear) stresses induced by fluid flow (0.5 or 1.0 dyne/cm2 for 30/60/90 minutes). Upon exposure to fluid flow, both tubulin thickness (height) and concentration (fluorescence intensity) change significantly over baseline, as a function of proximity to neighboring cells (density) and the substrate (apical-basal height). Given our recently published studies showing amplification of stress gradients (flow velocity) with increasing distance to nearest neighbors and the substrate, i.e. with decreasing density and toward the apical side of the cell, tubulin adaptation appears to depend significantly on the magnitude of the stress to which the cell is exposed locally. In contrast, adaptation of actin to the changing mechanical milieu is more global, exhibiting less significant differences attributable to nearest neighbors or boundaries than differences attributable to magnitude of the stress to which the cell is exposed globally (0.5 versus 1.0 dyne/cm2). Furthermore, changes in the actin cytoskeletal distribution correlate positively with one pre-mesenchymal condensation marker (Msx2) and negatively with early markers of chondrogenesis (ColIIaI alone, indicative of pre-hypertrophic chondrogenesis) and osteogenesis (Runx2). Changes in the tubulin cytoskeletal distribution correlate positively with a marker of pericondensation (Sox9 alone), negatively with chondrogenesis (ColIIaI) and positively with adipogenesis (Ppar-gamma 2). Taken as a whole, exposure of MSCs to volume and shape changing stresses results in emergent anisotropy of cytoskeletal architecture (structure), which relate to emergent cell fate (function). PMID:22338708

Chang, Hana; Knothe Tate, Melissa L

2011-12-01

442

Anatomy of new SUSY breaking holographic RG flows  

E-print Network

We find and thoroughly study new supergravity domain wall solutions which are holographic realizations of supersymmetry breaking strongly coupled gauge theories. We set ourselves in an N=2 gauged supergravity with a minimal content in order to reproduce a dual N=1 effective SCFT which has a U(1)_R symmetry, a chiral operator whose components are responsible for triggering the RG flow, and an additional U(1)_F symmetry. We present a full three dimensional parameter space of solutions, which generically break supersymmetry. Some known solutions are recovered for specific sets of values of the parameters, with the new solutions interpolating between them. The generic backgrounds being singular, we provide a stability test of their dual theories by showing that there are no tachyonic resonances in the two point correlators. We compute the latter by holographic renormalization. We also carefully analyze the appearance of massless modes, such as the dilaton and the R axion, when the respective symmetries are spontaneously broken, and their lifting when the breaking is explicit. We further comment on the application of such class of backgrounds as archetypes of strongly coupled hidden sectors for gauge mediation of supersymmetry breaking. In particular, we show that it is possible to model in this way all types of hierarchies between the visible sector gaugino and sfermion masses.

Riccardo Argurio; Daniele Musso; Diego Redigolo

2014-11-10

443

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