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1

Bunch Length Measurements With Laser/SR Cross-Correlation  

SciTech Connect

By operating SPEAR3 in low-{alpha} mode the storage ring can generate synchrotron radiation pulses of order 1ps. Applications include pump-probe x-ray science and the production of THz radiation in the CSR regime. Measurements of the bunch length are difficult, however, because the light intensity is low and streak cameras typically provide resolution of only a few ps. Tests are now underway to resolve the short bunch length using cross-correlation between a 60-fs Ti:Sapphire laser and the visible SR beam in a BBO crystal. In this paper we report on the experimental setup, preliminary measurements and prospects for further improvement.

Miller, Timothy; /Stanford U., Phys. Dept.; Daranciang, Dan; /Stanford U., Phys. Dept.; Lindenberg, Aaron; /Stanford U., Phys. Dept.; Corbett, Jeff; /SLAC; Fisher, Alan; /SLAC; Goodfellow, John; /SLAC; Huang, Xiaobiao; /SLAC; Mok, Walter; /SLAC; Safranek, James; /SLAC; Wen, Haidan; /SLAC

2012-07-06

2

Turbulence Radial Correlation Length Measurements in the Core of NSTX  

NASA Astrophysics Data System (ADS)

Assessment of ion thermal transport via TRANSP as well as linear gyrokinetic stability analyses have suggested that long-wavelength (k_??_i? 1) ITG-like turbulence may be strongly suppressed in the ST. The first direct measurements of long-wavelength turbulence in the core of NSTX have been made using homodyne radial correlation reflectometry. The system has a frequency coverage of 26-40 GHz (0.84 to 2.0×10^13 cm-3 in O-mode) and has been used to measure turbulence radial correlation lengths in the core (r/a ˜0.2-0.8) of low beam power, L-mode discharges. Scans were performed to observe the scaling of the turbulence and confinement properties: Bt and Ip were varied simultaneously (constant q, ? scan) and independently. Initial analyses indicate correlation lengths in the range of 5-15 cm and decreasing with increasing local magnetic field strength. Comparisons will be made with nonlinear gyrokinetic simulations using the GYRO code.

Kubota, S.; Peebles, W. A.; Crocker, N. A.; Nguyen, X. V.; Mikkelsen, D. R.; Bell, R. E.; Kaye, S. M.; Leblanc, B. P.; Roquemore, A. L.; Candy, J.; Waltz, R. E.; Gilmore, M.

2004-11-01

3

Correlation length by measuring empty space in simulated aggregates  

NASA Astrophysics Data System (ADS)

We examine the geometry of the spaces between particles in diffusion-limited cluster aggregation, a numerical model of aggregating suspensions. Computing the distribution of distances from each point to the nearest particle, we show that it has a scaled form independent of the concentration phi, for both two- (2D) and three-dimensional (3D) model gels at low phi. The mean remoteness is proportional to the density-density correlation length of the gel, ?, allowing a more precise measurement of ? than by other methods. A simple analytical form for the scaled remoteness distribution is developed, highlighting the geometrical information content of the data. We show that the second moment of the distribution gives a useful estimate of the permeability of porous media.

Evans, R. M. L.; Haw, M. D.

2002-11-01

4

Measuring the correlation length of intergalactic magnetic fields from observations of gamma-ray induced cascades  

NASA Astrophysics Data System (ADS)

Context. The imaging and timing properties of ?-ray emission from electromagnetic cascades initiated by very-high-energy (VHE) ?-rays in the intergalactic medium depend on the strength B and correlation length ?B of intergalactic magnetic fields (IGMF). Aims: We study the possibility of measuring both B and ?B via observations of the cascade emission with ?-ray telescopes. Methods: For each measurement method, we find two characteristics of the cascade signal, which are sensitive to the IGMF B and ?B values in different combinations. For the case of IGMF measurement using the observation of extended emission around extragalactic VHE ?-ray sources, the two characteristics are the slope of the surface brightness profile and the overall size of the cascade source. For the case of IGMF measurement from the time delayed emission, these two characteristics are the initial slope of the cascade emission light curve and the overall duration of the cascade signal. Results: We show that measurement of the slope of the cascade induced extended emission and/or light curve can both potentially provide measure of the IGMF correlation length, provided it lies within the range 10 kpc ? ?B ? 1 Mpc. For correlation lengths outside this range, gamma-ray observations can provide an upper or lower bound on ?B. The latter of the two methods holds great promise in the near future for providing a measurement/constraint using measurements from present/next-generation ?-ray-telescopes. Conclusions: Measurement of the IGMF correlation length will provide an important constraint on its origin. In particular, it will enable to distinguish between an IGMF of galactic wind origin from an IGMF of cosmological origin.

Neronov, A.; Taylor, A. M.; Tchernin, C.; Vovk, I.

2013-06-01

5

Measurement of birefringence correlation length in long, single-mode fibers  

Microsoft Academic Search

Measurements of birefringence correlation length performed on long single-mode telecommunication fibers are reported. The proposed technique relies on the statistical properties of the backscattered-field polarization, which was measured by means of a polarization-sensitive optical time-domain ref lectometer. Experimental results are reported that show good agreement with the underlying theory based on stochastic differential equations. © 2001 Optical Society of America

Andrea Galtarossa; Luca Palmieri; Marco Schiano; Tiziana Tambosso

2001-01-01

6

Measurement of surface plasmon correlation length differences using Fibonacci deterministic hole arrays.  

PubMed

Using terahertz (THz) transmission measurements through two-dimensional Fibonacci deterministic subwavelength hole arrays fabricated in metal foils, we find that the surface plasmon-polariton (SPP) correlation lengths for aperiodic resonances are smaller than those associated with the underlying grid. The enhanced transmission spectra associated with these arrays contain two groups of Fano-type resonances: those related to the two-dimensional Fibonacci structure and those related to the underlying hole grid array upon which the aperiodic Fibonacci array is built. For both groups the destructive interference frequencies at which transmission minima occur closely match prominent reciprocal vectors in the hole array (HA) structure-factor in reciprocal space. However the Fibonacci-related transmission resonances are much weaker than both their calculated Fourier intensity in k space and the grid-related resonances. These differences may arise from the complex, multi-fractal dispersion relations and scattering from the underlying grid arrays. We also systematically studied and compared the transmission resonance strength of Fibonacci HA and periodic HA lattices as a function of the number of holes in the array structure. We found that the Fibonacci-related resonance strengths are an order of magnitude weaker than that of the periodic HA, consistent with the smaller SPP correlation length for the aperiodic structure. PMID:22772220

Nguyen, Tho Duc; Nahata, Ajay; Vardeny, Z Valy

2012-07-01

7

Simultaneous measurement of length, concentration and brightness of single-walled carbon nanotubes with fluorescence correlation spectroscopy  

NASA Astrophysics Data System (ADS)

We report on the application of fluorescence correlation spectroscopy (FCS) to simultaneously measure the brightness, concentration, and length of single-walled carbon nanotubes (SWCNTs). The technique relies on the intrinsic bandgap luminescence of (6,5) chirality semiconducting SWCNTs in the near infra-red (NIR) range and does not require sample labeling. The nanotubes used in this study have been dispersed in solution of single stranded DNA and length fractionated via size exclusion chromatography. The SWCNT length measured by FCS was in excellent agreement with more traditional techniques - polarized dynamic light scattering (DLS) and atomic force microscopy (AFM). The apparent nanotube brightness is shown to grow linearly with the mean nanotube length, having a zero intensity cut-off at 110 nm, implying an exciton diffusion length of 55 nm for SWCNTs dispersed in sodium deoxycholate.

Pristinski, Denis; Khripin, Constantine; Tu, Xiaomin; Zheng, Ming

2011-03-01

8

Measuring Thermodynamic Length  

SciTech Connect

Thermodynamic length is a metric distance between equilibrium thermodynamic states. Among other interesting properties, this metric asymptotically bounds the dissipation induced by a finite time transformation of a thermodynamic system. It is also connected to the Jensen-Shannon divergence, Fisher information, and Rao's entropy differential metric. Therefore, thermodynamic length is of central interestin understanding matter out of equilibrium. In this Letter, we will consider how to denethermodynamic length for a small system described by equilibrium statistical mechanics and how to measure thermodynamic length within a computer simulation. Surprisingly, Bennett's classic acceptance ratio method for measuring free energy differences also measures thermodynamic length.

Crooks, Gavin E

2007-09-07

9

Correlation length of large-scale solar wind velocity fluctuations measured tangent to the Earth's orbit: First results from Stereo  

Microsoft Academic Search

Proton velocity data from identical plasma instruments on board NASA's two Stereo spacecraft are used to investigate the correlation length of large-scale radial velocity fluctuations in the solar wind in the direction tangent to the Earth's orbit. The data cover the period from February 2007 through August 2007, near solar minimum in 2007. Estimates of the spatial correlation function are

J. J. Podesta; A. B. Galvin; C. J. Farrugia

2008-01-01

10

Extended Length Digital Correlator Threshold Circuit.  

National Technical Information Service (NTIS)

An extended length digital correlator threshold circuit for (N . M) -bit correlation using N M-bit correlators is disclosed. For the exemplary case where N=2, the digital correlator threshold circuit comprises: a first circuit for storing a preselected co...

L. M. Leibowitz T. Mai

1992-01-01

11

Overview of bunch length measurements.  

SciTech Connect

An overview of particle and photon beam bunch length measurements is presented in the context of free-electron laser (FEL) challenges. Particle-beam peak current is a critical factor in obtaining adequate FEL gain for both oscillators and self-amplified spontaneous emission (SASE) devices. Since measurement of charge is a standard measurement, the bunch length becomes the key issue for ultrashort bunches. Both time-domain and frequency-domain techniques are presented in the context of using electromagnetic radiation over eight orders of magnitude in wavelength. In addition, the measurement of microbunching in a micropulse is addressed.

Lumpkin, A. H.

1999-02-19

12

Eye dominance and ct measures of occipital length and width  

Microsoft Academic Search

CT measurements of right and left occipital length and width were correlated with eye dominance for 14 men and 27 women. Female subjects demonstrated little relationship between eye dominance and occipital measurements. For male subjects, however, right eye dominance was significantly correlated with increased lengths and widths for both right and left hemispheres on CT slices W, SM, and SM

Suzanne Craft; Ronald A. Yeo

1990-01-01

13

Fundamental correlation lengths of coherent speckle in medical ultrasonic images  

Microsoft Academic Search

Refinements to previous analyses of the natural correlation lengths within simple images and between images to be compounded are presented. Comparison of theoretical and experimental results show very good agreement for the case of Rayleigh scattering media: the correlation length within a simple image is comparable to the resolution cell size; the correlation length between images to be spatially compounded

R. F. Wagner; M. F. Insana; S. W. Smith

1988-01-01

14

Environmental Correlates of Food Chain Length  

Microsoft Academic Search

In 113 community food webs from natural communities, the average and maximal lengths of food chains are independent of primary productivity, contrary to the hypothesis that longer food chains should arise when more energy is available at their base. Environmental variability alone also does not appear to constrain average or maximal chain length. Environments that are three dimensional or solid,

Frederic Briand; Joel E. Cohen

1987-01-01

15

BUNCH LENGTH MEASUREMENTS AT JLAB FEL  

Microsoft Academic Search

The JLab FEL is routinely operated with sub- picosecond bunches. The short bunch length is important for high gain of the FEL. Coherent transition radiation has been used for the bunch length measurements for many years (1). This diagnostic can be used only in the pulsed beam mode. It is our goal to run the FEL with CW beam and

P. Evtushenko; J. Coleman; K. Jordan; J. Michael Klopf; G. Neil; G. P. Williams

16

Ultrasonographic ear length measurement in normal second- and third-trimester fetuses  

Microsoft Academic Search

Objective: We sought to develop a nomogram for fetal ear length measurements from a large population of healthy second- and third-trimester fetuses and to investigate the correlation of fetal ear length with other standard fetal biometry measurements, as follows: biparietal diameter, head circumference, abdominal circumference, femur length, and humerus length. Study Design: Ear length measurement was obtained prospectively in 4240

Usha Chitkara; Lisa Lee; Yasser Y. El-Sayed; R. Harold Holbrook; Daniel A. Bloch; John W. Oehlert; Maurice L. Druzin

2000-01-01

17

Roughness with a finite correlation length in a microtrap  

SciTech Connect

We analyze the effects of roughness in the magnitude of the magnetic field produced by a current carrying microwire, which is caused by the geometric fluctuation of the edge of the wire. The relation between the fluctuation of the trapping potential and the height the atom trap lies above the wire is very well consistent with the experimental data when the colored noise with a finite correlation length is considered. On this basis, we generate the random potential and get the density distribution of the Bose-Einstein condensate (BEC) atoms by solving the Gross-Pitaevskii equation, which coincides well with the experimental image, especially in the number of fragmentations. The results help us further understand the nature of the fluctuation and predict its possible application in the precise measurement.

Wu Muzhi; Zhou Xiaoji; Chen Xuzong [School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China); Liu, W. M. [Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

2010-03-15

18

Correlation lengths of the repulsive one-dimensional Bose gas  

NASA Astrophysics Data System (ADS)

We investigate the large-distance asymptotic behavior of the static density-density and field-field correlation functions in the one-dimensional Bose gas at finite temperature. The asymptotic expansions of the Bose gas correlators are obtained performing a specific continuum limit in the similar low-temperature expansions of the longitudinal and transversal correlation functions of the XXZ spin chain. In the lattice system the correlation lengths are computed as ratios of the largest and next-largest eigenvalues of the XXZ spin chain quantum transfer matrix. In both cases, lattice and continuum, the correlation lengths are expressed in terms of solutions of Yang-Yang type [C. N. Yang and C. P. Yang, J. Math. Phys.JMAPAQ0022-248810.1063/1.1664947 10, 1151 (1969)] nonlinear integral equations which are easily implementable numerically.

Pâ?u, Ovidiu I.; Klümper, Andreas

2013-09-01

19

Turbulent Radial Correlation Lengths in the DIII-D Tokamak  

SciTech Connect

Measurements of the radial correlation length Ar of density fluctuations have been made on the DIII-D tokamak in a variety of L-mode discharges. These measurements span the radial region 0.5 < {rho} < 1 and are found to scale approximately as {rho}{sub {theta},s} or 5-10 {rho}{sub s}. Here {rho}{sub {theta},s} is the poloidal ion Larmor radius calculated using local T{sub e} and poloidal magnetic field and {rho}{sub s} is the same except calculated using the total magnetic field. The {Delta}r data were obtained from a heterodyne reflectometer system. Comparisons to published analytic formulas of Ar have been carried out for a particular discharge condition. The measurements are found to be comparable in magnitude and radial dependence with a slab type formulation of ion temperature gradient (ITG) driven turbulence as well as an electron drift wave turbulence type prediction. Predictions from toroidal ITG and a different slab ITG model were found to be outside the error bars of the measurements. In addition, a detailed comparison to a non-linear gyro-kinetic turbulence code has begun. These and other similar comparisons are believed to be important as they serve to test and benchmark theory and codes as well as to help identify the type(s) of turbulence involved.

T.L. Rhodes; J.-N. Leboeuf; R. Sydora; E.J. Doyle; R.A. Moyer; C.L. Rettig; K.H. Burrell; D.M. Thomas; G.R. McKee; W.A. Peebles

2000-08-01

20

Novel micro interferometer for length measurements  

Microsoft Academic Search

A novel micro interferometer for length and displacement measurements based on sampling an optical standing wave was developed. The interference of two laser beams propagating in opposite direction results in a sinusoidal light intensity profile, which can be detected by thin transparent photodiodes. Two detectors positioned on the optical axis of a standing wave allow bi-directional fringe counting. The operation

H. Stiebig; V. Mandryka; E. Bunte; H.-J. Büchner; K. H. Jun

2004-01-01

21

Measuring the orbit length of the Tevatron  

SciTech Connect

The orbit length in the Tevatron was measured when coasting beam was first obtained. The method was time-of-flight, using a vernier phase comparison between beam pickup signals and a synthesizer sine wave. Some effort was spent making a stable phase detector so that it would not be a limiting factor. The results exhibited a repeatability of a few Hz at 53 MHz, corresponding to a mean radius measurement to 0.1 mm. 5 refs., 4 figs.

Kerns, C.; Kerns, Q.; Miller, H.

1985-06-01

22

Determining correlation and coherence lengths in turbulent boundary layer flight data  

NASA Astrophysics Data System (ADS)

Wall pressure data acquired during flight tests at several flight conditions are analysed and the correlation and coherence lengths of the data reported. It is found that the correlation and coherence lengths are influenced by the origin of the structure producing the pressure and the frequency bandwidth over which the analyses are performed. It is shown how the frequency bandwidth biases the correlation length and how the convection of the pressure field might reduce the coherence measured between sensors. A convected form of the cross correlation and cross spectrum is introduced to compensate for the effects of convection. Coherence lengths measured in the streamwise direction appear much longer than expected. Coherent structures detected using the convected cross correlation do not exhibit an exponential coherent power decay.

Palumbo, Dan

2012-07-01

23

Robust measurement of telomere length in single cells.  

PubMed

Measurement of telomere length currently requires a large population of cells, which masks telomere length heterogeneity in single cells, or requires FISH in metaphase arrested cells, posing technical challenges. A practical method for measuring telomere length in single cells has been lacking. We established a simple and robust approach for single-cell telomere length measurement (SCT-pqPCR). We first optimized a multiplex preamplification specific for telomeres and reference genes from individual cells, such that the amplicon provides a consistent ratio (T/R) of telomeres (T) to the reference genes (R) by quantitative PCR (qPCR). The average T/R ratio of multiple single cells corresponded closely to that of a given cell population measured by regular qPCR, and correlated with those of telomere restriction fragments (TRF) and quantitative FISH measurements. Furthermore, SCT-pqPCR detected the telomere length for quiescent cells that are inaccessible by quantitative FISH. The reliability of SCT-pqPCR also was confirmed using sister cells from two cell embryos. Telomere length heterogeneity was identified by SCT-pqPCR among cells of various human and mouse cell types. We found that the T/R values of human fibroblasts at later passages and from old donors were lower and more heterogeneous than those of early passages and from young donors, that cancer cell lines show heterogeneous telomere lengths, that human oocytes and polar bodies have nearly identical telomere lengths, and that the telomere lengths progressively increase from the zygote, two-cell to four-cell embryo. This method will facilitate understanding of telomere heterogeneity and its role in tumorigenesis, aging, and associated diseases. PMID:23661059

Wang, Fang; Pan, Xinghua; Kalmbach, Keri; Seth-Smith, Michelle L; Ye, Xiaoying; Antumes, Danielle M F; Yin, Yu; Liu, Lin; Keefe, David L; Weissman, Sherman M

2013-05-09

24

Polyelectrolyte persistence length: Attractive effect of counterion correlations and fluctuations  

NASA Astrophysics Data System (ADS)

The persistence length of a single, strongly charged, stiff polyelectrolyte chain is investigated theoretically. Path integral formulation is used to obtain the effective electrostatic interaction between the monomers. We find significant deviations from the classical Odijk, Skolnick and Fixman (OSF) result. An induced attraction between monomers is due to thermal fluctuations and correlations between bound counterions. The electrostatic persistence length is found to be smaller than the OSF value and indicates a possible mechanical instability (collapse) for highly charged polyelectrolytes with multivalent counterions. In addition, we calculate the amount of condensed counterions on a slightly bent polyelectrolyte. More counterions are found to be adsorbed as compared to the Manning condensation on a cylinder.

Ariel, G.; Andelman, D.

2003-01-01

25

Variation in body length measurement of Euphausia superba Dana  

Microsoft Academic Search

Various body length measurements were made on freshly captured and preserved Euphausia superba Dana. Functions were calculated to describe the relationship of various length measurements to one another for fresh animals. In sexually immature animals length measurements were closely related, but variations in the relationship of standard length to carapace length were found for both mature male and female animals.

D. G. M. Miller

1983-01-01

26

Anisotropic correlation length in the eight-vertex model  

NASA Astrophysics Data System (ADS)

We investigate the directional dependence (or anisotropy) of the correlation length of the eight-vertex model by a method which introduces the shift operator into the usual transfer matrix argument. For a given x (0 < x < 1) there are two cases with respect to a parameter q. In the case 0 < q < x3, the anisotropic correlation length (ACL) is independent of q. Noting that the eight-vertex model factors into two Ising lattices in the q -> x4 limit, we can directly relate the ACL to that of the square lattice Ising model. When x3 < q < x2, the ACL depends onq . Using an algebraic curve, we show that the ACL in this case is connected with that of the Ising model on a 4-8 (or Union Jack) lattice. We suggest that a wide class of models have essentially the same ACL as the eight-vertex model has.

Fujimoto, Masafumi

1996-02-01

27

Bunch Length Measurements using Coherent Radiation  

SciTech Connect

The accelerating field that can be obtained in a beam-driven plasma wakefield accelerator depends on the current of the electron beam that excites the wake. In the E-167 experiment, a peak current above 10 kA will be delivered at a particle energy of 28 GeV. The bunch has a length of a few ten micrometers and several methods are used to measure its longitudinal profile. Among these, autocorrelation of coherent transition radiation (CTR) is employed. The beam passes a thin metallic foil, where it emits transition radiation. For wavelengths greater than the bunch length, this transition radiation is emitted coherently. This amplifies the long-wavelength part of the spectrum. A scanning Michelson interferometer is used to autocorrelate the CTR. However, this method requires the contribution of many bunches to build an autocorrelation trace. The measurement is influenced by the transmission characteristics of the vacuum window and beam splitter. We present here an analysis of materials, as well as possible layouts for a single shot CTR autocorrelator.

Ischebeck, Rasmus; Barnes, Christopher; Blumenfeld, Ian; Decker, Franz-Josef; Hogan, Mark; Iverson, Richard H.; Krejcik, Patrick; Siemann, Robert H.; Walz, Dieter; /SLAC; Kirby, Neil; /Stanford U., Phys. Dept.; Clayton, Chris; Huang, Chengkun; Johnson, Devon K.; Lu, Wei; Marsh, Ken; /UCLA; Deng, Suzhi; Oz, Erdem; /Southern California U.

2005-06-24

28

Electron correlation and bond-length alternation in polyene chains  

SciTech Connect

The PPP model is used to consider polyene chains in the ground state with allowance for the interaction of the electrons with core deformations. The stationary wave functions describing the electron correlations are derived as antisymmetrized products of two-electron functions optimized with respect to all variational parameters. The bond-length alternation can be related to the characteristics of the electron-electron potential; one can allow approximately for the effects of interaction between electrons at adjacent centers on the alternation by renormalizing the parameters in the Hubbard model.

Kuprievich, V.A.

1986-11-01

29

Path lengths, correlations, and centrality in temporal networks  

NASA Astrophysics Data System (ADS)

In temporal networks, where nodes interact via sequences of temporary events, information or resources can only flow through paths that follow the time ordering of events. Such temporal paths play a crucial role in dynamic processes. However, since networks have so far been usually considered static or quasistatic, the properties of temporal paths are not yet well understood. Building on a definition and algorithmic implementation of the average temporal distance between nodes, we study temporal paths in empirical networks of human communication and air transport. Although temporal distances correlate with static graph distances, there is a large spread, and nodes that appear close from the static network view may be connected via slow paths or not at all. Differences between static and temporal properties are further highlighted in studies of the temporal closeness centrality. In addition, correlations and heterogeneities in the underlying event sequences affect temporal path lengths, increasing temporal distances in communication networks and decreasing them in the air transport network.

Pan, Raj Kumar; Saramäki, Jari

2011-07-01

30

Parallel and perpendicular turbulence correlation length in the TJ-II Stellarator  

NASA Astrophysics Data System (ADS)

Long-range correlations were measured using two remote reciprocating Langmuir probe systems at TJ-II. The influence of the rotational transform on the correlation was studied by scanning the magnetic configuration. A simple drift-wave correlation model, assuming an exponential decay of the correlation with different correlation lengths in the directions parallel and perpendicular to the field lines, was found to describe the observations well at low densities. The experiment was repeated at gradually higher densities, and an additional correlation was detected at a critical value of the density. In accordance with previous work, this additional correlation was ascribed to zonal flows associated with a confinement transition. Thus, the total long-range correlation is found to be a sum of the drift wave and zonal flow contributions.

van Milligen, B. Ph.; Lopez Fraguas, A.; Pedrosa, M. A.; Hidalgo, C.; Martín de Aguilera, A.; Ascasíbar, E.

2013-09-01

31

Path lengths, correlations, and centrality in temporal networks.  

PubMed

In temporal networks, where nodes interact via sequences of temporary events, information or resources can only flow through paths that follow the time ordering of events. Such temporal paths play a crucial role in dynamic processes. However, since networks have so far been usually considered static or quasistatic, the properties of temporal paths are not yet well understood. Building on a definition and algorithmic implementation of the average temporal distance between nodes, we study temporal paths in empirical networks of human communication and air transport. Although temporal distances correlate with static graph distances, there is a large spread, and nodes that appear close from the static network view may be connected via slow paths or not at all. Differences between static and temporal properties are further highlighted in studies of the temporal closeness centrality. In addition, correlations and heterogeneities in the underlying event sequences affect temporal path lengths, increasing temporal distances in communication networks and decreasing them in the air transport network. PMID:21867255

Pan, Raj Kumar; Saramäki, Jari

2011-07-18

32

Direct measure of quantum correlation  

SciTech Connect

The quantumness of the correlation known as quantum correlation is usually measured by quantum discord. So far various quantum discords can be roughly understood as indirect measure by some special discrepancy of two quantities. We present a direct measure of quantum correlation by revealing the difference between the structures of classically and quantum correlated states. Our measure explicitly includes the contributions of the inseparability and local nonorthogonality of the eigenvectors of a density matrix. Besides its relatively easy computability, our measure can provide a unified understanding of quantum correlation of all the present versions.

Yu, Chang-shui [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Zhao, Haiqing [School of Science, Dalian Jiaotong University, Dalian 116028 (China)

2011-12-15

33

Evaluation of the normal fetal kidney length and its correlation with gestational age.  

PubMed

A true estimation of gestational age (GA) plays an important role in quality maternity care and scheduling the labor date. This study aimed to evaluate the normal fetal kidney length (KL) and its correlation with GA. A cross-sectional study on 92 pregnant women between 8th and 10th week of gestation with normal singleton pregnancy underwent standard ultrasound fetal biometry and kidney length measurement. univariate and multivariate linear regression analysis was used to create a predictive equation to estimate GA on the KL and fetobiometry parameters. A significant correlation was found between GA and KL (r=0.83, P<0.002). The best GA predictor was obtained by combining head circumference, fetal biparietal diameter, femur length and KL with a standard error (SE) about 14.2 days. Our findings showed that KL measurements combination with other fetal biometric parameters could predict age of pregnancy with a better precision. PMID:23737313

Seilanian Toosi, Farrokh; Rezaie-Delui, Hossein

2013-05-30

34

Accurate planar area and contour length measurement  

Microsoft Academic Search

This paper describes a technique for accurately estimating the area and contour length of a planar non-polygonal region in the scene. The approach taken is to formulate a continuous model of the boundary of the region in the scene and use the image data to estimate the parameters of the model. The required information is then extracted from the model

R. J. Valkenburg; R. Kakarala

1997-01-01

35

Correlations of Length Spectra for Negatively Curved Manifolds  

NASA Astrophysics Data System (ADS)

In this paper we obtain asymptotic estimates for pairs of closed geodesics on negatively curved manifolds, the differences of whose lengths lie in a prescribed family of shrinking intervals, where the geodesics are ordered with respect to a discrete length. In certain cases, this discrete length can be taken to be the word length with respect to a set of generators for the fundamental group.

Pollicott, Mark; Sharp, Richard

2013-04-01

36

Histomorphometric Study of the Root Apex of Mandibular Premolar Teeth: An Attempt to Correlate Working Length Measured with Electronic and Radiograph Methods to Various Anatomic Positions in the Apical Portion of the Canal  

Microsoft Academic Search

One aim of this study was to attempt to relate the position of the cementodentinal junction (CDJ) and the apical constriction to that of the apical foramen in mandibular premolars, as well as to measure the canal diameter at these various points. Another aim was to evaluate how electronic working length determination by Root ZX and radiographic method of working

Ehab E. Hassanien; Abeer Hashem; Henry Chalfin

2008-01-01

37

Measuring and interpreting neuronal correlations  

PubMed Central

Mounting evidence suggests that understanding how the brain encodes information and performs computations will require studying correlations between neurons. The recent advent of recording techniques such as multielectrode arrays and two-photon imaging has made it easier to measure correlations, opening the door to detailed exploration of their properties and contributions to cortical processing. Studies to date, however, have reported discrepant findings, providing a confusing picture. Here, we briefly review these studies and conduct simulations to explore the influence of several experimental and physiological factors on correlation measurements. Differences in response strength, the time window over which spikes are counted, spike sorting conventions, and internal states can all dramatically affect measured correlations and systematically bias estimates. Given these complicating factors, we offer guidelines for interpreting correlation data and a discussion of how best to evaluate the impact of correlations on cortical processing.

Cohen, Marlene R.; Kohn, Adam

2013-01-01

38

Measurements of Flame Lengths Under Ceilings,  

National Technical Information Service (NTIS)

Measurements of luminous flame extensions beneath ceilings under steady burning conditions are presented. Tests were conducted using both axisymmetric and corner-wall-ceiling configurations for a range of energy supply rates up to 400 kW and burner-to-cei...

D. Gross

1988-01-01

39

Mach-Zehnder Modulator Arm-Length-Mismatch Measurement Technique  

NASA Astrophysics Data System (ADS)

This paper describes a robust measurement technique for determining the effective length mismatch of the two arms of a Mach-Zehnder modulator (MZM), based on its broad-band filter characteristics. The proposed method involves measuring the Vpi (lambda), n(lambda), and transfer function of a modulator at various externally applied bias points. This mismatch measurement technique is applied to a packaged polymer rib waveguide MZM, and it is shown that it has an arm-length mismatch of 1.9 ?m. Poling-induced writing is then proposed as a fabrication technique that can consistently produce polymer MZMs with arm-length-mismatch values less than 2 ?m.

Geary, Kevin; Kim, Seong-Ku; Seo, Byoung-Joon; Fetterman, Harold R.

2005-03-01

40

Interobserver reliability of digital and endovaginal ultrasonographic cervical length measurements  

Microsoft Academic Search

OBJECTIVE: Our purpose was to prospectively evaluate the interobserver reliability of digital and endovaginal ultrasonographic cervical length measurements.STUDY DESIGN: Forty-three women were recruited from our antepartum clinic to participate in this study. Two independent and blinded digital cervical examinations were performed by the first author and a second examiner. Instructions were given to estimate the cervical length in millimeters. After

Jay Goldberg; Roger B. Newman; Philip F. Rust

1997-01-01

41

Interference comparator for certifying engraved and end length measures  

SciTech Connect

This paper describes the use of engraved and end measures with interference comparators for absolute length measurement by means of coherent sources stabilized on natural reference lines and whose radiation frequencies are certified. The use of a coherent source in an interference comparator requires a radical change in the design since the measurement methods used with multiwave spectral lamps in previous designs are very different from those in laser interferometry. The authors consider the design of the interference comparator. The studies show that the main contribution to the error in transmitting the length unit to material engraved measures comes from the errors in positioning the engraving and measuring the measure temperature.

Bolonin, A.A.; Fedorin, V.L.; Khavinson, L.F.; Shur, V.L.

1985-04-01

42

Far-from-equilibrium measurements of thermodynamic length  

SciTech Connect

Thermodynamic length is a path function that generalizes the notion of length to the surface of thermodynamic states. Here, we show how to measure thermodynamic length in far-from-equilibrium experiments using the work fluctuation relations. For these microscopic systems, it proves necessary to define the thermodynamic length in terms of the Fisher information. Consequently, the thermodynamic length can be directly related to the magnitude of fluctuations about equilibrium. The work fluctuation relations link the work and the free energy change during an external perturbation on a system. We use this result to determine equilibrium averages at intermediate points of the protocol in which the system is out-of-equilibrium. This allows us to extend Bennett's method to determine the potential of mean force, as well as the thermodynamic length, in single molecule experiments.

Feng, Edward H.; Crooks, Gavin E.

2008-11-05

43

The feather-length of small passerines: a measurement for wing-length in live birds and museum skins  

Microsoft Academic Search

Wing-length is difficult to measure reproducibly, and to compare between live birds and museum skins. Recently the length of Primary 8 was suggested as a measure of wing-length in live small passerines; smaller variation was found between observers than in wing-length.This paper examines which feather-length out of Primaries 1 and 6–¸9 best represents wing-length in 51 passerine species. It was

Lukas Jenni; Rafael Winkler

1989-01-01

44

Coherent Transition Radiation to Measure the SLAC Electron Bunch Length  

SciTech Connect

Coherent transition radiation is used to measure the length of the ultra-short electron bunches available at the Stanford Linear Accelerator Center. The results and the limitations of the method are described.

Muggli, P.; /Southern California U.; Hogan, M.J.; Barnes, C.D.; Walz, D.; Krejcik, P.; Siemann, R.H.; /SLAC

2005-05-13

45

Significant correlation of species longevity with DNA double strand break recognition but not with telomere length.  

PubMed

The identification of the cellular mechanisms responsible for the wide differences in species lifespan remains one of the major unsolved problems of the biology of aging. We measured the capacity of nuclear protein to recognize DNA double strand breaks (DSBs) and telomere length of skin fibroblasts derived from mammalian species that exhibit wide differences in longevity. Our results indicate DNA DSB recognition increases exponentially with longevity. Further, an analysis of the level of Ku80 protein in human, cow, and mouse suggests that Ku levels vary dramatically between species and these levels are strongly correlated with longevity. In contrast mean telomere length appears to decrease with increasing longevity of the species, although not significantly. These findings suggest that an enhanced ability to bind to DNA ends may be important for longevity. A number of possible roles for increased levels of Ku and DNA-PKcs are discussed. PMID:19896964

Lorenzini, Antonello; Johnson, F Brad; Oliver, Anthony; Tresini, Maria; Smith, Jasmine S; Hdeib, Mona; Sell, Christian; Cristofalo, Vincent J; Stamato, Thomas D

46

In vivo myograph measurement of muscle contraction at optimal length  

PubMed Central

Background Current devices for measuring muscle contraction in vivo have limited accuracy in establishing and re-establishing the optimum muscle length. They are variable in the reproducibility to determine the muscle contraction at this length, and often do not maintain precise conditions during the examination. Consequently, for clinical testing only semi-quantitative methods have been used. Methods We present a newly developed myograph, an accurate measuring device for muscle contraction, consisting of three elements. Firstly, an element for adjusting the axle of the device and the physiological axis of muscle contraction; secondly, an element to accurately position and reposition the extremity of the muscle; and thirdly, an element for the progressive pre-stretching and isometric locking of the target muscle. Thus it is possible to examine individual in vivo muscles in every pre-stretched, specified position, to maintain constant muscle-length conditions, and to accurately re-establish the conditions of the measurement process at later sessions. Results In a sequence of experiments the force of contraction of the muscle at differing stretching lengths were recorded and the forces determined. The optimum muscle length for maximal force of contraction was established. In a following sequence of experiments with smaller graduations around this optimal stretching length an increasingly accurate optimum muscle length for maximal force of contraction was determined. This optimum length was also accurately re-established at later sessions. Conclusion We have introduced a new technical solution for valid, reproducible in vivo force measurements on every possible point of the stretching curve. Thus it should be possible to study the muscle contraction in vivo to the same level of accuracy as is achieved in tests with in vitro organ preparations.

Rahe-Meyer, Niels; Weilbach, Christian; Karst, Matthias; Pawlak, Matthias; Ahmed, Aminul; Piepenbrock, Siegfried; Winterhalter, Michael

2007-01-01

47

Scapula length measurement for assessment of fetal growth and development  

Microsoft Academic Search

To determine the value of prenatal ultrasonographic scapula measurements for fetal growth and development as an adjunct to assessing in utero development, a prospective study of ultrasonography was conducted in 343 pregnant women with uneventful pregnancies with gestational ages from 16 to 41 weeks, and several biometric measurements were obtained. The relationships of scapula length with gestational age and with

Gülçin Dilmen; Nilgün Öztürk Turhan; Mete Fuad Toppare; Neslihan Seçkin; Muazzez Öztürk; Eflatun Göksin

1995-01-01

48

Axial eye-length measurement by wavelength-shift interferometry.  

PubMed

A simplified noncontact measuring technique for axial eye length was developed. According to this method, the wavelength shift of a single-mode laser-diode beam that is irradiated onto the eyeball causes a phase shift in the interference fringes of reflections from the retina and the cornea. Then the optical distance between the cornea and the retina is obtained from the phase-shift measurement. High-speed axial eye-length measurements can be performed by using a laser diode on a pulse-modulation drive and signals from the reference light path as an analog-to-digital-conversion trigger. Compared with the technique that uses partially coherent light, this technique is inferior in terms of measurement accuracy but superior in its wide, measurable range of 16-32 mm. The results of measurements of 21 adults showed that 2 standard deviations of measurement was 2 sigma = +/- 0.11 mm. PMID:8350154

Sekine, A; Minegishi, I; Koizumi, H

1993-07-01

49

Asteroid hyalosis and axial length measurement using automated biometry.  

PubMed

Accurate axial length measurements are needed before intraocular lens implantation in patients with asteroid hyalosis requiring cataract extraction. We suspected that falsely short axial length measurements may be obtained using automated A-scan biometry when we found an automated measurement of 15.90 mm in a patient with severe unilateral asteroid hyalosis. A manual biometry measurement of 21.90 mm was obtained for comparison; this was within 0.2 mm of the manual reading in the opposite uninvolved eye. A case-control study was performed on 20 unilateral asteroid hyalosis subjects using the uninvolved eye as the control, comparing automated biometry and manual A-scan biometry to assess the effect of asteroid hyalosis on automated biometry measurements. Five subjects (25%) with asteroid hyalosis had falsely short axial length measurements of more than 1.00 mm using automated biometry. This would result in more than 2.50 diopters of error in the implanted lens power. This case-control study demonstrates that falsely short axial length measurements may be obtained using automated biometry in patients with asteroid hyalosis, leading to significant error in intraocular lens power calculations. PMID:2040975

Allison, K L; Price, J; Odin, L

1991-03-01

50

EARLINET Correlative Measurements For CALIPSO  

NASA Astrophysics Data System (ADS)

EARLINET, the European Aerosol Research Lidar Network, is the first aerosol lidar network, established in 2000, with the main goal to provide a comprehensive, quantitative, and statistically significant data base for the aerosol distribution on a continental scale. At present, 24 stations distributed over Europe are part of the network: 10 single backscatter lidar stations, 7 Raman lidar stations with the Raman channel in the UV for independent measurements of aerosol extinction and backscatter, and 7 multi-wavelength Raman lidar stations (elastic channel at 1064 nm, 532 nm, 355 nm, Raman channels at 532 nm and 355 nm, plus depolarization channel at 532 nm) for the retrieval of aerosol microphysical properties. The network activity is based on scheduled measurements, a rigorous quality assurance program addressing both instruments and evaluation algorithms, and a standardized data exchange format. In order to collect unbiased data, all the network stations perform measurements simultaneously at three fixed dates a week. Lidar observations are performed on a regular schedule of one daytime measurement on Monday around noon, when the boundary layer is usually well developed, and two night time measurements per week (Monday and Thursday), with low background light, in order to perform Raman extinction measurements. Additional network measurements are performed to address specifically important processes that are localized either in space or time, like Saharan dust outbreaks, forest fires, volcanic eruptions, photochemical smog. EARLINET represents an optimal tool to validate CALIPSO lidar data and to provide the necessary information to fully exploit the information from that mission. In particular, aerosol extinction measurements, provided by the network, will be important for the aerosol retrievals from the CALIPSO backscatter lidar. EARLINET started correlative measurements for CALIPSO since 14 June 2006. These EARLINET correlative measurements are performed at each station in coincidence with CALIPSO overpasses. Each observation lasts for a minimum of 1 hour centered around the overpass time, longer record of measurements are performed for special case studies (Saharan dust layers, forest fires, long range transport, etc.). Backtrajectory analysis will be also used to quantitatively study comparisons between CALIPSO and EARLINET observations. EARLINET correlative measurements plan for CALIPSO, and first results will be presented. ACKNOWLEDGMENTS The financial support for the improvement of the EARLINET infrastructure by the European Commission under grant RICA-025991 is gratefully acknowledged. The authors also thank the German Weather Service for the air mass backtrajectory analysis.

Pappalardo, G.

2006-12-01

51

Intra-operative measurement of surgical lengths of the rectum and the peritoneal reflection in Korean.  

PubMed

The lengths of the surgical rectum and peritoneal reflection were important factors in treatment modality of rectal tumor. To evaluate the surgical length of rectum, we measured the length of the peritoneal reflections, sacral promontory and termination of the taenia coli from the anal verge by rigid sigmoidoscope in 23 male and 23 females during operation. The mean lengths of the sacral promontory were 16.5+/- 2.2 cm and 16.1+/-2.2 cm in the males and females, respectively. As for the peritoneal reflection, the results were anterior (8.8+/-2.2 cm, 8.1+/-1.7 cm), lateral (10.8+/-2.7 cm, 11.4+/-1.9 cm) and posterior (13.8+/-2.5 cm, 14.0+/-1.9 cm), respectively. There were no statistically significant differences between male and female. And only height had a correlation with the length of sacral promontory both in male and female (p=0.015 and p=0.018, respectively). For all the estimated lengths, the length of the sacral promontory had a correlation with the lengths of the anterior (p<0.001 and p=0.001) and posterior (p<0.001 and p<0.001) peritoneal reflections in males and females, respectively. We suggest that the intra-operative lengths of the rectum and peritoneal reflection will be useful information for treatment modality of rectal tumor clinically in Korean. PMID:19119443

Yun, Hae Ran; Chun, Ho-Kyung; Lee, Won Suk; Cho, Yong Beom; Yun, Seong Hyeon; Lee, Woo Yong

2008-12-24

52

Intra-operative Measurement of Surgical Lengths of the Rectum and the Peritoneal Reflection in Korean  

PubMed Central

The lengths of the surgical rectum and peritoneal reflection were important factors in treatment modality of rectal tumor. To evaluate the surgical length of rectum, we measured the length of the peritoneal reflections, sacral promontory and termination of the taenia coli from the anal verge by rigid sigmoidoscope in 23 male and 23 females during operation. The mean lengths of the sacral promontory were 16.5± 2.2 cm and 16.1±2.2 cm in the males and females, respectively. As for the peritoneal reflection, the results were anterior (8.8±2.2 cm, 8.1±1.7 cm), lateral (10.8±2.7 cm, 11.4±1.9 cm) and posterior (13.8±2.5 cm, 14.0±1.9 cm), respectively. There were no statistically significant differences between male and female. And only height had a correlation with the length of sacral promontory both in male and female (p=0.015 and p=0.018, respectively). For all the estimated lengths, the length of the sacral promontory had a correlation with the lengths of the anterior (p<0.001 and p=0.001) and posterior (p<0.001 and p<0.001) peritoneal reflections in males and females, respectively. We suggest that the intra-operative lengths of the rectum and peritoneal reflection will be useful information for treatment modality of rectal tumor clinically in Korean.

Yun, Hae Ran; Lee, Won Suk; Cho, Yong Beom; Yun, Seong Hyeon; Lee, Woo Yong

2008-01-01

53

[Laser optic measurements of the axial length of the eye].  

PubMed

A new method has been developed for determining the axial length of the human eye. This method is based on laser interferometry with partially coherent light emitted by a multimode semiconductor laser diode. The measurement procedure is as follows. The subject looks into the laser beam (wavelength approximately equal to 780 nm, power approximately equal to 100 microW), which appears as a red spot. Hence the laser beam acts as a fixation target and measuring beam. This beam passes a Fabry-Perot interferometer in front of the eye. Reflected beams are generated at the cornea and retina. Since the coherence length of the laser used (approximately equal to 25 microns) is less than the difference in path length of the two reflected beams, they will usually not interfere with each other. However, if the distance between the interferometer plates is equal to the optical length of the eye, an interference pattern can be observed. (This is due to a second illuminating beam, which is generated by the interferometer and delayed by two times the interferometer plate distance.) During measurement, the plates are displaced relative to each other until the interference pattern is observed. At this point the plate distance, which can readily be measured, is equal to the optical eye length. This method has several advantages in comparison with the usual ultrasonic technique: it is a non-contact method; no anesthesia is needed; the optical eye length is determined directly; no assumptions need be made about sound velocities in the different eye media. High longitudinal and transversal resolution is achieved (10 microns or better possible). The first measurements obtained with the optical method were compared with the results yielded by the ultrasound technique.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2737574

Hitzenberger, C; Mengedoht, K; Fercher, A F

1989-01-01

54

Critical point coupling in liquid helium and the significance of the correlation length  

NASA Astrophysics Data System (ADS)

[1]( #1 ?m )^3 Recent measurements of liquid helium confined to 2 boxes connected through a 33 nm film have shown coupling effects between boxes spaced distances much larger than the correlation length ?(t,L)[1,2] and proximity effects on the connecting film[3]. An analysis of data suggests that ?(t,L) is the relevant parameter in these effects. This dependence on ?(t,L) is used to argue that the enhancement in the specific heat due to coupling is a reflection of the finite-size correlation length in the boxes and hence its scaling function. All this raises some profound questions about our physical understanding of ?(t,L). [4pt] [1] Perron J K, Kimball M O, Mooney K P and Gasparini F M 2010 Nat. Phys./ 6 499--502[0pt] [2] Perron J K, and Gasparini F M 2011 submitted to PNAS/[0pt] [3] Perron J K, and Gasparini F M 2011 to be published in JPCS/

Perron, Justin K.; Thomson, Stephen R. D.; Gasparini, Francis M.

2012-02-01

55

CORRELATION OF H-MODE BARRIER WIDTH AND NEUTRAL PENETRATION LENGTH  

SciTech Connect

OAK A271 CORRELATION OF H-MODE BARRIER WIDTH AND NEUTRAL PENETRATION LENGTH. Pedestal studies in DIII-D find a good correlation between the width of the H-mode density barrier and the neutral penetration length. These results are obtained by comparing experimental density profiles to the predictions of an analytic model for the profile, obtained from the particle continuity equations for electrons and deuterium atoms. In its range of validity (edge temperature between 40-500 eV), the analytic model quantitatively predicts the observed decrease of the width as the pedestal density increases, the observed strong increase of the gradient of the density as the pedestal density increases and the observation that L-mode and H-mode profiles with the same pedestal density have very similar shapes. The width of the density barrier, measured from the edge of the electron temperature barrier, is the lower limit for the observed width of the temperature barrier. These results support the hypothesis that particle fueling provides the dominant control for the size of the H-mode transport barrier.

GROEBNER,RJ; MAHDAVI,MA; LEONARD,AW; OSBORNE,TH; WOLF,NS; PORTER,GD; STANGEBY,PC; BROOKS,NH; COLCHIN,RJ; HEIDBRINK,WW; LUCE,TC; MCKEE,GR; OWEN,LW; WANG,G; WHYTE,DG

2002-09-01

56

CORRELATION OF H-MODE BARRIER WIDTH AND NEUTRAL PENTRATION LENGTH  

SciTech Connect

OAK A271 CORRELATION OF H-MODE BARRIER WIDTH AND NEUTRAL PENTRATION LENGTH. Pedestal studies in DIII-D find a good correlation between the width of the region of steep gradient in the H-mode density and the neutral penetration length. These results are obtained by comparing experimental density profiles to the predictions of an analytic model for the profile, obtained from the particle continuity equations for electrons and deuterium atoms. In its range of validity (edge temperature between 40-500 eV), the analytic model quantitatively predicts the observed decrease of the width as the pedestal density increases, the observed strong increase of the gradient of the density as the pedestal density increases and the observation that L-mode and H-mode profiles with the same pedestal density have very similar shapes. The width of the density barrier, measured from the edge of the electron temperature barrier, is the lower limit for the observed width of the temperature barrier. These results support the hypothesis that particle fueling provides a dominant control for the size of the H-mode transport barrier.

GROEBNER,RJ; MAHDAVI,MA; LEONARD,AW; OSBORNE,TH; WOLF,NS; PORTER,GD; STANGEBY,PC; BROOKS,NH; COLCHIN,RJ; HEIDBRINK,WW; LUCE,TC; MCKEE,GR; OWEN,LW; WANG,G; WHYTE,DG

2002-09-01

57

50 CFR Appendix C to Part 622 - Fish Length Measurements  

Code of Federal Regulations, 2012 CFR

...MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF, AND SOUTH ATLANTIC Pt. 622, App. C Appendix C to Part 622âFish Length Measurements ER03JY96.000 Figure 1 of Appendix C...

2012-10-01

58

Subpicosecond bunch length measurement at the TESLA test facility  

Microsoft Academic Search

Sub-picosecond electron bunches are required for the operation of future VUV and X-ray Free Electron Lasers. A streak camera, a Martin–Puplett interferometer and a longitudinal phase space rotation method have been applied at the TESLA Test Facility linac to measure electron bunch lengths.

M. Geitz; G. Schmidt; P. Schmüser; G. v. Walter

2000-01-01

59

Thin transparent pin-photodiodes for length measurements  

Microsoft Academic Search

We present new interferometers for length measurements based on sampling an optical standing wave. The interference of two laser beams propagating in opposite direction results in a sinusoidal light intensity profile. Thin transparent pin-photodiodes based on amorphous silicon and deposited on a glass substrate enable the detection of this intensity profile. Introducing the detectors into the standing wave, photocurrents according

E Bunte; V Mandryka; K. H Jun; H.-J Büchner; G Jäger; H Stiebig

2004-01-01

60

LIL filtering lenses back focus length absolute measurement  

Microsoft Academic Search

As part of the LIL (Ligne d'Integration Laser) and LMJ (Laser Megajoule) projects, CEA\\/CESTA and SAGEM company have carried out an accurate metrology of the back focus length of filtering lenses. These measurements should enable us to make up for a lack of focus adjustment on the laser and to correctly position these lenses. Three different lenses have been characterized:

Jean-Christophe Poncetta; Vincent Beau; Genevieve Chabassier; Jacques F. Rodolfo; Remi Bourgois; C. Hurst; Francois Houbre

2003-01-01

61

Molecular mass dependence of point-to-set correlation length scale in polymers  

NASA Astrophysics Data System (ADS)

We use a recently proposed metric, termed the point-to-set correlation functions, to probe the molecular weight dependence of the relevant static length scales in glass-forming oligomeric chain liquids of 4, 5, 8, and 10 repeat units. In agreement with the results for simple, monatomic fluids, we find that static length scales of the oligomers increase monotonically when the temperature is lowered towards the glass transition temperature of the fluid. More interestingly, the static length scale increases with increasing chain length. Within the bounds of error in our simulations, the static length scale appears to scale as the radius of gyration of the oligomer, but with a prefactor, which is much larger than unity and which grows with the temperature. The preceding behavior contrasts with the length scales extracted from the radial distribution function of the oligomer system, which is practically independent of the chain length.

Hanson, Ben; Pryamitsyn, Victor; Ganesan, Venkat

2012-08-01

62

LIL filtering lenses back focus length absolute measurement  

NASA Astrophysics Data System (ADS)

As part of the LIL (Ligne d'Integration Laser) and LMJ (Laser Megajoule) projects, CEA/CESTA and SAGEM company have carried out an accurate metrology of the back focus length of filtering lenses. These measurements should enable us to make up for a lack of focus adjustment on the laser and to correctly position these lenses. Three different lenses have been characterized: • Lenses L1 and L2 with a back focus length of 10 m (aperture of F/16). Uncertainty is estimated at +/-1,3 mm. • Lens L3 with a back focus length of 26 m (aperture of F/43). Uncertainty is estimated at +/-5,3 mm. To achieve these measurements, 4 methods have been used: (1) Measurement of the curvature radius of each side on a Coordinate Measuring Machine and index homogeneity characterization before polishing. (2) Interferometric measurement with a reference spherical mirror. (3) Interferometric measurement using a lens side as a reference spherical mirror with a flat mirror. (4) Interferometric measurement by closing the cavity at the top of the lens back side. Uncertainty calculation has been done for each method.

