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Image scale measurement with correlation filters in a volume holographic optical correlator  

NASA Astrophysics Data System (ADS)

A search engine containing various target images or different part of a large scene area is of great use for many applications, including object detection, biometric recognition, and image registration. The input image captured in realtime is compared with all the template images in the search engine. A volume holographic correlator is one type of these search engines. It performs thousands of comparisons among the images at a super high speed, with the correlation task accomplishing mainly in optics. However, the inputted target image always contains scale variation to the filtering template images. At the time, the correlation values cannot properly reflect the similarity of the images. It is essential to estimate and eliminate the scale variation of the inputted target image. There are three domains for performing the scale measurement, as spatial, spectral and time domains. Most methods dealing with the scale factor are based on the spatial or the spectral domains. In this paper, a method with the time domain is proposed to measure the scale factor of the input image. It is called a time-sequential scaled method. The method utilizes the relationship between the scale variation and the correlation value of two images. It sends a few artificially scaled input images to compare with the template images. The correlation value increases and decreases with the increasing of the scale factor at the intervals of 0.8~1 and 1~1.2, respectively. The original scale of the input image can be measured by estimating the largest correlation value through correlating the artificially scaled input image with the template images. The measurement range for the scale can be 0.8~4.8. Scale factor beyond 1.2 is measured by scaling the input image at the factor of 1/2, 1/3 and 1/4, correlating the artificially scaled input image with the template images, and estimating the new corresponding scale factor inside 0.8~1.2.

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



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



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)



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



Volume reflection holographic confocal imaging.  


The Denisyuk volume reflection hologram is produced with spatially incoherent light to form an image-plane hologram. The image formed in readout combines the properties of volume holography and confocal image formation. PMID:18349989

Yang, G G; Chen, H S; Leith, E N



Study on spectrometer based upon volume holographic transmission grating  

NASA Astrophysics Data System (ADS)

In this present paper, a spectrometer based upon axial transmissive optical structure with the volume-phase holographic (VPH) transmission grating technology is introduced. We give a physical insight for the structure and mechanism of photorefractive volume holographic gratings and theoretically analyze some important performance parameters of the spectrometer device using the coupled wave theory, which should be considered in the process of the following design for the device with volume phase holographic transmission gratings. The experimental results show, owing to its axial transmissive optical geometry and the perfect performance of the VPH transmission grating, the spectrometer based on the volume-phase holographic transmission grating has satisfactory high resolution and wavelength accuracy. It has great promise to be widely used in the future.

Huang, Zhen; Liu, Guodong; Ren, Zhong; Zeng, Lvming



Nonlinear equation for volume holographic memory  

NASA Astrophysics Data System (ADS)

The signal distortion can result in unacceptable bit error rate in data storage system. The low-pass nature of system is one of the significant sources of the signal distortion in the volume holographic memory (VHM). The current research interesting is how to improve the signal performance and enhance the reliability of VHM.A reduced channel model is developed to investigate the low-pass nature of the VHM. Specially, the influence on the signal from the low-pass nature of VHM is characterized by the inter-pixel interference (IPI) in a data page. Recently, some reseachers has adopted and proposed the linear transversal filter in order to cope with the IPI. However, the intensity measurement derived from the CCD is not a simple linear combination of the data. In some cases, its performance can't approach to the optimal solution. In this works, a new multiplayer percpetion based on nonlinear equalizer is introduced to counter IPI, the simulation result show that the performance of such a nonlinear equalizer is superior to that of the linear equalizer.

Liu, Jibin; Xie, Changsheng; Pei, Xiandeng



Reliability of content-addressable data search in a defocused volume holographic data storage system.  


We investigate for suitable methods that enable reliable content-addressable data search in a defocused volume holographic data storage system. Two techniques have been introduced and are shown to overcome the shortcomings of the known methods used to perform content searching in defocused holographic recording geometry. In effect, we remove the deterministic errors that result because of the presence of nonmatching database records, producing almost the same correlation scores as the true targeted correlation scores. Such deterministic errors give rise to erroneous search outcomes and reduce the speed advantage of the parallel holographic data search. We present experimental results and discuss the improvements offered by the two introduced methods in terms of storage density and measured correlation scores. Both the methods of modified-balanced and 25% sparse modulation coded data pages are found to produce good results, negating the undesired correlation characteristics. PMID:20154744

Das, Bhargab; Joseph, Joby; Singh, Kehar



Volume polarization holographic recording in thick photopolymer for optical memory.  


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



Doped photopolymers for volume holographic applications  

NASA Astrophysics Data System (ADS)

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

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



Volume Phase Holographic Gratings: Polarization Properties and Diffraction Efficiency  

Microsoft Academic Search

We discuss the polarization properties and first-order diffraction efficiencies of volume phase holographic (VPH) transmission gratings, which can be exploited to improve the throughput of modern spectrographs. The wavelength of peak efficiency can be tuned by adjustment of the incidence angle. We show that the variation of the Kogelnik efficiency versus Bragg angle depends only on one parameter, given by

I. K. Baldry; J. Bland-Hawthorn; J. G. Robertson



Polymer-based volume holographic grating couplers for optical interconnects  

Microsoft Academic Search

Volume holographic grating couplers (VHGCs) are become increasingly attractive devices for the application of optical interconnects because of their higher preferential coupling, dry fabrication processing, and low cost. Moreover, for many practical cases for high-data rate interconnects, the needed gratings have limited spatial apertures and are usually illuminated by finite-width beams, such as Gaussian beams. In order to design and

Shun-Der Wu



Holographic correlators for general gauge mediation  

NASA Astrophysics Data System (ADS)

We use holographic techniques to compute two-point functions of operators belonging to a conserved current supermultiplet in theories which break supersymmetry at strong coupling. These are the relevant quantities one has to compute in models of gauge mediation to determine the soft spectrum in supersymmetric extensions of the Standard Model (SSM). Such holographic approach can be used for diverse gravitational backgrounds, but here we focus, for definiteness, on asymptotically AdS backgrounds. After presenting the general framework, we apply our formulas to two explicit examples which differ by the nature of the SSM gauginos, which have Dirac or Majorana masses, corresponding to models that respectively preserve or break R-symmetry.

Argurio, Riccardo; Bertolini, Matteo; Di Pietro, Lorenzo; Porri, Flavio; Redigolo, Diego



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.



Volume Phase Holographic Gratings: Polarization Properties and Diffraction Efficiency  

Microsoft Academic Search

We discuss the polarization properties and first-order diffraction\\u000aefficiencies of volume phase holographic (VPH) transmission gratings, which can\\u000abe exploited to improve the throughput of modern spectrographs. The wavelength\\u000aof peak efficiency can be tuned by adjustment of the incidence angle. We show\\u000athat the variation of the Kogelnik efficiency versus Bragg angle depends only\\u000aon one parameter, given by

J. Bland-Hawthorn



Volume phase holographic echelle grating: a theoretical study  

NASA Astrophysics Data System (ADS)

Volume phase holographic gratings (VPHGs) are becoming fundamental dispersing elements in astronomical instrumentation. Here it will be described the efficiency behavior of such dispersing elements at high diffraction orders for understanding the possible use as echelle gratings. The efficiency is calculated based on RCWA analysis and different parameters are changed/optimized, i.e film thickness, refractive index modulation and profile. The results show that the VPHGs are not suitable for working at high orders in the classical configurations.

Bianco, Andrea; Pariani, Giorgio



Analytical treatment of the polychromatic spatially multiplexed volume holographic grating.  


An alternative model to N-coupled wave theory of the spatially multiplexed finite thickness volume holographic reflection grating is developed from the parallel stacked mirrors (PSM) model in terms of N infinite arrays of parallel stacked mirrors each characterized by a different grating vector. A plane reference wave interacts with each of the N sets of stacked mirrors, producing N signal waves. First-order coupled partial differential equations describing the detailed process of Fresnel reflection within the grating are derived for the reference and N signal waves. These equations can be solved analytically at Bragg resonance where agreement with conventional N-coupled wave theory is exact. The new model is compared for the case of some simple multiplexed volume phase reflection gratings at and away from Bragg resonance with a rigorous coupled-wave solution of the Helmholtz equation. Good agreement is attained for even rather high values of index modulation. For lower modulations more characteristic of modern holographic materials, agreement appears extremely good at and around Bragg resonance, although differences inevitably appear in the higher-order diffractive sideband structure. The analytic model is extended to cover polychromatic spatially multiplexed volume phase gratings at Bragg resonance, where once again agreement with rigorous coupled-wave calculations is very good for index modulations typical for modern holographic gratings. Finally, the model is extended to cover the case of the lossless multicolor phase-reflection hologram, where analytic and graphical results are presented concerning diffractive efficiency. PMID:23089771

Brotherton-Ratcliffe, David



Polymer-based volume holographic grating couplers for optical interconnects  

NASA Astrophysics Data System (ADS)

Volume holographic grating couplers (VHGCs) are become increasingly attractive devices for the application of optical interconnects because of their higher preferential coupling, dry fabrication processing, and low cost. Moreover, for many practical cases for high-data rate interconnects, the needed gratings have limited spatial apertures and are usually illuminated by finite-width beams, such as Gaussian beams. In order to design and characterize the performance of finite-size volume holographic gratings, a rigorous method of analysis is needed. In this work, the finite-difference frequency-domain (FDFD) method is applied to analyze rigorously both unslanted and slanted finite-number-of-periods gratings and is compared to the rigorous coupled-wave analysis (RCWA). Furthermore, the FDFD method is adapted for the analysis of VHGCs and is compared to the RCW A/leak-mode approach. Both output and input grating couplers, which are placed either in the waveguide film region or in the waveguide cover region, are investigated in this research. On the other hand, the DuPont OmniDex613 photopolymers are used to fabricate VHGCs in the experiment. In order to obtain a holographic grating with higher refractive-index modulation and thus higher diffraction efficiency, both the theoretical analysis of a nonlocal diffusion model solved rigorously by use of the finite-difference time-domain (FDTD) method and the experimental techniques of real-time diffraction-monitoring and angular-selectivity measurements are applied to study the optimization of holographic recording process. Finally, a VHGC in the waveguide cover region is designed, fabricated, and tested.

Wu, Shun-Der


Reliability of associative recall based on data manipulations in phase encoded volume holographic storage systems  

NASA Astrophysics Data System (ADS)

We investigate the characteristics of correlation signals accomplished by content addressing in a phase encoded volume holographic storage system under different realistic conditions. In particular, we explore two crucial cases with respect to the structure of the data. The first one deals with a scenario where only partial or defective data are available for content addressing. The second case takes similarities among the stored data sets into account, which significantly differ from their statistical correlation. For both the cases we provide, for the first time, a theoretical approach and present experimental results when employing phase-code multiplexing. Finally, we discuss the reliability of the employed methods.

Berger, G.; Stumpe, M.; Höhne, M.; Denz, C.



Aspects of current correlators in holographic theories with hyperscaling violation  

NASA Astrophysics Data System (ADS)

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

Edalati, Mohammad; Pedraza, Juan F.



Slanted fringe volume phase holographic gratings in astronomical instrumentation  

NASA Astrophysics Data System (ADS)

Many existing astronomical spectrographs have been retrofitted with volume phase holographic gratings (VPHGs), since at higher line density they are significantly more efficient than surface relief transmission gratings. Designing the spectrograph around the VPHG offers additional advantages. In this paper we describe slanted fringe VPHG that are considered as cross-disperser / beam expander in high-resolution echelle spectrographs for the Combined Incoherent Focus of the VLT and the E-ELT. We will present simulations of diffraction efficiency of slanted fringe VPHGs that explore the useful parameter space of these devices in terms of efficiency, line density and anamorphic beam expansion.

Arns, James A.; Dekker, Hans



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

ERIC Educational Resources Information Center

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

Owen, Harry



Volume holographic optical elements for point-to-point imaging with local cross talk.  


A novel volume holographic optical element serving as an atypical mirror with a lateral magnification of 1 in both the horizontal and the vertical directions is proposed. Optical imaging is performed by point-to-point imaging with local cross talk, which prevents ghost diffraction spots from the holographic element of multiple gratings. PMID:16315706

Teng, Tun-Chien; Ou, Po-Chi; Sun, Ching-Cherng



Range correlator demonstrated in 0.5 GHz spectral holographic gratings at 1.5 microns  

Microsoft Academic Search

We demonstrate large bandwidth (0.5 GHz) range correlation in a spectral-spatial holographic (SSH) material under practical conditions. Adaptation of this work to a range Doppler correlator over the same bandwidth is a prospect of future work.

Z. Cole; K. M. Rupavatharam; K. D. Merkel; T. Bottger; W. R. Babbitt; R. L. Cone



Volume holographic lenses and their applications in white light imaging and concentration of solar energy  

NASA Astrophysics Data System (ADS)

In this paper we present the design and development of volume holographic lenses for white light imaging and solar energy concentration. Details of design analysis and process of manufacturing of these lenses on dichromated gelatin is also given.

Shakher, Chandra; Sirohi, Rajpal S.



Cross-talk noise in volume holographic memory with spherical reference beams  

NASA Astrophysics Data System (ADS)

We investigate angle-multiplexed volume holographic memory with spherical reference beams, for which the spherical approximation is made to model the wave-front distortion in general. We find that the angular selectivity and the cross-talk noise with spherical reference beams are close to those with planar reference beams. The results indicate that angle-multiplexed volume holographic memory can be realized in compact systems for which large wave-front distortion is expected.

Yi, Xianmin; Yeh, Pochi; Gu, Claire



PQ:DMNA/PMMA photopolymer having amazing volume holographic recording at wavelength of insignificant absorption.  


N, N-dimethyl-4-nitroaniline doping enables red-light holographic recording that was originally insensitive in thick phenanthrenequinone/poly(methyl methacrylate) photopolymer to have reasonable sensitivity. A volume hologram was recorded by a 647 nm laser with maximum diffraction efficiency of about 43% in a 2-mm-thick sample. A Bragg selectivity curve and an image hologram reconstruction are also demonstrated. These experimental results support recording material for volume holographic applications in an extended red spectral range. PMID:23938975

Chen, Yu-Fang; Lin, June-Hua; Lin, Shiuan Huei; Hsu, Ken Y; Whang, Wha-Tzong



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

PubMed Central

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

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



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.



Cell volume changes during apoptosis monitored in real time using digital holographic microscopy.  


Cellular volume changes play important roles in many processes associated with the normal cell activity, as well as various diseases. Consequently, there is a considerable need to accurately measure volumes of both individual cells and cell populations as a function of time. In this study, we have monitored cell volume changes in real time during apoptosis using digital holographic microscopy. Cell volume changes were deduced from the measured phase change of light transmitted through cells. Our digital holographic experiments showed that after exposure to 1 ?M staurosporine for 4 h, the volumes of KB cells were reduced by ~50-60%, which is consistent with previous results obtained using electronic cell sizing and atomic force microscopy. In comparison with other techniques, digital holographic microscopy is advantageous because it employs noninvasive detection, has high time resolution, real time measurement capability, and the ability to simultaneously investigate time-dependent volume changes of both individual cells and cell populations. PMID:22465356

Khmaladze, Alexander; Matz, Rebecca L; Epstein, Tamir; Jasensky, Joshua; Banaszak Holl, Mark M; Chen, Zhan



Particle image identification and correlation analysis in microscopic holographic particle image velocimetry  

SciTech Connect

This paper discusses the different analysis methods used in holographic particle image velocimetry to measure particle displacement and compares their relative performance. A digital holographic microscope is described and is used to record the light scattered by particles deposited on cover slides that are displaced between exposures. In this way, particle position and displacement are controlled and a numerical data set is generated. Data extraction using nearest neighbor analysis and correlation of either the reconstructed complex amplitude or intensity fields is then investigated.

Wormald, S. Andrew; Coupland, Jeremy



Computer simulation of reflective volume grating holographic data storage.  


The shift selectivity of a reflective-type spherical reference wave volume hologram is investigated using a nonparaxial numerical modeling based on a multiple-thin-layer implementation of a volume integral equation. The method can be easily parallelized on multiple computers. According to the results, the falloff of the diffraction efficiency due to the readout shift shows neither Bragg zeros nor oscillation with our parameter set. This agrees with our earlier study of smaller and transmissive holograms. Interhologram cross talk of shift-multiplexed holograms is also modeled using the same method, together with sparse modulation block coding and correlation decoding of data. Signal-to-noise ratio and raw bit error rate values are calculated. PMID:17728833

Gombköt, Balázs; Koppa, Pál; Süt, Attila; L Rincz, Em Ke



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



Compact Fourier-transform volume holographic spectrometer for diffuse source spectroscopy.  


We present a new idea for diffuse source spectroscopy using a Fourier-transform volume holographic spectrometer formed by a Fourier-transform lens, a volume hologram, and a CCD. We show that this spectrometer can operate well under spatially incoherent light illumination. Furthermore, this spectrometer is less bulky, less sensitive to input alignment, and potentially more appropriate for implementation of highly sensitive spectrometers than conventional spectrometers. PMID:15865371

Hsieh, Chaoray; Momtahan, Omid; Karbaschi, Arash; Adibi, Ali



Position feedback system for volume holographic storage media  


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)



Volume holographic recording utilizing photo-initiated polymerization for nonvolatile digital data storage  

NASA Astrophysics Data System (ADS)

Volume holographic recording offers an attractive solution for next generation digital storage with high density (>=10 Gb/cm 2) and transfer rate (Gb/sec). In holographic storage, data is recorded as volume phase gratings (refractive index modulation) in an optical medium. The system performance is practically determined by the physical characteristics of the recording medium. Photorefractive crystals, the most extensively investigated volumetric media, offer sensitive but typically volatile recording. Recent advancements in photo-polymerizable media have offered an attractive alternative for nonvolatile storage. This thesis evaluates the important physical properties of volume holographic recording in a photo-polymerizable material. Formation of permanent compositional volume phase gratings through monomer photopolymerization has offered a very sensitive recording mechanism, but limitations were also reported during and after exposure. The previous studies of photopolymerization recording response suggested reciprocity failure at high intensity (I), and large grating spacing (?). Grating formation was described through a photo-induced reaction diffusion model that ignores post- exposure polymerization, suggesting diffusion ( D) limited medium response to improve for longer, e.g. multipulse, recording schedules. In this thesis, the dynamics of grating formation are, for the first time, investigated extensively with respect to I, and ?, in a material utilizing cationing-ring-opening polymerization (CROP Polaroid). Holographic recording is evaluated in standard (pretreated ULSH500) CROP samples for constant exposure energy (15mJ/cm 2), i.e. total number of photons, but for a wide range of different I (mW/cm2 - W/cm2), i.e. incident photon rates, and for a few ? (?m), i.e. diffusion scales. CROP grating evolution is diffusion limited for recording with short (? r) high I (>W/ cm2) pulses. Grating formation, however, is photo-initiated (rather than photo-induced), significantly continuing after short pulse illumination. This previously unaccounted, post-exposure grating development yields strong highly sensitive (~3 cm/mJ) final CROP gratings, without reciprocity or diffusion limitations. Based on these observations, a new physical model for holographic recording in materials utilizing photo- initiated polymerization has been developed, that accounts successfully for grating evolution and post- exposure development. The model explains that diffusive transport (?d = ?2/D) limits grating evolution for ? r < ?d. Nevertheless, high final CROP response arises independent of the temporal recording characteristics, due to the post- exposure contributions. In conclusion, this thesis evaluates the performance of the CROP medium in a non-volatile holographic (WORM) storage digital system. Volume recording of CROP gratings offers attractive additive multi-pulse development, with efficient photo-initiation, and polymerization, independent of I and ?, scaling linearly with exposure (<=15 mJ/ cm2), and allowing flexible recording scheduling.

Paraschis, Loukas


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


We present a new passive depth detection method for quasi-monochromatic and spatially incoherent objects. We utilize the wavefront discrimination properties of a volume holographic pupil combined with a measurement of the degree of coherence of the diffracted field. Depth detection is posed as the Bayesian hypothesis testing on the outcome of the coherence measurement. We present the analysis of our proposed optical system and experimental results confirming binary depth discrimination with high confidence for featureless objects. PMID:19104541

Oh, Se Baek; Barbastathis, George



Stabilization system for holographic recording of volume Bragg gratings using a corner cube retroreflector.  


Volume Bragg gratings serve an important role in laser development as devices that are able to manipulate both the wavelength and angular spectrum of light. A common method for producing gratings is holographic recording of a two collimated beam interference pattern in a photosensitive material. This process requires stability of the recording system at a level of a fraction of the recording wavelength. A new method for measuring and stabilizing the phase of the recording beams is presented that is extremely flexible and simple to integrate into an existing holographic recording setup and independent of the type of recording media. It is shown that the presented method increases visibility of an interference pattern and for photo-thermo-refractive glass enables enhancement of the spatial refractive index modulation. The use of this technique allows for longer recording times that can lead to the use of expanded recording beams for large aperture gratings. PMID:24663299

Ott, Daniel B; Divliansky, Ivan B; Segall, Marc A; Glebov, Leonid B



Statistical analysis of cross-talk noise and storage capacity in volume holographic memory: image plane holograms  

NASA Astrophysics Data System (ADS)

We investigate the cross-talk noise in optical storage based on angle-multiplexed image plane volume holograms. Simple expressions for the signal-to-noise ratio and the storage density are obtained. The cross-talk noise is found to limit the size of the pixels and the number of recorded holograms. The cross-talk-limited storage density of image plane holographic storage is found to be close to that of Fourier plane holographic storage.

Yi, Xianmin; Campbell, Scott; Yeh, Pochi; Gu, Claire



Photopolymer-based volume phase holographic grating for astronomical instrumentations  

NASA Astrophysics Data System (ADS)

Green sensitive photopolymers have been studied to produce volume phase gratings (VPHGs) to be used as dispersing elements in astronomical instrumentations. They have been characterized determining the parameters that affect the diffraction efficiency (thickness, refractive index modulation, exposure, line density, etc.). Different prototypes have been produced varying all the selected parameters. The optical proprieties of the devices were investigated to understand the quality of the gratings. The results were encouraging, therefore, to experience the possibility to produce a VPHG for astronomical applications, low dispersion prototype has been designed, and it will be mounted in the AFOSC camera (Asiago, Italy).

Zanutta, Alessio; Bianco, Andrea; Zerbi, Filippo Maria



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


We present results from cryogenic tests of volume-phase holographic (VPH) gratings at approximately 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 ten cycles between room temperature and 100 K and find no clear evidence that the diffraction efficiency changes with temperature or with a successive thermal cycle. PMID:16926880

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



Transmitted wavefront error of a volume phase holographic grating at cryogenic temperature.  


This paper describes the results of transmitted wavefront error (WFE) measurements on a volume phase holographic (VPH) grating operating at a temperature of 120 K. The VPH grating was mounted in a cryogenically compatible optical mount and tested in situ in a cryostat. The nominal root mean square (RMS) wavefront error at room temperature was 19 nm measured over a 50 mm diameter test aperture. The WFE remained at 18 nm RMS when the grating was cooled. This important result demonstrates that excellent WFE performance can be obtained with cooled VPH gratings, as required for use in future cryogenic infrared astronomical spectrometers planned for the European Extremely Large Telescope. PMID:22660099

Lee, David; Taylor, Gordon D; Baillie, Thomas E C; Montgomery, David



A compact lensless and slitless volume holographic spectrometer for diffuse source spectroscopy  

NASA Astrophysics Data System (ADS)

We present a simple, very compact, and inexpensive spectrometer for diffuse source spectroscopy using only a volume hologram (recorded by two spherical beams) and a CCD camera (or a detector array). We show that this spectrometer can operate well under spatially incoherent light illumination. We also show that the resolution of this spectrometer can be optimized by proper selection of the location of the CCD camera (or the detector array). The results show the possibility of using optimized holographic optical elements as the integrated collimating, dispersive, and light-collective components of spectrometers.

Hsieh, C.; Momtahan, O.; Karbaschi, A.; Adibi, A.



Dynamic characterizations of high diffraction efficiency in volume Bragg grating formed by holographic photopolymerization  

NASA Astrophysics Data System (ADS)

Volume Bragg grating with 96% diffraction efficiency (DE) was efficiently formed by holographic photopolymerization in blend syrup of photocurable trimethylolpropane triacrylate monomer and nematic liquid crystal. The formation dynamics of the composite gratings was quantitatively characterized under the frame of one-dimensional reaction-diffusion model with a revision of individual decay constants for monomer diffusion and reaction. Initial parameters of diffusion and reaction were analytically determined from the measured first order DE at the beginning stage. Evolutions of the DE, both in curing and postcuring periods, were excellently simulated, especially with postcuring reaction been taken into account.

Pu, Haihui; Yin, Dejin; Gao, Bin; Gao, Hongyue; Dai, Haitao; Liu, Jianhua



Low spatial frequency characterization of holographic recording materials applied to correlation  

NASA Astrophysics Data System (ADS)

In this work we expose the results obtained with a wide variety of phase holographic recording materials that we have characterized in the range of low spatial frequencies (<= 32 lines/millimeter). We have considered bleached photographic emulsion, silver halide sensitized gelatin and dichromated gelatin. This low spatial frequency characterization is necessary in order to generate optimum computer-generated holograms on these materials by means of a low cost technique. In this work, we have generated correlation filters for optical pattern recognition. The experimental results confirm that the correlation filters generated on all the phase materials exhibit a good performance.

Marquez, Andres; Belendez, Augusto; Campos, Juan; Pascual, Inmaculada V.; Yzuel, Maria J.; Fimia, Antonio; Neipp, Cristian



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.



Slanted volume holographic gratings design based on rigorous coupled-wave analysis  

NASA Astrophysics Data System (ADS)

A model for slanted volume holographic grating based on the rigorous coupled-wave analysis (RCWA) is proposed and analyzed. In this model an oblique coordinate system related to the grating fringes simplifies the mathematical analysis. And the S-matrix algorithm gives the RCWA results. Based on the vector theory, the RCWA can present more details of the diffraction process. Compared with the traditional approximate theory, the RCWA for volume grating can analyze the angular selectivity and the diffraction efficiency more accurately and flexibly. Through the simulation results, the Fresnel diffraction on the interface can be analyzed. The effect of the grating fringe error the grating is also provided. The effect of the grating thickness, an important grating parameter, has been described particularly.

Li, Ting; Cao, Liangcai; He, Qingsheng; Jin, Guofan



Optimal resolution in Fresnel incoherent correlation holographic fluorescence microscopy.  


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



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.

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



Raman Spectroscopy and Microscopic Raman Imaging with Applications of Volume Holographic Optical Elements  

Microsoft Academic Search

Holographic optical elements are crucial for the development of compact and efficient Raman spectroscopic instrumentation. Holographic optics allow direct coupling of a single-stage spectrograph to a Raman microprobe. The high transmission efficiency and narrow rejection-band characteristics of the holographic beam splitter provide efficient use of low power lasers, while allowing acquisition of low-frequency Raman spectra. The holographic notch filter and

David Mark Pallister



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

NASA Astrophysics Data System (ADS)

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

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



Separation of LP modes using volume holographic demultiplexer with a dual-wavelength method for mode division multiplexing  

NASA Astrophysics Data System (ADS)

We propose a volume holographic mode demultiplexer incorporating a dual-wavelength method, which enables us to easily and flexibly set up the receiving system in mode division multiplexing for a large number of mode multiplexing. This demultiplexer can separate a lot of multiplexed modes with different wavelengths through angularly hologram multiplexing by appropriate angular difference between the two holographic writing beams. Thereby, the proposed method can be applicable to wavelength division multiplexing systems. In this study, we demonstrated the mode separation using the proposed demultiplexer with dual-wavelength. The results showed that the separation ratios of three LP modes reached around 90%.

