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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

Measuring Length  

NSDL National Science Digital Library

This article focuses on young students encountering the measurement of length. The article cites examples of key concepts in recognizing length as an attribute and in proper and improper ways to measure length. Conservation and additivity of length, standard and non-standard units, iteration, and the zero point are among the topics presented.

2009-08-01

3

Measurement of the Correlation and Coherence Lengths in Boundary Layer Flight Data  

NASA Technical Reports Server (NTRS)

Wall pressure data acquired during flight tests at several flight conditions are analyzed and the correlation and coherence lengths of the data reported. It is shown how the frequency bandwidth of the analysis biases the correlation length and how the convection of the flow acts to reduce the coherence length. Coherence lengths measured in the streamwise direction appear much longer than would be expected based on classical results for flow over a flat plat.

Palumbo, Daniel L.

2011-01-01

4

Measuring Length  

NSDL National Science Digital Library

Practice measuring length. Play this fun game to work on length. Measure the teddy Next, practice measuring to the nearest 1/2 inch. Measure to 1/2 inches If your ready for a challenge, practice this next game: Measure to 1/4 inches Play the Fish Tales game! *Once you have played all the games, have an adult sign your planner that you practiced these games! You'll ...

Miss Lerdahl

2010-01-26

5

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

6

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

7

Echocardiographic measurements of cardiac dimensions correlate better with body length than with body weight or body surface area.  

PubMed

Looking after children means caring for very small infants up to adult-sized adolescents, with weights ranging from 500 g to more than 100 kg and heights ranging from 25 to more than 200 cm. The available echocardiographic reference data were drawn from a small sample, which did not include preterm infants. Most authors have used body weight or body surface area to predict left ventricular dimensions. The current authors had the impression that body length would be a better surrogate parameter than body weight or body surface area. They analyzed their echocardiographic database retrospectively. The analysis included all available echocardiographic data from 6 June 2001 to 15 December 2011 from their echocardiographic database. The authors included 12,086 of 26,325 subjects documented as patients with normal hearts in their analysis by the examining the pediatric cardiologist. For their analysis, they selected body weight, length, age, and aortic and pulmonary valve diameter in two-dimensional echocardiography and left ventricular dimension in M-mode. They found good correlation between echocardiographic dimensions and body surface area, body weight, and body length. The analysis showed a complex relationship between echocardiographic measurements and body weight and body surface area, whereas body length showed a linear relationship. This makes prediction of echo parameters more reliable. According to this retrospective analysis, body length is a better parameter for evaluating echocardiographic measurements than body weight or body surface area and should therefore be used in daily practice. PMID:24894894

Motz, R; Schumacher, M; Nürnberg, J; Viemann, M; Grafmüller, S; Fiedler, K; Claus, M; Kronberg, K

2014-12-01

8

Measuring Crack Length in Coarse Grain Ceramics  

NASA Technical Reports Server (NTRS)

Due to a coarse grain structure, crack lengths in precracked spinel specimens could not be measured optically, so the crack lengths and fracture toughness were estimated by strain gage measurements. An expression was developed via finite element analysis to correlate the measured strain with crack length in four-point flexure. The fracture toughness estimated by the strain gaged samples and another standardized method were in agreement.

Salem, Jonathan A.; Ghosn, Louis J.

2010-01-01

9

Experimental study on the correlation lengths of the statistical dynamical theory of X-ray diffraction by measurements of integrated intensities from silicon crystals with dislocations.  

PubMed

X-ray integrated intensities J were measured from Si single crystals containing dislocations as a function of crystal thickness using Mo Kalpha radiation. The thickness dependence of J was compared with the statistical dynamical theory of Kato [Acta Cryst. (1980), A36, 763-769, 770-778], which contains three parameters: the static Debye-Waller factor E, the correlation length tau for the phase factor and the correlation length Gamma for the wave-field amplitudes. These three parameters are absolutely required to interpret the experimental data in contrast to the case of gamma-ray experiments in which J can be described by the parameter E alone. For our specimens, the ranges of the fitted values of tau and Gamma are 0.003-0.108 microm and 2.4-7.3 microm, respectively, depending on the reflection plane and the crystal perfection. This fact indicates that the assumption made in Kato's original theory, that Gamma is proportional to the extinction distance, should be abandoned. The reason for which the two correlation lengths can be neglected in the gamma-ray experiments is clarified. PMID:11752764

Sakaki, Daisuke; Takama, Toshihiko

2002-01-01

10

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

PubMed Central

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

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

2014-01-01

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

Fluorescence Correlation Spectroscopy Measurements of the Membrane Protein TetA in Escherichia coli Suggest Rapid Diffusion at Short Length Scales  

PubMed Central

Structural inhomogeneities in biomembranes can lead to complex diffusive behavior of membrane proteins that depend on the length or time scales that are probed. This effect is well studied in eukaryotic cells, but has been explored only recently in bacteria. Here we used fluorescence recovery after photobleaching (FRAP) and fluorescence correlation spectroscopy (FCS) to study diffusion of the membrane protein TetA-YFP in E. coli. We find that the diffusion constant determined from FRAP is comparable to other reports of inner membrane protein diffusion constants in E. coli. However, FCS, which probes diffusion on shorter length scales, gives a value that is almost two orders of magnitude higher and is comparable to lipid diffusion constants. These results suggest there is a population of TetA-YFP molecules in the membrane that move rapidly over short length scales (? 400 nm) but move significantly more slowly over the longer length scales probed by FRAP. PMID:23119068

Chow, David; Guo, Lin; Gai, Feng; Goulian, Mark

2012-01-01

13

Dynamic Correlation Length Scales under Isochronal Conditions  

E-print Network

The origin of the dramatic changes in the behavior of liquids as they approach their vitreous state - increases of many orders of magnitude in transport properties and dynamic time scales - is a major unsolved problem in condensed matter. These changes are accompanied by greater dynamic heterogeneity, which refers to both spatial variation and spatial correlation of molecular mobilities. The question is whether the changing dynamics is coupled to this heterogeneity; that is, does the latter cause the former? To address this we carried out the first nonlinear dielectric experiments at elevated hydrostatic pressures on two liquids, to measure the third-order harmonic component of their susceptibilities. We extract from this the number of dynamically correlated molecules for various state points, and find that the dynamic correlation volume for non-associated liquids depends primarily on the relaxation time, sensibly independent of temperature and pressure. We support this result by molecular dynamic simulations showing that the maximum in the four-point dynamic susceptibility of density fluctuations varies less than 10% for molecules that do not form hydrogen bonds. Our findings are consistent with dynamic heterogeneity serving as the principal control parameter for the slowing down of molecular motions in supercooled materials.

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

2014-10-02

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

Precise Measurement of Effective Focal Length  

NASA Technical Reports Server (NTRS)

Computerized instrument measures effective focal lengths to 0.01 percent accuracy. Laser interferometers measure mirror angle and stage coordinate y in instrument for accurate measurment of focal properties of optical systems. Operates under computer control to measure effective focal length, focal surface shape, modulation transfer function, and astigmatism.

Wise, T. D.; Young, J. B.

1983-01-01

16

Ozone Correlative Measurements Workshop  

NASA Technical Reports Server (NTRS)

A study was conducted to determine the necessary parameters for the correlation of data on Earth ozone. Topics considered were: (1) measurement accuracy; (2) equipment considerations (SBUV); and (3) ground based measurements to support satellite data.

Hilsenrath, E. (editor)

1985-01-01

17

Marine Bi 4iofy LENGTH MEASUREMENTS  

E-print Network

« This information is deemed important chiefly because of the value of year-to-year changes in lengths of fishMarine Bi 4iofy LENGTH MEASUREMENTS OF LAKE YELLOWSTONE TROUT WOODS HOLE, WASS SPECIAL SCIENTIFIC clarid lewisi) on Yellowstone Lake and its tributaries since 1936. Prior to that year, considerable

18

Sonographic Measurement of Fetal Ear Length in Turkish Women with a Normal Pregnancy  

PubMed Central

Background: Abnormal fetal ear length is a feature of chromosomal disorders. Fetal ear length measurement is a simple measurement that can be obtained during ultrasonographic examinations. Aims: To develop a nomogram for fetal ear length measurements in our population and investigate the correlation between fetal ear length, gestational age, and other standard fetal biometric measurements. Study Design: Cohort study. Methods: Ear lengths of the fetuses were measured in normal singleton pregnancies. The relationship between gestational age and fetal ear length in millimetres was analysed by simple linear regression. In addition, the correlation of fetal ear length measurements with biparietal diameter, head circumference, abdominal circumference, and femur length were evaluated.Ear length measurements were obtained from fetuses in 389 normal singleton pregnancies ranging between 16 and 28 weeks of gestation. Results: A nomogram was developed by linear regression analysis of the parameters ear length and gestational age. Fetal ear length (mm) = y = (1.348 X gestational age)?12.265), where gestational ages is in weeks. A high correlation was found between fetal ear length and gestational age, and a significant correlation was also found between fetal ear length and the biparietal diameter (r=0.962; p<0.001). Similar correlations were found between fetal ear length and head circumference, and fetal ear length and femur length. Conclusion: The results of this study provide a nomogram for fetal ear length. The study also demonstrates the relationship between ear length and other biometric measurements.

Özdemir, Mucize Eriç; Uzun, I??l; Karahasano?lu, Ay?e; Aygün, Mehmet; Ak?n, Hale; Yaz?c?o?lu, Fehmi

2014-01-01

19

Acyl Chain Length of Phosphatidylserine Is Correlated with Plant Lifespan  

PubMed Central

Plant lifespan is affected by factors with genetic and environmental bases. The laws governing these two factors and how they affect plant lifespan are unclear. Here we show that the acyl chain length (ACL) of phosphatidylserine (PS) is correlated with plant lifespan. Among the detected eight head-group classes of membrane lipids with lipidomics based on triple quadrupole tandem mass spectrometry, the ACL of PS showed high diversity, in contrast to the ACLs of the other seven classes, which were highly conserved over all stages of development in all plant species and organs and under all conditions that we studied. Further investigation found that acyl chains of PS lengthened during development, senescence, and under environmental stresses and that increasing length was accelerated by promoted- senescence. The acyl chains of PS were limited to a certain carbon number and ceased to increase in length when plants were close to death. These findings suggest that the ACL of PS can count plant lifespan and could be a molecular scale ruler for measuring plant development and senescence. PMID:25058060

Tian, Xuejun; Li, Weiqi

2014-01-01

20

Acyl chain length of phosphatidylserine is correlated with plant lifespan.  

PubMed

Plant lifespan is affected by factors with genetic and environmental bases. The laws governing these two factors and how they affect plant lifespan are unclear. Here we show that the acyl chain length (ACL) of phosphatidylserine (PS) is correlated with plant lifespan. Among the detected eight head-group classes of membrane lipids with lipidomics based on triple quadrupole tandem mass spectrometry, the ACL of PS showed high diversity, in contrast to the ACLs of the other seven classes, which were highly conserved over all stages of development in all plant species and organs and under all conditions that we studied. Further investigation found that acyl chains of PS lengthened during development, senescence, and under environmental stresses and that increasing length was accelerated by promoted- senescence. The acyl chains of PS were limited to a certain carbon number and ceased to increase in length when plants were close to death. These findings suggest that the ACL of PS can count plant lifespan and could be a molecular scale ruler for measuring plant development and senescence. PMID:25058060

Li, Yan; Zheng, Guowei; Jia, Yanxia; Yu, Xiaomei; Zhang, Xudong; Yu, Buzhu; Wang, Dandan; Zheng, Yanling; Tian, Xuejun; Li, Weiqi

2014-01-01

21

Extracting the dynamic correlation length of actin networks from microrheology experiments  

E-print Network

The mechanical properties of polymer gels based on cytoskeleton proteins (e.g. actin) have been studied extensively due to their significant role in biological cell motility and in maintaining the cell's structural integrity. Microrheology is the natural method of choice for such studies due to its economy in sample volume, its wide frequency range, and its spatial sensitivity. In microrheology, the thermal motion of tracer particles embedded in a complex fluid is used to extract the fluid's viscoelastic properties. Comparing the motion of a single particle to the correlated motion of particle pairs, it is possible to extract viscoelastic properties at different length scales. In a recent study, a crossover between intermediate and bulk response of complex fluids was discovered in microrheology measurements of reconstituted actin networks. This crossover length was related to structural and mechanical properties of the networks, such as their mesh size and dynamic correlation length. Here we capitalize on this result giving a detailed description of our analysis scheme, and demonstrating how this relation can be used to extract the dynamic correlation length of a polymer network. We further study the relation between the dynamic correlation length and the structure of the network, by introducing a new length scale, the average filament length, without altering the network's mesh size. Contrary to the prevailing assumption, that the dynamic correlation length is equivalent to the mesh size of the network, we find that the dynamic correlation length increases once the filament length is reduced below the crossover distance.

Adar Sonn-Segev; Anne Bernheim-Groswasser; Yael Roichman

2014-08-21

22

Carbon Nanotubes: Measuring Dispersion and Length  

SciTech Connect

Advanced technological uses of single-wall carbon nanotubes (SWCNTs) rely on the production of single length and chirality populations that are currently only available through liquid phase post processing. The foundation of all of these processing steps is the attainment of individualized nanotube dispersion in solution; an understanding of the collodial properties of the dispersed SWCNTs can then be used to designed appropriate conditions for separations. In many instances nanotube size, particularly length, is especially active in determining the achievable properties from a given population, and thus there is a critical need for measurement technologies for both length distribution and effective separation techniques. In this Progress Report, we document the current state of the art for measuring dispersion and length populations, including separations, and use examples to demonstrate the desirability of addressing these parameters.

Fagan, Jeffrey A.; Bauer, Barry J.; Hobbie, Erik K.; Becker, Matthew L.; Hight-Walker, Angela; Simpson, Jeffrey R.; Chun, Jaehun; Obrzut, Jan; Bajpai, Vardhan; Phelan, Fred R.; Simien, Daneesh; Yeon Huh, Ji; Migler, Kalman B.

2011-03-01

23

Telomere length correlates with life span of dog breeds.  

PubMed

Telomeric DNA repeats are lost as normal somatic cells replicate. When telomeres reach a critically short length, a DNA damage signal is initiated, inducing cell senescence. Some studies have indicated that telomere length correlates with mortality, suggesting that telomere length contributes to human life span; however, other studies report no correlation, and thus the issue remains controversial. Domestic dogs show parallels in telomere biology to humans, with similar telomere length, telomere attrition, and absence of somatic cell telomerase activity. Using this model, we find that peripheral blood mononuclear cell (PBMC) telomere length is a strong predictor of average life span among 15 different breeds (p < 0.0001), consistent with telomeres playing a role in life span determination. Dogs lose telomeric DNA ~10-fold faster than humans, which is similar to the ratio of average life spans between these species. Breeds with shorter mean telomere lengths show an increased probability of death from cardiovascular disease, which was previously correlated with short telomere length in humans. PMID:23260664

Fick, Laura J; Fick, Gordon H; Li, Zichen; Cao, Eric; Bao, Bo; Heffelfinger, Doug; Parker, Heidi G; Ostrander, Elaine A; Riabowol, Karl

2012-12-27

24

Determining Correlation and Coherence Lengths in Turbulent Boundary Layer Flight Data  

NASA Technical Reports Server (NTRS)

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

2012-01-01

25

Correlative Measurements Program  

NASA Technical Reports Server (NTRS)

The GSFC Correlative Measurements Program at the Wallops Flight Facility was represented on the Satellite/Satellite Intercomparisons Working Group. The Correlative Measurements Program uses the Rocket Ozonesonde (ROCOZ-A) and the Electrochemical Concentration Cell (ECC) balloon borne ozonesonde to measure the vertical profile of ozone amount in the atmosphere. The balloon work is described in a separate report. The ROCOZ-A instrument was used for many years to provide in situ truth data for various satellite ozone measuring systems, such as SBUV on Nimbus-7, SAGE-II, SBUV-II on the NOAA series of polar orbiting satellites, SME, LIMS, etc. The particular data sets of interest to the Ozone Trends Panel Working Group were collected at Natal, Brazil. The major results produced for and used by the Ozone Trends Panel are shown. The ROCOZ-A average ozone density profile is plotted versus altitude on the left. ECC ozonesondes were used for the portion of the profile below 20 km, the lower limit for ROCOZ-A. The difference between SAGE-II and ROCOZ-A average density profiles is shown.

Parsons, C. L.

1988-01-01

26

Correcting correlation function measurements  

NASA Astrophysics Data System (ADS)

Correlation functions measured as a function of ?? ,?? have emerged as a powerful tool to study the dynamics of particle production in nuclear collisions at high energy. They are however subject, like any other observables, to instrumental effects which must be properly accounted for to extract meaningful physics results. We compare the merits of several techniques used towards measurement of these correlation functions in nuclear collisions. We discuss and distinguish the effects of finite acceptance, and detection efficiency that may vary with collision parameters such as the position of the event in the detector and the instantaneous luminosity of the beam. We focus in particular on instrumental effects which break the factorization of the particle pair detection efficiency, and describe a technique to recover the robustness of correlation observables. We finally introduce a multidimensional weight method to correct for efficiencies that vary simultaneously with particle pseudo rapidity, azimuthal angle, transverse momentum, and the collision vertex position. The method can be generalized to account for any number of "event variables" that may break the factorability of the pair efficiency.

Ravan, Shantam; Pujahari, Prabhat; Prasad, Sidharth; Pruneau, Claude A.

2014-02-01

27

Correlation Lengths of Red and Blue Galaxies: A New Cosmic Ruler  

E-print Network

A comparison of the correlation lengths of red galaxies with blue can provide a new cosmic ruler. Using 269,000 galaxies from the SDSS DR6 survey, I show that the 3D correlation length averaged over many clusters remains very nearly constant at Lo=4.797+/-0.024 Mpc/h from small redshifts out to redshifts of 0.5. This serves as a new measure of cosmic length scales as well as a means of testing the standard cosmological model that is almost free of selection biases. The cluster number density also appears to remain constant over this redshift range.

Michael J. Longo

2008-10-22

28

Bedside prediction of airway length by measuring upper incisor manubrio-sternal joint length  

PubMed Central

Background: Malpositioning of endotracheal tube may lead to serious complications like endobronchial intubation or accidental extubation. Using anatomical measurements for prediction of airway length would be more practical in resource constrained settings. Materials and Methods: One hundred adult patients of American Society of Anesthesiologists (ASA) grade 1 or 2, without any evidence of difficult airway, were randomly allocated to two cohorts — a model cohort of 70 (50 males) and test cohort of 30 (20 males) subjects. Height, the straight length from the upper incisor to manubrio-sternal joint in fully extended head position (IncManustL), the length from upper incisor to the carina in neutral head position (IncCarinaL), and degree of neck extension were measured in all subjects. Relationship between the two lengths in the model cohort was explored by Pearson's coefficient (r). Predictions were made for subjects in the test cohort and actual and predicted values assessed for agreement using intra-class correlation coefficient (ICC). Results: Good agreement was found between IncManustL and IncCarinaL for both male (r = 0.69) and female (r = 0.54) subjects. Multiple regression analysis suggested height to be another significant predictor, unlike age, weight, and neck extension. The gender-specific regression equations were used to predict IncCarinaL for the test cohort. ICC for absolute agreement between the actual and predicted values was 0.723 (95% CI 0.495-0.858). Conclusions: It is possible to predict airway length in adult Indian subjects by making two simple anatomical measurements, namely stature and incisor manubrio-sternal joint length. PMID:24803755

Mukherjee, Sudipta; Ray, Manjushree; Pal, Rita

2014-01-01

29

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

30

Automatic detection and measurement of femur length from fetal ultrasonography  

NASA Astrophysics Data System (ADS)

Femur bone length is used in the assessment of fetal development and in the prediction of gestational age (GA). In this paper, we present a completely automated two-step method for identifying fetal femur and measuring its length from 2D ultrasound images. The detection algorithm uses a normalized score premised on the distribution of anatomical shape, size and presentation of the femur bone in clinically acceptable scans. The measurement process utilizes a polynomial curve fitting technique to determine the end-points of the bone from a 1D profile that is most distal from the transducer surface. The method has been tested with manual measurements made on 90 third trimester femur images by two radiologists. The measurements made by the experts are strongly correlated (Pearson's coefficient = 0.95). Likewise, the algorithm estimate is strongly correlated with expert measurements (Pearson's coefficient = 0.92 and 0.94). Based on GA estimates and their bounds specified in Standard Obstetric Tables, the GA predictions from automated measurements are found to be within +/-2SD of GA estimates from both manual measurements in 89/90 cases and within +/-3SD in all 90 cases. The method presented in this paper can be adapted to perform automatic measurement of other fetal limbs.

Mukherjee, Prateep; Swamy, Gokul; Gupta, Madhumita; Patil, Uday; Krishnan, Kajoli Banerjee

2010-03-01

31

Local-hybrid functional based on the correlation length  

NASA Astrophysics Data System (ADS)

Local-hybrid functionals involve position-dependent mixing of Hartree-Fock and density-functional exchange, which should allow improved performance relative to conventional hybrids by reducing the inherent delocalization error and improving the long-range behaviour. Herein, the same-spin correlation length, obtained from the Fermi-hole radius, is used as the mixing parameter. The performance of the resulting local-hybrid functional is assessed for standard thermochemical and kinetics benchmarks. The local hybrid is shown to perform significantly better than the corresponding global hybrid in almost all cases.

Johnson, Erin R.

2014-09-01

32

Analytical forms of correlation functions and length scales of astrophysical turbulence  

NASA Astrophysics Data System (ADS)

In this article correlation-functions, correlation-scales, and field line diffusion coefficients of magnetic turbulence are discussed. For the slab turbulence model these parameters are calculated analytically for different forms of the wave-spectrum of the magnetic fluctuations. It is also demonstrated in this article that the definition of the correlation-length used previously yields infinity in some cases. Furthermore, correlation-functions and correlation-scales are calculated analytically for the well-established slab/2D composite model. It is demonstrated that the 2D correlation function decays much slower than the slab correlation function. These results are essential for understanding previous theoretical results of superdiffusive field line random walk and very recent spacecraft measurements of magnetic correlations in the solar wind.

Shalchi, A.

2008-06-01

33

Length of adaptive walk on uncorrelated and correlated fitness landscapes  

NASA Astrophysics Data System (ADS)

We consider the adaptation dynamics of an asexual population that walks uphill on a rugged fitness landscape which is endowed with a large number of local fitness peaks. We work in a parameter regime where only those mutants that are a single mutation away are accessible, as a result of which the population eventually gets trapped at a local fitness maximum and the adaptive walk terminates. We study how the number of adaptive steps taken by the population before reaching a local fitness peak depends on the initial fitness of the population, the extreme value distribution of the beneficial mutations, and correlations among the fitnesses. Assuming that the relative fitness difference between successive steps is small, we analytically calculate the average walk length for both uncorrelated and correlated fitnesses in all extreme value domains for a given initial fitness. We present numerical results for the model where the fitness differences can be large and find that the walk length behavior differs from that in the former model in the Fréchet domain of extreme value theory. We also discuss the relevance of our results to microbial experiments.

Seetharaman, Sarada; Jain, Kavita

2014-09-01

34

Length of adaptive walk on uncorrelated and correlated fitness landscapes.  

PubMed

We consider the adaptation dynamics of an asexual population that walks uphill on a rugged fitness landscape which is endowed with a large number of local fitness peaks. We work in a parameter regime where only those mutants that are a single mutation away are accessible, as a result of which the population eventually gets trapped at a local fitness maximum and the adaptive walk terminates. We study how the number of adaptive steps taken by the population before reaching a local fitness peak depends on the initial fitness of the population, the extreme value distribution of the beneficial mutations, and correlations among the fitnesses. Assuming that the relative fitness difference between successive steps is small, we analytically calculate the average walk length for both uncorrelated and correlated fitnesses in all extreme value domains for a given initial fitness. We present numerical results for the model where the fitness differences can be large and find that the walk length behavior differs from that in the former model in the Fréchet domain of extreme value theory. We also discuss the relevance of our results to microbial experiments. PMID:25314469

Seetharaman, Sarada; Jain, Kavita

2014-09-01

35

[Measurement of penile length in children and its significance].  

PubMed

Nowadays, more and more parents are paying increasing attention to the penile length of their children. At present, the methods of measuring penile length mainly include manual measurement and ultrasonography. The former can be used to measure the flaccid, stretched and erected penile lengths, and its use for measuring the stretched penile length has been internationally accepted for its precise definition, unified description, and high repeatability. The latter, as a new method, is being gradually accepted for its imaging visualization and measurement accuracy. This article reviews different measurements of penile length in the mainstream literature of recent years, with an analysis of their advantages and disadvantages. PMID:24386865

Guo, Li-Li; Tang, Da-Xing

2013-09-01

36

Admission Norton scale scores (ANSS) correlate with rehabilitation outcome and length in elderly patients with deconditioning.  

PubMed

We sought to determine if admission Norton scale scores (ANSS) used for evaluating pressure ulcer risk also correlate with rehabilitation outcome and length in elderly patients with deconditioning. This was a retrospective study conducted in a geriatric department between June 2008 and June 2010. The medical charts of consecutive elderly (?65 years) patients admitted for rehabilitation due to deconditioning were studied for the following measurements: ANSS, admission albumin serum levels, mini-mental status examination (MMSE) scores, discharge walking functional independence measure (FIM) scores, discharge transfer FIM scores, and rehabilitation length. The cohort included 152 patients: 79 (52%) females and 73 (48%) males. Mean age was 83.6±6.5 years. The three most common causes of deconditioning were pneumonia, congestive heart failure exacerbation, and falls. ANSS correlated with discharge walking FIM scores (r=0.32; p=0.003), discharge transfer FIM scores (r=0.30; p=0.005), and length of rehabilitation (r=-0.37; p<0.0001), following adjustment for age, albumin serum levels, and MMSE scores. Linear regression analysis showed that ANSS were independently associated with discharge walking FIM scores (p=0.004), discharge transfer FIM scores (p=0.006), and rehabilitation length (p<0.0001). We conclude that the Norton scoring system may be used for predicting the outcome and the length of rehabilitation in elderly patients with deconditioning. PMID:21570133

Guy, Noam; Lerman, Yaffa; Justo, Dan

2012-01-01

37

On the Relationship Between Correlation Length and Rate of Fluctuation of Random Fields  

Microsoft Academic Search

We show that the correlation length of a random field, modelled as a real wide-sense stationary stochastic process, defines a lower limit on the average squared rate of fluctuation of the field. For a sample-continuous process, the uncertainty relation between the correlation length and the spectral bandwidth exhibits a lower limit that depends explicitly on the selected correlation threshold level

Luk R. Arnaut

2007-01-01

38

Computable measure of quantum correlation  

NASA Astrophysics Data System (ADS)

A general state of an system is a classical-quantum state if and only if its associated -correlation matrix (a matrix constructed from the coherence vector of the party , the correlation matrix of the state, and a function of the local coherence vector of the subsystem ), has rank no larger than . Using the general Schatten -norms, we quantify quantum correlation by measuring any violation of this condition. The required minimization can be carried out for the general -norms and any function of the local coherence vector of the unmeasured subsystem, leading to a class of computable quantities which can be used to capture the quantumness of correlations due to the subsystem . We introduce two special members of these quantifiers: The first one coincides with the tight lower bound on the geometric measure of discord, so that such lower bound fully captures the quantum correlation of a bipartite system. Accordingly, a vanishing tight lower bound on the geometric discord is a necessary and sufficient condition for a state to be zero-discord. The second quantifier has the property that it is invariant under a local and reversible operation performed on the unmeasured subsystem, so that it can be regarded as a computable well-defined measure of the quantum correlations. The approach presented in this paper provides a way to circumvent the problem with the geometric discord. We provide some examples to exemplify this measure.

Akhtarshenas, S. Javad; Mohammadi, Hamidreza; Karimi, Saman; Azmi, Zahra

2015-01-01

39

Measurement: Which Unit of Length is Appropriate?  

NSDL National Science Digital Library

In this game, students are given an object such as a diving board or earthwork and are asked to select the appropriate unit for the measurement of the object, including yards, meters, centimeters, inches, and feet. Students select the correct answer from two possibilities. Their answers and the time taken are recorded. This is an excellent resource to help students understand the difference in units of measurement as well as beginning estimation skills.

2008-01-01

40

50 CFR Appendix C to Part 622 - Fish Length Measurements  

Code of Federal Regulations, 2011 CFR

...and Fisheries 10 2011-10-01 2011-10-01 false Fish Length Measurements C Appendix C to Part 622 Wildlife and...SOUTH ATLANTIC Pt. 622, App. C Appendix C to Part 622—Fish Length Measurements ER03JY96.000 Figure 1 of Appendix...

2011-10-01

41

50 CFR Appendix C to Part 622 - Fish Length Measurements  

Code of Federal Regulations, 2012 CFR

...and Fisheries 12 2012-10-01 2012-10-01 false Fish Length Measurements C Appendix C to Part 622 Wildlife and...SOUTH ATLANTIC Pt. 622, App. C Appendix C to Part 622—Fish Length Measurements ER03JY96.000 Figure 1 of Appendix...

2012-10-01

42

50 CFR Appendix C to Part 622 - Fish Length Measurements  

Code of Federal Regulations, 2013 CFR

...and Fisheries 12 2013-10-01 2013-10-01 false Fish Length Measurements C Appendix C to Part 622 Wildlife and...SOUTH ATLANTIC Pt. 622, App. C Appendix C to Part 622—Fish Length Measurements ER17AP13.000...

2013-10-01

43

50 CFR Appendix C to Part 622 - Fish Length Measurements  

Code of Federal Regulations, 2010 CFR

...and Fisheries 8 2010-10-01 2010-10-01 false Fish Length Measurements C Appendix C to Part 622 Wildlife and...SOUTH ATLANTIC Pt. 622, App. C Appendix C to Part 622—Fish Length Measurements ER03JY96.000 Figure 1 of Appendix...

2010-10-01

44

Surface Free Energies, Interfacial Tensions and Correlation Lengths of the ABF Models  

E-print Network

Surface Free Energies, Interfacial Tensions and Correlation Lengths of the ABF Models David L. O. Abstract The surface free energies, interfacial tensions and correlation lengths of the Andrews been established there are various quan- tities of physical interest, such as the surface free energies

Pearce, Paul A.

45

Measuring the Length of a Captured Burmese Python  

USGS Multimedia Gallery

Skip Snow (National Park Service) measures the length of a captured Burmese python (Python molurus) at the South Florida Research Center, Everglades National Park. Photo courtesy of Lori Oberhofer, NPS. ...

2009-10-12

46

An anthropometric study to evaluate the correlation between the occlusal vertical dimension and length of the thumb  

PubMed Central

Background Establishment of proper occlusal vertical dimension (OVD) is one of the important tasks for successful prosthodontic therapy. An ideal method for determining OVD in terms of cost, time, and instrument requirements has been sought in prosthodontics by various investigators. However, no such single method has been formulated. In the current anthropometric study, the relationship of the length of the thumb to the OVD was tested in two ethnic groups of Nepal, Aryans, and Mongoloids. The result of this study can be useful in determining proper OVD in edentulous patients. Aims and objectives The primary aim of the present study was to evaluate the correlation between the length of the thumb and OVD in Aryan and Mongoloid ethnic groups. The secondary aim was to compare the correlation between OVD and other anatomic measurements (eye–ear distance and pupil-to-rima oris distance) in these ethnicities. Materials and methods The OVD, thumb length, eye–ear distance and distance between pupil of eye and rima oris were measured in a total of 500 adult dentulous volunteers. The correlation between OVD and thumb length as well as other anatomic measurements was checked with Pearson’s product moment correlation coefficient. Linear regression analysis was performed to determine the relationship of OVD to the length of the thumb. Results The thumb length was significantly (P?0.05) correlated with strong and positive values (Pearson’s coefficient =0.874 in the whole population, 0.826 in Aryans, and 0.944 in Mongoloids). Regression analysis showed that thumb length was significantly related to OVD in both ethnic groups. Conclusion Within the limitations of the present study, the result implies that thumb length can be used as an adjunct for establishing OVD in the edentulous patients.

Basnet, Bishal Babu; Parajuli, Prakash Kumar; Singh, Raj Kumar; Suwal, Pramita; Shrestha, Pragya; Baral, Dharanidhar

2015-01-01

47

Correlations between Muscle Activities and Strap Length and Types of School Bag during Walking.  

PubMed

[Purpose] The purpose of this study was to examine correlations between muscle activities and strap length and type of the school bag during walking. [Subjects and Methods] The subjects of this study were 20 healthy students. An 8-channel electromyograph (8-EMG) (Pocket EMG, BTS, Italy) was used to measure the muscle activities of the right upper trapezius, left upper trapezius, right erector spinae and left erector spinae during walking with the bag. The collected data were analyzed using Kendall's coefficient of concordance. [Results] The muscle activities of the right upper trapezius, left upper trapezius, right erector spinae and left erector spinae were significantly higher when walking with a shoulder bag than when walking with a backpack. No significant correlations were found between muscle activities and strap lengths of the bag. [Conclusion] While carrying a bag, the activities of the trunk muscles were influenced more by the type of the bag than by the strap length. These results indicate that a backpack is a better method of carrying a load than a shoulder bag. PMID:25540502

Yoon, Jung-Gyu

2014-12-01

48

Correlations between Muscle Activities and Strap Length and Types of School Bag during Walking  

PubMed Central

[Purpose] The purpose of this study was to examine correlations between muscle activities and strap length and type of the school bag during walking. [Subjects and Methods] The subjects of this study were 20 healthy students. An 8-channel electromyograph (8-EMG) (Pocket EMG, BTS, Italy) was used to measure the muscle activities of the right upper trapezius, left upper trapezius, right erector spinae and left erector spinae during walking with the bag. The collected data were analyzed using Kendall’s coefficient of concordance. [Results] The muscle activities of the right upper trapezius, left upper trapezius, right erector spinae and left erector spinae were significantly higher when walking with a shoulder bag than when walking with a backpack. No significant correlations were found between muscle activities and strap lengths of the bag. [Conclusion] While carrying a bag, the activities of the trunk muscles were influenced more by the type of the bag than by the strap length. These results indicate that a backpack is a better method of carrying a load than a shoulder bag.

Yoon, Jung-Gyu

2014-01-01

49

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. PMID:17199890

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

2007-01-01

50

Measurement accuracy and reliability of tooth length on conventional and CBCT reconstructed panoramic radiographs  

PubMed Central

INTRODUCTION: This in vivo study assessed accuracy and reliability of tooth length measurements obtained from conventional panoramic radiographs and CBCT panoramic reconstructions to that of a digital caliper (gold standard). METHODS: The sample consisted of subjects who had CBCT and conventional panoramic radiographic imaging and who required maxillary premolar extraction for routine orthodontic treatment. A total of 48 teeth extracted from 26 subjects were measured directly with digital calipers. Radiographic images were scanned and digitally measured in Dolphin 3D software. Accuracy of tooth length measurements made by CBCT panoramic reconstructions, conventional panoramic radiographs and digital caliper (gold standard) were compared to each other by repeated measures one-way ANOVA with Bonferroni correction and by single measures intraclass correlation coefficient. RESULTS: Repeated root length measures with digital calipers, panoramic radiographs and CBCT constructed panoramic-like images were all individually highly reliable. Compared to the caliper (gold standard), tooth measurements obtained from conventional panoramic radiographs were on average 6.3 mm (SD = 2.0 mm) longer, while tooth measurements from CBCT panoramic reconstructions were an average of 1.7 mm (SD = 1.2 mm) shorter. CONCLUSIONS: In comparison to actual tooth lengths, conventional panoramic radiographs were relatively inaccurate, overestimating the lengths by 29%, while CBCT panoramic reconstructions underestimated the lengths by 4%.

Flores-Mir, Carlos; Rosenblatt, Mark R; Major, Paul W.; Carey, Jason P.; Heo, Giseon

2014-01-01

51

Flow and Transport Characteristics of Fracture Networks with Length-Aperture Correlation  

NASA Astrophysics Data System (ADS)

Predictions of fluid flow and solute transport in fractured rock masses typically rely on numerical simulations that incorporate uncertainty in fracture attributes such as location, orientation, length and aperture. These attributes of fracture networks are generally assumed uncorrelated. Given that the propagation of fractures is a systematic response to a stress field acting on a rock mass, it is natural to assume that correlations should exist between various fracture attributes. Of the potential correlations that may exist, a positive correlation between fracture length and aperture, supported by field observations and opening-mode fracture propagation models, most likely exerts the greatest control on fluid flow and solute transport. We test the influence of a length-aperture correlation by implementing a physically-realistic correlation model for opening-mode fractures. Results from Monte Carlo simulations of random fracture networks, generated according to power-law distributions of fracture length and varying degrees of fracture density, are used to illustrate the influence of aperture-length correlations on fluid flow and solute transport. Metrics used to compare fluid flow for length-aperture correlated and uncorrelated networks include the magnitude of global flow and scales at which a representative elementary volume is reached. Transport comparisons for correlated and uncorrelated networks are based on conservative solute breakthrough, including characteristics of fast particle arrivals and late-time tailing. Preliminary results indicate that length-aperture correlations produce a flow-focused network structure that both increases the global quantity of fluid transmitted through the networks and promotes rapid transport.

Reeves, D. M.; Parashar, R.

2009-12-01

52

Measurement of Trap Length for an Optical Trap  

NASA Technical Reports Server (NTRS)

The trap length along the beam axis for an optical trap formed with an upright, oil-immersion microscope was measured. The goals for this effort were twofold. It was deemed useful to understand the depth to which an optical trap can reach for purposes of developing a tool to assist in the fabrication of miniature devices. Additionally, it was desired to know whether the measured trap length favored one or the other of two competing theories to model an optical trap. The approach was to trap a microsphere of known size and mass and raise it from its initial trap position. The microsphere was then dropped by blocking the laser beam for a pre-determined amount of time. Dropping the microsphere in a free-fall mode from various heights relative to the coverslip provides an estimate of how the trapping length changes with depth in water in a sample chamber on a microscope slide. While it was not possible to measure the trap length with sufficient precision to support any particular theory of optical trap formation, it was possible to find regions where the presence of physical boundaries influenced optical traps, and determine that the trap length, for the apparatus studied, is between 6 and 7 m. These results allow more precise control using optical micromanipulation to assemble miniature devices by providing information about the distance over which an optical trap is effective.

Wrbanek, Susan Y.

2009-01-01

53

Cytosine Usage Modulates the Correlation between CDS Length and CG Content in Prokaryotic Genomes  

E-print Network

Cytosine Usage Modulates the Correlation between CDS Length and CG Content in Prokaryotic Genomes empirically by prokaryotic genomes. How- ever, the correlation is weak for a number of species, with 4 species in long CDSs. Empirical data from prokaryotic genomes lend strong support for this new hypothesis

Xia, Xuhua

54

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

55

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

56

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 {angstrom} at the Linac Coherent Light Source (LCLS). By disrupting the FEL 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, Daniel; Brachmann, A.; Decker, F.J.; Ding, Y.; Dowell, D.; Emma, P.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, P.; Huang, Z.; Iverson, R.; Loos, H.; Miahnahri, A.; Nuhn, H.D.; Turner, J.; Welch, J.; White, W.; Wu, J.; Xiang, D.; Yocky, G.; /SLAC /LBL, Berkeley; ,

2010-07-30

57

Negative correlation between age of subjects and length of the appendix in Bangladeshi males  

PubMed Central

Introduction The anatomy of the vermiform appendix shows variations in its macroscopic dimensions some of which have potential to influence the clinical aspects of the appendix. Anatomical studies on the appendix using people in Bangladesh as a sample are limited and fall short of producing any standardized anthropometric data. This study is predominantly a cross-sectional observational study which also uses some statistical analysis to understand the relationships amongst variables. Material and methods Fifty-six adult male postmortem appendices and adnexa were examined for macroscopic features. Possible interrelationships among the variables were assessed through statistical analysis. The age of the samples ranged from 18 to 67 years. The most common position of the appendix was retrocolic (53.57%) followed by pelvic (30.35%), postileal (12.5%), and subcaecal (3.5%). Results In most cases (62.5%) the mesoappendix did not reach the tip of the appendix. The appendicular length varied from 6.00 cm to 16.30 cm with mean (± SD) and median value of 10.21 ±2.50 cm and 10.00 cm respectively. The base of the appendix was 1.90 to 3.80 cm away from the ileocaecal junction. The other macroscopic measurements of the appendix were taken at the base, at the midzone and at the tip of the appendix and the mean of the three measurements was considered as the overall value. Thus, the overall external diameter varied between 0.32 cm and 0.83 cm. Assessment of possible correlations amongst different variables revealed a significant negative correlation between the age of the subjects and the length of the appendix. Conclusions The data of the present study may provide a baseline along with some previous data in the standardization of the anthropometric information regarding the vermiform appendix of Bangladeshi males. PMID:23515519

Bakar, Sheikh Muhammad Abu; Shamim, Manjare; Alam, Gazi Mahabubul

2013-01-01

58

Universal measurement of quantum correlations of radiation  

E-print Network

A measurement technique is proposed which, in principle, allows one to observe the general space-time correlation properties of a quantized radiation field. Our method, called balanced homodyne correlation measurement, unifies the advantages of balanced homodyne detection with those of homodyne correlation measurements.

E. Shchukin; W. Vogel

2006-05-16

59

Axial and peripheral eye length measured with optical low coherence reflectometry.  

PubMed

An optical low-coherence reflectometer (OLCR device) is described that allows the precise and noncontact measurement of eye length. The device measures eye length both on-axis and off-axis, thus enabling the determination of eye shape, an ocular parameter thought to be important in the development of refractive error. It is essential for several applications in ophthalmology and vision science. This improved OLCR device operates using a single-beam interferometer with a beam deflection mechanism that allows the precise measurement of eye length along the visual axis and within 15 deg horizontally and vertically from the fovea. The validity of this instrument and its revised software is evaluated by measuring the reproducibility of axial length results in an adult eye and an artificial eye, and by correlating axial eye length measured in a group of ten adult eyes with axial eye length obtained with A-scan ultrasound in the same eyes. The precision obtained with adult subjects is compared with that obtained with children. PMID:14563204

Schmid, Gregor F

2003-10-01

60

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. PMID:15252971

Nudds, Robert L; Spencer, Karen A

2004-01-01

61

Measurement of ?? Scattering Lengths from K and K3? Decays  

NASA Astrophysics Data System (ADS)

In the last few years it has become possible to study low energy ?? scattering with high precision in kaon decays, thanks to the high statistics measurements of K???? ( K3?) and K???e? ( K) decays performed by the NA48/2 experiment at the CERN SPS. In K????, at the ?? threshold, the ?? mass spectrum exhibits a Wigner-cusp, from which the scattering lengths a and a are extracted. From the study of K decays a similar precision, but quite independent measurement of a and a can be obtained. The combination of both measurements provides one of the most stringent tests of Chiral Perturbation Theory.

Wanke, R.

2011-01-01

62

Measurements of Correlation-Enhanced Collision Rates  

NASA Astrophysics Data System (ADS)

This talk presents the first detailed experimental measurements of the Salpeter collisional enhancement factor g ( ?) in strongly correlated plasmas. This factor is predicted to enhance the nuclear reaction rate in dense strongly-correlated plasmas, such as in giant planet interiors, brown dwarfs and degenerate stars;footnotetextE.E. Salpeter and H.M. Van Horn, Astrophys. J. 155, 183 (1969). and recent theory establishes that it also applies to the perpendicular-to-parallel collisions in magnetized plasmas described here.footnotetextD.H.E. Dubin, Phys. Rev. Lett. 94, 025002 (2005). The enhancement is caused by plasma screening of the repulsive Coulomb potential between charges, allowing closer collisions for a given particle energy. The enhancement factor is predicted to be large when the plasma correlation parameter ??e^2 /aT is larger than unity, scaling as g ( ?) ˜e^?. The perp-to-parallel collision rate is then ?|= n v b^2 ,( ? ) ,( ?), where I ( ? ) decreases precipitously below ( 8 ?? / 15 ) ? in the highly magnetized regime of ? ??2 ,/ rc1. Our measurementsfootnotetextF. Anderegg et al., Phys. Rev. Lett. 102, 185001 (2009); F. Anderegg et al., Phys. Plasmas 16, 055705 (2009). of ?| in Mg^+ pure ion plasmas are consistent with the predicted Salpeter correlation enhancement, with the comparison limited mainly by systematic spatial variations in the plasma temperature. The plasma temperatures are controlled over the range 4 x10-6 < T < 1eV, with the outer radii being up to 2x hotter. Bulk-averaged collision rates of 1 < ?|< 2 x10^4 sec-1 are measured by 2 techniques: for slow collisions, T| is heated or cooled, and the subsequent relaxation is directly observed; for rapid collisions, sinusoidal modulation of the plasma length at frequency fmod gives maximal heating when fmod = ?|/ 2 ?c (?), where c ( ?) is the specific heat. Two densities are used, 2.0 and 0.12 x10^7 cm-3; the lower density has ˜2.5 x less correlation at any temperature. Experiments clearly show the expected ?|T-3/2 regime at high temperatures, and show the strong I ( ? ) suppression of ?| for b / rc1. At low temperatures and high density, the measured ?| is enhanced by up to g ˜10^12 over the uncorrelated prediction, consistent with the Salpeter-enhanced prediction. At low (uncorrelated) densities, no enhancement is observed. Future experiments may be able to image ``burn fronts'' propagating from hot regions to cold regions.