Poncetta, Jean-Christophe; Beau, Vincent; Chabassier, Genevieve; Rodolfo, Jacques F.; Bourgois, Remi; Hurst, C.; Houbre, Francois

2003-11-01

63

Alignment techniques required by precise measurement of effective focal length  

NASA Astrophysics Data System (ADS)

The characteristics of false color imagery produced by instrumentation on earth resource mapping satellites are examined. The spatial fidelity of the imagery is dependent upon the geometric accuracy (GA) and the band-to-band registration (BBR) with which the telescope instrument is assembled. BBR and GA require knowledge of telescope effective focal length (EFL) to one part in 10,000 in order that the next generation of earth mappers be able to carry out their missions. The basis for this level of precision is briefly considered, and a description is given of the means by which such precise EFL measurements have been carried out. Attention is given to accuracy requirements, the technique used to measure effective focal length, possible sources of error in the EFL measurement, approaches for eliminating errors, and the results of the efforts to control measurement errors in EFL determinations.

Wise, T. D.

1980-01-01

64

Comparing dynamic correlation lengths from an approximation to the four-point dynamic susceptibility and from the picosecond vibrational dynamics  

NASA Astrophysics Data System (ADS)

Recently an alternative approach to the determination of dynamic correlation lengths ? for supercooled liquids, based on the properties of the slow (picosecond) vibrational dynamics, was carried out [Hong, Novikov, and Sokolov, Phys. Rev. EPLEEE81063-651X10.1103/PhysRevE.83.061508 83, 061508 (2011)]. Although these vibrational measurements are typically conducted well below the glass transition temperature, the liquid is frozen at Tg, whereby structural correlations, density variations, etc., manifested at low temperatures as spatial fluctuations of local elastic constants, can be related to a dynamic heterogeneity length scale for the liquid state. We compare ? from this method to values calculated using an approximation to the four-point dynamic susceptibility. For 26 different materials we find good correlation between the two measures; moreover, the pressure dependences are consistent within the large experimental error. However, ? from Boson peak measurements above Tg have a different, and unrealistic, temperature dependence.

Fragiadakis, D.; Casalini, R.; Roland, C. M.

2011-10-01

65

Reliability of fetal nasal bone length measurement at 11-14 weeks of gestation  

PubMed Central

Background Nasal bone assessment has been incorporated into Down syndrome screening in first trimester. Several studies have established the normal reference values for fetal nasal bone length in the first trimester, which were found to be varied by population. However, the study on reliability of nasal bone length measurement was limited with contradictory results. This study aimed to investigate the reliability of fetal nasal bone length measurement at 11–14?weeks of gestation in the Thai population. Methods A total of 111 pregnant women at 11–14?weeks of gestation attending for the routine first-trimester ultrasound examination were recruited. Each case was measured separately by two examiners. Examiner 1 performed the first measurement in all cases; any of the other 5 examiners consecutively performed the second measurement. Three independent measurements were performed by each examiner and they were blinded to the results of the others. Intraobserver and interobserver variabilities were evaluated with the intraclass correlation coefficient (ICC). Results Nasal bone measurement was successfully performed in 106/111 cases (95.5%) by at least one examiner; 89 cases were performed by two examiners. The intraobserver variability was excellent for all examiners (ICC, 0.840-0.939). The interobserver variability between different pairs of examiners varied from moderate to excellent (ICC, 0.467-0.962). The interobserver variability between examiner 1 and any other examiner was good (ICC, 0.749). The Bland-Altman plot of the interobserver differences of nasal bone length measurements between examiner 1 and any other examiner showed good agreement. Conclusions The reliability of the fetal nasal bone length measurement at 11–14?weeks of gestation was good. The nasal bone length measurement was reproducible. Ethnicity has an effect on fetal nasal bone length, but reliability of nasal bone length measurement is critical to accuracy of screening and should be audited on an ongoing basis.

2013-01-01

66

FEL GAIN LENGTH AND TAPER MEASUREMENTS AT LCLS  

SciTech Connect

We present experimental studies of the gain length and saturation power level from 1.5 nm to 1.5 Angstroms at the Linac Coherent Light Source (LCLS). By disrupting theFEL process with an orbit kick, we are able to measure the X-ray intensity as a function of undulator length. This kick method is cross-checked with the method of removing undulator sections. We also study the FEL-induced electron energy loss after saturation to determine the optimal taper of the undulator K values. The experimental results are compared to theory and simulations.

Ratner, D.; Fawley, W. M.; Brachmann, A.; Decker, F.J.; Ding, Y.; Dowell, D.; Emma, P.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, P.; Huang, Z.; Loos, H.; Miahnahri, A.; Nuhn, H.D.; Turner, J.; Welch, J.; White, W.; Wu, J.; Xiang, D.; Yocky, G.; Fawley, W. M.

2009-08-14

67

How to Directly Measure a Kondo Cloud's Length  

NASA Astrophysics Data System (ADS)

We propose a method to directly measure, by electrical means, the Kondo screening cloud formed by an Anderson impurity coupled to semi-infinite quantum wires, on which an electrostatic gate voltage is applied at distance L from the impurity. We show that the Kondo cloud, and hence the Kondo temperature and the electron conductance through the impurity, are affected by the gate voltage, as L decreases below the Kondo cloud length. Based on this behavior, the cloud length can be experimentally identified by changing L with a keyboard type of gate voltage or tuning the coupling strength between the impurity and the wires.

Park, Jinhong; Lee, S.-S. B.; Oreg, Yuval; Sim, H.-S.

2013-06-01

68

Continuous time random walk with jump length correlated with waiting time  

NASA Astrophysics Data System (ADS)

A coupled continuous time random walk (CTRW) model is proposed, in which the jump length of a walker is correlated with waiting time. The power law distribution is chosen as the probability density function of waiting time and the Gaussian-like distribution as the probability density function of jump length. Normal diffusion, subdiffusion and superdiffusion can be realized within the present model. It is shown that the competition between long-tailed distribution and correlation of jump length and waiting time will lead to different diffusive behavior.

Liu, Jian; Bao, Jing-Dong

2013-02-01

69

Reducing trial length in force platform posturographic sleep deprivation measurements  

NASA Astrophysics Data System (ADS)

Sleepiness correlates with sleep-related accidents, but convenient tests for sleepiness monitoring are scarce. The posturographic test is a method to assess balance, and this paper describes one phase of the development of a posturographic sleepiness monitoring method. We investigated the relationship between trial length and accuracy of the posturographic time-awake (TA) estimate. Twenty-one healthy adults were kept awake for 32 h and their balance was recorded, 16 times with 30 s trials, as a function of TA. The balance was analysed with regards to fractal dimension, most common sway amplitude and time interval for open-loop stance control. While a 30 s trial allows estimating the TA of individual subjects with better than 5 h accuracy, repeating the analysis using shorter trial lengths showed that 18 s sufficed to achieve the targeted 5 h accuracy. Moreover, it was found that with increasing TA, the posturographic parameters estimated the subjects' TA more accurately.

Forsman, P.; Hæggström, E.; Wallin, A.

2007-09-01

70

Developing measurement concepts within context: Children's representations of length  

NASA Astrophysics Data System (ADS)

This article presents data gathered from an investigation which focused on the experiences children have with measurement in the early years of schooling. The focus of this article is children's understandings of length at this early stage. 32 children aged 4-6 years at an Australian primary school were asked to draw a ruler and describe their drawing, once in February at the beginning of school, and again in November towards the end of their first year of school. The drawings and their accompanying descriptions are classified within a matrix which, informed by Bronfenbrenner's ecological theory and literature regarding the development of length concepts, considers conceptual understanding and contextual richness. The responses revealed that children have a good understanding of length at the start of school, but that as their ability to contextualise develops so too does their conceptual understanding. This article suggests that participation in tasks such as these allows children to create their own understandings of length in meaningful ways. Additionally, the task and its matrix of analysis provide an assessment strategy for identifying children's understandings about length and the contexts in which these understandings develop.

MacDonald, Amy; Lowrie, Tom

2011-03-01

71

Electron Bunch Length Measurement for LCLS at SLAC  

SciTech Connect

At Stanford Linear Accelerator Center (SLAC) a Bunch Length Measurement system has been developed to measure the length of the electron bunch for its new Linac Coherent Light Source (LCLS). This destructive measurement uses a transverse-mounted RF deflector (TCAV) to vertically streak the electron beam and an image taken with an insertable screen and a camera. The device control software was implemented with the Experimental Physics and Industrial Control System (EPICS) toolkit. The analysis software was implemented in Matlab{trademark} using the EPICS/Channel Access Interface for Scilab{trademark} and Matlab{trademark} (labCA). This architecture allowed engineers and physicists to develop and integrate their control and analysis without duplication of effort.

Zelazny, M.; Allison, S.; Chevtsov, Sergei; Emma, P.; Kotturi, K.d.; Loos, H.; Peng, S.; Rogind, D.; Straumann, T.; /SLAC

2007-10-04

72

Length Scale Correlations of Cellular Microstructures in Directionally Solidified Binary System  

SciTech Connect

In a cellular array, a range of primary spacing is found to be stable under given growth conditions. Since a strong coupling of solute field exists between the neighboring cells, primary spacing variation should also influence other microstructure features such as cell shape and cell length. The existence of multiple solutions is examined in this study both theoretically as well as experimentally. A theoretical model is developed that identifies and relates four important microstructural lengths, which are found to be primary spacing, tip radius, cell width and cell length. This general microstructural relationship is shown to be valid for different cells in an array as well as for other cellular patterns obtained under different growth conditions. The unique feature of the model is that the microstructure correlation does not depend on composition or growth conditions since these variables scale microstructural lengths to satisfy the relationship obtained in this study. Detailed directional solidification experimental studies have been carried out in the succinonitrile-salol system to characterize and measure these four length scales. Besides the validation of the model, experimental results showed additional scaling laws to be present. In the regime where only a cellular structure is formed, the shape of the cell, the cell tip radius and the length of the cell are all found to scale individually with the local primary spacing. The presence of multiple solutions of primary spacing is also shown to influence the cell-dendrite transition that is controlled not only by the processing variables (growth velocity, thermal gradient and composition) but also by the local cell spacing. The cell-dendrite transition was found not to be sharp, but occurred over a range of processing conditions. Two critical conditions have been identified such that only cells are present below lower critics condition, and only dendrites are formed above the upper critics condition. Between these two limits, both cells and dendrites have been found to coexist. In this mixed regime, a critical local spacing is found above which a cell is unstable and forms a dendrite. An analytical expression is developed that relates the critical spacing for the cell-dendrite transition with processing conditions.

Yunxue Shen

2002-08-01

73

Length Scale Correlations of Cellular Microstructures in Directionally Solidified Binary System  

SciTech Connect

In a cellular array, a range of primary spacing is found to be stable under given growth conditions. Since a strong coupling of solute field exists between the neighboring cells, primary spacing variation should also influence other microstructure features such as cell shape and cell length. The existence of multiple solutions is examined in this study both theoretically as well as experimentally. A theoretical model is developed that identifies and relates four important microstructural lengths, which are found to be primary spacing, tip radius, cell width and cell length. This general microstructural relationship is shown to be valid for different cells in an array as well as for other cellular patterns obtained under different growth conditions. The unique feature of the model is that the microstructure correlation does not depend on composition or growth conditions since these variables scale microstructural lengths to satisfy the relationship obtained in this study. Detailed directional solidification experimental studies have been carried out in the succinonitrile-salol system to characterize and measure these four length scales. Besides the validation of the model, experimental results showed additional scaling laws to be present. In the regime where only a cellular structure is formed, the shape of the cell, the cell tip radius and the length of the cell are all found to scale individually with the local primary spacing. The presence of multiple solutions of primary spacing is also shown to influence the cell-dendrite transition that is controlled not only by the processing variables (growth velocity, thermal gradient and composition) but also by the local cell spacing. The cell-dendrite transition was found not to be sharp, but occurred over a range of processing conditions. Two critical conditions have been identified such that only cells are present below lower critics condition, and only dendrites are formed above the upper critics condition. Between these two limits, both cells and dendrites have been found to coexist. In this mixed regime, a critical local spacing is found above which a cell is unstable and forms a dendrite. An analytical expression is developed that relates the critical spacing for the cell-dendrite transition with processing conditions.

Yunxue Shen

2002-06-27

74

Correlation reflectometry for magnetic field and turbulence measurements  

NASA Astrophysics Data System (ADS)

The application of correlation reflectometry to local, internal magnetic field measurement in a magnetized plasma, as well as to the measurement of radial correlation lengths of electrostatic plasma turbulence is investigated. It is shown that when O- and X-mode reflectometer channels are cross-correlated, the cross- correlation is maximum at an X-mode frequency below the right hand cutoff, indicating unambiguously that the reflection originates spatially from in front of the cutoff layer. Given estimates of the density gradient scale length and turbulent k-spectral width, the X-mode frequency of maximum cross-correlation can be predicted by a one-dimensional full wave numerical code, under the conditions studied. Thus, the local magnetic field in the region of the cutoffs can be determined. In addition, direct comparisons between reflectometer and electrostatic probe measurements of turbulent correlation lengths are presented. Reflectometer and probes are found to be in good agreement. The conclusion is that, under the conditions studied, reflectometry is capable of accurate measurement of radial correlation lengths of electrostatic turbulence.

Gilmore, Mark Allen

1999-11-01

75

Reproduced Giant Localization Length of Two-Side Surface Disordered Nanowires with Long-Range Correlation  

NASA Astrophysics Data System (ADS)

We numerically investigate the normalized localization length of two-side rough nanowires as functions of energy, magnetic field and correlation strength by using modular recursive Green's function method. It is found that in the absence of correlation, while in the presence of magnetic field, the localization length increases linearly for two-side roughness, which is different to diverging exponentially for one-side roughness. Moreover, the localization of electrons is suppressed in the low energy region, but enhanced in the high energy region. In the presence of correlation, especially, an exponential enhancement in the localization length resumes in high energy region, in contrast to that in low energy region, the long-range correlations abnormally enhance the localization of electrons. A competitive mechanism is proposed to explain this behavior.

Zhao, Wei; Ding, Jian-Wen

2011-10-01

76

Influence of cross correlation step length on the surface stress of thin laser cladding Fe314 alloy coatings  

NASA Astrophysics Data System (ADS)

To measure the surface stress of thin laser cladding coatings with Rayleigh waves based on the cross correlation function, this paper introduced the influence of cross correlation step length on the stress measurement. Flat-shaped specimens made of laser cladding Fe314 alloy coatings were performed by static tensile tests, and Rayleigh wave signals were collected during the test process with an ultrasonic pulser and receiver instrument combined with two Rayleigh wave transducers. The difference in time of flight between two signals was determined based on the cross correlation function. The microstructure was observed by scanning electronic microscopy. The influence of the stress on the propagation velocity of Rayleigh waves and the relationship between the difference in time of flight and tensile stress under different cross correlation step lengths were analyzed. The inhomogeneous deformation of the coatings affects the relationship between the difference in time of flight and tensile stress; the stress measurement of the coatings is nearly constant with the increase of cross correlation step length when it attains one cycle.

Liu, Bin; Dong, Shi-yun; Xu, Bin-shi; He, Peng

2012-06-01

77

Equivalence and Accuracy of MOSFET Channel Length Measurement Techniques  

NASA Astrophysics Data System (ADS)

It is shown that the MOSFET channel length measurement techniques of Terada and Muta, Peng et al., Whitfield, Suciu and Johnston, and De La Moneda et al. are actually equivalent, i.e. merely different expressions of the same formula for channel length in terms of measured resistance, and that some of the transresistance methods of Jain, although not equivalent, are also related to the same formula. The accuracy of this formula is evaluated for the general case and related to the error components due to source and drain resistance asymmetry, short channel geometry effect, and variation of series resistance with bias. No independent error component due to field-induced mobility degradation is found. Finally the errors in the methods of Terada and Muta, Chen et al., Sheu et al., Wordeman et al. and Jain, are determined and compared. The gate transresistance technique is found to be the most accurate method.

Jain, Sanjay

1989-02-01

78

Absolute bunch length measurements by incoherent radiation fluctuation analysis  

SciTech Connect

By analyzing the pulse to pulse intensity fluctuations of the radiation emitted by a charge particle in the incoherent part of the spectrum, it is possible to extract information about the spatial distribution of the beam. At the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory, we have developed and successfully tested a simple scheme based on this principle that allows for the absolute measurement of the rms bunch length. A description of the method and the experimental results are presented.

Sannibale, Fernando; Stupakov, Gennady; Zolotorev, Max; Filippetto, Daniele; Jagerhofer, Lukas

2008-09-29

79

Absolute Bunch Length Measurements by Incoherent Radiation Fluctuation Analysis  

SciTech Connect

By analyzing the pulse to pulse intensity fluctuations of the radiation emitted by a charge particle in the incoherent part of the spectrum, it is possible to extract information about the spatial distribution of the beam. At the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory, we have developed and successfully tested a simple scheme based on this principle that allows for the absolute measurement of the rms bunch length. A description of the method and the experimental results are presented.

Sannibale, F.; /LBL, Berkeley; Stupakov, G.V.; /SLAC; Zolotorev, M.S.; /LBL, Berkeley; Filippetto, D.; /INFN, Rome; Jagerhofer, L.; /Vienna, Tech. U.

2009-12-09

80

Daily energy expenditure of male barn swallows correlates with tail-streamer length: handicap-mediated foraging strategies.  

PubMed Central

Daily energy expenditure (DEE) of male barn swallows (Hirundo rustica), measured using the doubly labelled water technique, correlated with streamer length. Contrary to predictions derived from previous findings, neither a positive linear nor a u-shaped relationship was found between DEE and streamer length. Instead, an n-shaped curve showed that the highest DEE corresponded to an intermediate streamer length of 119 mm. A model incorporating estimates of resting metabolism and flight energy expenditure from aerodynamics models suggested that variation in individual tail dynamics was the most likely explanation for the observed DEE. We suggest that streamer length is coupled to foraging strategy, because tail dynamics control flight performance, which in turn influences flight behaviour.

Nudds, Robert L; Spencer, Karen A

2004-01-01

81

Direct Measurement of the Formation Length of Photons  

NASA Astrophysics Data System (ADS)

We report the first observation of a shoulder in the radiation spectrum from GeV electrons in a structured target consisting of two thin and closely spaced foils. The position of the shoulder depends on the target spacing and is directly connected to the finite formation length of a low-energy photon emitted by an ultrarelativistic electron. With the present setup it is possible to control the separation of the foils on a ?m scale and hence measure interference effects caused by the macroscopic dimensions of the formation length. Several theoretical groups have predicted this effect using different methods. Our observations have a preference for the modified theory by Blankenbecler but disagree with the results of Baier and Katkov.

Andersen, Kristoffer K.; Andersen, Søren L.; Esberg, Jakob; Knudsen, Helge; Mikkelsen, Rune; Uggerhøj, Ulrik I.; Sona, Pietro; Mangiarotti, Alessio; Ketel, Tjeerd J.; Ballestrero, Sergio

2012-02-01

82

Dynamic correlation length growth in superspin glass: Bridging experiments and simulations  

NASA Astrophysics Data System (ADS)

Interacting magnetic nanoparticles display a wide variety of magnetic behaviors that are now being gathered in the emerging field of ``supermagnetism.'' We have investigated how the out-of-equilibrium dynamics in the disordered superspin glass (SSG) state of a frozen ferrofluid sample is affected by texturation. Via magnetization relaxation experiments at low temperatures, we were able to estimate superspin correlation lengths for both textured and non-textured samples. The comparison with simulations and experiments on atomic spin glasses shows that the dynamic correlations in SSG's appear to develop in a way reminiscent to those in atomic spin glasses at intermediate time/length scales.

Nakamae, S.; Crauste-Thibierge, C.; L'Hôte, D.; Vincent, E.; Dubois, E.; Dupuis, V.; Perzynski, R.

2012-12-01

83

Granular force on objects and correlation length: Drag coefficient enhancement in low Froude number flow regimes  

NASA Astrophysics Data System (ADS)

Both laboratory tests and discrete numerical simulations related to the drag experienced by various objects inside granular flows showed a large increase in drag coefficient when the Froude number of the undisturbed incident flow decreased. The present paper describes an elementary theory that can catch this observed trend. Accounting for a correlation length related to the presence of the obstacle, it is possible to derive a generalized drag coefficient. The careful calibration of the model on existing data about dry and cohesive dense granular flows around obstacles gives crucial information on the correlation length.

Faug, Thierry

2013-06-01

84

The correlation length of the liquid-liquid mixture perfluoroheptane and 2,2,4-trimethylpentane  

NASA Astrophysics Data System (ADS)

The turbidity of the liquid-liquid mixture perfluoroheptane and 2,2,4-trimethylpentane (also known as iso-octane) has been measured and used to determine the correlation length amplitude ?_0. By measuring the ratio of the transmitted to incident light intensities over three decades in reduced temperature, we are able to determine that ?0 = 0.242 ± 0.009 nm. This value differs significantly from that reported in the literature. The earlier literature value for ?_0, when combined with the amplitude A^+ determined in a recent heat capacity measurement on this system, produced the two-scale-factor universality constant X = (A^+?_0^3)/kB = 0.009 ± 0.002, which was not consistent with other experiments and theories that had found a value between 0.018 and 0.020. However, when we combine our value of ?0 with the amplitude A^+, the two-scale-factor universality constant X = 0.0177 ± 0.0018, which is quite consistent with other determinations.

Braganza, Clinton I.; Jacobs, D. T.

2002-03-01

85

Axial length measurement techniques in pediatric eyes with cataract.  

PubMed

Globe axial length (AL) in children is commonly measured using either contact or immersion technique. Office measurement of AL can be difficult in young children and infants and must often be done under anesthesia in an eye that is unable to cooperate with precise fixation and centration. Contact A-scan measurements yield shorter AL, on average, than immersion A-scan measurements in pediatric eyes. This difference is mainly the result of the anterior chamber depth rather than the lens thickness value. During intraocular lens power calculation, if globe axial length is measured by the contact technique, it will result in the use of an average 1-D stronger IOL power than is actually required. This can lead to induced myopia in the postoperative refraction. In our studied patients, there was a significant difference in prediction error between contact A-scan biometry and immersion A-scan biometry. The immersion A-scan technique is recommended for pediatric IOL power calculation. We also provide a review of biometry in pediatric eyes. The overall mean AL of pediatric cataractous eyes is significantly different than the mean AL of non cataractous eyes. More importantly, the standard deviation is higher in eyes with cataract than in those without. Three phases of eye growth in children have been documented: A rapid, postnatal phase from birth to 6 months of age, followed by a slower, infantile phase from 6 to 18 months of age, and finally a slow, juvenile phase from 18 months forward. In our study, girls had shorter ALs than boys and African-American subjects had longer ALs than Caucasians. Eyes with unilateral cataract had shorter ALs than eyes with bilateral cataract during the earlier years, but had longer ALs during later childhood. PMID:23960963

Wilson, M Edward; Trivedi, Rupal H

2012-01-01

86

A Note on the Critical Enhancement of Transport Properties and Correlation Length of Fluids  

NASA Astrophysics Data System (ADS)

The thermal conductivity and viscosity of fluids are known to exhibit an enhancement due to critical fluctuations. Procedures proposed in the literature for estimating the correlation length determining the magnitude of these enhancements have been reviewed, and a recommendation to reduce complexity and computation time is presented.

Perkins, R. A.; Sengers, J. V.

2013-10-01

87

Radial distribution of turbulence correlation lengths obtained by reflectometry in the TJ-I tokamak (abstract)  

Microsoft Academic Search

A method for determination of radial correlation lengths of the electrostatic turbulence has been developed and applied to the TJ-I tokamak [T. Estrada, J. Sanchez, B. Bran˜as, and A. P. Navarro, Rev. Sci. Instrum. 61, 3034 (1990)]. The method uses homodyne detection and is based on the slow sweeping of one oscillator while the other remains at fixed frequency. The

J. Sanchez; E. de la Luna; T. Estrada

1992-01-01

88

The use of short coherence length laser light for eye length measurement  

Microsoft Academic Search

There is a need for an accurate knowledge of the length of the eye, for example for improved precision in the design and manufacture of optical lens implants and other opthalmic surgical procedures. The parameter itself is not readily determined, and the primary method in use at the moment in ultrasonography, which gives a direct estimate of the eye length.

D. N. Wang; G. Dick; S. Chen; K. T. V. Grattan; A. W. Palmer

1992-01-01

89

Thin-filament length correlates with fiber type in human skeletal muscle  

PubMed Central

Force production in skeletal muscle is proportional to the amount of overlap between the thin and thick filaments, which, in turn, depends on their lengths. Both thin- and thick-filament lengths are precisely regulated and uniform within a myofibril. While thick-filament lengths are essentially constant across muscles and species (?1.65 ?m), thin-filament lengths are highly variable both across species and across muscles of a single species. Here, we used a high-resolution immunofluorescence and image analysis technique (distributed deconvolution) to directly test the hypothesis that thin-filament lengths vary across human muscles. Using deltoid and pectoralis major muscle biopsies, we identified thin-filament lengths that ranged from 1.19 ± 0.08 to 1.37 ± 0.04 ?m, based on tropomodulin localization with respect to the Z-line. Tropomodulin localized from 0.28 to 0.47 ?m further from the Z-line than the NH2-terminus of nebulin in the various biopsies, indicating that human thin filaments have nebulin-free, pointed-end extensions that comprise up to 34% of total thin-filament length. Furthermore, thin-filament length was negatively correlated with the percentage of type 2X myosin heavy chain within the biopsy and shorter in type 2X myosin heavy chain-positive fibers, establishing the existence of a relationship between thin-filament lengths and fiber types in human muscle. Together, these data challenge the widely held assumption that human thin-filament lengths are constant. Our results also have broad relevance to musculoskeletal modeling, surgical reattachment of muscles, and orthopedic rehabilitation.

Gokhin, David S.; Kim, Nancy E.; Lewis, Sarah A.; Hoenecke, Heinz R.; D'Lima, Darryl D.

2012-01-01

90

Range of interaction between DNA-bending proteins is controlled by the second-longest correlation length for bending fluctuations.  

PubMed

When a DNA molecule is stretched, the zero-force correlation length for its bending fluctuations-the persistence length A-bifurcates into two different correlation lengths-the shorter "longitudinal" correlation length ?_{?}(f) and the longer "transverse" correlation length ?_{?}(f). In the high-force limit, ?_{?}(f)=?_{?}(f)/2=sqrt[k_{B}TA/f]/2. When DNA-bending proteins bind to the DNA molecule, there is an effective interaction between the protein-generated bends mediated by DNA elasticity and bending fluctuations. Surprisingly, the range of this interaction is not the longest correlation length associated with transverse fluctuations of the tangent vector along the polymer, but instead is the second longest longitudinal correlation length ?_{?}(f,?). The effect arises from the protein-bend contribution to the Hamiltonian having an axial rotational symmetry which eliminates its coupling to the transverse fluctuations. PMID:23368394

Zhang, Houyin; Marko, John F

2012-12-10

91

Performance measures for correlation filters  

SciTech Connect

Several performance criteria are described to enable a fair comparison among the various correlation filter designs: signal-to-noise ratio, peak sharpness, peak location, light efficiency, discriminability, and distortion invariance. The trade-offs resulting between some of these criteria are illustrated with the help of a new family of filters called fractional power filters (FPFs). The classical matched filter, phase-only filter (POF), and inverse filter are special cases of FPFs. Using examples, we show that the POF appears to provide a good compromise between noise tolerance and peak sharpness. Keywords: Correlators, performance criteria, matched filters, phase-only filters, fractional power filters.

Vijaya Kumar, B.V.K.; Hassebrook, L. (Carnegie Mellon University, Department of Electrical Computer Engineering, Center for Excellence in Optical Data Processing, Pittsburgh, PA (USA))

1990-07-10

92

Resolution of Fluorescence Correlation Measurements  

Microsoft Academic Search

The resolution limit of fluorescence correlation spectroscopy for two-component solutions is investigated theoretically and experimentally. The autocorrelation function for two different particles in solution were computed, statistical noise was added, and the resulting curve was fitted with a least squares fit. These simulations show that the ability to distinguish between two different molecular species in solution depends strongly on the

Ulrich Meseth; Thorsten Wohland; Rudolf Rigler; Horst Vogel

1999-01-01

93

Measurement of spin memory lengths in PdNi and PdFe ferromagnetic alloys  

NASA Astrophysics Data System (ADS)

Weakly ferromagnetic alloys are being used by several groups in the study of superconducting/ferromagnetic hybrid systems. Because spin-flip and spin-orbit scattering in such alloys disrupt the penetration of pair correlations into the ferromagnetic material, it is desirable to have a direct measurement of the spin memory length in such alloys. We have measured the spin memory length at 4.2 K in sputtered Pd0.88Ni0.12 and Pd0.987Fe0.013 alloys using methods based on current-perpendicular-to-plane giant magnetoresistance. The alloys are incorporated into hybrid spin valves of various types, and the spin memory length is determined by fits of the Valet-Fert spin-transport equations to data of magnetoresistance vs alloy thickness. For the case of PdNi alloy, the resulting values of the spin memory length are lsfPdNi=2.8±0.5nm and 5.4±0.6nm , depending on whether or not the PdNi is exchange biased by an adjacent Permalloy layer. For PdFe, the spin memory length is somewhat longer, lsfPdFe=9.6±2nm , consistent with earlier measurements indicating lower spin-orbit scattering in that material. Unfortunately, even the longer spin memory length in PdFe may not be long enough to facilitate observation of spin-triplet superconducting correlations predicted to occur in superconducting/ferromagnetic hybrid systems in the presence of magnetic inhomogeneity.

Arham, H. Z.; Khaire, Trupti S.; Loloee, R.; Pratt, W. P., Jr.; Birge, Norman O.

2009-11-01

94

Correlation of ion dynamics with characteristic length scales and network structural units in bismuth borate glasses  

NASA Astrophysics Data System (ADS)

Ion dynamics in lithium bismuth borate conducting glasses have been reported in wide composition and temperature ranges. The activation energy for the dc conduction has been analysed using Anderson-Stuart model and a correlation between the dc conductivity and the doorway radius has been predicted. The characteristic length scales for ion dynamics, such as mean square displacement and spatial extent of sub-diffusive motion of lithium ions have been determined from the ac conductivity and dielectric spectra, respectively. A direct connection between the ion dynamics and the characteristic length scales and the network structural units have been established.

Shaw, A.; Ghosh, A.

2013-09-01

95

Correlation of ion dynamics with characteristic length scales and network structural units in bismuth borate glasses.  

PubMed

Ion dynamics in lithium bismuth borate conducting glasses have been reported in wide composition and temperature ranges. The activation energy for the dc conduction has been analysed using Anderson-Stuart model and a correlation between the dc conductivity and the doorway radius has been predicted. The characteristic length scales for ion dynamics, such as mean square displacement and spatial extent of sub-diffusive motion of lithium ions have been determined from the ac conductivity and dielectric spectra, respectively. A direct connection between the ion dynamics and the characteristic length scales and the network structural units have been established. PMID:24070293

Shaw, A; Ghosh, A

2013-09-21

96

Growing Point-to-Set Length Scale Correlates with Growing Relaxation Times in Model Supercooled Liquids  

NASA Astrophysics Data System (ADS)

It has been demonstrated recently that supercooled liquids sharing simple structural features (e.g. pair distribution functions) may exhibit strikingly distinct dynamical behavior. Here we show that a more subtle structural feature correlates with relaxation times in three simulated systems that have nearly identical radial distribution functions but starkly different dynamical behavior. In particular, for the first time we determine the thermodynamic “point-to-set” length scale in several canonical model systems and demonstrate the quantitative connection between this length scale and the growth of relaxation times. Our results provide clues necessary for distinguishing competing theories of the glass transition.

Hocky, Glen M.; Markland, Thomas E.; Reichman, David R.

2012-06-01

97

Measuring and modeling thermal fluctuations at nanometer length scales  

NASA Astrophysics Data System (ADS)

The size of mechanical, electrical, and optical devices continues to be reduced. As the length scales of such devices decrease, coupling to the external environment greatly increases. Thermal fluctuations due to momentum exchange between air molecules and micron scale devices under ambient conditions can effect the dynamics of a system. To illustrate this we use an atomic force microscope cantilever and detection system to measure background noise and thermal fluctuations of a micron size beam. The beam is modeled by a Langevin-type equation that is externally forced by a white-noise spectrum having an analytic as opposed to a statistical form. This model is compared with experimental data. It is found that at higher frequencies, a white-noise spectrum is not sufficient to model such a system. We modify the forcing spectrum so that it decays at higher frequencies and subsequently achieve closer agreement between the model and the experimental observations.

Ralich, R. M.; Ramsier, R. D.; Quinn, D. D.; Clemons, C. B.; Young, G. W.

2002-05-01

98

Total diesel exhaust particulate length measurements using a modified household smoke alarm ionization chamber.  

PubMed

To evaluate the effectiveness of various means to combat the negative health effects of ultrafine particles emitted by internal combustion engines, a reliable, low-cost instrument for dynamic measurements of the exhaust emissions of ultrafine particulate matter (PM) is needed. In this study, an ordinary ionization-type building smoke detector was modified to serve as a measuring ionization chamber and utilized for dynamic measurements of PM emissions from diesel engines. When used with diluted exhaust, the readings show an excellent correlation with total particulate length. The instrument worked well with raw and diluted exhaust and with varying emission levels and is well suitable for on-board use. PMID:21387930

Vojtisek-Lom, Michal

2011-02-01

99

Decoherence and measurement-induced correlations  

SciTech Connect

Decoherence arises from the interaction of a quantum system with the environment or, more precisely, from the measurement in which the environment ''measures'' the quantum system and establishes correlations with it. In this work, we first quantify measurement-induced correlations from both classical and quantum perspectives. Then we quantify decoherence via measurement-induced classical correlations. By virtue of an intrinsic and powerful link between entanglement (as quantified by entanglement of formation) and classical correlations (as quantified by the difference between the total correlations and quantum discord) in pure tripartite systems, we present general analytical formulas for measurement-induced correlations and decoherence measures for qubit systems and, furthermore, reveal a conservation relation for the information-disturbance tradeoff.

Luo Shunlong; Li Nan [Academy of Mathematics and Systems Science, Chinese Academy of Sciences, 100190 Beijing (China)

2011-11-15

100

The Association of Visit Length and Measures of Patient-Centered Communication in HIV Care  

PubMed Central

Introduction Patient centered clinical communication may be associated with longer encounters. Methods We used the General Medical Interaction Analysis System (GMIAS) to code transcripts of routine outpatient visits in HIV care, and create 5 measures of patient-centeredness. We defined visit length as number of utterances. To better understand properties of encounters reflected in these measures, we conducted a qualitative analysis of the 15 longest and 15 shortest visits. Results All 5 measures were significantly associated with visit length (P<.05, rank order correlations .21 to .44). In multivariate regressions, association of patient centeredness with visit length was attenuated for 4 measures, and increased for 1; two were no longer statistically significant (p>0.05). Black and Hispanic race were associated with shorter visits compared with white race. Some of the longest visits featured content that could be considered extraneous to appropriate care. Conclusion Patient centeredness is weakly related to visit length, but may reflect inefficient use of time in long encounters. Practice Implications Efforts to make visits more patient centered should focus on improving dialogue quality and efficient use of time, not on making visits longer. Shorter visits for Black and Hispanic patients could contribute to health disparities related to race and ethnicity.

Epstein, Lauren; Lee, Yoojin; Rogers, William; Beach, Mary Catherine; Wilson, Ira B.

2011-01-01

101

Effects of finite initial correlation length on scattering structure functions of quenched systems  

NASA Astrophysics Data System (ADS)

We examined the effects of a large initial correlation length on the scattering structure function (SSF) when the order parameter is not conserved, using the approach developed by Ohta, Jasnow and Kawasaki. In particular, the SSF exhibits the usual scaling behaviour except that the scaling functions now contain an additional time-dependent parameter. The new scaling functions are computed for various values of the parameter in two and three dimensions.

Ohta, S.; Ohta, T.; Kawasaki, K.; Sekimoto, K.

1985-12-01

102

Postulates for measures of genuine multipartite correlations  

SciTech Connect

A lot of research has been done on multipartite correlations, but the problem of satisfactorily defining genuine multipartite correlations--those not trivially reducible to lower partite correlations--remains unsolved. In this paper we propose three reasonable postulates which each measure or indicator of genuine multipartite correlations (or genuine multipartite entanglement) should satisfy. We also introduce the concept of degree of correlations, which gives partial characterization of multipartite correlations. Then, we show that covariance does not satisfy two postulates and hence it cannot be used as an indicator of genuine multipartite correlations. Finally, we propose a candidate for a measure of genuine multipartite correlations based on the work that can be drawn from a local heat bath by means of a multipartite state.

Bennett, Charles H. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Grudka, Andrzej [Institute of Theoretical Physics and Astrophysics, University of Gdansk, PL-80-952 Gdansk (Poland); Faculty of Physics, Adam Mickiewicz University, PL-61-614 Poznan (Poland); Horodecki, Michal; Horodecki, Ryszard [Institute of Theoretical Physics and Astrophysics, University of Gdansk, PL-80-952 Gdansk (Poland); Horodecki, Pawel [Faculty of Applied Physics and Mathematics, Technical University of Gdansk, PL-80-952 Gdansk (Poland)

2011-01-15

103

Robustness versus efficiency for nonparametric correlation measures  

Microsoft Academic Search

Nonparametric correlation measures at the Kendall and Spearman correlation are widely used in the behavioral sciences. These measures are often said to be robust, in the sense of being resistant to outlying observations. In this note we formally study their robustness by means of their influence functions. Since robustness of an estimator often comes at the price of a loss

Christophe Croux; Catherine Dehon

2008-01-01

104

Robustness versus eciency for nonparametric correlation measures  

Microsoft Academic Search

Nonparametric correlation measures at the Kendall and Spearman correlation are widely used in the behavioral sciences. These measures are often said to be robust, in the sense of being resistant to outlying observations. In this note we for- mally study their robustness by means of their inuence functions. Since robustness of an estimator often comes at the price of a

Christophe Croux; Catherine Dehon

105

Robustness versus Efficiency for Nonparametric Correlation Measures  

Microsoft Academic Search

Nonparametric correlation measures at the Kendall and Spearman correlation are widely used in the behavioral sciences. These measures are often said to be robust, in the sense of being resistant to outlying observations. In this note we formally study their robustness by means of their infuence functions. Since robustness of an estimator often comes at the price of a loss

Christophe Croux; Catherine Dehon

2008-01-01

106

Water absorption length measurement with the ANTARES optical beacon system  

NASA Astrophysics Data System (ADS)

ANTARES is a neutrino telescope located in the Mediterranean Sea with the aim of detecting high energy neutrinos of extra-terrestrial origin. It consists of a three dimensional array on 12 detection lines of photomultiplier tubes (PMTs) able to detect the Cherenkov light induced by muons produced in the interaction of neutrinos with the surrounding water and seabed. To reach the best angular resolution, good time and positioning calibrations are required. The propagation of Cherenkov photons strongly depends on the optical properties of the sea water, which has an impact on the reconstruction efficiency. The determination of the optical parameters, as the absorption and scattering lengths, is crucial to calculate properly the effective area and the angular resolution of the detector. The ANTARES optical beacon system consists of pulsed and fast, well controlled light sources distributed throughout the detector to carry out in situ the relative time calibration of the detector components. In this contribution we show some results on the sea water optical properties and their stability measured with the optical beacon system.

Yepes-Ramirez, Harold; ANTARES Collaboration

2011-01-01

107

Commuting quantum transfer-matrix approach to intrinsic fermion system: Correlation length of a spinless fermion model  

Microsoft Academic Search

The quantum transfer-matrix approach to integrable lattice fermion systems is presented. As a simple case we treat the spinless fermion model with repulsive interaction in critical regime. We derive a set of nonlinear integral equations which characterize the free energy and the correlation length of for an arbitrary particle density at any finite temperatures. The correlation length is determined

Kazumitsu Sakai; Masahiro Shiroishi; Junji Suzuki; Yukiko Umeno

1999-01-01

108

Zeros of the dispersion relation of the elementary excitation and the correlation length of strongly correlated quantum systems  

NASA Astrophysics Data System (ADS)

We argue that the imaginary part of a zero of the dispersion relation of the elementary excitation of quantum systems is equal to the inverse correlation length. We confirm the relation for the Hubbard model[1] in the half-filled case; it has been confirmed only for the S=1/2 antiferromagnetic XXZ chain[2]. In order to search zeros of the dispersion relation in the complex momentum space efficiently, we introduce a non-Hermitian generalization of quantum systems by adding an imaginary vector potential ig to the momentum operator[3]. We also show for the half-filled Hubbard model the reason why the non-Hermitian critical point[4] is equal to the inverse correlation length[5] by noting the dispersion relation of the charge excitation. [1] Y. Nakamura and N. Hatano, in preparation. [2] K. Okunishi, Y. Akutsu, N. Akutsu and T. Yamamoto, Phys. Rev. B 64 (2001) 104432. [3] Y. Nakamura and N. Hatano, Physica B 378-380 (2006) 292; J. Phys. Soc. Jpn. 75 (2006) 114001. [4] T. Fukui and N. Kawakami, Phys. Rev. B 58 (1998) 16051. [5] C. A. Stafford and A. J. Millis, Phys. Rev. B 48 (1993) 1409.

Nakamura, Yuichi

2007-03-01

109

Correlation measurements with on-off detectors  

NASA Astrophysics Data System (ADS)

We present a general method to detect nonclassical radiation fields with systems of on-off detectors. We especially study higher order correlations for the identification of nonclassical radiation. This allows us to directly characterize quantum correlations by the statistics measured with systems of on-off detectors. Additionally, we generalize our method to multiple detector systems for measurements of correlations between light fields. We also consider multimode radiation fields and isolate nonclassicality in terms of the space time correlations. Finally, we present results for the quantum statistics using on-off detectors operating in nonlinear detection modes.

Sperling, J.; Vogel, W.; Agarwal, G. S.

2013-10-01

110

Transfer-matrix scaling from disorder-averaged correlation lengths for diluted Ising systems  

NASA Astrophysics Data System (ADS)

A transfer-matrix-scaling technique is developed for randomly diluted systems, and applied to the site-diluted Ising model on a square lattice in two dimensions. For each allowed disorder configuration between two adjacent columns, the contribution of the respective transfer matrix to the decay of correlations is considered only as far as the ratio of its two largest eigenvalues, allowing an economical calculation of a configuration-averaged correlation length. Standard phenomenological-renormalization procedures are then used to analyze aspects of the phase boundary which are difficult to assess accurately by alternative methods. For magnetic site concentration p close to pc, the extent of exponential behavior of the Tc×p curve is clearly seen for over two decades of variation of p-pc. Close to the pure-system limit, the exactly known reduced slope is reproduced to a very good approximation, though with nonmonotonic convergence. The averaged correlation lengths are inserted into the exponent-amplitude relationship predicted by conformal invariance to hold at criticality. The resulting exponent ? remains near the pure value (1/4) for all intermediate concentrations until it crosses over to the percolation value at the threshold.

de Queiroz, S. L. A.; Stinchcombe, R. B.

1994-10-01

111

Significant Correlation of Species Longevity with DNA Double Strand Break-Recognition but not with Telomere Length  

PubMed Central

Summary The identification of the cellular mechanisms responsible for the wide differences in species lifespan remains one of the major unsolved problems of the biology of aging. We measured the capacity of nuclear protein to recognize DNA double strand breaks (DSB) and telomere length of skin fibroblasts derived from mammalian species that exhibit wide differences in longevity. Our results indicate DNA DSB recognition increases exponentially with longevity. Further, an analysis of the level of Ku80 protein in human, cow, and mouse suggests that Ku levels vary dramatically between species and these levels are strongly correlated with longevity. In contrast mean telomere length appears to decrease with increasing longevity of the species, although not significantly. These findings suggest that an enhanced ability to bind to DNA-ends may be important for longevity. A number of possible roles for increased levels of Ku and DNA-PKcs are discussed.

Lorenzini, Antonello; Johnson, F. Brad; Oliver, Anthony; Tresini, Maria; Smith, Jasmine S.; Hdeib, Mona; Sell, Christian; Cristofalo, Vincent J.; Stamato, Thomas D.

2009-01-01

112

Norm-based measurement of quantum correlation  

SciTech Connect

In this paper we derived a necessary and sufficient condition for classical correlated states and proposed a norm-based measurement Q of quantum correlation. Using the max norm of operators, we gave the expression of the quantum correlation measurement Q and investigated the dynamics of Q in Markovian and non-Markovian cases, respectively. Q decays exponentially and vanishes only asymptotically in the Markovian case and causes periodical death and rebirth in the non-Markovian case. In the pure state, the quantum correlation Q is always larger than the entanglement, which was different from other known measurements. In addition, we showed that locally broadcastable and broadcastable are equivalent and reproved the density of quantum correlated states.

Wu Yuchun; Guo Guangcan [Key Laboratory of Quantum Information, University of Science and Technology of China, 230026 Hefei (China)

2011-06-15

113

Criteria for measures of quantum correlations  

Microsoft Academic Search

Entanglement does not describe all quantum correlations and several authors have shown the need to go beyond entanglement when dealing with mixed states. Several different measures have sprung up in the literature, for a variety of reasons, To describe quantum correlations; some are known under the collective name quantum discord. Yet, in the same sprit as the criteria for entanglement

Aharon Brodutch; Kavan Modi

2011-01-01

114

Growth of a dynamical correlation length in an aging superspin glass  

NASA Astrophysics Data System (ADS)

We report on zero-field-cooled magnetization relaxation experiments on a concentrated frozen ferrofluid exhibiting a low-temperature superspin glass transition. With a method initially developed for spin glasses, we investigate the field dependence of the relaxations that take place after different aging times. We extract the typical number of correlated spins involved in the aging dynamics. This brings important insights into the dynamical correlation length and its time growth. Our results, consistent with expressions obtained for spin glasses, extend the generality of these behaviours to the class of superspin glasses. Since the typical flipping time is much larger for superspins than for atomic spins, our experiments probe a time regime much closer to that of numerical simulations.

Wandersman, E.; Dupuis, V.; Dubois, E.; Perzynski, R.; Nakamae, S.; Vincent, E.

2008-11-01

115

Measurements of attenuation and absorption lengths with the KASCADE experiment  

NASA Astrophysics Data System (ADS)

The attenuation of the electron shower size beyond the shower maximum is studied with the KASCADE extensive air shower (EAS) experiment in the primary energy range of about 1014-1016 eV. Attenuation and absorption lengths are determined by applying different approaches, including the method of constant intensity, the decrease of the flux of EASs with increasing zenith angle, and its variation with ground pressure. We observe a significant dependence of the results on the applied method. The determined values of the attenuation length ranges from 175 to 196 g/cm2 and of the absorption length from 100 to 120 g/cm2. The origin of these differences is discussed emphasizing the influence of intrinsic shower fluctuations.

KASCADE Collaboration; Antoni, T.; Apel, W. D.; Badea, A. F.; Bekk, K.; Bercuci, A.; Blümer, H.; Bozdog, H.; Brancus, I. M.; Büttner, C.; Chilingarian, A.; Daumiller, K.; Doll, P.; Engel, R.; Engler, J.; Feßler, F.; Gils, H. J.; Glasstetter, R.; Haeusler, R.; Haungs, A.; Heck, D.; Hörandel, J. R.; Iwan, A.; Kampert, K.-H.; Klages, H. O.; Maier, G.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Müller, M.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Petcu, M.; Rebel, H.; Risse, M.; Roth, M.; Schatz, G.; Schieler, H.; Scholz, J.; Thouw, T.; Ulrich, H.; Vardanyan, A.; Weber, J. H.; Weindl, A.; Wentz, J.; Wochele, J.; Zabierowski, J.

2003-09-01

116

Topological phases and topological entropy of two-dimensional systems with finite correlation length  

SciTech Connect

We elucidate the topological features of the entanglement entropy of a region in two-dimensional quantum systems in a topological phase with a finite correlation length {xi}. First, we suggest that simpler reduced quantities, related to the von Neumann entropy, could be defined to compute the topological entropy. We use our methods to compute the entanglement entropy for the ground-state wave function of a quantum eight-vertex model in its topological phase and show that a finite correlation length adds corrections of the same order as the topological entropy which come from sharp features of the boundary of the region under study. We also calculate the topological entropy for the ground state of the quantum dimer model on a triangular lattice by using a mapping to a loop model. The topological entropy of the state is determined by loop configurations with a nontrivial winding number around the region under study. Finally, we consider extensions of the Kitaev wave function, which incorporate the effects of electric and magnetic charge fluctuations, and use it to investigate the stability of the topological phase by calculating the topological entropy.

Papanikolaou, Stefanos; Fradkin, Eduardo [Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green St., Urbana, Illinois 61801-3080 (United States); Raman, Kumar S. [Department of Physics and Astronomy, University of California at Riverside, Riverside, California 92521 (United States)

2007-12-01

117

Line Tensions, Correlation Lengths, and Critical Exponents in Lipid Membranes Near Critical Points  

PubMed Central

Membranes containing a wide variety of ternary mixtures of high chain-melting temperature lipids, low chain-melting temperature lipids, and cholesterol undergo lateral phase separation into coexisting liquid phases at a miscibility transition. When membranes are prepared from a ternary lipid mixture at a critical composition, they pass through a miscibility critical point at the transition temperature. Since the critical temperature is typically on the order of room temperature, membranes provide an unusual opportunity in which to perform a quantitative study of biophysical systems that exhibit critical phenomena in the two-dimensional Ising universality class. As a critical point is approached from either high or low temperature, the scale of fluctuations in lipid composition, set by the correlation length, diverges. In addition, as a critical point is approached from low temperature, the line tension between coexisting phases decreases to zero. Here we quantitatively evaluate the temperature dependence of line tension between liquid domains and of fluctuation correlation lengths in lipid membranes to extract a critical exponent, ?. We obtain ? = 1.2 ± 0.2, consistent with the Ising model prediction ? = 1. We also evaluate the probability distributions of pixel intensities in fluorescence images of membranes. From the temperature dependence of these distributions above the critical temperature, we extract an independent critical exponent of ? = 0.124 ± 0.03, which is consistent with the Ising prediction of ? = 1/8.

Honerkamp-Smith, Aurelia R.; Cicuta, Pietro; Collins, Marcus D.; Veatch, Sarah L.; den Nijs, Marcel; Schick, M.; Keller, Sarah L.

2008-01-01

118

Bunch length measurements at the TESLA Test Facility using a streak camera  

Microsoft Academic Search

A streak camera provides a direct and convenient way to measure bunch lengths in the millimeter and submillimeter range. At the TESLA Test Facility (TTF) a streak camera with a subpicosecond resolution is in operation. A bunch compressor is used to produce bunch lengths down to 250 ?m for the operation of the TTF free electron laser. Bunch length measurements

K. Honkavaara; P. Piot; S. Schreiber; D. Sertore

2001-01-01

119

Relationships between otoacoustic emissions and a proxy measure of cochlear length derived from the auditory brainstem response  

PubMed Central

Brief tones of 1.0 and 8.0 kHz were used to evoke auditory brainstem responses (ABRs), and the differences between the wave-V latencies for those two frequencies were used as a proxy for cochlear length. The tone bursts (8 ms in duration including 2-ms rise/fall times, and 82 dB in level) were, or were not, accompanied by a continuous, moderately intense noise band, highpass filtered immediately above the tone. The proxy values for length were compared with various measures of otoacoustic emissions (OAEs) obtained from the same ears. All the correlations were low, suggesting that cochlear length, as measured by this proxy at least, is not strongly related to the various group and individual differences that exist in OAEs. Female latencies did not differ across the menstrual cycle, and the proxy length measure exhibited no sex difference (either for menses females vs. males or midluteal females vs. males) when the highpass noises were used. However, when the subjects were partitioned into Whites and Non-Whites, a substantial sex difference in cochlear length did emerge for the White group, although the correlations with OAEs remained low. Head size was not highly correlated with any of the ABR measures.