Kawabata, Kento; Okamoto, Atsushi; Honma, Satoshi; Wakayama, Yuta; Sato, Kunihiro; Tomita, Akihisa



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



Volume phase holographic grating performance on the VIRUS-P instrument  

NASA Astrophysics Data System (ADS)

The Visible Integral-field Replicable Unit Spectrograph Prototype (VIRUS-P) has been in operation on the Harlan J Smith 2.7m Telescope at McDonald Observatory since October of 2006. The prototype was created to test the design and science capabilities of the full VIRUS instrument, wherein 150 copies of the spectrograph will be installed on the Hobby Eberly Telescope (HET). We here discuss the specialized test bench built to assess the blue optimized Volume Phase Holographic (VPH) grating performance. We also give lab and on-telescope efficiency measurements for three such gratings in the wavelength range 3400-6800Å. Two sources of stray light relevant to most spectrograph designs are also discussed.

Adams, Joshua J.; Hill, Gary J.; MacQueen, Phillip J.



Performance comparison of equalization/detection schemes for magnification error-dominated volume holographic storage channel  

NASA Astrophysics Data System (ADS)

Data pages retrieved from a volume holographic storage channel (VHSC) suffer from inter-symbol interference (ISI) and noise. Assuming ISI does not change spatially (i.e., stationary), 2-D equalization/detection schemes has been previously developed for quadratic channels like VHSC. In practice, however, the point spread function of a VHSC changes spatially due to magnification and misalignment errors. In this paper, we develop a channel model for magnification error (ME) dominated VHSC and also evaluate the effect of ME on the equalization/detection performance. Results indicate that the recently introduced iterative magnitude-squared decision feedback equalization (IMSDFE) method is more robust to magnification error compared to linear minimum mean squared-error (LMMSE) equalization and adaptive threshold detection (ATD).

Keskinoz, Mehmet; Vijaya Kumar, B. V. K.



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.



Low spatial frequency characterization of holographic recording materials applied to correlation  

NASA Astrophysics Data System (ADS)

Accurate recording of computer-generated holograms (CGH) on a phase material is not a trivial task. The range of available phase materials is large, and their suitability depends on the fabrication technique chosen to produce the hologram. We are particularly interested in low-cost fabrication techniques, easily available for any lab. In this work we present the results obtained with a wide variety of phase holographic recording materials, characterized at low spatial frequencies (leq32 lp mm-1) which is the range associated with the technique we use to produce the CGHs. We have considered bleached emulsion, silver halide sensitized gelatin (SHSG) and dichromated gelatin. Some interesting differences arise between the behaviour of these materials in the usual holographic range (>1000 lp mm-1), and the low-frequency range intended for digital holography. The ultimate goal of this paper is to establish the suitability of different phase materials as the media to generate correlation filters for optical pattern recognition. In all the materials considered, the phase filters generated ensure the discrimination of the target in the recognition process. Taking into account all the experimental results, we can say that SHSG is the best material to generate phase CGHs with low spatial frequencies.

Márquez, A.; Neipp, C.; Beléndez, A.; Campos, J.; Pascual, I.; Yzuel, M. J.; Fimia, A.



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.



Image hiding in Fourier domain by use of joint transform correlator architecture and holographic technique.  


Based on joint transform correlator (JTC) architecture and holographic techniques, a new method for image hiding is presented. A hidden image encrypted by JTC architecture is embedded in the Fourier hologram of the host image. Inverse Fourier transform can be used to obtain the watermarked image, and JTC architecture is used to decode the hidden image from the watermarked hologram. Unlike other watermarking techniques, by prechoosing information, the noise added to the recovered hidden image by the host can be reduced. Unlike other watermarking systems based on double random-phase encoding, no conjugate key is used to recover the hidden image. Theoretical analyses have shown the system's feasibility. Computer simulations are presented to verify the system's validity and efficiency. Numerical simulations also show that the proposed system is robust enough to resist attacks, such as occlusion, noise, and filtering. PMID:21343999

Shi, Xiaoyan; Zhao, Daomu



Diffracted wavefront measurement of a volume phase holographic grating at cryogenic temperature  

SciTech Connect

Flatness of the wavefront diffracted by grating can be mandatory for some applications. At ambient temperature, the wavefront diffracted by a volume phase holographic grating (VPHG) is well mastered by the manufacturing process and can be corrected or shaped by post polishing. However, to be used in cooled infrared spectrometers, VPHGs have to stand and work properly at low temperatures.We present the measurement of the wavefront diffracted by atypical VPHG at various temperatures down to 150 K and at several thermal inhomogeneity amplitudes. The particular grating observed was produced using a dichromated gelatine technique and encapsulated between two glass blanks. Diffracted wavefront measurements show that the wavefront is extremely stable according to the temperature as long as the latter is homogeneous over the grating stack volume. Increasing the thermal inhomogeneity increases the wavefront error that pinpoints the importance of the final instrument thermal design. This concludes the dichromated gelatine VPHG technology, used more and more in visible spectrometers, can be applied as it is to cooled IR spectrometers.

Blanche, Pierre-Alexandre; Habraken, Serge; Lemaire, Philippe; Jamar, Claude



Diffracted wavefront measurement of a volume phase holographic grating at cryogenic temperature.  


Flatness of the wavefront diffracted by grating can be mandatory for some applications. At ambient temperature, the wavefront diffracted by a volume phase holographic grating (VPHG) is well mastered by the manufacturing process and can be corrected or shaped by postpolishing. However, to be used in cooled infrared spectrometers, VPHGs have to stand and work properly at low temperatures. We present the measurement of the wavefront diffracted by a typical VPHG at various temperatures down to 150 K and at several thermal inhomogeneity amplitudes. The particular grating observed was produced using a dichromated gelatine technique and encapsulated between two glass blanks. Diffracted wavefront measurements show that the wavefront is extremely stable according to the temperature as long as the latter is homogeneous over the grating stack volume. Increasing the thermal inhomogeneity increases the wavefront error that pinpoints the importance of the final instrument thermal design. This concludes the dichromated gelatine VPHG technology, used more and more in visible spectrometers, can be applied as it is to cooled IR spectrometers. PMID:16946764

Blanche, Pierre-Alexandre; Habraken, Serge; Lemaire, Philippe; Jamar, Claude



Diffracted wavefront measurement of a volume phase holographic grating at cryogenic temperature  

NASA Astrophysics Data System (ADS)

Flatness of the wavefront diffracted by grating can be mandatory for some applications. At ambient temperature, the wavefront diffracted by a volume phase holographic grating (VPHG) is well mastered by the manufacturing process and can be corrected or shaped by postpolishing. However, to be used in cooled infrared spectrometers, VPHGs have to stand and work properly at low temperatures. We present the measurement of the wavefront diffracted by a typical VPHG at various temperatures down to 150 K and at several thermal inhomogeneity amplitudes. The particular grating observed was produced using a dichromated gelatine technique and encapsulated between two glass blanks. Diffracted wavefront measurements show that the wavefront is extremely stable according to the temperature as long as the latter is homogeneous over the grating stack volume. Increasing the thermal inhomogeneity increases the wavefront error that pinpoints the importance of the final instrument thermal design. This concludes the dichromated gelatine VPHG technology, used more and more in visible spectrometers, can be applied as it is to cooled IR spectrometers.

Blanche, Pierre-Alexandre; Habraken, Serge; Lemaire, Philippe; Jamar, Claude



Photopolymerization kinetics and volume holographic recording in ZrO2 nanoparticle-polymer composites at 404 nm  

NASA Astrophysics Data System (ADS)

We investigate volume holographic recording in a ZrO2 nanoparticle-polymer composite film at a wavelength of 404 nm. Dependences of the polymerization kinetics on concentrations of an initiator and ZrO2 nanoparticles doped in acrylate monomer are examined by using a photodifferential scanning calorimeter. It is found that there exists the optimum concentration of ZrO2 nanoparticles to maximize the polymerization rate. The diffraction and scattering properties of transmission volume gratings are also investigated. It is found that the refractive index modulation and the material recording sensitivity are as high as 8×10-3 and 9000 cm/J, respectively, at the optimum ZrO2 nanoparticle concentration of 35 vol % and at a recording intensity of 5 mW/cm2. These material parameters are larger than typical minimum ones of 5×10-3 and 500 cm/J, respectively, for optimized performance in holographic data storage.

Omura, Koji; Tomita, Yasuo



Design and development of the high-resolution spectrograph HERMES and the unique volume phase holographic gratings  

NASA Astrophysics Data System (ADS)

We report on the grating development for the High Efficiency and Resolution Multi Element Spectrograph (HERMES). This paper discusses the challenges of designing, optimizing, and tolerancing large aperture volume phase holographic (VPH) gratings for HERMES. The high spectral resolution requirements require steep angles of incidence, of 67.2 degrees, and high line densities, ranging between 2400 and 3800 lines per mm, resulting in VPH gratings that are highly s-polarized that push the fabrication process to its limits.

Heijmans, J. A. C.; Gers, L.; Faught, B.



Calculation of the scheme of recording a volume axial holographic optical element in the infrared region of the spectrum  

NASA Astrophysics Data System (ADS)

Main parameters of the scheme of recording a volume axial holographic optical element (HOE) in the infrared region of the spectrum are calculated. The recording scheme is based on a modified scheme of the cyclic Hariharan-Sen interferometer. For the HOE 400 mm in diameter with a focal length of 800 mm, the calculated parameters of the recording scheme are presented that demonstrate that the diameter of the optical element is much less than the HOE diameter.

Batomunkuev, Yu. Ts.; Meshcheryakov, N. A.



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.



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



Silicon oxide nano-particles doped PQ-PMMA for volume holographic imaging filters  

PubMed Central

Holographic imaging filters are required to have high Bragg selectivity to obtain spatial-spectral information within a three-dimensional object. In this Letter, we present the design of holographic imaging filters formed using silicon oxide nano-particles (nano-SiO2) in PQ-PMMA polymer recording material. This combination offers greater angular and spectral selectivity and increases the diffraction efficiency of holographic filters. The holographic filters with optimized ratio of nano-SiO2 in PQ-PMMA can significantly improve the performance of Bragg selectivity and diffraction efficiency by 53% and 16%, respectively. We present experimental results and data analysis demonstrating this technique in use for holographic spatial-spectral imaging filters.

Luo, Yuan; Russo, Juan M.; Kostuk, Raymond K.; Barbastathis, George



Wavelength stabilization of high power laser systems using volume holographic gratings  

NASA Astrophysics Data System (ADS)

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

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



Measurement of throughput variation across a large format volume-phase holographic grating.  


In this paper, we report measurements of diffraction efficiency and angular dispersion for a large format (~ 25 cm diameter) Volume-Phase Holographic (VPH) grating optimized for near-infrared wavelengths (0.9 ~ 1.8 mum). The aim of this experiment is to see whether optical characteristics vary significantly across the grating. We sampled three positions in the grating aperture with a separation of 5 cm between each. A 2 cm diameter beam is used to illuminate the grating. At each position, throughput and diffraction angle were measured at several wavelengths. It is found that whilst the relationship between diffraction angle and wavelength is nearly he same at the three positions, the throughputs vary by up to ~ 10% from position to position. We explore the origin of the throughput variation by comparing the data with predictions from coupled-wave analysis. We find that it can be explained by a combination of small variations over the grating aperture in gelatin depth and/or refractive index modulation amplitude, and amount of energy loss by internal absorption and/or surface reflection. PMID:19495324

Tamura, Naoyuki; Murray, Graham; Sharples, Ray; Robertson, David; Allington-Smith, Jeremy



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



Pulse splitting by modulating the thickness of buffer layer of two-layer volume holographic grating.  


Based on Kogelnik's coupled-wave theory and matrix optics, generation of femtosecond double pulses by modulating thickness of the buffer layer of two-layer volume holographic grating (TL-VHG) is discussed. Expressions of diffraction field when a femtosecond pulse incidents on the TL-VHG are deduced. Simulation results show when thickness of the buffer layer increases from 6mm to 11 mm or even larger, one incident pulse splits into double femtosecond pulses with the same duration and peak intensity, and pulse interval is linearly proportional to the thickness. The reason of these phenomena is due to the interference of diffraction waves reconstructed from two gratings and phase shift resulting from the buffer layer thickness. Time-delay of diffracted double pulses is explained by group time delay of periodic media. It is shown that the slope of the pulse interval with respect to the thickness of buffer layer is 2 times of that of pulse time-delay. Furthermore, we demonstrate it is possible to control the output double pulses' duration and pulse interval by varying the grating thickness. PMID:24514781

Yan, Xiaona; Qian, Mengdi; Gao, Lirun; Yang, Xihua; Dai, Ye; Yan, Xiaoyuan; Ma, Guohong



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



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



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


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



Raman Spectroscopy and Microscopic Raman Imaging with Applications of Volume Holographic Optical Elements.  

NASA Astrophysics Data System (ADS)

Holographic optical elements are crucial for the development of compact and efficient Raman spectroscopic instrumentation. Holographic optics allow direct coupling of a single-stage spectrograph to a Raman microprobe. The high transmission efficiency and narrow rejection-band characteristics of the holographic beam splitter provide efficient use of low power lasers, while allowing acquisition of low-frequency Raman spectra. The holographic notch filter and holographic beamsplitter are essential tools for microscopic Raman imaging. Holographic transmission gratings used in an axial transmissive spectrograph provide high efficiency and low f/n operation. When coupled to a Raman microprobe, this single stage spectrograph can deliver converter-limited Raman signal in seconds. The capability of a matched-pair of holographic transmission gratings was explored as a filter device for Raman imaging. Without optimization, transmission efficiencies of 70% were observed throughout the visible light region and band passes of about 300 cm^{-1 }. This filter device allowed microscopic imaging of samples using isolated Raman bands or fluorescence signal. The echo in transformed images from the Hadamard transform Raman imaging microscope were found to originate from diffraction of light from the Hadamard mask and thermal instability of the optical system. Instabilities of the on-board CCD detector amplifier was shown to be a source of flicker noise. The depth of field characteristics of the Hadamard transform Raman microscope were experimentally determined. A universal illumination method was demonstrated for filter-based Raman imaging. The effects of coherent illumination and quasi-incoherent illumination on microscopic Raman image resolution is experimentally demonstrated. The illumination methods developed in this work improved the quality of our Raman imaging and were crucial to the success of digital confocal Raman imaging. Applications were developed which demonstrate the benefits of the digital confocal Raman microscopy. Digital confocal image restoration techniques and extended field visualization of 3D Raman images were demonstrated.

Pallister, David Mark


Rewritable holographic memory card system  

Microsoft Academic Search

The new rewritable holographic memory card (HMC) of Optilink provides a novel solution for high density optical storage of personal data. In contrast to most holographic storage systems using highly multiplexed transmissive volume holograms in bulk materials, our approach is adapted to the card format using a polymer thin film holographic storage material, operating in reflection mode, allowing writing and

E. Lorincz; P. Koppa; F. Ujhelyi; P. I. Richter; G. Szarvas; Gabor Erdei; P. S. Ramanujam



Comparative evaluation of the volume holographic memory information capacity limits caused by different limitation factors  

NASA Astrophysics Data System (ADS)

The possibility to use the third dimension of the medium for data storage and extraction in memory devices is accessible in a wide sense only if a holographic method of data recording and reconstruction is used. However, this possibility has many limitations part of which is inherent just to the holographic devices. Among them one can find significant influence of a limited dynamic range, quadratic dependence of power expenses on the amount of stored information, limitations of the number of selective positions which can be used for the hologram multiplexing as well as some geometric limitations which are significant in 3-D holographic memory. On a level with that, such phenomena exercise influence on holographic memory device information capability as diffraction limits of information input and storage, spatial information losses in a complex system, limitations of rate of information input and output in holographic memory devices etc. The limitations caused by each of the listed factors have been compared and analyzed. It has been found that some of these factors do not influence on information capability limitations provided by the other reasons.

Gurevich, Boris S.; Gurevich, Simon B.; Zhumaliev, Kubanychbek M.; Alymkulov, Salmor A.; Sagymbaev, Samat A.; Akkoziev, Imil A.



Real-time signal classification with an acousto-optic triple-product processor cascaded into a volume holographic classifier  

NASA Astrophysics Data System (ADS)

An all-optical generalized linear machine applied to a high-bandwidth temporal signal-classification problem is demonstrated. The classifier consists of a dimensional increasing acousto-optic triple-product processor feature extractor cascaded through an optically addressed spatial light modulator into a volume holographic implementation of a linear classifier. Multiple-exposure implementations of learning are used to train the classifier interconnection weights in a photorefractive crystal for a training set of wide-bandwidth temporal signals input to the acousto-optic triple-product processor. Experimental implementation of high-speed, time-shift and Doppler invariant, wide-bandwidth signal identification is demonstrated.

Garvin, Charles; Wagner, Kelvin



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

NASA Technical Reports Server (NTRS)

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

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



Using volume holograms to search digital databases  

Microsoft Academic Search

Holographic data storage ofiers the potential for simultaneous search of an entire database by performing multiple optical correlations between stored data pages and a search argument (1, 2). This content{addressable retrieval produces one analog correlation score for each stored volume hologram. We have previously developed fuzzy encoding techniques for this fast parallel search, and holographically searched a small database with

Geofirey W. Burr; George Maltezos; Felix Grawert; Sebastian Kobras; Holger Hanssen; Hans Coufal



Dichromated gelatin for volume holographic recording with high sensitivity. Part I  

Microsoft Academic Search

Dichromated gelatin would be the most suitable irreversible medium for holographic recording but for its low sensitivity. The efficiency of the photoinduced reduction of the chromium ion increases considerably if superfine grains of silver halide crystals are present in the layer. The light sensitivity achieved is about 10 times better than that of dichromated gelatin layers, obtained and processed in

M. Mazakova; M. Pancheva; P. Kandilarov; P. Sharlandjiev



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


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



Study on very high speed Reed-Solomon decoders using modified euclidean algorithm 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 protect digital data against errors. This paper presents VLSI implementations of an 16 errors correcting (255,223) Reed-Solomon decoder architecture for volume holographic storage. We describe the Reed-Solomon decoders using modified Euclidean algorithms which are regular and simple, and naturally suitable for VLSI implementations. We design the speedily multiplication for GF(28) and pipeline structure to solve hardware complexity and high data processing rate for the Reed-Solomon decoders. We adopt high speed FPGA and have a data processing rate of 200 Mbit/s.

Wu, Fei; Xie, Changsheng; Liu, ZhaoBin



Fixed delay tree-search based detection for volume holographic data storage  

NASA Astrophysics Data System (ADS)

As densities of storage increase in holographic optical memories, ISI becomes an issue calling for efficient equalization techniques. We investigate the use of fixed delay tree-search (FDTS) as an economical alternative to the optimal but often complex solution of maximum likelihood sequence detection. We compare the two techniques from a performance and complexity perspective and show that the former is simpler to implement with limited loss in performance. We adapt fixed-delay tree search with partial response equalization to holographic storage and quantify SNR and density gains obtained from it. The benefit of low- pass codes used with FDTS is also investigated. A cumulative density improvement of 71% is shown to be feasible using FDTS for scatter-limited channels.

Vadde, Venkatesh; Vijaya Kumar, B. V. K.



Volume holographic grating couplers: rigorous analysis by use of the finite-difference frequency-domain method  

NASA Astrophysics Data System (ADS)

Two configurations of volume holographic grating couplers are rigorously analyzed by means of the finite-difference frequency-domain method (FDFD) for both TE and TM polarizations and for 0- and 45-deg output coupling. The two configurations depend on the position of the grating coupler, which can be placed either in the film or in the cover waveguide region. The FDFD results are compared with those obtained by the rigorous coupled-wave analysis in conjunction with the leaky-mode approach (RCWA-LM). Because the FDFD method is a rigorous solution of the Maxwell equations, it simulates the VHGC configuration and takes into account the waveguide-coupler discontinuity effects as well as the multimode excitation and interference effects, all of which are neglected by the traditional RCWA-LM.

Wu, Shun-Der; Glytsis, Elias N.



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


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



Ultra-low frequency Stokes and anti-Stokes Raman spectroscopy at 785nm with volume holographic grating filters  

NASA Astrophysics Data System (ADS)

We report the first results of ultra-low frequency Stokes and anti-Stokes Raman spectra at 785nm showing clearly resolved frequency shifts down to 10cm-1 from the excitation line, using commercially available ultra-narrow band notch and ASE suppression filters, and a single stage spectrometer. Near infra-red (NIR) wavelengths are of particular interest for Raman spectroscopy due to the reduced fluorescence observed for most materials. Previously reported attempts to produce ultra-low frequency Raman spectra at 785nm with volume holographic notch filters were largely unsuccessful, due to the fact that these ultra-narrow line notch filters and the wavelength of the laser must be very well matched to be effective. Otherwise, if the filters have any manufacturing errors or the laser wavelength is unstable, insufficient suppression of the Rayleigh scattered light will allow it to overwhelm the Raman signal. Recent improvements in both notch and ASE filters, wavelength-stabilized lasers, and optical system design have enabled low-frequency Raman spectra to be successfully taken at 785nm for several typical materials. Two ultra-narrow line notch filters formed as volume holographic gratings (VHGs) in glass with individually measured optical densities of 4.5 were used to block the Rayleigh scattered light from a matched VHG wavelength stabilized laser. Five discrete peaks below 100cm-1 were simultaneously observed for sulfur in both the Stokes and anti-Stokes regions at 28, 44, 52, 62, and 83cm-1. With no degradation in filter performance over time and extremely narrow spectral transition widths of less than 10cm-1, this relatively simple system is able to make ultra-low frequency Stokes and anti-Stokes Raman measurements at a fraction of the size and cost of traditional triple monochromator systems.

Carriere, James T.; Havermeyer, Frank



Holographic Signature Processor.  

National Technical Information Service (NTIS)

In the patent application a signature is holographically recorded for correlation and parallel processing against a large library of signatures. A transient electrical signal produces a pressure wave in an optical wavefront modulator where it is frozen in...

H. L. Simpson



Real-time optical correlator using computer-generated holographic filter on a liquid crystal light valve  

NASA Technical Reports Server (NTRS)

Limitations associated with the binary phase-only filter often used in optical correlators are presently circumvented in the writing of complex-valued data on a gray-scale spatial light modulator through the use of a computer-generated hologram (CGH) algorithm. The CGH encodes complex-valued data into nonnegative real CGH data in such a way that it may be encoded in any of the available gray-scale spatial light modulators. A CdS liquid-crystal light valve is used for the complex-valued CGH encoding; computer simulations and experimental results are compared, and the use of such a CGH filter as the synapse hologram in a holographic optical neural net is discussed.

Chao, Tien-Hsin; Yu, Jeffrey



Application of three-dimensional spatial correlation properties of coherent noise in phase noise suppression for digital holographic microscopy  

NASA Astrophysics Data System (ADS)

The inherited coherent noise degrades the phase imaging quality in digital holographic microscopy (DHM). To overcome the problem, an experimental investigation on the three-dimensional (3D) spatial correlation properties of coherent noise is carried out. Multiple blank holograms are recorded without any specimen in DHM setup by consecutively shifting camera along the optical axis, and a series of phase distribution of coherent noise can be obtained by numerical reconstruction. Then, based on the phase distributions, the lateral and longitudinal correlation properties of coherent noise are analyzed by a discrete correlation algorithm. Furthermore, a method for reducing phase noise is proposed by use of multiple holograms. Firstly, a series of holograms are recorded by shifting the camera longitudinally with the step more than longitudinal correlation length of coherent noise field. Secondly, the reconstruction of the holograms leads to a series of phase images of object, in which the coherent noise has different patterns. Consequently, by averaging the phase images, the reductions of phase noise are achieved. The applicability of the method is demonstrated by imaging of the resolution targets and the grating.

Pan, Feng; Xiao, Wen; Liu, Shuo; Rong, Lu



Volume-phase holographic gratings and their potential for astronomical applications  

Microsoft Academic Search

A diffraction grating technology based upon volume-phase holograms shows promise of enhanced performance for many applications in astronomical spectroscopy over classical surface-relief grating technology. We present a discussion of the underlying physics of a volume-phase grating, give some theoretical performance characteristics, present performance data for a real volume-phase grating, and discuss some potential applications for this grating technology.

Samuel C. Barden; James A. Arns; Willis S. Colburn



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


Numerical simulation of diffraction on thick holographic gratings in shift-multiplexed optical data storage application is presented. The grating is generated by the interference of a spherical reference wave and a plane signal wave corresponding to a single pixel of the input data page. To describe diffraction on this weak-index-modulated grating, we use the volume integral equation in the first Born approximation. This description yields a convolution integral that can be efficiently evaluated by a 3D fast Fourier transform (FFT) technique. For a 51.2 microm recording layer thickness, a serial-divided single personal computer code was built based on parallel FFT coding principles. Diffracted electric field and Poynting-vector distributions are calculated for probe beams spatially shifted with respect to the reference beams. The shift selectivity curves show significant differences from previous analytical calculations based on paraxial propagation and infinite gratings, as they have monotonic decrease in all three directions instead of sinclike functions with Bragg nulls. With the chosen numerical aperture of 0.6 and linear polarization, both the scalar and vector calculations provided similar results within 5%. PMID:17047723

Gombköto, Balázs; Koppa, Pál; Maák, Pál; Lorincz, Emoke



Anatomical and functional correlates of human hippocampal volume asymmetry  

PubMed Central

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

Woolard, Austin; Heckers, Stephan



Development of volume phase holographic (VPH) grism for visible to near infrared instruments of 8.2m Subaru Telescope  

NASA Astrophysics Data System (ADS)

Faint Object Camera and Spectrograph (FOCAS) is a versatile open use optical instrument of the 8.2m Subaru Telescope for the enabling imaging and spectroscopic observations. A suite of nine grisms optimized for different resolving powers and appropriate wavelength ranges have been planned for this instrument. Five grisms among the nine were fabricated by a replication method and four additional grisms with the resolving power of 5,000 are under fabrication using the volume phase holographic (VPH) gratings. A very high dispersion Echelle grism with the resolving power over 10,000 is also developing with a VPH grating sandwiched between two high index prisms. The high dispersion VPH grisms are 110 by 106 mm in aperture size and 110 mm in maximum thickness. We employed a photosensitive resin as the recording material for a thick VPH grating. In the present paper, we report the result of evaluation of the diffraction efficiency of the replica grisms and the VPH gratings by means of the rigorous coupled-wave analysis (RCWA) method to derive the optimum design parameters. An optimized VPH grating with a size of 50 by 50 mm was experimentally fabricated by means of a two-wave interference exposure at 532nm. The measured diffraction efficiency of this VPH grating is 88% at 400nm. We performed spectroscopic observations of Leonid meteors by using an image intensified CCD video camera and an experimentally fabricated VPH grism as an objective dispersion element at Nobeyama, National Astronomical Observatory of Japan in November, 2001. Consequently, we successfully obtained numerous high-quality spectroscopic data of meteors.

Ebizuka, Noboru; Oka, Keiko; Yamada, Akiko; Watanabe, Mami; Shimizu, Kayo; Kodate, Kashiko; Kawabata, Masami; Teranishi, Takashi; Kawabata, Koji S.; Iye, Masanori



Holographic real-time nonrelativistic correlators at zero and finite temperature  

NASA Astrophysics Data System (ADS)

We compute a variety of two and three-point real-time correlation functions for a strongly-coupled nonrelativistic field theory. We focus on the theory conjectured to be dual to the Schrödinger-invariant gravitational spacetime introduced by Balasubramanian, McGreevy, and Son, but our methods apply to a large class of nonrelativistic theories. At zero temperature, we obtain time-ordered, retarded, and Wightman nonrelativistic correlators for scalar operators of arbitrary conformal dimension directly in field theory by applying a certain lightlike Fourier-transform to relativistic conformal correlators, and we verify that nonrelativistic AdS/CFT reproduces the results. We compute thermal two and three-point real-time correlators for scalar operators dual to scalar fields in the black hole background which is the finite-temperature generalization of the Schrödinger spacetime. This is done by first identifying thermal real-time bulk-to-boundary propagators which, when combined with Veltman’s circling rules, yield two and three-point correlators. The two-point correlators we obtain satisfy the Kallen-Lehmann relations. We also give retarded and time-ordered three-point correlators.