Driscoll, C. Fred

2009-11-01

63

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

64

Precision Neutron Scattering Length Measurements with Neutron Interferometry  

NASA Astrophysics Data System (ADS)

Since its inception, single-crystal neutron interferometry has often been utilized for precise neutron scattering length, b, measurements. Scattering length data of light nuclei is particularly important in the study of few nucleon interactions as b can be predicted by two + three nucleon interaction (NI) models. As such they provide a critical test of the accuracy 2+3 NI models. Nuclear effective field theories also make use of light nuclei b in parameterizing mean-field behavior. The NIST neutron interferometer and optics facility has measured b to less than 0.8% relative uncertainty in polarized ^3He and to less than 0.1% relative uncertainty in H, D, and unpolarized ^3He. A neutron interferometer consists of a perfect silicon crystal machined such that there are three separate blades on a common base. Neutrons are Bragg diffracted in the blades to produce two spatially separate (yet coherent) beam paths much like an optical Mach-Zehnder interferometer. A gas sample placed in one of the beam paths of the interferometer causes a phase difference between the two paths which is proportional to b. This talk will focus on the latest scattering length measurement for n-^4He which ran at NIST in Fall/Winter 2010 and is currently being analyzed.

Huber, M. G.; Arif, M.; Jacobson, D. L.; Pushin, D. A.; Abutaleb, M. O.; Shahi, C. B.; Wietfeldt, F. E.; Black, T. C.

2011-10-01

65

Axial length measurement techniques in pediatric eyes with cataract  

PubMed Central

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.

2011-01-01

66

Precision Neutron Scattering Length Measurements Using Neutron Interferometry  

NASA Astrophysics Data System (ADS)

The neutron interferometer, pioneered by Werner and Rauch in the 1970's, splits the neutron matter wave into two paths by Bragg diffraction in a perfect silicon crystal, then recombines them coherently to produce a interference signal measured by a neutron counter, thereby directly obtaining an interaction amplitude via the phase shift. It has been used to make famous demonstrations of quantum phenomena that are now found in many textbooks. It is also an ideal instrument for precision measurement of low-energy neutron scattering lengths that are important for developing and testing nuclear potential models and effective field theories, and probing neutron substructure. I will describe previous experiments and the current program at the NIST Neutron Interferometry and Optics Facility.

Wietfeldt, Fred

2008-10-01

67

Compression strain measurement by digital speckle correlation  

Microsoft Academic Search

In this paper, an optimized digital speckle correlation algorithm, named big-window correlation, is proposed to iterate strain directly. Verified by some experiments, the sensitivity and accuracy of the displacement gradient measurement with this method can be improved greatly. Finally, this method was applied to the measurement of the compression strain for polyurethane foam plastics materials. Then the material properties, such

D. Zhang; X. Zhang; G. Cheng

1999-01-01

68

Comparison of the relative telomere length measured in leukocytes and eleven different human tissues.  

PubMed

The relative length of telomeres measured in peripheral blood leukocytes is a commonly used system marker for biological aging and can also be used as a biomarker of cardiovascular aging. However, to what extent the telomere length in peripheral leukocytes reflects telomere length in different organ tissues is still unclear. Therefore, we have measured relative telomere length (rTL) in twelve different human tissues (peripheral blood leukocytes, liver, kidney, heart, spleen, brain, skin, triceps, tongue mucosa, intercostal skeletal muscle, subcutaneous fat, and abdominal fat) from twelve cadavers (age range of 29 week of gestation to 88 years old). The highest rTL variability was observed in peripheral leukocytes, and the lowest variability was found in brain. We found a significant linear correlation between leukocyte rTL and both intercostal muscle (R=0.68, P<0.02) and liver rTL (R=0.60, P<0.05) only. High rTL variability was observed between different organs from one individual. Furthermore, we have shown that even slight DNA degradation (modeled by sonication of genomic DNA) leads to false rTL shortening. We conclude that the rTL in peripheral leukocytes is not strongly correlated with the rTL in different organs. PMID:25428739

Dlouha, D; Maluskova, J; Kralova Lesna, I; Lanska, V; Hubacek, J A

2014-01-01

69

Aging phenotypes in cultured normal human mammary epithelial cells are correlated with decreased telomerase activity independent of telomere length  

PubMed Central

Background Shortening of telomeres, which are essential for maintenance of genomic integrity, is a mechanism commonly associated with the aging process. Here we ascertained whether changes in telomere lengths or telomerase activity correlated with age in normal human mammary epithelial cells (HMEC), or with phenotypes of aging in breast. Accordingly, flow cytometry fluorescence in situ hybridization (flowFISH) was used to determine relative telomere lengths (RTL), and telomerase activity was measured by the telomeric repeat amplification protocol (TRAP), in a collection of 41 primary HMEC strains established from women aged 16 to 91 years. Results RTL measurements of HMEC strains that were heterogeneous with respect to lineage composition revealed no significant associations between telomere length with age, maximum observed population doublings, or with lineage composition of the strains. However, within strains, luminal epithelial and cKit-expressing epithelial progenitor cells that were flow cytometry-enriched from individual HMEC strains exhibited significantly shorter telomeres relative to isogenic myoepithelial cells (P?correlate with RTL. Telomerase activity declined with age; the average age of strains that exhibited TRAP activity was 29.7?±?3.9y, whereas the average age of strains with no detectable TRAP activity was 49.0?±?4.9y (P?correlated with phenotypes of aging previously described in HMEC strains; increased proportions of CD227-expressing luminal epithelial cells (P?correlate with the chronological ages of HMEC strains, whereas decreased telomerase activity correlated with age and with lineage distribution phenotypes characteristic of aging. PMID:23718190

2013-01-01

70

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

E-print Network

Recently a new approach to the determination of dynamic correlation lengths, {\\xi}, for supercooled liquids, based on the properties of the slow (picosecond) vibrational dynamics, was carried out [L. Hong, V.N. Novikov, and A.P. Sokolov, Phys. Rev. E 83, 061508 (2011)]. Although these vibrational measurements are typically conducted well below the glass transition temperature, Tg, the assumption is that the structure of the liquid is frozen at Tg, so that the {\\xi} characterize dynamic heterogeneity in the supercooled liquid state. We compare {\\xi} 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, {\\xi} from Boson peak measurements above Tg have a different, and unrealistic, temperature dependence.

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

2011-09-01

71

Solute transport in low-heterogeneity sandboxes: The role of correlation length and permeability variance  

NASA Astrophysics Data System (ADS)

work examines how heterogeneity structure, in particular correlation length, controls flow and solute transport. We used two-dimensional (2D) sandboxes (21.9 cm × 20.6 cm) and four modeling approaches, including 2D Advection-Dispersion Equation (ADE) with explicit heterogeneity structure, 1D ADE with average properties, and nonlocal Continuous Time Random Walk (CTRW) and fractional ADE (fADE). The goal is to answer two questions: (1) how and to what extent does correlation length control effective permeability and breakthrough curves (BTC)? (2) Which model can best reproduce data under what conditions? Sandboxes were packed with the same 20% (v/v) fine and 80% (v/v) coarse sands in three patterns that differ in correlation length. The Mixed cases contain uniformly distributed fine and coarse grains. The Four-zone and One-zone cases have four and one square fine zones, respectively. A total of seven experiments were carried out with permeability variance of 0.10 (LC), 0.22 (MC), and 0.43 (HC). Experimental data show that the BTC curves depend strongly on correlation length, especially in the HC cases. The HC One-zone (HCO) case shows distinct breakthrough steps arising from fast advection in the coarse zone, slow advection in the fine zone, and slow diffusion, while the LCO and MCO BTCs do not exhibit such behavior. With explicit representation of heterogeneity structure, 2D ADE reproduces BTCs well in all cases. CTRW reproduces temporal moments with smaller deviation from data than fADE in all cases except HCO, where fADE has the lowest deviation.

Heidari, Peyman; Li, Li

2014-10-01

72

First $?K$ atom lifetime and $?K$ scattering length measurements  

E-print Network

The results of a search for hydrogen-like atoms consisting of $\\pi^{\\mp}K^{\\pm}$ mesons are presented. Evidence for $\\pi K$ atom production by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen in terms of characteristic $\\pi K$ pairs from their breakup in the same target ($178 \\pm 49$) and from Coulomb final state interaction ($653 \\pm 42$). Using these results the analysis yields a first value for the $\\pi K$ atom lifetime of $\\tau=(2.5_{-1.8}^{+3.0})$ fs and a first model-independent measurement of the S-wave isospin-odd $\\pi K$ scattering length $\\left|a_0^-\\right|=\\frac{1}{3}\\left|a_{1/2}-a_{3/2}\\right|= \\left(0.11_{-0.04}^{+0.09} \\right)M_{\\pi}^{-1}$ ($a_I$ for isospin $I$).

B. Adeva; L. Afanasyev; Y. Allkofer; C. Amsler; A. Anania; S. Aogaki; A. Benelli; V. Brekhovskikh; T. Cechak; M. Chiba; P. Chliapnikov; C. Ciocarlan; S. Constantinescu; P. Doskarova; D. Drijard; A. Dudarev; M. Duma; D. Dumitriu; D. Fluerasu; A. Gorin; O. Gorchakov; K. Gritsay; C. Guaraldo; M. Gugiu; M. Hansroul; Z. Hons; S. Horikawa; Y. Iwashita; V. Karpukhin; J. Kluson; M. Kobayashi; V. Kruglov; L. Kruglova; A. Kulikov; E. Kulish; A. Kuptsov; A. Lamberto; A. Lanaro; R. Lednicky; C. Mariñas; J. Martincik; L. Nemenov; M. Nikitin; K. Okada; V. Olchevskii; M. Pentia; A. Penzo; M. Plo; T. Ponta; P. Prusa; G. Rappazzo; A. Romero Vidal; A. Ryazantsev; V. Rykalin; J. Schacher; A. Sidorov; J. Smolik; S. Sugimoto; F. Takeutchi; L. Tauscher; T. Trojek; S. Trusov; T. Urban; T. Vrba; V. Yazkov; Y. Yoshimura; M. Zhabitsky; P. Zrelov

2014-03-04

73

Scaling of Saturated SRS with Laser Intensity, and Intensity Correlation Length  

NASA Astrophysics Data System (ADS)

Recent experiments have indicated that SRS back scatter is produced by non-linearly saturated Langmuir waves. It is essential to the success of ICF to understand how the non-linearly saturated waves and reflectivity respond when driven by RPP-smoothed beams. We have performed experiments in CH filled `gas bag' targets in which the peak envelope intensity of an RPP smoothed f/8 beam is varied from 3× 10^14 W/cm^2 to 2× 10^15 W/cm^2, and find an intensity scaling of the reflectivity that is linear or less than linear at intensities above 6× 10^14 consistent with saturated Langmuir waves. In some cases a much more rapid dependence on intensity is observed at lower intensity, suggesting that the waves are coming out of saturation. In addition to its peak envelope intensity, the RPP-smoothed beam is also characterized by an exponential distribution of intensities with transverse and longitudinal correlation lengths. Numerical simulations show that both correlation lengths depend not only on the beam f number and wavelength, but also on the distance from best focus z and the spot size a, and in fact scale with a parameter ? = (1 + z^2/(f a)^2)^1/2. Experiments to determine the scaling of SRS and SBS with the correlation length will also be discussed. Work performed under the auspices of the U.S. DOE by the LLNL under Contract No. W-7405-ENG-48.

Kirkwood, R. K.; Berger, R. L.; Dixit, S. N.; Rothenberg, J.; Glenzer, S. H.; MacGowan, B. J.; Moody, J. D.; Geddes, C. G. R.

1998-11-01

74

Representative Elementary Length to Measure Soil Mass Attenuation Coefficient  

PubMed Central

With increasing demand for better yield in agricultural areas, soil physical property representative measurements are more and more essential. Nuclear techniques such as computerized tomography (CT) and gamma-ray attenuation (GAT) have been widely employed with this purpose. The soil mass attenuation coefficient (?s) is an important parameter for CT and GAT analysis. When experimentally determined (?es), the use of suitable sized samples enable to evaluate it precisely, as well as to reduce measurement time and costs. This study investigated the representative elementary length (REL) of sandy and clayey soils for ?es measurements. Two radioactive sources were employed (241Am and 137Cs), three collimators (2–4?mm diameters), and 14 thickness (x) samples (2–15?cm). Results indicated ideal thickness intervals of 12–15 and 2–4?cm for the sources 137Cs and 241Am, respectively. The application of such results in representative elementary area (REA) evaluations in clayey soil clods via CT indicated that ?es average values obtained for x?>?4?cm and source 241Am might induce to the use of samples which are not large enough for soil bulk density evaluations (?s). As a consequence, ?s might be under- or overestimated, generating inaccurate conclusions about the physical quality of the soil under study. PMID:24672338

Borges, J. A. R.; Pires, L. F.; Costa, J. C.

2014-01-01

75

Measurement of the Length of an Optical Trap  

NASA Technical Reports Server (NTRS)

NASA Glenn has been involved in developing optical trapping and optical micromanipulation techniques in order to develop a tool that can be used to probe, characterize, and assemble nano and microscale materials to create microscale sensors for harsh flight environments. In order to be able to assemble a sensor or probe candidate sensor material, it is useful to know how far an optical trap can reach; that is, the distance beyond/below the stable trapping point through which an object will be drawn into the optical trap. Typically, to measure the distance over which an optical trap would influence matter in a horizontal (perpendicular to beam propagation) direction, it was common to hold an object in one optical trap, place a second optical trap a known distance away, turn off the first optical trap, and note if the object was moved into the second trap when it was turned on. The disadvantage of this technique is that it only gives information of trap influence distance in horizontal (x y) directions. No information about the distance of the influence of the trap is gained in the direction of propagation of the beam (the z direction). A method was developed to use a time-of-flight technique to determine the length along the propagation direction of an optical trap beam over which an object may be drawn into the optical trap. Test objects (polystyrene microspheres) were held in an optical trap in a water-filled sample chamber and raised to a pre-determined position near the top of the sample chamber. Next, the test objects were released by blocking the optical trap beam. The test objects were allowed to fall through the water for predetermined periods of time, at the end of which the trapping beam was unblocked. It was noted whether or not the test object returned to the optical trap or continued to fall. This determination of the length of an optical trap's influence by this manner assumes that the test object falls through the water in the sample chamber at terminal velocity for the duration of its fall, so that the distance of trap influence can be computed simply by: d = VTt, where d is the trap length (or distance of trap reach), VT is the terminal velocity of the test object, and t is the time interval over which the object is allowed to fall.

Wrbanek, Susan Y.

2010-01-01

76

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. PMID:19896964

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

77

Quantum correlation cost of the weak measurement  

NASA Astrophysics Data System (ADS)

Quantum correlation cost (QCC) characterizing how much quantum correlation is used in a weak-measurement process is presented based on the trace norm. It is shown that the QCC is related to the trace-norm-based quantum discord (TQD) by only a factor that is determined by the strength of the weak measurement, so it only catches partial quantumness of a quantum system compared with the TQD. We also find that the residual quantumness can be 'extracted' not only by the further von Neumann measurement, but also by a sequence of infinitesimal weak measurements. As an example, we demonstrate our outcomes by the Bell-diagonal state.

Zhang, Jun; Wu, Shao-xiong; Yu, Chang-shui

2014-12-01

78

Measurements of Correlation-Enhanced Collision Rates  

NASA Astrophysics Data System (ADS)

We measure the perp-to-parallel collision rate ?| in laser-cooled Magnesium ion plasmas in the strongly-magnetized and correlated regime; and obtain close agreement with the ``Salpeter correlation enhancement'' first studied for fusion in dense plasmas such as stars. The cyclotron energy, like nuclear energy, is released only through rare close-range collisions. These close collisions are suppressed by strong magnetization, because collisional impact distances are rarely as small as a cyclotron radius rc. However, theory predicts that particle correlations reduce this suppression of collisionality, enhancing the rare close collisions by e^?, where ??e^2 / aT is the correlation parameter. We control the plasma temperature over the range 4 0-6 < T < 1eV, giving correlation parameters up to ? 0, with measured collision rates 2 < ?| 2 10^4 sec-1. At low temperatures, the measured ?| are enhanced by up to 10^9 compared to uncorrelated theory, consistent with the predicted correlation enhancement. When the plasma density is reduced from 2 to 0.12 x10^7cm-3, the correlations are eliminated and the measured ?| agree with uncorrelated theory. E.E. Salpeter and H.M. Van Horn, Astrophys. J. 155, 183 (1969). D.H.E. Dubin, Phys. Rev. Lett. 94, 025002 (2005).

Anderegg, F.; Dubin, D. H. E.; O'Neil, T. M.; Driscoll, C. F.

2008-11-01

79

Scale and time dependence of serial correlations in word-length time series of written texts  

NASA Astrophysics Data System (ADS)

This work considered the quantitative analysis of large written texts. To this end, the text was converted into a time series by taking the sequence of word lengths. The detrended fluctuation analysis (DFA) was used for characterizing long-range serial correlations of the time series. To this end, the DFA was implemented within a rolling window framework for estimating the variations of correlations, quantified in terms of the scaling exponent, strength along the text. Also, a filtering derivative was used to compute the dependence of the scaling exponent relative to the scale. The analysis was applied to three famous English-written literary narrations; namely, Alice in Wonderland (by Lewis Carrol), Dracula (by Bram Stoker) and Sense and Sensibility (by Jane Austen). The results showed that high correlations appear for scales of about 50-200 words, suggesting that at these scales the text contains the stronger coherence. The scaling exponent was not constant along the text, showing important variations with apparent cyclical behavior. An interesting coincidence between the scaling exponent variations and changes in narrative units (e.g., chapters) was found. This suggests that the scaling exponent obtained from the DFA is able to detect changes in narration structure as expressed by the usage of words of different lengths.

Rodriguez, E.; Aguilar-Cornejo, M.; Femat, R.; Alvarez-Ramirez, J.

2014-11-01

80

Spin correlation measurements in pseudoscalar meson photoproduction  

Microsoft Academic Search

Because polarized photon beams and polarized proton targets have improved considerably and the techniques for measuring recoil bary on polarizations are continually improving, it is becoming feasible to measure double and triple spin correlations in pseudoscalar meson photoproduction. Of the large number of such experiments possible, only a few will add significantly ne new information to that already obtained from

Gary R. Goldstein; Joseph F. Owens; John P. Rutherfoord; Michael J. Moravcsik

1974-01-01

81

CALIPSO correlative measurements at Napoli EARLINET station  

NASA Astrophysics Data System (ADS)

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite had been launched in April 2006. Its main goal is to probe the vertical structure and to measure the properties of thin clouds and aerosols plume of the Earth's atmosphere. In order to validate the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) products, correlative measurements between CALIPSO and EARLINET stations have been planned in the framework of the validation campaign. At Napoli EARLINET station correlative measurement have been performed starting from the beginning of June 2006. Results obtained both during daytime with elastic lidar and nighttime with Raman lidar operating at two wavelengths (355nm and 532nm) are shown. The results of the application of a new algorithm to retrieve aerosol basckscattering and extinction coefficient backscattering from space and ground based elastic lidar signals are presented. Case study of Saharan dust outbreaks and cirrus clouds captured during correlative measurement runs are discussed.

Wang, Xuan; Armenante, Mario; Frontoso, Grazia; Pisani, Gianluca; Spinelli, N.

2007-10-01

82

Observable measure of bipartite quantum correlations.  

PubMed

We introduce a measure Q of bipartite quantum correlations for arbitrary two-qubit states, expressed as a state-independent function of the density matrix elements. The amount of quantum correlations can be quantified experimentally by measuring the expectation value of a small set of observables on up to four copies of the state, without the need for a full tomography. We extend the measure to 2×d systems, providing its explicit form in terms of observables and applying it to the relevant class of multiqubit states employed in the deterministic quantum computation with one quantum bit model. The number of required measurements to determine Q in our scheme does not increase with d. Our results provide an experimentally friendly framework to estimate quantitatively the degree of general quantum correlations in composite systems. PMID:22587235

Girolami, Davide; Adesso, Gerardo

2012-04-13

83

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

84

EN-011 Ecology January 2002 Measuring the Length of Coarse Woody Debris  

E-print Network

EN-011 Ecology January 2002 Measuring the Length of Coarse Woody Debris By P.L. Marshall and G. Davis KEYWORDS: line intersect sampling, LIS, coarse woody debris, CWD, length, forest ecology, sampling methods CITATION: Marshall, P.L. and G. Davis. 2001. Measuring the Length of Coarse Woody Debris. Research

85

Design and development of deflector cavity for the non- interceptive bunch length measurement system  

NASA Astrophysics Data System (ADS)

A non-interceptive bunch length detector system for the measurement of bunch width of accelerated beam has been designed and developed. This detector system is based on emitted secondary electrons produced by a primary ion beam hitting a thin tungsten wire placed in the beam path.The measurement of the longitudinal beam shape for wide range of beam energy, intensity as well as ion species is possible with this detector. One of the main components of the detector system is a RF deflector cavity used to deflect electrons in correlation with rf phase of the accelerator. The detailed design, development with measurement results of the deflector cavity resonator have been reported in this paper.

Pandey, H. K.; Dechoudhury, S.; Dutta, D. P.; Mandi, T. K.; Bhattacharya, T. K.; Chakrabarti, A.

2014-10-01

86

Correlation of interannual length-of-day variation with El Nino/Southern Oscillation, 1972-1986  

NASA Technical Reports Server (NTRS)

Correlation between interannual length-of-day (LOD) changes and an index representation of El Nino/Southern Oscillation (ENSO) for the period of 1972-1986 was examined in two ways: as the cross-correlation function in the time domain and as the complex coherence spectrum in the frequency domain. The ENSO representation was derived from barometric measurements from the Tahiti and Darwin, Australia, meteorological stations, as the difference of the sea-level pressure between the two locations. The cross correlation between this ENSO representation and LOD variation on the interannual time scale was found to have a maximum value of 0.68 and the LOD phase lag of 2 months, indicating that most of the interannual LOD variation is caused by ENSO, and that the transfer of ENSO's axial angular momentum to the solid earth lags behind the Tahiti-Darwin pressure variation by about 2 months. The corresponding coherence spectrum showed minimum correlation around biennial periods, indicating an influence of the stratospheric quasi-biennial oscillation on LOD variations.

Chao, B. Fong

1988-01-01

87

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

88

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. PMID:23717814

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

2013-01-01

89

Instrument for measuring thin-film belt lengths  

NASA Technical Reports Server (NTRS)

Instrument consists of base, vernier height gauge, sliding block, and balance-beam assembly with tension weight. Pulley bracket is provided with three pulley mounting holes, 4 inches apart, to accommodate widely different belt lengths. Instrument is accurate to within 0.001 inch and is suitable for commercial production.

Casad, T. A.; Piggott, H.; Hoffman, J. K.

1974-01-01

90

New Method for Automatic Body Length Measurement of the Collembolan, Folsomia candida Willem 1902 (Insecta: Collembola)  

PubMed Central

The collembolan, Folsomia candida, is widely used in soil ecotoxicology. In recent years, growth rate of collembolans has become as frequently used endpoint as reproduction rate in ecotoxicological studies. However, measuring collembolan body sizes to estimate growth rate is a complicated and time-consuming task. Here we present a new image analysis method, which facilitates and accelerates the body length measurement of the collembolan Folsomia candida. The new software package, called CollScope, consists of three elements: 1) an imaging device; 2) photographing software; 3) an ImageJ macro for image processing, measurement and data analysis. We give a complete description of the operation of the software, the image analyzing process and describe its accuracy and reliability. The software with a detailed usage manual is attached as Supplementary Material. We report a case study to demonstrate that the automated measurement of collembolan body sizes is highly correlated with the traditional manual measurements (estimated measuring accuracy 0.05 mm). Furthermore, we performed a dose-response ecotoxicity test using cadmium-sulfate by using CollScope as well as classical methods for size measurement. Size data measured by CollScope or manually did not differ significantly. Furthermore the new software package decreased time consumption of the measurements to 42% when tested on 35 animals. Consequently, methodological investigations performed in this study should be regarded as a recommendation for any other routine dose-response study where body growth is an endpoint. PMID:24901322

Bánszegi, Oxána; Kosztolányi, András; Bakonyi, Gábor; Szabó, Borbála; Dombos, Miklós

2014-01-01

91

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

2014-10-01

92

A prospective study of telomere length measured by monochrome multiplex quantitative PCR and risk of non-Hodgkin lymphoma  

PubMed Central

Purpose Telomere length plays an important role in maintaining chromosomal stability and in tumorigenesis. We hypothesized that telomere length in peripheral white blood cell DNA obtained from healthy individuals would be a predictor of future risk of developing non-Hodgkin lymphoma (NHL). Experimental Design Using a new assay to measure relative telomere length, monochrome multiplex quantitative PCR, which strongly correlates with telomere length measured by Southern blot (Spearman r = 0.91, p < 0.0001) and has high precision (coefficient of variation = 7%), we compared telomere length in peripheral white blood cell DNA in 107 incident male NHL cases and 107 matched controls within the prospective Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study cohort. Results Median (10th, 90th percentile) telomere length was 1.10 (0.79, 1.43) in cases and 1.02 (0.78, 1.26) in controls (p = 0.0017, Wilcoxon sign test). There was a strong dose-response relationship between quartiles of telomere length and risk of NHL overall [odds ratios (95% confidence intervals) by quartile: 1.0; 1.1 (0.4-2.7); 1.8 (0.7-4.9); and 3.6 (1.4-8.9); p trend = 0.003)], and this association was similar across the most common NHL subtypes present in this study. Conclusion These results suggest that longer telomere length may be a potential predictor for future risk of NHL. PMID:19934287

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

2009-01-01

93

Length scale dependence and reliability of x-ray strain measurements in metallic glasses  

NASA Astrophysics Data System (ADS)

There is a long history of using x-ray scattering techniques for measuring elastic strain in crystalline materials. Only recently have these techniques been applied to metallic glasses. Results emerging from this work indicate that the elastic strain in metallic glasses varies with the distance from an average atom r in an asymptotic fashion. The reason for such anomalous length-scale behavior of elastic strain in these materials remains unclear. To investigate the origins of this behavior, high energy x-ray scattering experiments were carried out in this work on zirconium and palladium based metallic glass specimens subject to mechanical loading. In both these alloys, the elastic strain obtained from pair correlation function position shifts was found to approach the imposed strain asymptotically. This behavior was found to be independent of the uniaxial compression, uniaxial tension, or pure shear loading geometries. To further investigate the length-scale behavior, molecular dynamics simulations were carried out on a binary Lennard-Jones glass. Elastic strain in this model binary glass, when subject to uniaxial tensile deformation, qualitatively reproduced the length-scale behavior observed in the experiments when the strain was calculated from pair correlation function positions shifts. Other techniques for calculating strain, however, gave different results. Also, independent of the calculation methodology, imposing hydrostatic deformation resulted in nearly length-scale independent strain. These results seem to indicate that the presence of resolved shear stresses and non-affine displacements are central to the length-scale effect. Besides the anomalous length-scale behavior, recent data also suggest that the x-ray technique usually underestimates the elastic strain (with respect to macroscopic value), or overestimates the elastic modulus, in metallic glasses. To investigate this modulus discrepancy, a two-phase model, containing low density liquid-like regions and high density relaxed regions, was investigated. This model was found to be unsuitable because the density difference required to explain the observed discrepancy was too large to be physically meaningful. However, assuming presence of voids, as an extreme of the two phase model, was found to explain the observed discrepancy.

Vempati, Udaya K.

2011-12-01

94

Measuring relative telomere length: Is tissue an issue? Commentary  

E-print Network

Copyright: © Gramatges et al. This is an open?access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited Telomeres, the specialized structures at chromosome ends, consist of long stretches of protein-bound TTAGGG repeats [1]. In certain cell types, such as germ cells and stem cell populations, the length of telomeric DNA is maintained by the enzyme telomerase. Most somatic cells, however, lack sufficient telomerase; consequently, telomeric DNA shortens progressively with each cell division. Upon reaching a critically short length, proliferation is halted and cells often enter a state of senescence. Thus, progressive telomere shortening is thought to serve as a molecular clock for cellular replicative aging. Based upon this fundamental tenet of telomere biology, an everincreasing

Monica M. Gramatges; Alison A. Bertuch

95

Length measurements are fundamen-tal to many aspects of fisheries sci-  

E-print Network

of sampling. In order to identify modes of individual year classes for a length- based assessment116 Length measurements are fundamen- tal to many aspects of fisheries sci- ence. However, there is little formal guidance on the appropriate size of a length sample. Such guidance is of particular

96

A new landscape metric for the identification of terraced sites: The Slope Local Length of Auto-Correlation (SLLAC)  

NASA Astrophysics Data System (ADS)

This work presents the potential for high-resolution remote sensing data (LiDAR digital terrain models) to determine the spatial heterogeneity of terraced landscapes. The study objective is achieved through the identification of a new parameter that distinguishes this unique landscape form from more natural land formations. The morphological indicator proposed is called the Slope Local Length of Auto-Correlation (SLLAC), and it is derived from the local analysis of slope self-similarity. The SLACC is obtained over two steps: (i) calculating the correlation between a slope patch and a defined surrounding area and (ii) identifying the characteristic length of correlation for each neighbourhood. The SLLAC map texture can be measured using a surface metrology metric called the second derivative of peaks, or Spc. For the present study, we tested the algorithm for two types of landscapes: a Mediterranean and an Alpine one. The research method involved an examination of both real LiDAR DTMs and simulated ones, in which it was possible to control terrace shapes and the percentage of area covered by terraces. The results indicate that SLLAC maps exhibit a random aspect for natural surfaces. In contrast, terraced landscapes demonstrate a higher degree of order, and this behaviour is independent of the morphological context and terracing system. The outcomes of this work also prove that Spc values decrease as the area of terraced surfaces increases within the investigated region: the Spc for terraced areas is significantly different from the Spc of a natural landscape. In areas of smooth natural morphology, the Spc identifies terraced areas with a 20% minimum height range covered in terraces. In contrast, in areas of steep morphologies and vertical cliffs, the algorithm performs well when terraces cover at least 50% of the investigated surface. Given the increasing importance of terraced landscapes, the proposed procedure offers a significant and promising tool for the exploration of spatial heterogeneity in terraced sites.

Sofia, Giulia; Marinello, Francesco; Tarolli, Paolo

2014-10-01

97

Nasal bone length throughout gestation: normal ranges based on 3537 fetal ultrasound measurements  

Microsoft Academic Search

Objective To establish normal ranges for nasal bone length measurements throughout gestation and to compare measurements in two subsets of patients of different race (African-American vs. Caucasian) to determine whether a different normal range should be used in these populations. Method Normalnasalbone lengthreferencerangeswere generated using prenatal measurements by a standardized technique in 3537 fetuses. Results The nasal bone lengths were

J. D. Sonek; D. Mckenna; D. Webb; C. Croom; K. Nicolaides

2003-01-01

98

Undamped, length varying TLP pulses measurements and ESD model approximations  

Microsoft Academic Search

Since the introduction of the transmission line pulse -TLP- for the study of electrostatic discharge -ESD- events on integrated circuits -IC-, there has been many approaches on how to compare its tests results with those from other ESD models. Despite it has a very strong correlation with the industry-standard human body model -HBM-, most implementations of TLP weren't suitable for

Gonzalo Andrés Pacheco; Julio Guillermo Zola

2010-01-01

99

Monitoring quantum transport: Backaction and measurement correlations  

NASA Astrophysics Data System (ADS)

We investigate a tunnel contact coupled to a double quantum dot (DQD) and employed as a charge monitor for the latter. We consider both the classical limit and the quantum regime. In the classical case, we derive measurement correlations from conditional probabilities, yielding quantitative statements about the parameter regime in which the detection scheme works well. Moreover, we demonstrate that not only the DQD occupation but also the corresponding current may strongly correlate with the detector current. The quantum-mechanical solution, obtained with a Bloch-Redfield master equation, shows that the backaction of the measurement tends to localize the DQD electrons, and thus significantly reduces the DQD current. Moreover, it provides the effective parameters of the classical treatment. It turns out that already the classical description is adequate for most operating regimes.

Hussein, Robert; Gómez-García, Jorge; Kohler, Sigmund

2014-10-01

100

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

PubMed

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 mum (n = 167 measurements from N = 11 hearts) after correction for tissue orientation, which was significantly greater than that in isolated cells (1.71 mum, n = 346, N = 9 isolations) or ventricular slice preparations (1.79 mum, 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. PMID:20228259

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

2010-05-01

101

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. PMID:20228259

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

2010-01-01

102

Nonsymmetrized correlations in quantum noninvasive measurements.  

PubMed

A long-standing problem in quantum mesoscopic physics is which operator order corresponds to noise expressions like , 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. PMID:23829718

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

2013-06-21

103

ATLAS-3 correlative measurement opportunities with UARS and surface observations  

NASA Technical Reports Server (NTRS)

The third ATmospheric Laboratory for Applications and Science (ATLAS-3) mission was flown aboard the Space Shuttle launched on November 3, 1994. The mission length was approximately 10 days and 22 hours. The ATLAS-3 Earth-viewing instruments provided a large number of measurements which were nearly coincident with observations from experiments on the Upper Atmosphere Research Satellite (UARS). Based on ATLAS-3 instrument operating schedules, simulations were performed to determine when and where correlative measurements occurred between ATLAS and UARS instruments, and between ATLAS and surface observations. Results of these orbital and instrument simulations provide valuable information for scientists to compare measurements between various instruments on the two satellites and at selected surface sites.

Harrison, Edwin F.; Denn, Fred M.; Gibson, Gary G.

1995-01-01

104

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

105

Young Children's Understandings of Length Measurement: Evaluating a Learning Trajectory  

ERIC Educational Resources Information Center

This study investigated the development of length measurement ideas in students from prekindergarten through 2nd grade. The main purpose was to evaluate and elaborate the developmental progression, or levels of thinking, of a hypothesized learning trajectory for length measurement to ensure that the sequence of levels of thinking is consistent…

Szilagyi, Janka; Clements, Douglas H.; Sarama, Julie

2013-01-01

106

Eddy correlation measurements of submarine groundwater discharge  

USGS Publications Warehouse

This paper presents a new, non-invasive means of quantifying groundwater discharge into marine waters using an eddy correlation approach. The method takes advantage of the fact that, in virtually all aquatic environments, the dominant mode of vertical transport near the sediment-water interface is turbulent mixing. The technique thus relies on measuring simultaneously the fluctuating vertical velocity using an acoustic Doppler velocimeter and the fluctuating salinity and/or temperature using rapid-response conductivity and/or temperature sensors. The measurements are typically done at a height of 5-15??cm above the sediment surface, at a frequency of 16 to 64??Hz, and for a period of 15 to 60??min. If the groundwater salinity and/or temperature differ from that of the water column, the groundwater specific discharge (cm d- 1) can be quantified from either a heat or salt balance. Groundwater discharge was estimated with this new approach in Salt Pond, a small estuary on Cape Cod (MA, USA). Estimates agreed well with previous estimates of discharge measured using seepage meters and 222Rn as a tracer. The eddy correlation technique has several desirable characteristics: 1) discharge is quantified under in-situ hydrodynamic conditions; 2) salinity and temperature can serve as two semi-independent tracers of discharge; 3) discharge can be quantified at high temporal resolution, and 4) long-term records of discharge may be possible, due to the low power requirements of the instrumentation. ?? 2007 Elsevier B.V. All rights reserved.

Crusius, J.; Berg, P.; Koopmans, D.J.; Erban, L.

2008-01-01

107

Bose-Einstein correlation measurements at CMS  

NASA Astrophysics Data System (ADS)

Multidimensional and one-dimensional quantum-statistical (Bose-Einstein) correlations are measured in proton-proton collisions at 0.9, 2.76 and 7 TeV, in proton-lead collisions at 5.02 TeV/nucleon pair and peripheral lead-lead collisions at 2.76 TeV/nucleon pair center-of-mass energy with the CMS detector at the LHC. The correlation functions are extracted in terms of different components of the relative momentum of the pair, in order to investigate the extension of the emission source in different directions. The results are presented for different intervals of transverse pair momentum, kT, and charged particle multiplicity of the collision, Ntracks, as well as for their integrated values. Besides inclusive charged particles, charged pions and kaons, identified via their energy loss in the silicon tracker detector, can also be correlated. The extracted source radii increase with increasing multiplicity, and decrease with increasing kT. The results open the possibility to study scaling and factorization properties of these radii as a function of multiplicity, kT, colliding system size and center-of-mass energy.

Dogra, Sunil Manohar

2014-11-01

108

Focal length measurement based on the wavefront difference method by a Fizeau interferometer.  

PubMed

A method for measuring the focal length of the lens by a Fizeau interferometer is proposed. Based on the Gaussian imaging equation and the longitudinal displacements of the object point and image point, a precise formula for focal length calculation is deduced. The longitudinal displacement of the object points is determined by the wavefront difference method with a subnanometer resolution. An experimental system for focal length measurements is set up to verify the principle. The sources of uncertainty in measurement are discussed. Both the positive and negative lens experimental results indicate that the measurement accuracy is less than 0.16% under normal experimental environment. PMID:25321352

Yang, Zhongming; Gao, Zhishan; Dou, Jiantai; Wang, Xinxing

2014-09-01

109

A Preliminary Test of Measurement of Joint Angles and Stride Length with Wireless Inertial Sensors for Wearable Gait Evaluation System  

PubMed Central

The purpose of this study is to develop wearable sensor system for gait evaluation using gyroscopes and accelerometers for application to rehabilitation, healthcare and so on. In this paper, simultaneous measurement of joint angles of lower limbs and stride length was tested with a prototype of wearable sensor system. The system measured the joint angles using the Kalman filter. Signals from the sensor attached on the foot were used in the stride length estimation detecting foot movement automatically. Joint angles of the lower limbs were measured with stable and reasonable accuracy compared to those values measured with optical motion measurement system with healthy subjects. It was expected that the stride length measurement with the wearable sensor system would be practical by realizing more stable measurement accuracy. Sensor attachment position was suggested not to affect significantly measurement of slow and normal speed movements in a test with the rigid body model. Joint angle patterns measured in 10?m walking with a healthy subject were similar to common patterns. High correlation between joint angles at some characteristic points and stride velocity were also found adequately. These results suggested that the wireless wearable inertial sensor system could detect characteristics of gait. PMID:21941531

Watanabe, Takashi; Saito, Hiroki; Koike, Eri; Nitta, Kazuki

2011-01-01

110

Establishment of a Method to Measure Length of the Ulnar Nerve and Standardize F-wave Values in Clinically Normal Beagles  

PubMed Central

We designed a new method of measuring the length of the ulnar nerve and determining standard values for F-wave parameters of the ulnar nerve in clinically normal beagles. Nerve length must be precisely measured to determine F-wave latency and conduction velocity. The length of the forelimb has served as the length of the ulnar nerve for F-wave assessments, but report indicates that F-wave latency is proportional to the length of the pathway traveled by nerve impulses. Therefore, we measured the surface distance from a stimulus point to the spinous process of the first thoracic vertebra (nerve length 1) and the anterior horn of the scapula (nerve length 2) as landmarks through the olecranon and the shoulder blade acromion. The correlation coefficients between the shortest F-wave latency and the length of nerves 1, 2 or the forelimb were 0.61, 0.7 and 0.58. Nerve length 2 generated the highest value. Furthermore, the anterior horn of the scapula was easily palpated in any dog regardless of well-fed body. We concluded that nerve length 2 was optimal for measuring the length of the ulnar nerve. PMID:25649942

HIRASAWA, Shun; SHIMIZU, Miki; MARUI, Yuumi; KISHIMOTO, Miori; OKUNO, Seiichi

2014-01-01

111

Subpicometer Length Measurement Using Semiconductor Laser Tracking Frequency Gauge  

NASA Technical Reports Server (NTRS)

We have demonstrated heretofore unattained distance precision of 0:14pm (2pm) incremental and 14nm (2.9 micrometers) absolute in a resonant (nonresonant) interferometer at an averaging time of 1 s, using inexpensive telecommunications diode lasers. We have controlled the main source of error, that due to spurious reflection and the resulting amplitude modulation. In the resonant interferometer, absolute distance precision is well under lambda/6. Therefore, after an interruption, an absolute distance measurement can be used to return to the same interferometer order.

Thapa, Rajesh; Phillips, James D.; Rocco, Emanuele; Reasenburg, Robert D.

2011-01-01

112

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

113

Study on Continuous-Casting Slab High-Precision Length Measurement and Cutting Control Technique  

Microsoft Academic Search

Directed at the precision-decreasing problems like abrasion and slippage which occur in the roller for measuring continuous-casting slab length, a technology of edge detection for CCD (charge coupled device) digital image was adopted that fulfilled fixed-length cutting control at the first stage and dynamic tracing of casting speed. With hydraulic pressure cushioning and back-pushing technology, the second stage high-precision fixed-length

Huiyi Zhang; Tao Tao; Xingli Jiao

2006-01-01

114

High-resolution measurement of fiber length by using a mode-locked fiber laser configuration  

Microsoft Academic Search

A simple method to precisely measure fiber length has been experimentally demonstrated by using a mode-locked fiber laser configuration. Since the transit time in a cavity is exactly proportional to the cavity length, it is easy to obtain the fiber length from the generation of mode-locked pulses in the fiber laser with a long-range nonlinear optical loop mirror that includes

Y. L. Hu; L. Zhan; Z. X. Zhang; S. Y. Luo; Y. X. Xia

2007-01-01

115

Diffusion length measurements using the scanning electron microscope. [in semiconductor devices  

NASA Technical Reports Server (NTRS)

A measurement technique employing the scanning electron microscope is described in which values of the true bulk diffusion length are obtained. It is shown that surface recombination effects can be eliminated through the application of highly doped surface field layers. The influence of high injection level effects and low-high junction current generation on the resulting measurement was investigated. Close agreement is found between the diffusion lengths measured by this method and those obtained using a penetrating radiation technique.

Weizer, V. G.

1975-01-01

116

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

117

Correlation measurements of fission-fragment properties  

NASA Astrophysics Data System (ADS)

For the development of future nuclear fission applications and for a responsible handling of nuclear waste the a-priori assessment of the fission-fragments' heat production and toxicity is a fundamental necessity. The success of an indispensable modelling of the fission process strongly depends on a good understanding of the particular mechanism of scission, the mass fragmentation and partition of excitation energy. Experimental observables are fission-fragment properties like mass- and energy-distributions, and the prompt neutron as well as ?-ray multiplicities and emission spectra. The latter quantities should preferably be known as a function of fragment mass and excitation energy. Those data are highly demanded as published by the OECD-NEA in its high priority data request list. With the construction of the double (v, E) spectrometer VERDI we aim at measuring pre- and post-neutron masses directly and simultaneously to avoid prompt neutron corrections. From the simultaneous measurement of pre- and post-neutron fission-fragment data the prompt neutron multiplicity may then be inferred fully correlated with fragment mass yield and total kinetic energy. Using an ultra-fast fission event trigger spectral prompt fission ?-ray measurements may be performed. For that purpose recently developed lanthanum-halide detectors, with excellent timing characteristics, were coupled to the VERDI spectrometer allowing for a very good discrimination of fission ?-rays and prompt neutrons due to their different time-of-flight.

Oberstedt, S.; Belgya, T.; Billnert, R.; Borcea, R.; Cano-Ott, D.; Göök, A.; Hambsch, F.-J.; Karlsson, J.; Kis, Z.; Martinez, T.; Oberstedt, A.; Szentmiklosi, L.; Takác, K.

2010-10-01

118

Modeling the Length Effect: Specifying the Relation with Visual and Phonological Correlates of Reading  

ERIC Educational Resources Information Center

Beginning readers' reading latencies increase as words become longer. This length effect is believed to be a marker of a serial reading process. We examined the effects of visual and phonological skills on the length effect. Participants were 184 second-grade children who read 3- to 5-letter words and nonwords. Results indicated that reading…

van den Boer, Madelon; de Jong, Peter F.; Haentjens-van Meeteren, Marleen M.

2013-01-01

119

Direct measurement of the plasma screening length and surface potential near the lunar terminator  

NASA Technical Reports Server (NTRS)

Direct measurement of the lunar dayside surface potential and screening length has been made by the suprathermal ion detector experiment (Side) near the terminator. In a region 20-30 deg from the terminator at the Apollo 14 and 15 sites the surface potential is found to be approximately 50 V negative, and the screening length to be about 1 km. This value of the screening length is more than 2 orders of magnitude greater than the solar wind 'Debye' length. The strong negative surface potential in this region may be due to enhanced temperature and density of the solar wind plasma.

Benson, J.