McFadden, Dennis; Garcia-Sierra, Adrian; Hsieh, Michelle D.; Maloney, Mindy M.; Champlin, Craig A.; Pasanen, Edward G.

2012-01-01

120

Heritabilities and genetic correlations of body weights and feather length in growing Muscovy selected in Taiwan.  

PubMed

1. Heritabilities and genetic correlations in the base population of a closed strain of Muscovy duck, moderately selected for body weight at 10 weeks of age, have been estimated from the data of 9 successive generations for the following traits: male and female body weight at 10 and 18 weeks of age (BW10m, BW18m, BW10f, BW18f) and length of the 8th primary feather at 10 weeks of age (F110m, F110f). 2. Multivariate REML with an animal model was used, pooling data from the 9 generations (3283 and 3289 male and female offspring respectively). The same trait expressed in male and female was considered as 2 different traits. 3. The 8th primary feather was longer in females than in males by 6% to 22% at 10 weeks of age. Body weight was heavier in males than in females by 42% to 58% at 10 weeks of age and by 57% to 75% at 18 weeks of age. 3. The heritability estimates for body weight traits showed moderate values, being a little higher for females than for males at the same age, increasing with age from h2=0.24 at BW10m to h2=0.43 at BW18f. 4. The heritability estimates for feather length showed that a greater response would be obtained in selection for male feather length (h2=0.37) than for female length (h2=0.14). Both have high genetic correlations with body weight so they could be indirectly improved. 5. Heritabilities of the difference in body weights between males and females at 10 weeks (h2=0.07) and 18 weeks of age (h2=0.10) were small, as well as for feather length (h2=0.10). It would probably be difficult to modify sexual dimorphism in body weight through selection. 6. Genetic correlations between BW10m, BW18m and BW10f, BW18f were respectively r(g)=0.77 and r(g)=0.80. They were larger for body weight at the same ages between males and females, r(g)=0.90 (r(g)=0.88 between F110m and F110f). Body weight in males and females at the same age should be better considered as 2 different traits in a selection programme. 7. The cumulated predicted genetic gains expressed per unity of the genetic standard deviation (sigma(g)) over the 8 generations of selection were 1.3 sigma(g) and 1.4 sigma(g) respectively for the BW10m and BW10f. The predicted correlated responses were 1.2 sigma(g) for body weights at 18 weeks of age, 0.9 sigma(g) and 0.7 sigma(g) for F110f and F110m respectively. PMID:10670671

Hu, Y H; Poivey, J P; Rouvier, R; Wang, C T; Tai, C

1999-12-01

121

Single-shot electron bunch length measurements using a spatial electro-optical autocorrelation interferometer  

SciTech Connect

A spatial, electro-optical autocorrelation (EOA) interferometer using the vertically polarized lobes of coherent transition radiation (CTR) has been developed as a single-shot electron bunch length monitor at an optical beam port downstream the 100 MeV preinjector LINAC of the Swiss Light Source. This EOA monitor combines the advantages of step-scan interferometers (high temporal resolution) [D. Mihalcea et al., Phys. Rev. ST Accel. Beams 9, 082801 (2006) and T. Takahashi and K. Takami, Infrared Phys. Technol. 51, 363 (2008)] and terahertz-gating technologies [U. Schmidhammer et al., Appl. Phys. B: Lasers Opt. 94, 95 (2009) and B. Steffen et al., Phys. Rev. ST Accel. Beams 12, 032802 (2009)] (fast response), providing the possibility to tune the accelerator with an online bunch length diagnostics. While a proof of principle of the spatial interferometer was achieved by step-scan measurements with far-infrared detectors, the single-shot capability of the monitor has been demonstrated by electro-optical correlation of the spatial CTR interference pattern with fairly long (500 ps) neodymium-doped yttrium aluminum garnet (Nd:YAG) laser pulses in a ZnTe crystal. In single-shot operation, variations of the bunch length between 1.5 and 4 ps due to different phase settings of the LINAC bunching cavities have been measured with subpicosecond time resolution.

Suetterlin, Daniel [PUBLICA Swiss Federal Pension Fund, CH-3000 Berne (Switzerland); Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Erni, Daniel [General and Theoretical Electrical Engineering (ATE), Faculty of Engineering, University of Duisburg-Essen, D-47048 Duisburg (Germany); Schlott, Volker [Department of Large Research Facilities, Paul Scherrer Institute, CH- 5232 Villigen (Switzerland); Sigg, Hans [Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, CH- 5232 Villigen (Switzerland); Jaeckel, Heinz [Department of Information Technology and Electrical Engineering, Electronics Laboratory, ETHZ, CH-8092 Zurich (Switzerland); Murk, Axel [Department of Microwave Physics, Institute of Applied Physics, University of Berne, CH-3012 Berne (Switzerland)

2010-10-15

122

TERRA Expression Levels Do Not Correlate with Telomere Length and Radiation Sensitivity in Human Cancer Cell Lines.  

PubMed

Mammalian telomeres are transcribed into long non-coding telomeric repeat-containing RNA (TERRA) molecules that seem to play a role in the maintenance of telomere stability. In human cells, CpG-island promoters drive TERRA transcription and are regulated by methylation. It was suggested that the amount of TERRA may be related to telomere length. To test this hypothesis we measured telomere length and TERRA levels in single clones isolated from five human cell lines: HeLa (cervical carcinoma), BRC-230 (breast cancer), AKG and GK2 (gastric cancers), and GM847 (SV40 immortalized skin fibroblasts). However, these two parameters did not correlate with each other. Moreover, cell survival to ?-rays did not show a significant variation among the clones, suggesting that, in this cellular system, the intra-population variability in telomere length and TERRA levels does not influence sensitivity to ionizing radiation. This conclusion was supported by the observation that in a cell line in which telomeres were greatly elongated by the ectopic expression of telomerase, TERRA expression levels and radiation sensitivity were similar to the parental HeLa cell line. PMID:23717814

Smirnova, Alexandra; Gamba, Riccardo; Khoriauli, Lela; Vitelli, Valerio; Nergadze, Solomon G; Giulotto, Elena

2013-05-10

123

TERRA Expression Levels Do Not Correlate with Telomere Length and Radiation Sensitivity in Human Cancer Cell Lines  

PubMed Central

Mammalian telomeres are transcribed into long non-coding telomeric repeat-containing RNA (TERRA) molecules that seem to play a role in the maintenance of telomere stability. In human cells, CpG-island promoters drive TERRA transcription and are regulated by methylation. It was suggested that the amount of TERRA may be related to telomere length. To test this hypothesis we measured telomere length and TERRA levels in single clones isolated from five human cell lines: HeLa (cervical carcinoma), BRC-230 (breast cancer), AKG and GK2 (gastric cancers), and GM847 (SV40 immortalized skin fibroblasts). However, these two parameters did not correlate with each other. Moreover, cell survival to ?-rays did not show a significant variation among the clones, suggesting that, in this cellular system, the intra-population variability in telomere length and TERRA levels does not influence sensitivity to ionizing radiation. This conclusion was supported by the observation that in a cell line in which telomeres were greatly elongated by the ectopic expression of telomerase, TERRA expression levels and radiation sensitivity were similar to the parental HeLa cell line.

Smirnova, Alexandra; Gamba, Riccardo; Khoriauli, Lela; Vitelli, Valerio; Nergadze, Solomon G.; Giulotto, Elena

2013-01-01

124

Electrostatic correlations and fluctuations for ion binding to a finite length polyelectrolyte  

PubMed Central

A statistical mechanical model is presented which explicitly accounts for the fluctuations, the electrostatic, and the excluded volume correlations for ions bound to a polyelectrolyte such as DNA. The method can be employed to treat a wide range of ionic conditions including multivalent ions. The microscopic framework of the theory permits the use of realistic finite length and grooved structural model for the polyelectrolyte and modeling of the finite size of the bound ions. Test against Monte Carlo simulations suggests that the theory can give accurate predictions for the ion distribution and the thermodynamic properties. For multivalent ions, the theory makes improved predictions as compared with the mean-field approach. Moreover, for long polyelectrolyte and dilute salt concentration, the theory predicts ion binding properties that agree with the counterion condensation theory.

Tan, Zhi-Jie; Chen, Shi-Jie

2008-01-01

125

Correlates of rehabilitation hospital length of stay among older African-American patients.  

PubMed Central

This study addresses a gap in the current literature on the correlates of rehabilitation hospital length of stay for older African Americans. Using data from 616 consecutively admitted rehabilitation patients who ranged in age from 50 to 103 years old, we tested the effect of patient's primary medical impairment; structural factors such as admit and discharge setting; level of depression (Geriatric Depression Scale); functional ability upon hospital admission (FIM score); and other control variables. Hierarchical linear regression models show that medical impairment alone was not a robust predictor of LOS. However, when controlling for structural and psychosocial factors, and medical condition, then circulation/amputation impairment was directly associated with longer LOS. Being unmarried or at risk for depression were also directly related to longer LOS. Consequently, rehabilitation administrators and hospital staff should note these findings to determine whether and how these factors affect discharge outcomes in their particular rehabilitative environments.

Mills, Terry L.; Lichtenberg, Peter A.; Wakeman, Melanie A.; Scott-Okafor, Hellena

2002-01-01

126

Eddy Correlation Flux Measurement System (ECOR) Handbook  

SciTech Connect

The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration.

Cook, DR

2011-01-31

127

Persistence Length of Human Cardiac ?-Tropomyosin Measured by Single Molecule Direct Probe Microscopy  

PubMed Central

?-Tropomyosin (?Tm) is the predominant tropomyosin isoform in adult human heart and constitutes a major component in Ca2+-regulated systolic contraction of cardiac muscle. We present here the first direct probe images of WT human cardiac ?Tm by atomic force microscopy, and quantify its mechanical flexibility with three independent analysis methods. Single molecules of bacterially-expressed human cardiac ?Tm were imaged on poly-lysine coated mica and their contours were analyzed. Analysis of tangent-angle (?(s)) correlation along molecular contours, second moment of tangent angles (), and end-to-end length (Le-e) distributions respectively yielded values of persistence length (Lp) of 41–46 nm, 40–45 nm, and 42–52 nm, corresponding to 1–1.3 molecular contour lengths (Lc). We also demonstrate that a sufficiently large population, with at least 100 molecules, is required for a reliable Lp measurement of ?Tm in single molecule studies. Our estimate that Lp for ?Tm is only slightly longer than Lc is consistent with a previous study showing there is little spread of cooperative activation into near-neighbor regulatory units of cardiac thin filaments. The Lp determined here for human cardiac ?Tm perhaps represents an evolutionarily tuned optimum between Ca2+ sensitivity and cooperativity in cardiac thin filaments and likely constitutes an essential parameter for normal function in the human heart.

Loong, Campion K. P.; Zhou, Huan-Xiang; Chase, P. Bryant

2012-01-01

128

Persistence length of human cardiac ?-tropomyosin measured by single molecule direct probe microscopy.  

PubMed

?-Tropomyosin (?Tm) is the predominant tropomyosin isoform in adult human heart and constitutes a major component in Ca²+-regulated systolic contraction of cardiac muscle. We present here the first direct probe images of WT human cardiac ?Tm by atomic force microscopy, and quantify its mechanical flexibility with three independent analysis methods. Single molecules of bacterially-expressed human cardiac ?Tm were imaged on poly-lysine coated mica and their contours were analyzed. Analysis of tangent-angle (?(s)) correlation along molecular contours, second moment of tangent angles (), and end-to-end length (L(e-e)) distributions respectively yielded values of persistence length (L(p)) of 41-46 nm, 40-45 nm, and 42-52 nm, corresponding to 1-1.3 molecular contour lengths (L(c)). We also demonstrate that a sufficiently large population, with at least 100 molecules, is required for a reliable L(p) measurement of ?Tm in single molecule studies. Our estimate that L(p) for ?Tm is only slightly longer than L(c) is consistent with a previous study showing there is little spread of cooperative activation into near-neighbor regulatory units of cardiac thin filaments. The L(p) determined here for human cardiac ?Tm perhaps represents an evolutionarily tuned optimum between Ca²+ sensitivity and cooperativity in cardiac thin filaments and likely constitutes an essential parameter for normal function in the human heart. PMID:22737252

Loong, Campion K P; Zhou, Huan-Xiang; Chase, P Bryant

2012-06-21

129

Partial coherence interferometry versus immersion ultrasonography for axial length measurement in children  

PubMed Central

PURPOSE To determine whether measurements obtained by partial coherence interferometry (PCI) correlate well with measurements obtained using immersion ultrasound (US) in children. SETTING Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, USA. DESIGN Evaluation of a diagnostic test or technology. METHODS The charts of pediatric patients who had cataract surgery from August 2008 to September 2009 were reviewed. Axial length (AL) measurements in the operative eye were obtained using PCI at the preoperative clinic visit and then using immersion US in the operating room before surgery. The data were compared to determine the degree of agreement. RESULTS The charts of 18 patients (27 eyes) were reviewed. Preoperative AL measurements by PCI were obtained in 21 eyes (78%). On average, the PCI-measured ALs were 0.1 mm less than the immersion US values (95% confidence interval, ?0.2 to ?0.1; P = .002). All eyes with an AL of 23.5 mm or less had lower PCI values than immersion US values. There was no systematic pattern of 1 measurement being greater or less than the other in eyes with an AL longer than 23.5 mm. CONCLUSIONS There is a systematic difference in AL measurement between PCI and immersion US, with PCI tending to give lower values, particularly in eyes with an AL longer than 23.5 mm. Depending on the length of the eye, a 0.1 mm error in AL measurement could result in a 0.25 to 0.75 diopter difference in intraocular lens calculation that could be clinically significant in some patients.

Lenhart, Phoebe D.; Hutchinson, Amy K.; Lynn, Michael J.; Lambert, Scott R.

2010-01-01

130

Generating nonclassical correlations without fully aligning measurements  

SciTech Connect

We investigate the scenario where spatially separated parties perform measurements in randomly chosen bases on an N-partite Greenberger-Horne-Zeilinger state. We show that without any alignment of the measurements, the observers will obtain correlations that violate a Bell inequality with a probability that rapidly approaches 1 as N increases and that this probability is robust against noise. We also prove that restricting these randomly chosen measurements to a plane perpendicular to a common direction will always generate correlations that violate some Bell inequality. Specifically, if each observer chooses their two measurements to be locally orthogonal, then the N observers will violate one of two Bell inequalities by an amount that increases exponentially with N. These results are also robust against noise and perturbations of each observer's reference direction from the common direction.

Wallman, Joel J.; Bartlett, Stephen D. [School of Physics, University of Sydney, Sydney, New South Wales 2006 (Australia); Liang, Yeong-Cherng [School of Physics, University of Sydney, Sydney, New South Wales 2006 (Australia); Group of Applied Physics, University of Geneva, CH-1211 Geneva 4 (Switzerland)

2011-02-15

131

Correlation Length Scales of Isotopic Variations Along Mid-Ocean Ridges and Upper Mantle Dynamics  

NASA Astrophysics Data System (ADS)

How isotopic variations in basalts erupted at the Earth's surface are linked to convective mixing in the underlying mantle is a central problem in geodynamics. The objective of this study is to quantify the length scales of upper mantle heterogeneity through spatial statistical analysis of MORB. We define a characteristic length scale, the scale of segregation L, computed from the spatial self-correlations for 3He/4He, 87Sr/86Sr, 143Nd/144Nd and 206,207,208Pb/204Pb in "zero age" lavas from mid-ocean ridges. Our working hypothesis is that small scale convection in the upper mantle controls dispersion of geochemical tracers. Differences in L between ocean basins may then be quantitatively related to unsteadiness in this convection, due to thickening of the lithosphere, plume impingement, or lateral temperature/compositional differences between continental and oceanic lithosphere induced by batholith formation. The correlation coefficient R, and the separation distance r, are calculated for every i,j pair of points. Ri,j is given by the product of the deviations in isotope composition from the population mean, normalized to the population variance, and R(r) is computed as an ensemble average. The total number of point pairs (N) for n sample locations is given by N=n(n-1)/2. For the global MORB data set (n=1265 and 735 for Sr and He, respectively), N exceeds 105 (799480 and 269745, respectively). A value of R(r) close to 1 indicates that an isotope ratio above (or below) the population average is likely to be associated with an above (or below) average value at a distance r away. A value of R(r) close to zero implies a random relationship, and a value close to -1 implies an anti-correlation. R(r) approaches unity at small r by definition, as points close together are from the same "clump" of mantle. The value of r at which R first goes to zero is denoted as r*. On a diagram of R(r) vs. r (the correlogram), the integral of R(r) from r=0 to r=r* is the scale of segregation L, a characteristic length related to "clump" size. Within the Earth's interior compositionally distinct regions may vary in size and shape and their boundaries may be diffuse. Lithosphere recycling at subduction zones and plume input from the lower mantle or transition zone are two ways by which compositionally distinct materials are introduced to the upper mantle. We use the L concept because it is a quantitative estimate of size which is precisely defined from spatially referenced geochemical data. Only a narrow range of L values is found within each ocean basin. In general, the isotope tracers have L values between 350-750 km for the N Atlantic, S Atlantic. and Indian Oceans. For the Pacific Ocean, L appears to be significantly less, between 100-180 km, indicating that mantle clumps in this region are smaller, in agreement with inferences based on the standard (non-spatial) statistical approach. Our results provide supporting evidence that dispersion of isotopic anomalies in the upper mantle is primarily controlled by small-scale convection. On a geological time scale, mantle flow is certainly unsteady. Small-scale convective cells, having their long axes aligned subparallel to the plate scale flow, are one simple manifestation of this unsteadiness. In Rayleigh-Benard convection, the amplitude and frequency of cellular wobble controls the extent of lateral mass transport (dispersion) between convective cells. Based on the spatial self-correlation of isotopic tracers, this dispersion appears to be more efficient in the Pacific upper mantle than elsewhere.

Graham, D. W.; Spera, F. J.

2003-12-01

132

Short delay measurement by polarity cross correlation  

NASA Astrophysics Data System (ADS)

A procedure for dealing with the limitations encountered in correlation flow measurement is presented. Using normal cross-correlation for flow measurement, the shape of a peak is determined by the bandwidth of the signal. Any attempt to improve resolution by sampling faster than is strictly necessary gives more points closer together on the correlation function, but the problem of determining the position of a rounded peak subject to noise remains. The procedure for dealing with this problem, presented here, is based on the fact that all signals share the same polarity autocorrelation function for delays less than 0.5/n, where n is the number of zero crossings per second, provided that zero crossings are separated by at least 0.5/n seconds.

Henry, R. M.; Zhang, L.

1990-02-01

133

High accuracy length measuring set up for optical encoder calibration  

NASA Astrophysics Data System (ADS)

Regarding nano-sciences and nano-technologies there is a permanent confusion between resolution and accuracy. Many sophisticated devices (APM, AFM, SNOM, confocal microscopes) characterized by their resolution, are used to observe at the nano-scale but they are far from being metrological devices, i.e. they do not measure. A metrological instrument must be traceable to the internationally accepted unit: meter in our case. We present an optical setup able to measure in micrometer range with nanometer resolution and ten nanometers accuracy. Its utility for MEMS geometrical parameter is obvious. The setup is working on a passive vibration-isolated table and contains a SIOS laser interferometer which assures the traceability of the measurement, a high resolution translation table, and a long working distance microscope. Few hundred measurements were done to a linear grating to measure the micrometric range pitch with nanometer accuracy. A 2 10-4 relative error was obtained.

Iordache, Iuliana; Iancu, O.; Schiopu, P.; Apostol, D.

2009-01-01

134

Bunch length measurements at the Advanced Photon Source (APS) linear accelerator  

SciTech Connect

Measurements of the APS linac micro-bunch length are performed by backphasing a single 2856-MHz, S-band linac waveguide and using a downstream spectrometer to observe the beam. By measuring the beam width in the dispersive plane as a function of rf power into the linac waveguide, the bunch length can be determined absolutely provided the beam energy and dispersion at the spectrometer are known. The bunch length determined in this fashion is used to calibrate a fifth-harmonic bunch length cavity which is used for real-time bunch length monitoring.

Sereno, N.S.; Fuja, R.; Gold, C.; Grelick, A.E.; Nassiri, A.; Song, J.J.; White, M.

1995-07-01

135

Evaluation of a new leg length measurement algorithm in hip arthroplasty.  

PubMed

Leg length inequality after hip arthroplasty is a major source of patient dissatisfaction and dysfunction. Despite numerous reported methods to intraoperatively determine leg length change, it remains a challenge. We developed a reliable and reproducible method to measure leg length change using surgical navigation. The method measures the change in position of the femur relative to the pelvis and the pelvic coordinate system without the need to establish a femoral coordinate system. We replaced 112 hips in 107 patients using the new leg length measurement algorithm. Leg length change measured at surgery was compared with leg length change as measured on magnification-corrected pre- and postoperative radiographs. Compared with radiographically measured leg length change, the leg length changes measured intraoperatively had a mean difference of -0.5 +/- 1.77 mm (range, -5-3.9 mm). We found no difference between radiographic data and navigation data. Leg length change measured using surgical navigation, measuring the change in position of the femur relative to the pelvic coordinate system, without establishing a femoral coordinate system is easy and reliable. PMID:17572632

Murphy, Stephen B; Ecker, Timo M

2007-10-01

136

Quantum Correlations and the Measurement Problem  

NASA Astrophysics Data System (ADS)

The transition from classical to quantum mechanics rests on the recognition that the structure of information is not what we thought it was: there are operational, i.e., phenomenal, probabilistic correlations that lie outside the polytope of local correlations. Such correlations cannot be simulated with classical resources, which generate classical correlations represented by the points in a simplex, where the vertices of the simplex represent joint deterministic states that are the common causes of the correlations. The `no go' hidden variable theorems tell us that we can't shoe-horn phenomenal correlations outside the local polytope into a classical simplex by supposing that something has been left out of the story. The replacement of the classical simplex by the quantum convex set as the structure representing probabilistic correlations is the analogue for quantum mechanics of the replacement of Newton's Euclidean space and time by Minkowski spacetime in special relativity. The nonclassical features of quantum mechanics, including the irreducible information loss on measurement, are generic features of correlations that lie outside the classical simplex. This paper is an elaboration of these ideas, which have their source in work by Pitowsky (J. Math. Phys. 27:1556, 1986; Math. Program. 50:395, 1991; Phys. Rev. A 77:062109, 2008), Garg and Mermin (Found. Phys. 14:1-39, 1984), Barrett (Phys. Rev. A 75:032304, 2007; Phys. Rev. A 7:022101, 2005) and others, e.g., Brunner et al. (arXiv:1303.2849, 2013), but the literature goes back to Boole (An Investigation of the Laws of Thought, Dover, New York, 1951). The final section looks at the measurement problem of quantum mechanics in this context. A large part of the problem is removed by seeing that the inconsistency in reconciling the entangled state at the end of a quantum measurement process with the definiteness of the macroscopic pointer reading and the definiteness of the correlated value of the measured micro-observable depends on a stipulation that is not required by the structure of the quantum possibility space. Replacing this stipulation by an alternative consistent stipulation is the first step to resolving the problem.

Bub, Jeffrey

2013-06-01

137

Myocardial Infarct Size Measurement in the Mouse Chronic Infarction Model: Comparison of Area- and Length-Based Approaches  

PubMed Central

Efficacy of potential treatments for myocardial infarction (MI) is commonly assessed by histological measurement of infarct size in rodent models. In experiments involving an acute MI setting, measurement of the infarcted area in tissue sections of the left ventricle (LV) is a standard approach to determine infarct size. This approach has also been used in the chronic infarct setting to measure infarct area several weeks post-MI. We tested the hypothesis that due to wall thinning that is known to occur in the chronic setting, the area measurement approach would be less appropriate. We compared infarct measurements in tissue sections based on (1) infarct area, (2) epicardial and endocardial infarct arc lengths, and (3) midline infarct arc length. Infarct size from all three measurement approaches correlated significantly with LV ejection fraction (LVEF) and wall motion abnormality. However, the infarct size values derived from area measurement were significantly smaller than those from the other measurements, and the range of values obtained was compressed 0.4-fold. The midline method was able to detect the expected size differences between infarcts of variable severity resulting from proximal vs. distal ligation of the coronary artery. Segmental infarct size was correlated with segmental wall motion abnormality. We conclude that both area- and length-based measurements can determine relative infarct size over a wide range of severity but the area-based measurements are substantially more compressed due to wall thinning, and that the estimation of infarct midlines is a simple, reliable approach to infarct size assessment.

Takagawa, Junya; Zhang, Yan; Wong, Maelene L.; Sievers, Richard E.; Kapasi, Neel K.; Wang, Yan; Yeghiazarians, Yerem; Lee, Randall J.; Grossman, William; Springer, Matthew L.

2009-01-01

138

Measuring roughness with dichromatic speckle correlation  

NASA Astrophysics Data System (ADS)

The most established way to inspect machined surfaces is measuring with profilometers. Roughness measurements by these methods take plenty of time and an on-line integration in production facilities is not feasible due to different reasons. Over two decades ago, Goodman and Parry discovered the correlation between laser speckles of different light wavelengths and surface roughness. Since then several authors have been working on this topic. Nevertheless, industrial sensors based on the speckle correlation phenomenon measuring a roughness value are not available yet. In this article a new method is described, which is suitable for measuring the roughness of surfaces online under production conditions. The surface which is to be inspected is illuminated by a dichromatic laser beam. The scattered light is converted by lenses, and the far field speckles are detected in the Fourier plane of the lenses by a separate CCD-array for each wavelength. The CCD-data are captured by a frame grabber and stored for evaluation. A digital computer processes the data by calculating 2D-cross correlation functions of the two related speckle patterns for the different light wavelengths. The maximum values of the cross correlation function represents the correlation coefficient, which can then be translated into the root mean square of the surface heights of the workpiece. The main benefit of the method described is the feasibility of measuring roughness during processing. This is achieved by a time synchronous detection of speckle patterns of two different wavelengths, which are used to determine the roughness of a surface. The basic measuring time is determined by the shutter speed of the cameras, which is in the pilot project 1/10000 s. Therefore, only vibration frequencies above 1 kHz disturb the measuring results. A further reduction of the measuring time will be no major problem. Thus any realtime roughness measuring problem can be solved this way. This article describes the state of the art and the state of the experimental investigations measuring roughness by means of this new measuring process.

Peters, Joerg; Lehmann, Peter; Schoene, Armin

1996-09-01

139

Small-Angle Neutron Scattering Studies of Magnetic Correlation Lengths in Nanoparticle Assemblies  

NASA Astrophysics Data System (ADS)

Small-angle neutron scattering (SANS) measurements of ordered arrays of surfactant-coated magnetic nanoparticle reveal characteristic length scales associated with interparticle and intraparticle magnetic ordering. The high degree of uniformity in the monodisperse nanoparticle size and spacing leads to a pronounced diffraction peak and allows for a straightforward determination of these length scales [1]. There are notable differences in these length scales depending on the particle moment, which depends on the material (Fe, Co, Fe3O4) and diameter, and also on whether the metal particle core is surrounded by an oxide shell. For 8.5 nm particles containing an Fe core and thick Fe3O4 shell, evidence of a spin flop phase is seen in the magnetite shell when a field is applied , but not when the shell thickness is ˜0.5 nm [2]. 8.0 nm particles with an e-Co core and 0.75 nm CoO shell show no exchange bias effects while similar particles with a 2 nm thick shell so significant training effects below 90 K. Polarized SANS studied of 7 nm Fe3O4 nanoparticle assemblies show the ability to resolve the magnetization components in 3D. [4pt] [1] M. Sachan, C. Bonnoit, S. A. Majetich, Y. Ijiri, P. O. Mensah-Bonsu, J. A. Borchers, and J. J. Rhyne, Appl. Phys. Lett. 92, 152503 (2008). [0pt] [2] Yumi Ijiri, Christopher V. Kelly, Julie A. Borchers, James J. Rhyne, Dorothy F. Farrell, Sara A. Majetich, Appl. Phys. Lett. 86, 243102-243104 (2005). [0pt] [3] K. L. Krycka, R. Booth, J. A. Borchers, W. C. Chen, C. Conlon, T. Gentile, C. Hogg, Y. Ijiri, M. Laver, B. B. Maranville, S. A. Majetich, J. Rhyne, and S. M. Watson, Physica B (submitted).

Majetich, Sara

2009-03-01

140

Simultaneous Water Vapor and Dry Air Path Length Measurements with the Keck Interferometer Nuller  

NASA Astrophysics Data System (ADS)

K-band phase and group delay measurements of atmospheric turbulence are used as part of the Keck Interferometer nuller cophasing system to provide high-bandwidth path length compensation at N band. Because of atmospheric dispersion, the path length fluctuations from dry air and water vapor must be estimated separately, and the computation of the N-band feedforward quantities from the K-band measurements is described. Simultaneous K and N-band sky data are presented that show good correspondence with the underlying atmospheric models. Simultaneous power spectra of dry air and water vapor path length turbulence measured on an 85 m baseline with the Keck Interferometer over 44 nights between 2007 June and 2009 July are also presented. From the median power spectra, the rms path length fluctuations at band from water vapor are found to be 48 times smaller than those for dry air, and the absolute level of the water vapor path length fluctuations is found to be a factor of 2 smaller than predicted based on archival data from the CSO test radio interferometer. It is postulated that part of the difference is attributable to surface-layer water vapor turbulence, which would be smaller at the elevation of the Keck telescopes than for the test antennas, similar to surface-layer effects seen in dry air seeing at Mauna Kea. The midfrequency power spectral amplitude better characterizes the residuals for a feedforward compensation system, and this value is found to be a factor of 65 smaller at K band for water vapor than for dry air; the difference compared to the ratio of the rms values is attributable to the lower effective wind speed of the water vapor turbulence, and thus lower control bandwidths are required for compensation than a simple scaling based on rms fluctuations would indicate. The water vapor coherence time is also shown to have modest correlations with both precipitable water vapor and the dry air coherence time, although the variability of the water vapor turbulence strength is larger than that of the dry air turbulence.

Colavita, M. M.

2010-05-01

141

Crown-rump length discordance in twins in the first trimester and its correlation with perinatal complications*  

PubMed Central

BACKGROUND: A difference more than 15-40% in birth weight of twins can predict perinatal complications. As significant difference in twins growth has a very important effect on pregnancy and perinatal complications, this study aimed to evaluate crown-rump length discordance (?CRL) in the first trimester of pregnancy and its correlation with perinatal complications. METHODS: A total number of 118 women in the first trimester of twin pregnancy underwent ultrasound examination to measure ?CRL. Then, at the time of delivery, perinatal complications in twins were recorded and the correlation between ?CRL and perinatal complications were evaluated. RESULTS: Among 118 studied mothers with twin pregnancy, ?CRL was normal (< 11%) in 96 cases (81.4%) and high (? 11%) in 22 cases (18.6%). Birth weight discordance was normal (< 20%) in 103 cases (87.3%) and above normal (? 20%) in 15 cases (12.7%). The results revealed a significant correlation between higher frequency of small for gestational age (SGA) and high ?CRL (more than 11%) (p = 0.01). CONCLUSIONS: Our study concluded that SGA has a significant relationship with high ?CRL (> 11%).

Shahshahan, Zahra; Hashemi, Maryam

2011-01-01

142

Measurement and analysis of sarcomere length in rat cardiomyocytes in situ and in vitro  

PubMed Central

Sarcomere length (SL) is an important determinant and indicator of cardiac mechanical function; however, techniques for measuring SL in living, intact tissue are limited. Here, we present a technique that uses two-photon microscopy to directly image striations of living cells in cardioplegic conditions, both in situ (Langendorff-perfused rat hearts and ventricular tissue slices, stained with the fluorescent marker di-4-ANEPPS) and in vitro (acutely isolated rat ventricular myocytes). Software was developed to extract SL from two-photon fluorescence image sets while accounting for measurement errors associated with motion artifact in raster-scanned images and uncertainty of the cell angle relative to the imaging plane. Monte-Carlo simulations were used to guide analysis of SL measurements by determining error bounds as a function of measurement path length. The mode of the distribution of SL measurements in resting Langendorff-perfused heart is 1.95 ?m (n = 167 measurements from N = 11 hearts) after correction for tissue orientation, which was significantly greater than that in isolated cells (1.71 ?m, n = 346, N = 9 isolations) or ventricular slice preparations (1.79 ?m, n = 79, N = 3 hearts) under our experimental conditions. Furthermore, we find that edema in arrested Langendorff-perfused heart is associated with a mean SL increase; this occurs as a function of time ex vivo and correlates with tissue volume changes determined by magnetic resonance imaging. Our results highlight that the proposed method can be used to monitor SL in living cells and that different experimental models from the same species may display significantly different SL values under otherwise comparable conditions, which has implications for experiment design, as well as comparison and interpretation of data.

Camelliti, P.; Bollensdorff, C.; Stuckey, D. J.; Picton, G.; Burton, R. A. B.; Clarke, K.; Kohl, P.

2010-01-01

143

Length limitations of far-end crosstalk measurements in multipair telephone cables  

NASA Astrophysics Data System (ADS)

Far-End Crosstalk testing of production length cables is subject to possible measurement errors especially at the 6300 KHz test frequency of Bellcore TA series cable specifications. Cable attenuation at high frequencies and long lengths can reduce the signal level seen by the measuring system. As the signal levels approach the measurement system's noise level, error is introduced into the measurements. Relative Signal Level curves are described which aid in determining if errors due to measuring system noise floor effects are present.

Normile, James M.

1986-11-01

144

The accuracy of length measurements using different intravascular ultrasound motorized transducer pullback systems  

Microsoft Academic Search

Accurate length measurements by intravascular ultrasound (IVUS) are necessary for stent length selection and for IVUS volumetric\\u000a analysis. The comparative accuracy of commercially available transducer pullback systems––a necessity for accurate IVUS length\\u000a and volume measurements––has never been studied. We evaluated the accuracy of four IVUS pullback systems by studying 180 patients\\u000a (45 in each group) who had been treated with

Kaoru Tanaka; Stéphane G. Carlier; Gary S. Mintz; Koichi Sano; Xuebo Liu; Kenichi Fujii; Jose de Ribamar Costa; Joanna Lui; Jeffrey W. Moses; Gregg W. Stone; Martin B. Leon

2007-01-01

145

FIBER LENGTH DISTRIBUTION MEASUREMENT FOR LONG GLASS AND CARBON FIBER REINFORCED INJECTION MOLDED THERMOPLASTICS  

SciTech Connect

Procedures for fiber length distribution (FLD) measurement of long fiber reinforced injection molded thermoplastics were refined for glass and carbon fibers. Techniques for sample selection, fiber separation, digitization and length measurement for both fiber types are described in detail. Quantitative FLD results are provided for glass and carbon reinforced polypropylene samples molded with a nominal original fiber length of 12.7 mm (1/2 in.) using equipment optimized for molding short fiber reinforced thermoplastics.

Kunc, Vlastimil [ORNL; Frame, Barbara J [ORNL; Nguyen, Ba N. [Pacific Northwest National Laboratory (PNNL); TuckerIII, Charles L. [University of Illinois, Urbana-Champaign; Velez-Garcia, Gregorio [Virginia Polytechnic Institute and State University

2007-01-01

146

Sonographic Cervical Length Measurement before Labor Induction in Term Nulliparous Women  

Microsoft Academic Search

Objective: The purpose of the study was to determine if transvaginal sonographic measurement of the cervical length is a useful method to predict successful labor induction in nulliparas. Methods: 137 women who were scheduled for medically indicated induction of labor had a transvaginal sonographic measurement of the cervical length before labor induction. Inclusion criteria were: (1) singleton pregnancy; (2) gestational

George Daskalakis; Nikolaos Thomakos; Leonardos Hatziioannou; Spyros Mesogitis; Nikolaos Papantoniou; Aris Antsaklis

2006-01-01

147

Bunch Length and Impedance Measurements at SPEAR3  

SciTech Connect

Streak camera measurements were made at SPEAR3 to characterize longitudinal coupling impedance. For the nominal optics, data was taken at three rf voltages and a single-bunch current range of 0-20mA. Both bunchcentroid phase shift and bunch lengthening were recorded to extract values for resistive and reactive impedance. An (R+L) and a Q=1 model were then back-substituted into the Haissinski equation and compared with raw profile data. In the short bunch (low-{alpha}) mode, distribution 'bursting' was observed.

Corbett, W.J.; Cheng, W.X.; Fisher, A.S.; Huang, X.; /SLAC

2011-11-02

148

Measuring the robson angle in vacuum arcs of various length  

NASA Astrophysics Data System (ADS)

It is established that the Robson angle, which determines the direction of motion of a cathode spot of vacuum arc in a homogeneous electric field sloped relative to the cathode, depends mostly on the inter-electrode gap width. The dependence of the Robson angle on the field slope at various gap widths has been measured for molybdenum and tungsten cathodes. The knowledge of this angle is necessary for correct choice of the optimum magnetic field configuration controlling the cathode spot dynamics in setups for vacuum-arc deposition of various coatings and in vacuum commutation devices.

Zabello, K. K.; Chaly, A. M.; Shkol'nik, S. M.

2013-01-01

149

Cavitation threshold measurements for microsecond length pulses of ultrasound.  

PubMed

The acoustic cavitation threshold of an aqueous solution has been measured at megahertz frequencies as a function of pulse width and pulse repetition frequency for various combinations of these quantities. The fluid tested was a 0.1M KOH-H3BO3 buffer solution with pH 10.9, which contained luminol, was saturated with argon, and filtered to 25 mu. The presence of cavitation was detected by a photomultiplier tube that required the emission of visible light that was both larger in magnitude and longer in duration than a preset criterion. It was observed that the cavitation threshold of water under pulse conditions decreases both when the pulse width is fixed and the pulse repetition frequency is increased, and when the pulse repetition frequency is fixed and the pulse width is increased. Acoustic cavitation thresholds measured in aqueous solutions are significantly less than those acoustic pressures associated with instruments that are currently in widespread use in medicine. PMID:3411016

Fowlkes, J B; Crum, L A

1988-06-01

150

A tool for measuring the bending length in thin wires  

NASA Astrophysics Data System (ADS)

Great effort is currently being put into the development and construction of the second generation, advanced gravitational wave detectors, Advanced Virgo and Advanced LIGO. The development of new low thermal noise suspensions of mirrors, based on the experience gained in the previous experiments, is part of this task. Quasi-monolithic suspensions with fused silica wires avoid the problem of rubbing friction introduced by steel cradle arrangements by directly welding the wires to silica blocks bonded to the mirror. Moreover, the mechanical loss level introduced by silica (?fs ~ 10-7 in thin fused silica wires) is by far less than the one associated with steel. The low frequency dynamical behaviour of the suspension can be computed and optimized, provided that the wire bending shape under pendulum motion is known. Due to the production process, fused silica wires are thicker near the two ends (necks), so that analytical bending computations are very complicated. We developed a tool to directly measure the low frequency bending parameters of fused silica wires, and we tested it on the wires produced for the Virgo+ monolithic suspensions. The working principle and a set of test measurements are presented and explained.

Lorenzini, M.; Cagnoli, G.; Cesarini, E.; Losurdo, G.; Martelli, F.; Piergiovanni, F.; Vetrano, F.; Viceré, A.

2013-03-01

151

Measuring velocity ratios with correlation functions  

NASA Astrophysics Data System (ADS)

We show how to determine the ratio of the transverse velocity of a source to the velocity of emitted particles, using split-bin correlation functions. The technique is to measure S2 and S?2, subtract the contributions from the single-particle distribution, and take the ratio as the bin size goes to zero. We demonstrate the technique for two cases: each source decays into two particles, and each source emits a large number of particles.

Seibert, David; Haglin, Kevin; Gale, Charles

1993-09-01

152

Sensor for Radiometric Measurements with Pyroelectric Detector and Reflecting Objective of Long Focal Length.  

National Technical Information Service (NTIS)

A sensor which permits radiometric and pyrometric measurements is described. The sensor is equipped with a cassegrain reflecting objective of long focal length. Radiation measurements are made in a chopped radiation mode at chopping frequencies between 6 ...

U. Mester W. Glockmann E. Pudelko

1980-01-01

153

Correlation of microscopic length scales of ion dynamics with network structure in lithium-iodide-doped lithium metaphosphate glasses  

NASA Astrophysics Data System (ADS)

In this paper we have studied the correlation of microscopic length scales of ion dynamics with the network structure in lithium-iodide-doped lithium metaphosphate glasses. We have obtained microscopic length scales for ion dynamics, such as the characteristic mean square displacement and the spatial extent of sub-diffusive motion of the lithium ions. We have observed that the lithium ions have to travel a smaller distance to overcome the nearest percolation barriers in order to perform long-range diffusion. The phosphate chain lengths shorten with the addition of lithium iodide to metaphosphate glasses. We have also studied the network structure of these glasses, and a correlation between the length scales of ion dynamics and the network structure has been obtained.

Shaw, A.; Ghosh, A.

2012-12-01

154

Measuring body length of male sperm whales from their clicks: the relationship between inter-pulse intervals and photogrammetrically measured lengths.  

PubMed

Sperm whales (Physeter macrocephalus) emit short, broadband clicks which often include multiple pulses. The time interval between these pulses [inter-pulse interval (IPI)] represents the two-way time for a pulse to travel between the air sacs located at either end of the sperm whale's head. The IPI therefore, is a proxy of head length which, using an allometric relationship, can be used to estimate total body length. Previous studies relating IPI to an independent measure of length have relied on very small sample sizes and manual techniques for measuring IPI. Sound recordings and digital stereo photogrammetric measurements of 21 individuals were made off Kaikoura, New Zealand, and, in addition, archived recordings of whales measured with a previous photogrammetric system were reanalyzed to obtain a total sample size of 33 individuals. IPIs were measured automatically via cepstral analysis implemented via a software plug-in for pamguard, an open-source software package for passive acoustic monitoring. IPI measurements were highly consistent within individuals (mean CV=0.63%). The new regression relationship relating IPI (I) and total length (T) was found to be T=1.258I+5.736 (r(2)=0.77, p<0.001). This new regression provides a better fit than previous studies of large (> 11 m) sperm whales. PMID:21786922

Growcott, Abraham; Miller, Brian; Sirguey, Pascal; Slooten, Elisabeth; Dawson, Stephen

2011-07-01

155

Nonsymmetrized Correlations in Quantum Noninvasive Measurements  

NASA Astrophysics Data System (ADS)

A long-standing problem in quantum mesoscopic physics is which operator order corresponds to noise expressions like ?I(-?)I(?)?, where I(?) is the measured current at frequency ?. Symmetrized order describes a classical measurement while nonsymmetrized order corresponds to a quantum detector, e.g., one sensitive to either emission or absorption of photons. We show that both order schemes can be embedded in quantum weak-measurement theory taking into account measurements with memory, characterized by a memory function which is independent of a particular experimental detection scheme. We discuss the resulting quasiprobabilities for different detector temperatures and how their negativity can be tested on the level of second-order correlation functions already. Experimentally, this negativity can be related to the squeezing of the many-body state of the transported electrons in an ac-driven tunnel junction.

Bednorz, Adam; Bruder, Christoph; Reulet, Bertrand; Belzig, Wolfgang

2013-06-01

156

Bunch Length Measurement and the Beam Spectra Observation Through High Power RF Waveguide System  

SciTech Connect

A wide-band pick-up, which is mounted on the wall of waveguide between the klystron and the RF cavity, has been developed for measuring beam spectra in KEKB. The spectrum between 5 GHz and 20GHz is taken to calculate the bunch length. And the synchrotron oscillation is observed as the side band of revolution peak. The bunch length and synchrotron frequency are measured under the different momentum compaction factors {alpha} and different total RF voltages Vc. Measured bunch length is compared with the measurement of streak camera.

Hong, B

2004-02-25

157

A Prospective Study of Telomere Length Measured by Monochrome Multiplex Quantitative PCR and Risk of Lung Cancer  

PubMed Central

Purpose Telomere length plays an important role in chromosomal stability and tumorigenesis, and its measurement in peripheral white blood cell DNA may be a predictor of the development of lung cancer. Experimental Design Using a new method - monochrome multiplex quantitative PCR -which reduces measurement variability, we compared telomere length relative to standard DNA in white blood cell DNA in 229 incident male lung cancer cases and 229 matched controls within the prospective Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study of male smokers. Results Median (10th, 90th percentile) telomere length was 1.13 (0.86, 1.45) in cases and 1.08 (0.85, 1.38) in controls (P = 0.038). Telomere length was inversely associated with pack-years of smoking (Spearman correlation r = ?0.16, P = 0.02) among controls. Compared to subjects with shorter telomere length (? median), subjects with greater telomere length (> median) had a 1.6-fold (95% CI, 1.06–2.36) increased risk of lung cancer. There was a significant linear relationship between quartiles of telomere length and risk of lung cancer (odds ratios (95% confidence intervals) by quartile: 1.00, 0.98 (0.55–1.73), 1.62 (0.95–2.77), and 1.50 (0.84–2.68); Ptrend = 0.05). In addition, subgroup analysis showed that greater telomere length was associated with increased risk of lung cancer among heavy smokers (> 38 years) (OR, 1.90; 95% CI, 1.00–3.59) but not among light smokers (? 38 years) (OR, 1.08; 95% CI, 0.56–2.11) (Pinteraction = 0.01). Conclusions Our results suggest that greater telomere length may be associated with higher risk of lung cancer among male smokers.

Shen, Min; Cawthon, Richard; Rothman, Nathaniel; Weinstein, Stephanie J.; Virtamo, Jarmo; Hosgood, H. Dean; Lim, Unhee; Albanes, Demetrius; Lan, Qing

2012-01-01

158

Microsatellite length variation in candidate genes correlates with habitat in the gilthead sea bream Sparus aurata.  

PubMed

The genetic basis and evolutionary implications of local adaptation in high gene flow marine organisms are still poorly understood. In several Mediterranean fish species, alternative migration patterns exist between individuals entering coastal lagoons that offer favourable conditions for growth and those staying in the sea where environmental conditions are less subject to rapid and stressful change. Whether these coexisting strategies are phenotypically plastic or include a role for local adaptation through differential survival needs to be determined. Here, we explore the genetic basis of alternate habitat use in western Mediterranean populations of the gilthead sea bream (Sparus aurata). Samples from lagoonal and open-sea habitats were typed for three candidate gene microsatellite loci, seven anonymous microsatellites and 44 amplified fragment length polymorphism markers to test for genotype-environment associations. While anonymous markers globally indicated high levels of gene flow across geographic locations and habitats, non-neutral differentiation patterns correlated with habitat type were found at two candidate microsatellite loci located in the promoter region of the growth hormone and prolactin genes. Further analysis of these two genes revealed that a mechanism based on habitat choice alone could not explain the distribution of genotype frequencies at a regional scale, thus implying a role for differential survival between habitats. We also found an association between allele size and habitat type, which, in the light of previous studies, suggests that polymorphisms in the proximal promoter region could influence gene expression by modulating transcription factor binding, thus providing a potential explanatory link between genotype and growth phenotype in nature. PMID:23061421

Chaoui, Lamya; Gagnaire, Pierre-Alexandre; Guinand, Bruno; Quignard, Jean-Pierre; Tsigenopoulos, Costas; Kara, M Hichem; Bonhomme, François

2012-10-12

159

Effect of genomic long-range correlations on DNA persistence length: from theory to single molecule experiments.  

PubMed

Sequence dependency of DNA intrinsic bending properties has been emphasized as a possible key ingredient to in vivo chromatin organization. We use atomic force microscopy (AFM) in air and liquid to image intrinsically straight (synthetic), uncorrelated (hepatitis C RNA virus) and persistent long-range correlated (human) DNA fragments in various ionic conditions such that the molecules freely equilibrate on the mica surface before being captured in a particular conformation. 2D thermodynamic equilibrium is experimentally verified by a detailed statistical analysis of the Gaussian nature of the DNA bend angle fluctuations. We show that the worm-like chain (WLC) model, commonly used to describe the average conformation of long semiflexible polymers, reproduces remarkably well the persistence length estimates for the first two molecules as consistently obtained from (i) mean square end-to-end distance measurement and (ii) mean projection of the end-to-end vector on the initial orientation. Whatever the operating conditions (air or liquid, concentration of metal cations Mg(2+) and/or Ni(2+)), the persistence length found for the uncorrelated viral DNA underestimates the value obtained for the straight DNA. We show that this systematic difference is the signature of the presence of an uncorrelated structural intrinsic disorder in the hepatitis C virus (HCV) DNA fragment that superimposes on local curvatures induced by thermal fluctuations and that only the entropic disorder depends upon experimental conditions. In contrast, the WLC model fails to describe the human DNA conformations. We use a mean-field extension of the WLC model to account for the presence of long-range correlations (LRC) in the intrinsic curvature disorder of human genomic DNA: the stronger the LRC, the smaller the persistence length. The comparison of AFM imaging of human DNA with LRC DNA simulations confirms that the rather small mean square end-to-end distance observed, particularly for G+C-rich human DNA molecules, more likely results from a large-scale intrinsic curvature due to a persistent distribution of DNA curvature sites than from some increased flexibility. PMID:20345170

Moukhtar, Julien; Faivre-Moskalenko, Cendrine; Milani, Pascale; Audit, Benjamin; Vaillant, Cedric; Fontaine, Emeline; Mongelard, Fabien; Lavorel, Guillaume; St-Jean, Philippe; Bouvet, Philippe; Argoul, Françoise; Arneodo, Alain

2010-04-22

160

Correlation Length Scales of Isotopic Variations Along Mid-Ocean Ridges and Upper Mantle Dynamics  

Microsoft Academic Search

How isotopic variations in basalts erupted at the Earth's surface are linked to convective mixing in the underlying mantle is a central problem in geodynamics. The objective of this study is to quantify the length scales of upper mantle heterogeneity through spatial statistical analysis of MORB. We define a characteristic length scale, the scale of segregation L, computed from the

D. W. Graham; F. J. Spera

2003-01-01

161

Trait Attribution as a Function of Hair Length and Correlates of Subjects' Preferences for Hair Style  

Microsoft Academic Search

The study was designed to examine the trait attribution process of American female college students to male stimulus targets differing in hair length and to explore the relationship between differences in preferences for hair length and differences in S characteristics of the perceiver. In a between Ss design, groups of females (N = 90) rated male stimulus targets of various

Kevin Peterson; James P. Curran

1976-01-01

162

A comparison of the use of radar images and neutron probe data to determine the horizontal correlation length of water content  

NASA Astrophysics Data System (ADS)

Surface-based ground-penetrating radar data were collected at the Hanford Site in Washington, U.S.A. to assess the use of radar reflection images as a means of quantifying the spatial variability of subsurface water content. Available at the selected test site were two sets of water content data derived from neutron probe measurements that had been made to a depth of ˜18 m in 32 wells in 1980 and 1995. The comparison of probe-derived water content data, synthetic radar data, and the acquired radar data indicated a good correspondence between the changes in probe-derived water content and the location of reflections in the radar data. Geostatistical analysis was conducted on the two sets of probe-derived water content values and the amplitudes of the reflections in the radar reflection image to determine the horizontal correlation length of water content. The experimental semivariograms for the water content data were fit with a single exponential model with a correlation length of 10 m. The semivariogram for the radar data was fit with a nested structure containing a dominant long-range structure with a correlation length of 14 m, and a smaller-scale structure with a correlation length of 0.3 m. Quantifying the scale triplet—the spacing, extent, and support—for the two forms of measurement provided a framework for comparing and assessing the derived correlation structures. This approach also highlighted the importance of identifying methods for properly determining the scale of radar measurements required for the imaging of subsurface water content.

Knight, Rosemary J.; Irving, James D.; Tercier, Paulette; Freeman, Gene J.; Murray, Chris J.; Rockhold, Mark L.

163

In vivo validation of intravascular ultrasound length measurements using a motorized transducer pullback system  

Microsoft Academic Search

With use of endovascular targets of known length, IVUS lesion length measurements have been validated in vivo. Intravascular ultrasound imaging using motorized pullback of the transducer and imaging core through a stationary imaging sheath may prove to be a useful clinical and experimental adjunct to conventional cross-sectional image analysis.