Barnes, Edwin; Vaman, Diana; Wu, Chaolun



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

NASA Astrophysics Data System (ADS)

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

Watanabe, Eriko; Ikeda, Kanami; Kodate, Kashiko



Resolution enhancement of holographic printer using a hogel overlapping method.  


We propose a hogel overlapping method for the holographic printer to enhance the lateral resolution of holographic stereograms. The hogel size is directly related to the lateral resolution of the holographic stereogram. Our analysis by computer simulation shows that there is a limit to decreasing the hogel size while printing holographic stereograms. Instead of reducing the size of hogel, the lateral resolution of holographic stereograms can be enhanced by printing overlapped hogels, which makes it possible to take advantage of multiplexing property of the volume hologram. We built a holographic printer, and recorded two holographic stereograms using the conventional and proposed overlapping methods. The images and movies of the holographic stereograms experimentally captured were compared between the conventional and proposed methods. The experimental results confirm that the proposed hogel overlapping method improves the lateral resolution of holographic stereograms compared to the conventional holographic printing method. PMID:23787594

Hong, Keehoon; Park, Soon-gi; Yeom, Jiwoon; Kim, Jonghyun; Chen, Ni; Pyun, Kyungsuk; Choi, Chilsung; Kim, Sunil; An, Jungkwuen; Lee, Hong-Seok; Chung, U-in; Lee, Byoungho



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.



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


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. PMID:23487181

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



Holographic sundial.  


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

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



Holographic technidilaton  

SciTech Connect

Technidilaton, a pseudo-Nambu-Goldstone boson of scale symmetry, was predicted long ago in the scale-invariant/walking/conformal technicolor (SWC-TC) as a remnant of the (approximate) scale symmetry associated with the conformal fixed point, based on the conformal gauge dynamics of ladder Schwinger-Dyson (SD) equation with nonrunning coupling. We study the technidilaton as a flavor-singlet bound state of technifermions by including the technigluon condensate (tGC) effect into the previous (bottom-up) holographic approach to the SWC-TC, a deformation of the holographic QCD with {gamma}{sub m{approx_equal}}0 by large anomalous dimension {gamma}{sub m{approx_equal}}1. With including a bulk scalar field corresponding to the gluon condensate, we first improve the operator product expansion of the current correlators so as to reproduce gluonic 1/Q{sup 4} term both in QCD and SWC-TC. We find in QCD about 10% (negative) contribution of gluon condensate to the {rho} meson mass. We also calculate the oblique electroweak S-parameter in the presence of the effect of the tGC and find that for the fixed value of S the tGC effects dramatically reduce the flavor-singlet scalar (technidilaton) mass M{sub TD} (in the unit of F{sub {pi}}), while the vector and axial-vector masses M{sub {rho}}and M{sub a{sub 1}} are rather insensitive to the tGC, where F{sub {pi}}is the decay constant of the technipion. If we use the range of values of tGC implied by the ladder SD analysis of the nonperturbative scale anomaly in the large N{sub f} QCD near the conformal window, the phenomenological constraint S{approx_equal}0.1 predicts the technidilaton mass M{sub TD{approx}}600 GeV which is within reach of LHC discovery.

Haba, Kazumoto [Department of Physics, Nagoya University, Nagoya, 464-8602 (Japan); Matsuzaki, Shinya [Department of Physics, Pusan National University, Busan 609-735 (Korea, Republic of); Yamawaki, Koichi [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University, Nagoya 464-8602 (Japan)



Fabrication of Near-Infrared Volume Phase Holographic Grism with High Efficiency and High Dispersion, and Its Application to a Wavelength De-multiplexing Device  

NASA Astrophysics Data System (ADS)

We designed and developed a volume phase holographic (VPH) grism with high resolution and high efficiency in the near-infrared light domain (1550 nm) to be applied as a wavelength de-multiplexing device of a photonic network. In order to achieve both diffraction efficiency of over 80% and wavelength resolution of 0.08 nm, we newly designed and fabricated a VPH grism with high efficiency and high wavelength resolution in near-infrared wavelength region by sandwiching a VPH grating between prisms. An active feedback control technique was introduced to a two-beam interference exposure system, and we also applied it to a wavelength de-multiplexing device for a photonic network. Consequently, a VPH grism was successfully fabricated with diffraction efficiency of over 80% by employing the Bragg condition of 1550 nm at the incident wavelength from 1530 to 1570 nm, and high refractive index modulation of 0.047 was confirmed.

Nakajima, Kaoru; Komai, Yuki; Watanabe, Eriko; Moritsuka, Fumi; Anzai, Shimako; Kodate, Kashiko



Flat optical lens by use of 90-degree volume holographic grating recording geometry and nonvolatile thermal fixing in LiNbO3:Fe crystal  

NASA Astrophysics Data System (ADS)

A new design and fabrication of flat optical lens by use of 90-degree volume holographic grating recording geometry is presented. It is recorded by the interference of a plane wave and a spherical wave in a Fe-doped LiNbO3. The flat optical lens can laterally transfer and focus the plane wave which perpendicularly incidents on the planar crystal surface. The optimal switching from recording to thermal fixing is taken into consideration in order to obtain the nonvolatile hologram with maximum fixing efficiency. The flat optical lens with different recording and reconstructing wavelength has also been discussed. The flat optical lens has the advantages of light weight, laterally transferring and focusing, small duty ratio, and easy for the microstructure integration. The testing results measured verify that the flat optical lens can successfully be used for the free space optical communication.

Zhi, Ya'nan; Chai, Zhifang; Zhu, Yongjian; Hou, Peipei; Sun, Jianfeng; Zhou, Yu; Liu, Liren



Holographic pomeron  

NASA Astrophysics Data System (ADS)

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

Stoffers, Alexander


Effects of pore volume-transmissivity correlation on transport phenomena  

NASA Astrophysics Data System (ADS)

The relevant velocity that describes transport phenomena in a porous medium is the pore velocity. For this reason, one needs not only to describe the variability of transmissivity, which fully determines the Darcy velocity field for given source terms and boundary conditions, but also any variability of the pore volume. We demonstrate that hydraulically equivalent media with exactly the same transmissivity field can produce dramatic differences in the displacement of a solute if they have different pore volume distributions. In particular, we demonstrate that correlation between pore volume and transmissivity leads to a much smoother and more homogeneous solute distribution. This was observed in a laboratory experiment performed in artificial fractures made of two plexiglass plates into which a space-dependent aperture distribution was milled. Using visualization by a light transmission technique, we observe that the solute behaviour is much smoother and more regular after the fractures are filled with glass powder, which plays the role of a homogeneous fault gouge material. This is due to a perfect correlation between pore volume and transmissivity that causes pore velocity to be not directly dependent on the transmissivity, but only indirectly through the hydraulic gradient, which is a much smoother function due to the diffusive behaviour of the flow equation acting as a filter. This smoothing property of the pore volume-transmissivity correlation is also supported by numerical simulations of tracer tests in a dipole flow field. Three different conceptual models are used: an empty fracture, a rough-walled fracture filled with a homogeneous material and a parallel-plate fracture with a heterogeneous fault gouge. All three models are hydraulically equivalent, yet they have a different pore volume distribution. Even if piezometric heads and specific flow rates are exactly the same at any point of the domain, the transport process differs dramatically. These differences make it important to discriminate in situ among different conceptual models in order to simulate correctly the transport phenomena. For this reason, we study the solute breakthrough and recovery curves at the extraction wells. Our numerical case studies show that discrimination on the basis of such data might be impossible except under very favourable conditions, i.e. the integral scale of the transmissivity field has to be known and small compared to the dipole size. If the latter conditions are satisfied, discrimination between the rough-walled fracture filled with a homogeneous material and the other two models becomes possible, whereas the parallel-plate fracture with a heterogeneous fault gouge and the empty fracture still show identifiability problems. The latter may be solved by inspection of aperture and pressure testing.

Lunati, Ivan; Kinzelbach, Wolfgang; Sørensen, Ivan



A robust cell counting approach based on a normalized 2D cross-correlation scheme for in-line holographic images.  


To achieve the important aims of identifying and marking disease progression, cell counting is crucial for various biological and medical procedures, especially in a Point-Of-Care (POC) setting. In contrast to the conventional manual method of counting cells, a software-based approach provides improved reliability, faster speeds, and greater ease of use. We present a novel software-based approach to count in-line holographic cell images using the calculation of a normalized 2D cross-correlation. This enables fast, computationally-efficient pattern matching between a set of cell library images and the test image. Our evaluation results show that the proposed system is capable of quickly counting cells whilst reliably and accurately following human counting capability. Our novel approach is 5760 times faster than manual counting and provides at least 68% improved accuracy compared to other image processing algorithms. PMID:23839256

Ra, Ho-Kyeong; Kim, Hyungseok; Yoon, Hee Jung; Son, Sang Hyuk; Park, Taejoon; Moon, Sangjun



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


Application of holographic particle image velocimetry in bubbly flow  

NASA Astrophysics Data System (ADS)

Measuring the velocity field of a bubbly flow is of major importance in many industrial applications like, bubble column reactors. Traditional PIV setup is limited to single plane measurements. The present study involved extension of the existing holographic PIV method to two-phase flow velocimetry. The objective of the present study was to conduct velocity measurements using in-line holographic microscopy arrangement to analyze a flow consisting of an air bubble rising through stagnant water in a rectangular column. Neutrally buoyant 8 microm sized hollow glass spheres are scattered uniformly in the continuous phase and are used as seed particles for image analysis. Double-pulsed hologram is taken with a 2K by 2K pixels CCD sensor with 200micros in between the two frames, which allows only a small movement of both the particles (in the continuous phase) and that of the dispersed phase itself. Holograms are reconstructed at different distances to produce images at every millimeter of the measurement volume. An averaging technique is developed to process the images to reduce the noise in reconstructed holographic images and make it useful for cross-correlation analysis. The image pairs are cross correlated and velocity vectors are obtained for the continuous phase. The dispersed phase velocity is measured using the shift in the center of the bubble. After analyses of all the image pairs throughout the measurement volume, a two component three dimensional velocity field is produced for the two-phase flow.

Banerjee, Atanu


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



Fast fluorescence holographic microscopy  

NASA Astrophysics Data System (ADS)

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

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



Tuning Ion Conducting Pathways Using Holographic Polymerization  

NASA Astrophysics Data System (ADS)

While much research has demonstrated repeatable characteristics of electrolyte membranes, the fundamentals behind the interactions during ionic diffusion in solid polymer electrolyte membranes for battery applications are not well understood, specifically the role of nanostructures, which hold the key to improving performance of energy storage devices such as fuel cells and Lithium ion batteries. The challenges in fabricating highly controlled model systems are largely responsible for the interdependent ambiguities between nanostructures and the corresponding ion conducting behavior. In this work, Holographic Polymer Electrolyte Membranes (hPEM) volume gratings comprised of alternating layers of crosslinked polymer resin and lithium ion salt were fabricated using holographic polymerization with an average d-spacing of approximately 200 nm. These one-dimensional confinement structures were used to quantitatively study the anisotropic ionic conductivity between the directions of in-plane and normal to the layers, and the unique ion conducting behavior was correlated with nanoscale phase separation. These volume gratings also offer an exciting route to fabricate multifunctional gratings for optic and sensing applications.

Smith, Derrick; Li, Christopher; Dong, Bin; Bunning, Timothy



Holographic Optical Data Storage  

NASA Technical Reports Server (NTRS)

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

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



Holographic turbulence.  


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

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



Holographic Turbulence  

NASA Astrophysics Data System (ADS)

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

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



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.



Holographic Graphene  

NASA Astrophysics Data System (ADS)

An appropriately oriented D3-D7-brane system is the holographic dual of relativistic Fermions occupying a 2+1-dimensional defect embedded in 3+1-dimensional spacetime. The Fermions interact via fields of N=4 Yang-Mills theory in the 3+1-dimensional bulk. Recently, using internal flux to stabilize the system in the probe N7<holographic techniques to study perturbations of a particular one of the conformal field theories by relevant operators. Generally, the response of a conformal field theory to such a perturbation grows and becomes nonperturbative at low energy scales. We shall find that a perturbation which switches on a background magnetic field B and Fermion mass m induces a renormalization group flow that can be studied perturbatively in the limit of small m^2/B. We solve the leading order explicitly. We find that, for one particular value of internal flux, the system exhibits magnetic catalysis, the spontaneous breaking of chiral symmetry enhanced by the presence of the magnetic field.

Omid, Hamid; Semenoff, Gordon



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



Hybrid holographic non-destructive test system  

NASA Technical Reports Server (NTRS)

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

Kurtz, R. L. (inventor)



Light-in-flight holography with switched reference beams for cross-correlation in deep volume PIV  

Microsoft Academic Search

We present a holographic PIV system which extends the standard PIV analysis scheme of two velocity components (2D2C) to the third dimension and overcomes the disturbing background light in deep volume images reconstructed from particle holograms. In a light-in-flight holography (LiFH) setup the short coherence length of a modified laser source is used to suppress light from out-of-focus regions. The

S. F. Herrmann; M. Geiger; K. D. Hinsch; J. Peinke


Silver halide sensitized gelatin as a holographic recording material  

NASA Astrophysics Data System (ADS)

Silver halide sensitized gelatin (SHSG) has proven to be a good alternative to dichromated gelatin and bleached emulsions in the production of volume phase holographic optical elements. In the present paper, the processing procedure for SHSG derived from Agfa-Gevaert holographic plates is reviewed and the holographic characteristics of the processed SHSG are experimentally measured and analysed. Several important aspects related to the influence of the developer and the bleach bath, the noise, the diffraction efficiency, the modulation transfer function and the optimized procedure have been considered. Both transmission and reflection holographic gratings and diffuse-object holograms are described in detail.

Fimia, A.; Pascual, I.; Beléndez, A.



Holographic 3-D printer  

Microsoft Academic Search

This paper proposes a holographic printer, which produces 3-D hard copies of computer processed objects. For the purpose of automatic making of 3-D hard copies of distortion free, a new method to synthesize holographic stereogram is proposed. It is is flat format and lippmann type holographic stereogram which can be printed by one optical step. The proposed hologram has not

Masahiro Yamaguchi; Nagaaki Ohyama; Toshio Honda



Wideband millimeter-wave holographic weapons surveillance systems  

Microsoft Academic Search

A new wideband millimeter wave holographic imaging technqiue is under developement for use in concealed weapons detection system. This new wideband technique provides far superior images than single frequency holographic techniques on thick objects such as the human body. The wideband technique obtains fully focused images over a designated volume and provides excellent lateral and depth resolution. Using this method,

Douglas L. McMakin; David M. Sheen; H. D. Collins; Thomas E. Hall; Ronald H. Severtsen



Air impurity in holographic photonic crystals made with dichromated gelatin  

NASA Astrophysics Data System (ADS)

The physical mechanism of the air impurity in volume holographic photonic crystals was investigated in this paper. The photonic forbidden band with the air impurity was analyzed and calculated by the transfer matrix method. Verifications were carried out using one dimensional holographic photonic crystals made with Dichromated Gelatin (DCG), and the impurity modes were observed.

Ren, Zhi; Li, Songtao; Liu, Dahe



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



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)



Sex differences in the correlation of emotional control and amygdala volumes in adolescents.  


We examined male and female adolescents (8-18 years of age) that were scanned with structural brain MRI and looked for a correlation between volume of the right or the left amygdala and parent-reported ability of emotional control. A sex difference was found in the correlation between emotional control and the corrected volume of the left amygdala (that is the amygdala volume adjusted for total cranial volume). In girls, smaller left amygdala volumes were associated with better emotional control. In boys, larger left amygdala volumes were associated with better emotional control. These findings suggest that healthy girls and boys show a difference in the correlation between parental reports of emotional control and the left amygdala volume. PMID:20729768

Blanton, Rebecca E; Chaplin, Tara M; Sinha, Rajita



Sex differences in the correlation of emotional control and amygdala volumes in adolescents  

PubMed Central

We examined male and female adolescents (8–18 years of age) that were scanned with structural brain MRI and looked for a correlation between volume of the right or the left amygdala and parent-reported ability of emotional control. A sex difference was found in the correlation between emotional control and the corrected volume of the left amygdala (that is the amygdala volume adjusted for total cranial volume). In girls, smaller left amygdala volumes were associated with better emotional control. In boys, larger left amygdala volumes were associated with better emotional control. These findings suggest that healthy girls and boys show a difference in the correlation between parental reports of emotional control and the left amygdala volume.

Blanton, Rebecca E.; Chaplin, Tara M.; Sinha, Rajita



Holographic duality in nonlinear hyperbolic metamaterials  

NASA Astrophysics Data System (ADS)

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.

Smolyaninov, Igor I.



Preterm Infant Hippocampal Volumes Correlate with Later Working Memory Deficits  

ERIC Educational Resources Information Center

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

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



Compact, integrateddynamic holographic memory with refreshed holograms  

Microsoft Academic Search

An innovative architecture for compact, integrated volume holographic memories is described. It is based on phase-conjugate readout and on a modulator -detector - memory array implemented in a silicon integrated circuit. The lensless memory module sustains dynamic read-write holograms by periodic refreshing. The integrated circuit is described and experimentally characterized. Holograms were stored in a prototype storage module that uses

Jean-Jacques P. Drolet; Ernest Chuang; George Barbastathis; Demetri Psaltis



Wavelength techniques for digital holographic memories  

NASA Astrophysics Data System (ADS)

Holographic storage is a technique to store and retrieve information spread out in a volume, in contrast to current optical devices which store information locally on a surface. It provides for parallel page-by-page recording and readout of data instead of the usual serial, bit-by-bit, technique, and offers much higher diffraction-limited capacity. Success in the development of a competitive holographic storage device then depends on its cost, compactness and reliability. Since the first digital demonstrations, considerable effort by various groups has been spent in the development of high performance, practical holographic systems. This thesis presents several contributions toward this goal, suitable for holographic storage in lithium niobate and other applicable media. An intuitive explanation of volume holography is given, and Fourier analysis is used to derive the diffraction- limited capacity of digital storage in the form of elementary refractive index gratings. The physics of photorefractive materials, which are commonly used in holographic recording, is then presented, along with an established phenomenological model for grating formation. Following an analysis of imaging and multiplexing, a completely automated storage system implementing wavelength-multiplexed holography is described and evaluated, highlighting the feasibility of systems with fewer optical and mechanical components. The volatility of information in photorefractive media is then addressed by a demonstration of optical fixing, a technique based on two-photon recording mechanisms. Such an all-optical technique removes the need for heating elements, high voltages, or other post-processing elements currently used in non-volatile systems. Two-photon recording is also used to modulate, or apodize, the amplitude of volume gratings within the crystal bulk, providing a flexible technique to reduce cross-talk noise between stored pages and optimize the system capacity. Finally, simulations of apodized cross-talk and overall theoretical and technical capacity limits are given. A proposed holographic disk system, based on the techniques and estimates presented in this thesis while competitive with current storage technologies, is then described.

Lande, David


Focal Volume Optics and Experimental Artifacts in Confocal Fluorescence Correlation Spectroscopy  

Microsoft Academic Search

Fluorescence correlation spectroscopy (FCS) can provide a wealth of information about biological and chemical systems on a broad range of time scales (<1?s to >1s). Numerical modeling of the FCS observation volume combined with measurements has revealed, however, that the standard assumption of a three-dimensional Gaussian FCS observation volume is not a valid approximation under many common measurement conditions. As

Samuel T. Hess; Watt W. Webb



Riboflavin Sensitized Photopolymer Materials for Holographic Storage  

NASA Astrophysics Data System (ADS)

Riboflavin is employed as the photosensitizer of a novel photopolymer material for holographic recording. This material has a broad absorption spectrum range (more than 200 nm) due to the addition of this dye. The experimental results show that our material has high diffraction efficiency and large refractive index modulation. The maximum diffraction efficiency of the photopolymer is about 56%. The digital data pages are stored in this medium and the reconstructed data page has a good fidelity, with the bit-error-ratio of about 1.8×10-4. It is found that the photopolymer material is suitable for high-density volume holographic digital storage.

Zhai, Feng-Xiao; Wang, Ai-Rong; Yin, Qiong; Liu, Jun-Hui; Huang, Ming-Ju



Holographic navigation  

Microsoft Academic Search

This paper presents a method for navigating relative to the sea floor using sonar imagery. The aspect dependent terrain recognition problem is addressed by generating acoustic holograms of the sea floor containing images of all aspects of interest. Grazing angle compensation is applied to reduce the required spatial sampling from planar to linear. Sonar images are coherently correlated with centimeter

Richard J. Rikoski; Daniel C. Brown



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



Ovarian Volume Correlates Strongly with the Number of Nongrowing Follicles in the Human Ovary  

PubMed Central

A reliable indirect measure of ovarian reserve for the individual woman remains a challenge for reproductive specialists. Using descriptive statistics from a large-scale study of ovarian volumes, we have developed a normative model for healthy females for ages 25 through 85. For average values, this model has a strong and positive correlation (r = 0.89) with our recent model of nongrowing follicles (NGFs) in the human ovary for ages 25 through 51. When both models are log-adjusted, the correlation increases to r = 0.99, over the full range of ovarian volume. Furthermore we can deduce that an ovary of 3?cm3 volume (or less) contains approximately 1000?NGF (or fewer). These strong correlations indicate that ovarian volume is a useful factor in the indirect estimation of human ovarian reserve for the individual woman.

Kelsey, Thomas W.; Wallace, W. Hamish B.



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.

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



Physical exercise habits correlate with gray matter volume of the hippocampus in healthy adult humans.  


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



Neuroanatomical Correlates of Intelligence in Healthy Young Adults: The Role of Basal Ganglia Volume  

PubMed Central

Background In neuropsychiatric diseases with basal ganglia involvement, higher cognitive functions are often impaired. In this exploratory study, we examined healthy young adults to gain detailed insight into the relationship between basal ganglia volume and cognitive abilities under non-pathological conditions. Methodology/Principal Findings We investigated 137 healthy adults that were between the ages of 21 and 35 years with similar educational backgrounds. Magnetic resonance imaging (MRI) was performed, and volumes of basal ganglia nuclei in both hemispheres were calculated using FreeSurfer software. The cognitive assessment consisted of verbal, numeric and figural aspects of intelligence for either the fluid or the crystallised intelligence factor using the intelligence test Intelligenz-Struktur-Test (I-S-T 2000 R). Our data revealed significant correlations of the caudate nucleus and pallidum volumes with figural and numeric aspects of intelligence, but not with verbal intelligence. Interestingly, figural intelligence associations were dependent on sex and intelligence factor; in females, the pallidum volumes were correlated with crystallised figural intelligence (r?=?0.372, p?=?0.01), whereas in males, the caudate volumes were correlated with fluid figural intelligence (r?=?0.507, p?=?0.01). Numeric intelligence was correlated with right-lateralised caudate nucleus volumes for both females and males, but only for crystallised intelligence (r?=?0.306, p?=?0.04 and r?=?0.459, p?=?0.04, respectively). The associations were not mediated by prefrontal cortical subfield volumes when controlling with partial correlation analyses. Conclusions/Significance The findings of our exploratory analysis indicate that figural and numeric intelligence aspects, but not verbal aspects, are strongly associated with basal ganglia volumes. Unlike numeric intelligence, the type of figural intelligence appears to be related to distinct basal ganglia nuclei in a sex-specific manner. Subcortical brain structures thus may contribute substantially to cognitive performance.

Rhein, Cosima; Muhle, Christiane; Richter-Schmidinger, Tanja; Alexopoulos, Panagiotis; Doerfler, Arnd; Kornhuber, Johannes



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)



Full Color Holographic Endoscopy  

NASA Astrophysics Data System (ADS)

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

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



Correlated Volume-Energy Fluctuations of Phospholipid Membranes: A Simulation Study  

PubMed Central

This paper reports all-atom computer simulations of five phospholipid membranes (DMPC, DPPC, DMPG, DMPS, and DMPSH) with focus on the thermal equilibrium fluctuations of volume, energy, area, thickness, and chain order. At constant temperature and pressure, volume and energy exhibit strong correlations of their slow fluctuations (defined by averaging over 0.5 ns). These quantities, on the other hand, do not correlate significantly with area, thickness, or chain order. The correlations are mainly reported for the fluid phase, but we also give some results for the ordered (gel) phase of two membranes, showing a similar picture. The cause of the observed strong correlations is identified by splitting volume and energy into contributions from tails, heads, and water, and showing that the slow volume?energy fluctuations derive from van der Waals interactions of the tail region; they are thus analogous to the similar strong correlations recently observed in computer simulations of the Lennard-Jones and other simple van der Waals type liquids (U. R. Pedersen et al., Phys. Rev. Lett.2008, 100, 015701). The strong correlations reported here confirm one crucial assumption of a recent theory for nerve signal propagation proposed by Heimburg and Jackson (T. Heimburg and A. D. Jackson, Proc. Natl. Acad. Sci.2005, 102, 9790?9795).



Correlated volume-energy fluctuations of phospholipid membranes: a simulation study.  


This paper reports all-atom computer simulations of five phospholipid membranes (DMPC, DPPC, DMPG, DMPS, and DMPSH) with focus on the thermal equilibrium fluctuations of volume, energy, area, thickness, and chain order. At constant temperature and pressure, volume and energy exhibit strong correlations of their slow fluctuations (defined by averaging over 0.5 ns). These quantities, on the other hand, do not correlate significantly with area, thickness, or chain order. The correlations are mainly reported for the fluid phase, but we also give some results for the ordered (gel) phase of two membranes, showing a similar picture. The cause of the observed strong correlations is identified by splitting volume and energy into contributions from tails, heads, and water, and showing that the slow volume-energy fluctuations derive from van der Waals interactions of the tail region; they are thus analogous to the similar strong correlations recently observed in computer simulations of the Lennard-Jones and other simple van der Waals type liquids (U. R. Pedersen et al., Phys. Rev. Lett. 2008, 100, 015701). The strong correlations reported here confirm one crucial assumption of a recent theory for nerve signal propagation proposed by Heimburg and Jackson (T. Heimburg and A. D. Jackson, Proc. Natl. Acad. Sci. 2005, 102, 9790-9795). PMID:20095587

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



Holographic string encoding.  


In this article, we apply a special case of holographic representations to letter position coding. We translate different well-known schemes into this format, which uses distributed representations and supports constituent structure. We show that in addition to these brain-like characteristics, performances on a standard benchmark of behavioral effects are improved in the holographic format relative to the standard localist one. This notably occurs because of emerging properties in holographic codes, like transposition and edge effects, for which we give formal demonstrations. Finally, we outline the limits of the approach as well as its possible future extensions. PMID:21428993

Hannagan, Thomas; Dupoux, Emmanuel; Christophe, Anne



Holographically corrected telescopes  

NASA Astrophysics Data System (ADS)

Holographic correction of low-quality telescopes is an inexpensive method of obtaining large aperture devices suitable for lidar, imaging, and directed energy weaponry. We present an analysis of two different methods for producing diffraction-limited telescopes from the holographic correction of spherical mirrors. These evaluations are essential for choosing the optimal design for a given telescope application. Included in our discussion are the results from preliminary experiments into the various designs. The aim of the project is construct the first ever holographically corrected astronomical telescope for both ground and space-based operations.

Andersen, Geoff; Knize, Randall J.



Hippocampal volume reduction correlates with apathy in traumatic brain injury, but not schizophrenia.  