1977-01-01

120

COMBINATION OF CORRELATION MEASURES FOR DENSE STEREO MATCHING  

E-print Network

COMBINATION OF CORRELATION MEASURES FOR DENSE STEREO MATCHING Sylvie CHAMBON Institut Franc¸ais des of dense stereo matching of pixels, we study the combination of different correlation mea- sures of stereo-matching by combining complementary correlation measures and it also highlights the two measures

Paris-Sud XI, Université de

121

[Shushu (ancient Chinese numerology) in Lingshu: Gudu (Miraculous Pivot: Bone-Length Measurement)].  

PubMed

Lingshu: Gudu (Miraculous Pivot: Bone-Length Measurement) is compared with literatures concerning the Shushu (ancient Chinese numerology) of the Qin Dynasty (221 B. C. - 206 B. C. ) and the Han Dynasty (206 B. C.-220 A. D.) in this article. And it is discovered that "the number of heaven and earth" in Yijing (The Book of Change) was implied in the bone-length measurement. The theory of Shushu is hidden in the sized of head, neck, chest, abdomen, back and 4 extremities according to the measurement. The meaning of establishment of bone-length measurement, which is found to have universality, laid in setting down the measurement of meridians. And it is the origin of the proportional measurement of locating acupoints. Checked with the theory of Shushu, errors in the description of bone-length measurement could also be found in Lingshu: Gudu (Miraculous Pivot: Bone-Length Measurement) of the present edition, which is helpful for the modern study on the measurement. PMID:21058490

Zhuo, Lian-Shi

2010-10-01

122

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

123

Polarization gating enables sarcomere length measurements by laser diffraction in fibrotic muscle  

NASA Astrophysics Data System (ADS)

Sarcomere length is a key parameter commonly measured in muscle physiology since it dictates striated muscle active force. Laser diffraction (LD)-based measurements of sarcomere length are time-efficient and sample a greater number of sarcomeres compared with traditional microscopy-based techniques. However, a limitation to LD techniques is that signal quality is severely degraded by scattering events as photons propagate through tissue. Consequently, sarcomere length measurements are unattainable when the number of scattering events is sufficiently large in muscle tissue with a high scattering probability. This occurs in fibrotic skeletal muscle seen in muscular dystrophies and secondary to tissue trauma, thus eliminating the use of LD to study these skeletal muscle ailments. Here, we utilize polarization gating to extract diffracted signals that are buried in noise created by scattering. Importantly, we demonstrate that polarization-gated laser diffraction (PGLD) enables sarcomere length measurements in muscles from chronically immobilized mice hind limbs; these muscles have a substantial increase of intramuscular connective tissue that scatter light and disable sarcomere length measurements by traditional LD. Further, we compare PGLD sarcomere lengths to those measured by bright field (BF) and confocal microscopy as positive controls and reveal a significant bias of BF but not of confocal microscopy.

Young, Kevin W.; Dayanidhi, Sudarshan; Lieber, Richard L.

2014-11-01

124

A Class of Repeated Measures Concordance Correlation Coefficients  

Microsoft Academic Search

The repeated measures concordance correlation coefficient was proposed for measuring agreement between two raters or two methods of measuring a response in the presence of repeated measurements (King et al., 2007). This paper proposes a class of repeated measures concordance correlation coefficients that are appropriate for both continuous and categorical data. We illustrate the methodology with examples comparing (1) 1-hour

Tonya S. King; Vernon M. Chinchilli; Kai-Ling Wang; Josep L. Carrasco

2007-01-01

125

Prospective Secondary Mathematics Teachers' Pedagogical Knowledge for Teaching the Estimation of Length Measurements  

ERIC Educational Resources Information Center

Prospective secondary mathematics teachers' pedagogical knowledge for teaching the estimation of length measurements was investigated by examining their personal benchmarks for measurement estimation. Benchmarks for measurement estimation are the meaningful representations of units that serve to increase one's understanding of…

Subramaniam, Karthigeyan

2014-01-01

126

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

127

Length measurement of the eye using a swept-source interferometer.  

PubMed

In this article, a swept-source setup based on a semiconductor optical amplifier at the central wavelength of 1050 nm for measurements of the axial length inside the eye is presented. The large coherence length is achieved using a tunable optical filter, consisting of a reflective diffraction grating, two Littrow prisms, and a scanner. It was possible to achieve a coherence length of 40 mm, which allowed interference measurements in this range to be made. Measurements of the biomedical data of a human model eye are presented. To realize faster measurements, the data acquisition must be increased to more than 2 MS/s. In further studies, the usage of a field-programmable gate array, to achieve faster measurements, will be considered. PMID:24096435

Al-Mohamedi, Haroun; Prinz, Andreas; Mieskes, Guido; Oltrup, Theo; Bende, Thomas

2014-02-01

128

The Commissioning Of A Three Dimensional Depolarized Neutron Beamline For Studying The Magnetic Correlation Length Of A Magnetic Material At Tsing Hua Open-Pool Reactor  

SciTech Connect

A new three dimensional neutron depolarization beamline was commissioning at W3 beam port of Tsing Hua Open Pool Reactor (THOR, 2 MW) located in Hsinchu, Taiwan. The beamline consists of a pair of Heusler crystals as neutron polarizer and analyzer. Two three-dimensional rotators were placed before and after the sample position. The sample chamber was enclosed in a mu-metal enclosure with a gradient field at incident and exit ports. Typically, 0.237 nm of monoenergetic neutron was selected for experiments. A flipping ratio of 23 can be obtained which corresponds to a polarization ratio of 92% of this beamline. The typical intensity is 400 n/cm{sup 2}s at 1 MW operation. Magnetic correlation lengths of Ni-ferrite powders with different packing densities were measured to understand the characteristics of this beamline. The magnetic correlation lengths were observed to be 2 mum at virgin state and about 3.1 mum at remanent state. This magnetic correlation length in the virgin state is similar than the particle size. No significant change of domain size at packing density up to 60% implies that the domain wall motion is hindered by the porosity of the sample.

Su, H.-C.; Chang, H.-H.; Hu, C.-W. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan 30013 (China); Lee, C.-H.; Wu, Y.-H. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan 30013 (China); Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu, Taiwan 30013 (China); Chang, L. J. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu, Taiwan 30013 (China); Ioffe, A. [Juelich Centre for Neutron Science (JCNS) Forschungszentrum Juelich Outstation at FRM-II, Lichtenbergstrasse 1, D-85747 Garching (Germany); Kraan, H. T. [Delft University of Technology, Delft (Netherlands)

2010-01-05

129

Tyre contact length on dry and wet road surfaces measured by three-axial accelerometer  

NASA Astrophysics Data System (ADS)

We determined the tyre contact length on dry and wet roads by measuring the accelerations of the inner liner with a three-axial accelerometer. The influence of the tyre pressure, driving velocity, and tread depth on the contact length was studied in both types of road surface conditions. On dry asphalt the contact length was almost constant, regardless of the driving velocity. On wet asphalt the presence of water could be detected even at low driving velocities (e.g. 20 km/h for a worn tyre) as the contact length began to decrease from that found in the dry asphalt situation. In addition to improving the performance of active safety systems and driver warning systems, the contact length information could be beneficial for classifying and studying the aquaplaning behaviour of tyres.

Matilainen, Mika; Tuononen, Ari

2015-02-01

130

Apparent correlations between the static length of relaxation and the linear size of dynamic heterogeneity in fragile liquids  

Microsoft Academic Search

.  The most puzzling aspect of the glass transition observed in\\u000a laboratory is the decoupling of the dynamics from the structure.\\u000a As an attempt to reconcile the dynamic and the static lengthscales\\u000a associated with the glass problem, we discuss the apparent\\u000a correlations between the static relaxation length, defined as that\\u000a lengthscale over which the potential energy fluctuation is\\u000a correlated, with the

S. Davatolhagh

2007-01-01

131

Study on growing correlation length prior to the earthquakes occurred in Gansu Province and its nearby area  

Microsoft Academic Search

The growing correlation length prior to the moderate-great earthquakes occurred in Gansu Province and its nearby area since\\u000a 1986 has been studied using the method of single-link cluster analysis (SLC). According to different conditions in the source\\u000a area, the circular spatial window centered in the epicenter and the parallelgrammic spatial window along the fault belt have\\u000a been selected. The results

Dai-Lu Rong; Ya-Rong Li; Xu-Zhou Liu

2004-01-01

132

Absolute qPCR for Measuring Telomere Length in Bone Marrow Samples of Plasma Cell Disorders.  

PubMed

Telomere length (TL) is currently used as an emerging biomarker in understanding the development/progression of hematological malignancies. The absolute quantitative PCR (qPCR) methodology has allowed the study of TL from a variety of mammalian tissues, but it has not been tested for bone marrow (BM) samples. In this study, we have examined the relationship between TL data generated by absolute qPCR versus those obtained by terminal restriction fragments (TRF) in 102 BM samples from patients with plasma cell disorders. A significant linear correlation between both methodologies was observed (p < 0.0001; r (2) = 0.70). Results were also analyzed in relation to clinical characteristics and significant associations between telomere shortening and parameters of adverse prognosis were observed. Furthermore, another set of 47 BM samples from patients with low quantity of DNA for TRF assay were suitably analyzed by qPCR, indicating the usefulness of the absolute qPCR methodology for the inclusion of patients with scarce material to the study. Taken together, these findings are of interest considering the importance of telomere dysfunction in the pathogenesis of cancer and give a new alternative to measure TL in hematologic disorders with substantial time and cost savings. PMID:25311116

Panero, Julieta; O'Callaghan, Nathan J; Fenech, Michael; Slavutsky, Irma

2015-02-01

133

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

134

Technique for the focal-length measurement of positive lenses using Fizeau interferometry  

SciTech Connect

We present what we believe is a new technique for the focal-length measurement of positive lenses using Fizeau interferometery. The technique utilizes the Gaussian lens equation. The image distance is measured interferometrically in terms of the radius of curvature of the image-forming wavefront emerging from the lens. The radii of curvature of the image-forming wavefronts corresponding to two different axial object positions of known separation are measured. The focal length of the lens is determined by solving the equations obtained using the Gaussian lens equation for the two object positions. Results obtained for a corrected doublet lens of a nominal focal length of 200.0 mm with a measurement uncertainty of {+-}2.5% is presented.

Pavan Kumar, Yeddanapudi; Chatterjee, Sanjib

2009-02-01

135

Technique for the focal-length measurement of positive lenses using Fizeau interferometry.  

PubMed

We present what we believe is a new technique for the focal-length measurement of positive lenses using Fizeau interferometery. The technique utilizes the Gaussian lens equation. The image distance is measured interferometrically in terms of the radius of curvature of the image-forming wavefront emerging from the lens. The radii of curvature of the image-forming wavefronts corresponding to two different axial object positions of known separation are measured. The focal length of the lens is determined by solving the equations obtained using the Gaussian lens equation for the two object positions. Results obtained for a corrected doublet lens of a nominal focal length of 200.0 mm with a measurement uncertainty of +/-2.5% is presented. PMID:19183601

Kumar, Yeddanapudi Pavan; Chatterjee, Sanjib

2009-02-01

136

In-service fiber line identification based on high-resolution fiber length measurement  

Microsoft Academic Search

An in-service fiber line identification scheme based on high-resolution fiber line length measurement is proposed and demonstrated for single star, survivable, and passive double star architectures to meet the demands of in-service cable reconstruction. In the proposed scheme, a reference fiber is assigned just after the fiber network has been constructed and differences in length between the constructed fiber lines

Yutaka Katsuyama

1995-01-01

137

Can we measure structures to a precision better than the Planck length?  

E-print Network

It was recently claimed that the Planck length is not a limit to the precision by which we can measure distances, but that instead it is merely the Planck volume that limits the precision by which we can measure volumes. Here, we investigate this claim and show that the argument does not support the conclusion.

Sabine Hossenfelder

2012-05-16

138

Possible methods of measuring the length of sub-picosecond electron bunches in the frequency domain  

SciTech Connect

The traditional method of measuring extremely short electron beams using streak cameras begins to become problematic and expensive at bunch lengths at a picosecond and below. In this paper a few alternatives, based on the differential measurement of the Fourier spectrum of the longitudinal charge distribution of a bunch are suggested and evaluated.

Jackson, G.P.

1992-12-01

139

Connection between measurement disturbance relation and multipartite quantum correlation  

NASA Astrophysics Data System (ADS)

It is found that the measurement disturbance relation (MDR) determines the strength of quantum correlation and hence is one of the essential facets of the nature of quantum nonlocality. In reverse, the exact form of MDR may be ascertained through measuring the correlation function. To this aim, an optical experimental scheme is proposed. Moreover, by virtue of the correlation function, we find that the quantum entanglement, the quantum nonlocality, and the uncertainty principle can be explicitly correlated.

Li, Jun-Li; Du, Kun; Qiao, Cong-Feng

2015-01-01

140

PEGylated cyclodextrins as novel siRNA nanosystems: correlations between polyethylene glycol length and nanoparticle stability.  

PubMed

Silencing disease-related genes in the central nervous system (CNS) using short interfering RNA (siRNA) holds great promise for treating neurological disorders. Yet, delivery of RNAi therapeutics to the brain poses major challenges to non-viral systems, especially when considering systemic administration. Cationic nanoparticles have been widely investigated for siRNA delivery, but the tendency of these to aggregate in physiological environments limits their intravenous application. Thus, strategies to increase the stability of nanoparticles have been developed. Here, we investigated the ability of modified cationic amphiphilic or PEGylated amphiphilic cyclodextrins (CD) to formulate stable CD.siRNA nanoparticles. To this end, we describe a simple method for post-modification of pre-formed cationic CD.siRNA nanoparticles at their surface using PEGylated CDs of different PEG lengths. PEGylated CD.siRNA nanoparticles presented reduced surface charges and increased stability in physiological salt conditions. Stability of PEGylated CD.siRNA nanoparticles in vitro increased with both PEG length and PEG density at the surface. Furthermore, in a comparative pharmacokinetic study, increased systemic exposure and reduced clearance were achieved with CD-formulations when compared to naked siRNAs. However, no significant differences were observed among non-PEGylated and PEGylated CD.siRNAs suggesting that longer PEG lengths might be required for improving stability in vivo. PMID:24992319

Godinho, Bruno M D C; Ogier, Julien R; Quinlan, Aoife; Darcy, Raphael; Griffin, Brendan T; Cryan, John F; O'Driscoll, Caitriona M

2014-10-01

141

Correlation between 29Si NMR chemical shifts and mean Si?O bond lengths for calcium silicates  

NASA Astrophysics Data System (ADS)

The nine resonances in the hitherto unassigned 29Si magic-angle-spinning NMR spectrum of tricalcium silicate (C 3S) are tentatively assigned using a ? versus overlinedSi?O correlation between isotropic 29Si chemical shifts (?) and mean Si?O bond lengths ( overlinedSi?O) observed for the a' L-, ?-, and ?-dicalcium silicate (C 2S) polymorphs. This results in a linear correlation, ?(ppm) = - 316.7 overlinedSi?O(Å) + 445.3 ( R = -0.975, 12 data points), with increasing shielding corresponding to longer overlinedSi?O bond distance in calcium monosilicates (Q o). The results and earlier established ? versus overlinedSi?O correlations are discussed in relation to recent ab initio calculations of 29Si chemical shifts in isolated SiO 4-4 tetrahedra.

Skibsted, Jørgen; Hjorth, Jens; Jakobsen, Hans J.

1990-09-01

142

A NONLOCAL STRAIN MEASURE FOR DIGITAL IMAGE CORRELATION  

E-print Network

A NONLOCAL STRAIN MEASURE FOR DIGITAL IMAGE CORRELATION R. B. LEHOUCQ, P. L. REU, AND D. Z. TURNER Abstract. We propose a nonlocal strain measure for use with digital image correlation (DIC). Whereas numerical examples, the potential of this new strain measure for problems with steep gradients. We also show

Lehoucq, Rich

143

Correlating DSC and X-Ray Measurements Of Crystallinity  

NASA Technical Reports Server (NTRS)

Experiment demonstrated approximate linear correlation between degree of crystallinity of multiphase polymer (as calculated from x-ray diffraction measurements) and heat of fusion of polymer (as calculated from differential scanning calorimetry (DSC) measurements). Correlation basis of simple new technique for estimating degree of crystallinity of specimens of polymer from DSC measurements alone.

Yen, Shiao-Ping S.; Lowry, Lynn E.; Bankston, Clyde P.

1991-01-01

144

Computer-assisted measurement of cervical length from transvaginal ultrasound images  

NASA Astrophysics Data System (ADS)

We describe an image processing algorithm that identifies the anatomic landmarks of the cervix on a transvaginal ultrasound image and determines the standard cervical length. The system is composed of four stages: The first stage is adaptive speckle suppression using variable length sticks algorithm. The second stage is the location of the internal cervical opening or 'os' using a region-based segmentation. The third stage is delineation of the cervical canal. The fourth stage uses gray level summation patterns and prior knowledge to first localize the tissue boundary of the external cervix. A template is then used to determine the specific location of the external os. The cervical length is determined and calculated to image scale. For validation, 101 cervical ultrasound images were selected from a series of 37 examinations performed on 17 patients over an 8-month period. Repeated measurements of cervical length using the computer assisted method were compared with those of two experienced sonographers. The mean coefficient of variation for serial measurements was 1.1% for the computer assisted method and averaged 4.7% for the manual method. In a pairwise comparison, the mean cervical length for the computer method was not different from the mean manual cervical length.

Wu, Min; Fraser, Robert F.; Chen, Chang W.

2002-05-01

145

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

SciTech Connect

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 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 [1]. 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.

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

2006-05-01

146

Interpretation of scanning electron microscope measurements of minority carrier diffusion lengths in semiconductors  

NASA Technical Reports Server (NTRS)

In scanning electron microscope (SEM) injection measurements of minority carrier diffusion lengths some uncertainties of interpretation exist when the response current is nonlinear with distance. This is significant in epitaxial layers where the layer thickness is not large in relation to the diffusion length, and where there are large surface recombination velocities on the incident and contact surfaces. An image method of analysis is presented for such specimens. A method of using the results to correct the observed response in a simple convenient way is presented. The technique is illustrated with reference to measurements in epitaxial layers of GaAs. Average beam penetration depth may also be estimated from the curve shape.

Flat, A.; Milnes, A. G.

1978-01-01

147

Measuring telomere length for the early detection of precursor lesions of esophageal squamous cell carcinoma  

PubMed Central

Background Esophageal cancer is the sixth leading cause of cancer death worldwide; current early detection screening tests are inadequate. Esophageal balloon cytology successfully retrieves exfoliated and scraped superficial esophageal epithelial cells, but cytologic reading of these cells has poor sensitivity and specificity for detecting esophageal squamous dysplasia (ESD), the precursor lesion of esophageal squamous cell carcinoma (ESCC). Measuring telomere length, a marker for chromosomal instability, may improve the utility of balloon cytology for detecting ESD and early ESCC. Methods We examined balloon cytology specimens from 89 asymptomatic cases of ESD (37 low-grade and 52 high-grade) and 92 age- and sex-matched normal controls from an esophageal cancer early detection screening study. All subjects also underwent endoscopy and biopsy, and ESD was diagnosed histopathologically. DNA was extracted from the balloon cytology cells, and telomere length was measured by quantitative PCR. A receiver operating characteristic (ROC) curve was plotted for telomere length as a diagnostic marker for high-grade dysplasia. Results Telomere lengths were comparable among the low- and high-grade dysplasia cases and controls, with means of 0.96, 0.96, and 0.92, respectively. The area under the ROC curve was 0.55 for telomere length as a diagnostic marker for high-grade dysplasia. Further adjustment for subject characteristics, including sex, age, smoking, drinking, hypertension, and body mass index did not improve the use of telomere length as a marker for ESD. Conclusions Telomere length of esophageal balloon cytology cells was not associated with ESCC precursor lesions. Therefore, telomere length shows little promise as an early detection marker for ESCC in esophageal balloon samples. PMID:24308314

2013-01-01

148

Summative Evaluation of the Measurement of Length Unit of the Money, Measurement and Time Program. Research Report No. 71.  

ERIC Educational Resources Information Center

Field testing of the Length Unit of the Money, Measurement and Time Program was conducted with 23 elementary school classes of educable mentally handicapped (EMH) children. The 218 Ss were assigned to the experimental group, the Hawthorne group, or the control group. Two criterion referenced tests were administered to evaluate Ss' measuring skills…

Krus, Patricia H.; And Others

149

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

PubMed Central

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

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

2014-01-01

150

Cumulative Measure of Correlation for Multipartite Quantum States  

NASA Astrophysics Data System (ADS)

The present article proposes a measure of correlation for multiqubit mixed states. The measure is defined recursively, accumulating the correlation of the subspaces, making it simple to calculate without the use of regression. Unlike usual measures, the proposed measure is continuous additive and reflects the dimensionality of the state space, allowing to compare states with different dimensions. Examples show that the measure can signal critical points (CPs) in the analysis of Quantum Phase Transitions (QPTs) in Heisenberg models.

de Oliveira, André L. Fonseca; Buksman, Efrain; de Lacalle, Jesús García López

2014-01-01

151

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

152

Path-length measurement performance evaluation of polarizing laser interferometer prototype  

NASA Astrophysics Data System (ADS)

The space laser interferometer has been considered the most promising means for detecting gravitational waves and improving the accuracy and spatial resolution of the Earth's gravity model. An on-ground polarizing laser interferometer prototype equipped with one reference interferometer and two measurement interferometers having equal-length arms is presented in the paper. The laser interferometer prototype is designed as the demonstration of a Chinese space laser interferometer antenna in the future, of which the path-length measurement performance evaluation and preliminary noise analysis are investigated here. The results show that the path-length measurement sensitivity is better than 200 pm/Hz½ in the frequency band of 10 mHz-1 Hz, and the sensitivity of measuring the motion of a sinusoidally driven testmass is better than 100 pm within the frequency regime of 1 mHz-1 Hz. In this way, laboratory activities have demonstrated the feasibility of this prototype to measure tiny path-length fluctuations of the simulated testmass. As a next step, adopting an integrated design of optics and optical substrate to enhance the stability of the laser interferometer is being planned, and other key techniques included in the space laser interferometer such as laser pointing modulation and laser phase-locking control are to be implanted into this prototype are under consideration.

Li, Yu-qiong; Luo, Zi-ren; Liu, He-shan; Dong, Yu-hui; Jin, Gang

2015-02-01

153

Path-length measurement performance evaluation of polarizing laser interferometer prototype  

NASA Astrophysics Data System (ADS)

The space laser interferometer has been considered the most promising means for detecting gravitational waves and improving the accuracy and spatial resolution of the Earth's gravity model. An on-ground polarizing laser interferometer prototype equipped with one reference interferometer and two measurement interferometers having equal-length arms is presented in the paper. The laser interferometer prototype is designed as the demonstration of a Chinese space laser interferometer antenna in the future, of which the path-length measurement performance evaluation and preliminary noise analysis are investigated here. The results show that the path-length measurement sensitivity is better than 200 pm/Hz½ in the frequency band of 10 mHz-1 Hz, and the sensitivity of measuring the motion of a sinusoidally driven testmass is better than 100 pm within the frequency regime of 1 mHz-1 Hz. In this way, laboratory activities have demonstrated the feasibility of this prototype to measure tiny path-length fluctuations of the simulated testmass. As a next step, adopting an integrated design of optics and optical substrate to enhance the stability of the laser interferometer is being planned, and other key techniques included in the space laser interferometer such as laser pointing modulation and laser phase-locking control are to be implanted into this prototype are under consideration.

Li, Yu-qiong; Luo, Zi-ren; Liu, He-shan; Dong, Yu-hui; Jin, Gang

2014-12-01

154

Corrections to correlators in p{sub t} fluctuation measurements  

SciTech Connect

Correction terms generated in the correlator analysis due to multiplicity-dependent observable mean are investigated. A procedure for the subtraction of correction terms from the correlators evaluated at fixed observed multiplicity is described. Benefits from the measurement of higher-order correlators are briefly discussed.

Filip, Peter [Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia and LHEP, JINR Dubna (Russian Federation)

2008-09-15

155

Measuring the effects of geographical distance on stock market correlation  

E-print Network

Measuring the effects of geographical distance on stock market correlation Stefanie Eckela , Gunter, Germany Abstract Recent studies suggest that the correlation of stock returns increases with decreasing it with an approach from spatial statistics, the mark correlation function. For the stocks contained in the S&P 500

Schmidt, Volker

156

Lifetime and diffusion length measurements on silicon material and solar cells  

NASA Technical Reports Server (NTRS)

Experimental methods were evaluated for the determination of lifetime and diffusion length in silicon intentionally doped with potentially lifetime-degrading impurities found in metallurgical grade silicon, impurities which may be residual in low-cost silicon intended for use in terrestrial flat-plate arrays. Lifetime measurements were made using a steady-state photoconductivity method. Diffusion length determinations were made using short-circuit current measurements under penetrating illumination. Mutual consistency among all experimental methods was verified, but steady-state photoconductivity was found preferable to photoconductivity decay at short lifetimes and in the presence of traps. The effects of a number of impurities on lifetime in bulk material, and on diffusion length in cells fabricated from this material, were determined. Results are compared with those obtained using different techniques. General agreement was found in terms of the hierarchy of impurities which degrade the lifetime.

Othmer, S.; Chen, S. C.

1978-01-01

157

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

158

Traceability transfer in high accuracy contact temperature measurements for length interferometry  

NASA Astrophysics Data System (ADS)

Some relevant components of uncertainty in interferometric measurements are associated with temperature measurements of material standards. This paper proposes a traceability transfer chain through a high accuracy contact temperature measurement system towards other temperature measurements systems. Those are traced to the best national metrological references in appropriate configurations for gauge-block length calibrations, allowing in that way investigations of effects and uncertainty components linked to temperature measurement of those blocks as further reductions in these uncertainties. As an application example a study of temperature gradients on gauge blocks is shown

Costa, P. A.; Bessa, M. S.; Schutz, J. S.; Azeredo, C. L. S.; França, R. S.; Quelhas, K. N.; Malinovski, I.

2015-01-01

159

Direct Comparison of Flow-FISH and qPCR as Diagnostic Tests for Telomere Length Measurement in Humans  

PubMed Central

Telomere length measurement is an essential test for the diagnosis of telomeropathies, which are caused by excessive telomere erosion. Commonly used methods are terminal restriction fragment (TRF) analysis by Southern blot, fluorescence in situ hybridization coupled with flow cytometry (flow-FISH), and quantitative PCR (qPCR). Although these methods have been used in the clinic, they have not been comprehensively compared. Here, we directly compared the performance of flow-FISH and qPCR to measure leukocytes' telomere length of healthy individuals and patients evaluated for telomeropathies, using TRF as standard. TRF and flow-FISH showed good agreement and correlation in the analysis of healthy subjects (R2?=?0.60; p<0.0001) and patients (R2?=?0.51; p<0.0001). In contrast, the comparison between TRF and qPCR yielded modest correlation for the analysis of samples of healthy individuals (R2?=?0.35; p<0.0001) and low correlation for patients (R2?=?0.20; p?=?0.001); Bland-Altman analysis showed poor agreement between the two methods for both patients and controls. Quantitative PCR and flow-FISH modestly correlated in the analysis of healthy individuals (R2?=?0.33; p<0.0001) and did not correlate in the comparison of patients' samples (R2?=?0.1, p?=?0.08). Intra-assay coefficient of variation (CV) was similar for flow-FISH (10.8±7.1%) and qPCR (9.5±7.4%; p?=?0.35), but the inter-assay CV was lower for flow-FISH (9.6±7.6% vs. 16±19.5%; p?=?0.02). Bland-Altman analysis indicated that flow-FISH was more precise and reproducible than qPCR. Flow-FISH and qPCR were sensitive (both 100%) and specific (93% and 89%, respectively) to distinguish very short telomeres. However, qPCR sensitivity (40%) and specificity (63%) to detect telomeres below the tenth percentile were lower compared to flow-FISH (80% sensitivity and 85% specificity). In the clinical setting, flow-FISH was more accurate, reproducible, sensitive, and specific in the measurement of human leukocyte's telomere length in comparison to qPCR. In conclusion, flow-FISH appears to be a more appropriate method for diagnostic purposes. PMID:25409313

Gutierrez-Rodrigues, Fernanda; Santana-Lemos, Bárbara A.; Scheucher, Priscila S.; Alves-Paiva, Raquel M.; Calado, Rodrigo T.

2014-01-01

160

Morphological features and length measurements of fetal lateral ventricles at 16-25 weeks of gestation by magnetic resonance imaging.  

PubMed

Normal growth of the lateral ventricles (LVs) was characterized three-dimensionally using magnetic resonance imaging (MRI) data from 16 human fetuses at 16-25 weeks of gestation. The LV was differentiated into 4 primary regions, the anterior horn, central parts, posterior horn, and inferior horn, at 16 weeks of gestation. The LV changed shape mainly by elongation and narrowing, which correspond to the external and internal growth of the surrounding cerebrum. Six length parameters measured in the LV correlated with biparietal diameter by simple regression analysis (R(2) range, 0.56-0.93), which may be valuable for establishing a standardized prenatal protocol to assess fetal well-being and development across intrauterine periods. No correlation was found between biparietal diameter and LV volume (R(2) =0.13). PMID:25059317

Taketani, Kaori; Yamada, Shigehito; Uwabe, Chigako; Okada, Tomohisa; Togashi, Kaori; Takakuwa, Tetsuya

2014-07-24

161

Correlation effects in the optical spectra of porphyrin oligomer chains: Exciton confinement and length dependence  

NASA Astrophysics Data System (ADS)

Excited states of ethylene-linked free-base porphyrin oligomers and polymer are studied using many-body perturbation theory (MBPT) within the GW approximation and the Bethe-Salpeter equation. Trends in the electronic levels with oligomer length are analysed and the correct long-range behaviour in the band gap is obtained. High polarizabilities and strong redshifts in the optical absorption peaks are predicted in agreement with observations on other strongly conjugated oligoporphyrins. We explain these trends by means of spatial and spectral analyses of the exciton character. Although Wannier-Mott and charge-transfer excitons are identified in the optical spectra, the strongest polarizabilities are actually associated with small, tightly bound excitons (Frenkel-like), in contrast to expectations. Furthermore, the common procedure of extrapolating polymer properties from oligomer calculations is examined from a MBPT perspective.

Hogan, Conor; Palummo, Maurizia; Gierschner, Johannes; Rubio, Angel

2013-01-01

162

Measurement of Optical Path Length for Cerebral Near-Infrared Spectroscopy in Newborn Infants  

Microsoft Academic Search

The time taken for an extremely short pulse of near-infrared laser light to traverse the heads of 6 preterm infants was measured after death. The values obtained were used to calculate a differential path length factor (DPF), defined as the mean distance travelled by the photons divided by the distance between the points where light entered and left the head.

J. S. Wyatt; M. Cope; D. T. Delpy; P. van der Zee; S. R. Arridge; A. D. Edwards; E. O. R. Reynolds

1990-01-01

163

Single-arm three-wave interferometer for measuring dispersion of short lengths of fiber  

E-print Network

on system parameters, such as required bandwidth, wavelength resolution, and fiber length, are discussed fiber and picosecond pulses from semiconductor film lasers," IEEE J. Lightwave Technol. 2, 464-468 (1984 phase-shift method for the measure of the chromatic dispersion in a single-mode fiber coiled on a cover

Qian, Li

164

Improved photovoltaic method for measurement of minority carrier diffusion length applied to silicon solar cells  

Microsoft Academic Search

The photovoltage spectrum measured on back illuminated silicon solar cells of the (passivated emitor solar cell) (PESC) type without original bottom ohmic electrode is evaluated with the aim to find the diffusion length of minority carriers in bulk of the absorber (L). Two junctions, namely pn+ junction of the cell and that spontaneously created on the free surface generally exist

J. Toušek; D. Kindl; J. Toušková; S. Dolhov

2001-01-01

165

ESTIMATION OF SOYBEAN ROOT LENGTH DENSITY DISTRIBUTION WITH DIRECT AND SENSOR BASED MEASUREMENTS OF CLAYPAN MORPHOLOGY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hydrologic and morphological properties of claypan landscapes cause variability in soybean root and shoot biomass. This study was conducted to develop predictive models of soybean root length density distribution (RLDd) using direct measurements and sensor based estimators of claypan morphology. A c...

166

Acoustic method for measuring the sound speed of gases over small path lengths  

E-print Network

Acoustic method for measuring the sound speed of gases over small path lengths J. S. Olfert,a M. D, Canada Received 9 February 2007; accepted 8 April 2007; published online 9 May 2007 Acoustic "phase shift this method the discrete acoustic wave and phase detection DAWPD method. Experimental results show

167

Learning to Measure Length in the First Three Years of School  

ERIC Educational Resources Information Center

Much research on early measurement learning is small-scale and dependent on the items used. While such research is helpful for indicating the key aspects of learning length, it does not give teachers a clear indication of the expectations for student learning of them. This paper presents substantial data from a large project that used individual…

McDonough, Andrea; Sullivan, Peter

2011-01-01

168

High-temperature laser interferometer for thermal expansion and optical-length measurements  

Microsoft Academic Search

A simple laser interferometer has been utilized to measure the thermal expansion and optical-length variation with temperature of highly reactive fluorides at high temperatures. The interferometer is a modification of the Jamin interferometer in which a laser beam is split into two parallel beams which traverse nearly identical paths and are reflected from the sample and a reference mirror. The

T. S. AuroraS; S. M. Day; V. King; D. O. Pederson

1984-01-01

169

Attenuation length measurements of liquid scintillator with LabVIEW and reliability evaluation of the device  

E-print Network

The attenuation length measuring device was constructed by using oscilloscope and LabVIEW for signal acquisition and processing. The performance of the device has been tested with a variety of ways, the test results show that the set-up has a good stability and high precision (sigma/mean reached 0.4 percent). Besides, the accuracy of the measurement system will decrease by about 17 percent if a filter is used. The attenuation length of gadolinium-loaded liquid scintillator (Gd-LS) was measured as 15.10 plus or minus 0.35 m where Gd-LS was heavily used in Daya Bay Neutrino Experiment. In addition, one method based on the Beer-Lambert law was proposed to investigate the reliability of the measurement device, the R-square reached 0.9995. Moreover, three purification methods for Linear Alkyl Benzene (LAB) production were compared in the experiment.

L. Gao; BX. Yu; YY. Ding; L. Zhou; LJ. Wen; YG. Xie; ZG. Wang; X. Cai; XL. Sun; J. Fang; Z. Xue; AW. Zhang; QW. LÜ; LJ. Sun; YS. Ge; YB. Liu; SL. Niu; T. Hu; J. Cao; JG. LÜ

2013-05-07

170

Attenuation length measurements of liquid scintillator with LabVIEW and reliability evaluation of the device  

E-print Network

The attenuation length measuring device was constructed by using oscilloscope and LabVIEW for signal acquisition and processing. The performance of the device has been tested with a variety of ways, the test results show that the set-up has a good stability and high precision (sigma/mean reached 0.4 percent). Besides, the accuracy of the measurement system will decrease by about 17 percent if a filter is used. The attenuation length of gadolinium-loaded liquid scintillator (Gd-LS) was measured as 15.10 plus or minus 0.35 m where Gd-LS was heavily used in Daya Bay Neutrino Experiment. In addition, one method based on the Beer-Lambert law was proposed to investigate the reliability of the measurement device, the R-square reached 0.9995. Moreover, three purification methods for Linear Alkyl Benzene (LAB) production were compared in the experiment.

Gao, L; Ding, YY; Zhou, L; Wen, LJ; Xie, YG; Wang, ZG; Cai, X; Sun, XL; Fang, J; Xue, Z; Zhang, AW; LÜ, QW; Sun, LJ; Ge, YS; Liu, YB; Niu, SL; Hu, T; Cao, J; LÜ, JG

2013-01-01

171

Focal length measurement of a microlens-array by grating shearing interferometry.  

PubMed

Based on grating shearing interferometry, a simple technique is introduced for focal length measurements of a microlens-array (MLA). The measurement system is composed of a He-Ne laser, condenser, collimator, the MLA under testing, a Ronchi grating, and CCD sensor. The plane wavefront from the collimator is transformed to a spherical wavefront by the MLA, while the curvature center is at the focus. Interference stripes appear at the overlap between the zero-order and first-order diffractive patterns of the grating and are detected by the CCD sensor. By analyzing the period change of stripes, the focal length is determined after the defocus of the grating is calculated. To validate the feasibility, an experiment is performed. The measurement uncertainty is discussed and measurement accuracy was determined to be 2%. PMID:25322367

Zhu, Xianchang; Hu, Song; Zhao, Lixin

2014-10-10

172

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

173

Measuring correlations between non-stationary series with DCCA coefficient  

NASA Astrophysics Data System (ADS)

In this short report, we investigate the ability of the DCCA coefficient to measure correlation level between non-stationary series. Based on a wide Monte Carlo simulation study, we show that the DCCA coefficient can estimate the correlation coefficient accurately regardless the strength of non-stationarity (measured by the fractional differencing parameter d). For a comparison, we also report the results for the standard Pearson correlation coefficient. The DCCA coefficient dominates the Pearson coefficient for non-stationary series.

Kristoufek, Ladislav

2014-05-01

174

Correlation measures in bipartite states and entanglement irreversibility  

E-print Network

We derive quantitative relations among several naturally defined measures of classical and nonclassical correlations in a bipartite quantum state. We also obtain an upper bound of entanglement irreversibility and a sufficient condition for reversible entanglement. The additivity of entanglement of formation is directly related to the additivity of quantum discord as well as a certain measure of classical correlation.

Shengjun Wu

2012-07-24

175

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

176

Multichannel analysis of correlation length of SEVIRI images around ground-based cloud observatories to determine their representativeness  

NASA Astrophysics Data System (ADS)

Images of the geostationary Meteosat-9 SEVIRI instrument during the year 2012 are analyzed with respect to the representativeness of the observations of eight cloud observatories in Europe. Cloudy situations are selected to get a time series for every pixel in a 300 km × 300 km area centered around each ground station. Then the Pearson correlation coefficient of each time series to the one of the pixel nearest to the corresponding ground site is calculated. The area for which a station is representative is defined by the characteristic radius around each station for each SEVIRI channel, where the average correlation falls below 0.9. It is found that measurements in the visible and near infrared channels, which respond to cloud microphysics, are correlated in an area with a 1 to 4 km radius, while the thermal channels, that correspond to cloud top temperature, are correlated to a distance of about 20 km. The defined radius even increases for the water vapor and ozone channels. While all stations in Central Europe are quite alike, the correlations around the station in the mountains of southern Italy are much lower. Additionally correlations at different distances corresponding to the grid box sizes of forecast models were compared. The results show good comparability between regional forecast models (grid size ? 10 km) and ground-based measurements since the correlations in less than 10 km distance are in all cases higher than 0.8. For larger distances like they are typical for global models (grid size ? 20 km) the correlations decrease to 0.6, especially for shortwave measurements and corresponding cloud products. By comparing daily means, the characteristic radius of each station is increased to about 3 to 10 times the value of instantaneous measurements and also the comparability to models grows.

Slobodda, J.; Hünerbein, A.; Lindstrot, R.; Preusker, R.; Ebell, K.; Fischer, J.

2014-06-01

177

Cervical Length Measured by Transvaginal Ultrasonography and Cervicovaginal Infection as Predictor of Preterm Birth Risk  

PubMed Central

Introduction: The study shows possibilities of transvaginal sonographic measurement of the cervix in prediction of premature birth risk. Goals: The aim of the study was to follow up the cervical length in the pregnant from 16th to 37th week, as well as to do a microbiological analysis of the vaginal and cervical flora and to identify relation between the cervical shortening and microbiological flora as well as with a premature birth. Material and methods: The investigation was conducted as a prospective study on two groups of female patients in Clinical Centre of Banja Luka. In the high risk group we had 8% of patients with cervical length bellow than 15mm, 30% of patients with cervical length from 15 to 25m and 62% of patients with cervical length bigger than 25mm. In the low risk group we had no patients with cervical length bellow 15mm, 95% of patients had cervical length bigger than 25mm and 5% of patients had cervical length from 15 do 25mm. Results: The regression coefficient of the cervical length in the high risk group was 0.44mm, while in the low risk group it was 0.26mm. In the high risk group 67.56% patients had a positive cervical smear finding, while in the low risk group it was 4%. A high premature birth (defined as birth before 36.6 weeks) incidence of 50% was presented in patients with cervical length bellow 15mm. In the group of patients with cervical length up to 25mm the premature risk incidence was 10.52±0.05. In the high risk group of patients with a positive cervical smear finding, regarding the cervical length the percentage was as follows; in the subgroup of 15mm length 88,89±11,87, in subgroup from 15 to 25mm was 62,07±11,43 and in the subgroup bigger than 25mm, 60.06±8.05. Conclusion: By the analysis of the first and second goal of our study we can conclude that ultrasound assessment of cervical length is simple and feasible in the 16th week of pregnancy in both groups, with high and low risk. The length of the cervix in this period is shorter in the high risk group compared with the low-risk group. This difference was not statistically significant, however, it clearly demonstrated connection between shorten length of the cervix with the preterm birth. A regression analysis shows that the shortening of the cervix length is more frequent in high risk group which is to be expected, bearing in mind that in this group, the risk of preterm delivery was significantly higher. PMID:24825940

Banicevic, Arnela Ceric; Popovic, Miroslav; Ceric, Amela

2014-01-01

178

Photon path length distributions for cloudy skies  oxygen A-Band measurements and model calculations  

NASA Astrophysics Data System (ADS)

This paper addresses the statistics underlying cloudy sky radiative transfer (RT) by inspection of the distribution of the path lengths of solar photons. Recent studies indicate that this approach is promising, since it might reveal characteristics about the diffusion process underlying atmospheric radiative transfer (Pfeilsticker, 1999). Moreover, it uses an observable that is directly related to the atmospheric absorption and, therefore, of climatic relevance. However, these studies are based largely on the accuracy of the measurement of the photon path length distribution (PPD). This paper presents a refined analysis method based on high resolution spectroscopy of the oxygen A-band. The method is validated by Monte Carlo simulation atmospheric spectra. Additionally, a new method to measure the effective optical thickness of cloud layers, based on fitting the measured differential transmissions with a 1-dimensional (discrete ordinate) RT model, is presented. These methods are applied to measurements conducted during the cloud radar inter-comparison campaign CLARE’98, which supplied detailed cloud structure information, required for the further analysis. For some exemplary cases, measured path length distributions and optical thicknesses are presented and backed by detailed RT model calculations. For all cases, reasonable PPDs can be retrieved and the effects of the vertical cloud structure are found. The inferred cloud optical thicknesses are in agreement with liquid water path measurements.

Funk, O.; Pfeilsticker, K.

2003-03-01

179

Persistence Length of Titin from Rabbit Skeletal Muscles Measured with Scattering and Microrheology Techniques  

PubMed Central

The persistence length of titin from rabbit skeletal muscles was measured using a combination of static and dynamic light scattering, and neutron small angle scattering. Values of persistence length in the range 9–16 nm were found for titin-II, which corresponds to mainly physiologically inelastic A-band part of the protein, and for a proteolytic fragment with 100-nm contour length from the physiologically elastic I-band part. The ratio of the hydrodynamic radius to the static radius of gyration indicates that the proteins obey Gaussian statistics typical of a flexible polymer in a ?-solvent. Furthermore, measurements of the flexibility as a function of temperature demonstrate that titin-II and the I-band titin fragment experience a similar denaturation process; unfolding begins at 318 K and proceeds in two stages: an initial gradual 50% change in persistence length is followed by a sharp unwinding transition at 338 K. Complementary microrheology (video particle tracking) measurements indicate that the viscoelasticity in dilute solution behaves according to the Flory/Fox model, providing a value of the radius of gyration for titin-II (63 ± 1 nm) in agreement with static light scattering and small angle neutron scattering results. PMID:15792980

Di Cola, Emanuela; Waigh, Thomas A.; Trinick, John; Tskhovrebova, Larissa; Houmeida, Ahmed; Pyckhout-Hintzen, Wim; Dewhurst, Charles

2005-01-01

180

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

181

Measurement of coherence length and incoherent source size of hard x-ray undulator beamline at Pohang Light Source-II.  