Rolf T. Fuessl; Gary S. Mintz; Augusto D. Pichard; Kenneth M. Kent; Lowell F. Satler; Jeffrey J. Popma; Martin B. Leon

1996-01-01

164

Bunch Length Measurements at the JLab FEL Using Coherent Transition and Synchrotron Radiation.  

National Technical Information Service (NTIS)

The JLab FEL is routinely operated with sub-picosecond bunches. The short bunch length is important for high gain of the FEL. Coherent transition radiation has been used for the bunch length measurements for many years. This diagnostic can be used only in...

G. Neil J. Coleman J. M. Klopf K. Jordan P. Evtushenko

2006-01-01

165

Bunch Length Measurements at the JLab FEL Using Coherent Transition and Synchrotron Radiation  

Microsoft Academic Search

The JLab FEL is routinely operated with sub-picosecond bunches. The short bunch length is important for high gain of the FEL. Coherent transition radiation has been used for the bunch length measurements for many years. This diagnostic can be used only in the pulsed beam mode. It is our goal to run the FEL with CW beam and a 74.85

Pavel Evtushenko; James Coleman; Kevin Jordan; J. Michael Klopf; George Neil; Gwyn Williams

2006-01-01

166

Measurement of MODIS optics effective focal length, distortion, and modulation transfer function  

NASA Astrophysics Data System (ADS)

A combination MODIS optics characteristics, short back focal length, and relatively distorting optics, has required major revisions in techniques used earlier to characterize effective focal length (EFL) and modulation transfer function (MTF) in the thematic mapper (TM) project. This paper compares measurement approaches used to characterize TM optics and revised methodology intended to characterize MODIS optics at an integration and assembly level.

Thurlow, Paul E.; Cline, Richard W.

1993-08-01

167

Telomere length correlates with histopathogenesis according to the germinal center in mature B-cell lymphoproliferative disorders.  

PubMed

In this study we investigated telomere restriction fragment (TRF) length in a panel of mature B-cell lymphoproliferative disorders (MBCLDs) and correlated this parameter with histology and histopathogenesis in relation to the germinal center (GC). We assessed 123 MBCLD samples containing 80% or more tumor cells. TRF length was evaluated by Southern blot analysis using a chemiluminescence-based assay. GC status was assessed through screening for stable and ongoing somatic mutations within the immunoglobulin heavy-chain genes. Median TRF length was 6170 bp (range, 1896-11 200 bp) and did not correlate with patient age or sex. TRF length was greater in diffuse large cell lymphoma, Burkitt lymphoma, and follicular lymphoma (medians: 7789 bp, 9471 bp, and 7383 bp, respectively) than in mantle cell lymphoma and chronic lymphocytic leukemia (medians: 3582 bp and 4346 bp, respectively). GC-derived MBCLDs had the longest telomeres, whereas those arising from GC-inexperienced cells had the shortest (P < 10(-9)). We conclude that (1) TRF length in MBCLD is highly heterogeneous; (2) GC-derived tumors have long telomeres, suggesting that minimal telomere erosion occurs during GC-derived lymphomagenesis; and (3) the short TRF lengths of GC-inexperienced MBCLDs indicates that these neoplasms are good candidates for treatment with telomerase inhibitors, a class of molecules currently the subject of extensive preclinical evaluation. PMID:14988160

Ladetto, Marco; Compagno, Mara; Ricca, Irene; Pagano, Marco; Rocci, Alberto; Astolfi, Monica; Drandi, Daniela; di Celle, Paola Francia; Dell'Aquila, Maria; Mantoan, Barbara; Vallet, Sonia; Pagliano, Gloria; De Marco, Federica; Francese, Roberto; Santo, Loredana; Cuttica, Alessandra; Marinone, Carlo; Boccadoro, Mario; Tarella, Corrado

2004-02-26

168

Maternal and ambient environmental effects of light on germination in Plantago lanceolata: correlated responses to selection on leaf length  

Microsoft Academic Search

1. Seeds from artificial selection lines were exposed to different maternal and ambient conditions, simulating sunlight and vegetation shade. 2. Lines selected for longer leaves also produced larger seeds, indicating a positive genetic correlation between leaf length and seed size. 3. Light conditions during maturation had no large effect on seed size. 4. Seed germination was reduced by a low

A. Van Hinsberg

1998-01-01

169

Correlation length of the 1D Hubbard model at half-filling: Equal-time one-particle Green's function  

NASA Astrophysics Data System (ADS)

The asymptotics of the equal-time one-particle Green's function of the half-filled one-dimensional Hubbard model is studied at finite temperature. We calculate its correlation length by evaluating the largest and the second largest eigenvalues of the Quantum Transfer Matrix (QTM). In order to allow for the genuinely fermionic nature of the one-particle Green's function, we employ the fermionic formulation of the QTM based on the fermionic R-operator of the Hubbard model. The purely imaginary value of the second largest eigenvalue reflects the kF( = ?/2) oscillations of the one-particle Green's function at half-filling. By solving numerically the Bethe ansatz equations with Trotter numbers up to N = 10240, we obtain accurate data for the correlation length at finite temperatures down into the very low-temperature region. The correlation length remains finite even at T = 0 due to the existence of the charge gap. Our numerical data confirm Stafford and Millis' conjecture regarding an analytic expression for the correlation length at T = 0.

Umeno, Y.; Shiroishi, M.; Klümper, A.

2003-05-01

170

Measurement of the length of pedestrian crossings and detection of traffic lights from image data  

NASA Astrophysics Data System (ADS)

This paper proposes a method for measurement of the length of a pedestrian crossing and for the detection of traffic lights from image data observed with a single camera. The length of a crossing is measured from image data of white lines painted on the road at a crossing by using projective geometry. Furthermore, the state of the traffic lights, green (go signal) or red (stop signal), is detected by extracting candidates for the traffic light region with colour similarity and selecting a true traffic light from them using affine moment invariants. From the experimental results, the length of a crossing is measured with an accuracy such that the maximum relative error of measured length is less than 5% and the rms error is 0.38 m. A traffic light is efficiently detected by selecting a true traffic light region with an affine moment invariant.

Shioyama, Tadayoshi; Wu, Haiyuan; Nakamura, Naoki; Kitawaki, Suguru

2002-09-01

171

Automatic Crack Length Measurements by the Electrical Potential Drop Method with Computer Control.  

National Technical Information Service (NTIS)

A method for automatic crack length measurements in fatigue crack propagation tests is described. Using a constant electric current through the specimen, the electric potential drop near the crack and a reference potential drop on the same specimen away f...

A. Burgers P. D. Kempen

1984-01-01

172

Quantum Correlations Induced by Local von Neumann Measurement  

NASA Astrophysics Data System (ADS)

We study the total quantum correlation, semiquantum correlation and joint quantum correlation induced by local von Neumann measurement in bipartite system. We analyze the properties of these quantum correlations and obtain analytical formula for pure states. The experimental witness for these quantum correlations is further provided and the significance of these quantum correlations is discussed in the context of local distinguishability of quantum states.

Zhao, Ming-Jing; Zhang, Ting-Gui; Li, Zong-Guo; Li-Jost, Xianqing; Fei, Shao-Ming; Zhong, De-Shou

2013-07-01

173

A New Family of Four-Valued Cross Correlation Between m-Sequences of Different Lengths  

Microsoft Academic Search

The cross-correlation function between m-sequences of period 2m - 1, where m = 6k, and m-sequences of shorter period 2m\\/2 - 1 is investigated. The first infinite family of pairs of m-sequences with four-valued cross correlation is constructed and the complete correlation distribution of this family is determined.

Geir Jarle Ness; Tor Helleseth

2007-01-01

174

Distributed fiber beat length, birefringence and differential group delay measurement using BOTDA technique  

NASA Astrophysics Data System (ADS)

A novel method for distributed fiber beat length, birefringence and differential group delay (DGD) measurement based on Brillouin optical time domain analysis (BOTDA) technique is proposed. The difference of local maximum and minimum Brillouin gain is determined by scanning input state of polarization (SOP) of pulsed probe wave to recover local beat length. The average beat length, birefringence and DGD measured on 100m SMF28 at 1550nm wavelength with 1m spatial resolution is 11.8m, 1.4×10-7 and 0.21ps respectively.

Xie, Shangran; Bao, Xiaoyi; Chen, Liang

2011-05-01

175

The Length of a Pestle: A Class Exercise in Measurement and Statistical Analysis.  

ERIC Educational Resources Information Center

|Outlines the simple exercise of measuring the length of an object as a concrete paradigm of the entire process of making chemical measurements and treating the resulting data. Discusses the procedure, significant figures, measurement error, spurious data, rejection of results, precision and accuracy, and student responses. (TW)|

O'Reilly, James E.

1986-01-01

176

Angular correlation measurements of207Bi  

NASA Astrophysics Data System (ADS)

Gamma-gamma angular correlation measurements of the 569·65 keV 1063·63 keV cascade in the decay of207Bi were carried out with two NaI (Tl) detectors of size (3?×3?) and (1·5?×1?). Graphical methods of Arns and Wiedenbeck (Phys. Rev. 111 (1958), 1631) were applied in determining the mixing ratio of gamma 1063·63 keV transition. The parametric plot was done by the method described by C. F. Colman (Nucl. Phys. 5 (1958), 495). The mixing ratio of gamma 1063·63 keV transition was thus found to be 10582_2005_Article_BF01604671_TeX2GIFE1.gif |? | = 0.036_{ - 0.064}^{ + 0.034} ..

Singh, G. P.; Mishra, R. K.; Singh, A. K.; Kumar, A.

1980-08-01

177

Normal Internal Organ Weight of Thai Adults Correlated to Body Length and Body Weight  

Microsoft Academic Search

Objective: Examine the relationship between the internal organ weight with body weight and body length. Material and Method: Analysis of data from 250 autopsies from the Ramathibodi Hospital from August 2003 to February 2005. The cases were from sudden unnatural death including accident, homicide and suicide and excluded decomposed bodies, fire related deaths and cases where medical treatment had been

Thamrong Chirachariyavej; Kritsa Ouyswat BSN; Seetala Sanggarnjanavanich DDS; Montip Tiensuwan; Vichan Peonim; Vorachai Sirikulchayanonta

2006-01-01

178

The importance of parameter variances, correlations lengths, and cross-correlations in reactive transport models: key considerations for assessing the need for microscale information  

SciTech Connect

A process-oriented modeling approach is implemented to examine the importance of parameter variances, correlation lengths, and especially cross-correlations in contaminant transport predictions over large scales. It is shown that the most important consideration is the correlation between flow rates and retardation processes (e.g., sorption, matrix diffusion) in the system. lf flow rates are negatively correlated with retardation factors in systems containing multiple flow pathways, then characterizing these negative correlation(s) may have more impact on reactive transport modeling than microscale information. Such negative correlations are expected in porous-media systems where permeability is negatively correlated with clay content and rock alteration (which are usually associated with increased sorption). Likewise, negative correlations are expected in fractured rocks where permeability is positively correlated with fracture apertures, which in turn are negatively correlated with sorption and matrix diffusion. Parameter variances and correlation lengths are also shown to have important effects on reactive transport predictions, but they are less important than parameter cross-correlations. Microscale information pertaining to contaminant transport has become more readily available as characterization methods and spectroscopic instrumentation have achieved lower detection limits, greater resolution, and better precision. Obtaining detailed mechanistic insights into contaminant-rock-water interactions is becoming a routine practice in characterizing reactive transport processes in groundwater systems (almost necessary for high-profile publications). Unfortunately, a quantitative link between microscale information and flow and transport parameter distributions or cross-correlations has not yet been established. One reason for this is that quantitative microscale information is difficult to obtain in complex, heterogeneous systems. So simple systems that lack the complexity and heterogeneity of real aquifer materials are often studied. Another is that instrumentation used to obtain microscale information often probes only one variable or family of variables at a time, so linkages to other variables must be inferred by indirect means from other lines of evidence. Despite these limitations, microscale information can be useful in the development and validation of reactive transport models. For example, knowledge of mineral phases that have strong affinities for contaminants can help in the development of cross-correlations between flow and sorption parameters via characterization of permeability and mineral distributions in aquifers. Likewise, microscale information on pore structures in low-permeability zones and contaminant penetration distances into these zones from higher-permeability zones (e.g., fractures) can provide valuable constraints on the representation of diffusive mass transfer processes between flowing porosity and secondary porosity. The prioritization of obtaining microscale information in any groundwater system can be informed by modeling exercises such as those conducted for this study.

Reimus, Paul W [Los Alamos National Laboratory

2010-12-08

179

Simple focal-length measurement technique with a circular Dammann grating  

NASA Astrophysics Data System (ADS)

A novel technique for focal-length measurements with a circular Dammann grating is presented. In the back focal plane of the lens under test, a one-order circular Dammann grating with limited aperture will produce double-humped radial rings. The separation between the two lobes varies with the displacement of the observed plane from the focal plane of the lens. By searching for the position at which the separation is minimal, the focal point of the lens can be located and hence the back focal length can be determined. Experimental results demonstrated that this method is efficient and can be used effectively for a quick check of focal length.

Zhao, Shuai; Fung Wen, Jacky; Sheun Chung, Po

2007-01-01

180

Slip Lengths on Hydrophobic and Hydrophilic Surfaces Measured by Quantum Dots  

NASA Astrophysics Data System (ADS)

We report measurements of slip length obtained from tracking of individual quantum dots (QDs) within a few hundred nanometers of a surface using evanescent wave illumination. The measurements are obtained at different shear rates on a hydrophilic (quartz) and a hydrophobic (OTS-coated quartz) surface forming the wall of a rectangular microchannel nominally 300 micron in height. The shear rate is obtained independently by molecular tagging velocimetry (MTV) measurement of the in-situ velocity profile across the 300 micron height of the microchannel. Results indicate a larger slip length for the hydrophobic surface.

Koochesfahani, Manoochehr; Pouya, Shahram; Lum, Chee; Snee, Preston; Bawendi, Moungi; Nocera, Daniel

2006-11-01

181

Stern potential and Debye length measurements in dilute ionic solutions with electrostatic force microscopy.  

PubMed

We demonstrate the ability to measure Stern potential and Debye length in dilute ionic solution with atomic force microscopy. We develop an analytic expression for the second harmonic force component of the capacitive force in an ionic solution from the linearized Poisson-Boltzmann equation. This allows us to calibrate the AFM tip potential and, further, obtain the Stern potential of sample surfaces. In addition, the measured capacitive force is independent of van der Waals and double layer forces, thus providing a more accurate measure of Debye length. PMID:24076615

Kumar, Bharat; Crittenden, Scott R

2013-09-27

182

Stern potential and Debye length measurements in dilute ionic solutions with electrostatic force microscopy  

NASA Astrophysics Data System (ADS)

We demonstrate the ability to measure Stern potential and Debye length in dilute ionic solution with atomic force microscopy. We develop an analytic expression for the second harmonic force component of the capacitive force in an ionic solution from the linearized Poisson-Boltzmann equation. This allows us to calibrate the AFM tip potential and, further, obtain the Stern potential of sample surfaces. In addition, the measured capacitive force is independent of van der Waals and double layer forces, thus providing a more accurate measure of Debye length.

Kumar, Bharat; Crittenden, Scott R.

2013-11-01

183

Influence of crack length on crack depth measurement by an alternating current potential drop technique  

NASA Astrophysics Data System (ADS)

An alternating current potential drop (ACPD) technique is used for sizing depth of surface cracks in metallic components. Crack depth estimations are prone to large deviations when ACPD measurements are made on very shallow and finite length cracks, especially in low conducting materials such as austenitic stainless steel (SS). Detailed studies have been carried out to investigate the influence of crack length and aspect ratio (length to depth) on depth estimation by performing measurements on electric discharge machined notches with the aspect ratio in the range of 1 to 40 in SS plates. In notches with finite length, an additional path for current to flow through the surface along the length is available causing the notch depths to be underestimated. The experimentally observed deviation in notch depth estimates is explained from a simple mathematical approach using the equivalent resistive circuit model based on the additional path available for the current to flow. A scheme is proposed to accurately measure the depth of cracks with finite lengths in SS components.

Raja, Manoj K.; Mahadevan, S.; Rao, B. P. C.; Behera, S. P.; Jayakumar, T.; Raj, Baldev

2010-10-01

184

PROSTATE CANCER STAGING: CORRELATION BETWEEN ULTRASOUND DETERMINED TUMOR CONTACT LENGTH AND PATHOLOGICALLY CONFIRMED EXTRAPROSTATIC EXTENSION  

Microsoft Academic Search

PurposeWe determine whether a new parameter, the amount of tumor in contact with the fibromuscular rim (capsule) of the prostate, correlates with extraprostatic extension, and ascertain whether estimating the new parameter using transrectal ultrasonography can predict extraprostatic extension.

OSAMU UKIMURA; PATRICIA TRONCOSO; EDILBERTO I. RAMIREZ; R. JOSEPH BABAIAN

1998-01-01

185

Measuring minority-carrier diffusion length using a Kelvin probe force microscope  

Microsoft Academic Search

A method based on Kelvin probe force microscopy for measuring minority-carrier diffusion length in semiconductors is described. The method is based on measuring the surface photovoltage between the tip of an atomic force microscope and the surface of an illuminated semiconductor junction. The photogenerated carriers diffuse to the junction and change the contact potential difference between the tip and the

R. Shikler; N. Fried; T. Meoded; Y. Rosenwaks

2000-01-01

186

Direct measurement of minority carriers diffusion length using Kelvin probe force microscopy  

Microsoft Academic Search

We report on the use of Kelvin force microscopy as a method for measuring very short minority carrier diffusion length in semiconductors. The method is based on measuring the surface photovoltage between the tip of an atomic force microscope and the surface of an illuminated semiconductor junction. The photogenerated carriers diffuse to the junction, and change the contact potential difference

T. Meoded; R. Shikler; N. Fried; Y. Rosenwaks

1999-01-01

187

Triplet repeat mutation length gains correlate with cell-type specific vulnerability in Huntington disease brain  

Microsoft Academic Search

Huntington disease is caused by the expansion of a CAG repeat encoding an extended glutamine tract in a protein called huntingtin. Here, we provide evidence supporting the hypothesis that somatic increases of mutation length play a role in the progressive nature and cell-selective aspects of HD pathogenesis. Results from micro-dissected tissue and individual laser-dissected cells obtained from human HD cases

Peggy F. Shelbourne; Christine Keller-McGandy; Wenya Linda Bi; Song-Ro Yoon; Louis Dubeau; Nicola J. Veitch; Jean Paul Vonsattel; Nancy S. Wexler; Norman Arnheim; Sarah J. Augood

2007-01-01

188

Search for a correlation between telomere length and severity of retinitis pigmentosa due to the dominant rhodopsin Pro23His mutation  

PubMed Central

Purpose Great variation exists in the age of onset of symptoms and the severity of disease at a given age in patients with retinitis pigmentosa (RP). The final pathway for this disease may involve apoptotic photoreceptor cell death. Telomere length is associated with biologic aging, senescence, and apoptosis. We evaluated whether the length of telomeres in leukocytes correlated with the severity of RP in patients with the Pro23His rhodopsin mutation who have shown marked heterogeneity in disease severity. Methods We evaluated 122 patients with the Pro23His rhodopsin mutation. The patients’ retinal function was stratified according to their 30-Hz cone electroretinogram (ERG). The length of telomeres in leukocytes was measured by the quantitative real time polymerase chain reaction (qRT–PCR) method in the 15 patients with the highest age-adjusted 30-Hz ERG amplitudes and in the 15 patients with the lowest amplitudes. Results Mean leukocyte telomere length was similar in the 15 patients with the highest cone ERG amplitudes (median: 0.40 units; interquartile range 0.36–0.56) and the 15 patients with the lowest cone amplitudes (median: 0.41 units; inter quartile range 0.34 ?0.64; p=0.95). Conclusions We found no evidence for an association between telomere length and the severity of RP as monitored by the cone ERG in patients with the Pro23His rhodopsin mutation.

McGee, Terri L.; Sandberg, Michael A.; Berson, Eliot L.; Asselbergs, Folkert W.; van der Harst, Pim; De Vivo, Immaculata; Dryja, Thaddeus P.

2009-01-01

189

EARLINET correlative measurements for CALIPSO: First intercomparison results  

Microsoft Academic Search

A strategy for European Aerosol Research Lidar Network (EARLINET) correlative measurements for Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) has been developed. These EARLINET correlative measurements started in June 2006 and are still in progress. Up to now, more than 4500 correlative files are available in the EARLINET database. Independent extinction and backscatter measurements carried out at high-performance EARLINET

Gelsomina Pappalardo; Ulla Wandinger; Lucia Mona; Anja Hiebsch; Ina Mattis; Aldo Amodeo; Albert Ansmann; Patric Seifert; Holger Linné; Arnoud Apituley; Lucas Alados Arboledas; Dimitris Balis; Anatoli Chaikovsky; Giuseppe D'Amico; Ferdinando De Tomasi; Volker Freudenthaler; Elina Giannakaki; Aldo Giunta; Ivan Grigorov; Marco Iarlori; Fabio Madonna; Rodanthi-Elizabeth Mamouri; Libera Nasti; Alexandros Papayannis; Aleksander Pietruczuk; Manuel Pujadas; Vincenzo Rizi; Francesc Rocadenbosch; Felicita Russo; Franziska Schnell; Nicola Spinelli; Xuan Wang; Matthias Wiegner

2010-01-01

190

A Hall effect transducer for measuring length changes in mammalian diaphragm.  

PubMed

When a conductor through which a current is flowing is brought into a magnetic field, the isopotential lines are distorted (E. H. Hall, 1879). When a constant current is made to flow through a Hall generator, the measured voltage perpendicular to the current flow can be made to vary by altering the distance between a permanent magnet and a Hall generator. A length transducer useful for measuring length changes in the diaphragm of a dog is made by connecting a commercially available Hall generator to a Plexiglas plate (5 X 10 X 3 mm, 0.5 g), and suturing the plate to the surface of the muscle. A permanent magnet (20 X 10 X 4 mm, 1.5 g) is attached to the diaphragm at a distance of 2 or 3 cm along the expected direction of length change. Fine wires from the terminals of the Hall generator are connected to an external constant-current source and to solid-state circuitry which provides amplification, linearization, and temperature compensation of the output signal. Model experiments indicate that the length measurements may be accurate within 5% if the distance between the magnet and Hall generator is greater than 5 mm. With this type of transducer measurements of segmental length changes in the diaphragm of an anesthetized dog have been successfully recorded. PMID:6618957

Peterson, C V; Otis, A B

1983-08-01

191

Measurement of the dechanneling length for high-energy negative pions  

NASA Astrophysics Data System (ADS)

We studied the dechanneling length of 150 GeV/c?- interacting with a short bent silicon crystal. Dechanneling length measures the rate and the strength of incoherent interactions of channeled particles in a crystal. The mechanism of dechanneling of negatively charged particles has been elucidated through simulation and experiment. It was found that the dechanneling length for negative particles is comparable to the nuclear dechanneling length for positive charges. Indeed, dechanneling of negative particles occurs as a result of incoherent interactions with the nuclei because the trajectories of such particles always intersect atomic planes, explaining the lower channeling efficiency for such particles. Obtained results can be useful for the design of crystals for manipulating high-energy negative particle beams through channeling.

Scandale, W.; Losito, R.; Bagli, E.; Bandiera, L.; Dalpiaz, P.; Fiorini, M.; Guidi, V.; Mazzolari, A.; Vincenzi, D.; Della Mea, G.; Vallazza, E.; Afonin, A. G.; Chesnokov, Yu. A.; Maisheev, V. A.; Yazynin, I. A.; Kovalenko, A. D.; Taratin, A. M.; Denisov, A. S.; Gavrikov, Yu. A.; Ivanov, Yu. M.; Lapina, L. P.; Skorobogatov, V. V.; Bolognini, D.; Hasan, S.; Prest, M.

2013-02-01

192

Bunch Length Measurements at the JLab FEL Using Coherent Transition and Synchrotron Radiation  

NASA Astrophysics Data System (ADS)

The JLab FEL is routinely operated with sub-picosecond bunches. The short bunch length is important for high gain of the FEL. Coherent transition radiation has been used for the bunch length measurements for many years. This diagnostic can be used only in the pulsed beam mode. It is our goal to run the FEL with CW beam and a 74.85 MHz micropulse repetition rate, which, with the 135 pC nominal bunch charge corresponds to the beam average current of 10 mA, Hence it is very desirable to have the possibility of making bunch length measurements when running CW beam with any micropulse frequency. We use a Fourier transform infrared (FTIR) interferometer, which is essentially a Michelson interferometer, to measure the spectrum of the coherent synchrotron radiation generated in the last dipole of the magnetic bunch compressor upstream of the FEL wiggler. This noninvasive diagnostic provides bunch length measurements for CW beam operation at any micropulse frequency. We also compare the measurements made with the help of the FTIR interferometer with data obtained using the Martin-Puplett interferometer. Results of the two diagnostics agree within 15 %. Here we present a description of the experimental setup, data evaluation procedure and results of the beam measurements.

Evtushenko, P.; Coleman, J.; Jordan, K.; Klopf, J. Michael; Neil, G.; Williams, G. P.

2006-11-01

193

Longitudinal-to-Transverse Mapping for Femtosecond Electron Bunch Length Measurement  

SciTech Connect

A longitudinal-to-transverse mapping technique is proposed to measure the length and temporal profile of ultrashort electron bunches. In this scheme a special chicane and a radio-frequency deflecting cavity are used to transform the beam's longitudinal distribution into angular distribution which is further converted to transverse distribution after a parallel-to-point imaging beam line. With this technique, the temporal profile of the electron beam is exactly mapped to the transverse profile. This makes it possible to measure ultrashort electron bunch length with a resolution well beyond 1 femtosecond.

Xiang, Dao; Ding, Yuantao; /SLAC

2010-08-25

194

Wound Botulism in Injection Drug Users: Time to Antitoxin Correlates with Intensive Care Unit Length of Stay  

PubMed Central

Objectives: We sought to identify factors associated with need for mechanical ventilation (MV), length of intensive care unit (ICU) stay, length of hospital stay, and poor outcome in injection drug users (IDUs) with wound botulism (WB). Methods: This is a retrospective review of WB patients admitted between 1991–2005. IDUs were included if they had symptoms of WB and diagnostic confirmation. Primary outcome variables were the need for MV, length of ICU stay, length of hospital stay, hospital-related complications, and death. Results: Twenty-nine patients met inclusion criteria. Twenty-two (76%) admitted to heroin use only and seven (24%) admitted to heroin and methamphetamine use. Chief complaints on initial presentation included visual changes, 13 (45%); weakness, nine (31%); and difficulty swallowing, seven (24%). Skin wounds were documented in 22 (76%). Twenty-one (72%) patients underwent mechanical ventilation (MV). Antitoxin (AT) was administered to 26 (90%) patients but only two received antitoxin in the emergency department (ED). The time from ED presentation to AT administration was associated with increased length of ICU stay (Regression coefficient = 2.5; 95% CI 0.45, 4.5). The time from ED presentation to wound drainage was also associated with increased length of ICU stay (Regression coefficient = 13.7; 95% CI = 2.3, 25.2). There was no relationship between time to antibiotic administration and length of ICU stay. Conclusion: MV and prolonged ICU stays are common in patients identified with WB. Early AT administration and wound drainage are recommended as these measures may decrease ICU length of stay.

Offerman, Steven R.; Schaefer, Melissa; Thundiyil, Joseph G.; Cook, Matthew D.; Holmes, James F.

2009-01-01

195

First working group meeting on the minority carrier diffusion length/lifetime measurement: Results of the round robin lifetime/diffusion length tests  

SciTech Connect

As was noted in the cover letter that accompanied the samples, the eleven bare silicon samples were from various manufacturers. Table I lists the codes for the samples and the manufacturer of each sample. It also notes if the sample was single or poly-crystalline. The samples had been polished on one side before being sent out for measurements, but no further processing was done. The participants of the study were asked to measure either the lifetime or diffusion length of each of the samples using their standard procedure. Table II shows the experimental conditions used by the groups who measured diffusion length. All the diffusion length measurements were performed using the Surface Photovoltage method (SPV). Table M shows the experimental conditions for the lifetime measurements. All the lifetime measurements were made using the Photoconductance Decay method (PCD) under low level injection. These tables show the diameter of the spot size used during the measurement (the effective sampling area), the locations where measurements were taken, and the number of measurements taken at each location. Table N shows the results of the measurements. The table is divided into diffusion length and lifetime measurements for each sample. The values listed are the average values reported by each group. One of the immediate artifacts seen in the data is the large variation in the lifetime measurements. The values from MIT and Mobil are generally close. However, the measurements from NCSU are typically an order of magnitude lower.

Cudzinovic, M.; Sopori, B. [comp.

1995-11-01

196

Research on all fiber beat length measurement system for polarization-maintaining fibers  

NASA Astrophysics Data System (ADS)

Polarization-maintaining fiber (PMF) has attracted great attentions not only due to its ability to realize coherent optic communication with ultrahigh-capacity, but also because it can be widely employed in high-precise fiber-optic sensors and optic information processors, e.g., fiber-optic gyroscope and fiber-optic amperemeter. Distinct with common monomode optic fibers, additional birefringence is introduced in the PMF, minimizing the effect of mode coupling between two orthogonal polarization modes in optic fibers. Thus, light polarization can be maintained after long distance transmission in the PMF. However, beat-length, which reflects the characteristic of induced birefringence and evaluates the ability of polarization maintaining, is one of the most important parameters for PMF. Accurate measurement of PMF beat length becomes more and more important along with the expanding of its application field. The uniqueness of the measurement results determines the identity of PMF fabrication and the resolution of fiber-optic sensors. The existing measurement methods for PMF beat length are introduced first. Most testing setups are established by several individual components, which lead to complicated setup, inconvenient testing, and unsteady measurement. In this paper, a novel all fiber beat length measurement system is presented, where optic source, integrated optic modulator, stress apply structure, polarization detector, and polarization indicator of output light are included. The configuration and working principle of the whole system, and the designing and realization of each components, are addressed in the paper. Furthermore, the influence on measurement results by the relative direction between applied stress and principal axis of the optic fiber is analyzed. Moreover, optimized designs, including polarized light incidence, pressure apply, and precise movement systems, are performed, which ensure the identical pressure apply direction in the moving process. Finally, measurement of PMF samples is carried out on experimental setup. In comparison with the other existing system, due to its all fiber light incidence structure, the novel beat length measurement system represents great stability and high reliability.

Peng, Li; Feng, Lishuang; Zhang, Xiaoqing; Hong, Lingfei

2010-12-01

197

Improvement in the measurement of focal length using spot patterns and spherical aberration.  

PubMed

Using an optical setup that includes a square array of 3×3 holes, we used nine meridional rays to measure the effective focal length of a lens. We observed the selected meridional rays as a spot pattern on a diffuse screen. First, we generated a regular square spot pattern (reference pattern) without a lens to test, and then we generated two spot patterns in two different axial positions when the lens being tested refracts the rays. By selecting two sets of four rays of each spot pattern, we were able to measure the difference of the longitudinal (primary) spherical aberration in two positions. With this difference we were able to improve the calculation of the effective focal length. To determine the method's precision, we first simulated the relative error in the effective focal length considering the error in the measurement of the ray heights. Then we determined the experimental relative error by means of the standard deviation of the focal lengths obtained for each spot (in the image of reference and for the images at the two different locations) for both sets of four spots. The experimental results agree very well with the simulation. The error analysis allows us to establish under what conditions it is possible to obtain relative errors of less than 1% in the effective focal length. PMID:23938404

Mejía, Yobani

2013-08-10

198

Measurement of bunch length in Indus-1 storage ring using fast photodiode  

NASA Astrophysics Data System (ADS)

The length of electron bunches in a storage ring is an important parameter for both synchrotron radiation users and accelerator physicists. Several methods are used for measurements of bunch length using electronic and optical instruments. We have measured temporal profile of synchrotron radiation emitted from dipole magnet of Indus-1 by using fast photodiode. Bunch length is calculated by assuming gaussian profile for the particles inside bunch. The results show that bunch length is increasing with the decrease of gap voltage of RF cavity. These measurements were carried out at low beam current; at high voltage results are in close agreement with theory and the values estimated using ZAP code. In the second experiment, the results show that bunch length increases with the increase of beam current inside the bunch, and above threshold current, it follows Chao-Gareyte scaling law. The longitudinal broadband impedance for Indus-1 SRS was estimated using Keil-Schnell criterion and results were compared with theoretical estimated values using ZAP code.

Garg, Akash Deep; Nathwani, R. K.; Holikatti, A. C.; Kumar Karnewar, Akhilesh; Tyagi, Y.; Yadav, S.; Puntambekar, T. A.; Navathe, C. P.

2012-11-01

199

Measurement of bunch length in Indus-1 storage ring using fast photodiode.  

PubMed

The length of electron bunches in a storage ring is an important parameter for both synchrotron radiation users and accelerator physicists. Several methods are used for measurements of bunch length using electronic and optical instruments. We have measured temporal profile of synchrotron radiation emitted from dipole magnet of Indus-1 by using fast photodiode. Bunch length is calculated by assuming gaussian profile for the particles inside bunch. The results show that bunch length is increasing with the decrease of gap voltage of RF cavity. These measurements were carried out at low beam current; at high voltage results are in close agreement with theory and the values estimated using ZAP code. In the second experiment, the results show that bunch length increases with the increase of beam current inside the bunch, and above threshold current, it follows Chao-Gareyte scaling law. The longitudinal broadband impedance for Indus-1 SRS was estimated using Keil-Schnell criterion and results were compared with theoretical estimated values using ZAP code. PMID:23206055

Garg, Akash Deep; Nathwani, R K; Holikatti, A C; Karnewar, Akhilesh Kumar; Tyagi, Y; Yadav, S; Puntambekar, T A; Navathe, C P

2012-11-01

200

Measurement of bunch length in Indus-1 storage ring using fast photodiode  

SciTech Connect

The length of electron bunches in a storage ring is an important parameter for both synchrotron radiation users and accelerator physicists. Several methods are used for measurements of bunch length using electronic and optical instruments. We have measured temporal profile of synchrotron radiation emitted from dipole magnet of Indus-1 by using fast photodiode. Bunch length is calculated by assuming gaussian profile for the particles inside bunch. The results show that bunch length is increasing with the decrease of gap voltage of RF cavity. These measurements were carried out at low beam current; at high voltage results are in close agreement with theory and the values estimated using ZAP code. In the second experiment, the results show that bunch length increases with the increase of beam current inside the bunch, and above threshold current, it follows Chao-Gareyte scaling law. The longitudinal broadband impedance for Indus-1 SRS was estimated using Keil-Schnell criterion and results were compared with theoretical estimated values using ZAP code.

Garg, Akash Deep; Nathwani, R. K.; Holikatti, A. C.; Kumar Karnewar, Akhilesh; Tyagi, Y.; Yadav, S.; Puntambekar, T. A.; Navathe, C. P. [Beam Diagnostics Section, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

2012-11-15

201

CTR Bunch Length Measurement of Monoenergetic and Maxwellian Electron Beams from Laser Plasma Cathode  

SciTech Connect

Recently, several plasma cathodes at universities and institutes can generate a monoenergetic electron beam. LBL measured the bunch length by the CTR (Coherent Transition Radiation) interferometer to determine it as about 50 fs (FWHM). We are trying to carry out a single-shot measurement of the bunch length by a infrared polychromator. As the first step forward it, we measured the CTR spectra emitted at a 300microm-thick Ti foil by the electron beams from our plasma cathode. The laser parameters are 12 TW, 50fs, 3x1019W/cm2. He gas-jet is used and the electron density is 6x1019cm-3. By using the liquid He bolometer and several optical low-pass filter, we measured the spectra of the CTR. We can clearly classify the difference of the spectrum and bunch length for the monoenergetic and Maxwellian beams. The numerical analysis of the bunch elongation due to the energy spread confirms the experimental results. The bunch length of the monoenergetic beam is less than 100 fs at FWHM with about 10 pC per bunch, which is consistent with the PIC simulation. The next single-shot measurement with the FIR (Far-Ingfra-Red) polychomator and application to a pump-and-probe experiment for radiation chemsitry are also discussed.

Uesaka, Mitsuru; Maekawa, Akira; Tsujii, Ryosuke; Kinoshita, Kennichi; Atsushi, Yamazaki; Kobayashi, Kazuyuki; Shibata, Yukio; Kondo, Yasuhiro [Nuclear Professional School, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Ohkubo, Takeru [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma (Japan); Hosokai, Tomonao [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Zhidkov, Alexei [Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa (Japan); Takahashi, Toshiharu [Kyoto University Research Reactor Institute, 2 Asahiro-nishi, Kumatori, Sennan, Osaka (Japan)

2006-11-27

202

Length variation in a specific region of the period gene correlates with differences in pupal diapause incidence in the flesh fly, Sarcophaga bullata  

Microsoft Academic Search

We report differences in the length of a specific region of the circadian clock gene period (per) that correlate with different capacities for pupal diapause in the flesh fly, Sarcophaga bullata. The conspicuous difference is located in a region we refer to as the putative C-terminal photoperiodic (CP) region. The length of the CP region correlates inversely with the incidence

Bing Han; David L. Denlinger

2009-01-01

203

Channel length scaling in graphene field-effect transistors studied with pulsed current-voltage measurements.  

PubMed

We investigate current saturation at short channel lengths in graphene field-effect transistors (GFETs). Saturation is necessary to achieve low-output conductance required for device power gain. Dual-channel pulsed current-voltage measurements are performed to eliminate the significant effects of trapped charge in the gate dielectric, a problem common to all oxide-based dielectric films on graphene. With pulsed measurements, graphene transistors with channel lengths as small as 130 nm achieve output conductance as low as 0.3 mS/?m in saturation. The transconductance of the devices is independent of channel length, consistent with a velocity saturation model of high-field transport. Saturation velocities have a density dependence consistent with diffusive transport limited by optical phonon emission. PMID:21271736

Meric, Inanc; Dean, Cory R; Young, Andrea F; Baklitskaya, Natalia; Tremblay, Noah J; Nuckolls, Colin; Kim, Philip; Shepard, Kenneth L

2011-01-27

204

A new route for length measurement by phase-shifting interferometry  

NASA Astrophysics Data System (ADS)

By the mathematic models of flexible hinge, the accurate relationship between the phase-shifting and pressure acting on the hinge is deduced and verified by experimental results. Through the optimization of the geometric parameter of flexible hinge, a phase-shifting generator is developed to determine the length of an object precisely by interferometry. The experiments show that the triple phase-shifting produced using this generator is up to 1 ?m. With this generator, an example for the application in length measurement is introduced. The result shows the length uncertainty is 0.5 nm when the temperature uncertainty is limited in 2 mK. This paper provides a novel technique to measure the dimension of an object, especially to the diameter of a silicon sphere for Avogadro constant project.

Luo, ZhiYong; Li, ZhangHong

2012-04-01

205

Agreement and relationship between ultrasonic and partial coherence interferometry measurements of axial length and anterior chamber depth  

PubMed Central

Purpose To find the relationship between axial length (AL) and anterior chamber depth (ACD) measurements, using partial coherence interferometry (PCI) and A-scan ultrasonography (US). Setting National Eye Hospital, Cairo, Egypt. Method Retrieving and comparing biometric data from the files of 163 consecutive patients seeking cataract extraction by PCI (IOLMaster) and US (Sonomed). Results AL measured using US range from 20.93 to 33.17 mm (mean ± SD = 24.45 ± 2.73 mm). AL measured by PCI range from 20.90 to 33.27 mm (24.05 ± 2.76 mm). The range of ACD measured by US was 2.09 to 4.48 mm (3.32 ± 0.46 mm). The range of ACD measured by PCI was 2.15 to 4.29 mm (3.31 ± 0.45 mm). There is very high agreement between both methods; the intraclass correlation coefficient = 0.999 for AL, and 0.966 for ACD measurements. A linear regression model of two formulae fits the AL values (one for eyes longer than 29 mm, and the other for the shorter eyes), with no significant departure from linearity (P > 0.1). One formula fits the ACD values with significant departure from linearity (P < 0.05). Conclusion Both US and PCI methods for measurements of AL and ACD are highly correlated. Therefore, the value of AL measured by one method can be predicted, with high accuracy, from the other method.

Wissa, Amany R; Wahba, Sherein S; Roshdy, Maged M

2012-01-01

206

Radial correlation reflectometry measurements on the JET tokamak  

NASA Astrophysics Data System (ADS)

Fluctuations and turbulence are believed to play an important role in anomalous transport of heat and particles in magnetic fusion devices. It is of vital importance to characterize transport mechanism in order to understand and control it. In correlation reflectometry (CR), two microwave beams with different frequencies are launched into the plasma from which the turbulence correlation length, Lr, and the density fluctuation level, 0.7exn / n n.- 0.7exn can be deduced; quantities that are important for the study of plasma turbulence and transport. In this paper, some results of Lr obtained with the four X-mode CR systems installed at Joint European Torus (JET) are reported. Experimentally, it was observed that Lr increases from the plasma edge to the plasma core. Also, Lr decreases inside the Internal Transport Barriers (ITB) [1]. The results obtained at JET agree quiet well with the Lr dependence measured in other tokamak machines. [1] - A.C.A. Figueiredo, et.al., in the 34^th EPS Conference on Plasma Physics, Warsaw, Poland, 2-7 July, (2007).

Fonseca, A.; Alper, B.; Budny, R.; Cupido, L.; Fessey, J.; Figueiredo, A.; Hacquin, S.; Manso, M. E.; Mazzucato, E.; Meneses, L.; Sirinelli, A.; Walsh, M.

2007-11-01

207

Influence of crack length on crack depth measurement by an alternating current potential drop technique  

Microsoft Academic Search

An alternating current potential drop (ACPD) technique is used for sizing depth of surface cracks in metallic components. Crack depth estimations are prone to large deviations when ACPD measurements are made on very shallow and finite length cracks, especially in low conducting materials such as austenitic stainless steel (SS). Detailed studies have been carried out to investigate the influence of

Manoj K. Raja; S. Mahadevan; B. P. C. Rao; S. P. Behera; T. Jayakumar; Baldev Raj

2010-01-01

208

Sonographic Measurement of Cervical Length ad Fetal Fibronectin Testing in Threatened Preterm Labor  

Microsoft Academic Search

Objective In women presenting with threatened preterm labor, both fetal fibronectin and sonographic measure- ment of cervical length have been shown to distinguish between true and false labor. The aim of this study was to determine whether the combination of both tests provides a better prediction than the individual tests alone. Methods We examined 195 women with singleton preg- nancies

E. TSOI; S. AKMAL; L. GEERTS; B. JEFFERY; K. H. NICOLAIDES

2006-01-01

209

Length dependence of critical measures in single-walled carbon nanotubes  

Microsoft Academic Search

This paper presents an investigation on the buckling behaviour of single-walled carbon nanotubes under various loading conditions (compression, bending and torsion) and unveils several aspects concerning the dependence of critical measures (axial strain, bending curvature and twisting angle) on the nanotube length. The buckling results are obtained by means of an atomistic-scale generalized beam theory (GBT) that incorporates local deformation

N. Silvestre

2008-01-01

210

A model for the tropospheric excess path length of radio waves from surface meteorological measurements  

Microsoft Academic Search

Two models are given for predicting of the excess path length of radio waves from ground-based measurements of pressure, temperature, and humidity, at zenith and at a given apparent elevation angle. The models use the same formulation for the hydrostatic component of the excess path, but use different methods for the wet component. For the hydrostatic component, the models provide

H. Berrada Baby; P. Gole; J. Lavergnat

1988-01-01

211

The Effect of Wire Length and Separation on X-Array Hot-Wire Anemometer Measurements  

Microsoft Academic Search

This paper describes a simple method for the calculation of errors due to the finite length and separation of X-array hot-wire anemometers. Results of computations for a typical wire array are presented for total and spectral turbulence measurements. Although the actual errors are slightly underestimated due to the simplifying assumptions used to reduce the computational effort, it is found that

Klaus Bremhorst

1972-01-01

212

Measuring spin correlations in optical lattices  

NASA Astrophysics Data System (ADS)

The study of ultracold atoms in optical lattices has produced several groundbreaking results. A major, but presently unrealized goal, is to study quantum magnetism using atoms in optical lattices. We suggest three different experimental methods for probing both short- and long-range spin correlations of atoms in optical lattices. The first method involves an adiabatic doubling of the periodicity of the underlying lattice to probe neighboring singlet (triplet) correlations for fermions (bosons) by the occupation of the resulting vibrational ground state. The second method utilizes a time-dependent superlattice potential to generate spin-dependent transport by any number of prescribed lattice sites, and probes correlations by the resulting number of doubly occupied sites. The third method relies on the difference in tunneling times for the vibrational ground state and the first excited state. Correct timing then allows for the spin correlations to be fingerprinted. For experimentally relevant parameters, we demonstrate how all three methods yield large signatures of antiferromagnetic correlations of strongly repulsive fermionic atoms in a single shot of the experiment.

Pedersen, K. G. L.; Andersen, B. M.; Bruun, G. M.; Syljuåsen, O. F.; Sørensen, A. S.

2012-02-01

213

Accuracy and reliability of length measurements on three-dimensional computed tomography using open-source OsiriX software.  

PubMed

There is a growing interest in three-dimensional computed tomography (3D-CT) as a research tool for the study of bone, joint anatomy, and kinematics. However, when CT data are processed and handled manually using image processing programs to yield 3D image and coordinate value, systematic and random errors should be validated. We evaluated the accuracy and reliability of length measurement on CT with OsiriX software. 3D-CT scans were made of 14 frozen pig knees with five transosseous holes in the metaphyseal portion of femur. The lengths between tunnel orifices were measured using Mitutoyo Digimatic digital calipers to establish the gold standard, and with the OsiriX program in 3D multi-planar reformatting mode for comparison. All measurements were recorded by a principal (replicate 1, trial 1) and a secondary observer (replicate 2, trial 1) and were repeated once by each observer (trial 2). The mean differences between OsiriX and real measurements were less than 0.1 mm in both replicates, and maximum differences were less than 0.3 mm. There were no significant differences between the replicates and real measurements (p=0.544 and 0.622 for replicates 1 and 2, respectively). The intraclass correlation coefficients (ICC) were very high between trials and between replicates (ICC=0.998 and 0.999, respectively). For kinematic analysis of the knees, length measurements on 3D-CT using OsiriX program can be used as alternatives to real measurements with less than 0.3-mm accuracy and very high reliability. PMID:22270788

Kim, Gihyeon; Jung, Ho-Joong; Lee, Han-Jun; Lee, Jae-Sung; Koo, Seungbum; Chang, Seung-Hwan

2012-08-01

214

Beam size and bunch length measurements at the Anka storage ring  

Microsoft Academic Search

ANKA is an electron storage ring working at a nominal energy of 2.5 GeV. The beam is injected at 500 MeV into the storage ring and ramped to the final energy. The beam size and bunch length have been measured in the range from 500 MeV to 2.5 GeV. The beam size measurements were performed with two synchrotron light monitors,

F. Perez; I. Birkel; E. Huttel; A. S. Moller; M. Pont

2003-01-01

215

Reliability and validity of the partial coherence interferometry for measurement of ocular axial length in children  

Microsoft Academic Search

PurposeTo assess the validity and repeatability of partial coherence interferometry (IOLMaster) and A-scan ultrasound measurement of axial length (AL) in children.MethodsA prospective comparison of AL measurement made by the IOLMaster optical instrument (Carl Zeiss) and ultrasound A-scan (Alcon) was performed. A total of 20 children (11 male, nine female) were recruited into the study; the mean age of the sample

H M Hussin; P G D Spry; M A Majid; P Gouws

2006-01-01

216

Highly Precise Eye Length Measurements in Children Aged 3 Through 12 Years  

Microsoft Academic Search

Objective: To determine the feasibility, reliability, and validity of using partial coherence interferometry, a non- contact method that detects interference patterns from various layers of the eye, to measure axial length in young children. Methods: The right eye of 64 subjects (mean age, 8.4 y; age range, 3.4-12.9 y; best-corrected visual acuity20\\/ 30) was measured. Subjects fixated monocularly on the

Graham E. Quinn; Ellie L. Francis; Karen S. Nipper; D. Ian Flitcroft; Gui-shuang Ying; Renee C. Rees; Gregor F. Schmid; Maureen G. Maguire; Richard A. Stone

217

High-frequency noise measurements on MOSFETs with channel-lengths in sub-100 nm regime  

Microsoft Academic Search

High-Frequency signal and noise measurements on 40 nm, 80 nm, and 110 nm, gate-length MOS transistors are performed. On-wafer measurements of S-parameters up to 18 GHz yield an accurate small-signal RF device model with gm in excess of 1000 mS\\/mm. Noise contributions due to gate resistance, substrate resistance, source and drain resistances, substrate current and induced-gate noise are found to

Pradeep R. Patalay; R. P. Jindal; Hisashi Shichijo; S. Martin; Fan-Chi Hou; Django Trombley

2009-01-01

218

Pulsed ion beam measurement of defect diffusion lengths in irradiated solids  

NASA Astrophysics Data System (ADS)

Radiation-generated point defects in solids often experience dynamic annealing—diffusion and interaction processes after the thermalization of collision cascades. The length scale of dynamic annealing can be described in terms of the characteristic defect diffusion length (Ld). Here, we propose to measure Ld by a pulsed beam method. Our approach is based on the observation of enhanced defect production when, for individual ion pulses, the average separation between adjacent damage regions is smaller than Ld. We obtain a value for Ld of ˜30 nm for float-zone Si crystals bombarded at room temperature with 500 keV Ar ions.

Charnvanichborikarn, S.; Myers, M. T.; Shao, L.; Kucheyev, S. O.

2013-04-01

219

Infrared Spectroscope for Electron Bunch-length Measurement: Heat Sensor Parameters Analysis  

SciTech Connect

The Linac Coherent Light Source (LCLS) is used for many experiments. Taking advantage of the free electron laser (FEL) process, scientists of various fields perform experiments of all kind. Some for example study protein folding; other experiments are more interested in the way electrons interact with the molecules before they are destroyed. These experiments among many others have very little information about the electrons x-ray produced by the FEL, except that the FEL is using bunches less than 10 femtoseconds long. To be able to interpret the data collected from those experiments, more accurate information is needed about the electron's bunch-length. Existing bunch length measurement techniques are not suitable for the measurement of such small time scales. Hence the need to design a device that will provide more precise information about the electron bunch length. This paper investigates the use of a pyreoelectric heat sensor that has a sensitivity of about 1.34 micro amps per watt for the single cell detector. Such sensitivity, added to the fact that the detector is an array sensor, makes the detector studied the primary candidate to be integrated to an infrared spectrometer designed to better measure the LCLS electron bunch length.

Domgmo-Momo, Gilles; /Towson U. /SLAC

2012-09-05

220

Reliability and Short-Term Intra-Individual Variability of Telomere Length Measurement Using Monochrome Multiplexing Quantitative PCR  

Microsoft Academic Search

BackgroundStudies examining the association between telomere length and cancer risk have often relied on measurement of telomere length from a single blood draw using a real-time PCR technique. We examined the reliability of telomere length measurement using sequential samples collected over a 9-month period.Methods and FindingsRelative telomere length in peripheral blood was estimated using a single tube monochrome multiplex quantitative

Sangmi Kim; Dale P. Sandler; Gleta Carswell; Clarice R. Weinberg; Jack A. Taylor; Arthur J. Lustig

2011-01-01

221

Urinary continence following laparoscopic radical prostatectomy: Association with postoperative membranous urethral length measured using real-time intraoperative transrectal ultrasonography  

PubMed Central

Urinary incontinence is a major complication following radical prostatectomy. The aim of the present study was to assess the association between urinary continence following laparoscopic radical prostatectomy (LRP) and various factors measured using real-time intraoperative transrectal ultrasonography (TRUS). Patients (n=53) with localized prostate cancer underwent LRP in combination with real-time intraoperative TRUS navigation and were evaluated for urinary continence for more than 6 months following LRP. Prostate size, membranous urethral length (MUL) and bladder-urethra angle were measured using real-time intraoperative TRUS immediately before and after surgery. Urinary continence was regained by 4, 15 and 27 patients 1, 3 and 6 months after LRP, respectively. Longer postoperative MUL was significantly correlated with recovery of urinary continence 1, 3 and 6 months after LRP. In addition, an increase in difference between preoperative and postoperative MUL was also associated with superior continence. No correlation was observed between postoperative MUL and the rate of tumor-positive surgical margins. Larger prostate volume was correlated to postoperative continence 6 months after surgery. Shorter operation time and less blood loss resulted in postoperative urinary continence 1 month after LRP. Preoperative MUL, bladder-urethra angle, age and body mass index had no correlation with urinary continence. Postoperative MUL was the most significant factor for early recovery of urinary continence following LRP. These results indicate that preservation of longer urethra during surgery may be recommended without tumor-positive surgical margins.