Apathy commonly accompanies both traumatic brain injury (TBI) and deficit syndrome schizophrenia (DSZ), despite unclear neurological bases. The authors examined differences in cortical thickness and subcortical/cerebellar regional volumes between adult TBI survivors, patients with DSZ, and healthy-control subjects by use of 3-D magnetic resonance imaging (MRI), and correlated imaging findings with clinical ratings of apathy and selected cognitive test scores. Imaging findings revealed specific areas of volume reduction in TBI survivors and areas of cortical thinning among patients with DSZ. The severity of apathy symptoms was similar across patient groups; however, severity of apathy was only correlated with imaging findings in TBI survivors. PMID:24247856

Takayanagi, Yoichiro; Gerner, Gwendoly; Takayanagi, Mizuho; Rao, Vani; Vannorsdall, Tracy D; Sawa, Akira; Schretlen, David J; Cascella, Nicola G



Correlation of gross tumor volume excursion with potential benefits of respiratory gating  

SciTech Connect

Purpose: To test the hypothesis that the magnitude of thoracic tumor motion can be used to determine the desirability of respiratory gating. Methods and materials: Twenty patients to be treated for lung tumors had computed tomography image data sets acquired under assisted breath hold at normal inspiration (100% tidal volume), at full expiration (0% tidal volume), and under free breathing. A radiation oncologist outlined gross tumor volumes (GTVs) on the breath-hold computed tomographic images. These data sets were registered to the free-breathing image data set. Two sets of treatment plans were generated: one based on an internal target volume explicitly formed from assessment of the excursion of the clinical target volume (CTV) through the respiratory cycle, representing an ungated treatment, and the other based on the 0% tidal volume CTV, representing a gated treatment with little margin for residual motion. Dose-volume statistics were correlated to the magnitude of the motion of the center of the GTV during respiration. Results: Patients whose GTVs were >100 cm{sup 3} showed little decrease in lung dose under gating. The other patients showed a correlation between the excursion of the center of the GTV and a reduction in potential lung toxicity. As residual motion increased, the benefits of respiratory gating increased. Conclusion: Gating seems to be advantageous for patients whose GTVs are <100 cm{sup 3} and for whom the center of the GTV exhibits significant motion, provided residual motion under gating is kept small.

Starkschall, George [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)]. E-mail:; Forster, Kenneth M. [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Kitamura, Kei [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Department of Radiology, Hokkaido University, Graduate School of Medicine, Sapporo (Japan); Cardenas, Alex [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Tucker, Susan L. [Department of Biomathematics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Stevens, Craig W. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)



Holographic Stereogram Conversion Process.  

National Technical Information Service (NTIS)

Practical methods are described for making holographic stereograms from aerialphoto transparencies. The stereograms are viewed in white light without spectacles. They use holography to selectively convey left and right stereoscopic viewpoints to respectiv...

J. T. McCrickerd



Holographic Chaplygin gas model  

Microsoft Academic Search

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

M. R. Setare



Holographic Phase Correction.  

National Technical Information Service (NTIS)

The technique of holographic phase correction is described. This scheme offers advantages over more traditional methods, and is applicable to a wide range of problems. The merits and limitations of the technique are investigated by a detailed theoretical ...

C. W. Slinger



Holographic Random Access Memories.  

National Technical Information Service (NTIS)

This program, originally proposed in early 1991 and eventually funded in late 1992, represented a pioneering effort to demonstrate, using only commercially available components and proven technologies, the technical feasibility of 3-D holographic memories...

S. Raffensperger



A Holographic Road Show.  

ERIC Educational Resources Information Center

Describes the viewing sessions and the holograms of a holographic road show. The traveling exhibits, believed to stimulate interest in physics, include a wide variety of holograms and demonstrate several physical principles. (GA)

Kirkpatrick, Larry D.; Rugheimer, Mac



Holographic Optical Coherence Imaging  

Microsoft Academic Search

Holographic optical coherence imaging (OCI) is a wide-field depth-gated direct imaging approach that acquires en face images from a fixed depth inside scattering media without the need for computed reconstruction [1]. A holographic real-time\\u000a film (most commonly a photorefractive quantum well structure [2]) provides the coherent demodulation that extracts information-bearing\\u000a light from the multiply-scattered statistically incoherent background. The photorefractive effect

D. D. Nolte; K. Jeong; P. M. W. French; J. Turek


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.




Holographic entanglement entropy in nonlocal theories  

NASA Astrophysics Data System (ADS)

We compute holographic entanglement entropy in two strongly coupled non-local field theories: the dipole and the noncommutative deformations of SYM theory. We find that entanglement entropy in the dipole theory follows a volume law for regions smaller than the length scale of nonlocality and has a smooth cross-over to an area law for larger regions. In contrast, in the noncommutative theory the entanglement entropy follows a volume law for up to a critical length scale at which a phase transition to an area law occurs. The critical length scale increases as the UV cutoff is raised, which is indicative of UV/IR mixing and implies that entanglement entropy in the noncommutative theory follows a volume law for arbitrary large regions when the size of the region is fixed as the UV cutoff is removed to infinity. Comparison of behaviour between these two theories allows us to explain the origin of the volume law. Since our holographic duals are not asymptotically AdS, minimal area surfaces used to compute holographic entanglement entropy have novel behaviours near the boundary of the dual spacetime. We discuss implications of our results on the scrambling (thermalization) behaviour of these nonlocal field theories.

Karczmarek, Joanna L.; Rabideau, Charles



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



Contraction of neuronal branching volume: an anatomic correlate of Pavlovian conditioning.  

PubMed Central

Associative memory of the mollusc Hermissenda crassicornis, previously correlated with changes of specific K+ currents, protein phosphorylation, and increased synthesis of mRNA and specific proteins, is here shown to be accompanied by macroscopic alteration in the structure of a single identified neuron, the medial type B photoreceptor cell. Four to five days after training, terminal arborizations of B cells iontophoretically injected with Ni2+ ions and then treated with rubeanic acid were measured with charge-coupled device (CCD)-digitized pseudocolor images of optical sections under "blind" conditions. Boundary volumes enclosing medial-type B-cell arborizations from classically conditioned animals were unequivocally reduced compared with volumes for naive animals or those trained with unpaired stimuli. Branch volume magnitude was correlated with input resistance of the medial type B-cell soma. Such associative learning-induced structural changes may share function with "synapse elimination" described in developmental contexts. Images

Alkon, D L; Ikeno, H; Dworkin, J; McPhie, D L; Olds, J L; Lederhendler, I; Matzel, L; Schreurs, B G; Kuzirian, A; Collin, C



Holographic Enhanced Remote Sensing System.  

National Technical Information Service (NTIS)

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 thermo...

H. P. Iavecchia E. S. Gaynor L. Huff W. T. Rhodes E. H. Rothenheber



Effects of excluded volume and correlated molecular orientations on Förster resonance energy transfer in liquid water.  


Förster theory for the survival probability of excited chromophores is generalized to include the effects of excluded volume and orientation correlation in the molecular distribution. An analytical expression for survival probability was derived and written in terms of a few simple elementary functions. Because of the excluded volume, the survival probability exhibits exponential decay at early times and stretched exponential decay at later times. Experimental schemes to determine the size of the molecular excluded volume are suggested. With the present generalization of theory, we analyzed vibrational resonance energy transfer kinetics in neat water. Excluded volume effects prove to be important and slow down the kinetics at early times. The majority of intermolecular resonance energy transfer was found to occur with exponential kinetics, as opposed to the stretched exponential behavior predicted by Förster theory. Quantum yields of intra-molecular vibrational relaxation, intra-, and intermolecular energy transfer were calculated to be 0.413, 0.167, and 0.420, respectively. PMID:24735306

Yang, Mino



Correlation and Estimation of Vapor-Liquid Critical Properties. Part 2: Critical Pressures and Critical Volumes of Organic Compounds.  

National Technical Information Service (NTIS)

A method of correlating critical temperatures was established. The method is extended to critical pressures and critical volumes, utilizing for these properties the methods of correlation proposed by Lydersen. Numerous determinations of critical propertie...

D. Ambrose



Phenanthrenequinone-doped copolymers for holographic data storage  

NASA Astrophysics Data System (ADS)

Two new types of phenanthrenequinone-doped poly(methyl-methacrylate) (PQ/PMMA) are proposed and fabricated for volume holographic recording. In these materials, the matrix of PQ/PMMA is replaced by the copolymers, which are composed of either poly(trimethylolpropane triacrylate-co-methyl methacrylate) or poly(2-phenoxyethyl acrylate-co-methyl methacrylate), respectively. With the chemical analyses of the response of these materials with respect to light exposure, the physical mechanism of the holographic recording in those copolymer samples is investigated. In addition, the holographic characteristics, including the dynamic range and sensitivity, have been measured. The experimental results demonstrate that the modification of the monomer components can enhance holographic characteristics of PQ/PMMA.

Lin, Shiuan Huei; Chen, Po-Lin; Lin, June-Hwa



Holographic dark energy and late cosmic acceleration  

NASA Astrophysics Data System (ADS)

It has been persuasively argued that the number of effective degrees of freedom of a macroscopic system is proportional to its area rather than to its volume. This entails interesting consequences for cosmology. Here we present a model based on this 'holographic principle' that accounts for the present stage of accelerated expansion of the Universe and significantly alleviates the coincidence problem also for non-spatially flat cosmologies. Likewise, we comment on a recently proposed late transition to a fresh decelerated phase.

Pavón, Diego



Visual Perception and Holographic Displays  

NASA Astrophysics Data System (ADS)

Holographic displays have the potential to reproduce the natural parallax and focusing affordances of real scenes. Although holographic displays are still far from maturity, no other display technologies have the potential to reproduce these affordances as accurately. This paper reviews visual human-factors considerations for current and future holographic displays.

Barabas, James; Bove, V. Michael, Jr.



Holographic filter stabilized laser for use as an optical frequency reference for HDWDM systems  

Microsoft Academic Search

The relative optical frequency stability of a narrow bandwidth volume optical holographic filter stabilized laser in comparision with a optical reference unit at 1547.825nm was examined. The two optical signals were heterodyned to measure the frequency stability of the holographic filter stabilized laser,

U. H. P. Fischer; N. Karlovac



Novel Speckle Angular-Shift Multiplexing for High-Density Holographic Storage.  

National Technical Information Service (NTIS)

The volume holographic optical data storage has been an important and exciting area of research. Recently the more interested study for a high-density holographic memory is focused on the speckle wave used as the coded reference wave in various multiplexi...

G. Jin M. Wu P. Zhang Q. He Y. Ya



Correlation between T-Wave Alternans and Cardiac Volume Status via Intrathoracic Impedance Measurements  

PubMed Central

Introduction. The presence of T-wave alternans (TWA) has been shown to correlate with a higher risk for sudden cardiac death. The mechanism of TWA may be related to abnormalities in intracellular calcium handling, which is a mechanism in heart failure and associated arrhythmias as well. However, an association between TWA and cardiac volume status has not been demonstrated. Methods Used. We report the case of a 54-year-old man with a dilated cardiomyopathy who had a biventricular defibrillator system implanted with intrathoracic impedance measurement capability. We performed baseline TWA testing, which was normal and was associated with normal clinical status and normal intrathoracic impedance. We followed intrathoracic impedance measurements, and when the measurement suggested volume overload eight months later, we repeated the TWA test. TWA was grossly positive, and volume overload was corroborated with clinical heart failure. The patient was diuresed, and when clinical status and intrathoracic impedance returned to normal a month later, we repeated TWA, which was again negative. Conclusion. This case demonstrates a correlation between cardiac volume status, as measured by intrathoracic impedance measurements, and TWA status. This data suggests that conditions of volume overload such as heart failure could be causally related to increased TWA, perhaps by the common mechanism of altered intracellular calcium handling.

Dizon, Jose'; Hickey, Kathleen; Garan, Hasan



DIAGNOdent measurements and correlation with the depth and volume of minimally invasive cavity preparations.  


In this clinical study, DIAGNOdent (KaVo) was used to assess previously diagnosed carious lesions in the pits and fissures of first and second molars. The measurements from this device were correlated with the depth and volume of the cavity preparations that resulted from minimal intervention to remove occlusal carious lesions. Twenty-five patients, 18 years of age and older, who were previously scheduled for an occlusal restoration due to caries, were recruited and enrolled in this clinical study. These patients had 48 qualifying teeth without previous restorations, sealants or other carious lesions. The occlusal surface of each study tooth was cleaned utilizing ProphyFlex2 (KaVo). Two dentists separately traced the pit and fissure system of each tooth using DIAGNOdent for two 15-second periods each. The peak reading of each of the four measurements was recorded. An impression of the occlusal surface of each tooth was recorded with a polyvinyl siloxane bite registration material. The carious lesions were removed with an air abrasion unit employing a 0.015-inch nozzle opening utilizing minimal operative intervention. A low viscosity polyvinyl siloxane was used to take an impression of the cavity preparation impression, using the bite registration impression to form the occlusal surface of the preparation impression. The preparation impression volume was calculated from its weight, using the known density of the impression material. The greatest depth of the preparation was measured. The Pearson correlation coefficient was used to investigate any relationship between depth or volume of the preparation impression and the DIAGNOdent measurements. The correlation for preparation volume and maximum DIAGNOdent measurement was 0.191 (p = 0.189). Other logical subsets of cases also did not result in any statistically significant correlations between the DIAGNOdent readings and the depth or volume of the final cavity preparations. PMID:16802636

Hamilton, James C; Gregory, William A; Valentine, John B



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



Early Cell Death Detection with Digital Holographic Microscopy  

PubMed Central

Background Digital holography provides a non-invasive measurement of the quantitative phase shifts induced by cells in culture, which can be related to cell volume changes. It has been shown previously that regulation of cell volume, in particular as it relates to ionic homeostasis, is crucially involved in the activation/inactivation of the cell death processes. We thus present here an application of digital holographic microscopy (DHM) dedicated to early and label-free detection of cell death. Methods and Findings We provide quantitative measurements of phase signal obtained on mouse cortical neurons, and caused by early neuronal cell volume regulation triggered by excitotoxic concentrations of L-glutamate. We show that the efficiency of this early regulation of cell volume detected by DHM, is correlated with the occurrence of subsequent neuronal death assessed with the widely accepted trypan blue method for detection of cell viability. Conclusions The determination of the phase signal by DHM provides a simple and rapid optical method for the early detection of cell death.

Pavillon, Nicolas; Kuhn, Jonas; Moratal, Corinne; Jourdain, Pascal; Depeursinge, Christian



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



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



Self-correlation fiber specklegram sensor using volume characteristics of speckle patterns  

NASA Astrophysics Data System (ADS)

Tuning of the dynamic range of a micro-displacement fiber specklegram sensor based on two-wave mixing on a photorefractive material Bi12SiO20 (BSO) and self-correlation operations of speckle patterns is experimentally demonstrated. The high modal interference present in a standard plastic optical fiber (POF) allows generating a Gaussian pattern of subjective speckle, which is recorded in the volume crystal. The volume characteristics of the fiber speckle are changed using a pupil aperture adjacent to the imaging lens of the speckle. A notorious effect of the three dimensional structure of the speckle on the dynamic range of the metrological system is observed, such that, the performance of the sensor can be improved by a simple mechanical action on the pupil aperture. The behavior of the self-correlation loss of the sensor can be adequately described by a squared normalized Bessel function.

Gómez, Jorge A.; Salazar, Ángel



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)



Holographic bosonic technicolor  

SciTech Connect

We consider a technicolor model in which the expectation value of an additional, possibly composite, scalar field is responsible for the generation of fermion masses. We define the dynamics of the strongly coupled sector by constructing its holographic dual. Using the AdS/CFT correspondence, we study the S parameter and the phenomenology of the light technihadrons. We find that the S parameter is small over a significant region of the model's parameter space. The particle spectrum is distinctive and includes a nonstandard Higgs boson as well as heavier hadronic resonances. Technihadron masses and decay rates are calculated holographically, as a function of the model's parameters.

Carone, Christopher D.; Erlich, Joshua; Tan, Jong Anly [Particle Theory Group, Department of Physics, College of William and Mary, Williamsburg, Virginia 23187-8795 (United States)



Computer generated holographic microtags  


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)



What is Holographic Storage?  

NSDL National Science Digital Library

InPhase Technologies, a company based outside of Denver, Colorado, recently unveiled the product of several years' research. Its "holographic data storage media" is shown to be capable of much greater storage capacity than DVDs, and is scheduled for a limited commercial release in 2003. This page on the InPhase Web site explains some of the underlying concepts involved in holographic storage. There are two main sections: one is a brief overview of the technology's features and benefits, while the other is a more thorough description of the process of reading and recording data. A video demonstrating the technology is planned to appear on the site.


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

PubMed Central

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

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



Holographic non-Fermi-liquid fixed points.  


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



Tomographic holographic interferometry for unsteady compressible flows  

NASA Astrophysics Data System (ADS)

The study of an underexpanded compressible jet using pulsed, phase- shifted interferometry in conjunction with a 9 beam tomographic illumination system is described. A plane wave holographic interferometer using a pulsed ruby laser has been adapted to provide multiple illumination directions of a volume that is approximately 4 centimeters on a side. This set-up is being used to study the transient behavior of compressible jets and may be operated using double-exposure holographic interferometry to study the instantaneous behavior of the flow; alternatively, the system may be operated in a double-pulse mode to study the fluctuations in the flow. The tomographic reconstructions are made using a Fourier-Bassel expansion. To illustrate the performance of the system, an underexpanded nozzle flow producing a series of compression-rarefaction 'diamonds' was studied. The images show sharp reconstructions of the compression-rarefaction diamond pattern as well as some interesting secondary flow structures.

Timmerman, Brenda H.; Watt, David W.



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)



Holographic telescope arrays  

Microsoft Academic Search

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

Adolf W. Lohmann; Frank Sauer



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



Holographic quarterwave plates.  


Quarterwave plates can be made as holographic gratings in positive photoresist. We studied the effect of the grating period and relief depth on the phase retardation and on the rotation of the polarization of the transmitted light. Experiments were performed with gratings of different periods, which also exhibit an antireflection property. PMID:20567411

Cescato, L H; Gluch, E; Streibl, N



Holographic Random Access Memory.  

National Technical Information Service (NTIS)

We designed and demonstrated a fully working, large-scale random-access holographic memory. The recording medium is a Fe-doped LiNb03 photorefractive crystal. The storage capacity of the memory is limited by the dynamic range and geometric limitation. The...

D. Psaltis



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)



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



Left atrial volume index in healthy subjects: clinical and echocardiographic correlates.  


Left atrial (LA) size is related to cardiovascular morbidity and mortality. The relative role of multiple determinants of LA morphology in healthy subjects remains incompletely defined. The aim of this study is to define normal ranges for LA diameters and volume index (LAVi), and to investigate clinical and echocardiographic correlates. A total of 1480 healthy individuals (mean age 36.1 ± 15.5 years, range 20-80; 61% males) underwent a comprehensive transthoracic echocardiography exam including assessment of LAVi calculated using the biplane area-length method at the apical four-chamber and two-chamber views at ventricular end systole (maximum LA size) and indexed for body surface area (BSA). Mean LAVi in the overall population was 29.5 ± 10.8 mL/m(2) (range: 26.1-41.8 mL/m(2) ). Distinct higher values were found in subjects ?50 years as compared with those <50 years of age (33.4 ± 12.5 vs. 29.1 ± 13.5; P < 0.001). On univariate analysis, LA volume was significantly associated with age (r = 0.48, P < 0.0001), male gender (r = 0.28, P < 0.05), BSA (r = 0.51, P < 0.0001), mitral E/E' (r = 0.47, P < 0.0001), LV end-diastolic volume (r = 0.52, P < 0.0001), and LV mass index (r = 0.31, P < 0.05). Multivariable analysis identified age, BSA, LV end-diastolic volume, and mitral E/E' ratio as the only independent determinants of LA volume (model R(2) = 0.54, P < 0.0001). Gender was an independent predictor of most absolute LA volume, but following normalization to BSA, some associations became nonsignificant. In healthy individuals LAVi vary significantly by age, BSA, diastolic function, and LV dimensions, with lesser effects of gender. PMID:23594028

D'Andrea, Antonello; Riegler, Lucia; Rucco, Maria Antonietta; Cocchia, Rosangela; Scarafile, Raffaella; Salerno, Gemma; Martone, Francesca; Vriz, Olga; Caso, Pio; Calabrò, Raffaele; Bossone, Eduardo; Russo, Maria Giovanna



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.



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


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



Intracranial pressure pulse waveform correlates with aqueductal cerebrospinal fluid stroke volume  

PubMed Central

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

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



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


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



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

NASA Astrophysics Data System (ADS)

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.

Guo, Ning; Zhao, Jidong



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



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.

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



Demonstration of an All-Optical Associative Holographic Memory.  

National Technical Information Service (NTIS)

A new type of associative holographic memory is described with some related results. The memory can retrieve overlapping images which are stored in a volume hologram. The storage and retrieval of more than one image is demonstrated for the first time. The...

A. Yariv S. Kwong K. Kyuma



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.



Holographic laser imaging systems  

NASA Astrophysics Data System (ADS)

Holographix, Inc. has developed a family of holographic laser scanning systems for printing applications. These systems have been designed to significantly reduce production costs without compromising print quality. Holographix has been awarded several patents on its designs and licenses its technology to OEMs. The optical designs for these systems, developed with Optical Research Associates (ORAR), range from `low-end' laser scanners for 300 dpi and 600 dpi desktop printers to prepress scanners with 1200 dpi and greater resolution. The designs are well corrected for linearity and line bow. Unique features of these designs are telecentricity at the focal plane and the achromatic correction for both cross-scan and in-scan errors due to wavelength variations. The achromatization capability allows the use of laser diode sources for a major cost savings and telecentricity improves in-use performance. This paper briefly describes the concept of holographic laser scanning and key features of the optical designs.

Sagan, Stephen F.; Rowe, David M.



Holographic charge density waves  

NASA Astrophysics Data System (ADS)

We discuss a gravity dual of a charge density wave consisting of a U(1) gauge field and two scalar fields in the background of a Schwarzschild-AdS 4 black hole together with an antisymmetric field (probe limit). Interactions drive the system to a phase transition below a critical temperature. We numerically compute the ground states characterized by modulated solutions for the gauge potential corresponding to a dynamically generated unidirectional charge density wave in the conformal field theory. Signatures of the holographic density waves are retrieved by studying the dynamical response to an external electric field. We find that this novel holographic state shares many common features with the standard condensed matter version of charge density wave systems.

Aperis, Alexandros; Kotetes, Panagiotis; Papantonopoulos, Eleftherios; Siopsis, George; Skamagoulis, Petros; Varelogiannis, Georgios



Holographic laser protection device  

SciTech Connect

A holographic reflector is described for reflecting laser radiation at a predetermined wavelength which is incident over a predetermined angular range, the reflector comprising: holograms conterminously and adjacently disposed on at least one substrate, each of the holograms having holographic fringes with predetermined spacing which make a predetermined angle with respect to the normal to the surface of the substrate. Each of the holograms has fringe spacings which are different from the fringe spacing of a hologram adapted to optimally reflect the predetermined wavelength. Each hologram has fringe spacings and predetermined angles which are adapted to reflect the predetermined wavelength over separate angular ranges which are different from an angular range associated with a hologram adapted to optimally reflect the predetermined wavelength. The fringe spacings and predetermined angles are such that each of the holograms reflects the predetermined wavelength within the predetermined angular ranges which together comprise the predetermined angular range.

Moss, G.E.; Chern, M.J.; Dobbs, T.L.



Holographic Plossl Retroreflectors  

NASA Technical Reports Server (NTRS)

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

Waluschka, Eugene



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



Holographic Chaplygin DGP cosmologies  

Microsoft Academic Search

In the present paper, we present an extra dimensions inspired model that is\\u000abuilt on the DGP brane-world scenario, then we take the dark energy component\\u000aon the brane to be a Chaplygin gas. After that we consider a holographic model\\u000aof Chaplygin gas in the framework of DGP cosmology. We show that the\\u000aholographic Chaplygin gas can mimic a




Holographic bosonic technicolor  

Microsoft Academic Search

We consider a technicolor model in which the expectation value of an\\u000aadditional, possibly composite, scalar field is responsible for the generation\\u000aof fermion masses. We define the dynamics of the strongly coupled sector by\\u000aconstructing its holographic dual. Using the AdS\\/CFT correspondence, we study\\u000athe S parameter and the phenomenology of the light technihadrons. We find that\\u000athe S

Christopher D. Carone; Joshua Erlich; Jong Anly Tan



Recording Interferograms Holographically  

NASA Technical Reports Server (NTRS)

Images of experiments stored for later analysis Classical interferometer modified for holography by removing entrance semireflecting mirror and inserting holographic recording in one of legs. Collimated laser beam projected through hologram and directed to remaining semitransparent mirror. Combines with reference beam from same laser to form virtual image of original experiment. Developed for experiments on crystal growth during space flights. Images recorded rapidly under constraints of experiments and later examined on ground.

Comeens, E. R.; Kurtz, R. L.



Baryons in holographic QCD  

SciTech Connect

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

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



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.



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)



Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE)  

NASA Technical Reports Server (NTRS)

Scanning holographic lidar receivers are currently in use in two operational lidar systems, PHASERS (Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing) and now HARLIE (Holographic Airborne Rotating Lidar Instrument Experiment). These systems are based on volume phase holograms made in dichromated gelatin (DCG) sandwiched between 2 layers of high quality float glass. They have demonstrated the practical application of this technology to compact scanning lidar systems at 532 and 1064 nm wavelengths, the ability to withstand moderately high laser power and energy loading, sufficient optical quality for most direct detection systems, overall efficiencies rivaling conventional receivers, and the stability to last several years under typical lidar system environments. Their size and weight are approximately half of similar performing scanning systems using reflective optics. The cost of holographic systems will eventually be lower than the reflective optical systems depending on their degree of commercialization. There are a number of applications that require or can greatly benefit from a scanning capability. Several of these are airborne systems, which either use focal plane scanning, as in the Laser Vegetation Imaging System or use primary aperture scanning, as in the Airborne Oceanographic Lidar or the Large Aperture Scanning Airborne Lidar. The latter class requires a large clear aperture opening or window in the aircraft. This type of system can greatly benefit from the use of scanning transmission holograms of the HARLIE type because the clear aperture required is only about 25% larger than the collecting aperture as opposed to 200-300% larger for scan angles of 45 degrees off nadir.

Schwemmer, Geary K.



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



Focal volume optics and experimental artifacts in confocal fluorescence correlation spectroscopy.  

PubMed Central

Fluorescence correlation spectroscopy (FCS) can provide a wealth of information about biological and chemical systems on a broad range of time scales (<1 micros to >1 s). Numerical modeling of the FCS observation volume combined with measurements has revealed, however, that the standard assumption of a three-dimensional Gaussian FCS observation volume is not a valid approximation under many common measurement conditions. As a result, the FCS autocorrelation will contain significant, systematic artifacts that are most severe with confocal optics when using a large detector aperture and aperture-limited illumination. These optical artifacts manifest themselves in the fluorescence correlation as an apparent additional exponential component or diffusing species with significant (>30%) amplitude that can imply extraneous kinetics, shift the measured diffusion time by as much as approximately 80%, and cause the axial ratio to diverge. Artifacts can be minimized or virtually eliminated by using a small confocal detector aperture, underfilled objective back-aperture, or two-photon excitation. However, using a detector aperture that is smaller or larger than the optimal value (approximately 4.5 optical units) greatly reduces both the count rate per molecule and the signal-to-noise ratio. Thus, there is a tradeoff between optimizing signal-to-noise and reducing experimental artifacts in one-photon FCS.

Hess, Samuel T; Webb, Watt W



Bacterial spore heat resistance correlated with water content, wet density, and protoplast/sporoplast volume ratio.  