PubMed

We measured the spatial coherence length and incoherent source size of a hard x-ray undulator beamline at Pohang Light Source-II, the stored electron energy of which has been increased from 2.5 GeV to 3 GeV. The coherence length was determined by single-slit measurement of the visibility of the Fresnel diffraction pattern. The correlated incoherent source size was cross-checked for three different optics: the single slit, beryllium parabolic compound refractive lenses, and the Fresnel zone plate. We concluded that the undulator beamline has an effective incoherent source size (FWHM) of 540 ?m (horizontal) × 50 ?m (vertical). PMID:24784668

Park, So Yeong; Hong, Chung Ki; Lim, Jun

2014-04-01

182

Measurement of coherence length and incoherent source size of hard x-ray undulator beamline at Pohang Light Source-II  

SciTech Connect

We measured the spatial coherence length and incoherent source size of a hard x-ray undulator beamline at Pohang Light Source-II, the stored electron energy of which has been increased from 2.5 GeV to 3 GeV. The coherence length was determined by single-slit measurement of the visibility of the Fresnel diffraction pattern. The correlated incoherent source size was cross-checked for three different optics: the single slit, beryllium parabolic compound refractive lenses, and the Fresnel zone plate. We concluded that the undulator beamline has an effective incoherent source size (FWHM) of 540 ?m (horizontal) × 50 ?m (vertical)

Park, So Yeong; Hong, Chung Ki [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of)] [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of); Lim, Jun, E-mail: limjun@postech.ac.kr [Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of)] [Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of)

2014-04-15

183

Fan Blade Deflection Measurement and Analyses Correlation  

NASA Technical Reports Server (NTRS)

Steady deflection measurements were taken of two identical NASA/Pratt & Whitney-designed fan blades while they were rotating in a vacuum in NASA Lewis Research Center's Dynamic Spin Facility. The one-fifth-scale fan blades, which have a tip diameter of 22 in. and a pinroot retention, are of sparshell construction and were unducted for this test. The purpose of the test was to measure the change of the radial deflection of the blade tip and blade angle at selected radial stations along the blade span with respect to rotational speed. The procedure for radial deflection measurement had no precedent and was newly developed for this test. Radial deflection measurements were made to assure adequate tip clearance existed between the fan blades and the duct for a follow-on wind tunnel test. Also, blade angle deflection measurements were desired before pitchsetting parts for the wind tunnel test were finish machined. During the test, laser beams were aimed across the blade path into photodiodes to give signals that were used to determine blade angle change or tip radial deflection. These laser beams were set parallel to the spin axis at selected radial stations.

Mehmed, Oral; Janetzke, David C.

1997-01-01

184

Single-arm three-wave interferometer for measuring dispersion of short lengths of fiber.  

PubMed

We present a simple fiber-based single-arm spectral interferometer to measure directly the second-order dispersion parameter of short lengths of fiber (< 50 cm). The standard deviation of the measured dispersion on a 39.5-cm-long SMF28(TM) fiber is 1x10(-4) ps/nm, corresponding to 1% relative error, without employing any curve fitting. Our technique measures the second-order dispersion by examining the envelope of the interference pattern produced by three reflections: two from the facets of the test fiber and one from a mirror placed away from the fiber facet at a distance that introduces the same group delay as the test fiber at the measured wavelength. The operational constraints on system parameters, such as required bandwidth, wavelength resolution, and fiber length, are discussed in detail. Experimental verification of this technique is carried out via comparison of measurements of single mode fiber (SMF28(TM)) with published data and via comparison of measurements of a dispersion compensating fiber with those taken using conventional techniques. Moreover, we used this new technique to measure the dispersion coefficient of a 45-cm-long twin-hole fiber over a 70 nm bandwidth. It is the first time dispersion measurement on this specialty fiber is reported. PMID:19550980

Galle, Michael A; Mohammed, Waleed S; Qian, Li; Smith, Peter W

2007-12-10

185

Precision measurement of the n-4He scattering length using neutron interferometry  

NASA Astrophysics Data System (ADS)

The NIST neutron interferometer and optics facility (NIOF) is currently performing a precision measurement of the n-4He scattering length to less than 0.3% relative uncertainty. A neutron interferometer consists of a perfect silicon crystal machined such that there are three separate blades on a common base. Neutrons entering the interferometer are Bragg diffracted in the blades to produce two spatially separate yet coherent beam paths much like an optical Mach-Zehnder interferometer. A sample placed in one of the beam paths of the interferometer causes a phase difference between the two paths. This phase difference is directly related to the sample's scattering length. Neutron scattering lengths are one parameter that can be predicted using advanced theoretical models describing two and three nucleon interactions. In an effort to provide tests and/or benchmarks of these theoretical models, the NIOF has already performed precision measurements of neutron scattering lengths to less than 1% relative uncertainty in several low Z gases: H, D, 3He, and polarized 3He. A preliminary result of this work will be given.

Huber, M. G.; Arif, M.; Jacobson, D. L.; Pushin, D. A.; Abutaleb, M. O.; Black, T. C.; Shahi, C. B.; Wietfeldt, F. E.

2010-11-01

186

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. PMID:23258416

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

2013-01-01

187

Long focal-length measurement using divergent beam and two gratings of different periods.  

PubMed

A new accurate method for long focal-length measurement based on Talbot interferometry is proposed. A divergent beam and two Ronchi gratings of different periods are employed, as the alternative of the collimated beam and two identical gratings, to achieve higher measurement accuracy. Moreover, with divergent beam, lenses of large aperture can be easily measured without scanning, which is required when it comes to traditional collimated beam. Numerical analysis and experiments were carried out. The results demonstrate the proposed method features remarkably high accuracy and repeatability. PMID:25402033

Luo, Jia; Bai, Jian; Zhang, Jinchun; Hou, Changlun; Wang, Kaiwei; Hou, Xiyun

2014-11-17

188

Correlation of creatine kinase and gait measurement in the postpolio population: a corrected version.  

PubMed

Measurements of stride length, gait speed, and distance walked during seven days were obtained from 15 postpolio and eight control subjects. Pedometers were used to measure distance walked. Measurements of stride length and speed were performed three times, and there was a high correlation between tests (R = .852-.969). The pedometers failed to record accurately in some postpolio subjects, and these subjects were dropped from analysis when ambulation distance was used as a variable. There were significant differences between the postpolio subjects and controls with respect to gait speed (47.7 +/- 14.0 vs 74.9 +/- 15.9 m/min, p less than 0.0005), stride length (55.3 +/- 11.7 vs 69.8 +/- 8.6 cm, p = .006), and average kilometers walked per day for seven days (1.97 +/- 1.3 vs 3.89 +/- 1.7, p = .016). The postpolio subjects had their serum creatine kinase (CK) levels measured at the end of the study. Forty percent of subjects had a level above the normal limits of our laboratory. There was a significantly positive correlation between CK levels and the distance walked during the previous 24 hours (R = .75, p = .012). The findings of this study illustrate the impact of gait abnormalities on the ambulatory abilities of the postpolio population. The correlation of CK with ambulation supports the association of exercise as a source of elevated CK levels in the postpolio population. PMID:1580772

Waring, W P; McLaurin, T M

1992-05-01

189

Correlation of creatine kinase and gait measurement in the postpolio population.  

PubMed

Measurements of stride length, gait speed, and distance walked during seven days were obtained from 15 postpolio and eight control subjects. Pedometers were used to measure distance walked. Measurements of stride length and speed were performed three times, and there was a high correlation between tests (R = .852-.969). The pedometers failed to record accurately in some postpolio subjects, and these subjects were dropped from analysis when ambulation distance was used as a variable. There were significant differences between the postpolio subjects and controls with respect to gait speed (47.7 +/- 14.0 vs 74.9 +/- 15.9m/min, p less than 0.0005), stride length (55.3 +/- 11.7 vs 69.8 +/- 8.6cm, p = .006), and average kilometers walked per day for seven days (1.97 +/- 1.3 vs 3.89 +/- 1.7, p = .016). The postpolio subjects had their serum creatine kinase (CK) levels measured at the end of the study. Forty percent of subjects had a level above the normal limits of our laboratory. There was a significantly positive correlation between CK levels and the distance walked during the previous 24 hours (R = .75, p = .012). The findings of this study illustrate the impact of gait abnormalities on the ambulatory abilities of the postpolio population. The correlation of CK with ambulation supports the association of exercise as a source of elevated CK levels in the postpolio population. PMID:1729970

Waring, W P; McLaurin, T M

1992-01-01

190

Adherence to Criteria for Transvaginal Ultrasound Imaging and Measurement of Cervical Length  

PubMed Central

Background Adherence to published criteria for transvaginal imaging and measurement of cervical length is uncertain. We sought to assess adherence by evaluating images submitted to certify research sonographers for participation in a clinical trial. Study Design We reviewed qualifying test results of sonographers seeking certification to image and measure cervical length in a clinical trial. Participating sonographers were required to access training materials and submit 15 images, three each from five pregnant women not enrolled in the trial. One of two sonologists reviewed all qualifying images. We recorded the proportion of images that did not meet standard criteria (excess compression, landmarks not seen, improper image size, or full maternal bladder) and the proportion in which the cervical length was measured incorrectly. Failure for a given patient was defined as more than one unacceptable image, or more than two acceptable images with incorrect caliper placement or erroneous choice of the “shortest best” cervical length. Certification required satisfactory images and cervical length measurement from four or more patients. Results 327 sonographers submitted 4905 images. 271 sonographers (83%) were certified on the first, 41 (13%) on the second, and 2 (0.6%) on the third submission. 13 never achieved certification. Of 314 who passed, 196 submitted 15 acceptable images that were appropriately measured for all five women. There were 1277 deficient images: 493 were acceptable but incorrectly measured images from sonographers who passed certification because mis-measurement occurred no more than twice. Of 784 deficient images submitted by sonographers who failed the certification, 471 were rejected because of improper measurement (caliper placement and/or failure to identify the shortest best image), and 313 because of failure to obtain a satisfactory image (excessive compression, required landmarks not visible, incorrect image size, brief examination, and/or full maternal bladder) Conclusion Although 83% of sonographers were certified on their first submission, more than one in four ultrasound images submitted did not meet published quality criteria. Increased attention to standardized education and credentials is warranted for persons who perform ultrasound examinations of the cervix in pregnancy. PMID:23958649

Iams, JD; Grobman, WA; Lozitska, A; Spong, CY; Saade, G; Mercer, BM; Tita, AN; Rouse, DJ; Sorokin, Y; Wapner, RJ; Leveno, KJ; Esplin, MS; Tolosa, JE; Thorp, JM; Caritis, SN; Van Dorsten, JP

2014-01-01

191

Electron-Gamma-Angular Correlation Measurements in Radioactive Decay  

Microsoft Academic Search

The beta-gamma angular correlations in the decay of a number of nuclides have been studied as a function of the beta-ray energy. Isotropic correlations were found in the decay of Co55, Co56, Co60, Na22, Na24, Cs134, and I124. Non-isotropic correlations have been measured in the decay of Rb86, Sb124, and I126. The interpretation of these results in terms of the

Donald T. Stevenson; Martin Deutsch

1951-01-01

192

Measurement of the temperature dependence of pulse lengths in an n-type germanium detector  

E-print Network

The temperature dependence of the pulse length was measured for an 18-fold segmented n-type germanium detector in the temperature range of 77-120 K. The interactions of 122 keV photons originating from a Europium-152 source were selected and pulses as observed on the core and segment electrodes were studied. In both cases, the temperature dependence can be well described by a Boltzmann-like ansatz.

I. Abt; A. Caldwell; J. Liu; B. Majorovits; O. Volynets

2011-12-21

193

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

194

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

195

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

196

Ultrasonic measurement of stress in railroad wheels and in long lengths of welded rail  

NASA Technical Reports Server (NTRS)

The failure of high speed emergency braking is discussed for railroad wheels and track. It is shown that high compressive residual stresses exist in the rims of new wheels which generate excessive heat, reducing the stress levels. Thermal stresses that build up in continuous lengths of welded track are reported and nondestructive methods of measuring stresses in thick steel are presented for identification, replacement, or adjustment before hazardous failures occur.

Clotfelter, W. N.; Risch, E. R.

1974-01-01

197

Turbulence spectra and length scales measured in film coolant flows emerging from discrete holes  

SciTech Connect

To date, very little attention has been devoted to the scales and turbulence energy spectra of coolant exiting from film cooling holes. Length-scale documentation and spectral measurements have primarily been concerned with the free-stream flow with which the coolant interacts. Documentation of scales and energy decomposition of the coolant flow leads to more complete understanding of this important flow and the mechanisms by which it disperses and mixes with the free stream. CFD modeling of the emerging flow can use these data as verification that flow computations are accurate. To address this need, spectral measurements were taken with single-sensor, hot-wire anemometry at the exit plane of film cooling holes. Energy spectral distributions and length scales calculated from these distributions are presented for film cooling holes of different lengths and for coolant supply plenums of different geometries. Measurements are presented on the hole streamwise centerline at the center of the hole, one-half diameter upstream of center, and one-half diameter downstream of center. The data highlight some fundamental differences in energy content, dominant frequencies, and scales with changes in the hole and plenum geometries. Coolant flowing through long holes exhibits smoothly distributed spectra as might be anticipated in fully developed tube flows. Spectra from short-hole flows, however, show dominant frequencies.

Burd, S.W. [Pratt and Whitney Florida, West Palm Beach, FL (United States). Combustor Module Center; Simon, T.W. [Univ. of Minnesota, Minneapolis, MN (United States). Heat Transfer Lab.

1999-07-01

198

Corpus Callosum Measurements Correlate with Developmental Delay in Smith-Lemli-Opitz Syndrome  

PubMed Central

Background Smith-Lemli-Opitz syndrome (SLOS) is a multiple malformation, neurodevelopmental disorder of cholesterol metabolism caused by mutations in 7-dehydrocholesterol reductase (DHCR7). Corpus callosum (CC) malformations and developmental delay are common manifestations of this disorder, but the relationship between the two has not been evaluated. We tested the hypothesis that shorter callosal length and smaller area correlates with higher serum 7-dehydrocholesterol (7DHC) and increased severity of neurodevelopmental delay in a large cohort of SLOS patients. Methods Thirty-six individuals with SLOS (18M/18F) between 0.20 and 12.5 years (mean = 3.9, SD = 3.6) and 36 typically developing controls (18M/18F) between 0.12 and 12.8 years (mean = 4.0, SD = 3.6) were each imaged one time on a 1.5T MR scanner. One mid-sagittal image per study was selected for manual measurement of CC cross-sectional area and length. Gross motor, fine motor, and language developmental quotients, anatomical severity score, and serum sterol levels were assessed with imaging measurements. Results Shorter CC length and smaller area correlated with lower developmental quotient in gross motor and language domains. Furthermore, length and area negatively correlated with a serum 7DHC, 8DHC, sterol ratio, and anatomical severity score, and positively correlated with total cholesterol. The degree of developmental delay ranged from mild to severe, involving all domains. Conclusions For individuals with SLOS, smaller callosal area and length are associated with higher serum 7DHC, anatomic severity, and motor and language delay. These findings suggest the relationship between callosal development, biochemistry, and neurodevelopment may lead to finding predictors of outcome in SLOS. PMID:23859856

Lee, Ryan W.Y.; Yoshida, Shoko; Jung, Eun Sol; Mori, Susumu; Baker, Eva H.; Porter, Forbes D.

2013-01-01

199

Speckle correlation used for measuring microstructural changes in paper  

Microsoft Academic Search

In this paper the use of laser speckle correlation as a mean to measure the micro-structural changes in paper exposed to a changing environment will be presented. Of particular interest will be changes in humidity and crack propagation. Speckle correlation is a technique that calculates the local structural change in a speckle pattern as the object deforms in real time.

Mikael Sjödahl; Linda Larsson

2003-01-01

200

Automatic measurement of pennation angle and fascicle length of gastrocnemius muscles using real-time ultrasound imaging.  

PubMed

Muscle imaging is a promising field of research to understand the biological and bioelectrical characteristics of muscles through the observation of muscle architectural change. Sonomyography (SMG) is a technique which can quantify the real-time architectural change of muscles under different contractions and motions with ultrasound imaging. The pennation angle and fascicle length are two crucial SMG parameters to understand the contraction mechanics at muscle level, but they have to be manually detected on ultrasound images frame by frame. In this study, we proposed an automatic method to quantitatively identify pennation angle and fascicle length of gastrocnemius (GM) muscle based on multi-resolution analysis and line feature extraction, which could overcome the limitations of tedious and time-consuming manual measurement. The method started with convolving Gabor wavelet specially designed for enhancing the line-like structure detection in GM ultrasound image. The resulting image was then used to detect the fascicles and aponeuroses for calculating the pennation angle and fascicle length with the consideration of their distribution in ultrasound image. The performance of this method was tested on computer simulated images and experimental images in vivo obtained from normal subjects. Tests on synthetic images showed that the method could identify the fascicle orientation with an average error less than 0.1°. The result of in vivo experiment showed a good agreement between the results obtained by the automatic and the manual measurements (r=0.94±0.03; p<0.001, and r=0.95±0.02, p<0.001). Furthermore, a significant correlation between the ankle angle and pennation angle (r=0.89±0.05; p<0.001) and fascicle length (r=-0.90±0.04; p<0.001) was found for the ankle plantar flexion. This study demonstrated that the proposed method was able to automatically measure the pennation angle and fascicle length of GM ultrasound images, which made it feasible to investigate muscle-level mechanics more comprehensively in vivo. PMID:25465963

Zhou, Guang-Quan; Chan, Phoebe; Zheng, Yong-Ping

2015-03-01

201

Measurement and Correlation of Ice Accretion Roughness  

NASA Technical Reports Server (NTRS)

Measurements were taken of the roughness characteristics of ice accreted on NACA 0012 airfoils in the NASA Glenn Icing Research Tunnel (IRT). Tests were conducted with size scaled, using models with chords of 26.7, 53.3, and 80.0 cm, and with liquid-water content scaled, both according to previously-tested scaling methods. The width of the smooth zone which forms on either side of the leading edge of the airfoil and the diameter of the roughness elements are presented in non-dimensional form as functions of the accumulation parameter. The smooth-zone width was found to decrease with increasing accumulation parameter. The roughness-element diameter increased with accumulation parameter until a plateau was reached. This maximum diameter was about 0.06 times twice the model leading-edge radius. Neither smooth-zone width nor element diameter were affected by a change in freezing fraction from 0.2 to 0.4. Both roughness characteristics appeared to scale with model size and with liquid-water content.

Anderson, David N.; Hentschel, Daniel B.; Ruff, Gary A.

2003-01-01

202

Apparatus for Measurements of Time and Space Correlation  

NASA Technical Reports Server (NTRS)

A brief review is made of improvements to an experimental apparatus for time and space correlation designed for study of turbulence. Included is a description of the control of the measurements and a few particular applications.

Favre, Alexandre; Gaviglio, J; Dumas, R

1955-01-01

203

Photon path length distributions for cloudy atmospheres from GOSAT satellite measurements  

NASA Astrophysics Data System (ADS)

The presence of clouds in the atmosphere has significant influence on the photon paths of the scattered sunlight. Besides reflections of radiation at the cloud top, additional scattering events inside the cloud may occur and thus lengthening or shortening of the photon path in the atmosphere. Clouds consisting of multiple layers or patches may lead to a "ping pong" behaviour of the photons due to reflections at the individual surfaces. The objective of our study is the retrieval of photon path length distributions for various atmospheric cloud situations which will lead to a better understanding of the influence of clouds on the atmospheric radiative transport. Following principles from ground based photon path length retrieval (Funk et al., 2003), our research uses the combination of space based measurements of the oxygen A-band and radiative transfer simulations. The experimental spectra originate from the Japanese Greenhouse gases Observing SATellite (GOSAT), more precisely the Fourier Transform Spectrometer TANSO-FTS. Its high spectral resolution allows to almost completely resolve the individual absorption lines which is a prerequisite to our study. The Monte Carlo radiative transfer model McArtim (Deutschmann et al., 2011) is used to model the measured spectra. This model allows user-defined input for the altitude dependent cross sections and furthermore the incorporation of three dimensional cloud shapes and properties. From the simulation output and the sun-satellite geometry, photon path length distributions can be obtained. Distributions of photon path lengths are presented for a selection of GOSAT observations of entirely cloud covered atmospheres with similar measurement geometries.

Kremmling, Beke; Penning de Vries, Marloes; Wagner, Thomas

2014-05-01

204

Ultrasound Measurement of Cervical Length as Predictor of Threatened Preterm Birth: a Predictive Model  

PubMed Central

ABSTRACT Introduction: The incidence of preterm delivery has been increasing even in developed countries and remains a serious problem for fetuses and neonates. Although many predictors for preterm delivery have been proposed, complete prediction and prevention have not yet been established. Aims: To examine the potential association between sonographic measurement of cervical length and threatened preterm birth (TPTB) in pregnant woman at 24-36 weeks of gestation. Materials and methods: A cross-sectional study included a total of 360 pregnant woman at 24-36 weeks of gestation categorized in two groups: TPTB group (n=160) and non TPTB group (n=200). The study was carried out at the Department of Obstetrics and Gynecology of the Clinical Center University of Sarajevo (KCUS). Sociodemographic and clinical characteristics of patients were obtained from medical records and physical examination by gynecologist. Transvaginal sonography was carried out by GE Voluson 730. Results: There was a significant association between TPTB and sonographic measurement of cervical length <25 mm (P<0.001). The logistic regression model was statistically significant, x2(7) = 281.530, P<0. 001. The model explained 72.6% of the variance in TPTB and correctly classified 88.1% of cases. Sensitivity was 83.8%, specificity was 91.5%, positive predictive value was 88.7% and negative predictive value was 87.6%. Out of the 7 predictor variables only 5 were statistically significant: cervical length, cervical consistency, rupture of membranes, uterine contractions and amine odor test. Conclusion: The findings of this study suggest association between sonographic measurement of cervical length and TPTB. PMID:25568578

El-Ardat, Mohammad Abou; Gavrankapetanovic, Fatima; Abou El-Ardat, Khalil A.; Dekovic, Sanjin; Murtezic, Senad; Mehmedbasic, Eldar; Hiros, Nadja

2014-01-01

205

Bilateral step length estimation using a single inertial measurement unit attached to the pelvis  

PubMed Central

Background The estimation of the spatio-temporal gait parameters is of primary importance in both physical activity monitoring and clinical contexts. A method for estimating step length bilaterally, during level walking, using a single inertial measurement unit (IMU) attached to the pelvis is proposed. In contrast to previous studies, based either on a simplified representation of the human gait mechanics or on a general linear regressive model, the proposed method estimates the step length directly from the integration of the acceleration along the direction of progression. Methods The IMU was placed at pelvis level fixed to the subject's belt on the right side. The method was validated using measurements from a stereo-photogrammetric system as a gold standard on nine subjects walking ten laps along a closed loop track of about 25 m, varying their speed. For each loop, only the IMU data recorded in a 4 m long portion of the track included in the calibrated volume of the SP system, were used for the analysis. The method takes advantage of the cyclic nature of gait and it requires an accurate determination of the foot contact instances. A combination of a Kalman filter and of an optimally filtered direct and reverse integration applied to the IMU signals formed a single novel method (Kalman and Optimally filtered Step length Estimation - KOSE method). A correction of the IMU displacement due to the pelvic rotation occurring in gait was implemented to estimate the step length and the traversed distance. Results The step length was estimated for all subjects with less than 3% error. Traversed distance was assessed with less than 2% error. Conclusions The proposed method provided estimates of step length and traversed distance more accurate than any other method applied to measurements obtained from a single IMU that can be found in the literature. In healthy subjects, it is reasonable to expect that, errors in traversed distance estimation during daily monitoring activity would be of the same order of magnitude of those presented. PMID:22316235

2012-01-01

206

Assessing Long-Term Wind Conditions by Combining Different Measure-Correlate-Predict Algorithms: Preprint  

SciTech Connect

This paper significantly advances the hybrid measure-correlate-predict (MCP) methodology, enabling it to account for variations of both wind speed and direction. The advanced hybrid MCP method uses the recorded data of multiple reference stations to estimate the long-term wind condition at a target wind plant site. The results show that the accuracy of the hybrid MCP method is highly sensitive to the combination of the individual MCP algorithms and reference stations. It was also found that the best combination of MCP algorithms varies based on the length of the correlation period.

Zhang, J.; Chowdhury, S.; Messac, A.; Hodge, B. M.

2013-08-01

207

Report on Thermal Neutron Diffusion Length Measurement in Reactor Grade Graphite Using MCNP and COMSOL Multiphysics  

E-print Network

Neutron diffusion length in reactor grade graphite is measured both experimentally and theoretically. The experimental work includes Monte Carlo (MC) coding using 'MCNP' and Finite Element Analysis (FEA) coding suing 'COMSOL Multiphysics' and Matlab. The MCNP code is adopted to simulate the thermal neutron diffusion length in a reactor moderator of 2m x 2m with slightly enriched uranium ($^{235}U$), accompanied with a model designed for thermal hydraulic analysis using point kinetic equations, based on partial and ordinary differential equation. The theoretical work includes numerical approximation methods including transcendental technique to illustrate the iteration process with the FEA method. Finally collision density of thermal neutron in graphite is measured, also specific heat relation dependability of collision density is also calculated theoretically, the thermal neutron diffusion length in graphite is evaluated at $50.85 \\pm 0.3cm$ using COMSOL Multiphysics and $50.95 \\pm 0.5cm$ using MCNP. Finally the total neutron cross-section is derived using FEA in an inverse iteration form.

S. R. Mirfayzi

2013-01-08

208

Method of glass melter electrode length measurement using time domain reflectometry (TDR)  

SciTech Connect

The present invention overcomes the drawbacks inherent in the prior art and solves the problems inherent in conventional Joule-heated vitrification melters, where the melter preferably comprises a vessel having a refractory liner and an opening for receiving material which is converted into molten vitreous material in the vessel. The vessel has an outlet port for removing molten vitreous material from the vessel. A plurality of electrodes is disposed in the vessel and electrical energy is passed between electrode pairs through feed material and molten vitreous material in the vessel. Typically, the electrodes erode and wear in time, and this invention seeks to monitor and evaluate the length and condition of the electrodes. The present invention uses time domain reflectometry (TDR) methods to accurately measure the length of an electrode that is subject to wear and electrolytic decomposition due to the extreme conditions in which the electrode is required to operate. Specifically, TDR would be used to measure the length and effects of erosion of molybdenum electrodes used in Joule-heated vitrification melter. Of course, the inventive concept should not be limited to this preferred environment.

Tarpley, James M.; Zamecnik, John R.

2000-02-28

209

Standard Length versus Total Length  

Microsoft Academic Search

In an effort to determine the length measurement most representative of the bulk of the fish, the standard length and the total length were each compared with the weight of the fish. This comparison was made for four species of game fish, yellow perch (Perca flavescens), wall-eyed pike (Stizostedion v. vitreum), rock bass (Ambloplites rupestris), and lake trout (Cristivomer n.

William F. Royce

1942-01-01

210

Measurement of Critical correlations in an ultracold Bose gas by means of a temporal Talbot-Lau interferometery  

NASA Astrophysics Data System (ADS)

We report the results of a study of measuring the correlation length at the Lambda critical phase transition point in an ultra-cold Bose gas with a temporal Talbot-Lau (TL) interferometery. Near the critical temperature, the correlation length increase exponentially and its critical exponent factor is measured around 0.67, which is a universal value in quantum gas. In the experiment we filtered the fraction of condensate from the thermal cloud at the Lambda critical phase transition point by means of the TL interferometer technique.

Chen, Xuzong; Xiong, Wei; Zhai, Yueyang; Yue, Xuguang; Wu, Biao; Xiong, Hongwei; Zhou, Xiaoji

2014-04-01

211

Asynchronous quantum correlation: measurement acting as a beamsplitter  

E-print Network

A two-body quantum correlation is calculated for a particle either reflecting from a mirror, traversing a finite barrier/well, or trapped within an infinite well. Correlated interference results when the incident and reflected particle substates and their associated mirror (or barrier-well) substates overlap. Using the Copenhagen interpretation, an asynchronous joint probability density, which is a function both of the different positions and different times at which the particle and mirror (or barrier-well) are measured, is derived assuming that no interaction occurs between each measurement. Measurement of the particle first, in the correlated interference region, causes a splitting of the mirror (or barrier-well) substate into ones which have and have not reflected the particle. Later measurement of the mirror's (or barrier-well's) position reveals this interference. Synchronous correlated interference is limited spatially and temporally by the two-body wavegroup size and speed. However, the splitting caused by first measuring the particle can prolong the interference of these split mirror (or barrier-well) states. An analog of the Doppler shift in this two-body system is shown to be a consequence of the asynchronous measurement formalism. Coherence transfer and the use of asynchronous correlations to observe macroscopic interference effects in the mirror (or barrier-well), after having reflected a microscopic particle, are also described. This theoretical work, modeling asynchronous measurement in such two-body systems, relies fundamentally on wavefunction collapse.

F. V. Kowalski; R. S. Browne

2014-08-25

212

Heat dissipation sensors of variable length for the measurement of sap flow in trees with deep sapwood  

Microsoft Academic Search

Summary Robust thermal dissipation sensors of variable length (3 to 30 cm) were developed to overcome limitations to the measurement of radial profiles of sap flow in large-diame- ter tropical trees with deep sapwood. The effective measuring length of the custom-made sensors was reduced to 1 cm at the tip of a thermally nonconducting shaft, thereby minimizing the influence of

SHELLEY A. JAMES; MICHAEL J. CLEARWATER; FREDERICK C. MEINZER; GUILLERMO GOLDSTEIN

213

Correlation of Chromosomal Instability, Telomere Length and Telomere Maintenance in Microsatellite Stable Rectal Cancer: A Molecular Subclass of Rectal Cancer  

PubMed Central

Introduction Colorectal cancer (CRC) tumor DNA is characterized by chromosomal damage termed chromosomal instability (CIN) and excessively shortened telomeres. Up to 80% of CRC is microsatellite stable (MSS) and is historically considered to be chromosomally unstable (CIN+). However, tumor phenotyping depicts some MSS CRC with little or no genetic changes, thus being chromosomally stable (CIN-). MSS CIN- tumors have not been assessed for telomere attrition. Experimental Design MSS rectal cancers from patients ?50 years old with Stage II (B2 or higher) or Stage III disease were assessed for CIN, telomere length and telomere maintenance mechanism (telomerase activation [TA]; alternative lengthening of telomeres [ALT]). Relative telomere length was measured by qPCR in somatic epithelial and cancer DNA. TA was measured with the TRAPeze assay, and tumors were evaluated for the presence of C-circles indicative of ALT. p53 mutation status was assessed in all available samples. DNA copy number changes were evaluated with Spectral Genomics aCGH. Results Tumors were classified as chromosomally stable (CIN-) and chromosomally instable (CIN+) by degree of DNA copy number changes. CIN- tumors (35%; n=6) had fewer copy number changes (<17% of their clones with DNA copy number changes) than CIN+ tumors (65%; n=13) which had high levels of copy number changes in 20% to 49% of clones. Telomere lengths were longer in CIN- compared to CIN+ tumors (p=0.0066) and in those in which telomerase was not activated (p=0.004). Tumors exhibiting activation of telomerase had shorter tumor telomeres (p=0.0040); and tended to be CIN+ (p=0.0949). Conclusions MSS rectal cancer appears to represent a heterogeneous group of tumors that may be categorized both on the basis of CIN status and telomere maintenance mechanism. MSS CIN- rectal cancers appear to have longer telomeres than those of MSS CIN+ rectal cancers and to utilize ALT rather than activation of telomerase. PMID:24278232

Boardman, Lisa A.; Johnson, Ruth A.; Viker, Kimberly B.; Hafner, Kari A.; Jenkins, Robert B.; Riegert-Johnson, Douglas L.; Smyrk, Thomas C.; Litzelman, Kristin; Seo, Songwon; Gangnon, Ronald E.; Engelman, Corinne D.; Rider, David N.; Vanderboom, Russell J.; Thibodeau, Stephen N.; Petersen, Gloria M.; Skinner, Halcyon G.

2013-01-01

214

Intra- and inter-observer reliability of combined segmental measurement techniques for predicting immediate post-deployment intraluminal tracheal stent length in dogs.  

PubMed

This study evaluated segmental measurement techniques for predicting immediate post-deployment intraluminal tracheal stent length in dogs with naturally occurring tracheal collapse. Radiographs of 12 client-owned dogs that underwent intraluminal tracheal stent placement were retrospectively reviewed. Tracheal lengths were divided into 1, 2, 3, or 4 equal segments. Stent lengths were predicted using the widest dorsoventral height of each segment, with and without the addition of 10%, and an accompanying foreshortening chart. Techniques were compared for intra- and inter-observer reliability, and post-deployment stent length predictability. There was good to high intra- and inter-observer reliability for all segmental measurements; median intra-class correlation coefficients were 0.98 and 0.92, respectively. Measuring 2 segments without the addition of 10% to the widths was significantly more accurate in predicting immediate post-deployment stent length in terms of percent (P = 0.03) and absolute difference (P = 0.02). Segmental measuring techniques are repeatable amongst observers and may help guide stent selection. PMID:24790228

Monaco, Thomas A; Taylor, Jim A; Langenbach, Anke; Gordon, Sebastian; Vance, Eric

2014-05-01

215

Anthropometric measurements of the forearm and their correlation with the stature of Bengali adult Muslim females.  

PubMed

Stature or body height is one of the most important and useful anthropometric parameter that determine the physical identity of an individual. The study was done to estimate stature from the forearm length on one hundred and fifty Bengali adult Muslim females. This descriptive cross sectional study was done in the department of Anatomy, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh. One hundred and fifty Bengali adult Muslim female was collected from BSMMU & some urban region of Dhaka. Measurement of stature and forearm length of right and left side was taken with a standard anthropometer and a slide caliper respectively. The present study showed significant (p<0.001) positive correlation between the stature and forearm length. PMID:20639830

Laila, S Z; Begum, J A; Ferdousi, R; Parveen, S; Nurunnobi, A M; Yesmin, F

2010-07-01

216

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 and…

Harren, Vincent A.; Kass, Richard A.

217

Comparison between Conventional Blind Embryo Transfer and Embryo Transfer Based on Previously Measured Uterine Length  

PubMed Central

Background Embryo transfer (ET) is one of the most important steps in assisted re- productive technology (ART) cycles and affected by many factors namely the depth of embryo deposition in uterus. In this study, the outcomes of intracytoplasmic sperm injec- tion (ICSI) cycles after blind embryo transfer and embryo transfer based on previously measured uterine length using vaginal ultrasound were compared. Materials and Methods This prospective randomised clinical trial included one hun- dred and forty non-donor fresh embryo transfers during January 2010 to June 2011. In group I, ET was performed using conventional (blind) method at 5-6cm from the external os, and in group II, ET was done at a depth of 1-1.5 cm from the uterine fundus based on previously measured uterine length using vaginal sonography. Appropriate statistical analysis was performed using Student’s t test and Chi-square or Fisher’s exact test. The software that we used was PASW statistics version 18. A p value <0.05 was considered statistically significant. Results Chemical pregnancy rate was 28.7% in group I and 42.1% in group II, while the difference was not statistically significant (p=0.105). Clinical pregnancy, ongoing preg- nancy and implantation rates for group I were 21.2%, 17.7%, and 12.8%, while for group II were 33.9%, 33.9%, and 22.1, respectively. In group I and group II, abortion rates were 34.7% and 0%, respectively, indicating a statistically significant difference (p<0.005). No ectopic pregnancy occurred in two groups. Conclusion The use of uterine length measurement during treatment cycle in order to place embryos at depth of 1-1.5cm from fundus significantly increases clinical and ongo- ing pregnancy and implantation rates, while leads to a decrease in abortion rate (Registra- tion Number: IRCT2014032512494N1). PMID:25379152

Saharkhiz, Nasrin; Nikbakht, Roshan; Salehpour, Saghar

2014-01-01

218

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

219

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

220

Inlet Turbulence and Length Scale Measurements in a Large Scale Transonic Turbine Cascade  

NASA Technical Reports Server (NTRS)

Constant temperature hotwire anemometry data were acquired to determine the inlet turbulence conditions of a transonic turbine blade linear cascade. Flow conditions and angles were investigated that corresponded to the take-off and cruise conditions of the Variable Speed Power Turbine (VSPT) project and to an Energy Efficient Engine (EEE) scaled rotor blade tip section. Mean and turbulent flowfield measurements including intensity, length scale, turbulence decay, and power spectra were determined for high and low turbulence intensity flows at various Reynolds numbers and spanwise locations. The experimental data will be useful for establishing the inlet boundary conditions needed to validate turbulence models in CFD codes.

Thurman, Douglas; Flegel, Ashlie; Giel, Paul

2014-01-01

221

Diffusion length measurement using the scanning electron microscope. [for silicon solar cell  

NASA Technical Reports Server (NTRS)

The present work describes a measuring technique employing the scanning electron microscope in which values of the true bulk diffusion length are obtained. It is shown that surface recombination effects can be eliminated through application of highly doped surface field layers. The effects of high injection level and low-high junction current generation are investigated. Results obtained with this technique are compared to those obtained by a penetrating radiation (X-ray) method, and a close agreement is found. The SEM technique is limited to cells that contain a back surface field layer.

Weizer, V. G.

1975-01-01

222

Time domain measures of inter-channel EEG correlations: a comparison of linear, nonparametric and nonlinear measures.  

PubMed

Correlations between ten-channel EEGs obtained from thirteen healthy adult participants were investigated. Signals were obtained in two behavioral states: eyes open no task and eyes closed no task. Four time domain measures were compared: Pearson product moment correlation, Spearman rank order correlation, Kendall rank order correlation and mutual information. The psychophysiological utility of each measure was assessed by determining its ability to discriminate between conditions. The sensitivity to epoch length was assessed by repeating calculations with 1, 2, 3, …, 8 s epochs. The robustness to noise was assessed by performing calculations with noise corrupted versions of the original signals (SNRs of 0, 5 and 10 dB). Three results were obtained in these calculations. First, mutual information effectively discriminated between states with less data. Pearson, Spearman and Kendall failed to discriminate between states with a 1 s epoch, while a statistically significant separation was obtained with mutual information. Second, at all epoch durations tested, the measure of between-state discrimination was greater for mutual information. Third, discrimination based on mutual information was more robust to noise. The limitations of this study are discussed. Further comparisons should be made with frequency domain measures, with measures constructed with embedded data and with the maximal information coefficient. PMID:24465281

Bonita, J D; Ambolode, L C C; Rosenberg, B M; Cellucci, C J; Watanabe, T A A; Rapp, P E; Albano, A M

2014-02-01

223

Axial length measurement acquisition rates of two optical biometers in cataractous eyes  

PubMed Central

Purpose To compare the ability of two optical biometers to acquire the axial length (AL) measurement in cataractous eyes. Methods This prospective, comparative, single-center study comprised 105 eyes (63 patients). AL was acquired by the composite mean value of 20 measurements (composite-20 IM) and five measurements (composite-5 IM) (IOLMaster® 500 version 7.1 software), and the standard mean value of the first five measurements (standard-5 LS, Lenstar LS 900®). Anterior chamber depth (ACD) and average keratometry (K) readings were acquired. Results AL was acquired in 83.8%, 92.4%, and 84.8% of eyes for the composite-5 IM, composite-20 IM, and standard-5 LS, respectively. Standard-5 LS AL measurements were significantly shorter (P<0.001). IOLMaster® 500-acquired ACD (corneal epithelium to lens) measurements were significantly shorter (P<0.001). IOLMaster® 500 average K measurements were significantly steeper (P<0.001). Conclusion The composite-20 IM had the highest AL acquisition success rate of the three versions evaluated. AL, ACD, and average Ks were statistically different between the two biometers, although the differences were clinically insignificant. PMID:25092960

Epitropoulos, Alice

2014-01-01

224

Diffusion length measurements in bulk and epitaxially grown 3-5 semiconductors using charge collection microscopy  

NASA Technical Reports Server (NTRS)

Diffusion lengths and surface recombination velocities were measured in GaAs diodes and InP finished solar cells. The basic techniques used was charge collection microscopy also known as electron beam induced current (EBIC). The normalized currents and distances from the pn junction were read directly from the calibrated curves obtained while using the line scan mode in an SEM. These values were then equated to integral and infinite series expressions resulting from the solution of the diffusion equation with both extended generation and point generation functions. This expands previous work by examining both thin and thick samples. The surface recombination velocity was either treated as an unknown in a system of two equations, or measured directly using low e(-) beam accelerating voltages. These techniques give accurate results by accounting for the effects of surface recombination and the finite size of the generation volume.

Leon, R. P.

1987-01-01

225

Diffusion length measurement in bulk and epitaxially grown III-V semiconductors using charge collection microscopy  

NASA Technical Reports Server (NTRS)

Diffusion lengths and surface recombination velocities were measured in GaAs diodes and InP finished solar cells. The basic technique used was charge collection microscopy, also known as electron beam induced current (EBIC). The normalized currents and distances from the pn junction were read directly from the calibrated curves obtained while using the line-scan mode in an SEM. These values were then equated to integral and infinite series expressions resulting from the solution of the diffusion equation with both extended-generation and point-generation functions. This expands previous work by examining both thin and thick samples. The surface recombination velocity was either treated as an unknown in a system of two equations or measured directly using low e(-) beam accelerating voltages. These techniques give accurate results by accounting for the effects of surface recombination and the finite size of the generation volume.

Leon, R. P.

1987-01-01

226

Precision measurement of {pi}{pi} scattering lengths at the NA48/2 experiment  

SciTech Connect

The NA48/2 experiment at CERN [1] collected {approx}18{center_dot}10{sup 9} charged kaon decays during the years 2003/4. Along with the primary goals of the collaboration, i.e. the measurement of the CP-violating asymmetry in the K{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup +}{pi}{sup -} and K{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup 0}{pi}{sup 0} decays thanks to the simultaneous collection of K{sup +} and K{sup -} events, the collected data allowed to perform many other interesting analyses. In this paper two independent measurements of {pi}{pi} scattering lengths will be reviewed, using NA48/2 data from the K{sup {+-}}{yields}e{sup {+-}}{nu}{pi}{sup +}{pi}{sup -} decay and from the cusp effect in K{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup +}{pi}{sup -} respectively.

Venditti, Stefano [Universita di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy)

2010-12-28

227

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

228

Two Point Space-Time Correlation of Density Fluctuations Measured in High Velocity Free Jets  

NASA Technical Reports Server (NTRS)

Two-point space-time correlations of air density fluctuations in unheated, fully-expanded free jets at Mach numbers M(sub j) = 0.95, 1.4, and 1.8 were measured using a Rayleigh scattering based diagnostic technique. The molecular scattered light from two small probe volumes of 1.03 mm length was measured for a completely non-intrusive means of determining the turbulent density fluctuations. The time series of density fluctuations were analyzed to estimate the integral length scale L in a moving frame of reference and the convective Mach number M(sub c) at different narrow Strouhal frequency (St) bands. It was observed that M(sub c) and the normalized moving frame length scale L*St/D, where D is the jet diameter, increased with Strouhal frequency before leveling off at the highest resolved frequency. Significant differences were observed between data obtained from the lip shear layer and the centerline of the jet. The wave number frequency transform of the correlation data demonstrated progressive increase in the radiative part of turbulence fluctuations with increasing jet Mach number.

Panda, Jayanta

2006-01-01

229

In vivo measurement of ACL length and relative strain during walking  

PubMed Central

Although numerous studies have addressed the effects of ACL injury and reconstruction on knee joint motion, there is currently little data available describing in vivo ACL strain during activities of daily living. Data describing in vivo ACL strain during activities such as gait is critical to understanding the biomechanical function of the ligament, and ultimately, to improving the surgical treatment of patients with ACL rupture. Thus, our objective was to characterize the relative strain in the ACL during both the stance and swing phases of normal level walking. Eight normal subjects were recruited for this study. Through a combination of magnetic resonance imaging, biplanar fluoroscopy, and motion capture, we created in vivo models of each subject’s normal walking movements to measure knee flexion, ACL length, and relative ACL strain during gait. Regression analysis demonstrated an inverse relationship between knee flexion and ACL length (R2=0.61, p<0.001). Furthermore, relative strain in the ACL peaked at 13±2% (mean± 95%CI) during mid-stance when the knee was near full extension. Additionally, there was a second local maximum of 10±7% near the end of swing phase, just prior to heel strike. These data are a vital step in further comprehending the normal in vivo biomechanics experienced by the ACL. In the future, this information could prove critical to improving ACL reconstruction and provide useful validation to future computational models investigating ACL function. PMID:23178040

Taylor, K A; Cutcliffe, H C; Queen, R M; Utturkar, G M; Spritzer, C E; Garrett, W E; DeFrate, L E

2012-01-01

230

Turbulent transport and length scale measurement experiments with comfined coaxial jets  

NASA Technical Reports Server (NTRS)

A three phase experimental study of mixing downstream of swirling and nonswirling confined coaxial jets was conducted to obtain data for the evaluation and improvement of turbulent transport models currently employed in a variety of computational procedures. The present effort was directed toward the acquisition of length scale and dissipation rate data that provide more accurate inlet boundary conditions for the computational procedures and a data base to evaluate the turbulent transport models in the near jet region where recirculation does not occur, and the acquisition of mass and momentum turbulent transport data for a nonswirling flow condition with a blunt inner jet inlet configuration rather than the tapered inner jet inlet. A measurement technique, generally used to obtain approximate integral length and microscales of turbulence and dissipation rates, was computerized. Results showed the dissipation rate varied by 2 1/2 orders of magnitude across the inlet plane, by 2 orders of magnitude 51 mm from the inlet plane, and by 1 order of magnitude at 102 mm from the inlet plane for a nonswirling flow test conditions.

Johnson, B. V.; Roback, R.