MIZUTANI, YOICHI; UEHARA, HIROSHI; FUJISUE, YUTAKA; TAKAGI, SHIZUKO; NISHIDA, TAKESHI; INAMOTO, TERUO; UBAI, TAKANOBU; NOMI, HAYAHITO; KATSUOKA, YOJI; AZUMA, HARUHITO

2012-01-01

222

Conformation, Length, and Speed Measurements of Electrodynamically Stretched DNA in Nanochannels  

PubMed Central

A method is presented to rapidly and precisely measure the conformation, length, speed, and fluorescence intensity of single DNA molecules constrained by a nanochannel. DNA molecules were driven electrophoretically from a nanoslit into a nanochannel to confine and dynamically elongate them beyond their equilibrium length for repeated detection via laser-induced fluorescence spectroscopy. A single-molecule analysis algorithm was developed to analytically model bursts of fluorescence and determine the folding conformation of each stretched molecule. This technique achieved a molecular length resolution of 114 nm and an analysis time of around 20 ms per molecule, which enabled the sensitive investigation of several aspects of the physical behavior of DNA in a nanochannel. ?-bacteriophage DNA was used to study the dependence of stretching on the applied device bias, the effect of conformation on speed, and the amount of DNA fragmentation in the device. A mixture of ?-bacteriophage with the fragments of its own HindIII digest, a standard DNA ladder, was sized by length as well as by fluorescence intensity, which also allowed the characterization of DNA speed in a nanochannel as a function of length over two and a half orders of magnitude.

Reccius, Christian H.; Stavis, Samuel M.; Mannion, John T.; Walker, Larry P.; Craighead, H. G.

2008-01-01

223

A strong correlation exists between the distribution of retinal ganglion cells and nose length in the dog.  

PubMed

The domestic dog, CANIS LUPUS FAMILIARIS, is a subspecies of the gray wolf, CANIS LUPUS, with almost identical mitochondrial DNA. The dog is the most diverse species on earth, with skull length varying between 7 and 28 cm whereas the wolf skull is around 30 cm long. However, eye size in dogs does not appear to vary as much. For example, small dogs such as the chihuahua appear to have very large eyes in proportion to the skull. Our aim was to examine eye size and retinal cell numbers and distribution to determine whether the dog eye exhibits as much variation as the skull. We found a correlation between eye radius and skull dimensions. However, the most surprising finding was that the distribution of ganglion cells in the eye varied tremendously from a horizontally aligned visual streak of fairly even density across the retina (as seen in the wolf) to a strong area centralis with virtually no streak (for example, as observed in a pug from the current series). This variation in ganglion cell density within a single species is quite unique. Intriguingly, the ratio of peak ganglion cell density in the area centralis to visual streak was highly negatively correlated with skull length (r = -0.795, n = 22) and positively correlated with cephalic index (r = 0.687, n = 22). The orientation of eyelid aperture was also correlated with cephalic index (r = 0.648, n = 22). Therefore, the genetic manipulation of selective breeding, which has produced an abnormal shortening of the skull and eyelids with less lateral apertures, has also produced a considerably more pronounced area centralis in the dog. PMID:14673195

McGreevy, Paul; Grassi, Tanya D; Harman, Alison M

2004-01-01

224

TRINAT: measuring ?-decay correlations with laser-trapped atoms  

NASA Astrophysics Data System (ADS)

TRIUMF's neutral atom trap for ? decay (TRINAT) has been used to measure the most accurate ?-? correlation. Plans include improving that measurement, and also carrying out a full program of spin-polarized ? decay correlation measurements complementary to the decay of the neutron

Behr, J. A.; Gorelov, A.; Jackson, K. P.; Pearson, M. R.; Anholm, M.; Kong, T.; Behling, R. S.; Fenker, B.; Melconian, D.; Ashery, D.; Gwinner, G.

2013-10-01

225

Is Socioeconomic Status Associated With Biological Aging as Measured by Telomere Length?  

PubMed Central

It has been hypothesized that one way in which lower socioeconomic status (SES) affects health is by increasing the rate of biological aging. A widely used marker of biological aging is telomere length. Telomeres are structures at the ends of chromosomes that erode with increasing cell proliferation and genetic damage. We aimed to identify, through systematic review and meta-analysis, whether lower SES (greater deprivation) is associated with shorter telomeres. Thirty-one articles, including 29 study populations, were identified. We conducted 3 meta-analyses to compare the telomere lengths of persons of high and low SES with regard to contemporaneous SES (12 study populations from 10 individual articles), education (15 study populations from 14 articles), and childhood SES (2 study populations from 2 articles). For education, there was a significant difference in telomere length between persons of high and low SES in a random-effects model (standardized mean difference (SMD) = 0.060, 95% confidence interval (CI): 0.002, 0.118; P = 0.042), although a range of sensitivity analyses weakened this association. There was no evidence for an association between telomere length and contemporaneous SES (SMD = 0.104, 95% CI: ?0.027, 0.236; P = 0.119) or childhood SES (SMD = ?0.037, 95% CI: ?0.143, 0.069; P = 0.491). These results suggest weak evidence for an association between SES (as measured by education) and biological aging (as measured by telomere length), although there was a lack of consistent findings across the SES measures investigated here.

Robertson, Tony; Batty, G. David; Der, Geoff; Fenton, Candida; Shiels, Paul G.; Benzeval, Michaela

2013-01-01

226

Measurement of the transverse spin correlations in the decay Z ? ? + ? ?  

Microsoft Academic Search

For ? leptons produced in e+e? ? ?+?? interactions there are, in addition to the longitudinal spin correlations, two independent transverse spin correlations associated with the transverse (within the production plane) and normal (to the production plane) polarization components. A measurement of the transverse-transverse and transverse-normal ? spin correlations in the decay Z ? ?+??, CTT and CTN, is presented

R. Barate; D. Buskulic; D. Decamp; P. Ghez; C Goy; J.-P Lees; A. Lucotte; M.-N Minard; J.-Y Nief; B. Pietrzyk; M. P Casado; M. Chmeissani; P. Comas; J. M Crespo; M. Delfino; E. Fernandez; M. Fernandez-Bosman; Ll. Garrido; A. Juste; M. Martinez; R. Miquel; Ll. M Mir; S. Orteu; C. Padilla; I. C Park; A. Pascual; J. A Perlas; I. Riu; F. Sanchez; F. Teubert; A. Colaleo; D. Creanza; M de Palma; G. Gelao; G. Iaselli; G. Maggi; M. Maggi; N. Marinelli; S. Nuzzo; A. Ranieri; G. Raso; F. Ruggieri; G. Selvaggi; L. Silvestris; P. Tempesta; A. Tricomi; G. Zito; X. Huang; J. Lin; Q. Ouyang; T. Wang; Y. Xie; R. Xu; S. Xue; J. Zhang; L. Zhang; W. Zhao; D. Abbaneo; R. Alemany; U. Becker; A. O Bazarko; P. Bright-Thomas; M. Cattaneo; F. Cerutti; G. Dissertori; H. Drevermann; R. W Forty; M. Frank; R. Hagelberg; J. B Hansen; J. Harvey; P. Janot; B. Jost; E. Kneringer; J. Knobloch; I. Lehraus; G. Lutters; P. Mato; A. Minten; L. Moneta; A. Pacheco; J.-F Pusztaszeri; F. Ranjard; G. Rizzo; L. Rolandi; D. Rousseau; D. Schlatter; M. Schmitt; O. Schneider; W. Tejessy; I. R Tomalin; H. Wachsmuth; A. Wagner; Z. Ajaltouni; A. Barrès; C. Boyer; A. Falvard; C. Ferdi; P. Gay; C. Guicheney; P. Henrard; J. Jousset; B. Michel; S. Monteil; J-C Montret; D. Pallin; P. Perret; F. Podlyski; J. Proriol; P. Rosnet; J.-M Rossignol; T. Fearnley; J. D Hansen; P. H Hansen; B. S Nilsson; B. Rensch; A. Wäänänen; G. Daskalakis; A. Kyriakis; C. Markou; E. Simopoulou; I. Siotis; A. Vayaki; A. Blondel; G. Bonneaud; J. C Brient; P. Bourdon; A. Rougé; M. Rumpf; A. Valassi; M. Verderi; H. Videau; D. J Candlin; M. I. Parsons; E. Focardi; G. Parrini; K. Zachariadou; M. Corden; C. Georgiopoulos; D. E Jaffe; A. Antonelli; G. Bencivenni; G. Bologna; F. Bossi; P. Campana; G. Capon; D. Casper; V. Chiarella; G. Felici; P. Laurelli; G. Mannocchi; F. Murtas; G. P Murtas; L. Passalacqua; M. Pepe-Altarelli; L. Curtis; S. J Dorris; A. W Halley; I. G Knowles; J. G Lynch; V O'Shea; C. Raine; J. M Scarr; K. Smith; P. Teixeira-Dias; A. S Thompson; E. Thomson; F. Thomson; R. M Turnbull; C. Geweniger; G. Graefe; P. Hanke; G. Hansper; V. Hepp; E. E. Kluge; A. Putzer; M. Schmidt; J. Sommer; K. Tittel; S. Werner; M. Wunsch; R. Beuselinck; D. M Binnie; W. Cameron; P. J Dornan; M. Girone; S. Goodsir; E. B Martin; A. Moutoussi; J. Nash; J. K Sedgbeer; P. Spagnolo; A. M Stacey; M. D Williams; V. M Ghete; P. Girtler; D. Kuhn; G. Rudolph; A. P Betteridge; C. K Bowdery; P. Colrain; G. Crawford; A. J Finch; F. Foster; G. Hughes; R. W Jones; T. Sloan; M. I. Williams; A. Galla; I. Giehl; A. M Greene; C. Hoffmann; K. Jakobs; K. Kleinknecht; G. Quast; B. Renk; E. Rohne; H.-G Sander; P van Gemmeren; C. Zeitnitz; J. J. Aubert; C. Benchouk; A. Bonissent; G. Bujosa; D. Calvet; J. Carr; P. Coyle; C. Diaconu; F. Etienne; N. Konstantinidis; O. Leroy; F. Motsch; P. Payre; M. Talby; A. Sadouki; M. Thulasidas; K. Trabelsi; M. Aleppo; F. Ragusa; R. Berlich; W. Blum; V. Büscher; H. Dietl; G. Ganis; C. Gotzhein; H. Kroha; G. Lütjens; G. Lutz; W. Männer; H.-G Moser; R. Richter; A. Rosado-Schlosser; S. Schael; R. Settles; H. Seywerd; R. St Denis; H. Stenzel; W. Wiedenmann; G. Wolf; J. Boucrot; O. Callot; S. Chen; Y. Choi; A. Cordier; M. Davier; L. Duflot; J.-F Grivaz; Ph. Heusse; A. Höcker; A. Jacholkowska; M. Jacquet; D. W Kim; F Le Diberder; J. Lefrançois; A.-M Lutz; I. Nikolic; M.-H Schune; S. Simion; E. Tournefier; J.-J. Veillet; I. Videau; D. Zerwas; P. Azzurri; G. Bagliesi; G. Batignani; S. Bettarini; C. Bozzi; G. Calderini; M. Carpinelli; M. A Ciocci; V. Ciulli; R Dell'Orso; R. Fantechi; I. Ferrante; L. Foà; F. Forti; A. Giassi; M. A Giorgi; A. Gregorio; F. Ligabue; A. Lusiani; P. S Marrocchesi; A. Messineo; F. Palla; G. Sanguinetti; A. Sciabà; J. Steinberger; R. Tenchini; G. Tonelli; C. Vannini; A. Venturi; P. G Verdini; G. A Blair; L. M Bryant; J. T Chambers; Y. Gao; M. G Green; T. Medcalf; P. Perrodo; J. A Strong; J. H von Wimmersperg-Toeller; D. R Botterill; R. W Clifft; T. R Edgecock; S. Haywood; P. Maley; P. R Norton; J. C Thompson; A. E Wright; B. Bloch-Devaux; P. Colas; S. Emery; W. Kozanecki; E. Lançon; M. C Lemaire; E. Locci; P. Perez; J. Rander; J.-F Renardy; A. Roussarie; J.-P Schuller; J. Schwindling; A. Trabelsi; B. Vallage; S. N Black; J. H Dann; R. P Johnson; H. Y Kim; A. M Litke; M. A McNeil; G. Taylor; C. N Booth; R. Boswell; C. A. J Brew; S. Cartwright; F. Combley; M. S Kelly; M. Lehto; W. M Newton; J. Reeve; L. F Thompson; A. Böhrer; S. Brandt; G. Cowan; C. Grupen; P. Saraiva; L. Smolik; F. Stephan; M. Apollonio; L. Bosisio; R Della Marina; G. Giannini; B. Gobbo; G. Musolino; J. Rothberg; S. Wasserbaech; S. R Armstrong; E. Charles; P. Elmer; D. P. S Ferguson; S. González; T. C Greening; O. J Hayes; H. Hu; S. Jin; P. A McNamara; J. M Nachtman; J. Nielsen; W. Orejudos; Y. B Pan; Y. Saadi; I. J Scott; J. Walsh; Sau Lan Wu; X. Wu; J. M Yamartino; G. Zobernig

1997-01-01

227

Abundance of dinucleotide repeats and gene expression are inversely correlated: a role for gene function in addition to intron length.  

PubMed

High and broad transcription of eukaryotic genes is facilitated by cost minimization, clustered localization in the genome, elevated G+C content, and low nucleosome formation potential. In this scenario, illumination of correlation between abundance of (TG/CA)(n>or=12) repeats, which are negative cis modulators of transcription, and transcriptional levels and other commonly occurring dinucleotide repeats, is required. Three independent microarray datasets were used to examine the correlation of (TG/CA)(n>or=12) and other dinucleotide repeats with gene expression. Compared with the expected equi-distribution pattern under neutral model, highly transcribed genes were poor in repeats, and conversely, weakly transcribed genes were rich in repeats. Furthermore, the inverse correlation between repeat abundance and transcriptional levels appears to be a global phenomenon encompassing all genes regardless of their breadth of transcription. This selective pattern of exclusion of (TG/CA)(n>or=12) and (AT)(n>or=12) repeats in highly transcribed genes is an additional factor along with cost minimization and elevated GC, and therefore, multiple factors govern high transcription of genes. We observed that even after controlling for the effects of GC and average intron lengths, the effect of repeats albeit somewhat weaker was persistent and definite. In the ribosomal protein coding genes, sequence analysis of orthologs suggests that negative selection for repeats perhaps occurred early in evolution. These observations suggest that negative selection of (TG/CA)(n>or=12) microsatellites in the evolution of the highly expressed genes was also controlled by gene function in addition to intron length. PMID:17550993

Sharma, Vineet K; Kumar, Naveen; Brahmachari, Samir K; Ramachandran, Srinivasan

2007-06-05

228

Electron Bunch Length Measurements in the E-167 Plasma Wakefield Experiment  

SciTech Connect

Bunch length is of prime importance to beam driven plasma wakefield acceleration experiments due to its inverse relationship to the amplitude of the accelerating wake. We present here a summary of work done by the E167 collaboration measuring the SLAC ultra-short bunches via autocorrelation of coherent transition radiation. We have studied material transmission properties and improved our autocorrelation traces using materials with better spectral characteristics.

Blumenfeld, I.; Auerbach, D.; Berry, M.; Clayton, C.E.; Decker, F.J.; Hogan, M.J.; Huang, Cheng-Kun; Ischebeck, R.; Iverson, R.; Johnson, D.; Joshi, C.; Katsouleas, T.; Kirby, N.; Lu, Wei; Marsh, K.A.; Mori, W.B.; Muggli, P.; Oz, E.; Siemann, R.H.; Walz, D.; Zacherl, W.; /SLAC /UCLA /Southern California U.

2007-03-27

229

Bunch length and phase stability measurements at the TESLA test facility  

Microsoft Academic Search

Electron bunch lengths and time jitters have been measured with sub-ps resolution at the TESLA Test Facility at DESY. Synchrotron radiation emitted from a dipole magnet reflects the longitudinal charge distribution of the electron bunch and can also be used as a timing reference of the radiation pulses produced by the free-electron laser. For sub-ps time resolution, dispersion effects of

Ch. Gerth; J. Feldhaus; K. Honkavaara; K. D Kavanagh; Ph. Piot; L. Plucinski; S. Schreiber; I. Will

2003-01-01

230

On the measurement of slip length for liquid flow over super-hydrophobic surface  

Microsoft Academic Search

To design a surface with large slip or larger drag reduction is a pop issue in the fields of liquid transporting and body\\u000a swimming. In this context, it is a crucial problem to measure the slip length for these surfaces. Here we propose a novel\\u000a method by using rheometer for this objective. This method is implemented by designing the distribution

Jian Li; Ming Zhou; Lan Cai; Xia Ye; Run Yuan

2009-01-01

231

Measurement of atmospheric coherence length with differential movement of the image sensor  

NASA Astrophysics Data System (ADS)

This paper gives the introduction about a new measuring device which is to measure th e atmospheric coherence length by using the differential movement principle.The system can observe the edge of the sun in the day time, and also observe planets at night. This system can measure the atmospheric coherence length in both horizontal and slant directions. The measurement in the day time requests the assistance of the attenuator and beacon beam of the atmospheric coherence length in the direction of the slant path.The working principle is the laser beam scattered by atmospheric turbulence through into the receiving optical system. Because the receiving system which is consists of two completely symmetrical telephoto optical system. Therefore?two optical channels in turbulence device are completely identical. After passing through the optical channels, the beam focusing is finished. By adjusting the optical system manually or automatically, two light point images can be formed on the photosensitive element of the CCD. Atmospheric turbulence can cause phase fluctuation of wave front. After aggregation by the receiving lens, The photosensitive element of CCD can collect the relative jitter of the two imaging optical centroid positions we require, and researchers can obtain relative changes from the two centroid positions by the calculations of computer software, as the result, the atmospheric coherence length is obtained. By means of the simulation of the optical system and the imaging quality optimization by Code V, researchers can rather achieve transfer function diagram, the circle of confusion value in different views and energy distribution. From above, researchers can examine whether the optical system is being qualified, or the method is leading to a better observation effect. At end of this dissertation, the limitations of this system will be analyzed, and the improvement methods and suggestions will be provided.

Jia, Yu-gang; Tong, Shou-feng

2013-08-01

232

Absolute Bunch Length Measurements at the ALS by Incoherent Synchrotron Radiation Fluctuation Analysis  

SciTech Connect

By analyzing the pulse to pulse intensity fluctuations of the radiation emitted by a charge particle in the incoherent part of the spectrum, it is possible to extract information about the spatial distribution of the beam. At the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory, we have developed and tested a simple scheme based on this principle that allows for the absolute measurement of the bunch length. A description of the method and the experimental results are presented.

Filippetto, D.; /Frascati; Sannibale, F.; Zolotorev, Max Samuil; /LBL, Berkeley; Stupakov, G.V.; /SLAC

2008-01-24

233

Measurements of Green Laser-Beam Propagation and Backscatter in Long-Scale Length Plasmas  

Microsoft Academic Search

Summary form only given. We have implemented a complete set of optical diagnostics at the Omega laser to measure propagation and backscatter of a green (527 nm) high intensity laser beam (1015 W\\/cm2) in large-scale length, laser produced plasmas. The diagnostics include a transmitted beam diagnostic (TBD), a full aperture backscatter station (FABS) as well as a near backscatter imager

C. Niemann; L. Divol; D. Froula; S. Glenzer; G. Gregori; R. Kirkwood; A. Mackinnon; N. Meezan; J. Moody; C. Sorce; R. Bahr; W. Seka

2005-01-01

234

A new Ultra Precision Interferometer for absolute length measurements down to cryogenic temperatures  

Microsoft Academic Search

A new Ultra Precision Interferometer (UPI) was built at Physikalisch-Technische Bundesanstalt. As its precursor, the precision interferometer, it was designed for highly precise absolute length measurements of prismatic bodies, e.g. gauge blocks, under well-defined temperature conditions and pressure, making use of phase stepping imaging interferometry. The UPI enables a number of enhanced features, e.g. it is designed for a much

R Schödel; A Walkov; M Zenker; G Bartl; R Meeß; D Hagedorn; C Gaiser; G Thummes; S Heltzel

2012-01-01

235

Physics behind the minimum of relative entropy measures for correlations  

NASA Astrophysics Data System (ADS)

The relative entropy of a correlated state and an uncorrelated reference state is a reasonable measure for the degree of correlations. A key question is, however, which uncorrelated state to compare to. The relative entropy becomes minimal for the uncorrelated reference state that has the same one-particle density matrix as the correlated state. Hence, this particular measure, coined nonfreeness, is unique and reasonable. We demonstrate that for relevant physical situations, such as finite temperatures or a correlation enhanced orbital splitting, other choices of the uncorrelated state, even educated guesses, overestimate correlations.

Held, Karsten; Mauser, Norbert J.

2013-07-01

236

Noise Correlation Measurements on the 3D Disordered Bose-Hubbard Model  

NASA Astrophysics Data System (ADS)

Atomic shot noise correlations can be used to study hidden order---or lack thereof---in atomic Bose-Hubbard (BH) systems and may be a promising tool for exploring the properties of the disordered BH model. To approach this model, an optical speckle field is used to add fine-grained disorder to a 3D optical lattice. The correlation length of the speckle field is less than twice the lattice period along all three lattice directions. We will discuss atomic shot noise correlation measurements on ultra-cold atom clouds released from this disordered 3D optical lattice.

Pasienski, Matthew; White, Matthew; McKay, David; Demarco, Brian

2008-05-01

237

Measure of nonclassical correlation in coherence-vector representation  

SciTech Connect

We consider the coherence-vector representation of a bipartite state and obtain a necessary and sufficient condition for a zero-discord state. Based on this, a measure of quantum, classical, and total amount of correlations in bipartite states is proposed in this representation. Analytical expressions for this measure are available for any bipartite states. Our measure of nonclassical correlation coincides with the geometric measure of quantum discord for some particular states.

Zhou, Tao; Cui, Jingxin [State Key Laboratory of Low-dimensional Quantum Physics and Department of Physics, Tsinghua University, 100084 Beijing (China); Long, Gui Lu [State Key Laboratory of Low-dimensional Quantum Physics and Department of Physics, Tsinghua University, 100084 Beijing (China); Tsinghua National Laboratory for Information Science and Technology, Tsinghua University, 100084 Beijing (China)

2011-12-15

238

Scattering length measurements from radiative pion capture and neutron-deuteron breakup  

SciTech Connect

The neutron-neutron and neutron-proton {sup 1}S{sub 0} scattering lengths a{sub nn} and a{sub np}, respectively, were determined simultaneously from the neutron-deuteron breakup reaction. Their comparison with the recommended values obtained from two body reactions gives a measure of the importance of three-nucleon force effects in the three-nucleon continuum. In order to check on the result obtained for a{sub nn} from the two-body {pi}{sup {minus}}-d capture reaction, a new measurement was performed at LANL. Preliminary results of the three experiments are given.

Gibson, B.F. [Los Alamos National Lab., NM (United States); Tornow, W. [Duke Univ., Durham, NC (United States). Dept. of Physics]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Carman, T.S. [Lawrence Livermore National Lab., CA (United States)] [and others

1997-07-01

239

Device for the Electron Bunch Length Measurement in the Range of 1 - 5 mm rms.  

NASA Astrophysics Data System (ADS)

A device for the measurement of electron beam length in the interval 1-5 mm rms, operating at four frequencies was offered. For the monitor design simplifying two cavities were chosen, every of them being calculated at two modes : E010 and E110. The frequencies of these modes were determined as 4.5GHz, 7.2GHz for the first cavity and 11.3GHz, 18.0GHz for the second one. The coupling holes for the resonators were calculated and coupling coefficients were measured. The calibration methods for this device were proposed.

Sobenin, N. P.; Barabanov, A. G.; Zverev, B. V.; Zavadtsev, A. A.; Holtkamp, N.; Dohlus, M.

1997-05-01

240

Internalized Heterosexism: Measurement, Psychosocial Correlates, and Research Directions  

ERIC Educational Resources Information Center

|This article provides an integrated critical review of the literature on internalized heterosexism/internalized homophobia (IH), its measurement, and its psychosocial correlates. It describes the psychometric properties of six published measures used to operationalize the construct of IH. It also critically reviews empirical studies on correlates

Szymanski, Dawn M.; Kashubeck-West, Susan; Meyer, Jill

2008-01-01

241

A new Ultra Precision Interferometer for absolute length measurements down to cryogenic temperatures  

NASA Astrophysics Data System (ADS)

A new Ultra Precision Interferometer (UPI) was built at Physikalisch-Technische Bundesanstalt. As its precursor, the precision interferometer, it was designed for highly precise absolute length measurements of prismatic bodies, e.g. gauge blocks, under well-defined temperature conditions and pressure, making use of phase stepping imaging interferometry. The UPI enables a number of enhanced features, e.g. it is designed for a much better lateral resolution and better temperature stability. In addition to the original concept, the UPI is equipped with an external measurement pathway (EMP) in which a prismatic body can be placed alternatively. The temperature of the EMP can be controlled in a much wider range compared to the temperature of the interferometer's main chamber. An appropriate cryostat system, a precision temperature measurement system and improved imaging interferometry were established to permit absolute length measurements down to cryogenic temperature, demonstrated for the first time ever. Results of such measurements are important for studying thermal expansion of materials from room temperature towards less than 10 K.

Schödel, R.; Walkov, A.; Zenker, M.; Bartl, G.; Meeß, R.; Hagedorn, D.; Gaiser, C.; Thummes, G.; Heltzel, S.

2012-09-01

242

Single-Molecule Measurements of the Persistence Length of Double-Stranded RNA  

PubMed Central

Over the past few years, it has become increasingly apparent that double-stranded RNA (dsRNA) plays a far greater role in the life cycle of a cell than previously expected. Numerous proteins, including helicases, polymerases, and nucleases interact specifically with the double helix of dsRNA. To understand the detailed nature of these dsRNA-protein interactions, the (bio)chemical, electrostatic, and mechanical properties of dsRNA need to be fully characterized. We present measurements of the persistence length of dsRNA using two different single-molecule techniques: magnetic tweezers and atomic force microscopy. We deduce a mean persistence length for long dsRNA molecules of 63.8 ± 0.7 nm from force-extension measurements with the magnetic tweezers. We present atomic force microscopy images of dsRNA and demonstrate a new method for analyzing these, which yields an independent, yet consistent value of 62 ± 2 nm for the persistence length. The introduction of these single-molecule techniques for dsRNA analysis opens the way for real-time, quantitative analysis of dsRNA-protein interactions.

Abels, J. A.; Moreno-Herrero, F.; van der Heijden, T.; Dekker, C.; Dekker, N. H.

2005-01-01

243

Divergence of the correlation length for critical planar FK percolation with 1 ? q ? 4 via parafermionic observables  

NASA Astrophysics Data System (ADS)

Parafermionic observables were introduced by Smirnov for planar Fortuin-Kasteleyn (FK) percolation in order to study the critical phase (p, q) = (pc(q), q). This paper gathers several known properties of these observables. Some of these properties are used to prove the divergence of the correlation length when approaching the critical point for FK percolation when 1 ? q ? 4. A crucial step is to consider FK percolation on the universal cover of the punctured plane. We also mention several conjectures on FK percolation with arbitrary cluster weight q > 0. This article is part of ‘Lattice models and integrability’, a special issue of Journal of Physics A: Mathematical and Theoretical in honour of F Y Wu's 80th birthday.

Duminil-Copin, H.

2012-12-01

244

Development of a scanning tunneling potentiometry system for measurement of electronic transport at short length scales  

NASA Astrophysics Data System (ADS)

It is clear that complete understanding of macroscopic properties of materials is impossible without a thorough knowledge of behavior at the smallest length scales. While the past 25 years have witnessed major advances in a variety of techniques that probe the nanoscale properties of matter, electrical transport measurements -- the heart of condensed matter research -- have lagged behind, never progressing beyond bulk measurements. This thesis describes a scanning tunneling potentiometry (STP) system developed to simultaneously map the transport-related electrochemical potential distribution of a biased sample along with its surface topography, extending electronic transport measurements to the nanoscale. Combining a novel sample biasing technique with a continuous current-nulling feedback scheme pushes the noise performance of the measurement to its fundamental limit - the Johnson noise of the STM tunnel junction. The resulting 130 nV voltage sensitivity allows us to spatially resolve local potentials at scales down to 2 nm, while maintaining atomic scale STM imaging, all at scan sizes of up to 15 microns. A mm-range two-dimensional coarse positioning stage and the ability to operate from liquid helium to room temperature with a fast turn-around time greatly expand the versatility of the instrument. Use of carefully selected model materials, combined with excellent topographic and voltage resolution has allowed us to distinguish measurement artifacts caused by surface roughness from true potentiometric features, a major problem in previous STP measurements. The measurements demonstrate that STP can produce physically meaningful results for homogeneous transport as well as non-uniform conduction dominated by material microstructures. Measurements of several physically interesting materials systems are presented as well, revealing new behaviors at the smallest length sales. The results establish scanning tunneling potentiometry as a useful tool for physics and materials science.

Rozler, Michael

245

Bunch Length Measurements at the ATF Damping Ring in April 2000  

SciTech Connect

We want to accurately know the energy spread and bunch length dependence on current in the ATF damping ring. One reason is to know the strength of the impedance: From the energy spread measurements we know whether or not we are above the threshold to the microwave instability, and from the energy spread and bunch length measurements we find out the extent of potential-well bunch lengthening (PWBL). Another reason for these measurements is to help in our understanding of the intra-beam scattering (IBS) effect in the ATF. The ATF as it is now, running below design energy and with the wigglers turned off, is strongly affected by IBS. To check for consistency with IBS theory of, for example, the measured vertical beam size, we need to know all dimensions of the beam, including the longitudinal one. But beyond this practical reason for studying IBS, IBS is currently a hot research topic at many accelerators around the world (see e.g. Ref. [1]), and the effect in actual machines is not well understood. Typically, when comparing theory with measurements fudge factors are needed to get agreement (see e.g. Ref. [1]). With its strong IBS effect, the ATF is an ideal machine for studying IBS, and an indispensable ingredient for this study is a knowledge of the longitudinal phase space of the beam. The results of earlier bunch lengthening measurements in the ATF can be found in Refs. [2]-[4]. Measurements of current dependent effects, especially bunch length measurements using a streak camera, can be difficult to perform accurately. For example, space charge in the camera itself can lead to systematic errors in the measurement results. It is important the results be accurate and reproducible. In the measurements of both December 1998[3] and December 1999[4], by using light filters, the authors first checked that space charge in the streak camera was not significant. And then the Dec 99 authors show that their results agree with those Dec 98, i.e. on the dates of the two measurements the results were reproducible. Since IBS is so strong in the ATF, in the Dec 99 measurements an attempt was made to estimate the impedance effect using the following method: First, from the form of the energy spread vs. current measurements it was concluded that the threshold to the microwave instability was beyond 2 mA. Then, by dividing the bunch length vs. current curve by the energy spread vs. current curve the effect of IBS was divided out, and PWBL was approximated. The assumption is that PWBL can be treated as a perturbation on top of IBS. The result was that this component of bunch lengthening was found to grow by 7-15% (depending on the rf voltage) between the currents of .5 mA and 2 mA, about a factor of 3 less than the total bunch length growth. The conclusion was that the inductive component of the impedance was small, in fact much smaller than had been concluded earlier in Ref. [2]. Electron machines generally run in a parameter regime where IBS is an insignificant effect, and impedance measurements and calculations have also normally been performed for machines where IBS is unimportant. To simplify the interpretation of the impedance from bunch length measurements, in April 2000 the energy spread and bunch length measurements of Dec 99 were repeated, but now with the beam on a linear (difference) coupling resonance, where the horizontal and vertical emittances were approximately equal. For this case the effect of IBS was expected to be very small. An energy spread vs. current measurement under such conditions will also allow us to more clearly see whether we reach the threshold to the microwave instability. As part of the April data taking we, in addition, repeated the earlier off-coupling measurements, in order to check the reproducibility of the earlier results. In this report we present and analyze this recent set of data, and compare it with the results of the earlier measurements, particularly those of Dec 99. The measurements and analysis of data in this report follow essentially the same procedure as was used in Ref. [4]. In the prese

Bane, K.L.F.; /SLAC; Naito, T.; Okugi, T.; Urakawa, J.; /KEK, Tsukuba

2005-12-19

246

Fatigue and mood correlates of sleep length in three age-social groups: School children, students, and employees.  

PubMed

The aim of the study was to trace the consequences of insufficient sleep, in terms of chronic sleep reduction rather than acute sleep deprivation, on fatigue, mood, cognitive performance self-estimations, and daytime sleepiness in different age-social groups. The age group of the subjects reflects their social situation and their working time organization: adolescents (n = 191) obeyed the strict school schedules with starting times often before 08:00 h; university students (n = 115) had more flexible timetables; young employees (n = 126) were engaged in regular morning schedules or irregular daytime hours or day and night shifts. A questionnaire study determined the declared need of sleep, self-reported sleep length, chronic fatigue (using a scale comprised of eight fatigue symptoms and four mood and three cognitive items), and daytime sleepiness (Epworth Sleepiness Scale). The declared need for sleep decreased in subsequent age groups from 9 h 23 min in school children to 8 h 22 min in university students and to 7 h 37 min in young employees. Consequently, the discrepancy between preferred and real sleep length (sleep deficit) was the largest in adolescents: 106 min. Females showed a greater need of sleep than males (p = .025) and significantly more fatigue, mood, and cognitive problems; they also exhibited higher level of daytime sleepiness (p < .000). The sleep index (reported sleep length related to requirements) correlated significantly with all health issues in women (p < .000), while only with fatigue symptoms in men (p = .013). Actual sleep length was unrelated to mood and fatigue issues; the declared individual need of sleep and sleep index showed significant associations, especially in the group of adolescents. The most frequent complaints of adolescents included tiredness on awakening (46%), nervousness, and general weakness; university students reported excessive drowsiness (50%), tension, and nervousness; employees suffered mostly from negative moods, such as tension (49%), nervousness, and irritability. The findings of the study indicate that chronic sleep loss seems to affect females more severely than males. The associations of fatigue and mood with sleep need and sleep index were more pronounced in younger subjects. Surprisingly, fatigue symptoms in school children and university students were as frequent as in hard-working adults. Because the problem of insufficient sleep is already present in youngsters, their work time organization needs more attention. PMID:17190716

Oginska, Halszka; Pokorski, Janusz

2006-01-01

247

Correlation between live and post mortem skull conductivity measurements.  

PubMed

The skull is a tissue with a widely controversial range of conductivity values. This article correlates live skull conductivity measurements with post mortem conductivity measurements with a scaling factor ranging between 2.5 and 4. The scaling factor is validated by a mathematical model that determines the skull conductivity using saline and cerebrospinal fluid (CSF) conductivities and correlated with published physical live and post mortem skull conductivity measurements which show support for this live-to-post mortem scale factor. PMID:17947075

Wendel, Katrina; Malmivuo, Jaakko

2006-01-01

248

Corner cube reflector lateral displacement evaluation simultaneously with interferometer length measurement  

NASA Astrophysics Data System (ADS)

The novel corner cube reflector (CCR) system for a distance measuring interferometer is presented. The proposed system allows reflector lateral displacement evaluation (relative to the beam axis) simultaneously with the interferometer length measurement. Laser beam in measuring arm of the interferometer is divided into two parallel beams that are used for the interferometer distance measurement and lateral shifts of the assembly in relation to the beam axis.The CCR assembly is based on applying a position sensitive detector placed behind the CCR that has truncated vertex. Due to the proposed configuration of the cube corner and photodetector, the rotations of the CCR assembly does not cause error in the lateral displacement measurement in relation to the beam axis.The theoretical analysis and experimental verification of the system metrological feasibilities are presented. The general limitations and design problems are shown. The proposed system can be used basically for measurement and compensation of global or local cosine errors especially in short range of the interferometer displacement measurement, where known techniques are ineffective. Possible applications of the system for Coordinate Measuring Machines accuracy testing are indicated.

Zamiela, Grzegorz; Dobosz, Marek

2013-09-01

249

Note: Emittance measurements of intense pulsed proton beam for different pulse length and repetition rate  

SciTech Connect

The high intensity ion source (SILHI), in operation at CEA-Saclay, has been used to produce a 90 mA pulsed proton beam with pulse length and repetition rates suitable for the European Spallation Source (ESS) linac. Typical r-r{sup '} rms normalized emittance values smaller than 0.2{pi} mm mrad have been measured for operation in pulsed mode (0.01 < duty cycle < 0.15 and 1 ms < pulse duration < 10 ms) that are relevant for the design update of the Linac to be used at the ESS in Lund.

Miracoli, R. [ESS Bilbao, Vizcaya (Spain); INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Gammino, S.; Celona, L.; Mascali, D. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Castro, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Universita degli studi di Catania, Dipartimento di Fisica e Astronomia, V. S. Sofia 64, 95123 Catania (Italy); Gobin, R.; Delferriere, O.; Adroit, G.; Senee, F. [CEA-IRFU, Gif sur Yvette Cedex (France); Ciavola, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); CNAO, Str. Pr. Campeggi, Pavia (Italy)

2012-05-15

250

Ladybug Lengths  

NSDL National Science Digital Library

This lesson introduces students to the measurable attribute of length and provides practice in measuring length using non-standard units. The lesson is launched using the story Ladybug on the Move by Richard Fowler. Lesson objectives, teaching ideas, and handouts are included.

2012-01-01

251

Ladybug Lengths  

NSDL National Science Digital Library

This experience focuses studentâs attention on the attributes of length and gives students the opportunity to develop knowledge of and skills in using nonstandard units of measurement. The lesson begins with a connection to children's literature. As students practice measuring length, they do so using nonstandard units.

Math, Illuminations N.

2009-01-28

252

Measurement of s-wave scattering lengths in a two-component Bose-Einstein condensate  

NASA Astrophysics Data System (ADS)

We use collective oscillations of a two-component Bose-Einstein condensate (2CBEC) of 87Rb atoms prepared in the internal states |1>?|F=1,mF=?1> and |2>?|F=2,mF=1> for the precision measurement of the interspecies scattering length a12 with a relative uncertainty of 1.6×10?4. We show that in a cigar-shaped trap the three-dimensional (3D) dynamics of a component with a small relative population can be conveniently described by a one-dimensional (1D) Schrödinger equation for an effective harmonic oscillator. The frequency of the collective oscillations is defined by the axial trap frequency and the ratio a12/a11, where a11 is the intraspecies scattering length of a highly populated component 1 and is largely decoupled from the scattering length a22, the total atom number and loss terms. By fitting numerical simulations of the coupled Gross-Pitaevskii equations to the recorded temporal evolution of the axial width we obtain the value a12=98.006(16)a0, where a0 is the Bohr radius. Our reported value is in reasonable agreement with the theoretical prediction a12=98.13(10)a0 but deviates significantly from the previously measured value a12=97.66a0 [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.99.190402 99, 190402 (2007)] which is commonly used in the characterization of spin dynamics in degenerate 87Rb atoms. Using Ramsey interferometry of the 2CBEC we measure the scattering length a22=95.44(7)a0 which also deviates from the previously reported value a22=95.0a0 [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.99.190402 99, 190402 (2007)]. We characterize two-body losses for component 2 and obtain the loss coefficients ?12=1.51(18)×10?14cm3/s and ?22=8.1(3)×10?14cm3/s.

Egorov, M.; Opanchuk, B.; Drummond, P.; Hall, B. V.; Hannaford, P.; Sidorov, A. I.

2013-05-01

253

Measurement of the transverse spin correlation in Z -> ?+?- decays  

NASA Astrophysics Data System (ADS)

The measurement of the correlation between the transverse spin components of ?+?- pairs collected during 1992 to 1994 with the DELPHI detector at LEP1 is presented. A value CTT = 0.87 +/- 0.20 (stat.)+0.10-0.12 (syst.) was obtained for the correlation parameter, in agreement with the Standard Model expectation.

Abreu, P.; Adam, W.; Adye, T.; Ajinenko, I.; Alekseev, G. D.; Alemany, R.; Allport, P. P.; Almehed, S.; Amaldi, U.; Amato, S.; Andersson, P.; Andreazza, A.; Antilogus, P.; Apel, W.-D.; Åsman, B.; Augustin, J.-E.; Augustinus, A.; Baillon, P.; Bambade, P.; Barao, F.; Barbi, M.; Bardin, D. Y.; Barker, G.; Baroncelli, A.; Barring, O.; Bates, M. J.; Battaglia, M.; Baubillier, M.; Baudot, J.; Becks, K.-H.; Begalli, M.; Beilliere, P.; Belokopytov, Yu.; Belous, K.; Benvenuti, A. C.; Berggren, M.; Bertini, D.; Bertrand, D.; Besancon, M.; Bianchi, F.; Bigi, M.; Bilenky, M. S.; Billoir, P.; Bizouard, M.-A.; Bloch, D.; Blume, M.; Bonesini, M.; Bonivento, W.; Booth, P. S. L.; Borgland, A. W.; Borisov, G.; Bosio, C.; Botner, O.; Boudinov, E.; Bouquet, B.; Bourdarios, C.; Bowcock, T. J. V.; Bozovic, I.; Bozzo, M.; Branchini, P.; Brand, K. D.; Brenke, T.; Brenner, R. A.; Bricman, C.; Brown, R. C. A.; Bruckman, P.; Brunet, J.-M.; Bugge, L.; Buran, T.; Burgsmueller, T.; Buschmann, P.; Cabrera, S.; Caccia, M.; Calvi, M.; Camacho Rozas, A. J.; Camporesi, T.; Canale, V.; Canepa, M.; Cao, F.; Carena, F.; Carroll, L.; Caso, C.; Castillo Gimenez, M. V.; Cattai, A.; Cavallo, F. R.; Chabaud, V.; Charpentier, Ph.; Chaussard, L.; Checchia, P.; Chelkov, G. A.; Chen, M.; Chierici, R.; Chliapnikov, P.; Chochula, P.; Chorowicz, V.; Cindro, V.; Collins, P.; Contri, R.; Cortina, E.; Cosme, G.; Cossutti, F.; Cowell, J.-H.; Crawley, H. B.; Crennell, D.; Crosetti, G.; Cuevas Maestro, J.; Czellar, S.; Dahm, J.; Dalmagne, B.; Dam, M.; Damgaard, G.; Dauncey, P. D.; Davenport, M.; da Silva, W.; Deghorain, A.; della Ricca, G.; Delpierre, P.; Demaria, N.; de Angelis, A.; de Boer, W.; de Brabandere, S.; de Clercq, C.; de La Vaissiere, C.; de Lotto, B.; de Min, A.; de Paula, L.; Dijkstra, H.; di Ciaccio, L.; di Diodato, A.; Djannati, A.; Dolbeau, J.; Doroba, K.; Dracos, M.; Drees, J.; Drees, K.-A.; Dris, M.; Durand, J.-D.; Edsall, D.; Ehret, R.; Eigen, G.; Ekelof, T.; Ekspong, G.; Elsing, M.; Engel, J.-P.; Erzen, B.; Espirito Santo, M.; Falk, E.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Ferrari, P.; Ferrer, A.; Fichet, S.; Filippas, T. A.; Firestone, A.; Fischer, P.-A.; Foeth, H.; Fokitis, E.; Fontanelli, F.; Formenti, F.; Franek, B.; Frodesen, A. G.; Fruhwirth, R.; Fulda-Quenzer, F.; Fuster, J.; Galloni, A.; Gamba, D.; Gandelman, M.; Garcia, C.; Garcia, J.; Gaspar, C.; Gasparini, U.; Gavillet, Ph.; Gazis, E. N.; Gele, D.; Gerber, J.-P.; Gokieli, R.; Golob, B.; Goncalves, P.; Gopal, G.; Gorn, L.; Gorski, M.; Gouz, Yu.; Gracco, V.; Graziani, E.; Green, C.; Grefrath, A.; Gris, P.; Grosdidier, G.; Grzelak, K.; Gumenyuk, S.; Gunther, M.; Guy, J.; Hahn, F.; Hahn, S.; Hajduk, Z.; Hallgren, A.; Hamacher, K.; Harris, F. J.; Hedberg, V.; Henriques, R.; Hernandez, J. J.; Herquet, P.; Herr, H.; Hessing, T. L.; Heuser, J.-M.; Higon, E.; Hilke, H. J.; Holmgren, S.-O.; Holt, P. J.; Holthuizen, D.; Hoorelbeke, S.; Houlden, M.; Hrubec, J.; Huet, K.; Hultqvist, K.; Jackson, J. N.; Jacobsson, R.; Jalocha, P.; Janik, R.; Jarlskog, Ch.; Jarlskog, G.; Jarry, P.; Jean-Marie, B.; Johansson, E. K.; Jonsson, L.; Jonsson, P.; Joram, C.; Juillot, P.; Kaiser, M.; Kapusta, F.; Karafasoulis, K.; Karlsson, M.; Katsanevas, S.; Katsoufis, E. C.; Keranen, R.; Khokhlov, Yu.; Khomenko, B. A.; Khovanski, N. N.; King, B.; Kjaer, N. J.; Klapp, O.; Klein, H.; Kluit, P.; Knoblauch, D.; Koene, B.; Kokkinias, P.; Konopliannikov, A.; Koratzinos, M.; Korcyl, K.; Kostioukhine, V.; Kourkoumelis, C.; Kouznetsov, O.; Krammer, M.; Kreuter, C.; Kronkvist, I.; Krumstein, Z.; Krupinski, W.; Kubinec, P.; Kucewicz, W.; Kurvinen, K.; Lacasta, C.; Laktineh, I.; Lamsa, J. W.; Lanceri, L.; Lane, D. W.; Langefeld, P.; Laugier, J.-P.; Lauhakangas, R.; Leder, G.; Ledroit, F.; Lefebure, V.; Legan, C. K.; Leisos, A.; Leitner, R.; Lemonne, J.; Lenzen, G.; Lepeltier, V.; Lesiak, T.; Libby, J.; Liko, D.; Lindner, R.; Lipniacka, A.; Lippi, I.; Loerstad, B.; Loken, J. G.; Lopez, J. M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Maehlum, G.; Mahon, J. R.; Maio, A.; Malmgren, T. G. M.; Malychev, V.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J.-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Martinez-Vidal, F.; Marti I Garcia, S.; Matorras, F.; Matteuzzi, C.; Matthiae, G.; Mazzucato, M.; Mc Cubbin, M.; Mc Kay, R.; Mc Nulty, R.; Medbo, J.; Merk, M.; Meroni, C.; Meyer, S.; Meyer, W. T.; Miagkov, A.; Michelotto, M.; Migliore, E.; Mirabito, L.; Mitaroff, W. A.; Mjoernmark, U.; Moa, T.; Moeller, R.; Moenig, K.; Monge, M. R.; Morettini, P.; Mueller, H.; Muenich, K.; Mulders, M.; Mundim, L. M.; Murray, W. J.; Muryn, B.; Myatt, G.; Naraghi, F.; Navarria, F. L.; Navas, S.; Nawrocki, K.; Negri, P.; Nemecek, S.; Neumann, W.; Neumeister, N.; Nicolaidou, R.; Nielsen, B. S.

1997-02-01

254

Quantumness of correlations revealed in local measurements exceeds entanglement  

NASA Astrophysics Data System (ADS)

We analyze a family of measures of general quantum correlations for composite systems, defined in terms of the bipartite entanglement necessarily created between systems and apparatuses during local measurements. For every entanglement monotone E, this operational correspondence provides a different measure QE of quantum correlations. Examples of such measures are the relative entropy of quantumness, the quantum deficit, and the negativity of quantumness. In general, we prove that any so-defined quantum correlation measure is always greater than (or equal to) the corresponding entanglement between the subsystems, QE?E, for arbitrary states of composite quantum systems. We analyze qualitatively and quantitatively the flow of correlations in iterated measurements, showing that general quantum correlations and entanglement can never decrease along von Neumann chains, and that genuine multipartite entanglement in the initial state of the observed system always gives rise to genuine multipartite entanglement among all subsystems and all measurement apparatuses at any level in the chain. Our results provide a comprehensive framework to understand and quantify general quantum correlations in multipartite states.

Piani, Marco; Adesso, Gerardo

2012-04-01

255

Modeling work zone crash frequency by quantifying measurement errors in work zone length.  

PubMed

Work zones are temporary traffic control zones that can potentially cause safety problems. Maintaining safety, while implementing necessary changes on roadways, is an important challenge traffic engineers and researchers have to confront. In this study, the risk factors in work zone safety evaluation were identified through the estimation of a crash frequency (CF) model. Measurement errors in explanatory variables of a CF model can lead to unreliable estimates of certain parameters. Among these, work zone length raises a major concern in this analysis because it may change as the construction schedule progresses generally without being properly documented. This paper proposes an improved modeling and estimation approach that involves the use of a measurement error (ME) model integrated with the traditional negative binomial (NB) model. The proposed approach was compared with the traditional NB approach. Both models were estimated using a large dataset that consists of 60 work zones in New Jersey. Results showed that the proposed improved approach outperformed the traditional approach in terms of goodness-of-fit statistics. Moreover it is shown that the use of the traditional NB approach in this context can lead to the overestimation of the effect of work zone length on the crash occurrence. PMID:23563145

Yang, Hong; Ozbay, Kaan; Ozturk, Ozgur; Yildirimoglu, Mehmet

2013-03-15

256

Do severity measures explain differences in length of hospital stay? The case of hip fracture.  

PubMed Central

OBJECTIVE: To examine whether judgments about hospital length of stay (LOS) vary depending on the measure used to adjust for severity differences. DATA SOURCES/STUDY SETTING: Data on admissions to 80 hospitals nationwide in the 1992 MedisGroups Comparative Database. STUDY DESIGN: For each of 14 severity measures, LOS was regressed on patient age/sex, DRG, and severity score. Regressions were performed on trimmed and untrimmed data. R-squared was used to evaluate model performance. For each severity measure for each hospital, we calculated the expected LOS and the z-score, a measure of the deviation of observed from expected LOS. We ranked hospitals by z-scores. DATA EXTRACTION: All patients admitted for initial surgical repair of a hip fracture, defined by DRG, diagnosis, and procedure codes. PRINCIPAL FINDINGS: The 5,664 patients had a mean (s.d.) LOS of 11.9 (8.9) days. Cross-validated R-squared values from the multivariable regressions (trimmed data) ranged from 0.041 (Comorbidity Index) to 0.165 (APR-DRGs). Using untrimmed data, observed average LOS for hospitals ranged from 7.6 to 23.9 days. The 14 severity measures showed excellent agreement in ranking hospitals based on z-scores. No severity measure explained the differences between hospitals with the shortest and longest LOS. CONCLUSIONS: Hospitals differed widely in their mean LOS for hip fracture patients, and severity adjustment did little to explain these differences.

Shwartz, M; Iezzoni, L I; Ash, A S; Mackiernan, Y D

1996-01-01

257

Angstrom-Range Optical Path-Length Measurement with a High-Speed Scanning Heterodyne Optical Interferometer  

NASA Astrophysics Data System (ADS)

A highly accurate method of optical path-length measurement is introduced by use of a scanning heterodyne optical interferometer with no moving parts. The instrument has demonstrated the potential to measure optical path length at angstrom resolution over continuous thickness in the micrometer range. This optical path length can be used to calculate the thickness of any material if the refractive index is known or to measure the refractive index of the material if the thickness is known. The instrument uses a single acousto-optic device in an in-line ultra-stable reflective geometry to implement rapid scanning in the microsecond domain for thickness measurements of the test medium.