PubMed Central

Five types of dormant Bacillus spores, between and within species, were selected representing a 600-fold range in moist-heat resistance determined as a D100 value. The wet and dry density and the solids and water content of the entire spore and isolated integument of each type were determined directly from gram masses of material, with correction for interstitial water. The ratio between the volume occupied by the protoplast (the structures bounded by the inner pericytoplasm membrane) and the volume occupied by the sporoplast (the structures bounded by the outer pericortex membrane) was calculated from measurements made on electron micrographs of medially thin-sectioned spores. Among the various spore types, an exponential increase in the heat resistance correlated directly with the wet density and inversely with the water content and with the protoplast/sporoplast volume ratio. Altogether with results supported a hypothesis that the extent of heat resistance is based in whole or in part on the extent of dehydration and diminution of the protoplast in the dormant spore, without implications about physiological mechanisms for attaining this state. Images

Beaman, T C; Greenamyre, J T; Corner, T R; Pankratz, H S; Gerhardt, P



Large-scale DCG transmission holographic gratings for astronomy  

NASA Astrophysics Data System (ADS)

The recent interest of the astronomer community for volume phase holographic gratings is directly related to the enhancement of spectrograph throughput since this kind of grating can rise higher diffraction efficiency. Indeed, dichromated gelatine technology has demonstrated capability for 70-90% efficiency. From the heritage of several diffractive and holographic projects and applications, the Centre Spatial de Liege has recently decided to invest in the large-scale DCG grating technology. This paper will present the new facility which is now fully operational, its capability and first results obtained.

Blanche, Pierre-Alexandre; Habraken, Serge L.; Lemaire, Philippe C.; Jamar, Claude A. J.



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.



Method and apparatus for holographic wavefront diagnostics  


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.



Method and apparatus for holographic wavefront diagnostics  


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)



Friedmann Propulsion in an Flat Holographic Universe  

Microsoft Academic Search

Because of inversion symmetries in holographic systems, the spatial compression of lower-dimensional holographic memory leads to an expansion of the holographic image and vice versa (scaling duality), where the geometric mean between the small quantum memory and cosmic image scale defines the inversion scale, the unit scale to normalize the global holographic currents of momentum exchange. Assigning to the cosmic

Bernd Binder



Optical fiber holographic speckle interferometry  

Microsoft Academic Search

Pulsed laser is transmitted by optical fibers, the polarity is changed into random distribution and the coherence is decreased somewhat. But when used in holographic interferometry, optical fibers have substantial advantages, having no influence on formation and clarity of coherent fringes. Two kinds of optical fiber speckle holographic interferometry systems are often used. The first kind employs an optical bundle

Guozhi Wang



Holographic representation of local bulk operators  

SciTech Connect

The Lorentzian anti-de Sitter/conformal field theory correspondence implies a map between local operators in supergravity and nonlocal operators in the CFT. By explicit computation we construct CFT operators which are dual to local bulk fields in the semiclassical limit. The computation is done for general dimension in global, Poincare and Rindler coordinates. We find that the CFT operators can be taken to have compact support in a region of the complexified boundary whose size is set by the bulk radial position. We show that at finite N the number of independent commuting operators localized within a bulk volume saturates the holographic bound.

Hamilton, Alex; Kabat, Daniel [Department of Physics Columbia University, New York, New York 10027 (United States); Lifschytz, Gilad [Department of Mathematics and Physics and CCMSC University of Haifa at Oranim, Tivon 36006 (Israel); Lowe, David A. [Department of Physics Brown University, Providence, Rhode Island 02912 (United States)



Projective properties of holographic speckle screens  

NASA Astrophysics Data System (ADS)

This paper discusses axial holographic speckle screens for projecting images recorded in a volume photosensitive material based on dichromated gelatin. It is shown that, when speckle screens are recorded with radiation in the sensitivity region of dichromated gelatin at a wavelength of 442?nm, it is possible to reconstruct images with radiation of another region of the spectrum, including with white light. The projective properties of the screens are investigated, and the effect of light concentration by means of the screen in the region of the visibility zone is demonstrated.

Ganzherli, N. M.; Denisyuk, Yu. N.; Maurer, I. A.; Chernykh, D. F.



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.



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.



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

SciTech Connect

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

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



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.



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


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



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

PubMed Central

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

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



Models of holographic superconductivity  

SciTech Connect

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

Aprile, Francesco [Institute of Cosmos Sciences and Estructura i Constituents de la Materia Facultat de Fisica, Universitat de Barcelona, Avenida Diagonal 647, 08028 Barcelona (Spain); Russo, Jorge G. [Institute of Cosmos Sciences and Estructura i Constituents de la Materia Facultat de Fisica, Universitat de Barcelona, Avenida Diagonal 647, 08028 Barcelona (Spain); Institucio Catalana de Recerca i Estudis Avancats (ICREA), Paseo Lluis Companys, 23, 08010 Barcelona (Spain)



Holographic superconductor with disorder  

NASA Astrophysics Data System (ADS)

We study the effects of disorder on a holographic superconductor by introducing a random chemical potential on the boundary. We consider various realizations of disorder and find that the critical temperature for superconductivity is enhanced. We also present evidence for a precise form of renormalization in this system. Namely, when the random chemical potential is characterized by a Fourier spectrum of the form k-2? we find that the spectra of the condensate and the charge density are again power laws, whose exponents are accurately and universally governed by linear functions of ?.

Areán, D.; Farahi, A.; Pando Zayas, L. A.; Landea, I. Salazar; Scardicchio, A.



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


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



Two-step phase-shifting fluorescence incoherent holographic microscopy.  


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



Experimental observation of one-dimensional quantum holographic imaging  

NASA Astrophysics Data System (ADS)

We report the experimental observation of quantum holographic imaging of one-dimensional object with entangled photon pairs, generated in a spontaneous parametric down-conversion process. The signal photons play both roles of ``object wave'' and ``reference wave'' in holography but are recorded by a point detector providing only encoding information, while the idler photons travel freely and are locally manipulated with spatial resolution. The holographic image is formed by the two-photon correlation measurement, although both the signal and idler beams are incoherent. Three types of quantum holography schemes are analyzed according to the detection regime of the signal photons.

Song, Xin-Bing; Xu, De-Qin; Wang, Hai-Bo; Xiong, Jun; Zhang, Xiangdong; Cao, De-Zhong; Wang, Kaige



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)



Holographic detection of photochemical holes  

NASA Astrophysics Data System (ADS)

The application of the holographic detection method to optical hole-burning spectroscopy is investigated. Crossed laser beams were used to induce spatially periodic changes in the spectral hole depth for chlorin (2,3-dihydroporhyrin) molecules embedded in a polyvinylbutyral (PVB) matrix at 4.2 K. It is shown that the holographic technique is a sensitive zero-background method for detecting weak signals associated with photochemical holes and is well suited to determine homogeneous linewidths. The results obtained demonstrate that the holographic technique represents an efficient tool for high-resolution studies in inhomogeneously broadened bands of complex organic molocules.

Renn, Alois; Meixner, Alfred J.; Wild, Urs P.; Burkhalter, Fritz A.



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)



Holographic portrait of Ronald Reagan  

NASA Astrophysics Data System (ADS)

The first holographic portrait of a President of the United States of America was recorded on 24 May 1991 in Santa Barbara, Calif. Ronald Reagan was the subject. The event was the first in a project that began some five years ago with the aim of producing an archive of Presidential pulsed holographic portraits. The authors discuss the inception and evolution of the project. They describe the unique interactions, communications, and scheduling as well as trials and triumphs involved in recording a holographic portrait of such a prominent public figure.

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



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)



Multifunctional photoreactive inorganic cages for three-dimensional holographic data storage.  


We demonstrate a holographic photopolymer based on multifunctional photoreactive inorganic cages, polyhedral oligomeric silsesquioxane (POSS). It is shown that a second photopolymerizable monomer, POSS, for the photopolymer, contributes to significantly enhance photosensitivity as well as refractive index modulation (Deltan). We also found that during the formation of holographic gratings, polymerization of POSS could effectively suppress volume shrinkage of photopolymer resin, owing to its filler-strengthening effect of inorganic cages accompanied with interpenetrating effect. PMID:19838237

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



Holographic interferometry with the compact arrowhead holographic setup.  


A symmetric off-axis holographic setup, shaped as an arrowhead, which requires neither a collimator nor a beam splitter, is presented. It is applied to measure small perpendicular-to-surface displacements and deformations and the magnetostriction of a body by holographic interferometry. It offers advantages such as implicit fulfilment of several hologram recording conditions, possible use of short coherence length light sources, low-cost, and significant immunity against mechanical perturbations. PMID:20479863

Ladera, Celso L



Correlation of transrectal and transabodominal ultrasound measurement of transition zone volume with post-operative enucleated adenoma volume in benign prostatic hypertrophy  

PubMed Central

Introduction Benign prostatic hyperplasia is a common disease of ageing men worldwide. Though transrectal ultrasonography (TRUS) is the standard in most parts of the world in evaluation of benign prostatic hyperplasia (BPH), it is rarely done in some less developed countries because of non availability of appropriate probes and or specialists. Transabdominal ultrasonography (TAUS) remains the mainstay in these areas. Some controversies still exist in literature about the accuracy of TAUS evaluation of prostatic volume in patients with BPH. This study aimed at comparing the transition zone volume estimation of the prostate on transrectal and transabdominal ultrasound with post-operative enucleated adenoma volume in Nigeria patients with BPH and to suggest better predictor of prostate volume in evaluation of BPH. Methods Forty-six (46) patients with lower urinary tract symptoms due to BPH attending the urologic clinic were evaluated ultrasonographically and eventually managed with open surgery (prostatectomy) after due counselling. The post operative samples were weighted using a sensitive top loading weighing balance and converted to volume. Since the specific gravity of the prostate is equivalent to that of water,the weight is the same as volume. Results Patients’ ages ranged between 59 and 90 years with a peak age incidence at seventh decade. Transition Zone (TZ) volume estimation on both transrectal and transabdominal ultrasound showed positive correlation with the post operative enucleated adenoma(r = 0.594, p < 0.001) but the transrectal method was more accurate. There was no significant relationship between the TZ volume and patients’ symptoms(r = 0.491, p = 0.007). Conclusion Both TRUS and TAUS are comparable at TZ volume estimation and therefore TAUS can be utilized in regions where intracavitary probes and or the expertise is/are not available.

Ajayi, Idowu; Aremu, Ademola; Olajide, Abimbola; Bello, Tope; Olajide, Folake; Adetiloye, Victor



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



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.



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

PubMed Central

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

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



Spectral beam combining with volume Bragg gratings: cross-talk analysis and optimization schemes  

Microsoft Academic Search

Volume Bragg gratings (VBGs) have been recognized as critical elements in various types of beam-combining applications, such as, design of super-parallel holographic optical correlators, coherent power beam-combiners and couplers, and spectral beam combiners (SBC) in which the output beams from several distinct laser sources are combined into a single-aperture beam. The obvious advantage of VBG stems from extremely narrow spectral

Armen Sevian; Oleksiy Andrusyak; Igor Ciapurin; George Venus; Leonid Glebov



Holographic framework for eternal inflation  

Microsoft Academic Search

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

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



Randomly addressable read\\/write\\/erase holographic memory system based on a dye-polymer recording medium  

Microsoft Academic Search

With a potential of up to 1012 bits\\/cm3, storage medium based on volume holographic memory can be the next generation of optical memory systems. However, any storage media for holographic memory must have large reflective index modulation, large available volume material while simultaneously preserving high response speed and low crosstalk. Photorefractive crystals, such as LiNbO3, SBN, and BaTiO3, are the

Shudong Wu; Jenkin C. Chen; Peter W. Low; Freddie S. Lin



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.

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



Photopolymerizable thiol-ene nanocomposite materials for holographic applications  

NASA Astrophysics Data System (ADS)

We describe an experimental investigation of the photopolymerization kinetics and volume holographic recording characteristics of silica nanoparticle-polymer nanocomposites using thiol-ene monomers capable of step-growth polymerization. We characterize the visible light curing kinetics of a thiol-ene monomer system consisting of secondary dithiol with high self-life stability and low odor and triene with rigid structure and high electron density by using real-time Fourier transform spectroscopy and photocalorimetry. In plane-wave volume holographic recording at a wavelength of 532 nm it is shown that while volume holograms recorded in the nanocomposites exhibit high transparency, their saturated refractive index modulation (?nsat) and material sensitivity (S) are as large as 1x10-2 and 1615 cm/J, respectively. The polymerization shrinkage is reduced as low as 0.4% as a result of the late gelation in conversion. These values meet the acceptable values for holographic data storage media (i.e., 5x10-3, 500 cm/J and 0.5% for ?nsat, S and shrinkage, respectively). The improved thermal stability of volume holograms recorded in the nanocomposites is also confirmed experimentally.

Tomita, Yasuo; Hata, Eiji; Yasui, Satoru; Mitsube, Ken



Losing forward momentum holographically  

NASA Astrophysics Data System (ADS)

We present a numerical scheme for solving Einstein’s Equations in the presence of a negative cosmological constant and an event horizon with planar topology. Our scheme allows for the introduction of a particular metric source at the conformal boundary. Such a spacetime has a dual holographic description in terms of a strongly interacting quantum field theory at nonzero temperature. By introducing a sinusoidal static metric source that breaks translation invariance, we study momentum relaxation in the field theory. In the long wavelength limit, our results are consistent with the fluid-gravity correspondence and relativistic hydrodynamics. In the small amplitude limit, our results are consistent with the memory function prediction for the momentum relaxation rate. Our numerical scheme allows us to study momentum relaxation outside these two limits as well.

Balasubramanian, Koushik; Herzog, Christopher P.



Holographic Recording Materials Development  

NASA Technical Reports Server (NTRS)

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

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



Striped holographic superconductor  

SciTech Connect

We study inhomogeneous solutions of a 3+1-dimensional Einstein-Maxwell-scalar theory. Our results provide a holographic model of superconductivity in the presence of a charge density wave sourced by a modulated chemical potential. We find that below a critical temperature T{sub c} superconducting stripes develop. We show that they are thermodynamically favored over the normal state by computing the grand canonical potential. We investigate the dependence of T{sub c} on the modulation's wave vector, which characterizes the inhomogeneity. We find that it is qualitatively similar to that expected for a weakly coupled Bardeen-Cooper-Schrieer theory, but we point out a quantitative difference. Finally, we use our solutions to compute the conductivity along the direction of the stripes.

Flauger, Raphael [Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Pajer, Enrico; Papanikolaou, Stefanos [Department of Physics, Cornell University, Ithaca, New York 14853 (United States)



Mach's holographic principle  

SciTech Connect

Mach's principle is the proposition that inertial frames are determined by matter. We put forth and implement a precise correspondence between matter and geometry that realizes Mach's principle. Einstein's equations are not modified and no selection principle is applied to their solutions; Mach's principle is realized wholly within Einstein's general theory of relativity. The key insight is the observation that, in addition to bulk matter, one can also add boundary matter. Given a space-time, and thus the inertial frames, we can read off both boundary and bulk stress tensors, thereby relating matter and geometry. We consider some global conditions that are necessary for the space-time to be reconstructible, in principle, from bulk and boundary matter. Our framework is similar to that of the black hole membrane paradigm and, in asymptotically anti-de Sitter space-times, is consistent with holographic duality.

Khoury, Justin [Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, Ontario, Canada N2L 2Y5 (Canada); Center for Particle Cosmology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Parikh, Maulik [Institute for Strings, Cosmology, and Astroparticle Physics, Columbia University, New York, New York 10027 (United States); Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Pune 411007 (India)



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



Holographic Vortex Coronagraph  

NASA Technical Reports Server (NTRS)

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

Palacios, David



Fast Holographic Wavefront Sensor  

NASA Astrophysics Data System (ADS)

There are several different types of wavefront sensors that can be used to measure the phase of an input beam. While they have widely varying modes of operation, they all require some computational overhead in order to deconstruct the phase from an optical measurement which greatly reduces the sensing speed. Furthermore, zonal detection methods, such as the Shack-Hartmann wavefront sensor (SHWFS) are not well suited to temporal changes in pupil obscuration such as can occur with scintillation. Here we present a modal detector that incorporates a multiplexed hologram to give a full description of wavefront error without the need for any calculations. The holographic wavefront sensor (HWFS) uses a hologram that is "pre-programmed" with all desired Zernike aberration components. An input beam of arbitrary phase will diffract into pairs of focused beams. Each pair represents a different aberration, and the amplitude is obtained by measuring the relative brightness of the pair of foci. This can be easily achieved by using conventional position sensing devices. In this manner, the amplitudes of each aberration components are directly sensed without the need for any calculations. As such, a complete characterization of the wavefront can be made at speeds of up to 100 kHz in a compact device and without the need for a computer or sophisticated electronics. In this talk we will detail the operation of the holographic wavefront sensor and present results of a prototype sensor as well as a modified design suitable for a closed-loop adaptive optics system. This new wavefront sensor will not only permit faster correction, but permit adaptive optics systems to work in extremely turbulent environments such as those encountered in fast-tracking systems and the Airborne Laser project.

Andersen, G.; Ghebremichael, F.; Gurley, K.


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.



An efficient and accurate 3D displacements tracking strategy for digital volume correlation  

NASA Astrophysics Data System (ADS)

Owing to its inherent computational complexity, practical implementation of digital volume correlation (DVC) for internal displacement and strain mapping faces important challenges in improving its computational efficiency. In this work, an efficient and accurate 3D displacement tracking strategy is proposed for fast DVC calculation. The efficiency advantage is achieved by using three improvements. First, to eliminate the need of updating Hessian matrix in each iteration, an efficient 3D inverse compositional Gauss–Newton (3D IC-GN) algorithm is introduced to replace existing forward additive algorithms for accurate sub-voxel displacement registration. Second, to ensure the 3D IC-GN algorithm that converges accurately and rapidly and avoid time-consuming integer-voxel displacement searching, a generalized reliability-guided displacement tracking strategy is designed to transfer accurate and complete initial guess of deformation for each calculation point from its computed neighbors. Third, to avoid the repeated computation of sub-voxel intensity interpolation coefficients, an interpolation coefficient lookup table is established for tricubic interpolation. The computational complexity of the proposed fast DVC and the existing typical DVC algorithms are first analyzed quantitatively according to necessary arithmetic operations. Then, numerical tests are performed to verify the performance of the fast DVC algorithm in terms of measurement accuracy and computational efficiency. The experimental results indicate that, compared with the existing DVC algorithm, the presented fast DVC algorithm produces similar precision and slightly higher accuracy at a substantially reduced computational cost.

Pan, Bing; Wang, Bo; Wu, Dafang; Lubineau, Gilles



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


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



Incoherent Digital Holographic Microscopy with Coherent and Incoherent Light  

NASA Astrophysics Data System (ADS)

Holography is an attractive imaging technique as it offers the ability to view a complete three-dimensional volume from one image. However, holography is not widely applied to the regime of fluorescence microscopy, because fluorescent light is incoherent and creating holograms requires a coherent interferometer system. We review two methods of generating digital Fresnel holograms of three-dimensional microscopic specimens illuminated by incoherent light. In the first method, a scanning hologram is generated by a unique scanning system in which Fresnel zone plates (FZP) are created by a coherently illuminated interferometer. In each scanning period, the system produces an on-axis Fresnel hologram. The twin image problem is solved by a linear combination of at least three holograms taken with three FZPs with different phase values. The second hologram reviewed here is the Fresnel incoherent correlation hologram. In this motionless holographic technique, light is reflected from the 3-D specimen, propagates through a spatial light modulator (SLM), and is recorded by a digital camera. Three holograms are recorded sequentially, each for a different phase factor of the SLM function. The three holograms are superposed in the computer, such that the result is a complex-valued Fresnel hologram that does not contain a twin image. When these two types of hologram are reconstructed in the computer, the 3-D properties of the specimen are revealed.

Rosen, Joseph; Brooker, Gary


3D holographic printer: fast printing approach.  


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



Holographic entanglement entropy of nonlocal field theories  

NASA Astrophysics Data System (ADS)

We study the holographic entanglement entropy of nonlocal field theories at both extremality and finite temperature. The gravity duals, constructed by Nozaki et al. [J. High Energy Phys. 10 (2012) 193], are characterized by a parameter w. Both the zero-temperature backgrounds and the finite-temperature counterparts are exact solutions of Einstein-Maxwell-dilaton theory. For the extremal case we consider the examples where the entangling regions are a strip and a sphere. We find that the leading-order behavior of the entanglement entropy always exhibits a volume law when the size of the entangling region is sufficiently small. We also clarify the condition under which the next-to-leading-order result is universal. For the finite-temperature case we obtain analytic expressions in both the high-temperature and low-temperature limits. In the former case the leading-order result approaches the thermal entropy, while the finite contribution to the entanglement entropy at extremality can be extracted by taking the zero-temperature limit in the latter case. Moreover, we observe some peculiar properties of the holographic entanglement entropy when w=1.

Pang, Da-Wei



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.



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

Microsoft Academic Search

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

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



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.



Indeterminacy of holographic quantum geometry  

SciTech Connect

An effective theory based on wave optics is used to describe indeterminacy of position in holographic spacetime with a UV cutoff at the Planck scale. Wave functions describing spacetime positions are modeled as complex disturbances of quasimonochromatic radiation. It is shown that the product of standard deviations of two position wave functions in the plane of a holographic light sheet is equal to the product of their normal separation and the Planck length. For macroscopically separated positions the transverse uncertainty is much larger than the Planck length, and is predicted to be observable as a 'holographic noise' in relative position with a distinctive shear spatial character, and an absolutely normalized frequency spectrum with no parameters once the fundamental wavelength is fixed from the theory of gravitational thermodynamics. The spectrum of holographic noise is estimated for the GEO600 interferometric gravitational-wave detector and is shown to approximately account for currently unexplained noise between about 300 and 1400 Hz. In a holographic world, this result directly and precisely measures the fundamental minimum interval of time.

Hogan, Craig J. [University of Chicago and Fermilab (United States)



Holographic Adaptive Optics  

NASA Astrophysics Data System (ADS)

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

Andersen, G.


Mean Platelet Volume Reflect Hematopoietic Potency and Correlated Blood Group O in Cord Blood from Healthy Newborn  

PubMed Central

We evaluated the relationship between mean platelet volume (MPV) and characteristics of 10,577 cord blood (CB) units in a public CB bank in Korea. Blood group O has the highest MPV (P = 0.002). MPV correlated with CB volume (r = 0.121), Hb (r = 0.377), WBC (r = 0.111), TNCs (r = 0.110), CD34+ cell (r = 0.174), CD34+ cells/TNCs (r = 0.157), gestational age (r = ?0.102), and birth weight (r = 0.023); (P < 0.001 in all). MPV may be one of the useful decision parameters of process priority in CB bank.

Lee, Hye Ryun; Park, Jeong Su; Shin, Sue; Roh, Eun Youn; Yoon, Jong Hyun; Song, Eun Young; Kim, Byung Jae; Chang, Ju Young



Tree-Bole Volume Estimation on Standing Pine Trees Using Cascade Correlation Artificial Neural Network Models  

Microsoft Academic Search

Total tree volume estimation is an integral part of forest growth and yield forecasting. Complex formulae are used to estimate bole volume by section, based on relationships proposed by Huber, Smalian and Newton. All these relationships require many measurements of bole diameters at certain heights that are difficult to obtain on standing trees especially when diameter measurements have to be

M. J. Diamantopoulou



Correlation between high-sensitivity C-reactive protein and brain gray matter volume in healthy elderly subjects.  


Although elevated serum high-sensitivity C-reactive protein (hsCRP) is related to atherosclerosis, brain infarction, and cognitive decline, it has not been clarified whether increased hsCRP is associated with the decline in brain gray matter volume. Therefore, the purpose of this study was to determine the relationship between hsCRP levels and brain regional gray matter volume using brain magnetic resonance imaging (MRI) data from 109 community-dwelling healthy elderly subjects. Brain MRIs were processed with voxel-based morphometry using a custom template by applying diffeomorphic anatomical registration using the exponentiated lie algebra (DARTEL) procedure. We found a significant negative correlation between regional gray matter volume of the posterior and lateral aspects of the left temporal cortex and hsCRP level after adjusting for age, gender, and intracranial volume. Our results suggest that subjects who have mild inflammation related to arteriosclerosis have decreased regional gray matter volume in the posterior and lateral aspects of the left temporal cortex. Thus, preventing the progression of arteriosclerosis may be important for preventing a decrease in gray matter volume in healthy elderly subjects. PMID:22438310

Taki, Yasuyuki; Thyreau, Benjamin; Kinomura, Shigeo; Sato, Kazunori; Goto, Ryoi; Wu, Kai; Kakizaki, Masako; Tsuji, Ichiro; Kawashima, Ryuta; Fukuda, Hiroshi



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



Holographic holes in higher dimensions  

NASA Astrophysics Data System (ADS)

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

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



Holographic films from carotenoid pigments  

NASA Astrophysics Data System (ADS)

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

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



Holographic Technidilaton and LHC Searches  

NASA Astrophysics Data System (ADS)

The holographic techni-dilaton is a parametrically light composite scalar appearing in the spectrum of certain strongly-coupled models of electroweak symmetry breaking built within the context of gauge-gravity dualities. I focus on particular subclasses of such models, both in the rigorous top-down approach to holography, as well as in the phenomenological bottom-up approach. I review the calculation of the mass of such a light scalar state. I briefly discuss some phenomenological features emerging in bottom-up models, and the implications for these models of the current LHC measurements of the couplings of the recently discovered scalar with mass of approximately 125-126 GeV. I summarize the present status of development of top-down holographic models of holographic walking technicolor related to the truncation of Type-IIB supergravity on T1,1.

Piai, Maurizio


Instant holographic portrait printing system  

NASA Astrophysics Data System (ADS)

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 stereogram printer is designed for easy operation under non-laboratory conditions, an anti-vibration table or a dark room is not required. We describe several key technologies as well as a practical method for evaluating the image quality produced by one-step hologram printers.

Shirakura, Akira; Kihara, Nobuhiro; Baba, Shigeyuki



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



Stellar spectroscopy: Fermions and holographic Lifshitz criticality  

NASA Astrophysics Data System (ADS)

Electron stars are fluids of charged fermions in Anti-de Sitter spacetime. They are candidate holographic duals for gauge theories at finite charge density and exhibit emergent Lifshitz scaling at low energies. This paper computes in detail the field theory Green's function G R( ?,k) of the gauge-invariant fermionic operators making up the star. The Green's function contains a large number of closely spaced Fermi surfaces, the volumes of which add up to the total charge density in accordance with the Luttinger count. Excitations of the Fermi surfaces are long lived for ? ? k z. Beyond ? ˜ k z the fermionic quasiparticles dissipate strongly into the critical Lifshitz sector. Fermions near this critical dispersion relation give interesting contributions to the optical conductivity.

Hartnoll, Sean A.; Hofman, Diego M.; Vegh, David



Single port access holographic particle image velocimetry  

SciTech Connect

An optical system, which requires only a single optical window mounted on a test volume, is proposed for holographic particle image velocimetry (HPIV). The optical system is a derivative of the double-exposure, double-reference-beam, off-axis HPIV system, but the innovative idea behind the system is to use back scattered light from the particles as the object wave. A 45{degree} beam splitter inserted in front of the window serves to admit the illuminating beam and extract the back scattered light. This concept can be of great engineering interest because optical access is often limited to one window in practical devices. The preliminary results of the technique appear quite promising, with current studies aimed at defining the optical resolution capabilities.

Woodruff, S.D.; Richards, G.A. [USDOE Morgantown Energy Technology Center, WV (United States); Cha, D.J. [National Research Council, Washington, DC (United States)



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.

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



Numerical reconstruction of full parallax holographic stereograms  

NASA Astrophysics Data System (ADS)

Holographic printers based on holographic stereograms are constantly gaining popularity. A holographic stereogram is recorded using 2D images of the 3D object or scene that are captured from multiple perspectives. Separation of capture and recording steps as well as checking of quality of the achieved 3D representation requires replaying of the composed holographic stereogram by computer. This paper presents a simulator which, as a first step, builds a full parallax holographic stereogram from the perspective images and, as a second step, reconstructs the hologram numerically for any viewer location by using a reconstruction algorithm proposed in the paper. To check the performance of the simulator we made a holographic stereogram of a test 3D object from images acquired by a virtual re-centering camera which was translated along a virtual camera track and compared the result from the numerical reconstruction with the optical reconstruction from the printed holographic stereogram of the same object. [Figure not available: see fulltext.