1984-01-01

231

Measuring absolute infrared spectral radiance with correlated photons: new arrangements  

E-print Network

, the measurement of one photon's direction and energy can be used to determine the direction and energy to the nonlinear crystal, so as to overlap with the IR output in direction and spectrum, the down-conversion radiance using correlated photons are presented. The method has the remarkable feature that it allows

Migdall, Alan

232

Measure factors, tension, and correlations of fluid membranes  

Microsoft Academic Search

We study two geometrical factors needed for the correct construction of statistical ensembles of surfaces. Such ensembles appear in the study of fluid bilayer membranes, though our results are more generally applicable. The naive functional measure over height fluctuations must be corrected by these factors in order to give correct, self-consistent formulas for the free energy and correlation functions of

W. Cai; T. C. Lubensky; P. Nelson; T. Powers

1994-01-01

233

PAIN MEDICINE Neural Correlates of Chronic Low Back Pain Measured  

E-print Network

PAIN MEDICINE Neural Correlates of Chronic Low Back Pain Measured by Arterial Spin Labeling Ajay D of the CP exacerba- tions for each back pain subject. Results: The clinically significant worsening.D., Randy L. Gollub, M.D., Ph.D.# ABSTRACT Background: The varying nature of chronic pain (CP) is difficult

Napadow, Vitaly

234

Sonographic measurement of renal size in patients undergoing chronic hemodialysis: Correlation with residual renal function  

PubMed Central

Previous studies have reported that renal size may change when the function is compromised. However, it is not known whether sonographically measured renal size reflects the residual renal function (RRF) in patients undergoing chronic hemodialysis. A total of 140 patients undergoing chronic hemodialysis (?3 months) were investigated in the present study. The patients were divided into two groups according to the daily urine volume: Individuals with RRF (RRF+ group; ?200 ml; n=65) and without RRF (RRF? group; <200 ml; n=75). Renal sizes were measured using sonography and renal volumes were calculated with the ellipsoid formula. Univariable and multivariable stepwise forward logistic regression analyses were performed to examine the correlation between the presence of RRF and various variables. The results indicated that there were statistically significant differences (P<0.001) between the RRF+ and RRF? groups with regard to renal length, width, thickness and volume of the left (length, 7.9±1.2 vs. 6.8±1.2 cm; volume, 60.0±26.7 vs. 40.2±18.1 ml, respectively) and right (length, 7.6±1.2 vs. 6.7±1.2 cm; volume, 50.2±26.5 vs. 33.9±15.3 ml, respectively) sides of the kidney. Multivariable stepwise forward logistic regression analyses showed that the mean renal length or volume and hemodialysis duration were independent predictors of the presence of RRF. Therefore, renal size assessment by ultrasonography may be useful for RRF evaluation in patients undergoing chronic hemodialysis. PMID:24940422

ZHANG, WU-XING; ZHANG, ZHI-MIN; CAO, BING-SHENG; ZHOU, WEI

2014-01-01

235

Contact line extraction and length measurements in model sediments and sedimentary rocks.  

PubMed

The mechanisms that govern the transport of colloids in the unsaturated zone of soils are still poorly understood, because of the complexity of processes that occur at pore scale. These mechanisms are of specific interest in quantifying water quality with respect to pathogen transport (e.g. Escherichia coli, Cryptosporidium) between the source (e.g. farms) and human users. Besides straining in pore throats and constrictions of smaller or equivalent size, the colloids can be retained at the interfaces between air, water, and grains. Theories competing to explain this mechanism claim that retention can be caused by adhesion at the air-water-interface (AWI) between sediment grains or by straining at the air-water-solid (AWS) contact line. Currently, there are no established methods for the estimation of pathogen retention in unsaturated media because of the intricate influence of AWI and AWS on transport and retention. What is known is that the geometric configuration and connectivity of the aqueous phase is an important factor in unsaturated transport. In this work we develop a computational method based on level set functions to identify and quantify the AWS contact line (in general the non-wetting-wetting-solid contact line) in any porous material. This is the first comprehensive report on contact line measurement for fluid configurations from both level-set method based fluid displacement simulation and imaged experiments. The method is applicable to any type of porous system, as long as the detailed pore scale geometry is available. We calculated the contact line length in model sediments (packs of spheres) as well as in real porous media, whose geometry is taken from high-resolution images of glass bead packs and sedimentary rocks. We observed a strong dependence of contact line length on the geometry of the sediment grains and the arrangement of the air and water phases. These measurements can help determine the relative contribution of the AWS line to pathogen retention. PMID:22154497

Rodriguez, Elena; Prodanovi?, Maša; Bryant, Steven L

2012-02-15

236

Length scales and structural dynamics in nematogen pseudonematic domains measured with 2D IR vibrational echoes and optical Kerr effect experiments.  

PubMed

Nematogen liquids in the isotropic phase are macroscopically homogeneous but on multinanometer length scales have pseudonematic domains with correlation lengths that grow as the isotropic to nematic phase transition temperature (TNI) is approached from above. Orientational relaxation of nematogens in the isotropic phase manifests as two fast power laws and a slow exponential decay when measured by optical heterodyne detected optical Kerr effect (OHD-OKE) experiments. The long time exponential relaxation is associated with complete randomization of pseudonematic domains. We examine the effect of local orientational correlation on spectral diffusion (structural evolution) experienced by a vibrational probe molecule within the pseudonematic domains of 4-cyano-4'-pentylbiphenyl (5CB) using two-dimensional infrared (2D IR) vibrational echo spectroscopy. The addition of low concentration 4-pentyl-4'-thiocyanobiphenyl (5SCB) as a long-lived vibrational probe to 5CB is shown to lower TNI of the sample slightly, but the fast power law dynamics and exponential decays observed by OHD-OKE spectroscopy are unchanged. We compare the complete orientational relaxation and spectral diffusion for samples of 5SCB in 5CB to 5SCB in 4-pentylbiphenyl (5B) at four temperatures above TNI. 5B has a molecular structure similar to 5CB but is not a nematogen. At all but the lowest temperature, the spectral diffusion in 5CB and 5B is described well as a triexponential decay with very similar time constants. The results demonstrate that the presence of local orientational order at temperatures well above TNI does not affect the spectral diffusion (structural evolution) within pseudonematic domains when the correlation lengths are short. However, when the temperature of the sample is held very close to TNI, the spectral diffusion in 5CB slows dramatically while that in 5B does not. It is only as the correlation length becomes very long that its presence impacts the spectral diffusion (structural fluctuations) sensed by the vibrational probes located in pseudonematic domains. The orientational relaxation is modeled with schematic mode coupling theory (MCT). Fitting with MCT provides density and orientational correlation functions. The density correlation decays are similar for 5B and 5CB, but the orientational correlation decays are much slower for 5CB. Additionally, the time dependence of the spectral diffusion in 5CB is strikingly similar to that of the density correlation function decay, while the orientational correlation function decay is far too slow to contribute to the spectral diffusion. Therefore, density fluctuations are likely the source of spectral diffusion at temperatures at least 5 K above TNI. PMID:24521155

Sokolowsky, Kathleen P; Bailey, Heather E; Fayer, Michael D

2014-07-17

237

Photocathode rf gun emittance measurements using variable-length laser pulses  

NASA Astrophysics Data System (ADS)

The Gun Test Facility (GTF) at the Stanford Linear Accelerator Center (SLAC) was created to develop an appropriate injector for the proposed Linac Coherent Light Source (LCLS) at SLAC. The LCLS design requires the injector to produce a beam with at least 1 nC of charge in a 10 ps or shorter pulse with no greater than 1 (pi) mm-mrad normalized rms emittance. The first photoinjector under study at the GTF is a 1.6 cell S-band symmetrized gun with an emittance compensation solenoid. Emittance measurements, reported here, were made as function of the transverse laser pulse shape and the Gaussian longitudinal laser pulse length. The lowest achieved emittance to data with 1 nC of charge is 5.6 (pi) mm-mrad and was obtained with both a Gaussian longitudinal and transverse pulse shape with 5 ps FWHM and 2.4 mm FWHM respectively. The measurement is in agreement with a PARMELA simulation using measured beam parameters. There are indications that the accelerator settings used in the results presented here were not optimal. Simulations indicate that a normalized emittance meeting the LCLS requirement can be obtained using appropriately shaped transverse and temporal laser/electron beam pulses. Work has begun on producing temporal flat top laser pulses which combined with transverse clipping of the laser is expected to lower the emittance to approximately 1 (pi) mm-mrad for 1 nC beams with optimal accelerator settings.

Schmerge, John F.; Hernandez, Mike; Hogan, Mark J.; Reis, David A.; Winick, Herman

1999-07-01

238

Extension of traceable calibration for electronic distance measuring instruments beyond the length of the laboratory  

NASA Astrophysics Data System (ADS)

Electronic distance measuring instruments (EDMs) are devices used by surveyors where calibrated tape measures are not adequate or appropriate. Modern EDMs are generally accurate and reliable, are commonly capable of measuring up to 6 km, and may be combined with an electronic theodolite in a total station unit. Precise traceable calibration of EDMs is possible using a linear displacement interferometer, for example, with the respective reflectors in back-to-back configuration. Calibration data may be analysed for scale error and cyclical error. The distances so calibrated are usually constrained by the length of laboratory (and/or straight rails) available, as well as by the maximum working distance of the interferometer, but may be extended further with caution by the introduction of mirrors to fold the EDM beam. This paper describes the apparatus used to calibrate an EDM up to 200 m in a 60 m laboratory, and investigates some of the problems and artefacts that can arise, for example, from unwanted intermediate reflections of the EDM beam.

Forde, Lucy C.; Howick, Eleanor F.

2003-11-01

239

Soft defect printability: correlation to optical flux-area measurements  

NASA Astrophysics Data System (ADS)

Soft defects on photomasks have, historically, been difficult to measure, and predict how the measured size of a soft defect will correlate to what prints, if at all. Over the past few years KLA-Tencor STARlight surface inspection has become the inspection of choice for soft defects. Though the capture rate of this tool is exceptional, the defect sizing capability has lacked in accuracy. Customer specifications have traditionally been built around defect size and transmission. If a given defect cannot be accurately sized then it cannot be accurately dispositioned. In this study we are attempting to show a correlation between the AVI defect measurement tool sizing and what actually prints on the wafer. We will show defect sizing both from the KLA-Tencor STARlight and pattern tools, the AVI tool, AIMS and VSS printability data.

Taylor, Darren; Fiekowsky, Peter

2001-01-01

240

Measurement of electrostriction in bone using digital image correlation  

NASA Astrophysics Data System (ADS)

The electromechanical properties of bone may play roles in the growth of bone tissue. The electrostriction effect of bone, which is one of the electromechanical properties of bone, was investigated using the digital image correlation technique (DIC). The advantage of using DIC is that the light beam used for the displacement measurement does not interfere with the electric field exerted on the bone specimen. To measure the bending deflections of a bone cantilever in an electric field, the displacement of the free end surface of the cantilever was measured using the image correlation technique. The experimental results show that the bending direction of the bone cantilevers is independent of the electric field direction and that the bending deflections are proportional to the square of the applied voltages. The attractive force between the charges on the electrode and the unlike charges in the specimen can be equivalent to a uniform distribution load regardless of the thickness of the bone specimen.

Xu, Lianyun; Hou, Zhende; Fu, Donghui; Yang, Lei; Yi, Weitian; Kang, Huimin

2015-02-01

241

Accuracy of axial length measurements from immersion B-scan ultrasonography in highly myopic eyes  

PubMed Central

AIM To evaluate the accuracy of axial length (AL) measurements obtained from immersion B-scan ultrasonography (immersion B-scan) for intraocular lens (IOL) power calculation in patients with high myopia and cataracts. METHODS Immersion B-scan, contact A-scan ultrasonography (contact A-scan), and the IOLMaster were used to preoperatively measure the AL in 102 eyes from 102 patients who underwent phacoemulsification and IOL implantation. Patients were divided into two groups according to the AL: one containing patients with 22 mm?AL<26 mm(group A) and the other containing patients with AL?26 mm (group B). The mean error (ME) was calculated from the difference between the AL measurement methods predicted refractive error and the actual postoperative refractive error. RESULTS In group A, ALs measured by immersion B-scan (23.48±1.15) didn't differ significantly from those measured by the IOLMaster (23.52±1.17) or from those by contact A-scan (23.38±1.20). In the same group, the standard deviation (SD) of the mean error (ME) of immersion B-scan (-0.090±0.397 D) didn't differ significantly from those of IOLMaster (-0.095±0.411 D) and contact A-scan (-0.099±0.425 D). In group B, ALs measured by immersion B-scan (27.97±2.21 mm) didn't differ significantly from those of the IOLMaster (27.86±2.18 mm), but longer than those measured by Contact A-scan (27.75±2.23 mm, P=0.009). In the same group, the standard deviation (SD) of the mean error (ME) of immersion B-scan (-0.635±0.157 D) didn't differ significantly from those of the IOLMaster (-0.679±0.359 D), but differed significantly from those of contact A-scan (-0.953±1.713 D, P=0.028). CONCLUSION Immersion B-scan exhibits measurement accuracy comparable to that of the IOLMaster, and is thus a good alternative in measuring AL in eyes with high myopia when the IOLMaster can't be used, and it is more accurate than the contact A-scan. PMID:24967188

Yang, Qing-Hua; Chen, Bing; Peng, Guang-Hua; Li, Zhao-Hui; Huang, Yi-Fei

2014-01-01

242

Magnetic correlation length for undoped and lightly doped La[sub 2]CuO[sub 4[minus][ital y  

SciTech Connect

We have used a self-consistent Green's function theory based on the quasi-two-dimensional Heisenberg model to explain the magnetic correlation length for both undoped and lightly doped samples of La[sub 2]CuO[sub 4[minus][ital y

Singh, R.P.; Singh, M. (Department of Physics, The University of Western Ontario, London, Ontario, N6A 3K7 (Canada))

1995-03-01

243

Magnetization and correlation length of the easy-plane ferromagnetic chain: Numerical analysis and application to (C6H11NH3)CuBr3  

NASA Astrophysics Data System (ADS)

The ferromagnetic spin-(1/2 one-dimensional XXZ Heisenberg model is studied numerically by quantum Monte Carlo analysis and extrapolations in 1/N of finite-size chain data. Reliable magnetization and correlation-length estimates are presented and a quantitative agreement with recent experimental data on the compound (C6H11NH3)CuBr3 is found.

Kamieniarz, G.; Mallezie, F.; Dekeyser, R.

1988-10-01

244

Magnification-Temperature Correlation: the Dark Side of ISW Measurements  

E-print Network

Integrated Sachs-Wolfe (ISW) measurements, which involve cross-correlating the CMB with the foreground large-scale structure (e.g. galaxies/quasars), have proven to be an interesting probe of dark energy. We show that magnification bias, which is the inevitable modulation of the foreground number counts by gravitational lensing, alters both the shape and amplitude of the observed ISW signal. This is true especially at high redshifts because (1) the intrinsic galaxy-temperature signal diminishes greatly back in the matter dominated era, (2) the lensing efficiency increases with redshift and (3) the number count slope generally steepens with redshift in a magnitude limited sample. At z >~ 2, the magnification-temperature correlation dominates over the intrinsic galaxy-temperature correlation and causes the observed ISW signal to increase with z, despite dark energy subdominance -- a result of the fact that magnification probes structures between the observer and the sources. Ignoring magnification bias can then...

LoVerde, M; Gaztañaga, E; Verde, Marilena Lo; Hui, Lam; Gaztanaga, Enrique

2006-01-01

245

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

246

Viscoelastic properties of normal and infarcted myocardium measured by a multifrequency shear wave method: comparison with pressure-segment length method.  

PubMed

Our aims were (i) to compare in vivo measurements of myocardial elasticity by shear wave dispersion ultrasound vibrometry (SDUV) with those by the conventional pressure-segment length method, and (ii) to quantify changes in myocardial viscoelasticity during systole and diastole after reperfused acute myocardial infarction. The shear elastic modulus (?1) and viscous coefficient (?2) of left ventricular myocardium were measured by SDUV in 10 pigs. Young's elastic modulus was independently measured by the pressure-segment length method. Measurements made with the SDUV and pressure-segment length methods were strongly correlated. At reperfusion, ?1 and ?2 in end-diastole were increased. Less consistent changes were found during systole. In all animals, ?1 increased linearly with left ventricular pressure developed during systole. Preliminary results suggest that ?1 is preload dependent. This is the first study to validate in vivo measurements of myocardial elasticity by a shear wave method. In this animal model, the alterations in myocardial viscoelasticity after a myocardial infarction were most consistently detected during diastole. PMID:24814645

Pislaru, Cristina; Urban, Matthew W; Pislaru, Sorin V; Kinnick, Randall R; Greenleaf, James F

2014-08-01

247

Improved extended digital image correlation for crack tip deformation measurement  

NASA Astrophysics Data System (ADS)

The objective is to find an appropriate shape function which can enhance the performance of Extended Digital Image Correlation (X-DIC). This paper presents an improved X-DIC methodology to measure the discontinuous deformation across the crack. After simplifying the shape function of crack tip element based on the linear elastic fracture mechanics, non-rectangular subset is proposed to eliminate the effect of the crack width on the measurement accuracy. Then, the work verifies the performance of improved X-DIC by measuring the deformation of a specimen with a mode I crack. Experimental results show that the proposed method is effective at improving the measurement accuracy and enhancing the computational efficiency of X-DIC. In the end, the thesis provides a practical application of improved X-DIC to crack tip deformation measurement.

Chen, Jinlong; Zhan, Nan; Zhang, Xiaochuan; Wang, Jixiao

2015-02-01

248

Measuring Dark Energy Clustering with CMB-Galaxy Correlations  

E-print Network

The integrated Sachs-Wolfe (ISW) effect in the cosmic microwave background (CMB) as measured through its correlation with galaxies provides a unique opportunity to study the dynamics of the dark energy through its large scale clustering properties. Ultimately, a deep all-sky galaxy survey out to z~2 can make a 10sigma or ~10% measurement of the correlation and limit ~3% changes in the gravitational potential or total density fluctuation due to dark energy clustering on the Gpc scale. A canonical single scalar field or quintessence model predicts that these clustering effects will appear on the horizon scale with a strength that reflects the evolution of the dark energy density. In terms of a constant equation of state, this would allow tests of the quintessence prediction for models where |1+w| > 0.05.

Wayne Hu; Ryan Scranton

2004-12-01

249

Measurement and correlation of jet fuel viscosities at low temperatures  

NASA Technical Reports Server (NTRS)

Apparatus and procedures were developed to measure jet fuel viscosity for eight current and future jet fuels at temperatures from ambient to near -60 C by shear viscometry. Viscosity data showed good reproducibility even at temperatures a few degrees below the measured freezing point. The viscosity-temperature relationship could be correlated by two linear segments when plotted as a standard log-log type representation (ASTM D 341). At high temperatures, the viscosity-temperature slope is low. At low temperatures, where wax precipitation is significant, the slope is higher. The breakpoint between temperature regions is the filter flow temperature, a fuel characteristic approximated by the freezing point. A generalization of the representation for the eight experimental fuels provided a predictive correlation for low-temperature viscosity, considered sufficiently accurate for many design or performance calculations.

Schruben, D. L.

1985-01-01

250

A quantitative measure of phase correlations in density fields  

NASA Technical Reports Server (NTRS)

A quantitative measure of the phase correlations in a density field is presented based on the location of the maxima of the Fourier components of that field. It is found that this measue can easily detect non-Gaussian behavior either in artificially constructed density fields or those that become non-Gaussian from gravitational clustering of Gaussian initial conditions. It is found that different initial power spectra produce somewhat distinguishable signals, and the signals are robust against sparse sampling.

Scherrer, Robert J.; Melott, Adrian L.; Shandarin, Sergei F.

1991-01-01

251

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

252

Measuring short electron bunch lengths using coherent Smith-Purcell radiation  

DOEpatents

A method is provided for directly determining the length of sub-picosecond electron bunches. A metallic grating is formed with a groove spacing greater than a length expected for the electron bunches. The electron bunches are passed over the metallic grating to generate coherent and incoherent Smith-Purcell radiation. The angular distribution of the coherent Smith-Purcell radiation is then mapped to directly deduce the length of the electron bunches. 8 figs.

Nguyen, D.C.

1999-03-30

253

Measurement of ultraviolet radiation and correlation to direct normal irradiance  

SciTech Connect

The DLR operates a solar furnace at the site near Cologne for experiments in material research and solar chemistry. For these activities that make use of concentrating systems the direct normal irradiances are of main importance. Especially for the photochemistry the shorter wavelengths in the visible part of the solar spectrum and the ultraviolet region are important. for collecting operational data, for statistical purpose, and for measuring the solar furnace input power the DLR operates also a meteorological station that besides temperature, rain, and wind data records several important irradiance parameters like direct normal or direct normal narrowband UVA and UVB. In order to compare measured data to model predictions the authors performed a correlation analysis between LOWTRAN results and direct normal irradiance and measurements of UVA at 368 nm and UVB at 306 nm. It shows that on clear summer days and high direct normal irradiances of about 800 W/m{sup 2} the model data agree well with the UVA measurements. In the UVB the deviation is larger. On sunny days with thin cloud coverage the data show more scattering and higher UV intensities compared to the model at similar elevation angles. Empirical correlation functions are proposed for modeling the UVA and UVB measurements.

Neumann, A.

1999-07-01

254

A Nonlocal Strain Measure for Digital Image Correlation  

E-print Network

We propose a nonlocal strain measure for use with digital image correlation (DIC). Whereas the traditional notion of compatibility (strain as the derivative of the displacement field) is problematic when the displacement field varies substantially either because of measurement noise or material irregularity, the proposed measure remains robust, well-defined and invariant under rigid body motion. Moreover, when the displacement field is smooth, the classical and nonlocal strain are in agreement. We demonstrate, via several numerical examples, the potential of this new strain measure for problems with steep gradients. We also show how the nonlocal strain provides an intrinsic mechanism for filtering high frequency content from the strain profile and so has a high signal to noise ratio. This is a convenient feature considering image noise and its impact on strain calculations.

Lehoucq, R B; Turner, D Z

2014-01-01

255

INTRAFAMILIAL AND MIDPARENTAL-CHILD CORRELATIONS AND HERITABILITY ESTIMATES OF ANTHROPOMETRIC MEASUREMENTS IN PRADER-WILLI SYNDROME FAMILIES  

PubMed Central

To determine the effects of familial background on anthropometric dimensions in Prader-Willi syndrome (PWS), we measured weight; height; sitting height; longitude and breadth of the head, hands, and feet; head, arm, and calf circumferences; and triceps and subscapular skinfolds in 28 individuals with the syndrome and their natural parents. Midparental-child correlations were significant for height and foot length, with heritability estimates of 0.52 and 0.68, respectively. Significant mother-child correlations were found for weight, height, foot length, and minimal frontal diameter for the total group; in addition, hand length and breadth, and calf and arm circumferences were significant for the patients age 12.5 years or under. These data provide evidence for maternal effects on several physical characteristics in PWS, particularly in younger patients. PMID:25505360

Butler, Merlin G.; Haynes, Judy L.; Meaney, F. John

2014-01-01

256

Magnification-Temperature Correlation: the Dark Side of ISW Measurements  

E-print Network

Integrated Sachs-Wolfe (ISW) measurements, which involve cross-correlating the CMB with the foreground large-scale structure (e.g. galaxies/quasars), have proven to be an interesting probe of dark energy. We show that magnification bias, which is the inevitable modulation of the foreground number counts by gravitational lensing, alters both the shape and amplitude of the observed ISW signal. This is true especially at high redshifts because (1) the intrinsic galaxy-temperature signal diminishes greatly back in the matter dominated era, (2) the lensing efficiency increases with redshift and (3) the number count slope generally steepens with redshift in a magnitude limited sample. At z >~ 2, the magnification-temperature correlation dominates over the intrinsic galaxy-temperature correlation and causes the observed ISW signal to increase with z, despite dark energy subdominance -- a result of the fact that magnification probes structures between the observer and the sources. Ignoring magnification bias can then lead to erroneous conclusions about dark energy. While the lensing modulation opens up an interesting high z window for ISW measurements, high z measurements are not expected to add much new information to low z ones if dark energy is the cosmological constant. This is because lensing introduces significant covariance across redshifts. The most compelling reason to pursue high z ISW measurements is to look for a potential surprise such as early dark energy domination or the signature of modified gravity. We conclude with a discussion of existing measurements, the highest z of which is at the margin of being sensitive to magnification bias. We also develop a formalism which might be of general interest: to predict biases in estimating parameters when certain physical effects are ignored in interpreting data.

Marilena LoVerde; Lam Hui; Enrique Gaztanaga

2007-01-30

257

Length Conversions and Length-Weight Relations for Pallid Sturgeon  

Microsoft Academic Search

We developed conversion formulas for standard length to fork length, fork length to total length, and standard length to total length for 30 pallid sturgeons Scaphirhynchus albus from the upper Missouri River. Formulas for converting length to weight were also developed for each of the length measurements. We add our length and weight data on 30 specimens of this rare

K. D. Keenlyne; S. J. Maxwell

1993-01-01

258

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

2013-01-01

259

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

260

Measuring capital market efficiency: Global and local correlations structure  

NASA Astrophysics Data System (ADS)

We introduce a new measure for capital market efficiency. The measure takes into consideration the correlation structure of the returns (long-term and short-term memory) and local herding behavior (fractal dimension). The efficiency measure is taken as a distance from an ideal efficient market situation. The proposed methodology is applied to a portfolio of 41 stock indices. We find that the Japanese NIKKEI is the most efficient market. From a geographical point of view, the more efficient markets are dominated by the European stock indices and the less efficient markets cover mainly Latin America, Asia and Oceania. The inefficiency is mainly driven by a local herding, i.e. a low fractal dimension.

Kristoufek, Ladislav; Vosvrda, Miloslav

2013-01-01

261

High-pT direct photon azimuthal correlation measurements  

NASA Astrophysics Data System (ADS)

The azimuthal correlations of direct photons (?dir) with high transverse momentum (pT), produced at mid-rapidity (|? ?dir | < 1) in Au + Au collisions at center-of-mass energy ?{sNN} = 200GeV, are measured and compared to those of neutral pions (?0) in the same kinematic range. The measured azimuthal elliptic anisotropy of direct photon, v2?dir(pT), at high pT (8 measured kinematic range 12

Hamed, Ahmed M.

2014-11-01

262

Displacement measurements of highway bridges using digital image correlation methods  

NASA Astrophysics Data System (ADS)

Digital image correlation methods (DICMs) are important tools in experimental solid mechanics. DICM is becoming very versatile and cost effective due to the dramatic improvement over the digital cameras. Current study applies DICMs to displacement measurements of full-scale concrete beams. Computer programs are implemented and tested against the contact measurements using a linear variable differential transformer (LVDT). The calculated displacements agree with the LVDT measurements that the difference is mostly within 3%. The DICM programs produce similar displacement fields to those obtained using two computer codes written by other researchers. The DICM programs compute a singlepoint in merely seconds while completing the displacement calculation for a whole-field region of one mega pixels in one hour. Additional tests on the vertical displacement of a highway bridge also achieve a reasonable result which can be extended to health monitoring of bridges.

Chiang, Chih-Hung; Shih, Ming-Hsiang; Chen, Welltin; Yu, Chih-Peng

2011-12-01

263

Optimal design of optical length in low turbidity measurement system with wavelength 1310 nm and 1550 nm  

NASA Astrophysics Data System (ADS)

To meet the need of long distance transmission in low turbidity measurement system for low-loss, a new optical structure with wavelength 1310nm and 1550nm as the incident light is employed. In this research, experiments have been done for different optical length of the two wavelength light sources. The results show that: first, the transmitted light intensity has big difference under the circumstance of same concentration and optical length, though the loss has no remarkable difference transmitted in optical fiber between 1310nm and 1550nm. Second, the optimized optical length for better absorbance has been determined for 1310nm and 1550nm and it is irrelevant to the incident intensity. Third, the intensity of the two transmitted light decreases exponentially with the increase of optical length. For example, when the range of the optical length of 1310nm is 0.5mm-2mm, the transmitted intensity is about 60%-79% and the absorbance is 0.12-0.42. The transmitted intensity is about 5%-44%. When the range of the optical length of 1550nm is 0.5mm-2mm and the absorbance is still 0.12-0.42. Our experimental data provides the basis both for the optical length selection of these two light sources in water and the near-infrared spectral wavelength selection.

Cao, Hui-bin; Liu, Jian-guo; Gui, Hua-qiao; Wang, Jie; Wang, Huan-qin

2014-11-01

264

Correlated speckle noise in white-light interferometry: theoretical analysis of measurement uncertainty  

SciTech Connect

The partial coherent illumination of the specimen, which is required for white-light interferometric measurements of optically rough surfaces, directly leads to speckle. The electric field of such speckle patterns strongly fluctuates in amplitude and phase. This spatially correlated noise influences the accuracy of the measuring device. Although a variety of noise sources in white-light interferometry has been studied in recent years, they do not account for spatial correlation and, hence, they cannot be applied to speckle noise. Thus, we derive a new model enabling quantitative predictions for measurement uncertainty caused by speckle. The model reveals that the accuracy can be attributed mainly to the degree of spatial correlation, i.e., the average size of a speckle, and to the coherence length of the light source. The same parameters define the signal-to-noise ratio in the spectral domain. The model helps to design filter functions that are perfectly adapted to the noise characteristics of the respective device, thus improving the accuracy of postprocessing algorithms for envelope detection. The derived expressions are also compared to numerical simulations and experimental data of two different types of interferometers. These results are a first validation of the theoretical considerations of this article.

Hering, Marco; Koerner, Klaus; Jaehne, Bernd

2009-01-20

265

Correlates of objectively measured physical activity in cardiac patients  

PubMed Central

Cardiac patients would benefit from increasing their physical activity (PA) levels. Understanding of factors that influence cardiac patients’ PA participation would benefit the development of effective interventions. Therefore, the purpose of this study was to determine correlates of objectively-measured PA in cardiac patients. Participants were 65 cardiac patients (74% male, 95% white), age 58.6±10.6 years. The amount of time spent in PA was measured by ActiGraph GT3X accelerometers for 7 days prior to joining cardiac rehabilitation programs (CRP). A total of 25 potential determinants of PA across multiple domains (demographic, clinical, psychosocial, and behavioral) were measured via self-reported questionnaire and clinical examinations. Backward elimination model selection procedures were performed to examine associations of potential determinants with total PA (min/day) and moderate-to-vigorous PA (MVPA) (min/day). Patients spent 153.8±62.8 and 8.4±8.1 min/day in total PA and MVPA, respectively. Across four domains, ten and five potential correlates were found to be significant in univariate analyses for MVPA and total PA, respectively. In the final model, functional capacity, PA readiness, and participation in regular exercise were positively associated with MVPA (R2 =26.6%). Functional capacity and PA readiness were also positively associated with total PA (R2 =15.9%). Future initiatives to increase PA levels in cardiac patients could be improved by considering patients’ functional capacity, PA readiness, and exercise history in designing interventions. PMID:25414828

Ozemek, Cemal; Riggin, Katrina; Strath, Scott; Kaminsky, Leonard

2014-01-01

266

Integrated measurements of acoustical and optical thin layers II: Horizontal length scales  

E-print Network

Polytechnic State University, San Luis Obispo, CA 93407, USA b College of Oceanic and Atmospheric Sciences-optics Bioacoustics Bioluminescence Length scales Autocorrelation a b s t r a c t The degree of layered organization

Benoit-Bird, Kelly J.

267

High-resolution, large dynamic range fiber length measurement based on frequency-shifted asymmetrical Sagnac interferometer  

E-print Network

We propose and experimentally demonstrate a single-mode fiber length and dispersion measurement system based on a novel frequency-shifted asymmetric Sagnac interferometer incorporating an acousto-optic modulator (AOM). By sweeping the driving frequency of the AOM, which is asymmetrically placed in the Sagnac loop, the optical length of the fiber can be determined by measuring the corresponding variation in the phase delay between the two counter-propagating light beams. Combined with a high-resolution data processing algorithm, this system yields a dynamic range from a few centimeters to 60km (limited only by our availability of long fibers) with a resolution about 1ppm for long fibers.

Bing Qi; Andrew Tausz; Li Qian; Hoi-Kwong Lo

2006-07-22

268

Automatic difference measure between movies using dissimilarity measure fusion and rank correlation coefficients  

E-print Network

Automatic difference measure between movies using dissimilarity measure fusion and rank correlation dissimilarities. Subjective tests with human observers on the CITIA animation movie database have been carried out. In this paper, we work with the dataset used by Benoit & al. in [2]. It is composed of short animated movies

Paris-Sud XI, Université de

269

Some measurements of time and space correlation in wind tunnel  

NASA Technical Reports Server (NTRS)

Results are presented of research obtained by means of an apparatus for measurement of time and space correlation and of a spectral analyzer in the study of the longitudinal component of turbulence velocities in a wind tunnel downstream of a grid of meshes. Application to the case of a flat-plate boundary layer is illustrated. These researches were made at the Laboratoire de Mecanique de l'Atmosphere de l'I.M.F.M. for the O.N.E.R.A.

Favre, A; Gaviglio, J; Dumas, R

1955-01-01

270

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

271

Correlation of macroscopic ion dynamics with microscopic length scale and modification of network structure in ion conducting mixed network former glasses  

NASA Astrophysics Data System (ADS)

We have studied silver ion dynamics in mixed network former molybdophosphate glasses by varying the glass network formers ratio. We have shown that the macroscopic ion transport is correlated to the characteristic microscopic length scale and the modification of the phosphate network structure due to the introduction of molybdate network former. The time-temperature superposition of the conductivity spectra onto a single master curve is independent of the mixing of the network formers.

Deb, B.; Ghosh, A.

2012-01-01

272

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. PMID:23832294

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

2013-11-01

273

Correlates of objectively measured physical activity in dogs.  

PubMed

To increase physical activity (PA) levels in dogs and to better evaluate their energy requirements, there is a need to understand which factors or correlates are associated with PA and/or sedentary behaviour. Improving our understanding of these correlates also has implications for prescribed energy requirements in dogs. PA was measured using accelerometry in 62 dogs from two common breeds (Labrador retrievers and Cocker spaniels). Five potential correlates (age, sex, breed, neuter status, body condition score) were tested for associations with total volume of PA, light-moderate intensity PA, vigorous intensity PA and sedentary behaviour. Age and breed were associated with total volume of PA, light-moderate intensity PA and sedentary behaviour in the final models. Age was associated with vigorous intensity PA. The final models explained 60%, 40%, 63% and 44% of variance in total volume of PA, light-moderate intensity PA, vigorous intensity PA and sedentary behaviour, respectively. These results should improve understanding of the variation in energy requirements of dogs, as well as the development of age and breed-specific diets and the prevention and treatment of canine obesity. PMID:24378292

Morrison, Ryan; Penpraze, Victoria; Greening, Ruth; Underwood, Tom; Reilly, John J; Yam, Philippa S

2014-02-01

274

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

275

Correlation between the Length Reduction of Carbon Nanotubes and the Electrical Percolation Threshold of Melt Compounded Polyolefin Composites.  

PubMed

The objectives of this work are to quantify the degree of multiwalled carbon nanotube (MWCNT) length reduction upon melt compounding and to demonstrate unambiguously that the length reduction is mainly responsible for the increase in electrical percolation threshold of the resulting composites. Polyolefin matrices of varying viscosities and different functional groups are melt compounded with MWCNTs. A simple method is developed to solubilize the polymer matrix and isolate the MWCNTs, enabling detailed imaging analysis. In spite of the perceived strength of the MWCNTs, the results demonstrate that the shear forces developed during melt mixing are sufficient to cause significant nanotube breakage and length reduction. Breakage is promoted when higher MWCNT contents are used, due to increased probability of particle collisions. Furthermore, the higher shear forces transmitted to the nanotubes in the presence of higher matrix viscosities and functional groups that promote interfacial interactions, shift the nanotube distribution toward smaller sizes. The length reduction of the MWCNTs causes significant increases in the percolation threshold, due to the loss of interconnectivity, which results in fewer conductive pathways. These findings are validated by comparing the experimental percolation threshold values with those predicted by the improved interparticle distance theoretical model. PMID:25548884

Vasileiou, Alexandros A; Kontopoulou, Marianna; Gui, Hua; Docoslis, Aristides

2015-01-28

276

Accurate measurement of curvilinear shapes by Virtual Image Correlation  

NASA Astrophysics Data System (ADS)

The proposed method allows the detection and the measurement, in the sense of metrology, of smooth elongated curvilinear shapes. Such measurements are required in many fields of physics, for example: mechanical engineering, biology or medicine (deflection of beams, fibers or filaments), fluid mechanics or chemistry (detection of fronts). Contrary to actual methods, the result is given in an analytical form of class C? (and not a finite set of locations or pixels) thus curvatures and slopes, often of great interest in science, are given with good confidence. The proposed Virtual Image Correlation (VIC) method uses a virtual beam, an image which consists in a lateral expansion of the curve with a bell-shaped gray level. This figure is deformed until it fits the best the physical image with a method issued from the Digital Image Correlation method in use in solid mechanics. The precision of the identification is studied in a benchmark and successfully compared to two state-of-the-art methods. Three practical examples are given: a bar bending under its own weight, a thin fiber transported by a flow within a fracture and a thermal front. The first allows a comparison with theoretical solution, the second shows the ability of the method to deal with complex shapes and crossings and the third deals with ill-defined image.

Semin, B.; Auradou, H.; François, M. L. M.

2011-10-01

277

Correlated responses to long-term selection for clutch length in dwarf brown-egg layers carrying or not carrying the naked neck gene.  

PubMed

Two dwarf brown-egg layer lines, differing in their genotype for the naked neck gene (NA), line L2 (NA*NA/*NA) and line L1 (NA*N/*N), have been selected for 16 generations for increased average clutch length. A control line from the same base population, dwarf and segregating for the NA gene, was maintained by random mating. Genetic parameters were estimated by a multivariate derivative-free restricted maximum likelihood procedure, and the NA gene effect was estimated within the unselected control line. The studied traits included clutch traits, egg production traits, abnormal eggs, egg weight at 36 wk, and BW at 42 wk. The average clutch length, egg number, and maximum clutch length were normalized using the Box-Cox transformation. In response to 16 generations of direct selection for increased average clutch length, other egg production traits, such as laying rate and total egg number, have been indirectly improved in a dwarf layer genetic background. The estimated heritabilities were 0.406 to 0.424 for transformed average clutch length (TCL), 0.373 to 0.411 for transformed egg number (TEN), 0.529 to 0.559 for age at first egg (AFE), 0.275 to 0.282 for laying rate (LR), 0.455 for dutch number (CN), and 0.319 for the number of double-yolked eggs (DYEN). The TCL had high genetic correlations with TEN (0.777), LR (0.863), maximum clutch length (0.902), and CN (-0.845). Selection for increased average clutch length was an effective method for increasing egg production. Line L2 showed a higher egg weight than L1, which indicates that the combined effect of NA and DW genes was favorable to maintain egg weight when egg number could be improved. Line L1 showed a higher number of DYEN, suggesting that the regulation of follicular maturation was changed in this line. PMID:12762391

Chen, C F; Tixier-Boichard, M

2003-05-01

278

Measurement of cranial optical path length as a function of age using phase resolved near infrared spectroscopy.  

PubMed

Near infrared spectroscopy (NIRS) has been used to measure concentration changes of cerebral hemoglobin and cytochrome in neonates, children, and adults, to study cerebral oxygenation and hemodynamics. To derive quantitative concentration changes from measurements of light attenuation, the optical path length must be known. This is obtained by multiplying the source/ detector separation by a laboratory measured differential path length factor (DPF) which accounts for the increased distance traveled by light due to scattering. DPF has been measured by time of flight techniques on small populations of adults and postmortem infants. The values for adults are greater than those for newborns, and it is not clear how to interpolate the present data for studies on children. Recent developments in instrumentation using phase resolved spectroscopy techniques have produced a bedside unit which can measure optical path length on any subject. We have developed an intensity modulated optical spectrometer which measures path length at four wavelengths. Two hundred and eighty three subjects from 1 d of age to 50 y were studied. Measurements were made at a fixed frequency of 200 MHz and a source detector separation of 4.5 cm. Results suggest a slowly varying age dependence of DPF, following the relation DPF690 = 5.38 + 0.049A0.877, DPF744 = 5.11 + 0.106A0.723, DPF807 = 4.99 + 0.067A0.814, and DPF832 = 4.67 + 0.062A0.819, where DPF690 is the DPF measured at 690 nm and A is age is expressed in years from full term. There was a wide scatter of values, however, implying that ideally DPF should be measured at the time of each study. PMID:8726247

Duncan, A; Meek, J H; Clemence, M; Elwell, C E; Fallon, P; Tyszczuk, L; Cope, M; Delpy, D T

1996-05-01

279

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

Microsoft Academic Search

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

Vernon Thomas Bechel

1997-01-01

280

A Correlational and Factor Analytic Study of Four Questionnaire Measures of Organizational Culture  

Microsoft Academic Search

A review of the literature revealed four major self-report measures of organizational culture measuring organizational behavioral norms or values. This study set out to compare these different measures by correlational and factor analysis. The results of the correlational analysis showed the convergent validity of the questionnaires in a number of significant correlations among the overlapping subscales intended to measure the

Athena Xenikou; Adrian Furnham

1996-01-01

281

Time Resolved Correlation measurements of temporally heterogeneous dynamics  

E-print Network

Time Resolved Correlation (TRC) is a recently introduced light scattering technique that allows to detect and quantify dynamic heterogeneities. The technique is based on the analysis of the temporal evolution of the speckle pattern generated by the light scattered by a sample, which is quantified by $c\\_I(t,\\tau)$, the degree of correlation between speckle images recorded at time $t$ and $t+\\tau$. Heterogeneous dynamics results in significant fluctuations of $c\\_I(t,\\tau)$ with time $t$. We describe how to optimize TRC measurements and how to detect and avoid possible artifacts. The statistical properties of the fluctuations of $c\\_I$ are analyzed by studying their variance, probability distribution function, and time autocorrelation function. We show that these quantities are affected by a noise contribution due to the finite number $N$ of detected speckles. We propose and demonstrate a method to correct for the noise contribution, based on a $N\\to \\infty$ extrapolation scheme. Examples from both homogeneous and heterogeneous dynamics are provided. Connections with recent numerical and analytical works on heterogeneous glassy dynamics are briefly discussed.

Agnes Duri; Hugo Bissig; Veronique Trappe; Luca Cipelletti

2005-08-01

282

Nanomechanical measurement of astrocyte stiffness correlated with cytoskeletal maturation.  

PubMed

Astrocytes are known to serve as scaffolding cells that shape the brain. The physical properties of astrocytes, such as stiffness, are important for their scaffolding function. These properties may be altered in certain pathological conditions, such as in brain cancer. However, actual stiffness of astrocytes is not yet well understood. Here, we report that the astrocyte stiffness is positively correlated with the density of cytoskeletal proteins, such as actin filaments, microtubules, and intermediate filaments. The value of the stiffness of astrocytes as measured by atomic force microscopy (AFM) increases 38-fold in five-week-old rats compared to postnatal-day zero pups. Using multicolor confocal microscopy, we found that the complexity of cytoskeletal proteins, such as actin filaments, microtubules, and intermediate filaments, increase as the animal gets older. Our findings indicate that the change of stiffness positively correlates with the maturation of cytoskeletal proteins, and suggest that AFM can be useful as an analytical and diagnostic tool for neuroscience. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 365-370, 2015. PMID:24665040

Lee, Sang-Myung; Nguyen, Thi-Huong; Na, Kyounghwan; Cho, Il-Joo; Woo, Dong Ho; Oh, Jae-Eung; Lee, C Justin; Yoon, Eui-Sung

2015-01-01

283

Advances in Air-Sea Flux Measurement by Eddy Correlation  

NASA Astrophysics Data System (ADS)

Eddy-correlation measurements of the oceanic flux are useful for the development and validation of air-sea gas exchange models and for analysis of the marine carbon cycle. Results from more than a decade of published work and from two recent field programs illustrate the principal interferences from water vapour and motion, demonstrating experimental approaches for improving measurement precision and accuracy. Water vapour cross-sensitivity is the greatest source of error for flux measurements using infrared gas analyzers, often leading to a ten-fold bias in the measured flux. Much of this error is not related to optical contamination, as previously supposed. While various correction schemes have been demonstrated, the use of an air dryer and closed-path analyzer is the most effective way to eliminate this interference. This approach also obviates density corrections described by Webb et al. (Q J R Meteorol 106:85-100, 1980). Signal lag and frequency response are a concern with closed-path systems, but periodic gas pulses at the inlet tip provide for precise determination of lag time and frequency attenuation. Flux attenuation corrections are shown to be 5 % for a cavity ring-down analyzer (CRDS) and dryer with a 60-m inlet line. The estimated flux detection limit for the CRDS analyzer and dryer is a factor of ten better than for IRGAs sampling moist air. While ship-motion interference is apparent with all analyzers tested in this study, decorrelation or regression methods are effective in removing most of this bias from IRGA measurements and may also be applicable to the CRDS.

Blomquist, Byron W.; Huebert, Barry J.; Fairall, Christopher W.; Bariteau, Ludovic; Edson, James B.; Hare, Jeffrey E.; McGillis, Wade R.