Riza, Nabeel A.; Arain, Muzammil A.

2003-05-01

258

Curriculum-Based Measurement Oral Reading as an Indicator of Reading Achievement: A Meta-Analysis of the Correlational Evidence  

ERIC Educational Resources Information Center

|This meta-analysis summarized the correlational evidence of the association between the CBM Oral Reading measure (R-CBM) and other standardized measures of reading achievement for students in grades 1-6. Potential moderating variables were also examined (source of criterion test, administration format, grade level, length of time, and type of…

Reschly, Amy L.; Busch, Todd W.; Betts, Joseph; Deno, Stanley L.; Long, Jeffrey D.

2009-01-01

259

Correlation between intelligence test scores and executive function measures.  

PubMed

In this study, some executive function measures (Wisconsin Card Sorting Test [WCST], verbal fluency, and Trial Making Test [TMT], Form A and Form B) were correlated with Wechsler Intelligence Scale for Children-Revised (WISC-R) scores. Fifty 13- to 16-year-old normal children were selected. It was found that verbal fluency tests correlated about 0.30 with Verbal Intelligence Quotient (IQ) and Full Scale IQ. In the WCST only Perseverative Errors negatively correlated with Verbal IQ and Full Scale IQ. Two correlations were found to be significant with regard to the TMT: TMT Form B Errors negatively correlated with WISC-R Vocabulary subtest; and TMT Form A Time negatively correlated with Performance IQ. These results support the assumption that traditional intelligence tests are not appropriately evaluating executive functions. PMID:14590565

Ardila, A; Pineda, D; Rosselli, M

2000-01-01

260

Feasibility study for transuranic nuclide measurement on long-length contaminated equipment using neutron detection  

SciTech Connect

The feasibility of measuring the transuranic (TRU) nuclide content of equipment removed from Hanford`s high-level radioactive-waste tanks has been established for components heavier than about 30 kg/m (20 lbs/ft). This conclusion has been reached based on experience with the TRU assay of waste burial boxes, planned improvements to the assay equipment design and assay methodology, and experimental investigation of neutron detector performance in high gamma-ray fields. The experiments indicate that the neutron detectors presently used with Pacific Northwest Laboratory`s box scanner perform correctly in gamma-ray exposure rates of at least 3 R/h. The design of equipment proposed for measuring TRU content incorporates multiple, BF{sub 3}-gas-filled neutron counters in a configuration that is approximately 0.5 m wide and 2 m long, with polyethylene to moderate high-energy neutrons down to thermal energy. Specially developed electrical systems are used to eliminate response to gamma-rays. Performance of the assay would require 10 to 14 hours of time during which close-range access is provided to the waste and its burial container. A standard neutron source, will be placed within the burial container (before inserting components) to allow calibration of the detector. Final calculation of the TRU contamination will utilize plausible conservative assumptions concerning the spatial, isotopic, and elemental distributions of any TRU present. For long-length equipment, the detector array collects data at various positions along the length of the equipment. Separate monitoring of the cosmic-ray-induced neutron background during the assay period will provide confidence that observed changes in counts at the equipment are not related to changing background. Background measurements using the burial container and equipment {open_quotes}skid{close_quotes} will allow compensation for neutrons that are created by cosmic-ray spallation within the burial container.

Stromswold, D.C.; Peurrung, A.J.; Arthur, R.J. [and others

1995-10-01

261

Diffraction effects in coherent transition radiation diagnostics for sub-mm bunch length measurement  

SciTech Connect

Electrons crossing the boundary between different media generate bursts of transition radiation. In the case of bunches of N electrons, the radiation is coherent and has an N-squared enhancement at wavelengths related to the longitudinal bunch distribution. This coherent transition radiation has therefore attracted attention as an interceptive charged particle beam diagnostic technique. Many analytical descriptions have been devised describing the spectral distribution generated by electron bunches colliding with thin metallic foils making different simplifying assumptions. For typical bunches having lengths in the sub-millimeter range, measurable spectra are generated up into the millimeter range. Analysis of this THz radiation is performed using optical equipment tens of millimeters in size. This gives rise to concern that optical diffraction effects may spread the wavefront of interest into regions larger than the optical elements and partially escape detection, generating a wavelength-dependent instrument response. In this paper we present a model implementing vector diffraction theory to analyze these effects in bunch length diagnostics based on coherent transition radiation.

Maxwell, T.J.; Mihalcea, D.; /Northern Illinois U.; Piot, P.; /Northern Illinois U. /Fermilab

2008-09-01

262

Length of Stay: Managed Care Agenda or a Measure of Clinical Efficiency?  

PubMed Central

The purpose of this paper is to provide clinicians a review of the literature on length of stay (LOS) in an effort to differentiate between superficial pressure from managed care and efficient inpatient care. We included papers that were identified through an OVID Medline search. Length of stay and psychiatry were entered as search variables. Limitations placed on the search were English language, as well as years 1990 to present. On review of the search results, all case reports and editorials were eliminated. Papers with abstracts indicating that LOS was not a primary focus of the paper were also eliminated. Lastly, one paper studying adolescent patients was eliminated to improve the homogeneity of the studies under consideration. The results and discussion are presented in a qualitative fashion, citing findings of individual studies. Effort was made to give weight to studies with large samples, good study design with explanation of any limitations or shortcomings of the individual studies, and powerful findings. What we found was that despite daily pressure upon clinicians to continually reduce LOS, the body of literature examining methods to achieve this goal without sacrificing quality, as well as the outcomes of reduced LOS, is quite sparse. As this measure affects clinical management and the doctor/patient relationship, further in depth studies are needed. It appears that the best way to fulfill the clinician's responsibilities to the patients and third party payers is through improving the services already provided to the patient.

2006-01-01

263

Sonar Measurement of Fetal Crown-Rump Length as Means of Assessing Maturity in First Trimester of Pregnancy  

Microsoft Academic Search

A method is reported by which the “in utero” crown-rump length of the fetus may be determined by sonar in the first trimester of pregnancy. The accuracy of the technique was assessed by comparing the sonar and the direct postabortum measurements of fetuses in cases of missed abortion. A normal curve of fetal crown-rump length was derived from 214 examinations

Hugh P. Robinson

1973-01-01

264

Length variation in a specific region of the period gene correlates with differences in pupal diapause incidence in the flesh fly, Sarcophaga bullata.  

PubMed

We report differences in the length of a specific region of the circadian clock gene period (per) that correlate with different capacities for pupal diapause in the flesh fly, Sarcophaga bullata. The conspicuous difference is located in a region we refer to as the putative C-terminal photoperiodic (CP) region. The length of the CP region correlates inversely with the incidence of diapause. A deletion of 33 amino acids in this region correlates with a significant increase in the incidence of diapause, from 78.1% to 93.0%, and an insertion of 9 amino acids in the same area correlates with a drop in the diapause incidence to 4.0%. This correlation suggests a possible functional role for this region of per in photoperiodism. PMID:19186187

Han, Bing; Denlinger, David L

2009-01-30

265

Measuring diffusion in cell membranes by fluorescence correlation spectroscopy  

Microsoft Academic Search

Fluorescence Correlation Spectroscopy (FCS) can measure diffusion on the cell surface with unparalleled sensitivity. In appropriate situations, this can be the most sensitive and accurate method for measuring receptor interaction and oligomerization. Here we attempt to describe FCS in sufficient detail so that the reader is able to judge when there is a compelling reason to choose this technique, understand

Parijat Sengupta; J Balaji; Sudipta Maiti

2002-01-01

266

The Measurement and Correlates of Career Decision Making.  

ERIC Educational Resources Information Center

|This paper presents a theoretical framework for understanding career decision making (CDM); introduces an instrument, Assessment of Career Decision Making (ACDM) to measure CDM with college students; and presents correlational data on sex role and cognitive style factors hypothesized to influence CDM. The ACDM, designed to measure the Tiedeman…

Harren, Vincent A.; Kass, Richard A.

267

Method for single-shot measurement of picosecond laser pulse-lengths without electronic time dispersion  

SciTech Connect

A two-source shear pattern recording is proposed as a method for single-shot measurement of the pulse shape from nearly monochromatic sources whose pulse lengths are shorter than their coherence times. The basis of this method relies on the assertion that if two identical electromagnetic pulses are recombined with a time delay greater than the sum of their pulse widths, the recordable spatial pattern has no fringes in it. At an arbitrary delay, translated into an actual spatial recording position, the recorded modulated intensity will sample the corresponding laser intensity at that delay time, but with a modulation due to the coherence function of the electromagnetic pulse. Two arrangements are proposed for recording the pattern. The principles, the design parameters, and the methodologies of these arrangements will be presented. Resolutions of the configurations and their limitations will be given as well.

Kyrala, G.A.

1987-01-01

268

Local Transport Measurements at Mesoscopic Length Scales Using Scanning Tunneling Potentiometry  

NASA Astrophysics Data System (ADS)

Under mesoscopic conditions, the transport potential on a thin film carrying a current is theoretically expected to bear spatial variation due to quantum interference. Scanning tunneling potentiometry is the ideal tool to investigate such variation, by virtue of its high spatial resolution. We report in this Letter the first detailed measurement of transport potential under mesoscopic conditions. Epitaxial graphene at a temperature of 17 K was chosen as the initial system for study because the characteristic transport length scales in this material are relatively large. Tip jumping artifacts are a major possible contribution to systematic errors; and we mitigate such problems by using custom-made slender and sharp tips manufactured by focused ion beam. In our data, we observe residual resistivity dipoles associated with topographical defects, and local peaks and dips in the potential that are not associated with topographical defects.

Wang, Weigang; Munakata, Ko; Rozler, Michael; Beasley, Malcolm R.

2013-06-01

269

Measurement of the neutron-neutron scattering length using the {pi}{sup -}d capture reaction  

SciTech Connect

We have determined a value for the {sup 1}S{sub 0} neutron-neutron scattering length (a{sub nn}) from high-precision measurements of time-of-flight spectra of neutrons from the {sup 2}H({pi}{sup -},n {gamma}) n capture reaction. The measurements were done at the Los Alamos Meson Physics Facility by the E1286 Collaboration. The high spatial resolution of our {gamma}-ray detector enabled us to make a detailed assessment of the systematic uncertainties in our techniques. The value obtained in the present work is a{sub nn}=-18.63{+-}0.10 (statistical) {+-} 0.44 (systematic) {+-} 0.30 (theoretical) fm. This result is consistent with previous determinations of a{sub nn} from the {pi}{sup -}d capture reaction. We found that the analysis of the data with calculations that use a relativistic phase-space factor gives a more negative value for a{sub nn} by 0.33 fm over the analysis done using a nonrelativistic phase-space factor. Combining the present result with the previous ones from {pi}{sup -}d capture gives a{sub nn}=-18.63{+-}0.27(expt){+-}0.30 fm (theory). For the first time the combined statistical and systematic experimental uncertainty in a{sub nn} is smaller than the theoretical uncertainty and comparable to the uncertainty in the proton-proton {sup 1}S{sub 0} scattering length (a{sub pp}). This average value of a{sub nn} when corrected for the magnetic-moment interaction of the two neutrons becomes -18.9 {+-} 0.4 fm, which is 1.6 {+-} 0.5 fm different from the recommended value of a{sub pp}, thereby confirming charge symmetry breaking at the 1% confidence level.

Chen, Q.; Howell, C. R.; Kiser, M. R.; Roper, C. D.; Salinas, F.; Setze, H. R.; Tornow, W.; Walter, R. L. [Duke University and Triangle Universities Nuclear Laboratory, Durham, North Carolina (United States); Carman, T. S. [Lawrence Livermore National Laboratory, Livermore, California (United States); Gibbs, W. R. [New Mexico State University, Las Cruces, New Mexico (United States); Gibson, B. F.; Morris, C.; Obst, A.; Sterbenz, S.; Whitton, M. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Hussein, A. [University of Northern British Columbia (Canada); Mertens, G. [University of Tuebingen, Tuebingen (Germany); Moore, C. F.; Whiteley, C. R. [University of Texas, Austin, Texas (United States); Pasyuk, E. [Joint Institute of Nuclear Research, Dubna (Russian Federation)] (and others)

2008-05-15

270

Physical activity in midlife and telomere length measured in old age.  

PubMed

Physical activity has been associated with alterations in telomere length, a potential indicator of biological aging, but several inconsistencies exist. Our aim was to investigate the associations between physical activity in midlife and leukocyte telomere length (LTL) measured in old age in the Helsinki Businessmen Study, Finland. At entry, in 1974, 782 men (mean age 47) completed a questionnaire about their physical activity and this was collapsed into 3 categories: low (n=148), moderate (n=398) and high physical activity (n=236, 7 of whom had a competitive activity level). After 29-year follow-up in 2003, mean LTL and the proportion of short (<5 kB) telomeres were measured from DNA samples of a random subcohort of survivors (n=204, mean age 76) using the Southern blot technique. Adjusted for age, body mass index (BMI), cholesterol and smoking in 1974, the moderate physical activity group had longer mean LTL (8.27 kB, SE 0.05) than the low (8.10 kB, SE 0.07), or high (8.10 kB, SE 0.05) physical activity groups (P=0.03 between groups). Conversely, the proportion of short telomeres was lowest in the moderate physical activity group (11.35%, SE 0.25), and higher in the high (12.39%, SE 0.29), and the low physical activity (12.21%, SE 0.39) groups (P=0.02 between groups). We conclude that the results of this observational cohort study give support to the idea that both low and high physical activity is in the long-term associated with factors shortening LTL. PMID:22386580

Savela, Salla; Saijonmaa, Outi; Strandberg, Timo E; Koistinen, Pentti; Strandberg, Arto Y; Tilvis, Reijo S; Pitkälä, Kaisu H; Miettinen, Tatu A; Fyhrquist, Frej

2012-02-22

271

The surprising negative correlation of gene length and optimal codon use - disentangling translational selection from GC-biased gene conversion in yeast  

PubMed Central

Background Surprisingly, in several multi-cellular eukaryotes optimal codon use correlates negatively with gene length. This contrasts with the expectation under selection for translational accuracy. While suggested explanations focus on variation in strength and efficiency of translational selection, it has rarely been noticed that the negative correlation is reported only in organisms whose optimal codons are biased towards codons that end with G or C (-GC). This raises the question whether forces that affect base composition - such as GC-biased gene conversion - contribute to the negative correlation between optimal codon use and gene length. Results Yeast is a good organism to study this as equal numbers of optimal codons end in -GC and -AT and one may hence compare frequencies of optimal GC- with optimal AT-ending codons to disentangle the forces. Results of this study demonstrate in yeast frequencies of GC-ending (optimal AND non-optimal) codons decrease with gene length and increase with recombination. A decrease of GC-ending codons along genes contributes to the negative correlation with gene length. Correlations with recombination and gene expression differentiate between GC-ending and optimal codons, and also substitution patterns support effects of GC-biased gene conversion. Conclusion While the general effect of GC-biased gene conversion is well known, the negative correlation of optimal codon use with gene length has not been considered in this context before. Initiation of gene conversion events in promoter regions and the presence of a gene conversion gradient most likely explain the observed decrease of GC-ending codons with gene length and gene position.

2011-01-01

272

Exact quantum correlations of conjugate variables from joint quadrature measurements  

NASA Astrophysics Data System (ADS)

We demonstrate that for two canonically conjugate operators qˆ, pˆ, the global correlation -2, and the local correlations (p)- and (q)- can be measured exactly by Von Neumann-Arthurs-Kelly joint quadrature measurements. Here (q) and (p) denote the conditional expectation values of momentum at a given position, and position at a given momentum respectively. These correlations provide a sensitive experimental test of quantum phase space probabilities quite distinct from the probability densities of q, p. E.g. for EPR states, and entangled generalized coherent states, phase space probabilities which reproduce the correct position and momentum probability densities have to be modified to reproduce these correlations as well.

Roy, S. M.

2013-11-01

273

Design of measurement-based correlation models for shadow fading  

Microsoft Academic Search

This paper deals with the design of measurement-based correlation models for shadow fading. Based on the correlation model, we design a simulation model using the sumof-sinusoids (SOS) method to enable the simulation of spatial lognormal processes characterizing real-world shadow fading scenarios. The model parameters of the simulation model are computed by applying the Lp-norm method (LPNM). This method facilitates an

Matthias Patzold; Nurilla Avazov; V. D. Nguyen

2010-01-01

274

First Measurements of Pion Correlations by the PHENIX Experiment  

SciTech Connect

First identical-pion correlations measured at RHIC energies by PHENIX are presented. Two analyses with separate detectors, systematics, and statistics provide consistent results. The resulting HBT radii are moderately larger than those measured at lower energies. The k{sub t} dependence of the Bertsch-Pratt HBT radii is also similar to previous measures and is consistent with the conjecture of an expanding source.

Johnson, S C

2001-04-11

275

Locally Measured Neuronal Correlates of Functional MRI Signals  

Microsoft Academic Search

\\u000a Functional MRI (fMRI) utilizes changes in metabolic and hemodynamic signals in order to infer the underlying local changes\\u000a in neuronal activity. fMRI signals are therefore an indirect measure of neuronal activity, with the involvement of intermediary\\u000a processes of neurovascular coupling and MRI measurements. This chapter summarizes the current concepts surrounding the neuronal\\u000a correlates of fMRI signals measured locally and the

Amir Shmuel

276

Body mass index is inversely correlated with the expanded CAG repeat length in SCA3/MJD patients.  

PubMed

Spinocerebellar ataxia type 3, also known as Machado-Joseph disease (SCA3/MJD), is an autosomal dominant neurodegenerative disorder with no current treatment. We aimed to evaluate the body mass index (BMI) of patients with SCA3/MJD and to assess the correlations with clinical, molecular, biochemical, and neuroimaging findings. A case-control study with 46 SCA3/MJD patients and 42 healthy, non-related control individuals with similar age and sex was performed. Clinical evaluation was done with the ataxia scales SARA and NESSCA. Serum insulin, insulin-like growth factor 1 (IGF-1) and magnetic resonance imaging normalized volumetries of cerebellum and brain stem were also assessed. BMI was lower in SCA3/MJD patients when compared to controls (p?=?0.01). BMI was associated with NESSCA, expanded CAG repeat number (CAG)n, age of onset, age, disease duration, and serum insulin levels; however, in the linear regression model, (CAG)n was the only variable independently associated with BMI, in an inverse manner (R?=?-0.396, p?=?0.015). In this report, we present evidence that low BMI is not only present in SCA3/MJD, but is also directly related to the length of the expanded CAG repeats, which is the causative mutation of the disease. This association points that weight loss might be a primary disturbance of SCA3/MJD, although further detailed analyses are necessary for a better understanding of the nutritional deficit and its role in the pathophysiology of SCA3/MJD. PMID:22090366

Saute, Jonas Alex Morales; Silva, Andrew Chaves Feitosa da; Souza, Gabriele Nunes; Russo, Aline Dutra; Donis, Karina Carvalho; Vedolin, Leonardo; Saraiva-Pereira, Maria Luiza; Portela, Luis Valmor Cruz; Jardim, Laura Bannach

2012-09-01

277

Understanding the limits of pair-distribution functions for nanoscale correlation function measurement  

NASA Astrophysics Data System (ADS)

We explore the ability of the pair-distribution function (pdf) to accurately measure medium-range correlation lengths in nanoscale crystalline materials. Through simple computer simulations of disordered fcc metals, we find that the presence of quadratic displacement fields is sufficient to mask topological order (mro) at the medium-range (1 3 nm). This reconciles previous measurements and modeling on amorphous silicon—which showed that paracrystalline structures give pair correlation functions which are almost indistinguishable from random networks—with the wide use of pdfs to measure correlation lengths in nanoscale crystalline materials. Through simple analytical considerations, we identify conditions when the pdf method can be trusted for mro measurements in nanocrystalline materials. We show that while the reliability of the technique is dependent on the nature of materials studied, in general the technique fails for sufficiently small grain size in compact materials. When the pdf method does not work, we have previously shown that fluctuation microscopy is a powerful tool to give information on mro.

Gibson, J. Murray

2007-11-01

278

Comparative Study of Bunch Length And Arrival Time Measurements at FLASH  

SciTech Connect

Diagnostic devices to precisely measure the longitudinal electron beam profile and the bunch arrival time require elaborate new instrumentation techniques. At FLASH, two entirely different methods are used. The bunch profile can be determined with high precision by a transverse deflecting RF structure, but the method is disruptive and does not allow to monitor multiple bunches in a macro-pulse train. It is therefore complemented by two non-disruptive electrooptical devices, called EO and TEO. The EO setup uses a dedicated diagnostic laser synchronized to the machine RF. The longitudinal electron beam profile is encoded in the intensity profile of a chirped laser pulse and analyzed by looking at the spectral composition of the pulse. The second setup, TEO, utilizes the TiSa-based laser system used for pump-probe experiments. Here, the temporal electron shape is encoded into the spatial dimension of the laser pulse by an intersection angle between the laser and the electron beam at the EO-crystal. In this paper, we present a comparative study of bunch length and arrival time measurements performed simultaneously with all three experimental techniques.

Schlarb, H.; Azima, A.; Dusterer, S.; Huning, M.; Knabbe, E.A.; Roehrs, M.; Rybnikov, V.; Schmidt, B.; Steffen, B.; /DESY; Ross, M.C.; /SLAC; Schmueser, P.; Winter, A.; /Hamburg U.

2007-04-16

279

Measurement of the digit lengths and the anogenital distance in mice  

Microsoft Academic Search

In humans, research has demonstrated the ratio of the 2nd to 4th digit lengths (2D:4D) are: (i) sexually dimorphic with males having a lower ratio than females, the latter having near equidistant lengths [J. Manning, D. Scutt, J. Wilson, & D. Lewis-Jones, (1998). The ratio of 2nd to 4th digit length: a predictor of sperm numbers and concentrations of testosterone,

Francis Anthony Michael Manno III

2008-01-01

280

The correlation of organoleptic and instrumental halitosis measurements.  

PubMed

Numerous detection systems are available for measuring halitosis. In order to examine their agreement, a study was conducted comparing four selected measuring methods in 100 subjects (52 females, 48 males; mean age: 25 years). Organoleptic halitosis measurement was carried out by an odor judge, and compared with instrumental halitosis measurement by sulfide monitoring using Halimeter, Fresh Kiss, and Halitox (halitosis linked toxin detection assay), with which both VSC (volatile sulphur compounds) and polyamines can be detected. The results show that the values recorded by the Halimeter correlated best with the organoleptic assessment and the least with the results of Fresh Kiss. PMID:20533102

Brunner, Flavio; Kurmann, Miranda; Filippi, Andreas

2010-01-01

281

Isotope correlation verification of analytical measurements for dissolver materials  

SciTech Connect

An independent verification of analytical results for accountability measurements of dissolver materials can be performed using the Iosotop Correlation Technique (ICT). ICT is based on the relationships that exist between the initial and final elemental concentration and isotopic abundances of the nuclear fuel. Linear correlation functions between isotopic ratios and plutonium/uranium ratios have been developed for specific reactor fuels. The application of these correlations to already existing analytical data provides a laboratory additional confidence in the reported results. Confirmation is done by a test of consistancy with historical data. ICT is being utilized with dissolver accountability measurements at the Savannah River Plant Laboratory. The application, implementation, and operating experience of this technique are presented.

Satkowski, J. (E.I. du Pont de Nemours and Co., Savannah River Plant, Aiken, SC (US))

1988-01-01

282

REMOVING AN EXTRANEOUS EFFECT IN MEASURING CORRELATION COEFFICIENT  

Microsoft Academic Search

Pearson correlation coecient is a measure for the linearity degree between two con- tinuous variables (X,Y ). When this measure is spurious from an extraneous variable eect rPR, rGM and rGR are proposed and investigated through simulation technique. And, the results show that rGR , rPR perform very well in simulation I, and rGR still performs very well in simulation

Chong-Yau Fu; Min-Hsun Tsai

283

On the robustness of non-parametric correlation measures  

Microsoft Academic Search

Local robustness can be measured by means of in°uence functions (IF). The in°uence function gives us the e®ect that an outlying observation may have on an estimator. Computing the IF of the Quadrant, Spearman, and Kendall correlation measures is not di±cult. It seems that Grize (1978) was therst one who listed expressions for the IF. From the in°uence functions, gross-error

C. Dehon; F. Alqallaf; C. Croux; R. Zamar

284

Correlation of Nanoindentation and Conventional Mechanical Property Measurements.  

National Technical Information Service (NTIS)

A series of model ferritic alloys and two commercial steels were used to develop a correlation between tensile yield strength and nano-indentation hardness measurements. The NanoIndenter-II(reg-sign) was used with loads as low as 0.05 g(sub f) (0.490 mN) ...

P. M. Rice

2001-01-01

285

Correlations, Descent Measures: Drift with Migration and Mutation  

Microsoft Academic Search

The analysis of gene frequencies for a nested structure of genes within individuals, individuals within subpopulations, and subpopulations within populations is considered. Alternative parameterizations are provided by measures of correlation and of identity by descent, but the latter parameters provide more flexibility. The effects of population size, mating system, mutation, and migration can be incorporated into transition equations for identity

C. Clark Cockerham; B. S. Weir

1987-01-01

286

PROTOTYPE CORRELATION MASK FLAME PHOTOMETRIC DETECTOR FOR MEASURING SULFUR DIOXIDE  

EPA Science Inventory

A prototype flame photometric detector system (FPD) to measure gaseous sulfur compounds was fabricated using a previously developed correlation mask optical system and a new flame housing. Also, a new burner for the FPD system was optimized to view the excited molecular sulfur em...

287

Clove oil as a fish anaesthetic for measuring length and weight of rabbitfish ( Siganus lineatus)  

Microsoft Academic Search

The successful use of clove oil as a fish anaesthetic is described. Juvenile rabbitfish, Siganus lineatus, from the same cohort ranging in size from 5 to 23 cm in total length (TL) were anaesthetized, and their length and weight were recorded on three separate occasions. Fish fed shortly afterward, and no mortality was observed. Clove oil appears to be highly

Cristina G. Soto; Burhanuddin

1995-01-01

288

Measurement of Transfer Length on Prestressing Strands in Prestressed Concrete Specimens.  

National Technical Information Service (NTIS)

Recent studies had indicated that current AASHTO provisions for the transfer length and development length of 0.6-inch prestressing strand were unconservative. On the basis of very limited data, restrictions on 0.6-inch strand were adopted as an interim m...

I. O. Unay B. Russell N. Burns M. Kreger

1991-01-01

289

Evaluation of a multimode fiber optic low coherence interferometer for path length resolved Doppler measurements of diffuse light.  

PubMed

The performance of a graded index multimode fiber optic low coherence Mach-Zehnder interferometer with phase modulation is analyzed. Investigated aspects were its ability to measure path length distributions and to perform path length resolved Doppler measurements of multiple scattered photons in a turbid suspension of particles undergoing Brownian and translational motion. The path length resolution of this instrument is compared with a system using single mode fibers for illumination and detection. The optical path lengths are determined from the zero order moment of the phase modulation peak in the power spectrum. The weighted first moment, which is equal to the average Doppler shift, shows a linear response for different mean flow velocities within the physiological range. PMID:18163752

Varghese, Babu; Rajan, Vinayakrishnan; Van Leeuwen, Ton G; Steenbergen, Wiendelt

2007-12-01

290

Correlation of telomere length shortening with TP53 somatic mutations, polymorphisms and allelic loss in breast tumors and esophageal cancer.  

PubMed

Genomic instability caused by telomere erosion is an important mechanism of tumorigenesis. p53 plays a key role in cellular senescence and/or apoptosis associated with telomere erosion which positions p53 as a guard against tumorigenesis. The present study was undertaken to investigate the potential interactions between p53 functional mutations, polymorphisms, allelic loss and telomere erosion in 126 breast tumor patients and 68 esophageal cancer patients. Telomere length (TL) was measured by real-time quantitative PCR. Somatic mutations, polymorphisms and allelic loss in the TP53 gene were detected by direct sequencing of both tumor and normal tissue samples. Our results showed that telomeres were significantly shorter in tumors with somatic p53 mutations compared with tumors with wild-type p53 in both breast tumors (P=0.007) and esophageal cancer (P=0.001). Telomeres of patients with minor genotype CC of rs12951053 and GG of rs1042522 were significantly shorter compared to patients with other genotypes of this single nucleotide polymorphism in esophageal cancer tissue. Furthermore, TP53 allelic loss was detected and significantly associated with somatic mutations in both types of tumor tissues. These findings suggest that somatic p53 mutations, rs12951053 genotype CC and rs1042522 genotype GG contribute to erosion of telomeres, and TP53 allelic loss may be one of the representations of chromosomal instability caused by telomere erosion combined with somatic p53 mutations. These results support that the TP53 gene has a strong interaction with TL erosion in tumorigenesis. PMID:23124483

Hao, Xiao-Dan; Yang, Yue; Song, Xin; Zhao, Xue-Ke; Wang, Li-Dong; He, Jun-Dong; Kong, Qing-Peng; Tang, Nelson Leung Sang; Zhang, Ya-Ping

2012-10-22

291

Correlation Measurements with {sup 252}Cf to Characterize Fissile Material  

SciTech Connect

Measurements using {sup 252}Cf as a timed source of neutrons and gammas have in recent years undergone significant maturation. These methods use {sup 252}Cf as an observable source of spontaneous fission neutrons and gammas in conjunction with one or more neutron- and/or gamma-sensitive detectors to measure the time-distribution of correlated detector counts following (a) an observed {sup 252}Cf-fission event and/or (b) a counting event in another detector. Detection of {sup 252}Cf spontaneous fission is frequently achieved via use of a small ionization chamber in which the {sup 252}Cf is contained--in this case the timing of source emission events is random. However, one application subsequently described uses a neutron-absorbent ''shutter'' to modulate {sup 252}Cf emissions to produce a neutron source with deterministic timing. Other applications, frequently termed noise-analysis measurements, transform the time-distributions to the frequency domain. Collectively, these correlation methods use {sup 252}Cf to ''excite'' the fissile material and the response of the material is measured by an array of detectors and analyzed using standard time-correlation and/or frequency-analysis techniques. In recent years numerous advances have been made in the application of these methods to in-situ, or field measurements directed at characterizing various configurations of fissile material in operational facilities.

Mattingly, J.K.

2000-01-04

292

Correlation measurements with {sup 252}Cf to characterize fissile material  

SciTech Connect

Measurements using {sup 252}Cf as a timed source of neutrons and gammas have in recent years undergone significant maturation. These methods use {sup 252}Cf as an observable source of spontaneous fission neutrons and gammas in conjunction with one or more neutron-sensitive and/or gamma-sensitive detectors to measure the time distribution of correlated detector counts following (a) an observed {sup 252}Cf-fission event and/or (b) a counting event in another detector. Detection of {sup 252}Cf spontaneous fission is frequently achieved via use of a small ionization chamber in which the {sup 252}Cf is contained; in this case, the timing of source emission events is random. However, one application subsequently described uses a neutron-absorbent shutter to modulate {sup 252}Cf emissions to produce a neutron source with deterministic timing. Other applications, frequently termed noise-analysis measurements, transform the time distributions to the frequency domain. Collectively, these correlation methods use {sup 252}Cf to excite the fissile ray of detectors and analyzed using standard time-correlation and/or frequency-analysis techniques. In recent years, numerous advances have been made in the application of these methods to in situ or field measurements directed at characterizing various configurations of fissile material in operational facilities. Applications include reactor physics measurements, nuclear criticality safety, nondestructive analysis and nonintrusive monitoring of enrichment (or deenrichment) processes, and inventory tracking for nuclear materials control and accountability.

Mattingly, J.K.; Mihalczo, J.T.; Valentine, T.E.; Mullens, J.A.; March-Leuba, J.; Uckan, T.

2000-07-01

293

Rheology of fluids measured by correlation force spectroscopy  

NASA Astrophysics Data System (ADS)

We describe a method, correlation force spectrometry (CFS), which characterizes fluids through measurement of the correlations between the thermally stimulated vibrations of two closely spaced micrometer-scale cantilevers in fluid. We discuss a major application: measurement of the rheological properties of fluids at high frequency and high spatial resolution. Use of CFS as a rheometer is validated by comparison between experimental data and finite element modeling of the deterministic ring-down of cantilevers using the known viscosity of fluids. The data can also be accurately fitted using a harmonic oscillator model, which can be used for rapid rheometric measurements after calibration. The method is non-invasive, uses a very small amount of fluid, and has no actively moving parts. It can also be used to analyze the rheology of complex fluids. We use CFS to show that (non-Newtonian) aqueous polyethylene oxide solution can be modeled approximately by incorporating an elastic spring between the cantilevers.

Radiom, Milad; Robbins, Brian; Honig, Christopher D. F.; Walz, John Y.; Paul, Mark R.; Ducker, William A.

2012-04-01

294

Standardization of the definition and measurement of the line length and fan angle of laser line generators.  

PubMed

Three different commonly used methods of measuring the length and fan angle of a light line or a light fan produced by a laser line generator were analyzed, tested, and compared. One measurement method is proposed as the standard method, and the resultant 1/e(2) intensity fan angle is proposed as the standard parameter to describe the line generator. PMID:18285948

Sun, H

1998-07-20

295

Standardization of the Definition and Measurement of the Line Length and Fan Angle of Laser Line Generators  

NASA Astrophysics Data System (ADS)

Three different commonly used methods of measuring the length and fan angle of a light line or a light fan produced by a laser line generator were analyzed, tested, and compared. One measurement method is proposed as the standard method, and the resultant 1 e 2 intensity fan angle is proposed as the standard parameter to describe the line generator.

Sun, Haiyin

1998-07-01

296

A digital test structure for simultaneous bird's beak length and misalignment measurement in polysilicon emitter bipolar technologies  

Microsoft Academic Search

A test structure for geometrical measurements on bipolar processes is presented. Both bird's beak length and misalignment between active areas and active area openings in a polysilicon emitter bipolar technology can be obtained from a unique measurement using it. Although it is a digital structure, the accuracy can be improved by means of a fitting on the contact resistance values.

M. Ullan; M. Lozano; J. Santander; E. Lora-Tamayo; S. Nigrin; P. H. Osborne

1997-01-01

297

Reliability and accuracy of an automated tracking algorithm to measure controlled passive and active muscle fascicle length changes from ultrasound.  

PubMed

Manual tracking of muscle fascicle length changes from ultrasound images is a subjective and time-consuming process. The purpose of this study was to assess the repeatability and accuracy of an automated algorithm for tracking fascicle length changes in the medial gastrocnemius (MG) muscle during passive length changes and active contractions (isometric, concentric and eccentric) performed on a dynamometer. The freely available, automated tracking algorithm was based on the Lucas-Kanade optical flow algorithm with an affine optic flow extension, which accounts for image translation, dilation, rotation and shear between consecutive frames of an image sequence. Automated tracking was performed by three experienced assessors, and within- and between-examiner repeatability was computed using the coefficient of multiple determination (CMD). Fascicle tracking data were also compared with manual digitisation of the same image sequences, and the level of agreement between the two methods was calculated using the coefficient of multiple correlation (CMC). The CMDs across all test conditions ranged from 0.50 to 0.93 and were all above 0.98 when recomputed after the systematic error due to the estimate of the initial fascicle length on the first ultrasound frame was removed from the individual fascicle length waveforms. The automated and manual tracking approaches produced similar fascicle length waveforms, with an overall CMC of 0.88, which improved to 0.94 when the initial length offset was removed. Overall results indicate that the automated fascicle tracking algorithm was a repeatable, accurate and time-efficient method for estimating fascicle length changes of the MG muscle in controlled passive and active conditions. PMID:22235878

Gillett, Jarred G; Barrett, Rod S; Lichtwark, Glen A

2012-01-11

298

Ultrasonic Cross-Correlation Flow Measurement: Theory, Noise Contamination Mechanisms, and a Noise Mitigation Technique  

SciTech Connect

Based on past experience with ultrasonic cross-correlation flow meters in power plant environments, the presence of spatially correlated noise due to pressure waves, vibration, or sources other than transport of turbulent eddies will cause a bias in the time delays measured by the meter. Several techniques were developed to detect the existence of such correlated noise and correct for its effect at plant conditions. An analytical and experimental investigation was performed to further understand the basic physics of the noise mechanisms. The dominant error mechanisms investigated in this work were speed of sound perturbations due to pressure fluctuations and beam path length changes due to wall vibration. An analytical model was formulated which estimates the signal level of the flow meter based on the turbulent velocity field. From this model, an estimate of the system noise which would cause contamination could be determined. A test at a water tunnel facility was performed in order to evaluate the noise mechanisms. During this test, measurements were taken with and without controlled noise sources. Pressure and acceleration measurements were used to evaluate a coherent noise removal technique developed to mitigate the impact of noise in the ultrasonic cross-correlation flow measurement. The coherent noise removal technique was shown to be effective in removing noise during the water tunnel test. (authors)

Jenkins, D.M.; Lysak, P.D.; Capone, D.E. [Penn State University Applied Research Laboratory, 2001 Jefferson Davis Highway Alexandria, VA 22301 (United States); Brown, W.L. [Westinghouse, LLC (United States); Askari, V. [Advanced Measurement and Analysis Group, 2396 Dunwin Drive, Mississauga, Ontario, L5L 1J9 (Canada)

2006-07-01

299

The application of debond length measurements to examine the accuracy of composite interface properties derived from fiber pushout testing  

NASA Astrophysics Data System (ADS)

The interface failure sequence was observed during fiber pushout tests on several model composites. The pushout experiments indicated that only composites with an Esbf/Esbm ratio less than 3 and with negligible to moderate residual stresses can be expected to debond from the top. The debond length as a function of force and displacement was also measured in a polariscope for two of the model composites. The pushout data from a polyester/epoxy system that debonded from the top was fit to a shear lag solution to obtain the fiber-matrix interfacial toughness and debond length. The calculated debond length was less than the measured debond length by a nearly constant 1.5 fiber radii. A procedure was then developed to compute accurately the debond length as a function of force based on the model composite pushout data. A relatively expeditious routine involving iterative finite element analysis was applied to the progressive debonding portion of the pushout curve to compute debond length and fracture toughness. The finite element simulation included thermal and/or chemical shrinkage loads as well as the boundary conditions corresponding to the exact probe and sample support dimensions. The resulting debond lengths corresponded to within 10% to 200% of the measured debond lengths (depending on the method used to calculate the coefficient of friction) for both top and bottom debonds. Finally, an experiment was designed and constructed to perform fiber pushout tests at temperatures up to 800sp°C and in a controlled environment. Preliminary pushout tests on both a pristine and a transversely fatigued SiC/Ti-6-4 composite were conducted to assess the capabilities of this apparatus. A negligible force was required to slide the fibers in the fatigued samples at 400sp°C, indicating that the fibers were debonded by the fatigue load. The identification of progressive debonding in metal matrix composites is also discussed.

Bechel, Vernon Thomas

300

Measurement of the transverse spin correlations in the decay Z -> ?+?-  

NASA Astrophysics Data System (ADS)

For ? leptons produced in e+e- -> ?+?- interactions there are, in addition to the longitudinal spin correlations, two independent transverse spin correlations associated with the transverse (within the production plane) and normal (to the production plane) polarization components. A measurement of the transverse-transverse and transverse-normal ? spin correlations in the decay Z -> ?+?-, CTT and CTN, is presented based on the aplanarity angle of the decay products of both ? leptons. Using 80 pb-1 of data collected by ALEPH on the peak of the Z resonance, the results are CTT = 1.06 +/- 0.13 (stat) +/- 0.05 (syst), and CTN = 0.08 +/- 0.13 (stat) +/- 0.04 (syst). These values are in agreement with the Standard Model predictions, CTT = 0.99 and CTN = -0.01.

Barate, R.; Buskulic, D.; Decamp, D.; Ghez, P.; Coy, C.; Lees, J.-P.; Lucotte, A.; Minard, M.-N.; Nief, J.-Y.; Pietrzyk, B.; Casado, M. P.; Chmeissani, M.; Comas, P.; Crespo, J. M.; Delfino, M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Juste, A.; Martinez, M.; Miquel, R.; Mir, Ll. M.; Orteu, S.; Padilla, C.; Park, I. C.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Alemany, R.; Becker, U.; Bazarko, A. O.; Bright-Thomas, P.; Cattaneo, M.; Cerutti, F.; Dissertori, G.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Hansen, J. B.; Harvey, J.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Lutters, G.; Mato, P.; Minten, A.; Moneta, L.; Pacheco, A.; Pusztaszeri, J.-F.; Ranjard, F.; Rizzo, G.; Rolandi, L.; Rousseau, D.; Schlatter, D.; Schmitt, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Wachsmuth, H.; Wagner, A.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Ferdi, C.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rosnet, P.; Rossignol, J.-M.; Fearnley, T.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Rensch, B.; Wäänänen, A.; Daskalakis, G.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Zachariadou, K.; Corden, M.; Georgiopoulos, C.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Scarr, J. M.; Smith, K.; Teixeira-Dias, P.; Thompson, A. S.; Thomson, E.; Thomson, F.; Turnbull, R. M.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Schmidt, M.; Sommer, J.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Girone, M.; Goodsir, S.; Martin, E. B.; Moutoussi, A.; Nash, J.; Sedgbeer, J. K.; Spagnolo, P.; Stacey, A. M.; Williams, M. D.; Ghete, V. M.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A. P.; Bowdery, C. K.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Jones, R. W.; Sloan, T.; Williams, M. I.; Galla, A.; Giehl, I.; Greene, A. M.; Hoffmann, C.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.-G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Coyle, P.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Leroy, O.; Motsch, F.; Payre, P.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Berlich, R.; Blum, W.; Büscher, V.; Dietl, H.; Ganis, G.; Gotzhein, C.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; St. Denis, R.; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Chen, S.; Choi, Y.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Höcker, A.; Jacholkowska, A.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Nikolic, I.; Schune, M.-H.; Simion, S.; Tournefier, E.; Veillet, J.-J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciabà, A.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Venturi, A.; Verdini, P. G.; Blair, G. A.; Bryant, L. M.; Chambers, J. T.; Gao, Y.; Green, M. G.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Maley, P.; Norton, P. R.; Thompson, J. C.; Wright, A. E.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Boswell, R.; Brew, C. A. J.

1997-02-01

301

Reliability-guided digital image correlation for image deformation measurement  

SciTech Connect

A universally applicable reliability-guided digital image correlation (DIC) method is proposed for reliable image deformation measurement. The zero-mean normalized cross correlation (ZNCC) coefficient is used to identify the reliability of the point computed. The correlation calculation begins with a seed point and is then guided by the ZNCC coefficient. That means the neighbors of the point with the highest ZNCC coefficient in a queue for computed points will be processed first. Thus the calculation path is always along the most reliable direction, and possible error propagation of the conventional DIC method can be avoided. The proposed novel DIC method is universally applicable to the images with shadows, discontinuous areas, and deformation discontinuity. Two image pairs were used to evaluate the performance of the proposed technique, and the successful results clearly demonstrate its robustness and effectiveness.

Pan Bing

2009-03-10

302

One year of EARLINET correlative measurements for CALIPSO  

NASA Astrophysics Data System (ADS)

EARLINET is the European Aerosol Research Lidar Network providing systematic observations of aerosol profiling on continental scale. At present, the network includes 25 stations distributed over Europe: 10 single backscatter lidar stations, 8 Raman lidar stations with the UV Raman channel for independent measurements of aerosol extinction and backscatter, and 7 multi-wavelength Raman lidar stations for the retrieval of aerosol microphysical properties. EARLINET represents an optimal tool to validate CALIPSO lidar data and to provide the necessary information to fully exploit the data produced from that mission. In particular, aerosol extinction and lidar ratio measurements, provided by the network, will be important for the aerosol retrievals from the backscatter lidar (CALIOP) on board CALIPSO. EARLINET started correlative measurements for CALIPSO since 14 June 2006. A suitable, three-stage strategy for correlative measurements has been implemented within EARLINET on the base of the analysis of the high resolution ground track data provided by NASA. EARLINET correlative measurements are performed at stations located within 80km from the overpasses and additionally at the lidar stations which are closest to the actually overpassed site. Moreover, if a multi-wavelength Raman lidar station is overpassed then also the next closest multi-wavelength Raman lidar station performs a measurement. Each correlative measurement lasts for a minimum of 1 hour centered around the overpass time; longer records of measurements are performed for special case studies (Saharan dust layers, forest fires, long range transport, etc.). Further information from backtrajectory analysis are used to quantitatively study comparisons between CALIPSO and EARLINET observations. EARLINET performed more than 1000 correlative observations during the first operational year of CALIPSO (June 2006 - June 2007), first results in terms of comparisons between EARLINET and available CALIPSO products will be presented. ACKNOWLEDGMENTS The financial support by the European Commission under grant RICA-025991 is gratefully acknowledged. The authors also thank the German Weather Service for the air mass backtrajectory analysis and the CALIPSO team of the NASA Langley Research Center for the provision of the CALIPSO high resolution ground track data. CALIPSO data were obtained from the NASA Langley Research Center Atmospheric Science Data Center.

Pappalardo, G.

2007-12-01

303

Measurement of Length of Hyperdense MCA Sign in Acute Ischemic Stroke Predicts Disappearance after IV tPA.  

PubMed

BACKGROUND: We sought to assess the hypothesis that length and volumes of middle cerebral artery (MCA) thrombus were associated with disappearance of the hyperdense middle cerebral artery sign (HMCAS) in acute ischemic stroke. METHODS: This is a retrospective cohort study of acute ischemic stroke patients with MCA occlusion admitted to the University Hospital in Canada. The length and volumes of the HMCAS was measured on the plain CT by placing CTA images (CTA source images or MIP images) side-by-side. RESULTS: Seventy-six patients with acute stroke having HMCAS on noncontrast CT (NCCT) with M1 MCA occlusion confirmed by CT angiography or digital subtraction angiography and received tPA. The treatments received were: IV tPA 41(53.9%) and endovascular treatment ± IV tPA 35 (46.1%). In the IV tPA group, the rate of disappearance varied depending on the baseline HMCAS length. Short length HMCAS (<10 mm) disappeared in 6/7 (85.7%) (P < .001). Medium length HMCAS (10-20 mm) disappeared in 9/24 (37.5%). No cases of long length HMCAS (>20 mm) disappeared (0/10) (P= .05). Rate of disappearance of HMCAS was found to be volume dependent (P < .002). CONCLUSION: HMCAS length >10 mm infrequently disappears with IV tPA suggesting a potential need for ancillary therapy in this group. PMID:23316960

Shobha, Nandavar; Bal, Simerpreet; Boyko, Matthew; Kroshus, Eric; Menon, Bijoy K; Bhatia, Rohit; Sohn, Sung-Il; Kumarpillai, Gopukumar; Kosior, Jayme; Hill, Michael D; Demchuk, Andrew M

2013-01-14

304

Assessment of three dimensional quantitative coronary analysis by using rotational angiography for measurement of vessel length and diameter.  

PubMed

The aim of the study was to assess the accuracy of the three-dimensional (3D) quantitative coronary analysis (QCA) system by comparing with that of intravascular ultrasound (IVUS) QCA and two-dimensional (2D) QCA. 3D QCA, 2D QCA and IVUS QCA were performed in 45 vessel segments. The obtained values for the branch to branch segment vessel length and the proximal part of the segment vessel's lumen diameter were measured. Inter-technique agreement was analyzed using paired sample t-test and Bland-Altman analysis. No differences were found in vessel lengths taken by 3D QCA and IVUS QCA (mean difference: 0.29 ± 1.06 mm, P = 0.07). When compared with IVUS QCA, 2D QCA underestimated vessel length (mean difference: -1.78 ± 2.55, P < 0.001). Bland-Altman analysis showed close agreement and a small bias between 3D QCA and IVUS QCA in the measurement of vessel length. The vessel lumen diameter measurements by 2D QCA and 3D QCA were significantly lower than that by IVUS QCA (mean difference: -0.64 ± 0.69, P < 0.001; -0.56 ± 0.52, P < 0.001 respectively). Rotational angiography with 3D reconstruction can provide a more accurate vessel length measurement, whereas 2D and 3D QCA underestimated the vessel lumen diameter compared with IVUS QCA. PMID:22179945

Lee, Jin Bae; Chang, Sung Gug; Kim, So Yeon; Lee, Young Soo; Ryu, Jae Kean; Choi, Ji Yong; Kim, Kee Sik; Park, Jae Sik

2011-12-18

305

Quantitative Evaluation of Cross-Correlation Between Two Finite-Length Time Series with Applications to Single-Molecule FRET  

PubMed Central

The statistical properties of the cross-correlation between two time series has been studied. An analytical expression for the cross-correlation function’s variance has been derived. Based on these results, a statistically robust method has been proposed to detect the existence and determine the direction of cross-correlation between two time series. The proposed method has been characterized by computer simulations. Applications to single-molecule fluorescence spectroscopy are discussed. The results may also find immediate applications in fluorescence correlation spectroscopy (FCS) and its variants.

Hanson, Jeffery A.; Yang, Haw

2009-01-01

306

Correlation of chain length compatibility and surface properties of mixed foaming agents with fluid displacement efficiency and effective air mobility in porous media  

SciTech Connect

The effects of chain length compatibility and surface properties of mixed foaming agents on fluid displacement efficiency and effective air mobility in porous media were investigated. Sodium dodecyl sulfate (C/sub 12/H/sub 25/SO/sub 4/Na) and various alkyl alcohols (e.g., C/sub 8/OH,C/sub 10/OH,C/sub 12/OH,C/sub 14/OH, and C/sub 16/OH) were used as mixed foaming agents. It was observed that the surface properties of surfactant solutions and flow behavior of foams through porous media were influenced by the chain length compatibility of the surfactant molecules. The increase in the length of porous media improved fluid displacement efficiency while breakthrough time per unit length decreased slightly with increase in the length of porous media. For mixed surfactant systems, a minimum in surface tension, a maximum in surface viscosity, a minimum in bubble size, a maximum in breakthrough time, a maximum in fluid displacement efficiency, and a minimum in effective air mobility were observed when the two components of the surfactant system had the same chain length. These results indicate that the surface properties of foaming solutions and molecular packing at interfaces exhibit a striking correlation with breakthrough time, fluid displacement efficiency, and effective air mobility in porous media.

Sharma, M.K.; Bringham, W.E.; Shah, D.O.

1984-05-01

307

Used digital speckle correlation method to measure vibration  

NASA Astrophysics Data System (ADS)

Used digital speckle correlation method (DSCM) to measure is researched. The experiment is designed and the laser irradiates a PZT which is driven by some signal to obtain the dynamic speckle patterns. The dynamic speckle patterns are shot by CCD, then the DSCM is used to process the sequential images and also the experiment is simulated. The movement of reflection target is controlled by PZT which is driven by the different model signal. When the reflection target is moving, the dynamic speckle patterns are shot by CCD, the sequential images are stored in computer through an image board. Then the digital speckle correlation method is used to process the sequential images. There are three output parameters after the images correlation calculation: (xi ,yi) and ? that represent for position and moving direction of the object, Initial (xi ,yi) is (0,0). (?xi , ?yi) represents pixel difference in coordinates of two adjacent images. ? is the angle specifying the direction of the object's motion relative to the x-axis: ??[00,900]. Varying the speed of the aluminum plate, variant values of (?xi ,?i) are obtained and varying the direction of numeric control caterpillar track, variant values of ? were obtained. From the obtained displacement and the collected frequency, the vibration frequency was obtained. The experimental results show the DSCM can confirm the frequency and displacement of vibration, and have a good agreement with the simulation results, and the results show the digital speckle correlation method can be used to measure vibation.