Park, Jiyung; Stoykova, Elena; Kang, Hoonjong; Hong, Sunghee; Lee, Seunghyun; Jung, Kwangmo



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



Holographic f( T) gravity model  

NASA Astrophysics Data System (ADS)

We try to study the corresponding relation between f( T) gravity and holographic dark energy (HDE). A kind of energy density from f( T) is introduced which has the same role as HDE density. A f( T) model according to the HDE model is calculated. We find out a torsion scalar T based on the scalar factor is assumed by Capoziello et al. (Phys. Lett. B 639:135, 2006). The effective torsion equation of state, deceleration parameter of the holographic f( T)-gravity model are calculated.

Aghamohammadi, A.



Glueball decay in holographic QCD  

SciTech Connect

Using holographic QCD based on D4-branes and D8-anti-D8-branes, we have computed couplings of glueballs to light mesons. We describe glueball decay by explicitly calculating its decay widths and branching ratios. Interestingly, while glueballs remain less well understood both theoretically and experimentally, our results are found to be consistent with the experimental data for the scalar glueball candidate f{sub 0}(1500). More generally, holographic QCD predicts that decay of any glueball to 4{pi}{sup 0} is suppressed, and that mixing of the lightest glueball with qq mesons is small.

Hashimoto, Koji [Institute of Physics, the University of Tokyo, Komaba, Tokyo 153-8902 (Japan); Tan, C.-I [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States); Terashima, Seiji [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)



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.



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.



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.



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


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



Volume overload correlates with cardiovascular risk factors in patients with chronic kidney disease.  


Volume overload is a predictor of mortality in dialysis patients. However, the fluid status of patients with chronic kidney disease (CKD) but not yet on dialysis has not been accurately characterized. We used the Body Composition Monitor, a multifrequency bioimpedance device, to measure the level of overhydration in CKD patients, focusing on the association between overhydration and cardiovascular disease risk factors. Overhydration was the difference between the amount of extracellular water measured by the Body Composition Monitor and the amount of water predicted under healthy euvolemic conditions. Volume overload was defined as an overhydration value at and above the 90th percentile for the normal population. Of the 338 patients with stages 3-5 CKD, only 48% were euvolemic. Patients with volume overload were found to use significantly more antihypertensive medications and diuretics but had higher systolic blood pressures and an increased arterial stiffness than patients without volume overload. In a multivariate analysis, male sex, diabetes, pre-existing cardiovascular disease, systolic blood pressure, serum albumin, TNF-?, and proteinuria were independently all associated with overhydration. Thus, volume overload is strongly associated with both traditional and novel risk factors for cardiovascular disease. Bioimpedance devices may aid in clinical assessment by helping to identify a high-risk group with volume overload among stages 3-5 CKD patients. PMID:24025647

Hung, Szu-Chun; Kuo, Ko-Lin; Peng, Ching-Hsiu; Wu, Che-Hsiung; Lien, Yu-Chung; Wang, Yi-Chun; Tarng, Der-Cherng



Photopolymer holographic recording material  

NASA Astrophysics Data System (ADS)

Photopolymers are promising materials for use in holography. They have many advantages, such as ease of preparation, and are capable of efficiencies of up to 100%. A disadvantage of these materials is their inability to record high spatial frequency gratings when compared to other materials such as dichromated gelatin and silver halide photographic emulsion. Until recently, the drop off at high spatial frequencies of the material response was not predicted by any of the diffusion based models available. It has recently been proposed that this effect is due to polymer chains growing away from their initiation point and causing a smeared profile to be recorded. This is termed a non-local material response. Simple analytic expressions have been derived using this model and fits to experimental data have allowed values to be estimated for material parameters such as the diffusion coefficient of monomer, the ratio of polymerisation rate to diffusion rate and the distance that the polymer chains spread during holographic recording. The model predicts that the spatial frequency response might be improved by decreasing the mean polymer chain lengths and/or by increasing the mobility of the molecules used in the material. The experimental work carried out to investigate these predictions is reported here. This work involved (a) the changing of the molecular weights of chemical components within the material (dyes and binders) and (b) the addition of a chemical retarder in order to shorten the polymer chains, thereby decreasing the extent of the non-local effect. Although no significant improvement in spatial frequency response was observed the model appears to offer an improved understanding of the operation of the material.

Lawrence, J. R.; O'Neill, F. T.; Sheridan, J. T.


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



Efficient generation of holographic news ticker in holographic 3DTV  

NASA Astrophysics Data System (ADS)

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

Kim, Seung-Cheol; Kim, Eun-Soo




NSDL National Science Digital Library

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

Christmann, Edwin P.; Badgett, John L.



Dynamic holographic imaging of the beating human heart  


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



Holographic diffraction gratings recording in organically modified silica gels  

NASA Astrophysics Data System (ADS)

The silica gel-methyl methacrylate organically modified ceramic is proposed for recording of volume holograms. Both low-spatial-frequency (54 line pairs /mm-1 ) and high-spatial-frequency (1400 line pairs /mm-1 ) holographic gratings were successfully recorded in the medium by interference of two coherent beams of 351.1-nm wavelength. High diffraction efficiencies (93%) and extremely low absorption and scattering coefficients were measured during the holographic reconstruction by a 632.8-nm He-Ne beam. The optimum UV recording exposure was \\similar 3J cm -2 . A grating refractive-index modulation amplitude of 1.1 \\times 10-4 was achieved. Virtually no changes in diffraction efficiency were observed after thermal-heating, light-curing, and long-term-aging experiments.

Cheben, P.; Belenguer, T.; Nuñez, A.; del Monte, F.; Levy, D.



Holographic gunsight: the next generation  

NASA Astrophysics Data System (ADS)

Holographic gunsight was first conceived in the 1970s and prototypes were fabricated using a He-Ne laser as the illuminating source. The laser source was too costly and fragile and these prototype units were too bulky to be viable as a commercial product. With the advent of low cost laser diodes, EOTech introduced into the commercial market a compact holographic gunsight for small arms in 1996 which has since become one of the most popular gunsight in the U.S. and in Europe. In this paper, the design of the second generation holographic gunsight is described. The optical path travels predominantly in the vertical direction which reduces the length and the weight of the sight by a third. The optical design challenges include the generation of a stable holographic image with changes in the laser emission wavelength, circularization of the laser elliptical beam profile, and the production of high quality optics at low cost. The opto-mechanical design challenges include very fine angular adjustments, stability over large temperature range and the ability to withstand the recoil of powerful handguns.

Tai, Anthony M.; Sieczka, Eric J.; Upatnieks, Juris



Dynamic digital holographic wavelength filtering  

Microsoft Academic Search

This paper describes the theory and results of a new generic technology for use in optical telecommunications and wavelength division multiplexing (WDM): dynamic digital holographic wavelength filtering. The enabling component is a polarization-insensitive ferroelectric liquid crystal (FLC) spatial light modulator (SLM) in conjunction with a highly wavelength-dispersive fixed diffractive element. The technology has been used to perform demultiplexing of single

Michael C. Parker; Adam D. Cohen; Robert J. Mears



Generalized holographic dark energy model  

NASA Astrophysics Data System (ADS)

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

Jamil, Mubasher; Farooq, M. Umar; Rashid, Muneer Ahmad



Holographic Twyman-Green Interferometer  

NASA Technical Reports Server (NTRS)

Off-axis Fresnel zone plate used to obtain fringe visibility close to unity. Holographic Twyman-Green Interferometer (HTG) employs off-axis Fresnel zone plate (OFZP) as beam splitter and beam diverger in place of two separate elements that perform those functions in conventional TwymanGreen interferometer.

Chen, C. W.; Wyant, J. C.; Breckinridge, J. B.



Generalized holographic dark energy model  

Microsoft Academic Search

In this paper, the model of the holographic Chaplygin gas has been extended to two general cases: first the case of a modified\\u000a variable Chaplygin gas and second the case of the viscous generalized Chaplygin gas. The dynamics of the model is expressed\\u000a by the use of scalar fields and scalar potentials.

Mubasher Jamil; M. Umar Farooq; Muneer Ahmad Rashid



Universality class of holographic superconductors  

SciTech Connect

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

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



Holographic dark-energy models  

NASA Astrophysics Data System (ADS)

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

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



Holographic superconductivity in M theory.  


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

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



Holographic studies of photoinduced anisotropy in molecular glassy films containing diphenylamine azochromophores  

NASA Astrophysics Data System (ADS)

Photoinduced anisotropy (PA) is experimentally studied in three molecular glassy films synthesized in our Faculty and containing diphenylamine based azochromophores {4-((4-nitrophenyl)diazenyl)-N-(4-((4-nitrophenyl)diazenyl)phenyl)-N-(2-trityloxy)ethyl) benzeneamine (shortly K-D-24), 4-((2-chloro-4-tritylphenyl)diazenyl)-N-(4-((2-chloro-4-tritylphenyl)diazenyl)phenyl)-N-(2-(trityloxy)ethyl)benzenamine (shortly K-D-25), 4,4'-(2-(trityloxy)ethylazanediyl)bis(4,1-phenylene)bis(diazene-2,1-diyl)dibenzonitrile (shortly K-D-32) } and, for comparison, in an a-As2S3 film. Holographic method enabling simultaneous measurements of s- and p-polarized diffracted light powers was applied in both transmission and reflection modes. Holographic grating recording with the period of 2 ?m was made by two equally strong 532 nm p- polarized laser beams with total light intensity of 0.81 W/cm2. The readout was made by 633 nm circularly polarized beam, and the s- and p-polarized components of diffracted light were separated by polarization beam splitter prism. PA was characterized by diffracted power difference (DPD), Ps - Pp, and by anisotropy contrast A = (ns - np)/(ns + np), ns and np being the diffraction efficiencies for s- and p-polarized light. DPD exhibited markedly different kinetic behaviour in transmission and reflection modes. There was a negative minimum in transmission mode in all samples, and a growth with oscillations up to saturation in reflection mode. Small initial DPD maxima were specific to a-As2S3 film. The highest PA was found in K-D-24 film in transmission mode (A=-0.23) and in K-D-25 film in reflection mode (A=0.49). Holographic recording efficiency and PA do not correlate. In our opinion, PA in transmission mode of molecular glasses is due to the photoinduced volume processes including trans-cis photoisomerization, chromophore orientation and mechanical stress modulation. In the case of a-As2S3 film these photoinduced volume processes include photoinduced structural changes, D-centre orientation and, again, mechanical stress modulation. All these processes lead to a photoinduced birefringence. Surface relief grating recording and polarization-dependent reflection are responsible for diffractive anisotropy in reflection mode.

Ozols, A.; Kokars, V.; Augustovs, P.; Traskovskis, K.; Saharov, D.



Reduced Limbic and Hypothalamic Volumes Correlate with Bone Density in Early Alzheimer's Disease  

PubMed Central

Accelerated bone loss is associated with Alzheimer’s disease (AD). Although the central nervous system plays a direct role in regulating bone mass, primarily through the actions of the hypothalamus, there is little work investigating the possible role of neurodegeneration in bone loss. In this cross-sectional study, we examined the association between bone mineral density (BMD) and neuroimaging markers of neurodegeneration (i.e., global and regional measures of brain volume) in early AD and non-demented aging. Fifty-five non-demented and 63 early AD participants underwent standard neurological and neuropsychological assessment, structural MRI scanning, and dual energy x-ray absorptiometry. In early AD, voxel-based morphometry analyses demonstrated that low BMD was associated with low volume in limbic grey matter (GM) including the hypothalamus, cingulate, and parahippocampal gyri and in the left superior temporal gyrus and left inferior parietal cortex. No relationship between BMD and regional GM volume was found in non-demented controls. The hypothesis-driven region of interest analysis further isolating the hypothalamus demonstrated a positive relationship between BMD and hypothalamic volume after controlling for age and gender in the early AD group but not in non-demented controls. These results demonstrate that lower BMD is associated with lower hypothalamic volume in early AD, suggesting that central mechanisms of bone remodeling may be disrupted by neurodegeneration.

Loskutova, Natalia; Honea, Robyn A.; Brooks, William M.; Burns, Jeffrey M.



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

NASA Technical Reports Server (NTRS)

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



Nonnegative Least-Correlated Component Analysis for Separation of Dependent Sources by Volume Maximization  

Microsoft Academic Search

Although significant efforts have been made in developing nonnegative blind source separation techniques, accurate separation of positive yet dependent sources remains a challenging task. In this paper, a joint correlation function of multiple signals is proposed to reveal and confirm that the observations after nonnegative mixing would have higher joint correlation than the original unknown sources. Accordingly, a new nonnegative

Fa-Yu Wang; Chong-Yung Chi; Tsung-Han Chan; Yue Wang



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

Microsoft Academic Search

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




Neural correlates of the 'good life': eudaimonic well-being is associated with insular cortex volume  

PubMed Central

Eudaimonic well-being reflects traits concerned with personal growth, self-acceptance, purpose in life and autonomy (among others) and is a substantial predictor of life events, including health. Although interest in the aetiology of eudaimonic well-being has blossomed in recent years, little is known of the underlying neural substrates of this construct. To address this gap in our knowledge, here we examined whether regional gray matter (GM) volume was associated with eudaimonic well-being. Structural magnetic resonance images from 70 young, healthy adults who also completed Ryff’s 42-item measure of the six core facets of eudaimonia, were analysed with voxel-based morphometry techniques. We found that eudaimonic well-being was positively associated with right insular cortex GM volume. This association was also reflected in three of the sub-scales of eudaimonia: personal growth, positive relations and purpose in life. Positive relations also showed a significant association with left insula volume. No other significant associations were observed, although personal growth was marginally associated with left insula, and purpose in life exhibited a marginally significant negative association with middle temporal gyrus GM volume. These findings are the first to our knowledge linking eudaimonic well-being with regional brain structure.

Kanai, Ryota; Rees, Geraint; Bates, Timothy C.



Neural correlates of the 'good life': eudaimonic well-being is associated with insular cortex volume.  


Eudaimonic well-being reflects traits concerned with personal growth, self-acceptance, purpose in life and autonomy (among others) and is a substantial predictor of life events, including health. Although interest in the aetiology of eudaimonic well-being has blossomed in recent years, little is known of the underlying neural substrates of this construct. To address this gap in our knowledge, here we examined whether regional gray matter (GM) volume was associated with eudaimonic well-being. Structural magnetic resonance images from 70 young, healthy adults who also completed Ryff's 42-item measure of the six core facets of eudaimonia, were analysed with voxel-based morphometry techniques. We found that eudaimonic well-being was positively associated with right insular cortex GM volume. This association was also reflected in three of the sub-scales of eudaimonia: personal growth, positive relations and purpose in life. Positive relations also showed a significant association with left insula volume. No other significant associations were observed, although personal growth was marginally associated with left insula, and purpose in life exhibited a marginally significant negative association with middle temporal gyrus GM volume. These findings are the first to our knowledge linking eudaimonic well-being with regional brain structure. PMID:23512932

Lewis, Gary J; Kanai, Ryota; Rees, Geraint; Bates, Timothy C



The AMRL Anthropometric Data Bank Library. Volume V. U.S. Correlations.  

National Technical Information Service (NTIS)

Correlation matrices based on data from USAF anthropometric surveys of women (1968, 127 variables), flying personnel (1950, 128 variables; 1967, 190 variables), and basic trainees (1965, 161 variables); a U.S. Army survey of women separatees (1946, 60 var...

C. E. Clauser P. Kikta



Nonnegative Least-correlated Component Analysis for Separation of Dependent Sources by Volume Maximization  

Microsoft Academic Search

Although significant efforts have been made in developing non-negative blind source separation techniques, accurate separation of positive yet dependent sources remains a challenging task. In this paper, a joint correlation function of multiple signals is proposed to reveal and confirm that the observations after non-negative mixing would have higher joint correlation than the original unknown sources. Accordingly, a new non-negative

Fa-Yu Wang; Chong-Yung Chi; Tsung-Han Chan; Yue Wang


Correlation of breast dose heterogeneity with breast size using 3D CT planning and dose-volume histograms.  


The aim of this study was to evaluate the effect of breast size on dose heterogeneity. Twenty women underwent a planning CT scan of the thorax. A three-dimensional treatment plan was devised for each patient using a standard technique of isocentric medial and lateral wedged tangential fields. Three-dimensional dose distributions were derived using an equivalent path length (EPL) inhomogeneity correction and cumulative dose-volume histogram (DVH) data calculated for the breast. Analysis of the DVHs for each patient reveals that 0.2-23.8% of the breast received an absorbed dose outside the desired 95-105% of that prescribed at the isocentre. The degree of dose heterogeneity was most strongly correlated with breast volume (r = 0.70, 95% confidence interval (C.I.) 0.37-0.87). There was also a positive correlation for breast dose heterogeneity versus brassière (bra) cup size (Spearman rank correlation rho = 0.62), breast area (r = 0.39, 95% C.I. -0.06-0.71) and chest wall separation (r = 0.31, 95% C.I. -0.15-0.66). We conclude that breast size is an important determinant of dose heterogeneity within the breast. PMID:7631027

Neal, A J; Torr, M; Helyer, S; Yarnold, J R



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



Real-time holographic pattern recognition with bacteriorhodopsin films  

NASA Astrophysics Data System (ADS)

The biological photochrome bacteriorhodopsin (BR) has attractive photophysical properties which allow its use as the photoactive component for dynamic recording media for optical applications. Purple membrane (PM) patches, which contain BR in a two-dimensional crystalline lattice, are isolated from Halobacterium halobium. Polymeric films with embedded PM are well suited reversible media for holographic recording. In addition, artificial derivatives of BR with improved optical properties can be generated by genetic methods and isolated from the mutated halobacterial strains. The high reversibility (> 106 record/erase cycles), the fast timescale of its photoconversions (fs - ms), and the high resolution (> 5000 lines/mm) make these films suitable media for real-time holographic applications. A dual-axis joint-Fourier-transform correlator is described with two liquid crystal television screens as input devices and a BR-film as active holographic material in the Fourier plane. The experimental data presented demonstrate that this system is capable of processing two independent video signals in real-time with a signal-to-noise ratio of 45 dB. The polarization recording properties of BR-films offer an efficient method to separate the correlation signal from scattered light.

Hampp, Norbert; Thoma, Ralph; Braeuchle, Christoph R.; Oesterhelt, Dieter



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


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



Collinear holographic data storage system  

NASA Astrophysics Data System (ADS)

Holographic data storage system is a promising candidate of the next-generation of storage equipment. However, conventional technologies (called 2-axis holography) still have essential issues for commercialization of products. In this paper, we introduce the collinear holography that can produce a small, practical data storage system more easily than conventional 2-axis holography. In this technology the information and reference beams are displayed co-axially by the same SLM. With this unique configuration the optical pickup can be placed on one side of the recording media. The special media structure uses a pre-formatted reflective layer for the focus/tracking servo and for reading address information. It also uses a dichroic mirror interlayer for detecting holographic recording information without interfering with the preformatted information. A 2-dimensional digital page data format is used and the shift-multiplexing method is employed to increase recording density.

Tan, Xiaodi; Lin, Xiao; Wu, Anan



Holographic type II Goldstone bosons  

NASA Astrophysics Data System (ADS)

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

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



Holographic Fabry-Perot spectrometer.  


We propose a spectrum analyzer based on the properties of a hologram recorded with the field transmitted by a Fabry-Perot etalon. The spectral response of this holographic Fabry-Perot spectrometer (HFPS) is analytically investigated in the paraxial approximation and compared with a conventional Fabry-Perot etalon of similar characteristics. We demonstrate that the resolving power is twice increased and the free spectral range (FSR) is reduced to one-half. The proposed spectrometer could improve the operational performance of the etalon because it can exhibit high efficiency and it would be insensible to environmental conditions such as temperature and vibrations. Our analysis also extends to another variant of the HFPS based on holographic multiplexing of the transmitted field of a Fabry-Perot etalon. This device increases the FSR, keeping the same HFPS performance. PMID:21326457

Martínez-Matos, O; Rodrigo, José A; Vaveliuk, P; Calvo, M L



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



Holographic recording materials - A review  

NASA Technical Reports Server (NTRS)

Holographic recording materials in current use are examined along with a few of their applications. Some experimental media are also studied. No effort is made to rank the commercial materials, since satisfactory results can be obtained with any of them. The discussion covers silver halide plates and films, photoresists, thermoplastics, photopolymers, dichromated gelatin, photochromic materials, electrooptical crystals, styryl free radical film, and TEP film. A convenient summation of some material properties is presented in tabular form.

Kurtz, R. L.; Owen, R. B.



Holographic construction of technicolor theory  

Microsoft Academic Search

We construct a dual description of technicolor theory based on the D4\\/D8 brane configuration. A strongly-coupled technicolor theory is identified as the effective theory on D-branes, and from the gauge\\/gravity correspondence, we explore the weakly-coupled holographic description of dynamical electroweak symmetry breaking. It is found from the D-brane probe action that the masses of W and Z bosons are given

Takayuki Hirayama; Koichi Yoshioka



Constructive Use of Holographic Projections  

NASA Astrophysics Data System (ADS)

Revisiting the old problem of existence of interacting models of QFT with new conceptual ideas and mathematical tools, one arrives at a novel view about the nature of QFT. The recent success of algebraic methods in establishing the existence of factorizing models suggests new directions for a more intrinsic constructive approach beyond Lagrangian quantization. Holographic projection simplifies certain properties of the bulk theory and hence is a promising new tool for these new attempts.

Schroer, Bert


Holographic evolution of entanglement entropy  

Microsoft Academic Search

We study the evolution of entanglement entropy in a 2-dimensional equilibration process that has a holographic description\\u000a in terms of a Vaidya geometry. It models a unitary evolution in which the field theory starts in a pure state, its vacuum,\\u000a and undergoes a perturbation that brings it far from equilibrium. The entanglement entropy in this set up provides a measurement

Javier Abajo-Arrastia; João Aparício; Esperanza López



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)



Holographic gunsights for small arms  

NASA Astrophysics Data System (ADS)

Holographic gunsights were first demonstrated in the mid 1970s by researchers at the Environmental Research Institute of Michigan (ERIM) under contracts with the Air Force and the Army. The sights utilized He-Ne gas lasers and were designed for use with large weapons systems. With the advent of low cost visible laser diode, ERIM formed a new company, EOTech, to develop, manufacture and market a holographic gun sight for small arms. A hologram is used to reconstruct the image of a reticle pattern that appears at the target plane. Unlike red-dot sights, virtually any reticle pattern, 2D or 3D, can be formed. The design challenges include an opto-mechanical package that is compact, light weight and low cost which can withstand recoils up to 4,000 Gs and provide fine elevation/windage pointing adjustments, and optics that are aberration-free and stable over a wide temperature range. Manufacturing challenges include the mass production of high quality holographic optics at low cost and the precision alignment of the very low f/number optics.

Tai, Anthony M.; Sieczka, Eric J.; Radler, Richard; Upatnieks, Juris



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



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



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


Prior studies have examined differences in brain volume between patients with post-traumatic stress disorder (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 magnetic resonance imaging (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 volumes of the 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



Alignment of 700 globin sequences: extent of amino acid substitution and its correlation with variation in volume.  

PubMed Central

Seven-hundred globin sequences, including 146 nonvertebrate sequences, were aligned on the basis of conservation of secondary structure and the avoidance of gap penalties. Of the 182 positions needed to accommodate all the globin sequences, only 84 are common to all, including the absolutely conserved PheCD1 and HisF8. The mean number of amino acid substitutions per position ranges from 8 to 13 for all globins and 5 to 9 for internal positions. Although the total sequence volumes have a variation approximately 2-3%, the variation in volume per position ranges from approximately 13% for the internal to approximately 21% for the surface positions. Plausible correlations exist between amino acid substitution and the variation in volume per position for the 84 common and the internal but not the surface positions. The amino acid substitution matrix derived from the 84 common positions was used to evaluate sequence similarity within the globins and between the globins and phycocyanins C and colicins A, via calculation of pairwise similarity scores. The scores for globin-globin comparisons over the 84 common positions overlap the globin-phycocyanin and globin-colicin scores, with the former being intermediate. For the subset of internal positions, overlap is minimal between the three groups of scores. These results imply a continuum of amino acid sequences able to assume the common three-on-three alpha-helical structure and suggest that the determinants of the latter include sites other than those inaccessible to solvent.

Kapp, O. H.; Moens, L.; Vanfleteren, J.; Trotman, C. N.; Suzuki, T.; Vinogradov, S. N.



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.



Estimation of Truck Traffic Volume from Single Loop Detectors Using Lane-to-Lane Speed Correlation  

Microsoft Academic Search

An algorithm for real time estimation of truck traffic in multi-lane freeway is proposed. The algorithm uses data from single loop detectors-the most widely installed surveillance technology for urban freeways in the US. The algorithm works for those freeway locations that have a truck-free lane, and exhibit high lane-to-lane speed correlation. These conditions are met by most urban freeway locations.

Jaimyoung Kwon; Pravin Varaiya; Alexander Skabardonis



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



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

PubMed Central

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.

Ivannikov, Maxim V.; Sugimori, Mutsuyuki; Llinas, Rodolfo R.



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



The Holographic Screen at Low Temperatures  

NASA Astrophysics Data System (ADS)

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 spacetime with the Milgrom acceleration in MOND.

Kiselev, V. V.; Timofeev, S. A.


A Blazed Holographic Concave Grating for Monochromators  

Microsoft Academic Search

The theory of blazed holographic gratings given in a previous paper is applied to the design of a blazed holographic aberration-corrected spherical concave grating. Two solution types are found which cover different ranges of blaze wavelength and aberration. The use of the refractive indices of the substrate, and the medium in front of the photoresist, as optimising parameters is demonstrated.

P. Lehmann



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



Achromatic Holographic Lithography in the Deep Ultraviolet,  

National Technical Information Service (NTIS)

Holographic lithography, in which the interference pattern of two coherent waves is used to expose a resist film, is the preferred technique for producing large-area gratings with low distortion. The spatial period of a pattern produced by holographic lit...

E. H. Anderson, K. Komatsu, H. I. Smith



Web service for digital holographic video processing  

NASA Astrophysics Data System (ADS)

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

Ekimov, Dmitry; Mäkynen, Anssi



Correlation of Volume Transfer Coefficient Ktrans with Histopathologic Grades of Gliomas  

PubMed Central

Purpose To evaluate the roles of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and optimum tracer kinetic parameters in the noninvasive grading of the glial brain tumors with histopathological grades (I–IV). Materials and Methods Twenty eight patients with histopathologically graded gliomas were imaged. Images with five flip angles were acquired before injection of gadolinium-DTPA and were processed to calculate the T1 value of each regions of interest (ROI). All the DCE-MRI data acquired during the injection were processed based on the MRI signal and pharmacokinetic models to establish concentration-time curves in the ROIs drawn within the tumors, counterlateral normal areas, and area of the individual artery input functions (iAIF) of each patient. A nonlinear least square fitting method was used to obtain tracer kinetic parameters. Kruskal-Wallis H-test and Mann-Whitney U-test were applied to these parameters in different histopathological grade groups for statistical differences (P<0.05). Results Volume transfer coefficient (Ktrans) and extravascular extracellular space volume fraction (Ve) calculated by using iAIFs can be used not only to distinguish the low (i.e., I and II) from the high (i.e., III and IV) grade gliomas (P(Ktrans) <0.001 and PVe<0.001), but also grade II from III (P(Ktrans) =0.016 and PVe=0.033). Conclusion Ktrans is the most sensitive and specific parameter in the noninvasive grading, distinguishing the high (III and IV) from the low (I and II) grade and high grade III from low grade II gliomas.

Zhang, Na; Zhang, Lijuan; Qiu, Bensheng; Meng, Li; Wang, Xiaoyi; Hou, Bob L.