2014-09-01

284

Measuring the first two statistics moments using the Correlator resources  

NASA Astrophysics Data System (ADS)

The ALMA telescope is composed of 66 high precision antennas, each antenna having 8 high bandwidth digitizers (4Gsamples/Second). It is a critical task to determine the well functioning of those digitizers prior to starting a round of observations. Since observation time is a valuable resource, it is germane that a tool be developed which can provide a quick and reliable answer regarding the digitizer status. Currently the digitizer output statistics are measured by using comparators and counters. This method introduced uncertainties due to the low amount of integration, in addition to going through all the possible states for all available digitizer time which all resulted in the antennas taking a considerable amount of time. In order to avoid the aforementioned described problems, a new method based on correlator resources is hereby presented.

Saez, A.; Herrera, D.; Sepulveda, Jorge

2014-07-01

285

A New Measurement of the 1S0 Neutron-Neutron Scattering Length using the Neutron-Proton Scattering Length as a Standard  

E-print Network

The present paper reports high-accuracy cross-section data for the 2H(n,nnp) reaction in the neutron-proton (np) and neutron-neutron (nn) final-state-interaction (FSI) regions at an incident mean neutron energy of 13.0 MeV. These data were analyzed with rigorous three-nucleon calculations to determine the 1S0 np and nn scattering lengths, a_np and a_nn. Our results are a_nn = -18.7 +/- 0.6 fm and a_np = -23.5 +/- 0.8 fm. Since our value for a_np obtained from neutron-deuteron (nd) breakup agrees with that from free np scattering, we conclude that our investigation of the nn FSI done simultaneously and under identical conditions gives the correct value for a_nn. Our value for a_nn is in agreement with that obtained in pion-deuteron capture measurements but disagrees with values obtained from earlier nd breakup studies.

D. E. Gonzalez Trotter; F. Salinas; Q. Chen; A. S. Crowell; W. Gloeckle; C. R. Howell; C. D. Roper; D. Schmidt; I. Slaus; H. Tang; W. Tornow; R. L. Walter; H. Witala; Z. Zhou

1999-08-11

286

openBEB: open biological experiment browser for correlative measurements  

PubMed Central

Background New experimental methods must be developed to study interaction networks in systems biology. To reduce biological noise, individual subjects, such as single cells, should be analyzed using high throughput approaches. The measurement of several correlative physical properties would further improve data consistency. Accordingly, a considerable quantity of data must be acquired, correlated, catalogued and stored in a database for subsequent analysis. Results We have developed openBEB (open Biological Experiment Browser), a software framework for data acquisition, coordination, annotation and synchronization with database solutions such as openBIS. OpenBEB consists of two main parts: A core program and a plug-in manager. Whereas the data-type independent core of openBEB maintains a local container of raw-data and metadata and provides annotation and data management tools, all data-specific tasks are performed by plug-ins. The open architecture of openBEB enables the fast integration of plug-ins, e.g., for data acquisition or visualization. A macro-interpreter allows the automation and coordination of the different modules. An update and deployment mechanism keeps the core program, the plug-ins and the metadata definition files in sync with a central repository. Conclusions The versatility, the simple deployment and update mechanism, and the scalability in terms of module integration offered by openBEB make this software interesting for a large scientific community. OpenBEB targets three types of researcher, ideally working closely together: (i) Engineers and scientists developing new methods and instruments, e.g., for systems-biology, (ii) scientists performing biological experiments, (iii) theoreticians and mathematicians analyzing data. The design of openBEB enables the rapid development of plug-ins, which will inherently benefit from the “house keeping” abilities of the core program. We report the use of openBEB to combine live cell microscopy, microfluidic control and visual proteomics. In this example, measurements from diverse complementary techniques are combined and correlated. PMID:24666611

2014-01-01

287

Determination of Axial Length Requiring Adjustment of Measured Circumpapillary Retinal Nerve Fiber Layer Thickness for Ocular Magnification  

PubMed Central

Purpose To determine the axial length requiring adjustment of measured circumpapillary retinal nerve fiber layer (cpRNFL) thickness to account for ocular magnification during spectral-domain optical coherence tomography (SD-OCT). Methods In this prospective study, 148 eyes of 148 healthy student volunteers were imaged by two examiners using three-dimensional SD-OCT. In 54 randomly selected eyes, total cpRNFL thickness was measured with and without adjustment for ocular magnification to establish intra-examiner and inter-examiner measurement error. The 148 eyes were then divided into three groups according to the error values: control group (difference in the corrected and uncorrected total cpRNFL thickness was within the measurement error range), thinner group (the corrected total cpRNFL thickness was less than the uncorrected one), and thicker group (the corrected total cpRNFL thickness was more than the uncorrected one). The cutoff values of axial length between the control and the other groups were calculated by receiver operating characteristic analysis. Results Measurement error ranged from 4.2 to 5.3 µm; the threshold value was defined as 5.3 µm. The cutoff values of axial length between the thinner and the control groups and between the control and the thicker groups were 23.60 (area under the curve [AUC]?=?0.959) and 25.55 (AUC?=?0.944) mm, respectively. Conclusions Axial lengths shorter than 23.60 mm and longer than 25.55 mm require adjustment of measured cpRNFL thickness to account for ocular magnification during SD-OCT. Clinical Trial Registration UMIN Clinical Trials Registry (http://www.umin.ac.jp/) under unique trial number UMIN000013248 (date of registration: 02/24/2014) PMID:25215521

Hirasawa, Kazunori; Shoji, Nobuyuki; Yoshii, Yukako; Haraguchi, Shota

2014-01-01

288

Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge  

NASA Astrophysics Data System (ADS)

A non-thermal gliding arc discharge was generated at atmospheric pressure in an air flow. The dynamics of the plasma column and tracer particles were recorded using two synchronized high-speed cameras. Whereas the data analysis for such systems has previously been performed in 2D (analyzing the single camera image), we provide here a 3D data analysis that includes 3D reconstructions of the plasma column and 3D particle tracking velocimetry based on discrete tomography methods. The 3D analysis, in particular, the determination of the 3D slip velocity between the plasma column and the gas flow, gives more realistic insight into the convection cooling process. Additionally, with the determination of the 3D slip velocity and the 3D length of the plasma column, we give more accurate estimates for the drag force, the electric field strength, the power per unit length, and the radius of the conducting zone of the plasma column.

Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan; Moseev, Dmitry; Kusano, Yukihiro; Salewski, Mirko; Alpers, Andreas; Gritzmann, Peter; Schwenk, Martin

2015-01-01

289

ABSOLUTE BUNCH LENGTH MEASUREMENTS AT THE ALS BY INCOHERENTSYNCHROTRON RADIATION FLUCTUATION ANALYSIS  

SciTech Connect

By analysing the pulse to pulse intensity fluctuations ofthe radiation emitted by a charge particle in the incoherent part of thespectrum, it is possible to extract information about the spatialdistribution of the beam. At the Advanced Light Source (ALS) of theLawrence Berkeley National Laboratory, we have developed and tested asimple scheme based on this principle that allows for the absolutemeasurement of the bunch length. A description of the method and theexperimental results are presented.

Sannibale, Fernando; Zolotorev, Max S.; Filippetto, Daniele; Stupakov, Gennady V.

2007-06-22

290

Dynamics of lithium ions in borotellurite mixed former glasses: correlation between the characteristic length scales of mobile ions and glass network structural units.  

PubMed

We have studied the mixed network former effect on the dynamics of lithium ions in borotellurite glasses in wide composition and temperature ranges. The length scales of ion dynamics, such as characteristic mean square displacement and spatial extent of sub-diffusive motion of lithium ions have been determined from the ac conductivity and dielectric spectra, respectively, in the framework of linear response theory. The relative concentrations of different network structural units have been determined from the deconvolution of the FTIR spectra. A direct correlation between the ion dynamics and the characteristic length scales and the relative concentration of BO4 units has been established for different compositions of the borotellurite glasses. PMID:25362322

Shaw, A; Ghosh, A

2014-10-28

291

Heme Carbonyls: Environmental Effects on ?C–O and Fe–C/C–O Bond Length Correlations  

PubMed Central

The synthesis and characterization of four low-spin (carbonyl)iron(II) tetraphenylporphyrinates, [Fe(TPP)(CO)(L)], where L = 1-methylimidazole, 2-methylimidazole, 1,2-dimethylimidazole (unsolvated) and 1,2-dimethylimidazole (toluene solvate) are reported. The complexes show nearly the same value of ?C–O in toluene solution (1969–72 cm?1) but a large range of CO stretching frequencies in the solid-state (1926–1968 cm?1). The large solid-state variation results from CO interactions in the solid-state as shown by an examination of the crystal structures of the four complexes. The high precision of the four structures obtained allows us to make a number of structural and spectroscopic correlations that describe the Fe–C–O and NIm–Fe–CO units. The values of ?C–O and the Fe–C and C–O bond distances are strongly correlated and provide a structural as well as a spectroscopic correlation of the ? back-bonding model. The interactions of CO described are closely related to the large range of CO stretching frequencies observed in heme proteins and specific interactions observed in carbonylmyoglobin (MbCO). PMID:16218637

Silvernail, Nathan J.; Roth, Arne; Noll, Bruce C.; Scheidt, W. Robert; Schulz, Charles E.

2006-01-01

292

TERC and TERT gene mutations in patients with bone marrow failure and the significance of telomere length measurements  

PubMed Central

Dyskeratosis congenita (DC) is a rare inherited form of bone marrow failure (BMF) caused by mutations in telomere maintaining genes including TERC and TERT. Here we studied the prevalence of TERC and TERT gene mutations and of telomere shortening in an unselected population of patients with BMF at our medical center and in a selected group of patients referred from outside institutions. Less than 5% of patients with BMF had pathogenic mutations in TERC or TERT. In patients with BMF, pathogenic TERC or TERT gene mutations were invariably associated with marked telomere shortening (? 1st percentile) in peripheral blood mononuclear cells (PBMCs). In asymptomatic family members, however, telomere length was not a reliable predictor for the presence or absence of a TERC or TERT gene mutation. Telomere shortening was not pathognomonic of DC, as approximately 30% of patients with BMF due to other causes had PBMC telomere lengths at the 1st percentile or lower. We conclude that in the setting of BMF, measurement of telomere length is a sensitive but nonspecific screening method for DC. In the absence of BMF, telomere length measurements should be interpreted with caution. PMID:18931339

Du, Hong-Yan; Pumbo, Elena; Ivanovich, Jennifer; An, Ping; Maziarz, Richard T.; Reiss, Ulrike M.; Chirnomas, Deborah; Shimamura, Akiko; Vlachos, Adrianna; Lipton, Jeffrey M.; Goyal, Rakesh K.; Goldman, Frederick; Wilson, David B.; Mason, Philip J.

2009-01-01

293

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

NASA Astrophysics Data System (ADS)

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, Wahnström, 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), 10.1103/PhysRevE.79.060501; K. Kim and S. Saito, J. Chem. Phys. 133, 044511 (2010), 10.1063/1.3464331]. 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.

Kim, Kang; Saito, Shinji

2013-03-01

294

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

295

Cascade gamma-gamma tomography and angular correlation measurements  

NASA Astrophysics Data System (ADS)

Cascade gamma-ray tomography depends on the measurement of two or more gamma-rays emitted from a radionuclide in coincidence. In using suitable detectors of appropriate timing resolution it may also be possible to obtain information about the 'chemical environment' of the radionuclide i.e. the binding site in the material to which it is attached by carrying out, simultaneously, time differential perturbed angular correlation (TDPAC) measurements. A dual block bismuth germanate (BGO) detector system, designed for use in positron emission tomography (PET) has been employed to perform cascade gamma-ray tomography with a point 60Co source (1173 and 1332 keV). It is shown that despite the poor energy resolution of the coincidence system, the point source can be imaged with a multi-hole collimator, on one or both detectors, with a resolution (full width at half maximum) of 3.8 and 2.4 +/- 0.2 mm respectively, at the expense of significantly reduced sensitivity. Practical constraints limit usefulness of the system which new scintillation systems, with respect to time and energy resolution, should overcome.

Spyrou, Nicholas M.; Mesbahi, M. Esmail; Mallion, Stephen N.

2000-04-01

296

An evaluation of deep-sea benthic megafauna length measurements obtained with laser and stereo camera methods  

NASA Astrophysics Data System (ADS)

The 25 year time-series collected at Station M, ~4000 m on the Monterey Deep-sea Fan, has substantially improved understanding of the role of the deep-ocean benthic environment in the global carbon cycle. However, the role of deep-ocean benthic megafauna in carbon bioturbation, remineralization and sequestration is relatively unknown. It is important to gather both accurate and precise measurements of megafaunal community abundance, size distribution and biomass to further define their role in deep-sea carbon cycling and possible sequestration. This study describes initial results from a stereo camera system attached to a remotely operated vehicle and analyzed using the EventMeasure photogrammetric measurement software to estimate the density, length and biomass of 10 species of mobile epibenthic megafauna. Stereo length estimates were compared to those from a single video camera system equipped with sizing lasers and analyzed using the Monterey Bay Aquarium Research Institute's Video Annotation and Reference System. Both camera systems and software were capable of high measurement accuracy and precision (<±1 mm measurement error and precision). However, the oblique angle of the single video camera caused the spatial scale of the image perspective to change with distance from the camera, resulting in error when measurements were not parallel or vertical to two horizontal-oriented scaling lasers. Analysis showed that the stereo system recorded longer lengths and higher biomass estimates than the single video camera system for the majority of the 10 megafauna species studied. The stereo image analysis process took substantially longer than the video analysis and the value of the EventMeasure software tool would be improved with developments in analysis automation. The stereo system is less influenced by object orientation and height, and is potentially a useful tool to be mounted on an autonomous underwater vehicle and for measuring deep-sea pelagic animals where the use of lasers is not feasible.

Dunlop, Katherine M.; Kuhnz, Linda A.; Ruhl, Henry A.; Huffard, Christine L.; Caress, David W.; Henthorn, Richard G.; Hobson, Brett W.; McGill, Paul; Smith, Kenneth L.

2015-02-01

297

Measurement and model prediction of proton-recoil track length distributions in NTA film dosimeters for neutron energy spectroscopy and retrospective dose assessment  

NASA Astrophysics Data System (ADS)

The goal of this research was to determine whether neutron dose reconstruction could be improved through re-analysis of historic NTA films worn by workers in the 1950 through the 1970s. To improve neutron dose reconstruction, the underlying neutron energy spectra is critical in determining the organ dose due to energy dependence of the dose conversion factor as well as the application of radiation weighting factors used in epidemiology and probability of causation calculations. Monte Carlo models of proton-recoil track length distributions were developed and benchmarked against measurement data for both NTA and Ilford films. These models, when applied to several NTA film dosimeter configurations, demonstrated that proton-recoil track length distributions change based upon incident neutron energy. The neutron energy spectra changes that result from the general work environment such as source term and shielding can subsequently be modeled to predict the response of the NTA film dosimeter. An Automatic NTA Film Analyzer has been designed and developed to determine if the difference in proton-recoil track length distributions predicted by the Monte Carlo models could be measured and whether these differences could be correlated to the incident neutron energy spectra. The design required the development of a 2D-3D hybrid track recognition algorithm for a three dimensional analysis of the NTA film in order to accurately determine the proton-recoil track length for subsequent neutron energy determination. NTA films exposed to a plutonium fluoride (PuF4) and polonium boron (PoB) calibration sources were measured and compared. The proton-recoil track lengths were used to reconstruct the incident neutron energy spectra demonstrating the functionality of the analyzer and that reconstruction of the neutron energy spectra from NTA films is feasible. These measurements were compared to the Monte Carlo models and confirmed the applicability of using models to determine the NTA film response. Based on the Monte Carlo Modeling and the Automatic NTA Film Analyzer, the neutron energy spectra to which an individual worker was exposed can be retrospectively determined through re-analysis of historic NTA dosimeter films thus improving retrospective neutron dose assessments.

Taulbee, Timothy D.

298

Method and apparatus for measuring minority carrier lifetimes and bulk diffusion length in P-N junction solar cells  

NASA Technical Reports Server (NTRS)

Carrier lifetimes and bulk diffusion length are qualitatively measured as a means for qualification of a P-N junction photovoltaic solar cell. High frequency (blue) monochromatic light pulses and low-frequency (red) monochromatic light pulses were alternately applied to the cell while it was irradiated by light from a solar simulator, and synchronously displaying the derivative of the output voltage of the cell on an oscilloscope. The output voltage is a measure of the lifetimes of the minority carriers (holes) in the diffused N layer and majority carriers (electrons) in the bulk P material, and of the diffusion length of the bulk silicon. By connecting a reference cell in this manner with a test cell to be tested in reverse parallel, the display of a test cell that matches the reference cell will be a substantially zero output.

Vonroos, O. H. (inventor)

1978-01-01

299

High-resolution, large dynamic range fiber length measurement based on a frequency-shifted asymmetric Sagnac interferometer.  

PubMed

We propose and experimentally demonstrate a single-mode fiber length and dispersion measurement system based on what we believe to be a novel frequency-shifted asymmetric Sagnac interferometer incorporating an acousto-optic modulator (AOM). By sweeping the driving frequency of the AOM, which is asymmetrically placed in the Sagnac loop, the optical length of the fiber can be determined by measuring the corresponding variation in the phase delay between the two counterpropagating light beams. Combined with a high-resolution data processing algorithm, this system yields a dynamic range from a few centimeters to 60 km (limited by our availability of long fibers) with a resolution of approximately 1 part per million for long fibers. PMID:16389807

Qi, Bing; Tausz, Andrew; Qian, Li; Lo, Hoi-Kwong

2005-12-15

300

High-resolution, large dynamic range fiber length measurement based on a frequency-shifted asymmetric Sagnac interferometer  

NASA Astrophysics Data System (ADS)

We propose and experimentally demonstrate a single-mode fiber length and dispersion measurement system based on what we believe to be a novel frequency-shifted asymmetric Sagnac interferometer incorporating an acousto-optic modulator (AOM). By sweeping the driving frequency of the AOM, which is asymmetrically placed in the Sagnac loop, the optical length of the fiber can be determined by measuring the corresponding variation in the phase delay between the two counterpropagating light beams. Combined with a high-resolution data processing algorithm, this system yields a dynamic range from a few centimeters to 60 km (limited by our availability of long fibers) with a resolution of ˜1 partpermillion for long fibers.

Qi, Bing; Tausz, Andrew; Qian, Li; Lo, Hoi-Kwong

2005-12-01

301

Pharmacologically induced erect penile length and stretched penile length are both good predictors of post-inflatable prosthesis penile length.  

PubMed

Inflatable penile prosthesis (IPP) remains the gold standard for the surgical treatment of refractory erectile dysfunction; however, current literature to aid surgeons on how best to counsel patients on their postoperative inflated penile length is lacking. The aim of this study was to identify preoperative parameters that could better predict postoperative penile length following insertion of an IPP. Twenty men were enrolled in a prospective study examining penile lengths before and after IPP surgery. Patients with Peyronie's disease were excluded from this analysis. Baseline preoperative characteristics, including body mass index, history of hypertension, diabetes, Sexual Health Inventory for Men scores and/or prior radical prostatectomy were recorded. All patients underwent implantation with a three-piece inflatable Coloplast penile prosthesis. We compared stretched penile length to pharmacologically induced erect lengths. Postoperatively, we measured inflated penile lengths at 6 weeks and assessed patients' perception of penile size at 12 weeks. The median (±interquartile range) stretched penile length and pharmacologically induced erect penile length was 15 (±3) and 14.25 (±2)?cm, respectively (P=0.5). Median post-prosthesis penile length (13.5±2.13?cm) was smaller than preoperative pharmacologically induced length (P=0.02) and preoperative stretched penile length (P=0.01). The majority of patients (70%) had a decrease in penile length (median loss 0.5±1.5?cm); however, this loss was perceptible by 43% of men. Stretched penile length and pharmacologically induced erect penile length were equally good predictors of postoperative inflated length (Spearman's correlation 0.8 and 0.9, respectively). Pharmacologically induced erect penile length and stretched penile lengths are equal predictors of post-prosthesis penile length. The majority of men will experience some decrease in penile length following prosthesis implantation; however <50% report a subjective loss of penile length. PMID:24430278

Osterberg, E C; Maganty, A; Ramasamy, R; Eid, J F

2014-01-01

302

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

303

A volumetric approach to path-length measurements is essential when treating radiotherapy with modulated beams.  

PubMed

The established dosimetric benefits of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy have lead to their increased use in prostate radiotherapy. Complimenting these techniques, volumetric image guidance has supported increased positional accuracy. In addition, 3-dimensional image guidance has also allowed for assessment of potential dosimetric variation that can be attributed to a deformation of either internal or external structures, such as rectal distension or body contour. Compounding these issues is the variation of tissue density through which the new field position passes and also the variation of dose across a modulated beam. Despite the growing level of interest in this area, there are only a limited number of articles that examine the effect of a variation in beam path length, particularly across a modulated field. IMRT and volumetric-modulated radiation therapy (VMAT) fields are dynamic in nature, and the dose gradient within these fields is variable. Assessment of variation of path length away from the beam?s central axis and across the entire field is vital where there is considerable variation of dose within the field, such as IMRT and VMAT. In these cases, reliance on the traditional central axis to focus skin distances is no longer appropriate. This article discusses these more subtle challenges that may have a significant clinical effect if left unrecognized and undervalued. PMID:24630910

Forde, Elizabeth; Booth, Jeremy; Leech, Michelle

2014-01-01

304

Precision intensities and angular correlation measurements in ^152Sm  

NASA Astrophysics Data System (ADS)

The samarium isotopic chain shows great structural change dripline-to-dripline; evolving from deformed at the proton dripline, through spherical near stability before undergoing another transformation near N=90 when large prolate deformation re-emerges. Lying at the midpoint of this latter transition is ^152Sm. Numerous models have been developed to explain ^152Sm in terms of either being at the critical point of a phase transition, or in terms of coexisting shapes. To test the validity of these different models, a beta-decay experiment was performed at the ATLAS facility at Argonne. The decay of ^152Eu to ^152Sm was studied through gamma-ray spectroscopy using Gammasphere. An extremely large data set was collected, consisting of > 7x10^9 gamma-gamma or higher fold events. This made possible a high precision measurement of energies and intensities and very definite angular correlation determinations. The new results resolve some previous experimental ambiguities and help to differentiate between theoretical models. Work supported by the DOE Office of Nuclear Physics under contract DE-AC02-06CH11357.

McCutchan, E. A.; Lister, C. J.; Zhu, S.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Seweryniak, D.

2010-11-01

305

Second-harmonic microscopy of unstained living cardiac myocytes: measurements of sarcomere length with 20-nm accuracy  

NASA Astrophysics Data System (ADS)

We extend second-harmonic generation (SHG) microscopy to the measurement of sarcomere length in unstained living cardiac myocytes with 20-nm accuracy. We quantify individual sarcomere shortening in the presence of saxitoxin and find that it is in agreement with mechanical measurements of atrial tissue contracture. This functional application of SHG microscopy is generally applicable to quantify the physiological effects of drugs on contractile tissue. Our data also suggest that packed myosin heads in sarcomere thick filaments are responsible for the large second-harmonic endogenous signal in muscle tissue.

Boulesteix, Thierry; Beaurepaire, Emmanuel; Sauviat, Martin-Pierre; Schanne-Klein, Marie-Claire

2004-09-01

306

Second-harmonic microscopy of unstained living cardiac myocytes: measurements of sarcomere length with 20-nm accuracy.  

PubMed

We extend second-harmonic generation (SHG) microscopy to the measurement of sarcomere length in unstained living cardiac myocytes with 20-nm accuracy. We quantify individual sarcomere shortening in the presence of saxitoxin and find that it is in agreement with mechanical measurements of atrial tissue contracture. This functional application of SHG microscopy is generally applicable to quantify the physiological effects of drugs on contractile tissue. Our data also suggest that packed myosin heads in sarcomere thick filaments are responsible for the large second-harmonic endogenous signal in muscle tissue. PMID:15455770

Boulesteix, Thierry; Beaurepaire, Emmanuel; Sauviat, Martin-Pierre; Schanne-Klein, Marie-Claire

2004-09-01

307

Measurement of the minority carrier diffusion length and edge surface-recombination velocity in InP  

NASA Technical Reports Server (NTRS)

A scanning electron microscope (SEM) was used to measure the electron (minority carrier) diffusion length (L(sub n)) and the edge surface-recombination velocity (V(sub s)) in zinc-doped Czochralski-grown InP wafers. Electron-beam-induced current (EBIC) profiles were obtained in specimens containing a Schottky barrier perpendicular to the scanned (edge) surface. An independent technique was used to measure V(sub s), and these values were used in a theoretical expression for normalized EBIC. A fit of the experimental data with this expression enabled us to determine L(sub n).

Bailey, Sheila G.; Hakimzadeh, Roshanak

1993-01-01

308

The spin Hall angle and spin diffusion length of Pd measured by spin pumping and microwave photoresistance  

SciTech Connect

We present the experimental study of the spin Hall angle (SHA) and spin diffusion length of Pd with the spin pumping and microwave photoresistance effects. The Py/Pd bilayer stripes are excited with an out-of-plane microwave magnetic field. The pure spin current is thus pumped and transforms into charge current via the inverse spin Hall effect (ISHE) in Pd layer, yielding an ISHE voltage. The ISHE voltage can be distinguished from the unwanted signal caused by the anisotropic magnetoresistance according to their different symmetries. Together with Pd thickness dependent measurements of in and out-of-plane precessing angles and effective spin mixing conductance, the SHA and spin-diffusion length of Pd are quantified as 0.0056?±?0.0007 and 7.3?±?0.7?nm, respectively.

Tao, X. D.; Feng, Z.; Miao, B. F.; Sun, L.; You, B.; Wu, D.; Du, J.; Zhang, W.; Ding, H. F., E-mail: hfding@nju.edu.cn [Department of Physics, National Laboratory of Solid State Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)

2014-05-07

309

Measurement and modification of biexciton-exciton time correlations.  

PubMed

Photons which are generated in a two-photon cascade process have an underlying time correlation since the spontaneous emission of the upper level populates the intermediate state. This correlation leads to a reduction of the purity of the photon emitted from the intermediate state. Here we characterize this time correlation for the biexciton-exciton cascade of an InAs/GaAs quantum dot. We show that the correlation can be reduced by tuning the biexciton transition in resonance to a planar distributed Bragg reflector cavity. The enhanced and inhibited emission into the cavity accelerates the biexciton emission and slows down the exciton emission thus reduces the correlation and increases the purity of the exciton photon. This is essential for schemes like creating time-bin entangled photon pairs from quantum dot systems. PMID:23609694

Huber, Tobias; Predojevi?, Ana; Zoubi, Hashem; Jayakumar, Harishankar; Solomon, Glenn S; Weihs, Gregor

2013-04-22

310

MEALWORM MORPHOLOGY Objective: Learn the anatomy of a mealworm and measure body length, body mass, the  

E-print Network

MEALWORM MORPHOLOGY Objective: Learn the anatomy of a mealworm and measure body different mealworms using the balances, digital microscopes, and ImageJ. Procedure: 1. Send ONE person from your group up to collect 5 mealworms from

Rose, Michael R.

311

Linking HOBIC measures with length of stay and alternate levels of care: implications for nurse leaders in their efforts to improve patient flow and quality of care.  

PubMed

Integral to understanding and leveraging performance data to monitor and drive quality improvement (QI) efforts to enhance patient care is a partnership between researchers (who generate data) and nurse executives (who lead QI efforts). In Canada, evidence-based, nursing-sensitive patient outcome data are included in the Health Outcomes for Better Information and Care (HOBIC) initiative. A descriptive study was undertaken to examine the relationships and predictive abilities of HOBIC measures with length of stay (LOS) and alternate levels of care (ALC) measures. Specifically, we were interested in determining (a) whether relationships among the HOBIC measures exist and (b) whether any of the HOBIC measures are associated with, and could subsequently be used to predict, the patient and the destination to which he or she is discharged (ALC). Our interest in understanding these relationships and predictive abilities was both research driven and practice driven, with the intent eventually to use study findings to target clinical practice and data feedback strategies. To address the two research aims, this study employed both descriptive and inferential statistical approaches with multiple analytic approaches. Study results suggest that many of the HOBIC measures are related, with a higher score in one measure corresponding to a higher score in another measure. The exception is the therapeutic self-care (TSC) measure, in which higher scores on other HOBIC measures were correlated with lower TSC scores. Associations were also found with the predictive ability of certain HOBIC measures on LOS and ALC. Our study findings call for nurse leaders to emphasize the importance to clinical nurses on hospital units of focusing their efforts on assisting patients in managing their fatigue and dyspnoea effectively; increasing their ability to engage in activities of daily living, functional status and therapeutic self-care; and preventing or minimizing pressure ulcers and falls in acute care patients. In turn, these efforts may decrease patients' LOS. PMID:23803426

Jeffs, Lianne; Jiang, Depeng; Wilson, Gail; Ferris, Ella; Cardiff, Brenda; Lanceta, Mary; White, Peggy; Pringle, Dorothy

2012-12-01

312

Water equivalent path length measurement in proton radiotherapy using time resolved diode dosimetry  

SciTech Connect

Purpose: To verify water equivalent path length (WEPL) before treatment in proton radiotherapy using time resolved in vivo diode dosimetry. Methods: Using a passively scattered range modulated proton beam, the output of a diode driving a fast current-to-voltage amplifier is recorded at a number of depths in a water tank. At each depth, a burst of overlapping single proton pulses is observed. The rms duration of the burst is computed and the resulting data set is fitted with a cubic polynomial. Results: When the diode is subsequently set to an arbitrary depth and the polynomial is used as a calibration curve, the ''unknown'' depth is determined within 0.3 mm rms. Conclusions: A diode or a diode array, placed (for instance) in the rectum in conjunction with a rectal balloon, can potentially determine the WEPL at that point, just prior to treatment, with submillimeter accuracy, allowing the beam energy to be adjusted. The associated unwanted dose is about 0.2% of a typical single fraction treatment dose.

Gottschalk, B.; Tang, S.; Bentefour, E. H.; Cascio, E. W.; Prieels, D.; Lu, H.-M. [Laboratory for Particle Physics and Cosmology, Harvard University, 18 Hammond Street, Cambridge, Massachusetts 02138 (United States); Francis H. Burr Proton Therapy Center, Boston, Massachusetts 02114 (United States); Ion Beam Applications S.A., Louvain-la-Neuve 1348 (Belgium); Francis H. Burr Proton Therapy Center, Boston, Massachusetts 02114 (United States); Ion Beam Applications S.A., Louvain-la-Neuve 1348 (Belgium); Francis H. Burr Proton Therapy Center, Boston, Massachusetts 02114 (United States)

2011-04-15

313

The understanding of length-of-day variations from satellite gravity and laser ranging measurements  

NASA Astrophysics Data System (ADS)

The change in the rate of the Earth's rotation, length-of-day (LOD), is principally the result of movement and redistribution of mass in the Earth's atmosphere, oceans and hydrosphere. Numerous studies on the LOD excitations have been made from climatological/hydrological assimilation systems and models of the general circulation of the ocean. However, quantitative assessment and understanding of the contributions to the LOD remain unclear due mainly to the lack of direct global observations. In this paper, the total Earth's surface fluids mass excitations to the LOD at seasonal and intraseasonal timescales are investigated from the Jet Propulsion Laboratory Estimating Circulation and Climate of the Ocean (ECCO) model, the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis and the European Center for Medium-Range Weather Forecasts (ECMWF) Re-analysis (ERA)-Interim, GRACE-derived surface fluids mass and the spherical harmonics coefficient C20 from the satellite laser ranging (SLR) as well as combined GRACE+SLR solutions, respectively. Results show that the GRACE and the combined GRACE and SLR solutions better explain the geodetic residual LOD excitations at annual and semi-annual timescales. For less than 1 yr timescales, GRACE-derived mass is worse to explain the geodetic residuals, whereas SLR agrees better with the geodetic residuals. However, the combined GRACE and SLR results are much improved in explaining the geodetic residual excitations at intraseasonal scales.

Jin, Shuanggen; Zhang, L. J.; Tapley, B. D.

2011-02-01

314

Site-specific PEGylation of hemoglobin at Cys-93(beta): correlation between the colligative properties of the PEGylated protein and the length of the conjugated PEG chain.  

PubMed

Increasing the molecular size of acellular hemoglobin (Hb) has been proposed as an approach to reduce its undesirable vasoactive properties. The finding that bovine Hb surface decorated with about 10 copies of PEG5K per tetramer is vasoactive provides support for this concept. The PEGylated bovine Hb has a strikingly larger molecular radius than HbA (1). The colligative properties of the PEGylated bovine Hb are distinct from those of HbA and even polymerized Hb, suggesting a role for the colligative properties of PEGylated Hb in neutralizing the vasoactivity of acellular Hb. To correlate the colligative properties of surface-decorated Hb with the mass of the PEG attached and also its vasoactivity, we have developed a new maleimide-based protocol for the site-specific conjugation of PEG to Hb, taking advantage of the unusually high reactivity of Cys-93(beta) of oxy HbA and the high reactivity of the maleimide to protein thiols. PEG chains of 5, 10, and 20 kDa have been functionalized at one of their hydroxyl groups with a maleidophenyl moiety through a carbamate linkage and used to conjugate the PEG chains at the beta-93 Cys of HbA to generate PEGylated Hbs carrying two copies of PEG (of varying chain length) per tetramer. Homogeneous preparations of (SP-PEG5K)(2)-HbA, (SP-PEG10K)(2)-HbA, and (SP-PEG20K)(2)-HbA have been isolated by ion exchange chromatography. The oxygen affinity of Hb is increased slightly on PEGylation, but the length of the PEG-chain had very little additional influence on the O(2) affinity. Both the hydrodynamic volume and the molecular radius of the Hb increased on surface decoration with PEG and exhibited a linear correlation with the mass of the PEG chain attached. On the other hand, both the viscosity and the colloidal osmotic pressure (COP) of the PEGylated Hbs exhibited an exponential increase with the increase in PEG chain length. In contrast to the molecular volume, viscosity, and COP, the vasoactivity of the PEGylated Hbs was not a direct correlate of the PEG chain length. There appeared to be a threshold for the PEG chain length beyond which the protection against vasoactivity is decreased. These results suggest that the modulation of the vasoactivity of Hb by PEG could be a function of the surface shielding afforded by the PEG, the latter being a function of the disposition of the PEG chain on the protein surface, which in turn is a function of the length of the PEG chain. Thus, the biochemically homogeneous PEGylated Hbs described in the present study, surface-decorated with PEG chains of appropriate size, could serve as potential candidates for Hb-based oxygen carriers. PMID:12643758

Manjula, B N; Tsai, A; Upadhya, R; Perumalsamy, K; Smith, P K; Malavalli, A; Vandegriff, K; Winslow, R M; Intaglietta, M; Prabhakaran, M; Friedman, J M; Acharya, A S

2003-01-01

315

Correlation  

Microsoft Academic Search

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

James Burt Miner

1919-01-01

316

Expectations for dihadron correlation measurements extrapolated to 5.5A TeV  

SciTech Connect

The suppression of high transverse momentum (P{sub T}) inclusive hadron spectra in heavy-ion collisions as compared to the scaled expectation of high P{sub T} hadron production in p-p collisions is the most direct manifestation of the interaction of hard partons with the soft bulk medium produced in heavy-ion collisions which is absent in p-p collisions. Yet the measured nuclear suppression factor R{sub AA} is a very averaged quantity and hence only a limited amount of information about the medium evolution and the nature of the interaction with the medium can be deduced from R{sub AA}. Measurements of hard back-to-back hadron correlations in 200A GeV Au-Au collisions at RHIC have opened a new window to study the energy loss of partons in a medium in a more differential way and for a different distribution of in-medium path lengths than in the case of R{sub AA}. In this work, we present an extrapolation of our results for back-to-back yields at RHIC energies to 5.5 TeV Pb-Pb collisions at the CERN LHC. We also discuss differences and similarities between the measurement at RHIC.

Renk, Thorsten; Eskola, Kari J. [Department of Physics, P. O. Box 35, University of Jyvaeskylae, FI-40014 Jyvaeskylae (Finland) and Helsinki Institute of Physics, P. O. Box 64, University of Helsinki, FI-00014 Helsinki (Finland)

2008-04-15

317

Multi-photon correlations for nonclassical light measured in the pulsed regime  

Microsoft Academic Search

We demonstrate a technique of measuring Glauberpsilas normalized correlation functions for nonclassical light generated in the pulsed regime. In particular, intensity correlation functions are studied for the transition between spontaneous and stimulated parametric down-conversion.

I. N. Agafonov; M. V. Chekhova; O. A. Ivanova; T. I. Iskhakov

2006-01-01

318

Criteria of quantum correlation in the measurement of continuous variables in optics  

E-print Network

The purpose of this short tutorial paper is to review various criteria that have been used to characterize the quantum character of correlations in optical systems, such as "gemellity", QND correlation, intrication, EPR correlation and Bell correlation, to discuss and compare them. This discussion, restricted to the case of measurements of continuous optical variables, includes also an extension of known criteria for "twin beams" to the case of imbalanced correlations.

Nicolas Treps; Claude Fabre

2004-07-27

319

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

E-print Network

RNA using two different single-molecule techniques: magnetic tweezers and atomic force microscopy. We deduce with the magnetic tweezers. We present atomic force microscopy images of dsRNA and demonstrate a new method single- molecule techniques, magnetic tweezers and atomic force microscopy (AFM), to measure its

Dekker, Nynke

320

Measurement of viscoelastic properties at small length scales for heterogeneous and nonlinear materials  

NASA Astrophysics Data System (ADS)

In this dissertation, advances in linear and non-linear viscoelastic analysis and experimentation have been employed to investigate the properties of materials using nanoindentation. In the first study, a general linear-viscoelastic model was developed to measure the properties of polydimethylsiloxane (PDMS) using a flat punch indenter. Subsequently, linear viscoelastic nanoindentation was used to measure the young's relaxation modulus of a locally-heterogeneous thermally-aged bismaleimide resin using a Berkovich indenter. Nanoindentation measurements were conducted on both surface and cross section of aged bismaleimide resin specimens with different aging time at 200°C and 300°C respectively to extract the oxidation effect of sample under high temperatures. Finally, nanoindentation measurements were made on human tympanic membrane specimens with using a spherical nanoindenter tip in direct contact with the collagen fiber layer. Linear viscoelastic analysis was conducted to extract the Young's relaxation modulus distributions. The study also focused on the development of non-linear viscoelastic analysis of indentation experiments. Despite the fact that the nanoindentation technique is well established for the characterization of elasto-plastic materials, nanoindentation on viscoelastic materials is not fully understood especially in nonlinear viscoelastic region. In the dissertation, a nonlinear viscoelastic model was developed and implemented in Abaqus/Implicit Code to analyze the nonlinear visceoelastic behavior of polyvinyl acetate (PVA) under nanoindentation.

Wang, Fang

321

GROUND VIBRATION AND COHERENCE LENGTH MEASUREMENTS FOR THE CLIC NANO-STABILIZATION STUDIES  

E-print Network

, closed loop alignment mechanisms will be implemented for the girders with accelerating structures (ACS and emittances in future linear accelerators result in stringent alignment and nanometre vibration stability for feasibility studies of linear accelerators. Recent measurements were performed in the LHC tunnel

Boyer, Edmond

322

Measuring spin correlations in optical lattices using superlattice potentials  

SciTech Connect

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.; Soerensen, A. S. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen O (Denmark); Bruun, G. M. [Department of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Aarhus C (Denmark); Syljuaasen, O. F. [Department of Physics, University of Oslo, P. O. Box 1048 Blindern, N-0316 Oslo (Norway)

2011-10-15

323

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

2011-11-18

324

Neutron interferometric measurement of the scattering length difference between the triplet and singlet states of n-$^3$He  

E-print Network

We report a determination of the n-$^3$He scattering length difference $\\Delta b^{\\prime} = b_{1}^{\\prime}-b_{0}^{\\prime} = $ ($-5.411$ $\\pm$ $0.031$ (statistical) $\\pm$ $0.039$ (systematic)) fm between the triplet and singlet states using a neutron interferometer. This revises our previous result $\\Delta b^{\\prime} = $ (-5.610 $\\pm$ $0.027$ (statistical) $\\pm$ $0.032$ (systematic) fm obtained using the same technique in 2008. This revision is due to a re-analysis of the 2008 experiment that includes a more robust treatment of the phase shift caused by magnetic field gradients near the $^3$He cell. Furthermore, we more than doubled our original data set from 2008 by acquiring six months of additional data in 2013. Both the new data set and a re-analysis of the older data are in good agreement. Scattering lengths of low Z isotopes are valued for use in few-body nuclear effective field theories, provide important tests of modern nuclear potential models and in the case of $^3$He aid in the interpretation of neutron scattering from quantum liquids. The difference $\\Delta b^{\\prime}$ was determined by measuring the relative phase shift between two incident neutron polarizations caused by the spin-dependent interaction with a polarized $^3$He target. The target $^3$He gas was sealed inside a small, flat windowed glass cell that was placed in one beam path of the interferometer. The relaxation of $^3$He polarization was monitored continuously with neutron transmission measurements. The neutron polarization and spin flipper efficiency were determined separately using $^3$He analyzers and two different polarimetry analysis methods. A summary of the measured scattering lengths for n-$^3$He with a comparison to nucleon interaction models is given.

M. G. Huber; M. Arif; W. C. Chen; T. R. Gentile; D. S. Hussey; T. C. Black; D. A. Pushin; C. B. Shahi; F. E. Wietfeldt; L. Yang

2014-09-30

325

Neutron interferometric measurement of the scattering length difference between the triplet and singlet states of n -3He  

NASA Astrophysics Data System (ADS)

We report a determination of the n -3He scattering length difference ? b'=b1'-b0'=[-5.411 ±0.031 (statistical)±0.039 (systematic)] fm between the triplet and singlet states using a neutron interferometer. This revises our previous result ? b'=[-5.610 ±0.027 (statistical)±0.032 (systematic)] fm obtained using the same technique in 2008 [Huber et al., Phys. Rev. Lett. 102, 200401 (2009), 10.1103/PhysRevLett.102.200401; Huber et al., Phys. Rev. Lett. 103, 179903(E) (2009), 10.1103/PhysRevLett.103.179903]. This revision is attributable to a reanalysis of the 2008 experiment that now includes a systematic correction caused by magnetic-field gradients near the 3He cell which had been previously underestimated. Furthermore, we more than doubled our original data set from 2008 by acquiring 6 months of additional data in 2013. Both the new data set and a reanalysis of the older data are in good agreement. Scattering lengths of low-Z isotopes are valued for use in few-body nuclear effective field theories, provide important tests of modern nuclear potential models, and, in the case of 3He, aid in the interpretation of neutron scattering from quantum liquids. The difference ? b' was determined by measuring the relative phase shift between two incident neutron polarizations caused by the spin-dependent interaction with a polarized 3He target. The target 3He gas was sealed inside a small, flat-windowed glass cell that was placed in one beam path of the interferometer. The relaxation of 3He polarization was monitored continuously with neutron transmission measurements. The neutron polarization and spin-flipper efficiency were determined separately using 3He analyzers and two different polarimetry analysis methods. A summary of the measured scattering lengths for n -3He with a comparison to nucleon interaction models is given.

Huber, M. G.; Arif, M.; Chen, W. C.; Gentile, T. R.; Hussey, D. S.; Black, T. C.; Pushin, D. A.; Shahi, C. B.; Wietfeldt, F. E.; Yang, L.

2014-12-01

326

Ultrasonographic measurement of liver length in the small-for-gestational-age fetus  

Microsoft Academic Search

Objective: Our purpose was to measure fetal liver size in small-for-gestational-age fetuses diagnosed by ultrasonography and to determine whether the small abdominal circumference used to diagnose small for gestational age is the result of a small liver. Study Design: Ninety-eight pregnant women who were diagnosed as having a fetus that was small for gestational age were included. All had a

Alistair B. Roberts; Jennifer M. Mitchell; Lesley M. McCowan; Sarah Barker

1999-01-01

327

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

328

Correlation  

NSDL National Science Digital Library

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

Christmann, Edwin P.; Badgett, John L.

2008-11-01

329

Quantum correlation evolution of GHZ and states under noisy channels using ameliorated measurement-induced disturbance  

NASA Astrophysics Data System (ADS)

We study quantum correlation of Greenberger-Horne-Zeilinger (GHZ) and W states under various noisy channels using measurement-induced disturbance approach and its optimized version. Although these inequivalent maximal entangled states represent the same quantum correlation in the absence of noise, it is shown that the W state is more robust than the GHZ state through most noisy channels. Also, using measurement-induced disturbance measure, we obtain the analytical relations for the time evolution of quantum correlations in terms of the noisy parameter and remove its overestimating quantum correlations upon implementing the ameliorated measurement-induced disturbance.