Yan, Haitao; Zhen, Zhiqiang; Tang, Zhengxin

2009-11-01

308

Performance of a correlator filter in betatron tune measurements and damping on the NSLS booster  

SciTech Connect

A ''compensated correlator filter'', described by Kramer, et al. has been used for measurement and damping of betatron oscillations in the NSLS booster. The filter consists of a zero-degree power splitter, a 180-degree splitter, a length of 7/8'' air dielectric coaxial cable, and a short length of RG-58 cable. Connected to a beam position monitor, the output of the filter is proportional to the difference in transverse position of each bunch on subsequent turns. The useful bandwidth of the filter for damping rigid bunch oscillations extends from 10 MHz to 250 MHz, in contrast with the gigahertz bandwidth requirements for stochastic cooling, for which the filter was originally proposed. Attenuation of all rotation harmonics in this bandwidth is 40 to 60 dB.

Galayda, J.

1985-01-01

309

Precise Measurement of Diffusion Coefficients using Scanning Fluorescence Correlation Spectroscopy  

Microsoft Academic Search

We have implemented scanning fluorescence correlation spectroscopy (sFCS) for precise determination of diffusion coefficients of fluorescent molecules in solution. The measurement volume where the molecules are excited, and from which the fluorescence is detected, was scanned in a circle with radius comparable to its size at frequencies 0.5–2kHz. The scan radius R, determined with high accuracy by careful calibration, provides

Zden?k Petrášek; Petra Schwille

2008-01-01

310

Measurement of vegetable growth by laser-speckle correlation  

NASA Astrophysics Data System (ADS)

We have measured the growth of vegetable leaves in real-time by means of digital speckle correlation to detect speckle displacement caused by the growth. We employed two optical configurations, the first for detecting strain component by a pair of CCDs and the second for detecting in-plane translation by a single CCD. We could clearly observe the influence of white light irradiation on the growth rate.

Kobayashi, Koichi; Kadono, Hirofumi; Yamaguchi, Ichirou

2010-09-01

311

Correlates of objectively measured physical activity in preadolescent youth  

Microsoft Academic Search

Objective: The purpose of this study was to identify the psychosocial and environmental correlates of objectively measured physical activity behavior in a diverse sample of sixth-grade students.Design: Cross-sectional.Participants and Setting: One hundred ninety-eight sixth-grade students from 4 public middle schools in Columbia, South Carolina. The study group was 52.0% female, 55.1% African-American, with a mean age of 11.4 ± 0.6

Stewart G Trost; Russell R Pate; Dianne S Ward; Ruth Saunders; William Riner

1999-01-01

312

Applications of correlation and quantum entanglement to optical measurement  

NASA Astrophysics Data System (ADS)

Entangled-photon methods have led to a number of new techniques and effects in optical imaging, communication, and measurement. These range from dispersion cancelation techniques to ghost imaging and quantum lithography. Although all of these methods made use of entangled quantum systems in their original forms, in some cases it has since been found that similar effects can be reproduced with the entangled-photon pairs replaced by classically correlated beams. The goal in this thesis is to develop a cluster of new methods using entangled photon pairs or classically-correlated light beams for applications in optical imaging and measurement. In each of these methods, the photons are detected pairwise by two detectors connected via a coincidence circuit. Thus, the devices to he described have correlated or entangled biphoton states, rather than individual photons, as their basic operating unit. The major theme running through the proposed applications is that correlation and entanglement allow unprecedented control over the phases of these pairs. This control allows useful new effects that are impossible in devices whose operation depends on the detection of individual photons. The applications discussed fall into three general categories. First we show that by arranging for pairwise phase cancelations we may reduce or eliminate a number of distorting influences, allowing improved image quality and reduced noise. Within this category, we will concentrate on the cancelation of optical turbulence caused by passage of light through fluids and on cancelation of static abberations introduced by passage through an optical system. The second category of application is microscopy. Two new devices (the correlation confocal microscope and twin-photon microscope) are described which make use of pairwise phase correlations to improve lateral resolution in confocal microscopy. These differ from each other and from the standard two-photon microscope by the manner in which the correlation is imposed. Finally, the third category of application involves the characterization of periodic structures on the surfaces of materials. Two techniques (quantum scatterometry and holographic scatterometry) are proposed to enhance nonimaging surface structure characterization by means of correlated photon methods.

Simon, David S.

313

Neural Correlates of Temporal Auditory Processing in Developmental Dyslexia during German Vowel Length Discrimination: An fMRI Study  

ERIC Educational Resources Information Center

|This fMRI study investigated phonological vs. auditory temporal processing in developmental dyslexia by means of a German vowel length discrimination paradigm (Groth, Lachmann, Riecker, Muthmann, & Steinbrink, 2011). Behavioral and fMRI data were collected from dyslexics and controls while performing same-different judgments of vowel duration in…

Steinbrink, Claudia; Groth, Katarina; Lachmann, Thomas; Riecker, Axel

2012-01-01

314

A Strong Correlation Exists between the Distribution of Retinal Ganglion Cells and Nose Length in the Dog  

Microsoft Academic Search

The domestic dog, Canis lupus familiaris, is a subspecies of the gray wolf, Canis lupus, with almost identical mitochondrial DNA. The dog is the most diverse species on earth, with skull length varying between 7 and 28 cm whereas the wolf skull is around 30 cm long. However, eye size in dogs does not appear to vary as much. For

Paul McGreevy; Tanya D. Grassi; Alison M. Harman

2004-01-01

315

Neural Correlates of Temporal Auditory Processing in Developmental Dyslexia during German Vowel Length Discrimination: An fMRI Study  

ERIC Educational Resources Information Center

This fMRI study investigated phonological vs. auditory temporal processing in developmental dyslexia by means of a German vowel length discrimination paradigm (Groth, Lachmann, Riecker, Muthmann, & Steinbrink, 2011). Behavioral and fMRI data were collected from dyslexics and controls while performing same-different judgments of vowel duration in…

Steinbrink, Claudia; Groth, Katarina; Lachmann, Thomas; Riecker, Axel

2012-01-01

316

DEVELOPMENT OF ALGORITHM FOR THE GENERATION AND CORRELATION STUDY OF MAXIMAL LENGTH SEQUENCES FOR APPLICABILITIES IN CDMA MOBILE COMMUNICATION SYSTEMS  

Microsoft Academic Search

With the advancement of VLSI technology spread spectrum CDMA system has now come up as a highly emerging digital technology for 3G and beyond mobile systems. In this system the basic hardware involves maximal length pn sequence or m-sequence generated by a Linear Feedback Shift Register (LFSR) provided this LFSR is represented by a primitive polynomial. In this paper we

S. Chattopadhyay

317

A comparison of methods for converting rhizotron root length measurements into estimates of root mass production per unit ground area  

Microsoft Academic Search

Rhizotrons provide valuable information about plant root production, but measurements are usually made in units of root length\\u000a per unit surface area of observation window surface. These measurement units are not easily comparable to above-ground plant\\u000a growth. To address this deficiency, several techniques have been developed to convert rhizotron measurement units into root\\u000a mass production per unit ground area. In

D. B. Metcalfe; P. Meir; M. Williams

2007-01-01

318

Correlation of radiographic and pedobarograph measurements in planovalgus foot deformity.  

PubMed

Planovalgus foot deformity is common in children with cerebral palsy. Several pathologies contribute to the deformity. It begins with the lateral displacement of the navicular and the talar head becomes uncovered and prominent in the medial side of the midfoot. The purpose of this study was to assess the correlation between the radiographic and the pedobarographic measurements and the ability to predict foot pressure components using radiographic measurement. The patient sample included 43 patients with cerebral palsy who were ambulatory and had planovalgus foot deformity (76 feet). Medial midfoot pressure showed correlation with talonavicular uncoverage index, talonavicular angle, medial arch angle, Meary angle, and lateral talocalcaneal angle. Heel impulse showed negative correlation with talonavicular uncoverage index and talonavicular angle. Simple linear regression was used to assess the relationship between radiographic and foot pressure component measurements. For every unit change in talonavicular uncoverage index, the predicted value of medial midfoot pressure was [9.9+27 (talonavicular uncoverage index)]. This equation accounted for 17.9% of the changes in the medial midfoot pressure. Tibial foot angle and maximum knee extension also contributed to the heel impulse. The radiographic indices of the planovalgus foot can explain the changes in some foot pressure components. PMID:22525421

Kadhim, Muayad; Holmes, Laurens; Miller, Freeman

2012-04-22

319

Measurement of correlated b quark cross sections at CDF  

SciTech Connect

Using data collected during the 1992--93 collider run at Fermilab, CDF has made measurements of correlated b quark cross section where one b is detected from a muon from semileptonic decay and the second b is detected with secondary vertex techniques. We report on measurements of the cross section as a function of the momentum of the second b and as a function of the azimuthal separation of the two b quarks, for transverse momentum of the initial b quark greater than 15 GeV. Results are compared to QCD predictions.

Gerdes, D.; CDF Collaboration

1994-09-01

320

Measure of the correlation between brain activities: a methodological approach.  

PubMed

This paper is a short review of the work done on methods of measuring nerve activity. 1) It is proposed that physiologically meaningful measures of mass activities should have the character of time averages. The advantages of continuous integration are discussed. 2) For a comparison of the mass activities from different structures the method of the ongoing cross-correlation coefficient is proposed. The properties of the method are discussed and some preliminary results are reported showing its usefulness in the investigation of the so-called steady state activities. PMID:7138185

Arduini, A

1982-05-01

321

Direct measurement of DNA molecular length in solution using optical tweezers: detection of looping due to binding protein interactions.  

PubMed

DNA looping is caused by the interaction between DNA binding proteins located at separate positions on a DNA molecule and may play an important role in transcription regulation. We have developed a system to stretch single DNA molecules and to measure changes in molecular length. DNA molecules were prepared and 5' end-labeled by PCR amplification. Two beads and the intervening DNA molecule were trapped and manipulated independently with dual trap optical tweezers. The trapped DNA molecule was then stretched and the extension (the distance between the two beads) was measured. The extension at the specific tension force of 30 pN was calculated and used as a molecular length. The molecular length was found to be proportional to the base pair number. The rise per residue was calculated to be 3.31 +/- 0.05 A. The length measurement was applied to DNA fragments containing GC box sequences at two different locations separated by a distance of 2.428 kbp. The addition of GC box binding transcription factor Sp1 shortened the molecular length, suggesting DNA looping forms as a result of interaction between transcription factors. PMID:9463890

Sakata-Sogawa, K; Kurachi, M; Sogawa, K; Fujii-Kuriyama, Y; Tashiro, H

1998-01-01

322

Correlated response in growth and body measurements accompanying selection for milk yield in Jerseys.  

PubMed

Growth and body measurements from a long-term selection project were analyzed to determine correlated responses to single-trait selection for milk yield. Data were from 1056 daughters (765 selection, 291 control) of 37 bulls (17 selection, 20 control) of 37 bulls (17 selection, 20 control) and included BW and measures of heart girth, chest depth, wither height, and length from withers to pins and from withers to hooks taken at 6 mo, 15 mo, first calving, end of first lactation, and maturity. Other data were birth weight, change in measurements and weights from first calving to end of first lactation, monthly rate of gain from 1 to 13 mo of age, and age reaching breeding weight (250 kg). Principal component scores were calculated from standardized measurements at each age. The first three principal components has meaning (size, length vs. girth, and height vs. girth). All analyses used linear mixed models with fixed effects of genetic group, generation within group, year-season of birth or calving, parity of dam, and birth status (multiple or single birth). Sires were assumed to be random and nested within genetic group. Mean squares for sires was used to test for group differences. Generation did not differ in any analysis and was removed from all models. Selection cows were heavier, larger in some measurements, and had greater overall size at 6 mo of age. Selection cows had greater monthly rate of gain and attained breeding weight at an earlier age. Genetic groups did not differ for any other measurement or weight. Control cows gained more weight and increased more in some measurements between first calving and end of first lactation. Selection for milk yield did not result in an undesirable correlated response in an growth or body measurement. PMID:1541738

Bonczek, R R; Richardson, D O; Moore, E D; Miller, R H; Owen, J R; Dowlen, H H; Bell, B R

1992-01-01

323

Multiple length and time scales of dynamic heterogeneities in model glass-forming liquids: a systematic analysis of multi-point and multi-time correlations.  

PubMed

We report an extensive and systematic investigation of the multi-point and multi-time correlation functions to reveal the spatio-temporal structures of dynamic heterogeneities in glass-forming liquids. Molecular dynamics simulations are carried out for the supercooled states of various prototype models of glass-forming liquids such as binary Kob-Andersen, Wahnstro?m, soft-sphere, and network-forming liquids. While the first three models act as fragile liquids exhibiting super-Arrhenius temperature dependence in their relaxation times, the last is a strong glass-former exhibiting Arrhenius behavior. First, we quantify the length scale of the dynamic heterogeneities utilizing the four-point correlation function. The growth of the dynamic length scale with decreasing temperature is characterized by various scaling relations that are analogous to the critical phenomena. We also examine how the growth of the length scale depends upon the model employed. Second, the four-point correlation function is extended to a three-time correlation function to characterize the temporal structures of the dynamic heterogeneities based on our previous studies [K. Kim and S. Saito, Phys. Rev. E 79, 060501(R) (2009); and J. Chem. Phys. 133, 044511 (2010)]. We provide comprehensive numerical results obtained from the three-time correlation function for the above models. From these calculations, we examine the time scale of the dynamic heterogeneities and determine the associated lifetime in a consistent and systematic way. Our results indicate that the lifetime of the dynamical heterogeneities becomes much longer than the ?-relaxation time determined from a two-point correlation function in fragile liquids. The decoupling between the two time scales is remarkable, particularly in supercooled states, and the time scales differ by more than an order of magnitude in a more fragile liquid. In contrast, the lifetime is shorter than the ?-relaxation time in tetrahedral network-forming strong liquid, even at lower temperatures. PMID:23556757

Kim, Kang; Saito, Shinji

2013-03-28

324

Direct measurement of transverse coherence length of hard X rays from interference fringes  

PubMed

We propose a simple interferometric technique for hard x-ray spatial coherence characterization, recording a Fresnel interference pattern produced by a round fiber or a slit. We have derived analytical formulas that give a direct relation between a visibility of interference fringes and either the source size or the transverse coherence length. The technique is well suited to third-generation synchrotron radiation sources and was experimentally applied to determine the spatial coherence length and the source size at the European Synchrotron Radiation Facility. PMID:10991223

Kohn; Snigireva; Snigirev

2000-09-25

325

Correlative ground-based lidar measurements for LITE  

NASA Astrophysics Data System (ADS)

The lidar in-space technology experiment (LITE) has been developed at the NASA Langley Research Center to fly on the Space Shuttle and demonstrate the utility of lidar systems in space. An extensive correlative measurements campaign to validate LITE measurements with coincident measurements made with reliable ground-based and balloon-borne sensors was carried out both in Napoli and Potenza in the period September 10-19, 1994. The lidar in Napoli is based on a Xe:F excimer laser (351 nm), while the lidar in Potenza is based on a Nd:YAG laser operating both on the 2nd (532 nm) and 3rd (355 nm) harmonic. During this intense campaign we performed both elastic and Raman measurements for molecular nitrogen. Solar irradiance spectra at ground level were measured by an Optical Spectra Analyzer in the spectral region 0.4-1.1 micrometers , obtaining both columnar water vapor and aerosol load. Aerosol backscattering data will be presented. Elastic and nitrogen Raman signals are used for measuring atmospheric transmissivity. Finally the density and temperature profiles obtained from the simultaneous measurement of the elastic and the N2 Raman signal will be presented. Simultaneous radiosonde measurements of temperature, pressure, and relative humidity will be used to compare lidar data.

Cuomo, Vincenzo; Di Girolamo, P.; Esposito, F.; Pappalardo, Gelsomina; Romano, F.; Serio, Carmine; Spinelli, N.; Armenante, M.; Bartoli, B.; Berardi, V.; Bruzzese, Riccardo; Bellecci, C.; Caputi, G. E.; De Donato, F.; Gaudio, P.; Valentini, Mario

1995-09-01

326

Tibiofemoral centroid velocity correlates more consistently with cartilage damage than does contact path length in two ovine models of stifle injury.  

PubMed

Anterior cruciate ligament (ACL) rupture and/or meniscal injury are known risk factors for post-traumatic osteoarthritis. We tested the hypothesis that increasingly abnormal tibiofemoral centroid path lengths and velocities would correlate with the severity of cartilage damage in injured sheep. Six sheep underwent combined ACL/medial collateral ligament transection (ACL/MCLx), five complete lateral meniscectomy (Mx), and four sham arthrotomy (Sham). Weighted centroids were used to estimate in vivo tibiofemoral cartilage contact path length during stance and the velocity of relative motion. Cartilage morphology was graded at dissection. Ligament transection significantly elongated plateau centroid path lengths and velocities, whereas condyle paths and velocities were reduced. Differences between plateau and femoral velocities (relative centroid velocity) were increased up to 10-fold over baseline values in the medial compartment. Reductions in Mx lateral compartment paths were significantly different from ACL/MCLx paths, but not relative to baseline or Sham values. Importantly, only centroid velocities consistently correlated with cartilage damage in either injury model, suggesting that while path length is valuable in detecting changes in the envelope of joint motion, it may average out meaningful peaks in the rate of relative motion that more closely relate to the mechanisms that might be damaging articular cartilage in these models. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1745-1756, 2013. PMID:23832294

Beveridge, Jillian E; Heard, Bryan J; Shrive, Nigel G; Frank, Cyril B

2013-07-06

327

The role of multiparticle correlations and Cooper pairing in the formation of molecules in an ultracold gas of Fermi atoms with a negative scattering length  

SciTech Connect

The influence of multiparticle correlation effects and Cooper pairing in an ultracold Fermi gas with a negative scattering length on the formation rate of molecules is investigated. Cooper pairing is shown to cause the formation rate of molecules to increase, as distinct from the influence of Bose-Einstein condensation in a Bose gas on this rate. This trend is retained in the entire range of temperatures below the critical one.

Babichenko, V. S., E-mail: vsbabichenko@hotmail.com; Kagan, Yu. [National Research Centre Kurchatov Institute (Russian Federation)

2012-11-15

328

Correlation between shape resonance energies and C-C bond length in carbon-containing molecules: Elastic electron scattering and carbon K-shell excitation by photons.  

National Technical Information Service (NTIS)

We document the correlation of shape resonance energies resulting from (i) elastic electron scattering and (ii) carbon K-shell excitation with ic bond order (C-C bond length) for C(sub 2)H(sub 2), C(sub 2)H(sub 4), C(sub 2)H(sub 6), C(sub 3)H(sub 8), C(su...

M. Kimura

1994-01-01

329

Photoacoustic correlation technique for low-speed flow measurement.  

PubMed

A photoacoustic correlation spectroscopy (PACS) technique was proposed for the first time. This technique is inspired by its optical counterpart-the fluorescence correlation spectroscopy (FCS), which is widely used in the characterization of the dynamics of fluorescent species. The fluorescence intensity is measured in FCS while the acoustic signals are detected in PACS. To proof of concept, we demonstrated the flow measurement of light-absorbing beads probed by a pulsed laser. A PACS system with temporal resolution of 0.8 sec was built. Polymer microring resonators were used to detect the photoacoustic signals, which were then signal processed and used to obtain the autocorrelation curves. Flow speeds ranging from 249 to 15.1 ?m/s with corresponding flow time from 4.42 to 72.5 sec were measured. The capability of low-speed flow measurement can potentially be used for detecting blood flow in relatively deep capillaries in biological tissues. Moreover, similar to FCS, PACS may have many potential applications in studying the dynamics of photoacoustic beads. PMID:20689645

Chen, Sung-Liang; Ling, Tao; Huang, Sheng-Wen; Baac, Hyoung Won; Chang, Yu-Chung; Guo, L Jay

2010-02-11

330

Photoacoustic correlation technique for low-speed flow measurement  

PubMed Central

A photoacoustic correlation spectroscopy (PACS) technique was proposed for the first time. This technique is inspired by its optical counterpart—the fluorescence correlation spectroscopy (FCS), which is widely used in the characterization of the dynamics of fluorescent species. The fluorescence intensity is measured in FCS while the acoustic signals are detected in PACS. To proof of concept, we demonstrated the flow measurement of light-absorbing beads probed by a pulsed laser. A PACS system with temporal resolution of 0.8 sec was built. Polymer microring resonators were used to detect the photoacoustic signals, which were then signal processed and used to obtain the autocorrelation curves. Flow speeds ranging from 249 to 15.1 ?m/s with corresponding flow time from 4.42 to 72.5 sec were measured. The capability of low-speed flow measurement can potentially be used for detecting blood flow in relatively deep capillaries in biological tissues. Moreover, similar to FCS, PACS may have many potential applications in studying the dynamics of photoacoustic beads.

Chen, Sung-Liang; Ling, Tao; Huang, Sheng-Wen; Baac, Hyoung Won; Chang, Yu-Chung; Guo, L. Jay

2010-01-01

331

Correlation between shape resonance energies and C-C bond length in carbon-containing molecules: Elastic electron scattering and carbon K-shell excitation by photons  

SciTech Connect

We document the correlation of shape resonance energies resulting from (i) elastic electron scattering and (ii) carbon K-shell excitation with ic bond order (C-C bond length) for C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, C{sub 2}H{sub 6}, C{sub 3}H{sub 8}, C{sub 4}H{sub 10}, and C{sub 6}H{sub 6}. A relationship between K-shell {sigma} resonances and bond length was experimentally pointed out previously. These correlations are qualitatively interpreted to indicate that as molecular size increases (or as bond length increases), the configuration space available for valence electrons increases, reducing energy levels rather uniformly and mowing these correlations to emerge. The similarity of shape resonances in electron scattering and photoexcitation occurs because major events in the resonances take place slightly outside the molecular field and receive little influence from the inner structure of the molecule.

Kimura, Mineo [Argonne National Lab., IL (United States)]|[Rice Univ., Houston, TX (United States). Dept. of Physics

1994-06-01

332

Importance of Independent Measurement of Width and Length of Lateral Meniscus During Preoperative Sizing for Meniscal Allograft Transplantation  

Microsoft Academic Search

Background: Successful meniscus transplantation depends on an accurate sizing of the meniscal allograft. Although accurate sizing of the meniscal allograft is crucial during meniscus transplantation, the accuracy of meniscal measurement methods is still in debate.Purpose: This study was undertaken to evaluate the relationship between the width and length of the lateral meniscus. These anatomic dimensions were also evaluated in the

Jung-Ro Yoon; Taik-Sun Kim; Joon-Ho Wang; Ho-Hyun Yun; Hyungtae Lim; Jae-Hyuk Yang

2011-01-01

333

Development of a Microcircuit Grid Technique for Automated Crack Length Measurement for Fatigue Testing at Elevated Temperature.  

National Technical Information Service (NTIS)

A microcircuit grid technique was investigated and used to measure crack lengths in fatigue crack growth test specimens of an aluminum alloy (7075-T6) at room temperature and a nickel-based superalloy (Inconel 718) at 650 C as part of a Phase I SBIR progr...

A. V. Virkar D. K. Shetty K. Stuffle R. A. Cutler

1988-01-01

334

Real-time motion measurement hardware: Phase correlation unit  

NASA Astrophysics Data System (ADS)

One of the most important techniques with the highest potential for increasing the quality and scope of future television systems and equipment is motion compensation. Motion compensation relies on the accurate determination of the velocities of objects in the image plane so that any movement can be accounted for in subsequent image processing operations. Experimental equipment designed and built at BBC Research Department for undertaking such velocity measurement is described; it forms one part of a complete real-time video motion estimation system and is based on the phase correlation method of motion vector extraction. The equipment described implements the phase correlation itself. The design of the equipment is discussed and some results obtained from it are presented.

Dabner, S. C.

335

Automated diameter measurement of vasomotion by cross-correlation.  

PubMed

A method to measure automatically and continuously blood vessel diameters in the microcirculation is proposed. After imaging by video microscopy, the window of a video photometric analyzer scans the vessel of interest providing a continuous readout of the optical density along a selected direction in the video scene. The signal is differentiated to find the locations of the vessel walls and is cross-correlated to give their positions in relation to each other, thus mimicking electronically what the eye does in the image-shearing technique. Accuracy is limited to widths between twelve and sixty pixels on the video screen because of restrictions in the precision possible in tracking the peak of maximum cross-correlation. The scanning frequency was 1.2 Hz. Therefore, the method is suitable for quantifying the patterns of vasomotion. PMID:3988455

Kaufman, A G; Intaglietta, M

1985-01-01

336

Directional correlation measurements for gamma transitions in 127Te  

NASA Astrophysics Data System (ADS)

The directional correlation of coincident ? transitions in 127Te has been measured following the ?- decay of 127Sb (T1/2=3.9 d) using Ge(Li)-Ge(Li) and Ge(Li)-NaI(T1) gamma spectrometers. Measurements have been carried out for 14 gamma cascades resulting in the determination of multipole mixing ratios ?(E2/M1) for 15 ? transitions. The present results permitted a definite spin assignment of (7/2) for the 785 keV level and confirmation of several previous assignments to other levels in 127Te. The g factor of the 340 keV ((9/2)-) level has also been measured using the integral perturbed angular correlation method in the hyperfine magnetic field of a Te in Ni matrix. The results of the g factor as well as the mixing ratio for the 252 keV ((9/2)--->(11/2)-) transition support the earlier interpretation of this state as an anomalous coupling state.

de Souza, Maristela Olzon M. D.; Saxena, R. N.

1985-02-01

337

Transvaginal ultrasonographic measurement of cervical length as a predictor of preterm birth: a systematic review with meta-analysis.  

PubMed

The advent of effective interventions to prevent preterm delivery such as 17 hydroxyprogesterone and cerclage serve as an impetus to determine whether routine second trimester transvaginal cervical length screening can identify which women would benefit from these therapies. A systematic review was conducted, 957 abstracts were screened, 234 articles underwent full-text review, and 23 studies were included in the final analysis including 26,792 women. Data from relevant studies were pooled to produce summary estimates of sensitivity, specificity, and likelihood ratios using a random effects model. The ideal criteria of transvaginal cervical length measurements to predict preterm delivery are discussed. PMID:21084959

Domin, Christannah M; Smith, Erica J; Terplan, Mishka

2010-12-01

338

Quantum dots thermal stability improves simultaneous phenotype-specific telomere length measurement by FISH-flow cytometry  

PubMed Central

Telomere length analysis has been greatly simplified by the quantitative flow cytometry technique flow-FISH. In this method, a fluorescein-labeled synthetic oligonucleotide complementary to the telomere terminal repeat sequence is hybridized to the telomere sequence and the resulting fluorescence measured by flow cytometry. This technique has supplanted the traditional laborious Southern blot telomere length measurement techniques in many laboratories, and allows single cell analysis of telomere length in high-throughput sample formats. Nevertheless, the harsh conditions required for telomere probe annealing (82°C) has made it difficult to successfully combine this technique with simultaneous immunolabeling. Most traditional organic fluorescent probes (i.e. fluorescein, phycoerythrin, etc.) have limited thermal stability and do not survive the high-temperature annealing process, despite efforts to covalently crosslink the antigen-antibody-fluorophore complex. This loss of probe fluorescence has made it difficult to measure flow-FISH in complex lymphocyte populations, and has generally forced investigators to use fluorescent-activated cell sorting to pre-separate their populations, a laborious technique that requires prohibitively large numbers of cells. In this study, we have substituted quantum dots (nanoparticles) for traditional fluorophores in FISH-flow. Quantum dots were demonstrated to possess much greater thermal stability than traditional low molecular weight and phycobiliprotein fluorophores. Quantum dot antibody conjugates directed against monocyte and T cell antigens were found to retain most of their fluorescence following the high-temperature annealing step, allowing simultaneous fluorescent immunophenotyping and telomere length measurement. Since quantum dots have very narrow emission bandwidths, we were able to analyze multiple quantum dot-antibody conjugates (Qdot 605, 655 and 705) simultaneously with FISH-flow measurement to assess the age-associated decline in telomere length in both human monocytes and T cell subsets. With quantum dot immunolabeling, the mean decrease rate in telomere length for CD4+ cells was calculated at 41.8bp/year, very close to previously reported values using traditional flow-FISH and Southern blotting. This modification to the traditional flow-FISH technique should therefore allow simultaneous fluorescent immunophenotyping and telomere length measurement, permitting complex cell subset-specific analysis in small numbers of cells without the requirement for prior cell sorting.

Kapoor, Veena; Hakim, Fran T; Rehman, Najibah; Gress, Ronald E; Telford, William G

2009-01-01

339

Measurement and analysis of the turbulent length scales in jet flows  

NASA Astrophysics Data System (ADS)

The characteristic length and time scales of turbulence are reported in some detail for jet flows. The objective of the work is to determine the frequency dependence of these two-point turbulent properties, which are used to model the sources necessary for noise prediction using the acoustic analogy approach. A range of jet flow conditions for single and co-axial configurations are considered so that the effect of Mach number, temperature ratio and nozzle geometry is examined. The frequency dependence of both the fixed and moving frame length scales and the convection velocities for both the turbulence and the Reynolds stress are derived using a two-point complex coherence function. At higher frequencies, the integral scales are found to be strongly isotropic and inversely proportional to the Strouhal number. A frequency-dependent Taylor scale is derived and shown to agree well with the experimental results at the higher frequencies.

Kerhervé, F.; Fitzpatrick, J.

2011-03-01

340

Structural length-scale sensitivities of reflectance measurements in continuous random media under the Born approximation.  

PubMed

Which range of structures contributes to light scattering in a continuous random media, such as biological tissue? In this Letter, we present a model to study the structural length-scale sensitivity of scattering in continuous random media under the Born approximation. The scattering coefficient ?s, backscattering coefficient ?b, anisotropy factor g, and reduced scattering coefficient ?s* as well as the shape of the spatial reflectance profile are calculated under this model. For media with a biologically relevant Henyey-Greenstein phase function with g?0.93 at wavelength ?=633??nm, we report that ?s* is sensitive to structural length-scales from 46.9 nm to 2.07 ?m (i.e., ?/13 to 3?), ?b is sensitive from 26.7 to 320 nm (i.e., ?/24 to ?/2), and the spatial reflectance profile is sensitive from 30.8 nm to 2.71 ?m (i.e., ?/21 to 4?). PMID:23258058

Radosevich, Andrew J; Yi, Ji; Rogers, Jeremy D; Backman, Vadim

2012-12-15

341

Water Velocity Measurement on an Extended-Length Submerged Bar Screen at John Day Dam  

SciTech Connect

This report describes a study of water velocity around an extended-length submerged bar screen (ESBS) at John Day Dam. The study was conducted for the U.S. Army Corps of Engineers by AScI Corporation and MEVATEC Corporation in March of 2000. This report was prepared by Pacific Northwest National Laboratory. ESBS are being studied as one method for diverting juvenile migrating fish from the dam's turbine intakes into the gate well and through the juvenile fish bypass channels.

Weiland, Mark A.; Escher, Charles

2001-04-02

342

BUNCH-LENGTH MEASUREMENTS AT SCSS TEST ACCELERATOR TOWARD XFEL\\/SPRING8  

Microsoft Academic Search

The SCSS test accelerator, which was constructed to check the feasibility of XFEL\\/SPring-8, is being operated for user experiments using stable EUV (Extreme Ultra- violet) SASE. This accelerator provides a high-quality electron beam with parameters, such as a bunch length of 300 fs and a peak current of 700 A, for power saturation of the EUV SASE. Evaluating the parameters

Y. Otake; S. Matsubara; H. Maesaka; K. Tamasaku; T. Togashi; K. Togawa; H. Tanaka; Sayo-cho Kouto; Hamamatsu Photonics

343

Estimate of the energy spread in a booster cycle via the bunch length measurement  

SciTech Connect

It is important for us to obtain the information of energy spread vs. time in a Booster cycle via the same beam event, for the purpose of minimizing the error caused by the cycle-to-cycle fluctuation. The bunch length (BL) can be extracted from the resistive wall signal (RWS) at different times of a Booster cycle, and from which the energy spread can be estimated.

Yang, Xi; /Fermilab

2004-11-01

344

Intensity and angular correlation measurements of /sup 103/Ru  

SciTech Connect

The level scheme of /sup 103/Rh was investigated using a HPGe detector and a Ge(Li)-NaI(Tl) coincidence spectrometer. Four new transitions were observed, confirmed, and fitted into a proposed level scheme. The ..beta../sup -/ branching ratios and the log ft values were obtained. A measurement of the 513.98--53.3-keV ..gamma gamma.. angular correlation using a HPGe-NaI(Tl) fast coincidence spectrometer yielded the spin assignment 7/2 for the 607.2-keV level and a multipole mixing ratio E1+9.83%M2 for the 513.98-keV ..gamma.. transition.

Darwish, S.M.; Abdel-Malak, S.; Abou-Leila, M.A.; Walley-Eldin, N.; Hassan, A.M.

1987-01-01

345

Frequency of Nonallelic Homologous Recombination Is Correlated with Length of Homology: Evidence that Ectopic Synapsis Precedes Ectopic Crossing-Over  

PubMed Central

Genomic disorders constitute a class of diseases that are associated with DNA rearrangements resulting from region-specific genome instability, that is, genome architecture incites genome instability. Nonallelic homologous recombination (NAHR) or crossing-over in meiosis between sequences that are not in allelic positions (i.e., paralogous sequences) can result in recurrent deletions or duplications causing genomic disorders. Previous studies of NAHR have focused on description of the phenomenon, but it remains unclear how NAHR occurs during meiosis and what factors determine its frequency. Here we assembled two patient cohorts with reciprocal genomic disorders; deletion associated Smith-Magenis syndrome and duplication associated Potocki-Lupski syndrome. By assessing the full spectrum of rearrangement types from the two cohorts, we find that complex rearrangements (those with more than one breakpoint) are more prevalent in copy-number gains (17.7%) than in copy-number losses (2.3%); an observation that supports a role for replicative mechanisms in complex rearrangement formation. Interestingly, for NAHR-mediated recurrent rearrangements, we show that crossover frequency is positively associated with the flanking low-copy repeat (LCR) length and inversely influenced by the inter-LCR distance. To explain this, we propose that the probability of ectopic chromosome synapsis increases with increased LCR length, and that ectopic synapsis is a necessary precursor to ectopic crossing-over.

Liu, Pengfei; Lacaria, Melanie; Zhang, Feng; Withers, Marjorie; Hastings, P.J.; Lupski, James R.

2011-01-01

346

Enhancement of elastic and inelastic scattering lengths in quasi-free-standing graphene measured with contactless microwave spectroscopy  

NASA Astrophysics Data System (ADS)

In this paper, contactless microwave spectroscopy measurements of weak localization in as-grown and hydrogen intercalated quasi-free-standing graphene (QFSG) grown on SiC are presented. Delamination from the substrate is observed by the change from substrate dominated to grain boundaries dominated intervalley elastic scattering in QFSG comparing to epitaxial graphene. In the case of as-grown graphene, the finite coherence length at 0 K caused by an additional inelastic scattering is observed. This additional scattering mechanism vanishes for hydrogen intercalated QFSG, and the significant enhancement of coherence length comparing to as-grown QFSG and epitaxial graphene is observed. The coherence length is comparable to that observed in free-standing graphene. The conditions under which the quantum corrections produce weak localization or weak antilocalization behavior in conductivity are also discussed.

Drabi?ska, Aneta; Kami?ska, Maria; Wo?o?, Agnieszka; Strupinski, W?odek; Wysmo?ek, Andrzej; Bardyszewski, Witold; Bo?ek, Rafa?; Baranowski, J. M.

2013-10-01

347

Reproducibility of coronary optical coherence tomography for lumen and length measurements in humans (The CLI-VAR [Centro per la Lotta contro l'Infarto-VARiability] study).  

PubMed

Frequency-domain optical coherence tomography (FD-OCT) is becoming a useful diagnostic tool for coronary imaging for quantitative coronary analysis. Second-generation FD-OCT produces detailed coronary lumen images. However, the reproducibility of coronary measurements using FD-OCT in humans has not been thoroughly explored. Our goal was to determine the intraobserver, interobserver, and interpullback reproducibility of the in vivo FD-OCT measurements of the lumen area and/or lesion length. Twenty-five patients undergoing coronary angioplasty were included. In all subjects, FD-OCT pullbacks (20 mm/s) were acquired twice from the same coronary segment different from the target lesion, at an interval of 5 minutes, with no other intervention. A total of 9,396 cross-sectional lumen area frames and the relative coronary lesion length of each pullback were analyzed off-line with dedicated software by 2 independent expert readers (A and B). We compared the lumen area and length measurements as follows: pullback 1, read by reader A twice at an interval of 7 days (intraobserver analysis); pullback 1, independently read by readers A and B (interobserver comparison); and pullback 1 versus pullback 2, read by reader A (interpullback comparison). The per-segment and per-frame analyses showed very high and significant correlation coefficients for the interobserver, intraobserver, and interpullback comparisons for the lumen area and lesion length (R ?0.95 and p <0.001 in all cases). Accordingly, the Bland-Altman estimates of bias showed nonsignificant differences in the interobserver, intraobserver, and interpullback comparisons at all levels, with average biases never >0.150 mm(2) for the lumen area or 0.200 mm for the lesion length. In conclusion, coronary imaging using FD-OCT showed excellent reproducibility, with low intraobserver, interobserver, and interpullback variability for both lumen area and lesion length measurements in humans. Thus, FD-OCT can be proposed for precise analysis in the catheterization laboratory to guide decision making and in clinical trials focusing on imaging end points. PMID:22748353

Fedele, Silvio; Biondi-Zoccai, Giuseppe; Kwiatkowski, Piotr; Di Vito, Luca; Occhipinti, Michele; Cremonesi, Alberto; Albertucci, Mario; Materia, Laura; Paoletti, Giulia; Prati, Francesco

2012-06-28

348

Oxygen measurement by multimode diode lasers employing gas correlation spectroscopy.  

PubMed

Multimode diode laser (MDL)-based correlation spectroscopy (COSPEC) was used to measure oxygen in ambient air, thereby employing a diode laser (DL) having an emission spectrum that overlaps the oxygen absorption lines of the A band. A sensitivity of 700 ppm m was achieved with good accuracy (2%) and linearity (R(2)=0.999). For comparison, measurements of ambient oxygen were also performed by tunable DL absorption spectroscopy (TDLAS) technique employing a vertical cavity surface emitting laser. We demonstrate that, despite slightly degraded sensitivity, the MDL-based COSPEC-based oxygen sensor has the advantages of high stability, low cost, ease-of-use, and relaxed requirements in component selection and instrument buildup compared with the TDLAS-based instrument. PMID:19209216

Lou, Xiutao; Somesfalean, Gabriel; Chen, Bin; Zhang, Zhiguo

2009-02-10

349

Image correlation spectroscopy for measurements of particle densities and colocalization.  

PubMed

Cells interact with their environment through receptor proteins expressed at their plasma membrane, and protein-protein interactions govern the transduction of signals across the membrane into the cell. Therefore, the ability to measure receptor densities and protein colocalization within the membrane of intact cells is of paramount importance. This unit describes a technique to extract these parameters from fluorescence microscopy images obtained using a commercial confocal laser scanning microscope (CLSM) and other similar types of microscopes. It is based on the analysis of spatial fluorescence intensity fluctuations in the images, which can then be related to particle density and aggregation state via calculation of a spatial autocorrelation function, or used to measure particle colocalization via calculation of a spatial cross-correlation function from dual-color images of proteins tagged with two different fluorophores and imaged in two detection channels. These parameters offer key insights on the interaction of the cell with its environment. PMID:23728747

Rappaz, Benjamin; Wiseman, Paul W

2013-06-01

350

The Effect of Error Correlation on Interfactor Correlation in Psychometric Measurement  

ERIC Educational Resources Information Center

This article shows how interfactor correlation is affected by error correlations. Theoretical and practical justifications for error correlations are given, and a new equivalence class of models is presented to explain the relationship between interfactor correlation and error correlations. The class allows simple, parsimonious modeling of error…

Westfall, Peter H.; Henning, Kevin S. S.; Howell, Roy D.

2012-01-01

351

Measurement of laminar burning speeds and Markstein lengths using a novel methodology  

SciTech Connect

Three different methodologies used for the extraction of laminar information are compared and discussed. Starting from an asymptotic analysis assuming a linear relation between the propagation speed and the stretch acting on the flame front, temporal radius evolutions of spherically expanding laminar flames are postprocessed to obtain laminar burning velocities and Markstein lengths. The first methodology fits the temporal radius evolution with a polynomial function, while the new methodology proposed uses the exact solution of the linear relation linking the flame speed and the stretch as a fit. The last methodology consists in an analytical resolution of the problem. To test the different methodologies, experiments were carried out in a stainless steel combustion chamber with methane/air mixtures at atmospheric pressure and ambient temperature. The equivalence ratio was varied from 0.55 to 1.3. The classical shadowgraph technique was used to detect the reaction zone. The new methodology has proven to be the most robust and provides the most accurate results, while the polynomial methodology induces some errors due to the differentiation process. As original radii are used in the analytical methodology, it is more affected by the experimental radius determination. Finally, laminar burning velocity and Markstein length values determined with the new methodology are compared with results reported in the literature. (author)

Tahtouh, Toni; Halter, Fabien; Mounaim-Rousselle, Christine [Institut PRISME, Universite d'Orleans, 8 rue Leonard de Vinci-45072, Orleans Cedex 2 (France)

2009-09-15

352

LIGHT SOURCE: RF deflecting cavity for bunch length measurement in Tsinghua Thomson scattering X-ray source  

NASA Astrophysics Data System (ADS)

An RF deflecting cavity used for bunch length measurement has been designed and fabricated at Tsinghua University for the Thomson Scattering X-Ray Source. The cavity is a 2856 MHz, ?-mode, 3-cell standing-wave cavity, to diagnose the 3.5 MeV beam produced by photocathode electron gun. With a larger power source, the same cavity will again be used to measure the accelerated beam with energy of 50 MeV before colliding with the laser pulse. The RF design using MAFIA for both the cavity shape and the power coupler is reviewed, followed by presenting the fabrication procedure and bench measurement results of two cavities.

Shi, Jia-Ru; Chen, Huai-Bi; Tang, Chuan-Xiang; Huang, Wen-Hui; Du, Ying-Chao; Zheng, Shu-Xin; Ren, Li

2009-06-01

353

Real-time pulse length measurement of few-cycle laser pulses using above-threshold ionization.  

PubMed

The pulse lengths of intense few-cycle (4-10 fs) laser pulses at 790 nm are determined in real-time using a stereographic above-threshold ionization (ATI) measurement of Xe, i.e. the same apparatus recently shown to provide a precise, real-time, every-single-shot, carrier-envelope phase measurement of ultrashort laser pulses. The pulse length is calibrated using spectral-phase interferometry for direct electric-field reconstruction (SPIDER) and roughly agrees with calculations done using quantitative rescattering theory (QRS). This stereo-ATI technique provides the information necessary to characterize the waveform of every pulse in a kHz pulse train, within the Gaussian pulse approximation, and relies upon no theoretical assumptions. Moreover, the real-time display is a highly effective tool for tuning and monitoring ultrashort pulse characteristics. PMID:21369278

Sayler, A M; Rathje, Tim; Müller, W; Kürbis, Ch; Rühle, Klaus; Stibenz, Gero; Paulus, G G

2011-02-28

354

On the reliability of attenuation measurements from ambient noise cross-correlations  

NASA Astrophysics Data System (ADS)

We compare spatially averaged Rayleigh wave attenuation between 10 and 18 sec period observed on the symmetric component of ambient noise cross-correlations with regional seismic event measurements observed by the USArray Transportable Array across the western US. The ambient noise attenuation measurements are shown to be consistent with attenuation observed following an earthquake in Nevada and a mining blast in Wyoming. We demonstrate that common ambient noise data processing procedures such as temporal normalization and spectral whitening can be retained as long as the amplitudes of the cross-correlations are corrected for (1) the duration of the ambient noise cross-correlation, (2) geometrical spreading, and (3) the azimuthal variation in the strength of ambient noise sources. Correction for time-series length can be achieved accurately by dividing the empirical Green's function by the squared root-mean-squared (rms) amplitude of the trailing noise. These results provide strong justification for the ability to constrain seismic attenuation using ambient noise. However, further study of the expected asymmetry in attenuation for waves approaching (incoming) or receding from (outgoing) a central station is needed to understand the effect of uneven noise source distribution prior to estimation of local variations in attenuation.

Lin, Fan-Chi; Ritzwoller, Michael H.; Shen, Weisen

2011-06-01

355

Complex Correlation Measure: a novel descriptor for Poincar? plot  

PubMed Central

Background Poincaré plot is one of the important techniques used for visually representing the heart rate variability. It is valuable due to its ability to display nonlinear aspects of the data sequence. However, the problem lies in capturing temporal information of the plot quantitatively. The standard descriptors used in quantifying the Poincaré plot (SD1, SD2) measure the gross variability of the time series data. Determination of advanced methods for capturing temporal properties pose a significant challenge. In this paper, we propose a novel descriptor "Complex Correlation Measure (CCM)" to quantify the temporal aspect of the Poincaré plot. In contrast to SD1 and SD2, the CCM incorporates point-to-point variation of the signal. Methods First, we have derived expressions for CCM. Then the sensitivity of descriptors has been shown by measuring all descriptors before and after surrogation of the signal. For each case study, lag-1 Poincaré plots were constructed for three groups of subjects (Arrhythmia, Congestive Heart Failure (CHF) and those with Normal Sinus Rhythm (NSR)), and the new measure CCM was computed along with SD1 and SD2. ANOVA analysis distribution was used to define the level of significance of mean and variance of SD1, SD2 and CCM for different groups of subjects. Results CCM is defined based on the autocorrelation at different lags of the time series, hence giving an in depth measurement of the correlation structure of the Poincaré plot. A surrogate analysis was performed, and the sensitivity of the proposed descriptor was found to be higher as compared to the standard descriptors. Two case studies were conducted for recognizing arrhythmia and congestive heart failure (CHF) subjects from those with NSR, using the Physionet database and demonstrated the usefulness of the proposed descriptors in biomedical applications. CCM was found to be a more significant (p = 6.28E-18) parameter than SD1 and SD2 in discriminating arrhythmia from NSR subjects. In case of assessing CHF subjects also against NSR, CCM was again found to be the most significant (p = 9.07E-14). Conclusion Hence, CCM can be used as an additional Poincaré plot descriptor to detect pathology.

Karmakar, Chandan K; Khandoker, Ahsan H; Gubbi, Jayavardhana; Palaniswami, Marimuthu

2009-01-01

356

Accuracy of AFM measurements of the contour length of DNA fragments adsorbed on mica in air and in aqueous buffer  

Microsoft Academic Search

The measurement by atomic force microscope of the contour length of DNA fragments adsorbed on mica has been made as accurate as possible by revisiting the different steps of image acquisition and processing. In air, the DNA helical rise was estimated at 2.97±0.15Å per base pair (bp) (mean±standard deviation) by imaging a 648-bp DNA fragment and 2.95±0.14Å per bp for

Albert Sanchez-Sevilla; Jean Thimonier; Monique Marilley; José Rocca-Serra; Jacques Barbet

2002-01-01

357

Spam Source Clustering by Constructing Spammer Network with Correlation Measure  

NASA Astrophysics Data System (ADS)

Spam filtering is one of the most challenging problems in electric message systems. In general, recent studies on specifying real spam source are based on content filtering because spammers usually falsify their origin. We propose a method to specify spam source based on structural analysis with complex network. We assume that each spam sources either has the same victim list or uses the same spam-hosting program. We treat spam source - target relationship as a bipartite network and construct weighted spam source network by network projection using correlation measure. We find that community clustering methods are inappropriate with spammer network. We group spammers with gradient-based grouping, which uses correlations between nodes as gradient between nodes. We convert them into local minima, which helps to cluster spammers into a few spam source groups. We investigate the weblog spam data with the proposed method and validate it. The method that we propose can be applied to diverse categorization problems, such as multiple text categorization and network subunit clustering.

Shin, Jeongkyu; Kim, Seunghwan

358

Impulsive noise of printers: measurement metrics and their subjective correlation  

NASA Astrophysics Data System (ADS)

In the office and home computing environments, printer impulsive noise has become a significant contributor to user perceived quality or lack thereof, and can affect the user's comfort level and ability to concentrate. Understanding and quantifying meaningful metrics for printer impulsivity is becoming an increasingly important goal for printer manufacturers. Several methods exist in international standards for measuring the impulsivity of noise. For information technology equipment (ITE), the method for detection of impulsive noise is provided in ECMA-74 and ISO 7779. However, there is a general acknowledgement that the current standard method of determining impulsivity by simply measuring A-weighted sound pressure level (SPL) with the impulsive time weighting, I, applied is inadequate to characterize impulsive noise and ultimately to predict user satisfaction and acceptance. In recent years, there has been a variety of new measurement methods evaluated for impulsive noise for both environmental and machinery noise. This paper reviews several of the available metrics, applies the metrics to several printer impulsive noise sources, and makes an initial assessment of their correlation to the subjective impressions of users. It is a review and continuation of the work presented at InterNoise 2005 (Baird, Bray, and Otto).

Baird, Terrence; Otto, Norman; Bray, Wade; Stephan, Mike

2005-09-01

359

Outdoor radon concentration measurements: some correlation with major urban pollutants.  

PubMed

Air pollutants concentration in the urban air strongly depends on the properties of the planetary boundary layer (the lower region of the atmosphere), roughly up to 1 km from Earth's surface. Radioactive radon gas has been recognised by various authors as a valuable natural tracer of transport and dispersion within this layer. To achieve a better comprehension of the urban pollution dynamic in the town of Alessandria, situated in the Po Valley in the north-west of Italy, a system for continuous measurement of radon concentration in outdoor air was experimented. This paper presents the first results obtained: the hourly trend of radon concentration in the diurnal course during different seasons and its correlation with the concentration of the major urban pollutants. PMID:19906661

Garbero, V; Dellacasa, G; Bianchi, D; Magnoni, M; Erbetta, L

2009-11-10

360

Total Diesel Exhaust Particulate Length Measurements Using a Modified Household Smoke Alarm Ionization Chamber  

Microsoft Academic Search

To evaluate the effectiveness of various means to combat the negative health effects of ultrafine particles emitted by internal combustion engines, a reliable, low-cost instrument for dynamic measurements of the exhaust emissions of ultrafine particulate matter (PM) is needed. In this study, an ordinary ionization-type building smoke detector was modified to serve as a measuring ionization chamber and utilized for

Michal Vojtisek-Lom

2011-01-01

361

Measurement of the Axial Length of Cataract Eyes by Laser Doppler Interferometry  

Microsoft Academic Search

Results. Laser Doppler interferometry worked very well except in the cases of the highest cataract grades (4% of the eyes of this study were not measurable because of a too-high lens density). Only 3.5% of the other eyes were not measurable because of fixation problems of the patients. The precision of laser Doppler interferometry is not influenced by the cataract

C. K. Hitzenberger; W. Drexler; C. Dolezal; F. Skorpik; M. Juchem; A. F. Fercher; H. D. Gnadf

362

Extracting decay curves of the correlated fluorescence photons measured in fluorescence correlation spectroscopy  

NASA Astrophysics Data System (ADS)

We have developed a new method to extract the decay curves of the correlated fluorescence photons from the data of fluorescence correlation spectroscopy using time-correlated single photon counting. In this method, a two-dimensional correlation map of photon pairs is generated at an absolute delay time with reference to the excitation-emission delay of each photon. Using a dye-labeled DNA as an example, we have demonstrated that the decay curve of the correlated fluorescence photons is separated from the uncorrelated background signals simply by subtracting a two-dimensional correlation map at sufficiently long delay time without additional prior information.

Ishii, Kunihiko; Tahara, Tahei

2012-01-01

363

Actively cooled pump limiters and power scrape-off length measurements in Tore-Supra  

NASA Astrophysics Data System (ADS)

Tore-Supra is a superconducting tokamak aimed at studying long plasma pulses (>30 s). It is equipped with two types of pump limiters (PL). A provisional type, semi-inertially cooled between shots, has been used for plasma scrape-off characterization. The e-folding length ?q for power deposition on these components has been unfolded (1.0

Guilhem, D.; Seigneur, A.; Chappuis, P.; Chatelier, M.; Demichelis, C.; Deschamps, P.; Grosman, A.; Hess, W.; Lecoustey, P.; Loarer, T.; Poutchy, L.; Schlosser, J.