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

PubMed Central

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

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



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



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



Ultrasound measurements of brain tissue pulsatility correlate with the volume of MRI white-matter hyperintensity.  


White-matter hyperintensity (WMH) is frequently seen in magnetic resonance imaging (MRI), but the complete physiopathology of WMH remains to be elucidated. In this study, we sought to determine whether there is an association between the maximum brain tissue displacement (maxBTD), as assessed by ultrasound, and the WMH, as observed by MRI. Nine healthy women aged 60 to 85 years underwent ultrasound and MRI assessments. We found a significant negative correlation between maxBTD and WMH (?=-0.86, P<0.001), suggesting a link between cerebral hypoperfusion and WMH. PMID:24714033

Ternifi, Redouane; Cazals, Xavier; Desmidt, Thomas; Andersson, Frédéric; Camus, Vincent; Cottier, Jean-Philippe; Patat, Frédéric; Remenieras, Jean-Pierre



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.



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

PubMed Central

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



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.



Correlating 2D NTSC gamut ratio to its 3D gamut volume  

NASA Astrophysics Data System (ADS)

The present study provides functions to correlate gamut size across different color spaces including 2D planes - (x,y) and (u',v') and 3D spaces - CIELAB, CIECAM02 JCh and QMh. All gamut size must be converted to NTSC gamut ratio before using the functions. As viewing conditions influence 3D gamut ratio significantly, predict 3D gamut ratio in high precision is not easy. However, the mean values, median values, standard deviations, and confidence intervals can be predicted accurately. In terms of viewing parameters, we can model them individually under IEC reference condition successfully, the resulted functions would be a good reference to derive more versatile functions to predict gamut ratio under complex viewing conditions.

Sun, Pei-Li



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



Application of the digital volume correlation technique for the measurement of displacement and strain fields in bone: a literature review.  


Digital volume correlation (DVC) provides experimental measurements of displacements and strains throughout the interior of porous materials such as trabecular bone. It can provide full-field continuum- and tissue-level measurements, desirable for validation of finite element models, by comparing image volumes from subsequent µCT scans of a sample in unloaded and loaded states. Since the first application of DVC for measurement of strain in bone tissue, subsequent reports of its application to trabecular bone cores up to whole bones have appeared within the literature. An "optimal" set of procedures capable of precise and accurate measurements of strain, however, still remains unclear, and a systematic review focussing explicitly on the increasing number of DVC algorithms applied to bone or structurally similar materials is currently unavailable. This review investigates the effects of individual parameters reported within individual studies, allowing to make recommendations for suggesting algorithms capable of achieving high accuracy and precision in displacement and strain measurements. These recommendations suggest use of subsets that are sufficiently large to encompass unique datasets (e.g. subsets of 500 µm edge length when applied to human trabecular bone cores, such as cores 10mm in height and 5mm in diameter, scanned at 15 µm voxel size), a shape function that uses full affine transformations (translation, rotation, normal strain and shear strain), the robust normalized cross-correlation coefficient objective function, and high-order interpolation schemes. As these employ computationally burdensome algorithms, researchers need to determine whether they have the necessary computational resources or time to adopt such strategies. As each algorithm is suitable for parallel programming however, the adoption of high precision techniques may become more prevalent in the future. PMID:24529357

Roberts, Bryant C; Perilli, Egon; Reynolds, Karen J



Hot Holographic Giant Loop  

NASA Astrophysics Data System (ADS)

We consider the Polyakov loop operator in finite temperature planar N = 4 supersymmetric Yang-Mills theory defined on a spatial S3 and in representations where the number of boxes in the Young Tableau k is large and scales so that kN remains finite in the large N limit. We review the argument that, in the de-confined phase of the gauge theory, and for symmetric representations with row Young tableau, there is a quantum phase transition in the expectation value of the Polyakov loop operator which occurs as the size of the representation is increased beyond a critical value of kN. We also argue that for completely antisymmetric representations with column tableau, there is no such phase transition. The AdS/CFT dual of such large representation loops are thought to be probe D-branes with k units of fundamental string charge dissolved in their world-volumes. Our results for both symmetric and antisymmetric representations are consistent with what is known about these branes on the thermal AdS black hole background.

Grignani, G.; Karczmarek, J. L.; Semenoff, G. W.



Holographic associative memory system using a thresholding microchannel spatial light modulator  

Microsoft Academic Search

Experimental implementation of a holographic optical associative memory system using a thresholding microchannel spatial light modulator (MSLM) is presented. The first part of the system is a joint transform correlator, in which a liquid crystal light valve is used as a square-law converter for the inner product of the addressing and input memories. The MSLM is used as an active

Q. W. Song; F. T. S. Yu



Method and apparatus for holographic processing  

NASA Technical Reports Server (NTRS)

A method and apparatus for holographically processing optical signals in a fiber-optic sensor system. In the present invention, holographic processors are utilized in various combinations with light sources, fiber-optic transmission means, sensors and detectors to provide low cost, compact, sensitive and accurate sensor systems. By means of the holographic processors of the present invention, the aforementioned sensor systems are used to monitor such physical parameters as temperature, pressure, flow-rate, and the like, and to provide output signal indications thereof that are compatible with digital receiving stations and immune to electro-magnetic interference, hazardous atmosphere, and the inimical effects of inadvertent intensity variation due to equipment vibration and the like. In one typical embodiment, a pair of holographic processors are employed in a color multiplex-demultiplex sensor system in which a first holographic processor is employed to color multiplex a sensor signal and a second holographic processor is employed to decode the color-multiplexed signal into a binary pattern that is then transmitted onto a set of photodetectors. In each of the embodiments of the invention disclosed, a unique geometrical orientation of a hologram is utilized to minimize spurious signal interference that would otherwise hamper or totally preclude the holographic processing.

Quick, William H. (Inventor); James, Kenneth A. (Inventor); Strahan, Virgil H. (Inventor)



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



Correlations between cerebellar and brain volumes, cognitive impairments, ApoE levels, and APOE genotypes in patients with AD and MCI.  


Due to the increasing incidence of Alzheimer's disease (AD), many studies have aimed to improve its diagnosis. Particular attention has been focused on measuring volumes of brain structures. Only few studies have investigated whether the cerebellar volume changes with the stage of dementia. It is controversial whether the serum apolipoprotein E (ApoE) level is an appropriate AD marker. This study was designed to clarify the significance of both cerebellar volume measurements and ApoE level measurements as markers of neurodegenerative changes. This study included 55 subjects with AD, 30 subjects with mild cognitive impairments (MCI), and a control group with 30 subjects. We measured the brain, cerebellum, and brain stem volumes with magnetic resonance imaging (MRI). We determined serum ApoE levels, APOE genotypes, and neuropsychological test scores. In the control group, we found that ApoE levels were significantly higher for subjects with the APOE 2/3 genotype than those with the 4/4 genotype. This finding may indicate that ApoE plays a protective role against AD development in subjects with the APOE 2/3 genotype. ApoE levels were not significantly different in patients with AD and MCI. No correlations were found between serum ApoE levels and Mini-Mental State Examination (MMSE) scores or the volumes of brain structures. This study could not confirm the appropriateness of the cerebellum volume as an early AD marker. Correlations were found between cerebellar volume, brain volume, and the MMSE scores. PMID:24117117

?ojkowska, Wanda; Witkowski, Grzegorz; Bednarska-Makaruk, Ma?gorzata; Wehr, Hanna; Sienkiewicz-Jarosz, Halina; Graban, A??a; Bochy?ska, Anna; Wi?niewska, Anna; Guga?a, Magdalena; S?awi?ska, Ksenia; Sawicka, Beata; Poniatowska, Renata; Ryglewicz, Danuta



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

NASA Astrophysics Data System (ADS)

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

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



Holographic technidilaton at 125 GeV  

NASA Astrophysics Data System (ADS)

We find that a holographic walking technicolor model has a limit (“conformal limit”) where the technidilaton (TD) becomes a massless Nambu-Goldstone boson of the scale symmetry with its nonzero finite decay constant F??0, which naturally realizes a light TD, say at 125 GeV, near the limit. In such a light TD case, we find that F? is uniquely determined by the technipion decay constant F? independently of the holographic parameters: F?/F??2NTF, with NTF being the number of technifermions. We show that the holographic TD is consistent with a new boson at 125 GeV recently discovered at the LHC.

Matsuzaki, Shinya; Yamawaki, Koichi



The Shear Viscosity of Holographic Superfluids  

NASA Astrophysics Data System (ADS)

We study the ratio of the shear viscosity to the entropy density for various holographic superfluids. For the s-wave case, the ratio has the universal value 1/(4?) as in various holographic models. For the p-wave case, there are two shear viscosity coefficients because of the anisotropic boundary spacetime, and one coefficient has the universal value. For the (p + ip)-wave case, the existing technique is not applicable since there is no tensor mode of metric perturbations which decouples from Yang-Mills perturbations. Our results indicate that the shear viscosity does not show a singular behavior at the critical point for holographic superfluids.

Natsuume, M.; Ohta, M.



Holographic baryons from oblate instantons  

NASA Astrophysics Data System (ADS)

We investigate properties of baryons in a family of holographic field theories related to the Sakai-Sugimoto model of holographic QCD. Starting with the N f = 2 Sakai-Sugimoto model, we truncate to a 5D Yang-Mills action for the gauge fields associated with the noncompact directions of the flavor D8-branes. We define a free parameter ? that controls the strength of this Yang-Mills term relative to the Chern-Simons term that couples the Abelian gauge field to the SU(2) instanton density. Moving away from ? = 0 should incorporate some of the effects of taking the Sakai-Sugimoto model away from large 't Hooft coupling ?. In this case, the baryon ground state corresponds to an oblate SU(2) instanton on the bulk flavor branes: the usual SO(4) symmetric instanton is deformed to spread more along the field theory directions than the radial direction. We numerically construct these anisotropic instanton solutions for various values of ? and calculate the mass and baryon charge profile of the corresponding baryons. Using the value ? = 2.55 that has been found to best fit the mesonic spectrum of QCD, we find a value for the baryon mass of 1.19 GeV, significantly more realistic than the value 1.60 GeV computed previously using an SO(4) symmetric ansatz for the instanton.

Rozali, Moshe; Stang, Jared B.; Van Raamsdonk, Mark



Holographic opto-fluidic microscopy  

PubMed Central

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

Bishara, Waheb; Zhu, Hongying; Ozcan, Aydogan



Holographic spectrograph for space telescope  

NASA Astrophysics Data System (ADS)

A spectrograph is described which is made with dual Holographic Optical Elements (HOEs) which are identical and parallel to each other. Both optics are collimating transmission HOEs with focal points that are at equal and opposite distances from each other. The identical HOEs are formed by the interference of a plane wave parallel to the grating plane with an off-axis spherical wave originating in the near-field. In playback, a spectrum can be formed from a point source radiator placed at the position of the recording spherical wave. If played back at an arbitrary wavelength other than the recording wavelength, the image exhibits coma. This spectrograph is intended for an unusual configuration where many nearly monochromatic sources of known wavelengths are separately positioned relative to the first HOE. The special application is in a space telescope capable of resolving spectra from habitable planets within 10 pc. HOEs of this type could be fabricated on membrane substrates with a low areal mass and stowable on rolls for insertion into the second Lagrange point. The intended application is for a 50 x 10 meter class primary objective holographic space telescope with 50 x 10 m HOEs in the spectrograph. We present a computer model of the spectrograph.. Experimental results are compared with predictions from theory. A single HOE is shown to perform over a wider bandwidth and is demonstrated.

Ditto, Thomas D.; Lysenko, Sergiy; Crenshaw, Melissa



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



Correlation between Local Stress and Strain and Lamina Cribrosa Connective Tissue Volume Fraction in Normal Monkey Eyes  

PubMed Central

Purpose. To investigate the biomechanical response to IOP elevation of normal monkey eyes using eye-specific, three-dimensional (3-D) finite element (FE) models of the ONH that incorporate lamina cribrosa (LC) microarchitectural information. Methods. A serial sectioning and episcopic imaging technique was used to reconstruct the ONH and peripapillary sclera of four pairs of eyes fixed at 10 mm Hg. FE models were generated with local LC material properties representing the connective tissue volume fraction (CTVF) and predominant LC beam orientation and used to simulate an increase in IOP from 10 to 45 mm Hg. An LC material stiffness constant was varied to assess its influence on biomechanical response. Results. Strains and stresses within contralateral eyes were remarkably similar in both magnitude and distribution. Strain correlated inversely, and nonlinearly, with CTVF (median, r 2 = 0.73), with tensile strains largest in the temporal region. Stress correlated linearly with CTVF (median r2 = 0.63), with the central and superior regions bearing the highest stresses. Net average LC displacement was either posterior or anterior, depending on whether the laminar material properties were compliant or stiff. Conclusions. The results show that contralateral eyes exhibit similar mechanical behavior and suggest that local mechanical stress and strain within the LC are correlate highly with local laminar CTVF. These simulations emphasize the importance of developing both high-resolution imaging of the LC microarchitecture and next-generation, deep-scanning OCT techniques to clarify the relationships between IOP-related LC displacement and CTVF-related stress and strain in the LC. Such imaging may predict sites of IOP-related damage in glaucoma.

Roberts, Michael D.; Liang, Yi; Sigal, Ian A.; Grimm, Jonathan; Reynaud, Juan; Bellezza, Anthony; Burgoyne, Claude F.



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.

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



Low-Normal Lung Volume Correlates With Pulmonary Hypertension in Fibrotic Idiopathic Interstitial Pneumonia: Computer-Aided 3D Quantitative Analysis of Chest CT.  


OBJECTIVE. We investigated whether the lung volume determined on CT, especially the volume of the normal lung, is correlated with mean pulmonary artery pressure (PAP) in patients with chronic fibrosing idiopathic interstitial pneumonia (IIP). MATERIALS AND METHODS. The subjects were 40 patients with IIP who underwent right heart catheterization (RHC) and chest CT. Thirty-three patients (82.5%) were smokers or former smokers. Using a computer-aided system, the lungs in the 3D CT images were automatically categorized pixel-by-pixel with gaussian histogramnormalized correlations, and the relative volume of each lesion to the CT lung volume was calculated as "normal(%)," "ground-glass opacities(%)," "consolidation(%)," "emphysema(%)," and "fibrosis(%)." The relationship between each "volume(%)" and pulmonary hypertension was evaluated using logistic regression analysis. ROC curves were constructed to assess the predictive value of these CT-based volumes in the identification of pulmonary hypertension. RESULTS. Sixteen patients had pulmonary hypertension at rest (mean PAP > 25 mm Hg on RHC). Emphysema constituted more than 10% of the CT lung volume in 13 patients. On multivariate analysis of each volume(%), normal(%) was significant for detecting pulmonary hypertension (odds ratio, 0.92; 95% CI, 0.86-0.96; p = 0.02). On ROC analysis, the AUC of normal(%) was 0.849 (0.731-0.967). CONCLUSION. The relative CT volume of any single lesion was of limited value in predicting pulmonary hypertension in patients with pulmonary fibrosis and emphysema. In these patients, normal(%), measured by a 3D computer-aided system, was correlated with pulmonary hypertension measured by RHC. PMID:25055292

Iwasawa, Tae; Kato, Shingo; Ogura, Takashi; Kusakawa, Yuka; Iso, Shinichiro; Baba, Tomohisa; Fukui, Kazuki; Oba, Mari S



Entorhinal cortex volume measured with 3T MRI is positively correlated with the Wechsler Memory Scale-Revised logical\\/verbal memory score for healthy subjects  

Microsoft Academic Search

Introduction  Previous studies revealed a correlation between local brain volume and cognitive function. The aim of the present study was\\u000a to investigate the correlation between local gray matter volume and the Wechsler Memory Scale-Revised (WMS-R) logical\\/verbal\\u000a memory (WMS-R-verbal) score in healthy adults using a 3 Tesla magnetic resonance scanner and voxel-based morphometry (VBM).\\u000a \\u000a \\u000a \\u000a \\u000a Methods  T1-weighted magnetic resonance images were obtained in 1,169

Masami Goto; Osamu Abe; Tosiaki Miyati; Takeharu Yoshikawa; Naoto Hayashi; Hidemasa Takao; Sachiko Inano; Hiroyuki Kabasawa; Harushi Mori; Akira Kunimatsu; Shigeki Aoki; Kenji Ino; Kyouhito Iida; Keiichi Yano; Kuni Ohtomo



Unitarity and the holographic S-Matrix  

NASA Astrophysics Data System (ADS)

The bulk S-Matrix can be given a non-perturbative definition in terms of the flat space limit of AdS/CFT. We show that the unitarity of the S-Matrix, ie the optical theorem, can be derived by studying the behavior of the OPE and the conformal block decomposition in the flat space limit. When applied to perturbation theory in AdS, this gives a holographic derivation of the cutting rules for Feynman diagrams. To demonstrate these facts we introduce some new techniques for the analysis of conformal field theories. Chief among these is a method for conglomerating local primary operators {{{O}}_1} and {{{O}}_2} to extract the contribution of an individual primary {{{O}}_{{\\varDelta, ell }}} in their OPE. This provides a method for isolating the contribution of specific conformal blocks which we use to prove an important relation between certain conformal block coefficients and anomalous dimensions. These techniques make essential use of the simplifications that occur when CFT correlators are expressed in terms of a Mellin amplitude.

Fitzpatrick, A. Liam; Kaplan, Jared



Entanglement in holographic dark energy models  

NASA Astrophysics Data System (ADS)

We study a process of equilibration of holographic dark energy (HDE) with the cosmic horizon around the dark-energy dominated epoch. This process is characterized by a huge amount of information conveyed across the horizon, filling thereby a large gap in entropy between the system on the brink of experiencing a sudden collapse to a black hole and the black hole itself. At the same time, even in the absence of interaction between dark matter and dark energy, such a process marks a strong jump in the entanglement entropy, measuring the quantum-mechanical correlations between the horizon and its interior. Although the effective quantum field theory (QFT) with a peculiar relationship between the UV and IR cutoffs, a framework underlying all HDE models, may formally account for such a huge shift in the number of distinct quantum states, we show that the scope of such a framework becomes tremendously restricted, devoid virtually any application in other cosmological epochs or particle-physics phenomena. The problem of negative entropies for the non-phantom stuff is also discussed.

Horvat, R.



Photoplastic recording materials in holographic memories  

NASA Technical Reports Server (NTRS)

The application of reusable, sensitive, and efficient photoplastic recording materials in read/write holographic memories is reviewed. The composition, preparation, and typical configurations of photoplastics, as well as the techniques for recording and erasing the holographic information, are described. The effects of sample thickness, exposure time, illuminating wavelength, development, and reusability on the holographic signal are examined. Experimental measurements reveal that diffraction efficiencies in excess of 10 percent can be achieved and that the exposure sensitivities and noise characteristics are comparable to high-resolution photographic emulsions. As the number of recording-erasure cycles of photoplastic holograms increases, the signal-to-noise ratio (S/N) of the holographic readout image deteriorates. However, the number of cycles can be over 100 with adequate S/N. Finally, experimental results showing the quality of the reconstructions that can be achieved from a 5 x 5 hologram array are presented.

Friesem, A. A.; Tompkins, E. N.



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)



Interacting holographic generalized Chaplygin gas model  

Microsoft Academic Search

In this Letter we consider a correspondence between the holographic dark energy density and interacting generalized Chaplygin gas energy density in FRW universe. Then we reconstruct the potential of the scalar field which describe the generalized Chaplygin cosmology.

M. R. Setare



Review of Photosensitive Materials for Holographic Recordings.  

National Technical Information Service (NTIS)

There is a program objective to systematically evaluate photosensitive recording materials that can be used in holographic and other coherent optical systems. In association with this, a detailed literature search was undertaken in which considerable info...

J. W. Gladden



Displacement Determination by Digital Holographic Interferometry  

NASA Astrophysics Data System (ADS)

Digital Holographic Interferometry is a useful technique for measuring the deformation or displacement of the surface of an object by recording at least two speckle patterns, one before and one after the object is deformed. Holographic interferometry utilizes interference between the speckled image of an object illuminated by a laser and a reference beam derived from the same laser. Any change in the shape of the object results in local changes in the intensity distribution in the holographic fringe pattern. This optical technique allows detecting deformation with sensitivity smaller than the wavelength of light. The holograms are generated directly on a charge coupled device (CCD) target and stored electronically. The speckle patterns can be taken quickly analyzed using Holographic interferometry and Fourier transform method.

Abdelhakim, Lotfi



The Pioneer anomaly and the holographic scenario  

NASA Astrophysics Data System (ADS)

In this paper we discuss the recently obtained relation between the Verlinde's holographic model and the first phenomenological Modified Newtonian dynamics. This gives also a promising possible explanation to the Pioneer anomaly.

Giné, Jaume



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.



Application of Holographic Stereograms to Photographic Interpretation.  

National Technical Information Service (NTIS)

Techniques were developed for displaying 3-D images of terrain photography, in an attempt to increase the effectiveness of reconnaissance interpretation by trained and untrained personnel. Two holographic stereogram methods were developed. The first metho...

J. T. McCrickerd



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.



Miniaturized optical correlator  

NASA Technical Reports Server (NTRS)

A robust optical correlator that is a miniaturized version of the classic Vander-Lugt correlator is developed. The correlator consists of a simple diode laser for illumination and a CMOS photodetector to detect the correlation peak. A set of roof prisms is configured to fold the light path into a compact design. A holographic plate is used for storing the matched filter. This correlator is particularly applicable to docking autonomous vehicles near a predesignated landing mark. This miniature optical correlator is described in terms of its functional performance.

Scholl, M. S.; Shumate, M. S.; Hartman, R. L.; Sloan, J. A.; Small, D.



Holographic surface gratings in iron-doped lithium niobate  

NASA Astrophysics Data System (ADS)

Surface gratings associated with holographic volume gratings in photorefractive crystals of iron-doped lithium niobate have been studied using diffraction of a reflected probe beam and high-resolution phase-shifted interferometric profilometry. Both techniques show that the surface gratings exist in the form of periodical corrugations of the same period as that of the volume grating. The maximum amplitude of the periodical surface relief measured by both techniques is close to 6.5 nm. We also demonstrated that the periodical electric forces on the surface were capable of assembling polystyrene microspheres along the fringes of the grating. Large amplitude of the periodic electric field (1.6×104 V/cm) is associated with the photogalvanic effect.

Sarkisov, S. S.; Curley, M. J.; Kukhtarev, N. V.; Fields, A.; Adamovsky, G.; Smith, C. C.; Moore, L. E.



The recent holographic material: Konica P7000  

NASA Astrophysics Data System (ADS)

A newly developed silver halide material, KONIKA MINOLTA OPTO P7000, was examined its holographic characteristics. The commercially available material, KONIKA P5600, is blue-green sensitive but the new P7000 shows enough sensitivity to red light for practical use. We recorded holograms with He-Ne laser light on P7000 plates and evaluated the holographic characteristics such as diffraction efficiency and reconstructed wavelength. The results are discussed comparing with those of former Agfa products.

Iwasaki, Masashi; Kubota, Toshihiro; Watanabe, Masachika; Yamauchi, Tsuyoshi; Kumasawa, Tomoko; Ueda, Kenji



Holographic Optical Elements as Scanning Lidar Telescopes  

NASA Technical Reports Server (NTRS)

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

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



Interacting Ricci-like holographic dark energy  

NASA Astrophysics Data System (ADS)

In a flat Friedmann-Lemaitre-Robertson-Walker background, a scheme of dark matter-dark energy interaction is studied considering a holographic Ricci-like model for the dark energy. Without giving a priori some specific model for the interaction function, we show that this function can experience a change of sign during the cosmic evolution. The parameters involved in the holographic model are adjusted with Supernova data and we obtained results compatible with the observable universe.

Arévalo, F.; Cifuentes, P.; Lepe, Samuel; Peña, Francisco



Bose-Fermi competition in holographic metals  

NASA Astrophysics Data System (ADS)

We study the holographic dual of a finite density system with both bosonic and fermionic degrees of freedom. There is no evidence for a universal bose-dominated ground state. Instead, depending on the relative conformal weights the preferred groundstate is either pure AdS-Reissner-Nordstrom, a holographic superconductor, an electron star, or a novel mixed state that is best characterized as a hairy electron star.

Liu, Yan; Schalm, Koenraad; Sun, Ya-Wen; Zaanen, Jan



Stratified volume diffractive optical elements  

Microsoft Academic Search

Gratings with high diffraction efficiency into a single order find use in applications ranging from optical interconnects to beam steering. Such gratings have been realized with volume holographic, blazed, and diffractive optical techniques. However, each of these methods has limitations that restrict the range of applications in which they can be used. In this work an alternate, novel approach and

Diana Marie Chambers



Correlation between surrogates of bladder dosimetry and dose-volume histograms of the bladder wall defined on MRI in prostate cancer radiotherapy.  


The correlation between bladder dose-wall-histogram (DWH) and dose-volume-histogram (DVH), dose-surface-histogram (DSH), and DVH-5/10 was investigated in a group of 28 patients; bladder walls were drawn on T2-MRI. DVH showed the poorest correlation with DWH; DSH or DVH-5/10 should be preferred in planning; absolute DVH may be used for radical patients, although less robust. PMID:23182056

Carillo, Viviana; Cozzarini, Cesare; Chietera, Andreina; Perna, Lucia; Gianolini, Stefano; Maggio, Angelo; Botti, Andrea; Rancati, Tiziana; Valdagni, Riccardo; Fiorino, Claudio



Influence of TFT-LCD pixel structure on holographic representation  

NASA Astrophysics Data System (ADS)

As a new holographic display device, TFT-LCD (Thin Film Transistor Liquid Crystal Displays) is key technical component of holographic representation for easy controlled by computer. With the development of exquisite processing technology, that it instead of the traditional holographic plate become historical necessity and would be the development direction of holographic optics. Based on principles of holography and display character of LCD, the property which the LCD was used as a holographic plate was analyzed. The emphasis on discuss influence of LCD black matrix on holographic representation. First, analyzed on LCD pixel structure, the LCD pixel structure mathematical model was established. LCD was character representation by pixel structure parameters. Then, the influence of LCD pixels structure on holographic representation was analyzed by computer simulation. Meanwhile, the SONY LCX023 was chosen for holographic plate, the He-Ne laser which the wavelength is 0.6328um was holographic representation light source. The holographic representation system was established for test influence of LCD on holographic representation. Final, compared between computer simulations and optical experimental results, the mathematical model of LCD was proved to be true. When aperture ratio is 0.625, the holographic representation wouldn't be distinguished between representation images. At the same time, some useful results was acquired for improve application effects of LCD in holographic representation.

Wang, Hongjun; Wang, Zhao; Tian, Ailing; Liu, Bingcai



Pulsed lasers for holographic interferometry  

NASA Astrophysics Data System (ADS)

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

Pitlak, R. T.; Page, R.



Holographic Thermalization at Intermediate Coupling  

NASA Astrophysics Data System (ADS)

We use the AdS/CFT conjecture to investigate the thermalization of large-Nc N=4 super Yang-Mills plasma in the limit of large but finite ’t Hooft coupling. On the gravity side, we supplement the type IIB supergravity action by the full set of O(?'3) operators, which enables us to derive O(?-3/2) corrections to the emission spectrum of prompt photons in one model of holographic thermalization. Decreasing the coupling strength from the ?=? limit, we observe a qualitative change in the way the photon spectral density approaches its thermal limit as a function of the photon energy. We interpret this behavior as a sign of the thermalization pattern of the plasma shifting from top-down towards bottom-up.

Steineder, Dominik; Stricker, Stefan A.; Vuorinen, Aleksi



Incoherent digital holographic adaptive optics.  