Espoukeh, Pakhshan; Pedram, Pouria

2015-01-01

330

Measurements of Dihadron Correlations Relative to the Event Plane in Au+Au Collisions at $\\sqrt{s_{NN}}=200$ GeV  

E-print Network

Dihadron azimuthal correlations containing a high transverse momentum ($\\pt$) trigger particle are sensitive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium, i.e. jet-quenching. Previous measurements revealed a strong modification to dihadron azimuthal correlations in Au+Au collisions with respect to \\pp\\ and \\dAu\\ collisions. The modification increases with the collision centrality, suggesting a path-length dependence to the jet-quenching effect. This paper reports STAR measurements of dihadron azimuthal correlations in mid-central (20-60\\%) Au+Au collisions at $\\snn=200$~GeV as a function of the trigger particle's azimuthal angle relative to the event plane, $\\phis=|\\phit-\\psiEP|$. The azimuthal correlation is studied as a function of both the trigger and associated particle $\\pt$. The subtractions of the combinatorial background and anisotropic flow, assuming Zero Yield At Minimum (\\zyam), are described. The away-side correlation is strongly modified, and the modification varies with $\\phis$, which is expected to be related to the path-length that the away-side parton traverses. The pseudo-rapidity ($\\deta$) dependence of the near-side correlation, sensitive to long range $\\deta$ correlations (the ridge), is also investigated. The ridge and jet-like components of the near-side correlation are studied as a function of $\\phis$. The ridge appears to drop with increasing $\\phis$ while the jet-like component remains approximately constant. ...

H. Agakishiev; M. M. Aggarwal; Z. Ahammed; A. V. Alakhverdyants; I. Alekseev; J. Alford; B. D. Anderson; C. D. Anson; D. Arkhipkin; G. S. Averichev; J. Balewski; D. R. Beavis; N. K. Behera; R. Bellwied; M. J. Betancourt; R. R. Betts; A. Bhasin; A. K. Bhati; H. Bichsel; J. Bielcik; J. Bielcikova; B. Biritz; L. C. Bland; W. Borowski; J. Bouchet; E. Braidot; A. V. Brandin; A. Bridgeman; S. G. Brovko; E. Bruna; S. Bueltmann; I. Bunzarov; T. P. Burton; X. Z. Cai; H. Caines; M. Calderón de la Barca Sánchez; D. Cebra; R. Cendejas; M. C. Cervantes; Z. Chajecki; P. Chaloupka; S. Chattopadhyay; H. F. Chen; J. H. Chen; J. Y. Chen; L. Chen; J. Cheng; M. Cherney; A. Chikanian; K. E. Choi; W. Christie; P. Chung; M. J. M. Codrington; R. Corliss; J. G. Cramer; H. J. Crawford; S. Dash; A. Davila Leyva; L. C. De Silva; R. R. Debbe; T. G. Dedovich; A. A. Derevschikov; R. Derradi de Souza; L. Didenko; P. Djawotho; S. M. Dogra; X. Dong; J. L. Drachenberg; J. E. Draper; J. C. Dunlop; L. G. Efimov; M. Elnimr; J. Engelage; G. Eppley; M. Estienne; L. Eun; O. Evdokimov; R. Fatemi; J. Fedorisin; R. G. Fersch; P. Filip; E. Finch; V. Fine; Y. Fisyak; C. A. Gagliardi; D. R. Gangadharan; A. Geromitsos; F. Geurts; P. Ghosh; Y. N. Gorbunov; A. Gordon; O. Grebenyuk; D. Grosnick; S. M. Guertin; A. Gupta; W. Guryn; B. Haag; O. Hajkova; A. Hamed; L-X. Han; J. W. Harris; J. P. Hays-Wehle; M. Heinz; S. Heppelmann; A. Hirsch; E. Hjort; G. W. Hoffmann; D. J. Hofman; B. Huang; H. Z. Huang; T. J. Humanic; L. Huo; G. Igo; P. Jacobs; W. W. Jacobs; C. Jena; F. Jin; J. Joseph; E. G. Judd; S. Kabana; K. Kang; J. Kapitan; K. Kauder; H. Ke; D. Keane; A. Kechechyan; D. Kettler; D. P. Kikola; J. Kiryluk; A. Kisiel; V. Kizka; A. G. Knospe; D. D. Koetke; T. Kollegger; J. Konzer; I. Koralt; L. Koroleva; W. Korsch; L. Kotchenda; V. Kouchpil; P. Kravtsov; K. Krueger; M. Krus; L. Kumar; P. Kurnadi; M. A. C. Lamont; J. M. Landgraf; S. LaPointe; J. Lauret; A. Lebedev; R. Lednicky; J. H. Lee; W. Leight; M. J. LeVine; C. Li; L. Li; N. Li; W. Li; X. Li; X. Li; Y. Li; Z. M. Li; M. A. Lisa; F. Liu; H. Liu; J. Liu; T. Ljubicic; W. J. Llope; R. S. Longacre; W. A. Love; Y. Lu; E. V. Lukashov; X. Luo; G. L. Ma; Y. G. Ma; D. P. Mahapatra; R. Majka; O. I. Mall; L. K. Mangotra; R. Manweiler; S. Margetis; C. Markert; H. Masui; H. S. Matis; Yu. A. Matulenko; D. McDonald; T. S. McShane; A. Meschanin; R. Milner; N. G. Minaev; S. Mioduszewski; A. Mischke; M. K. Mitrovski; B. Mohanty; M. M. Mondal; B. Morozov; D. A. Morozov; M. G. Munhoz; M. Naglis; B. K. Nandi; T. K. Nayak; P. K. Netrakanti; L. V. Nogach; S. B. Nurushev; G. Odyniec; A. Ogawa; Oh; Ohlson; V. Okorokov; E. W. Oldag; D. Olson; M. Pachr; B. S. Page; S. K. Pal; Y. Pandit; Y. Panebratsev; T. Pawlak; H. Pei; T. Peitzmann; C. Perkins; W. Peryt; S. C. Phatak; P. Pile; M. Planinic; M. A. Ploskon; J. Pluta; D. Plyku; N. Poljak; A. M. Poskanzer; B. V. K. S. Potukuchi; C. B. Powell; D. Prindle; C. Pruneau; N. K. Pruthi; P. R. Pujahari; J. Putschke; H. Qiu; R. Raniwala; S. Raniwala; R. L. Ray; R. Redwine; R. Reed; H. G. Ritter; J. B. Roberts; O. V. Rogachevskiy; J. L. Romero; A. Rose; L. Ruan; J. Rusnak; N. R. Sahoo; S. Sakai; I. Sakrejda; T. Sakuma; S. Salur; J. Sandweiss; E. Sangaline; A. Sarkar; J. Schambach; R. P. Scharenberg; A. M. Schmah; T. R. Schuster; J. Seele; J. Seger; I. Selyuzhenkov; P. Seyboth; E. Shahaliev; M. Shao; M. Sharma; S. S. Shi; Q. Y. Shou; E. P. Sichtermann; F. Simon; R. N. Singaraju; M. J. Skoby; N. Smirnov; H. M. Spinka; B. Srivastava; T. D. S. Stanislaus; D. Staszak; S. G. Steadman; J. R. Stevens; R. Stock; M. Strikhanov; B. Stringfellow; A. A. P. Suaide; M. C. Suarez; N. L. Subba; M. Sumbera; X. M. Sun; Y. Sun; Z. Sun; B. Surrow; D. N. Svirida; T. J. M. Symons; A. Szanto de Toledo; J. Takahashi; A. H. Tang; Z. Tang; L. H. Tarini; T. Tarnowsky; D. Thein; J. H. Thomas; J. Tian; A. R. Timmins; D. Tlusty; M. Tokarev; V. N. Tram; S. Trentalange; R. E. Tribble; Tribedy; O. D. Tsai; T. Ullrich; D. G. Underwood; G. Van Buren; G. van Nieuwenhuizen; J. A. Vanfossen, Jr.; R. Varma; G. M. S. Vasconcelos; A. N. Vasiliev; F. Videbæk; Y. P. Viyogi; S. Vokal; M. Wada; M. Walker; F. Wang; G. Wang; H. Wang; J. S. Wang; Q. Wang; X. L. Wang; Y. Wang; G. Webb; J. C. Webb; G. D. Westfall; C. Whitten Jr.; H. Wieman; S. W. Wissink; R. Witt; W. Witzke; Y. F. Wu; Xiao; W. Xie; H. Xu; N. Xu; Q. H. Xu; W. Xu; Y. Xu; Z. Xu; L. Xue; Y. Yang; P. Yepes; K. Yip; I-K. Yoo; M. Zawisza; H. Zbroszczyk; W. Zhan; J. B. Zhang; S. Zhang; W. M. Zhang; X. P. Zhang; Y. Zhang; Z. P. Zhang; J. Zhao; C. Zhong; W. Zhou; X. Zhu; Y. H. Zhu; R. Zoulkarneev; Y. Zoulkarneeva

2010-10-04

331

Determining uncertainties of correlated measurements by Monte Carlo simulations applied to laserscanning  

NASA Astrophysics Data System (ADS)

The determination of uncertainties according to the “Guide to the Expression of Uncertainty in Measurement (GUM)” is extended to correlated measurements. The correlations are estimated by repeated observations. Uniform, trapezoidal and triangular distributions recommended by GUM are generalized to multivariate distributions by Monte Carlo simulations. To introduce the Type B component of uncertainty of GUM, which expresses uncertainty based on experience, two methods are discussed. The first one introduces individual corrections to the measurements with identical variances, the second one an identical correction with the same variance to each observation. Correlations are caused by the latter method. The correlations of the coordinates of points measured by the laserscanner Leica HDS 3000 are estimated from repeated observations. Except for the correlations of the three coordinates of the same points, the correlations turn out to be small. Nevertheless, they should be considered for the uncertainties of distances derived from the coordinates, especially if an addition constant for the measured distances of the laserscanner is introduced.

Koch, Karl-Rudolf

2008-09-01

332

SPM measurements of graphene corrugation and spatial correlation  

Microsoft Academic Search

In order to determine the effect of graphene corrugation on electronic transport, it is most important to know the spatial correlation properties of the corrugated graphene structure. In spite of much experimental effort, there is still contentious debate about the structure of graphene, both in supported and suspended geometries. It has frequently been asserted that a graphene monolayer exfoliated onto

William Cullen; Jianhao Chen; Masa Ishigami; Ellen Williams; Michael Fuhrer

2009-01-01

333

Benefits of Time Correlation Measurements for Passive Screening  

NASA Astrophysics Data System (ADS)

The “FLASH Portals Project” is a collaboration between Arktis Radiation Detectors Ltd (CH), the Atomic Weapons Establishment (UK), and the Joint Research Centre (European Commission), supported by the Technical Support Working Group (TSWG). The program's goal was to develop and demonstrate a technology to detect shielded special nuclear materials (SNM) more efficiently and less ambiguously by exploiting time correlation. This study presents experimental results of a two-sided portal monitor equipped with in total 16 4He fast neutron detectors as well as four polyvinyltoluene (PVT) plastic scintillators. All detectors have been synchronized to nanosecond precision, thereby allowing the resolution of time correlations from timescales of tens of microseconds (such as (n, ?) reactions) down to prompt fission correlations directly. Our results demonstrate that such correlations can be detected in a typical radiation portal monitor (RPM) geometry and within operationally acceptable time scales, and that exploiting these signatures significantly improves the performance of the RPM compared to neutron counting. Furthermore, the results show that some time structure remains even in the presence of heavy shielding, thus significantly improving the sensitivity of the detection system to shielded SNM.

Murer, David; Blackie, Douglas; Peerani, Paolo

2014-02-01

334

Atmospheric pollution measurement by optical cross correlation methods - A concept  

NASA Technical Reports Server (NTRS)

Method combines standard spectroscopy with statistical cross correlation analysis of two narrow light beams for remote sensing to detect foreign matter of given particulate size and consistency. Method is applicable in studies of generation and motion of clouds, nuclear debris, ozone, and radiation belts.

Fisher, M. J.; Krause, F. R.

1971-01-01

335

Absolute detector quantum-efficiency measurements using correlated photons  

E-print Network

and Technology (NIST). We use pairs of correlated photons to produce spatial maps of the absolute efficiency of parametric down-conversion, which produces optical photons in pairs within a nonlinear crystal. Within the crystal, photons from a pump laser beam, in effect "decay" into pairs of photons under the restrictions

Migdall, Alan

336

Methods for estimating peak physiological performance and correlating performance measures  

E-print Network

on sample size. Here, we suggest an alternative approach that involves estimating a specific performance of sample size. Additionally, we address the estimation of correlations between two different performance by an unknown amount. Moreover, the magnitude of the bias depends on sample size, since a larger sample size

Hardin, Jo

337

On measuring and testing the ordinal correlation between  

E-print Network

; Kendall's tau, Outranking rela- tions; Bipolar credibility valuation. Introduction When proposing comparison of bipolarly-valued binary relations [5, 6]. This work is motivated, first, by the need to fine concerning the formal and empirical analysis of the fuzzy gamma rank correlation coefficient [4]. After

Bisdorff, Raymond

338

Transverse Emittance Measurements from a Photocathode RF Gun with Variable Laser Pulse Length  

SciTech Connect

The Gun Test Facility (GTF) at SSRL was started in 1996 to develop an appropriate injector for the proposed Linac Coherent Light Source (LCLS) at SLAC. The LCLS design requires the injector to produce a beam with at least 1 nC of charge in a 10 ps or shorter pulse with no greater than 1 pi mm-mrad normalized rms emittance. The photoinjector at the GTF is 1.6 cell S-band symmetrized gun and emittance compensation solenoid. Emittance measurements, reported here, were made as function of laser pulse width using Gaussian longitudinal pulses. The lowest achieved emittance to date with 1 nC of charge is 5.6 pi mm-mrad and was obtained with a pulse width of 5 ps (FWHM) and is in agreement with simulation. There are indications that the accelerator settings for these results may not have been optimal. Simulations also indicate that a normalized emittance meeting the LCLS requirement can be obtained using appropriately shaped transverse and temporal laser/electron beam pulses. Work has begun on producing temporal flat top laser pulses which combined with transverse clipping of the laser is expected to lower the emittance to approximately 1 pi mm-mrad for 1 nC with optimal accelerator settings.

Reis, David A

1998-12-07

339

Transverse emittance measurements from a photocathode RF gun with variable laser pulse length  

NASA Astrophysics Data System (ADS)

The gun test facility (GTF) at SSRL was started in 1996 to develop an appropriate injector for the proposed linac coherent light source (LCLS) at SLAC. The LCLS design requires the injector to produce a beam with at least 1 nC of charge in a 10 ps or shorter pulse with no greater than 1? mm mrad normalized rms emittance. The photoinjector at the GTF is 1.6 cell S-band symmetrized gun and emittance compensation solenoid. Emittance measurements, reported here, were made as function of laser pulse width using Gaussian longitudinal pulses. The lowest achieved emittance to date with 1 nC of charge is 5.6? mm mrad and was obtained with a pulse width of 5 ps (FWHM) and is in agreement with simulation. There are indications that the accelerator settings for these results may not have been optimal. Simulations also indicate that a normalized emittance meeting the LCLS requirement can be obtained using appropriately shaped transverse and temporal laser/electron beam pulses. Work has begun on producing temporal flat top laser pulses which combined with transverse clipping of the laser is expected to lower the emittance to approximately 1? mm mrad for 1 nC with optimal accelerator settings.

Reis, D. A.; Hernandez, M.; Schmerge, J. F.; Winick, H.; Hogan, M. J.

1999-06-01

340

Correlations between force plate measures for assessment of balance  

Microsoft Academic Search

Objective. To compare different force plate measures for assessment of postural stability during normal standing. Five types of measures were analysed: (1) The standard deviation of the horizontal ground reaction force, (2) the standard deviation of the centre of pressure, (3) the mean velocity of the centre of pressure, (4) movement strategy measures, and (5) the standard deviation of the

Annica Karlsson; Gunilla Frykberg

2000-01-01

341

Determination of patterns of human body measurements by use of partial correlations  

Microsoft Academic Search

From an anthropometric survey of British car drivers, matrices of correlations between body measurements have been obtained for males and females. These correlations have then been transformed into partial correlations with age, stature, and weight successively eliminated. It is argued that this process reveals patterns of body shape without the need for the complexities of more sophisticated techniques such as

T. P. HUTCHINSON; C. M. HASLEGRAVE

1980-01-01

342

Leaf vein length per unit area is not intrinsically dependent on image magnification: avoiding measurement artifacts for accuracy and precision.  

PubMed

Leaf vein length per unit leaf area (VLA; also known as vein density) is an important determinant of water and sugar transport, photosynthetic function, and biomechanical support. A range of software methods are in use to visualize and measure vein systems in cleared leaf images; typically, users locate veins by digital tracing, but recent articles introduced software by which users can locate veins using thresholding (i.e. based on the contrasting of veins in the image). Based on the use of this method, a recent study argued against the existence of a fixed VLA value for a given leaf, proposing instead that VLA increases with the magnification of the image due to intrinsic properties of the vein system, and recommended that future measurements use a common, low image magnification for measurements. We tested these claims with new measurements using the software LEAFGUI in comparison with digital tracing using ImageJ software. We found that the apparent increase of VLA with magnification was an artifact of (1) using low-quality and low-magnification images and (2) errors in the algorithms of LEAFGUI. Given the use of images of sufficient magnification and quality, and analysis with error-free software, the VLA can be measured precisely and accurately. These findings point to important principles for improving the quantity and quality of important information gathered from leaf vein systems. PMID:25096977

Sack, Lawren; Caringella, Marissa; Scoffoni, Christine; Mason, Chase; Rawls, Michael; Markesteijn, Lars; Poorter, Lourens

2014-10-01

343

Weighted network analysis of high-frequency cross-correlation measures  

NASA Astrophysics Data System (ADS)

In this paper we implement a Fourier method to estimate high-frequency correlation matrices from small data sets. The Fourier estimates are shown to be considerably less noisy than the standard Pearson correlation measures and thus capable of detecting subtle changes in correlation matrices with just a month of data. The evolution of correlation at different time scales is analyzed from the full correlation matrix and its minimum spanning tree representation. The analysis is performed by implementing measures from the theory of random weighted networks.

Iori, Giulia; Precup, Ovidiu V.

2007-03-01

344

Correlations among measures of bladder function and comfort.  

PubMed

There is a need for standard functional and psychosocial measurements of compromised urinary bladder syndrome (CUBS). Utilizing Kolcaba's Comfort Theory, the purpose of this study was to assess the psychometric properties and relationships among 8 measures of comfort, status of urinary frequency and incontinence, and quality of life. A convenience sample of 47 persons (45 women, 2 men) ages 25 to 92, who had UI for more than 6 months, was recruited. Data were collected twice with a 2-week interval. We examined (a) 1 measure of the immediate outcome of comfort related to CUBS, (b) 5 measures of UI status, and (c) 2 measures of quality of life. Reliabilities were adequate for all measures. Relationships among variables are presented and discussed. Recommendations are made for measures that detect improvement over time related to first line interventions. PMID:12048966

Dowd, Thérèse; Kolcaba, Katherine; Steiner, Richard

2002-01-01

345

Correlation Between Immersion Profile and Measured Value of Fixed-Point Temperature  

NASA Astrophysics Data System (ADS)

Assessment of thermal immersion effects in the melting and freezing points defined by the International Temperature Scale of 1990 is one of the vital issues of modern thermometry. In documents of the Consultative Committee for Thermometry, the deviation of the experimental immersion profile from the theoretical value of the hydrostatic effect at a height of about 3 cm to 5 cm from the thermometer well bottom is used for the estimation of the uncertainty due to unwanted thermal effects. This estimation assumes the occurrence of solely the hydrostatic effect all along the height of the well inner wall. Real distortions of the temperature gradient at the bottom and at the top part of the well caused by the change of heat-exchange conditions are not taken into account. To define more precisely the temperature gradient along the height of the well, a miniature PRT with a 30 mm sensitive element and a sheath length and diameter of about 60 mm and 6 mm, respectively, were used. Also, the measurements of fixed-points temperature at noticeably different slopes of immersion profiles due to variations of the thermometer heat exchange and phase transition realization conditions were produced by means of a standard platinum resistance thermometer (SPRT). The measurements were carried out at the tin and zinc freezing points. The immersion curves measured with a miniature thermometer demonstrated an increase of the temperature during its lifting in the first 1 cm to 3 cm above the bottom of the well. The measurement results at the zinc freezing point by means of the SPRT have not confirmed the correlation between the immersion curves, the received value of the Zn freezing temperature, and the estimation of its uncertainty.

Shulgat, O. S.; Fuksov, V. M.; Ivanova, A. G.; Gerasimov, S. F.; Pokhodun, A. I.

2014-04-01

346

23 CFR Appendix D to Part 658 - Devices That Are Excluded From Measurement of the Length or Width of a Commercial Motor Vehicle  

Code of Federal Regulations, 2012 CFR

...Measurement of the Length or Width of a Commercial Motor Vehicle D Appendix D to Part 658 Highways FEDERAL HIGHWAY ADMINISTRATION...DESIGNATIONS-LENGTH, WIDTH AND WEIGHT LIMITATIONS Pt. 658, App. D Appendix D to Part 658—Devices That Are Excluded...

2012-04-01

347

23 CFR Appendix D to Part 658 - Devices That Are Excluded From Measurement of the Length or Width of a Commercial Motor Vehicle  

Code of Federal Regulations, 2013 CFR

...Measurement of the Length or Width of a Commercial Motor Vehicle D Appendix D to Part 658 Highways FEDERAL HIGHWAY ADMINISTRATION...DESIGNATIONS-LENGTH, WIDTH AND WEIGHT LIMITATIONS Pt. 658, App. D Appendix D to Part 658—Devices That Are Excluded...

2013-04-01

348

Joint radius-length distribution as a measure of anisotropic pore eccentricity: An experimental and analytical framework  

NASA Astrophysics Data System (ADS)

In this work, we present an experimental design and analytical framework to measure the nonparametric joint radius-length (R-L) distribution of an ensemble of parallel, finite cylindrical pores, and more generally, the eccentricity distribution of anisotropic pores. Employing a novel 3D double pulsed-field gradient acquisition scheme, we first obtain both the marginal radius and length distributions of a population of cylindrical pores and then use these to constrain and stabilize the estimate of the joint radius-length distribution. Using the marginal distributions as constraints allows the joint R-L distribution to be reconstructed from an underdetermined system (i.e., more variables than equations), which requires a relatively small and feasible number of MR acquisitions. Three simulated representative joint R-L distribution phantoms corrupted by different noise levels were reconstructed to demonstrate the process, using this new framework. As expected, the broader the peaks in the joint distribution, the less stable and more sensitive to noise the estimation of the marginal distributions. Nevertheless, the reconstruction of the joint distribution is remarkably robust to increases in noise level; we attribute this characteristic to the use of the marginal distributions as constraints. Axons are known to exhibit local compartment eccentricity variations upon injury; the extent of the variations depends on the severity of the injury. Nonparametric estimation of the eccentricity distribution of injured axonal tissue is of particular interest since generally one cannot assume a parametric distribution a priori. Reconstructing the eccentricity distribution may provide vital information about changes resulting from injury or that occurred during development.

Benjamini, Dan; Basser, Peter J.

2014-12-01

349

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

350

Soot particle size distribution measurements in a premixed flame using photon correlation spectroscopy  

Microsoft Academic Search

We have measured the first two moments of the soot particle size distribution in premixed methane\\/oxygen flames using the dynamic light scattering technique, photon correlation spectroscopy. Measurements were performed in a flat flame burner as a function of fuel-oxidizer equivalence ratio and height above burner. We demonstrated the ability of photon correlation spectroscopy to extract two moments, the most probable

S. M. Scrivner; T. W. Taylor; C. M. Sorensen; J. F. Merklin

1986-01-01

351

The Concordance Correlation Coefficient for Repeated Measures Estimated by Variance Components  

Microsoft Academic Search

The concordance correlation coefficient (CCC) is an index that is commonly used to assess the degree of agreement between observers on measuring a continuous characteristic. Here, a CCC for longitudinal repeated measurements is developed through the appropriate specification of the intraclass correlation coefficient from a variance components linear mixed model. A case example and the results of a simulation study

Josep L. Carrasco; Tonya S. King; Vernon M. Chinchilli

2009-01-01

352

The Correlation Among Factors Related to Measuring Ability.  

ERIC Educational Resources Information Center

Factors affecting measuring ability in machine shop practices at the high school level were investigated. A sample of 157 male students enrolled at four metropolitan high schools in Chicago was administered four tests devised specifically for this study (one each on measuring ability, numerical ability, mechanical knowledge, and kinesthetic…

Shih, Wei-tun

353

A new Doppler imaging measurement in aortic stenosis: the contour length of the jet origin flow area. Relationships between both, with usual Doppler data and left ventricular hypertrophy.  

PubMed

Planimetry of stenotic aortic jet origin flow areas was performed using transthoracic Doppler imaging, with measurement of the contour length of flow areas and calculation of a contour/area (C/A) Doppler ratio on a group of 75 patients with aortic stenosis ranging from 0.27 to 2.44 cm2. The purpose was to study correlations of these data with the usual Doppler data and with left ventricular hypertrophy. The "r" coefficient between planimetered flow areas and those calculated by the continuity equation method was 0.89. Mean values (SD) of data were: areas: (planimetry) 1.00 +/- 0.53 cm2, (continuity equation) 0.91 +/- 0.42 cm2, contours: 5.6 +/- 1.6 cm, C/A: 0.66 +/- 0.25, maximal and mean pressure gradients: 68 +/- 34 and 37 +/- 21 mmHg, left ventricular hypertrophy: 138 +/- 30 g/m2 BSA (vs. 100 +/- 18 in normals). All values except age, gender and BSA, differed significantly (p < 0.001) between areas below or over 0.85 cm2. Other correlations between parameters were significant (p < 0.01 to 0.001), but with lower "r" coefficients due to widely scattered individual values. Contours increased much less rapidly than areas did, and were correlated with left ventricular hypertrophy only when coupled in the C/A ratio, with a higher "r" coefficient (0.62) than areas alone (0.52). Study of both areas and contours helps to approach the geometry of the orifice. This suggests that the individual geometry of the stenosis might weigh on the left ventricular mass growth, as an associated factor for a given decrease in stenotic area. PMID:7886843

Veyrat, C; Sainte Beuve, D; el Yafi, W; Sebaoun, G; Kalmanson, D

1994-01-01

354

Measurement Uncertainty Evaluation Method Considering Correlation and its Application to Precision Centrifuge  

NASA Astrophysics Data System (ADS)

Measurement uncertainty evaluation based on the Monte Carlo method (MCM) with the assumption that all uncertainty sources are independent is common. For some measure problems, however, the correlation between input quantities is of great importance and even essential. The purpose of this paper is to provide an uncertainty evaluation method based on MCM that can handle correlated cases, especially for measurement in which uncertainty sources are correlated and submit to non-Gaussian distribution. In this method, a linear-nonlinear transformation technique was developed to generate correlated random variables sampling sequences with target prescribed marginal probability distribution and correlation coefficients. Measurement of the arm stretch of a precision centrifuge of 10-6 order was implemented by a high precision approach and associated uncertainty evaluation was carried out using the mentioned method and the method proposed in the Guide to the Expression of Uncertainty in Measurement (GUM). The obtained results were compared and discussed at last.

Ling, Mingxiang; Li, Huimin; Li, Qisheng

2014-12-01

355

Three-dimensional image correlation for surface-displacement measurement  

NASA Astrophysics Data System (ADS)

This paper describes a 3D surface profile and displacement measurement system capable of micron level accuracy using moderately priced off-the-shelf equipment. A non-linear optimization based calibration system is presented. The calibration system determines the position and operating characteristics of the cameras as well as correcting for lens distortion. Also presented is a surface profile and displacement measurement system base on projections into space of subsets of the recorded images. This method provides information about both the location and orientation in space of the subset. The accuracy of the system is established through a series of experiments. The calibration is assessed and the results are expressed using several different error measurements including a new error measurement proposed by the authors. The baseline accuracy of the measurement system was determined through a series of profile and translation tests. The system is capable of measurements to an accuracy of 0.003 mm over a 14 mm X 18 mm field from a distance of 416 mm using a 512 X 480 CCD camera and a magnification factor of 27 pixels/mm. The system was also used to measure the bending of a circular plate under pressure loading. The experimental results are analyzed and compared with theoretical prediction.

Helm, Jeffrey D.; Sutton, Michael A.; McNeill, Stephen R.

1994-10-01

356

Shrinkage of dental composite in simulated cavity measured with digital image correlation.  

PubMed

Polymerization shrinkage of dental resin composites can lead to restoration debonding or cracked tooth tissues in composite-restored teeth. In order to understand where and how shrinkage strain and stress develop in such restored teeth, Digital Image Correlation (DIC) was used to provide a comprehensive view of the displacement and strain distributions within model restorations that had undergone polymerization shrinkage. Specimens with model cavities were made of cylindrical glass rods with both diameter and length being 10 mm. The dimensions of the mesial-occlusal-distal (MOD) cavity prepared in each specimen measured 3 mm and 2 mm in width and depth, respectively. After filling the cavity with resin composite, the surface under observation was sprayed with first a thin layer of white paint and then fine black charcoal powder to create high-contrast speckles. Pictures of that surface were then taken before curing and 5 min after. Finally, the two pictures were correlated using DIC software to calculate the displacement and strain distributions. The resin composite shrunk vertically towards the bottom of the cavity, with the top center portion of the restoration having the largest downward displacement. At the same time, it shrunk horizontally towards its vertical midline. Shrinkage of the composite stretched the material in the vicinity of the "tooth-restoration" interface, resulting in cuspal deflections and high tensile strains around the restoration. Material close to the cavity walls or floor had direct strains mostly in the directions perpendicular to the interfaces. Summation of the two direct strain components showed a relatively uniform distribution around the restoration and its magnitude equaled approximately to the volumetric shrinkage strain of the material. PMID:25079865

Li, Jianying; Thakur, Preetanjali; Fok, Alex S L

2014-01-01

357

TURBULENT DYNAMICS IN SOLAR FLARE SHEET STRUCTURES MEASURED WITH LOCAL CORRELATION TRACKING  

SciTech Connect

High-resolution observations of the Sun's corona in extreme ultraviolet and soft X-rays have revealed a new world of complexity in the sheet-like structures connecting coronal mass ejections (CMEs) to the post-eruption flare arcades. This article presents initial findings from an exploration of dynamic flows in two flares observed with Hinode/XRT and SDO/AIA. The flows are observed in the hot ({approx}> 10 MK) plasma above the post-eruption arcades and measured with local correlation tracking. The observations demonstrate significant shears in velocity, giving the appearance of vortices and stagnations. Plasma diagnostics indicate that the plasma {beta} exceeds unity in at least one of the studied events, suggesting that the coronal magnetic fields may be significantly affected by the turbulent flows. Although reconnection models of eruptive flares tend to predict a macroscopic current sheet in the region between the CME and the flare arcade, it is not yet clear whether the observed sheet-like structures are identifiable as the current sheets or 'thermal halos' surrounding the current sheets. Regardless, the relationship between the turbulent motions and the embedded magnetic field is likely to be complicated, involving dynamic fluid processes that produce small length scales in the current sheet. Such processes may be crucial for triggering, accelerating, and/or prolonging reconnection in the corona.

McKenzie, D. E., E-mail: mckenzie@physics.montana.edu [Department of Physics, Montana State University, P.O. Box 173840, Bozeman, MT 59717-3840 (United States)

2013-03-20

358

Plan View and Profile Relations: Measuring Correlation Between Channel Profile and Network Morphology  

NASA Astrophysics Data System (ADS)

In this research, we explore the relationships between channel network attributes and the corresponding channel profile geometries using high-resolution digital topography and model-generated synthetic topographies. This combined analysis addresses one of the long-standing questions in geomorphology relating to the mechanistic significance of various plan-view channel network geometry measures. Statistically based numerical studies suggest that Hortonian measures of channel network architecture (e.g. bifurcation ratio, area ratio, and length ratio) describe virtually all possible network geometries, and so are not diagnostic when evaluating the origins of the geometry of a particular network. We further explore this hypothesis by examining the correlation between Hack exponent, the channel profile characteristics, and process changes (i.e debris flow vs. fluvial flows) within the landscape. Analysis of high resolution DEMs as well as modeled landscapes, suggests that the Hack exponent is likewise insensitive to changes in the channel profile concavity. In contrast, we find that changes in the concavity of channel profiles apparently impacts the spatial distribution of plan-view junction angles of joining stream segments throughout a catchment. In the context of previous work, this angle might be expected to be a function of the ratio between the slopes of the adjoined channels. Channel concavity determines downstream change in this ratio for channel segments throughout the basin, and so such a metric might be used to explicitly link profile channel geometries to plan-view network geometries. Because profile geometries may change with different advective mass transport processes, such a metric may provide a link between the processes that transport material across a landscape, the profile geometry of channels through which these flows traverse, and the overall drainage network geometry. Additional numerical and field data based analysis are required to further explore the sensitivity of the junction angle, as well as other measures, to process changes along the channel network.

Shelef, E.; Hilley, G. E.

2010-12-01

359

Extraction of the neutron-electron scattering length from the neutron diffraction data measured on noble gases  

NASA Astrophysics Data System (ADS)

A new method of extracting the neutron-electron scattering length b, which is directly connected with the fundamental physical value of neutron mean squared charge radius, from the slow neutron diffraction on noble gases was developed and verified by the analysis of literature data on structure factors for gaseous Kr and 36Ar and for liquid Kr. Different variants of analysis of these experimental data allow us to obtain b value with the statistical accuracy of 10-20%, but in some of them the real possibility for the accessible accuracy no worse than 2-3% was shown. In order to remove some systematical uncertainties and to reach such a good accuracy the execution of comparative diffraction measurements is proposed with a pair of gases having close atomic properties and different n,e-scattering contributions, such as Ar- 36Ar or Xe-Kr.

Mitsyna, L. V.; Nikolenko, V. G.; Parzhitski, S. S.; Popov, A. B.; Samosvat, G. S.

2009-03-01

360

Assessing the length of the mandibular ramus and the condylar process: a comparison of OPG, CBCT, CT, MRI, and lateral cephalometric measurements.  

PubMed

Summary Background/Objectives: To compare different imaging procedures [cone beam computed tomography (CBCT), computed tomography (CT), magnetic resonance imaging (MRI), orthopantomography (OPG), and lateral cephalometry (LC)] for assessing the mandibular height [ramus height (RH)] and condylar process (CondProc) length as they reflect mandibular growth. Materials/Methods: The RH and CondProc of eight cadaver heads (each side separately) were measured using CBCT, CT, MRI, OPG, and LC. They were measured twice by two independent observers parallel to the posterior border of the mandibular ramus. An intraclass correlation coefficient (ICC) was used to assess the inter- and intraobserver reliability. The coefficient of variation was used to elucidate precision. Bland-Altman (BA) plots were used to assess the agreement between the procedures and the intra- and interobserver measurements. Results: All procedures, with the exception of LC, showed good intra- and interobserver agreement (maximum range of agreement: 5.3mm) and excellent reliability (ICC > 0.9). The BA plot analysis for the CondProc and RH showed similar ranges of agreement between MRI, CT, and CBCT (maximum 6.4mm) but higher ranges for OPG and LC. The MRI and OPG values were generally smaller. Conclusions/Implications: All 3D imaging procedures yielded nearly equal results when used to measure the CondProc and RH. MRI is recommended because it avoids ionizing radiation and has higher sensitivity in the detection of inflammation. A 2-year threshold for detecting growth in the follow-up period should be taken into account for all 3D imaging methods. Measuring the RH is recommended for the follow-up of condylar growth because reference values for annual increments are published. PMID:25154725

Markic, Goran; Müller, Lukas; Patcas, Raphael; Roos, Malgorzata; Lochbühler, Nina; Peltomäki, Timo; Karlo, Christoph A; Ullrich, Oliver; Kellenberger, Christian J

2014-08-25

361

Safety, Feasibility and Reliability of the Maximal Step Length, Gait Speed and Chair Test Measured by Seniors Themselves: The Senior Step Study.  

PubMed

Self-management of mobility and fall risk might be possible if older adults could use a simple and safe self-test to measure their own mobility, balance and fall risk at home. The aim of this study was to determine the safety, feasibility and intra-individual reliability of the Maximal Step Length (MSL), Gait Speed (GS) and Chair Test (CT) as potential self-tests for assessing mobility and fall risk. Fifty-six community-dwelling older adults performed MSL, GS and CT at home once a week during a four-week period, wherein the feasibility, test-retest reliability, coefficients of variation and linear mixed models with random effects of these three self-tests were determined. Forty-nine subjects (mean age 76.1 yrs (SD: 4.0), 19 females (42%)) completed the study without adverse effects. Compared with the other self-tests, MSL gave most often (77.6%) valid measurement results and had the best intraclass correlation coefficients (0.95 (95% confidence interval: 0.91-0.97). MSL and GS gave no significant training effect, whereas CT did show a significant training effect (p<0.01). Community-dwelling older adults can perform MSL safely, correctly and reliably, and GS safely and reliably. Further research is needed to study the responsiveness and beneficial effects of these self-tests on self-management of mobility and fall risk. PMID:25342646

Bongers, Kim T; Schoon, Yvonne; Graauwmans, Maartje J; Hoogsteen-Ossewaarde, Marlies E; Olde Rikkert, Marcel G

2014-10-23

362

Measurements of neutron effective doses and attenuation lengths for shielding materials at the heavy-ion medical accelerator in Chiba.  

PubMed

The effective doses and attenuation lengths for concrete and iron were measured for the design of heavy ion facilities. Neutrons were produced through the reaction of copper, carbon, and lead bombarded by carbon ions at 230 and 400 MeV.A, neon ions at 400 and 600 MeV.A, and silicon ions at 600 and 800 MeV.A. The detectors used were a Linus and a Andersson-Braun-type rem counter and a detector based on the activation of a plastic scintillator. Representative effective dose rates (in units of 10(-8) microSv h(-1) pps(-1) at 1 m from the incident target surface, where pps means particles per second) and the attenuation lengths (in units of m) were 9.4 x 10(4), 0.46 for carbon ions at 230 MeV.A; 8.9 x 10(5), 0.48 for carbon ions at 400 MeV.A; 9.3 x 10(5), 0.48 for neon ions at 400 MeV.A; 3.8 x 10(6), 0.50 for neon ions at 600 MeV.A; 3.9 x 10(6), 0.50 for silicon ions at 600 MeV.A; and 1.1 x 10(7), 0.51 for silicon ions at 800 MeV.A. The attenuation provided by an iron plate approximately 20 cm thick (nearly equal to the attenuation length) corresponded to that of a 50-cm block of concrete in the present energy range. Miscellaneous results, such as the angular distributions of the neutron effective dose, narrow beam attenuation experiments, decay of gamma-ray doses after the bombardment of targets, doses around an irradiation room, order effects in the multi-layer (concrete and iron) shielding, the doses from different targets, the doses measured with a scintillator activation detector, the gamma-ray doses out of walls and the ratio of the response between the Andersson-Braun-type and the Linus rem counters are also reported. PMID:15824595

Kumamoto, Yoshikazu; Noda, Yutaka; Sato, Yukio; Kanai, Tatsuaki; Murakami, Takeshi

2005-05-01

363

Neutron and gamma-ray cross-correlation measurements of plutonium oxide powder  

NASA Astrophysics Data System (ADS)

For the first time, measurements of the time-dependent cross-correlation distributions of plutonium oxide have been made separately for neutrons and gamma rays. Six EJ-309 liquid scintillation detectors with a digital, offline pulse shape discrimination and pulse timing method were used to measure five different samples of varying mass and burnup. The number of (neutron, neutron) correlations were selectively analyzed versus plutonium mass and a clear, increasing trend was observed. Additionally, the measurement scenarios were modeled using the MCNP-PoliMi code and good agreement was observed between the measured and simulated cross-correlation functions.

Clarke, S. D.; Flaska, M.; Pozzi, S. A.; Peerani, P.

2009-06-01

364

Measurement of reaction plane correlations in Pb-Pb collisions with the ATLAS detector  

NASA Astrophysics Data System (ADS)

Recently flow harmonics v1 - v6 have been measured in heavy-ion collisions at the LHC. The magnitude of these coefficients and their centrality dependence suggest that they are associated with the various shape components in the initial geometry. The phases of these harmonics (reaction plane angles, ?n) are generally correlated due to the correlations between the original shape components in the initial geometry; the correlations between reaction planes might also be generated dynamically during the hydrodynamic evolution of the medium. We present first measurements of various reaction plane correlations involving ?2 to ?6 in Pb-Pb collisions using the ATLAS detector at the LHC. The large acceptance of the ATLAS EM calorimeters, covering 4.9measurement of these correlations. The procedure for obtaining these correlations and the physics implication of the results are discussed.

Mohapatra, Soumya

2013-05-01

365

Effect of Crystal Defects on Minority Carrier Diffusion Length in 6H SiC Measured Using the Electron Beam Induced Current Method  

NASA Technical Reports Server (NTRS)

We report values of minority carrier diffusion length in n-type 6H SiC measured using a planar Electron Beam Induced Current (EBIC) method. Values of hole diffusion length in defect free regions of n-type 6H SiC, with a doping concentration of 1.7El7 1/cu cm, ranged from 1.46 microns to 0.68 microns. We next introduce a novel variation of the planar method used above. This 'planar mapping' technique measured diffusion length along a linescan creating a map of diffusion length versus position. This map is then overlaid onto the EBIC image of the corresponding linescan, allowing direct visualization of the effect of defects on minority carrier diffusion length. Measurements of the above n-type 6H SiC resulted in values of hole diffusion length ranging from 1.2 micron in defect free regions to below 0.1 gm at the center of large defects. In addition, measurements on p-type 6H SiC resulted in electron diffusion lengths ranging from 1.42 micron to 0.8 micron.

Tabib-Azar, Massood

1997-01-01

366

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

367

LOCAL STRAIN AND DAMAGE MEASUREMENTS ON A COMPOSITE WITH DIGITAL IMAGE CORRELATION AND ACOUSTIC EMISSION  

E-print Network

LOCAL STRAIN AND DAMAGE MEASUREMENTS ON A COMPOSITE WITH DIGITAL IMAGE CORRELATION AND ACOUSTIC of each part is essential. To obtain the stress/strain relations strain measurements are conducted be measured simultaneously. To measure strain many techniques can be used (extensometers, strain gauges

Boyer, Edmond

368

Measuring blood velocity using correlative spectrally encoded flow cytometry.  

PubMed

Spectrally encoded flow cytometry (SEFC) is a promising technique for imaging blood in the microcirculation. Yet, the dependency of one of the axes of the image on time prevents effective quantification of essential clinical parameters. Here, we address this challenge by splitting the optical path in an SEFC system into two parallel imaging lines, followed by straightforward data analysis for recovering the flow speed from the multiplexed data. The method is demonstrated by measuring the flow velocity of latex beads and blood cells in vitro. The system allows real-time velocity measurements of up to 11.7??mm/s at high spatial resolution, and could be integrated into existing SEFC systems for effectively measuring blood parameters in small capillary vessels. PMID:25078193

Elhanan, Tal; Yelin, Dvir

2014-08-01

369

Ultrasonic velocity measurement using phase-slope cross-correlation methods  

NASA Technical Reports Server (NTRS)

Computer implemented phase-slope and cross-correlation methods are introduced for measuring time delays between pairs of broadband ultrasonic pulse-echo signals for determining velocity in engineering materials. The phase-slope and cross-correlation methods are compared with the overlap method which is currently in wide use. Comparison of digital versions of the three methods shows similar results for most materials having low ultrasonic attenuation. However, the cross-correlation method is preferred for highly attenuating materials. An analytical basis for the cross-correlation method is presented. Examples are given for the three methods investigated to measure velocity in representative materials in the megahertz range.

Hull, D. R.; Kautz, H. E.; Vary, A.

1984-01-01

370

Impulsive noise of printers: measurement metrics and their subjective correlation  

Microsoft Academic Search

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

Terrence Baird; Norman Otto; Wade Bray; Mike Stephan

2005-01-01

371

Correlation of Scan and Sample Measurements Using Appropriate Sample Size  

Microsoft Academic Search

At a former nuclear fuel cycle facility, radiological site characterization performed in the 1990's relied on surface soil samples collected and analyzed on a systematic sampling grid, supplemented by 100% scans of the property to identify soil exceeding decommissioning criteria. Biased sampling was performed as indicated by these measurements to provide more precise delineation of material exceeding the decommissioning criteria

Lux

2008-01-01

372

Defect printability measurement on the KLA-351: correlation to defect sizing using the AVI metrology system  

NASA Astrophysics Data System (ADS)

The search for the 'holy grail' of a fast, reliable, inexpensive predictor of defect printability has reached a new level. Taking images from several inspection tools (KLA-351, KLA-353, and KLA Starlight) during defect review, the AVI Photomask Metrology System provides measurement repeatability better than 5 nm, and significantly better correlation to printability than Scanning Electron Microscope (SEM) measurements. SEM measurements of printed defects are compared to various measurements of the defects on the mask. Analysis shows, as expected, that optical area measurements provide the best correlation to printability. Further, images from existing inspection tools are shown to be sufficient to produce these measurements using AVI's new 'Flux-area' technique.