1992-12-01

364

Length scales in alloy dissolution and measurement of absolute interfacial free energy.  

PubMed

De-alloying is the selective dissolution of one or more of the elemental components of an alloy. In binary alloys that exhibit complete solid solubility, de-alloying of the less noble component results in the formation of nanoporous metals, a materials class that has attracted attention for applications such as catalysis, sensing and actuation. In addition, the occurrence of de-alloying in metallic alloy systems under stress is known to result in stress-corrosion cracking, a key failure mechanism in fossil fuel and nuclear plants, ageing aircraft, and also an important concern in the design of nuclear-waste storage containers. Central to the design of corrosion-resistant alloys is the identification of a composition-dependent electrochemical critical potential, Vcrit, above which the current rises dramatically with potential, signalling the onset of bulk de-alloying. Below Vcrit, the surface is passivated by the accumulation of up to several monolayers of the more noble component. The current understanding of the processes that control Vcrit is incomplete. Here, we report on de-alloying results of Ag/Au superlattices that clarify the role of pre-existing length scales in alloy dissolution. Our data motivated us to re-analyse existing data on critical potentials of Ag-Au alloys and develop a simple unifying picture that accounts for the compositional dependence of solid-solution alloy critical potentials. PMID:17099702

Rugolo, J; Erlebacher, J; Sieradzki, K

2006-11-12

365

Evidence of Enlarged Drift Length in Nanocrystalline Porous Silicon Layers by Time-of-Flight Measurements  

Microsoft Academic Search

The electron transport mechanism of nanocrystalline porous silicon (PS) has been studied for a self-supporting PS layer by a time-of-flight (TOF) measurement. The observed TOF transient photocurrent curves are different from those of both single crystalline silicon (c-Si) and amorphous silicon (a-Si). On the basis of the mobility-lifetime product (mutau) deduced from TOF measurements, it is shown that the electron

Akira Kojima; Nobuyoshi Koshida

2001-01-01

366

Noninvasive Doppler-derived myocardial performance index: Correlation with simultaneous measurements of cardiac catheterization measurements  

Microsoft Academic Search

A simple, reproducible, noninvasive Doppler index for the assessment of overall cardiac function has been described previously. The purpose of this study was to correlate the Doppler index with accepted indexes of cardiac catheterization of left ventricular performance. Thirty-four patients with ischemic heart disease or idiopathic dilated cardiomyopathy prospectively underwent a simultaneous cardiac catheterization and Doppler echocardiographic study. Invasive measurements

Chuwa Tei; Rick A. Nishimura; James B. Seward; A. Jamil Tajik

1997-01-01

367

Measurement of diffusion in articular cartilage using fluorescence correlation spectroscopy  

PubMed Central

Background Fluorescence correlation spectroscopy (FCS) provides information about translational diffusion of fluorescent molecules in tiny detection volumes at the single-molecule level. In normal states, cartilage tissue lacks vascularity, so chondrocyte metabolism depends on diffusion for molecular exchanges. The abundant extracellular matrix (ECM) of cartilage is maintained by a limited number of chondrocytes. ECM plays an important role in the regulation of chondrocyte functions. In this study, FCS was used to measure diffusion behaviors of albumin, the major protein of the intra-articular space, using normal and degenerated cartilage. Preliminary investigation of fluorescence dyes including Alexa 488, Rhodamine 6G and Rhodamine 123 was conducted to evaluate their properties in cartilage. Results The results indicate that the diffusion behaviors of fluorescently lableded albumin can be observed using FCS in both normal and chemically degenerated cartilage. Conclusions This work demonstrates the capability of FCS for direct measurement of diffusion in cartilaginous ECM. When the diffusion characteristics of fluorescent probes in ECM are clarified using FCS evaluation, FCS will be applicable as a method for early diagnosis of osteoarthritis, which is accompanied by increased abnormalities of ECM and also as tool for evaluating bio-engineered artificial cartilage for autologous chondrocyte implantation.

2011-01-01

368

Critical current versus strain measurement up to 21 T and 1000 A of long length superconducting wires and tapes  

NASA Astrophysics Data System (ADS)

A device has been developed to measure the critical current of long length superconductors under uniaxial strain up to 1000 A and up to 21 T. The latter is based on a modified Walters spring (WASP) where zero applied strain can be precisely controlled. The length of the investigated conductor is on the order of 1 m with a typical gauge length between the voltage taps of about 0.5 m. This facilitates the measurement of critical currents at an electric field criterion as low as 0.01 ?V/cm, which is particularly important for superconductors to be used in magnets which are operated in the persistent mode. The operation of the WASP was simulated by finite element calculations indicating that the radial stress (contact pressure) of the superconductor is less than 5% of the axial stress. The performance of the probe is demonstrated for several Nb3Sn conductors with round and rectangular cross section, respectively, as well as for a Bi-2223 tape.

Seeber, B.; Uglietti, D.; Abächerli, V.; Bovier, P.-A.; Eckert, D.; Kübler, G.; Lezza, P.; Pollini, A.; Flükiger, R.

2005-09-01

369

Influence of the chain length on the dynamic viscosity at high pressure of some 2-alkylamines: Measurements and comparative study of some models  

NASA Astrophysics Data System (ADS)

This work reports the dynamic viscosity data (a total of 93 points) of 2-alkylamines, which exhibit small association, consisting of 2-aminobutane, 2-aminopentane, 2-aminoheptane and 2-aminooctane at four temperatures between 293.15 K and 353.15 K (every 20 K), and pressures up to 100 MPa (every 20 MPa) which allows to study the influence of the chain length. A falling-body viscometer with an uncertainty of ±2% was used to perform these measurements. The variations of dynamic viscosity are discussed with respect to their behaviour due to chain length. Seven different models, most of them with a physical and theoretical background, are studied in order to investigate how they take the chain length effect into account through their required model parameters. The evaluated models are based on the empirical Vogel-Fulcher-Tamman (VFT) representation (combined with a Tait-like equation), the rough hard-sphere scheme, the concept of the free-volume, the friction theory, a correlation derived from molecular dynamics, a model based on Eyring's absolute rate theory combined with cubic EoS. A scaling viscosity representation has also been considered. These models need some adjustable parameters except the molecular dynamics correlation that is entirely predictive. Overall a satisfactory representation of the viscosity of these 2-alkylamines is found for the different models within the considered T, p range taking into account their simplicity. Moreover, it has been verified that the viscosity is a unique function of TV ? where the exponent ? is generally related to the steepness of the intermolecular repulsive potential ( T: temperature and V: specific volume).

Yoshimura, Masatoshi; Boned, Christian; Galliéro, Guillaume; Bazile, Jean-Patrick; Baylaucq, Antoine; Ushiki, Hideharu

2010-04-01

370

Unification of quantum and classical correlations and quantumness measures  

NASA Astrophysics Data System (ADS)

We give a pedagogical introduction to quantum discord and discuss the problem of separation of total correlations in a given quantum state into entanglement, dissonance, and classical correlations using the concept of relative entropy. This allows us to put all correlations on an equal footing. Entanglement and dissonance jointly belong to what is known as quantum discord. Our methods are completely applicable for multipartite systems of arbitrary dimensions. We finally show, using relative entropy, how different notions of quantum correlations are related to each other. This gives a single theory that incorporates all correlations, quantum and classical, and different methods of quantifying them.

Modi, Kavan; Vedral, Vlatko

2011-09-01

371

Evaluation of Length-of-Stain Gas Indicator Tubes for Measuring Carbon Monoxide in Air.  

ERIC Educational Resources Information Center

|Techniques for detection and measurement of carbon monoxide (CO) in air are of interest and utility in many aspects of automotive safety. CO concentrations may range from less than 100 parts per million (ppm), or 0.01 percent, to about 10 percent by volume. Gas indicator tubes have been used for many years primarily as detectors of hazardous…

Klaubert, Earl C.; And Others

372

Measuring displacement fields by cross-correlation and a differential technique: experimental validation  

NASA Astrophysics Data System (ADS)

A digital image correlation (DIC) algorithm for displacement measurements combining cross-correlation and a differential technique was validated through a set of experimental tests. These tests consisted of in-plane rigid-body translation and rotation tests, a tensile mechanical test, and a mode I fracture test. The fracture mechanical test, in particular, was intended to assess the accuracy of the method when dealing with discontinuous displacement fields, for which subset-based image correlation methods usually give unreliable results. The proposed algorithm was systematically compared with the Aramis® DIC-2D commercial code by processing the same set of images. When processing images from rigid-body and tensile tests (associated with continuous displacement fields), the two methods provided equivalent results. When processing images from the fracture mechanical test, however, the proposed method obtained a better qualitative description of the discontinuous displacements. Moreover, the proposed method gave a more reliable estimation of both crack length and crack opening displacement of the fractured specimen.©

Xavier, José; Sousa, António M. R.; Morais, José J. L.; Filipe, Vitor M. J.; Vaz, Mario

2012-04-01

373

Normalized movement quality measures for therapeutic robots strongly correlate with clinical motor impairment measures.  

PubMed

In this paper, we analyze the correlations between four clinical measures (Fugl-Meyer upper extremity scale, Motor Activity Log, Action Research Arm Test, and Jebsen-Taylor Hand Function Test) and four robotic measures (smoothness of movement, trajectory error, average number of target hits per minute, and mean tangential speed), used to assess motor recovery. Data were gathered as part of a hybrid robotic and traditional upper extremity rehabilitation program for nine stroke patients. Smoothness of movement and trajectory error, temporally and spatially normalized measures of movement quality defined for point-to-point movements, were found to have significant moderate to strong correlations with all four of the clinical measures. The strong correlations suggest that smoothness of movement and trajectory error may be used to compare outcomes of different rehabilitation protocols and devices effectively, provide improved resolution for tracking patient progress compared to only pre- and post-treatment measurements, enable accurate adaptation of therapy based on patient progress, and deliver immediate and useful feedback to the patient and therapist. PMID:20388607

Celik, Ozkan; O'Malley, Marcia K; Boake, Corwin; Levin, Harvey S; Yozbatiran, Nuray; Reistetter, Timothy A

2010-04-12

374

Accuracy of AFM measurements of the contour length of DNA fragments adsorbed on mica in air and in aqueous buffer.  

PubMed

The measurement by atomic force microscope of the contour length of DNA fragments adsorbed on mica has been made as accurate as possible by revisiting the different steps of image acquisition and processing. In air, the DNA helical rise was estimated at 2.97 +/- 0.15 A per base pair (bp) (mean +/- standard deviation) by imaging a 648-bp DNA fragment and 2.95 +/- 0.14 A per bp for a 115-bp fragment. This confirms earlier observations suggesting that drying DNA fragments on mica in the presence of nickel induces limited conformational changes. At this point the exact nature of these conformational changes remains unknown. Simple hypotheses are the transconformation of stretches of the DNA molecules to the A-form of the double helix or alteration of the helix structure at the points of contact between DNA and mica. By contrast, in aqueous buffer, the measured helical rise was 3.14 +/- 0.15 A per bp for the 648-bp fragment and 3.17 +/- 0.13 A per bp for the 1115-bp fragment. Thus, measured helical rises do not depend on the fragment length and are significantly shorter than the 3.38 A per bp measured by crystallography, but close to the 3.18 A per bp found in NMR studies. These findings are discussed with respect to discrepancies in earlier results published in the literature. PMID:12213016

Sanchez-Sevilla, Albert; Thimonier, Jean; Marilley, Monique; Rocca-Serra, José; Barbet, Jacques

2002-08-01

375

Herriott Cell Interferometer for Density Measurements in Small-Scale Length Plasmas  

NASA Astrophysics Data System (ADS)

The introduction of a Herriott cell into a standard quadrature heterodyne interferometer is evaluated and demonstrated to increase the resolution of the system. Measurements of electron and neutral density during and after the current pulse are sought for modeling purposes for spacecraft contamination from Pulsed Plasma Thrusters. Testing is performed on the UIUC PPT-4, a coaxial electrothermal Pulsed Plasma Thruster pulsing at 20 J. Analytical and experimental analysis is conducted to determine the integrity of the phase front and the effect of multiple passes on the density measurements taken. The phase front quality is found to be acceptable for interferometric purposes and density measurements are taken for 2, 6, 14, and 18 passes in the Herriott cell. The advantage of the cell is obvious at late times when the external room vibrations induce an apparent phase shift in the same direction as neutral particles. Due to the same dependence on wavelength, 2 laser frequencies cannot be used to separate neutral and vibration contributions. The Herriott cell allows a density resolution increase linear with the number of passes that does not increase the vibrational component. Uncertainties from both vibrational sources and shot-to-shot variations of the thruster itself are investigated and characterized for this system. Due to variations in room vibrations on a day to day basis, the cell was unable to characterize the neutral density of the thruster. However, for single tests, neutral density measurements were acquired. The Herriott cell with 18 passes introduced a 9-fold increase in resolution over the standard 2-pass interferometric setup. At 200 microseconds for single tests at 14 and 18 passes (^20 shots averaged) neutral density at the exit plane was shown to be no more than 1*1016/cu cm. Peak electron density (4 microseconds) was shown to be 5.0*1015 +/- 1.1*1015/cu cm.

Antonsen, Erik; Burton, Rodney; Engelman, Scott; Spanjers, Greg

2000-06-01

376

Band structure of 146Ce studied through ?-? angular correlation measurements  

NASA Astrophysics Data System (ADS)

The ?-decay of 146La was studied using the on-line isotope separator KUR-ISOL. Gamma-gamma angular correlation measurements were performed with a 4-Ge detectors system. Spin assignments of three levels were made: 3+ for the 1576.5 keV level, 4+ for the 1627.1 keV level and 5+ for the 1810.2 keV level. The mixing ratios (E2/M1) were deduced to be ?183.2= 0.25 +/- 0.08, ?638.9= 0.33 +/- 0.05, ?959.0= 1.19+0.16-0.14, ?1015.9= 5.4+3.1-1.5 and ?1318.1= 6.5+1.7-1.1. These were compared to the calculated values obtained in three cases involving different Majorana force parameter values. The band structure of 146Ce is discussed based on the results of calculation using the IBM-2 theory.

Yamada, S.; Taniguchi, A.; Okano, K.; Aoki, K.

377

Clinical Measurement of von Willebrand Factor by Fluorescence Correlation Spectroscopy  

PubMed Central

BACKGROUND Identification of von Willebrand factor (vWF) abnormalities in a variety of conditions is hampered by the limitations of currently available diagnostic tests. Although direct multimer visualization by immunoelectrophoresis is a commonly used method, it is impractical as a routine clinical test. In this study, we used a biophysical analysis tool, fluorescence correlation spectroscopy (FCS), to measure vWF distributions. The goals were to develop a method that is quicker and simpler than vWF gel electrophoresis and to evaluate the potential of FCS as a clinical diagnostic technique. METHODS We analyzed plasma from 12 patients with type 1 von Willebrand disease (vWD), 14 patients with type 2 vWD, and 10 healthy controls using a fluctuation-based immunoassay approach. RESULTS FCS enabled identification and proper classification of type 1 and type 2 vWD, producing quantitative results that correspond to qualitative gel multimer patterns. FCS required minimal sample preparation and only a 5-min analysis time. CONCLUSIONS This study represents the first implementation of FCS for clinical diagnostics directly on human plasma. The technique shows potential for further vWF studies and as a generally applicable laboratory test method.

Torres, Richard; Genzen, Jonathan R.; Levene, Michael J.

2013-01-01

378

Inter-ELM power decay length for JET and ASDEX upgrade: measurement and comparison with heuristic drift-based model.  

PubMed

Experimental measurements of the SOL power decay length (?(q)) estimated from analysis of fully attached divertor heat load profiles from two tokamaks, JET and ASDEX Upgrade, are presented. Data was measured by means of infrared thermography. An empirical scaling reveals parametric dependency ?(q) in mm = 0.73B(T)(-0.78)q(cyl)(1.2)P(SOL)(0.1)R(geo)(0), where B(T)(T) describes the toroidal magnetic field, q(cyl) the cylindrical safety factor, P(SOL)(MW) the power crossing the separatrix and R(geo)(m) the major radius of the device. A comparison of these measurements to a heuristic particle drift-based model shows satisfactory agreement in both absolute magnitude and scaling. Extrapolation to ITER gives ?(q) ? 1 mm. PMID:22181888

Eich, T; Sieglin, B; Scarabosio, A; Fundamenski, W; Goldston, R J; Herrmann, A

2011-11-14

379

Correlation measurements in precipitation at linear polarisation using dual-channel radar  

Microsoft Academic Search

Correlation measurements at linear polarisation in dual-channel precipitation radars are investigated. It is shown that the correlation between orthogonal linearly polarised backscatter components provides information on precipitation particle orientation and shape. Thus, as in the case at circular polarisation, correlation measurements can be a useful concept for particle indentification. Preliminary results from measurements made at 9.6 GHz are presented.

Y. M. M. Antar; A. Hendry

1985-01-01

380

Review and analysis of VHF/UHF field strength measurements: Measurements at VHF over path lengths greater than 100 km  

NASA Astrophysics Data System (ADS)

In 1983 CCIRIWP 5/5 put forward a number of proposals for improvements to the field strength prediction methods of CCIR Recommendation 370 and associated Report 239, as used for international planning negotiations in the VHF and UHF Broadcast Bands. Described are the results of studies carried out by the BBC, in conjunction with other propagation investigations, to assess the validity of those proposals of IWP 5/5 which relate to propagation over path lengths in excess of about 100 km in the VHF Bands. It is concluded that these proposals can be supported with only one exception, relating to an addition of 7 dB to beyond-horizon oversea curves. Subsequently, the VHF proposals (excepting the one relating to the 7 dB correction) have been endorsed by CCIR Study Group 5 and adopted by the Plenar Meeting in 1986 for inclusion as modifications to Recommendation 370. Even so, limitations in the exsiting methods are identified and further work is proposed.

Sandell, R. S.; Bell, C. P.; Taplin, D. W.

1986-12-01

381

Path-length-resolved measurements of multiple scattered photons in static and dynamic turbid media using phase-modulated low-coherence interferometry.  

PubMed

In optical Doppler measurements, the path length of the light is unknown. To facilitate quantitative measurements, we develop a phase-modulated Mach-Zehnder interferometer with separate fibers for illumination and detection. With this setup, path-length-resolved dynamic light scattering measurements of multiple scattered light in static and dynamic turbid media are performed. Optical path length distributions spanning a range from 0 to 11 mm are measured from the area under the phase modulation peak around the modulation frequency in the power spectrum. A Doppler-broadened phase modulation interference peak is observed that shows an increase in the average Doppler shift with optical path length, independent of absorption. Validation of the estimated path length distributions is done by measuring their deformation for increasing absorption and comparing these observations with predictions based on Lambert-Beer's law. PMID:17477735

Varghese, Babu; Rajan, Vinayakrishnan; Van Leeuwen, Ton G; Steenbergen, Wiendelt

382

Measurements of large scale-length plasmas produced from gas-filled targets  

SciTech Connect

Apart from their intrinsic interest, plasma physics processes are important because they affect the coupling of the laser energy into laser-irradiated targets. Recently, new gas-filled targets have been developed to create large mm-size plasmas for the study of stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS). We present x-ray images and x-ray spectra to characterize these targets, which show that the plasmas are homogeneous, have electron densities of {approximately}10{sup 21} cm{sup {minus}3}, and attain electron temperatures of {approximately}3 keV. We also present SBS measurements to demonstrate how systematic studies of physical phenomena can be performed using these targets.

Back, C.A.; Berger, R.L.; Estabrook, K. [and others

1995-06-30

383

New sequentially etched quantum-yield technique for measuring surface recombination velocity and diffusion lengths of solar cells  

SciTech Connect

We have developed a new technique to characterize the individual layers of high-efficiency solar cells. In general, the technique allows one to set lower bounds for diffusion lengths and upper and lower bounds for interface recombination velocity. This is sufficient to determine which parameter limits performance, and often the actual parameter values are also determined accurately. We obtain this information by fitting a theoretical model to quantum-yield spectra measured on a sample in its initial state, and after its window passivation and top active layers are sequentially etched away. With such data on two p on n GaAs solar cells with Al/sub x/Ga/sub 1-//sub x/As passivation, we determined minority-carrier hole diffusion lengths of 1.0 +- 0.2 and 0.2 +- 0.05 ..mu.. in the Te-doped n layers for first and second samples, respectively. We found lower limits for the minority-carrier electron diffusion lengths in the top p layers of 2.0 ..mu.. in the carbon-doped first sample and 4.0 ..mu.. in the Mg-doped second sample. We determined interface recombination velocities of 4.0 +- 0.5 (10/sup 5/) cm/s at the carbon-doped p layer's interface with its Al/sub 0.45/Ga/sub 0.55/As passivation layer, and between 500 and 10/sup 4/ cm/s for the Mg-doped layer's interface with its Al/sub 0.9/Ga/sub 0.1/As passivation layer. After stripping the Al/sub x/Ga/sub 1-//sub x/As layer away, we measured surface recombination velocities of 8.0 +- 2.0 (10/sup 6/) cm/s on the carbon-doped sample, and 1.0 +- 0.2 (10/sup 7/) cm/s on the Mg-doped sample.

Partain, L.D.; Kuryla, M.S.; Fraas, L.M.; McLeod, P.S.; Cape, J.A.

1987-06-01

384

Effectively classically correlated state of a measured system and a bosonic measurement apparatus  

SciTech Connect

We consider a multilevel system coupled to a bosonic measurement apparatus. We derive exact expressions for the time-dependent expectation values of a large class of physically relevant observables that depend on degrees of freedom of both systems. We find that, for this class, though the two systems become entangled as a result of their interaction, they appear classically correlated for long enough times. The unique corresponding time-dependent separable state is determined explicitly. To better understand the physical parameters that control the time scale of this effective disentanglement process, we study a one-dimensional measurement apparatus.

Camalet, S. [Laboratoire de Physique Theorique de la Matiere Condensee, UMR 7600, Universite Pierre et Marie Curie, 4, place Jussieu, F-75005 Paris (France)

2011-04-15

385

Comparison of SANS and DLS hydrodynamic correlation lengths for a polystyrene/methyl-cyclohexane solution in the vicinity of temperature- or pressure-induced critical demixing  

NASA Astrophysics Data System (ADS)

Phase diagrams for polystyrene(PS)/deuteromethylcyclohexane have been determined over a wide range of temperature and pressure. In this work, we report hydrodynamic and SANS correlation lengths, ?DLS and ?SANS, and intensities, IDLS and ISANS, from dynamic light and small-angle neutron scattering, respectively, along various approaches to a near-critical demixing surface, f (T*, P*)cr. We examined isobaric, isothermal, and more complicated paths, sometimes in the hypercritical region. (At a lower hypercritical temperature ?(f (T*, P*)/?P=0 and ?2(f (T*, P*)/?P2>0, and at a lower hypercritical pressure ?(f (T*, P*)cr/?T=0 and ?2(f (T*, P*)cr/?T2>0.) Both ?DLS and ?SANS diverge as (T*, P*) is approached, but the strength of the divergence depends on the direction of approach to (P*, T*)cr. We discuss a modified scaling expression which describes the observations.

Szydlowski, J.; Rebelo, L. P.; Wilczura, H.; Dadmun, M.; Melnichenko, Y.; Wignall, G. D.; van Hook, W. A.

1998-04-01

386

An Evolutionarily Conserved Family of Virion Tail Needles Related to Bacteriophage P22 gp26: Correlation between Structural Stability and Length of the -Helical Trimeric Coiled Coil  

SciTech Connect

Bacteriophages of the Podoviridae family use short noncontractile tails to inject their genetic material into Gram-negative bacteria. In phage P22, the tail contains a thin needle, encoded by the phage gene 26, which is essential both for stabilization and for ejection of the packaged viral genome. Bioinformatic analysis of the N-terminal domain of gp26 (residues 1-60) led us to identify a family of genes encoding putative homologues of the tail needle gp26. To validate this idea experimentally and to explore their diversity, we cloned the gp26-like gene from phages HK620, Sf6 and HS1, and characterized these gene products in solution. All gp26-like factors contain an elongated {alpha}-helical coiled-coil core consisting of repeating, adjacent trimerization heptads and form trimeric fibers with length ranging between about 240 to 300 {angstrom}. gp26 tail needles display a high level of structural stability in solution, with Tm (temperature of melting) between 85 and 95 C. To determine how the structural stability of these phage fibers correlates with the length of the {alpha}-helical core, we investigated the effect of insertions and deletions in the helical core. In the P22 tail needle, we identified an 85-residue-long helical domain, termed MiCRU (minimal coiled-coil repeat unit), that can be inserted in-frame inside the gp26 helical core, preserving the straight morphology of the fiber. Likewise, we were able to remove three quarters of the helical core of the HS1 tail needle, minimally decreasing the stability of the fiber. We conclude that in the gp26 family of tail needles, structural stability increases nonlinearly with the length of the {alpha}-helical core. Thus, the overall stability of these bacteriophage fibers is not solely dependent on the number of trimerization repeats in the {alpha}-helical core.

Bhardwaj, A.; Walker-Kopp, N; Casjens, S; Cingolani, G

2009-01-01

387

Doing more with less: a method for low total mass, affinity measurement using variable-length nanotethers.  

PubMed

Interactions between biomolecules are an important feature of biological systems and understanding these interactions is a key goal in biochemical studies. Using conventional techniques, such as surface plasmon resonance and isothermal titration calorimetry, the determination of the binding constants requires a significant amount of time and resources to produce and purify sufficient quantities of biomolecules in order to measure the affinity of biological interactions. Using DNA hybridization, we have demonstrated a new technique based on the use of nanotethers and time-resolved Forster resonance energy transfer (FRET) that significantly reduces the amount of material required to carry out quantitative binding assays. Test biomolecules were colocalized and attached to a surface using DNA tethers constructed from overlapping oligonucleotides. The length of the tethers defines the concentration of the tethered biomolecule. Effective end concentrations ranging from 56 nM to 3.8 ?M were demonstrated. The use of variable length tethers may have wider applications in the quantitative measurement of affinity binding parameters. PMID:22029261

Perrins, Richard D; Orchard, Craig; Zavodszky, Maria; Kasry, Amal; Nikolaev, Nikolay; Harwood, Adrian; Borri, Paola; Dale, Trevor

2011-11-08

388

Influence of FBG sensors length on temperature measures in laser-irradiated pancreas: Theoretical and experimental evaluation.  

PubMed

Temperature distribution T(x,y,z,t) in tissue undergoing Laser-induced Interstitial Thermotherapy (LITT) plays a crucial role on treatment outcome. Theoretical and experimental assessment of temperature on ex vivo laser-irradiated pancreas is presented. The aim of this work is to assess the influence of thermometers dimensions on temperature measures during LITT. T(x,y,z,t) inside tissue is monitored by optical sensors, i.e., Fiber Bragg Gratings (FBGs): three FBGs with lengths of 10 mm and nine FBGs of 1 mm, at different distances (2 mm, 5 mm and 10 mm) and different quotes (0 mm, 2 mm and 4 mm) from the laser fiber tip are used. Theoretical punctual T(x,y,z,t) is averaged out on both 10 mm and 1 mm in order to compare numerical predictions with experimental data. Results demonstrate the influence of FBG length on T(x,y,z,t) measures. This phenomenon depends on the distance between sensor and applicator: it is particularly significant close to the applicator tip (2 mm) because of the high spatial T(x,y,z,t) gradient within the tissue. Both theoretical results and experimental ones show that just at a distance of 10 mm from the tip, differences between T(x,y,z,t) provided by FBGs of 10 mm and 1 mm are negligible. PMID:24110543

Saccomandi, P; Lupi, G; Schena, E; Polimadei, A; Caponero, M; Panzera, F; Martino, M; Di Matteo, F M; Sciuto, S; Silvestri, S

2013-07-01

389

Clinical Correlates to Laboratory Measures for use in Non-Contact Anterior Cruciate Ligament Injury Risk Prediction Algorithm  

PubMed Central

Background Prospective measures of high knee abduction moment during landing identify female athletes at high risk for non-contact anterior cruciate ligament injury. Biomechanical laboratory measurements predict high knee abduction moment landing mechanics with high sensitivity (85%) and specificity (93%). The purpose of this study was to identify correlates to laboratory-based predictors of high knee abduction moment for use in a clinic-based anterior cruciate ligament injury risk prediction algorithm. The hypothesis was that clinically obtainable correlates derived from the highly predictive laboratory-based models would demonstrate high accuracy to determine high knee abduction moment status. Methods Female basketball and soccer players (N=744) were tested for anthropometrics, strength and landing biomechanics. Pearson correlation was used to identify clinically feasible correlates and logistic regression to obtain optimal models for high knee abduction moment prediction. Findings Clinical correlates to laboratory-based measures were identified and predicted high knee abduction moment status with 73% sensitivity and 70% specificity. The clinic-based prediction algorithm, including (Odds Ratio: 95% confidence interval) knee valgus motion (1.43:1.30–1.59 cm), knee flexion range of motion (.98:0.96–1.01 deg), body mass (1.04:1.02–1.06 kg), tibia length (1.38:1.25–1.52 cm) and quadriceps to hamstring ratio (1.70:1.06–2.70) predicted high knee abduction moment status with C statistic 0.81. Interpretation The combined correlates of increased knee valgus motion, knee flexion range of motion, body mass, tibia length and quadriceps to hamstrings ratio predict high knee abduction moment status in female athletes with high sensitivity and specificity.

Myer, Gregory D.; Ford, Kevin R.; Khoury, Jane; Succop, Paul; Hewett, Timothy E.

2010-01-01

390

Measuring spin correlations in optical lattices using superlattice potentials  

NASA Astrophysics Data System (ADS)

We suggest two experimental methods for probing both short- and long-range spin correlations of atoms in optical lattices using superlattice potentials. The first method involves an adiabatic doubling of the periodicity of the underlying lattice to probe neighboring singlet (triplet) correlations for fermions (bosons) by the occupation of the resulting vibrational ground state. The second method utilizes a time-dependent superlattice potential to generate spin-dependent transport by any number of prescribed lattice sites, and probes correlations by the resulting number of doubly occupied sites. For experimentally relevant parameters, we demonstrate how both methods yield large signatures of antiferromagnetic correlations of strongly repulsive fermionic atoms in a single shot of the experiment. Lastly, we show how this method may also be applied to probe d-wave pairing, a possible ground-state candidate for the doped repulsive Hubbard model.

Pedersen, K. G. L.; Andersen, B. M.; Bruun, G. M.; Syljuåsen, O. F.; Sørensen, A. S.

2011-10-01

391

Influence functions of the Spearman and Kendall correlation measures  

Microsoft Academic Search

Nonparametric correlation estimators as the Kendall and Spearman correlation are widely used in the applied sciences. They\\u000a are often said to be robust, in the sense of being resistant to outlying observations. In this paper we formally study their\\u000a robustness by means of their influence functions and gross-error sensitivities. Since robustness of an estimator often comes\\u000a at the price of

Christophe Croux; Catherine Dehon

2010-01-01

392

Digital Correlation Technique for Third Order Intensity Correlation Measurements of Light.  

National Technical Information Service (NTIS)

An electronic correlator is described in which the arrival times of photoelectric pulses are registered directly in digital form. Pairs of interval times, corresponding to three photoelectric pulses, are then mapped onto a one-dimensional array of numbers...

S. Chopra L. Mandel

1972-01-01

393

Extended x-ray absorption fine structure measurement of bond-length strain in epitaxial Gd2O3 on GaAs(001)  

Microsoft Academic Search

Extended X-ray absorption fine structure (EXAFS) has been used to measure the bond length in a 23 A epitaxially grown Gd2O3 film on GaAs(001). The Gd-O bond length is determined to be 2.389 ± 0.013 A, which corresponds to an increase of 2.7% or 0.063 A relative to the bond length in bulk Gd2O3 powder. In the plane of the

Erik Nelson; Joseph Woicik; Minghwei Hong

2000-01-01

394

Theory and Measurement of Partially Correlated Persistent Scatterers  

NASA Astrophysics Data System (ADS)

Interferometric synthetic aperture radar (InSAR) time-series methods can effectively estimate temporal surface changes induced by geophysical phenomena. However, such methods are susceptible to decorrelation due to spatial and temporal baselines (radar pass separation), changes in orbital geometries, atmosphere, and noise. These effects limit the number of interferograms that can be used for differential analysis and obscure the deformation signal. InSAR decorrelation effects may be ameliorated by exploiting pixels that exhibit phase stability across the stack of interferograms. These so-called persistent scatterer (PS) pixels are dominated by a single point-like scatterer that remains phase-stable over the spatial and temporal baseline. By identifying a network of PS pixels for use in phase unwrapping, reliable deformation measurements may be obtained even in areas of low correlation, where traditional InSAR techniques fail to produce useful observations. PS identification is challenging in natural terrain, due to low reflectivity and few corner reflectors. Shanker and Zebker [1] proposed a PS pixel selection technique based on maximum-likelihood estimation of the associated signal-to-clutter ratio (SCR). In this study, we further develop the underlying theory for their technique, starting from statistical backscatter characteristics of PS pixels. We derive closed-form expressions for the spatial, rotational, and temporal decorrelation of PS pixels as a function of baseline and signal-to-clutter ratio. We show that previous decorrelation and critical baseline expressions [2] are limiting cases of our result. We then describe a series of radar scattering simulations and show that the simulated decorrelation matches well with our analytic results. Finally, we use our decorrelation expressions with maximum-likelihood SCR estimation to analyze an area of the Hayward Fault Zone in the San Francisco Bay Area. A series of 38 images of the area were obtained from C-band ERS radar satellite passes between May 1995 and December 2000. We show that the interferogram stack exhibits PS decorrelation trends in agreement with our analytic results. References 1. P. Shanker and H. Zebker, "Persistent scatterer selection using maximum likelihood estimation," Geophysical Research Letters, Vol. 34, L22301, 2007. 2. H. Zebker and J. Villasenor, "Decorrelation in Interferometric Radar Echos," IEEE Transactions on Geoscience and Remote Sensing, Vol. 30, No. 5, Sept. 1992.

Lien, J.; Zebker, H. A.

2011-12-01

395

Measures of galaxy environment - II. Rank-ordered mark correlations  

NASA Astrophysics Data System (ADS)

We analyse environmental correlations using mark clustering statistics with the mock galaxy catalogue constructed by Muldrew et al. (Paper I). We find that mark correlation functions are able to detect even a small dependence of galaxy properties on the environment, quantified by the overdensity 1 + ?, while such a small dependence would be difficult to detect by traditional methods. We then show that rank ordering the marks and using the rank as a weight is a simple way of comparing the correlation signals for different marks. With this we quantify to what extent fixed-aperture overdensities are sensitive to large-scale halo environments, nearest-neighbour overdensities are sensitive to small-scale environments within haloes and colour is a better tracer of overdensity than luminosity.

Skibba, Ramin A.; Sheth, Ravi K.; Croton, Darren J.; Muldrew, Stuart I.; Abbas, Ummi; Pearce, Frazer R.; Shattow, Genevieve M.

2013-02-01

396

Forearm Length – A New Tool to Standardize Bone Parameters of the Forearm Measured with Peripheral Quantitative Computed Tomography in Individuals with Disproportional Growth of Forearm Length and Body Height  

Microsoft Academic Search

Aim: To investigate the relationship of forearm length (FL) or height to bone parameters of the forearm of a normal pediatric population in comparison to individuals with osteogenesis imperfecta (OI). Methods: Data on FL, height and peripheral quantitative computed tomography measurements of the forearm were collected from participants of the DONALD study (140 males and 156 females; age 5–19 years)

Oliver Fricke; Oliver Semler; Ralf Beccard; Christof Land; Roland Ehrlich; Thomas Remer; Eckhard Schoenau

2009-01-01

397

On the use of correlation as a measure of network connectivity.  

PubMed

Numerous studies have demonstrated that brain networks derived from neuroimaging data have nontrivial topological features, such as small-world organization, modular structure and highly connected hubs. In these studies, the extent of connectivity between pairs of brain regions has often been measured using some form of statistical correlation. This article demonstrates that correlation as a measure of connectivity in and of itself gives rise to networks with non-random topological features. In particular, networks in which connectivity is measured using correlation are inherently more clustered than random networks, and as such are more likely to be small-world networks. Partial correlation as a measure of connectivity also gives rise to networks with non-random topological features. Partial correlation networks are inherently less clustered than random networks. Network measures in correlation networks should be benchmarked against null networks that respect the topological structure induced by correlation measurements. Prevalently used random rewiring algorithms do not yield appropriate null networks for some network measures. Null networks are proposed to explicitly normalize for the inherent topological structure found in correlation networks, resulting in more conservative estimates of small-world organization. A number of steps may be needed to normalize each network measure individually and control for distinct features (e.g. degree distribution). The main conclusion of this article is that correlation can and should be used to measure connectivity, however appropriate null networks should be used to benchmark network measures in correlation networks. PMID:22343126

Zalesky, Andrew; Fornito, Alex; Bullmore, Ed

2012-02-11

398

Submicron deformation field measurements: Part 2. Improved digital image correlation  

Microsoft Academic Search

This is the second paper in a series of three devoted to the application of scanning tunneling microscopy (STM) to mechanics problems. In this paper, improvements to the digital image correlation method are outlined, a technique that compares digital images of a specimen surface before and after deformation to deduce its two-dimensional surface displacement field and strains. The necessity of

G. Vendroux; W. G. Knauss

1998-01-01

399

Fertility measures in Polish Black-and-White cattle. 4. Phenotypic and genetic correlations between fertility measures and type traits  

Microsoft Academic Search

Phenotypic and genetic correlations between fertility measures and conformation traits were estimated. Data were records of 38,274 cows; the records consisted of eight fertility traits, five descriptive type traits, height and rump and fourteen linearly scored conformation traits. The correlations were estimated using REML based on linear animal model. The phenotypic correlations between fertility and descriptive type traits were in

W. Jagusiak

400

Scattering noise and measurement artifacts in a single-shot cross-correlator and their suppression  

NASA Astrophysics Data System (ADS)

We studied the optical scattering noise, measurement artifacts, and their suppression in single-shot measurements of prepulse contrast. The measurement noise due to air scattering and the two kinds of measurement artifacts resulting from multiple reflections of the generated correlation signal and correlation between the pulse under test and the internally reflected sampling pulse were experimentally explored. The scattering noise and measurement artifacts significantly degrade the measurement fidelity. We demonstrate the clean measurement of prepulse contrast in a single-shot cross-correlator by attenuating the main peak of the correlation beam with a dot mirror and designing the correlating process based on a periodically-poled lithium niobate crystal embedded in an unpoled wafer. The standard time-scanning measurements of pulse contrast are also performed to confirm the experimental results of our single-shot measurement.

Wang, Yongzhi; Yuan, Peng; Ma, Jingui; Qian, Liejia

2013-05-01

401

Correlation  

NSDL National Science Digital Library

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

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

2009-09-14

402

Estimating age from recapture data: Integrating incremental growth measures with ancillary data to infer age-at-length  

USGS Publications Warehouse

Estimating the age of individuals in wild populations can be of fundamental importance for answering ecological questions, modeling population demographics, and managing exploited or threatened species. Significant effort has been devoted to determining age through the use of growth annuli, secondary physical characteristics related to age, and growth models. Many species, however, either do not exhibit physical characteristics useful for independent age validation or are too rare to justify sacrificing a large number of individuals to establish the relationship between size and age. Length-at-age models are well represented in the fisheries and other wildlife management literature. Many of these models overlook variation in growth rates of individuals and consider growth parameters as population parameters. More recent models have taken advantage of hierarchical structuring of parameters and Bayesian inference methods to allow for variation among individuals as functions of environmental covariates or individual-specific random effects. Here, we describe hierarchical models in which growth curves vary as individual-specific stochastic processes, and we show how these models can be fit using capture-recapture data for animals of unknown age along with data for animals of known age. We combine these independent data sources in a Bayesian analysis, distinguishing natural variation (among and within individuals) from measurement error. We illustrate using data for African dwarf crocodiles, comparing von Bertalanffy and logistic growth models. The analysis provides the means of predicting crocodile age, given a single measurement of head length. The von Bertalanffy was much better supported than the logistic growth model and predicted that dwarf crocodiles grow from 19.4 cm total length at birth to 32.9 cm in the first year and 45.3 cm by the end of their second year. Based on the minimum size of females observed with hatchlings, reproductive maturity was estimated to be at nine years. These size benchmarks are believed to represent thresholds for important demographic parameters; improved estimates of age, therefore, will increase the precision of population projection models. The modeling approach that we present can be applied to other species and offers significant advantages when multiple sources of data are available and traditional aging techniques are not practical. ?? 2011 by the Ecological Society of America.

Eaton, M. J.; Link, W. A.

2011-01-01

403

Cynicism about Organizational ChangeMeasurement, Antecedents, and Correlates  

Microsoft Academic Search

A new construct called Cynicism About Organizational Change (CAOC) was proposed and distinguished from related concepts. The measure of CAOC was supported by confirmatory factor analysis and has acceptable internal consistency reliability. Potential antecedents (measured 21 months before the measurement of CAOC) were examined. Little support was found for CAOC having dispositional roots in one’s general negative affectivity. More support

John P. Wanous; Arnon E. Reichers; James T. Austin

2000-01-01

404

Correlations of properties and structures at different length scales of hydro- and organo-gels based on N-alkyl-(R)-12-hydroxyoctadecylammonium chlorides.  

PubMed

The self-assembly and gelating ability of a set of N-alkyl-(R)-12-hydroxyoctadecylammonium chlorides (NCl-n, where n = 0-6, 18 is the length of the alkyl chain on nitrogen) are described. Several are found to be ambidextrous (gelating both water and a variety of organic liquids) and very efficient (needing less than ca. 0.5 wt % at room temperature). Structure-property correlations at different distance scales of the NCl-n in their hydro- and organo-gels and neat, solid states have been made using X-ray diffraction, neutron scattering, thermal, optical, cryo-SEM and rheological techniques. The self-assembled fibrillar networks consist of spherulitic objects with fibers whose diameters and degrees of twisting differ in the hydro- and organo-gels. Increasing n (and, thus, the molecular length) increases the width of the fibers in their hydrogels; an irregular, less pronounced trend between n and fiber width is observed in the corresponding toluene gels. Time-dependent, small angle neutron scattering data for the isothermal sol-to-gel transformation of sols of NCl-18/toluene to their gels, treated according to Avrami theory, indicate heterogeneous nucleation involving rodlike growth. Rheological studies of gels of NCl-3 in water and toluene confirm their viscoelastic nature and show that the hydrogel is mechanically stronger than the toluene gel. Models for the different molecular packing arrangements within the fibrillar gel networks of the hydro- and organogels have been inferred from X-ray diffraction. The variations in the fibrillar networks provide a comprehensive picture and detailed insights into why seemingly very similar NCl-n behave very differently during their self-assembly processes in water and organic liquids. It is shown that the NCl-n provide a versatile platform for interrogating fundamental questions regarding the links between molecular structure and one-dimensional self-aggregation, leading to gelation. PMID:21978216

Mallia, V Ajay; Terech, Pierre; Weiss, Richard G

2011-10-06

405

A new correlation method for high sensitivity current noise measurements.  

PubMed

The properties of a differential transconductance amplifier coupled with a four channel measurement system are exploited in order to reach a very high sensitivity in current noise measurements. In particular, it is demonstrated that, in proper conditions, the noise contributions coming from the active and passive devices that make up the transresistance amplifier can be virtually eliminated. Moreover, the proposed measurement method allows the evaluation of the impedance of the device under test from noise measurement data. Actual measurement results are also reported that demonstrate the effectiveness of the proposed approach. PMID:18052495

Ciofi, Carmine; Scandurra, Graziella; Merlino, Rosario; Cannatà, Gianluca; Giusi, Gino

2007-11-01

406

Optical Design of a Broadband Infrared Spectrometer for Bunch Length Measurement at the Linac Coherent Light Source  

SciTech Connect

The electron pulses generated by the Linac Coherent Light Source at the SLAC National Accelerator Laboratory occur on the order of tens of femtoseconds and cannot be directly measured by conventional means. The length of the pulses can instead be reconstructed by measuring the spectrum of optical transition radiation emitted by the electrons as they move toward a conducting foil. Because the emitted radiation occurs in the mid-infrared from 0.6 to 30 microns a novel optical layout is required. Using a helium-neon laser with wavelength 633 nm, a series of gold-coated off-axis parabolic mirrors were positioned to direct a beam through a zinc selenide prism and to a focus at a CCD camera for imaging. Constructing this layout revealed a number of novel techniques for reducing the aberrations introduced into the system by the off-axis parabolic mirrors. The beam had a recorded radius of less than a millimeter at its final focus on the CCD imager. This preliminary setup serves as a model for the spectrometer that will ultimately measure the LCLS electron pulse duration.

Williams, Kiel; /SLAC

2012-09-07

407

Fast measurement of sarcomere length and cell orientation in langendorff-perfused hearts using remote focusing microscopy.  

PubMed

Rationale: Sarcomere length (SL) is a key indicator of cardiac mechanical function, but current imaging technologies are limited in their ability to unambiguously measure and characterize SL at the cell level in intact, living tissue. Objective: We developed a method for measuring SL and regional cell orientation using remote focusing microscopy, an emerging imaging modality that can capture light from arbitrary oblique planes within a sample. Methods and Results: We present a protocol that unambiguously and quickly determines cell orientation from user-selected areas in a field of view by imaging 2 oblique planes that share a common major axis with the cell. We demonstrate the effectiveness of the technique in establishing single-cell SL in Langendorff-perfused hearts loaded with the membrane dye di-4-ANEPPS. Conclusions: Remote focusing microscopy can measure cell orientation in complex 2-photon data sets without capturing full z stacks. The technique allows rapid assessment of SL in healthy and diseased heart experimental preparations. PMID:23899961

Botcherby, Edward J; Corbett, Alex; Burton, Rebecca A B; Smith, Chris W; Bollensdorff, Christian; Booth, Martin J; Kohl, Peter; Wilson, Tony; Bub, Gil

2013-07-30

408

Accuracy and precision in camera-based fluorescence correlation spectroscopy measurements.  

PubMed

Imaging fluorescence correlation spectroscopy (FCS) performed using array detectors has been successfully used to quantify the number, mobility, and organization of biomolecules in cells and organisms. However, there have not been any systematic studies on the errors in these estimates that are introduced due to instrumental and experimental factors. State-of-the-art array detectors are still restricted in the number of frames that can be recorded per unit time, sensitivity and noise characteristics, and the total number of frames that can be realistically recorded. These limitations place constraints on the time resolution, the signal-to-noise ratio, and the total measurement time, respectively. This work addresses these problems by using a combination of simulations and experiments on lipid bilayers to provide characteristic performance parameters and guidelines that govern accuracy and precision of diffusion coefficient and concentration measurements in camera-based FCS. We then proceed to demonstrate the effects of these parameters on the capability of camera-based FCS to determine membrane heterogeneity via the FCS diffusion laws, showing that there is a lower length scale limit beyond which membrane organization cannot be detected and which can be overcome by choosing suitable experimental parameters. On the basis of these results, we provide guidelines for an efficient experimental design for camera-based FCS to extract information on mobility, concentration, and heterogeneity. PMID:23521662

Sankaran, Jagadish; Bag, Nirmalya; Kraut, Rachel Susan; Wohland, Thorsten

2013-04-04

409

Resolving Dynamics Structure in the Mlt: Correlative Measurements with Tidi and Hrdi  

NASA Astrophysics Data System (ADS)

Undoubtedly, line of sight Doppler measurements of the terrestrial limb have and continue to provide the longest sequence of routine synoptic wind data of the mesosphere and lower thermosphere. To provide the community with basic information about global MLT winds, UARS/HRDI was launched in 1991 and later joined by TIMED/TIDI in 2001. Correlative observations of the MLT with the two instruments began in February 2002 and continued until April 2005 when battery problems aboard UARS forced the final turn-off of HRDI. TIDI continues observing the MLT to the present day with nearly a 100% duty cycle. On short time intervals (a few days), tidal frequencies are difficult to unambiguously identify from orbit by either HRDI or TIDI due to aliasing issues with single satellite observations. Combining measurements from the two platforms provides a significant improvement in understanding two-dimensional frequency wavenumber spectra for short data sets. This paper will describe the progress that has been made in characterizing migrating and non-migrating diurnal tides in the MLT. Short data sets of several days' length are necessary to identify planetary waves, such as the two-day wave, and its effect on MLT dynamics. These waves can transport water vapour exhaust from rocket launches over large distances providing a seed for enhancing noctilucent cloud formation at high latitudes.

Niciejewski, R.; Skinner, W. R.; Marshall, A.; Cooper, M.

2011-12-01

410

Correlation measure to detect time series distances, whence economy globalization  

NASA Astrophysics Data System (ADS)

An instantaneous time series distance is defined through the equal time correlation coefficient. The idea is applied to the Gross Domestic Product (GDP) yearly increments of 21 rich countries between 1950 and 2005 in order to test the process of economic globalisation. Some data discussion is first presented to decide what (EKS, GK, or derived) GDP series should be studied. Distances are then calculated from the correlation coefficient values between pairs of series. The role of time averaging of the distances over finite size windows is discussed. Three network structures are next constructed based on the hierarchy of distances. It is shown that the mean distance between the most developed countries on several networks actually decreases in time, —which we consider as a proof of globalization. An empirical law is found for the evolution after 1990, similar to that found in flux creep. The optimal observation time window size is found ?15 years.

Mi?kiewicz, Janusz; Ausloos, Marcel

2008-11-01

411

Correlated optical measurements and plasmon mapping of silver nanorods  

SciTech Connect

Plasmonics is a rapidly growing field, yet imaging of the plasmonic modes in complex nanoscale architectures is extremely challenging. Here we obtain spatial maps of the localized surface plasmon modes of high-aspect-ratio silver nanorods using electron energy loss spectroscopy (EELS) and correlate to optical data and classical electrodynamics calculations from the exact same particles. EELS mapping is thus demonstrated to be an invaluable technique for elucidating complex and overlapping plasmon modes.

Guiton, Beth S [ORNL; Iberi, Vighter [University of Tennessee, Knoxville (UTK); Li, Shuzhou [Nanyang Technological University; Leonard, Donovan N [ORNL; Parish, Chad M [ORNL; Kotula, Paul G [Sandia National Laboratories (SNL); Varela del Arco, Maria [ORNL; Schatz, George C. [Northwestern University, Evanston; Pennycook, Stephen J [ORNL; Camden, Jon P [University of Tennessee, Knoxville (UTK)

2011-01-01

412

Reproducing spacecraft measurements of magnetic correlations in the solar wind  

NASA Astrophysics Data System (ADS)

Analytical models for magnetic turbulence are an important ingredient in the theory of field line wandering and cosmic ray diffusion. In previous investigations, a so-called slab/2D model has been used. In the present article, we develop a more general analytical model for magnetic turbulence. This model is then compared with solar wind observations. We investigate numerically the possibility to explain the maltese cross structure of the correlation function of solar wind turbulence with this model.

Weinhorst, B.; Shalchi, A.

2010-03-01

413

Correlation between electrochemical impedance and noise measurements of waterborne coatings  

Microsoft Academic Search

A modified equivalent electric circuit is proposed to establish correspondence between impedance and noise measurements in waterborne coatings in saline media (NaCl). The polarization resistance (Rp) given by the impedance modulus when frequency approaches to zero can not directly be compared with noise measurements since this latter accounts only for the pore resistance of the paint of low barrier protective

M. Hernández; J. Genescá; J. Uruchurtu; A. Barba

2009-01-01

414

Correlating a Motivation-Activation Measure With Media Preference  

Microsoft Academic Search

This study investigates the relationship between individual differences in motivational system responsiveness and preferences for media genres and programming types. The Motivation Activation Measure (MAM) indexed the trait appetitive and aversive motivation system activation of 206 college-aged participants who subsequently responded to self-report scales designed to measure likelihood to use specific genres of television programming, radio formats, and video games.

Robert F. Potter; Sungkyoung Lee; Bridget E. Rubenking

2011-01-01