An adaptive optical system based on incoherent digital holography is described. Theoretical and experimental studies show that wavefront sensing and compensation can be achieved by numerical processing of digital holograms of incoherent objects and a guide star, thereby dispensing with the hardware components of conventional adaptive optics systems, such as lenslet arrays and deformable mirrors. The incoherent digital holographic adaptive optics (IDHAO) process is seen to be robust and effective under various ranges of parameters, such as aberration type and strength. Furthermore, low and noisy image signals can be extracted by IDHAO to yield high-quality images with good contrast and resolution, both for point-like and continuous extended objects, illuminated with common incoherent light. Potential applications in astronomical and other imaging systems appear plausible. PMID:23292384

Kim, Myung K



Correlations between relative interstitial volume of the renal cortex and serum creatinine concentration in minimal changes with nephrotic syndrome and in focal sclerosing glomerulonephritis  

Microsoft Academic Search

Morphometric investigations were performed in 33 biopsies with minimal proliferative intercapillary glomerulonephritis with nephrotic syndrome (MPI with NS, minimal changes with nephrotic syndrome) and in 65 biopsies with focal sclerosing glomerulonephritis (FGS). Both diseases are, in our opinion, variants of a single entity. Positive significant correlations (corresponding to linear and parabolic functions) between the relative interstitial volume of the renal

A. Bohle; D. Glomb; K. E. Grund; S. Mackensen



Position, scale, and rotation invariant holographic associative memory  

SciTech Connect

An all-optical holographic memory was recently proposed. This paper details the investigation into the characteristics of that system and an extension to a position, scale, and rotation invariant (PSR) holographic associative memory. The PSRI feature space is the {ell}n-polar representation of the square magnitude of the Fourier transform, {vert bar}F(f{sub {ital l}nr}, f{sub {theta}}){vert bar}{sup 2}, of the objects. This representation is generated optically using a coordinate transform computer-generated hologram. Angularly multiplexed, diffuse Fourier transform holograms of the PSRI feature space are characterized as the memory unit. Distorted input objects are correlated with the hologram, and a nonlinear phase conjugate mirror, self-pumped BaTiO{sub 3}, reduces cross-correlation noise and provides object discrimination. The self-pumped phase conjugate mirror is characterized, and high diffraction efficiency bleached holograms are used in the place of thermoplastic film. Applications of the memory are also presented.

Fielding, K.H.; Rogers, S.K.; Kabrisky, M.; Mills, J.P. (Air Force Institute of Technology, Wright Patterson AFB, OH (US))



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



Measurement of Surface Contours Using Holographically Stored Interference Fields.  

National Technical Information Service (NTIS)

A holographic technique which does not require the stable and vibration free experimental set-up of normal holographic arrangements is described for generating surface contours. Contour lines are formed on the object to be measured by the intersection of ...

H. Wachutka W. M. Ewers K. Barwinkle



Digital holographic microscopy for live cell applications and technical inspection.  


Digital holographic microscopy enables a quantitative phase contrast metrology that is suitable for the investigation of reflective surfaces as well as for the marker-free analysis of living cells. The digital holographic feature of (subsequent) numerical focus adjustment makes possible applications for multifocus imaging. An overview of digital holographic microscopy methods is described. Applications of digital holographic microscopy are demonstrated by results obtained from livings cells and engineered surfaces. PMID:18239699

Kemper, Björn; von Bally, Gert



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.

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



Comparing holographic dark energy models with statefinder  

NASA Astrophysics Data System (ADS)

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 CDM model in the and evolutions. In particular, the HDE model is highly degenerate with the 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 and diagnostics by using some quantities with higher order derivatives of the scale factor. It is shown that the statefinder diagnostic 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 CDM model can also be broken by this method. Especially for the HDE model, all the previous strong degeneracies appearing in the and 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 - plane is also made, in which the separations between the models (including the CDM model) can be directly measured in the light of the current values of the models.

Cui, Jing-Lei; Zhang, Jing-Fei



Holographic data storage: rebirthing a commercialization effort  

NASA Astrophysics Data System (ADS)

The realization of a commercial holographic data storage device has remained elusive for many decades. The most recent efforts were by InPhase Technologies between 2001 and 2009 resulting in 52 functioning prototypes capable of 300GB/disk and 20MB/s transfer rates. Despite being the world's first fully functional holographic drives, the primary competitor to holographic archive storage at that time, LTO, had already achieved 800GB and 120MB/in 2008; and by 2010, LTO had achieved 1.5TB and 140MB/s. This left InPhase at a competitive disadvantage to LTO archive solutions despite other strengths such as robustness, random access, and longer-term archive lifetime. Looking into the future, holographic data storage must be highly competitive with tape in three critical areas: cost/TB, capacity/footprint, and transfer rate. If this can be achieved, holographic data storage would become a superior solution given the low latencies and overall robustness to propel it into being the archive storage front-runner. New technology advancements by Akonia Holographics have enabled the potential for ultra-high capacity holographic storage devices that are capable of world record bit densities of over 2Tbit/in2, 200-300MB/s transfer rates, and a media cost less than $10/TB in the next 5 years. A demonstration platform based on these new advances has been designed and is currently being built by Akonia to progressively demonstrate bit densities of 2Tb/in2, 4Tb/in2, and 8Tb/in2 over the next year.

Anderson, Ken; Ayres, Mark; Sissom, Brad; Askham, Fred



The holographic dual of AdS 3 × S3 × S3 × S1  

NASA Astrophysics Data System (ADS)

We construct the two dimensional = (0, 4) gauge theory that lives on the world volume of D1-branes and intersecting D5-branes. We conjecture that this theory flows in the infra-red to a fixed point with large = (4, 4) superconformal symmetry. The central charge of the conformal field theory is shown to coincide with the holographic dual of string theory compactified on AdS 3 × S 3 × S 3 × S 1.

Tong, David



Photosensitive monomer and oligomer materials for holographic recording in the visible and near IR  

NASA Astrophysics Data System (ADS)

Recording media based on the polymerization of monomers and oligomers commonly used in the Radiation Curing area, appear to be promising materials to record holographic patterns produced by laser sources emitting in the visible and near infrared part of the spectrum. A polymerization takes place only in the bright areas of the interference pattern and volume phase holograms exhibiting high diffraction efficiencies which can be viewed immediately after exposure, are created. Several examples of monophotonic and biphotonic systems will be discussed and presented.

Fouassier, Jean-Pierre; Morlet-Savary, Christiane C.; Lougnot, Daniel-Joseph



SVZ?1/q2-expansion versus some QCD holographic models  

NASA Astrophysics Data System (ADS)

Considering the classical two-point correlators built from (axial-) vector, scalar qbarq and gluonium currents, we confront results obtained using the SVZ?1/q2-expansion to the ones from some QCD holographic models in the Euclidean region and with negative dilaton ?i(z)=-|ci2|z2. We conclude that the presence of the 1/q2-term in the SVZ-expansion due to a tachyonic gluon mass appears naturally in the Minimum Soft-Wall (MSW) and the Gauge/String Dual (GSD) models which can also reproduce semi-quantitatively some of the higher dimension condensate contributions appearing in the OPE. The Hard-Wall model shows a large departure from the SVZ?1/q2-expansion in the vector, scalar and gluonium channels due to the absence of any power corrections. The equivalence of the MSW and GSD models is manifest in the vector channel through the relation of the dilaton parameter with the tachyonic gluon mass. For approximately reproducing the phenomenological values of the dimension d=4,6 condensates, the holographic models require a tachyonic gluon mass (?s/?)?2?-(0.12-0.14) GeV, which is about twice the fitted phenomenological value from e+e- data. The relation of the inverse length parameter ci to the tachyonic gluon mass also shows that ci is channel dependent but not universal for a given holographic model. Using the MSW model and M?=0.78 GeV as input, we predict a scalar qbarq mass MS?(0.95-1.10) GeV and a scalar gluonium mass MG?(1.1-1.3) GeV.

Jugeau, F.; Narison, S.; Ratsimbarison, H.



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



NT-pro-BNP levels in patients with acute pulmonary embolism are correlated to right but not left ventricular volume and function.  


N-terminal pro-Brain Natriuretic Peptide (NT-pro-BNP) is primarily secreted by left ventricular (LV) stretch and wall tension. Notably, NT-pro-BNP is a prognostic marker in acute pulmonary embolism (PE), which primarily stresses the right ventricle (RV). We sought to evaluate the relative contribution of the RV to NT-pro-BNP levels during PE. A post-hoc analysis of an observational prospective outcome study in 113 consecutive patients with computed tomography (CT)-proven PE and 226 patients in whom PE was clinically suspected but ruled out by CT. In all patients RV and LV function was established by assessing ECG-triggered-CT measured ventricular end-diastolic-volumes and ejection fraction (EF). NT-pro-BNP was assessed in all patients. The correlation between RV and LV end-diastolic-volumes and systolic function was evaluated by multiple linear regression corrected for known confounders. In the PE cohort increased RVEF (?-coefficient (95% confidence interval [CI]) -0.044 (± -0.011); p<0.001) and higher RV end-diastolic-volume (?-coefficient 0.005 (± 0.001); p<0.001) were significantly correlated to NT-pro-BNP, while no correlation was found with LVEF (?-coefficient 0.005 (± 0.010); p=0.587) and LV end-diastolic-volume (?-coefficient -0.003 (± 0.002); p=0.074). In control patients without PE we found a strong correlation between NT-pro-BNP levels and LVEF (?-coefficient -0.027 (± -0.006); p<0.001) although not LV end-diastolic-volume (?-coefficient 0.001 (± 0.001); p=0.418). RVEF (?-coefficient -0.002 (± -0.006); p=0.802) and RV end-diastolic-volume (?-coefficient <0.001 (± 0.001); p=0.730) were not correlated in patients without PE. In PE patients, lower RVEF and higher RV end-diastolic-volume were significantly correlated to NT-pro-BNP levels as compared to control patients without PE. These observations provide pathophysiological ground for the well-known prognostic value of NT-pro-BNP in acute PE. PMID:22740123

Pasha, Sharif M; Klok, Frederikus A; van der Bijl, Noortje; de Roos, Albert; Kroft, Lucia J M; Huisman, Menno V



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


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

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



d-wave holographic superconductor vortex lattice and non-Abelian holographic superconductor droplet  

NASA Astrophysics Data System (ADS)

A d-wave holographic superconductor in the presence of a constant magnetic field is studied by the perturbation method. We obtain both droplet and triangular vortex lattice solutions. The results are the same as that of an s-wave holographic superconductor. The non-Abelian holographic superconductor with p+ip-wave background in the presence of a magnetic field is also studied. Unlike the d-wave and s-wave models, it is found that the non-Abelian model has only a droplet solution.

Zeng, Hua-Bi; Fan, Zhe-Yong; Zong, Hong-Shi



Autofocusing in digital holographic microscopy  

NASA Astrophysics Data System (ADS)

Many applications in non-destructive testing at a microscopic level and in live cell imaging require automated focusing due to unstable environmental conditions, moving specimen or the limited depth of field of the applied optical imaging systems. Digital holography permits the recording and the numerical reconstruction of optical wave fields in amplitude and phase. This enables imaging of multiple focal planes from a single recorded hologram without mechanical realignment. The combination of numerical refocusing with image sharpness quantification algorithms yields subsequent autofocusing. With calibrated optical imaging systems this feature can be used also to determine the position and axial displacements of a sample. In order to show the application potential of digital holographic autofocusing in microscopy the method and results from investigations on several amplitude and phase objects are reviewed. This includes a demonstration of the reliability of automated refocusing, multi-focus quantitative phase contrast imaging of suspended cells, refocusing of quantitative phase contrast images during the analysis of the temporal dependency of cell spreading on surfaces and the quantification of toxin mediated morphological cell alterations during long-term observations. It is also shown for the example of sedimenting red blood cells that the method can be applied for minimally-invasive tracking of multiple particles. Finally, the usage of numerical autofocus for quantitative migration analysis of arbitrary shaped cells in a three-dimensional collagen matrix is demonstrated. [Figure not available: see fulltext.

Langehanenberg, Patrik; von Bally, Gert; Kemper, Björn



Holographic Adaptive Laser Optics System  

NASA Astrophysics Data System (ADS)

We have created a new adaptive optics system using a holographic modal wavefront sensing method with the autonomous (computer-free) closed-loop control of a MEMS deformable mirror (DM). A multiplexed hologram is recorded using the maximum and minimum actuator positions on the deformable mirror as the “modes”. On reconstruction, an input beam is diffracted into pairs of focal spots and the ratio of the intensities of certain pairs determines the absolute wavefront phase at a particular actuator location. The wavefront measurement is made using fast, sensitive silicon photomultiplier arrays with the parallel outputs directly controlling individual actuators in the MEMS DM. 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 speed is limited only by the response time of any given DM actuator and not the number of actuators. In our case, our 32-actuator prototype device already operates at 10 kHz and our next generation system is being designed for > 100 kHz. As a modal system, it is largely insensitive to scintillation and obscuration and is thus ideal for extreme adaptive optics applications. We will present information on how HALOS can be used for image correction and beam propagation as well as several other novel applications.

Andersen, G.; Ghebremichael, F.



Holographic dark energy in the DGP model  

NASA Astrophysics Data System (ADS)

The braneworld model proposed by Dvali, Gabadadze, and Porrati leads to an accelerated universe without cosmological constant or any other form of dark energy. Nevertheless, we have investigated the consequences of this model when an holographic dark energy is included, taking the Hubble scale as IR cutoff. We have found that the holographic dark energy leads to an accelerated flat universe (de Sitter-like expansion) for the two branches: ?=±1, of the DGP model. Nevertheless, in universes with no null curvature the dark energy presents an EoS corresponding to a phantom fluid during the present era and evolving to a de Sitter-like phase for future cosmic time. In the special case in which the holographic parameter c is equal to one we have found a sudden singularity in closed universes. In this case the expansion is decelerating.

Cruz, Norman; Lepe, Samuel; Peña, Francisco; Avelino, Arturo



Large-distance properties of holographic baryons  

NASA Astrophysics Data System (ADS)

Employing the asymptotic instanton solution in an arbitrary background of a set of holographic QCD models, we show that baryon form factors have a precise large-distance behavior regardless of the background. The dependence coincides with that obtained from general chiral soliton models and large-NC chiral perturbation theory. The nonlinear terms in the equations of motion are necessary to recover the correct results. We also show that the holographic currents have the right structure at low energy if the solutions of the full equation of motion, instead of the linearized ones, are used. The indication is that in this holographic approach, the linearized approximation used in the meson sector is not appropriate for the solitonic description of the baryons.

Colangelo, Pietro; Sanz-Cillero, Juan Jose; Zuo, Fen



Third-generation Rowland holographic mounting.  


Holographic gratings using aspheric blanks and/or aberrated laser recording sources are most often required to achieve high spectral resolution over a large spectral range. We propose a configuration derived from the optimized holographic Rowland mounting, where the grating is recorded by the interference of two aberrated wave fronts diffracted from concave holographic gratings. These two auxiliary gratings are recorded with laser point sources, and the three blanks are spherical, which is well suited to the severe far-UV constraints on shape and polishing. In addition to the correction of astigmatism, coma C(1), and spherical aberration S(1) given by the optimized Rowland mounting, this mounting cancels, at least at one point of the spectrum, coma C(2) and spherical aberrations S(2) and S(3). PMID:20706498

Duban, M



High speed holographic cine-recorder  

NASA Astrophysics Data System (ADS)

Air Force Research Laboratory and North Dancer Labs researchers have completed the initial development and transition to operational use of a high-speed holographic movie system. This paper documents the first fully operational use of a novel and unique experimental capability for high-speed holographic movies and high-speed cinema interferometry. In this paper we document the initial experiments that were performed with the High Speed Holographic Recorder (HSHR) at the Munitions Directorate, Air Force Research Laboratory Site at Eglin, AFB, Florida. These experiments were performed to assess the possibilities for high-speed cine-laser holography combined with high-speed videography to document the formation and propagation of plumes of materials created by impact of high-speed projectiles. This paper details the development of the experimental procedures and initial results of this new tool. After successful integration and testing the system was delivered to Arnold Engineering Development Center.

Snyder, Donald; Watts, David; Gordon, Joseph; Lysogorski, Charles; Powers, Aaron; Perry, John; Chenette, Eugene; Hudson, Roger; Young, Raymond



Holographic wavefront sensor: fast sensing, no computing  

NASA Astrophysics Data System (ADS)

We present results of a fast holographic wavefront sensor. The modal device consists of a multiplexed hologram designed to diffract a single input beam into multiple output beams depending on the amplitude of particular Zernike terms. The aberration and amplitude are determined by the spatial location and intensity of the reconstructed focused spots. The sensing does not require any calculations, so the device is simple, compact and fast. In fact, using several position sensing detectors (PSD), a full description of the wave aberration can be obtained at rates in excess of 100 kHz. The holographic wavefront sensor can be reconfigured for any type of basis set, and is easily adaptable to laser mode profiling. In this talk we will present results of the both the theory and operation of our holographic wavefront sensor.

Andersen, Geoff; Ghebremichael, Fassil; Gurley, Ken



Relapse after radical prostatectomy correlates with preoperative PSA velocity and tumor volume: Results from a screening population  

Microsoft Academic Search

ObjectivesTo evaluate, in a screening population, the impact of tumor volume and prostate volume on prostate-specific antigen (PSA) velocity (PSAV) and to find predictors of biochemical failure after radical prostatectomy. Longitudinal PSA changes in men with prostate cancer have been reported to be significantly different from those without prostate cancer.

Andreas P. Berger; Martina Deibl; Alexander Strasak; Jasmin Bektic; Alexandre Pelzer; Hannes Steiner; Robert Spranger; Gernot Fritsche; Georg Bartsch; Wolfgang Horninger



Holographic memory module with ultra-high capacity and throughput  

SciTech Connect

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

Vladimir A. Markov, Ph.D.



Microspectrometer based on holographically recorded diffractive elements using supplementary holograms.  


The conception and realization of an imaging microspectrometer, limited to an optical volume of 11 x 6 x 5 mm(3), is presented. The spectrometer is based on a multi-order concept and offers an overall spectral bandwidth of 400-1030 nm with better than 2.5 nm resolution in the visible range. The numerical aperture of NA = 0.2 allows an appropriate energy efficiency. As the most essential element of the microspectrometer, a concave diffraction grating with a diameter of 5 mm and an image distance of f = 8.6 mm was manufactured in a holographic recording process. For the recording process the specifications of the concave grating require two diffraction limited point sources in very close proximity. To provide a point source distance below 1 mm a recording concept based on the introduction of a supplementary hologram was employed. PMID:18679501

Brunner, Robert; Burkhardt, Matthias; Rudolf, Klaus; Correns, Nico



Simulating the energy performance of holographic glazings  

NASA Astrophysics Data System (ADS)

The light diffraction properties of holographic diffractive structures present an opportunity to improve the daylight performance in side-lit office spaces by redirecting and reflecting sunlight off the ceiling, providing adequate daylight illumination up to 30 ft (9.14 m) from the window wall. Prior studies of prototypical holographic glazings, installed above conventional `view' windows, have shown increased daylight levels over a deeper perimeter area than clear glass, for selected sun positions. In this study, we report on the simulation of the energy performance of prototypical holographic glazings assuming a commercial office building in the inland Los Angeles climate. The simulation of the energy performance involved determination of both luminous and thermal performance. Since the optical complexity of holographic glazings prevented the use of conventional algorithms for the simulation of their luminous performance, we used a newly developed method that combines experimentally determined directional workplane illuminance coefficients with computer-based analytical routines to determine a comprehensive set of daylight factors for many sun positions. These daylight factors were then used within the DOE-2.1D energy simulation program to determine hourly daylight and energy performance over the course of an entire year for four window orientations. Since the prototypical holographic diffractive structures considered in this study were applied on single pane clear glass, we also simulated the performance of hypothetical glazings, assuming the daylight performance of the prototype holographic glazings and the thermal performance of double-pane and low-e glazings. Finally, we addressed various design and implementation issues towards potential performance improvement.

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



Three-dimensional TV using holographic stereogram  

NASA Astrophysics Data System (ADS)

Computer holographic stereogram (CHS) is useful for holographic 3D TV because it is constructed from the multi horizontal viewpoint plane images and is compatible to the multi camera stereoscopic 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 size and the resolution points of LCD. Therefore we used two LCDs for CHS and arranged them horizontally and increased the viewing points to two times and considered how viewing area and reconstructed images of CHS were improved.

Sato, Koki; Koizumi, Shinya; Chou, Koumei; Takano, Kunihiko



Shape of mesons in holographic QCD  

SciTech Connect

Based on the expectation that the constituent quark model may capture the right physics in the large N limit, we point out that the orbital angular momentum of the quark-antiquark pair inside light mesons of low spins in the constituent quark model may provide a clue for the holographic dual string model of large N QCD. Our discussion, relying on a few suggestive assumptions, leads to a necessity of world-sheet fermions in the bulk of dual strings that can incorporate intrinsic spins of fundamental QCD degrees of freedom. We also comment on the interesting issue of the size of mesons in holographic QCD.

Torabian, Mahdi; Yee, Ho-Ung [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34014, Trieste (Italy)



DBI equations and holographic dc conductivity  

NASA Astrophysics Data System (ADS)

We provide a simple method for writing the Dirac-Born-Infeld equations of a Dp-brane in an arbitrary static background whose metric depends only on the holographic radial coordinate z. Using this method we revisit the Karch-O’Bannon procedure to calculate the dc conductivity in the presence of constant electric and magnetic fields for backgrounds where the boundary is four- or three-dimensional and satisfies homogeneity and isotropy. We find a frame-independent expression for the dc conductivity tensor. For particular backgrounds we recover previous results on holographic metals and strange metals.

Ballon-Bayona, Alfonso; N. Ferreira, Cristine; Vasquez Otoya, Victor J.



Holographic diversity interferometry for optical storage.  


This study proposes holographic diversity interferometry (HDI), a system that combines information from spatially dispersed plural image sensors to reconstruct complex amplitude distributions of light signals. HDI can be used to generate four holographic interference fringes having different phases, thus enabling optical phase detection in a single measurement. Unlike conventional phase-shifting digital holography, this system does not require piezoelectric elements and phase shift arrays. In order to confirm the effectiveness of HDI, we generated optical signals having multilevel phases and amplitudes by using two SLMs and performed an experiment for detection and demodulation with HDI. PMID:21747499

Okamoto, Atsushi; Kunori, Keisuke; Takabayashi, Masanori; Tomita, Akihisa; Sato, Kunihiro



Holographic cold nuclear matter and neutron star  

NASA Astrophysics Data System (ADS)

We have previously found a new phase of cold nuclear matter based on a holographic gauge theory, where baryons are introduced as instanton gas in the probe D8//lineD8 branes. In our model, we could obtain the equation of state (EOS) of our nuclear matter by introducing Fermi momentum. Then, here we apply this model to the neutron star and study its mass and radius by solving the Tolman-Oppenheimer-Volkoff (TOV) equations in terms of the EOS given here. We give some comments for our holographic model from a viewpoint of the other field theoretical approaches.

Ghoroku, Kazuo; Kubo, Kouki; Tachibana, Motoi; Toyoda, Fumihiko



Real-time wideband holographic surveillance system  


A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm.

Sheen, David M. (1917 Hood, Richland, WA 99352); Collins, H. Dale (1751 Duluth, Richland, WA 99352); Hall, Thomas E. (8301 W. Entiat Pl., Kennewick, WA 99336); McMakin, Douglas L. (2173 Shasta Ave., Richland, WA 99352); Gribble, R. Parks (1215 Cottonwood Dr., Richland, WA 99352); Severtsen, Ronald H. (1803 Birch Ave., Richland, WA 99352); Prince, James M. (3029 W. 2nd Ave., Apt. F95, Kennewick, WA 99336); Reid, Larry D. (Rt. 1, Box 1291B, Benton City, WA 99320)



Holographic currents and Chern-Simons terms  

SciTech Connect

Holographic currents and their associated Ward identities are derived in the framework of gravity/gauge duality. Holographic improvements of the energy-momentum tensor and R-symmetry current which are consistent with the Ward identities are displayed. The effects of specific string loop corrections to the bulk action are included as four derivative effective Lagrangian terms and their contributions to the trace and R-symmetry anomalies of the boundary theory are determined. As an example, the construction is applied to the N=2 conformal supergravity which is taken to be dual to a boundary SU(N)xSU(N), N=1 superconformal field theory.

Clark, T. E.; Love, S. T.; Veldhuis, T. ter [Department of Physics, Purdue University, West Lafayette, Indiana 47907-2036 (United States); Department of Physics and Astronomy, Macalester College, Saint Paul, Minnesota 55105-1899 (United States)



Real-time wideband holographic surveillance system  


A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm. 28 figs.

Sheen, D.M.; Collins, H.D.; Hall, T.E.; McMakin, D.L.; Gribble, R.P.; Severtsen, R.H.; Prince, J.M.; Reid, L.D.



Real-time holographic surveillance system  


A holographic surveillance system including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm.

Collins, H. Dale (Richland, WA); McMakin, Douglas L. (Richland, WA); Hall, Thomas E. (Kennewick, WA); Gribble, R. Parks (Richland, WA)



Real-time holographic surveillance system  


A holographic surveillance system is disclosed including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm. 21 figs.

Collins, H.D.; McMakin, D.L.; Hall, T.E.; Gribble, R.P.



Holographic interferometry: A user`s guide  

SciTech Connect

This manual describes the procedures and components necessary to produce a holographic interferogram of a flow field in the Sandia National Laboratories hypersonic wind tunnel. In contrast to classical interferometry, holographic interferometry records the amplitude and phase distribution of a lightwave passing through the flow field at some instant of time. This information can then be reconstructed outside the wind tunnel for visual analysis and digital processing, yielding precise characterizations of aerodynamic phenomena. The reconstruction and subsequent hologram image storage process is discussed, with particular attention paid to the digital image processor and the data reduction technique.

Griggs, D.



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

NASA Astrophysics Data System (ADS)

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

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



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.  


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



Applicability of cubic equation of state mixing rules on correlation of excess molar volume of non-electrolyte binary mixtures – Part II  

Microsoft Academic Search

The excess molar volume (V?) data of the 24 binary highly non-ideal mixtures containing dicyclic ethers (593 data points) were correlated by the Peng–Robinson–Stryjek–Vera (PRSV) cubic equation of state (CEOS) coupled with two different classes of mixing rules: (i) the composition dependent van der Waals (vdW) mixing rule and (ii) the excess free energy mixing rules (CEOS\\/G?) based on the

Mirjana L. J. Kijev?anin; Bojan D. Djordjevi?; Slobodan P. Šerbanovi?; Ivona R. Radovi?; Aleksandar Ž. Tasi?



Six-Minute Walking Distance Correlated with Memory and Brain Volume in Older Adults with Mild Cognitive Impairment: A Voxel-Based Morphometry Study  

PubMed Central

Background/Aims High fitness levels play an important role in maintaining memory function and delaying the progression of structural brain changes in older people at risk of developing dementia. However, it is unclear which specific regions of the brain volume are associated with exercise capacity. We investigated whether exercise capacity, determined by a 6-min walking distance (6MWD), is associated with measures of logical and visual memory and where gray matter regions correlate with exercise capacity in older adults with mild cognitive impairment (MCI). Methods Ninety-one community-dwelling older adults with MCI completed a 6-min walking test, structural magnetic resonance imaging scanning, and memory tests. The Wechsler Memory Scale-Revised Logical Memory and Rey-Osterrieth Complex Figure Tests were used to assess logical and visual memory, respectively. Results The logical and visual memory tests were positively correlated with the 6MWD (p < 0.01). Poor performance in the 6MWD was correlated with a reduced cerebral gray matter volume in the left middle temporal gyrus, middle occipital gyrus, and hippocampus in older adults with MCI. Conclusions These results suggest that a better 6MWD performance may be related to better memory function and the maintenance of gray matter volume in older adults with MCI.

Makizako, Hyuma; Shimada, Hiroyuki; Doi, Takehiko; Park, Hyuntae; Yoshida, Daisuke; Suzuki, Takao



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

PubMed Central

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

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