Fiekowsky, Peter; Selassie, Daniel

1999-12-01

373

Comparison of co-expression measures: mutual information, correlation, and model based indices  

PubMed Central

Background Co-expression measures are often used to define networks among genes. Mutual information (MI) is often used as a generalized correlation measure. It is not clear how much MI adds beyond standard (robust) correlation measures or regression model based association measures. Further, it is important to assess what transformations of these and other co-expression measures lead to biologically meaningful modules (clusters of genes). Results We provide a comprehensive comparison between mutual information and several correlation measures in 8 empirical data sets and in simulations. We also study different approaches for transforming an adjacency matrix, e.g. using the topological overlap measure. Overall, we confirm close relationships between MI and correlation in all data sets which reflects the fact that most gene pairs satisfy linear or monotonic relationships. We discuss rare situations when the two measures disagree. We also compare correlation and MI based approaches when it comes to defining co-expression network modules. We show that a robust measure of correlation (the biweight midcorrelation transformed via the topological overlap transformation) leads to modules that are superior to MI based modules and maximal information coefficient (MIC) based modules in terms of gene ontology enrichment. We present a function that relates correlation to mutual information which can be used to approximate the mutual information from the corresponding correlation coefficient. We propose the use of polynomial or spline regression models as an alternative to MI for capturing non-linear relationships between quantitative variables. Conclusion The biweight midcorrelation outperforms MI in terms of elucidating gene pairwise relationships. Coupled with the topological overlap matrix transformation, it often leads to more significantly enriched co-expression modules. Spline and polynomial networks form attractive alternatives to MI in case of non-linear relationships. Our results indicate that MI networks can safely be replaced by correlation networks when it comes to measuring co-expression relationships in stationary data. PMID:23217028

2012-01-01

374

Measurements of angular correlations in electron impact inner-shell ionisation  

Microsoft Academic Search

The first measurements of the angular correlation between a scattered electron which has ejected a bound electron from an inner atomic shell and one of the decay products of the ion formed are presented. Ionisation of the 2p3\\/2 shell of argon has been studied by measuring the angular correlation between the scattered electron and the L3-M23M23(1S0) Auger electron. The measured

E. C. Sewell; A. Crowe

1982-01-01

375

Rapid, Accurate, and Non-Invasive Measurement of Zebrafish Axial Length and Other Eye Dimensions Using SD-OCT Allows Longitudinal Analysis of Myopia and Emmetropization  

PubMed Central

Refractive errors in vision can be caused by aberrant axial length of the eye, irregular corneal shape, or lens abnormalities. Causes of eye length overgrowth include multiple genetic loci, and visual parameters. We evaluate zebrafish as a potential animal model for studies of the genetic, cellular, and signaling basis of emmetropization and myopia. Axial length and other eye dimensions of zebrafish were measured using spectral domain-optical coherence tomography (SD-OCT). We used ocular lens and body metrics to normalize and compare eye size and relative refractive error (difference between observed retinal radial length and controls) in wild-type and lrp2 zebrafish. Zebrafish were dark-reared to assess effects of visual deprivation on eye size. Two relative measurements, ocular axial length to body length and axial length to lens diameter, were found to accurately normalize comparisons of eye sizes between different sized fish (R2?=?0.9548, R2?=?0.9921). Ray-traced focal lengths of wild-type zebrafish lenses were equal to their retinal radii, while lrp2 eyes had longer retinal radii than focal lengths. Both genetic mutation (lrp2) and environmental manipulation (dark-rearing) caused elongated eye axes. lrp2 mutants had relative refractive errors of ?0.327 compared to wild-types, and dark-reared wild-type fish had relative refractive errors of ?0.132 compared to light-reared siblings. Therefore, zebrafish eye anatomy (axial length, lens radius, retinal radius) can be rapidly and accurately measured by SD-OCT, facilitating longitudinal studies of regulated eye growth and emmetropization. Specifically, genes homologous to human myopia candidates may be modified, inactivated or overexpressed in zebrafish, and myopia-sensitizing conditions used to probe gene-environment interactions. Our studies provide foundation for such investigations into genetic contributions that control eye size and impact refractive errors. PMID:25334040

Collery, Ross F.; Veth, Kerry N.; Dubis, Adam M.; Carroll, Joseph; Link, Brian A.

2014-01-01

376

Kronecker Product Linear Exponent AR(1) Correlation Structures for Multivariate Repeated Measures  

PubMed Central

Longitudinal imaging studies have moved to the forefront of medical research due to their ability to characterize spatio-temporal features of biological structures across the lifespan. Credible models of the correlations in longitudinal imaging require two or more pattern components. Valid inference requires enough flexibility of the correlation model to allow reasonable fidelity to the true pattern. On the other hand, the existence of computable estimates demands a parsimonious parameterization of the correlation structure. For many one-dimensional spatial or temporal arrays, the linear exponent autoregressive (LEAR) correlation structure meets these two opposing goals in one model. The LEAR structure is a flexible two-parameter correlation model that applies to situations in which the within-subject correlation decreases exponentially in time or space. It allows for an attenuation or acceleration of the exponential decay rate imposed by the commonly used continuous-time AR(1) structure. We propose the Kronecker product LEAR correlation structure for multivariate repeated measures data in which the correlation between measurements for a given subject is induced by two factors (e.g., spatial and temporal dependence). Excellent analytic and numerical properties make the Kronecker product LEAR model a valuable addition to the suite of parsimonious correlation structures for multivariate repeated measures data. Longitudinal medical imaging data of caudate morphology in schizophrenia illustrates the appeal of the Kronecker product LEAR correlation structure. PMID:24586419

Simpson, Sean L.; Edwards, Lloyd J.; Styner, Martin A.; Muller, Keith E.

2014-01-01

377

Local compressibility measurements of correlated states in suspended bilayer graphene.  

PubMed

Bilayer graphene has attracted considerable interest due to the important role played by many-body effects, particularly at low energies. Here we report local compressibility measurements of a suspended graphene bilayer. We find that the energy gaps at filling factors ?= ± 4 do not vanish at low fields, but instead merge into an incompressible region near the charge neutrality point at zero electric and magnetic field. These results indicate the existence of a zero-field ordered state and are consistent with the formation of either an anomalous quantum Hall state or a nematic phase with broken rotational symmetry. At higher fields, we measure the intrinsic energy gaps of broken-symmetry states at ?=0, ± 1, and ± 2, and find that they scale linearly with magnetic field, yet another manifestation of the strong Coulomb interactions in bilayer graphene. PMID:21231612

Martin, J; Feldman, B E; Weitz, R T; Allen, M T; Yacoby, A

2010-12-17

378

Spot size and effective focal length measurements for a fast axial flow CO{sub 2} laser  

SciTech Connect

An evaluation of the variation in focal plane position and spot size for a 1,650 W fast axial flow CO{sub 2} laser was performed. Multiple measurements of the focused beam were taken at stepped intervals along the beam axis to create a composite representation of the focus region. Measurements were made at several power levels from low to full power for each of five nominally identical lenses. It was found that as laser output power increases, the minimum focused spot radius increases, and the position of minimum focus shifts toward the laser resonator. These effects were attributed to observed variations in the diameter of the beam entering the focusing lens. For the ZnSe (f = 127 mm) lenses examined, variations in spot radius and focal plane position were seen. Lenses with high rated absorption had a larger variation in spot size and effective focal length than those with low absorption. Lenses that had previously been degraded by welding had the greatest variation.

Steele, R.J. [Naval Air Warfare Center, China Lake, CA (United States); Fuerschbach, P.W.; MacCallum, D.O. [Sandia National Labs., Albuquerque, NM (United States)

1997-12-31

379

On using the levelling of the free surface of a Newtonian fluid to measure viscosity and Navier slip length  

PubMed Central

Measuring the relaxation time involved in the levelling of a free surface of a Newtonian fluid laid on a substrate can give access to material parameters. It is shown here how most favourable pattern geometries of the free surface and film thicknesses can be defined for the measures of viscosity and Navier slip length at the fluid–solid interface, respectively. Moreover, we put special emphasis on the conditions required to avoid shear thinning by controlling the maximum shear rate. For initially sinusoidal patterns with infinitesimal amplitudes, an analytical solution including slip at the fluid–solid interface is used, and numerical simulations based on the natural element method allow one to discuss the effect of finite amplitudes. This leads to the definition of a relevance domain for the analytical solution that avoids the need for numerical simulations in practical applications. It is also shown how these results can be applied to crenelated profiles, where Fourier series expansion can be used, but with caution. PMID:24353474

Gilormini, P.; Teyssèdre, H.

2013-01-01

380

Expression of Telomeres in Astrocytoma WHO Grade 2 to 4: TERRA Level Correlates with Telomere Length, Telomerase Activity, and Advanced Clinical Grade12  

PubMed Central

Cancer cells bypass replicative senescence, the major barrier to tumor progression, by using telomerase or alternative lengthening of telomeres (ALT) as telomere maintenance mechanisms (TMMs). Correlation between ALT and patient survival was demonstrated for high-grade astrocytomas. Transcription from subtelomeres produces telomeric repeat-containing RNA (TERRA), a natural inhibitor of telomerase activity (TA). This led us to evaluate correlations of TERRA and TMM with tumor grade and outcome in astrocytoma patients. SYBR Green real-time reverse transcription-polymerase chain reaction assays for quantitation of total and chromosome 2p and 18p specific TERRA levels were developed. Tumor samples from 46 patients with astrocytoma grade 2 to 4, tissue controls, and cell lines were assessed. TMMs were evaluated by measuring TA and by detecting long telomeres due to ALT. In glioblastoma multiforme (GBM) grade 4, total TERRA levels were similar to cell lines but 14-, 31-, and 313-fold lower compared with grade 3, grade 2, and nonmalignant tissue, respectively. Total TERRA levels differed from chromosomal levels. Low 2p TERRA levels correlated with dense promoter methylation of subtelomeric CpG islands, indicating that TERRA expression in gliomas may be chromosome specific and epigenetically regulated. Total TERRA levels correlated with diagnosis, with low or absent TA and the presence of ALT, and were tentatively associated with favorable patient prognosis in our cohort (P = .06). TA and short telomeres identified a subset of GBM with a median survival of only 14.8 months. TERRA and TA may be prognostic in astrocytic tumors. PMID:22348177

Sampl, Sandra; Pramhas, Sibylle; Stern, Christian; Preusser, Matthias; Marosi, Christine; Holzmann, Klaus

2012-01-01

381

Imaging of adult flatfoot: correlation of radiographic measurements with MRI.  

PubMed

OBJECTIVE. The purpose of this study is to determine whether radiographic foot measurements can predict injury of the posterior tibial tendon (PTT) and the supporting structures of the medial longitudinal arch as diagnosed on MRI. MATERIALS AND METHODS. After institutional review board approval, 100 consecutive patients with radiographic and MRI examinations performed within a 2-month period were enrolled. Thirty-one patients had PTT dysfunction clinically, and 69 patients had other causes of ankle pain. Talonavicular uncoverage angle, incongruency angle, calcaneal pitch angle, Meary angle, cuneiform-to-fifth metatarsal height, and talar tilt were calculated on standing foot or ankle radiographs. MRI was used to assess for abnormalities of the PTT (tenosynovitis, tendinosis, and tear) and supporting structures of the medial longitudinal arch (spring ligament, deltoid ligament, and sinus tarsi). Statistical analysis was performed using the chi-square and Fisher exact tests for categoric variables; the Student t test was used for continuous variables. RESULTS. There was a statistically significant association of PTT tear with abnormal talonavicular uncoverage angle, calcaneal pitch angle, Meary angle, and cuneiform-to-fifth metatarsal height. PTT tendinosis and isolated tenosynovitis had a poor association with most radiologic measurements. If both calcaneal pitch and Meary angles were normal, no PTT tear was present. An abnormal calcaneal pitch angle had the best association with injury to the supporting medial longitudinal arch structures. CONCULSION. Radiographic measurements, especially calcaneal pitch and Meary angles, can be useful in detecting PTT tears. Calcaneal pitch angle provides the best assessment of injury to the supporting structures of the medial longitudinal arch. PMID:25615758

Lin, Yu-Ching; Mhuircheartaigh, Jennifer Ni; Lamb, Joshua; Kung, Justin W; Yablon, Corrie M; Wu, Jim S

2015-02-01

382

Expectations for dihadron correlation measurements at the LHC  

Microsoft Academic Search

The suppression of high transverse momentum (P_T) inclusive hadron spectra in\\u000aheavy-ion collisions as compared to the scaled expectation of high P_T hadron\\u000aproduction in p-p collisions is the most direct manifestation of the\\u000ainteraction of hard partons with the soft bulk medium produced in heavy-ion\\u000acollisions which is absent in p-p collisions. Yet the measured nuclear\\u000asuppression factor R_AA

Thorsten Renkand; Kari J. Eskola

2007-01-01

383

Correlation between precision gravity and subsidence measurements at Cerro Prieto  

NASA Astrophysics Data System (ADS)

Precision gravity measurements were made in the region of the Cerro Prieto geothermal field at yearly intervals from 1977 to 1981 to assess the feasibility of using gravity to determine subsurface reservoir changes with time. The extent of mass recharge in response to the continued production of fluids from this field was studied. Changes in gravity and ground elevation were observed throughout the region for the period of observation. Results indicate that the largest changes observed were the result of the Magnitude 6.1 (Caltech) Victoria earthquake of 8 June 1980. The epicenter of this earthquake was located 25 km southeast of the field on the Cerro Prieto Fault, which bounds the field on the southwest. Subsidence of up to 55 cm was measured east of the power plant, in the region between the northern end of the Cerro Prieto Fault and the southern end of the Imperial Fault. This area has been postulated to be the site of an active spreading center or pull-apart basin, and has been characterized by a high level of seismic activity during the last 10 years.

Zelwer, R.; Grannell, R. B.

1982-10-01

384

Reliability measures in item response theory: Manifest versus latent correlation functions.  

PubMed

For item response theory (IRT) models, which belong to the class of generalized linear or non-linear mixed models, reliability at the scale of observed scores (i.e., manifest correlation) is more difficult to calculate than latent correlation based reliability, but usually of greater scientific interest. This is not least because it cannot be calculated explicitly when the logit link is used in conjunction with normal random effects. As such, approximations such as Fisher's information coefficient, Cronbach's ?, or the latent correlation are calculated, allegedly because it is easy to do so. Cronbach's ? has well-known and serious drawbacks, Fisher's information is not meaningful under certain circumstances, and there is an important but often overlooked difference between latent and manifest correlations. Here, manifest correlation refers to correlation between observed scores, while latent correlation refers to correlation between scores at the latent (e.g., logit or probit) scale. Thus, using one in place of the other can lead to erroneous conclusions. Taylor series based reliability measures, which are based on manifest correlation functions, are derived and a careful comparison of reliability measures based on latent correlations, Fisher's information, and exact reliability is carried out. The latent correlations are virtually always considerably higher than their manifest counterparts, Fisher's information measure shows no coherent behaviour (it is even negative in some cases), while the newly introduced Taylor series based approximations reflect the exact reliability very closely. Comparisons among the various types of correlations, for various IRT models, are made using algebraic expressions, Monte Carlo simulations, and data analysis. Given the light computational burden and the performance of Taylor series based reliability measures, their use is recommended. PMID:24484622

Milanzi, Elasma; Molenberghs, Geert; Alonso, Ariel; Verbeke, Geert; De Boeck, Paul

2015-02-01

385

Digital image correlation method for measuring thermal deformation of composite materials  

NASA Astrophysics Data System (ADS)

Thermal deformation measurement of the high-speed aircrafts under the high temperature is significant for reliability assessment, life prediction, and safety design for the materials and structures. This paper presents a digital image correlation method to accurately measure the full-field thermal deformation of composites under the environment of high temperature. First, real-time deformation images of experimental objects under different loads are acquired with CCD cameral. Based on the digital speckle correlation theory, the bilinear interpolation algorithm is employed to measure the thermal deformation. Last, the comparative analyses on measurement results by the proposed and traditional methods are conducted, as well as factors impacting measurement errors are analyzed.

Jiang, Li; He, Yan; Wang, Dong-wei; Liu, Ke; Wu, Wei-ren

2013-10-01

386

Surface roughness measurement on a wing aircraft by speckle correlation.  

PubMed

The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given. PMID:24013488

Salazar, Félix; Barrientos, Alberto

2013-01-01

387

Surface Roughness Measurement on a Wing Aircraft by Speckle Correlation  

PubMed Central

The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given. PMID:24013488

Salazar, Félix; Barrientos, Alberto

2013-01-01

388

Correlation Attenuation Due to Measurement Error: A New Approach Using the Bootstrap Procedure  

ERIC Educational Resources Information Center

Issues with correlation attenuation due to measurement error are well documented. More than a century ago, Spearman proposed a correction for attenuation. However, this correction has seen very little use since it can potentially inflate the true correlation beyond one. In addition, very little confidence interval (CI) research has been done for…

Padilla, Miguel A.; Veprinsky, Anna

2012-01-01

389

MMPI2 Correlates of Sexual Preoccupation as Measured by the Sexuality Scale in a College Setting  

Microsoft Academic Search

The current study explored associations between MMPI-2 scales and a measure of sexual preoccupation college students. Participants were 846 undergraduate students at a Midwestern university who completed the MMPI-2 and Sexuality Scale. Correlational analyses were conducted by gender to identify significant relations, which were then examined for potential gender differences. Results indicated significant correlations between sexual preoccupation scores and a

Tayla Lee; Johnathan D. Forbey

2010-01-01

390

Measurement of the Vaporization Enthalpy of Complex Mixtures by Correlation-Gas Chromatography. The  

E-print Network

Measurement of the Vaporization Enthalpy of Complex Mixtures by Correlation-Gas Chromatography April 21, 2005. Revised Manuscript Received June 2, 2005 The use of correlation-gas chromatography using gas chromatography. Some variance in composition with the literature values has been observed

Chickos, James S.

391

A Brief Measure of Worry Severity (BMWS): personality and clinical correlates of severe worriers  

Microsoft Academic Search

This report describes the development of a brief and valid self-report measure to assess severe and dysfunctional worry (the Brief Measure of Worry Severity or BMWS). Using three independent subject groups (clinical and non-clinical), the measure was used to examine the differential severity of worry in depression and anxiety and to examine the clinical and personality correlates of severe worriers.

Gemma L. Gladstone; Gordon B. Parker; Philip B. Mitchell; Gin S. Malhi; Kay A. Wilhelm; Marie-Paule Austin

2005-01-01

392

Field methods to measure surface displacement and strain with the Video Image Correlation method  

NASA Technical Reports Server (NTRS)

The objective of this project was to develop methods and application procedures to measure displacement and strain fields during the structural testing of aerospace components using paint speckle in conjunction with the Video Image Correlation (VIC) system.

Maddux, Gary A.; Horton, Charles M.; Mcneill, Stephen R.; Lansing, Matthew D.

1994-01-01

393

Identification of Noise Sources in High Speed Jets via Correlation Measurements: A Review  

NASA Technical Reports Server (NTRS)

Significant advancement has been made in the last few years to identify noise sources in high speed jets via direct correlation measurements. In this technique turbulent fluctuations in the flow are correlated with far field acoustics signatures. In the 1970 s there was a surge of work using mostly intrusive probes, and a few using Laser Doppler Velocimetry, to measure turbulent fluctuations. The later experiments established "shear noise" as the primary source for the shallow angle noise. Various interpretations and criticisms from this time are described in the review. Recent progress in the molecular Rayleigh scattering based technique has provided a completely non-intrusive means of measuring density and velocity fluctuations. This has brought a renewed interest on correlation measurements. We have performed five different sets of experiments in single stream jets of different Mach number, temperature ratio and nozzle configurations. The present paper tries to summarize the correlation data from these works.

Bridges, James (Technical Monitor); Panda, Jayanta

2005-01-01

394

3D topography measurements on correlation cells—a new approach to forensic ballistics identifications  

NASA Astrophysics Data System (ADS)

Based on three-dimensional (3D) topography measurements on correlation cells, the National Institute of Standards and Technology (NIST) has developed the ‘NIST Ballistics Identification System (NBIS)’ aimed at accurate ballistics identifications and fast ballistics evidence searches. The 3D topographies are divided into arrays of correlation cells to identify ‘valid correlation areas’ and eliminate ‘invalid correlation areas’ from the matching and identification procedure. A ‘congruent matching cells’ (CMC)’ method using three types of identification parameters of the paired correlation cells (cross correlation function maximum CCFmax, spatial registration position in x-y and registration angle ?) is used for high accuracy ballistics identifications. ‘Synchronous processing’ is proposed for correlating multiple cell pairs at the same time to increase the correlation speed. The proposed NBIS can be used for correlations of both geometrical topographies and optical intensity images. All the correlation parameters and algorithms are in the public domain and subject to open tests. An error rate reporting procedure has been developed that can greatly add to the scientific support for the firearm and toolmark identification specialty, and give confidence to the trier of fact in court proceedings. The NBIS is engineered to employ transparent identification parameters and criteria, statistical models and correlation algorithms. In this way, interoperability between different ballistics identification systems can be more easily achieved. This interoperability will make the NBIS suitable for ballistics identifications and evidence searches with large national databases, such as the National Integrated Ballistic Information Network in the United States.

Song, John; Chu, Wei; Tong, Mingsi; Soons, Johannes

2014-06-01

395

Velocity-pressure correlation measurement based on planar PIV and miniature static pressure probes  

NASA Astrophysics Data System (ADS)

This study aimed to measure pressure-related turbulence statistics such as the velocity-pressure or the pressure-strain correlations. To do so, the pressure field evaluation based on the velocity data measured by particle image velocimetry (PIV) was combined with direct single-point-measurement by miniature static pressure probes (SP-probe). The instantaneous pressure field was derived from the measurement results by PIV, and the pressure fluctuations associated with the large-scale vortex motion were extracted using the instantaneous pressure directly measured by the SP-probe as a reference signal. The measurement was taken in a turbulent near wake of a circular cylinder. After the validity of the instantaneous pressure evaluated from the PIV data was addressed, the velocity-pressure correlation and the pressure-strain correlation were investigated.

Kawata, Takuya; Obi, Shinnosuke

2014-07-01

396

Correlation of inflight neutron dosimeter and SEU measurements with atmospheric neutron model  

Microsoft Academic Search

Inflight measurements during high-altitude flight (NVB-57 and ER-2) of a simple neutron dosimeter, the PDM-303, correlate well with the NASA-Langley atmospheric neutron model. Based on simultaneous measurements with the much more accurate tissue equivalent proportional counter, the PDM-303 response has been calibrated in absolute terms for high-altitude flight. Thus the PDM-303 output is correlated with the fluence of atmospheric neutrons

Eugene Normand

2001-01-01

397

Schrödinger uncertainty relation, Wigner-Yanase-Dyson skew information and metric adjusted correlation measure  

E-print Network

In this paper, we give a Schr\\"odinger-type uncertainty relation using the Wigner-Yanase-Dyson skew information. In addition, we give Schr\\"odinger-type uncertainty relation by use of a two-parameter extended correlation measure. Moreover, we give the further generalization for Schr\\"odinger-type uncertainty relation by metric adjusted correlation measure. These results generalize our previous result in [Phys. Rev. A, Vol.82(2010), 034101].

Shigeru Furuichi; Kenjiro Yanagi

2010-10-03

398

Semiconductor thin-film optical constant determination and thin-film thickness measurement equipment correlation  

NASA Astrophysics Data System (ADS)

There are several methods for correlating thin film thickness measurement equipment. The most commonly used method is to program in an offset that gets systematically added to or subtracted from the thickness calculation. Measurement errors can occur using this 'fudge factor' method because the relationship between the reference thicknesses and the measured thicknesses is not, in general, a fixed constant or simple function. A better method for correlating thin film thickness measurement equipment is to tune the instruments to the process by refining the internal optical constants.

Kaiser, Anne M.

1991-07-01

399

Quantum Fisher information as the measure of Gaussian quantum correlation: Role in quantum metrology  

E-print Network

We have introduced a measure of Gaussian quantum correlations based on quantum Fisher information. For bipartite Gaussian states the minimum quantum Fisher information due to local unitary evolution on one of the parties reliably quantifies quantum correlation. In quantum metrology the proposed measure becomes the tool to investigate the role of quantum orrelation in setting metrological precision. In particular, a deeper insights can be gained on how quantum correlations are instrumental to enhance metrological precision. Our analysis demonstrates that not only entanglement but also quantum correlation plays an important role to enhance metrological precision. Clearly unraveling the underlaying mechanism we show that quantum correlations, even in the absence of entanglement, can be exploited as the resource to beat standard quantum limit and attain Heisenberg limit in quantum metrology.

Manabendra N. Bera

2014-06-19

400

Particle image velocimetry correlation signal-to-noise ratio metrics and measurement uncertainty quantification  

NASA Astrophysics Data System (ADS)

In particle image velocimetry (PIV) the measurement signal is contained in the recorded intensity of the particle image pattern superimposed on a variety of noise sources. The signal-to-noise-ratio (SNR) strength governs the resulting PIV cross correlation and ultimately the accuracy and uncertainty of the resulting PIV measurement. Hence we posit that correlation SNR metrics calculated from the correlation plane can be used to quantify the quality of the correlation and the resulting uncertainty of an individual measurement. In this paper we extend the original work by Charonko and Vlachos and present a framework for evaluating the correlation SNR using a set of different metrics, which in turn are used to develop models for uncertainty estimation. Several corrections have been applied in this work. The SNR metrics and corresponding models presented herein are expanded to be applicable to both standard and filtered correlations by applying a subtraction of the minimum correlation value to remove the effect of the background image noise. In addition, the notion of a ‘valid’ measurement is redefined with respect to the correlation peak width in order to be consistent with uncertainty quantification principles and distinct from an ‘outlier’ measurement. Finally the type and significance of the error distribution function is investigated. These advancements lead to more robust and reliable uncertainty estimation models compared with the original work by Charonko and Vlachos. The models are tested against both synthetic benchmark data as well as experimental measurements. In this work, {{U}68.5} uncertainties are estimated at the 68.5% confidence level while {{U}95} uncertainties are estimated at 95% confidence level. For all cases the resulting calculated coverage factors approximate the expected theoretical confidence intervals, thus demonstrating the applicability of these new models for estimation of uncertainty for individual PIV measurements.

Xue, Zhenyu; Charonko, John J.; Vlachos, Pavlos P.

2014-11-01

401

A K-band central disk surface-brightness correlation with scale-length for early-type disk galaxies, and the inclination correction  

E-print Network

The K-band light-profiles from two statistically complete, diameter-limited samples of disk galaxies have been simultaneously modelled with a seeing-convolved Sersic r^{1/n} bulge and a seeing-convolved exponential disk. This has enabled an accurate separation of the bulge and disk light, and hence an estimate of the central disk surface brightness mu_{0,K} and the disk scale-length h. There exists a bright envelope of galaxy disks in the mu_{0,K}-log h diagram; for the early-type (50 deg) galaxies having morphological types ranging from S0 to Sc, the need for an inclination correction to the K-band disk surface brightness is demonstrated. Measured central disk surface brightnesses are found to be significantly (>5-sigma) brighter for the high-inclination disk galaxies than for the low-inclination disk galaxies. With no surface brightness inclination correction or allowance for the trend between mu_{0,K} and log h, the standard deviation to the distribution of mu_{0,K} values is ~1 mag arcsec^{-2}, while the standard deviation about the mean mu_{0,K}-log h relation decreases from 0.69 mag arcsec^{-2}, when no inclination correction is applied, to 0.47 mag arcsec^{-2} when the inclination correction is applied.

Alister W. Graham

2001-04-06

402

Correlation  

NSDL National Science Digital Library

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

Pennilyn Higgins

403

Outcome of carpal tunnel release - Correlation with wrist and wrist-palm anthropomorphic measurements.  

PubMed

Wrist and wrist-palm measurements have been associated with the diagnosis of carpal tunnel syndrome. We found no reported study about how this correlation affects the outcome after surgery. We investigated the role of the measurements in predicting outcome after open carpal tunnel release. A total of 131 patients (88 female, 43 male) responded to our postal questionnaire using the Boston Carpal Tunnel assessment (65% response rate) at a minimum of 9 months post-operatively. Symptom and functional scores showed a strong correlation. There was no statistical difference in the outcome between wrist ratio (?0.7 vs <0.7), wrist-palm ratio (?0.41 vs <0.41) and gender, but a better functional score was very weakly correlated with a higher wrist ratio. A very large study would be needed to show any statistical correlation between both measurement and outcome. PMID:24554691

Lee, L H; Al-Maiyah, M; Al-Bahrani, R Z; Bhargava, A; Auyeung, J; Stothard, J

2015-02-01

404

Accurate measurement of wall skin friction by single-pixel ensemble correlation  

NASA Astrophysics Data System (ADS)

The present work deals with accurately estimating wall-skin friction from near-wall mean velocity by means of PIV measurement. The estimation accuracy relies on the spatial resolution and the precision of the resolved velocity profile inside the viscous sublayer, which is a big challenge for conventional window-based correlation method (Kähler C J, et al. Exp Fluids, 2012, 52: 1641-1656). With the help of single-pixel ensemble correlation, the ensemble-averaged velocity vector can be resolved at significant spatial resolution, thus improving the measurement accuracy. To demonstrate the feasibility of this single-pixel ensemble correlation method, we first study the velocity estimation precision in a case of steady near-wall flow. Synthetic particle images are used to investigate the effect of different image parameters. It is found that the velocity RMS-uncertainty level of the single-pixel ensemble correlation method can be equivalent to the conventional window correlation method once the effective particle number used for the ensemble correlation is large enough. Furthermore, a canonical turbulent boundary layer is synthetically simulated based on velocity statistics resolved by previous Direct Numerical Simulation (DNS) work (Schlatter P, et al. J Fluid Mech, 2010, 659: 116-126). The relative error of wall skin friction coefficient is shown to be one-order smaller than that of the window correlation method. And the optimization strategy to further minimize the measurement uncertainty is discussed in the last part.

Shen, JunQi; Pan, Chong; Wang, JinJun

2014-07-01

405

Discrete EKF with pairwise Time Correlated Measurement Noise for Image-Aided Inertial Integrated Navigation  

NASA Astrophysics Data System (ADS)

An image-aided inertial navigation implies that the errors of an inertial navigator are estimated via the Kalman filter using the aiding measurements derived from images. The standard Kalman filter runs under the assumption that the process noise vector and measurement noise vector are white, i.e. independent and normally distributed with zero means. However, this does not hold in the image-aided inertial navigation. In the image-aided inertial integrated navigation, the relative positions from optic-flow egomotion estimation or visual odometry are pairwise correlated in terms of time. It is well-known that the solution of the standard Kalman filter becomes suboptimal if the measurements are colored or time-correlated. Usually, a shaping filter is used to model timecorrelated errors. However, the commonly used shaping filter assume that the measurement noise vector at epoch k is not only correlated with the one from epoch k - 1 but also with the ones before epoch k - 1 . The shaping filter presented in this paper uses Cholesky factors under the assumption that the measurement noise vector is pairwise time-correlated i.e. the measurement noise are only correlated with the ones from previous epoch. Simulation results show that the new algorithm performs better than the existing algorithms and is optimal.

Gopaul, N. S.; Wang, J. G.; Hu, B.

2014-11-01

406

Cell and tissue deformation measurements: texture correlation with third-order approximation of displacement gradients.  

PubMed

Cells remarkably are capable of large deformations during motility and when subjected to mechanical force. Measurement of mechanical deformation (i.e. displacements, strain) is critical to understand functional changes in cells and biological tissues following disease, and to elucidate basic relationships between applied force and cellular biosynthesis. Microscopy-based imaging modalities provide the ability to noninvasively visualize small cell or tissue structures and track their motion over time, often using two-dimensional (2D) digital image (texture) correlation algorithms. For the measurement of complex and nonlinear motion in cells and tissues, implementation of texture correlation algorithms with high order approximations of displacement mapping terms are needed to minimize error. Here, we extend a texture correlation algorithm with up to third-order approximation of displacement mapping terms for the measurement of cell and tissue deformation. We additionally investigate relationships between measurement error and image texture, defined by subset entropy. Displacement measurement error is significantly reduced when the order of displacement mapping terms in the texture correlation algorithm matches or exceeds the order of the deformation observed. Displacement measurement error is also inversely proportional to subset entropy, with well-defined cell and tissue structures leading to high entropy and low error. For cell and tissue studies where complex or nonlinear displacements are expected, texture correlation algorithms with high order terms are required to best characterize the observed deformation. PMID:23992835

Lim, Kai Y; Henderson, Jonathan T; Neu, Corey P

2013-09-27

407

Circumference and Arc Length  

NSDL National Science Digital Library

This unit will introduce you to circumference of a circle, and how to find the measurement of the edge of a piece of pizza! (Arc length!) Ok. Let's make sure you remember circumference of a circle, you know, the distance around a circle? Click on the following link and take notes! Circle Circumference Now we can use that to find the arc length, or the length of the crust part of the edge of a pizza! Take notes: Arcs in Circles Now, let's ...

Neubert, Mrs.

2011-03-24

408

Correlation Between Opacity and Surface Water Vapor Pressure Measurements at Rio Frio  

E-print Network

Correlation Between Opacity and Surface Water Vapor Pressure Measurements at Rio Frio M.A. Holdaway 1, 1996 Abstract We use the surface water vapor pressure measured by weather stations at 4060 m opacity. The surface water vapor pressure is inverted some 20% of the time at night and some 35

Groppi, Christopher

409

CORRELATION IN UNCERTAINTY OF MEASUREMENT - A DISCUSSION OF STATE OF THE ART TECHNIQUES  

Microsoft Academic Search

The Guide to the expression of uncertainty has been around for 15 years and has been widely adopted by science and industry. Over time more and more complex measurements are evaluated based on these principles. As a consequence the correlation between quantities has become an important issue in the evaluation of measurement uncertainty. In this paper we will give an

Rüdiger Kessel; Raghu Kacker

410

Chemical oxygen diffusion coefficient measurement by conductivity relaxation--correlation between tracer diffusion  

E-print Network

Chemical oxygen diffusion coefficient measurement by conductivity relaxation--correlation between J. P., Grenier J. C., Loup J. P. ABSTRACT Chemical oxygen diusion coecient ¯(D)was measured the oxygen partial pressure in the surrounding atmosphere of the sample. The consequent evolution

Paris-Sud XI, Université de

411

Correlation of seismotectonic variables and GPS strain measurements in western Turkey  

E-print Network

Correlation of seismotectonic variables and GPS strain measurements in western Turkey Ali Osman O Mediterranean and western Turkey area. This analysis was conducted in three tectonic subdivisions corresponding measurements in western Turkey, J. Geophys. Res., 109, B11306, doi:10.1029/2004JB003101. 1. Introduction [2

Wilson, Thomas H.

412

Linear smoothing using measurements containing correlated noise with an application to inertial navigation  

Microsoft Academic Search

Kalman and Bucy [1] derived the maximum likelihood filter for continuous linear dynamic systems where all measurements contain white noise, i.e., noise with short correlation times compared to response times of the dynamic system. The corresponding maximum likelihood smoother was described in [2]. The maximum likelihood filter was presented in [3] for the case in which some measurements contain either

R. Mehra

1968-01-01

413

Validation of SAGE II aerosol measurements by comparison with correlative sensors  

NASA Technical Reports Server (NTRS)

The SAGE II limb-scanning radiometer carried on the Earth Radiation Budget Satellite functions at wavelengths of 0.385, 0.45, 0.525, and 1.02 microns to identify vertical profiles of aerosol density by atmospheric extinction measurements from cloud tops upward. The data are being validated by correlating the satellite data with data gathered with, e.g., lidar, sunphotometer, and dustsonde instruments. Work thus far has shown that the 1 micron measurements from the ground and satellite are highly correlated and are therefore accurate to within measurement uncertainty.

Swissler, T. J.

1986-01-01

414

Submaximal delayed-onset muscle soreness: correlations between MR imaging findings and clinical measures  

NASA Technical Reports Server (NTRS)

PURPOSE: To assess correlations between muscle edema on magnetic resonance (MR) images and clinical indexes of muscle injury in delayed-onset muscle soreness (DOMS) produced by submaximal exercise protocols. MATERIALS AND METHODS: Sixteen subjects performed 36 elbow flexions ("biceps curls") at one of two submaximal workloads that emphasized eccentric contractions. Changes in MR imaging findings, plasma levels of creatine kinase, and pain scores were correlated. RESULTS: Both exercise protocols produced DOMS in all subjects. The best correlation was between change in creatine kinase level and volume of muscle edema on MR images, regardless of the workload. Correlations tended to be better with the easier exercise protocol. CONCLUSION: Whereas many previous studies of DOMS focused on intense exercise protocols to ensure positive results, the present investigation showed that submaximal workloads are adequate to produce DOMS and that correlations between conventionally measured indexes of injury may be enhanced at lighter exercise intensities.

Evans, G. F.; Haller, R. G.; Wyrick, P. S.; Parkey, R. W.; Fleckenstein, J. L.; Blomqvist, C. G. (Principal Investigator)

1998-01-01

415

Detecting initial system-environment correlations: Performance of various distance measures for quantum states  

NASA Astrophysics Data System (ADS)

We study the time evolution of four distance measures in the presence of initial system-environment correlations. It is well known that the trace distance between two quantum states of an open system may increase due to initial correlations, which leads to a breakdown of the contractivity of the reduced dynamics. Here we compare and analyze, for two different models, the time evolution of the trace distance, the Bures metric, the Hellinger distance, and the Jensen-Shannon divergence regarding an increase above their initial values, witnessing initial correlations. This work generalizes, deepens, and corrects a part of the study performed by Dajka [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.84.032120 84, 032120 (2011)] and thereby reveals generic features of the considered distance measures with respect to the capability of detecting initial system-environment correlations.

Wißmann, S.; Leggio, B.; Breuer, H.-P.

2013-08-01

416

Photoacoustic correlation spectroscopy and its application to low-speed flow measurement.  

PubMed

A photoacoustic correlation technique, inspired by its optical counterpart-the fluorescence correlation spectroscopy (FCS)-was tested for the first time, to our knowledge, to demonstrate the feasibility of low-speed flow measurement based on photoacoustic signal detection. A pulsed laser was used to probe the flow of light-absorbing beads. A photoacoustic correlation system of 0.8 s temporal resolution was built and flow speeds ranging from 249 to 14.9 microm/s with corresponding flow times from 4.42 to 74.1 s were measured. The experiment serves as a proof of concept for photoacoustic correlation spectroscopy, which may have many potential applications similar to the FCS. PMID:20410966

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

2010-04-15

417

Focusing in Arthurs-Kelly-type Joint Measurements with Correlated Probes  

E-print Network

Joint approximate measurement schemes of position and momentum provide us with a means of inferring pieces of complementary information if we allow for the irreducible noise required by quantum theory. One such scheme is given by the Arthurs-Kelly model, where information about a system is extracted via indirect probe measurements. So far, only separable uncorrelated probes have been considered. Here, following Di Lorenzo (PRL 110, 120403 (2013)), we extend this model to both entangled and classically correlated probes, achieving full generality. We find the measured observable of the system under consideration to be covariant under phase space translations, and show that correlated probes can produce more precise joint measurement outcomes of position and momentum than the same probes can achieve if applied alone to realize a position or momentum measurement. Contrary to Di Lorenzo's claim, we find that nevertheless there are no violations of Heisenberg's measurement uncertainty relations in these generalized Arthurs-Kelly models.

Thomas J Bullock; Paul Busch

2014-09-16

418

Correlations between body measurements and tissue composition of oat-fattened White Ko?uda geese at 17 weeks of age.  

PubMed

1. The aim of the present study was to evaluate the yield and tissue composition of carcases from White Ko?uda ganders (males) and geese (females), and to determine the relationships between body measurements and carcase tissue composition. 2. The experiment was carried out on 200 geese (100 males and 100 females) reared to 14 weeks of age and then fed with oats for the next 3 weeks. Live body weight and body dimensions, slaughter yield, weight and percentage of muscles and skin with fat in carcase were measured and correlation coefficients were calculated between body measurements and slaughter values and carcase tissue composition. 3. White Ko?uda geese reared to 17 weeks of age were characterised by high body weight (6705 g) and good muscle yield (29.9%). Males had greater body weight, musculature and fatness than females. Sternum length and breast circumference, width and depth were good indicators of carcase muscle weight in 17-week-old geese. 4. Negative coefficients of correlation between sternum length and weight of skin with subcutaneous fat indicate that increased selection pressure in pedigree flocks of geese on sternum length should be paralleled by reduced carcase fatness in these birds. PMID:18210286

Lukaszewicz, E; Adamski, M; Kowalczyk, A

2008-01-01

419

The effect of high column density systems on the measurement of the Lyman-? forest correlation function  

NASA Astrophysics Data System (ADS)

We present a study of the effect of High Column Density (HCD) systems on the Ly? forest correlation function on large scales. We study the effect both numerically, by inserting HCD systems on mock spectra for a specific model, and analytically, in the context of two-point correlations and linear theory. We show that the presence of HCDs substantially contributes to the noise of the correlation function measurement, and systematically alters the measured redshift-space correlation function of the Ly? forest, increasing the value of the density bias factor and decreasing the redshift distortion parameter ?? of the Ly? forest. We provide simple formulae for corrections on these derived parameters, as a function of the mean effective optical depth and bias factor of the host halos of the HCDs, and discuss the conditions under which these expressions should be valid. In practice, precise corrections to the measured parameters of the Ly? forest correlation for the HCD effects are more complex than the simple analytical approximations we present, owing to non-linear effects of the damped wings of the HCD systems and the presence of three-point terms. However, we conclude that an accurate correction for these HCD effects can be obtained numerically and calibrated with observations of the HCD-Ly? cross-correlation. We also discuss an analogous formalism to treat and correct for the contaminating effect of metal lines overlapping the Ly? forest spectra.

Font-Ribera, Andreu; Miralda-Escudé, Jordi

2012-07-01

420

The effect of high column density systems on the measurement of the Lyman-? forest correlation function  

SciTech Connect

We present a study of the effect of High Column Density (HCD) systems on the Ly? forest correlation function on large scales. We study the effect both numerically, by inserting HCD systems on mock spectra for a specific model, and analytically, in the context of two-point correlations and linear theory. We show that the presence of HCDs substantially contributes to the noise of the correlation function measurement, and systematically alters the measured redshift-space correlation function of the Ly? forest, increasing the value of the density bias factor and decreasing the redshift distortion parameter ?{sub ?} of the Ly? forest. We provide simple formulae for corrections on these derived parameters, as a function of the mean effective optical depth and bias factor of the host halos of the HCDs, and discuss the conditions under which these expressions should be valid. In practice, precise corrections to the measured parameters of the Ly? forest correlation for the HCD effects are more complex than the simple analytical approximations we present, owing to non-linear effects of the damped wings of the HCD systems and the presence of three-point terms. However, we conclude that an accurate correction for these HCD effects can be obtained numerically and calibrated with observations of the HCD-Ly? cross-correlation. We also discuss an analogous formalism to treat and correct for the contaminating effect of metal lines overlapping the Ly? forest spectra.

Font-Ribera, Andreu [Institut de Ciències de l'Espai (IEEC-CSIC), E. de Ciències, Torre C5, Bellaterra, Catalonia (Spain); Miralda-Escudé, Jordi, E-mail: font@physik.uzh.ch, E-mail: miralda@icc.ub.edu [Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia (Spain)

2012-07-01

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Development and Psychometric Evaluation of a New Instrument for Measuring Sleep Length and Television and Computer Habits of Swedish School-Age Children  

ERIC Educational Resources Information Center

The aim was to develop a new instrument for measuring length of sleep as well as television and computer habits in school-age children. A questionnaire was constructed for use when children visit the school health care unit. Three aspects of the validity of the questionnaire were examined: its face validity, content validity, and construct…

Garmy, Pernilla; Jakobsson, Ulf; Nyberg, Per

2012-01-01

422

Recovery behavior of point defects after low-dose neutron irradiation at ˜423 K of sintered 6H-SiC by lattice parameter and macroscopic length measurements  

NASA Astrophysics Data System (ADS)

To evaluate neutron-irradiation-induced crystalline defects and its thermal stability, ?-SiC sintered bodies consisting of mainly 6H polytype were neutron irradiated using the Japan Materials Testing Reactor up to 1.9 × 1023 n/m2 (E > 0.1 MeV) at a low temperature of ˜423 K. Due to very low dose irradiation at low temperature, expected defects induced into crystalline lattice should only be simple point defects. Changes in the lattice parameters and macroscopic lengths resulting from post-irradiation isothermal annealing up to 6 h between room temperature and 1673 K were measured. Macroscopic volume swelling of ?-SiC specimens coincided well to those of unit cell volume changes, indicating the presence of only simple defects. The recovery behavior of the macroscopic length and lattice parameters showed almost the same tendencies, although residual changes in the c-axis length slightly exceeded that of the a-axis length at temperatures lower than 1273 K. Difference in these axes lengths diminished at temperatures above 1273 K. Calculation of activation energies, obtained from precise length measurement using a dilatometer during each isothermal annealing step, revealed that length recovery behavior between 473 and 1573 K could almost be completely explained by a first-order reaction, and three stages with activation energies of 0.14, 0.26,